| Largemouth bass consumption demand on hatchery rainbow trout in two Washington lakes | David R. Christensen; Barry C. Moore | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 3 | 2010 | 200 - 211 | Largemouth bass consumption demand on hatchery rainbow trout in two Washington lakes | High mortality (84-89%) of stocked rainbow trout (Oncorhynchus mykiss) in Twin Lakes, Washington, has been partially blamed on predation from non-native largemouth bass (Micropterus salmoides). We examined the gut-content of 434 largemouth bass and applied a bioenergetics model to determine the consumption demand on hatchery-released rainbow trout and other prey species in the Twin Lakes. Largemouth bass consumed approximately 4915 (95% CI; 2393-13,452) fall stocked rainbow trout in South Twin. No rainbow trout consumption was observed in North Twin, despite a similar stocking regime. Approximately 6.3% (95% CI; 3-17%) of total fall stocked rainbow trout in South Twin were consumed by largemouth bass. Rainbow trout stocked in the fall ranged from 100 to 160 mm total length and were all subject to predation by large largemouth bass ≥300 mm. Large largemouth bass consumed rainbow trout that reached up to 210 mm in length and 58% of bass body length. No predation was observed on larger rainbow trout (215-370 mm) stocked during the spring. Smaller largemouth bass ≤299 mm consumed primarily invertebrates, including crayfish, and did not consume rainbow trout in either lake. During spring and summer in South Twin Lake, large largemouth bass consumed principally golden shiner (Notemigonus crysoleucas) and crayfish. In North Twin Lake, golden shiner constituted most of the larger bass diet for the entire year. Differences in macrophyte distribution, bathymetry, temperature and/or predator-prey demographics likely influenced variability in largemouth bass predation between lakes. Largemouth bass predation did not account for overall rainbow trout mortality. |
| Public preferences and values for management of aquatic invasive plants in state parks | Damian C. Adams; Santiago Bucaram; Donna J. Lee; Alan W. Hodges | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 3 | 2010 | 185 - 193 | Public preferences and values for management of aquatic invasive plants in state parks | Alien invasive plants (AIP) significantly impact the ecology of natural areas and nature-based recreation, yet control programs are chronically underfunded. This study examined Florida residents' willingness-to-pay (WTP) to control aquatic AIP in river and lake state parks through entrance fees. We used a method commonly applied in the nonmarket valuation literature, but not previously applied to AIP, and found that residents have a high WTP to control AIP and are willing to support control programs through entrance fees. In 2007, we surveyed 1299 Florida residents to estimate the impact of AIP on state park recreation. The survey included conjoint choice questions to establish the impact of several park attributes on respondents' economic utility or welfare: abundance of AIP, entrance fees, park facilities, abundance of native plant species, and abundance of native animal species. Using entrance fees as a payment vehicle, we estimated that the typical Florida resident has a per-visit WTP of $6.15 to reduce AIP coverage, $4.41 to improve park facilities, $3.81 to increase the abundance of native plants, and $4.99 to increase the abundance for native animals. We used annual attendance data from 63 river and lake state parks to calculate statewide WTP to control AIP and found that local residents are willing to spend $12.26 million/yr, and all users are willing to spend $35.01 million/yr to keep AIP from becoming “numerous and dense†in the 63 parks. This far outweighs the $26 million/yr that the state is currently spending in all natural areas, including state parks. |
| Spatial and temporal patterns of nearshore clarity in Lake Tahoe from fine resolution turbidity measurements | Margaret A. Shanafield; Richard B. Susfalk; Kendrick C. Taylor | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 3 | 2010 | 178 - 184 | Spatial and temporal patterns of nearshore clarity in Lake Tahoe from fine resolution turbidity measurements | The nearshore areas of lakes respond quickly to watershed runoff, increases in tributary inflows from annual snowmelt, and increased anthropogenic activity in the basin. Therefore, this area of the lake serves both as an early warning system for water quality degradation and as an indicator of the effectiveness of land management practices or sediment control projects. In this study we evaluated the usefulness of combining fine-scale water quality measurements and discrete particle sample analysis to gain a better understanding of seasonal and spatial trends in the nearshore area of Lake Tahoe. Turbidity and mineral composition at 0.5 m depth were measured in nearshore waters near the City of South Lake Tahoe at a spatial resolution of 5-30 m in 2002 and 2003. Particles filtered from discrete samples collected 200 m from shore were analyzed by scanning electron microscopy and chemical analysis using quantum electron dispersive spectrometry. Baseline turbidity levels were extremely low (0.15 NTU) during calm periods in the fall but rose to levels above 4.0 NTU in response to winter and spring precipitation events and spring snowmelt runoff. Discrete samples collected 200 m from shore contained over 80% organic material during the dry part of the year and at least 50% mineral particles during the winter and spring. The effectiveness of this method for detecting variability in nearshore conditions at Lake Tahoe is promising for monitoring the littoral areas of other pristine lakes facing increased anthropogenic pressure and other watershed disturbances. |
| Using GIS to estimate lake volume from limited data | Jeffrey Hollister; W. Bryan Milstead | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 3 | 2010 | 194 - 199 | Using GIS to estimate lake volume from limited data | Estimates of lake volume are necessary for calculating residence time and modeling pollutants. Modern GIS methods for calculating lake volume improve on more dated technologies (e.g., planimeters) and do not require potentially inaccurate assumptions (e.g., volume of a frustum of a cone), but most GIS methods do require detailed bathymetric data, which may be unavailable. GIS technology cannot correct for a lack of data; however, it can facilitate development of methods that better use the relatively simple and more widely available measurements of lake shape and maximum depth. In this research note we describe a method to model bathymetry and estimate lake volume with a limited set of data that consists only of a maximum depth measurement and a GIS layer of lake shoreline. Using a simple linear transformation, we estimated depth as a function of distance from shoreline and with the resultant information estimated lake volume. We applied and compared this method with estimates derived from field bathymetry data of 129 lakes in New Hampshire. In New Hampshire lakes, the assumption of depth as a function of distance is appropriate, and the simple GIS method has lower overall error than simply using the formula for volume of a cone to estimate lake volume. This approach has broad implications in the assessment of lake condition from national surveys (e.g., US Environmental Protection Agency's National Lakes Assessment) and should improve upon models of nutrients, contaminants and hydrology, even in the absence of detailed bathymetric data. Supplemental materials are available for this article. Go to the publisher's online edition of Lake and Reservoir Management to view the free supplemental file. |
| Manganese sources and cycling in a tropical eutrophic water supply reservoir, Paso Bonito Reservoir, Cuba | Carmen Betancourt; Fanny Jorge; Roberto Suárez; Marc Beutel; Seyoum Gebremariam | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 3 | 2010 | 217 - 226 | Manganese sources and cycling in a tropical eutrophic water supply reservoir, Paso Bonito Reservoir, Cuba | Paso Bonito Reservoir (mean depth = 6.5 m; volume = 8.0 106 m3) is a small raw water reservoir in south-central Cuba. This study evaluated sources of high levels of manganese in the reservoir causing taste and odor problems. Watershed monitoring showed that levels of total manganese (Mn) and total iron (Fe) were high (Mn 0.14-0.64 mg/L; Fe 5.3-12.4 mg/L) during the first flood of the wet season in river sampling stations near historical pyrite mining operations. Monitoring in the reservoir showed that Mn and Fe were present in bottom waters throughout the year, with peak levels (>8 mg/L of Mn and >30 mg/L of Fe) coinciding with low levels of oxygen in summer months. Empirical modeling of Mn concentration in the reservoir water column showed that it correlated significantly with Fe (positive correlation), redox potential (negative correlation) and dissolved oxygen (negative correlation). Statistical evaluation of the temporal cycle of Mn in raw water delivered to the Juan Gonzales Water Treatment Plant showed that Mn accumulation was highly seasonal, peaking annually around September when dissolved oxygen in raw water was at a minimum. Data suggest that during first-flood conditions early in the wet season, mass loading of Mn and Fe from the watershed to the reservoir is high. During the subsequent drier low-flow summer period, external mass loading of metals drops dramatically and the reservoir becomes a large exporter of Mn and Fe as the metals are internally recycled under anaerobic conditions in bottom waters. |
| Food web effects and the disappearance of the spring clear water phase in Onondaga Lake following nutrient loading reductions | Roland W. Wang; Lars G. Rudstam; Thomas E. Brooking; David J. Snyder; Mark A. Arrigo; Edward L. Mills | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 3 | 2010 | 169 - 177 | Food web effects and the disappearance of the spring clear water phase in Onondaga Lake following nutrient loading reductions | The annual spring clear water phase (May-June) in Onondaga Lake, New York, unexpectedly disappeared in 2003 following several years of phosphorus and ammonia loading reductions at the Metropolitan Syracuse Wastewater Treatment Facility (Metro). Mean chlorophyll a concentration during May-June was higher from 2003 to 2007 than from 1990 to 2002, with mean Secchi disk depths <2 m. Large zooplankton (Daphnia sp.) were abundant during April-June before 2003 but were rare from 2003 to 2007, while abundance of small zooplankton (Bosmina longirostris) increased. Alewife (Alosa pseudoharengus) catches from electrofishing surveys dramatically increased in 2003, and hydroacoustic surveys estimated the alewife population to be between 1600 and 2300 fish/ha in spring 2005-2007. The alewife population in 2005 was dominated by a strong 2002 year class. Increasing biomass of the 2002 year class coincided with the timing of the shift from large to small zooplankton in late summer of 2002. This indicates that the strong 2002 alewife year class initiated a classic trophic cascade in Onondaga Lake, causing the decline and continuing low abundance of Daphnia sp. and the disappearance of the spring clear water phase. The increase in alewife may have been associated with decreasing ammonia concentrations following improvement to Metro. Unionized ammonia has been below levels considered toxic to nonsalmonid fish species since 1999, and the ammonia concentration continues to decrease in the lake. Thus, reductions in nutrient loading can lead to unanticipated food web effects causing decreases rather the expected increases in water clarity in the spring-early summer period. |
| Avoidance of strobe lights by zooplankton | Martin J. Hamel; Nathan S. Richards; Michael L. Brown; Steven R. Chipps | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 3 | 2010 | 212 - 216 | Avoidance of strobe lights by zooplankton | Underwater strobe lights can influence the behavior and distribution of fishes and are increasingly used as a technique to divert fish away from water intake structures on dams. However, few studies examine how strobe lights may affect organisms other than targeted species. To gain insight on strobe lighting effects on nontarget invertebrates, we investigated whether underwater strobe lights influence zooplankton distributions and abundance in Lake Oahe, South Dakota. Zooplankton were collected using vertical tows at 3 discrete distances from an underwater strobe light to quantify the influence of light intensity on zooplankton density. Samples were collected from 3 different depth ranges (0-10 m, 10-20 m and 20-30 m) at <1 m, 15 m and ≥100 m distance intervals away from the strobe light. Copepods represented 67.2% and Daphnia spp. represented 23.3% of all zooplankton sampled from 17 August to 15 September 2004. Night time zooplankton densities significantly decreased in surface waters when strobe lights were activated. Copepods exhibited the greatest avoidance patterns, while Daphnia avoidance varied throughout sampling depths. These results indicate that zooplankton display negative phototaxic behavior to strobe lights and that researchers must be cognizant of potential effects to the ecosystem such as altering predator-prey interactions or affecting zooplankton distribution and growth. |
| A combined watershed-water quality modeling analysis of the Lake Waco reservoir: I. Calibration and confirmation of predicted water quality | Joseph D. White; Shane J. Prochnow; Chris T. Filstrup; J. Thad Scott; Bruce W. Byars; Lisa Zygo-Flynn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 147 - 158 | A combined watershed-water quality modeling analysis of the Lake Waco reservoir: I. Calibration and confirmation of predicted water quality | A coupled watershed-reservoir modeling system was applied to the Lake Waco reservoir and watershed to test possible sources of seasonal excess nutrient concentrations in Lake Waco. The Soil Water Assessment Tool (SWAT) was used for modeling watershed production of water and nutrients. This model included small lakes and dairies in the watershed, located spatially using geographic data. For the reservoir, the 2-dimensional, hydrodynamic model CE-Qual-W2 was used with inputs derived from the SWAT simulations. Calibration of the models was based on observed hydrographic information and stream and reservoir nutrient data. The relationship between predicted and observed stream flow values for the North Bosque River, the major tributary to the reservoir, were highly correlated (r2= 0.86) for the calibration period 1997-1998. Predicted daily nutrient values near the inflow of the North Bosque into Lake Waco reservoir were variable but similar to previously estimated annual loading values. Comparison of predicted water quality characteristics from the CE-Qual-W2 model with observed values showed acceptably reliable correspondence seasonally. Chlorophyll-a was used as the main measure for calibration accuracy due to its importance for reservoir management and was predicted to within 6.6% based on the mean percent error or an absolute root mean square error of 9.76 μg/L of observed values. The prediction of stream values from the SWAT model and reservoir nutrient concentrations were sensitive and robust for the next phase of the Comprehensive Lake Waco Study, which includes evaluation of multiple watershed and reservoir management options. |
| Loading of phosphorus and nitrogen to Lake Waco, Texas | Kenneth J. Wagner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 123 - 146 | Loading of phosphorus and nitrogen to Lake Waco, Texas | Cyanobacterial blooms in Lake Waco are linked to nutrient loading from the watershed. Direct measurement of nutrient levels over a period of 8 years facilitates calculation of loading of water, phosphorus (P) and nitrogen (N) to Lake Waco. The North Bosque River (NBR) provides 61% of the flow to Lake Waco, while the Middle Bosque River (MBR) contributes 15.5%. The South Bosque River (SBR) and Hog Creek (HC) each contribute about 7.5% of the total water load to the lake, while other sources contribute less. The lake receives average annual total phosphorus (TP) loading of approximately 147,000 kg and an annual total nitrogen (TN) load of about 1,450,000 kg, with considerable variability expected among years. The NBR contributes 67% of the TP and 37% of the TN. The MBR provides slightly more than 17% of the TP and 41% of the TN. Inputs from SBR are estimated at about 8% of the TP and 10% of the TN. All combined, HC, direct drainage to the lake, atmospheric deposition, ground water inseepage, human inputs associated with recreation, waterfowl inputs and internal loading contribute <8% of the TP and about 12% of the TN. The NBR is clearly the dominant source of TP to the lake, while MBR and NBR contribute roughly equal amounts of TN and much more than any other source. Inputs from wastewater treatment facilities (WWTF) represent about 4% of the TP input and <2% of the TN load to Lake Waco. Despite greater availability of the forms of P in WWTF inputs, this is a minor source for the lake. Inputs from dairy operations, including areas of active animal use and waste application fields, are estimated to contribute 34-42% of the NBR TP load and 23-28% of the overall TP load to Lake Waco. Dairy operations are estimated to contribute about half of the biologically available P load to Lake Waco and generate low N:P ratios in the lake. Despite high loading and resultant blooms, Lake Waco exhibits lower concentrations of P than would be predicted by multiple models, and the actual concentrations stimulate less algal growth than would be expected. In the absence of major inputs related to human activities, the predicted P load to Lake Waco would be less than half the current load, and very little of it would be biologically available. The initial regulatory target of a 50% reduction in P loading to NBR set by the Texas Commission on Environmental Quality is appropriate. If dairy inputs are successfully controlled, measurable improvement can be expected. Supplemental materials are available for this article. Go to the publisher's online edition of Lake and Reservoir Management to view the free supplemental file. |
| Investigation of benthic phosphorus flux controls in Lake Waco, Texas | Marie E. Esten; Kenneth J. Wagner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 114 - 122 | Investigation of benthic phosphorus flux controls in Lake Waco, Texas | Investigations were completed to quantify the amount of phosphorus (P) available for release from the sediment of Lake Waco, Texas, as part of the Lake Waco Comprehensive Lake Management Study. Sediment oxygen demand and benthic nutrient flux measurements were obtained using an in situ chamber and an in situ nutrient analyzer available from Systea Inc. Sediment samples were also collected to determine the amount of loosely sorbed, iron-bound and total P present in the lake sediments by fractionation. Initial results indicated no orthophosphate, nitrate/nitrite or ammonia flux from the sediments into the water column during incubation periods. Sediment fractionation revealed nondetectable loosely sorbed P, low amounts of iron-bound P and moderate total P present in the sediments. Review of these data and comparison with other research suggests that calcium is responsible for controlling P cycling in Lake Waco. This hypothesis was examined by determining the mineral composition of the sediment samples utilizing X-ray diffraction methods. Results indicated the presence of enough calcium-phosphorus minerals to account for all of the total phosphorus reported in the sediments. Unlike many lakes where iron controls P cycling, release of P from calcium compounds in available forms is negligible in Lake Waco, even under anoxic conditions. Management for reduced water column P levels should focus on watershed sources. |
| A combined watershed-water quality modeling analysis of the Lake Waco reservoir: II. Watershed and reservoir management options and outcomes | Joseph D. White; Shane J. Prochnow; Chris T. Filstrup; Bruce W. Byars | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 159 - 167 | A combined watershed-water quality modeling analysis of the Lake Waco reservoir: II. Watershed and reservoir management options and outcomes | In this study, calibrated watershed and reservoir models are used to explore a range of possible watershed conditions and potential management options to reduce available nutrients and algal growth in the Lake Waco reservoir. The management options are divided between watershed and reservoir options. The watershed management options include wetland construction, manure haul-off, agriculture conversion to pasture, absolute nutrient retention in the watershed and control of urban nutrient run-off. For the reservoir, management options of phosphorus inactivation and increased algal consumption by grazers were evaluated. For all individual management scenarios, only complete conversion of agricultural lands into rangeland decreased nutrient levels and algae growth significantly and achieved target levels for chlorophyll-a and total phosphorus. Combined management scenarios including wetland construction, manure haul-off from dairy operations and increased in-reservoir herbivory could further reduce chlorophyll-a and nutrient values, but with less efficiency than agricultural conversion alone. The management option study showed that decreasing nutrient inputs and water clarity were important factors for controlling algal growth in Lake Waco, and that substantial reduction in total phosphorus is needed to achieve target conditions. |
| Lake Waco Comprehensive Study: Background and overview | Thomas M. Conry | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 74 - 79 | Lake Waco Comprehensive Study: Background and overview | As a water supply, Lake Waco, Texas, is subject to the provisions of the Safe Drinking Water Act and related regulations. Aside from concern over primary contaminants that affect human health, there have been taste and odor incidents of increasing frequency, duration and severity over the last decade; therefore, this comprehensive study was developed to define historical and existing water quality conditions and to project possible management scenarios. Practical management approaches to maintain or improve existing water quality conditions within the lake and immediate watershed were identified and evaluated for implementation. The declining water quality within the lake necessitated the construction of an additional treatment process at a cost of $40 million to facilitate compliance with newer drinking water regulations. The investigators sought to assess the magnitude and relative size of water and nutrient contributions to Lake Waco, allowing assessment of loading in relation to acceptable levels for maintaining desired conditions in the reservoir. Thirty-five specific tasks (studies) were conducted concurrently, investigating specific issues or mechanisms of interest in relation to the lake, its watershed and its users. The majority of the $2 million study cost was provided by the City of Waco, although the US Army Corps of Engineers, US Environmental Protection Agency, US Geological Survey, and Texas Parks and Wildlife Department made important contributions to the study. |
| Hot spots and hot moments of planktonic nitrogen fixation in a eutrophic southern reservoir | Robert D. Doyle; J. Thad Scott; Margaret G. Forbes | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 95 - 103 | Hot spots and hot moments of planktonic nitrogen fixation in a eutrophic southern reservoir | Reservoirs have been identified as hot spots of biogeochemical activity, although they are known to exhibit pronounced temporal and spatial variability in planktonic community dynamics. Results from this 19-month study at 5 locations on a southern polymictic reservoir identify pronounced temporal (seasonal and interannual) and significant spatial variability in planktonic nitrogen fixation. Planktonic nitrogen fixation was found to be high during the warmest portion of the year and undetectable for most of the rest of the year. Interannual variability between 2 consecutive summer periods was high and likely due to differences in rainfall pattern and resulting differences in ambient nutrient concentrations and flushing rates. Rates during the dry summer exceeded those during the following summer when unexpected summer rains occurred. Spatial differences in areal and volumetric rates were also significant. Volumetric rates were highest in the inflow transition zone of a river draining a watershed impacted by dairy operations, with inflows exhibiting low N:P ratios. Areal rates were highest in the deeper and clearer portions of the reservoir. Areal rates of nitrogen fixation varied among the 5 stations by a factor of 4.4 in the dry summer and by a factor of 22 in the wetter summer. |
| Sediment transport mechanisms influencing spatiotemporal resuspension patterns in a shallow, polymictic reservoir | Christopher T. Filstrup; Owen T. Lind | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 85 - 94 | Sediment transport mechanisms influencing spatiotemporal resuspension patterns in a shallow, polymictic reservoir | Although whole-lake sedimentation models have been developed for natural lakes, they may not apply to reservoirs due to differing physical, morphological, and hydrodynamic characteristics along a reservoir's longitudinal axis. We measured sedimentation rates immediately below the photic zone and near the sediment surface in a polymictic reservoir's riverine and lacustrine regions to identify transport mechanisms influencing sediment resuspension during an annual cycle. Lake-wide regression models revealed that wind-induced mixing depths explained <20% of sediment resuspension variability. However, site-specific mixing depth models explained 30% of sediment resuspension variability at a lacustrine station. Inverse relationships between mixing depth and sediment resuspension suggested that wind-induced mixing entrained deep-water advective river sediments into the photic zone rather than resuspending deposited sediments. Maximum mixing depths calculated from strong wind events never exceeded site depths, supporting this hypothesis. Lake-wide and site-specific mixing depth models were not improved by considering short-duration, strong wind events, suggesting that episodic winds did not generate enough momentum to effectively deepen mixing depths. Lake-wide regression models indicated that river discharge (r2= 0.19) was a better predictor of sediment resuspension than mixing depth. Site specific discharge models explained 44% and 30% of sediment resuspension variability at 2 riverine stations, emphasizing the influence of horizontal advection in riverine regions. River discharge and wind-induced mixing influenced sediment resuspension at one sampling station only, indicating that the site may have been located in the transition region. Future reservoir sedimentation models should incorporate weighting factors to appropriately represent sediment transport mechanisms along a reservoir's longitudinal axis. |
| The Lake Waco Comprehensive Study: Preface | Thomas M. Conry | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 73 | The Lake Waco Comprehensive Study: Preface | |
| Historical, current, and future economic benefits and costs relating to Lake Waco, Texas | Thomas M. Conry | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 80 - 84 | Historical, current, and future economic benefits and costs relating to Lake Waco, Texas | Lake Waco is an important economic asset for Central Texas. Since 1964, Lake Waco has been utilized as a multiple-purpose reservoir, providing flood protection (more than $258 million in damages prevented), a public drinking water source for 200,000 Central Texans (the City of Waco Utilities Department budget is $40 million per year), and recreational area by up to 2 million people per year. A rise in the conservation pool level increased the drinking water yield by 26 million cubic meters per year but temporarily interfered with recreation. Despite a drop in recreational usage for several years (2001-2005) and significant increases in the quality and quantity of recreational facilities during the pool rise project, the economic impact to local communities remained between $8 and $27 million dollars per year, depending on the method applied. Results from application of the Money Generation Model Version 2 indicate that approximately 750 local jobs are supported by recreational spending. There is a substantial economic return on investments in the enhancement and protection of Lake Waco. |
| The use of carbon-utilization profiling to determine sources of fecal contamination in a central Texas watershed | Michelle D. Nemec; Rene D. Massengale | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 2 | 2010 | 104 - 113 | The use of carbon-utilization profiling to determine sources of fecal contamination in a central Texas watershed | The purpose of this research was to characterize the relationship of Escherichia coli isolates from various animals, sewage, and water based on carbon substrate utilization patterns, and to use these patterns to determine the dominant contributors of nonpoint source fecal pollution to a central Texas reservoir from its watershed. We collected 1028 fecal samples from cattle, companion animals, goat, horse, poultry, sewage, sheep, and wildlife, collectively. From these, 1915 E. coli fecal isolates were analyzed. We collected 100 water samples throughout the North Bosque watershed; 910 E. coli water isolates were analyzed. The Biolog system was used to generate a carbon-utilization pattern for each isolate. A dendrogram constructed from the carbon-utilization patterns demonstrated that isolates from the same source category usually clustered together, excluding water isolates that were spread over many clusters. A bacterial-source tracking library was constructed from the carbon-utilization data obtained from the fecal and sewage isolates and analyzed for internal accuracy. Rates of correct classification for the library ranged from 12.8 to 78.6%. The average rate of correct classification for the library was 45.8%, and specificity values were high, ranging from 75 to 99%. When water isolates were submitted to the library for identification, 43 were classified as originating from cattle, indicating cattle were the dominant source of fecal pollution in the watershed. This was followed by sewage at 27%. Based on these data, our first recommendation for decreasing bacterial pollution in this watershed is to implement strategies that can reduce the contribution of fecal contamination from these 2 sources. |
| Changing water, phosphorus and nitrogen budgets for Valle de Bravo reservoir, water supply for Mexico City Metropolitan Area | Jorge A. RamÃrez-Zierold; MartÃn Merino-Ibarra; Emiliano Monroy-RÃos; Monica Olson; FermÃn S. Castillo; Margarita E. Gallegos; Gloria Vilaclara | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 1 | 2010 | 23 - 34 | Changing water, phosphorus and nitrogen budgets for Valle de Bravo reservoir, water supply for Mexico City Metropolitan Area | Ramrez-Zierold JA, Merino-Ibarra M, Monroy-Ros E, Olson M, Castillo FS, Gallegos ME, Vilaclara G. 2010. 2010. Changing water, phosphorus and nitrogen budgets for Valle de Bravo reservoir, water supply for Mexico City Metropolitan Area. Lake Reserv. Manage. 26:23-34. Valle de Bravo reservoir (VB) provides water supply to the Mexico City Metropolitan Area and other surrounding cities. Nutrient loading to this reservoir increased 276% for phosphorus (P) and 203% for nitrogen (N) in a single decade. During 2002-2005, P and N mean loadings to VB were 120.8 103 kg P/y and 591.8 103 kg N/y. These loadings were quite variable because of source variations from uncontrolled domestic and agricultural inputs. More than half (56%) of the maximal water storage of the reservoir was withdrawn annually. Water withdrawal removed 22% of the P input. Comparative examination of P and N mass balances showed that most (85%) of the P input to VB accumulates in the sediments. Despite the hypolimnetic anoxia that VB exhibits from March to October, net P accumulation in the sediments is normally observed. Our results confirm that although VB behaves as a warm monomictic water body, its mean hypolimnetic temperature increases throughout the stratification period. Nitrogen limitation was indicated by the dissolved inorganic nitrogen (DIN) to total dissolved P (DIN:TDP = 8.3, molar) ratio during stratification periods. We estimated that N2 fixation exceeded denitrification. This net fixation could double the N loading from rivers and sewage. Management recommendations include (a) gauging of river and sewage inputs to VB, (b) reduction of P input through treatment of sewage from VB town and (c) monitoring and regulating fertilizers and other nonpoint source inputs in the Amanalco watershed. Valle de Bravo reservoir is similar to other eutrophic tropical lakes and reservoirs that could also improve their water quality through these management practices. |
| Abundance and habitat use of juvenile sunfish among different macrophyte stands | Paris D. Collingsworth; Christopher C. Kohler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 1 | 2010 | 35 - 42 | Abundance and habitat use of juvenile sunfish among different macrophyte stands | Collingsworth, PD and Kohler, CC. 2010. Abundance and habitat use of juvenile sunfish among different macrophyte stands. Lake Reserv. Manage. 26:35-42. Juvenile Lepomis sunfish (< 75 mm total length, TL) density, plant stem density and invertebrate density were compared in the 3 most common habitats in the littoral zone of Cedar Lake, a Midwestern North American reservoir: nonvegetated areas, stands of the exotic macrophyte Eurasian watermilfoil (Myriophyllum spicatum) and stands of American pondweed (Potomogeton nodosus). Eurasian watermilfoil stands consistently had significantly higher stem density and invertebrate density than American pondweed stands. Juvenile sunfish densities were significantly higher in vegetated habitats than nonvegetated areas, but no significant differences were observed between the 2 vegetated habitats. Juvenile sunfish densities were initially higher in American pondweed stands than Eurasian watermilfoil stands, but fish density in American pondweed stands declined dramatically as water levels fell in autumn. Juvenile sunfish size structure was related to habitat type, with the smallest fish associated with Eurasian watermilfoil (38.2 mm TL), intermediate fish associated with American pondweed (43.1 mm TL), and the largest fish associated with nonvegetated habitats (51.2 mm TL). We suggest resource agencies should focus vegetation management efforts on eradicating Eurasian watermilfoil stands to provide foraging access for largemouth bass to improve their growth rate and reduce stunting of sunfish. However, management agencies must recognize that a healthy plant community below the depth of water level fluctuation may be the only source of cover for juvenile centrarchids during late summer in reservoirs prone to fluctuating water levels. |
| Influence of pumped-storage hydroelectric plant operation on a shallow polymictic lake: Predictions from 3-D hydrodynamic modeling | Michael A. Anderson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 1 | 2010 | 1-13 | Influence of pumped-storage hydroelectric plant operation on a shallow polymictic lake: Predictions from 3-D hydrodynamic modeling | Pumped-storage hydroelectric plants play important roles in electrical supply grids by providing electricity during periods of peak demand, storing renewable energy and controlling supply frequency. The pumping of water from a lower lake or reservoir to an upper impoundment and the return of that water during power generation can strongly affect the properties of pumped-storage reservoirs, however. For example, plant operation has been found to delay, weaken or eliminate thermal stratification, resuspend bottom sediments and entrain organisms. The aim of this study was to better understand the impacts of a proposed pumped-storage facility on stratification, mixing and sediment resuspension in Lake Elsinore, a shallow, polymictic lake in southern California. Three-dimensional hydrodynamic simulations were conducted using the Environmental Fluid Dynamics Code (EFDC). Model simulations demonstrated regular variations in the lake surface elevation of 0.24-0.5 m associated with pumping and generation, although a large shore-mounted intake structure resulted in quite low velocities near the intake (< 6 cm/s), bottom shear values below the assumed critical threshold for resuspension (< 0.1 N/m2), and limited overall effect on stratification and mixing in the lake. Entrainment of larval fish and other planktonic organisms remains a concern, however. |
| Testing a methodology for assessing plant communities in temperate inland lakes | Alison Mikulyuk; Jennifer Hauxwell; Paul Rasmussen; Susan Knight; Kelly I. Wagner; Michelle E. Nault; Daryl Ridgely | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 1 | 2010 | 54 - 62 | Testing a methodology for assessing plant communities in temperate inland lakes | We outline and test an aquatic plant sampling methodology designed to track changes in and make comparisons among lake plant communities over time. The method employs a systematic grid-based point-intercept sampling design with sampling resolution adjusted based on littoral area and lake shape. We applied this method in 72 Wisconsin lakes ranging from 6.5-245 ha in size, recording species presence-absence and depth at approximately 20,000 unique sample points. To assess how reductions in sampling effort might affect data quality, we used Monte Carlo simulations (100 iterations at each of 9 levels of sampling intensity) to reduce total lake sample points by 10% through 90% using a stratified random selection approach. Species accumulation curves were fit using the Michaelis-Menten 2-parameter formula for a hyperbola, and the predicted asymptote was similar to observed species richness. In a subset of lakes, oversampling (200% effort) did not yield significant increases in species richness. However, even a modest reduction (10-20%) in sampling effort affected species richness, while frequencies of occurrence of dominant species and estimations of percent littoral area and maximum depth of plant growth were less sensitive to sampling effort. In addition, we provide results of a power analysis for detecting changes in plant communities over time. Future applications of this protocol will provide information suitable for in-lake management and for assessing patterns in aquatic plant communities state-wide related to geographic region, hydrological characteristics, land use, invasive species and climate. |
| Assessing variability in total phosphorus measurements in Ontario lakes | Bev J. Clark; Andrew M. Paterson; Adam Jeziorski; Susan Kelsey | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 1 | 2010 | 63 - 72 | Assessing variability in total phosphorus measurements in Ontario lakes | In most Ontario lakes, phosphorus is present in trace quantities, making the precise measurement of concentrations difficult. The considerable variation that results in many datasets can be attributed to imprecise analysis. Even with precise analysis, substantial variation in ice-free whole-lake, mean mixed layer, and spring turnover total phosphorus (TP) concentrations often remain, both between years and within a given year. Lake managers have adopted many strategies to address these issues. Whole-lake TP concentrations expressed as ice-free season means are difficult to derive because they require the collection of numerous, volume-weighted samples often from multiple lake layers. As a result, spring turnover or ice-free-mean, mixed layer TP concentrations are often used to characterize the trophic status of a lake or to describe the nutrients available for primary production. These different phosphorus characterizations will vary between years, leading many lake managers to use long-term (multiple year) means to describe trophic status. The ability to interpret natural variation or trends in these data can be reduced by any bias introduced through sample collection and storage (container) methods or as a result of sample contamination by zooplankton, which can produce high sample TP concentrations. Much variability can be reduced through precise analysis, and most sources of error can be eliminated by sampling directly into the same borosilicate glass tubes used to digest samples prior to analysis and by coarse filtering water samples in situ to 80 μ m to eliminate large zooplankton. We demonstrated the importance of collecting precise TP data and presented the variation associated with 25 years of TP measurements in Ontario, Precambrian Shield lakes. We also demonstrated various sample collection strategies that can be used to characterize the nutrient status of lakes and explained how the interpretation of these can be affected by variability in the results. |
| Common carp (Cyprinus carpio), sport fishes, and water quality: Ecological thresholds in agriculturally eutrophic lakes | Zachary J. Jackson; Michael C. Quist; John A. Downing; Joseph G. Larscheid | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 1 | 2010 | 14 - 22 | Common carp (Cyprinus carpio), sport fishes, and water quality: Ecological thresholds in agriculturally eutrophic lakes | We examined fish populations, limnological conditions, lake basin morphology and watershed characteristics to evaluate patterns in population characteristics of ecologically important fish species in relation to environmental conditions in agriculturally eutrophic lake systems. Fish populations and environmental characteristics were sampled from 129 Iowa lakes using standard techniques from 2001-2006. Lakes with high catch rates of common carp (Cyprinus carpio) had high nutrient concentrations, high phytoplankton biomass and low water transparency. In addition, lakes with high catch rates of common carp had low catch rates of important sport fishes including bluegill (Lepomis macrochirus), largemouth bass (Micropterus salmoides), black crappie (Pomoxis nigromaculatus) and white crappie (P. annularis). The relationship between common carp and sport fishes appeared to function as an ecological threshold. Specifically, when common carp catch rates were > 2 kilograms per fyke net night, catch rates of sport fish were always low and water quality in the study lakes was poor. Shallow systems (natural lakes, oxbows) had higher densities of common carp compared to deeper systems (impoundments, surface mines), thereby suggesting that shallow lakes are most sensitive to the effects of common carp and that restoration efforts incorporating biomanipulation of common carp will likely be most successful in shallow systems. |
| A retrospective analysis of suspended solids deposition in Onondaga Lake, New York: Composition, temporal patterns, and drivers | Craig A. Hurteau; David A. Matthews; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 26 | 1 | 2010 | 43 - 53 | A retrospective analysis of suspended solids deposition in Onondaga Lake, New York: Composition, temporal patterns, and drivers | Hurteau CA, Matthews DA, Effler SW. 2010. A retrospective analysis of suspended solids deposition in Onondaga Lake, New York: Composition, temporal patterns, and drivers. Lake Reserv. Manage. 26:43-53. Long-term and seasonal temporal patterns in the deposition of total (TSS), fixed (FSS) and volatile suspended solids (VSS) were documented for eutrophic Ca2 +-rich Onondaga Lake, New York, for the 1980-2008 interval. Weekly collections were made from sediment traps deployed below the thermocline from April to October in the deepest area of the lake (19.5 m). Downward fluxes of TSS (DFTSS), FSS (DFFSS) and VSS (DFVSS) decreased 42, 38, and 41%, respectively, following closure of a soda ash facility in 1986 that discharged ionic waste to the lake. The DFTSS decreased 47% from 2007 to 2008, driven mostly by lower CaCO3 deposition. Sediment accumulation rates derived from dry weight deposition were estimated to decrease from 0.8 cm/yr during 1980-1986 to 0.4 cm/yr during 1987-2007 to 0.2 cm/yr in 2008. On average, DFCaCO3 accounted for 83% of DFFSS and 69% of DFTSS. The event-like character observed for DFFSS was attributed to variations in CaCO3 precipitation, probably driven by variations in temperature, pH and the availability of nucleation sites. The DFVSS decreased 56% from 2.5 g/m2 · d to 1.1 g/m2 · d over the 1989 to 2008 interval. Decreased phosphorus loading from a municipal wastewater treatment facility explained 67% of the interannual variations in DFVSS. Weekly variations in the DFVSS were generally correlated with chlorophyll levels in the upper waters, and maximum values were observed during major phytoplankton blooms. Seasonal minima of DFVSS and DFFSS occurred during clear water phases, associated with Daphnia grazing, which were observed annually from 1987 to 2002, and again in 2008. Changes in primary production and lake chemistry could have significant effects on the burial of contaminants and microbial metabolism in the sediments. |
| Phosphorus balance of Lake Tiefwarensee during and after restoration by hypolimnetic treatment with aluminum and calcium salts | Gerlinde Wauer; Thomas Gonsiorczyk; Michael Hupfer; Rainer Koschel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 4 | 2009 | 377 - 388 | Phosphorus balance of Lake Tiefwarensee during and after restoration by hypolimnetic treatment with aluminum and calcium salts | Between 2001 and 2005, the recovery of Lake Tiefwarensee from eutrophic to mesotrophic state was successfully accelerated by the stepwise hypolimnetic addition of 137 g aluminum and 154 g calcium per square meter of profundal sediment. In response to the treatment, an 8-cm sediment cover was formed, which almost completely suppressed the phosphorus (P) release from the sediments, and is still present. The spatial variability of the sediments was analyzed at eight sampling points at different lake depths. With increasing lake depth, soluble reactive phosphorus decreased in the pore water, whereas the total phosphorus (TP) increased in treated sediment. Total P in the upper sediment layer (0-10 cm) increased by about 3 tons during the treatment period, consistent with the simultaneous decrease in the water from 0.223 mg/L in 1998 to 0.013 mg/L in 2005 (annual mean values for the whole water body). After initial settling, the drastic TP decrease in the water column can be attributed to an increase in the sediment P-binding capacity, which is related to a decrease of the mobile P pool (NH4Cl-TP) and a strong increase in the Al:P ratio in sediment. In the 3 years after completion of the treatment, the lake TP concentration was well described by the Vollenweider model, indicating that a sustainable state of nutrient equilibrium was achieved. |
| Ecological classification of a set of Mediterranean reservoirs applying the EU Water Framework Directive: A reasonable compromise between science and management | E. Navarro; L. Caputo; R. Marcé; J. Carol; L. Benejam; E. GarcÃa-Berthou; J. Armengol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 4 | 2009 | 364 - 376 | Ecological classification of a set of Mediterranean reservoirs applying the EU Water Framework Directive: A reasonable compromise between science and management | The Water Framework Directive EU2000/60/EC (WFD) was implemented for reservoirs at a regional scale (northeastern Spain). Twenty-one reservoirs were monitored quarterly over the course of a year. Using principal component analysis, the reservoirs were classified into types according to their geological and morphometric features. The Ecological Quality (EQ) of the reservoirs was assessed by integrating values of total chlorophyll a, cyanophyta chlorophyll a concentration, fish metrics, Secchi depth, averaged hypolimnetic oxygen concentration and total phosphorus. For each reservoir type, a reference condition of quality was selected. When possible, this reference was the reservoir displaying the best EQ; otherwise expert judgment was used. To allow comparison of quality among reservoirs belonging to different types, thus identifying intrinsic differences, an Ecological Quality Ratio (EQR) was calculated by dividing the EQ value of each reservoir by that of its reference. According to EQR, the majority of the reservoirs accomplished the quality criteria of the WFD. This study identified a number of useful indicators for EQ assessment. Moreover, because the references were chosen among similar reservoirs, low EQR values are indicative of specific problems, such as untreated or wastewater spills or droughts. The results also demonstrate that expert judgment is a reasonable compromise when the low number of water bodies available for the study prevents statistical approaches. |
| Newman Lake restoration: A case study. Part I. Chemical and biological responses to phosphorus control | Barry C. Moore; David Christensen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 4 | 2009 | 337 - 350 | Newman Lake restoration: A case study. Part I. Chemical and biological responses to phosphorus control | In the late 1960s and early 1970s, summer and fall blooms of cyanobacteria began to occur in Newman Lake, Washington (zavg: 5.6 m, zmax: 9.0 m); through the next decade, these blooms intensified and became an annual occurrence. Community efforts in the mid-1980s sparked a Restoration Feasibility assessment of the lake and watershed that indicated total annual gross phosphorus loading of at least 3000 kg, with a major portion (∼83%) attributable to internal recycling associated with summer hypolimnetic oxygen depletion. Implementation activities began September 1989, with watershed controls and a whole-lake alum treatment, followed in 1992 by installation of a Speece cone for hypolimnetic oxygenation and in 1997 by addition of a dual-port, microfloc alum injection system. Average summer volume-weighted total phosphorus has declined from prerestoration levels exceeding 50 μg-P/L to an average of 21 μg-P/L over the past 7 years (15-28 μg-P/L). Most notably, peak annual biovolumes of cyanobacteria and their representation within the phytoplankton community have decreased substantially, with increased prevalence of diatoms, green and golden-brown algae. A clearwater phase following spring blooms of diatom and/or golden-brown algae has occurred during those last 7 years, although this phenomenon was observed in the prior three decades. Overall, the restoration has been a success, and lake response to nutrient reduction at Newman Lake is consistent with worldwide observations that emphasize the need for long-term perspectives and commitment in lake restoration and management. Continuation of internal load controls and increased emphasis on external nutrient abatement will be necessary to continue the positive water quality trends despite future development increases and land use changes. |
| Newman Lake restoration: A case study. Part II. Microfloc alum injection | Barry C. Moore; David Christensen; Ann C. Richter | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 4 | 2009 | 351 - 363 | Newman Lake restoration: A case study. Part II. Microfloc alum injection | Microfloc alum injection, in contrast to whole-lake alum treatments, is a relatively new technique for alum delivery that has been implemented in a relatively small number of lakes and reservoirs. Microfloc alum injection is primarily designed to precipitate phosphorus in the water column using low doses applied on a continuous or intermittent basis. The technique employs diffusers to create ultra-small aluminum hydroxide particles with lower settling velocities and longer residence times, compared to whole lake treatments, to strip dissolved phosphorus from the water column. Because relatively few microfloc systems have been deployed, a brief review of their characteristics and performance is provided. In Newman Lake, Washington, a microfloc alum injection system has been in use since spring 1997. We tested microfloc residence times using in situ enclosures; residence time was determined to be at least 10 days, supporting the underlying concept. In the lake itself, turnover events prior to alum injection consistently produced higher algae growth with accompanying lower Secchi transparency. Since alum injection, post-turnover Secchi depths have all improved. In 18 years with 32 monitored turnover events, this relatively robust dataset consistently indicates the short-term ability of microfloc to improve transparency through algae reduction. Volume-weighted total phosphorus concentrations also have generally declined following alum injection. Adverse biological impacts were not observed in either enclosures or the lake. In the enclosure studies, total zooplankton and cladoceran densities and biomass in treatments were not significantly different from controls. Further applications and study of this promising technology are warranted. |
| Phosphorus forms in urban and agricultural runoff: Implications for management of Danish Lake Nordborg | Sara Egemose; Henning S. Jensen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 4 | 2009 | 410 - 418 | Phosphorus forms in urban and agricultural runoff: Implications for management of Danish Lake Nordborg | The catchment of eutrophic Lake Nordborg, Denmark, consists of 25% urban areas with separate sewer systems and 63% agricultural areas with clayey soil and grain crops. Diffuse runoff is the only external phosphorus (P) source (∼ 550 kg/yr), but the lake suffers from high internal loading (∼ 1300 kg/yr). In-lake aluminum treatment is suggested if external P-loading can be brought down by ∼ 30% to an annual average inlet concentration of < 0.100 mg/L. We examined the share and bioavailability of particulate P (PP) in 14 tributaries during a winter season to evaluate if the reduction in bioavailable P-load can be obtained by construction of precipitation/retention ponds in major inlets. One-third of the P-load occurred as PP, independent of catchment type. For urban runoff, 62% of PP was surface adsorbed P, iron-bound P, and extractable organic P, all of which may be considered bioavailable. The corresponding value for agricultural tributaries was 76%. For both types of catchments more than 70% of total P (PP and dissolved P) was bioavailable, but total concentrations were much higher (0.174 ± 0.032 mg/L) in agricultural runoff than in urban runoff (0.082 ± 0.019 mg/L). Measurements of PP settling velocity revealed that ∼ 30% settled slower than 1 cm/h whereas ∼ 50% settled faster than 1 m/h. Therefore, water retention time in precipitation ponds to Lake Nordborg should exceed 8 h to reach the target reduction in P-load. Focus should be on the agricultural catchment that contributes 140 kg to PP load, rather than the urban catchment that only contributes 48 kg. |
| Assessing internal phosphorus load - Problems to be solved | Gertrud K. Nürnberg | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 4 | 2009 | 419 - 432 | Assessing internal phosphorus load - Problems to be solved | Internal loading as phosphorus (P) released from anoxic sediment surfaces often represents the main summer P load to lakes and reservoirs and can have an immense effect on their water quality. Many difficulties in internal load assessment exist, however, including ignoring internal load altogether, ambiguity about the origin of sediment released P and inexact definitions. Most of these problems are due to the difficulty in distinguishing internal from external P sources, which is particularly challenging in polymictic lakes. To prevent misconceptions and facilitate its evaluation, internal load in stratified and polymictic lakes should be expressed in a similar way to external loads: as annual, gross and areal load of total phosphorus (TP). Possible approaches to internal load quantification are: in situ determination from hypolimnetic P increases, mass balance approaches, and estimates from anoxic active area and P release. Further suggestions to facilitate the study of internal loading include: (a) the differentiation between polymictic and stratified lakes, sections of lakes, and time periods when evaluating indicators and impact of internal load; (b) the separation of internal load (upward flux) from sedimentation (downward flux) of external and internal loads, and (c) the consideration of the downward flux of both external (Lext, mg/m2/yr) and internal (Lint, mg/m2/yr) loads by a retention model (Rsed) when predicting lake TP averages in a mass balance model of the form (qs = annual areal water load in m/yr): |
| Should nitrogen be reduced to manage eutrophication if it is growth limiting? Evidence from Moses Lake | Eugene B. Welch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 4 | 2009 | 401 - 409 | Should nitrogen be reduced to manage eutrophication if it is growth limiting? Evidence from Moses Lake | The recovery of Moses Lake from hypereutrophy to mesotrophy over a 25-year period resulted from the addition of large quantities of low nitrogen (N) and phosphorus (P) dilution water and a change in irrigation practices. Throughout the recovery, the in-lake ratio of nitrate-N to soluble reactive P (SRP) remained well below the Redfield ratio, indicating short-term N limitation. Nevertheless, the disproportionately greater reduction in inflow P than N, relative to the Redfield ratio, caused the long-term reduction of total P (TP), SRP and chlorophyll. Lake TN:TP ratios consistently remained slightly above the Redfield ratio, apparently through N fixation, despite continued N limitation. Cyanobacteria (primarily Aphanizomenon) dominated the plankton algae during the recovery period until the lake became mesotrophic and calculated net internal loading of P was undetectable. These results demonstrate that usually inflow P, not N, should be reduced to effect long-term recovery of eutrophic lakes, despite observed short-term limitation by N. |
| Nutrient fluxes across reaches and impoundments in two southeastern Michigan watersheds | Nathan S. Bosch; Thomas H. Johengen; J. David Allan; George W. Kling | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 4 | 2009 | 389 - 400 | Nutrient fluxes across reaches and impoundments in two southeastern Michigan watersheds | River systems with impoundments are expected to experience greater nutrient removal as a consequence of enhanced nitrogen (N) loss by denitrification, settling and burial of phosphorus (P), and longer residence times of water relative to a free-flowing river. We evaluated the magnitude of N and P removal across stream reaches and impoundments, including annual and seasonal trends, in two southeastern Michigan rivers that differ in their degree of impoundment and watershed land use patterns. All nutrient fraction concentrations remained statistically unchanged across stream reaches of 2-3 km in length, but dissolved oxygen and pH increased. Impoundment outlets exhibited increases in water temperature and decreases in conductivity, TP, TN, TDP, SRP, TDN, and NO3-N relative to inflowing water. A nutrient load mass balance showed that two connected impoundments removed 18 and 32% of the annual river loads of TN and TP, respectively. Removal rates were seasonably variable, with TP removal most pronounced during winter months when the impoundment received episodic high P loads. Conversely, TN removal was greatest during summer and autumn months when impoundments were stratified and water temperatures were elevated. Strong seasonal differences in N and P transport through the impoundments demonstrated the capacity of impoundments to dramatically alter the timing and stoichiometry of downstream nutrient export. These seasonal differences also highlight the need to consider the entire annual cycle when estimating surface water nutrient dynamics or designing management plans for nutrient abatement. |
| Managing the lakes of the Rotorua District, New Zealand | Noel Burns; John McIntosh; Paul Scholes | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 284 - 296 | Managing the lakes of the Rotorua District, New Zealand | In 2005, Burns, McIntosh and Scholes described strategies to manage the Rotorua Lakes using lake monitoring together with designated baseline Trophic Level Index values established for each lake. Continued monitoring has revealed that 9 of the 12 Rotorua Lakes have Trophic Level Index values in excess of their baseline values. Action Plans have been drawn up for the remediation of these damaged lakes that specify the excess nutrient loading to each lake and propose actions for the decrease of these loadings. Nutrient loading to various lakes has been decreased by upgrading waste treatment facilities, dosing tributary streams with alum, diverting an enriched tributary flow directly into the outflow channel of a lake, precipitating in-lake phosphorus with Phoslockâ„¢ and zeolite additions, and removal of macrophyte biomass from a lake and planting an artificial wetland at the entry point of a tributary to a lake. Where data are available, the results of these actions are explored. The similarities between the management system for the Rotorua lakes with the management systems used for two American and European lakes are described. |
| Reduced river phosphorus following implementation of a lawn fertilizer ordinance | John T. Lehman; Douglas W. Bell; Kahli E. McDonald | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 307 - 312 | Reduced river phosphorus following implementation of a lawn fertilizer ordinance | Statistical comparisons of 2008 surface water quality data with a historical data set at weekly and subweekly resolution revealed statistically significant reductions in total phosphorus (TP) and a trend of reduction in dissolved phosphorus following implementation of a municipal ordinance limiting the application of lawn fertilizers containing phosphorus. No reductions were seen at an upstream control river site not affected by the ordinance. Nontarget analytes including nitrate, silica and colored dissolved organic matter did not change systematically as did P. The data were analyzed in the context of a statistical model that characterized historical temporal variability and predicted the sampling effort needed to detect changes of specified magnitude. Expected changes of about 25% in monthly mean value were predicted to require weekly samples during the summer for only 1 or 2 years for TP; statistically significant reductions measured after 1 year averaged 28%, or about 5 kg P/day. The lawn fertilizer ordinance was only one component of broader efforts to reduce nonpoint source loading of P, however, so the magnitude of its role in the measured changes remains uncertain. |
| Phosphorus reduction by dilution and shift in fish species in Moses Lake, WA | Eugene B. Welch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 276 - 283 | Phosphorus reduction by dilution and shift in fish species in Moses Lake, WA | Water quality over most of the area of Moses Lake improved greatly over a 25-year period (1977-2001) due largely to the addition of large quantities of low-nutrient Columbia River water as well as changed irrigation practices and diversion of wastewater. The oligotrophication of Moses Lake from hypereutrophy to borderline mesotrophy was accompanied by a marked shift in fish populations, determined by creel census and biological surveys that included electrofishing and gill netting. The catch fraction of panfish (crappie and bluegills) decreased markedly; largemouth bass decreased to a lesser extent, while smallmouth bass, walleye and brown bullhead increased several-fold. These population shifts are consistent with observations elsewhere in response to oligotrophication and piscivory. |
| Partitioning phosphorus concentrations and loads in tributaries of a recovering urban lake | Steven W. Effler; Anthony R. Prestigiacomo; David A. Matthews; Edward M. Michalenko; Donald J. Hughes | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 225 - 239 | Partitioning phosphorus concentrations and loads in tributaries of a recovering urban lake | The partitioning of phosphorus (P) loading to culturally eutrophic lakes according to sources is fundamental information to guide rehabilitation programs and support mathematical models. Patterns of concentrations and loading rates of forms of P are documented for the major tributaries of Onondaga Lake, New York, United States, an urban lake that has recently demonstrated marked recovery from extreme cultural eutrophy as a result of decreased P loading from a domestic wastewater treatment plant (WWTP). This analysis is based on long-term (19 yr) biweekly monitoring of total, dissolved, and soluble reactive forms of P at the mouths of the three largest tributaries, and shorter-term higher frequency monitoring of one of the streams at two sites to resolve rural versus urban contributions. Signatures of anthropogenic sources were identified, including: (1) combined sewer overflows, (2) leaky sewers or other dry weather discharges, and (3) hydrogeologic sediment sources. On an annual average basis, the prevailing tributary and WWTP contributions to the total P load are approximately 70 and 30%, respectively. However, in terms of effective P loading, that which can be used to support primary production during the critical summer months, the tributaries contributed substantially less (∼35%) of the P load. Under the prevailing WWTP loading rate, reductions in tributary loading from aggressive tributary loading management efforts (e.g., 20-30% decrease) would not be expected to yield conspicuous improvements in related features of lake water quality. However, noteworthy improvements are a reasonable expectation from such tributary management efforts following the mandated further reductions in WWTP loading. |
| Blue-green algal toxin (microcystin) levels in Minnesota lakes | Matt Lindon; Steven Heiskary | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 240 - 252 | Blue-green algal toxin (microcystin) levels in Minnesota lakes | Increased interest in blue-green algal toxins in recent years has led to increased monitoring to assess occurrence and levels of toxins in Minnesota lakes. Microcystin (MC), a hepatotoxin, is one of the primary toxins studied in Minnesota and elsewhere in North America. The Minnesota Pollution Control Agency has measured MC in numerous lakes across Minnesota as a part of three separate efforts: (1) A targeted survey in 2006 to assess MC levels in 12 eutrophic lakes in two south central Minnesota counties; (2) A stratified-random survey of 50 lakes in Minnesota as a part of the National Lake Assessment Project; and (3) Incident-based samples from various lakes during 2004-2007 with reports of severe nuisance algal blooms, potential for human health risk and/or documented dog deaths as a result of algal toxins. This investigation focuses primarily on the 2006 study and linkages between MC and other chemical, physical and biological measures. Of 133 MC samples, 94% were above the Method Detection Limit (MDL = 0.15 ug/L). Based on World Health Organization guidelines, 80% of all MC samples ranked in the “low risk†category (<10 μg/L), 8% as “moderate risk†(>10-20 μg/L), 11% as “high risk†(20-2000 μg/L), with an overall maximum of 8400 μg/L. Microcystin exhibited significant positive correlations (Rs) with pH and chlorophyll-a and significant negative correlations with alkalinity and Secchi depth. Data from the other two efforts place the 2006 results in perspective and provide a comprehensive representation of MC concentrations in Minnesota lakes and an improved basis for communicating risk to the public. |
| Microcystin in Missouri reservoirs | Jennifer L. Graham; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 253 - 263 | Microcystin in Missouri reservoirs | During summers (May-Aug) 2004-2006, 177 Missouri reservoirs were sampled monthly at open pelagic locations to assess regional patterns in microcystin concentration, frequency of occurrence over successive summer seasons and relations with environmental factors. Microcystin was detected in 58% of Missouri reservoirs and 23% of samples (n = 1402). Total microcystin concentrations, measured by enzyme-linked immunosorbent assay, ranged from ≤ 0.1 to 21 μg/L. Concentrations ≥ 1 μg/L were detected in 10% of reservoirs and exceeded the human health concern limit of 20 μg/L once in a single sample. Microcystin occurred throughout summer, with maximum concentrations in individual reservoirs observed in each month. Occurrence was consistent across years, with about one-half of Missouri reservoirs having detectable microcystin each summer. Eleven reservoirs with microcystin maxima ≥1 μg/L were sampled multiple seasons; of these, 8 had detectable microcystin each summer, which indicates that short-term surveys can identify water bodies with the greatest potential for toxin production. Eutrophic reservoirs in northern Missouri had the greatest microcystin occurrence and concentrations. Reservoirs with detectable microcystin had significantly (p < 0.01) greater nutrient and chlorophyll values and significantly shallower Secchi depths than reservoirs without detection. All correlations, however, had r-values ≤ 0.35, and bivariate plots indicated nonlinear trends. Cylindrospermopsin was measured by enzyme-linked immunosorbent assay in 36 reservoirs once in late summer 2006; 14% had small detectable levels (total concentrations < 1 μg/L). This is the first report of cylindrospermopsin in Missouri. |
| Survey of toxic algal (microcystin) distribution in Florida lakes | D. L. Bigham; M. V. Hoyer; D. E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 264 - 275 | Survey of toxic algal (microcystin) distribution in Florida lakes | A survey of microcystin in 187 Florida lakes was completed from Jan to Dec 2006. Annual average microcystin concentrations of the 187 Florida lakes ranged from nondetectable (< 0.1 μ g/L) to 12 μ g/L, with concentrations in individual water samples (N = 862) ranging from nondetectable to 32 μ g/L. Only 7% of all the individual samples exceeded the World Health Organization (WHO) drinking guidance value of 1 μ g/L. Three individual water samples collected from two lakes (0.3%) exceeded the WHO recreational guidance value of 20 μ g/L. Using chlorophyll concentrations and Secchi depth measurements, tables were constructed to predict the probability that microcystin concentrations exceeded the WHO guidance values in Florida lakes. Additionally, six hypereutrophic lakes (Harris Chain of Lakes, Lake County, FL) were studied from Sep 2006 to Aug 2007 and 40% of the samples exceeded 1 μ g/L but none exceeded 20 μ g/L. This study also provides baseline information and relations between trophic status, seasonality, water chemistry and microcystin concentrations in Florida lakes. |
| A Review of “Environmental Best Management Practices for Aquaculture†| Craig S. Tucker and John A. F. Hargreaves, eds. First edition 2008. Blackwell Publishing. ISBN-13: 978-0-8138-2027-9. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 336 | A Review of “Environmental Best Management Practices for Aquaculture†| |
| Factors contributing to cucumber odor in a northern USA reservoir | Lauren A. Schroeder; Scott C. Martin; Amulya Poudel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 323 - 335 | Factors contributing to cucumber odor in a northern USA reservoir | Episodic occurrences of cucumber odor caused by the alga Synura petersenii in Meander Creek Reservoir (MCR), northeastern Ohio, USA, are partly attributed to increased water transparency resulting from decreased phosphorus and suspended solids loading from the watershed. The first documented occurrence of nuisance odor levels was in 1984, 52 years after the reservoir was filled. This indicates that previous environmental factors constraining the growth of S. petersenii have been relaxed, probably from changes in the physical-chemical environment in the reservoir caused by changes in land use in the catchment. Reduction in farming since 1950, and diversion of sewage around the reservoir in 1977, reduced suspended solids and total phosphorus loading into the reservoir during the time that the cucumber odors occurred. These observations support the hypothesis that increased transparency of the reservoir, resulting from decreased sediment loading and reduced productivity, has permitted the occasional occurrence of nuisance densities of S. petersenii. Based on available data, pH, iron, and silica do not appear to be key factors regulating growth of S. petersenii in MCR. The transition to lower turbidity and total phosphorus concentrations from catchment restoration actions may increases the risk of S. petersenii blooms and cucumber odor episodes. While the overall benefits of cleaner raw water for water supply may outweigh this risk, it is desirable to understand the factors that promote nuisance growths and take actions to control them. |
| Assessing hypolimnetic oxygen concentrations in Canadian Shield lakes: Deriving management benchmarks using two methods | A. M. Paterson; R. Quinlan; B. J. Clark; J. P. Smol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 313 - 322 | Assessing hypolimnetic oxygen concentrations in Canadian Shield lakes: Deriving management benchmarks using two methods | The ability to predict hypolimnetic dissolved oxygen concentrations in lakes and to track changes in concentrations over time in response to known environmental stressors is critical for effective lake management. The background concentrations of deepwater oxygen, in particular, provide important management benchmarks for assessing the impact of current and future shoreline residential development on water quality. Background can be defined as the conditions that exist in the absence of, or prior to, human influence. We compare 2 models commonly used to predict end-of-summer, volume-weighted hypolimnetic oxygen (VWHO) concentrations in Canadian Shield lakes. The paleoecological and empirical models are evaluated in their ability to predict present-day VWHO concentrations, and then compared in their predictions of background VWHO concentrations and in predictions of changes in VWHO from background to present-day conditions. The predictive power of the 59-lake paleoecological model (jackknifed r2 = 0.51, RMSEP = 2.18 mg/L) is comparable to other models that have used chironomids to predict the degree of hypolimnetic anoxia in lakes but is lower than that produced by the empirical modelling approach (r2 = 0.87, SE = 1.04 mg/L). However, this discrepancy may be offset by the enhanced realism of the paleoecological model, including its ability to predict declines in VWHO over time. The combined use of the paleoecological and empirical modelling approaches may allow lake managers to examine changes in deepwater oxygen concentrations in response to a single “targeted†stressor (e.g., residential shoreline development) and to multiple environmental stressors (e.g., climate change, hydrological management). |
| Using numerical models and acoustic methods to predict reservoir sedimentation | Şebnem Elçi; Aslı Bor; Anıl Çalışkan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 3 | 2009 | 297 - 306 | Using numerical models and acoustic methods to predict reservoir sedimentation | This study draws on drainage basin hydrography, numerical modeling and geographic information system (GIS) techniques in concert with dual frequency echo sounder data to estimate sediment thickness when initial surveys are unavailable or inaccurate. Tahtali Reservoir (Turkey), which provides 40% of water supply to the city of Izmir, was selected as the study site. Deposition patterns within the whole lake were estimated with a 3-D hydrodynamic and sediment transport model applied to Tahtali Reservoir. The numerical model simulated lake response to wind forcing and inflows and/or outflows and was used to describe sediment deposition patterns resulting from the erosion of soils quantified by the implementation of Universal Soil Loss Equation (USLE) to the whole watershed. Surveying of the lake via dual frequency (28/200 kHz) echo sounder system revealed the current bathymetry, and sediment thickness was estimated from the difference of depths measured by the dual frequency sounder along surveyed transects. These results were compared to the modeled sedimentation thicknesses and to preliminary estimates of watershed sediment yield estimated by USLE. Results of this study can be used for further water quality studies and for long term management plans. |
| Trophic status of three large Missouri River reservoirs | David W. Bolgrien; Jill V. Scharold; Ted R. Angradi; Tim D. Corry; E. William Schwieger; John R. Kelly | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 176 - 190 | Trophic status of three large Missouri River reservoirs | Bolgrien, D.W., J.V. Scharold, T.R. Angradi, T.D. Corry, E.W. Schwieger and J.R. Kelly. 2009. Trophic status of three large Missouri River reservoirs. Lake Reserv. Manage. 25:176-190. Probability-based surveys conducted between 2001-2004 characterized the three large reservoirs of the Missouri River—Lake Oahe, Lake Sakakawea, and Fort Peck Lake—as mesotrophic to eutrophic, phosphorus (P) limited, and generally supporting cold water habitat (bottom waters <15°C and dissolved oxygen [DO] concentrations >5 mg/L) in midsummer. Riverine zones were shallower, warmer, more eutrophic, and had lower DO and higher suspended matter concentrations than lacustrine zones. Similar, although more variable, differences were found between bays and open-water areas. Between sampling years, water levels decreased in each reservoir. In the first year of sampling, area-weighted mean reservoir trophic status index based on chlorophyll (TSIchl) was about 37 in all three reservoirs. Sixty percent of Oahe and Sakakawea and 40% of Fort Peck had TSIchl> 50. Trophic status index based on Secchi depth (TSISD) averaged about 50 in each reservoir across years. Because mean TSIchl< TSISD, light attenuation was considered to be silt, not algae, dominated. Trophic status index based on total P (TSITP) and the ratio of N:P concentrations indicated that the reservoirs were very P limited. Mean bottom temperature and DO concentration in Oahe were unchanged between years at about 19°C and 7.5 mg/L, respectively. Bottom temperatures in Sakakawea increased (from 15°C to 21°C) and DO concentration decreased (from 7.3 mg/L to 6.0 mg/L) with lower water levels. In Fort Peck, bottom temperature remained about 18°C, but DO concentration fell from 7.23 mg/L to 4.96 mg/L. Results show that surveys successfully characterized important environmental conditions throughout these large reservoirs. |
| Water-level observations of Lake Weishan-Zhaoyang-Nanyang in China during 1814∼1902 AD | Jie Fei | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 131 - 135 | Water-level observations of Lake Weishan-Zhaoyang-Nanyang in China during 1814∼1902 AD | Fei, J. 2009. Water-level observations of Lake Weishan-Zhaoyang-Nanyang in China during 1814 ∼ 1902 AD. This article reports the evaluation and preliminary interpretation of the monthly water-level observations of Lake Weishan-Zhaoyang-Nanyang (WZN) in east China during 1814∼1902 AD. Observations were conducted by the government. According to the extant historical literature, the gaps in observations for this time period are 13.2%, 24.9%, and 24.5%, respectively, for the three parts of the lake: Weishan, Zhaoyang, and Nanyang. After a preliminary interpretation, we suggest that a correspondence exists between the high water-level years of Lake WZN and the flood years of the Yellow River during 1814∼1902 AD. |
| Development and application of a WASP model on a large Texas reservoir to assess eutrophication control | Mark R. Ernst; Jennifer Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 136 - 148 | Development and application of a WASP model on a large Texas reservoir to assess eutrophication control | Ernst, M.R. and J. Owens. 2009. Development and application of aWASP model on a large Texas reservoir to assess eutrophication control. The Tarrant Regional Water District developed and calibrated an 11-yr WASP-Eutro model for Cedar Creek Reservoir, a 13,350 ha (33,000 ac) drinking water supply and recreation reservoir located near Fort Worth, Texas, that is experiencing eutrophication. Cedar Creek was partitioned into 22 segments with up to three vertical segments in the main pool. Loading to the reservoir was divided into four categories: (1) watershed, (2) nine wastewater treatment plants (5.6 mgd), (3) atmospheric loading, and (4) internal NH4 and OPO4 sediment flux. Watershed loading was derived from a SWAT model of the 1007 mi2 watershed. Wastewater treatment plant loading was based on 1 yr of weekly plant nutrient and flow data. Atmospheric loading was estimated from periodic rain sampling adjacent to the reservoir. Internal flux was estimated from hypolimnetic accumulation during stratification. Calibration was judged by conformity of median observed and predicted water quality data and longitudinal profiles in the reservoir. Sensitivity analysis of these four loadings revealed that Chla and total phosphorus were most influenced by the watershed nonpoint source load. Internal flux was the next most influential load; form, timing and location of loading are more important than actual magnitude of this load. Estimates of the nonpoint source reduction necessary for a significant reduction in Chla were about 30%, while estimates of reductions in OPO4 flux to significantly reduce Chla were 75-100%. A combination of watershed and internal nutrient control are needed to control eutrophication in Cedar Creek Reservoir. |
| Factors affecting water willow establishment in a large reservoir | Paris D. Collingsworth; Ryan A. Oster; Christopher W. Hickey; Roy C. Heidinger; Christopher C. Kohler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 191 - 198 | Factors affecting water willow establishment in a large reservoir | Collingsworth, P.D., R.A. Oster, C.W. Hickey, R.C. Heidinger and C.C. Kohler. 2009. Factors affecting water willow establishment in a large reservoir. Lake Reserv. Manage. 25:200-207. We evaluated the transplanting potential of an emergent macrophyte, water willow (Justicia americana), into Rend Lake, a large, relatively unvegetated reservoir in southern Illinois. We transplanted water willow over two years into sites varying in physical conditions and using four propagule types. Transplanting in 2001 was performed to compare the durability of root crowns, plugs, and stem fragments, as well as to measure the effect of open water versus backwater sites on water willow survival. Water willow was transplanted in 2002 to explore how different planting protocols, such as planting in different months, planting different propagule types, and shoreline slope affect water willow survival. We found that water willow transplanted early in the summer had better post-winter colony survival and vigor (stem density within colonies) than transplants conducted later in the summer (Kruskal-Wallis test; P = 0.017). Rooted propagules had significantly greater first-year colony survival and ultimately exhibited greater vigor in newly established colonies. Lastly, we found that shoreline slope had a significant influence on the vigor of colonies following winter dormancy but was not significantly related to first-year colony vigor. In the summer following their initial transplanting, established water willow colonies planted on shorelines with steeper slopes (>5°) produced more plants than those planted on shallower shorelines (Kruskal-Wallis test; P = 0.003). Water willow seems to have high potential as a transplant species for reservoir management and riparian zone enhancement. |
| Effect of aquatic macrophytes on the survival of Escherichia coli in a laboratory microcosm | Gregory Kleinheinz; Amy Coenan; Tabitha Zehms; Justine Preedit; Mary-Catherine Leewis; Donna Becker; Colleen McDermott | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 149 - 154 | Effect of aquatic macrophytes on the survival of Escherichia coli in a laboratory microcosm | Kleinheinz, G., A. Coenan, T. Zehms, J. Preedit, M.C. Leewis, D. Becker and C. McDermott. 2009. Effect of aquatic macrophytes on the survival of Escherichia coli in a laboratory microcosm. Recreational beaches are very important as engines for tourism revenue in many areas of Wisconsin, United States, and microbial contamination of beach water can be very costly. Escherichia coli (E. coli) is the indicator organisms used in the Great Lakes region of the United States for recreational water monitoring. The overall objective of this study was to determine if aquatic macrophytes (Sagittaria sp., Myriophyllum sp.) allow for prolonged E. coli survival in the environment by using a laboratory microcosm as a test system. This study tested whether E. coli survival was greater in lake water alone or in lake water containing a high density of macrophytes (HDM), a low density of macrophytes (LDM), or plastic plant material. Water and plant substrate samples were analyzed for E. coli concentrations. ANOVA analysis indicated a significant difference between all treatments (p < 0.001). The Scheffe test revealed a significant difference between E. coli concentrations in water in the HDM treatment and the plastic plants (p = 0.003) and the controls (lake water only; p < 0.001), as well as differences between the LDM treatments and the plastic plants (p < 0.001) and the controls (p < 0.001). Attachment of E. coli to the macrophytes was rapid and may contribute to the rapid decline of E. coli found in the microcosm water samples. The presence of aquatic macrophytes did not appear to provide growth factors or other substances that could prolong the survival of E. coli in water, but the plants may contribute to bacterial survival by providing a medium for bacterial attachment. To our knowledge this is the first study reporting on the effects of aquatic macrophytes on E coli concentrations in water. |
| Using structural equation modeling and expert elicitation to select nutrient criteria variables for south-central Florida lakes | Melissa A. Kenney; George B. Arhonditsis; Linda C. Reiter; Matthew Barkley; Kenneth H. Reckhow | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 119 - 130 | Using structural equation modeling and expert elicitation to select nutrient criteria variables for south-central Florida lakes | Kenney, M.A., G.B. Arhonditsis, L.C. Reiter, M. Barkley, and K.H. Reckhow. 2009. Using structural equation modeling and expert elicitation to select nutrient criteria variables for south-central Florida lakes. To protect the nation's waterbodies from excessive impairments from pollution leading to eutrophication, the Clean Water Act requires states to establish water quality standards. These water quality standards are designed to protect the designated use, or water quality goal; however, they are indirectly measured and assessed using a water quality criterion. An alternative approach to develop nutrient criteria is the predictive approach (Reckhow et al. 2005), which determines the predictive variables by combining water quality data with assessments from multiple experts on the probability of designated use attainment using structural equation modeling (SEM). Our objective was to expand the predictive approach to include a region of waterbodies and to use multiple experts. To demonstrate these extensions, the approach was applied to lakes in south-central Florida using four experts to quantify attainment of a fish and wildlife designated use. Multiple models were built that related eutrophication processes to the designated use. Of the two plausible models, total phosphorus was the most predictive of the designated use followed by chlorophyll a. Using the model results, the risk of nonattainment of the designated use for these two predictive variables was calculated; to achieve high attainment (90% or more), total phosphorus should be < 0.015 mg/L and chlorophyll a < 5 μ g/L. This study provides vital extensions to the previous approach through its use of multiple experts and a region of lakes, making the approach applicable to other regions of waterbodies and conclusions useful to inform policy. |
| Shoreline stabilization using riprap breakwaters on a Midwestern reservoir | John P. Severson; Jack R. Nawrot; Mike W. Eichholz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 208 - 216 | Shoreline stabilization using riprap breakwaters on a Midwestern reservoir | Severson, J.P., J.R. Nawrot and M.W. Eichholz. 2009. Shoreline stabilization using riprap breakwaters on a Midwestern reservoir. Lake Reserv. Manage. 25:208-216. Shoreline erosion causes shoreline habitat loss and degradation and contributes to sedimentation, a major impairment in many lakes throughout the United States. Various shoreline stabilization techniques have been employed, but many are unsuccessful under high wave stress, do not contribute to shoreline habitat, or are too expensive to install on a large scale. Extensive erosion and lack of shoreline habitat on Kinkaid Lake in southern Illinois prompted lake managers to design and install riprap breakwaters to protect the littoral zone and bank as well as enhance habitat. The offshore breakwaters were shown to decrease wave height and associated erosion, allowing banks to start stabilizing and the protected littoral zone to begin sequestering sediment. Terrestrial area inside the protected zones was regressed against age since protection, bank height, and distance from bank to produce a terrestrialization predictive model. Vegetation richness was much greater at protected sites than unprotected sites, and vegetation cover increased with age since protection. The riprap breakwaters were successful at bank stabilization and habitat enhancement and should therefore be considered for use where these attributes are desired. |
| Relative influence of lake age and watershed land use on trophic state and water quality of artificial lakes in Kansas | Edward Carney | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 199 - 207 | Relative influence of lake age and watershed land use on trophic state and water quality of artificial lakes in Kansas | E. Carney. 2009. Relative influence of lake age and watershed land use on trophic state and water quality of artificial lakes in Kansas. Lake Reserv. Manage. 25:199-207. Eutrophication is an extensively documented concern for lake and reservoir management throughout the world. Eutrophication is also recognized as a naturally occurring process in both natural and artificial lakes, although it can be greatly augmented by human activities and is then referred to as “cultural eutrophication.†Unfortunately, natural process eutrophication is still sometimes used as a rationalization for not working toward the prevention or abatement of nutrient related pollution. Here, trophic state and other water quality data from a long-term (1975 to present) lake monitoring program were examined to determine the relative influences of watershed land use conditions and age in determining the trophic state conditions of artificial lakes in Kansas. The results indicate that age alone exerts very limited influence on eutrophication whereas watershed land use exerts an extreme, and often rapid, impact. Regardless of age, lakes within relatively unimpacted watersheds displayed trophic state conditions near regional reference conditions. Conversely, lakes within watersheds rich in human activities, regardless of water body age, tended toward greatly elevated trophic status. Eutrophication as a natural process is shown to be an invalid argument for ignoring excessive nutrient export from watersheds. |
| A Review of “Pollution of Lakes and Rivers: A Paleoenvironmental Perspective†| John P. Smol. Second Edition. 2008. Blackwell Publishing. ISBN: 978-1-4051-5913-5. 383 pages | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 224 | A Review of “Pollution of Lakes and Rivers: A Paleoenvironmental Perspective†| |
| Quantitative evaluation of water-level effects on “regeneration safe-sites†for lakeshore plants in Lake Kasumigaura, Japan | Jun Nishihiro; Izumi Washitani | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 217 - 223 | Quantitative evaluation of water-level effects on “regeneration safe-sites†for lakeshore plants in Lake Kasumigaura, Japan | Nishihiro, J. and I. Washitani. 2009. Quantitative evaluation of water-level effects on “regeneration safe-sites†for lakeshore plants in Lake Kasumigaura, Japan. Lake Reserv. Manage. 25:217-223. We evaluated the effects of water-level regime on the area of “regeneration safe-sites†for seed germination and initial establishment of seedlings of helophytes occurring in the emergent vegetation zone of Lake Kasumigaura, Japan. Based on the results of previous studies and an original experiment, potential regeneration safe-sites (PRS) for helophytes were defined as sites in which the ground surface was inundated for less than 3 consecutive days from 1 April to 15 May. We estimated and compared the areas of PRS both before and after the implementation of an artificial water-level regime in the mid-1970s. Comparisons were made using data on daily water levels during 1960-1969 and 1996-2005, topographic profiles of the lakeshore in 1967 and 2005, and areas of the emergent vegetation in 1972 and 1997. We estimated that the current area of PRS in the lake has been reduced to 24% of past levels. This reduction was accompanied by both a complete loss of a spring drawdown and a decrease in the area of emergent vegetation. The areas of PRS under various water management regimes indicated that a relatively slight lowering of the spring water level could cause a marked increase in the area of PRS (e.g., a 10-cm decrease in the managed target water level could result in a doubling of the area of PRS). Our results suggest a water-level management policy that includes a spring drawdown can be effective in the restoration of helophyte species diversity through the recovery of PRS. |
| Using stable isotopes and a multiple-source mixing model to evaluate fish dietary niches in a mesotrophic lake | David R. Christensen; Barry C. Moore | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 167 - 175 | Using stable isotopes and a multiple-source mixing model to evaluate fish dietary niches in a mesotrophic lake | Christensen, D.R. and B.C. Moore. 2009. Using stable isotopes and a multiple-source mixing model to evaluate fish dietary niches in a mesotrophic lake. Lake Reserv. Manage. 25:167-175. We used stable isotope analysis (SIA) of δ13C and δ15N and a multiple-source mixing model to evaluate dietary niches within the Twin Lakes, Washington, fish community to identify potential for exploitative competition, resource partitioning, and predation. The SIA revealed distinct spatial feeding niches; pelagic species were δ13C depleted, while littoral organisms were δ13C enriched. Trophic feeding niches were identified from δ15N enrichment with each successive trophic level. We found δ15N progression with increasing largemouth bass size, suggesting ontogenetic diet variability. Model results suggested that the smaller bass (i.e., ≤299 mm length) fed principally on golden shiner, crayfish, and macroinvertebrates while larger bass (≥300 mm) primarily consumed brook trout and golden shiner. Isotopic signatures for golden shiner were intermediary, indicating both pelagic and littoral feeding sources, including phantom midges (nocturnal and pelagic) and damselflies (littoral) as principal diet sources, suggesting possible horizontal diel migration in golden shiner. Pelagic zooplankton was indicated as the most important food source for rainbow trout. Food resources appeared to be partitioned among the Twin Lakes fish community, possibly limiting competitive interactions. Piscivory in largemouth bass was focused on golden shiner and brook trout, suggesting possible top-down regulation of lower trophic levels. Stable isotope analysis and multiple-source mixing models are useful tools that can improve lake and fishery management decisions by providing data on food web dynamics such as competition, resource partitioning, and predation in lakes. |
| Water quality assessment and ecoregional comparison of a reservoir in east-central Indiana | Jarmila PopoviÄová | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 2 | 2009 | 155 - 166 | Water quality assessment and ecoregional comparison of a reservoir in east-central Indiana | Popoviov, J. 2009. Water quality assessment and ecoregional comparison of a reservoir in east-central Indiana. Lake Reserv. Manage. 25:155-166. This study assessed water quality of a reservoir in an agricultural watershed of east-central Indiana, examined the effects of a thermal and oxygen regime on cycling of nutrients, and compared the results to ecoregional data and reference guidelines. Two locations were monitored biweekly from May through September 2007 for pH, temperature, dissolved oxygen, alkalinity, Secchi disk transparency (SD), chlorophyll a, and nutrient concentrations. The reservoir did not stratify during the monitoring season, although both anoxia and reoxygenation of the hypolimnion were observed. These conditions affected nitrogen (N) and phosphorus (P) cycling because nitrification was found to occur in the hypolimnion, and both internal load and water column mixing affected the concentrations and distribution of P. The reservoir was characterized as a eutrophic water body based on SD, total N and chlorophyll a concentrations, while total P concentrations classified the reservoir as slightly hypereutrophic (TSI = 73). This P overload has shifted the system toward N-limiting conditions (molar TN:TP = 18). Comparison of trophic parameters to Ecoregion 55 data placed this reservoir within the 75th percentile, and all parameters exceeded the U.S. Environmental Protection Agency ecoregional reference guidelines. I discuss a potential restoration of this water body to comply with the ecoregional nutrient criteria and to avoid future deterioration associated with N limitation. |
| Interactions between nitrogen dynamics and the phytoplankton community in Lake George, Florida, USA | Michael F. Piehler; Julianne Dyble; Pia H. Moisander; Andrew D. Chapman; John Hendrickson; Hans W. Paerl | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 1 - 14 | Interactions between nitrogen dynamics and the phytoplankton community in Lake George, Florida, USA | Piehler, M.F., J. Dyble, P.H. Moisander, A.D. Chapman, J. Hendrickson and H.W. Paerl. 2009. Interactions between nitrogen dynamics and the phytoplankton community in Lake George, Florida, USA. Lake Reserv. Manage. 25:1-14. Nutrient addition bioassays were conducted to examine the relationship between inorganic nutrient enrichment and phytoplankton community structure and function in Lake George in the St. Johns River System, Florida, USA. Additionally, a nitrogen budget for the lake was developed and included data from the period of this study. We identified the factors that affected cyanobacterial productivity, prevalence, and nitrogen (N2) fixation. The importance of N2 fixation to the nitrogen (N) budget of the system was also assessed. We hypothesized that N2 fixation significantly contributed to the Lake George N budget and that changing the nutrient conditions in manipulative experiments would affect rates of N2 fixation and composition of the phytoplankton, particularly the N2-fixing community. Phytoplankton primary productivity in Lake George was stimulated by the addition of both N and phosphorus (P). Phytoplankton biomass accumulation was most often enhanced by the combined addition of N and P; however, N alone was also often stimulatory. When detected, N2 fixation was always stimulated by P additions. Short-term changes in phytoplankton community composition included taxonomic shifts in response to nutrient manipulations. Fixation of N2 appeared to be a significant contributor to the N load to the lake. Human impacts that change the loading of N, P, or both N and P to Lake George may affect phytoplankton community structure (composition and biomass) and function (primary productivity and N2 fixation). These changes could have consequences for biogeochemical cycling in Lake George and potentially through the freshwater-marine continuum. Continuing nutrient management efforts in this and other similar systems must account for the activity of N2-fixing cyanobacteria, as products (carbon fixation) and drivers (sources of new nitrogen) of eutrophication. |
| Sedimentary phosphorus in a cascade of five reservoirs (Lozoya River, Central Spain) | Pilar Lopez; Rafael Marcé; Jaime Ordoñez; Iñaki Urrutia; Joan Armengol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 39 - 48 | Sedimentary phosphorus in a cascade of five reservoirs (Lozoya River, Central Spain) | Lopez, P., R. Marc, J. Ordoez, I. Irrutia and J. Armengol. 2009. Sedimentary phosphorus in a cascade of five reservoirs (Lozoya River, Central Spain). Lake Reserv. Manage. 25:39-48. The concentration of phosphorus (P), carbon (C), and nitrogen (N) in superficial sediments in a cascade of five reservoirs (Pinilla, Riosequillo, Puentes Viejas, El Villar, and El Atazar) located along the Lozoya river (Central Spain) was determined. The mean reservoir values of sedimentary phosphorus, nitrogen, and carbon increased from the first reservoir (Pinilla) to the central one (Puentes Viejas) where they reached 62 μ molP/g(dw), 5.36 mmolC/g(dw)and 0.56 mmolN/g(dw), respectively. They then followed a decreasing trend until the last reservoir (El Atazar), which presented concentrations close to those of Pinilla. Phosphorus and nitrogen usually tended to increase from the river end to the dam at each reservoir, while carbon did not show a regular trend associated to the river flow. The amount of phosphorus accumulated in sediments of the Lozoya System reservoirs was notably high (> 50 μ molP/g (dw)), especially at the three central reservoirs (Riosequillo, Puentes Viejas, and El Villar). Sedimentary phosphorus was positively related to nitrogen, small particles (∅: 2-10 μ m), and the ratio of iron to aluminium, Fe/Al, is an indicator of iron precipitation. This last variable explained more than 90% of the sedimentary phosphorus variance in four reservoirs (Pinilla, Riosequillo, El Villar, and El Atazar). In the other reservoir (Puente Viejas), sedimentary phosphorus (Psed) variance was explained by Fe/Al ratio as a main factor, but also by nitrogen as a secondary factor. Hence, association of sedimentary phosphorus to iron oxides with small size appeared as the main factor determining phosphorus accumulation in the sediments of the Lozoya reservoirs. Two main management recommendations arise from these results: (1) reduction in the flow of anoxic water from upstream reservoirs to prevent the transport of dissolved phosphate coming from internal loading, and (2) reduction in high flows that carry fine sediment particles with weakly bound P that may be released when the particle meets a new concentration of soluble reactive phosphorus in the downstream reservoirs. |
| Reconstructing the history of sediment accumulation in the Yesa reservoir: an approach for management of mountain reservoirs | Ana Navas; Blas Valero-Garcés; Leticia Gaspar; Javier MachÃn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 15 - 27 | Reconstructing the history of sediment accumulation in the Yesa reservoir: an approach for management of mountain reservoirs | Navas, A., B. Valero-Garcs, L. Gaspar and J. Machn. 2008. Reconstructing the history of sediment accumulation in the Yesa reservoir: an approach for management of mountain reservoirs. Lake Reserv. Manage. 25:15-27. The Aragn River was impounded at the foothills of the Pyrenean Internal Depression in 1959; since then sediments accumulations have decreased the reservoir storage capacity. In this work, we interpreted the history of the sediment accumulation in the Yesa reservoir based on the detailed study of two sediment cores collected at the more stable area in the reservoir. The identification of main sedimentological facies together with the analysis of the grain size distribution of the materials accumulated at the bottom of the reservoir was used for interpretations of the sedimentary dynamics. These data were compared with records of known flood events to derive a tentative chronology of the infilling process by assigning main changes observed in the facies types and sediment components to specific years. In addition to grain size data of sediments accumulated in the river channels, suspended sediments from representative sites of the Aragn Basin to the Yesa reservoir were collected during high and low waters and analysed. Grain size data and sediment composition (organic matter, carbonates) were used to assess the characteristics and the pattern of the sediment transport through the Aragn River network and the role played by lithology and land use. The results provide information on the sediment transport. This approach can be used to assess the siltation processes in Mediterranean mountain reservoirs to improve the management of water bodies by preventing their infilling. |
| Model of zebra mussel growth and water quality impacts in the Seneca River, New York | David Glaser; James R. Rhea; Daniel R. Opdyke; Kevin T. Russell; C. Kirk Ziegler; Wen Ku; Li Zheng; Joseph Mastriano | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 49 - 72 | Model of zebra mussel growth and water quality impacts in the Seneca River, New York | Glaser, D., J.R. Rhea, D.R. Opdyke, K.T. Russell, C.K. Ziegler, W. Ku, L. Zheng and J.J. Mastriano. 2009. Model of zebra mussel growth and water quality impacts in the Seneca River, New York. Lake Reserv. Manage. 25:49-72. A dynamic water quality model was developed to support management decision-making for the Seneca River, New York. The model incorporated two-dimensional hydrodynamics to simulate stratification observed within the system, a carbon-based zebra mussel growth model to account for the impact of this invasive species on water quality within the system, and a mechanistic representation of sediment diagenesis to account for zebra mussel-induced changes in carbon cycling. The Seneca River is on New York State's 303(d) list of impaired water bodies for nonattainment of dissolved oxygen criteria and is being considered as the potential receiving water for diverted effluent from an 85 million gallon per day (MGD) wastewater treatment plant (WWTP) serving the City of Syracuse, New York. The model was developed to examine the feasibility of such a diversion. The model was parameterized using site-specific field and laboratory studies and accurately simulated six years of routine, generally biweekly, river monitoring data for dissolved oxygen, chlorophyll-a, nitrogen, and phosphorus, collected over a range of flow conditions. The diagnostic application of the calibrated model provided valuable insights into the complex feedback mechanisms that exist within the system, particularly the role that zebra mussel filtration, respiration, and elimination have on phytoplankton production, sediment oxygen demand, and nutrient cycling within the system. |
| Evaluation of optimal dose and mixing regime for alum treatment of Matthiesen Creek inflow to Jameson Lake, Washington | Jillian J. Churchill; Marc W. Beutel; Peter S. Burgoon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 102 - 110 | Evaluation of optimal dose and mixing regime for alum treatment of Matthiesen Creek inflow to Jameson Lake, Washington | Churchill, J.J., M.W. Beutel and P.S. Burgoon. 2009. Evaluation of optimal dose and mixing regime for alum treatment of Matthiesen Creek inflow to Jameson Lake, Washington. Lake Reserv. Manage. 25:102-110. An innovative method of reducing external phosphorus (P) loading to lakes uses engineered systems to treat lake inflows with aluminum sulfate (alum). In this study we used a series of jar tests to examine the optimal alum dose and mixing regime to remove P from Matthiesen Creek, an important external source of P to Jameson Lake. Matthiesen Creek is a good candidate for alum treatment because the creek runs year round, and the majority of P in the spring-feed creek is in the form of bioavailable dissolved P that can be efficiently captured in alum floc. The mixing regimes in this study mimicked a range of possible treatment scenarios that relied on natural turbulence in the creek or conventional mechanical mixing, and presumed the discharge of alum floc either directly to the lake or to an on-shore settling basin. Jar tests showed that an alum dose of 5 mg-Al/L was sufficient to decrease P from around 0.13 mg-P/L to below 0.02 mg-P/L for most mixing regimes. For all mixing regimes, doses of up to 20 mg-Al/L did not depress pH below the recommended minimum pH of 6. Flash mixing prior to low-intensity mixing did not enhance P removal over low-intensity mixing alone, but flash mixing alone resulted in lower levels of P removal from creek water. Jar testing with a mixture of alum-treated creek water and lake water showed that lake waters tended to inhibit P uptake by alum floc. This, combined with the fact that high pH favors the formation of the aluminate ion which could exhibit chronic toxicity to aquatic biota, suggests that discharge of alum solids directly to the lake should be avoided. We recommend an engineered inflow treatment system on Matthiesen Creek that maintains an alum dose of 5-10 mg-Al/L under moderate mixing conditions (Gt of 1,000-3,000) with alum floc collected in an on-shore settling basin. |
| Phytoplankton dynamics in a chain of subtropical blackwater lakes: the Upper St. Johns River, Florida, USA | Millard M. Fisher; Steven J. Miller; Andrew D. Chapman; Lawrence W. Keenan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 73 - 86 | Phytoplankton dynamics in a chain of subtropical blackwater lakes: the Upper St. Johns River, Florida, USA | Fisher, M.M., S.J. Miller, A.D. Chapman and L.W. Keenan. 2009. Phytoplankton dynamics in a chain of subtropical blackwater lakes: the Upper St. Johns River, Florida, USA. Lake Reserv. Manage. 25:73-86. Spatial and seasonal patterns in phytoplankton biovolume and community composition were examined for a chain of lakes in the Upper St. Johns River (USJR), Florida, USA. There was a general downstream trend in both increasing phytoplankton biovolume, and dominance of the algal community by cyanobacteria. Total algal biovolume increased from 0.7 106μ m3/ml in the headwaters lake to 5.6 106μ m3/ml downstream in Lake Winder. Cyanobacteria dominated the downstream lakes, accounting for approximately 50% of total algal biovolume, yet constituted only 2% of total biovolume in the headwaters lake. The diatom assemblage, as well as water quality data, suggests that these blackwater lakes are mesotrophic to eutrophic and neither nitrogen nor phosphorus limited growth. Fifteen months of cyanobacterial biovolume data were compared to water quality data to determine principal regulating factors. A regression model indicates that the major factors correlated with cyanobacteria in these lakes are temperature, total Kjeldahl nitrogen, water level, and color, with temperature alone accounting for 54% of the variability in cyanobacterial biovolume. This analysis demonstrates that multiple interacting factors need to be considered when attempting to explain spatiotemporal patterns in algal dynamics. |
| The effects of residential docks on light availability and distribution of submerged aquatic vegetation in two Florida lakes | Kym Rouse Campbell; Rick Baird | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 87 - 101 | The effects of residential docks on light availability and distribution of submerged aquatic vegetation in two Florida lakes | Campbell, K.R. and R.Baird. 2009. The effects of residential docks on light availability and distribution of submerged aquatic vegetation in two Florida lakes. Lake Reserv. Manage. 25:87-101. This study was conducted to determine the effects of residential docks on the density and diversity of submerged aquatic vegetation (SAV) within two freshwater lakes in Orange County, Florida: Lake Butler and Lake Jessamine. From a lake manager's perspective, an improved understanding of the effects of docks should result in better planning and management to help ensure that additional docks do not harm the aquatic environment, while still providing reasonable access to the water. Major issues considered in this study included whether the amount of light penetrating beneath a dock affected the density and diversity of SAV growing beneath it, and whether other variables affected the density and diversity of SAV beneath docks, including lake trophic status. Ten docks and 10 reference sites were surveyed in each lake in June and July 2007. During each survey, we collected numbers and species of SAV, field water quality, surface and underwater light, dock measurements, and surrounding condition information. We documented a reduction in available light under docks with a corresponding decrease in plant density. Density of SAV was higher under docks oriented north/south compared to those oriented east/west. Overall, turbidity had the most influence on SAV diversity, while Secchi depth had the most influence on SAV diversity under docks. For this investigation overall, including beneath docks, SAV density was most affected by the percent of surface light above the SAV/bottom, while SAV diversity was most affected by the clarity of the water. |
| Spatial disconnection of plankton dynamics in an Ozark reservoir | John E. Havel; Russell G. Rhodes | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 28 - 38 | Spatial disconnection of plankton dynamics in an Ozark reservoir | Havel, J.E. and R.G. Rhodes. 2009. Spatial disconnection of plankton dynamics in an Ozark reservoir. Lake Reserv. Manage. 25:28-38. This two-year study examined spatial distribution and seasonal population dynamics of algae and zooplankton in Table Rock Lake (Missouri, USA), a large clear reservoir threatened by increased development in the watershed. Regular samples were collected from a polymictic up-lake site (10 m deep, mean Secchi transparency 1.0 m) and a monomictic down-lake site (37 m deep, 4.0 m Secchi) in the productive James River arm. Average abundance and biovolume of most algae groups showed no statistically-discernable difference between these two sites, and maximum cell densities were similar in magnitude (∼ 105 cells/mL). Exceptional were the chlorophytes, which had their highest abundance up-lake. Based on taxonomic composition, both sites appear to be dominated by pelagic algae, with little evidence of riverine immigrants. Algae and zooplankton showed rapid seasonal changes in total densities and composition, and peak abundances showed no association in time between the two sites. Although no floating or suspended colonies were ever visible in the field, cyanobacteria (particularly Oscillatoria) were common at both study sites, and we found numerous genera linked to nuisance blooms in other lakes. Zooplankton communities differed between sites, with cladocerans common in winter and spring at the down-lake site and rotifers common year round at the up-lake site. Important cladoceran grazers, such as Daphnia, were usually not abundant; however, when they were common, algae abundance was always low. |
| Role of contemporary and historic vegetation on nutrients in Missouri reservoirs: implications for developing nutrient criteria | John R. Jones; Matthew F. Knowlton; Daniel V. Obrecht; Anthony P. Thorpe; James D. Harlan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 25 | 1 | 2009 | 111 - 118 | Role of contemporary and historic vegetation on nutrients in Missouri reservoirs: implications for developing nutrient criteria | Jones, J.R., M.F. Knowlton, D.V. Obrecht, A.P. Thorpe and J.D. Harlan. 2009. Role of contemporary and historic vegetation on nutrients in Missouri reservoirs: implications for developing nutrient criteria. Lake Reserv. Manage. 25:111-118. Using vegetative survey records from the time of Euro-American settlement (circa 1815-1850) we found the proportion of historic prairie accounted for 42% of cross-system variation in total phosphorus (TP) and 48% of total nitrogen in 156 Missouri reservoirs. When combined with dam height (surrogate for lake morphometry) and hydraulic flushing rate (TP only), 56% of variation in nutrients was explained. Consistent with previous analyses, some two-thirds of variation in nutrients was accounted for by contemporary cropland, morphometry, and hydrology (TP only). Adding prairie or historic forest cover to models based on current cropland did little to increase explained variation. The relationship between reservoir nutrients and land cover is partly an artifact of past land conversion; most arable soils with inherent fertility sufficient to generate economically viable produce and suitable topography were former prairies. The cross-system analysis of Missouri reservoirs showed that nutrients in these anthropogenic ecosystems are largely determined by nonpoint input from current land use as modified by morphology and hydrology. Historic vegetation cover, however, was our best measure of baseline conditions in the reservoir catchments and contributes to the framework for developing nutrient criteria for these artificial lakes. No natural reference conditions exist for Missouri reservoirs, and we recommend setting site-specific nutrient criteria for these constructed systems. |
| Sedimentary and historical context of eutrophication and remediation in urban Lake McCarrons (Roseville, Minnesota) | Amy Myrbo | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 349 - 360 | Sedimentary and historical context of eutrophication and remediation in urban Lake McCarrons (Roseville, Minnesota) | Geochemical analysis of the varved (annually laminated) sediments of a small, deep urban lake in east-central Minnesota shows that some water-quality and watershed indicators are approaching prehistoric (pre-1850s) values after an excursion to anomalous levels during the 1920s through 1950s. This high-resolution paleolimnological information (annually resolved for most of the 20th century), including varve thickness measurements on a digital image, carbon stable isotopic composition of organic matter, and sedimentary component quantification, provides historical perspective to lake managers planning remedial measures with reference to the “natural†state of the lake, especially in regard to the perception that water quality has declined only in recent decades (i.e., in the late 20th century). The lake is at present eutrophic and oligomictic, with oxygen-depleted bottom waters enriched in dissolved solids relative to surface waters; an alum treatment has contributed to the problem of persistent stratification at the same time as it has reduced phosphorus and increased transparency in lake surface waters. The sedimentary record shows the lake's strong response to agricultural, recreational, and urban development in the watershed, gradual improvement beginning at the time of sanitary sewer installation in the 1960s, and only a minor additional response to a concerted remediation effort in the mid-1980s to 1990s. Indices of terrestrial inputs and algal productivity show evidence of a lake that was at its most heavily impacted during the mid-20th century, and which has improved in some respects since the 1960s. |
| Water quality modeling of the effects of macrophytes on dissolved oxygen in a shallow tailwater reservoir | J. Stansbury; L. Kozimor; D. Admiraal; E. Dove | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 339 - 348 | Water quality modeling of the effects of macrophytes on dissolved oxygen in a shallow tailwater reservoir | Lake Ogallala, a 260-hectare tailwater reservoir, is subject to wide fluctuations of inflow water quality and quantity. These fluctuations impact lake temperatures, water stage, dissolved oxygen (DO), and nutrients. A two-dimensional, continuous simulation hydrodynamic and water quality model, CE-QUAL-W2, was used to simulate dissolved oxygen levels and to quantify DO sources and sinks in the lake. The elements modeled include surges of low DO and temperature; high chemical oxygen demands and dissolved nutrients; response of in-lake algae, macrophytes, and epiphytes; temperature and bathymetric induced circulation patterns; and weather impacts. The model's epiphyte routine was used to simulate macrophytes. The model was able to replicate the diurnal DO fluctuations, which ranged from 2 to 12 mg/L, as well as other water quality parameters. The study found that the chemical oxygen demand depressed daily DO minima by approximately 1.5 mg/L. This study also found that macrophyte respiration was an important factor in the low daily DO minima, depressing daily DO minima approximately 2 mg/L overnight. |
| Biodiversity in southern Wisconsin storm-water retention ponds: Correlations with watershed cover and productivity | Stanley I. Dodson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 370 - 380 | Biodiversity in southern Wisconsin storm-water retention ponds: Correlations with watershed cover and productivity | This research is based on the management principle that watershed land cover is a better predictor of pond biodiversity than primary productivity. Ponds in watersheds with more than 30% lawn cover have few zooplankton species, no macrophytes, no snails, and no amphibians. A recent meta-analysis generated the hypothesis that watershed (catchment basin) land cover is a better predictor of lake biodiversity than traditional predictors (such as in-lake primary productivity) if the watershed includes human development (agriculture, residential, or urban). This hypothesis was tested via a field survey of 23 similar-sized artificial ponds in southern Wisconsin. The ponds had similar climate and geology, but differed in the relative proportions of land cover in the watershed. Twelve environmental variables (including pond area, depth, and primary productivity surrogates) and seven watershed land cover variables were correlated with biodiversity measures of seven major aquatic communities. Percent lawn cover was negatively correlated with zooplankton richness (r2 = 0.41), macrophyte abundance (r2 = 61), molluscan presence (r2 = 0.48), and amphibian presence (r2 = 0.55 for spring species and r2 = 0.78 for summer species). Fish presence was negatively correlated with percent watershed covered by meadow (r2 = 0.16). Chlorophyll a (a primary productivity surrogate) was negatively correlated with three groups: zooplankton richness (r2 = 0.18), macrophyte abundance (r2 = 0.23), and molluscan presence/absence (r2 = 0.31). Total phosphorus and nitrogen (surrogates of in-lake primary productivity) were weakly correlated with biodiversity. |
| Predicting Eurasian watermilfoil invasions in Minnesota | Sarah S. Roley; Raymond M. Newman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 361 - 369 | Predicting Eurasian watermilfoil invasions in Minnesota | Eurasian watermilfoil is an invasive aquatic macrophyte that can be difficult to control once established in a lake. Identifying characteristics of lakes susceptible to Eurasian watermilfoil establishment can aid management by allowing managers to focus their education and monitoring efforts on susceptible lakes. Using linear discriminant function analysis and logistic regression to analyze known occurrences of Eurasian watermilfoil, we developed models to predict susceptible lakes in Minnesota. The most reliable predictors of Eurasian watermilfoil invasion were distance to the nearest invaded lake and duration of that invasion, indicating that transport (exposure) is an important variable. However, exposure is not a guarantee of establishment: lake size, alkalinity, Secchi depth, and lake depth were also significant predictors of invasion. Specifically, large deep lakes with moderate to high alkalinity and moderate Secchi depth were more likely to be invaded. Models predicted an additional 2,100 to more than 4,700 of Minnesota's more than 12,000 lakes could be invaded by Eurasian watermilfoil. |
| Effects of sediment resuspension on nutrient concentrations and algal biomass in reservoirs of the Central Plains | Andrew R. Dzialowski; Shih-Hsien Wang; Niang-Choo Lim; Jason H. Beury; Donald G. Huggins | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 313 - 320 | Effects of sediment resuspension on nutrient concentrations and algal biomass in reservoirs of the Central Plains | Historically, lake and reservoir management has focused on controlling external nutrient loading. However, it is becoming increasingly clear that internal mechanisms, such as the episodic resuspension of benthic sediments, can also contribute to the processes of eutrophication. We conducted laboratory bioassay experiments to determine how resuspended sediments affected nutrient concentrations and algal biomass in four eutrophic reservoirs of the Central Plains. Surficial sediments and surface water were collected from each reservoir and returned to the laboratory where they were added to 1-L bioassay bottles at five turbidity concentrations (0, 50, 150, 250, and 500 NTUs). Sediments in the bioassay bottles were resuspended daily, and algal biomass (measured as relative fluorescence) was measured for 11-14 days. Resuspended sediments at the lowest experimental turbidity concentration, 50 NTUs, had highly significant effects on algal biomass in each of the sediment resuspension bioassays. Algal biomass appeared to increase following experimental sediment resuspension due to an increase in available nutrients and/or the establishment of algae (meroplankton) from the sediment. Overall, our results highlight the importance of considering internal mechanisms when developing reservoir management and restoration plans for these important ecosystems. |
| Evaluation of the impact of water dilution within the hypereutrophic Lake Barato, Japan | Ryuichiro Shinohara; Takeshi Okunishi; Kumiko Adachi; Le Son Viet; Hiroaki Mine; Toshihiko Yamashita; Masahiko Isobe | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 301 - 312 | Evaluation of the impact of water dilution within the hypereutrophic Lake Barato, Japan | Field data and three-dimensional numerical simulations were used to evaluate the impact of water dilution on eutrophication. To dilute eutrophic water in Lake Barato, Japan, an Inlet Project was carried out during the summer of 2005 via a 1 m3/sec inlet. River water was discharged from the margin of the upper basin of the lake to dilute the water. We undertook a numerical simulation of total nitrogen (TN) and total phosphorus (TP) distribution considering five inlet cases by using Princeton Ocean Model (POM). Total N and TP concentrations of inlet water were TN: 1.3 mg/l and TP: 0.08 mg/l. Model results suggest the most effective and feasible way to achieve dilution is via a 5 m3/sec inlet (78% related to the total volume in the lake) and opening the Shinko Gate, connecting the lake with Ishikari Bay. Following this scheme, TN and TP concentrations would be reduced by 28% following 30 days of discharge according to the simulation results. |
| Lack of exotic hydrilla infestation effects on plant, fish and aquatic bird community measures | Mark V. Hoyer; Melissa Woods Jackson; Micheal S. Allen; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 331 - 338 | Lack of exotic hydrilla infestation effects on plant, fish and aquatic bird community measures | The invasion of hydrilla into North American lakes has provoked concern over loss of native flora and fauna and resulted in costly suppression efforts. We used two data sets to determine if common measures of ecosystem health; abundance, species richness, diversity and evenness, were affected by the presence of hydrilla. Data Set 1 consisted of 27 Florida lakes, 11 of which had hydrilla present for approximately 4-8 years in varying abundances, and 16 did not have hydrilla. Given the number of lakes, each was sampled only once in the summers of 1986-1990 for community measures of aquatic plants, birds, and fish. Data Set 2 consisted of 12 lakes, six with abundant hydrilla for over 23 years and six without hydrilla. These lakes were sampled every year in the summer (with a few exceptions due to weather conditions) between 1999 and 2006 for community measures of aquatic plants and fish. The results for both data sets show that presence of hydrilla had no statistically significant effect (P > 0.05) on all community measures tested (i.e., richness, diversity, abundance). Our conclusions support the hypothesis that hydrilla in these Florida lakes has occupied a mostly vacant ecological niche and has not affected the occurrence or relative composition of native species of aquatic plants, birds, and fish. Because pond experiments have found negative effects of hydrilla, further focused research is needed to assist management decisions when considerable resources are to be spent each year on hydrilla suppression. |
| Seasonal changes in the zooplankton abundances of the reservoir Valle de Bravo (State of Mexico, Mexico) | S. Nandini; MartÃn Merino-Ibarra; S. S. S. Sarma | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 321 - 330 | Seasonal changes in the zooplankton abundances of the reservoir Valle de Bravo (State of Mexico, Mexico) | Valle de Bravo is one of largest drinking water reservoirs in Mexico, serving nearly 12% of Mexico City's population of 26 million. We studied the monthly variations in the zooplankton density and diversity for one year (November 2004 to October 2005) at five different depths (2, 4, 8, 12, and 20 m) at each of the five sites of the reservoir. The water body was generally alkaline; pH decreased with increasing depth. Dissolved oxygen also decreased drastically with depth, from an average of 8 mg/L to less than 1 mg/L. Chlorophyll a concentration varied considerably (2.6 ± 0.06 to 12.5 ± 2.8 μg/L) both seasonally and with depth. Secchi depth averaged 1.65 m and varied between 0.63 and 3.21 m along the seasons but exhibited minimal differences among sites. Differences in zooplankton abundance and composition were small among sites, supporting the theory that anthropogenic disturbances affect the reservoir as a whole. The mean total zooplankton density was about 400 ± 293 ind./L, mostly composed of rotifer species, particularly Keratella cochlearis, Polyarthra vulgaris, and Trichocerca similis. Densities of K. cochlearis at 2-m depth exceeded 1800 ind./L during the rainy season (May-July). Average density of P. vulgaris was 200 ± 133 ind./L, while that of T. similis was half that amount. The dominant cladoceran taxa were Bosmina longirostris, Chydorus sphaericus, and Daphnia laevis. An inverse relationship between depth and zooplankton abundance and depth and diversity was observed. In contrast, we observed a direct relation between the mean rotifer and cladoceran density. Shannon-Wiener's species diversity index ranged between 1.00 and 4.09. Fourteen of the rotifer species found are new records for Valle de Bravo and another 13 species observed earlier were not encountered in the present study. The overall trends in both the densities and dominance of rotifer species of the reservoir did not essentially change during the last five years. Our data point toward the need for an integrated management of Valle de Bravo. |
| Assessing contribution of DOC from sediments to a drinking-water reservoir using optical profiling | Bryan D. Downing; Brian A. Bergamaschi; David G. Evans; Emmanuel Boss | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 4 | 2008 | 381 - 391 | Assessing contribution of DOC from sediments to a drinking-water reservoir using optical profiling | Understanding the sources of dissolved organic carbon (DOC) in drinking-water reservoirs is an important management issue because DOC may form disinfection by-products, interfere with disinfection, or increase treatment costs. DOC may be derived from a host of sources—algal production of DOC in the reservoir, marginal production of DOC from mucks and vascular plants at the margins, and sediments in the reservoir. The purpose of this study was to assess if release of DOC from reservoir sediments containing ferric chloride coagulant was a significant source of DOC to the reservoir. We examined the source-specific contributions of DOC using a profiling system to measure the in situ distribution of optical properties of absorption and fluorescence at various locations in the reservoir. Vertical optical profiles were coupled with discrete water samples measured in the laboratory for DOC concentration and optical properties: absorption spectra and excitation emission matrix spectra (EEMs). Modeling the in situ optical data permitted estimation of the bulk DOC profile in the reservoir as well as separation into source-specific contributions. Analysis of the source-specific profiles and their associated optical characteristics indicated that the sedimentary source of DOC to the reservoir is significant and that this DOC is labile in the reservoir. We conclude that optical profiling is a useful technique for understanding complex biogeochemical processes in a reservoir. |
| Landscape structure and habitat composition in reservoirs, lakes, and rivers | E. G. Drakou; A. S. Kallimanis; S. P. Sgardelis; J. D. Pantis | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 3 | 2008 | 244 - 260 | Landscape structure and habitat composition in reservoirs, lakes, and rivers | We compared reservoirs that were proposed to be included in the Greek Natura 2000 network of protected sites, with natural lakes and rivers from the same network. We analyzed landscape spatial pattern, habitat type composition, and spatial pattern of human activities. We found that the landscapes of reservoirs are distinct from those of rivers and natural lakes. More specifically, the reservoir water bodies were characterized by a more complex shape than the water bodies of rivers and lakes. Furthermore, based upon the landscape spatial pattern of the entire protected area, we could clearly discriminate among the three aquatic ecosystem types. It was also possible to discriminate these ecosystem types based upon the habitat composition of the surrounding landscape. The habitat composition among the different sites showed low similarity. Human presence in all sites was documented, but its spatial pattern was not differentiated among the three aquatic ecosystem types. The results highlight the ambiguous nature of reservoirs; thus, we advocate the need for specific management measures for reservoirs that will accomplish both their intended purpose and the conservation of habitat composition and landscape structure. |
| Predicting the spatial mud energy and mud deposition boundary depth in a small boreal reservoir before and after draw down | P. M. Cooley; W. G. Franzin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 3 | 2008 | 261 - 272 | Predicting the spatial mud energy and mud deposition boundary depth in a small boreal reservoir before and after draw down | We predicted the distribution of coarse- and fine-grained substrata in a small boreal lake at natural lake level and then assessed if the extents of sediment focusing due to water level manipulation could be predicted. The littoral substratum and upper limit to the distribution of mud was mapped completely prior to experimental draw down and the upper depth limit of mud was mapped in each of the first 2 years of a new water level regime. Six published equations for estimating the position of the mud boundary and the lower limit of surface wave energy were applied using maps of fetch, slope, and depth. At natural lake level, the agreement between observed and estimated mud boundaries in deep water was remarkable (<5 m horizontal). Agreement between the depth of mixing by surface waves and mud boundaries in shallow water was closest, at times exact, for equations with estimates similar to maximum wave height. However, the size of waves responsible for the shallow sediment boundaries remains unclear due to natural variation of lake level. All models overestimated energy in shallow depositional settings where exposure and slope was low. Refocusing of sediment due to maximum winter draw down of 3 m resulted in contraction and expansion of the profundal zone; a net decrease in area of 3% was evident after 2 years. Our results demonstrate that mud deposition models can be used in deep lake basins to map the littoral and profundal zones. Sediment refocusing in the first few years of winter draw down is forced mainly by falling lake levels. The interpretation of littoral habitat complexity can be simplified by understanding the lake-wide spatial pattern of erosion, transport, and deposition of sediments. |
| Probabilistic model for temperature and turbidity in a reservoir withdrawal | Rakesh K. Gelda; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 3 | 2008 | 219 - 230 | Probabilistic model for temperature and turbidity in a reservoir withdrawal | The development and application of a probabilistic modeling framework to conduct a priori simulations (forecasts) of temperature (Tw) and turbidity (Tn,w) in the withdrawal of a water supply impoundment, Schoharie Reservoir, N.Y., is documented. The model framework incorporates previously tested transport/hydrothermal and turbidity submodels, long-term (57 years) records of meteorology, hydrology, and operations, and empirical models to specify other drivers, including tributary temperature and turbidity inputs, over the same period. The probabilistic framework closely simulates the observed wide variations in Tw and Tn,w for an 18-year period. The major sources of variability for both Tw and Tn,w were demonstrated to be variations in hydrologic and linked operating conditions. Application of the probabilistic framework indicates the goal for Tw could be met continuously with a multi-level intake (MLI) facility instead of the existing single, fixed-depth intake. However, this management alternative would provide only modest benefits for Tn,w levels. The model predicts that moving the MLI facility to a deeper portion of the reservoir will not improve the water quality of the withdrawal within the context of management goals. |
| Minnesota's approach to lake nutrient criteria development | Steven Heiskary; Bruce Wilson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 3 | 2008 | 282 - 297 | Minnesota's approach to lake nutrient criteria development | Ecoregion-based phosphorus “criteria†that reflect the diversity of lake condition, varying from deep pristine lakes in the north to shallow hypereutrophic lakes in the south, were developed by the Minnesota Pollution Control Agency (MPCA) in the late 1980s. Since then the criteria, including several refinements, have been widely used for local, state, and federal lake watershed management efforts in Minnesota. More recently, the criteria have been used to define thresholds for Clean Water Act Section 303(d) listing of nutrient-impaired lakes and are being advanced as lake standards to protect a wide diversity of beneficial uses. This paper summarizes the evolution of these criteria and describes data and research used in their development. A weight-of-evidence approach describes how this information was used to refine the criteria values. |
| Secchi transparency of Boulder Basin, Lake Mead, Arizona-Nevada: 1990-2007 | James F. LaBounty | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 3 | 2008 | 207 - 218 | Secchi transparency of Boulder Basin, Lake Mead, Arizona-Nevada: 1990-2007 | Over 5,500 individual Secchi readings were taken from Boulder Basin of Lake Mead, Nevada-Arizona, between July 1990 and December 2007. Annual and seasonal patterns are plainly displayed by these data. Variations in Secchi depth measurements are both spatial and temporal. Peak water transparency >15 m generally occurs in April and March and at sampling locations along the thalweg of the Colorado River channel in the Outer portion of Boulder Basin. Transparency steadily decreases toward the tributary inflow into Las Vegas Bay. Transparency in open water of Las Vegas Bay ranges from <1 m during the growing season to 5-7 m in winter. These differences are generally driven by varying algal production which decreases in a cline from Las Vegas Bay to the Outer Basin. Entrainment of small sediment particles from the urban inflow also influences water transparency. Steady lowering of the reservoir during the 2000 to 2007 drought exacerbated the influence of turbidity due to entrainment of former lake bottom sediments into the epilimnion. However, the strongest statistical relationships with decreasing Secchi transparency are with chlorophyll a (chl-a) and total phosphorus (TP). The patterns and relationships presented establish the nature of Boulder Basin's water clarity to 2008 that will be useful in light of imminent and future alterations of the aquatic ecosystem by both anthropogenic and nonanthropogenic factors. Perhaps the largest change will occur due to the recent introduction of the quagga mussel (Dresseina rostriformis bugensis). After discovery in January 2007, the mussel population has been increasing rapidly. The data sets in this presentation form the basis of conditions in Boulder Basin prior to the introduction of quagga mussels. |
| Turbidity and temperature patterns in a reservoir and its primary tributary from robotic monitoring: Implications for managing the quality of withdrawals | Anthony R. Prestigiacomo; Steven W. Effler; David M. O'Donnell; David G. Smith; Donald Pierson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 3 | 2008 | 231 - 243 | Turbidity and temperature patterns in a reservoir and its primary tributary from robotic monitoring: Implications for managing the quality of withdrawals | A robotic water quality monitoring network, consisting of 2 in-reservoir profiling platforms and a unit positioned in the primary tributary, was used to document patterns of temperature (T) and turbidity (Tn) and the impact of runoff events on Tn levels over the spring to fall interval of 3 years. The patterns were evaluated in the context of water quality goals for T and Tn for reservoir withdrawal and potential benefits of specified management alternatives. Exceedences of a proposed withdrawal T goal of 21.1 °C (70 °F) and a conservative representation of the Tn goal of 15 NTU were demonstrated. The exceedences occurred in late summer during intervals of extensive drawdown for T and irregularly following runoff events for Tn. Conspicuous increases in Tn in the tributary and lacustrine portions of the reservoir were demonstrated in response to all monitored runoff events (n = 34). Lacustrine levels exceeded 75 NTU following several major events. The turbidity load from the tributary usually enters the reservoir as a turbid density current during runoff events, at a depth predicted well by stream temperature. The high frequency and vertical resolution attributes of the robotic monitoring (2 profiles per day for reservoir deployments) were invaluable in resolving impacts because these were usually attenuated within a week following events. The diminishment of reservoir Tn levels following events was demonstrated to be well represented by a first-order loss rate. The loss rate for the largest runoff event of the study (return interval ~25 y) was more than an order of magnitude lower than any other, indicating a difference in settling attributes of turbidity-causing particles for this extreme case. Benefits from a shift to delayed withdrawals for the existing intake, or installation of a multi-level intake facility, for improving status with respect to the water quality goals are suggested from the monitoring data. However, continuously meeting the Tn goals for particularly severe events may not be feasible through these approaches. |
| Nutrient budgets and river impoundments: Interannual variation and implications for detecting future changes | J. A. Ferris; J. T. Lehman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 3 | 2008 | 273 - 281 | Nutrient budgets and river impoundments: Interannual variation and implications for detecting future changes | Temporal variability at monthly and annual scales was quantified at the inlets and outlets of 3 sequential impoundments for total phosphorus, dissolved phosphorus (TP), total nitrogen (TN), dissolved nitrogen, particulate nitrogen, colored dissolved organic matter, specific conductance, and pH over three years. Chlorophyll a (Chl-a) was measured within the largest of the 3 impoundments; Secchi disk transparency depth was measured over 9 years. The data were analyzed to characterize “ordinary†temporal variability, and statistical models were constructed to evaluate the sampling effort that would be required to detect predicted changes in response to a municipal ordinance banning phosphorus in lawn fertilizers, as well as to possible removal of the dam forming the middle impoundment. Changes of 25% in monthly mean value would require weekly samples during the summer for only 1 or 2 years for TN and TP, but about 8 years for Chl-a to achieve statistical confidence that conditions had changed. Bioassay experiments in the most upstream and largest of the 3 impoundments indicated that water residence times are in general too short to permit phytoplankton the opportunity to develop populations large enough to alter biogeochemistry substantially in any of the impoundments. Mass balance calculations tended to confirm this conclusion; the reservoirs acted neither as nutrient sources nor sinks over the period of study. |
| Short-term effects of a buffered alum treatment on Green Lake sediment phosphorus speciation | Rebecca A. Dugopolski; Emil Rydin; Michael T. Brett | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 2 | 2008 | 181 - 189 | Short-term effects of a buffered alum treatment on Green Lake sediment phosphorus speciation | Green Lake, Washington, was treated with a dose of 24 mg Al/L aluminum sulfate (alum) and sodium aluminate during March-April 2004 to reduce dissolved phosphorus concentrations to ameliorate a variety of eutrophication-related problems. Four sediment cores collected six months after the alum treatment in Green Lake were used to examine the short-term effects of alum on sediment phosphorus speciation. Peaks in aluminum bound phosphorus (Al-P) and total aluminum (Tot-Al) were observed in three of the four cores analyzed, resulting in an average ratio of added Al to Al-P formed (Al:Al-P) of 112:1. By comparing this ratio to the average ratio of ~11:1 found in other alum-treated Washington lakes, it can be inferred that approximately 10% of the binding capacity of the added Al had been utilized. Assuming a final ratio of Al:Al-P of 11:1, the added Al has the potential capacity to bind a total of 21.6 g/m2 of P. The amount of sediment inorganic P that supports internal loading (Fe-P and labile-P) in the fall of 2004 was determined to be 2.8 g/m2. Thus the quantity of alum added to Green Lake should be sufficient to inactivate the remaining inorganic mobile-P and to control future P mobilization from the pool of organic sediment P. |
| Nutrients, seston, and transparency of Missouri reservoirs and oxbow lakes: An analysis of regional limnology | John R. Jones; Daniel V. Obrecht; Bruce D. Perkins; Matthew F. Knowlton; Anthony P. Thorpe; Shohei Watanabe; Robert R. Bacon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 2 | 2008 | 155 - 180 | Nutrients, seston, and transparency of Missouri reservoirs and oxbow lakes: An analysis of regional limnology | A long-term (1978-2007) summer monitoring study of 167 Missouri reservoirs and floodplain lakes shows wide ranges in the trophic state variables total phosphorus (TP; 6-395 μg/L for reservoir means), total nitrogen (TN; 200-3290 μg/L), chlorophyll (Chl; 1-223 μg/L) and Secchi depth (0.15-4.3 m). There are strong regional contrasts between eutrophic-hypereutrophic water bodies in the predominantly agricultural Osage Plains, Glaciated Plains and Big Rivers sections and the mostly oligotrophic-mesotrophic reservoirs in the largely forested Ozark Highlands. The ecotonal Ozark Border was intermediate. Missouri reservoirs had slightly less TN relative to TP than predicted by global models, but TN:TP (median = 18.4) is typical of North American lakes and was about five- fold lower in the most enriched reservoirs compared to the least enriched ones. Concentrations of seston, measured as total suspended solids (TSS), volatile suspended solids (VSS), nonvolatile suspended solids (NVSS), filterable (small) suspended solids (fTSS) and the sum of all fractions (ΣTSS), were strongly correlated with TP, TN, and Secchi depth. The proportion of mineral seston (NVSS, fTSS) increased with TSS and was the dominant fraction in most reservoirs, especially in the agricultural regions. Phytoplankton was dominated by small forms (<11 μm), and Cyanophyta were the most common algae comprising a median 46% of phytoplankton biovolume. Chlorophyll-nutrient regressions showed a dominant effect of TP (r2 = 0.83 for reservoir means) with a lesser, negative effect of mineral seston (NAS or fTSS, partial r2 ~ 0.05). Secchi depth was more strongly controlled by mineral seston than by phytoplankton such that Secchi was a better predictor of nutrients (especially TP) than algal biomass. Frequency of algal blooms (Chl >10 μg/L) and Secchi <1 m increased sigmoidally with TP and TN with midrange nutrient concentrations (TP 20-50 μg/L, TN 400-700 μg/L) showing the greatest response to change. Trophic state criteria appropriate for Missouri reservoirs are similar to other north temperate lakes except for Secchi depth for which cutpoints are much lower because of nonalgal turbidity. |
| The effects of water level fluctuations and some physical and chemical variables on the macrophyte density in Lake Işıklı, Turkey | Cengiz Koç | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 2 | 2008 | 196 - 206 | The effects of water level fluctuations and some physical and chemical variables on the macrophyte density in Lake Iıklı, Turkey | The effects of water level fluctuations and some water quality variables of Lake Iıklı (western Turkey) on the density of water macrophytes were investigated between 1987 and 2005. Water depth, light transmission, suspended solids, and macronutrients were analyzed to determine the water quality of the lake and compared to dry and wet biomass of macrophytes. Light transmission and water level were identified as the main factors for the increase of macrophyte density in the lake. At minimum surface elevations, the decline in lake surface area accompanied the density-dependent decline of macrophytes during the September-November period. Subsequent increased surface elevation (in March-May) also restricted the plant growth through decreased light availability. |
| Monitoring periphyton in lakes experiencing shoreline development | Daniel Lambert; Antonella Cattaneo | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 2 | 2008 | 190 - 195 | Monitoring periphyton in lakes experiencing shoreline development | Early detection of degradation is crucial in previously pristine lakes experiencing residential development along their shores. Despite suggestions that the littoral zone responds to anthropogenic disturbance before open water, the use of periphyton for monitoring lake trophic status has been hindered by the heterogeneous distribution of this community. We examined the response of periphyton growing on different natural substrata — rocks, wood, sediments, and macrophytes — as well as on introduced plastic strips along a gradient of residential development in the Laurentian lakes (Quebec). We measured periphyton biomass as chlorophyll a and as thickness estimated with a ruler with the goal to evaluate the best method to monitor the incipient degradation of these lakes. Our findings suggest that rocks are the best substratum to sample because they are ubiquitous, and epilithic algae show a stronger response to shoreline residential development than algae on other substrata. Measurement of epilithon thickness appears a fast and reliable tool for estimating epilithon biomass. If measurements of chlorophyll a require several field and laboratory manipulations that are not readily available for voluntary lake monitoring by residents, measurement of periphyton thickness on rocks may allow examining spatial and temporal changes in a large number of lakes. |
| Modeling the influence of land use on groundwater chloride loading to lakes | Paul M. McGinley | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 2 | 2008 | 112 - 121 | Modeling the influence of land use on groundwater chloride loading to lakes | Concern over potential ecological impacts of rising chloride concentrations in lakes has intensified interest in predicting how chloride concentrations in lakes will change over time. Since the 1970s, chloride concentrations have risen in a group of central Wisconsin lakes. The principal source of water to these lakes is groundwater, and rising chloride concentrations have coincided with increased chloride use within the groundwater contributing areas. A groundwater lake loading model was developed to show how chloride sources in groundwater-contributing areas change chloride concentrations in lakes. By using this model with measured chloride concentrations from the lakes, the chloride exported from different land uses was estimated. Chloride export from agricultural and residential land uses was estimated to be 41 kg/ha·yr and 51 kg/home·yr, respectively. Highway deicing was determined to be a minor source of chloride to these lakes due to the low density of primary roads. Chloride concentrations will increase in these lakes until they are at steady-state with respect to chloride loading. The groundwater lake loading model showed that concentrations in these lakes average 50% of their predicted steady-state concentrations, but individually they range from <10% to >90% of their ultimate concentrations. |
| Growth, condition, diet, and consumption rates of northern pike in three Arizona reservoirs | Jon M. Flinders; Scott A. Bonar | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 2 | 2008 | 99 - 111 | Growth, condition, diet, and consumption rates of northern pike in three Arizona reservoirs | Northern pike (Esox lucius L.) introductions are controversial in the western United States due to suspected impacts they might have on established sport fisheries and potential illegal introductions. Three Arizona reservoirs, Parker Canyon Lake, Upper Lake Mary and Long Lake were sampled to examine the diet, consumption dynamics, and growth of northern pike. Northern pike diets varied by season and reservoir. In Parker Canyon Lake, diets were dominated by rainbow trout in winter and spring and bluegill and green sunfish in the fall. In Long Lake the northern pike ate crayfish in spring and early summer and switched to young of the year common carp in summer and fall. Black crappie, golden shiners, and crayfish were the major prey in Upper Lake Mary during spring, but they switched to stocked rainbow trout in the fall. Northern pike growth was in the high range of growth reported throughout the United States. Estimated northern pike specific consumption rate (scr) of rainbow trout (g/g/d 10-6) was greatest in Upper Lake Mary (scr = 329.1 ± 23.7 g/g/d 10-6) where stocked fingerling (<120 mm total length [TL]) rainbow trout were most vulnerable to these predators, compared to larger (>280 mm TL) rainbow trout stocked in Long Lake (scr = 1.4 ± 0.1 g/g/d 10-6) and Parker Canyon Lake (scr = 287.2 ± 15.1 g/g/d 10-6) where catchable-sized rainbow trout were stocked. Managers should consider the cost-benefits of stocking fish >200 mm TL in lakes containing northern pike. |
| Development of phosphorus load reduction goals for seven lakes in the Upper Ocklawaha River Basin, Florida | Rolland S. Fulton III; Dale Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 2 | 2008 | 139 - 154 | Development of phosphorus load reduction goals for seven lakes in the Upper Ocklawaha River Basin, Florida | External phosphorus loading targets have been developed for seven lakes in the Upper Ocklawaha River basin (UORB), and for six of these lakes the loading targets have been used as a basis for total maximum daily loads (TMDLs). External phosphorus loads for the seven lakes were estimated from 1986-2005. Three of the lakes that have received partial reductions in external loads have shown proportional reductions in phosphorus concentrations. Natural background phosphorus concentrations for the lakes were determined through a weight-of-evidence approach combining existing concentrations in reference lakes and modeling of natural background conditions in the basin. Target phosphorus concentrations were established by allowing a 10% degradation from natural background water transparency, as specified in Florida water quality standards. Data collected from the UORB lakes were analyzed to determine the relationship between phosphorus concentrations and water transparency. Target phosphorus concentrations ranged from 14-32 μg/L, which range from 15-100% of existing concentrations in the lakes. Recommended external phosphorus load reductions for the lakes range from 0 to 85%. We estimated that meeting the target phosphorus concentrations in the lakes with poorest water quality would reduce mean chlorophyll a concentrations up to 80%, substantially reduce algal bloom frequencies, and more than double mean Secchi transparency. |
| Implications of redox processes for the rehabilitation of an urban lake, Onondaga Lake, New York | Steven W. Effler; David A. Matthews | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 2 | 2008 | 122 - 138 | Implications of redox processes for the rehabilitation of an urban lake, Onondaga Lake, New York | A synthesis of the impacts of domestic and industrial wastes on oxygen resources and redox conditions of polluted Onondaga Lake, Syracuse, N.Y., is presented based on a long-term (1978-2005) monitoring program. Insights from this retrospective analysis are used to evaluate management alternatives for the remediation of oxygen resources and redox conditions. Reduced byproducts of anaerobic metabolism accumulated annually in the hypolimnion, causing low dissolved oxygen (DO) concentrations in the upper waters during fall turnover. The high natural sulfate (SO42-) concentration of the lake promoted DO depletion and the production of methylmercury (CH3Hg+). Severe depletions of DO occurred annually in the upper waters during fall mixing, representing violations of water quality standards for extended intervals from 1978 to 1996. Depletions of DO during fall were less severe from 1997 to 2004. The improvement is reported to be in response to: (1) more routine occurrence of spring turnover following closure of an industry; (2) reduction in primary productivity; (3) return of large bodied Daphnia from closure of the industry; (4) satisfaction of historic debt from earlier higher primary production levels; and (5) year-round nitrification at a contributing domestic wastewater facility. Additional improvements in oxygen resources and decreases in SO42- reduction are anticipated based on mandated future upgrades of phosphorus and ammonia treatment at the wastewater facility. Prevailing DO conditions during fall turnover, particularly within the context of anticipated improvements from the mandated upgrades, indicate hypolimnetic aeration or oxygenation is not required to meet water quality goals. Amendments to the hypolimnetic pool of NO3- are recommended instead of aeration or oxygenation to inhibit production of CH3Hg+ by SO42- reducing bacteria. |
| Seasonal increases in polycyclic aromatic hydrocarbons related to two-stroke engine use in a small Alaskan lake | Stanley D. Rice; Larry Holland; Adam Moles | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 10 - 17 | Seasonal increases in polycyclic aromatic hydrocarbons related to two-stroke engine use in a small Alaskan lake | To determine if hydrocarbon levels in salmon-rearing lakes are affected by seasonal increases in the number of two-stroke powered watercraft, passive hydrocarbon sampling devices were deployed in Auke Lake in southeast Alaska for five successive summers (1999-2003). Estimates of the number of two-stroke powered water craft were made by daily census in 2003. Passive samplers mimic the bioconcentration of trace waterborne lipophilic contaminants by living organisms and are used worldwide for in situ monitoring of organic contaminants such as polycyclic aromatic hydrocarbons (PAHs). Monthly increases in PAHs coincided with monthly increases in the number of two-stroke powered watercraft (jet skis and powerboats) on the lake during the summer. This increase in PAHs varied in magnitude from year to year. PAHs were detected in the surface waters (1 m), particularly in high use areas, and were not detected at 9 m depth. These localized seasonal inputs appeared to come primarily from recreational watercraft rather than from runoff. Alaska's recreational boating season is very compressed and coincides with migrations of anadromous fish. Increased use of two-stroke engines may transfer enough hydrocarbons to the lake to affect fish populations. |
| Effects of oxygen and nitrate on nutrient release from profundal sediments of a large, oligo-mesotrophic reservoir, Lake Mathews, California | Marc W. Beutel; Alex J. Horne; William D. Taylor; Richard F. Losee; Randy D. Whitney | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 18 - 29 | Effects of oxygen and nitrate on nutrient release from profundal sediments of a large, oligo-mesotrophic reservoir, Lake Mathews, California | Lake Mathews is a large, oligo-mesotrophic reservoir located in Southern California. The reservoir has elevated levels of nitrate and periodically experiences hypolimnetic anoxia. Experimental sediment-water chamber incubations and reservoir water quality monitoring were conducted to evaluate how oxygen and nitrate in overlaying water affect nutrient release from profundal sediments and internal nutrient loading. In experimental incubations, under nitrate-free anoxic conditions, sediment nutrient release rates were 3.4 ± 0.8 mg-P/m2 ·d for phosphate and 2.8 ± 1.2 mg-N/m2 ·d for ammonia (average ± standard deviation; n = 6). Oxygen repressed phosphate release and greatly diminished ammonia release from sediments in experimental incubations while nitrate only repressed phosphate release. Similar nutrient release dynamics were observed in the reservoir. Nutrient release rates estimated from seasonal nutrient profiles collected from the reservoir were 3.4 mg-P/m2 ·d for phosphate and 2.5 mg-N/m2 ·d for ammonia. Ammonia accumulation in the hypolimnion commenced with the onset of anoxic conditions, but phosphate accumulation did not start until nitrate disappeared from bottom waters approximately 6 weeks later. The time lag decreased total internal phosphorus loading by approximately 25% relative to hypothetical nitrate-free conditions. Laboratory and field data show that both oxygen and nitrate repress sediment phosphate release, likely via the maintenance of an oxidized surficial sediment layer that retains phosphate in iron-oxide complexes. However, only oxygen and not nitrate was effective in decreasing sediment ammonia release, likely by enhancing biological nitrification and assimilation in surficial sediments under oxic conditions. A number of in-lake management strategies have been developed to inhibit internal nutrient loading including calcium nitrate addition, aluminum sulfate addition, and oxygenation. In our view, the deliberate addition of nitrate to lakes and reservoirs poses several risks that must be carefully considered when evaluating strategies to control sediment phosphorus release. |
| The role of river inputs on the hypolimnetic chemistry of a productive reservoir: implications for management of anoxia and total phosphorus internal loading | Rafael Marcé; Enrique Moreno-Ostos; Joan Armengol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 87 - 98 | The role of river inputs on the hypolimnetic chemistry of a productive reservoir: implications for management of anoxia and total phosphorus internal loading | The effect of DOC and nitrate river inputs on summer hypolimnetic oxygen and nutrient dynamics in the advective-dominated, canyon-shaped Sau Reservoir (Spain) was investigated using 11 years of monitoring data. River water entering the reservoir during summer was the main driver defining hypolimnetic oxygen and nutrient concentration. Thus, volume-normalized hypolimnetic oxygen concentration was highly correlated with the river DOC, but not significantly correlated with surrogates of the epilimnetic primary production or with in-lake features. Also, the areal extent of anoxia and nitrate concentration controlled total phosphorus content in the hypolimnion, suggesting that the river DOC and nitrate inputs control internal load of phosphorus. Because improvement of the river water quality was the consequence of implementation of advanced wastewater treatment plants in the reservoir watershed, we advocate these solutions to manage reservoir eutrophication problems. Our results should prompt reservoir limnologists to always take into account the probable, direct effect of allochthonous sources in the hypolimnetic oxygen content and nutrient dynamics, especially in human-impacted systems. |
| Role of land cover and hydrology in determining nutrients in mid-continent reservoirs: implications for nutrient criteria and management | John R. Jones; Matthew F. knowlton; Daniel V. Obrecht | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 1 - 9 | Role of land cover and hydrology in determining nutrients in mid-continent reservoirs: implications for nutrient criteria and management | Effects of nutrient input, hydraulic flushing rate and depth on reservoir nutrients were examined in the mid-continent landscape of the Ozark Highlands and Plains in Missouri and Plains of southern Iowa. Regionally the clear south-to-north increase in reservoir nutrients, amounting to a 4-fold increase in median total phosphorus (TP) and 3-fold increase in median total nitrogen (TN), showed a strong cross-system pattern with cropland cover (a surrogate for nonpoint-source nutrient loss from agricultural watersheds) but not with an index of hydraulic flushing rate. Cropland accounted for variation in TP in the Ozarks (51%) and TN in all 3 regions (Ozarks 58%, Plains 41%, Iowa 27%). Flushing accounted for variation in TP in the Missouri Plains (49%) and Iowa (29%). Our models suggest large-scale nutrient reduction will require massive changes in land cover to reduce nutrient input. In the Missouri Plains, for example, reducing cropland from 60% to 30% reduces TP and TN by only about 20% when other factors are held constant. Hydrology places added limits on reducing reservoir nutrients; consistent with theory, TP values in Missouri Plains reservoirs effectively double between flushing rates of 0.25 and 2 at any given cropland value. Dramatic nutrient reduction in these reservoirs is unlikely, and the influential role of hydraulic flushing adds additional management challenges for compliance with regional nutrient criteria. The analyses suggest hydrology must be considered when setting nutrient criteria, and it would be unreasonable to establish criteria based on water bodies with long retention time and apply them to rapidly flushed lakes. |
| Drivers of change for lakewater clarity | Lawrence A. Baker; Johanna E. Schussler; Stephanie A. Snyder | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 30 - 40 | Drivers of change for lakewater clarity | Lakes in the Upper Midwest have undergone extensive lakeshore development over the past 30 years, raising concerns about eutrophication. We examined 11 case study lakes in Minnesota that had undergone substantial shoreline development over the past 30 years to evaluate drivers of change in clarity. Relationships between current Secchi disk transparency (SDT) and the density of permanent equivalent houses (PEHs) and between change in SDT and change in density of PEHs were not statistically significant. For lakes with large watershed area-to-lake area (WSA: LA) ratios, modeled worst-case scenarios for impacts of shoreline housing show that phosphorus (P) inputs may not be sufficient to reduce SDT. For sensitive lakes, improved P management policies may counteract increased shoreline development, at least in part. For lakes with large WSA:LA ratios, activity outside the shoreline area, particularly agricultural activity, is probably more important than shoreline development in affecting SDT. Although policies considered “lake management†operate at fairly small scales, drivers of change in SDT operate at various temporal and spatial scales, from household to global. |
| Lake management (muck removal) and hurricane impacts to the trophic state of Lake Tohopekaliga, Florida | Mark V. Hoyer; Roger W. Bachmann; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 57 - 68 | Lake management (muck removal) and hurricane impacts to the trophic state of Lake Tohopekaliga, Florida | Lake Tohopekaliga is a large (surface area 9,800 ha) and shallow (mean depth 2.1 m) natural lake in central Florida. Cultural eutrophication and lake water level stabilization led to accelerated growth of invasive native and non-native aquatic macrophytes, resulting in the buildup of thick deposits of organic matter along the shoreline. Those shoreline areas were often devoid of oxygen, and the muck buildup filled feeding grounds for wading birds and spawning fish. Muck build up has also reduced aesthetics and boat access. To remove organic accumulation, the lake water level was dropped and heavy equipment was used to scrape the plants and dead organic materials from the underlying sand substrates from more than 1,420 ha of the littoral zone. Most of this material was heaped into large piles in shallow parts of the lake to form 29 artificial islands with basal areas from 0.4 to 3.3 ha each. Our study was designed to determine: (1) amount of nutrients stored in islands relative to annual inflows, (2) nutrient release to the lake from the islands, and (3) changes in lake trophic state due to the muck scraping and construction of the islands. The lake enhancement project was completed in late summer 2004, and the average thickness of organic materials in the scrapped areas was reduced from 46 cm to 1.6 cm, improving access and aesthetics tremendously. The islands stored several times the annual inflow of total phosphorus (TP, 3.1 times) and Total Nitrogen (TN, 6.5 times) and thus could potentially affect the lake's trophic state by leaching nutrients. Our study of water quality in the vicinity of the islands indicates that the islands had no statistically significant impact on the water chemistry of the lake through leaching of nutrients. In the 2 years following the muck removal, substantial increases in average TP (39%), chlorophyll (56%), and color (53%) and a decline in dissolved oxygen (-10%) were found in open water stations. An unintended complication to our experimental design was the occurrence of 3 major hurricanes with high winds and heavy rainfalls that passed over the Lake Tohopekaliga area immediately following the muck removal project. To account for the effects of hurricane activity we examined monthly TP, TN, chlorophyll, Secchi depth data, and quarterly color values measured for 55 relatively small (median surface area 33 ha), nearby lakes. Our sample of 55 nearby lakes showed significant increases in TP (8.2%), TN (4.1%), chlorophyll (20.1%), and water color (23.8%), and decreases in Secchi depth (-8.2%) coinciding with the passage of the hurricanes. Additionally, data from a larger control lake (Kissimmee, surface area 19,800 ha) located 10 km south of Lake Tohopekaliga showed a much larger increase in total phosphorus (66%). Therefore, some or possibly all of the differences we measured before and after scraping could have been the result of low quality water (high nutrients and organic color) flushed into the lake following the heavy rains (93 cm in August and September of 2004) accompanying the storms. The effects of muck removal cannot be completely separated from those of hurricanes because they both occurred at the same time. However, aquatic plant (Florida Department of Environmental Protection) and water chemistry (Florida Fish and Wildlife Conservation Commission) data collected after this project was completed show that submersed aquatic macrophytes in Lake Tohopekaliga have returned and total phosphorus and chlorophyll concentrations are down to levels measured prior to muck scraping and hurricane impacts. Thus, the changes in water chemistry caused by muck removal and/or the hurricanes were relatively short lived (approximately 2 years). |
| Insights for the structure of a reservoir turbidity model from monitoring and process studies | Steven W. Effler; David M. O'Donnell; David A. Matthews; MaryGail Perkins; Susan M. O'Donnell; Rakesh K. Gelda; Anthony R. Prestigiacomo; Feng Peng; David G. Smith; Andrew P. Bader; James D. Mayfield | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 69 - 86 | Insights for the structure of a reservoir turbidity model from monitoring and process studies | An array of in situ and laboratory measurements were made and in situ settling velocity experiments were conducted to support identification of model structure features necessary to simulate transient turbidity impacts in Schoharie Reservoir, NY, from runoff events. The program included: (1) extended deployments of recording instruments measuring temperature (T) and specific conductivity (SC) in the primary tributary and the reservoir surface waters; (2) automatic sampling of the tributary during runoff events for laboratory turbidity (Tn) measurements; (3) collection of vertically detailed profiles of T, SC, and the beam attenuation coefficient at 660 nm (c660; a surrogate of Tn) at multiple sites along the longitudinal and lateral axes of the reservoir with rapid profiling instrumentation; (4) chemical and morphometric characterizations of individual particles from the tributary and reservoir during dry weather conditions and for a runoff event with scanning electron microscopy coupled with automated image analysis and X-ray microanalysis (SAX); and (5) in situ measurements of settling velocity (SV) as a function of particle size with a LISST-ST®. A strong positive relationship between Tn, associated primarily with clay minerals, and tributary flow (Q), and a negative relationship between SC and Q, were reported. The entry of the primary tributary as a plunging turbid density current because of its lower T, and associated spatial and temporal patterns in c660 and SC imparted in the reservoir, were documented for two runoff events. SC was identified as a viable tracer of the movement of density currents in the reservoir, and the internal contribution of resuspension to c660 levels was depicted. The results of SAX analyses demonstrated a substantial fraction (i.e., 30-40%) of the Tn that enters the reservoir from the primary tributary was associated with particles >9.1 μm in diameter that do not contribute to Tn levels in the lacustrine portions of the reservoir. Higher SV values were observed for larger particles, but were much lower than Stokes Law conditions, suggesting that they existed as aggregates. The monitoring and SV experiment results were considered within the context of the structural needs of turbidity models, for two levels of complexity, to simulate the transient impacts of runoff events on the reservoir. A two- or three-dimensional transport submodel will be necessary to represent spatial patterns, and a kinetics submodel will need to represent (either implicitly or explicitly) size dependent settling, particle coagulation, and sediment resus-pension. |
| Application of a nutrient-saturation concept to the control of algal growth in lakes | William M. Lewis Jr.; James F. Saunders III; James H. McCutchan Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 41 - 46 | Application of a nutrient-saturation concept to the control of algal growth in lakes | Either phosphorus or nitrogen can be responsible for nutrient limitation of algae in lakes. Nitrogen limitation can be defeated by heterocystous cyanobacteria through nitrogen fixation, but no comparable mechanism exists for P. Therefore, P is considered the predominant factor limiting phytoplankton biomass in lakes. Even so, increasing numbers of studies show that many lakes are limited by N deficiency because heterocystous cyanobacteria do not become sufficiently abundant to offset N deficiency. Where N limitation prevails, P control over phytoplankton populations can be achieved only if P concentrations are first reduced to a saturation threshold that is determined by the amount of available N. The extent of this reduction, which will typically occur without any suppression of phytoplankton biomass, can be estimated from nutrient chemistry, nutrient enrichment experiments, and information on the stoi-chiometry of phytoplankton, as illustrated with data for a Colorado reservoir in which a reduction of N of about 50% would be necessary to induce P limitation. Analysis based on stoichiometry could allow managers of water quality in lakes to anticipate the implications of N limitation for P-based management of water quality. |
| Watershed management in north Florida: public knowledge, attitudes and information needs | Mallory M. McDuff; Gary S. Appelson; Susan K. Jacobson; Glenn D. Israel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 24 | 1 | 2008 | 47 - 56 | Watershed management in north Florida: public knowledge, attitudes and information needs | Water management policies in Florida emphasize the need for public involvement in managing watersheds, yet little is known about the environmental literacy of key stakeholders - nearby residents and recreational user groups. A mail survey was conducted to assess public environmental knowledge, attitudes, and information needs about watershed management based on a stratified random sample of 700 households in the 1683-km2 Orange Creek Basin in Florida. Most respondents had limited knowledge of the local environment and limited awareness of the local watershed as a landscape feature. Consumptive resource-users (e.g., anglers and hunters) had more knowledge of surface water features than non-consumptive users or non-users. Respondents generally held positive attitudes toward overall ecosystem management objectives. Attitudes toward specific management activities, such as aquatic plant control to improve boating access, differed among groups. Most respondents wanted to learn more about local ecology and preferred to obtain information about the local environment from television, newspapers, and direct mail. Consumptive users preferred to receive information from fish camps and sporting clubs, while non-consumptive users preferred to receive information from nature parks. On-site interpretive programming is needed throughout the basin, along with mass media outreach, to increase public knowledge of and support for sustainable watershed management. |
| Decline of springtime abundance of the pileworm Neanthes succinea in relation to hydrographic conditions at the Salton Sea, California | Deborah M. Dexter; Joan S. Dainer; Paul M. Detwiler; Marie F. Moreau; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 570 - 581 | Decline of springtime abundance of the pileworm Neanthes succinea in relation to hydrographic conditions at the Salton Sea, California | The Salton Sea is the largest lake in California, and its most abundant macroinvertebrate is the pileworm (Neanthes succinea: Polychaeta). This is a major dietary item for three of the four most abundant fish species in the lake, and for at least one waterbird, the eared grebe (Podiceps nigricollis). Pileworm abundance in April 2004 was monitored at depths of 2, 6 and 10 m on seven transects distributed around the perimeter of the lake. Temperature and oxygen showed marked stratification with depth. Densities were compared to those observed in April 1999. Abundances at 2 m stations were similar to those in 1999; however, densities were greatly reduced at 6 and 10 m stations compared to 1999. The development of hypoxic or anoxic bottom conditions apparently occurred earlier in the spring in 2004 than in 1999. This was the most likely cause for the low densities at 6 and 10 m. Worm densities were higher at sites with coarser sediments (sand and/or barnacle shell debris), and lowest at 2 m sites near or downstream of freshwater inflows and at 10 m where near anoxic conditions prevailed. In March 2005, a sampling of 74 stations at depths ranging from 1 m to 10 m all around the perimeter of the lake found only a single pileworm. It was evident that the lake had just turned over and that sulfide levels were very high and had probably killed off most pileworms and many other organisms as well. |
| Selenium, arsenic, DDT and other contaminants in four fish species in the Salton Sea, California, their temporal trends, and their potential impact on human consumers and wildlife | Marie F. Moreau; Janie Surico-Bennett; Marie Vicario-Fisher; Russell Gerads; Richard M. Gersberg; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 536 - 569 | Selenium, arsenic, DDT and other contaminants in four fish species in the Salton Sea, California, their temporal trends, and their potential impact on human consumers and wildlife | A summary of all existing information gathered since 1980 on contaminants in bairdiella (Bairdiella icistia), orangemouth corvina (Cynoscion xanthulus), and sargo (Anisotremus davidsonii) living in the Salton Sea is presented. Comparisons are made with an earlier analysis of contaminants in tilapia (Oreochromis mossambicus x O. urolepis hornorum hybrid). Risks are assessed for humans and piscivorous birds consuming these fish and for the health of the fish populations themselves. Of the 17 trace elements, 42 organic pesticides and 48 polychlorinated biphenyls (PCBs) sampled in whole-body and fillet samples of fish collected from the Salton Sea, only arsenic (As), selenium (Se), total DDT (tDDT), and total PCBs (tPCBs) were determined to be of potential concern for the health of human consumers. Recent average concentrations of total As in fillet tissue are 1.3 μg g-1 wet weight (ww) for bairdiella and 1.2 μg g-1 ww for corvina and tilapia, respectively, with the inorganic As fraction representing 0.3-0.4 percent of total As. Based on U.S. Environmental Protection Agency (U.S.EPA) guidelines, these levels do not pose a threat of non-cancer adverse health effects in anglers, but consumption of 360 g (13 oz) of bairdiella, 650 g (23 oz) of corvina, or 540 g (19 oz) of tilapia per week for 70 years would increase the upper bound cancer risk by 1 per 100,000 consumers exposed. Between 1997 and 2002, total As levels in these three species increased an average of ~22 percent per year. Recent geometric mean Se concentrations were 2.9, 2.8, 2.2 and 1.7 μg g-1 ww in fillet tissues of bairdiella, corvina, sargo, and tilapia, respectively. These levels were not found to present unacceptable risk for adverse health effects for adult anglers consuming up to 492 g (17 oz) of bairdiella, 571 g (20 oz) of corvina, 754 g (27 oz) of sargo, or 1000 g (35 oz) of tilapia per week, even when additional intakes of Se from other food items are taken into account. However, during 1997-2000, Se levels in at least corvina and tilapia may have been increasing by an average of ~16 percent per year though they still were lower than 20 years earlier. tDDT (mostly DDE) and PCBs were recently detected in all fish samples. Compared to screening values proposed by the U.S. EPA, these concentrations seem unlikely to cause adverse health effects in anglers consuming less than 70 g of Salton Sea fish per week, but the potential for endocrine disruptive effects warrants further study. tDDT levels have declined by ~50 percent between the early 1980s and the 1990s in bairdiella, corvina and tilapia, paralleling declines in tDDT levels in eggs of fish-eating birds at the Salton Sea. Salton Sea sportfish may be safer for human consumption than was previously thought, but these conclusions are strongly affected by the particular parameter values and assumptions used in risk analyses. Given the strong temporal trends documented for key contaminants in this changing and geochemically unusual lake, risk assessments can also become quickly out of date. Se concentrations may be elevated enough to negatively affect fish health or reproduction as well as the immune systems of piscivorous birds feeding on the fish. Levels of other contaminants in fish were not found to be of concern for birds, but given the paucity of recent analyses on whole fish, additional analyses would be deisrable. Rising salinity caused all these fish species except for tilapia to become extinct in the lake by 2003. If and when fish populations are reestablished, new asessements of contaminant levels and risks should be undertaken immediately. |
| Ciliate plankton dynamics and survey of ciliate diversity in the Salton Sea, California, 1997-1999 | Mary A. Tiffany; Brandon K. Swan; Glenn F. Gebler; Jeffrey C. Cole; Maria R. González; Kristen M. Reifel; James M. Watts; Eugene B. Small; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 606 - 619 | Ciliate plankton dynamics and survey of ciliate diversity in the Salton Sea, California, 1997-1999 | Planktonic ciliates and other protozoa were monitored at mid-lake stations in the saline, polymictic Salton Sea during the period 1997-1999, at approximately two-week intervals. Additionally, in 1999, a survey of ciliate diversity in a variety of microhabitats was undertaken. Ciliates generally comprised < 20 percent of the total zooplankton biovolume, with copepods, rotifers and larvae of a barnacle and polychaete worm making up the rest. However, in early 1999 tintinnids constituted ~40 percent of total zooplankton biovolume, and in September 1998 when metazooplankters were very scarce, ciliates represented nearly 100 percent. An anaerobic ciliate, Sonderia sp., invaded the mid-water column during periods of anoxia and high sulfide levels in 1998 and 1999. Large ciliates, such as Condylostoma spp. and Favella sp. increased in abundance over the three-year period while the smaller forms, mostly scuticociliates, did not. This pattern may be due to a decrease during our study in abundance of the filter-feeding hybrid tilapia (Oreochromis mossambicus x O. urolepis honorum), which may have selectively grazed upon the larger forms. An inverse relationship between copepod abundance and large ciliate abundance suggests copepods also prey on the larger forms. A total of 143 ciliate taxa were found as well as protozoans in other groups such as heliozoans and choanoflagellates. |
| Phytoplankton dynamics in the Salton Sea, California, 1997–1999 | Mary A. Tiffany; Maria R. González; Brandon K. Swan; Kristen M. Reifel; James M. Watts; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 582 - 605 | Phytoplankton dynamics in the Salton Sea, California, 1997-1999 | The dynamics of phytoplankton populations in the Salton Sea were studied over the 3-year period 1997-1999. Dino-flagellates were important components, often contributing over 80% of the total biovolume of cells larger than 5 μm. Gyrodinium uncatenum along with a similar, but rarer species Gyrodinium instriatum, was the most dominant taxon, present year-round, and became especially abundant in spring and summer. Diversity of dinoflagellates was high with three or four species often co-occurring with similar densities. The largest dinoflagellate, Gonyaulax grindleyi (= Protoceratium reticulatum), increased greatly in abundance during 1997-1999. Diatoms co-dominated year round with the colonial araphid Thalassionema sp. also becoming especially abundant in 1999. During the winter mixing period, diatom populations often were dominated by pennate species usually considered benthic, such as Pleurosigma ambrosianum, Ceratoneis closterium and Tryblionella punctata. Cryptomonads, represented by several species, were usually numerous and, although relatively small, constituted as much as 20-30% of total phytoplankton biovolume. A raphidophyte, Chattonella marina, reported to be ichthyotoxic in other locales, was abundant in summer, comprising about a third of total phytoplankton biovolume then and reaching mid-lake densities of nearly 1,500 cells ml-1. Two colonial non-motile green algae were usually present; one of these, Crucigenia rectangularis, increased greatly in density in 1999. A euglenoid, Eutreptia lanowii, was highest in density in summer when it contributed about 5-10% of total biovolume at times after other species were reduced by sulfide events. Filamentous planktonic cyanobacteria were very rare. The increase in large species of phytoplankton over the three-year period coincided with a dramatic decrease in abundance of a planktivorous fish, the Mozambique mouthbrooder (Oreochromis mossambicus x O. urolepis honorum), which likely was responsible for these changes in phytoplankton composition. Phytoplankton biovolume densities and chlorophyll a concentrations each year were highest, 6-16 mm3 l-1 and 30-40 μg 1-1 respectively, in the spring. In summer and early fall, occasional windstorms mixed the water column causing sulfide-laden bottom waters to upwell and strip surface waters of oxygen. Sharp drops in abundance of most phytoplankton species occurred during these events presumably due to poisoning by hydrogen sulfide. Satellite images confirm the presence of large patches of high albedo surface waters at these times, lasting days to over a week, produced by backscattering from abundant crystals of gypsum produced following oxidation of hydrogen sulfide to sulfate. |
| Stratification, sulfide, worms, and decline of the Eared Grebe (Podiceps nigricollis) at the Salton Sea, California | Thomas W. Anderson; Mary Ann Tiffany; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 500 - 517 | Stratification, sulfide, worms, and decline of the Eared Grebe (Podiceps nigricollis) at the Salton Sea, California | Over the last half century the Salton Sea has been an important migratory stopover site for the Eared Grebe (Podiceps nigricollis). However, in recent years there have been sporadic mass mortalities (i.e., 150,000 in 1992) and a great reduction in the number of grebes visiting during the winter. We propose that a worsening food supply is causing the decline and that starvation may be a major cause of the unexplained mortalities. While at the Sea, grebes forage almost exclusively on a benthic polychaete, the pileworm (Neanthes succinea). This resident pileworm population has increasingly been subject to periodic crashes driven by exposure to anoxic, sulfide rich, hypolimnetic water following lake mixing events. A set of interlocking mechanisms seem to be operating. These involve, in particular, increasing lake salinity, weather events favoring lake stratification, and booms and busts in tilapia (Oreochromis mossambicus O. urolepis hornorum) and plankton populations, including those of toxic cyanobacteria. In spring, Eared Grebes arrive from the Gulf of California and many arrive in need of food to fuel the remainder of their migration. When pileworms are scarce, many grebes are able to continue on toward their northern breeding grounds, but those that lack sufficient energy stores are forced to stay and may eventually perish. This analysis is surely incomplete, and definitive explanations of the excessive drinking and waterlogged plumage often exhibited by Eared Grebes during mass dieoffs have yet to be found. |
| Fish and fish-eating birds at the Salton Sea: a century of boom and bust | Allen H. Hurlbert; Thomas W. Anderson; Kenneth K. Sturm; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 469 - 499 | Fish and fish-eating birds at the Salton Sea: a century of boom and bust | We reconstruct historical trends in both fish and fish-eating bird populations at the Salton Sea, California since the Sea's formation in 1905. The fish community has undergone dramatic shifts in composition, from freshwater species present in the initial wash-in to stocked marine species to dominance by an unintentionally introduced cichlid. Historical catch records, creel censuses, and gill-netting studies suggest that total fish biomass in the lake increased dramatically throughout the 1970s, crashed in the late 1980s, recovered in the mid-1990s, and crashed again in the early 2000s. We speculate that crashes in fish populations are primarily due to three physiological stressors—rising salinity, cold winter temperatures, and high sulfide levels and anoxia associated with mixing events. The trends in fish biomass are mirrored in population trends of both breeding and wintering fish-eating birds, as indexed by a number of independent bird surveys. In contrast, most non-piscivorous birds at the Salton Sea show no indication of these temporal dynamics. We discuss possible explanations for the observed trends in fish-eating bird populations, including decline in organochlorine insecticide use and fluctuations in prey abundance at the Salton Sea. Finally, we speculate on the future prospects of both fish and fish-eating birds at the Salton Sea given the environmental challenges the Sea currently faces. |
| Length-weight relations and growth rates of dominant fishes of the Salton Sea: implications for predation by fish-eating birds | Ralf Riedel; Lucille M. Caskey; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 528 - 535 | Length-weight relations and growth rates of dominant fishes of the Salton Sea: implications for predation by fish-eating birds | The Salton Sea is the largest lake in California. Inflows are primarily from agricultural runoff, which render it eutrophic and able to support extensive fisheries. The lake and its surrounding wetlands are critical links for the Pacific Flyway, providing refuge and food for an extensive and diverse avifauna. We document fish size distributions, body shapes and growth rates and consider how they determine availability of fish to birds. Tilapia (Oreochromis mossambicus x O. urolepis hornorum) is the most important resource for fish-eating birds. Tilapia grow fast to a size that is readily handled by large birds and are the most abundant fish in the lake. Bairdiella (Bairdiella icistia) grow to a smaller size over a longer period. Corvina (Cynoscion xanthulus), sargo (Anisotremus davidsoni), and shad (Dorosoma cepedianum) are less important for fish-eating birds because they quickly grow to sizes outside bird handling capabilities (corvina) or are not readily catchable and currently of low abundance (shad and sargo). Shape, in particular girth, determines the weight of the largest individual fish that a bird can handle; a slender 1,000 g corvina, for example, being more easily ingested than a deeper-bodied 1,000 g tilapia. Shape, however, is of secondary importance to growth rate in determining importance of a fish species in a bird's diet. Predation by corvina on tilapia and other smaller species may have historically played a large role in determining availability of fish to fish-eating birds. |
| Coping with multiple stressors: physiological mechanisms and strategies in fishes of the Salton Sea | Brian A. Sardella; Victoria Matey; Colin J. Brauner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 518 - 527 | Coping with multiple stressors: physiological mechanisms and strategies in fishes of the Salton Sea | Saline lakes are found around the world, typically within inland drainage basins that lack outflow. While fish species in these lakes are not numerous, the Salton Sea in southeastern California, USA, supports several species and a substantial recreational fishery. The Salton Sea was formed in 1905, and since its formation, the salinity has varied greatly, and is currently approaching 44 g/l. The Salton Sea presents several environmental challenges to fishes that inhabit it, especially high salinity, large variations in temperature, and high levels of calcium and sulphate. Studies investigating the osmoregulatory ability of the California Mozambique tilapia (Oreochromis mossambicus x O. urolepis hornorum), the dominant species in the Salton Sea, indicate that they can tolerate salinities up to 65 g/l at 25 °C with minimal effects on osmoregulatory status. However, a reduction in temperature to 15 °C or an increase to 35 °C (both within the range of temperature observed in the Salton Sea) greatly reduce the salinity tolerance of this species. These data indicate that the seasonal winter kills of California Mozambique tilapia are likely associated with a direct effect of temperature on salinity tolerance at the current salinity of the Salton Sea. In this review we explore these environmental stressors and their effects on fish, particularly within the context of the Salton Sea fishery, and discuss how euryhalinity may give tilapia an advantage over the other Salton Sea species with respect to surviving the dynamic environment. |
| Dramatic blooms of Prymnesium sp. (Prymnesiophyceae) and Alexandrium margalefii (Dinophyceae) in the Salton Sea, California | Mary Ann Tiffany; Jennifer Wolny; Matthew Garrett; Karen Steidinger; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 620 - 629 | Dramatic blooms of Prymnesium sp. (Prymnesiophyceae) and Alexandrium margalefii (Dinophyceae) in the Salton Sea, California | In early 2006, unusual algal blooms of two species occurred in the Salton Sea, a large salt lake in southern California. In mid-January local residents reported bioluminescence in the Sea. Starting in February, large rafts of long-lasting foam, also bioluminescent, were observed as well. Microscopy investigations on water and sediment samples collected in March showed the marine dinoflagellate, Alexandrium margalefii, and the prymnesiophyte, Prymnesium sp., both previously unreported in the Salton Sea, to be abundant. Bioluminescence and foam production continued through March. Other dinoflagellate species, recorded during earlier studies, were rare or not detected during these blooms. Despite the fact that many Alexandrium species are known paralytic shellfish poison (PSP) producers, preliminary saxitoxin tests on this population of A. margalefii were negative. Previous reports on A. margalefii do not mention bioluminescence. It appears that the foam was caused by the Prymnesium sp. bloom, probably via protein-rich exudates and lysis of other algal cells, and its glow was due to entrained A. margalefii. This is the first report of A. margalefii in U.S. waters and the first report of it in a lake. |
| History of eutrophic lake rehabilitation in North America with arguments for including social sciences in the paradigm | G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 323 - 329 | History of eutrophic lake rehabilitation in North America with arguments for including social sciences in the paradigm | The brief history of management and rehabilitation of eutrophic lakes and reservoirs in North America has gone in 4 directions: (1) solving the limiting nutrient controversy; (2) testing in-lake and watershed rehabilitation methods; (3) examining the roles of biology in determining lake trophic state; and (4) involving lake users and owners in lake research and management. Two major outcomes have been reached: (1) a great increase in understanding of eutrophication, its impacts on humans, and its solutions; and (2) major developments in understanding lake and reservoir ecology through a holistic rather than reductionist research model. Diversion and/or control of point and nonpoint sources of nutrients, silt, and organic matter, including internal nutrient recycling, were shown as necessary to lake improvement, but eutrophication problems often continue or return because social, political, and economic forces can thwart treatment effectiveness and longevity. An example is the “American Diet†that drives agricultural pollution of freshwater. The lake management and rehabilitation process should incorporate social scientists into its paradigm so that we can learn how to encourage humans to make choices and have behaviors better suited to successful longterm lake protection and management. |
| Preface | Richard C. Lathrop | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 321 - 322 | Preface | |
| Perspectives on the eutrophication of the Yahara lakes | Richard C. Lathrop | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 345 - 365 | Perspectives on the eutrophication of the Yahara lakes | Eutrophication of the four Yahara lakes—Mendota, Monona, Waubesa, and Kegonsa—near Madison, Wisconsin, has been dramatic since the mid-1800s. For Lake Mendota, the erosion of sediments from higher water levels established by the damming of the lake's outlet, plus the agricultural expansion of its watershed, resulted in blue-green algal growths. These impacts, however, were dwarfed by water quality problems stemming from Madison's wastewater inputs that directly entered Lake Monona from the late 1800s through 1936, and then Lake Waubesa until 1958. Blue-green algal blooms were so bad in the lower Yahara lakes that the Madison Public Health Department conducted major copper sulfate treatments during 1925-1954. During the wastewater input years, inorganic nitrogen (N) and especially dissolved reactive phosphorus (DRP) concentrations in the surface waters were very high (particularly in Waubesa and Kegonsa), indicating neither nutrient was limiting algal growth. No P legacy from the wastewater inputs was found in Waubesa and Kegonsa's sediments; minimal P-binding potential due to low iron (Fe) availability is the hypothesized reason. Mendota's algal blooms were not a problem until the mid-1940s when wastewater inputs from upstream communities increased as well as the agricultural use of N and P fertilizers. This increase in eutrophication symptoms coincided with an increase in indices of DRP and inorganic N concentrations in the lake. After wastewater diversion in 1971, blue-green algal blooms persisted in Lake Mendota, and the onus of the problem shifted to agricultural and urban nonpoint source pollution. While much progress has been made in recent years to control these pollution sources to Mendota, manure runoff during late winter continues as a management problem. As evidence, P loadings during January to March constituted 48% of total loadings measured for 1990-2006 in the Yahara River subwatershed. Much of this runoff P was dissolved and not associated with high sediment loads, whereas during other months, more of the runoff P was bound to sediments that could settle out in lower stream reaches prior to entering the lake. However, low P-binding potential of recently deposited sediments in Mendota along with signs of water quality improvements following periods of drought indicate the lake could respond rapidly to nutrient input reductions. Finally, DRP and inorganic N concentrations since 1980 have indicated that algal growth in the Yahara lakes during July-August may have been limited by not only P, but N (especially in the lower Yahara lakes). Aggressive programs to reduce inputs from both nutrients will be important to prevent scum-forming blue-green algal blooms and filamentous algal growths that could become problematic once zebra mussels become established in the Yahara lakes. |
| Perceived environmental quality and place attachment in North American and European temperate lake districts | Richard C. Stedman; Richard C. Lathrop; Bev Clark; Jolanta Ejsmont-Karabin; Peter Kasprzak; Kurt Nielsen; Dick Osgood; Maria Powell; Anne-Mari Ventelä; Katherine E. Webster; Anna Zhukova | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 330 - 344 | Perceived environmental quality and place attachment in North American and European temperate lake districts | Sense of place, or the meanings and attachments held for settings, continues to emerge as an important factor in environmental management. Previous research in a lake-rich setting in northern Wisconsin, USA, demonstrated that attachment to lakes is based in part on the perceived water quality and perceptions of social conflict. This research explores how these findings are similar or different across sites with very different ecological and social characteristics. To explore these cross-site similarities and differences, a social science survey was implemented in 10 lake districts (total n = 2,278 respondents), including 5 sites in North America and 5 in Europe. These sites share several commonalities: they all lie at fairly similar latitudes in the Northern Hemisphere, and they are all regions relatively rich in lake resources. The results demonstrate the myriad commonalities and contrasts in behaviors, environmental perceptions, and place attachment across sites. |
| Sulfide irruptions and gypsum blooms in the Salton Sea as detected by satellite imagery, 1979–2006 | Mary A. Tiffany; Susan L. Ustin; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 637 - 652 | Sulfide irruptions and gypsum blooms in the Salton Sea as detected by satellite imagery, 1979-2006 | Bright pale-green surface waters, locally called “green tides,†are visible to the naked eye and satellite sensors in patches at the Salton Sea, usually between May and November. These were studied using satellite remote sensing and by direct sampling. Algal blooms are ruled out as a cause as phytoplankton abundance, and chlorophyll concentrations were lower within the patches than in surrounding areas. The presence of abundant microscopic gypsum (CaSO4·2H2O) crystals in surface waters suggests that scattering from this precipitating salt produces the intense signals. Biogeochemical factors include: the decomposition of organic matter, resultant anoxia and production of hydrogen sulfide by sulfate-reducing bacteria at depth, and oxidation back to sulfate and precipitation of gypsum during wind-induced overturn events. Sulfide concentrations following one such event in September 2005 ranged from 0.3 to 2.7 mg 1-1 at the surface and 1.2 to 25 mg 1-1 in bottom waters. Gypsum crystals occurred at densities up to 40,000 ml-1 in surface water on that date, most 20-30 μm in length with some as long as 190 μm. From 1998 to 2006, gypsum blooms appear to have increased in intensity and duration implying an increase in sulfide irruptions and anoxia in surface waters. As much as 97 percent of the lake was affected in early summer of 2003 and 75-80 percent in summers of 2005 and 2006. Events lasted for months at a time during these years. This intensification is likely due to the decline in abundance of a planktivorous fish, a hybrid tilapia, the California Mozambique mouthbrooder, leading to increased algal productivity, more severe anoxia and higher levels of dissolved hydrogen sulfide. Gypsum blooms seem to have occurred at least as far back as the 1970s, and are associated with frequent mass mortalities of fish, plankton and benthos. |
| Diffusive flux of selenium between lake sediment and overlying water: Assessing restoration alternatives for the Salton Sea | Earl R. Byron; Harry M. Ohlendorf | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 630 - 636 | Diffusive flux of selenium between lake sediment and overlying water: Assessing restoration alternatives for the Salton Sea | Elevated concentrations of selenium are a concern for humans and wildlife at the Salton Sea, a large salt lake in the desert of southeastern California. As the lake is highly eutrophic and has become too saline for most fish, various restoration alternatives have been proposed. These would alter the water quality, volume, depth, and surface area of the Salton Sea and possibly create new aquatic habitats. Such changes are likely to alter conditions at the sediment-water interface that could influence the release or storage of selenium in the surficial, most bioavailable layers of lake sediment. A 5-day, 23 factorial laboratory experiment using intact cores of lake sediment with overlying lake water documented effects of dissolved oxygen level (oxic, anoxic) and salinity (2, 20, 35 g/L) on selenium flux. Higher positive flux from sediments into water was observed under oxic conditions and at the lowest salinity values. Selenium flux from the water to the sediment dominated at salinities of 20 and 35 g/L. Dissolved selenite (SeIV) and organic selenium compounds predominated in the overlying water. Results imply that selenium in overlying water is likely to be sequestered to the sediment under future highly saline conditions, as it is today, but may be released into the overlying water if its salinity is very low or if oxygenation is enhanced over current conditions. |
| Assessment of internal and external lake restoration measures for two Berlin lakes | Inke Schauser; Ingrid Chorus | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 366 - 376 | Assessment of internal and external lake restoration measures for two Berlin lakes | Two previously highly eutrophic lakes, Lake Tegel and Schlachtensee in Berlin, Germany, were subjected to similar external but different internal restoration measures during the last 20-25 years. External phosphorus (P) load was reduced in both lakes by P-stripping their main inflows using P-elimination plants; internal P load was treated by aeration in Lake Tegel and by hypolimnetic withdrawal in Schlachtensee. Loads before and after treatment are compared with the targets using the Vollenweider model and a modified One-Box model. The results indicate that external load reduction was the main cause of the pronounced lake water quality improvements. The hypolimnetic withdrawal in Schlachtensee was effective only in the initial years. No significant positive effect can be identified for the aeration of Lake Tegel. |
| Spatial and temporal patterns of transparency and light attenuation in the Salton Sea, California, 1997–1999 | Brandon K. Swan; Kristen M. Reifel; Mary Ann Tiffany; James M. Watts; Stuart H. Hurlbert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 653 - 662 | Spatial and temporal patterns of transparency and light attenuation in the Salton Sea, California, 1997-1999 | Transparency, as measured by Secchi disk depth (SD), and light attenuation (Kd(PAR)) were measured in the Salton Sea in 1997-1999. Linear regression models were used to evaluate the relative importance of phytoplankton and non-phytoplankton substances in determining SD and Kd(PAR). Paired measurements of SD and Kd(PAR) made in 1999 were used to track relative changes in the importance of light absorption and scattering processes. Phytoplankton biomass was a poor predictor of both SD and Kd(PAR) at mid-lake stations, and this is most likely due to high concentrations of non-phytoplankton substances such as inorganic particulate matter in the Salton Sea. During strong windstorms in the warmer part of the year, the upper water column mixes with hydrogen sulfide-laden bottom waters, causing large crashes in plankton populations. This previously reported phenomenon also strongly affects the light regime through the production of gypsum crystals, which scatter large portions of penetrating light. Since a large amount of variation in both SD and Kd(PAR) is not explained by phytoplankton biomass, any use of this relationship to forecast future changes in water clarity through nutrient reductions must be done with caution. |
| Preface | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 5 | 2007 | 467 | Preface | |
| Danish and other European experiences in managing shallow lakes | Erik Jeppesen; Martin Søndergaard; Torben L. Lauridsen; Brian Kronvang; Meryem Beklioglu; Eddy Lammens; Henning S. Jensen; Jan Köhler; Anne-Mari Ventelä; Marjo Tarvainen; István Tátrai | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 439 - 451 | Danish and other European experiences in managing shallow lakes | For a century eutrophication has been the most serious environmental threat to lakes in the densely populated or agricultural areas of Europe. During the last decades, however, major efforts have been used to reduce the external nutrient loading, not least from point sources. Despite these comprehensive efforts, lake eutrophication remains a major problem. Today, the highest pollution input is derived from diffuse sources mainly from agricultural land in lake catchments. We describe the actions taken to reduce the external nutrient loading and the lake responses to these actions as well as the use of additional methods to reinforce recovery, such as biomanipulation. We further discuss resilience and short and long-term responses. We highlight the Danish experiences, but add several examples from restoration measures taken elsewhere in Europe. We also briefly discuss how a potential change in climate may affect lake responses to diminished nutrient loading. |
| Perspectives on the long-term dynamics of lakes in the landscape | John J. Magnuson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 452 - 456 | Perspectives on the long-term dynamics of lakes in the landscape | Lakes are valued as a part of our “sense of place†at a very local and personal level. Yet protecting a treasured lake from unwanted change increasingly requires that we address long-term drivers acting over broad spatial scales. Global climate change and invasion of exotics, for examples, cannot be dealt with efficiently or even at all at an individual lake scale. Protecting our lake requires regional and global advocacy and action. When we do not act at these longer and broader scales we are often beset with surprises, live with problems not of our choosing, seek solutions for thousands of lakes one lake at a time, and often must live with or manage the consequences of irreversible changes. |
| Lakes and society: Mirrors to our past, present and future | Brian Moss | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 457 - 465 | Lakes and society: Mirrors to our past, present and future | Ultimately most things are connected. The lessons we learn from our arts, our literature and our science all reflect an understanding of the human lot. Ecology is concerned with systems that include humans but are dominated by other organisms. Sociology and economics are concerned with systems that include non-human organisms but are dominated by humans. Principles derived from a study of the first, it is argued, can be applied to the second (for they are both manifestations of the same thing) in an attempt to explain why we are failing to move toward a sustainable existence. A range of ideas that have emerged from ecological studies, and particularly the alternative states model of shallow lakes, is used to illuminate the current problems of human societies in relation to the global environment. |
| Lake responses to long-term hypolimnetic withdrawal treatments | Gertrud K. Nürnberg | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 388 - 409 | Lake responses to long-term hypolimnetic withdrawal treatments | Hypolimnetic withdrawal is an in-lake restoration technique based on the selective discharge of bottom water to enhance the removal of nutrients and electro-chemically reduced substances that build up when the hypolimnion becomes anoxic. Comparison of water quality variables before and during treatment in about 40 European and 8 North American lakes indicates that hypolimnetic withdrawal is an efficient restoration technique in stratified lakes. Water quality improvement was apparent in decreased summer average epilimnetic phosphorus (P) and chlorophyll concentrations, increased Secchi disk transparency, and decreased hypolimnetic phosphorus concentration and anoxia. In particular, summer average phosphorus decreases were significantly correlated with annual water volumes and P masses withdrawn per lake area, indicating the importance of hydrology and timing of the treatment. Observations as well as models revealed that avoiding extreme temperature changes in the water column is critical for a successful application of the technique. The removal of colder bottom water may increase bottom water temperatures, which not only increases sediment release rates and sediment oxygen demand but, more important, may lead to thermal instability, resulting in enhanced entrainment of nutrient-rich hypolimnetic water and increased surface eutrophication. Hypolimnetic withdrawal also improved water quality in man-made lakes with bottom outlets unless too much withdrawal led to thermal instability. It failed to have a positive effect in a shallow oligomictic lake, probably because nutrient export was not much increased. A recognized disadvantage of hypolimnetic withdrawal is its impact on downstream waters, including eutrophication, temperature increase, oxygen depletion, and odor development. In the experiences evaluated, treatment of the withdrawal water ranged from no treatment in older remote applications in the European Alps, to passive treatment in wetlands and settling ponds, and modern waste water technologies in more recent applications. Overall, hypolimnetic withdrawal is an effective low-cost restoration technique to combat and potentially reverse eutrophication in stratified lakes and reservoirs. |
| Reduction of nutrient loading and biomanipulation as tools in water quality management: Long-term observations on Bautzen Reservoir and Feldberger Haussee (Germany) | Peter Kasprzak; Jürgen Benndorf; Thomas Gonsiorczyk; Rainer Koschel; Lothar Krienitz; Thomas Mehner; Stephan Hülsmann; Heinz Schultz; Annekatrin Wagner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 410 - 427 | Reduction of nutrient loading and biomanipulation as tools in water quality management: Long-term observations on Bautzen Reservoir and Feldberger Haussee (Germany) | Long-term (1976-1999) biomanipulation in Bautzen Reservoir (BR) revealed that a combination of piscivore stocking and catch restrictions for piscivores led to the desired effects of low planktivorous fish biomass and enhanced biomass of large filter feeders (Daphnia galeata). Despite the hypertrophic status of BR, fisheries management shifted the planktivore-dominated fish community into a piscivore-dominated community. High winter (Jan-Mar) Daphnia biomass was a sensitive indicator of reduced planktivory. Although edible phytoplankton was suppressed by elevated Daphnia biomass, mean seasonal (May-Oct) total phytoplankton biomass remained unchanged due to growth of large inedible algae and cyanobacteria. Inedible and total phytoplankton biomass was primarily controlled by phosphorus availability. However, during clear water periods a reduction of total phytoplankton was achieved with drastically increased Secchi readings. In Feldberger Haussee (FH), despite intensive long-term manual removal of cyprinids (1985-2002) and stocking of piscivorous fish (1988-2002), biomanipulation only had restricted, delayed, or transient effects on the ecosystem. Mean proportion of piscivores within total yield increased but was below 20% in most years. Planktivore cyprinid yields dropped until 1990 and remained constant thereafter. Daphnia biomass slightly increased after biomanipulation became effective (1987-1989) but declined to pre-biomanipulation levels later in the experiment (1996-2005). Beginning in 1997, both edible and inedible phytoplankton biomass started to decrease. Finally, when biomanipulation had been implemented after a delay of 8 years water clarity increased significantly. Although external loading reductions and biomanipulation in both lakes resulted in moderate phytoplankton biomass reduction and Secchi depth enhancement, the reasons for the observed changes were different. Even though strong cascading effects were detected at the top of the food web in BR, the trophic cascade was largely decoupled between phyto- and zooplankton. External plus internal phosphorus loading still exceeded a critical threshold below which a top-down-induced indirect effect of phosphorus sedimentation and finally limitation could have reduced phytoplankton biomass. In constrast to BR, the critical phosphorus loading threshold in FH has probably been approached. Nonetheless, cascading effects were weak due to insufficient reduction of planktivorous cyprinids. Improved water quality was primarily a result of resource-related effects. Thus, the 2 long-term experiments reveal that (1) biomanipulation cannot be applied successfully without reducing nutrient loading below a critical threshold (BR), and (2) for successful biomanipulation, 30-40% piscivores within total fish standing stocks are required (BR and FH). Without optimum piscivory, manual removal of planktivores will hardly produce sustained cascading effects (FH). |
| Long-term management of Pyhäjärvi (southwest Finland): eutrophication, restoration – recovery? | Anne-Mari Ventelä; Marjo Tarvainen; Harri Helminen; Jouko Sarvala | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 428 - 438 | Long-term management of Pyhjrvi (southwest Finland): eutrophication, restoration - recovery? | Pyhjrvi, located in the centre of an intensive agricultural area in southwest Finland, is an example of a lake suffering from eutrophication. The lake has been intensively studied for decades and was the object of comprehensive restoration activities both in the catchment and in the lake since the 1990s. During the last 20 years the quality and general usability of water in Pyhjrvi has deteriorated due to increased algal blooms but has shown some signs of recovery during recent years. These changes have been driven by both a variety of human activities and natural climate related factors such as dry years. Pyhjrvi has been the object of intensive biomanipulation for decades, carried out by commercial fishermen, whose annual harvest rate approaches the total production of vendace (Coregonus albula), the main planktivore in Pyhjrvi. The restoration project has also subsidized the harvest of commercially unwanted fish since 1995. In 2002-2006, the EU provided funds for this fishing, which was especially intensive in 2002-2004. The main goal of the future management is to maintain and ensure the current levels of moderately low algal biomass considered acceptable by the financiers and local users of the lake. Achieving the level of water quality during the 1980s is not currently realistic due to current intensive agricultural use of the catchment, lack of cost-effective tools for load reduction from the agriculture, and climate change threats. |
| Assessment of multi-year (1956–2003) hypolimnetic withdrawal from Lake Kortowskie, Poland | Julita A. Dunalska; Grzegorz Wiśniewski; Czesław Mientki | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 4 | 2007 | 377 - 387 | Assessment of multi-year (1956-2003) hypolimnetic withdrawal from Lake Kortowskie, Poland | Hypolimnetic withdrawal as a restoration method comprises the withdrawal of the nutrient-rich hypolimnion by a pipe directly to the outlet, thus replacing the surface outflow. The method was first applied to Lake Kortowskie in 1956 and continues today. The direct effects of hypolimnetic withdrawal can be observed in the near-bottom waters during the pipe's operation (May-Sep). The treatment depends on the quantity of water withdrawn by the pipe. A high withdrawal rate increased the rate of hypolimnetic heating, diminished the water mass stability and shortened summer stagnation. Hypolimnetic withdrawal did not improve the oxygen conditions in Lake Kortowskie, although it shortened the duration of the anaerobic conditions near the bottom and diminished the spatial extent of oxygen deficiency. Increased release of phosphorus from the bottom deposits to the near-bottom water and finally the outlet via the withdrawal pipe has been observed, with a consequent impoverishment of the upper sediments. The amount of mineral phosphorus and ammonium nitrogen in the near-bottom water decreased independent of the withdrawn volume. The decrease of phosphorus and nitrogen during the pipe's operation shows that hypolimnetic withdrawal removes nutrients released from bottom deposits so that the lake becomes less enriched in nutrients. Multi-year examination has confirmed that this process is the most positive feature of this restoration method. The restoration can be optimized by maximizing nutrient export and withdrawing throughout the summer stagnation (particularly in August and September), when nutrient concentrations near the bottom are maximal |
| Assessing Fish Populations in Remote Subarctic Lakes Using Hydroacoustics | Kyle J. Hartman; F. Joseph Margraf | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 211 - 218 | Assessing Fish Populations in Remote Subarctic Lakes Using Hydroacoustics | High latitudes of North America and Asia have many unstudied small lakes. The remoteness of these lakes presents a challenge to biologists who manage these systems. At Togiak National Wildlife Refuge in Alaska we evaluated the use of mobile hydroacoustic surveys as a tool for assessing unstudied lakes and setting priorities for further study. We sampled 50-ha Hole Lake in July 2002 with a 120-kHz split-beam hydroacoustic system, completing four surveys at different times throughout daylight and darkness. Despite day-night changes in distribution of fishes in the lake we found no significant differences in relative biomass, density, or in the detection of larger fish targets that may be of importance from a fisheries management perspective. However, between-transect variability in acoustic measures was high and may have masked the ability to detect these changes. Nonetheless, a simple design bisecting the study lake that was completed in 25 min was capable of detecting fish populations of potential interest to fisheries managers. We suggest a simple design (bisecting the lake) for scanning such lakes for the presence of fish populations of interest in these remote areas. |
| Controls on algal abundance in a eutrophic river with varying degrees of impoundment (Kalamazoo River, Michigan, USA) | Nicole J. Reid; Stephen K. Hamilton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 219 - 230 | Controls on algal abundance in a eutrophic river with varying degrees of impoundment (Kalamazoo River, Michigan, USA) | This study examined how nutrients and hydraulic flushing interact to regulate growth of phytoplankton in the Kalamazoo River (Michigan, USA), which has seven reservoirs with summer residence times ranging from <1 to 12 days. The largest reservoir, Lake Allegan, suffers from eutrophication and resultant impairments of beneficial uses, problems being addressed by a TMDL focused on control of phosphorus. Water residence time was the most important control on algal growth in the various impoundments, including Lake Allegan, where residence time remained <12 days through the summer. Based on longitudinal surveys, free-flowing river reaches appeared to remove phyto-plankton, whereas a series of old decommissioned dams above Lake Allegan evidently contributed to algal biomass accumulation in the river. Nutrient concentrations were generally high throughout the river system; thus, algal growth may not be nutrient-limited at present. Phytoplankton in the two largest reservoirs was dominated by diatoms and green algae during late summer, despite nutrient concentrations that would tend to favor cyanobacteria in lakes. The relative availability of phosphorus (P), nitrogen (N), and silicon (Si) can indicate how algal growth may respond if nutrient concentrations were to decrease in the future. Nutrient ratios suggest that N and Si could be important in addition to P, depending on the reservoir and the season. In reservoirs with short water residence times, strategies to control eutrophication by reducing phosphorus loading may not yield results as readily as they do in lakes; hydraulic flushing, other nutrients, and upstream impoundments must also be considered. |
| Improved estimation of wetland cover in the western Canadian boreal forest | Kendra Couling; Ellie E. Prepas; Daniel W. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 245 - 254 | Improved estimation of wetland cover in the western Canadian boreal forest | The Alberta Wetland Inventory (AWI), which is used in a variety of applications across the province to estimate wetland cover from aerial photographs, detected only 34% of confirmed wetland field plots in boreal forest watersheds in the Swan Hills of Alberta. Given the association between wetland cover and runoff and surface water chemistry in western Canadian boreal forest (Boreal Plain) watersheds, accurate quantification of wetland cover is critical to efforts to model hydrologic processes and water quality. Therefore, as a component of the Forest Watershed and Riparian Disturbance (FORWARD) Project, the Wetland Inventory and Identification Tool (WIIT) was developed and successfully detected 81% of the wetland field plots. Application of both models across a variety of landscapes in the boreal forest of Alberta demonstrated that wetland cover estimates were 1.5 times higher with the new WIIT model than with AWI. Also, WIIT identified polygons that were both smaller and contained taller trees than those identified by AWI, indicating that this computer model may be more effective than wetland identification methods that use only aerial photography. Results of this study show that careful interpretation of aerial photographs at the 1:15,000 scale, coupled with ground truthing and computer models, can provide an accurate means of identifying wetlands on Boreal Plain landscapes. |
| Turbidity and suspended solids levels and loads in a sediment enriched stream: implications for impacted lotic and lentic ecosystems | Anthony R. Prestigiacomo; Steven W. Effler; David O'Donnell; James M. Hassett; Edward M. Michalenko; Zhongping Lee; Alan Weidemann | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 231 - 244 | Turbidity and suspended solids levels and loads in a sediment enriched stream: implications for impacted lotic and lentic ecosystems | The implementation of an automated stream monitoring unit that features four probe-based turbidity (Tn) measurements per hour and the capability to collect frequent (e.g., hourly) samples for total suspended solids (TSS) analyses during runoff events to assess the dynamics of Tn, TSS and corresponding loads in sediment-rich Onondaga Creek, NY, was documented. Major increases in both Tn (maximum of 3,500 NTU) and TSS (maximum of 1630 mg/L) were reported for the stream during runoff events. Relationships between Tn, TSS and stream flow (Q) were developed and applied to support estimates of TSS loading (TSSL). Tn was demonstrated to be a better predictor of TSS than Q, supporting the use of the frequent field Tn measurements to estimate TSSL. During the year of intensive monitoring, 65% of the TSSL was delivered during the six largest runoff events that represented 18% of the annual flow. The high Tn levels and extensive in-stream deposition have negatively impacted the stream's biota and the esthetics of a downstream harbor. Onondaga Creek is reported to be the dominant allochthonous source of inorganic particulate material to downstream Onondaga Lake. These sediment inputs have important implications for the lake, within the context of two on-going rehabilitation programs aimed at contaminated lake sediments and the effects of extreme cultural eutrophication, by contributing substantially to sedimentation and turbidity. A satellite image documented the occurrence of a conspicuous turbidity plume that emanated from Onondaga Creek following a minor runoff event, suggesting such an effect is common and that related impacts are not spatially uniform. |
| Evaluation of aquatic macrophyte community response to island construction in the Upper Mississippi River | Heidi A. Langrehr; Brian R. Gray; Jeffrey A. Janvrin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 313 - 320 | Evaluation of aquatic macrophyte community response to island construction in the Upper Mississippi River | Impounding large rivers has often led to reductions in aquatic habitat diversity over time. One approach used to restore habitat on the Upper Mississippi River is island construction. A specific purpose of island construction is to increase the growth and diversity of aquatic macrophytes. We addressed whether this purpose was met for islands constructed in a reach of the Upper Mississippi River. Aquatic macrophyte levels and richness around 2 constructed island complexes were compared with those in open water reference areas in 1998 and 2000. These data suggest that macrophyte levels increased in the construction area relative to the reference area for the second but not the first island complex. Findings were similar for both percent frequency of occurrence and richness index models. These differences in response are attributed to the differing maturities of the 2 island complexes. The first complex was completed 6 years prior to the initiation of aquatic macrophyte sampling, whereas sampling began midway through the construction phase of the second complex. The response of aquatic macrophytes in the first island complex may have stabilized prior to sampling, whereas aquatic macrophyte responses to construction of the second island complex were partially captured during the sampling period. These findings suggest that island construction positively influences aquatic macrophyte levels in impounded reaches of large rivers. |
| Application of a steady-state nutrient model and inferences for load reduction strategy in two public water supply reservoirs in eastern Connecticut | Farhad Nadim; Amvrossios C. Bagtzoglou; George E. Hoag; Fred L. Ogden; Glenn S. Warner; David M. Soballe | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 264 - 278 | Application of a steady-state nutrient model and inferences for load reduction strategy in two public water supply reservoirs in eastern Connecticut | Mansfield Hollow Lake (MHL) and Willimantic Reservoir (WR) are two reservoir lakes located in eastern Connecticut in the northeastern United States. MHL formed behind the Mansfield Hollow Dam constructed by the U.S. Army Corps of Engineers in 1952 and is primarily fed by the Fenton, Mount Hope and Natchaug Rivers. The WR lies approximately 1-km downstream from the Mansfield Hollow Dam. Total dissolved nitrogen, phosphorus and chlorophyll a measurements indicate the water bodies could be classified as borderline mesotrophic/eutrophic. A steady-state numerical software package (Bathtub) designed to facilitate application of empirical eutrophication models to morphometrically complex reservoirs was used to determine the trophic status in MHL and WR based on different phosphorus and nitrogen loading budgets. The short hydraulic residence times and rapid flushing rates in MHL and WR are directly related to the flow rates in the streams discharging into MHL. The low flow period could significantly increase the hydraulic residence times of these two reservoirs. Therefore, the sampling design emphasized periods of low flow in late August and early September to assess the impact of nutrient inputs to MHL and WR during dry periods. The results of a low flow sampling period (August 2002) were used to calibrate and test the Bathtub model developed for these water bodies. Application of the Bathtub model to differing flow regimes, notably average flows, suggested that nitrogen or phosphorus could limit the productivity and cause eutrophication in the two lakes. Results of this study indicated that the Bathtub model could be used to predict total nitrogen and total phosphorus concentrations with reasonable accuracy, but it might not be a suitable tool for predicting organic nitrogen or algae in rapidly flushing lake systems. To further investigate and validate the assumptions made in this study, more sampling data are needed, especially during high intensity storm events to investigate possible sources of nutrient flow into the two lake system and further calibrate the Bathtub model for the MHL-WR watershed. |
| Response of Cylindrospermopsis raciborskii and Pseudanabaena limnetica to a potential biological control agent, bacterium SG-3 (Lysobacter cf. brunescens) | Kathryn Wilkinson Flaherty; H. Lynn Walker; Clay H. Britton; Carole A. Lembi | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 255 - 263 | Response of Cylindrospermopsis raciborskii and Pseudanabaena limnetica to a potential biological control agent, bacterium SG-3 (Lysobacter cf. brunescens) | A bacterium (SG-3) was reported by Walker and Higginbotham (2000) to lyse cells of filamentous planktonic species of cyanobacteria such as Anabaena, Oscillatoria and Lyngbya. We tested the efficacy of SG-3 in the laboratory to control Cylindrospermopsis raciborskii, a species with the potential to produce toxins, and Pseudanabaena limnetica, a species that causes taste and odor problems in water. Both were susceptible to SG-3 concentrations of 1.5 107 PFU/mL (PFU = plaque forming units), which was consistent with the concentrations used by Walker and Higginbotham (2000). In tests with a range of SG-3 concentrations (15 to 1.5 107 PFU/mL), cell numbers of the Lake Yale and Lake Griffin (FL) isolates of C. raciborskii in relation to untreated controls were reduced by 89-99% at SG-3 concentrations of 1.5 105 PFU/mL. The Lake Griffin isolate was somewhat more sensitive to SG-3 than the Lake Yale isolate. The calculated EC50 and EC100 for the Lake Griffin strain were 1.2 103 PFU/mL and 3.3 105 PFU/mL, respectively; the calculated EC50 and EC100 for the Lake Yale strain were 6.2 103 PFU/mL and 1.2 106 PFU/mL, respectively. The efficacy of SG-3 was also tested in lake water, which was spiked with the Lake Yale isolate of C. raciborskii; cell counts were reduced from 83 to 95% at SG-3 concentrations of 7.5 106 PFU/mL and higher. SG-3 concentrations greater than those that significantly reduced new cell growth were required to kill the initial populations of the Lake Yale strain present prior to treatment. Pretreatment cell numbers of the C. raciborskii isolates were consistent with those recorded in heavily infested lakes. Therefore, SG-3 at the higher end of the concentration range can kill bloom populations; however, it can also be applied at lower concentrations to act as an algistat on the initial cell populations while preventing additional bloom development, an approach that would avoid potential environmental damage from the cell release of toxins or taste and odor compounds. |
| Tracking long-term acidification trends in Pockwock Lake (Halifax, Nova Scotia), the water supply for a major eastern Canadian city | Amy E. Tropea; Brian K. Ginn; Brian F. Cumming; John P. Smol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 279 - 286 | Tracking long-term acidification trends in Pockwock Lake (Halifax, Nova Scotia), the water supply for a major eastern Canadian city | Pockwock Lake, the drinking water supply for the city of Halifax (Nova Scotia, Canada), has been impacted by the deposition of strongly acidic anions. Because long-term monitoring data are lacking, we used diatom-based paleolimnological techniques to track changes in water quality variables in this important water source. Similar to other acidified lakes in this region, Pockwock Lake has undergone changes in diatom assemblages starting ~1940 with a corresponding lakewater pH decrease of 1.2 units. Before ~1940, Pockwock Lake had a diatom-inferred pH ~6.3 and a diatom assemblage dominated by Cyclotella stelligera and Asterionella ralfsii var. americana (>45 μm). With the onset of acidification, diatom-inferred lakewater pH decreased to ~5.8 and there was a shift to dominance by A. ralfsii var. americana (>45 μm) and Tabellaria flocculosa. A subsequent shift in diatom assemblages and inferred lakewater pH was recorded ~1990 suggesting a decrease in dissolved organic carbon (DOC) and water colour. Since ~1992 Pockwock Lake has undergone further acidification, as evidenced by a shift in the diatom assemblage to dominance by Fragilaria acidobiontica, Eunotia spp., and Frustulia pseudomagaliesmontana. Both diatom-inferred and measured lakewater pH = 5.1 during this time interval. The first (~1940-1992) acidification period followed the trend observed in other humic (high DOC) Nova Scotia lakes, whereas the second (post ~1992) acidification event resulted in a diatom assemblage more common in acidified clearwater (low DOC) lakes. Thus, the acidification signal observed in Pockwock Lake likely indicates a change in diatom assemblage resulting from a loss of DOC, and the sudden drop in diatom-inferred pH suggests that the weak acid buffering system of humic DOC had been exceeded. Further acidification and loss of DOC in this lake has the potential to increase the availability of metals in this important water source. |
| Response of calcareous Nagawicka Lake, Wisconsin, to changes in phosphorus loading | Dale M. Robertson; Herbert S. Garn; William J. Rose | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 298 - 312 | Response of calcareous Nagawicka Lake, Wisconsin, to changes in phosphorus loading | Nagawicka Lake is a 400-ha, phosphorus (P)-limited, calcareous lake (hardness of 300 mg/L CaCO3) in Wisconsin. Because of concern over potential degradation in water quality associated with urban development in the watershed, a study was conducted to determine the effects of past and future changes in P loading on the lake's water quality through the use of empirical eutrophication models. Six existing empirical P models consistently overestimated total P (TP) concentrations in the lake by a factor of about 2 over a range in external P loading because the models do not account for the unique properties of calcareous lakes: co-precipitation of P with calcite and negligible release of P from the deep sediments. Confirmation of the calcite mechanism was proven by analysis of sediment cores. Once the results were adjusted for the consistent biases, other conventional empirical models fairly accurately predicted the measured chlorophyll a concentrations (CHL) and Secchi depths in the lake. The models, adjusted for the consistent overestimation of TP, were then used to predict the effects of increases and decreases in P loading. Total P and CHL were predicted to decrease or increase by a % similar to the % change in P loading to the lake; however, these relations may become very nonlinear with increases in P loading >100%. Because the natural buffering capacity resists eutrophication caused by P loading, roughly twice the P loading can be permitted in oligotrophic calcareous lakes than in noncalcareous lakes before eutrophication thresholds are exceeded. |
| Factors affecting the maximum depth of colonization by submersed macrophytes in Florida lakes | Alexis J. Caffrey; Mark V. Hoyer; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 3 | 2007 | 287 - 297 | Factors affecting the maximum depth of colonization by submersed macrophytes in Florida lakes | In 32 Florida lakes, Secchi depth (SD), light attenuation coefficient measured with a light meter, plant and sediment type, and slope were examined with respect to the maximum depth of plant colonization (MDC). The MDC was shown to be significantly related to light through measurements taken by SD (R2 = 0.46; p < 0.05) and a light meter (R2 = 0.41; p < 0.05). While both light measurements can be used to estimate MDC, SD accounted for more variance in MDC than light attenuation coefficients. Plant type, sediment type and slope did not account for more variance in MDC than light measurements for these Florida lakes. Additional unpublished data from 187 Florida Lakes (Florida LAKEWATCH, 279 lake-years of data) also showed a significant positive relationship between SD and MDC (R2 = 0.68; p < 0.05). The best fit MDC-SD regression line in meters was: log (MDC) = 0.66 log (SD) + 0.31. A maximum MDC line relating MDC to SD in meters was also calculated and was found to be equal to: log (max MDC) = 0.53 log (SD) + 0.59. The maximum MDC line describes light limitation when the MDC response falls on or near the response curve, and when MDC values fall below the line, some other factor likely limits colonization of macrophytes. |
| Identification of cyanobacterial toxins in Florida's freshwater systems | Christopher D. Williams; Mark T. Aubel; Andrew D. Chapman; Peter E. D'Aiuto | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 144 - 152 | Identification of cyanobacterial toxins in Florida's freshwater systems | Toxigenic cyanobacteria are common components of Florida's surface waters and may pose a threat to their ecology and a risk to human health. The Lake County Water Authority, the Florida Department of Health, the St. Johns River Water Management District, the South Florida Water Management District, and the Lee County Health Department have all recently monitored local waters for cyanotoxins. In 2004, 6 central Florida lakes were sampled monthly for 12 months at centrally located open water sample sites. Toxin data (n = 72 for all toxin analyses) showed that microcystins (0.1-3.6 μg/L) were present in all 12 months; multiple bloom events per lake were observed; bloom concentrations ranged from 5-7,500 μg/L; and blooms occurred throughout the entire year. Cylindrospermopsin, ranging in concentration from 0.05 to 0.2 μg/L, was reported in 22% of all samples analyzed and occurred predominantly between August and December. Anatoxin-a was not reported in 2003/2004 but was identified in 2002/2003 (30%, 0.05-7.0 μg/L). Data from the St. Johns River was similar to that of the central Florida lakes. In general, microcystins ranged between 0.1 and 31 μg/L and were detected in all samples (n = 50), while cylindrospermopsin was observed less frequently (30%, n = 48) and at lower concentrations (0.07-1.6 μg/L). Anatoxin-a was not reported (n = 48). In contrast, the major Microcystis spp. blooms that occurred in the St. Johns, the St. Lucie, and the Caloosahatchee rivers in 2005 were reported to contain relatively high levels of microcystins (rangemax. conc.= 278-5700 μg/L) and persisted for approximately 2 months. Data indicate that cyanotoxin production can be a year-round phenomenon in Florida and can occur at levels that may cause ecological and human health problems. |
| A preliminary exposure assessment of microcystins from consumption of drinking water in the United States | Anthony Fristachi; Glenn Rice; Jeffery Steevens; Igor Linkov | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 203 - 210 | A preliminary exposure assessment of microcystins from consumption of drinking water in the United States | This preliminary human exposure assessment of cyanotoxins from consumption of treated drinking water in the United States is based on reported concentrations of microcystin-LR equivalents, (herein referred to as MC-LR), a cyanotoxin measured in a study of North American drinking waters conducted by the American Water Works Association from June 1996 to January 1998. The sampling protocol resulted in a distribution of MC-LR concentrations in waters that likely overestimates the actual distribution encountered by the exposed population, yielding conservatively biased estimates of exposure. Over a 75-year lifetime, the estimated lifetime average daily dose of MC-LR from the consumption of drinking water was estimated to be 1.7 10-3 μg/kg-day with a standard deviation of 0.02. The 90 and 95 percentile exposure estimates were 1.5 10-3 and 3.9 10-3, respectively. Our results suggest that most individuals are exposed to cyanotoxin levels in finished North American drinking waters that are approximately an order of magnitude lower than the World Health Organization's provisional guideline level of 1 μg/L, which corresponds to approximately 0.04 μg/kg-day. |
| Preface | Jennifer L. Graham; Ann St. Amand; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | i | Preface | |
| The occurrence and response to toxic cyanobacteria in the Pacific Northwest, North America | J. M. Jacoby; J. Kann | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 123 - 143 | The occurrence and response to toxic cyanobacteria in the Pacific Northwest, North America | Toxic cyanobacteria are of increasing concern in the Pacific Northwest region of North America. Toxic blooms have been documented in Idaho, northern California, Oregon, Washington, and British Columbia and have caused animal poisonings, lake closures, and public health concerns. Microcystins are the most commonly detected cyanotoxins in this region and have been found at water concentrations from <1 μg/L to 30 mg/L. Anatoxins have also been measured in water bodies throughout the region and have been implicated in the deaths of both domestic and wild animals. Environmental factors associated with the occurrence of toxic blooms have been studied in several western Washington lakes. In these lakes, toxic blooms occurred during conditions of high phosphorus, water temperatures, and water column stability. Migration of cyanobacteria from the sediments contributed to toxic blooms in one of the lakes. Although regulations have not been formally adopted by the states and province in this region, some local jurisdictions use the World Health Organization proposed drinking water guideline of 1 μg/L microcystin-LR to close lakes to recreational use and for drinking water supplies. Recommendations currently advocated by Oregon take into account genera-specific differences, as well as separate, less stringent guidelines for recreational water bodies not used for drinking water. |
| Cyanobacterial toxins in Canadian freshwaters: A review | B. G. Kotak; R. W. Zurawell | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 109 - 122 | Cyanobacterial toxins in Canadian freshwaters: A review | Cyanobacterial toxins are a serious water quality concern in productive water bodies worldwide. Microcystins (MCs), which are hepatotoxins, are prevalent in Canadian freshwaters while the occurrence of neurotoxins anatoxin-a, anatoxin-a(s) and saxitoxin appears to be much less common. Concentrations of microcystin-LR (MCLR), presumed to be the most common of the more than 70 MC analogues, are highly variable in phytoplankton assemblages of lakes and greatly influenced by phytoplankton species composition. The frequency of occurrence and concentrations of MC in lakes in western Canada tend to increase with lake trophic status as well as decreasing N:P ratio. Microcystins accumulate in the aquatic food web through feeding activities of invertebrates (i.e., filter-feeding by clams and grazing by zooplankton and gastropods). Eventual trophic transfer of MC to fish, and resulting mortalities have been documented. Human health may also be at risk. Conventional water treatment may adequately remove low MC concentrations from source water, but can fail to completely remove MCs when initial concentrations are high. To address human health concerns, Health Canada established a drinking water guideline of 1.5 μg/L of MCLR. More recently, it has been suggested that β/N-methylamino-L-alanine (BMAA), a non-protein amino acid produced by many species of cyanobacteria, may cause neuro-degenerative disease, thus representing a significant emerging health issue. |
| Microcystin distribution in physical size class separations of natural plankton communities | Jennifer L. Graham; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 161 - 168 | Microcystin distribution in physical size class separations of natural plankton communities | Phytoplankton communities in 30 northern Missouri and Iowa lakes were physically separated into 5 size classes (>100 μm, 53-100 μm, 35-53 μm, 10-35 μm, 1-10 μm) during 15-21 August 2004 to determine the distribution of microcystin (MC) in size fractionated lake samples and assess how net collections influence estimates of MC concentration. MC was detected in whole water (total) from 83% of lakes sampled, and total MC values ranged from 0.1-7.0 μg/L (mean = 0.8 μg/L). On average, MC in the >100 μm size class comprised ~40% of total MC, while other individual size classes contributed 9-20% to total MC. MC values decreased with size class and were significantly greater in the >100 μm size class (mean = 0.5 μg/L) than the 35-53 μm (mean = 0.1 μg/L), 10-35 μm (mean = 0.0 μg/L), and 1-10 μm (mean = 0.0 μg/L) size classes (p < 0.01). MC values in nets with 100-μm, 53-μm, 35-μm, and 10-μm mesh were cumulatively summed to simulate the potential bias of measuring MC with various size plankton nets. On average, a 100-μm net underestimated total MC by 51%, compared to 37% for a 53-μm net, 28% for a 35-μm net, and 17% for a 10-μm net. While plankton nets consistently underestimated total MC, concentration of algae with net sieves allowed detection of MC at low levels (≤0.01 μg/L); 93% of lakes had detectable levels of MC in concentrated samples. Thus, small mesh plankton nets are an option for documenting MC occurrence, but whole water samples should be collected to characterize total MC concentrations. |
| The occurrence of cyanobacterial toxins in New York lakes: Lessons from the MERHAB-Lower Great Lakes program | Gregory L. Boyer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 153 - 160 | The occurrence of cyanobacterial toxins in New York lakes: Lessons from the MERHAB-Lower Great Lakes program | New York State is bordered by Lake Erie, Lake Ontario and Lake Champlain, which provide recreational opportunities and drinking water for over 20 million people. Little is known about the occurrence of toxic cyanobacteria in New York waters. In 1999 and 2000, several dogs died from anatoxin-a poisoning after contact with Lake Champlain algae. In response to these events, an intensive field program was initiated to develop and evaluate monitoring methods for detection of cyanobacterial toxins in freshwater systems. This work resulted in the development of a tier-based system for monitoring harmful algal blooms. Between 2000 and 2004, more than 2,000 samples were collected and analyzed for the occurrence of cyanobacterial toxins from sites across New York State. These samples were tested for the hepatotoxic microcystins and cylindrospermopsin as well as the neurotoxins, anatoxin-a, and paralytic shellfish poisons (PSP). A simple extraction procedure using 50% methanol gave >90% recovery of PSP toxins, microcystins, and anatoxin-a from a single sample. This extract was analyzed for cyanobacteria toxins using multiple techniques including ELISA, enzyme inhibition assays, and HPLC with fluorescence, photodiode array, or mass spectrometry detectors. Microcystins were found at >1 μg L-1 in 15% of the samples. Anatoxin-a was found less frequently but was often associated with animal fatalities. The PSP toxins and cylindrospermopsin were found only in rare instances. In some lakes (i.e., Oneida Lake), >50% of the samples tested positive for microcystins. These results suggest that cyanobacterial toxins may be a common event in eutrophic waters, and their occurrence should be a concern for lake managers and public health officials. |
| First assessment of cyanobacterial blooms and microcystin-LR in the Canadian portion of Lake of the Woods | Huirong Chen; Janice M. Burke; W. Paul Dinsmore; Ellie E. Prepas; Phillip M. Fedorak | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 169 - 178 | First assessment of cyanobacterial blooms and microcystin-LR in the Canadian portion of Lake of the Woods | Cyanobacterial blooms containing the hepatotoxin microcystin-LR (MC-LR) occurred at least once at each of 5 sites sampled in June, July and August 2004 in the Boreal Shield (Ont., Canada) portion of Lake of the Woods. In June, cyanobacteria constituted 3.5-49% (median 25%) of total phytoplankton biomass and consisted largely of Aphanothece spp. (median 98% of total cyanobacterial biomass). In July and August, cyanobacteria comprised 54-98% (median 77%) of total phytoplankton biomass in surface water samples and consisted largely of Aphanizomenon flos-aquae (median 82% of total cyanobacterial biomass). Three species of Anabaena (A. flos-aquae, A. lemmermannii, and A. mendotae), as well as Homeothrix janthina, Pseudanabaena spp., Aphanocapsa spp., and Woronichinia spp. were also present during the study period. Among study sites, total phosphorus concentrations in surface grab samples ranged from 11 to 31 μg/L and were positively associated with total cyanobacterial biomass (r = 0.64, P = 0.01). MC-LR concentrations (μg/g dry weight) in bloom material collected with a 64-μm tow net and analyzed by High Performance Liquid Chromatography were positively related to ammonium concentrations in surface grab samples (r = 0.94, P = 0.001), but not to the total biomass of cyanobacteria or any cyanobacterial taxon. In the isolated Boreal Shield basins of this lake, cyanobacterial blooms and cyanotoxins like MC-LR may have ecological and human health consequences and may be sensitive indicators of human disturbance in the drainage basin. |
| Efficacy of molecular DNA methods for confirming species identifications on morphologically variable populations of toxin-producing Anabaena (Nostocales) | Ann St. Amand; Juli Dyble; Mark Aubel; Andrew Chapman; Joseph Eilers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 193 - 202 | Efficacy of molecular DNA methods for confirming species identifications on morphologically variable populations of toxin-producing Anabaena (Nostocales) | Algal samples were analyzed from 3 lakes, Crane Prairie Reservoir and Odell Lake in Oregon and an Anonymous North East System, using both standard taxonomic criteria for identification and DNA sequencing techniques. Two toxin-producing Anabaena populations, one with consistent akinete structure and another with variable akinete structure, were investigated. Samples were characterized based on several genetic markers (nifH, cpcBA-IGS, ITS1), toxins (anatoxin-a, saxitoxin, and microcystin) and morphological variation. Taxonomy within the Nostacales is based on vegetative and terminal cell structure, filament type and aggregation, and position and structure of heterocysts and akinetes. Many taxonomists rely heavily on akinete structure for microscopic identification. Identification from material preserved with Lugol's solution is challenging due to the breakup of colonies, cell distortion, and masking of pigment color. Based on morphological variation, the Crane Prairie and Odell populations were identified as A. flos-aquae, A. circinalis, or A. lemmermannii, and toxin analysis detected the presence of microcystin. These populations were most similar to A. lemmermannii (cpcBA-IGS) or Anabaena sp. (ITS1) by DNA sequence analysis. The Anonymous North East System population was identified as A. flos-aquae, A. circinalis or A. spiroides based on morphological variation, and both microcystin and anatoxin-a were detected in these samples. Sequences most similar to A. cylindrica (nifH), A. planktonica (cpcBA-IGS), A. spiroides or Aphanizomenon flos-aquae (ITS1) were identified in the Anonymous North East System samples, but there were no definitive matches. Although molecular methods can be useful tools for confirming identification based on field material, their ability to resolve issues of taxonomic identification are dependent on the comprehensiveness of the sequence database. Taxonomic keys based on cell morphology and identification based on current DNA sequence databases are subject to similar levels of variation and uncertainty. |
| Eutrophication and cyanobacteria blooms in run-of-river impoundments in North Carolina, U.S.A. | Brant W. Touchette; JoAnn M. Burkholder; Elle H. Allen; Jessica L. Alexander; Carol A. Kinder; Cavell Brownie; Jennifer James; Clay H. Britton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 2 | 2007 | 179 - 192 | Eutrophication and cyanobacteria blooms in run-of-river impoundments in North Carolina, U.S.A. | We compared monthly data taken during the dry summer growing season of 2002 in 11 potable water supply reservoirs (19-85 years old based on year filled) within the North Carolina Piedmont, including measures of watershed land use, watershed area, reservoir morphometry (depth, surface area, volume), suspended solids (SS), nutrient concentrations (total nitrogen, TN; total Kjeldahl nitrogen, TKN; nitrate + nitrite, NO3- + NO2-; total phosphorus, TP; total organic carbon), phytoplankton chlorophyll a (chla) concentrations, cyanobacteria assemblages, and microcystin concentrations from monthly data taken during the dry summer 2002 growing season. The reservoirs were considered collectively or as two subgroups by age as “mod.†(moderate age, 19-40 years post-fill, n = 5) and “old†(74-85 yr post-fill, n = 6). The run-of-river impoundments were meso-/eutrophic and turbid (means 25-125 μg TP/L, 410-1,800 μg TN/L, 3-70 μg chla/L and 5.7-41.9 mg SS/L). Under drought conditions in these turbid systems, there was a positive relationship between chla and both TN and TP, supported by correlation analyses and hierarchical ANOVA models. The models also indicated significant positive relationships between TN and TP, and between SS and both TP and TN. Agricultural land use was positively correlated with TKN for the reservoirs considered collectively, and with TN, TKN, TP, and chla in mod. reservoirs. In models considering the reservoirs by age group, TN:TP ratios were significantly lower and NO3- + NO2- was significantly higher in old reservoirs, and these relationships were stronger when reservoir age was used as a linear predictor. Cyanobacteria assemblages in the two reservoir age groups generally were comparable in abundance and species composition, and comprised 60-95% (up to 1.9 106 cells/mL) of the total phytoplankton cell number. Potentially toxic taxa were dominated by Cylindrospermopsis raciborskii and C. philippinensis. Although known microcystin producers were low in abundance, microcystin (< 0.8 μg/L) was detected in most samples. TP and chla were significant predictors of total cyanobacterial abundance. The data suggest that at present these turbid, meso-/eutrophic reservoirs have moderate cyanobacteria abundance and low cyanotoxin (microcystin) levels over the summer growing season, even in low-precipitation seasons that favor cyanobacteria. Accelerated eutrophication from further watershed development is expected to promote increased cyanobacterial abundance and adversely affect the value of these reservoirs as potable water supplies. |
| Temporal Coherence of Water Quality Variables in a Suite of Missouri Reservoirs | Matthew F. Knowlton; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 49 - 58 | Temporal Coherence of Water Quality Variables in a Suite of Missouri Reservoirs | A six-year time series of water quality data from four eutrophic prairie reservoirs located in adjacent watersheds in northwest Missouri were analyzed for seasonal patterns and temporal coherence of temperature, dissolved oxygen, transparency, major ions, nutrients, suspended solids and chlorophyll. Water temperature was strongly seasonal as determined by the square of the average correlation of monthly means among years. No other variable was consistently seasonal in all four reservoirs, although two reservoirs exhibited strong seasonality for total and dissolved nitrogen and nitrate. Percent temporal coherence, measured as the square of the correlation between paired reservoir data sets, ranged from ≥98% for water temperature to <15% for chlorophyll. Ionic constituents (especially magnesium and alkalinity) and phosphorus fractions (dissolved, total and soluble reactive) had the strongest coherence (43-66%) averaged across all reservoir pairs. Algal biomass as chlorophyll and volatile solids had the weakest temporal coherence (0-21%). Other variables showed intermediate coherence (≥35%) for one or more reservoir pairs. Coherence strength between reservoirs was related to juxtaposition of catchments and probably reflects catchment-specific features. Temporal synchrony among these reservoirs may reflect a greater influence of external conditions on nutrients than transparency or algal biomass. |
| Phosphorus and Nitrogen Budgets: Implication of Calcite Precipitation and N:P Ratio in Regulating Chlorophyll a Values | Sabah UI Solim; Ashwani Wanganeo | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 1 - 10 | Phosphorus and Nitrogen Budgets: Implication of Calcite Precipitation and N:P Ratio in Regulating Chlorophyll a Values | Two strong mechanisms, calcite precipitation and chronic low N:P ratio level, are determined to operate in Dal Lake (a shallow Himalayan lake) during the growth period from April to August, and jeopardize the influence of TP and TN loading of 5.89 g/m2 yr-1 and 35.73 g/m2 yr-1, respectively, by restricting the average column chlorophyll a values to 14.1 mg m-3. Biogenic calcite precipitation was brought about during photosynthesis by dense macrophytic populations (average fresh biomass of 3.28 kg/m2) and was aided by increasing temperatures, pH, Saturation index (SI) and flushing rate. During the spring-summer period, from April to August, the average export NP ratio of 9:1 was reduced to 2.1:1 in the ambient system. The nitrogen dependence of algal biomass development was determined for the first time for this lake system by observing a better linear plot between TN loading yr-1 vs. chlorophyll a values (r2 = 0.37, r = 0.61, p = 0.06) instead of TP loading yr-1 vs. chlorophyll a values (r2 = 0.16, r = 0.40, p >0.05). This was further confirmed through two in situ experiments, where chlorophyll a was observed to increase progressively with increasing nitrogen share in NP ratio. Significant linear correlated plots were observed between enrichment medium having NP ratio of 4:1 to 16:1 at an interval of 4 vs. chlorophyll a (r = 0.95, r2 = 0.91 at p<0.05) and enrichment medium having NP ratio of 4:1 to 18:1 at an interval of 2 vs. chlorophyll a (r = 0.73, r2 = 0.53 at p<0.5). |
| Persistence and Remobilization of Arsenic in Massachusetts (USA) Lakes Treated With Arsenical Herbicides | Paul R. Lattanzi; David B. Senn; Jenny A. Jay; Valerie Monastra; Kathleen M. Regan; John L. Durant | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 59 - 68 | Persistence and Remobilization of Arsenic in Massachusetts (USA) Lakes Treated With Arsenical Herbicides | From 1953 to 1969 the Commonwealth of Massachusetts funded a program to evaluate the effectiveness of sodium arsenite for treating algae and macrophytes in lakes. It is well known that arsenic (As) is persistent in the environment; however, little work has been done to determine its long-term fate in the treated lakes. Once sodium arsenite is added to lakes, As typically precipitates and accumulates in bottom sediments, but under certain conditions As in surface sediments can be remobilized to the water column under certain conditions. The goals of this study were to determine whether residual As is present in elevated concentrations in the surface sediments (top 0-15 cm) of treated lakes, and whether As is being significantly remobilized. Eleven lakes were studied: five were known to have been treated with sodium arsenite; three were suspected of having been treated; and three untreated lakes were used for reference. Surface sediment grab samples were collected at multiple locations in each lake and analyzed for total As. In addition, water samples were collected along a vertical transect at the deepest point in each lake and analyzed for total As. In three of the five treated lakes and one of the lakes suspected of having been treated, sediment As concentrations were >100 mg/kg, or about four-fold higher than background. Analysis of the water samples showed that As was being remobilized from sediments of both the treated and untreated lakes where reducing conditions existed. The highest concentrations of dissolved As were measured in the bottom waters of treated lakes at levels >100 μg/L, which is about 50-fold higher than background. Elevated As levels in the sediments of treated lakes could have implications for lake management. |
| Long-term Increases in Oxygen Depletion in the Bottom Waters of Boulder Basin, Lake Mead, Nevada-Arizona, USA | James F. LaBounty; Noel M. Burns | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 69 - 82 | Long-term Increases in Oxygen Depletion in the Bottom Waters of Boulder Basin, Lake Mead, Nevada-Arizona, USA | Long-term changes in the hypolimnetic volumetric oxygen demand (HVOD) of Boulder Basin, Lake Mead were determined from dissolved oxygen profiles collected from 1991 to 2007. HVOD is the rate at which oxygen in a deep layer in contact with the sediments is depleted during the period of thermal and/or chemical stratification. Generally, the rate at which oxygen is depleted is correlated to the amount of organic debris in the hypolimnion and sediments. The sediment oxygen demand reflects historical organic loading, while HVOD is a measure of productivity because of the organic particles settling from above. The lower hypolimnion in Boulder Basin remains relatively stable during the stratification period, enabling the calculation of HVOD in the near-bottom water layer. Small increases and/or decreases that occur in temperature and dissolved oxygen concentrations are detectable. Boulder Basin fully destratifies every other year on average, but mixes only partially in the spring (before May) of the remaining years. The HVOD rates after partial and complete destratification have been assessed separately for 1995-2005. The annual HVOD rate is generally lower the year after partial destratification than after complete destratification due to greater downward transport of oxygen into the hypolimnion. The HVOD of Boulder Basin is variable depending on loading of nutrients and water into the Basin. The rate dropped significantly following commencement of advanced wastewater treatment practices in 1994. The rates then increased 1996-2006 at a rate of approximately 0.75 mg DO/m3/day per year, or about 7% annually. During those years the inputs of nutrients steadily increased. Rates have been dropping from 2005 to present (2007) following further reduction of phosphorus input. A multiple regression analysis revealed that HVOD is significantly positive related to the total phosphorus concentration in Las Vegas Bay, but significantly negative to inflows of Colorado River water. That means HVOD was highest when reservoir water was nutrient-rich and flow rates were low. HVOD should be considered a major tool for monitoring trophic state changes in Boulder Basin. |
| Comparison of an Urban Lake Targeted for Rehabilitation and a Reference Lake Based on Robotic Monitoring | Joseph S. Denkenberger; Charles T. Driscoll; Steven W. Effler; David M. O'Donnell; David A. Matthews | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 11 - 26 | Comparison of an Urban Lake Targeted for Rehabilitation and a Reference Lake Based on Robotic Monitoring | A reference lake, Otisco Lake, NY, was selected to evaluate rehabilitation initiatives to mitigate severe cultural eutrophication of Onondaga Lake, NY. Onondaga Lake was mesotrophic before European development. The reference lake selection was based on an analysis of paired monitoring datasets for temperature, fluorometric chlorophyll (Chlf/a) and dissolved oxygen (DO), collected daily by robotic profiling platforms for the spring to fall interval of three years. The various metrics of trophic state documented here for Otisco Lake represent reasonable informal interim goals for the rehabilitation of the cultural eutrophication of Onondaga Lake. The use of Otisco Lake as a reference site is supported by its similar stratification/mixing regime and mesotrophic state, in addition to its proximity (~25 km) and similar morphometry with Onondaga Lake. Strong contrasts in water quality manifestations of trophic state are depicted in Onondaga Lake, including higher Chlf/a (3.5-fold), prevalence of blooms, greater deviations of DO from saturation conditions, much lower minimum DO values at fall turnover in the upper layers and a higher volumetric hypolimnetic oxygen deficit (VHOD; 1.55-fold). Advantages of the fine vertical and temporal scale capabilities of the monitoring platforms are demonstrated in characterizing these and other limnological features. Continued robotic monitoring at Otisco Lake as a reference site and Onondaga Lake through the rehabilitation program will support ongoing comparisons to assess progress and will help engage stakeholders in the process. |
| Inferred Phosphorus Cycling in Shallow and Deep Basins of Eutrophied Lake Hormajärvi, Southern Finland | Samu Valpola; Jutta Forsell; Veli-Pekka Salonen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 95 - 107 | Inferred Phosphorus Cycling in Shallow and Deep Basins of Eutrophied Lake Hormajrvi, Southern Finland | Lake Hormajrvi is a typical small lake in southern Finland suffering from human-induced eutrophication. The lake has a complex basin morphology; the western basin is deeper and does not suffer the consequences of eutrophication of the shallower eastern basin, where poor water quality prevents swimming, fishing and other recreational use of the lake. Two short sediment cores from both basins were taken and studied to understand the eutrophication history of the lake, phosphorus (P) cycling within the respective basins and to evaluate needs for lake management and restoration. Sediments were analyzed for diatoms, P fractions, and physical properties. Spherical carbonaceous particles (SCP) were used for dating. Results indicate that diatom inferred autumnal lake surface water total P (DITP) does not follow the trend in accumulated P in the western basin, whereas there is a clear correlation in the eastern basin. The western basin acts as a permanent sink for P, but in the unstratified eastern basin, P released from sediment circulated throughout the water column. Results demonstrate that lake management or restoration decisions should not be made based on water quality and algal bloom observations alone. Detailed paleolimnological studies provide essential information to understand processes in complicated basins like Lake Hormajrvi. |
| Whole-lake Herbicide Treatments for Eurasian Watermilfoil in Four Wisconsin Lakes: Effects on Vegetation and Water Clarity | Kelly I. Wagner; J. Hauxwell; P. W. Rasmussen; F. Koshere; P. Toshner; K. Aron; D. R. Helsel; S. Toshner; S. Provost; M. Gansberg; J. Masterson; S. Warwick | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 83 - 94 | Whole-lake Herbicide Treatments for Eurasian Watermilfoil in Four Wisconsin Lakes: Effects on Vegetation and Water Clarity | Four pilot whole-lake herbicide treatments for extensive Eurasian watermilfoil (EWM) (Myriophyllum spicatum L.) infestations were conducted in Wisconsin between 1997 and 2001 using fluridone at a range of dosages (6-16 μg/L). Annual post-treatment data (4-7 years) were evaluated to assess (1) effects on exotic plants; (2) changes to native plant communities; and (3) effects on water clarity. Temporal shifts in treatment lakes were compared against natural fluctuations in untreated reference lakes. In conjunction with aggressive follow-up spot treatments with 2,4-D or manual removal, fluridone treatments provided between 1 and 4 years of substantial EWM relief, with the exotic ultimately re-establishing at pre-treatment levels or greater in 3 of the 4 lakes. Native plant communities shifted in all 4 lakes following fluridone treatment. The large decreases, outside the range seen in untreated lakes (first quartile of the reference lake distribution) for all treatment lakes containing EWM, Elodea canadensis, Ceratophyllum demersum, and Najas flexilis, strongly suggest a direct effect of the fluridone treatment. We observed large increases, outside the range seen in untreated lakes (fourth quartile of the reference distribution), for 1 of 2 treatment lakes with Potamogeton crispus, and 1 of 2 treatments with Chara spp. Secchi depth decreased significantly in 2 of the 3 lakes for which data were available. Future applications should consider, among other criteria, the dominant natives in the plant community, their sensitivity to fluridone, and potential impacts associated with decreased water clarity. |
| Potential Effects of Sediment Dredging on Internal Phosphorus Loading in a Shallow, Subtropical Lake | K. R. Reddy; M. M. Fisher; Y. Wang; J. R. White; R. Thomas James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 27 - 38 | Potential Effects of Sediment Dredging on Internal Phosphorus Loading in a Shallow, Subtropical Lake | Long-term phosphorus (P) loading to lakes has resulted in accumulation of P in sediments. Internal nutrient loading from sediments of shallow lakes such as Lake Okeechobee, Florida, has become a major concern in restoration programs. The objectives of this study were to determine (1) the potential impact of dredging on dissolved reactive P (DRP) flux out of sediments and (2) the equilibrium P concentration (EPCw) of post-dredge sediments. Intact sediment cores from one location representing P-laden mud sediments of the lake were obtained. Four simulated dredging treatments were implemented: control (no dredging-current conditions); top 30 cm; 45 cm; and 55 cm sediment removal. Phosphorus release/retention characteristics of sediments were determined at water-column DRP concentrations of 0, 0.016, 0.032, 0.064, and 0.128 mg/L. The water column in each core was replaced at approximately 60-day intervals, for a period of 1.2 years, with fresh lake water spiked with respective P concentrations. Significant decreases in water column DRP were observed only in sediment cores with 0-30 cm dredging. At ambient water column DRP levels, the P fluxes during the first 32 days were 0.4, 0.1, 0.4 and 0.2 mg P/m2/day for the 0, 30, 45, and 55 cm dredging treatments, respectively, and accounted for 11-38% of total P released during the 431 day study. At the end of the 1.2-year study, estimated EPCw were on the order of 0.033, 0.008, 0.022, and 0.037 mg P/L for 0, 30, 45 and 55 cm dredging treatments, respectively. Dredging the top 55 cm sediments would result in the removal of approximately 123 g P/m2, as compared to 80 and 108 g P/m2 for 30 and 45 cm dredging, respectively. Laboratory experiments suggest that dredging can reduce internal P loading. However, further evaluation is needed to determine the extent to which the controlled laboratory experiments can be used to predict fluxes in the lake under natural conditions, and the long-term sustainability of improving water quality by dredging. |
| Differential Prey Selectivity of Largemouth Bass Functional Feeding Groups in Twin Lakes, Washington | David R. Christensen; Barry C. Moore | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 23 | 1 | 2007 | 39 - 48 | Differential Prey Selectivity of Largemouth Bass Functional Feeding Groups in Twin Lakes, Washington | Largemouth bass (Micropterus salmoides) can be top-down regulators in a fish community. It is important for fisheries biologists who manage predator-prey populations to understand when bass become piscivorous. We examined the stomach contents of 622 largemouth bass in watershield (Brasenia schreberi) beds in North and South Twin Lakes, Washington. Bass displayed temporal and ontogenetic diet variation within and between lakes. Bass <100 mm fed principally on zooplankton and scuds in June and September and on benthic invertebrates, especially midge and damselfly larvae, during July and August. Damselflies, midges and scuds were major diet constituents for bass 100-199 mm. Bass 200-299 mm consumed large numbers of macroinvertebrates but also fed on crawfish and golden shiner (Notemigonus crysoleucus). Overall, the importance of large prey items like golden shiners and crawfish increased while macroinvertebrate importance to bass diets decreased as the fish grew larger. Bass piscivory was focused on golden shiners and was only observed in larger fish >300 mm. Golden shiner consumption was the lowest during June and September when cannibalism, crawfish and trout consumption increased. Temporal and ontogenetic variability in bass diets is most likely due to habitat variability, fish size, and prey availability and size. Manipulation of bass piscivory through slot-length-limits and/or macrophyte removal could be examined as a potential method for controlling nuisance forage fish such as golden shiners. |
| Posteruption Response of Phytoplankton and Zooplankton Communities in Spirit Lake, Mount St. Helens, Washington | Douglas W. Larson; Jim Sweet; Richard R. Petersen; Charles M. Crisafulli | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 4 | 2006 | 273 - 292 | Posteruption Response of Phytoplankton and Zooplankton Communities in Spirit Lake, Mount St. Helens, Washington | Spirit Lake, Washington was radically altered limnologically by the May 1980 eruption of Mount St. Helens. The eruption provided a rare opportunity to study lake response and recovery in the wake of volcanic disturbance. During the eruption, and for several months thereafter, phytoplankton and zooplankton populations were subjected to extremely deleterious conditions. Consequently, these populations were virtually eliminated except for remnant organisms that somehow survived. During the next two years, the phytoplankton community and presumably the zooplankton community were comprised of only a few opportunistic species whose combined abundance was low. By 1983, however, phytoplankton abundance and species diversity had greatly increased due to increased lake-water transparency and increased availability of inorganic nitrogen. The reestablishment of the zooplankton community was also well underway by 1983, as indicated by the abundance of some species and the presence of most taxa that existed prior to the May 1980 eruption. By 1986, the phytoplankton and zooplankton communities were beginning to resemble those found in subalpine, oligotrophic/mesotrophic lakes in the Washington-Oregon Cascades. The rapid recovery of Spirit Lake demonstrated the vigor and resiliency of lake ecosystems and particularly plankton communities. |
| Limnological Characterization and Flow Patterns of a Three-coupled Reservoir System and Their Influence on Dreissena polymorpha Populations and Settlement During the Stratification Period | Enrique Navarro; Montse Bacardit; Luciano Caputo; Toni Palau; Joan Armengol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 4 | 2006 | 293 - 302 | Limnological Characterization and Flow Patterns of a Three-coupled Reservoir System and Their Influence on Dreissena polymorpha Populations and Settlement During the Stratification Period | During summer 2001, zebra mussels (Dreissena polymorpha Pallas) were found (500 adults m-2) in the coupled reservoir system composed by Mequinenza, Riba-Roja and Flix (Ebro River, Northeast Spain). Two years later, mussels achieved densities of 4000 adults m-2, representing the first record of successful colonization by zebra mussels in the Iberian Peninsula. An August 2003 study investigated the environmental conditions that support the successful settlement of the zebra mussel populations during the stratification period. Flow patterns in the whole system and mussel populations near the dam were characterized. Chemical characteristics of water inputs, not the usual thermal stratification, determine the deep circulation of the Ebro River along the Riba-Roja reservoir, whereas water input from one tributary into Riba-Roja flows along the top of the water. Physico-chemical stratification of the water column seems to control the observed vertical distribution of zebra mussel biomass. Larger biomass and mean body size were found in the epilimnion, while meta- and hypolimnetic individuals were smaller in size and composed a lower biomass. Moreover, to know the influence of the water drawn off for electricity production in the settlement of mussel larvae, an artificial substratum (a rope) was placed in the influence area of the dam. Results indicate that flow conditions prevailing in the drawn-water layer may increase the attachment success of mussel larvae. Results show that during the stratification period the epilimnion of Riba-Roja was functioning as a 'biological reactor' where Dreissena populations thrived. |
| Watershed Development and Sediment Accumulation in a Small Urban Lake | David J. Newman Jr.; David R. Perault; Thomas D. Shahady | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 4 | 2006 | 303 - 307 | Watershed Development and Sediment Accumulation in a Small Urban Lake | The ever-increasing development of watersheds has raised the importance of assessing and mitigating the environmental impacts on water bodies located within disturbed areas. The removal of natural landcover can increase soil erosion and runoff along creeks and rivers, leading to heavier sediment build-up in ponds and lakes and to reductions in water quality and impoundment capabilities. For this paper, we described the possible impact from urbanization on sedimentation within a small lake. Landcover maps from two different time periods were compared against lake depths to assess relationships between development and sediment buildup. By understanding the mechanisms potentially leading to the ultimate loss of this lake, it is hoped that remediation strategies to reduce future degradation may be developed. |
| Effects of Small Ponds on Stream Water Chemistry | G. Winfield Fairchild; David J. Velinsky | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 4 | 2006 | 321 - 330 | Effects of Small Ponds on Stream Water Chemistry | In many regions, small constructed ponds greatly exceed natural lakes in number and aggregate area. Many of these ponds are impoundments of small streams. Their effect in modifying stream water chemistry, however, remains poorly understood. Here we compare 19 physicochemical variables upstream vs. downstream of 11 ponds, sampled in March, May and July. The ponds greatly reduced inflow concentrations of SiO2 (by 71%), NO3- (by 82%) and PO43- (by 46%), while exporting water of higher pH, alkalinity and dissolved oxygen content, and much higher quantities of particulate and dissolved organic C, N and P than were present upstream. Higher % removals of NO3- and SiO2 were observed in ponds with longer hydraulic residence times. Based on ambient N:P ratios, algal periphyton below the ponds were likely P limited, but differential transformations of the components of total N vs. total P within the ponds greatly reduced N:P ratios downstream. |
| Application and Tests of the Canadian Water Quality Index for Assessing Changes in Water Quality in Lakes and Rivers of Central North America | John-Mark Davies | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 4 | 2006 | 308 - 320 | Application and Tests of the Canadian Water Quality Index for Assessing Changes in Water Quality in Lakes and Rivers of Central North America | The Canadian Water Quality Index (CWQI) is a tool for communicating information to the general public and governments about water quality and assessing changes in water quality over time. It has been adopted for national and provincial reporting on water quality within Canada. It is used in this study to describe changes in water quality along a prairie river system and to assess changes in river water quality prior to and after the installation of tertiary clarifiers for the removal of phosphorus from wastewater effluent. CWQI values reflected the composite assessment of changes in individual parameter concentrations along the river. There was a slight increase in the CWQI after the installation of tertiary clarifiers, which reflected the improvement of only a few components of the wastewater. Several weaknesses of the CWQI were explored, including susceptibility to sample number per index period. A sound sampling design should form the basis of any monitoring program and, to a large extent, CWQI values are a reflection of the sampling program. |
| Book Review | Kenneth J. Wagner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 4 | 2006 | 342 - 343 | Book Review | |
| Detection of Spatial and Temporal Trends in Wisconsin Lake Water Clarity Using Landsat-derived Estimates of Secchi Depth | Scott D. Peckham; Thomas M. Lillesand | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 4 | 2006 | 331 - 341 | Detection of Spatial and Temporal Trends in Wisconsin Lake Water Clarity Using Landsat-derived Estimates of Secchi Depth | The existence of large-scale spatial and temporal trends in Wisconsin's lake water clarity is a topic that has not been thoroughly investigated. This study is an effort to reliably detect these trends by utilizing three inventories of satellite-derived lake water clarity predictions for over 2,000 lakes statewide. The data were analyzed statistically on a statewide, regional, lake type, and lake area basis. Statistically significant trends in clarity were found for the state overall, as well as for particular U.S. Environmental Protection Agency Ecoregions, Wisconsin Department of Natural Resources hydrologic lake types, and lake area categories. Results will aid in the establishment of a statewide lake water clarity database and demonstrate the effectiveness of satellite-based assessments in detecting trends in water transparency over the past three decades and into the future. Documenting such trends is essential to targeting and evaluating lake management practices as well as raising public awareness of lake clarity conditions throughout the state. |
| Temporal Variation and Assessment of Trophic State Indicators in Missouri Reservoirs: Implication for Lake Monitoring and Management | Matthew F. Knowlton; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 261 - 271 | Temporal Variation and Assessment of Trophic State Indicators in Missouri Reservoirs: Implication for Lake Monitoring and Management | The magnitude and management implications of temporal variability in trophic state metrics was simulated by measuring mean values of total phosphorus (TP), total nitrogen (TN), chlorophyll (Chl) and Secchi depth (SD) in summer (May-August) and detecting trends in these variables in a virtual lake undergoing gradual (doubling over 20 years) and abrupt (doubling over two years) change. Numbers of samples required (samples per summer over number of summers) to adequately detect these rates of change were used to show the size and management implications of temporal variability. Long-term data from 116 Missouri reservoirs, including eight summer data sets based on daily sampling, provided estimates of autocorrelation and variation within and among summers (seasonal and year-to-year variance) used in Monte Carlo simulations to evaluate sampling requirements. In simulations based on median variance, obtaining long-term means with 95% confidence intervals spanning less than a factor of two took from three years (TN) to eight years (Chl) with monthly samples (n=3 per summer). For a lake with mean values doubling every 20 years, linear regression had >75% chance of detecting the trend after 13 years of monthly samples for TN, but Chl required >20 years. For a lake with Chl doubling over two years, at least six years of pre-change data and 11 years of post-change data were required before monthly sampling gave >75% probability of detecting the trend. Increasing sampling to weekly frequency (n=16 per summer) in most scenarios reduced required duration of sampling by <2 years. Variability data from lakes in other regions fall in the range exhibited by Missouri reservoirs. Results emphasize the need for long-term data to fulfill lake management needs and suggest that ordinary lake monitoring typically will not detect trends in individual lakes. |
| Influence of Chlorophyll and Colored Dissolved Organic Matter (CDOM) on Lake Reflectance Spectra: Implications for Measuring Lake Properties by Remote Sensing | Kevin D. Menken; Patrick L. Brezonik; Marvin E. Bauer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 179 - 190 | Influence of Chlorophyll and Colored Dissolved Organic Matter (CDOM) on Lake Reflectance Spectra: Implications for Measuring Lake Properties by Remote Sensing | Light reflected from lake surfaces can convey much information about water quality, especially algal abundance, humic content, turbidity and suspended solids. Light reflectance from lakes is complicated, and detailed spectra are needed for analysis of controlling factors. We obtained detailed reflectance spectra from the water surfaces of 15 lakes in east-central Minnesota and found patterns related to chlorophyll a (chl a), turbidity and humic matter (colored dissolved organic matter, CDOM). Increasing chl a and turbidity generally resulted in higher reflectance across the visible and near-infrared spectrum. Increasing CDOM led to low reflectance, especially below ~500 nm. Spectra of lakes with high chl a were distinguishable from those of lakes low in chl a, and lakes with low or high CDOM had readily distinguishable spectra. Several optical characteristics of lake water can be estimated from reflectance intensities measured over narrow wavelength bands. The ratio of reflectance at 700 nm to that at 670 nm was the best predictor of chl a over a wide range of conditions, including high turbidity and CDOM. Several relationships involving reflectance at 412, 443, 488, and 551 nm, the wavelengths used to calculate oceanic chl a from MODIS satellite data, also yielded a high R2. The ratio of reflectance at 670 nm to 571 nm provided the best estimates of humic color despite the low absorbance of CDOM at these wavelengths. Relationships involving reflectance for all 15 lakes in the range 400-500 nm, where CDOM absorbs light, had low r2 values; none was high enough for reliable estimates of lake color. For 10 lakes with low to medium chl a levels (≤10 mg m-3), regressions involving 412 and 443 nm yielded moderately good relationships. Airborne and satellite remote sensing thus might be used to identify lakes high in CDOM, and may provide reasonable estimates of humic color in lakes with low chl a levels. |
| Preliminary Results of Light Transmission under Residential Piers in Lake Washington, King County, Washington: A Comparison between Prisms and Grating | Perry F. Gayaldo; Kitty Nelson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 245 - 249 | Preliminary Results of Light Transmission under Residential Piers in Lake Washington, King County, Washington: A Comparison between Prisms and Grating | During the summers of 2003 and 2004, 11 piers (two public and nine private) were evaluated for their ability to transmit light through the decking to the water surface below. Solid decking produces distinct shading that migrating juvenile Chinook salmon appear to avoid by swimming into deeper water where more potential predators live. Two new types of surface treatments (acrylic prisms and grating) were evaluated and compared to traditionally spaced decking as well as solid decking. Grating (with 37-58% open space) was found to transmit significantly more light to the water surface below (mean = 7.5% of full sunlight) than 23 5 cm acrylic prisms (mean = 0.7% of full sunlight). In other words, compared to full sunlight, grating transmits 10 times more light under the pier than acrylic prisms. In addition, light that passes through open grating penetrates the water evenly under the pier. Light transmitted through prisms concentrates beams of light that do not always reach the water surface. |
| Estimation of Sediment Volume in Karaj Dam Reservoir (Iran) by Hydrometry Method and a Comparison with Hydrography Method | Mohammad Heidarnejad; Said Hassan Golmaee; Abolfazl Mosaedi; Mirkhalegh Z. Ahmadi | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 233 - 239 | Estimation of Sediment Volume in Karaj Dam Reservoir (Iran) by Hydrometry Method and a Comparison with Hydrography Method | Estimation of sediment volume in the reservoirs is an important management criterion in water use. Many methods are used for this purpose, including hydrography, remote sensing, hydrometry and mathematical and computer models. The high cost of field methods such as hydrography required other methods to be investigated more seriously. In the present research, the hydrometry method was used to estimate the sediment volume in Karaj Dam Reservoir, located on the southern slope of Mount Alborz of Iran. The estimation is based on evaluation of both suspended and bed-load sediments. Although the sediment rating curve method is not common in general, using corrected models based on effective factors of sediment transfer, such as time of measurement, have increased the model efficiency. For this purpose, the daily and annual suspended loads were estimated in two hydrometric stations of Seera and Beylaghan (inlet and outlet hydrometric stations of Karaj Dam) using daily water flow rates and monthly sediment rating equations. Because the empirical methods of bed load sediment did not give acceptable results, the Karaushev curve (which has suitable compatibility with Iranian rivers) was used and the ratio of bed load to suspended load was obtained based on the river slope at hydrometric stations. By using total sediment load and average sediment density, the volumes of sediment were calculated for dam inlet and outlet hydrometric stations. Subtraction of the two volumes gave the stored annual sediment in reservoir of about 406,000 m3. The sediment volume resulting from the hydrography method (from dam primary and secondary area-volume curves) was 416,000 m3, which gave 97% collation, and the trapping efficiency of the Karaj Dam was calculated to be 80%. |
| Development and Application of Rapid Antibiotic Resistance Analysis for Microbial Source Tracking in the Black River Watershed, Michigan | Lisa VanOmmeren; Elizabeth W. Alm | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 240 - 244 | Development and Application of Rapid Antibiotic Resistance Analysis for Microbial Source Tracking in the Black River Watershed, Michigan | Microbial source tracking (MST) is often a desirable component of water quality monitoring. To enable local health departments to utilize MST regularly, rapid methods need to be developed that can be performed without costly equipment, increased laboratory space, or advanced technical requirements. This paper describes the development, validation, and application of a rapid, small-scale MST method based on antibiotic resistance analysis. An automated plate reader allows for earlier and repeated measurements and can distinguish treatment effects after only six hours of incubation, compared with the overnight incubation for the conventional assay. Using this rapid MST assay, a known-source Escherichia coli (E. coli) antibiotic resistance pattern database was constructed for the Black River watershed in southeastern Michigan. The average rate of correct classification for the known-source database was 70.4% when comparing each of seven specific animal sources, 72.5% when comparing three generic animal groups (human, waterfowl, and livestock), and 88.9% when comparing human to non-human animal sources. The rapid assay and database were then used to identify the sources of E. coli at a public recreational beach as human (34%), goose (34%), and cattle (20%). |
| Use of Robotic Monitoring to Assess Turbidity Patterns in Onondaga Lake, NY | Steven W. Effler; David M. O'Donnell; Feng Peng; Anthony R. Prestigiacomo; MaryGail Perkins; Charles T. Driscoll | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 199 - 212 | Use of Robotic Monitoring to Assess Turbidity Patterns in Onondaga Lake, NY | Selected temporal and vertical patterns of turbidity (Tn) are documented for an eutrophic urban lake, Onondaga Lake, NY, and their diagnostic value in identifying hydrodynamic and metabolic processes and in estimating clarity is established. The analysis is supported by five years (spring to fall) of daily robotic profiling of Tn, temperature (T), and dissolved oxygen, and an array of more temporally limited measurements that included Tn and T levels in the major tributary input of terrigenous solids; lake particle characterizations with a profiling particle counter and a scanning electron microscope coupled with automated image analysis and X-ray microanalysis; and Secchi disc transparency (SD). Major runoff events are demonstrated to cause conspicuous short-term increases in Tn that are manifested as metalimnetic peaks in summer and early fall, associated with the entry of the negatively buoyant primary tributary source as an interflow. The annual occurrence of Tn maxima within the oxycline of the metalimnion in October is documented. Evidence supports the position that this layer is a bacterial plate of oxidizing bacteria that develops seasonally in response to increasing vertical transport of reduced species from the hypolimnion with the approach to fall turnover. A strong relationship between SD and Tn in the upper waters is reported, that is demonstrated to have utility in resolving the dynamics of substantial changes in SD that occur in the lake during clear water phases. |
| Application of a 2-Dimensional Water Quality Model (CE-QUAL-W2) to the Turbidity Interflow in a Deep Reservoir (Lake Soyang, Korea) | Yoonhee Kim; Bomchul Kim | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 213 - 222 | Application of a 2-Dimensional Water Quality Model (CE-QUAL-W2) to the Turbidity Interflow in a Deep Reservoir (Lake Soyang, Korea) | The temporal and spatial distribution of water temperature was surveyed and simulated in a deep warm monomictic reservoir (Lake Soyang, Korea). The great depth (maximum depth 118 m) and wind-sheltered dendritic shape caused stable thermal stratification in summer. Turbid storm runoff during the summer monsoon formed a 20-40 m intermediate layer distinct from the clearer epilimnion and hypolimnion. The temperature distribution and movements of the density current were simulated by using the 2-dimensional hydrologic model, CE-QUAL-W2. The model was calibrated with data from 1996 and verified with data from 1995-2002 by applying the same set of parameters and constants as used in calibration. The model could simulate temperature profiles with excellent agreement. Movement of the intermediate density current also was well simulated. The CE-QUAL-W2 model was useful in the prediction of temperature distribution and movement of density current in reservoirs, which implies merit for further employment of this model in water quality simulations. |
| Effects of Hypolimnetic Releases on Two Impoundments and Their Receiving Streams in Southwest Wisconsin | David W. Marshall; Matt Otto; John C. Panuska; Steven R. Jaeger; Donna Sefton; Thomas R. Baumberger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 223 - 232 | Effects of Hypolimnetic Releases on Two Impoundments and Their Receiving Streams in Southwest Wisconsin | The effects of bottom water withdrawals were evaluated within and below two southwestern Wisconsin impoundments. Like many man-made lakes in the unglaciated area of Wisconsin, Twin Valley Lake and White Mound Lake were constructed during the late 1960s for flood control and recreation. Both impoundments, which are located in large agricultural watersheds, were originally designed to release cold bottom water with the intended goal of managing trout below the dams. However, recent water quality monitoring results revealed that the streams became degraded due to frequent dissolved oxygen criterion violations and excessive filamentous bacteria growths. Organic loading from the bottom discharges is the likely reason that trout stream habitat was not successfully created below the dams as originally intended. Despite the accelerated phosphorus removal from the long-term withdrawals, blue-green algal blooms continued to be a problem in both impoundments. While maximizing total phosphorus export can improve lake water quality conditions, discharge rates from these impoundments were found to be excessively high, resulting in disturbance of their thermo-structure and entrainment of nutrients into the surface waters. In 2005, we blocked the bottom gate at Twin Valley Lake and monitored water quality and thermal responses. As a result, lake and stream water quality improved significantly while the downstream fish community structure did not change. The impoundment thermo-structure was restored with well-defined hypolimnion and epilimnion. We conclude that managing impoundments is often a balancing act between seemingly disparate goals of achieving optimum conditions above or below a dam, with undesirable consequences often occurring if the focus is disproportionately on a single goal. |
| Water Quantity and Quality of Mansar Lake Located in the Himalayan Foothills, India | Vijay Kumar; S. P. Rai; Omkar Singh | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 191 - 198 | Water Quantity and Quality of Mansar Lake Located in the Himalayan Foothills, India | Bathymetric survey and physico-chemical analysis of Mansar Lake, located in the Himalayan foothills in the state of Jammu and Kashmir, India, were carried out to assess water quantity and quality. The bathymetric survey indicated that Mansar Lake, with a surface area of 0.59 106 m2 at present outflow level, has a maximum depth, length and width of 38.25 m, 1204 m and 645 m, respectively. The lake mean width is 490 m, mean depth is 21 m, and mean slope of the lake floor is 0.14 m·m-1. The storage capacity of the lake up to present outflow level is 11.57 106 m3. Vertical variation of temperature, pH, electrical conductivity, dissolved oxygen, hardness and alkalinity suggest that Mansar Lake undergoes complete mixing during January and February and is stratified in other months. Calcium, magnesium and sodium are the dominant cations, and bicarbonate the dominant anion. Analysis of chemical parameters shows that the lake water is of Ca-Mg-HCO3-CO3 type. Phosphate concentration >0.03 mg·L-1 in the Mansar Lake water indicated that the lake is eutrophic. Suitable measures have been suggested for sustainable management of Mansar Lake. |
| Seasonal Dynamics of Phytoplankton Assemblages across Nutrient Gradients in Shallow Hypertrophic Lake Manyas, Turkey | Kemal Çelik; Tuğba Ongun | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 3 | 2006 | 250 - 260 | Seasonal Dynamics of Phytoplankton Assemblages across Nutrient Gradients in Shallow Hypertrophic Lake Manyas, Turkey | Species composition, abundance and size distribution (the average measure of the longest cell dimension and surface area to volume ratio) of phytoplankton in the shallow hypertrophic Lake Manyas, Turkey were studied between January 2003 and December 2004. A total of 165 species were recorded during the study. Diatoms and Cyanobacteria were the dominant taxa at most stations. Nitrate and phosphate values showed a decreasing gradient with the distance from Sigirci Inlet to Karadere Outlet. Bacillariophyta dominated the phytoplankton in spring, while Cyanobacteria prevailed in summer. Each summer, a peak of Euglenophyta was also observed at Sigirci Inlet. Nutrient gradients seemed to have a greater control over overall density than of species composition. The size distribution of the Cyanobacteria showed positive correlations with nutrient levels, while green algae and diatoms did not. There was a negative correlation between the average cell dimension of the phytoplankton cells and the surface area to volume ratio in general. The objective of this study was to determine the seasonal dynamics of species composition, abundance and size distribution of phytoplankton assemblages across nutrient gradients along a distance in the shallow hypertrophic Lake Manyas, Turkey. |
| Three-dimensional Management Model for Lake Washington, Part I: Introduction and Hydrodynamic Modeling | Sung-Chan Kim; Carl F. Cerco; Billy H. Johnson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 2 | 2006 | 103 - 114 | Three-dimensional Management Model for Lake Washington, Part I: Introduction and Hydrodynamic Modeling | A three-dimensional hydrodynamic model, CH3D-Z (curvilinear hydrodynamics in three dimension, Z-grid version), was implemented in Lake Washington as a part of a management model. The model was calibrated for hydrothermal distribution over a one-year time period for 1995 and verified for a two-year time period between 1996 and 1997. Simulation reproduced intra-annual variation of mixing represented by fall/winter mixing and spring/summer stratification. The simulated variation of vertical thermal structures also matched observation. Vertical flux was investigated in terms of stratification through turbulent mixing and internal waves. Basin scale internal waves showed a characteristic diurnal variation and modulation by surface wind. The model resolved the seasonal variation of thermal structures, assuring a good linkage to a nutrient-eutrophication model. |
| Comparison of Multiple Point and Composite Sampling for Monitoring Bathing Water Quality | Julie L. Kinzelman; Alfred P. Dufour; Larry J. Wymer; Gareth Rees; Kathy R. Pond; Robert C. Bagley | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 2 | 2006 | 95 - 102 | Comparison of Multiple Point and Composite Sampling for Monitoring Bathing Water Quality | The United States Environmental Protection Agency's Beaches Environmental Assessment and Coastal Health Act (BEACH Act) requires states to develop monitoring and notification programs for recreational waters using approved bacterial indicators. Implementation of an appropriate monitoring program can, under some circumstances, be expensive. This study explored the use of composite sampling at two Racine, Wisconsin beaches over a four month period (n = 68 days) to determine whether compositing can provide a valid, unbiased, and cost-effective measure of water quality. Multiple point sampling occurred throughout the bathing season, with water samples collected daily from three or four fixed locations along each beach. From each individual sample, well-mixed aliquots were combined to form a composite sample. Individual and composite samples were assayed identically for Escherichia coli using Colilert-18 and Quanti-Tray 2000 (IDEXX Laboratories, Inc., Westbrook, ME). Results from this study indicate a reasonable expectation of a simple 1:1 ratio between the composite samples and the arithmetic mean of the individual samples. Additionally, log variance of the composite sample results did not differ significantly from that of the single sample averages (p > 0.2). Empirical values for log standard deviations varied by no more than 7% between the composite sample and individually assayed samples. Thus compositing, as performed in this study, appears to introduce neither significant bias nor additional variability into the monitoring results and stands as a reasonable alternative to data sets derived from single-sample methods. Regulatory programs adopting this approach could maintain sample integrity while reducing costs associated with recreational water quality assessment. |
| Natural Variability in Lakes and Reservoirs Should be Recognized in Setting Nutrient Criteria | Matthew F. Knowlton; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 2 | 2006 | 161 - 166 | Natural Variability in Lakes and Reservoirs Should be Recognized in Setting Nutrient Criteria | Long-term data on total phosphorus (TP) and chlorophyll (Ch1) from statewide summer monitoring of Missouri reservoirs (n=p141) and daily collections from 6 summer seasons from Lake Woodrail (n=705) illustrate the magnitude of temporal variability in regional impoundments and the problem of assessing compliance with numeric nutrient criteria. Among individual observations, >24% of Chl values and >14% of TP values were >150% of long-term means in both data sets. Seasonal means varied by ~2-fold among years in Woodrail and by >3-fold in many reservoirs statewide. Simulated numeric criteria of 27 μg/L TP and 10 μg/L Chl were exceeded by 18-24% of individual measurements and 16-24% of seasonal means from reference reservoirs whose long-term means met these criteria. Seasonal mean values based on a single summer misclassified 15-17% of Missouri reservoirs with respect to the status of their long-term averages (8 or more seasons). Given this level of temporal variation, numeric criteria determined from average conditions in reference lakes should be applied only to long-term averages in target lakes. Rules for assessing compliance with nutrient standards should be framed with anticipation of the widely varying conditions in individual lakes. |
| Determining Ecoregional Reference Conditions for Nutrients, Secchi Depth and Chlorophyll a in Kansas Lakes and Reservoirs | Walter K. Dodds; Edward Carney; Robert T. Angelo | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 2 | 2006 | 151 - 159 | Determining Ecoregional Reference Conditions for Nutrients, Secchi Depth and Chlorophyll a in Kansas Lakes and Reservoirs | Baseline environmental conditions are a critical consideration in the development of scientifically defensible aquatic nutrient criteria. We applied three methods to ecoregionally stratified data to determine reference conditions in Kansas lakes and reservoirs with respect to total phosphorus, total nitrogen, Secchi depth, and planktonic chlorophyll a (chl a). First, minimally developed lake/watershed units were identified based on existing geographical databases and visual basin surveys. Lakes and reservoirs in these watersheds were considered minimally-to-least impacted “reference†waters. Second, median nutrient, Secchi depth, and chl a values were determined for the best one-third of lakes and reservoirs and applied as indicators of reference condition (trisection). Third, a regression-based extrapolation method was applied to estimate water quality conditions in the absence of anthropogenic influences. The first method suggested no ecoregional effect on the trophic status of minimally impacted reference water bodies, whereas the other two methods indicated some significant ecoregional differences. Lack of ecoregional effect in reference bodies could indicate that differences were driven by anthropogenic influences rather than natural regional characteristics. Reference conditions, as determined by these three methods, broadly agreed for all parameters and were generally at or less than literature values for the mesotrophic-eutrophic threshold for lakes and reservoirs worldwide. Reference values for total phosphorus were primarily less than levels commonly associated with cyanobacterial blooms. Overall, the data suggest that multiple methods can be used to determine reference condition, and that in Kansas lakes and reservoirs reference condition corresponds to mesotrophic state. |
| Total Coliform and Escherichia Coli Counts in 99 Florida Lakes with Relations to Some Common Limnological Factors | Mark V. Hoyer; Jennifer L. Donze; Eric J. Schulz; Daniel J. Willis; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 2 | 2006 | 141 - 150 | Total Coliform and Escherichia Coli Counts in 99 Florida Lakes with Relations to Some Common Limnological Factors | The degree of bacterial contamination of 99 Florida lakes was studied using total coliform and Escherichia coli (E. coli) counts as indicators. Over 75% of the 4055 samples analyzed for total colifoms and over 98% analyzed for E. coli were below Florida's state standards for total and fecal coliform bacteria, respectively. Thus, there is little evidence of widespread fecal contamination in the Florida lakes examined during this study. Future bacterial sampling in lake systems should consider the facts that open-water samples had significantly lower total coliform and E. coli counts than littoral samples, and that the variance in bacterial counts is greater among lakes over time than spatially within lakes. Additionally, lake trophic status and aquatic bird abundance were also positively related to both total coliform and E. coli counts, while lake surface area and percent area covered with aquatic macrophytes (PAC) showed no significant relations. The method of waste management around lakes is often a concern to many people citing septic tank systems for polluting aquatic systems. However, the data examined in this study showed no difference in bacterial counts between lakes managing waste with septic tanks and those with central waste water treatment systems. A routine, inexpensive bacterial monitoring program is recommended for lakes used for body-contact recreational activities to be safe and relieve concerns of the public about potential health problems. |
| Three-dimensional Management Model for Lake Washington, Part II: Eutrophication Modeling and Skill Assessment | Carl F. Cerco; Mark R. Noel; Sung-Chan Kim | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 2 | 2006 | 115 - 131 | Three-dimensional Management Model for Lake Washington, Part II: Eutrophication Modeling and Skill Assessment | The CE-QUAL-ICM 3-dimensional eutrophication model was applied to Lake Washington for the period 1995-1997. Transport processes were obtained from the companion CH3D-WES hydrodynamic model. The model activated 18 state variables in the water column, including physical variables; phytoplankton; multiple forms of carbon, nitrogen, and phosphorus; dissolved oxygen; and fecal coliform. The water column was coupled to a sediment diagenesis model that computed sediment-water fluxes of dissolved oxygen, methane, ammonium, nitrate, and phosphate, based on computed inputs of particulate organic matter. The model successfully computed the annual cycles and spatial distributions of key water quality components. Nutrient loads were calculated and nutrient budgets were constructed as part of the model exercise. Load sources included river inflows, distributed loads, sewer overflows and atmospheric loading. The Sammamish River was identified as the largest source of nutrients to Lake Washington, followed by the Cedar River and other distributed sources. The majority of the nutrient load is deposited in the sediments. A lesser amount leaves via Lake Union. Our nutrient loads were 30% (nitrogen) to 60% (phosphorus) higher than the loads from the late 1970s. |
| A Review of Factors Affecting the Distribution and Abundance of Rainbow Trout (Oncorhynchus mykiss Walbaum) in Lake and Reservoir Systems | Stephen Swales | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 2 | 2006 | 167 - 178 | A Review of Factors Affecting the Distribution and Abundance of Rainbow Trout (Oncorhynchus mykiss Walbaum) in Lake and Reservoir Systems | Rainbow trout distribution and abundance in lakes and reservoirs has been correlated with a wide range of physical, chemical and biological factors. In North American lakes and reservoirs, distribution and abundance are affected by variables such as lake elevation, water chemistry, and lake morphology, as well as biological factors such as food availability and competition with other fish species. Chemical and physical features that serve as indices of biological productivity, including pH, alkalinity, total dissolved solids and morpho-edaphic index, have been related positively to trout abundance. Rainbow trout occurrence and distribution in lakes and reservoirs is determined mostly by a combination of factors, notably the concentration of dissolved oxygen, water temperature and food. The upper water temperature threshold for rainbow trout habitat in lakes is generally around 21°C, while a dissolved oxygen concentration of 2.5 mg L-1 is generally taken as the lower limit for distribution. |
| Analysis of Environmental Variation in a Great Plains Reservoir Using Principal Components Analysis and Geographic Information Systems | James M. Long; William L. Fisher | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 2 | 2006 | 132 - 140 | Analysis of Environmental Variation in a Great Plains Reservoir Using Principal Components Analysis and Geographic Information Systems | We present a method for spatial interpretation of environmental variation in a reservoir that integrates principal components analysis (PCA) of environmental data with geographic information systems (GIS). To illustrate our method, we used data from a Great Plains reservoir (Skiatook Lake, Oklahoma) with longitudinal variation in physicochemical conditions. We measured 18 physicochemical features, mapped them using GIS, and then calculated and interpreted four principal components. Principal component 1 (PC1) was readily interpreted as longitudinal variation in water chemistry, but the other principal components (PC2-4) were difficult to interpret. Site scores for PC1-4 were calculated in GIS by summing weighted overlays of the 18 measured environmental variables, with the factor loadings from the PCA as the weights. PC1-4 were then ordered into a landscape hierarchy, an emergent property of this technique, which enabled their interpretation. PC1 was interpreted as a reservoir scale change in water chemistry, PC2 was a microhabitat variable of rip-rap substrate, PC3 identified coves/embayments and PC4 consisted of shoreline microhabitats related to slope. The use of GIS improved our ability to interpret the more obscure principal components (PC2-4), which made the spatial variability of the reservoir environment more apparent. This method is applicable to a variety of aquatic systems, can be accomplished using commercially available software programs, and allows for improved interpretation of the geographic environmental variability of a system compared to using typical PCA plots. |
| Assessment of Long-term Trends in the Oxygen Resources of a Recovering Urban Lake, Onondaga Lake, New York | David A. Matthews; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 1 | 2006 | 19 - 32 | Assessment of Long-term Trends in the Oxygen Resources of a Recovering Urban Lake, Onondaga Lake, New York | Long-term trends in dissolved oxygen (DO) resources are documented for ionically enriched, hypereutrophic Onondaga Lake, New York, for 1978-2002. Assessments of oxygen resources are based on DO profiles of 1 m resolution conducted hourly to weekly during April-October. Closure of an industry that operated on the lake's shore until 1986 resulted in an abrupt decrease in primary production and organic carbon deposition and marked changes in hypolimnetic and epilimnetic DO regimes. The hypolimnetic DO response was gradual, reflecting the influence of sediment feedback. The onset of complete hypolimnetic anoxia, which occurred by early June through the 1980s, took place approximately one month later over 1997-2002. The anoxic factor decreased significantly over the study interval, from 97±5 d to 67±2 d. Epilimnetic DO concentrations responded rapidly to the abrupt change in lake metabolism. Before closure of the industry, 41% of the April to mid-September DO observations deviated from saturation concentrations by >30%. In the years immediately following industry closure, this degree of disequilibrium occurred in 23% of DO observations. Percent saturation values during fall turnover increased gradually during the study, from 49±2 to 65±2. DO concentrations in the lake's upper waters have been subject to substantial diel fluctuations (>4 mg/L), with daily minima and maxima generally occurring at approximately 7:00 and 16:00, respectively. Measurements made at 11:00 and 22:00 were most likely to be representative of daily average conditions. Diel variations and sampling frequency were demonstrated to be important issues for the evaluation of status with respect to water quality standards for DO. Levels of DO in the lake's upper waters have been positively correlated with chlorophyll a concentrations (r = 0.52). Despite marked improvements in DO resources, the lake continues to lack cool, well-oxygenated waters during summer necessary to support coldwater fish species. |
| Resolution of Turbidity Patterns from Runoff Events in a Water Supply Reservoir, and the Advantages of In Situ Beam Attenuation Measurements | Steven W. Effler; Anthony R. Prestigiacomo; Feng Peng; Katerina B. Bulygina; David G. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 1 | 2006 | 79 - 93 | Resolution of Turbidity Patterns from Runoff Events in a Water Supply Reservoir, and the Advantages of In Situ Beam Attenuation Measurements | The impact of runoff events on light scattering, or turbidity, levels in a water supply reservoir, and the comparative performance of three surrogate metrics of light scattering, are documented for the spring through fall interval of a high runoff year. The analysis is supported by: (1) frequent (42 d) field measurements of the beam attenuation coefficient at 660 nm (c660) and “optical†backscattering (OBS) collected with rapid profiling instrumentation at multiple sites; (2) laboratory measurements of c660 and turbidity (Tn); and (3) characterizations of inorganic particles with scanning electron microscopy interfaced with automated image and X-ray analyses. Conspicuous increases in light scattering levels are reported following runoff events, as reflected in increases in c660, OBS and Tn, associated with terrigenous inputs of clay minerals. The extent of this impact is demonstrated to be driven by the magnitude of the runoff event. Terrigenous inputs of turbidity are shown to enter as density currents, which travel the entire length of the reservoir for major runoff events, manifested as peak scattering levels in subsurface layers. Strong longitudinal and lateral differences are documented soon after runoff peaks. Scattering levels and spatial gradients are shown to diminish rapidly, with pre-event conditions approached within a week. Systematically lower c660 values are reported for laboratory measurements compared to in situ observations, particularly at high scattering levels, consistent with the operation of particle coagulation. In situ measurement of c660is identified as the preferred surrogate metric of light scattering. |
| A DNA Fingerprinting Approach for Distinguishing Native and Non-native Milfoils | Ryan A. Thum; Jay T. Lennon; Jody Connor; Amy P. Smagula | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 1 | 2006 | 1-6 | A DNA Fingerprinting Approach for Distinguishing Native and Non-native Milfoils | Variable-leaf water milfoil, Myriophyllum heterophyllum, is a non-native aquatic plant that has become a major management concern in New England. One key obstacle for effective management is accurate identification of native and non-native milfoil species. We used DNA sequences from the nuclear ribosomal DNA internal transcribed spacers (ITS) to identify non-native populations of M. heterophyllum. We found a number of discrepancies among morphological and genetic identifications, including individuals that were morphologically identified as natives but genetically identified as non-natives, and vice versa. We attribute these discrepancies to inaccurate identifications arising from morphological similarities among milfoil species. To help remedy this problem, we developed a restriction enzyme assay that distinguishes non-native M. heterophyllum from native milfoils. The assay provides a reliable method for identifying M. heterophyllum and therefore should facilitate lake management decisions concerning native and non-native milfoil populations. |
| A Review of the Components, Coefficients and Technical Assumptions of Ontario's Lakeshore Capacity Model | A. M. Paterson; P. J. Dillon; N. J. Hutchinson; M. N. Futter; B. J. Clark; R. B. Mills; R. A. Reid; W. A. Scheider | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 1 | 2006 | 7-18 | A Review of the Components, Coefficients and Technical Assumptions of Ontario's Lakeshore Capacity Model | Phosphorus is the nutrient that most often limits the primary productivity of inland lakes on the Precambrian Shield. Recognizing the need to develop quantitative relationships to assess the impact of shoreline development on phosphorus concentrations in lakes, the Lakeshore Capacity Model (LCM) was developed by the Ontario Ministry of the Environment, Canada. The LCM is a steady-state mass-balance model that uses empirical relationships to predict the ice-free total phosphorus concentration of a lake. The model, calibrated and tested on lakes on the Precambrian Shield, has subsequently formed the basis for management decisions in the public and private sectors. Over the past two decades the coefficients, input parameters and assumptions of the LCM have been modified and updated to reflect an improved scientific understanding of the relative importance of sources and losses of phosphorus in lakes and watersheds. Here we present a comprehensive review of the components, coefficients and assumptions of the most recent version of the LCM (v. 3.0), providing a standard reference for all users of the model. |
| Predicting Sediment Physical Properties within a Montane Lake Basin, Southern Coast Mountains, British Columbia, Canada | Erik Schiefer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 1 | 2006 | 69 - 78 | Predicting Sediment Physical Properties within a Montane Lake Basin, Southern Coast Mountains, British Columbia, Canada | The variability of lacustrine sediment physical properties was examined for a small montane lake in the southern Coast Mountains of British Columbia. A high-density sampling scheme (1 core per 0.01 km2) was utilized for sediment sampling within the 2 km2 lake basin. Vertical patterns in the upper sediment record were controlled by compaction effects with interruptions by major sediment delivery event beds and organic debris deposits. Primary patterns of lateral variability were associated with proximity to the principal lake inflow. A simple sedimentation model based on Stokes Law was shown to reasonably predict down-lake variations of sediment texture. A significant influence of water depth was observed in shallow water settings where highly variable sediment characteristics were observed. Secondary spatial patterns were related to localized rapid deposition effects and past land-use activities. Sedimentary parameters of water content, bulk density, organic content, and particle size were shown to be interrelated to varying degrees. Water content may be used as a key parameter for predicting other physical properties because of its strong negative relation with sediment density, moderate positive relation with organic content, and non-linear association with mean particle size. |
| Spatial and Temporal Dynamics of Microcystin in a Missouri Reservoir | Jennifer L. Graham; John R. Jones; Susan B. Jones; Thomas E. Clevenger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 1 | 2006 | 59 - 68 | Spatial and Temporal Dynamics of Microcystin in a Missouri Reservoir | Environmental factors associated with spatiotemporal variation of microcystin (MC) in Mozingo Lake, a Missouri reservoir, were studied during summer 2001, and annual MC trends were characterized from May 2001-May 2002. MC increased during summer, ranging from 20 to1220 ng/L. Seasonal patterns in MC corresponded with chlorophyll >35 μm (Net Chl) and cyanobacterial biovolume associated with increased dominance by Microcystis and Anabaena. MC showed strong negative correlations with dissolved nitrogen (r=-0.95) and cations (r=-0.98), and strong positive correlations with Net Chl (r=0.91). Once the lake stratified, MC and Net Chl remained uniform throughout the photic zone and decreased significantly (p<0.05) in the aphotic zone. Field experiments indicated MC did not change independently of Net Chl in response to decreased light or increased nutrients; however, enclosure effects may have substantially influenced experimental results. Mozingo Lake MC was tightly coupled with seasonal lake processes, including stratification and nutrient loss from the epilimnion, and cyanobacterial community composition, abundance and distribution in the water column. MC was detected in all monthly samples suggesting the potential for problems associated with MC exists year round, but peaks in early fall presented the greatest concern in Mozingo Lake. |
| Variation in Water Quality and Phytoplankton Nutritional Status in an Urbanized Lake System (Lake Merced, California, USA) | Albert M. Marchi; Hunter J. Carrick | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 1 | 2006 | 33 - 43 | Variation in Water Quality and Phytoplankton Nutritional Status in an Urbanized Lake System (Lake Merced, California, USA) | Lake chemistry is influenced by land use in the surrounding watershed, particularly in complex urban landscapes, which are commonly subjected to an increase in material loadings. Because land use is rarely uniform, individual ecosystems embedded within the landscape may reflect varying water quality conditions. The Lake Merced system is composed of three lake basins with watersheds (surface area = 13 km2) residing entirely within the city of San Francisco, California. On nine occasions from January-June 1995 we sampled the two main lakes (North and South Lake Merced) within the system to evaluate their relative productivity and nutrient status. On each date, several physical-chemical conditions were measured, and nutrient enrichment bioassays were performed to evaluate the nutritional status of the phytoplankton (nitrogen (N) and phosphorus (P) enrichment in a 2 2 factorial experimental design). All the parameters tested except temperature were higher in the north lake compared with the south (pair-wise Wilcoxon Ranked sums), and common trophic state variables were more than 2-fold higher in the north lake. Phytoplankton growth in North Lake Merced was N-limited while growth in South Lake Merced was co-limited by N and P. In sum, our data indicate that differences among these lakes may be explained by simple volume differences between lakes (with the smaller North Lake Merced being more eutrophic), and heavy stocking of fishes to the north lake. Particulate nutrient ratios (N:P) were good indicators of phytoplankton nutritional status throughout the system, while N:P ratios based on total nutrient concentrations gave misleading results. |
| Cultural Eutrophication Trends in Three Southeastern Ontario Lakes: A Paleolimnological Perspective | Euan D. Reavie; Kimberley E. Neill; Joanne L. Little; John P. Smol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 22 | 1 | 2006 | 44 - 58 | Cultural Eutrophication Trends in Three Southeastern Ontario Lakes: A Paleolimnological Perspective | Three southeastern Ontario lakes have responded differently to human disturbances in their catchments over the past 150 years. Catchments of Round and Long lakes were once subjected to deforestation and apatite mining but currently have no local watershed disturbances. Meanwhile, Hambly Lake has been surrounded by residences since the 1950s. Subfossil chironomid head capsules and diatom valves were identified and enumerated in sediment cores from Hambly and Round lakes, and diatom remains were analyzed from Long Lake sediments. Quantitative reconstructions for chironomid-inferred average hypolimnetic dissolved oxygen (CIDO) and diatom inferred total phosphorus (DITP) were performed. Paleolimnological data indicated that Round Lake was subject to considerable human impacts in the late-1800s, with a dramatic shift from oligotrophic to mesotrophic and eutrophic diatom taxa and the onset of hypolimnetic anoxia. In the past 60 years (ca. 1945-present), Round Lake reverted to pre-anthropogenic settlement conditions in response to the cessation of human activities in the catchment. Long Lake microfossils revealed similar trends to those recorded in Round Lake, probably due to a similar disturbance history and its close geographic proximity. In contrast to the other two study sites, Hambly Lake was naturally mesotrophic prior to human settlement, and despite the development of numerous cottages and residences in the catchment, only minor shifts to slightly more eutrophic chironomid and diatom assemblages occurred. Higher nutrients and hypolimnetic anoxia appear to be natural conditions, and consequently little additional change occurred after the arrival of European settlers. This study illustrates the importance of obtaining long-term data for identifying background limnological conditions when assessing impacts and developing management plans. |
| Community Structure and Environmental Conditions in Florida Shallow Lakes Dominated by Submerged Aquatic Vegetation | Binhe Gu; Mark V. Hoyer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 403 - 410 | Community Structure and Environmental Conditions in Florida Shallow Lakes Dominated by Submerged Aquatic Vegetation | Florida inland waters are dominated by shallow lakes, many of which support the growth of submerged aquatic vegetation (SAV). We examined the species composition and selected environmental variables of SAV-dominated lakes using data from the Florida LAKEWATCH program. Our analysis revealed eight genera with approximately 15 species of SAV among these shallow lakes, which range in size from <2-2,300 ha. The SAV community within each lake primarily consisted of a single or a few species. Utricularia and Hydrilla were the most common SAV genera found in these lakes. Many SAV species grew well in a wide range of water quality conditions, although biodiversity and biomass tended to increase with increasing alkalinity and calcium concentration. More SAV species were also found in lakes with higher pH and Secchi depth. On average, Ceratophyllum, Najas and Vallisneria dominated lakes with high total phosphorus (TP) concentrations (0.034-0.053 mg/L) while Chara, Utricularia, Potamogeton and Myriophyllum corresponded with relatively low TP concentrations (0.008-0.013 mg/L). However, there was a large overlap in nutrient concentrations in lakes dominated by different species. |
| Effects of Protective Limestone Treatment on Water Chemistry and Fisheries Management in Laurel Bed Lake, Virginia | Daniel M. Downey; Thomas M. Hampton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 411 - 422 | Effects of Protective Limestone Treatment on Water Chemistry and Fisheries Management in Laurel Bed Lake, Virginia | Dolomitic limestone additions to the acidic water of Laurel Bed Lake in southwestern Virginia have resulted in significant improvements in both the water quality and fishery. Pretreatment water quality showed the lake and its tributary to have high acidity with pH near or <5.0; negative acid neutralizing capacity (ANC) values; aluminum concentrations (AlT) > 150 μg/L; and low calcium to hydronium (Ca/H) ratios. The acidity is the result of atmospheric acid deposition, natural acidity from wetland origins and lack of carbonate-bearing minerals in the watershed. Limestone treatments have achieved target pH >6.5, ANC >100 μeq/L, AlT <60 μg/L and Ca/H >600. Iron and trace element concentrations have decreased. The dose-mass and frequency of limestone treatment to maintain circumneutral conditions has been found to be 150 tons introduced at two year intervals. Prior to implementation of this project, rock bass (Ambloplites rupestris) were overabundant and stunted (mean Total Length (TL) = 155 mm). The lake was drained, and the rock bass were removed. Stocked fingerling brook trout (Salvelinus fontinalis) survived and grew well following lake liming. Smallmouth bass (Micropterus dolomieu), stocked in response to the recurrence of rock bass, also performed well. An angler survey suggested that both species were important to the lake's fishery. The lake is now managed as a catch-and-release fishery for smallmouth bass and a put-and-grow fishery for brook trout. |
| Cyanobacterial Proliferation is a Recent Response to Eutrophication in Many Florida Lakes: A Paleolimnological Assessment | Melanie A. Riedinger-Whitmore; Thomas J. Whitmore; Joseph M. Smoak; Mark Brenner; Allen Moore; Jason Curtis; Claire L. Schelske | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 423 - 435 | Cyanobacterial Proliferation is a Recent Response to Eutrophication in Many Florida Lakes: A Paleolimnological Assessment | Cyanobacteria dominate many highly productive Florida lakes. Algal proliferation often is attributed to eutrophication during the last century, but it is poorly documented because Florida's water-quality monitoring programs became common only after 1980. We interpret paleolimnological data from the sediment cores of 6 productive lakes to determine when cyanobacterial proliferation first occurred, and whether it resulted from natural edaphic influence or from eutrophication caused by human activities. Major algal-pigment groups in sediments were analyzed using pigment-extraction and spectrophotometric techniques. Pigment profiles are compared with WACALIB-derived inferences for limnetic total-P, limnetic chlorophyll a, and trophic-state index values based on sedimented diatoms, and with stable isotope (δ13C & δ15N) signatures of organic matter. Cyanobacterial and algal proliferation increased during recent decades in 5 of the 6 study lakes in response to eutrophication. Two lakes demonstrated some evidence of recovery following nutrient-mitigation programs that reduced sewage and other point-source inputs. Five lakes showed intermittent to moderate cyanobacteria presence in the bottom portion of their cores because of edaphic nutrient supply or early watershed disturbance. One highly productive lake showed no evidence of eutrophication and demonstrated that dense cyanobacterial populations can occur naturally. Relationships were particularly strong among sedimented pigment profiles and diatom-inferred limnetic water-quality profiles. Although cyanobacteria have long-standing presence in some naturally productive Florida lakes, our studies suggest that algal proliferation in many lakes is both recent and abrupt in response to eutrophication. Paleolimnological methods are informative about the timing and causes of cyanobacterial appearance in regions where long-term water-quality data are lacking. |
| Landsat-based Remote Sensing of Lake Water Quality Characteristics, Including Chlorophyll and Colored Dissolved Organic Matter (CDOM) | Patrick Brezonik; Kevin D. Menken; Marvin Bauer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 373 - 382 | Landsat-based Remote Sensing of Lake Water Quality Characteristics, Including Chlorophyll and Colored Dissolved Organic Matter (CDOM) | Ground-based measurements on 15 Minnesota lakes with wide ranges of optical properties and Landsat TM data from the same lakes were used to evaluate the effect of humic color on satellite-inferred water quality conditions. Color (C440), as measured by absorbance at 440 nm, causes only small biases in estimates of Secchi disk transparency (SDT) from Landsat TM data, except at very high values (> ~ 300 chloroplatinate units, CPU). Similarly, when chlorophyll a (chl a) levels are moderate or high (> 10 μg/L), low-to-moderate levels of humic color have only a small influence on the relationship between SDT and chl a concentration, but it has a pronounced influence at high levels of C440 (e.g., > ~200 CPU). However, deviations from the general chl a-SDT relationship occur at much lower C440 values (~ 60 CPU) when chl a levels are low. Good statistical relationships were found between optical properties of lake water generally associated with algal abundance (SDT, chl a, turbidity) and measured brightness of various Landsat TM bands. The best relationships for chl a (based on R2 and absence of statistical outliers or lakes with large leverage) were combinations of bands 1, 2, or 4 with the band ratio 1:3 (R2 = 0.88). Although TM bands 1-4 individually or as simple ratios were poor predictors of C440, multiple regression analyses between ln(C440) and combinations of bands 1-4 and band ratios yielded several relationships with R2 ≥ 0.70, suggesting that C440 can be estimated with fair reliability from Landsat TM data. |
| Life-history Responses of Daphnia pulex with Exposure to Aluminum Sulfate | Louise A. Wold; Barry C. Moore; Nairanjana Dasgupta | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 383 - 390 | Life-history Responses of Daphnia pulex with Exposure to Aluminum Sulfate | Life table experiments with ten Daphnia clones were conducted to assess responses to three concentrations (0.05 mg 1-1 A1, 0.30 mg 1-1 A1, and 0.50 mg 1-1 A1) of aluminum sulfate (alum), reflecting a general range that might be encountered in lake restoration treatments. Alum is frequently employed for phosphorus inactivation in lake restoration and management applications. Experimental Daphnia clones originated from a lake currently being treated with alum, from a lake treated with alum over twenty years ago, and from a pond with no prior alum additions. When exposed to laboratory alum-conditioned media, clones from the lake with ongoing alum treatment exhibited higher age-specific survivorship, higher fecundity, and faster growth rates compared with clones having less recent or no prior exposure. Our results suggest the possibility that Daphnia may exhibit adaptive strategies that heighten survivorship and fecundity when exposed to sub-lethal chemical stresses. Results also indicate that clone origin and previous exposure to chemicals is an important consideration in Daphnia bioassays. |
| Introduction Pathways, Differential Survival of Adult and Larval Zebra Mussels (Dreissena polymorpha), and Possible Management Strategies, in an Adirondack Lake, Lake George, NY | Marc E. Frischer; Brian R. McGrath; Andrew S. Hansen; Paul A. Vescio; Jane A. Wyllie; John Wimbush; Sandra A. Nierzwicki-Bauer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 391 - 402 | Introduction Pathways, Differential Survival of Adult and Larval Zebra Mussels (Dreissena polymorpha), and Possible Management Strategies, in an Adirondack Lake, Lake George, NY | The introduction pathway and source of zebra mussel larvae into Lake George, NY were determined and a general bioassay was developed to assess the zebra mussel colonization risk of a water body. The presence of zebra mussel larvae (veligers), recruitment, and adults were monitored in Lake George from 1995-2003. All observations of zebra mussel veligers were at marinas, boat ramps, or areas heavily used by fishing boats. Models and observation suggest that human activity is the primary mechanism by which zebra mussels are transported overland. Although one small colony of zebra mussels was discovered during this period, no evidence was found of recruitment or permanent colonization by zebra mussels in Lake George. A series of bioassays to assess both larval and adult growth and survival was developed and indicated that Lake George water limited the survival of zebra mussel larvae but not of adults. These bioassays confirmed model predictions that zebra mussel recruitment is limited by the moderate water alkalinity in Lake George, but that adults were able to survive and grow. The unique water chemistry that limits zebra mussel colonization, and the close proximity of Lake George to other mussel-populated waters, make Lake George an ideal natural laboratory to study the introduction process of zebra mussel adults and/or larvae into a landlocked lake. Although zebra mussels have colonized the major waterways of Eastern North America, the establishment of zebra mussel populations in landlocked lakes is occurring much more slowly. Public outreach and education efforts that appear to aid in limiting the introduction of zebra mussels are also discussed. |
| Long-term Limnological Changes in Six Lakes with Differing Human Impacts from a Limestone Region in Southwestern Ontario, Canada | Petra Werner; Michelle Chaisson; John P. Smol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 436 - 452 | Long-term Limnological Changes in Six Lakes with Differing Human Impacts from a Limestone Region in Southwestern Ontario, Canada | Diatom-based paleolimnological techniques have been used to track limnological changes over the last ~150 years in six oligomesotrophic, primarily shallow, hardwater lakes in southwestern Ontario. Three of the six lakes are located in national parks and consequently have had little-to-no direct human impacts in their watersheds, with the exception of logging following initial European settlement (A.D. ~1850-1910). The paleolimnological indicators suggest that these activities have led to subtle-to-moderate eutrophication and possibly a reduction of macrophyte abundances. Additional subtle limnological changes have been occurring over the last century even in the undisturbed control lakes. The marked increase of Cyclotella comensis suggests that alkalinity levels may have increased ~1950-1980. The remaining three lakes experienced additional disturbances following the 19th century logging. For example, a campsite has been located on the shore of Cyprus Lake since 1968, but study results indicate this minor disturbance did not significantly alter water quality. In contrast, the last two of the six study lakes have experienced significantly more intense human impact and showed markedly different trophic histories. For example, the catchment of Chesley Lake was heavily developed for agriculture, the shoreline was densely populated with cottages and macrophytes were deliberately removed from the littoral zone. The paleolimnological data recorded a reduction of the water quality following these disturbances. Cage aquaculture has been ongoing in Lake Wolsey since 1983. Diatom changes in the lake's recent sediment are consistent with increased nutrient concentrations. Collectively, these paleolimnological data provide lake managers with important historical data from which trajectories of past limnological changes can be inferred and realistic mitigation targets can be identified. |
| Book Reviews | James F. LaBounty | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 474 | Book Reviews | |
| Book Reviews | James F. LaBounty | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 474 - 475 | Book Reviews | |
| Factors that Influence Phosphorus, Filamentous Cyanobacteria and Odor in McDaniel Lake, a Southwest Missouri Water Supply Reservoir, 1983–2002 | Norman W. Youngsteadt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 453 - 464 | Factors that Influence Phosphorus, Filamentous Cyanobacteria and Odor in McDaniel Lake, a Southwest Missouri Water Supply Reservoir, 1983-2002 | McDaniel Lake is a 1.12 km2 water supply reservoir subject to occasional taste and odor problems. This paper reviews data for 1983-2002, with a focus on summer, and uses regression analysis to identify predictors of lake phosphorus concentration, cyanobacteria filament concentration and odor production. Cattle were identified as the main source of excess tributary phosphorus, but lake phosphorus was significantly influenced by factors other than tributary phosphorus, including lake level, lake bottom temperature and wind. Likewise, cyanobacteria filament concentration was significantly influenced by factors other than lake phosphorus, including sunshine, air temperature and lake-bottom temperature. Odor (methylisoborneol plus geosmin) production was most strongly associated with high cyanobacteria filament counts and abundant sunshine. |
| Surface Seiche and Wind Set-up on Lake Okeechobee (Florida, USA) During Hurricanes Frances and Jeanne | Michael J. Chimney | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 4 | 2005 | 465 - 473 | Surface Seiche and Wind Set-up on Lake Okeechobee (Florida, USA) During Hurricanes Frances and Jeanne | Hurricanes Frances and Jeanne (HF and HJ) passed over Lake Okeechobee, Fla., in September 2004. Strong winds produced a large surface seiche during both storms. The slope of the water surface reversed itself within 4 hrs as wind direction changed during HF, but shifted in only 2 hrs during HJ. The greatest water level difference was along the lake's north-south (N-S) axis during both storms (2.6 and 3.5 m, respectively). Differences between maximum wind set-up (storm surge) and set-down on the opposite shore indicated that the slope of the water surface was not symmetrical at the height of either storm. Using simple steady-state models, maximum wind set-up was forecast for opposing stations along the lake's N-S axis and compared to observed data and storm surge predictions by the SLOSH model. Steady-state model accuracy was not improved by using averaging periods >15 min in length or by lagging weather and water temperature data behind lake stage. Steady-state models calibrated to the data performed better than uncalibrated models. Prediction errors for maximum wind set-up during HF and HJ by SLOSH were comparable to errors in the steady-state models. While not a substitute for sophisticated hydrodynamic models like SLOSH and LOHM, properly calibrated steady-state models can provide lake managers with reasonable estimates of wind set-up. Future use of simple wind set-up models on Lake Okeechobee will require validation against data from other hurricanes. |
| A Simplified Assessment of Factors Controlling Phosphorus Loading from Oxygenated Sediments in a Very Shallow Eutrophic Lake | Nadia Kelton; Patricia Chow-Fraser | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 223 - 230 | A Simplified Assessment of Factors Controlling Phosphorus Loading from Oxygenated Sediments in a Very Shallow Eutrophic Lake | Factors controlling the release of bioavailable soluble reactive phosphorus (SRP) from sediments in very shallow lakes are not fully understood. Our approach involved relatively simple measurements of four factors affecting the calculation of internal phosphorus load: the number of sampling sites, sediment freezing, incubation temperature and oxic state in Cootes Paradise Marsh, now a very shallow (Z = 70 cm) eutrophic degraded urban lake in Ontario, Canada. Our results indicate that all of these factors need to be considered when attempting to estimate the internal phosphorus load of a shallow system. The total internal load of phosphorus in Cootes Paradise Marsh was 34% of the total loading (both internal and external), with diffusion from the sediment accounting for 23% of all phosphorus inputs. Large carp are now excluded from the lake and were estimated by difference to have contributed 23% to summer internal loading. |
| The Lake Okeechobee Water Quality Model (LOWQM) Enhancements, Calibration, Validation and Analysis | R. Thomas James; Victor J. Bierman Jr.; Michael J. Erickson; Scott C. Hinz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 231 - 260 | The Lake Okeechobee Water Quality Model (LOWQM) Enhancements, Calibration, Validation and Analysis | The Lake Okeechobee Water Quality Model (LOWQM) was enhanced to more accurately simulate sediment-water phosphorus (P) dynamics by separating the organic P (OP) into four classes (readily degradable, moderately degradable, non-degradable and dissolved), and to more accurately simulate algal dynamics by representing the phytoplankton community with the three distinct major algal groups (cyanobacteria, diatoms and green algae) observed in the lake. The model was calibrated and validated to observed water column nutrient data, sediment nutrient measurements and biovolume data for cyanobacteria, diatoms, and green algae. Model predictions were consistent with experimental observations and indicated that net sediment inorganic P (IP) loads were twice the external TP loads and net sediment inorganic nitrogen (IN) loads were 0.64 times the external total N loads. However, because of organic nutrient and algal settling the lake sediments are an overall nutrient sink. Sensitivity analysis indicated that total algal carbon, algal groups and chlorophyll a were very sensitive to changing algal parameters, parameters affecting light, temperature and supply of IP to the water column. Nutrients were less sensitive for two reasons: 1) algae represent a small fraction of the total nutrient mass, 2) the large pools of sediment nutrients, with long turnover times, buffer changes in the water column. Sensitivity analysis pointed to three potential management options to improve lake water quality: dredging, chemical treatment of sediments and external load reduction. These options were previously considered in a large sediment management feasibility study, which concluded that the last option-load reduction-was the most viable. |
| Internal Nutrient Loads from Sediments in a Shallow, Subtropical Lake | M. M. Fisher; K. R. Reddy; R. Thomas James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 338 - 349 | Internal Nutrient Loads from Sediments in a Shallow, Subtropical Lake | Fluxes of dissolved inorganic nitrogen, DIN, (as ammonia, NH4-N) and phosphorus (as dissolved reactive phosphorus, DRP) from the sediments to the water column of Lake Okeechobee were determined from two separate techniques: increases in nutrient concentration in the water column above intact cores and concentration gradients determined with pore water equilibrators. These fluxes were estimated from different sediment types within the lake (sand, peat, mud) and at two major inflows (Kissimmee River and Taylor Creek). DRP release from peat sediments was highest. Measurements in other sediments were not significantly different from each other. DRP flux to the lake was estimated as 326 Mt·yr-1 in 1989 and had increased to 472 Mt·yr-1 in 1999. Because of measurement variation, this increase was not statistically different. These estimates of internal DRP loads are greater than estimated external surface DRP loads that averaged 316 Mt·yr-1 from 1979-1988 and 258 Mt·yr-1 from 1989-1999. DIN flux was highest near Taylor Creek. There was no consistent pattern between sediment type and DIN flux. Internal loads of DIN were estimated in 1999 as 4,500 Mt·yr-1, which is greater than the external surface loads of DIN estimated for the period of 1989-1998, of 896 Mt·yr-1. Sediment oxygen demand measured in the cores was strongly correlated to DRP and DIN flux, indicating that these fluxes are largely a result of mineralization of organic material. This study indicates that sediment diffusive fluxes are a significant source of DRP and DIN to the lake water column. |
| Thermal Stratification and the Potential for Enhanced Phosphorus Release from the Sediments in Lake Okeechobee, USA | A. J. Rodusky; B. Sharfstein; K-R. Jin; T. L. East | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 330 - 337 | Thermal Stratification and the Potential for Enhanced Phosphorus Release from the Sediments in Lake Okeechobee, USA | We inferred the potential importance of enhanced phosphorus (P) release from the sediments during periods of thermal stratification in Lake Okeechobee USA, a large, shallow, eutrophic lake. This was accomplished by determining the frequency and duration of thermal stratification, using monitoring data collected during 1997 and 1999, with multiparameter sondes, which were positioned at a weather platform in the center of the lake. We also monitored dissolved oxygen, pH, specific conductance, turbidity and redox potential, to assess if any relationships existed between these variables and thermal stratification. Thermal stratification was infrequent, documented for 42 and 74 total hours, and occurred for an extrapolated period of at least one hour on approximately 18 days or 5% of both years. Thermal stratification occurred almost exclusively during the summer (May - September), and was brief, typically lasting for one to six hours per event, although there was one event during 1999, where 49 continuous hours of thermal stratification were documented. Dissolved oxygen (DO) concentrations and redox potential (ORP) measurements collected 0.5 m above the sediment surface suggested that the top of the sediment may not have ever become anoxic and was rarely reducing. Chemical characteristics during periods of thermal stratification, compared to those considered favorable for P release based on previous Lake Okeechobee sediment studies, indicate that thermal stratification is usually insufficiently long for chemical conditions (anoxic or low DO and ORP) to develop above the sediment surface that would enable enhanced P release from the sediments. |
| Chlorophyll Response to Nutrients and Non-algal Seston in Missouri Reservoirs and Oxbow Lakes | John R. Jones; Matthew F. Knowlton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 361 - 371 | Chlorophyll Response to Nutrients and Non-algal Seston in Missouri Reservoirs and Oxbow Lakes | When unaggregated summer chlorophyll data (Chl) from 184 Missouri reservoirs are plotted against total phosphorus (TP) a 'bow' in the distribution develops among a group of points with low Chl:TP ratios (averaging <0.05). Low Chl:TP is mostly associated with turbid, nutrient-rich inflows in reservoirs across the entire trophic range. Non-algal seston (NAS) is our best metric of these inflows and is a co-variable in Chl-TP regressions. This influence is most prominent in years of high runoff and is distinctly seasonal, being most prevalent in early summer prior to full stratification. In late summer, inflows typically enter as subsurface density currents, and nitrogen accounts for more variation in Chl-TP than NAS. Neither variable, however, greatly influences the long-term relation between Chl and TP, which is linear, relatively consistent, and matches the global pattern. In several oxbow lakes, high NAS caused by sediment resuspension is a chronic condition; it seems neither light nor flushing greatly influence Chl: TP in these shallow systems, and values approximate the statewide average. Temporal variation in Chl:TP is demonstrated by daily samples (n=1676) from a single reservoir, with average variability, that covers about 94% of the statewide Chl and about a third of the TP range. The Chl-TP pattern in over half of Missouri reservoirs deviates somewhat from predictions based on cross-system regression models. Nonetheless, for 97% of the study reservoirs, long-term Chl is within a factor of two above or below model predictions, and most are within ±25%. Such differences are modest when compared to the temporal variation measured in an intensively studied reservoir. |
| Effects of Catchment Development on the Trophic Status of a Deep and a Shallow Reservoir in Portugal | Nuno-Gonçalo Matias; Maria-José Boavida | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 350 - 360 | Effects of Catchment Development on the Trophic Status of a Deep and a Shallow Reservoir in Portugal Authors: Nuno-Gonalo Matiasa; Maria-Jos Boavidaa Abstract Although catchment nutrient flux regulation is considered vital for controlling eutrophication, direct measurement of runoff loads is difficult. Shallow eutrophic Divor and smaller deep mesotrophic Apartadura, with different catchment uses but almost identical lake-to-watershed area ratios, were studied. Ratios suggest both reservoirs should be oligo- to meso-trophic. Divor catchment intensive livestock farming opposes to subsistence farming in Apartadura catchment. Runoff coefficients indicated that cattle accounted for 75% of TP mass export in Divor but only about a third in Apartadura, where goats and sheep dominated. In both watersheds agriculture, including pasture, dominated TP export over woodland/brush cover. Because of the large agricultural component, people contributed <1% TP loading to Divor and 2-4% to Apartadura, reflecting population densities. Despite differences in watershed use and lake morphometry, reservoirs showed similar behaviour (summer hypolimnion anoxia, photic zone algal biomass). Transparent Apartadura was dominated by large algal particles and probably P-limited, while turbid Divor contained surplus phosphorus because of large amounts of fine suspended clay particles. The differences in mean depth, not watershed loading, apparently accounted for most of the differences in trophic state. Based on results, management actions to reduce eutrophication in the two reservoirs will differ. Divor drainage will primarily require better manure disposal and fertilizer use reduction but will probably not show trophic state improvement. Apartadura drainage will require diffuse-source P-control (constructed wetlands, riparian buffers) and it should respond by regaining an oxygenated hypolimnion. Stakeholder voluntary cooperation as well as modifying people's perceptions regarding water resources will be needed to comply with the legally binding EU Water Directives. Keywords: reservoir; catchment; in-lake processes; phosphorus; trophic state; land use View Full Text ArticleSubscribe Affiliation: a Departamento de Biologia Animal, Centro de Biologia Ambiental, Lisboa, Portugal DOI: 10.1080/07438140509354440 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 September 2005 Formats available: PDF (English) | Although catchment nutrient flux regulation is considered vital for controlling eutrophication, direct measurement of runoff loads is difficult. Shallow eutrophic Divor and smaller deep mesotrophic Apartadura, with different catchment uses but almost identical lake-to-watershed area ratios, were studied. Ratios suggest both reservoirs should be oligo- to meso-trophic. Divor catchment intensive livestock farming opposes to subsistence farming in Apartadura catchment. Runoff coefficients indicated that cattle accounted for 75% of TP mass export in Divor but only about a third in Apartadura, where goats and sheep dominated. In both watersheds agriculture, including pasture, dominated TP export over woodland/brush cover. Because of the large agricultural component, people contributed <1% TP loading to Divor and 2-4% to Apartadura, reflecting population densities. Despite differences in watershed use and lake morphometry, reservoirs showed similar behaviour (summer hypolimnion anoxia, photic zone algal biomass). Transparent Apartadura was dominated by large algal particles and probably P-limited, while turbid Divor contained surplus phosphorus because of large amounts of fine suspended clay particles. The differences in mean depth, not watershed loading, apparently accounted for most of the differences in trophic state. Based on results, management actions to reduce eutrophication in the two reservoirs will differ. Divor drainage will primarily require better manure disposal and fertilizer use reduction but will probably not show trophic state improvement. Apartadura drainage will require diffuse-source P-control (constructed wetlands, riparian buffers) and it should respond by regaining an oxygenated hypolimnion. Stakeholder voluntary cooperation as well as modifying people's perceptions regarding water resources will be needed to comply with the legally binding EU Water Directives. |
| Characterization of Boulder Basin, Lake Mead, Nevada-Arizona, USA – Based on Analysis of 34 Limnological Parameters | James F. LaBounty; Noel M. Burns | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 277 - 307 | Characterization of Boulder Basin, Lake Mead, Nevada-Arizona, USA - Based on Analysis of 34 Limnological Parameters Authors: James F. LaBountya; Noel M. Burnsb Abstract Lake Mead is a 66,000 ha-deep subtropical reservoir located on the Colorado River, Nevada-Arizona. This largest U.S. reservoir by volume is limnologically complex with four inflows, three basins, plus variable seasonal and annual operational patterns. This investigation is about the most downstream basin, Boulder Basin. Thirty-four measured parameters are used to describe limnological conditions of Boulder Basin, including Las Vegas Bay, from 1990-2004. Some assessments use data sets from May 2000 to April 2004; other assessments use more extensive data sets spanning up to 14 years of records. Selected parameters, trends, basic and reservoir-specific processes, and limnologically important relationships are illustrated and discussed. Boulder Basin is well stratified and ecologically complex due to the existence of two interflows. A super- to mesotrophic gradient exists from the nutrient rich inner basin, which has inflow from an urban tributary, to the middle and outer basins, which become progressively less productive. Secchi depth increases, chlorophyll (Chl a), plankton abundance, conductivity and total organic carbon (TOC) decrease going from the inner to outer basins. Lake Mead is strongly phosphorus (P)-limited and subject to a variety of algae blooms that depend on the presence and amounts of phosphorus. Due to ecological complexity, managing this resource is difficult and fraught with risk when conditions change. Along with the changing hydrologic conditions of the watershed that heavily influence Lake Mead, man-made products and toxin-producing algae are being introduced that need monitoring and management. Keywords: reservoir ecology; applied limnology; Lake Mead; phosphorus; nitrogen; Secchi depth; trophic index; data management tools View Full Text ArticleSubscribe Affiliations: a Southern Nevada Water Authority, Las Vegas, NV b Lakes Consulting, Devonport, New Zealand DOI: 10.1080/07438140509354435 Published in: Lake and Reservoir Management, Volume 21, Issue 3 September 2005 , pages 277 - 307 Publication Frequency: 4 issues per year First Published on: 01 September 2005 Formats available: PDF (English) | Lake Mead is a 66,000 ha-deep subtropical reservoir located on the Colorado River, Nevada-Arizona. This largest U.S. reservoir by volume is limnologically complex with four inflows, three basins, plus variable seasonal and annual operational patterns. This investigation is about the most downstream basin, Boulder Basin. Thirty-four measured parameters are used to describe limnological conditions of Boulder Basin, including Las Vegas Bay, from 1990-2004. Some assessments use data sets from May 2000 to April 2004; other assessments use more extensive data sets spanning up to 14 years of records. Selected parameters, trends, basic and reservoir-specific processes, and limnologically important relationships are illustrated and discussed. Boulder Basin is well stratified and ecologically complex due to the existence of two interflows. A super- to mesotrophic gradient exists from the nutrient rich inner basin, which has inflow from an urban tributary, to the middle and outer basins, which become progressively less productive. Secchi depth increases, chlorophyll (Chl a), plankton abundance, conductivity and total organic carbon (TOC) decrease going from the inner to outer basins. Lake Mead is strongly phosphorus (P)-limited and subject to a variety of algae blooms that depend on the presence and amounts of phosphorus. Due to ecological complexity, managing this resource is difficult and fraught with risk when conditions change. Along with the changing hydrologic conditions of the watershed that heavily influence Lake Mead, man-made products and toxin-producing algae are being introduced that need monitoring and management. |
| Interaction of Nutrients and Turbidity in the Control of Phytoplankton in a Large Western Canadian Lake Prior to Major Watershed Impoundments | T. G. Northcote; F. R. Pick; D. B. Fillion; S. P. Salter | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 261 - 276 | Interaction of Nutrients and Turbidity in the Control of Phytoplankton in a Large Western Canadian Lake Prior to Major Watershed Impoundments Authors: T. G. Northcotea; F. R. Pickb; D. B. Fillion; S. P. Salter Abstract Kootenay Lake is a large (over 392 km2) fjord-type lake, part of the upper Columbia River Basin, which has undergone significant limnological changes due to a range of human activities over the past half century. We analyzed the limnological conditions of the lake during the mid 1960s, prior to major dam construction on its main tributaries. At that time, large volumes (25.4 km3 yr-1) of highly turbid (up to 180 JTU) but anthropogenically phosphate-enriched water entered the south end via the Kootenay River. This interacted with smaller volumes of less turbid and much lower nutrient waters entering from the Duncan River in the north and lateral lake drainages (15.6 and 9.8 km3 yr-1 respectively) to produce complex spatial and temporal differences in physical and chemical features (temperature, light penetration, ionic composition, pH, dissolved oxygen and nutrients) as well as in phytoplankton biomass, productivity and taxonomic composition. In the southern part of the lake, phytoplankton biomass, cell density and 14C uptake rates were severely depressed during late spring and summer by light limitation from incoming silt turbidity, in spite of high phosphate concentrations. In contrast, phytoplankton stock and production was elevated in the middle to northern parts where transparency was high. Experimental algal bioassays using filtered lake waters demonstrated that through this period nutrient (primarily phosphorus) limitation occurred in the northern but not in the southern parts of Kootenay Lake. Watershed impoundments during the 1970s homogenized and simplified this ecosystem. On-going efforts to rebuild fisheries through restoration of the pre-dam nutrient loading may not return Kootenay Lake to the spatial and temporal complexity that once existed. Keywords: watershed pre-dam conditions; phytoplankton biomass; primary productivity; light limitation; nutrient limitation; algal bioassays; mountain lake; Kootenay Lake View Full Text ArticleSubscribe Affiliations: a Dept. of Zoology, University of British Columbia, Vancouver, BC, Canada b Dept. of Biology, University of Ottawa, Ottawa, ON, Canada DOI: 10.1080/07438140509354434 Published in: Lake and Reservoir Management, Volume 21, Issue 3 September 2005 , pages 261 - 276 Publication Frequency: 4 issues per year First Published on: 01 September 2005 Formats available: PDF (English) | Kootenay Lake is a large (over 392 km2) fjord-type lake, part of the upper Columbia River Basin, which has undergone significant limnological changes due to a range of human activities over the past half century. We analyzed the limnological conditions of the lake during the mid 1960s, prior to major dam construction on its main tributaries. At that time, large volumes (25.4 km3 yr-1) of highly turbid (up to 180 JTU) but anthropogenically phosphate-enriched water entered the south end via the Kootenay River. This interacted with smaller volumes of less turbid and much lower nutrient waters entering from the Duncan River in the north and lateral lake drainages (15.6 and 9.8 km3 yr-1 respectively) to produce complex spatial and temporal differences in physical and chemical features (temperature, light penetration, ionic composition, pH, dissolved oxygen and nutrients) as well as in phytoplankton biomass, productivity and taxonomic composition. In the southern part of the lake, phytoplankton biomass, cell density and 14C uptake rates were severely depressed during late spring and summer by light limitation from incoming silt turbidity, in spite of high phosphate concentrations. In contrast, phytoplankton stock and production was elevated in the middle to northern parts where transparency was high. Experimental algal bioassays using filtered lake waters demonstrated that through this period nutrient (primarily phosphorus) limitation occurred in the northern but not in the southern parts of Kootenay Lake. Watershed impoundments during the 1970s homogenized and simplified this ecosystem. On-going efforts to rebuild fisheries through restoration of the pre-dam nutrient loading may not return Kootenay Lake to the spatial and temporal complexity that once existed. |
| A Case History: Effects of Mixing Regime on Nutrient Dynamics and Community Structure in Third Sister Lake, Michigan During Late Winter and Early Spring 2003 | K. E. Judd; H. E. Adams; N. S. Bosch; J. M. Kostrzewski; C. E. Scott; B. M. Schultz; D. H. Wang; G. W. Kling | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 316 - 329 | A Case History: Effects of Mixing Regime on Nutrient Dynamics and Community Structure in Third Sister Lake, Michigan During Late Winter and Early Spring 2003 Authors: K. E. Judda; H. E. Adamsa; N. S. Boschb; J. M. Kostrzewskia; C. E. Scotta; B. M. Schultza; D. H. Wanga; G. W. Klinga Abstract We studied the winter to spring transition in Third Sister Lake (TSL), a small glacial lake in southeastern Michigan, to determine the effect of mixing regime on nutrient dynamics and community structure in an urban temperate lake. After ice-off, the oxycline was mixed downward from 3 to 6 m depth, resulting in addition of 5 mg m-2 P-SRP, 857 mg m-2 N-NH4+, and 400 mg m-2 N-NO3- to the epilimnion, but trapping 299 mg m-2 P-SRP, 7877 mg m-2 N-NH4+ and 36 mg m-2 N-NO3- in the bottom waters. Nutrients supplied by snow melt runoff (138 mg m-2 P-SRP, 430 mg m-2 N-NH4+, 596 mg m-2 N-NO3-) were an order of magnitude greater than rain event loads (0.13 mg m-2 P-SRP, 0.17 mg m-2 N-NH4+, and 1.05 mg m-2 N-NO3-) during the transition time from ice cover to open water. Reduced spring mixing did not have a large impact on N:P molar ratios, because external N:P ratios were low (7.5) compensating for reduced supply of P from the bottom waters. Bacterial production was greater in the hypolimnion than in the epilimnion, and mesocosm experiments showed that bacteria were P limited in the epilimnion but not in the hypolimnion. Total algal and zooplankton densities increased after ice-out, while Daphnia and Bosmina densities decreased. Increases in zooplankton grazing rates after ice-off were most dramatic in small-bodied zooplankton. Sediment core analysis showed that Asterionella relative abundance continues to increase, suggesting that the lake has become more brackish and oligotrophic. Our findings suggest that TSL has undergone a transition from dimictic to meromictic conditions, and that continued salt inputs have altered the structure and function of this ecosystem. Keywords: meromixis; nutrient dynamics; N:P ratios; productivity; road salt inputs; sediment core; snow melt; spring turnover View Full Text ArticleSubscribe Affiliations: a Dept. of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI b School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI DOI: 10.1080/07438140509354437 Published in: Lake and Reservoir Management, Volume 21, Issue 3 September 2005 , pages 316 - 329 Publication Frequency: 4 issues per year First Published on: 01 September 2005 Formats available: PDF (English) | We studied the winter to spring transition in Third Sister Lake (TSL), a small glacial lake in southeastern Michigan, to determine the effect of mixing regime on nutrient dynamics and community structure in an urban temperate lake. After ice-off, the oxycline was mixed downward from 3 to 6 m depth, resulting in addition of 5 mg m-2 P-SRP, 857 mg m-2 N-NH4+, and 400 mg m-2 N-NO3- to the epilimnion, but trapping 299 mg m-2 P-SRP, 7877 mg m-2 N-NH4+ and 36 mg m-2 N-NO3- in the bottom waters. Nutrients supplied by snow melt runoff (138 mg m-2 P-SRP, 430 mg m-2 N-NH4+, 596 mg m-2 N-NO3-) were an order of magnitude greater than rain event loads (0.13 mg m-2 P-SRP, 0.17 mg m-2 N-NH4+, and 1.05 mg m-2 N-NO3-) during the transition time from ice cover to open water. Reduced spring mixing did not have a large impact on N:P molar ratios, because external N:P ratios were low (7.5) compensating for reduced supply of P from the bottom waters. Bacterial production was greater in the hypolimnion than in the epilimnion, and mesocosm experiments showed that bacteria were P limited in the epilimnion but not in the hypolimnion. Total algal and zooplankton densities increased after ice-out, while Daphnia and Bosmina densities decreased. Increases in zooplankton grazing rates after ice-off were most dramatic in small-bodied zooplankton. Sediment core analysis showed that Asterionella relative abundance continues to increase, suggesting that the lake has become more brackish and oligotrophic. Our findings suggest that TSL has undergone a transition from dimictic to meromictic conditions, and that continued salt inputs have altered the structure and function of this ecosystem. |
| Factors Related to Angler Catch of Trophy Largemouth Bass in Texas Reservoirs | Randall A. Myers; Micheal S. Allen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 3 | 2005 | 309 - 315 | Factors Related to Angler Catch of Trophy Largemouth Bass in Texas Reservoirs Authors: Randall A. Myersa; Micheal S. Allenb Abstract We used angler catch reports of largemouth bass Micropterus salmoides from Texas Parks and Wildlife Department angler recognition programs to determine if catch occurrence of trophy fish (≥5.9 kg) was greater in reservoirs stocked with fingerling Florida largemouth bass M. s. floridanus (FLMB) than in non-stocked reservoirs. We also compared trophy fish catch occurrence between reservoirs having the standard 356-mm minimum length harvest limit to reservoirs having a more restrictive length limit, and evaluated the relation of catch occurrence to reservoir age, surface area, shoreline development index (SDI), latitude, longitude, FLMB stocking frequency and density. Catch occurrence of trophy fish was significantly greater in FLMB-stocked reservoirs (29%) than in non-stocked reservoirs (4%). Probability of trophy largemouth bass catch occurrence in FLMB-stocked reservoirs increased with reservoir SDI, decreased with reservoir age, and was greater for reservoirs managed with special harvest regulations (high minimum length, protective slot, and no-harvest restrictions) than for reservoirs managed with the statewide standard minimum size. Our study indicated that introduction of FLMB into Texas reservoirs yielded greater trophy largemouth bass potential and suggested that differences in trophy potential among FLMB-stocked reservoirs are likely more a function of differing reservoir habitat than differences in FLMB stocking frequency and density. Keywords: trophy; largemouth bass; Texas; stocking; reservoir View Full Text ArticleSubscribe Affiliations: a Texas Parks and Wildlife Department, San Antonio, TX b Department of Fisheries and Aquatic Sciences, The University of Florida, Gainesville, FL DOI: 10.1080/07438140509354436 Published in: Lake and Reservoir Management, Volume 21, Issue 3 September 2005 , pages 309 - 315 Publication Frequency: 4 issues per year First Published on: 01 September 2005 Formats available: PDF (English) | We used angler catch reports of largemouth bass Micropterus salmoides from Texas Parks and Wildlife Department angler recognition programs to determine if catch occurrence of trophy fish (≥5.9 kg) was greater in reservoirs stocked with fingerling Florida largemouth bass M. s. floridanus (FLMB) than in non-stocked reservoirs. We also compared trophy fish catch occurrence between reservoirs having the standard 356-mm minimum length harvest limit to reservoirs having a more restrictive length limit, and evaluated the relation of catch occurrence to reservoir age, surface area, shoreline development index (SDI), latitude, longitude, FLMB stocking frequency and density. Catch occurrence of trophy fish was significantly greater in FLMB-stocked reservoirs (29%) than in non-stocked reservoirs (4%). Probability of trophy largemouth bass catch occurrence in FLMB-stocked reservoirs increased with reservoir SDI, decreased with reservoir age, and was greater for reservoirs managed with special harvest regulations (high minimum length, protective slot, and no-harvest restrictions) than for reservoirs managed with the statewide standard minimum size. Our study indicated that introduction of FLMB into Texas reservoirs yielded greater trophy largemouth bass potential and suggested that differences in trophy potential among FLMB-stocked reservoirs are likely more a function of differing reservoir habitat than differences in FLMB stocking frequency and density. |
| Soft Sciences and the Hard Reality of Lake Management | Kent Thornton; Christina Laurin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 203 - 208 | Soft Sciences and the Hard Reality of Lake Management Authors: Kent Thorntona; Christina Laurina Abstract Few would question that lake management requires multiple disciplines, such as fisheries biologists, limnologists, engineers, and hydrologists. Yet, watershed and lake management is fundamentally social in nature. Socioeconomic disciplines are essential if water and watershed research is to be policy and management relevant. Understanding the mental models not only of land owners and lake managers, but also the community and general public is critical if watershed and lake management practices are to be implemented and sustained. Where the mental models do not reflect factual information, social marketing approaches can be used to change both the fallacious mental model and the underlying behavior. The hard reality is that lake management practices can not be sustained without insight from the “soft sciences.†Keywords: interdisciplinary; mental model; social marketing; socioeconomic View Full Text ArticleSubscribe Affiliation: a FTN Associates, Ltd., Little Rock, AR DOI: 10.1080/07438140509354429 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Few would question that lake management requires multiple disciplines, such as fisheries biologists, limnologists, engineers, and hydrologists. Yet, watershed and lake management is fundamentally social in nature. Socioeconomic disciplines are essential if water and watershed research is to be policy and management relevant. Understanding the mental models not only of land owners and lake managers, but also the community and general public is critical if watershed and lake management practices are to be implemented and sustained. Where the mental models do not reflect factual information, social marketing approaches can be used to change both the fallacious mental model and the underlying behavior. The hard reality is that lake management practices can not be sustained without insight from the “soft sciences.†|
| Internal Phosphorus Loading in Shallow Lakes: Importance and Control | Eugene B. Welch; G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 209 - 217 | Internal Phosphorus Loading in Shallow Lakes: Importance and Control Authors: Eugene B. Welcha; G. Dennis Cookeb Abstract Decreasing the algal biomass and increasing transparency in shallow, unstratified lakes is usually more difficult than for deep, stratified lakes. Eutrophic unstratified lakes (or shallow, stratified lakes susceptible to metalimnion erosion) have typically responded slowly to reduced external nutrient loading, usually because of longevity of internal loading. That is because sediment-released nutrients (especially phosphorus) readily enter the trophogenic zone of shallow lakes during the growing season and result in high lake concentrations. In stratified lakes, metalimnia may serve as barriers to phosphorus transport into the trophogenic zone. Although the whole water column in shallow lakes is usually aerobic, several mechanisms can combine to produce relatively high sediment phosphorus release rates in these lakes. These include: 1) wind resuspension and bioturbation, combined with high pH or low Fe/P ratio that maintains high P solubility, 2) periodic anoxia and reducing conditions promoted by calm, warm weather, and 3) macro-phyte senescence. Attempts to reduce algal biomass by controlling internal phosphorus loading have often been effective. Keywords: phosphorus; internal loading; control; shallow lakes View Full Text ArticleSubscribe Affiliations: a Department of Civil Engineering, University of Washington, Seattle, WA b Department of Biological Sciences, Water Resources Research Institute, Kent State University, Kent, OH DOI: 10.1080/07438140509354430 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 209 - 217 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Decreasing the algal biomass and increasing transparency in shallow, unstratified lakes is usually more difficult than for deep, stratified lakes. Eutrophic unstratified lakes (or shallow, stratified lakes susceptible to metalimnion erosion) have typically responded slowly to reduced external nutrient loading, usually because of longevity of internal loading. That is because sediment-released nutrients (especially phosphorus) readily enter the trophogenic zone of shallow lakes during the growing season and result in high lake concentrations. In stratified lakes, metalimnia may serve as barriers to phosphorus transport into the trophogenic zone. Although the whole water column in shallow lakes is usually aerobic, several mechanisms can combine to produce relatively high sediment phosphorus release rates in these lakes. These include: 1) wind resuspension and bioturbation, combined with high pH or low Fe/P ratio that maintains high P solubility, 2) periodic anoxia and reducing conditions promoted by calm, warm weather, and 3) macro-phyte senescence. Attempts to reduce algal biomass by controlling internal phosphorus loading have often been effective. |
| Applicability of Littoral Food-web Biomanipulation for Lake Management Purposes: Snails, Macrophytes, and Water Transparency in Northeast Ohio Shallow Lakes | Paola Lombardo | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 186 - 202 | Applicability of Littoral Food-web Biomanipulation for Lake Management Purposes: Snails, Macrophytes, and Water Transparency in Northeast Ohio Shallow Lakes Author: Paola Lombardoa Abstract Seven shallow-to-intermediate-depth, meso-eutrophic lakes in northeast Ohio were surveyed July-August 1998 to evaluate a macrophyte-based littoral food-web (and its possible manipulation) role in increasing or maintaining water transparency. Macrophyte and periphyton growth were determined from pre-weighed C. demersum sprigs and biomass developed on glass tiles, respectively; littoral snail densities were estimated from assemblages in large-mesh cages at 1-m depth. Other variables were monitored weekly in situ. Lakes were generally phosphorus (P)-limited, but differed significantly in perceived state (turbid, stable or unstable clear-water), water transparency (SD), total phosphorus (TP) and chlorophyll a concentration (chla), vegetation cover (VC), snail density, sprig growth and periphyton biomass. The most richly vegetated lake was also the most stable (seasonally and long-term) clear-water lake, but midsummer SD was more strongly correlated with watershed:lake surface area. C. demersum growth was negatively correlated with periphyton biomass; meristem production was lower in turbid lakes, but was influenced by TP. Snail abundance tended to follow food (periphyton) and substrate (VC) availability, but was lower in crayfish-present lakes. Correlations between lake-describing variables were nonlinear with frequent outliers. When integrated with information from the literature, the results suggest that littoral food-web biomanipulation may be employed as a management technique in some cases. More often, macrophytes and the macrophyte-driven, snail-mediated clear-water stable state may (re)establish naturally in suitable lakes after conditions are brought above a “threshold†for plant growth. Frequent exceptions in observed patterns in this study and elsewhere suggest that applicability of littoral food-web biomanipulation should be evaluated on a case-by-case basis. Keywords: littoral food webs; macrophytes; water transparency; gastropods; periphyton; shallow lakes; lake management; alternate stable states View Full Text ArticleSubscribe Affiliation: a Department of Genetics and Molecular Biology, La Sapienza State University of Rome, Rome, Italy DOI: 10.1080/07438140509354428 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 186 - 202 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Seven shallow-to-intermediate-depth, meso-eutrophic lakes in northeast Ohio were surveyed July-August 1998 to evaluate a macrophyte-based littoral food-web (and its possible manipulation) role in increasing or maintaining water transparency. Macrophyte and periphyton growth were determined from pre-weighed C. demersum sprigs and biomass developed on glass tiles, respectively; littoral snail densities were estimated from assemblages in large-mesh cages at 1-m depth. Other variables were monitored weekly in situ. Lakes were generally phosphorus (P)-limited, but differed significantly in perceived state (turbid, stable or unstable clear-water), water transparency (SD), total phosphorus (TP) and chlorophyll a concentration (chla), vegetation cover (VC), snail density, sprig growth and periphyton biomass. The most richly vegetated lake was also the most stable (seasonally and long-term) clear-water lake, but midsummer SD was more strongly correlated with watershed:lake surface area. C. demersum growth was negatively correlated with periphyton biomass; meristem production was lower in turbid lakes, but was influenced by TP. Snail abundance tended to follow food (periphyton) and substrate (VC) availability, but was lower in crayfish-present lakes. Correlations between lake-describing variables were nonlinear with frequent outliers. When integrated with information from the literature, the results suggest that littoral food-web biomanipulation may be employed as a management technique in some cases. More often, macrophytes and the macrophyte-driven, snail-mediated clear-water stable state may (re)establish naturally in suitable lakes after conditions are brought above a “threshold†for plant growth. Frequent exceptions in observed patterns in this study and elsewhere suggest that applicability of littoral food-web biomanipulation should be evaluated on a case-by-case basis. |
| Alum:Redox-Sensitive Phosphorus Ratio Considerations and Uncertainties in the Estimation of Alum Dosage to Control Sediment Phosphorus | William F. James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 159 - 164 | Alum:Redox-Sensitive Phosphorus Ratio Considerations and Uncertainties in the Estimation of Alum Dosage to Control Sediment Phosphorus Author: William F. Jamesa Abstract Alum dosage requirements to immobilize loosely-bound and iron-bound sediment phosphorus (P) fractions (i.e., redox-sensitive P fractions) in the surface sediments of eutrophic, Squaw Lake, Wisconsin, were determined using alum assay procedures developed by Rydin and Welch (1999). Since the lake exhibits a low buffering capacity (alkalinity = 25 mg Ca L-1), an alkalinity-based calculation could not be used to estimate alum dosage. Redox-sensitive sediment P fractions of surficial sediments, which represented 44% of the inorganic sediment P, were depleted by greater than 90% at an alum (as Al):redox-sensitive P binding ratio of ~ 100:1. Our results suggest that a higher dosage of alum, based on a higher alum:redox-sensitive P binding ratio requirement, is necessary to achieve effective control of sediment P in this lake. However, uncertainties still exist in the calculation of an alum dosage based on redox-sensitive sediment P concentration. More research is needed to validate optimal alum:redox-sensitive P binding ratios for use in sediment P-based alum dosage calculations. Criteria for estimating the layer of profundal sediment (i.e., the volume of redox-sensitive sediment P or the active layer of sediment contributing to diffusive P flux) to treat is also needed in order to estimate a cost-effective alum dosage for reducing internal P loading. Keywords: alum; internal P loading; phosphorus; sediment; soft-water lake View Full Text ArticleSubscribe Affiliation: a U.S. Army Engineer Research and Development Center, Eau Galle Aquatic Ecology Laboratory, Spring Valley, WI DOI: 10.1080/07438140509354425 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 159 - 164 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Alum dosage requirements to immobilize loosely-bound and iron-bound sediment phosphorus (P) fractions (i.e., redox-sensitive P fractions) in the surface sediments of eutrophic, Squaw Lake, Wisconsin, were determined using alum assay procedures developed by Rydin and Welch (1999). Since the lake exhibits a low buffering capacity (alkalinity = 25 mg Ca L-1), an alkalinity-based calculation could not be used to estimate alum dosage. Redox-sensitive sediment P fractions of surficial sediments, which represented 44% of the inorganic sediment P, were depleted by greater than 90% at an alum (as Al):redox-sensitive P binding ratio of ~ 100:1. Our results suggest that a higher dosage of alum, based on a higher alum:redox-sensitive P binding ratio requirement, is necessary to achieve effective control of sediment P in this lake. However, uncertainties still exist in the calculation of an alum dosage based on redox-sensitive sediment P concentration. More research is needed to validate optimal alum:redox-sensitive P binding ratios for use in sediment P-based alum dosage calculations. Criteria for estimating the layer of profundal sediment (i.e., the volume of redox-sensitive sediment P or the active layer of sediment contributing to diffusive P flux) to treat is also needed in order to estimate a cost-effective alum dosage for reducing internal P loading. |
| Biologically Labile and Refractory Phosphorus Loads from the Agriculturally-Managed Upper Eau Galle River Watershed, Wisconsin | William F. James; John W. Barko | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 165 - 173 | Biologically Labile and Refractory Phosphorus Loads from the Agriculturally-Managed Upper Eau Galle River Watershed, Wisconsin Authors: William F. Jamesa; John W. Barkoa Abstract Fractionation techniques were used to quantify various biologically labile (i.e., directly available for biological uptake or subject to recycling pathways) and refractory (i.e., biologically unavailable and subject to burial) particulate and soluble phosphorus (P) forms along the longitudinal axis of the agriculturally-managed Upper Eau Galle River watershed in west-central Wisconsin. P loading increased as a function of increasing distance from the river's headwaters. However, areal P export rates were similar longitudinally, indicating a relatively homogeneous land-use mosaic throughout the watershed. P loads were composed of predominantly biologically labile constituents (i.e., 79%), with soluble P forms (i.e., soluble reactive and unreactive P) accounting for 49% and labile particulate P forms (i.e., loosely-bound PP, iron-bound PP, and labile organic/polyphosphate PP) accounting for 30% of the P load. Soluble P forms are either directly available for biological uptake or can be converted to available forms through enzymatic (i.e., alkaline phosphatase) reactions. Deposition and retention of loosely-bound and iron-bound PP in the receiving impoundment, Eau Galle Reservoir, can become an important source of internal P loading via eH and pH chemical reactions. Suspended solids loads also exhibited a high equilibrium P concentration (i.e., EPC > 0.10 mg L-1) that was similar to flow-weighted soluble reactive P concentrations in the river, suggesting equilibrium control of soluble P as loads entered the reservoir. The high EPC and a linear adsorption coefficient approaching 1000 L kg-1 indicated that binding sites of eroded soils in the runoff were enriched with P due to soil nutrient management. Our results indicated that transformations, transport, and fate of biologically labile PP, as well as soluble P, need to be considered in load reduction management to eutrophic receiving waters. Keywords: Adsorption-desorption; biological phosphorus availability; equilibrium phosphorus concentration; labile phosphorus forms; loading; phosphorus; refractory phosphorus forms; runoff; watershed View Full Text ArticleSubscribe Affiliation: a U.S. Army Engineer Research and Development Center, Eau Galle Aquatic Ecology Laboratory, Spring Valley, WI DOI: 10.1080/07438140509354426 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 165 - 173 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Fractionation techniques were used to quantify various biologically labile (i.e., directly available for biological uptake or subject to recycling pathways) and refractory (i.e., biologically unavailable and subject to burial) particulate and soluble phosphorus (P) forms along the longitudinal axis of the agriculturally-managed Upper Eau Galle River watershed in west-central Wisconsin. P loading increased as a function of increasing distance from the river's headwaters. However, areal P export rates were similar longitudinally, indicating a relatively homogeneous land-use mosaic throughout the watershed. P loads were composed of predominantly biologically labile constituents (i.e., 79%), with soluble P forms (i.e., soluble reactive and unreactive P) accounting for 49% and labile particulate P forms (i.e., loosely-bound PP, iron-bound PP, and labile organic/polyphosphate PP) accounting for 30% of the P load. Soluble P forms are either directly available for biological uptake or can be converted to available forms through enzymatic (i.e., alkaline phosphatase) reactions. Deposition and retention of loosely-bound and iron-bound PP in the receiving impoundment, Eau Galle Reservoir, can become an important source of internal P loading via eH and pH chemical reactions. Suspended solids loads also exhibited a high equilibrium P concentration (i.e., EPC > 0.10 mg L-1) that was similar to flow-weighted soluble reactive P concentrations in the river, suggesting equilibrium control of soluble P as loads entered the reservoir. The high EPC and a linear adsorption coefficient approaching 1000 L kg-1 indicated that binding sites of eroded soils in the runoff were enriched with P due to soil nutrient management. Our results indicated that transformations, transport, and fate of biologically labile PP, as well as soluble P, need to be considered in load reduction management to eutrophic receiving waters. |
| The Phosphorus Mass Balance of Lake Okeechobee, Florida: Implications for Eutrophication Management | Karl E. Havens; R. Thomas James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 139 - 148 | The Phosphorus Mass Balance of Lake Okeechobee, Florida: Implications for Eutrophication Management Authors: Karl E. Havensa; R. Thomas Jamesb Abstract A phosphorus (P) mass balance was developed for Lake Okeechobee, Florida (USA) for the period 1973 to 2002. During those 30 years, yearly P inputs averaged 499 metric tons, outputs averaged 174 metric tons, and there was a 297 metric ton ·y-1 net sink, attributed to sediment accrual. Yearly P loads were highly variable, ranging from <200 to >900 metric tons, and there was a strong positive relationship between yearly load and inflow volume (r2 = 0.73). There was no long-term trend in P loading to the lake, but the total P concentration of inflow water displayed a historic trend that was independent of inflow volume, perhaps related to P control programs in the watershed. Inflow total P increased from 150 to >200 μg·L-1 in the 1970s when land use was intensified but management programs generally were absent, but declined in the 1980s and 1990s (to ~150 μg·L-1), coincident with various P control programs. Inflow total P concentrations displayed no trend after the early 1990s, although there was considerable year-to-year variability. Lake water total P concentrations increased during the 1970s, stabilized in the 1980s and early 1990s, and increased in recent years, possibly due to sediment saturation with P. There was no significant relationship between lake water total P concentration and mean depth, contradicting earlier reports based on shorter (10 and 20-y) periods of record. The difference between annual average inflow and lake water total P declined from near 150 μg·L-1 in the 1970s to <50 μg·L-1 in recent years, and the net sedimentation coefficient declined from near 2.0 to just above zero. These trends indicate a decreasing capacity of the lake to assimilate P. Two features noted here - (1) potential of the watershed to export large amounts of P rich water in certain years, and (2) lack of P assimilative capacity of the lake - indicate that the ecosystem is at risk for continued and perhaps worsened eutrophication symptoms under current P loading conditions. Keywords: phosphorus; mass balance; shallow lakes; Lake Okeechobee View Full Text ArticleSubscribe Affiliations: a Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL b South Florida Water Management District, West Palm Beach, FL DOI: 10.1080/07438140509354423 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 139 - 148 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | A phosphorus (P) mass balance was developed for Lake Okeechobee, Florida (USA) for the period 1973 to 2002. During those 30 years, yearly P inputs averaged 499 metric tons, outputs averaged 174 metric tons, and there was a 297 metric ton ·y-1 net sink, attributed to sediment accrual. Yearly P loads were highly variable, ranging from <200 to >900 metric tons, and there was a strong positive relationship between yearly load and inflow volume (r2 = 0.73). There was no long-term trend in P loading to the lake, but the total P concentration of inflow water displayed a historic trend that was independent of inflow volume, perhaps related to P control programs in the watershed. Inflow total P increased from 150 to >200 μg·L-1 in the 1970s when land use was intensified but management programs generally were absent, but declined in the 1980s and 1990s (to ~150 μg·L-1), coincident with various P control programs. Inflow total P concentrations displayed no trend after the early 1990s, although there was considerable year-to-year variability. Lake water total P concentrations increased during the 1970s, stabilized in the 1980s and early 1990s, and increased in recent years, possibly due to sediment saturation with P. There was no significant relationship between lake water total P concentration and mean depth, contradicting earlier reports based on shorter (10 and 20-y) periods of record. The difference between annual average inflow and lake water total P declined from near 150 μg·L-1 in the 1970s to <50 μg·L-1 in recent years, and the net sedimentation coefficient declined from near 2.0 to just above zero. These trends indicate a decreasing capacity of the lake to assimilate P. Two features noted here - (1) potential of the watershed to export large amounts of P rich water in certain years, and (2) lack of P assimilative capacity of the lake - indicate that the ecosystem is at risk for continued and perhaps worsened eutrophication symptoms under current P loading conditions. |
| Toward Integration in Reservoir Management | Robert H. Kennedy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 128 - 138 | Toward Integration in Reservoir Management Author: Robert H. Kennedya Abstract Reservoirs are engineered features of hydrologic landscapes with characteristics defined by engineering design criteria. Many of these characteristics impact water quality. Reservoir management has historically been dictated by water control requirements; environment and water quality have been secondary considerations. Management approaches that address inputs of nutrients, sediment and organic material as root causes of eutrophication have been difficult to implement due to the location of reservoirs in large, complex watersheds. Costly engineering solutions that reduce symptoms of problems rather than address their cause are favored over watershed-based approaches applied to smaller natural lakes. To be successful, future management initiatives will require more integrative approaches that recognize reservoirs as integral components of watersheds and river basins. Understanding interactions between engineering practice and water quality fosters the development and implementation of effective management approaches that address environmental and water quality concerns as well as water quantity. Keywords: reservoir; water quality; reservoir management; reservoir operation View Full Text ArticleSubscribe Affiliation: a European Research Office, US Army Engineer Research and Development Center, London, United Kingdom DOI: 10.1080/07438140509354422 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 128 - 138 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Reservoirs are engineered features of hydrologic landscapes with characteristics defined by engineering design criteria. Many of these characteristics impact water quality. Reservoir management has historically been dictated by water control requirements; environment and water quality have been secondary considerations. Management approaches that address inputs of nutrients, sediment and organic material as root causes of eutrophication have been difficult to implement due to the location of reservoirs in large, complex watersheds. Costly engineering solutions that reduce symptoms of problems rather than address their cause are favored over watershed-based approaches applied to smaller natural lakes. To be successful, future management initiatives will require more integrative approaches that recognize reservoirs as integral components of watersheds and river basins. Understanding interactions between engineering practice and water quality fosters the development and implementation of effective management approaches that address environmental and water quality concerns as well as water quantity. |
| Preface | Robert H. Kennedy; Spencer A. Peterson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 127 | Preface Authors: Robert H. Kennedy; Spencer A. Peterson View Full Text ArticleSubscribe DOI: 10.1080/07438140509354421 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , page 127 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | |
| Development of Regional Nutrient Criteria and Implications for States and the Regulated Community | Nancy Palmstrom | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 174 - 185 | Development of Regional Nutrient Criteria and Implications for States and the Regulated Community Author: Nancy Palmstroma Abstract Nutrient enrichment is a major threat to many of the nation's surface waters. The U.S. Environmental Protection Agency (EPA) has made development of nutrient criteria to protect the uses and functions of these waters a national priority (EPA 1998). Establishment of these nutrient criteria must take into account regional differences and waterbody characteristics. EPA has published related guidance documents for development of criteria, as well as ecoregional nutrient criteria documents for lakes and reservoirs and rivers and streams. Work is underway in states across the United States to gather data and develop regional nutrient criteria. The development of a database for EPA Region 3 to support regional nutrient criteria development is discussed, and use of the database for criteria development is demonstrated. Potential implications for states, River Basin Commissions (RBCs), tribes and wastewater dischargers are also addressed. Keywords: nutrient criteria; nutrients; water quality criteria View Full Text ArticleSubscribe Affiliation: a ENSR International, Piscataway, NJ DOI: 10.1080/07438140509354427 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 174 - 185 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Nutrient enrichment is a major threat to many of the nation's surface waters. The U.S. Environmental Protection Agency (EPA) has made development of nutrient criteria to protect the uses and functions of these waters a national priority (EPA 1998). Establishment of these nutrient criteria must take into account regional differences and waterbody characteristics. EPA has published related guidance documents for development of criteria, as well as ecoregional nutrient criteria documents for lakes and reservoirs and rivers and streams. Work is underway in states across the United States to gather data and develop regional nutrient criteria. The development of a database for EPA Region 3 to support regional nutrient criteria development is discussed, and use of the database for criteria development is demonstrated. Potential implications for states, River Basin Commissions (RBCs), tribes and wastewater dischargers are also addressed. |
| Ecosystem Rehabilitation | G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 218 - 221 | Ecosystem Rehabilitation Author: G. Dennis Cookea Abstract Restoration of damaged or extirpated aquatic and terrestrial ecosystems has been proposed as one means of meeting Clean Water Act goals, and as a way to reduce further ecological deficits and economic losses. However, restoration means a return to pre-disturbance conditions and relies on historic landscapes or ecosystems as models. It is the most demanding of management paradigms and implies complete re-creation of a system equivalent to the model. Restoration represents the extreme on a continuum of management protocols and is valuable as an ideal. In most cases, it is impractical, uncalled for, or even impossible. Rehabilitation is the repair and replacement of essential ecosystem structures and functions in the context of ecoregional attainability in order to achieve specified objectives. It is analogous to medical rehabilitation and emphasizes return to an achievable resemblance of prior conditions and makes no pretense of accomplishing absolute authenticity. It is a process in which many ecologists are engaged. It excludes activities solely oriented to human centered needs, such as spraying and cleanups. Damage and loss of freshwater ecosystems are apparent. The consequences are just beginning to be understood. I urge the establishment of ecologically coherent Federal rehabilitation programs. Keywords: ecosystem rehabilitation; restoration View Full Text ArticleSubscribe Affiliation: a Department of Biological Sciences, Water Resources Research Institute, Kent State University, Kent, OH DOI: 10.1080/07438140509354431 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 218 - 221 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Restoration of damaged or extirpated aquatic and terrestrial ecosystems has been proposed as one means of meeting Clean Water Act goals, and as a way to reduce further ecological deficits and economic losses. However, restoration means a return to pre-disturbance conditions and relies on historic landscapes or ecosystems as models. It is the most demanding of management paradigms and implies complete re-creation of a system equivalent to the model. Restoration represents the extreme on a continuum of management protocols and is valuable as an ideal. In most cases, it is impractical, uncalled for, or even impossible. Rehabilitation is the repair and replacement of essential ecosystem structures and functions in the context of ecoregional attainability in order to achieve specified objectives. It is analogous to medical rehabilitation and emphasizes return to an achievable resemblance of prior conditions and makes no pretense of accomplishing absolute authenticity. It is a process in which many ecologists are engaged. It excludes activities solely oriented to human centered needs, such as spraying and cleanups. Damage and loss of freshwater ecosystems are apparent. The consequences are just beginning to be understood. I urge the establishment of ecologically coherent Federal rehabilitation programs. |
| Wind Control on Water Quality in Shallow, Hypereutrophic Upper Klamath Lake, Oregon | Jacob Kann; Eugene B. Welch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 2 | 2005 | 149 - 158 | Wind Control on Water Quality in Shallow, Hypereutrophic Upper Klamath Lake, Oregon Authors: Jacob Kanna; Eugene B. Welchbc Abstract Large blooms of cyanobacteria, primarily Aphanizomenon flos-aquae, are linked to poor water quality in Upper Klamath Lake, Oregon. High pH and high un-ionized ammonia concentrations are associated with the blooms when algae are actively growing, followed by low dissolved oxygen (DO) conditions when the blooms decline in mid- to late summer. Over a 12-year study period, algal biomass was strongly related to total phosphorus concentration (TP) and pH. Minimum water column DO was strongly related to net negative changes (i.e., declines) in algal biomass during July and August. The severity of both low DO and high ammonia was positively related to water column stability, which was dependent on wind speed. Bloom dynamics, coupled with climate, dominated year-to-year variability in water quality dynamics in Upper Klamath Lake. These data provide the empirical basis for previous research linking high mortalities of endangered sucker species with years of low wind and high water column stability. Keywords: wind mixing; water column stability; water quality; blue-green algal blooms; fish kills View Full Text ArticleSubscribe Affiliations: a Aquatic Ecosystem Sciences, LLC, Ashland, OR b Department of Civil and Environmental Engineering, University of Washington, Seattle, WA c Tetra Tech, Inc., Seattle, WA DOI: 10.1080/07438140509354424 Published in: Lake and Reservoir Management, Volume 21, Issue 2 June 2005 , pages 149 - 158 Publication Frequency: 4 issues per year First Published on: 01 June 2005 Formats available: PDF (English) | Large blooms of cyanobacteria, primarily Aphanizomenon flos-aquae, are linked to poor water quality in Upper Klamath Lake, Oregon. High pH and high un-ionized ammonia concentrations are associated with the blooms when algae are actively growing, followed by low dissolved oxygen (DO) conditions when the blooms decline in mid- to late summer. Over a 12-year study period, algal biomass was strongly related to total phosphorus concentration (TP) and pH. Minimum water column DO was strongly related to net negative changes (i.e., declines) in algal biomass during July and August. The severity of both low DO and high ammonia was positively related to water column stability, which was dependent on wind speed. Bloom dynamics, coupled with climate, dominated year-to-year variability in water quality dynamics in Upper Klamath Lake. These data provide the empirical basis for previous research linking high mortalities of endangered sucker species with years of low wind and high water column stability. |
| Influences of Lake Level Changes on Reservoir Water Clarity in Allatoona Lake, Georgia | Joseph M. Dirnberger; Jason Weinberger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 24 - 29 | Influences of Lake Level Changes on Reservoir Water Clarity in Allatoona Lake, Georgia Authors: Joseph M. Dirnbergera; Jason Weinbergera Abstract In Allatoona Lake (Georgia USA), secchi transparency (measured every 2 to 4 weeks during a Phase I U.S. EPA Clean Lakes Study) was typically 5- to 8- fold greater in summer than late autumn and winter. The intensity of storms increased in late autumn and winter resulting in high sediment loads from the watershed, but lake level was also drawn down, confounding the influence of external sediment load with that of resuspended lake sediments. For 4 of the 5 years studied, decreases in water clarity were more closely synchronized with lowering of lake level than with storms. Continuous automated sampling of turbidity and other water quality parameters at 15-minute intervals allowed us to assess whether turbidity increases were derived from erosion of the exposed shoreline (i.e., by rain and runoff), or wave-driven resuspension. Regular increases in turbidity and decreases in pH occurred each weekend during the summer, suggesting increased mixing by boat traffic. Increases in turbidity on weekends and after rain events were greater after initiation of drawdown and were particularly strong when lake surface elevation approached that of the summer metalimnion depth. It appears that sediment focused (deposited) in deeper areas during the spring and summer is resuspended by wave action as lake levels drop in autumn. Keywords: water clarity; lake level; reservoir; sediment focusing; wind; turbidity View Full Text ArticleSubscribe Affiliation: a Department of Biological and Physical Sciences, Kennesaw State University, Kennesaw, GA DOI: 10.1080/07438140509354409 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | In Allatoona Lake (Georgia USA), secchi transparency (measured every 2 to 4 weeks during a Phase I U.S. EPA Clean Lakes Study) was typically 5- to 8- fold greater in summer than late autumn and winter. The intensity of storms increased in late autumn and winter resulting in high sediment loads from the watershed, but lake level was also drawn down, confounding the influence of external sediment load with that of resuspended lake sediments. For 4 of the 5 years studied, decreases in water clarity were more closely synchronized with lowering of lake level than with storms. Continuous automated sampling of turbidity and other water quality parameters at 15-minute intervals allowed us to assess whether turbidity increases were derived from erosion of the exposed shoreline (i.e., by rain and runoff), or wave-driven resuspension. Regular increases in turbidity and decreases in pH occurred each weekend during the summer, suggesting increased mixing by boat traffic. Increases in turbidity on weekends and after rain events were greater after initiation of drawdown and were particularly strong when lake surface elevation approached that of the summer metalimnion depth. It appears that sediment focused (deposited) in deeper areas during the spring and summer is resuspended by wave action as lake levels drop in autumn. |
| Evaluation of the Potential Adverse Effects of Lake Inflow Treatment with Alum | Keith M. Pilgrim; Patrick L. Brezonik | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 77 - 87 | Evaluation of the Potential Adverse Effects of Lake Inflow Treatment with Alum Authors: Keith M. Pilgrima; Patrick L. Brezonika Abstract Laboratory and field investigations at Fish Lake in Eagan, MN, and Tanners Lake in Oakdale, MN, were conducted to evaluate the potential adverse effects of using alum to treat lake inflows. Detention ponds are used at both sites to promote settling of alum floc before discharge to the lake. Tests in a 1.5 m column designed to estimate settling in detention ponds showed nearly complete Al settling by 6 h. Final residual Al concentrations were affected only slightly by dose. Average concentrations of total Al entering Fish Lake were 346 and 458 μg Al L-1 at doses of 1 and 8 mg Al L-1, and average in-lake concentrations were 70 and 152 μg L-1. Aluminum settled in Fish Lake at a rate of 74 m y-1. Average Al concentrations in Tanners Lake inflow were higher, but Al concentrations in the lake were lower because of its greater size. The settling pond at Fish Lake protected benthic invertebrates in the lake, but floc accumulation during treatment at 8 mg Al L-1 eliminated nearly all invertebrates in the pond. Concentrations of Al that showed no observed mortality effects (NOECs) were assembled from literature, and a measure of unbound, positively charged Al species (Allm) was compared to the NOECs to evaluate potential aquatic toxicity from alum treatment. The potential risk of aquatic toxicity should be negligible if treated water entering the lake has a pH > 6.0. Keywords: alum treatment; aquatic toxicity; benthic invertebrates; aluminum; speciation View Full Text ArticleSubscribe Affiliation: a Water Resources Science Graduate Program and Department of Civil Engineering, University of Minnesota, Minneapolis, MN DOI: 10.1080/07438140509354408 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 77 - 87 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Laboratory and field investigations at Fish Lake in Eagan, MN, and Tanners Lake in Oakdale, MN, were conducted to evaluate the potential adverse effects of using alum to treat lake inflows. Detention ponds are used at both sites to promote settling of alum floc before discharge to the lake. Tests in a 1.5 m column designed to estimate settling in detention ponds showed nearly complete Al settling by 6 h. Final residual Al concentrations were affected only slightly by dose. Average concentrations of total Al entering Fish Lake were 346 and 458 μg Al L-1 at doses of 1 and 8 mg Al L-1, and average in-lake concentrations were 70 and 152 μg L-1. Aluminum settled in Fish Lake at a rate of 74 m y-1. Average Al concentrations in Tanners Lake inflow were higher, but Al concentrations in the lake were lower because of its greater size. The settling pond at Fish Lake protected benthic invertebrates in the lake, but floc accumulation during treatment at 8 mg Al L-1 eliminated nearly all invertebrates in the pond. Concentrations of Al that showed no observed mortality effects (NOECs) were assembled from literature, and a measure of unbound, positively charged Al species (Allm) was compared to the NOECs to evaluate potential aquatic toxicity from alum treatment. The potential risk of aquatic toxicity should be negligible if treated water entering the lake has a pH > 6.0. |
| Treatment of Lake Inflows with Alum for Phosphorus Removal | Keith M. Pilgrim; Patrick L. Brezonik | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 1-9 | Treatment of Lake Inflows with Alum for Phosphorus Removal Authors: Keith M. Pilgrimab; Patrick L. Brezonikac Abstract Alum is being used on an experimental basis to remove phosphorus (P) from the inflows of Fish and Tanners Lakes in the Minneapolis and St. Paul metropolitan area of Minnesota. Jar test studies and experiments with settling columns demonstrated the usefulness of these methods for proper design of inflow alum treatment systems. Mixing conditions in treatment facilities at both lakes promote good floc development. The degree of alum and water mixing, defined by the velocity gradient (G, s-1) and mixing time (t, in s), or Gt, was 7,700-35,000 for Tanners Lake and the maximum potential Gt for Fish Lake was 42,000. The concentration of TP entering Fish Lake was greatly reduced at an alum dose of 8 mg Al L-1 but was largely unaffected at 1 mg Al L-1. Average annual TP removal from 1998 to 2003 with alum doses of 1.9 to 10.5 mg Al L-1 ranged from 61 to 84% at Tanners Lake. Surface TP declined rapidly with alum treatment in both lakes. Average annual Secchi disk depth (SD) for the west bay of Fish Lake improved from 1.5 m in 1998 to 2.1 m in 2000 despite a 28 cm storm event in July 2000 that led to large inflows to the lake. Treatment at Tanners Lake, which occurred during the entire year, was effective in reducing the long-term (May through September) average TP concentration in the surface of Tanners Lake from approximately 50 to just under 30 μg L-1. Alum floc, which was deposited in sediments of a settling pond prior to Fish Lake and in the lake sediments inhibited P release under anoxic conditions. Keywords: alum treatment; phosphorus removal; design View Full Text ArticleSubscribe Affiliations: a Water Resources Science Program and Department of Civil Engineering, University of Minnesota, Minneapolis, MN b Barr Engineering, Minneapolis, MN c National Science Foundation, Arlington, VA DOI: 10.1080/07438140509354407 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 1 - 9 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Alum is being used on an experimental basis to remove phosphorus (P) from the inflows of Fish and Tanners Lakes in the Minneapolis and St. Paul metropolitan area of Minnesota. Jar test studies and experiments with settling columns demonstrated the usefulness of these methods for proper design of inflow alum treatment systems. Mixing conditions in treatment facilities at both lakes promote good floc development. The degree of alum and water mixing, defined by the velocity gradient (G, s-1) and mixing time (t, in s), or Gt, was 7,700-35,000 for Tanners Lake and the maximum potential Gt for Fish Lake was 42,000. The concentration of TP entering Fish Lake was greatly reduced at an alum dose of 8 mg Al L-1 but was largely unaffected at 1 mg Al L-1. Average annual TP removal from 1998 to 2003 with alum doses of 1.9 to 10.5 mg Al L-1 ranged from 61 to 84% at Tanners Lake. Surface TP declined rapidly with alum treatment in both lakes. Average annual Secchi disk depth (SD) for the west bay of Fish Lake improved from 1.5 m in 1998 to 2.1 m in 2000 despite a 28 cm storm event in July 2000 that led to large inflows to the lake. Treatment at Tanners Lake, which occurred during the entire year, was effective in reducing the long-term (May through September) average TP concentration in the surface of Tanners Lake from approximately 50 to just under 30 μg L-1. Alum floc, which was deposited in sediments of a settling pond prior to Fish Lake and in the lake sediments inhibited P release under anoxic conditions. |
| VOC Loading from Marine Engines to a Multiple-use Lake | Prescott C. Heald; S. Geoffrey Schladow; Brant C. Allen; John E. Reuter | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 30 - 38 | VOC Loading from Marine Engines to a Multiple-use Lake Authors: Prescott C. Healda; S. Geoffrey Schladowb; Brant C. Allenc; John E. Reuterc Abstract A detailed boating use survey was conducted at a Northern California multiple-use lake, and the results were used to quantify daily MTBE and BTEX loading from recreational boating. Boat owner interviews and whole-lake activity surveys were conducted on 43 days between June 17 and September 20, 2000, including 38 days during the peak boating months of July and August. The dominant class of marine engines was found to be 4-stroke inboards and inboard/outboards, which constituted 60 percent of the total number of engines and consumed 69 percent of the fuel used at the lake. 2-stroke outboard engines with carburetors represented 26 percent of the engines and 14.3 percent of the fuel consumption, but were found to contribute 68 percent of MTBE and BTEX loading, while 4-stroke inboards were responsible for 4.2 percent. A sampling program was conducted in which MTBE/BTEX samples were collected on 23 days between May 22 and October 23, 2000. Results showed that MTBE appeared in 95 percent of epilimnetic samples up to a maximum concentration of 3.5 μg·l-1 while toluene was detected in 22 percent of epilimnetic samples at a maximum concentration of 0.5 μg·1-1. O-xylene was detected on one day, and benzene, ethlybenzene and m,p-xylene were not detected. The study demonstrated that MTBE is more persistent than BTEX compounds in surface water bodies, and accumulates over time with continuous inputs. Keywords: fuel; VOC; lake; MTBE; BTEX; loading View Full Text ArticleSubscribe Affiliations: a West Yost & Associates, Davis, CA b Department of Civil and Environmental Engineering, University of California, Davis, Davis, CA c Department of Environmental Science and Policy, University of California, Davis, Davis, CA DOI: 10.1080/07438140509354410 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 30 - 38 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | A detailed boating use survey was conducted at a Northern California multiple-use lake, and the results were used to quantify daily MTBE and BTEX loading from recreational boating. Boat owner interviews and whole-lake activity surveys were conducted on 43 days between June 17 and September 20, 2000, including 38 days during the peak boating months of July and August. The dominant class of marine engines was found to be 4-stroke inboards and inboard/outboards, which constituted 60 percent of the total number of engines and consumed 69 percent of the fuel used at the lake. 2-stroke outboard engines with carburetors represented 26 percent of the engines and 14.3 percent of the fuel consumption, but were found to contribute 68 percent of MTBE and BTEX loading, while 4-stroke inboards were responsible for 4.2 percent. A sampling program was conducted in which MTBE/BTEX samples were collected on 23 days between May 22 and October 23, 2000. Results showed that MTBE appeared in 95 percent of epilimnetic samples up to a maximum concentration of 3.5 μg·l-1 while toluene was detected in 22 percent of epilimnetic samples at a maximum concentration of 0.5 μg·1-1. O-xylene was detected on one day, and benzene, ethlybenzene and m,p-xylene were not detected. The study demonstrated that MTBE is more persistent than BTEX compounds in surface water bodies, and accumulates over time with continuous inputs. |
| Strategies for Managing the Lakes of the Rotorua District, New Zealand | Noel Burns; John McIntosh; Paul Scholes | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 61 - 72 | Strategies for Managing the Lakes of the Rotorua District, New Zealand Authors: Noel Burnsa; John McIntoshb; Paul Scholesb Abstract The Rotorua district in New Zealand contains 12 nationally important lakes. Environment Bay of Plenty (EBOP), which has the responsibility of managing the quality of these lakes, set a routine monitoring program for these lakes and adopted the method of Burns et al. (1999, 2000) to analyse the data and calculate a numeric Trophic Level Index (TLI) value for each. In 1994, the district community indicated a goal to maintain the present condition for most of the lakes and to improve the remainder. As a result, numeric baseline TLI values were written into the Proposed Regional Water and Land Plan as the Rotorua District lake-water quality objectives. This plan also required formation of a community action plan for the remediation of any lake that exceeded its baseline TLI, a criterion that targeted five lakes. Deterioration in the water quality of these lakes is linked to urban expansion and gradual conversion of forested land to pasture over the past 100 years. Draft action plans identifying causes of lake deterioration, together with possible means of solving the problems, have been published for four lakes. Annual reports on the state of each lake have been published since 2000. This lake management system has resulted in valuable communication between EBOP, the Rotorua District Council and the communities living around the lakes, and has been instrumental in obtaining a cooperative approach to solving the identified problems. Methods to remediate these lakes include: converting pasture back to forest; alum dosing; creating riparian strips along streambanks; developing wetlands; installing reticulated sewage systems, and; diverting wastewater inputs from a lake into nearby forests. Keywords: lake monitoring; trophic levels; baseline trophic conditions; action plans; groundwater nitrate; water quality trends; global warming; New Zealand lakes View Full Text ArticleSubscribe Affiliations: a Lakes Consulting, Devonport, New Zealand b Environment Bay of Plenty, Whakatane, New Zealand DOI: 10.1080/07438140509354413 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 61 - 72 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | The Rotorua district in New Zealand contains 12 nationally important lakes. Environment Bay of Plenty (EBOP), which has the responsibility of managing the quality of these lakes, set a routine monitoring program for these lakes and adopted the method of Burns et al. (1999, 2000) to analyse the data and calculate a numeric Trophic Level Index (TLI) value for each. In 1994, the district community indicated a goal to maintain the present condition for most of the lakes and to improve the remainder. As a result, numeric baseline TLI values were written into the Proposed Regional Water and Land Plan as the Rotorua District lake-water quality objectives. This plan also required formation of a community action plan for the remediation of any lake that exceeded its baseline TLI, a criterion that targeted five lakes. Deterioration in the water quality of these lakes is linked to urban expansion and gradual conversion of forested land to pasture over the past 100 years. Draft action plans identifying causes of lake deterioration, together with possible means of solving the problems, have been published for four lakes. Annual reports on the state of each lake have been published since 2000. This lake management system has resulted in valuable communication between EBOP, the Rotorua District Council and the communities living around the lakes, and has been instrumental in obtaining a cooperative approach to solving the identified problems. Methods to remediate these lakes include: converting pasture back to forest; alum dosing; creating riparian strips along streambanks; developing wetlands; installing reticulated sewage systems, and; diverting wastewater inputs from a lake into nearby forests. |
| Changes in Primary Production in Onondaga Lake, NY: Magnitude, Metrics, and Drivers | Steven W. Effler; Rakesh K. Gelda; Stephen E. Field; Adam J. P. Effler; Erik B. Wallenberg; David A. Matthews | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 49 - 60 | Changes in Primary Production in Onondaga Lake, NY: Magnitude, Metrics, and Drivers Authors: Steven W. Efflera; Rakesh K. Geldaa; Stephen E. Fielda; Adam J. P. Efflera; Erik B. Wallenberga; David A. Matthewsa Abstract Changes in phytoplankton primary production and common metrics and drivers of trophic state are documented and critically evaluated for a 35 year (1968-2002) period for polluted, culturally eutrophic Onondaga Lake, NY. The lake is presently the focus of an on-going rehabilitation program to abate its cultural eutrophication problems. The analysis is supported by measurements of primary production and long-term monitoring of trophic state metrics and other common limnological parameters. Measurements of primary production and community respiration were made in 1978, 2002, and portions of 2000 and 2001, utilizing dissolved oxygen-based isolated community (light/dark bottle) and non-isolated community (diel measurements) protocols. Limnological and discharge monitoring of the following metrics supported the analysis: epilimnetic total phosphorus, epilimnetic chlorophyll a (Chle), Secchi disc (SD), areal hypolimnetic oxygen deficit (AHOD), salinity (S), downward flux of particulate organic carbon (POCdf), and concentration of TP in the effluent of a wastewater treatment plant (TPMetro) that dominates loading. Direct measurements establish the areal daily average gross primary production has decreased ~ 30 to 40% since 1978. The magnitude of this decrease corresponds well with decreases observed in the surrogate metrics of primary production of POCdf (37%) and AHOD (49%). Detailed time series of POCdf and AHOD indicate the decrease occurred abruptly in the late 1980s. This decrease was primarily a result of the reduction in S that attended cessation of production by an industry, rather than a response to the 30-fold reduction in TPMetro achieved over the last 32 years. Magnitudes of Chle and SD are not presently reliable metrics of trophic state in this lake because of increases, and year-to-year variations, in top-down effects since closure of the industry. Keywords: primary production; trophic state; water quality; Onondaga Lake; eutrophication; dissolved oxygen; metabolic rates; light-dark bottles View Full Text ArticleSubscribe Affiliation: a Upstate Freshwater Institute, Syracuse, NY DOI: 10.1080/07438140509354412 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 49 - 60 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Changes in phytoplankton primary production and common metrics and drivers of trophic state are documented and critically evaluated for a 35 year (1968-2002) period for polluted, culturally eutrophic Onondaga Lake, NY. The lake is presently the focus of an on-going rehabilitation program to abate its cultural eutrophication problems. The analysis is supported by measurements of primary production and long-term monitoring of trophic state metrics and other common limnological parameters. Measurements of primary production and community respiration were made in 1978, 2002, and portions of 2000 and 2001, utilizing dissolved oxygen-based isolated community (light/dark bottle) and non-isolated community (diel measurements) protocols. Limnological and discharge monitoring of the following metrics supported the analysis: epilimnetic total phosphorus, epilimnetic chlorophyll a (Chle), Secchi disc (SD), areal hypolimnetic oxygen deficit (AHOD), salinity (S), downward flux of particulate organic carbon (POCdf), and concentration of TP in the effluent of a wastewater treatment plant (TPMetro) that dominates loading. Direct measurements establish the areal daily average gross primary production has decreased ~ 30 to 40% since 1978. The magnitude of this decrease corresponds well with decreases observed in the surrogate metrics of primary production of POCdf (37%) and AHOD (49%). Detailed time series of POCdf and AHOD indicate the decrease occurred abruptly in the late 1980s. This decrease was primarily a result of the reduction in S that attended cessation of production by an industry, rather than a response to the 30-fold reduction in TPMetro achieved over the last 32 years. Magnitudes of Chle and SD are not presently reliable metrics of trophic state in this lake because of increases, and year-to-year variations, in top-down effects since closure of the industry. |
| Temporal Coherence in Limnological Features of Two Southwestern Reservoirs | Thomas H. Chrzanowski; James P. Grover | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 39 - 48 | Temporal Coherence in Limnological Features of Two Southwestern Reservoirs Authors: Thomas H. Chrzanowskia; James P. Grovera Abstract Properties of aquatic ecosystems have recently been considered in a landscape context where lakes in a geographic area are examined to identify common and long-term behavior patterns for one or more variables. Identifying such temporally coherent features should permit generalizations about lake behavior in specific regions and therefore, predictive models based upon such information should have broad applicability within a regional landscape. We considered the temporal coherence of a number of physical, chemical, and biological features of two southwestern reservoirs that differed in age, watersheds, and trophic status to identify common landscape-level predictors of behavior. We found synchronous behavior (temporal coherence) associated with particulate nutrient dynamics (organic carbon, nitrogen and phosphate (PP)), dissolved factors that force plankton dynamics (total dissolved phosphate, reactive phosphate and reactive silicate (SRSi), and with nutrient ratios used as indices of nutrient limitation in the plankton (TDN:TDP, C:P, and N:P). Algal parameters related to biomass (chlorophyll and Simpson's diversity index) did not vary coherently but algal genus richness and bacterial abundance did. Temperature was identified as a forcing function explaining synchronous variability in all cases except SRSi, PP, C:P, N:P, bacteria, and richness. The two systems, although managed for different purposes, behaved similarly with respect to several commonly measured limnological features, most notably, those involving phosphorus. We conclude that it may be possible to use such analysis to establish reference conditions for reservoirs in a given geographic region. Keywords: reservoirs; synchrony; nutrients; models View Full Text ArticleSubscribe Affiliation: a Department of Biology, The University of Texas at Arlington, Arlington, TX DOI: 10.1080/07438140509354411 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 39 - 48 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Properties of aquatic ecosystems have recently been considered in a landscape context where lakes in a geographic area are examined to identify common and long-term behavior patterns for one or more variables. Identifying such temporally coherent features should permit generalizations about lake behavior in specific regions and therefore, predictive models based upon such information should have broad applicability within a regional landscape. We considered the temporal coherence of a number of physical, chemical, and biological features of two southwestern reservoirs that differed in age, watersheds, and trophic status to identify common landscape-level predictors of behavior. We found synchronous behavior (temporal coherence) associated with particulate nutrient dynamics (organic carbon, nitrogen and phosphate (PP)), dissolved factors that force plankton dynamics (total dissolved phosphate, reactive phosphate and reactive silicate (SRSi), and with nutrient ratios used as indices of nutrient limitation in the plankton (TDN:TDP, C:P, and N:P). Algal parameters related to biomass (chlorophyll and Simpson's diversity index) did not vary coherently but algal genus richness and bacterial abundance did. Temperature was identified as a forcing function explaining synchronous variability in all cases except SRSi, PP, C:P, N:P, bacteria, and richness. The two systems, although managed for different purposes, behaved similarly with respect to several commonly measured limnological features, most notably, those involving phosphorus. We conclude that it may be possible to use such analysis to establish reference conditions for reservoirs in a given geographic region. |
| Simple Graphical Methods for the Interpretation of Relationships Between Trophic State Variables | Robert E. Carlson; Karl E. Havens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 107 - 118 | Simple Graphical Methods for the Interpretation of Relationships Between Trophic State Variables Authors: Robert E. Carlsona; Karl E. Havensb Abstract Graphical methods are presented that can identify relationships between the trophic state variables, total phosphorus, total nitrogen, chlorophyll, and Secchi depth. The graphical approach extends the use of empirical models beyond predictions based solely on local data. Instead, the authors suggest comparing the data against an established set of predictive equations. These equations serve as a “standard model†from which deviations can be observed and inter-preted. The goal of the use of deviations from a standard model is to enhance our ability to understand relationships between important nutrient, transparency, and biological variables and to adjust our predictive models and manage-ment decisions accordingly. Examples are given of interpretations of deviations caused by nitrogen limitation, non-algal turbidity, zooplankton grazing, and dissolved water color. Keywords: trophic state; empirical models; lakes; TSI; phosphorus; chlorophyll; Secchi depth; nutrient limitation View Full Text ArticleSubscribe Affiliations: a Department of Biological Sciences, Kent State University, Kent, OH b South Florida Water Management District, West Palm Beach, FL DOI: 10.1080/07438140509354418 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 107 - 118 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Graphical methods are presented that can identify relationships between the trophic state variables, total phosphorus, total nitrogen, chlorophyll, and Secchi depth. The graphical approach extends the use of empirical models beyond predictions based solely on local data. Instead, the authors suggest comparing the data against an established set of predictive equations. These equations serve as a “standard model†from which deviations can be observed and inter-preted. The goal of the use of deviations from a standard model is to enhance our ability to understand relationships between important nutrient, transparency, and biological variables and to adjust our predictive models and manage-ment decisions accordingly. Examples are given of interpretations of deviations caused by nitrogen limitation, non-algal turbidity, zooplankton grazing, and dissolved water color. |
| Changes in Water Quality in an Urban Stream Following the Use of Organically Derived Deicing Products | Matthew Albright | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 119 - 124 | Changes in Water Quality in an Urban Stream Following the Use of Organically Derived Deicing Products Author: Matthew Albrighta Abstract Willow Brook receives runoff from Cooperstown, NY and flows into Otsego Lake, a phosphorus limited, mesotrophic waterbody. Between 1992 and 1998, the Village of Cooperstown's winter road management policy included plowing and applying abrasives (particulate material intended to increase traction) mixed with enough salt to minimize clumping. Between 1998 and 2002, Ice Ban Magicâ„¢ and Magic Minus Zeroâ„¢, both organic deicers mixed with magnesium chloride, were applied experimentally in conjunction with abrasives and salt. During the winter of 2002/2003, road treatment consisted solely of applications of salt which had been treated with Magic Minus Zeroâ„¢. Precipitation-based monitoring on Willow Brook conducted between 1991 and 2003 revealed significant declines in the export of total phosphorus, despite elevated phosphorus levels in Ice Ban Magicâ„¢ and Magic Minus Zeroâ„¢, and suspended sediment as the volume of abrasives applied to roads was reduced. Chloride levels are increasing, however. The implicit trade-offs between potential pollutants and the cost of road management in cold climates are acknowledged for management of transportation safety. Keywords: phosphorus; suspended sediment; chloride; winter road management; abrasives; Ice Ban View Full Text ArticleSubscribe Affiliation: a State University of New York College at Oneonta Biological Field Station, Cooperstown, NY DOI: 10.1080/07438140509354419 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 119 - 124 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Willow Brook receives runoff from Cooperstown, NY and flows into Otsego Lake, a phosphorus limited, mesotrophic waterbody. Between 1992 and 1998, the Village of Cooperstown's winter road management policy included plowing and applying abrasives (particulate material intended to increase traction) mixed with enough salt to minimize clumping. Between 1998 and 2002, Ice Ban Magicâ„¢ and Magic Minus Zeroâ„¢, both organic deicers mixed with magnesium chloride, were applied experimentally in conjunction with abrasives and salt. During the winter of 2002/2003, road treatment consisted solely of applications of salt which had been treated with Magic Minus Zeroâ„¢. Precipitation-based monitoring on Willow Brook conducted between 1991 and 2003 revealed significant declines in the export of total phosphorus, despite elevated phosphorus levels in Ice Ban Magicâ„¢ and Magic Minus Zeroâ„¢, and suspended sediment as the volume of abrasives applied to roads was reduced. Chloride levels are increasing, however. The implicit trade-offs between potential pollutants and the cost of road management in cold climates are acknowledged for management of transportation safety. |
| Shoreline Density | Richard A. Osgood | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 125 - 126 | Shoreline Density Author: Richard A. Osgooda Abstract A new morphometric index, shoreline density, is presented. Shoreline density, the length of shoreline divided by surface area, is useful for evaluating or comparing shoreline-associated impacts. Keywords: Shoreline development index; shoreline development; shoreline impacts View Full Text ArticleSubscribe Affiliation: a Osgood Consulting, Shorewood, MN DOI: 10.1080/07438140509354420 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 125 - 126 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | A new morphometric index, shoreline density, is presented. Shoreline density, the length of shoreline divided by surface area, is useful for evaluating or comparing shoreline-associated impacts. |
| Long-term Changes in Iron and Phosphorus Sedimentation in Vadnais Lake, Minnesota, Resulting from Ferric Chloride Addition and Hypolimnetic Aeration | Daniel R. Engstrom | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 95 - 105 | Long-term Changes in Iron and Phosphorus Sedimentation in Vadnais Lake, Minnesota, Resulting from Ferric Chloride Addition and Hypolimnetic Aeration Author: Daniel R. Engstroma Abstract Changes in iron (Fe) and phosphorus (P) cycling in Vadnais Lake, Minnesota, resulting from ferric chloride addition and hypolimnetic aeration are evaluated by repeat sampling of bottom sediments over a 13-year period: in 1985 (pre-treatment), and in 1990 and 1998 (post-treatment). Lead-210 derived accumulation rates for Fe, Mn, total-P, and P-fractions are combined with input/output monitoring to construct chemical mass-balances for each of the three time periods. Iron injections/aeration caused large and sustained reductions in water-column total-P by increasing phosphorus removal to the sediments and preventing its recycling during stratification. Annual whole-lake phosphorus sedimentation rose from 1.26 to 1.52 t between 1985 and 1990, equivalent to a doubling of in-lake retention of external P loads (from 19% to 38%). Most of the increase is represented in the labile Fe-bound fraction. The measured sedimentary fluxes for 1985 and 1990 are similar to those calculated by difference from inflow/outflow data, whereas measured P sedimentation in 1998 (2.43 t·yr-1) is three times higher than that estimated from input/output calculations. These results suggest surface enrichment by upward P diffusion within the sediment column. Present-day Fe accumulation rates (24 t·yr-1) are 33% greater than those immediately preceding treatment and 14% greater than pre-settlement fluxes (21 t·yr-1). The 6 t·yr-1 increase in Fe accumulation between 1985 and 1998 is roughly equal to the rate of iron injection to Vadnais Lake. Fifty-four tons of iron addition to the Lambert Creek tributary between 1990 and 1998 have also enriched littoral sediments in Fe, P, and Mn near the creek's outfall. These engineering solutions have substantially improved water quality in Vadnais Lake, but continued hypolimnetic aeration will be required to prevent internal phosphorus loading from the large reservoir of labile sedimentary P that has accumulated since treatment began. Keywords: Iron addition; hypolimnetic aeration; sedimentation; phosphorus inactivation; internal loading View Full Text ArticleSubscribe Affiliation: a St. Croix Watershed Research Station Science Museum of Minnesota, Marine on St. Croix, MN DOI: 10.1080/07438140509354417 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 95 - 105 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Changes in iron (Fe) and phosphorus (P) cycling in Vadnais Lake, Minnesota, resulting from ferric chloride addition and hypolimnetic aeration are evaluated by repeat sampling of bottom sediments over a 13-year period: in 1985 (pre-treatment), and in 1990 and 1998 (post-treatment). Lead-210 derived accumulation rates for Fe, Mn, total-P, and P-fractions are combined with input/output monitoring to construct chemical mass-balances for each of the three time periods. Iron injections/aeration caused large and sustained reductions in water-column total-P by increasing phosphorus removal to the sediments and preventing its recycling during stratification. Annual whole-lake phosphorus sedimentation rose from 1.26 to 1.52 t between 1985 and 1990, equivalent to a doubling of in-lake retention of external P loads (from 19% to 38%). Most of the increase is represented in the labile Fe-bound fraction. The measured sedimentary fluxes for 1985 and 1990 are similar to those calculated by difference from inflow/outflow data, whereas measured P sedimentation in 1998 (2.43 t·yr-1) is three times higher than that estimated from input/output calculations. These results suggest surface enrichment by upward P diffusion within the sediment column. Present-day Fe accumulation rates (24 t·yr-1) are 33% greater than those immediately preceding treatment and 14% greater than pre-settlement fluxes (21 t·yr-1). The 6 t·yr-1 increase in Fe accumulation between 1985 and 1998 is roughly equal to the rate of iron injection to Vadnais Lake. Fifty-four tons of iron addition to the Lambert Creek tributary between 1990 and 1998 have also enriched littoral sediments in Fe, P, and Mn near the creek's outfall. These engineering solutions have substantially improved water quality in Vadnais Lake, but continued hypolimnetic aeration will be required to prevent internal phosphorus loading from the large reservoir of labile sedimentary P that has accumulated since treatment began. |
| Use of IDEXX Colilert-18® and Quanti-Tray/2000 as a Rapid and Simple Enumeration Method for the Implementation of Recreational Water Monitoring and Notification Programs | Julie L. Kinzelman; Ajaib Singh; Clem Ng; Kathy R. Pond; Robert C. Bagley; Stephen Gradus | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 73 - 77 | Use of IDEXX Colilert-18® and Quanti-Tray/2000 as a Rapid and Simple Enumeration Method for the Implementation of Recreational Water Monitoring and Notification Programs Authors: Julie L. Kinzelmanab; Ajaib Singhc; Clem Ngc; Kathy R. Pondb; Robert C. Bagleya; Stephen Gradusc Abstract The Beaches Environmental Assessment and Coastal Health Act of 2002 (BEACH Act) requires the implementation and/or expansion of routine recreational water quality monitoring programs in all United States coastal recreational waters, including the Great Lakes, to be adopted by 2004. While the standardization of sample collection and laboratory testing protocols is essential, the ability to provide timely public notification is an equally important element. In preparation for the implementation of the BEACH Act in Wisconsin the communities of Milwaukee and Racine investigated the use of IDEXX Colilert-18, Quanti-Tray/2000 (IDEXX) as a means to reduce the time necessary for public notification of recreational water quality while still providing accurate and consistent test results. Conducted over a 2-year period, this study compared two methods, IDEXX and an approved USEPA membrane filtration method (m-Tec agar), for the quantitative determination of Escherichia coli in split samples from fresh water beaches. ANOVA analysis of regression relation indicated no significant difference between the data sets obtained using these methodologies (p < 0.001). Parallel studies conducted in the United Kingdom produced similar results. The fact that IDEXX decreases the time from sample collection to public notification by over six hours coupled with its ease of use and consistent results make this method an attractive choice for the implementation of fresh water and marine beach management programs. Keywords: E. coli; BEACH Act of 2000; recreational water quality monitoring View Full Text ArticleSubscribe Affiliations: a City of Racine Health Department Laboratory, Racine, WI b Robens Centre for Public and Environmental Health, Univ. of Surrey, Guildford, Surrey, UK c City of Milwaukee Health Department Laboratory, Milwaukee, WI DOI: 10.1080/07438140509354414 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 73 - 77 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | The Beaches Environmental Assessment and Coastal Health Act of 2002 (BEACH Act) requires the implementation and/or expansion of routine recreational water quality monitoring programs in all United States coastal recreational waters, including the Great Lakes, to be adopted by 2004. While the standardization of sample collection and laboratory testing protocols is essential, the ability to provide timely public notification is an equally important element. In preparation for the implementation of the BEACH Act in Wisconsin the communities of Milwaukee and Racine investigated the use of IDEXX Colilert-18, Quanti-Tray/2000 (IDEXX) as a means to reduce the time necessary for public notification of recreational water quality while still providing accurate and consistent test results. Conducted over a 2-year period, this study compared two methods, IDEXX and an approved USEPA membrane filtration method (m-Tec agar), for the quantitative determination of Escherichia coli in split samples from fresh water beaches. ANOVA analysis of regression relation indicated no significant difference between the data sets obtained using these methodologies (p < 0.001). Parallel studies conducted in the United Kingdom produced similar results. The fact that IDEXX decreases the time from sample collection to public notification by over six hours coupled with its ease of use and consistent results make this method an attractive choice for the implementation of fresh water and marine beach management programs. |
| Evaluation of the Potential Adverse Effects of Lake Inflow Treatment with Alum | Keith M. Pilgrim; Patrick L. Brezonik | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 77 - 87 | Evaluation of the Potential Adverse Effects of Lake Inflow Treatment with Alum Authors: Keith M. Pilgrimab; Patrick L. Brezonikac Abstract Laboratory and field investigations at Fish Lake in Eagan, MN, and Tanners Lake in Oakdale, MN, were conducted to evaluate the potential adverse effects of using alum to treat lake inflows. Detention ponds are used at both sites to promote settling of alum floc before discharge to the lake. Tests in a 1.5 m column designed to estimate settling in detention ponds showed nearly complete Al settling by 6 h. Final residual Al concentrations were affected only slightly by dose. Average concentrations of total Al entering Fish Lake were 346 and 458 μg Al L-1 at doses of 1 and 8 mg Al L-1, and average in-lake concentrations were 70 and 152 μg L-1. Aluminum settled in Fish Lake at a rate of 74 m y-1. Average Al concentrations in Tanners Lake inflow were higher, but Al concentrations in the lake were lower because of its greater size. The settling pond at Fish Lake protected benthic invertebrates in the lake, but floc accumulation during treatment at 8 mg Al L-1 eliminated nearly all invertebrates in the pond. Concentrations of Al that showed no observed mortality effects (NOECs) were assembled from literature, and a measure of unbound, positively charged Al species (Allm) was compared to the NOECs to evaluate potential aquatic toxicity from alum treatment. The potential risk of aquatic toxicity should be negligible if treated water entering the lake has a pH > 6.0. Keywords: alum treatment; aquatic toxicity; benthic invertebrates; aluminum; speciation View Full Text ArticleSubscribe Affiliations: a Water Resources Science Graduate Program and Department of Civil Engineering, University of Minnesota, Minneapolis, MN b Barr Engineering, Minneapolis, MN c National Science Foundation, Arlington, VA DOI: 10.1080/07438140509354415 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 77 - 87 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Laboratory and field investigations at Fish Lake in Eagan, MN, and Tanners Lake in Oakdale, MN, were conducted to evaluate the potential adverse effects of using alum to treat lake inflows. Detention ponds are used at both sites to promote settling of alum floc before discharge to the lake. Tests in a 1.5 m column designed to estimate settling in detention ponds showed nearly complete Al settling by 6 h. Final residual Al concentrations were affected only slightly by dose. Average concentrations of total Al entering Fish Lake were 346 and 458 μg Al L-1 at doses of 1 and 8 mg Al L-1, and average in-lake concentrations were 70 and 152 μg L-1. Aluminum settled in Fish Lake at a rate of 74 m y-1. Average Al concentrations in Tanners Lake inflow were higher, but Al concentrations in the lake were lower because of its greater size. The settling pond at Fish Lake protected benthic invertebrates in the lake, but floc accumulation during treatment at 8 mg Al L-1 eliminated nearly all invertebrates in the pond. Concentrations of Al that showed no observed mortality effects (NOECs) were assembled from literature, and a measure of unbound, positively charged Al species (Allm) was compared to the NOECs to evaluate potential aquatic toxicity from alum treatment. The potential risk of aquatic toxicity should be negligible if treated water entering the lake has a pH > 6.0. |
| Relationship Between Largemouth Bass Recruitment and Water Level Dynamics in a Puerto Rico Reservoir | Ozcan Ozen; Richard L. Noble | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 21 | 1 | 2005 | 89 - 95 | Relationship Between Largemouth Bass Recruitment and Water Level Dynamics in a Puerto Rico Reservoir Authors: Ozcan Ozenab; Richard L. Noblea Abstract Recruitment of largemouth bass at age-1 in a Puerto Rico reservoir can be predicted from water level variables of the previous year. Age-1 largemouth bass electrofishing catch-per-unit-effort (CPUE) as an index of year-class strength varied five fold between 1994 and 2001 in Lucchetti Reservoir, Puerto Rico. The CPUE of age-1 largemouth bass was higher in years when the water level of the previous years (1993-2000) remained high during the spawning period (January-June). The greatest water level drop (11.2 m) during the spawning period was observed in 1999, resulting in a water volume decrease of 66.5%, which corresponded to the lowest recruitment (CPUE 24.2 fish·h-1). With only 2.6 m of water level drop and 18.3% water volume decrease during the spawning period, the 1995 largemouth bass cohort was the strongest (CPUE 128.3 fish·h-1). The effect of these hydrological variables on largemouth bass recruitment appeared to be exponential rather than linear. Age-1 largemouth bass comprise the majority of the fishable stock in Lucchetti Reservoir, and the stock is typically below carrying capacity. Thus, the potential exists to adopt a water level management plan during the spawning period of largemouth bass to ensure successful largemouth bass recruitment into the next year's fishable stock. Keywords: tropical reservoir; hydrology; water level; largemouth bass; recruitment View Full Text ArticleSubscribe Affiliations: a Department of Zoology, North Carolina State University, Raleigh, NC, USA b Canakkale Onsekiz Mart Universitesi, Su Urunleri Fakultesi, Canakkale, TURKEY DOI: 10.1080/07438140509354416 Published in: Lake and Reservoir Management, Volume 21, Issue 1 March 2005 , pages 89 - 95 Publication Frequency: 4 issues per year First Published on: 01 March 2005 Formats available: PDF (English) | Recruitment of largemouth bass at age-1 in a Puerto Rico reservoir can be predicted from water level variables of the previous year. Age-1 largemouth bass electrofishing catch-per-unit-effort (CPUE) as an index of year-class strength varied five fold between 1994 and 2001 in Lucchetti Reservoir, Puerto Rico. The CPUE of age-1 largemouth bass was higher in years when the water level of the previous years (1993-2000) remained high during the spawning period (January-June). The greatest water level drop (11.2 m) during the spawning period was observed in 1999, resulting in a water volume decrease of 66.5%, which corresponded to the lowest recruitment (CPUE 24.2 fish·h-1). With only 2.6 m of water level drop and 18.3% water volume decrease during the spawning period, the 1995 largemouth bass cohort was the strongest (CPUE 128.3 fish·h-1). The effect of these hydrological variables on largemouth bass recruitment appeared to be exponential rather than linear. Age-1 largemouth bass comprise the majority of the fishable stock in Lucchetti Reservoir, and the stock is typically below carrying capacity. Thus, the potential exists to adopt a water level management plan during the spawning period of largemouth bass to ensure successful largemouth bass recruitment into the next year's fishable stock. |
| Temperature Stratification and Mixing Dynamics in a Shallow Lake With Submersed Macrophytes | William R. Herb; Heinz G. Stefan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 4 | 2004 | 296 - 308 | Temperature Stratification and Mixing Dynamics in a Shallow Lake With Submersed Macrophytes Authors: William R. Herba; Heinz G. Stefana Abstract This paper describes an investigation of temperature stratification and vertical mixing in lacustrine macrophyte beds. Field measurements in a shallow lake show pronounced diel temperature dynamics, driven by surface heat transfer. The temperature stratification data also indicate a significant dependence of vertical mixing characteristics on macrophyte stand height. While natural convective mixing during night-time cooling was rather uniform between measurement sites, wind-driven mixing during the day was significantly attenuated in dense, full-depth macrophyte beds, resulting in increased stratification and higher maximum surface temperatures. An unsteady, one-dimensional heat transfer model has been formulated to simulate temperature dynamics in shallow lakes with submersed macrophytes. Surface mixed layer dynamics are successfully modeled at time scales down to 1 hour, using an integral energy model formulated to include the effect of light attenuation and turbulent kineuc energy dissipation by submersed macrophytes. The results of this study have implications for the management of water quality and ecology of shallow lakes, as variation of thermal stratification and mixing likely has corresponding effects on the transport of dissolved oxygen and nutrients. Keywords: heat transfer model; shallow lake; stratification; submersed macrophytes; water temperature; wind mixing View Full Text ArticleSubscribe Affiliation: a St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, USA DOI: 10.1080/07438140409354159 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 December 2004 Formats available: PDF (English) | This paper describes an investigation of temperature stratification and vertical mixing in lacustrine macrophyte beds. Field measurements in a shallow lake show pronounced diel temperature dynamics, driven by surface heat transfer. The temperature stratification data also indicate a significant dependence of vertical mixing characteristics on macrophyte stand height. While natural convective mixing during night-time cooling was rather uniform between measurement sites, wind-driven mixing during the day was significantly attenuated in dense, full-depth macrophyte beds, resulting in increased stratification and higher maximum surface temperatures. An unsteady, one-dimensional heat transfer model has been formulated to simulate temperature dynamics in shallow lakes with submersed macrophytes. Surface mixed layer dynamics are successfully modeled at time scales down to 1 hour, using an integral energy model formulated to include the effect of light attenuation and turbulent kineuc energy dissipation by submersed macrophytes. The results of this study have implications for the management of water quality and ecology of shallow lakes, as variation of thermal stratification and mixing likely has corresponding effects on the transport of dissolved oxygen and nutrients. |
| Water Level Drawdown Affects Physical and Biogeochemical Properties of Littoral Sediments of a Reservoir and a Natural Lake | P. C. Furey; R. N. Nordin; A. Mazumder | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 4 | 2004 | 280 - 295 | Water Level Drawdown Affects Physical and Biogeochemical Properties of Littoral Sediments of a Reservoir and a Natural Lake Authors: P. C. Fureya; R. N. Nordinb; A. Mazumderb Abstract To determine the influence of water level drawdown on littoral areas, we compared the temporal and spatial changes in the water column and sediment in the littoral region of a drinking water reservoir and a natural lake. The reservoir (Sooke) experiences more than six meters of seasonal drawdown compared to a nearby, morphometrically and trophically similar lake (Shawnigan) that experiences less than one meter of drawdown. A greater drawdown in Sooke increased the littoral area and resulted in more littoral water column mixing, more solar warming, and higher PAR at a greater range of littoral depths than in Shawnigan. Based on sediment physical and chemical characteristics, sites farthest from shore were most similar, whereas sites in the drawdown exposure zone of Sooke and the upper littoral area of Shawnigan showed the largest differences. Low macrophyte abundance and loss of fine sediments, nutrients, and organic matter from the drawdown exposure zone in Sooke compared to the equivalent littoral area in Shawnigan suggest that drawdown enhances sediment erosion and focusing. Element and stable isotope ratios of sediment carbon and nitrogen suggest organic matter in the drawdown zone in Sooke is more allochthonous in origin and is coupled more strongly with deeper sites than in Shawnigan. Organic matter source and distribution also suggests that the littoral area extends out farther in Sooke than Shawnigan. This study demonstrates that drawdown has the potential to fundamentally change reservoir littoral sediment and biogeochemical characteristics. Understanding how littoral zones in reservoirs respond to drawdown compared to natural lakes may help water managers make more ecologically informed decisions regarding drawdown impacts on the ecology of littoral zones and water quality. Keywords: drinking water reservoir; littoral; sediment; macrophyte; nutrient; organic matter; biogeochemistry; stable isotope View Full Text ArticleSubscribe Affiliations: a Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, USA b Water and Watershed Ecology Program Department of Biology, University of Victoria, Victoria, British Columbia, Canada DOI: 10.1080/07438140409354158 Published in: Lake and Reservoir Management, Volume 20, Issue 4 December 2004 , pages 280 - 295 Publication Frequency: 4 issues per year First Published on: 01 December 2004 Formats available: PDF (English) | To determine the influence of water level drawdown on littoral areas, we compared the temporal and spatial changes in the water column and sediment in the littoral region of a drinking water reservoir and a natural lake. The reservoir (Sooke) experiences more than six meters of seasonal drawdown compared to a nearby, morphometrically and trophically similar lake (Shawnigan) that experiences less than one meter of drawdown. A greater drawdown in Sooke increased the littoral area and resulted in more littoral water column mixing, more solar warming, and higher PAR at a greater range of littoral depths than in Shawnigan. Based on sediment physical and chemical characteristics, sites farthest from shore were most similar, whereas sites in the drawdown exposure zone of Sooke and the upper littoral area of Shawnigan showed the largest differences. Low macrophyte abundance and loss of fine sediments, nutrients, and organic matter from the drawdown exposure zone in Sooke compared to the equivalent littoral area in Shawnigan suggest that drawdown enhances sediment erosion and focusing. Element and stable isotope ratios of sediment carbon and nitrogen suggest organic matter in the drawdown zone in Sooke is more allochthonous in origin and is coupled more strongly with deeper sites than in Shawnigan. Organic matter source and distribution also suggests that the littoral area extends out farther in Sooke than Shawnigan. This study demonstrates that drawdown has the potential to fundamentally change reservoir littoral sediment and biogeochemical characteristics. Understanding how littoral zones in reservoirs respond to drawdown compared to natural lakes may help water managers make more ecologically informed decisions regarding drawdown impacts on the ecology of littoral zones and water quality. |
| Impacts of Metal Salt Addition on Water Chemistry of Lake Elsinore, California: 2. Calcium Salts | Michael A. Anderson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 4 | 2004 | 270 - 279 | Impacts of Metal Salt Addition on Water Chemistry of Lake Elsinore, California: 2. Calcium Salts Author: Michael A. Andersona Abstract Laboratory studies using water samples collected from Lake Elsinore in June 2002 demonstrated that addition of CA2+ substantively changed the water chemistry. The addition of agricultural gypsum, rock gypsum and CaCl2 all lowered equilibrium pH and alkalinity levels, while increasing the dissolved Ca2+ concentration. Solution pH decreased linearly with increasing Ca2+ dose, from 9.0 with no added Ca2+, to about 8.4 at a dose of 200 mg·L-1. Alkalinity decreased from 10.5 to about 3.5 meq·L-1, while dissolved Ca2+ levels increased from 20.6 to approximately 100 mg·L-1 over this same dose range. Addition of CaO and Ca(OH)2 had a comparatively small effect on equilibrium chemistry and maintained high pH, high alkalinity and low Ca2+ levels in the water. The kinetics of these changes were quite slow; equilibrium was generally reached between 4-7 days depending upon Ca-salt used and the rate of mixing. The Ca-salt additions resulted in modest (30-40%) reductions in total phosphorus (TP) and chlorophyll levels. Sorption and core-flux experiments demonstrated limited capacity of precipitated CaCO3 to sorb soluble-reactive phosphorus (SRP). More substantial removal was achieved, however, via coprecipitation of SRP with CaCO3 formed in situ from Ca2+-amended recycled water added to Lake Elsinore water, although removal efficiencies remained well below those typically achieved with alum. Based upon these findings, some general recommendations can be made about Ca2+ addition to lakes for the control of phosphorus: (i) Ca2+ addition to lakes will be more effective during periods of high SRP concentrations; (ii) addition of Ca-salts that promote coprecipitation of SRP with CaCO3 formed in situ is more effective at removing SRP from the water column than adsorption to preformed CaCO3; and (iii) the form and dose of the Ca-salt dramatically influences the final chemical condition of the water. Keywords: calcium; chemistry; Lake Elsinore View Full Text ArticleSubscribe Affiliation: a Department of Environmental Sciences, University of California, Riverside, CA DOI: 10.1080/07438140409354157 Published in: Lake and Reservoir Management, Volume 20, Issue 4 December 2004 , pages 270 - 279 Publication Frequency: 4 issues per year First Published on: 01 December 2004 Formats available: PDF (English) | Laboratory studies using water samples collected from Lake Elsinore in June 2002 demonstrated that addition of CA2+ substantively changed the water chemistry. The addition of agricultural gypsum, rock gypsum and CaCl2 all lowered equilibrium pH and alkalinity levels, while increasing the dissolved Ca2+ concentration. Solution pH decreased linearly with increasing Ca2+ dose, from 9.0 with no added Ca2+, to about 8.4 at a dose of 200 mg·L-1. Alkalinity decreased from 10.5 to about 3.5 meq·L-1, while dissolved Ca2+ levels increased from 20.6 to approximately 100 mg·L-1 over this same dose range. Addition of CaO and Ca(OH)2 had a comparatively small effect on equilibrium chemistry and maintained high pH, high alkalinity and low Ca2+ levels in the water. The kinetics of these changes were quite slow; equilibrium was generally reached between 4-7 days depending upon Ca-salt used and the rate of mixing. The Ca-salt additions resulted in modest (30-40%) reductions in total phosphorus (TP) and chlorophyll levels. Sorption and core-flux experiments demonstrated limited capacity of precipitated CaCO3 to sorb soluble-reactive phosphorus (SRP). More substantial removal was achieved, however, via coprecipitation of SRP with CaCO3 formed in situ from Ca2+-amended recycled water added to Lake Elsinore water, although removal efficiencies remained well below those typically achieved with alum. Based upon these findings, some general recommendations can be made about Ca2+ addition to lakes for the control of phosphorus: (i) Ca2+ addition to lakes will be more effective during periods of high SRP concentrations; (ii) addition of Ca-salts that promote coprecipitation of SRP with CaCO3 formed in situ is more effective at removing SRP from the water column than adsorption to preformed CaCO3; and (iii) the form and dose of the Ca-salt dramatically influences the final chemical condition of the water. |
| Flood-related, Organic-carbon Anomalies as Possible Temporal Markers in Reservoir Bottom Sediments | Kyle E. Juracek | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 4 | 2004 | 309 - 321 | Flood-related, Organic-carbon Anomalies as Possible Temporal Markers in Reservoir Bottom Sediments Author: Kyle E. Juraceka Abstract Results of a study of sediment cores from four reservoirs in the upper Mississippi River Basin, USA, indicated that anomalous organic carbon concentrations associated with flood deposits may provide detectable temporal markers in reservoir bottom sediments. Temporal markers are needed for reservoir sediment studies to date sediment layers deposited between the 1963-64 cesium-137 peak and the present. For two of four reservoirs studied, anomalously low organic carbon concentrations were measured for a sample interval in the upper part of a sediment core. The anomalous interval was interpreted to have been deposited during the July 1993 flood that affected a large area of the upper Mississippi River Basin. Potentially, the July 1993 flood deposit may be used as a temporal marker in reservoir bottom sediments in parts of the basin affected by the flood. Several uncertainties remain regarding the viability of organic carbon as a temporal marker including the combination of flood, basin, and reservoir characteristics required to produce a recognizable organic carbon marker in the bottom sediment and the optimal sampling strategy needed to detect the marker in a sediment core. It is proposed that flood duration and basin size may be important factors as to whether or not an anomalous and detectable organic carbon layer is deposited in a reservoir. Keywords: organic carbon; anomaly; flood; age dating; reservoir; sediment View Full Text ArticleSubscribe Affiliation: a U.S. Geological Survey, Lawrence, Kansas, USA DOI: 10.1080/07438140409354160 Published in: Lake and Reservoir Management, Volume 20, Issue 4 December 2004 , pages 309 - 321 Publication Frequency: 4 issues per year First Published on: 01 December 2004 Formats available: PDF (English) | Results of a study of sediment cores from four reservoirs in the upper Mississippi River Basin, USA, indicated that anomalous organic carbon concentrations associated with flood deposits may provide detectable temporal markers in reservoir bottom sediments. Temporal markers are needed for reservoir sediment studies to date sediment layers deposited between the 1963-64 cesium-137 peak and the present. For two of four reservoirs studied, anomalously low organic carbon concentrations were measured for a sample interval in the upper part of a sediment core. The anomalous interval was interpreted to have been deposited during the July 1993 flood that affected a large area of the upper Mississippi River Basin. Potentially, the July 1993 flood deposit may be used as a temporal marker in reservoir bottom sediments in parts of the basin affected by the flood. Several uncertainties remain regarding the viability of organic carbon as a temporal marker including the combination of flood, basin, and reservoir characteristics required to produce a recognizable organic carbon marker in the bottom sediment and the optimal sampling strategy needed to detect the marker in a sediment core. It is proposed that flood duration and basin size may be important factors as to whether or not an anomalous and detectable organic carbon layer is deposited in a reservoir. |
| Phosphorus Dynamics in Jessie Lake: Mass Flux Across the Sediment-Water Interface | Hong Wang; Miki Hondzo; Brenda Stauffer; Bruce Wilson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 4 | 2004 | 333 - 346 | Phosphorus Dynamics in Jessie Lake: Mass Flux Across the Sediment-Water Interface Authors: Hong Wanga; Miki Hondzob; Brenda Staufferc; Bruce Wilsond Abstract Field and laboratory measurements were conducted to determine phosphorus (P) fluxes at the sediment-water interface in a thermally stratified lake. High energy dissipation rates with oscillatory fluid-flow velocities of ±0.05 m/sec were observed above the sediment-water interface at the depth of 12 m. Although the lake exhibits periods with thermal polymixis, dissolved oxygen (DO) usually exhibits a year-to-year summer clinograde DO pattern with anaerobic conditions typically encountered below 5 m to 6 m depth. In 2001, the lake was weakly dimictic with a turbulent benthic boundary layer dominated by anaerobic conditions with a pH range from 7.2 to 8.4. The concentration of P-affinity metals in the sediments ranged from 1.5 to 16.1 mg g-1, represented by Fe, Al, and Ca. The lake has relatively low P-affinity metal concentrations in the sediments, implying a low holding capacity of P. Phosphorus flux at the sediment-water interface was mediated by DO concentrations in the water column. Under aerobic conditions, no release flux of phosphorus was observed in the water column. Under anaerobic conditions, the measured release flux of P from the sediments to the overlying water was 16.93 mg·m-2·day-1. A sediment P dynamic model was used to predict conduct long-term P internal loading in the lake. If organic loading to the lake sediments continues at the rate observed in the recent past, the internal loading of P was predicted to nearly double in the next 30 years. The reduction in the organic loading of 1%, 5%, 10% and 25% will achieve reductions in the P internal loading to 9.7,3.0,0.7, and 0 mg·m-2·mday-1, respectively. Hence, future lake management options may focus on incrementally reducing internally derived P loading that will, in turn, reduce organic loading within Jessie Lake. Keywords: phosphorus; mobilization; release; sediments; fractionation; flux; internal loading View Full Text ArticleSubscribe Affiliations: a Metropolitan Council Environmental Services, St. Paul, MN b Department of Civil Engineering, St. Anthony Falls Laboratory, University of Minnesota, MN c U.S. Forest Service, Walker, MN d Minnesota Pollution Control Agency, St. Paul, MN DOI: 10.1080/07438140409354162 Published in: Lake and Reservoir Management, Volume 20, Issue 4 December 2004 , pages 333 - 346 Publication Frequency: 4 issues per year First Published on: 01 December 2004 Formats available: PDF (English) | Field and laboratory measurements were conducted to determine phosphorus (P) fluxes at the sediment-water interface in a thermally stratified lake. High energy dissipation rates with oscillatory fluid-flow velocities of ±0.05 m/sec were observed above the sediment-water interface at the depth of 12 m. Although the lake exhibits periods with thermal polymixis, dissolved oxygen (DO) usually exhibits a year-to-year summer clinograde DO pattern with anaerobic conditions typically encountered below 5 m to 6 m depth. In 2001, the lake was weakly dimictic with a turbulent benthic boundary layer dominated by anaerobic conditions with a pH range from 7.2 to 8.4. The concentration of P-affinity metals in the sediments ranged from 1.5 to 16.1 mg g-1, represented by Fe, Al, and Ca. The lake has relatively low P-affinity metal concentrations in the sediments, implying a low holding capacity of P. Phosphorus flux at the sediment-water interface was mediated by DO concentrations in the water column. Under aerobic conditions, no release flux of phosphorus was observed in the water column. Under anaerobic conditions, the measured release flux of P from the sediments to the overlying water was 16.93 mg·m-2·day-1. A sediment P dynamic model was used to predict conduct long-term P internal loading in the lake. If organic loading to the lake sediments continues at the rate observed in the recent past, the internal loading of P was predicted to nearly double in the next 30 years. The reduction in the organic loading of 1%, 5%, 10% and 25% will achieve reductions in the P internal loading to 9.7,3.0,0.7, and 0 mg·m-2·mday-1, respectively. Hence, future lake management options may focus on incrementally reducing internally derived P loading that will, in turn, reduce organic loading within Jessie Lake. |
| Erratum | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 4 | 2004 | 269 | Erratum View Full Text ArticleSubscribe DOI: 10.1080/07438140409354156 Published in: Lake and Reservoir Management, Volume 20, Issue 4 December 2004 , page 269 Publication Frequency: 4 issues per year First Published on: 01 December 2004 Formats available: PDF (English) | |
| Small-Plot, Low-Dose Treatments of Triclopyr for Selective Control of Eurasian Watermilfoil | Angela G. Poovey; Kurt D. Getsinger; John G. Skogerboe; Tyler J. Koschnick; John D. Madsen; R. Michael Stewart | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 4 | 2004 | 322 - 332 | Small-Plot, Low-Dose Treatments of Triclopyr for Selective Control of Eurasian Watermilfoil Authors: Angela G. Pooveya; Kurt D. Getsingera; John G. Skogerboea; Tyler J. Koschnickb; John D. Madsenc; R. Michael Stewartd Abstract Small-plot treatments of triclopyr were conducted on Lake Minnetonka and Lake Minnewashta, MN, during June 1998 to investigate the herbicide's potential to selectively control Eurasian watermilfoil (Myriophyllum spicatum L.) at low doses. Applications were made on 1-ha plots with rates based on plot type: references (0 mg acid equivalent (ae)·L-1), protected plots (0.5 mg ae·L-1), semi-protected plots(1.0 mgae·L-1), and unprotected plots (1.5 mgae·L-1). Plot protection was a function of potential mixing in the water column. Herbicide residues were monitored to determine dissipation 1 through 72 h post treatment. Samples were analyzed with both a high performance liquid chromatography technique and an enzyme-linked immunosorbent assay method. Results from these two analytical techniques were compared, and found equivalent (R2 = 0.96). Triclopyr had a relatively short half-life for each treatment (3.5 hr at 0.5 mg ae·L-1, 2.9 hr at 1.0 mg ae·L-1, and 4.2 hr at 1.5 mg ae·L-1). At 8 weeks post treatment, there was a 30 to 45% reduction in Eurasian watermilfoil distribution. Greatest Eurasian watermilfoil control was achieved in plots using higher triclopyr rates. Frequency of native plants decreased by 24% in the untreated reference plot, 20% in the 0.5 mg ae·L-1 plot and 6% in the 1.0 and 1.5 mg ae·L-1 plots. Mean species per point, however, either increased or remained unchanged in seven of the nine treated plots. Decline of native plants may be partially attributed to the onset of fall senescence. Larger contiguous areas, higher triclopyr rates, and sequential applications may be required to enhance Eurasian watermilfoil control in small-plot, partial lake treatments. Keywords: aquatic plant control; Myriophyllum spicatum; herbicide; Renovate®3; ELISA View Full Text ArticleSubscribe Affiliations: a U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS b Center for Aquatic and Invasive Plants, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL c Mississippi State University, GeoResources Institute, Mississippi State, MS d U.S. Army Engineer District, Vicksburg, Vicksburg, MS DOI: 10.1080/07438140409354161 Published in: Lake and Reservoir Management, Volume 20, Issue 4 December 2004 , pages 322 - 332 Publication Frequency: 4 issues per year First Published on: 01 December 2004 Formats available: PDF (English) | Small-plot treatments of triclopyr were conducted on Lake Minnetonka and Lake Minnewashta, MN, during June 1998 to investigate the herbicide's potential to selectively control Eurasian watermilfoil (Myriophyllum spicatum L.) at low doses. Applications were made on 1-ha plots with rates based on plot type: references (0 mg acid equivalent (ae)·L-1), protected plots (0.5 mg ae·L-1), semi-protected plots(1.0 mgae·L-1), and unprotected plots (1.5 mgae·L-1). Plot protection was a function of potential mixing in the water column. Herbicide residues were monitored to determine dissipation 1 through 72 h post treatment. Samples were analyzed with both a high performance liquid chromatography technique and an enzyme-linked immunosorbent assay method. Results from these two analytical techniques were compared, and found equivalent (R2 = 0.96). Triclopyr had a relatively short half-life for each treatment (3.5 hr at 0.5 mg ae·L-1, 2.9 hr at 1.0 mg ae·L-1, and 4.2 hr at 1.5 mg ae·L-1). At 8 weeks post treatment, there was a 30 to 45% reduction in Eurasian watermilfoil distribution. Greatest Eurasian watermilfoil control was achieved in plots using higher triclopyr rates. Frequency of native plants decreased by 24% in the untreated reference plot, 20% in the 0.5 mg ae·L-1 plot and 6% in the 1.0 and 1.5 mg ae·L-1 plots. Mean species per point, however, either increased or remained unchanged in seven of the nine treated plots. Decline of native plants may be partially attributed to the onset of fall senescence. Larger contiguous areas, higher triclopyr rates, and sequential applications may be required to enhance Eurasian watermilfoil control in small-plot, partial lake treatments. |
| Biomanipulation: A Classic Example in a Shallow Eutrophic Pond | Matthew F. Albright; Willard N. Harman; Wesley T. Tibbits; Michael S. Gray; David M. Warner; Rebecca J. Hamway | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 4 | 2004 | 263 - 269 | Biomanipulation: A Classic Example in a Shallow Eutrophic Pond Authors: Matthew F. Albrighta; Willard N. Harmana; Wesley T. Tibbitsa; Michael S. Graya; David M. Warnerb; Rebecca J. Hamwayc Abstract Mod Pond, Otsego County, New York, is an artificial impoundment created by the damming of a natural wetland in 1939. It was dominated by blue-green algal blooms between at least 1970-1998. During that time a few scattered clones of sedges (Cyperaceae) along the shoreline were the only vascular plants present. The zooplankton community was dominated by small individuals, primarily rotifers, which were unable to effectively graze the algal community. During this interval, golden shiner (Notemigonus crysoleucas) and brown bullhead (Ictalurus nebulosus) made up the entire fish community. Largemouth and smallmouth bass (Micropterus dolomieu and M. salmoides) were added between 1998 and spring 1999. Golden shiner recruitment functionally ended at that time, and by 2002 they had been virtually eliminated. Secchi transparencies increased and mean chlorophyll a decreased significantly (p<0.05), with algal blooms becoming practically nonexistent. Water weed (Elodea canadensis) nowcovers the bottom of most of the pond, reaching the surface in many areas up to 2 m in depth. Increased transparency, as well as potential changes in nutrient dynamics, both indirectly brought about by the addition of piscivorous fish, apparently has enabled Elodea to out-compete plank tonic algae for available nutrients. This documents a situation where top-down management of the fish community has affected the biota and water quality through trophic cascades. The introduction of piscivorous fish (top-down management) may be used to manage water quality through increased algal grazing by zooplankton. However, a substantial increase in macrophytes, as documented here, may be an outcome. Keywords: biomanipulation; trophic cascade; top-down management; eutrophic pond; golden shiner; piscivory View Full Text ArticleSubscribe Affiliations: a State University of New York College at Oneonta Biological Field Station, Cooperstown, NY b Department of Natural Resources, Cornell University Biological Field Station, Bridgeport, NY c Dickinson College, Carlisle, PA DOI: 10.1080/07438140409354155 Published in: Lake and Reservoir Management, Volume 20, Issue 4 December 2004 , pages 263 - 269 Publication Frequency: 4 issues per year First Published on: 01 December 2004 Formats available: PDF (English) | Mod Pond, Otsego County, New York, is an artificial impoundment created by the damming of a natural wetland in 1939. It was dominated by blue-green algal blooms between at least 1970-1998. During that time a few scattered clones of sedges (Cyperaceae) along the shoreline were the only vascular plants present. The zooplankton community was dominated by small individuals, primarily rotifers, which were unable to effectively graze the algal community. During this interval, golden shiner (Notemigonus crysoleucas) and brown bullhead (Ictalurus nebulosus) made up the entire fish community. Largemouth and smallmouth bass (Micropterus dolomieu and M. salmoides) were added between 1998 and spring 1999. Golden shiner recruitment functionally ended at that time, and by 2002 they had been virtually eliminated. Secchi transparencies increased and mean chlorophyll a decreased significantly (p<0.05), with algal blooms becoming practically nonexistent. Water weed (Elodea canadensis) nowcovers the bottom of most of the pond, reaching the surface in many areas up to 2 m in depth. Increased transparency, as well as potential changes in nutrient dynamics, both indirectly brought about by the addition of piscivorous fish, apparently has enabled Elodea to out-compete plank tonic algae for available nutrients. This documents a situation where top-down management of the fish community has affected the biota and water quality through trophic cascades. The introduction of piscivorous fish (top-down management) may be used to manage water quality through increased algal grazing by zooplankton. However, a substantial increase in macrophytes, as documented here, may be an outcome. |
| The Phosphorus-Chlorophyll Relationship in Lakes: Potential Influences of Color and Mixing Regime | Karl E. Havens; Gertrud K. Nürnberg | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 3 | 2004 | 188 - 196 | The Phosphorus-Chlorophyll Relationship in Lakes: Potential Influences of Color and Mixing Regime Authors: Karl E. Havensa; Gertrud K. Nrnbergb Abstract We used summer epilimnetic means from a large dataset (369 lakes from North America, Europe, Asia, and New Zealand) to examine whether color or mixing regime significantly influence the log-log relationship between chlorophyll a (Chl a) and total phosphorus (TP) in lakes. We found no significant difference in regression models for clear (color < 10 Pt units) vs. humic lakes (color > 20 Pt units), even when data were screened so that both types of lakes were represented by the same range of TP. Likewise, there was no significant difference in regression models for mixed vs. thermally stratified lakes. Knowing that a particular lake is clear vs. humic, or mixed vs. stratified, therefore is not helpful in developing a predictive model of Chl a from TP. However, when we simultaneously considered water color and mixing regime, a potentially useful feature was identified. Mixed humic lakes have a somewhat lower (significant at p = 0.10) ratio of Chl a / TP than mixed clear water lakes, whereas no such difference exists between humic and clear water lakes that are thermally stratified. Likewise, when we plotted the Chl a / TP ratio vs. color, there was a negative slope for mixed lakes, but no significant relationship for stratified lakes. We suggest that in stratified humic lakes, which are often sheltered deep systems with a high Osgood Ratio, phytoplankton can compensate for reduced underwater irradiance by migrating toward the water surface, whereas in mixed humic lakes, that response is not possible. Lake managers dealing with mixed humic lakes might expect a lower yield of Chl a / TP than in mixed clear water lakes. Further research is needed to test this hypothesis. In any case, caution is warranted when applying such results to lake management, because given the numerous effects of high P inputs (e.g., changes in benthic invertebrate communities, biological oxygen demand, and sediment metabolism) it is unwise to focus solely on the Chl a response to protect water quality. Keywords: phosphorus-chlorophyll regression; color; mixing regime; predictive models View Full Text ArticleSubscribe Affiliations: a South Florida Water Management District, West Palm Beach, Florida, USA b Freshwater Research, Baysville, Ontario, Canada DOI: 10.1080/07438140409354243 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 September 2004 Formats available: PDF (English) | We used summer epilimnetic means from a large dataset (369 lakes from North America, Europe, Asia, and New Zealand) to examine whether color or mixing regime significantly influence the log-log relationship between chlorophyll a (Chl a) and total phosphorus (TP) in lakes. We found no significant difference in regression models for clear (color < 10 Pt units) vs. humic lakes (color > 20 Pt units), even when data were screened so that both types of lakes were represented by the same range of TP. Likewise, there was no significant difference in regression models for mixed vs. thermally stratified lakes. Knowing that a particular lake is clear vs. humic, or mixed vs. stratified, therefore is not helpful in developing a predictive model of Chl a from TP. However, when we simultaneously considered water color and mixing regime, a potentially useful feature was identified. Mixed humic lakes have a somewhat lower (significant at p = 0.10) ratio of Chl a / TP than mixed clear water lakes, whereas no such difference exists between humic and clear water lakes that are thermally stratified. Likewise, when we plotted the Chl a / TP ratio vs. color, there was a negative slope for mixed lakes, but no significant relationship for stratified lakes. We suggest that in stratified humic lakes, which are often sheltered deep systems with a high Osgood Ratio, phytoplankton can compensate for reduced underwater irradiance by migrating toward the water surface, whereas in mixed humic lakes, that response is not possible. Lake managers dealing with mixed humic lakes might expect a lower yield of Chl a / TP than in mixed clear water lakes. Further research is needed to test this hypothesis. In any case, caution is warranted when applying such results to lake management, because given the numerous effects of high P inputs (e.g., changes in benthic invertebrate communities, biological oxygen demand, and sediment metabolism) it is unwise to focus solely on the Chl a response to protect water quality. |
| Biomanipulation: A Classic Example in a Shallow Eutrophic Pond | Matthew F. Albright; Willard N. Harman; Wesley T. Tibbits; Michael S. Gray; David M. Warner; Rebecca J. Hamway | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 3 | 2004 | 181 - 187 | Biomanipulation: A Classic Example in a Shallow Eutrophic Pond Authors: Matthew F. Albrighta; Willard N. Harmana; Wesley T. Tibbitsa; Michael S. Graya; David M. Warnerb; Rebecca J. Hamwayc Abstract Moe Pond, Otsego County, New York, is an artificial impoundment created by the damming of a natural wetland in 1939. It was dominated by blue-green algal blooms between at least 1970-1998. During that time a few scattered clones of sedges (Cyperaceae) along the shoreline were the only vascular plants present. The zooplankton community was dominated by small individuals, primarily rotifers, which were unable to effectively graze the algal community. During this interval, golden shiner (Notemigonus crysoleucas) and brown bullhead (Ictalurus nebulosus) made up the entire fish community. Largemouth and smallmouth bass (Micropterus dolomieu and M. salmoides) were added between 1998 and spring 1999. Golden shiner recruitment functionally ended at that time, and by 2002 they had been virtually eliminated. Secchi transparencies increased and mean chlorophyll a decreased significantly (p<0.05), with algal blooms becoming practically nonexistent. Water weed (Elodea canadensis) now covers the bottom of most of the pond, reaching the surface in many areas up to 2 m in depth. Increased transparency, as well as potential changes in nutrient dynamics, both indirectly brought about by the addition of piscivorous fish, apparently has enabled Elodea to out-compete plank tonic algae for available nutrients. This documents a situation where top-down management of the fish community has affected the biota and water quality through trophic cascades. The introduction of piscivorous fish (top-down management) may be used to manage water quality through increased algal grazing by zooplankton. However, a substantial increase in macrophytes, as documented here, may be an outcome. Keywords: biomanipulation; trophic cascade; top-down management; eutrophic pond; golden shiner; piscivory View Full Text ArticleSubscribe Affiliations: a State University of New York College at Oneonta Biological Field Station, Cooperstown, NY b Department of Natural Resources, Cornell University Biological Field Station, Bridgeport, NY c Dickinson College, Carlisle, PA DOI: 10.1080/07438140409354242 Published in: Lake and Reservoir Management, Volume 20, Issue 3 September 2004 , pages 181 - 187 Publication Frequency: 4 issues per year First Published on: 01 September 2004 Formats available: PDF (English) | Moe Pond, Otsego County, New York, is an artificial impoundment created by the damming of a natural wetland in 1939. It was dominated by blue-green algal blooms between at least 1970-1998. During that time a few scattered clones of sedges (Cyperaceae) along the shoreline were the only vascular plants present. The zooplankton community was dominated by small individuals, primarily rotifers, which were unable to effectively graze the algal community. During this interval, golden shiner (Notemigonus crysoleucas) and brown bullhead (Ictalurus nebulosus) made up the entire fish community. Largemouth and smallmouth bass (Micropterus dolomieu and M. salmoides) were added between 1998 and spring 1999. Golden shiner recruitment functionally ended at that time, and by 2002 they had been virtually eliminated. Secchi transparencies increased and mean chlorophyll a decreased significantly (p<0.05), with algal blooms becoming practically nonexistent. Water weed (Elodea canadensis) now covers the bottom of most of the pond, reaching the surface in many areas up to 2 m in depth. Increased transparency, as well as potential changes in nutrient dynamics, both indirectly brought about by the addition of piscivorous fish, apparently has enabled Elodea to out-compete plank tonic algae for available nutrients. This documents a situation where top-down management of the fish community has affected the biota and water quality through trophic cascades. The introduction of piscivorous fish (top-down management) may be used to manage water quality through increased algal grazing by zooplankton. However, a substantial increase in macrophytes, as documented here, may be an outcome. |
| Relations Between Water Chemistry and Water Quality as Defined by Lake Users in Florida | Mark V. Hoyer; Claude D. Brown; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 3 | 2004 | 240 - 248 | Relations Between Water Chemistry and Water Quality as Defined by Lake Users in Florida Authors: Mark V. Hoyera; Claude D. Browna; Daniel E. Canfield Jr.a Abstract A lake user survey was conducted on 116 Florida lakes concurrent with citizens' water sampling activities. Results showed there were significant relations between lake users perceptions of physical condition of water and associated lake trophic state water chemistry variables. There were also significant relations between lake users perceptions of recreational and aesthetic enjoyment of water and associated lake trophic state water chemistry variables. While the relations reported in this study were significant there was also a lot of variance in actual water chemistry for any perceived water quality. Some of this variance was attributed to regional differences in perceptions of water quality. Before this type of survey is used for lake management activities in Florida, it is recommended to expand the number of individuals surveyed per lake, especially from multiple lake users to better understand the variance in water chemistry around perceived water quality. It is also recommended to add questions pertaining to additional lake uses including activities like fishing, bird watching and other wildlife related uses. Keywords: lake user survey; citizen monitoring; lake trophic state View Full Text ArticleSubscribe Affiliation: a Department of Fisheries and Aquatic Sciences, University of Florida Gainesville, Gainesville, FL, USA DOI: 10.1080/07438140409354247 Published in: Lake and Reservoir Management, Volume 20, Issue 3 September 2004 , pages 240 - 248 Publication Frequency: 4 issues per year First Published on: 01 September 2004 Formats available: PDF (English) | A lake user survey was conducted on 116 Florida lakes concurrent with citizens' water sampling activities. Results showed there were significant relations between lake users perceptions of physical condition of water and associated lake trophic state water chemistry variables. There were also significant relations between lake users perceptions of recreational and aesthetic enjoyment of water and associated lake trophic state water chemistry variables. While the relations reported in this study were significant there was also a lot of variance in actual water chemistry for any perceived water quality. Some of this variance was attributed to regional differences in perceptions of water quality. Before this type of survey is used for lake management activities in Florida, it is recommended to expand the number of individuals surveyed per lake, especially from multiple lake users to better understand the variance in water chemistry around perceived water quality. It is also recommended to add questions pertaining to additional lake uses including activities like fishing, bird watching and other wildlife related uses. |
| A Comparison of Fish and Aquatic Plant Assemblages to Assess Ecological Health of Small Wisconsin Lakes | Gene R. Hatzenbeler; Jeffrey M. Kampa; Martin J. Jennings; Edward E. Emmons | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 3 | 2004 | 211 - 218 | A Comparison of Fish and Aquatic Plant Assemblages to Assess Ecological Health of Small Wisconsin Lakes Authors: Gene R. Hatzenbelera; Jeffrey M. Kampaa; Martin J. Jenningsa; Edward E. Emmonsb Abstract Biological monitoring uses assemblage structure to assess condition of ecological systems. Taxa that effectively integrate impacts within the system of interest are useful for biological monitoring, whereas taxa that do not demonstrate predictable responses can provide ambiguous or misleading indicators. We compared the effectiveness of aquatic plant and fish assemblages for biological monitoring in 16 small lakes (< 80 ha). The lakes were limnologically similar but differed in extent of lakeshore development and type of watershed land-cover. Linear regression analysis revealed that the quality of the aquatic plant community declined with increasing lakeshore development (number of dwellings per km of shoreline), which is the primary source of impacts within this group of northern Wisconsin lakes. As lakeshore development increased, we observed a decrease in the Floristic Quality Index (FQI) of a lake, number of plant species per lake, number of highly intolerant plant species per lake, and the species richness and frequency of occurrence of floating vegetation. Conversely, fish species richness, centrarchid species richness, number of small benthic fish species, intolerant fish species richness and the proportion of the total catch of intolerant and vegetative-dwelling fish were not related to lakeshore development. These results indicate that, within the range of conditions observed, aquatic plant communities are more sensitive to lakeshore development than fish communities. Neither aquatic plant species composition nor fish assemblage variables were correlated with watershed land cover types; however all the watersheds were relatively small and undisturbed. In small lakes with few fish species, aquatic plants can be used as biological indicators for monitoring ecological conditions. Keywords: monitoring; lakes; fish; aquatic plants; development; land-cover; FQI; IBI View Full Text ArticleSubscribe Affiliations: a Wisconsin Department of Natural Resources, Bureau of Integrated Science Services, Spooner, WI b Wisconsin Department of Natural Resources, Bureau of Integrated Science Services, Monona, WI DOI: 10.1080/07438140409354245 Published in: Lake and Reservoir Management, Volume 20, Issue 3 September 2004 , pages 211 - 218 Publication Frequency: 4 issues per year First Published on: 01 September 2004 Formats available: PDF (English) | Biological monitoring uses assemblage structure to assess condition of ecological systems. Taxa that effectively integrate impacts within the system of interest are useful for biological monitoring, whereas taxa that do not demonstrate predictable responses can provide ambiguous or misleading indicators. We compared the effectiveness of aquatic plant and fish assemblages for biological monitoring in 16 small lakes (< 80 ha). The lakes were limnologically similar but differed in extent of lakeshore development and type of watershed land-cover. Linear regression analysis revealed that the quality of the aquatic plant community declined with increasing lakeshore development (number of dwellings per km of shoreline), which is the primary source of impacts within this group of northern Wisconsin lakes. As lakeshore development increased, we observed a decrease in the Floristic Quality Index (FQI) of a lake, number of plant species per lake, number of highly intolerant plant species per lake, and the species richness and frequency of occurrence of floating vegetation. Conversely, fish species richness, centrarchid species richness, number of small benthic fish species, intolerant fish species richness and the proportion of the total catch of intolerant and vegetative-dwelling fish were not related to lakeshore development. These results indicate that, within the range of conditions observed, aquatic plant communities are more sensitive to lakeshore development than fish communities. Neither aquatic plant species composition nor fish assemblage variables were correlated with watershed land cover types; however all the watersheds were relatively small and undisturbed. In small lakes with few fish species, aquatic plants can be used as biological indicators for monitoring ecological conditions. |
| Impacts of Metal Salt Addition on the Chemistry of Lake Elsinore, California: 1. Alum | Michael A. Anderson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 3 | 2004 | 249 - 258 | Impacts of Metal Salt Addition on the Chemistry of Lake Elsinore, California: 1. Alum Author: Michael A. Andersona Abstract A series of laboratory studies were conducted to evaluate the impacts of alum addition on the water chemistry of Lake Elsinore. Lake Elsinore is a warm, shallow, polymictic and eutrophic lake, located in southwest Riverside County in Southern California, that is plagued with chronic poor water quality conditions due in part to large internal nutrient loadings. The lake also possesses a high pH and high alkalinity. Control of internal phosphorus loading by alum was considered as a possible control method, although most alum applications have been made in relatively soft water lakes. The changes in water chemistry resulting from alum and high-acid alum treatments were quantified for 3 different Al doses (9, 13 and 18 mg L-1). The high alkalinity in the lake limited the capacity for alum at the 9 mg L-1 Al dose to reduce the equilibrium pH below 8.7. High acid alum formulations and higher Al doses were somewhat more successful at lowering the pH, however. For example, Al doses of 9 mg L-1+20% H2SO4 and 18 mg L-1 (no free acid) were able to lower the pH to approximately 8.5. The highest dose and free-acid content (18 mg L-1+20% H2SO4) was most effective, lowering the pH to about 8. Dissolved Al concentrations varied strongly as a function of Al dose, percent free acid in the high-acid alum formulations, and time. Dissolved Al concentrations increased with increasing pH, and approached (or exceeded) 2 mg L-1 in some samples, but generally remained below levels predicted by the solubility of amorphous Al(OH)3. pH and dissolved Al concentrations both varied markedly over time, due to kinetic limitations to CO2 outgassing. Dissolved Al concentrations monitored in longer-term core experiments decreased over time, suggesting transformation of amorphous, high-solubility Al phase(s) to more crystalline, lower-solubility phases. The high Al solubility and potential toxicity makes alum treatment inappropriate for Lake Elsinore and other strongly alkaline lakes. Keywords: alum; chemistry; Lake Elsinore View Full Text ArticleSubscribe Affiliation: a Department of Environmental Sciences, University of California, Riverside, CA DOI: 10.1080/07438140409354248 Published in: Lake and Reservoir Management, Volume 20, Issue 3 September 2004 , pages 249 - 258 Publication Frequency: 4 issues per year First Published on: 01 September 2004 Formats available: PDF (English) | A series of laboratory studies were conducted to evaluate the impacts of alum addition on the water chemistry of Lake Elsinore. Lake Elsinore is a warm, shallow, polymictic and eutrophic lake, located in southwest Riverside County in Southern California, that is plagued with chronic poor water quality conditions due in part to large internal nutrient loadings. The lake also possesses a high pH and high alkalinity. Control of internal phosphorus loading by alum was considered as a possible control method, although most alum applications have been made in relatively soft water lakes. The changes in water chemistry resulting from alum and high-acid alum treatments were quantified for 3 different Al doses (9, 13 and 18 mg L-1). The high alkalinity in the lake limited the capacity for alum at the 9 mg L-1 Al dose to reduce the equilibrium pH below 8.7. High acid alum formulations and higher Al doses were somewhat more successful at lowering the pH, however. For example, Al doses of 9 mg L-1+20% H2SO4 and 18 mg L-1 (no free acid) were able to lower the pH to approximately 8.5. The highest dose and free-acid content (18 mg L-1+20% H2SO4) was most effective, lowering the pH to about 8. Dissolved Al concentrations varied strongly as a function of Al dose, percent free acid in the high-acid alum formulations, and time. Dissolved Al concentrations increased with increasing pH, and approached (or exceeded) 2 mg L-1 in some samples, but generally remained below levels predicted by the solubility of amorphous Al(OH)3. pH and dissolved Al concentrations both varied markedly over time, due to kinetic limitations to CO2 outgassing. Dissolved Al concentrations monitored in longer-term core experiments decreased over time, suggesting transformation of amorphous, high-solubility Al phase(s) to more crystalline, lower-solubility phases. The high Al solubility and potential toxicity makes alum treatment inappropriate for Lake Elsinore and other strongly alkaline lakes. |
| Impacts, Perceptions, and Management of Shoreline Hazards and Water Levels on a Fluctuating Reservoir: A Case Study of the Winnebago System, Wisconsin | Anthony O. Gabriel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 3 | 2004 | 197 - 210 | Impacts, Perceptions, and Management of Shoreline Hazards and Water Levels on a Fluctuating Reservoir: A Case Study of the Winnebago System, Wisconsin Author: Anthony O. Gabriela Abstract This paper provides the results of a mail survey of 872 residential property owners along the shorelines of the Winnebago System, Wisconsin that determined their hazard experiences, adjustments, and management preferences in regards to fluctuating water levels. While half of the respondents were aware of hazard potentials prior to purchase, properties have been impacted by a range of shoreline hazards from flooding (27%) to high water levels (54%). Principally caused by a combination of storm-driven waves and high water levels, hazard damages are hazard-specific, and tend to relate to either the shoreline directly (e.g. loss of beach, lawn and garden damage) or to structures directly on the shoreline (e.g. shore protection or docks). Similar to other systems, many residents have resorted to structural hazard adjustments, generally as a response to erosion or high water levels. The majority of property owners indicated a preference for water level regulation to reduce shoreline hazards. However, the majority of respondents also would prefer the water levels to remain the same, while the remaining respondents were extremely divided between the various options for target summer and winter water levels, actually preferring levels that would increase hazard potentials. There is a need for a public education program on the Winne bago System that focuses on publicizing the technical limitations of lake level regulation to reduce hazard losses, the range of alternative hazard adjustment strategies, and the financial and technical assistance for hazard management available from various government agencies. Keywords: reservoir; hazard; erosion; flooding; water levels; management; Wisconsin; perception View Full Text ArticleSubscribe Affiliation: a Department of Geography and Land Studies, Central Washington University, Ellensburg, WA DOI: 10.1080/07438140409354244 Published in: Lake and Reservoir Management, Volume 20, Issue 3 September 2004 , pages 197 - 210 Publication Frequency: 4 issues per year First Published on: 01 September 2004 Formats available: PDF (English) | This paper provides the results of a mail survey of 872 residential property owners along the shorelines of the Winnebago System, Wisconsin that determined their hazard experiences, adjustments, and management preferences in regards to fluctuating water levels. While half of the respondents were aware of hazard potentials prior to purchase, properties have been impacted by a range of shoreline hazards from flooding (27%) to high water levels (54%). Principally caused by a combination of storm-driven waves and high water levels, hazard damages are hazard-specific, and tend to relate to either the shoreline directly (e.g. loss of beach, lawn and garden damage) or to structures directly on the shoreline (e.g. shore protection or docks). Similar to other systems, many residents have resorted to structural hazard adjustments, generally as a response to erosion or high water levels. The majority of property owners indicated a preference for water level regulation to reduce shoreline hazards. However, the majority of respondents also would prefer the water levels to remain the same, while the remaining respondents were extremely divided between the various options for target summer and winter water levels, actually preferring levels that would increase hazard potentials. There is a need for a public education program on the Winne bago System that focuses on publicizing the technical limitations of lake level regulation to reduce hazard losses, the range of alternative hazard adjustment strategies, and the financial and technical assistance for hazard management available from various government agencies. |
| Fish Assemblages of Reservoirs, Illustrated by Lake Texoma (Oklahoma-Texas, USA) as a Representative System | William J. Matthews; Keith B. Gido; Frances P. Gelwick | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 3 | 2004 | 219 - 239 | Fish Assemblages of Reservoirs, Illustrated by Lake Texoma (Oklahoma-Texas, USA) as a Representative System Authors: William J. Matthewsa; Keith B. Gidob; Frances P. Gelwickc Abstract We suggest six generalizations about the ecology of fishes of large, warm, reservoirs in the southern United States. We test these postulates with examples from more than 20 years of our studies in Lake Texoma (Oklahoma-Texas), and previous historic work in this impoundment. Such impoundments are dynamic systems in which precise predictions about fish faunas, local assemblages, or their potential effects in river-reservoir ecosystems are difficult. However, several generalizations can be supported: (1) fish faunas in reservoirs are a largely non-coevolved array of species, consisting of native and non-native species that may remain relatively unchanged for decades; (2) the fish fauna of a reservoir changes in response to introduction of some non-native species but not others; (3) The fish fauna of a reservoir can change in response to abiotic events that occur at a range of spatial and temporal scales, but effects may be inconsistent and transitory; (4) strong abiotic and biotic gradients in reservoirs influence fish distribution from uplake to downlake and from shallow to deep habitats; (5) Predictability of local fish assemblage structure in reservoirs is low and can vary between littoral and open-water zones; (6) Effects of fish on ecology of the reservoir relates to trophic groups represented, and to numbers of omnivorous fish. Keywords: reservoirs; fishes; fish assemblages; fish faunas; fish distribution; abiotic events; disturbance; long-term changes View Full Text ArticleSubscribe Affiliations: a Department of Zoology and Biological Station, University of Oklahoma, Norman, OK b Division of Biology, Kansas State University, Manhattan, KS c Department of Wildlife and Fisheries Science, Texas A&M University, College Station, TX DOI: 10.1080/07438140409354246 Published in: Lake and Reservoir Management, Volume 20, Issue 3 September 2004 , pages 219 - 239 Publication Frequency: 4 issues per year First Published on: 01 September 2004 Formats available: PDF (English) | We suggest six generalizations about the ecology of fishes of large, warm, reservoirs in the southern United States. We test these postulates with examples from more than 20 years of our studies in Lake Texoma (Oklahoma-Texas), and previous historic work in this impoundment. Such impoundments are dynamic systems in which precise predictions about fish faunas, local assemblages, or their potential effects in river-reservoir ecosystems are difficult. However, several generalizations can be supported: (1) fish faunas in reservoirs are a largely non-coevolved array of species, consisting of native and non-native species that may remain relatively unchanged for decades; (2) the fish fauna of a reservoir changes in response to introduction of some non-native species but not others; (3) The fish fauna of a reservoir can change in response to abiotic events that occur at a range of spatial and temporal scales, but effects may be inconsistent and transitory; (4) strong abiotic and biotic gradients in reservoirs influence fish distribution from uplake to downlake and from shallow to deep habitats; (5) Predictability of local fish assemblage structure in reservoirs is low and can vary between littoral and open-water zones; (6) Effects of fish on ecology of the reservoir relates to trophic groups represented, and to numbers of omnivorous fish. |
| Nutrient Patterns in a Mainstem Reservoir, Kentucky Lake, USA, Over a 10-year Period | P. M. Yurista; D. S. White; G. W. Kipphut; K. Johnston; G. Rice; S. P. Hendricks | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 2 | 2004 | 148 - 163 | Nutrient Patterns in a Mainstem Reservoir, Kentucky Lake, USA, Over a 10-year Period Authors: P. M. Yuristaa; D. S. Whiteb; G. W. Kipphutb; K. Johnstonb; G. Riceb; S. P. Hendricksb Abstract Nutrient patterns were examined spatially and temporally from 1989 to 1998 in Kentucky Lake U.S.A., the largest mainstem reservoir on the Tennessee River system. Nutrients included NO3--N, NH4+-N, PO4-, SiO2, SO4-2, and Cl-. Seasonal patterns in most nutrient concentrations were described well by cosine functions. Seasonal descriptions had less variance than discharge related descriptions of nutrient concentrations, possibly due to regulation of reservoir discharge. Differing land-use practices on either side of the reservoir were associated with significantly different nutrient concentrations in their related embayments. The agriculturally dominated western side embayments had lower nutrient concentrations than either the forested eastern side of the reservoir or mainstem sites. Annual average nutrient concentrations did not vary greatly over the 10-year period, indicating no change in eutrophication potential during the sampling period. An exception was a significant decline in SO4-2 levels from 23 mg·L-1 in 1992 to 12.8 mg·L-1 in 1998. Annual export of nutrients was computed from yearly regressions on seasonal concentrations and daily discharge rates. Keywords: reservoirs; nutrients; nutrient cycles; ecological variation; spatial variation; Kentucky Lake; Tennessee River View Full Text ArticleSubscribe Affiliations: a U.S. EPA (MED), Duluth, MN, U.S.A. b Hancock Biological Station, Murray State University, Murray, KY, U.S.A. DOI: 10.1080/07438140409354359 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 June 2004 Formats available: PDF (English) | Nutrient patterns were examined spatially and temporally from 1989 to 1998 in Kentucky Lake U.S.A., the largest mainstem reservoir on the Tennessee River system. Nutrients included NO3--N, NH4+-N, PO4-, SiO2, SO4-2, and Cl-. Seasonal patterns in most nutrient concentrations were described well by cosine functions. Seasonal descriptions had less variance than discharge related descriptions of nutrient concentrations, possibly due to regulation of reservoir discharge. Differing land-use practices on either side of the reservoir were associated with significantly different nutrient concentrations in their related embayments. The agriculturally dominated western side embayments had lower nutrient concentrations than either the forested eastern side of the reservoir or mainstem sites. Annual average nutrient concentrations did not vary greatly over the 10-year period, indicating no change in eutrophication potential during the sampling period. An exception was a significant decline in SO4-2 levels from 23 mg·L-1 in 1992 to 12.8 mg·L-1 in 1998. Annual export of nutrients was computed from yearly regressions on seasonal concentrations and daily discharge rates. |
| Assessing Historical Bathymetry: Kingsmere Lake Revisited | Guy E. Melville; Jonathan K. Melville | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 2 | 2004 | 141 - 147 | Assessing Historical Bathymetry: Kingsmere Lake Revisited Authors: Guy E. Melvillea; Jonathan K. Melvilleb Abstract Surveys carried out prior to 1950 still constitute our knowledge base for many lakes, particularly those without road access in more remote locations. We assess the accuracy of historical bathymetric data using Kingsmere Lake (Rawson 1936), Prince Albert National Park of Canada, as an example. Rawson presented depth-specific attributes as percents only, which have since formed the basis for management of the lake. In this study, new depths, all spatially referenced, were acquired by sounders along transects. In comparison to Rawson's work, the new areas differ by up to fifty percent because the methods used previously were much less accurate. Volumetric indices are much more similar; the depth-percent volume curves are the same. In using historical data, numerical correction factors for lake areas would probably yield accurate subsurface indices for most lakes. The updated bathymetry for Kingsmere Lake will aid in the determination of Total Allowable Catch for exploited fish species. The bathymetry will also help with watershed activities such as fire management, which affect nutrient loading and ultimately oxygen conditions in the lake. Modern surveys represent the ideal approach, especially for lakes like the MacKenzie Great Lakes. When such studies might occur is uncertain. Rawson, D. S. 1936. J. Biol. Bd. Can. 2:227-284. Keywords: bathymetry; historical data; areal-correction; updated science View Full Text ArticleSubscribe Affiliations: a Aquatic Ecosystems Section, Saskatchewan Research Council and Division of Environmental Engineering, University of Saskatchewan, Saskatoon, SK, Canada b Physical Geography Program, University of Saskatchewan, Saskatoon, SK, Canada DOI: 10.1080/07438140409354358 Published in: Lake and Reservoir Management, Volume 20, Issue 2 June 2004 , pages 141 - 147 Publication Frequency: 4 issues per year First Published on: 01 June 2004 Formats available: PDF (English) | Surveys carried out prior to 1950 still constitute our knowledge base for many lakes, particularly those without road access in more remote locations. We assess the accuracy of historical bathymetric data using Kingsmere Lake (Rawson 1936), Prince Albert National Park of Canada, as an example. Rawson presented depth-specific attributes as percents only, which have since formed the basis for management of the lake. In this study, new depths, all spatially referenced, were acquired by sounders along transects. In comparison to Rawson's work, the new areas differ by up to fifty percent because the methods used previously were much less accurate. Volumetric indices are much more similar; the depth-percent volume curves are the same. In using historical data, numerical correction factors for lake areas would probably yield accurate subsurface indices for most lakes. The updated bathymetry for Kingsmere Lake will aid in the determination of Total Allowable Catch for exploited fish species. The bathymetry will also help with watershed activities such as fire management, which affect nutrient loading and ultimately oxygen conditions in the lake. Modern surveys represent the ideal approach, especially for lakes like the MacKenzie Great Lakes. When such studies might occur is uncertain. Rawson, D. S. 1936. J. Biol. Bd. Can. 2:227-284. |
| Book Review | James J. Sartoris | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 2 | 2004 | 175 | Book Review Author: James J. Sartorisa View Full Text ArticleSubscribe Affiliation: a Biological Resources Division, U.S. Geological Survey, Denver, Colorado, USA DOI: 10.1080/07438140409354361 Published in: Lake and Reservoir Management, Volume 20, Issue 2 June 2004 , page 175 Publication Frequency: 4 issues per year First Published on: 01 June 2004 Formats available: PDF (English) | |
| Gasoline-Related Organics in Lake Tahoe Before and After Prohibition of Carbureted Two-Stroke Engines | Michael S. Lico | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 2 | 2004 | 164 - 174 | Gasoline-Related Organics in Lake Tahoe Before and After Prohibition of Carbureted Two-Stroke Engines Author: Michael S. Licoa Abstract On June 1, 1999, carbureted two-stroke engines were banned on waters within the Lake Tahoe Basin of California and Nevada. The main gasoline components MTBE (methyl tert-butyl ether) and BTEX (benzene, toluene, ethylbenzene, and xylenes) were present at detectable concentrations in all samples taken from Lake Tahoe during 1997-98 prior to the ban. Samples taken from 1999 through 2001 after the ban contained between 10 and 60 percent of the pre-ban concentrations of these compounds, with MTBE exhibiting the most dramatic change (a 90 percent decrease). MTBE and BTEX concentrations in water samples from Lake Tahoe and Lower Echo Lake were related to the amount of boat use at the sampling sites. Polycyclic aromatic hydrocarbon (PAH) compounds are produced by high-temperature pyrolytic reactions. They were sampled using semipermeable membrane sampling devices in Lake Tahoe and nearby Donner Lake, where carbureted two-stroke engines are legal. PAHs were detected in all samples taken from Lake Tahoe and Donner Lake. The number of PAH compounds and their concentrations are related to boat use. The highest concentrations of PAH were detected in samples from two heavily used boating areas, Tahoe Keys Marina and Donner Lake boat ramp. Other sources of PAH, such as atmospheric deposition, wood smoke, tributary streams, and automobile exhaust do not contribute large amounts of PAH to Lake Tahoe. Similar numbers of PAH compounds and concentrations were found in Lake Tahoe before and after the ban of carbureted two-stroke engines. Keywords: BTEX; MTBE; PAH; two-stroke engines; Lake Tahoe; gasoline View Full Text ArticleSubscribe Affiliation: a United States Geological Survey, Carson City, NV, USA DOI: 10.1080/07438140409354360 Published in: Lake and Reservoir Management, Volume 20, Issue 2 June 2004 , pages 164 - 174 Publication Frequency: 4 issues per year First Published on: 01 June 2004 Formats available: PDF (English) | On June 1, 1999, carbureted two-stroke engines were banned on waters within the Lake Tahoe Basin of California and Nevada. The main gasoline components MTBE (methyl tert-butyl ether) and BTEX (benzene, toluene, ethylbenzene, and xylenes) were present at detectable concentrations in all samples taken from Lake Tahoe during 1997-98 prior to the ban. Samples taken from 1999 through 2001 after the ban contained between 10 and 60 percent of the pre-ban concentrations of these compounds, with MTBE exhibiting the most dramatic change (a 90 percent decrease). MTBE and BTEX concentrations in water samples from Lake Tahoe and Lower Echo Lake were related to the amount of boat use at the sampling sites. Polycyclic aromatic hydrocarbon (PAH) compounds are produced by high-temperature pyrolytic reactions. They were sampled using semipermeable membrane sampling devices in Lake Tahoe and nearby Donner Lake, where carbureted two-stroke engines are legal. PAHs were detected in all samples taken from Lake Tahoe and Donner Lake. The number of PAH compounds and their concentrations are related to boat use. The highest concentrations of PAH were detected in samples from two heavily used boating areas, Tahoe Keys Marina and Donner Lake boat ramp. Other sources of PAH, such as atmospheric deposition, wood smoke, tributary streams, and automobile exhaust do not contribute large amounts of PAH to Lake Tahoe. Similar numbers of PAH compounds and concentrations were found in Lake Tahoe before and after the ban of carbureted two-stroke engines. |
| Use of Transparency Tubes for Rapid Assessment of Total Suspended Solids and Turbidity in Streams | Paul Anderson; Robert D. Davie | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 2 | 2004 | 110 - 120 | Use of Transparency Tubes for Rapid Assessment of Total Suspended Solids and Turbidity in Streams Authors: Paul Andersona; Robert D. Daviea Abstract Studies were conducted to evaluate the use of transparency tubes to predict total suspended solids concentrations (TSS) and NTU turbidity in streams. Linear regression of data collected from 29 sample stations (12 streams) in northeast Ohio revealed a highly predictive correlation for both parameters using the Ohio Sediment Sticko. Laboratory studies showed significant differences between water clarity readings among individual observers using the Ohio Sediment Sticko. The type of visual end point target used in the tube had no effect on water clarity readings. A table to predict TSS concentrations based upon water clarity was developed for the Ohio Sediment Sticko. A comparison of three tubes of differing design (e.g., Minnesota Pollution Control Agency tube, NOAA GLOBE tube, and Ohio Sediment Sticko) found no significant differences in the relationship of water clarity measurement vs. TSS concentrations or NTU turbidity among tubes. Our data indicate that predictive equations developed for the Ohio Sediment Sticko can be applied with statistical confidence to both the MPCA tube and the NOAA GLOBE tube. When appropriately used, transparency tubes can be an effective and inexpensive monitoring tool to estimate relative sediment loads to lakes from different watersheds. Keywords: transparency tube; NTU turbidity; non-point pollution; total suspended solids; volunteer monitoring; streams; Ohio Sediment Sticko; MPCA tube; NOAA GLOBE tube View Full Text ArticleSubscribe Affiliation: a Division of Surface Water, Ohio Environmental Protection Agency, Twinsburg, OH DOI: 10.1080/07438140409354355 Published in: Lake and Reservoir Management, Volume 20, Issue 2 June 2004 , pages 110 - 120 Publication Frequency: 4 issues per year First Published on: 01 June 2004 Formats available: PDF (English) | Studies were conducted to evaluate the use of transparency tubes to predict total suspended solids concentrations (TSS) and NTU turbidity in streams. Linear regression of data collected from 29 sample stations (12 streams) in northeast Ohio revealed a highly predictive correlation for both parameters using the Ohio Sediment Sticko. Laboratory studies showed significant differences between water clarity readings among individual observers using the Ohio Sediment Sticko. The type of visual end point target used in the tube had no effect on water clarity readings. A table to predict TSS concentrations based upon water clarity was developed for the Ohio Sediment Sticko. A comparison of three tubes of differing design (e.g., Minnesota Pollution Control Agency tube, NOAA GLOBE tube, and Ohio Sediment Sticko) found no significant differences in the relationship of water clarity measurement vs. TSS concentrations or NTU turbidity among tubes. Our data indicate that predictive equations developed for the Ohio Sediment Sticko can be applied with statistical confidence to both the MPCA tube and the NOAA GLOBE tube. When appropriately used, transparency tubes can be an effective and inexpensive monitoring tool to estimate relative sediment loads to lakes from different watersheds. |
| Effects of Water Level Fluctuation and Short-Term Climate Variation on Thermal and Stratification Regimes of a British Columbia Reservoir and Lake | Weston H. Nowlin; John-Mark Davies; Rick N. Nordin; Asit Mazumder | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 2 | 2004 | 91 - 109 | Effects of Water Level Fluctuation and Short-Term Climate Variation on Thermal and Stratification Regimes of a British Columbia Reservoir and Lake Authors: Weston H. Nowlina; John-Mark Daviesa; Rick N. Nordina; Asit Mazumdera Abstract Stratification and thermal regimes of a reservoir with fluctuating water levels were compared to a natural lake of similar morphometry and trophic status over a two-year period (2000-2001) in coastal British Columbia, Canada. We compared the timing and duration of stratification, summer heat budgets and heat fluxes in two morphometrically contrasting basins of Sooke Lake Reservoir and Shawnigan Lake (one shallow and one deep basin per water body). In the second year of the study, a 100-year drought allowed us to compare responses of a reservoir and a lake to contrasting years of climatic conditions. Loss of volume from the reservoir during summer and fall caused stratification and thermal regimes to differ from Shawnigan Lake, but the magnitude of these differences was mediated by basin morphometry. Duration of summer stratification, timing of heat content, and the relative importance of seasonal heat fluxes in the shallow basin of Sooke Lake Reservoir were most different from Shawnigan Lake. While there were no major differences between years for Shawnigan Lake, contrasting years in precipitation and hydrology caused Sooke Lake Reservoir stratification and thermal regimes to differ between years. The magnitude of differences between years was mediated by basin size, with the shallower reservoir basin having greater differences between years. Our results indicate that reservoir physical processes are sensitive to short-term changes in hydrology, and that the combined impacts of short-term climate variation and anthropogenic manipulation of hydrology may be greater in shallow reservoir ecosystems. Keywords: reservoir limnology; drawdown; heat budget; climate variability; stratification; thermal regimes; mixing regimes View Full Text ArticleSubscribe Affiliation: a Centre for Water and Watershed Research, Department of Biology, University of Victoria, Victoria, British Columbia, Canada DOI: 10.1080/07438140409354354 Published in: Lake and Reservoir Management, Volume 20, Issue 2 June 2004 , pages 91 - 109 Publication Frequency: 4 issues per year First Published on: 01 June 2004 Formats available: PDF (English) | Stratification and thermal regimes of a reservoir with fluctuating water levels were compared to a natural lake of similar morphometry and trophic status over a two-year period (2000-2001) in coastal British Columbia, Canada. We compared the timing and duration of stratification, summer heat budgets and heat fluxes in two morphometrically contrasting basins of Sooke Lake Reservoir and Shawnigan Lake (one shallow and one deep basin per water body). In the second year of the study, a 100-year drought allowed us to compare responses of a reservoir and a lake to contrasting years of climatic conditions. Loss of volume from the reservoir during summer and fall caused stratification and thermal regimes to differ from Shawnigan Lake, but the magnitude of these differences was mediated by basin morphometry. Duration of summer stratification, timing of heat content, and the relative importance of seasonal heat fluxes in the shallow basin of Sooke Lake Reservoir were most different from Shawnigan Lake. While there were no major differences between years for Shawnigan Lake, contrasting years in precipitation and hydrology caused Sooke Lake Reservoir stratification and thermal regimes to differ between years. The magnitude of differences between years was mediated by basin size, with the shallower reservoir basin having greater differences between years. Our results indicate that reservoir physical processes are sensitive to short-term changes in hydrology, and that the combined impacts of short-term climate variation and anthropogenic manipulation of hydrology may be greater in shallow reservoir ecosystems. |
| Temporal and Vertical Variability in the Relationship Among Organic Matter Indices in a Deep Reservoir Ecosystem | Kwangsoon Choi; Bomchul Kim; Ju-Hyun Park; Yoon-Hee Kim; Mansig Jun | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 2 | 2004 | 130 - 140 | Temporal and Vertical Variability in the Relationship Among Organic Matter Indices in a Deep Reservoir Ecosystem Authors: Kwangsoon Choia; Bomchul Kima; Ju-Hyun Parka; Yoon-Hee Kima; Mansig Juna Abstract Temporal and vertical variability in the relationship between biochemical oxygen demand (BOD), chemical oxygen demand (CODMn), and total organic carbon (TOC) were investigated in a deep reservoir (Lake Soyang, Korea) and compared with other major reservoirs in Korea. The average oxidation efficiencies of BOD and COD were low (16% and 36%, respectively), compared with TOC analysis. Weakly positive correlations could be observed between TOC vs. BOD (r = 0.64) and TOC vs. CODMn (r = 0.66) in the upper layer, whereas significant correlations were not observed in the middle and deep layers of the water column. In the upper layer, CODMn was more strongly correlated with particulate organic carbon (POC) than with dissolved organic carbon (DOC), even though DOC is ten times more abundant than POC. This might imply that DOC in the lake is more resistant to permanganate oxidation than POC. The oxidation efficiency of BOD, an indicator of biodegradability, varied among water layers (upper > deep > middle layer). The lower efficiency in the middle layer may be due to an input of recalcitrant allochthonous organic matter during the summer monsoon, when water is known to flow into this layer of the lake. The oxidation efficiency of CODMn also varied significantly by water layer (upper ≅ middle > deep layer). Because of poor and variable oxidation efficiencies, BOD and CODMn measured at any particular time or location should be used with caution as indices of organic matter content in lakes. Keywords: BOD; COD; TOC; oxidation efficiency; variation View Full Text ArticleSubscribe Affiliation: a Department of Environmental Science, Kangwon National University, Chunchon, South Korea DOI: 10.1080/07438140409354357 Published in: Lake and Reservoir Management, Volume 20, Issue 2 June 2004 , pages 130 - 140 Publication Frequency: 4 issues per year First Published on: 01 June 2004 Formats available: PDF (English) | Temporal and vertical variability in the relationship between biochemical oxygen demand (BOD), chemical oxygen demand (CODMn), and total organic carbon (TOC) were investigated in a deep reservoir (Lake Soyang, Korea) and compared with other major reservoirs in Korea. The average oxidation efficiencies of BOD and COD were low (16% and 36%, respectively), compared with TOC analysis. Weakly positive correlations could be observed between TOC vs. BOD (r = 0.64) and TOC vs. CODMn (r = 0.66) in the upper layer, whereas significant correlations were not observed in the middle and deep layers of the water column. In the upper layer, CODMn was more strongly correlated with particulate organic carbon (POC) than with dissolved organic carbon (DOC), even though DOC is ten times more abundant than POC. This might imply that DOC in the lake is more resistant to permanganate oxidation than POC. The oxidation efficiency of BOD, an indicator of biodegradability, varied among water layers (upper > deep > middle layer). The lower efficiency in the middle layer may be due to an input of recalcitrant allochthonous organic matter during the summer monsoon, when water is known to flow into this layer of the lake. The oxidation efficiency of CODMn also varied significantly by water layer (upper ≅ middle > deep layer). Because of poor and variable oxidation efficiencies, BOD and CODMn measured at any particular time or location should be used with caution as indices of organic matter content in lakes. |
| Augmentation of a Long-term Monitoring Program for Lake George, NY by Citizen Volunteers | Charles W. Boylen; Eric A. Howe; Jeffrey S. Bartkowski; Lawrence W. Eichler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 2 | 2004 | 121 - 129 | Augmentation of a Long-term Monitoring Program for Lake George, NY by Citizen Volunteers Authors: Charles W. Boylena; Eric A. Howea; Jeffrey S. Bartkowskia; Lawrence W. Eichlera Abstract Drinking water standards and recreational demands on lakes and ponded waters place a high priority on the management of water quality. As stakeholders, volunteer citizen monitors can provide considerable assistance to state agencies and research organizations charged with monitoring freshwater resources by accumulating valuable data for water quality evaluation and lake assessment. The Lay Monitoring Program on Lake George (NY) was initiated in 1980 concomitant with the establishment of a long-term chemical monitoring program. By 2002, 23 years of Secchi transparency and surface temperature data had been collected. Results have revealed potential relationships between variations in Secchi transparency and trophic indicators (chlorophyll a and total phosphorus) and have assisted in evaluating the potential influences of both increased recreational use and precipitation regime. Lay monitor participation provides a valuable and cost effective enhancement for ongoing lake chemical and biotic effect studies. The integration of lay monitor Secchi data improves the breadth and consistency of long-term datasets, thereby increasing the program effectiveness in detecting incremental changes in water quality. Keywords: volunteer; lay monitoring; Lake George; New York; Secchi; long-term lake monitoring View Full Text ArticleSubscribe Affiliation: a Darrin Fresh Water Institute, Rensselaer Polytechnic Institute, Bolton Landing, NY DOI: 10.1080/07438140409354356 Published in: Lake and Reservoir Management, Volume 20, Issue 2 June 2004 , pages 121 - 129 Publication Frequency: 4 issues per year First Published on: 01 June 2004 Formats available: PDF (English) | Drinking water standards and recreational demands on lakes and ponded waters place a high priority on the management of water quality. As stakeholders, volunteer citizen monitors can provide considerable assistance to state agencies and research organizations charged with monitoring freshwater resources by accumulating valuable data for water quality evaluation and lake assessment. The Lay Monitoring Program on Lake George (NY) was initiated in 1980 concomitant with the establishment of a long-term chemical monitoring program. By 2002, 23 years of Secchi transparency and surface temperature data had been collected. Results have revealed potential relationships between variations in Secchi transparency and trophic indicators (chlorophyll a and total phosphorus) and have assisted in evaluating the potential influences of both increased recreational use and precipitation regime. Lay monitor participation provides a valuable and cost effective enhancement for ongoing lake chemical and biotic effect studies. The integration of lay monitor Secchi data improves the breadth and consistency of long-term datasets, thereby increasing the program effectiveness in detecting incremental changes in water quality. |
| Spatial Distribution and Seasonal Dynamics of Plankton in a Terminal Multiple-Series Reservoir | John E. Havel; Kristen R. Pattinson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 1 | 2004 | 14 - 26 | Spatial Distribution and Seasonal Dynamics of Plankton in a Terminal Multiple-Series Reservoir Authors: John E. Havela; Kristen R. Pattinsona Abstract Despite several decades of research on eutrophication in lakes, changes in reservoir plankton communities are poorly understood. The current study examined spatial patterns and dynamics of algae and zooplankton in an oligo-mesotrophic main-stem reservoir, Bull Shoals Lake, Missouri-Arkansas, which is currently threatened from rapid development in upstream reservoirs. Eighteen sites were sampled during one week in summer and the seasonal dynamics of algae and zooplankton were followed at two of these sites. The lake showed strong spatial patterning in transparency, concentrations of phosphorus and chlorophyll-a, and densities of algae and zooplankton. Algal composition also varied substantially among sites, with cyanobacteria most abundant in up-reservoir and tributary sites. Although cyanobacteria were most abundant in late summer, appreciable densities were found throughout the year. Zooplankton were dominated by rotifers and cladocerans, which showed large oscillations in density over time. Abundance peaks occurred earlier in an up-reservoir than in a down-reservoir site, with a time delay of about a month for algae and four months for zooplankton. The plankton composition was consistent with the oligo-mesotrophic status of Bull Shoals Lake, but high densities of cyanobacteria at some tributary sites and in upstream reservoirs indicate localized enrichment and the threat of eutrophication in this clear Ozark lake. Keywords: Bull Shoals Lake; cyanobacteria; Daphnia; trophic interactions; zooplankton View Full Text ArticleSubscribe Affiliation: a Department of Biology, Southwest Missouri State University, Springfield, MO, USA DOI: 10.1080/07438140409354097 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 March 2004 Formats available: PDF (English) | Despite several decades of research on eutrophication in lakes, changes in reservoir plankton communities are poorly understood. The current study examined spatial patterns and dynamics of algae and zooplankton in an oligo-mesotrophic main-stem reservoir, Bull Shoals Lake, Missouri-Arkansas, which is currently threatened from rapid development in upstream reservoirs. Eighteen sites were sampled during one week in summer and the seasonal dynamics of algae and zooplankton were followed at two of these sites. The lake showed strong spatial patterning in transparency, concentrations of phosphorus and chlorophyll-a, and densities of algae and zooplankton. Algal composition also varied substantially among sites, with cyanobacteria most abundant in up-reservoir and tributary sites. Although cyanobacteria were most abundant in late summer, appreciable densities were found throughout the year. Zooplankton were dominated by rotifers and cladocerans, which showed large oscillations in density over time. Abundance peaks occurred earlier in an up-reservoir than in a down-reservoir site, with a time delay of about a month for algae and four months for zooplankton. The plankton composition was consistent with the oligo-mesotrophic status of Bull Shoals Lake, but high densities of cyanobacteria at some tributary sites and in upstream reservoirs indicate localized enrichment and the threat of eutrophication in this clear Ozark lake. |
| Influence of Water Level on Torpedograss Establishment in Lake Okeechobee, Florida | Dian H. Smith; R. Michael Smart; Charles G. Hanlon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 1 | 2004 | 1 - 13 | Influence of Water Level on Torpedograss Establishment in Lake Okeechobee, Florida Authors: Dian H. Smitha; R. Michael Smarta; Charles G. Hanlonb Abstract Lake Okeechobee, a 173,200 ha shallow subtropical lake located in south Florida, has been invaded recently by torpedograss (Panicum repens), an exotic, terrestrial species, that was intentionally introduced to Florida in the early 1900s. Since the 1970s, more than 6,000 ha of native plants, including spikerush (Eleocharis cellulose) and beakrush (Rhynchospora spp.) and open water habitat have been displaced by torpedograss in areas of the marsh where inundation depths often are less than 50 cm. The ability of torpedograss to disperse and become established at different water depths was evaluated in a series of experimental pond studies. These studies revealed that fragments remain buoyant for extended periods and so facilitate the dispersal of torpedograss within the lake. If fragments become anchored to sediment that is either exposed or in shallow water, they can readily root and establish mature plants. Once established, torpedograss can thrive in depths of 75 cm or less and can survive prolonged exposure to flooding depths greater than 1 m. In this manner, low water periods can contribute to the dispersal and colonization pattern of torpedograss in the lake. When coupled with lake elevation data, these findings suggest that low water levels or drawdowns would increase the marsh area susceptible to torpedograss invasion. Keywords: Panicum repens; torpedograss; stem fragment; rhizome; invasive species; Eleocharis cellulosa; Lake Okeechobee; hydrological effects; invasion View Full Text ArticleSubscribe Affiliations: a USAERDC Lewisville Aquatic Ecosystem Research Facility, Lewisville, Texas b Okeechobee Research Department, South Florida Water Management District, West Palm Beach, Florida DOI: 10.1080/07438140409354096 Published in: Lake and Reservoir Management, Volume 20, Issue 1 March 2004 , pages 1 - 13 Publication Frequency: 4 issues per year First Published on: 01 March 2004 Formats available: PDF (English) | Lake Okeechobee, a 173,200 ha shallow subtropical lake located in south Florida, has been invaded recently by torpedograss (Panicum repens), an exotic, terrestrial species, that was intentionally introduced to Florida in the early 1900s. Since the 1970s, more than 6,000 ha of native plants, including spikerush (Eleocharis cellulose) and beakrush (Rhynchospora spp.) and open water habitat have been displaced by torpedograss in areas of the marsh where inundation depths often are less than 50 cm. The ability of torpedograss to disperse and become established at different water depths was evaluated in a series of experimental pond studies. These studies revealed that fragments remain buoyant for extended periods and so facilitate the dispersal of torpedograss within the lake. If fragments become anchored to sediment that is either exposed or in shallow water, they can readily root and establish mature plants. Once established, torpedograss can thrive in depths of 75 cm or less and can survive prolonged exposure to flooding depths greater than 1 m. In this manner, low water periods can contribute to the dispersal and colonization pattern of torpedograss in the lake. When coupled with lake elevation data, these findings suggest that low water levels or drawdowns would increase the marsh area susceptible to torpedograss invasion. |
| Management Issues, Characteristics and Effectiveness of Lake Associations and Lake Districts in Wisconsin | Anthony O. Gabriel; Cynthia Lancaster | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 1 | 2004 | 27 - 38 | Management Issues, Characteristics and Effectiveness of Lake Associations and Lake Districts in Wisconsin Authors: Anthony O. Gabriela; Cynthia Lancasterb Abstract Through a state-wide survey, this paper compares the characteristics of lake associations and lake districts, including their management objectives, issues, activities, and use of funds and contacts. It also examines the relationships between reported management activities and effectiveness and the nature of the issues, lake characteristics, and organizational characteristics. Lake associations and districts have distinct goals and significant differences in the lake issues each finds important, their activities, and effectiveness. Overall, lake districts tend to initiate higher numbers of actions on important issues, while lake associations tend to report a significantly higher proportion of management actions effectively addressing those issues. Lake associations and districts also differ greatly in their sources of revenue and expenditures, with lake districts having significantly higher amounts in both. We found a positive correlation between the total number of lake management activities undertaken by lake management organizations and the number of cottages, percentage of permanent residents, and property values found on their lake, as well as their membership sizes and annual membership fees. The number of cottages and membership sizes were also significantly correlated with the number of management activities initiated, while the number of cottages was the only factor significantly correlated with the number of issues effectively addressed. We found that organizations affiliated with Wisconsin Association of Lakes are engaged insignificantly higher number of activities and effective solutions. In addition, significantly higher numbers of activities are undertaken by lake districts, as well as organizations that are incorporated and have written by-laws. Keywords: lake management; lake associations; lake districts; Wisconsin View Full Text ArticleSubscribe Affiliations: a Department of Geography and Land Studies, Central Washington University, Ellensburg, WA b Wisconsin Department of Natural Resources, Oshkosh, WI DOI: 10.1080/07438140409354098 Published in: Lake and Reservoir Management, Volume 20, Issue 1 March 2004 , pages 27 - 38 Publication Frequency: 4 issues per year First Published on: 01 March 2004 Formats available: PDF (English) | Through a state-wide survey, this paper compares the characteristics of lake associations and lake districts, including their management objectives, issues, activities, and use of funds and contacts. It also examines the relationships between reported management activities and effectiveness and the nature of the issues, lake characteristics, and organizational characteristics. Lake associations and districts have distinct goals and significant differences in the lake issues each finds important, their activities, and effectiveness. Overall, lake districts tend to initiate higher numbers of actions on important issues, while lake associations tend to report a significantly higher proportion of management actions effectively addressing those issues. Lake associations and districts also differ greatly in their sources of revenue and expenditures, with lake districts having significantly higher amounts in both. We found a positive correlation between the total number of lake management activities undertaken by lake management organizations and the number of cottages, percentage of permanent residents, and property values found on their lake, as well as their membership sizes and annual membership fees. The number of cottages and membership sizes were also significantly correlated with the number of management activities initiated, while the number of cottages was the only factor significantly correlated with the number of issues effectively addressed. We found that organizations affiliated with Wisconsin Association of Lakes are engaged insignificantly higher number of activities and effective solutions. In addition, significantly higher numbers of activities are undertaken by lake districts, as well as organizations that are incorporated and have written by-laws. |
| Improvement in Moses Lake Quality from Dilution and Sewage Diversion | Eugene B. Welch; Evan R. Weiher | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 1 | 2004 | 76 - 84 | Improvement in Moses Lake Quality from Dilution and Sewage Diversion Authors: Eugene B. Welcha; Evan R. Weihera Abstract Moses Lake has received dilution water in 9 of 10 years since treatment began in 1977. The average input for those years was 143 79 106 m3/yr over 93 days, which represents flushing rates of about 13 percent/day for Parker Horn where the dilution water enters, and 1 percent/day for the whole lake. As a result, lake quality has improved at least 50 percent in terms of chlorophyll a and total phosphorus and by nearly 100 percent in transparency. Pumping diluted lake water from Parker Horn beginning in 1982 and diverting sewage effluent in 1984 markedly improved water quality in a section that received treated effluent and little or no dilution water. Total phosphorus has declined by 90 percent and chlorophyll a by 60 percent, although transparency increased only about 0.2 m because of that section's shallowness. Diluted nitrate concentration in the inflow has been considered the cause for control of algae, but a switch from largely flood to spray irrigation, as well as sewage diversion, has resulted in lower inflow phosphorus concentrations and a gradual change from N to P limitation. Despite favorable improvements in average conditions, however, blooms of blue-green algae still develop in late summer. The largest bloom in the 10 + year study occurred from late August through September 1985, when the lake was well diluted and received no sewage. This is attributed to increased mixing following lower than normal temperature and to a 50 percent increase in internal phosphorus loading. Buoyant bluegreen algae rising from the sediment surface are hypothesized to be the transport mechanism. Keywords: Moses Lake; Washington; water quality; nutrient enrichment; algae; chlorophyll a; nitrogen; phosphorus; sewage effluent View Full Text ArticleSubscribe Affiliation: a Department of Civil Engineering, University of Washington Seattle, Washington DOI: 10.1080/07438140409354102 Published in: Lake and Reservoir Management, Volume 20, Issue 1 March 2004 , pages 76 - 84 Publication Frequency: 4 issues per year First Published on: 01 March 2004 Formats available: PDF (English) | Moses Lake has received dilution water in 9 of 10 years since treatment began in 1977. The average input for those years was 143 79 106 m3/yr over 93 days, which represents flushing rates of about 13 percent/day for Parker Horn where the dilution water enters, and 1 percent/day for the whole lake. As a result, lake quality has improved at least 50 percent in terms of chlorophyll a and total phosphorus and by nearly 100 percent in transparency. Pumping diluted lake water from Parker Horn beginning in 1982 and diverting sewage effluent in 1984 markedly improved water quality in a section that received treated effluent and little or no dilution water. Total phosphorus has declined by 90 percent and chlorophyll a by 60 percent, although transparency increased only about 0.2 m because of that section's shallowness. Diluted nitrate concentration in the inflow has been considered the cause for control of algae, but a switch from largely flood to spray irrigation, as well as sewage diversion, has resulted in lower inflow phosphorus concentrations and a gradual change from N to P limitation. Despite favorable improvements in average conditions, however, blooms of blue-green algae still develop in late summer. The largest bloom in the 10 + year study occurred from late August through September 1985, when the lake was well diluted and received no sewage. This is attributed to increased mixing following lower than normal temperature and to a 50 percent increase in internal phosphorus loading. Buoyant bluegreen algae rising from the sediment surface are hypothesized to be the transport mechanism. |
| Book Review | James F. LaBounty | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 1 | 2004 | 85 | Book Review Author: James F. LaBountya View Full Text ArticleSubscribe Affiliation: a Aquatic Scientist, Castle Rock, CO DOI: 10.1080/07438140409354103 Published in: Lake and Reservoir Management, Volume 20, Issue 1 March 2004 , page 85 Publication Frequency: 4 issues per year First Published on: 01 March 2004 Formats available: PDF (English) | |
| Changes in the Plant and Fish Communities in Enhanced Littoral Areas of Lake Kissimmee, Florida, Following a Habitat Enhancement | Kimberly I. Tugend; Micheal S. Allen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 1 | 2004 | 54 - 64 | Changes in the Plant and Fish Communities in Enhanced Littoral Areas of Lake Kissimmee, Florida, Following a Habitat Enhancement Authors: Kimberly I. Tugenda; Micheal S. Allena Abstract A 1995-96 habitat enhancement project was conducted at Lake Kissimmee, Florida, which included a major drawdown and organic sediment removal from about half of the lake's shoreline. Previous studies have compared enhanced versus control sites following habitat enhancements, but no studies have assessed how plant and fish communities change through time in enhanced habitats. We sampled plant and fish communities in two enhanced littoral areas three times each summer from 1998 to 2000. Quality fish habitat (i.e., sandy bottom, moderate coverage of aquatic macrophytes, high dissolved oxygen concentrations) was present in enhanced sites throughout this study. Irrespective of water level, plant abundance (percent area covered, PAC) and biomass increased during the study period, but mean plant biomass and abundance were < 2 kg · m-2 and < 50%, respectively, in 2000. Mean dissolved oxygen concentrations in enhanced sites generally exceeded 3 mg · L-1 in all years. Diverse fish communities also reflected quality habitat in enhanced sites. No fish variables differed between sites, but fish diversity and richness were highest during 1999 when water levels were high. Mean water depth and PAC, when significant, were positively related to fish variables (e.g., biomass, diversity). The results of this study suggest that the benefits of the 1995-96 Lake Kissimmee habitat enhancement were prolonged compared to a previous effort, which may be due, in part, to herbicide treatments. Keywords: drawdown; aquatic; macrophytes; fish community dynamics View Full Text ArticleSubscribe Affiliation: a Department of Fisheries and Aquatic Sciences, The University of Florida, Gainesville, FL DOI: 10.1080/07438140409354100 Published in: Lake and Reservoir Management, Volume 20, Issue 1 March 2004 , pages 54 - 64 Publication Frequency: 4 issues per year First Published on: 01 March 2004 Formats available: PDF (English) | A 1995-96 habitat enhancement project was conducted at Lake Kissimmee, Florida, which included a major drawdown and organic sediment removal from about half of the lake's shoreline. Previous studies have compared enhanced versus control sites following habitat enhancements, but no studies have assessed how plant and fish communities change through time in enhanced habitats. We sampled plant and fish communities in two enhanced littoral areas three times each summer from 1998 to 2000. Quality fish habitat (i.e., sandy bottom, moderate coverage of aquatic macrophytes, high dissolved oxygen concentrations) was present in enhanced sites throughout this study. Irrespective of water level, plant abundance (percent area covered, PAC) and biomass increased during the study period, but mean plant biomass and abundance were < 2 kg · m-2 and < 50%, respectively, in 2000. Mean dissolved oxygen concentrations in enhanced sites generally exceeded 3 mg · L-1 in all years. Diverse fish communities also reflected quality habitat in enhanced sites. No fish variables differed between sites, but fish diversity and richness were highest during 1999 when water levels were high. Mean water depth and PAC, when significant, were positively related to fish variables (e.g., biomass, diversity). The results of this study suggest that the benefits of the 1995-96 Lake Kissimmee habitat enhancement were prolonged compared to a previous effort, which may be due, in part, to herbicide treatments. |
| Assessing Iron Dynamics in the Release from a Stratified Reservoir | Steven L. Ashby; Stephen P. Faulkner; Robert P. Gambrell; Brenda A. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 1 | 2004 | 65 - 75 | Assessing Iron Dynamics in the Release from a Stratified Reservoir Authors: Steven L. Ashbya; Stephen P. Faulknerb; Robert P. Gambrellc; Brenda A. Smithd Abstract Field and laboratory studies were conducted to describe the fate of total, dissolved, and ferrous (Fe2+) iron in the release from a stratified reservoir with an anoxic hypolimnion. Concentrations of total iron in the tailwater indicated a first order removal process during a low flow release (0.6 m3 sec-1), yet negligible loss was observed during a period of increased discharge (2.8 m3 sec-1). Dissolved and ferrous iron concentrations in the tailwater were highly variable during both release regimes and did not follow responses based on theoretical predictions. Ferrous iron concentrations in unfiltered samples were consistently greater than concentrations observed in samples filtered separately through 0.4, 0.2, and 0.1 μm filters. Total iron removal in laboratory studies followed first order kinetics, but was twice that rate (0.077 mg L-1 hr-1) observed during low flow discharge in the tailwater (0.036 mg L-1 hr-1). Dissolved and ferrous iron losses in laboratory studies were rapid (~75% in the first 15 minutes and 95% within 1 hour), followed theoretical predictions, and were much faster than observations in the tailwater (~30% within the first hour). The presence of particulate forms of ferrous iron in the field and differences in removal rates observed in field and laboratory studies indicate a need for improved field assessment techniques and consideration of complexation reactions when assessing the dynamics of iron in reservoir releases and downstream impacts as a result of operation regimes. Keywords: iron; ferrous; ferric; tailwaters; reservoirs; water quality View Full Text ArticleSubscribe Affiliations: a Environmental Laboratory, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS b U.S. Geological Survey, Lafayette, LA c Louisiana State University, Wetland Biogeochemistry Institute, Baton Rouge, LA d Texas Commission on Environmental Quality, Austin, TX DOI: 10.1080/07438140409354101 Published in: Lake and Reservoir Management, Volume 20, Issue 1 March 2004 , pages 65 - 75 Publication Frequency: 4 issues per year First Published on: 01 March 2004 Formats available: PDF (English) | Field and laboratory studies were conducted to describe the fate of total, dissolved, and ferrous (Fe2+) iron in the release from a stratified reservoir with an anoxic hypolimnion. Concentrations of total iron in the tailwater indicated a first order removal process during a low flow release (0.6 m3 sec-1), yet negligible loss was observed during a period of increased discharge (2.8 m3 sec-1). Dissolved and ferrous iron concentrations in the tailwater were highly variable during both release regimes and did not follow responses based on theoretical predictions. Ferrous iron concentrations in unfiltered samples were consistently greater than concentrations observed in samples filtered separately through 0.4, 0.2, and 0.1 μm filters. Total iron removal in laboratory studies followed first order kinetics, but was twice that rate (0.077 mg L-1 hr-1) observed during low flow discharge in the tailwater (0.036 mg L-1 hr-1). Dissolved and ferrous iron losses in laboratory studies were rapid (~75% in the first 15 minutes and 95% within 1 hour), followed theoretical predictions, and were much faster than observations in the tailwater (~30% within the first hour). The presence of particulate forms of ferrous iron in the field and differences in removal rates observed in field and laboratory studies indicate a need for improved field assessment techniques and consideration of complexation reactions when assessing the dynamics of iron in reservoir releases and downstream impacts as a result of operation regimes. |
| Operation and Evaluation of Hypolimnetic Withdrawal in a Shallow Eutrophic Lake | Ronald H. Macdonald; Gregory A. Lawrence; Thomas P. Murphy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 20 | 1 | 2004 | 39 - 53 | Operation and Evaluation of Hypolimnetic Withdrawal in a Shallow Eutrophic Lake Authors: Ronald H. Macdonalda; Gregory A. Lawrencea; Thomas P. Murphyb Abstract Chain Lake is a small (46 ha), shallow (zmean = 6 m, zmax = 9 m) eutrophic lake in the interior of British Columbia, Canada. It suffers from severe blue-green algae blooms fed by internally loaded phosphorus. A hypolimnetic withdrawal system began operation in 1994, and is operated annually during the ice free period of the year. It is gravity driven (no mechanical pumps) and can operate at rates up to 80 L · s-1. A monitoring program implemented as part of the withdrawal installation evaluated total phosphorus export, lake water quality effects, and downstream environmental impacts. The withdrawal does not accelerate hydraulic flushing of the lake (residence time 0.5-3 years) but preferentially drains the water column below 5 m every 100 days and drains the deepest region of the lake (6-9 m) approximately every two weeks. Total phosphorus export in the first year of operation was 30 kg, and optimization of the operation strategy should increase export to 60 kg per year, resulting in a net export of total phosphorus from the lake. Long term monitoring of water quality has been performed by resident volunteers for nine years (1994 - 2002) using Secchi measurements. Only a few data are available prior to the withdrawal operation. A non-parametric trend test found statistically significant increases of the monthly median Secchi depth for June (p<0.05) and August (p<0.10). Optimization of the withdrawal operation to maximize phosphorus export can be done by earlier start-up after ice off and increasing flow rates during the most anoxic periods. Downstream concerns with respect to the withdrawal operation include: dissolved oxygen depletion observed at the withdrawal site and up to 500 m downstream; nutrient enrichment with elevated concentrations of phosphorus observed in the withdrawn water; and elevated levels of ammonia, iron, and manganese observed in the withdrawn water in the first year of monitoring. The effects of anoxic water discharge were partially mitigated by a fountain aerator at the discharge point which increased the dissolved oxygen in the withdrawal stream by up to 2.0 mg · L-1. Keywords: lake restoration; hypolimnetic withdrawal; internal loading; phosphorus; shallow lake View Full Text ArticleSubscribe Affiliations: a Department of Civil Engineering, University of British Columbia, Vancouver, B.C., Canada b National Water Research Institute Environment Canada, Burlington, Ontario, Canada DOI: 10.1080/07438140409354099 Published in: Lake and Reservoir Management, Volume 20, Issue 1 March 2004 , pages 39 - 53 Publication Frequency: 4 issues per year First Published on: 01 March 2004 Formats available: PDF (English) | Chain Lake is a small (46 ha), shallow (zmean = 6 m, zmax = 9 m) eutrophic lake in the interior of British Columbia, Canada. It suffers from severe blue-green algae blooms fed by internally loaded phosphorus. A hypolimnetic withdrawal system began operation in 1994, and is operated annually during the ice free period of the year. It is gravity driven (no mechanical pumps) and can operate at rates up to 80 L · s-1. A monitoring program implemented as part of the withdrawal installation evaluated total phosphorus export, lake water quality effects, and downstream environmental impacts. The withdrawal does not accelerate hydraulic flushing of the lake (residence time 0.5-3 years) but preferentially drains the water column below 5 m every 100 days and drains the deepest region of the lake (6-9 m) approximately every two weeks. Total phosphorus export in the first year of operation was 30 kg, and optimization of the operation strategy should increase export to 60 kg per year, resulting in a net export of total phosphorus from the lake. Long term monitoring of water quality has been performed by resident volunteers for nine years (1994 - 2002) using Secchi measurements. Only a few data are available prior to the withdrawal operation. A non-parametric trend test found statistically significant increases of the monthly median Secchi depth for June (p<0.05) and August (p<0.10). Optimization of the withdrawal operation to maximize phosphorus export can be done by earlier start-up after ice off and increasing flow rates during the most anoxic periods. Downstream concerns with respect to the withdrawal operation include: dissolved oxygen depletion observed at the withdrawal site and up to 500 m downstream; nutrient enrichment with elevated concentrations of phosphorus observed in the withdrawn water; and elevated levels of ammonia, iron, and manganese observed in the withdrawn water in the first year of monitoring. The effects of anoxic water discharge were partially mitigated by a fountain aerator at the discharge point which increased the dissolved oxygen in the withdrawal stream by up to 2.0 mg · L-1. |
| An Artificially Induced Planktothrix rubescens Surface Bloom in a Small Kettle Lake in Southern Ontario Compared to Blooms World-wide | Gertrud K. Nürnberg; Bruce D. LaZerte; Daniel D. Olding | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 4 | 2003 | 307 - 322 | An Artificially Induced Planktothrix rubescens Surface Bloom in a Small Kettle Lake in Southern Ontario Compared to Blooms World-wide Authors: Gertrud K. Nrnberga; Bruce D. LaZertea; Daniel D. Oldingb Abstract To combat hypolimnetic anoxia and sediment phosphorus release in a small, mesotrophic kettle lake on the Oakridge Moraine north of the Metropolitan Toronto, Southern Ontario, oxygenation and aeration was applied to the hypolimnion alternately during the summer of 1998 until mid-November and then to the entire water column until the end of December. This treatment coincided with the proliferation of a toxic strain of the purple cyanobacterium, Planktothrix rubescens, from almost undetectable values to bloom conditions under ice in the following winter and spring. Although small numbers of P. rubescens have been detected during several years before the treatment, prolonged artificial mixing in the fall and winter of 1998 distributed numerous filaments throughout the water column and to the surface when light was suitably low for these algae to survive and grow. Algae were supported by simultaneous entrainment and mixing of nutrients from the enriched bottom water. Such blooms of P. rubescens and related bluegreens have been found in many lakes with comparable characteristics and during similar episodes like those of the study lake. Lakes were typically stratified, mesotrophic hardwater lakes, with phosphorus levels that have recently been increasing to levels above 20 μg L-1. Blooms occurred during periods of low light and enhanced mixing, in several cases after treating the lake with whole-lake aeration and mixing. Recommendations to prevent such blooms in Lake Wilcox are (1) the discontinuation of artificial mixing during periods of natural destratification in the fall and winter, (2) the prevention of further eutrophication, and (3) the installation of an in-lake treatment, such as hypolimnetic withdrawal, to decrease internal phosphorus loading from anoxic sediment surfaces. Keywords: toxic Planktothrix rubescens blooms; Ontario kettle lake; eutrophication; artificial destratification; hypolimnetic aeration View Full Text ArticleSubscribe Affiliations: a Freshwater Research, Baysville, Ontario, Canada b Town of Richmond Hill, Richmond Hill, Ontario, Canada DOI: 10.1080/07438140309353941 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 December 2003 Formats available: PDF (English) | To combat hypolimnetic anoxia and sediment phosphorus release in a small, mesotrophic kettle lake on the Oakridge Moraine north of the Metropolitan Toronto, Southern Ontario, oxygenation and aeration was applied to the hypolimnion alternately during the summer of 1998 until mid-November and then to the entire water column until the end of December. This treatment coincided with the proliferation of a toxic strain of the purple cyanobacterium, Planktothrix rubescens, from almost undetectable values to bloom conditions under ice in the following winter and spring. Although small numbers of P. rubescens have been detected during several years before the treatment, prolonged artificial mixing in the fall and winter of 1998 distributed numerous filaments throughout the water column and to the surface when light was suitably low for these algae to survive and grow. Algae were supported by simultaneous entrainment and mixing of nutrients from the enriched bottom water. Such blooms of P. rubescens and related bluegreens have been found in many lakes with comparable characteristics and during similar episodes like those of the study lake. Lakes were typically stratified, mesotrophic hardwater lakes, with phosphorus levels that have recently been increasing to levels above 20 μg L-1. Blooms occurred during periods of low light and enhanced mixing, in several cases after treating the lake with whole-lake aeration and mixing. Recommendations to prevent such blooms in Lake Wilcox are (1) the discontinuation of artificial mixing during periods of natural destratification in the fall and winter, (2) the prevention of further eutrophication, and (3) the installation of an in-lake treatment, such as hypolimnetic withdrawal, to decrease internal phosphorus loading from anoxic sediment surfaces. |
| Impacts of a Soda Ash Facility on Onondaga Lake and the Seneca River, NY | Steven W. Effler; David A. Matthews | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 4 | 2003 | 285 - 306 | Impacts of a Soda Ash Facility on Onondaga Lake and the Seneca River, NY Authors: Steven W. Efflera; David A. Matthewsa Abstract A synthesis of the impacts of the operation (1884-1986) of a soda ash (Na2CO3) manufacturing facility on Onondaga Lake, NY, its tributaries, and adjoining portions of the river that receives the lake's outflow is presented, based on long-term programs of monitoring, process studies, and mathematical modeling. The lake was used as a source of cooling water and for the disposal of ionic (Cl- Na+, and Ca2+) waste, related solids and spent cooling water. At peak production the facility discharged ~1.3 106 metric tons of ionic waste to the lake annually. The soda ash facility had a profound impact on these ecosystems, by severely altering their structure and function. Portions of the two largest tributaries to the lake have been degraded from solids deposition associated with solution mining for NaCl (process reactant) and precipitation of Ca2+ waste (as CaCO3). The cooling water operation recycled phosphorus enriched hypolimnetic waters to the epilimnion. Ionic waste impacts on the lake and river included: (1) high salinity (S~3%o), (2) plunging inflows made dense by high S, that altered fundamental features of the lake's stratification regime and exacerbated the problem of severe dissolved oxygen (DO) depletion, (3) S-based density stratification and severe DO depletion over a 14 km reach of the river downstream of the lake, and (4) high levels of CaCO3 precipitation that reduced clarity, increased net sedimentation in pelagic areas, altered the character of near-shore sediments, and reduced alkalinity and pH. These impacts on the lake's chemistry and physical properties had profound effects on biological communities, including: (1) altered composition, (2) reduced richness and diversity, (3) limited macrophyte occurrence, (4) enhanced phytoplankton production, and (5) limited effectiveness of zooplankton grazing, thereby preventing intervals of high clarity. Closure of the facility resulted in dramatic improvements in water quality and ecological characteristics of these systems. Further improvement is expected as residual ionic waste loads decrease. Keywords: ionic pollution; chloride; sodium; calcium; industry; loads; tributary; stratification View Full Text ArticleSubscribe Affiliation: a Upstate Freshwater Institute, Syracuse, NY DOI: 10.1080/07438140309353940 Published in: Lake and Reservoir Management, Volume 19, Issue 4 December 2003 , pages 285 - 306 Publication Frequency: 4 issues per year First Published on: 01 December 2003 Formats available: PDF (English) | A synthesis of the impacts of the operation (1884-1986) of a soda ash (Na2CO3) manufacturing facility on Onondaga Lake, NY, its tributaries, and adjoining portions of the river that receives the lake's outflow is presented, based on long-term programs of monitoring, process studies, and mathematical modeling. The lake was used as a source of cooling water and for the disposal of ionic (Cl- Na+, and Ca2+) waste, related solids and spent cooling water. At peak production the facility discharged ~1.3 106 metric tons of ionic waste to the lake annually. The soda ash facility had a profound impact on these ecosystems, by severely altering their structure and function. Portions of the two largest tributaries to the lake have been degraded from solids deposition associated with solution mining for NaCl (process reactant) and precipitation of Ca2+ waste (as CaCO3). The cooling water operation recycled phosphorus enriched hypolimnetic waters to the epilimnion. Ionic waste impacts on the lake and river included: (1) high salinity (S~3%o), (2) plunging inflows made dense by high S, that altered fundamental features of the lake's stratification regime and exacerbated the problem of severe dissolved oxygen (DO) depletion, (3) S-based density stratification and severe DO depletion over a 14 km reach of the river downstream of the lake, and (4) high levels of CaCO3 precipitation that reduced clarity, increased net sedimentation in pelagic areas, altered the character of near-shore sediments, and reduced alkalinity and pH. These impacts on the lake's chemistry and physical properties had profound effects on biological communities, including: (1) altered composition, (2) reduced richness and diversity, (3) limited macrophyte occurrence, (4) enhanced phytoplankton production, and (5) limited effectiveness of zooplankton grazing, thereby preventing intervals of high clarity. Closure of the facility resulted in dramatic improvements in water quality and ecological characteristics of these systems. Further improvement is expected as residual ionic waste loads decrease. |
| Optimizing Artificial Aeration for Lake Winterkill Prevention | Theron G. Miller; W. C. Mackay | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 4 | 2003 | 355 - 363 | Optimizing Artificial Aeration for Lake Winterkill Prevention Authors: Theron G. Millera; W. C. Mackayb Abstract Optimizing winter lake aeration equipment has never been quantified in situ with regard to air or water flow, polynya size (the open water area created by the aerators), or energy required to maintain adequate dissolved oxygen (DO) concentrations. We conducted experiments using different combinations of compressors, air diffusers and mechanical surface aerators in winterkill lakes in northwest Alberta in order to determine a simplified approach to aeration equipment sizing. A hyperbolic relationship existed between energy use and polynya size. The largest polynya sizes were created using 0.15 kW ha-1 with both submersed air injection and surface aerators. However, adequate DO concentrations were maintained with surface aeration using one-third to one-half of the energy used for air injection. Optimal sizing occurred with 0.15-0.23 kW ha-1 for air injection and 0.06-0.1 kW ha-1 for surface aeration. Keywords: winter lake aeration; winterkill prevention; equipment sizing; energy use; mechanical surface aeration; air injection View Full Text ArticleSubscribe Affiliations: a Utah Department of Environmental, Salt Lake City, Utah b Department of Biological Sciences, University of Alberta, Edmonton, AB DOI: 10.1080/07438140309353945 Published in: Lake and Reservoir Management, Volume 19, Issue 4 December 2003 , pages 355 - 363 Publication Frequency: 4 issues per year First Published on: 01 December 2003 Formats available: PDF (English) | Optimizing winter lake aeration equipment has never been quantified in situ with regard to air or water flow, polynya size (the open water area created by the aerators), or energy required to maintain adequate dissolved oxygen (DO) concentrations. We conducted experiments using different combinations of compressors, air diffusers and mechanical surface aerators in winterkill lakes in northwest Alberta in order to determine a simplified approach to aeration equipment sizing. A hyperbolic relationship existed between energy use and polynya size. The largest polynya sizes were created using 0.15 kW ha-1 with both submersed air injection and surface aerators. However, adequate DO concentrations were maintained with surface aeration using one-third to one-half of the energy used for air injection. Optimal sizing occurred with 0.15-0.23 kW ha-1 for air injection and 0.06-0.1 kW ha-1 for surface aeration. |
| Reconstructing Eutrophication and Phosphorus Loading for Lake Volney, Minnesota: Combining Lake Sediments and Land-Use History to Establish ‘Natural’ Baselines for Management and Restoration | Charles E. Umbanhowar Jr.; Daniel R. Engstrom; Eric C. Bergman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 4 | 2003 | 364 - 372 | Reconstructing Eutrophication and Phosphorus Loading for Lake Volney, Minnesota: Combining Lake Sediments and Land-Use History to Establish 'Natural' Baselines for Management and Restoration Authors: Charles E. Umbanhowar Jr.a; Daniel R. Engstromb; Eric C. Bergmana Abstract Establishing management targets for lake nutrient inputs remains a major challenge to limnologists and resource managers concerned with the cultural eutrophication of lakes. In this study we used multiple sediment cores to reconstruct pre-Euroamerican (1650-1850) phosphorus (P) loading to Lake Volney, a hypereutrophic lake in Le Sueur County, Minnesota, and compared changes in P inputs to inferred changes in lake productivity based on biogenic silica (bSi). Euroamerican changes in land-use, as abstracted from census and tax records, were also compared with sedimentary proxies for soil erosion - loss-on-ignition and environmental magnetism. Whole-basin P accumulation in Lake Volney ranged from 0.31 - 0.39 g m-2 yr-1 prior to the arrival of Euroamerican agriculture in the 1850s. There-after P accumulation rose nearly three-fold largely due to increased fluxes of organic and non-apatite inorganic P. P inputs were highest (3.9 g m-2 yr-1) when organic, apatite and non-apatite P all peaked. Modern P accumulation rates of 1.3 g m-2 yr-1 match closely P-loading estimates based on monitoring data and mass-balance calculations. Lake productivity showed little change until the early 1900s when bSi accumulation rose 5-10x over pre-1900 values. The initial increase in P loading observed in the 1850s corresponds closely to the arrival of Euroamericans in the Lake Volney watershed. Causes for the second increase in P inputs (1910-1930) seem related to an overall increase in large animal numbers (swine and cattle) that began in the 1910s. The methods combined in this study provide site-specific reconstructions of trophic change and its causes that can be used to guide lake management and restoration. Keywords: eutrophication; Lake Volney; LOI; magnetics; paleolimnology; phosphorus; sediment; watershed View Full Text ArticleSubscribe Affiliations: a Department of Biology, St. Olaf College, Northfield, MN, USA b St. Croix Watershed Research Station Science Museum of Minnesota, Marine on St. Croix, MN, USA DOI: 10.1080/07438140309353946 Published in: Lake and Reservoir Management, Volume 19, Issue 4 December 2003 , pages 364 - 372 Publication Frequency: 4 issues per year First Published on: 01 December 2003 Formats available: PDF (English) | Establishing management targets for lake nutrient inputs remains a major challenge to limnologists and resource managers concerned with the cultural eutrophication of lakes. In this study we used multiple sediment cores to reconstruct pre-Euroamerican (1650-1850) phosphorus (P) loading to Lake Volney, a hypereutrophic lake in Le Sueur County, Minnesota, and compared changes in P inputs to inferred changes in lake productivity based on biogenic silica (bSi). Euroamerican changes in land-use, as ed from census and tax records, were also compared with sedimentary proxies for soil erosion - loss-on-ignition and environmental magnetism. Whole-basin P accumulation in Lake Volney ranged from 0.31 - 0.39 g m-2 yr-1 prior to the arrival of Euroamerican agriculture in the 1850s. There-after P accumulation rose nearly three-fold largely due to increased fluxes of organic and non-apatite inorganic P. P inputs were highest (3.9 g m-2 yr-1) when organic, apatite and non-apatite P all peaked. Modern P accumulation rates of 1.3 g m-2 yr-1 match closely P-loading estimates based on monitoring data and mass-balance calculations. Lake productivity showed little change until the early 1900s when bSi accumulation rose 5-10x over pre-1900 values. The initial increase in P loading observed in the 1850s corresponds closely to the arrival of Euroamericans in the Lake Volney watershed. Causes for the second increase in P inputs (1910-1930) seem related to an overall increase in large animal numbers (swine and cattle) that began in the 1910s. The methods combined in this study provide site-specific reconstructions of trophic change and its causes that can be used to guide lake management and restoration. |
| Evaluation of Beach Grooming Techniques on Escherichia coli Density in Foreshore Sand at North Beach, Racine, WI | Julie L. Kinzelman; Richard L. Whitman; Muruleedhara Byappanahalli; Emma Jackson; Robert C. Bagley | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 4 | 2003 | 349 - 354 | Evaluation of Beach Grooming Techniques on Escherichia coli Density in Foreshore Sand at North Beach, Racine, WI Authors: Julie L. Kinzelmana; Richard L. Whitmanb; Muruleedhara Byappanahallib; Emma Jacksonc; Robert C. Bagleya Abstract Elevated levels of Escherichia coli(E. coli) in bathing waters at North Beach, a popular recreational site in Racine, Wisconsin, have been a persistent problem often resulting in the issuance of poor water quality advisories. Moreover, waterfowl (mostly Larus delawarensis and L. argentatus) in nearshore and offshore areas are common and may serve as non-point sources for bacterial contamination of recreational waters. Current beach management practice involves daily mechanical grooming of the nearshore sand for aesthetics and removal of hazardous debris. However, this practice has not been evaluated in terms of its effects on E. coli loading to beach sand and potential introduction to contiguous swimming water. In this study, we tested E. coli responses to three treatments: mechanical groomer, daily and twice weekly hand raking, and a control (no raking/grooming). A randomized block design consisted of replicated treatments and one control (10 each), for a total of 40 blocks sampled daily for 10 days. Foreshore sand samples were collected by hand coring to an average depth of 10 cm. Median E. coli recovered were 73 (mechanically groomed), 27 (hand-raked daily), 32 (hand-raked twice weekly), and 22 (control) colony-forming units (CFU) per gram dry weight sand. E. coli counts in sand that was groomed were significantly higher than hand rakings and control (p <0.0001), and there was no significant difference between control and raking treatments (p<0.01). This study demonstrates the beach management implications related to grooming efficacy and the importance of understanding non-point sources of bacterial contamination. Keywords: beach grooming; foreshore sand; non-point pollution; water quality; E. coli View Full Text ArticleSubscribe Affiliations: a City of Racine Health Department Laboratory, Racine, WI b USGS Great Lakes Science Center, Porter, IN c University of Surrey, Guildford, Surrey, UK DOI: 10.1080/07438140309353944 Published in: Lake and Reservoir Management, Volume 19, Issue 4 December 2003 , pages 349 - 354 Publication Frequency: 4 issues per year First Published on: 01 December 2003 Formats available: PDF (English) | Elevated levels of Escherichia coli(E. coli) in bathing waters at North Beach, a popular recreational site in Racine, Wisconsin, have been a persistent problem often resulting in the issuance of poor water quality advisories. Moreover, waterfowl (mostly Larus delawarensis and L. argentatus) in nearshore and offshore areas are common and may serve as non-point sources for bacterial contamination of recreational waters. Current beach management practice involves daily mechanical grooming of the nearshore sand for aesthetics and removal of hazardous debris. However, this practice has not been evaluated in terms of its effects on E. coli loading to beach sand and potential introduction to contiguous swimming water. In this study, we tested E. coli responses to three treatments: mechanical groomer, daily and twice weekly hand raking, and a control (no raking/grooming). A randomized block design consisted of replicated treatments and one control (10 each), for a total of 40 blocks sampled daily for 10 days. Foreshore sand samples were collected by hand coring to an average depth of 10 cm. Median E. coli recovered were 73 (mechanically groomed), 27 (hand-raked daily), 32 (hand-raked twice weekly), and 22 (control) colony-forming units (CFU) per gram dry weight sand. E. coli counts in sand that was groomed were significantly higher than hand rakings and control (p <0.0001), and there was no significant difference between control and raking treatments (p<0.01). This study demonstrates the beach management implications related to grooming efficacy and the importance of understanding non-point sources of bacterial contamination. |
| Modeling Phosphorus Dynamics in a Shallow Lake During an Episodic Event | Xinjian Chen; Y. Peter Sheng | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 4 | 2003 | 323 - 340 | Modeling Phosphorus Dynamics in a Shallow Lake During an Episodic Event Authors: Xinjian Chenab; Y. Peter Shengc Abstract Wind, current, suspended sediment, dissolved oxygen (DO), pH and phosphorus data were collected in Lake Okeechobee, a shallow lake in south Florida, during a storm event in early 1993. Measured field data indicate that wind and wind-generated waves are major factors responsible for sediment resuspension in the lake. Data also show that soluble reactive phosphorus (SRP) and total dissolved phosphorus (TDP) were inversely-correlated with the DO concentration in the water column. This paper focuses on the use of a vertical one-dimensional model coupling phosphorus dynamics with hydrodynamics and sediment transport processes to simulate the observed episodic event. Model simulations confirmed that resuspension of sediments occurred during the episodic event, with the subsequent increases in phosphorus concentrations. Model results suggest that release of SRP from suspended sediment particles increases as the DO concentration in the water column decreases. By fitting simulated results with field data, an empirical formula describing the effect of the DO concentration on the release of inorganic phosphorus from resuspended sediments has been obtained. Further research to elucidate the detailed mechanism is recommended. Keywords: phosphorus dynamics; hydrodynamics; sediment transport processes; wind-induced waves; real-time simulation; shallow lake; Lake Okeechobee; release of inorganic phosphorus from sediments View Full Text ArticleSubscribe Affiliations: a Surface Water Improvement and Management Program, Southwest Florida Water Management District, Tampa, FL b Formerly Coastal & Oceanographic Engineering Program, University of Florida, Gainesville, FL c Coastal and Oceanographic Engineering Program, University of Florida, Gainesville, FL DOI: 10.1080/07438140309353942 Published in: Lake and Reservoir Management, Volume 19, Issue 4 December 2003 , pages 323 - 340 Publication Frequency: 4 issues per year First Published on: 01 December 2003 Formats available: PDF (English) | Wind, current, suspended sediment, dissolved oxygen (DO), pH and phosphorus data were collected in Lake Okeechobee, a shallow lake in south Florida, during a storm event in early 1993. Measured field data indicate that wind and wind-generated waves are major factors responsible for sediment resuspension in the lake. Data also show that soluble reactive phosphorus (SRP) and total dissolved phosphorus (TDP) were inversely-correlated with the DO concentration in the water column. This paper focuses on the use of a vertical one-dimensional model coupling phosphorus dynamics with hydrodynamics and sediment transport processes to simulate the observed episodic event. Model simulations confirmed that resuspension of sediments occurred during the episodic event, with the subsequent increases in phosphorus concentrations. Model results suggest that release of SRP from suspended sediment particles increases as the DO concentration in the water column decreases. By fitting simulated results with field data, an empirical formula describing the effect of the DO concentration on the release of inorganic phosphorus from resuspended sediments has been obtained. Further research to elucidate the detailed mechanism is recommended. |
| Cylindrospermopsis racihorskii in Three Central Florida Lakes: Population Dynamics, Controls, and Management Implications | Dean R. Dobberfuhl | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 4 | 2003 | 341 - 348 | Cylindrospermopsis racihorskii in Three Central Florida Lakes: Population Dynamics, Controls, and Management Implications Author: Dean R. Dobberfuhla Abstract Cylindrospermopsis racihorskii is a potentially toxic cyanobacterium that has begun appearing, or alternatively, increasing, and has come to dominate some Florida water bodies. C. racihorskii began exponentially increasing in Lake Jesup, Florida around 1997. As a result, the phytoplankton community in the lake has declined in terms of species richness and diversity. Compared to other lakes in the region this species is still maintaining relatively dynamic population cycles in the lake. Lake stage appears to affect C. racihorskii differently than the aggregate phytoplankton community in Lake Jesup. Correlation analysis suggests that magnesium limitation, among other factors, may be an important factor influencing C. racihorskii growth in Lake Jesup, but appears absent in Lake Apopka and Lake Griffin. Finally, increases in C. racihorskii are associated with increases in phytoplankton biomass yield per unit phosphorus, having important implications for lake management and restoration. Keywords: Cylindrospermopsis racihorskii; Florida; lake stage; magnesium limitation; P use efficiency View Full Text ArticleSubscribe Affiliation: a Division of Environmental Sciences, St. Johns River Water Management, District, Palatka, FL DOI: 10.1080/07438140309353943 Published in: Lake and Reservoir Management, Volume 19, Issue 4 December 2003 , pages 341 - 348 Publication Frequency: 4 issues per year First Published on: 01 December 2003 Formats available: PDF (English) | Cylindrospermopsis racihorskii is a potentially toxic cyanobacterium that has begun appearing, or alternatively, increasing, and has come to dominate some Florida water bodies. C. racihorskii began exponentially increasing in Lake Jesup, Florida around 1997. As a result, the phytoplankton community in the lake has declined in terms of species richness and diversity. Compared to other lakes in the region this species is still maintaining relatively dynamic population cycles in the lake. Lake stage appears to affect C. racihorskii differently than the aggregate phytoplankton community in Lake Jesup. Correlation analysis suggests that magnesium limitation, among other factors, may be an important factor influencing C. racihorskii growth in Lake Jesup, but appears absent in Lake Apopka and Lake Griffin. Finally, increases in C. racihorskii are associated with increases in phytoplankton biomass yield per unit phosphorus, having important implications for lake management and restoration. |
| Predicting the Frequencies of High Chlorophyll Levels in Florida Lakes from Average Chlorophyll or Nutrient Data | Roger W. Bachmann; Mark V. Hoyer; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 229 - 241 | Predicting the Frequencies of High Chlorophyll Levels in Florida Lakes from Average Chlorophyll or Nutrient Data Authors: Roger W. Bachmanna; Mark V. Hoyera; Daniel E. Canfield Jr.a Abstract An alternative to using average concentrations of phytoplankton chlorophyll in setting lake management goals is to use the frequency that chlorophyll concentrations exceed an established nuisance level. We analyzed 1473 lake-years of data on 438 Florida lakes to develop a series of tables that can be used to predict the frequencies that phytoplankton chlorophylls will exceed concentrations of 10, 20, 30, 40, 50, and 60 mg m-3 in Florida lakes based on the annual average concentrations of chlorophyll, total phosphorus, or total nitrogen. Different tables were created for lakes grouped by TN/TP ratios of >17, <17 but >10, and <10. These tables can be directly applied towards setting lake management goals for those Florida lakes that lack sufficient data to construct their own bloom frequency curves. Keywords: subtropical lakes; phosphorus; nitrogen; chlorophyll; water quality; bloom frequencies View Full Text ArticleSubscribe Affiliation: a Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL, USA DOI: 10.1080/07438140309354088 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | An alternative to using average concentrations of phytoplankton chlorophyll in setting lake management goals is to use the frequency that chlorophyll concentrations exceed an established nuisance level. We analyzed 1473 lake-years of data on 438 Florida lakes to develop a series of tables that can be used to predict the frequencies that phytoplankton chlorophylls will exceed concentrations of 10, 20, 30, 40, 50, and 60 mg m-3 in Florida lakes based on the annual average concentrations of chlorophyll, total phosphorus, or total nitrogen. Different tables were created for lakes grouped by TN/TP ratios of >17, <17 but >10, and <10. These tables can be directly applied towards setting lake management goals for those Florida lakes that lack sufficient data to construct their own bloom frequency curves. |
| Assessment of Social and Economic Factors For Management of Summer Pejerrey Recreational Fisheries in Pampean Lakes (Argentina) | Claudio R. M. Baigún; Ricardo L. Delfino | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 242 - 250 | Assessment of Social and Economic Factors For Management of Summer Pejerrey Recreational Fisheries in Pampean Lakes (Argentina) Authors: Claudio R. M. Baigna; Ricardo L. Delfinob Abstract This study illustrates the importance of assessing social and economic variables for management of recreational pejerrey fisheries in Pampean lakes. We conclude that summer pejerrey anglers differed by lakes in their motivations, preferences, and economic valuation of their fisheries and that most of the differences were attributed to travel distance, facilities, and quality of the fishery. We surveyed four fisheries located in different geographical areas, assessing preference and motivation by interviewing boat anglers at access points and then applying the contingent value method to assess economic values under current and different management conditions, (greater catch or larger size). Results indicated that anglers considered factors other than catching fish to be important, and a continuum of preferences and motivations was observed on a regional basis. Economic analysis yielding expenditures for study lakes averaged US$ 126,000. Consumer surplus for current conditions averaged 30% greater than actual trip costs. Under the preferred management option for the better fishing (greater catch or larger size, depending on the lake), average consumer surplus increased 65% over current expenditures, to US $208,000 per lake. The combination of socio-economic information representing non-market goods with traditional biological and fishery data will provide more comprehensive management criteria to achieve sustainable pejerrey fisheries in Pampean lakes. Keywords: pejerrey; Pampean lakes; contingent value method; consumer surplus; recreational fishery View Full Text ArticleSubscribe Affiliations: a Instituto Tecnolgico de Chascoms, (11B-INTECH), CONICET - Univer Sidad National de San Martin, de Buenos Aires, Argentina b Directin de Recursos Ictcolas y Acucolas, Buenos Aires, Argentina DOI: 10.1080/07438140309354089 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , pages 242 - 250 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | This study illustrates the importance of assessing social and economic variables for management of recreational pejerrey fisheries in Pampean lakes. We conclude that summer pejerrey anglers differed by lakes in their motivations, preferences, and economic valuation of their fisheries and that most of the differences were attributed to travel distance, facilities, and quality of the fishery. We surveyed four fisheries located in different geographical areas, assessing preference and motivation by interviewing boat anglers at access points and then applying the contingent value method to assess economic values under current and different management conditions, (greater catch or larger size). Results indicated that anglers considered factors other than catching fish to be important, and a continuum of preferences and motivations was observed on a regional basis. Economic analysis yielding expenditures for study lakes averaged US$ 126,000. Consumer surplus for current conditions averaged 30% greater than actual trip costs. Under the preferred management option for the better fishing (greater catch or larger size, depending on the lake), average consumer surplus increased 65% over current expenditures, to US $208,000 per lake. The combination of socio-economic information representing non-market goods with traditional biological and fishery data will provide more comprehensive management criteria to achieve sustainable pejerrey fisheries in Pampean lakes. |
| Phosphorus–Algal Bloom Relationships in Large Lakes of South Florida: Implications for Establishing Nutrient Criteria | Karl E. Havens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 222 - 228 | Phosphorus-Algal Bloom Relationships in Large Lakes of South Florida: Implications for Establishing Nutrient Criteria Author: Karl E. Havensa Abstract A simple cross-tabulation procedure was used to examine the relationship between total phosphorus (TP) concentration and algal bloom frequencies, based on chlorophyll a (Chl a), in seven large south Florida lakes. Monthly data from 1995-2000 were sorted by lake and TP concentration. For each lake, the sorted data were sub-divided into five intervals of equal sample size, and the frequency of occurrence of Chl a >20, 40, and 60 μg L-1 was determined and plotted against the median TP in each interval. “Critical†TP concentrations, at which there was a rapid increase in bloom frequency, were examined by visual inspection of these plots. There was considerable variation among lakes in regard to relationship of bloom frequency to TP. For Chl a >20 μg L-1, a rapid rise in frequency occurred at TP ranging from below 30 to greater than 40 μg L-1. For Chl a >40 μg L-1, a rapid rise in frequency began at TP concentrations ranging from 40 to above 70 μg L-1. The variation between lakes was not related to lake water total or dissolved N:P, but it was strongly related to color. Color explained 86% of the variation between lakes in terms of critical TP for increased frequency of Chl a >40 μg L-1, which is defined as an algal bloom by the State of Florida. Color, which reduces light penetration, may be particularly important in these lakes because they typically have homogeneous water columns that do not allow algae to migrate to and sustain high biomass near the surface, where there is adequate light for net growth. The influence of color is probably less in lakes with stable thermal stratification. The simple method used to evaluate the seven lakes could be generally applied, making use of routine water quality monitoring data, as long as one could specify an appropriate Chl a concentration and frequency for protecting the major use of particular water resources. Keywords: total phosphorus; chlorophyll a; bloom frequency analysis; numeric criteria View Full Text ArticleSubscribe Affiliation: a South Florida Water Management District, West Palm Beach, FL, USA DOI: 10.1080/07438140309354087 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , pages 222 - 228 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | A simple cross-tabulation procedure was used to examine the relationship between total phosphorus (TP) concentration and algal bloom frequencies, based on chlorophyll a (Chl a), in seven large south Florida lakes. Monthly data from 1995-2000 were sorted by lake and TP concentration. For each lake, the sorted data were sub-divided into five intervals of equal sample size, and the frequency of occurrence of Chl a >20, 40, and 60 μg L-1 was determined and plotted against the median TP in each interval. “Critical†TP concentrations, at which there was a rapid increase in bloom frequency, were examined by visual inspection of these plots. There was considerable variation among lakes in regard to relationship of bloom frequency to TP. For Chl a >20 μg L-1, a rapid rise in frequency occurred at TP ranging from below 30 to greater than 40 μg L-1. For Chl a >40 μg L-1, a rapid rise in frequency began at TP concentrations ranging from 40 to above 70 μg L-1. The variation between lakes was not related to lake water total or dissolved N:P, but it was strongly related to color. Color explained 86% of the variation between lakes in terms of critical TP for increased frequency of Chl a >40 μg L-1, which is defined as an algal bloom by the State of Florida. Color, which reduces light penetration, may be particularly important in these lakes because they typically have homogeneous water columns that do not allow algae to migrate to and sustain high biomass near the surface, where there is adequate light for net growth. The influence of color is probably less in lakes with stable thermal stratification. The simple method used to evaluate the seven lakes could be generally applied, making use of routine water quality monitoring data, as long as one could specify an appropriate Chl a concentration and frequency for protecting the major use of particular water resources. |
| Application of a Probabilistic Ammonia Model: Identification of Important Model Inputs and Critique of a TMDL Analysis for an Urban Lake | Rakesh K. Gelda; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 187 - 199 | Application of a Probabilistic Ammonia Model: Identification of Important Model Inputs and Critique of a TMDL Analysis for an Urban Lake Authors: Rakesh K. Geldaa; Steven W. Efflera Abstract Modeling analyses are conducted with a probabilistic mass balance ammonia model to demonstrate the important role that specifications of model inputs and toxicity standards by regulators can play in determining the assimilative capacity of polluted Onondaga Lake, NY, and to support a critical review of a related Total Maximum Daily Load (TMDL) analysis. More than 90% of the ammonia received by the lake is from a municipal wastewater treatment plant (Metro). It was found that various decisions to be made by regulators in management applications of the model greatly influence the lake's apparent assimilative capacity (TMDL). In particular, the following issues were critical: (1) anticipated hypolimnetic oxygenation treatment, (2) previously documented in-lake nitrification events, (3) effects of residual industrial pollution on pH, (4) effects of uncertainties and potential bias in pH measurements, (5) anticipated increases in population growth served by Metro, and (6) revisions in national guidance toxicity criteria prepared by the U. S. Environmental Protection Agency. Several limitations in the existing ammonia TMDL analysis are reported, including: (1) arbitrary specification of critical conditions, (2) omission of the important features of duration and allowable number of occurrences in the state standard, (3) identification of the wrong month as critical for determining the lake's assimilative capacity, (4) lack of recognition of the artificial assimilative capacity associated with the effects of residual industrial pollution, (5) the specified “margin of safety†was too low, given the level of modeling and input uncertainties, (6) anticipated increases in discharge from Metro were not considered, and (7) incorrect identification of the critical year for tributary hydrology. Recommendations are made to upgrade the ammonia TMDL analysis, including the supporting model framework and data sets. Keywords: TMDL; ammonia; modeling; toxicity; probabilistic; Monte Carlo; nitrogen; lakes View Full Text ArticleSubscribe Affiliation: a Upstate Freshwater Institute, Syracuse, NY DOI: 10.1080/07438140309354084 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , pages 187 - 199 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | Modeling analyses are conducted with a probabilistic mass balance ammonia model to demonstrate the important role that specifications of model inputs and toxicity standards by regulators can play in determining the assimilative capacity of polluted Onondaga Lake, NY, and to support a critical review of a related Total Maximum Daily Load (TMDL) analysis. More than 90% of the ammonia received by the lake is from a municipal wastewater treatment plant (Metro). It was found that various decisions to be made by regulators in management applications of the model greatly influence the lake's apparent assimilative capacity (TMDL). In particular, the following issues were critical: (1) anticipated hypolimnetic oxygenation treatment, (2) previously documented in-lake nitrification events, (3) effects of residual industrial pollution on pH, (4) effects of uncertainties and potential bias in pH measurements, (5) anticipated increases in population growth served by Metro, and (6) revisions in national guidance toxicity criteria prepared by the U. S. Environmental Protection Agency. Several limitations in the existing ammonia TMDL analysis are reported, including: (1) arbitrary specification of critical conditions, (2) omission of the important features of duration and allowable number of occurrences in the state standard, (3) identification of the wrong month as critical for determining the lake's assimilative capacity, (4) lack of recognition of the artificial assimilative capacity associated with the effects of residual industrial pollution, (5) the specified “margin of safety†was too low, given the level of modeling and input uncertainties, (6) anticipated increases in discharge from Metro were not considered, and (7) incorrect identification of the critical year for tributary hydrology. Recommendations are made to upgrade the ammonia TMDL analysis, including the supporting model framework and data sets. |
| The Potential Impact of Water Reallocation on Retention and Chlorophyll a in Weiss Lake, Alabama | Michael J. Maceina; David R. Bayne | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 200 - 207 | The Potential Impact of Water Reallocation on Retention and Chlorophyll a in Weiss Lake, Alabama Authors: Michael J. Maceinaa; David R. Baynea Abstract Water supply demand has increased in North Georgia and prompted government officials to propose a water reallocation plan that would permit two reservoirs upstream from Weiss Lake, Alabama to increase water withdrawals nearly three fold. Hydrologic modeling predicted lower flows in the Coosa River, the primary tributary of Weiss Lake, during average to below average flows (exceedences from 50 to 90%). Consequently, we predicted retention (reservoir volume/discharge) would increase in Weiss Lake under reallocation and using data from 1989 to 2000 as a baseline, we estimated the effect of longer retention on chlorophyll a concentrations (CHLA) and water clarity. CHLA measured during the growing season (April to October) was positively correlated (P < 0.01) to retention in both upstream and downstream reservoir regions and retention accounted for 24 to 28% of the variation in CHLA in linear and non-linear regression models. Under the reallocation scheme, increased retention (as predicted by HEC-5) could potentially cause an increase in CHLA of 8 to 15% compared to historic conditions if CHLA increased linearly with retention. If retention should increase 10 days with water reallocation, we estimated CHLA could increase about 20 to 30% under a “worst-case scenarioâ€. Water reallocation would have little or no impact on water clarity as Secchi transparency did not increase with lower CHLA concentrations. If longer retention does occur in Weiss Lake with water reallocation, a greater frequency of hypereutrophic conditions is expected. Keywords: chlorophyll a; retention; water reallocation; water clarity; algal blooms View Full Text ArticleSubscribe Affiliation: a Department of Fisheries, Auburn University, Alabama DOI: 10.1080/07438140309354085 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , pages 200 - 207 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | Water supply demand has increased in North Georgia and prompted government officials to propose a water reallocation plan that would permit two reservoirs upstream from Weiss Lake, Alabama to increase water withdrawals nearly three fold. Hydrologic modeling predicted lower flows in the Coosa River, the primary tributary of Weiss Lake, during average to below average flows (exceedences from 50 to 90%). Consequently, we predicted retention (reservoir volume/discharge) would increase in Weiss Lake under reallocation and using data from 1989 to 2000 as a baseline, we estimated the effect of longer retention on chlorophyll a concentrations (CHLA) and water clarity. CHLA measured during the growing season (April to October) was positively correlated (P < 0.01) to retention in both upstream and downstream reservoir regions and retention accounted for 24 to 28% of the variation in CHLA in linear and non-linear regression models. Under the reallocation scheme, increased retention (as predicted by HEC-5) could potentially cause an increase in CHLA of 8 to 15% compared to historic conditions if CHLA increased linearly with retention. If retention should increase 10 days with water reallocation, we estimated CHLA could increase about 20 to 30% under a “worst-case scenarioâ€. Water reallocation would have little or no impact on water clarity as Secchi transparency did not increase with lower CHLA concentrations. If longer retention does occur in Weiss Lake with water reallocation, a greater frequency of hypereutrophic conditions is expected. |
| Hypolimnetic Anoxia and Sediment Oxygen Demand in California Drinking Water Reservoirs | Marc W. Beutel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 208 - 221 | Hypolimnetic Anoxia and Sediment Oxygen Demand in California Drinking Water Reservoirs Author: Marc W. Beutela Abstract Summertime hypolimnetic anoxia can occur in productive drinking water reservoirs as a result of the decay of phytoplankton. Anoxic conditions promote ecological processes that degrade water quality through the release of problem-causing compounds from anoxic sediments including phosphates, ammonia, sulfides, methyl-mercury, iron and manganese. Hypolimnetic aeration systems are commonly installed in reservoirs to prevent hypolimnetic anoxia, but these systems have been historically undersized due to an underestimation of the magnitude of oxygen demand in the hypolimnion. To gain insight into the sizing of hypolimnetic aeration systems, this study evaluated the effects of water current and DO concentration near the sediment-water interface on sediment oxygen demand (SOD) in nine California drinking water reservoirs of various size (5-220 million m3) and trophic status (mean annual chlorophyll a of 0.5-11 μg L-1). SOD measured under quiescent conditions in 1.8 L experimental chambers ranged from 0.1-0.8 g m2 d1 Currents near the sediment-water interface of 3-8 cm s1 induced a two to four-fold increase in SOD, and resulted in a shift from first-order to zero-order DO uptake by sediment with respect to DO concentration in overlaying water. Results support the diffusive boundary layer model for SOD, with increased DO concentration and currents resulting in a larger SOD since there is a greater diffusional driving force across a smaller diffusive boundary layer. The study also evaluated the effects of trophic status and morphometry on hypolimnetic anoxia at the nine study sites. A number of significant correlations were discovered between factor quantifying hypolimnetic anoxia (areal and mass based hypolimnetic oxygen demand, SOD) and those quantifying morphometry (mean depth of the hypolimnion, volume of the hypolimnion) and trophic status (mean annual chlorophyll a). These results suggest that both increased size of the hypolimnion and higher productivity lead to higher oxygen demand within the hypolimnion. In addition, shallower reservoirs had a larger fraction of their total oxygen demand exerted in the sediments versus the water column. As a result, increased mixing at the sediment-water interface after start-up of aeration systems, and the resulting stimulation of SOD, will be particularly important in productive reservoirs of moderate depth (mean depth of 10-15 m). Aeration systems should be designed to enhance SOD by maintaining high oxygen concentrations and by inducing currents at the sediment-water interface. This will increase the depth of penetration of DO into sediment and promote beneficial aerobic biogeochemical reactions in surface sediments. Aeration systems that utilize pure-oxygen with horizontal discharge of highly oxygenated water across the sediment surface, rather than the traditional air-lift aeration system, will be more successful in satisfying SOD and improving hypolimnetic water quality. Keywords: hypolimnetic anoxia; hypolimnetic aeration; sediment oxygen demand; reservoir View Full Text ArticleSubscribe Affiliation: a Brown and Caldwell, Walnut Creek, California DOI: 10.1080/07438140309354086 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , pages 208 - 221 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | Summertime hypolimnetic anoxia can occur in productive drinking water reservoirs as a result of the decay of phytoplankton. Anoxic conditions promote ecological processes that degrade water quality through the release of problem-causing compounds from anoxic sediments including phosphates, ammonia, sulfides, methyl-mercury, iron and manganese. Hypolimnetic aeration systems are commonly installed in reservoirs to prevent hypolimnetic anoxia, but these systems have been historically undersized due to an underestimation of the magnitude of oxygen demand in the hypolimnion. To gain insight into the sizing of hypolimnetic aeration systems, this study evaluated the effects of water current and DO concentration near the sediment-water interface on sediment oxygen demand (SOD) in nine California drinking water reservoirs of various size (5-220 million m3) and trophic status (mean annual chlorophyll a of 0.5-11 μg L-1). SOD measured under quiescent conditions in 1.8 L experimental chambers ranged from 0.1-0.8 g m2 d1 Currents near the sediment-water interface of 3-8 cm s1 induced a two to four-fold increase in SOD, and resulted in a shift from first-order to zero-order DO uptake by sediment with respect to DO concentration in overlaying water. Results support the diffusive boundary layer model for SOD, with increased DO concentration and currents resulting in a larger SOD since there is a greater diffusional driving force across a smaller diffusive boundary layer. The study also evaluated the effects of trophic status and morphometry on hypolimnetic anoxia at the nine study sites. A number of significant correlations were discovered between factor quantifying hypolimnetic anoxia (areal and mass based hypolimnetic oxygen demand, SOD) and those quantifying morphometry (mean depth of the hypolimnion, volume of the hypolimnion) and trophic status (mean annual chlorophyll a). These results suggest that both increased size of the hypolimnion and higher productivity lead to higher oxygen demand within the hypolimnion. In addition, shallower reservoirs had a larger fraction of their total oxygen demand exerted in the sediments versus the water column. As a result, increased mixing at the sediment-water interface after start-up of aeration systems, and the resulting stimulation of SOD, will be particularly important in productive reservoirs of moderate depth (mean depth of 10-15 m). Aeration systems should be designed to enhance SOD by maintaining high oxygen concentrations and by inducing currents at the sediment-water interface. This will increase the depth of penetration of DO into sediment and promote beneficial aerobic biogeochemical reactions in surface sediments. Aeration systems that utilize pure-oxygen with horizontal discharge of highly oxygenated water across the sediment surface, rather than the traditional air-lift aeration system, will be more successful in satisfying SOD and improving hypolimnetic water quality. |
| News | G. Dennis | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 280 | News Author: G. Dennis View Full Text ArticleSubscribe DOI: 10.1080/07438140309354093 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , page 280 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | |
| Book Review | James J. Sartoris | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 281 | Book Review Author: James J. Sartorisa View Full Text ArticleSubscribe Affiliation: a Biological Resources Division, U.S. Geological Survey, Denvor, Colorado, USA DOI: 10.1080/07438140309354094 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , page 281 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | |
| 2003 OFFICERS & DIRECTORS | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 282 | 2003 OFFICERS & DIRECTORS View Full Text ArticleSubscribe DOI: 10.1080/07438140309354095 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , page 282 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | |
| An Alternative to Proposed Phosphorus TMDLs for the Management of Lake Okeechobee | Roger W. Bachmann; Mark V. Hoyer; Carlos Fernandez; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 251 - 264 | An Alternative to Proposed Phosphorus TMDLs for the Management of Lake Okeechobee Authors: Roger W. Bachmanna; Mark V. Hoyera; Carlos Fernandezb; Daniel E. Canfield Jr.a Abstract The U.S. Environmental Protection Agency and the Florida Department of Environmental Protection recently proposed total maximum daily loads (TMDL) of phosphorus for Lake Okeechobee of 198 t yr-1 and 140 t yr-1, respectively, with a goal of limiting algal blooms in the near-shore areas of the lake. We evaluated the reasonableness of these regulations by examining evidence of past changes in the lake, factors determining water quality, current phosphorus targets for the pelagic water, factors determining total phosphorus levels in the lake, expected benefits of the proposed TMDLs, and alternative management options. Available data are insufficient to demonstrate the degree of any recent eutrophication of the lake. Movement of the sediments in this shallow lake, perhaps by hurricane generated currents, casts doubt on reconstructions of lake history through sediment cores. We estimated presettlement phosphorus loading of 377 t yr-1, indicating that the lake has been eutrophic for a hundred or more years. The pelagic region of the lake is dominated by resuspended sediments that increase the phosphorus concentration and reduce light transmission. Thus, algal populations are limited by light and not phosphorus. As a result, there is no correlation between phosphorus and plankton chlorophylls and only a very weak correlation (r = 0.26) between Secchi depth and chlorophyll a. Living plankton account for only 15% of the total suspended solids in the pelagic region. Phosphorus targets for Lake Okeechobee have been based on conditions in the near-shore region along the western marshes. A concentration of 40 mg m3 of TP in the near-shore region would limit the frequency of algal blooms (chlorophyll a> mg m-3) to 15% of the year, the lowest bloom frequency observed in the closest pelagic stations in the past 28 years. Models indicate mat this frequency can be achieved with a pelagic TP concentration of between 72 and 92 mg m-3, though the TMDL models use 40 mg m-3 as their pelagic target TP concentration. Phosphorus levels in the pelagic region are not correlated with phosphorus inputs, so in spite of recent decreases in phosphorus loading to the lake, phosphorus concentrations continue to rise. This seems to be due to a reduction in phosphorus retention by the lake since 1973. The reason for the loss of phosphorus retention is not known, though there are indications that rising water levels and/or declining calcium concentrations might be involved. The data do not demonstrate that stringent phosphorus TMDLs will improve the lake. On the other hand, there is evidence that high water levels are responsible for reduced water quality in the lake and loss of macrophytes. A planned reduction in lake stage in 2000 made significant improvements in plant coverage, water clarity, and fish habitat without any change in the phosphorus regime. Water level controls seem to have more promise as a management tool for Lake Okeechobee than TMDLs for phosphorus. Keywords: restoration; eutrophication; aquatic macrophytes; phosphorus; lake management View Full Text ArticleSubscribe Affiliations: a Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL, USA b Hillsborough County Public Works Dept., Tampa, FL DOI: 10.1080/07438140309354090 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , pages 251 - 264 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | The U.S. Environmental Protection Agency and the Florida Department of Environmental Protection recently proposed total maximum daily loads (TMDL) of phosphorus for Lake Okeechobee of 198 t yr-1 and 140 t yr-1, respectively, with a goal of limiting algal blooms in the near-shore areas of the lake. We evaluated the reasonableness of these regulations by examining evidence of past changes in the lake, factors determining water quality, current phosphorus targets for the pelagic water, factors determining total phosphorus levels in the lake, expected benefits of the proposed TMDLs, and alternative management options. Available data are insufficient to demonstrate the degree of any recent eutrophication of the lake. Movement of the sediments in this shallow lake, perhaps by hurricane generated currents, casts doubt on reconstructions of lake history through sediment cores. We estimated presettlement phosphorus loading of 377 t yr-1, indicating that the lake has been eutrophic for a hundred or more years. The pelagic region of the lake is dominated by resuspended sediments that increase the phosphorus concentration and reduce light transmission. Thus, algal populations are limited by light and not phosphorus. As a result, there is no correlation between phosphorus and plankton chlorophylls and only a very weak correlation (r = 0.26) between Secchi depth and chlorophyll a. Living plankton account for only 15% of the total suspended solids in the pelagic region. Phosphorus targets for Lake Okeechobee have been based on conditions in the near-shore region along the western marshes. A concentration of 40 mg m3 of TP in the near-shore region would limit the frequency of algal blooms (chlorophyll a> mg m-3) to 15% of the year, the lowest bloom frequency observed in the closest pelagic stations in the past 28 years. Models indicate mat this frequency can be achieved with a pelagic TP concentration of between 72 and 92 mg m-3, though the TMDL models use 40 mg m-3 as their pelagic target TP concentration. Phosphorus levels in the pelagic region are not correlated with phosphorus inputs, so in spite of recent decreases in phosphorus loading to the lake, phosphorus concentrations continue to rise. This seems to be due to a reduction in phosphorus retention by the lake since 1973. The reason for the loss of phosphorus retention is not known, though there are indications that rising water levels and/or declining calcium concentrations might be involved. The data do not demonstrate that stringent phosphorus TMDLs will improve the lake. On the other hand, there is evidence that high water levels are responsible for reduced water quality in the lake and loss of macrophytes. A planned reduction in lake stage in 2000 made significant improvements in plant coverage, water clarity, and fish habitat without any change in the phosphorus regime. Water level controls seem to have more promise as a management tool for Lake Okeechobee than TMDLs for phosphorus. |
| Limited Effects of Barley Straw on Algae and Zooplankton in a Midwestern Pond | Joseph D. Boylan; Joseph E. Morris | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 265 - 271 | Limited Effects of Barley Straw on Algae and Zooplankton in a Midwestern Pond Authors: Joseph D. Boylana; Joseph E. Morrisa Abstract Researchers in the United Kingdom have reported that barley straw can be used to control a variety of planktonic algae, as well as the filamentous alga Cladophora spp. This method appears to be cost-effective, user-friendly, and environmentally sound. If these results could be obtained in the United States, using barley straw would be a good alternative to using copper sulfate. However, research has shown that barley straw must be subjected to well-oxygenated water for it to become anti-algal. Consequently, the sites of most studies conducted in the UK in which barley straw showed an effect have been somewhat lotic. Midwestern ponds are typically stagnant, and often become oxygen-poor during summer months, and therefore it is questionable whether barley straw would work. We attempted to control algae (filamentous and planktonic) growing in replicated limnocorrals that were built inside of a 1-ha pond; limnocorrals were stocked with three levels of barley straw. In addition, we tested whether the straw had effects on zooplankton community structure. No consistent degree of algal growth inhibition was observed for either alga type, and zooplankton community structure was not affected throughout this 14-week study (P < 0.10). Our results, as well as those of some other US researchers, may be partly explained by inadequate levels of oxygen within the decomposing straw caused by a lack of water exchange between the interstices of the straw and the water body. Keywords: barley straw; algae; zooplankton View Full Text ArticleSubscribe Affiliation: a Department of Animal Ecology, Iowa State University, Ames, IA DOI: 10.1080/07438140309354091 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , pages 265 - 271 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | Researchers in the United Kingdom have reported that barley straw can be used to control a variety of planktonic algae, as well as the filamentous alga Cladophora spp. This method appears to be cost-effective, user-friendly, and environmentally sound. If these results could be obtained in the United States, using barley straw would be a good alternative to using copper sulfate. However, research has shown that barley straw must be subjected to well-oxygenated water for it to become anti-algal. Consequently, the sites of most studies conducted in the UK in which barley straw showed an effect have been somewhat lotic. Midwestern ponds are typically stagnant, and often become oxygen-poor during summer months, and therefore it is questionable whether barley straw would work. We attempted to control algae (filamentous and planktonic) growing in replicated limnocorrals that were built inside of a 1-ha pond; limnocorrals were stocked with three levels of barley straw. In addition, we tested whether the straw had effects on zooplankton community structure. No consistent degree of algal growth inhibition was observed for either alga type, and zooplankton community structure was not affected throughout this 14-week study (P < 0.10). Our results, as well as those of some other US researchers, may be partly explained by inadequate levels of oxygen within the decomposing straw caused by a lack of water exchange between the interstices of the straw and the water body. |
| Is Littoral Habitat Affected by Residential Development and Land Use in Watersheds of Wisconsin Lakes? | Martin J. Jennings; Edward E. Emmons; Gene R. Hatzenbeler; Clayton Edwards; Michael A. Bozek | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 3 | 2003 | 272 - 279 | Is Littoral Habitat Affected by Residential Development and Land Use in Watersheds of Wisconsin Lakes? Authors: Martin J. Jenningsa; Edward E. Emmonsb; Gene R. Hatzenbelerc; Clayton Edwardsd; Michael A. Bozekc Abstract We measured differences in nearshore littoral zone habitat among lakes with different amounts of residential development and different patterns of watershed land use. Sampling stations were located at randomly selected sites within the nearshore littoral zone of limnologically similar lakes. An index of development density (based on counts of residential structures) and watershed cover types detected by satellite imagery summarized human influence in the riparian zone and watershed. To compare effects of development at local sites to effects of cumulative development density (structures/km shoreline), we used analysis of covariance. Quantity of woody debris, emergent vegetation and floating vegetation decreased at developed sites and in lakes with greater cumulative lakeshore development density. Littoral sediments contained more fine particles at developed sites and in lakes with greater development density. Sediment composition, quantity of vegetation, and woody debris were weakly associated with differences in watershed land use. Cumulative changes to watersheds and riparian zones are associated with measurable differences in littoral habitat that may not be detectable at smaller scales. For effective conservation, regulatory programs should consider the cumulative effects of development and land use on aquatic systems. Keywords: aquatic habitat; lakes; land use; development; spatial scale; macrophytes; substrate; woody debris View Full Text ArticleSubscribe Affiliations: a Wisconsin Department of Natural Resources, Bureau of Integrated Science Services, Spooner, WI b Wisconsin Department of Natural Resources, Bureau of Integrated Science Services, Monona, WI c Wisconsin Cooperative Fishery Research Unit, Biological Resources Division U.S.G.S., University of Wisconsin-Stevens Point, Stevens Point, WI d U.S.D.A. Forest Service, North Central Forest Experimental Station, Rhinelander, WI DOI: 10.1080/07438140309354092 Published in: Lake and Reservoir Management, Volume 19, Issue 3 September 2003 , pages 272 - 279 Publication Frequency: 4 issues per year First Published on: 01 September 2003 Formats available: PDF (English) | We measured differences in nearshore littoral zone habitat among lakes with different amounts of residential development and different patterns of watershed land use. Sampling stations were located at randomly selected sites within the nearshore littoral zone of limnologically similar lakes. An index of development density (based on counts of residential structures) and watershed cover types detected by satellite imagery summarized human influence in the riparian zone and watershed. To compare effects of development at local sites to effects of cumulative development density (structures/km shoreline), we used analysis of covariance. Quantity of woody debris, emergent vegetation and floating vegetation decreased at developed sites and in lakes with greater cumulative lakeshore development density. Littoral sediments contained more fine particles at developed sites and in lakes with greater development density. Sediment composition, quantity of vegetation, and woody debris were weakly associated with differences in watershed land use. Cumulative changes to watersheds and riparian zones are associated with measurable differences in littoral habitat that may not be detectable at smaller scales. For effective conservation, regulatory programs should consider the cumulative effects of development and land use on aquatic systems. |
| Limnology of Shallow Lakes in the Yukon Flats National Wildlife Refuge, Interior Alaska | Patricia J. Heglund; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | 133 - 140 | Limnology of Shallow Lakes in the Yukon Flats National Wildlife Refuge, Interior Alaska Authors: Patricia J. Heglunda; John R. Jonesa Abstract Data from 129 shallow riverine lakes within the Yukon Flats National Wildlife Refuge (between 65° 45'N and 67° 30'N and 142° 30'W and 150° 00'W) are presented as a baseline contribution to the regional limnology of Alaska. Ion composition reflected the composition of carbonate alluvium within the region; in most lakes Ca > Mg and bicarbonate dominated the anions (~90%). In lakes where alkali deposits occurred, Na, Mg and bicarbonate were the principal ions. Some 25% of the lakes were slightly brackish (conductivity >500 μS) to brackish. The lakes are colored, with 18 to 447 Pt-units. And, they are fertile, with over 70% classified as eu-or hypereutrophic on the basis of their nutrient content. Ratios of N:P suggested nitrogen was potentially limiting in about half the study lakes and was increasingly important at high P values. The yield of algal chlorophyll (Chl) per unit of plant nutrient was low in these lakes and Chl-nutrient relations explained less of the variance relative to published models. Invertebrate grazing potentially regulates Chi in some lakes. Typically these lakes freeze to the sediments and most do not support a permanent fishery. High ratios of organic suspended solids to Chl indicate detrital carbon contributes to the filterable carbon pool of these shallow lakes. Keywords: shallow lakes; water chemistry; colored lakes; nitrogen; phosphorus; algae View Full Text ArticleSubscribe Affiliation: a Department of Fisheries and Wildlife Sciences, University of Missouri, Columbia, MO DOI: 10.1080/07438140309354079 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: PDF (English) | Data from 129 shallow riverine lakes within the Yukon Flats National Wildlife Refuge (between 65° 45'N and 67° 30'N and 142° 30'W and 150° 00'W) are presented as a baseline contribution to the regional limnology of Alaska. Ion composition reflected the composition of carbonate alluvium within the region; in most lakes Ca > Mg and bicarbonate dominated the anions (~90%). In lakes where alkali deposits occurred, Na, Mg and bicarbonate were the principal ions. Some 25% of the lakes were slightly brackish (conductivity >500 μS) to brackish. The lakes are colored, with 18 to 447 Pt-units. And, they are fertile, with over 70% classified as eu-or hypereutrophic on the basis of their nutrient content. Ratios of N:P suggested nitrogen was potentially limiting in about half the study lakes and was increasingly important at high P values. The yield of algal chlorophyll (Chl) per unit of plant nutrient was low in these lakes and Chl-nutrient relations explained less of the variance relative to published models. Invertebrate grazing potentially regulates Chi in some lakes. Typically these lakes freeze to the sediments and most do not support a permanent fishery. High ratios of organic suspended solids to Chl indicate detrital carbon contributes to the filterable carbon pool of these shallow lakes. |
| General Limnology of Lakes Near Cook Inlet, Southcentral Alaska | John R. Jones; Michael A. Bell; John A. Baker; Jeffrey P. Koenings | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | 141 - 149 | General Limnology of Lakes Near Cook Inlet, Southcentral Alaska Authors: John R. Jonesa; Michael A. Bellb; John A. Bakerc; Jeffrey P. Koeningsde Abstract Data from lakes on the Kenai Peninsula (n = 111) and in the Matanuska-Susitna Valley (n = 108) show that lakes near the Cook Inlet, Alaska are moderately stained, with low turbidity and are predominately oligotrophic with a potential for phosphorus limitation. In both locations measures of salinity (as measured by conductivity) and pH were heterogenous and tied to hydrologic flowpaths. Overall, seepage lakes had lower pH, salinity, alkalinity, Ca, Mg and Si than drainage lakes. In our data set, both seepage and drainage lakes on the Kenai had lower alkalinity, Ca, and Si than corresponding lake types in Mat-Su. Most zooplankton biomass (ZB) measurements in the Cook Inlet lakes were <100 μg L-1 and over one-third were <10 μg L-1. Values of ZB were low relative to empirical models and did not increase with lake trophic state. Each of these lakes supports a fish community and the well-known effects of food web structure via grazing by planktivorous fish likely account for the observed ZB values. Environmental measurements and their patterns match earlier studies and collectively describe extant features of lake resources in this region of the southern boreal forest in southcentral Alaska. Keywords: Alaskan lakes; nitrogen; phosphorus; plankton; seepage lakes; drainage lakes View Full Text ArticleSubscribe Affiliations: a Department of Fisheries and Wildlife Sciences, University of Missouri, Columbia, MO b Department of Ecology and Evolution, State University of New York, Stony Brook, NY c Department of Biology, Clark University, Worcester, MA d Fisheries Rehabilitation, Enhancement and Development Division, Limnology Section, Alaska Department of Fish and Game, Soldotna, AK e Department of Fish and Wildlife, State of Washington, Olympia DOI: 10.1080/07438140309354080 Published in: Lake and Reservoir Management, Volume 19, Issue 2 June 2003 , pages 141 - 149 Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: PDF (English) | Data from lakes on the Kenai Peninsula (n = 111) and in the Matanuska-Susitna Valley (n = 108) show that lakes near the Cook Inlet, Alaska are moderately stained, with low turbidity and are predominately oligotrophic with a potential for phosphorus limitation. In both locations measures of salinity (as measured by conductivity) and pH were heterogenous and tied to hydrologic flowpaths. Overall, seepage lakes had lower pH, salinity, alkalinity, Ca, Mg and Si than drainage lakes. In our data set, both seepage and drainage lakes on the Kenai had lower alkalinity, Ca, and Si than corresponding lake types in Mat-Su. Most zooplankton biomass (ZB) measurements in the Cook Inlet lakes were <100 μg L-1 and over one-third were <10 μg L-1. Values of ZB were low relative to empirical models and did not increase with lake trophic state. Each of these lakes supports a fish community and the well-known effects of food web structure via grazing by planktivorous fish likely account for the observed ZB values. Environmental measurements and their patterns match earlier studies and collectively describe extant features of lake resources in this region of the southern boreal forest in southcentral Alaska. |
| Factors Affecting Iowa Lake and Reservoir Water Quality | Lorin K. Hatch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | 150 - 159 | Factors Affecting Iowa Lake and Reservoir Water Quality Author: Lorin K. Hatcha Abstract Iowa lake and reservoir water quality data collected during the summers of 1990 and 1992 were analyzed according to origin (lake vs. reservoir) and location, updating previous synoptic surveys. Morphometric comparisons between Iowa regions indicate unique characteristics for reservoirs, glacial lakes, oxbow lakes, and waterbodies on the Des Moines glacial lobe. All Iowa lakes and reservoirs are eutrophic although there is a significant range of water quality and within-region variability. Parameters such as chlorophyll a, total phosphorus (TP), and total nitrogen (TN) summer mean concentrations were highest on the Des Moines glacial lobe (means of 64 μg L-1, 164 μg L-1, and 4.4 mg L-1, respectively). A comparison of northern Iowa versus southern Minnesota lakes and southern Iowa versus northern Missouri reservoirs indicated that Iowa water quality is more eutrophic in both instances. Northern Iowa lakes had higher TN (3.0 mg L-1), total suspended solids (TSS, 39 mg L-1), and non-volatile suspended solids (NVSS, 18 mg L-1) summer mean concentrations than southern Minnesota lakes (2.1 mg L-1, 14 mg L-1, and 3 mg L-1, respectively). Southern Iowa reservoirs had higher TP (149 μg L-1), TN (1.8 mg L-1), TSS (34 mg L-1), and NVSS (25 mg L-1) summer mean concentrations than northern Missouri reservoirs (47 μg L-1, 0.7 mg L-1, 10 mg L-1, and 7 mg L-1, respectively). Keywords: ecoregions; Iowa; Minnesota; Missouri; morphometry; water quality View Full Text ArticleSubscribe Affiliation: a University of Minnesota Water Resources Center, St. Paul, MN DOI: 10.1080/07438140309354081 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: PDF (English) | Iowa lake and reservoir water quality data collected during the summers of 1990 and 1992 were analyzed according to origin (lake vs. reservoir) and location, updating previous synoptic surveys. Morphometric comparisons between Iowa regions indicate unique characteristics for reservoirs, glacial lakes, oxbow lakes, and waterbodies on the Des Moines glacial lobe. All Iowa lakes and reservoirs are eutrophic although there is a significant range of water quality and within-region variability. Parameters such as chlorophyll a, total phosphorus (TP), and total nitrogen (TN) summer mean concentrations were highest on the Des Moines glacial lobe (means of 64 μg L-1, 164 μg L-1, and 4.4 mg L-1, respectively). A comparison of northern Iowa versus southern Minnesota lakes and southern Iowa versus northern Missouri reservoirs indicated that Iowa water quality is more eutrophic in both instances. Northern Iowa lakes had higher TN (3.0 mg L-1), total suspended solids (TSS, 39 mg L-1), and non-volatile suspended solids (NVSS, 18 mg L-1) summer mean concentrations than southern Minnesota lakes (2.1 mg L-1, 14 mg L-1, and 3 mg L-1, respectively). Southern Iowa reservoirs had higher TP (149 μg L-1), TN (1.8 mg L-1), TSS (34 mg L-1), and NVSS (25 mg L-1) summer mean concentrations than northern Missouri reservoirs (47 μg L-1, 0.7 mg L-1, 10 mg L-1, and 7 mg L-1, respectively). |
| Comparative Limnology of Some Lakes in Interior Alaska | Jacqueline D. LaPerriere; Thomas D. Simpson; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | 122 - 132 | Comparative Limnology of Some Lakes in Interior Alaska Authors: Jacqueline D. LaPerrierea; Thomas D. Simpsona; John R. Jonesb Abstract Fifteen lakes in Interior Alaska (from about 62°N to 64°N and 142°W to 151°W) were sampled on three occasions during the open water season (mid-May to early September) in either 1993 or 1994. Lakes varied in elevation from 218 to 1124 m, in area from 33 to 6303 ha and in maximum depth from 4 to 49 m. Deep lakes thermally stratified during summer with lake cooling and destratification in some by August. Lakes with mean depth of <5 m were polymictic during summer. Anoxia was measured at depth in the most fertile lakes, and metalimnetic oxygen maxima in several lakes were associated with conditions favoring sub-surface algal peaks. There were near equal numbers of clear and stained lakes. One lake was eutrophic and the others were either oligo-or mesotrophic. About half the lakes had TN:TP < 11 by weight, indicating a regional potential for N-limitation. Among Interior lakes, salinity, as measured by conductivity and alkalinity was correlated with TN and TP which fits with the long-recognized pattern between parent geology and nutrients. These data are compared with previous lake studies in the Interior. Keywords: freshwater; nutrients; chlorophyll; water clarity; Alaska View Full Text ArticleSubscribe Affiliations: a Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, AK b Department of Fisheries and Wildlife Sciences, University of Missouri, Columbia, MO DOI: 10.1080/07438140309354078 Published in: Lake and Reservoir Management, Volume 19, Issue 2 June 2003 , pages 122 - 132 Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: PDF (English) | Fifteen lakes in Interior Alaska (from about 62°N to 64°N and 142°W to 151°W) were sampled on three occasions during the open water season (mid-May to early September) in either 1993 or 1994. Lakes varied in elevation from 218 to 1124 m, in area from 33 to 6303 ha and in maximum depth from 4 to 49 m. Deep lakes thermally stratified during summer with lake cooling and destratification in some by August. Lakes with mean depth of <5 m were polymictic during summer. Anoxia was measured at depth in the most fertile lakes, and metalimnetic oxygen maxima in several lakes were associated with conditions favoring sub-surface algal peaks. There were near equal numbers of clear and stained lakes. One lake was eutrophic and the others were either oligo-or mesotrophic. About half the lakes had TN:TP < 11 by weight, indicating a regional potential for N-limitation. Among Interior lakes, salinity, as measured by conductivity and alkalinity was correlated with TN and TP which fits with the long-recognized pattern between parent geology and nutrients. These data are compared with previous lake studies in the Interior. |
| Preface | Jack Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | iii | Preface Author: Jack Jonesa View Full Text ArticleSubscribe Affiliation: a University of Missouri, DOI: 10.1080/07438140309354075 Published in: Lake and Reservoir Management, Volume 19, Issue 2 June 2003 , page iii Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: PDF (English) | |
| Limnology of Harding Lake, Alaska: A Deep, Subarctic Lake | Jacqueline D. LaPerriere | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | 93 - 107 | Limnology of Harding Lake, Alaska: A Deep, Subarctic Lake Author: Jacqueline D. LaPerrierea Abstract Harding Lake (mean depth =16 m) located in Interior Alaska (64°25'N, 146°50'W), studied in the early 1970s in response to concerns about the impact of lakeshore development on water quality was sampled again in summer 1993 thereby providing comparative data over a 20-year period. The lake is usually dimictic but some years stratification begins under the ice and the lake misses a re-oxgenating overturn. One-third of the annual heat budget of about 19,600 cal cm2 is taken up by melting the ice cover. The lake is the common calcium-bicarbonate type but is dilute due to its relatively small watershed and dominance of siliceous material in the local lithography. Based on Secchi transparency, plant nutrients and algal chlorophyll the lake is oligotrophic, with no evidence the lake has been enriched during the study period. Annual primary productivity was estimated at 48 C m2 yr-1 and exhibited a seasonal pulse that began in early May and reached peak values just before ice-off at the end of May. Two chironomid species were identified that were indicative of oligotrophic conditions in this Nearctic lake. Data on vascular plant biomass and zooplankton are presented. Keywords: nearctic lake; nitrogen; phosphorus; phytoplankton; water clarity; thermal stratification View Full Text ArticleSubscribe Affiliation: a Alaska Cooperative Fish and Wildlife Research Unit, Biological Resources Division, U.S. Geological Survey, University of Alaska Fairbanks, Fairbanks, AK DOI: 10.1080/07438140309354076 Published in: Lake and Reservoir Management, Volume 19, Issue 2 June 2003 , pages 93 - 107 Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: | Harding Lake (mean depth =16 m) located in Interior Alaska (64°25'N, 146°50'W), studied in the early 1970s in response to concerns about the impact of lakeshore development on water quality was sampled again in summer 1993 thereby providing comparative data over a 20-year period. The lake is usually dimictic but some years stratification begins under the ice and the lake misses a re-oxgenating overturn. One-third of the annual heat budget of about 19,600 cal cm2 is taken up by melting the ice cover. The lake is the common calcium-bicarbonate type but is dilute due to its relatively small watershed and dominance of siliceous material in the local lithography. Based on Secchi transparency, plant nutrients and algal chlorophyll the lake is oligotrophic, with no evidence the lake has been enriched during the study period. Annual primary productivity was estimated at 48 C m2 yr-1 and exhibited a seasonal pulse that began in early May and reached peak values just before ice-off at the end of May. Two chironomid species were identified that were indicative of oligotrophic conditions in this Nearctic lake. Data on vascular plant biomass and zooplankton are presented. |
| Limnology of Lakes in Gates of the Arctic National Park and Preserve, Alaska | Jacqueline D. LaPerriere; John R. Jones; David K. Swanson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | 108 - 121 | Limnology of Lakes in Gates of the Arctic National Park and Preserve, Alaska Authors: Jacqueline D. LaPerrierea; John R. Jonesb; David K. Swansonc Abstract Limnological reconnaissance data were collected during summers 1992-93 and 1995 from 16 major lakes within Gates of the Arctic National Park and Preserve, Alaska (GAAR) located above the Arctic Circle. In GAAR the southern lakes (~67°N) and those in the Brooks Range foothills are in watersheds with taiga and tundra vegetation. The northern lakes (~68°N) are at higher elevations in the Brooks Range in watersheds that lie wholly beyond the treeline. Average sum of the cations for all lakes matches the world average for fresh waters and the average for drainage from tundra and taiga landscapes. Local lithography explains the measured decrease in calcium equivalents and silica, and an increase in magnesium with altitude because of more calcareous rock in the southern basins at low altitude and shale/conglomerate in northern mountain catchments. In most low altitude lakes Secchi depth was located in sub-surface algal peaks at temperatures averaging ~8.5 C cooler than the surface, typically with double the surface chlorophyll value. Mineral turbidity, and less so color, controlled transparency in several high altitude lakes where turbid inflows were a factor. Lakes were oligotrophic based on nutrients and algal chlorophylli, but a doubling of TP and concurrent halving of TN was measured in GAAR lakes with altitude. Both patterns were correlated with the decreasing density of terrestrial vegetation with altitude, resulting in a sharp decline in the TN:TP ratio. This pattern suggests sources of these nutrients change across the landscape continuum within GAAR described by altitude and vegetation zones. Nitrogen fixation associated with terrestrial vegetation most likely accounts for greater TN in lakes within the taiga and moist or wet tundra, whereas TN levels approximated the N content of regional rainfall in high elevation lakes with predominately barren land and prostrate shrub in the catchments. Ratios of TN:TP and Nutrient Stimulation Bioassays suggest P limitation was likely among low altitude lakes and N limitation increased in importance in lakes at high altitude. The particulate composition ratio (as C:N:P molar ratio) of these lakes averaged ~200:20:1. Keywords: arctic lake; mountain lake; nitrogen; phosphorus; phytoplankton; water clarity View Full Text ArticleSubscribe Affiliations: a Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, AK b Department of Fisheries and Wildlife Sciences, University of Missouri, Columbia, MO c Department of Plant, Animal and Soil Sciences, University of Alaska Fairbanks, Fairbanks, AK DOI: 10.1080/07438140309354077 Published in: Lake and Reservoir Management, Volume 19, Issue 2 June 2003 , pages 108 - 121 Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: | Limnological reconnaissance data were collected during summers 1992-93 and 1995 from 16 major lakes within Gates of the Arctic National Park and Preserve, Alaska (GAAR) located above the Arctic Circle. In GAAR the southern lakes (~67°N) and those in the Brooks Range foothills are in watersheds with taiga and tundra vegetation. The northern lakes (~68°N) are at higher elevations in the Brooks Range in watersheds that lie wholly beyond the treeline. Average sum of the cations for all lakes matches the world average for fresh waters and the average for drainage from tundra and taiga landscapes. Local lithography explains the measured decrease in calcium equivalents and silica, and an increase in magnesium with altitude because of more calcareous rock in the southern basins at low altitude and shale/conglomerate in northern mountain catchments. In most low altitude lakes Secchi depth was located in sub-surface algal peaks at temperatures averaging ~8.5 C cooler than the surface, typically with double the surface chlorophyll value. Mineral turbidity, and less so color, controlled transparency in several high altitude lakes where turbid inflows were a factor. Lakes were oligotrophic based on nutrients and algal chlorophylli, but a doubling of TP and concurrent halving of TN was measured in GAAR lakes with altitude. Both patterns were correlated with the decreasing density of terrestrial vegetation with altitude, resulting in a sharp decline in the TN:TP ratio. This pattern suggests sources of these nutrients change across the landscape continuum within GAAR described by altitude and vegetation zones. Nitrogen fixation associated with terrestrial vegetation most likely accounts for greater TN in lakes within the taiga and moist or wet tundra, whereas TN levels approximated the N content of regional rainfall in high elevation lakes with predominately barren land and prostrate shrub in the catchments. Ratios of TN:TP and Nutrient Stimulation Bioassays suggest P limitation was likely among low altitude lakes and N limitation increased in importance in lakes at high altitude. The particulate composition ratio (as C:N:P molar ratio) of these lakes averaged ~200:20:1. |
| Connectivity Influences Temporal Variation of Limnological Conditions in Missouri River Scour Lakes | Matthew F. Knowlton; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | 160 - 170 | Connectivity Influences Temporal Variation of Limnological Conditions in Missouri River Scour Lakes Authors: Matthew F. Knowltona; John R. Jonesa Abstract Two scour lakes in the Missouri River floodplain were sampled 20 months (April 1996 - December 1997) to examine effects of river inflow on mixing, seston, and nutrient dynamics. Lake NC-11 (≈4 ha) is deep (≈16 m), sheltered, dimictic, and connected to the river only during floods. Lake S-19 (≈20 ha) comprises two sub-basins, a deep (≈12 m) riverine forewater perennially connected to the river and a shallow (≈4 m), polymictic backwater of variable connectivity. Stratification in NC-11 affected, and was affected by, river inputs - cool inflows mixed completely and sometimes destratified the lake, warmer inflows were partly or completely confined to the epilimnion. Mixing between basins at S-19 was incomplete except during floods. During floods, concentrations of seston and particulate N and P were similar in the two basins of S-19, but conditions in the two basins diverged substantially during inter-flood periods as lower water levels reduced lateral exchange. Seston concentrations in NC-11 during floods were much less (≈90% less) than in S-19 or the river. In NC-11, algal blooms (chlorophyll 50-90 μg L-1) occurred in summer post-flood periods, but larger blooms (chlorophyll 50-256 μg L-1) occurred in the S-19 backwater during periods of low connectivity in all seasons. Nitrate-N peaked at >2 mg L-1 during floods but was exhausted during algal blooms along with up to ≈90% of dissolved phosphorus. Silica declined sharply (up to 93%) in many, but not all blooms, but remained >0.5 mg L-1 in all observations. Connectivity influenced many lake features and enhanced nutrient availability, but other floodplain lakes lacking river connections have similar algal biomass. Keywords: Missouri River; floodplain lakes; scour basins; nutrients; chlorophyll; suspended solids; connectivity; 1993 flood View Full Text ArticleSubscribe Affiliation: a Department of Fisheries and Wildlife Sciences, University of Missouri, Columbia, MO DOI: 10.1080/07438140309354082 Published in: Lake and Reservoir Management, Volume 19, Issue 2 June 2003 , pages 160 - 170 Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: | Two scour lakes in the Missouri River floodplain were sampled 20 months (April 1996 - December 1997) to examine effects of river inflow on mixing, seston, and nutrient dynamics. Lake NC-11 (≈4 ha) is deep (≈16 m), sheltered, dimictic, and connected to the river only during floods. Lake S-19 (≈20 ha) comprises two sub-basins, a deep (≈12 m) riverine forewater perennially connected to the river and a shallow (≈4 m), polymictic backwater of variable connectivity. Stratification in NC-11 affected, and was affected by, river inputs - cool inflows mixed completely and sometimes destratified the lake, warmer inflows were partly or completely confined to the epilimnion. Mixing between basins at S-19 was incomplete except during floods. During floods, concentrations of seston and particulate N and P were similar in the two basins of S-19, but conditions in the two basins diverged substantially during inter-flood periods as lower water levels reduced lateral exchange. Seston concentrations in NC-11 during floods were much less (≈90% less) than in S-19 or the river. In NC-11, algal blooms (chlorophyll 50-90 μg L-1) occurred in summer post-flood periods, but larger blooms (chlorophyll 50-256 μg L-1) occurred in the S-19 backwater during periods of low connectivity in all seasons. Nitrate-N peaked at >2 mg L-1 during floods but was exhausted during algal blooms along with up to ≈90% of dissolved phosphorus. Silica declined sharply (up to 93%) in many, but not all blooms, but remained >0.5 mg L-1 in all observations. Connectivity influenced many lake features and enhanced nutrient availability, but other floodplain lakes lacking river connections have similar algal biomass. |
| Fecal Bacteria, Nutrients, Chlorophyll, and Dissolved Oxygen in a Constructed Habitat Wetland Receiving Treated Municipal Effluent and River Water | Matthew F. Knowlton; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 2 | 2003 | 171 - 183 | Fecal Bacteria, Nutrients, Chlorophyll, and Dissolved Oxygen in a Constructed Habitat Wetland Receiving Treated Municipal Effluent and River Water Authors: Matthew F. Knowltona; John R. Jonesa Abstract The Eagle Bluffs Conservation Area (Eagle Bluffs) in central Missouri includes about 400 ha of floodable pools and channels managed as seasonal or permanent habitat wetlands using treated municipal effluent from the Columbia Wastewater Treatment Wetland. Effluent, which is used year around, provides about half the annual water input and is supplemented during waterfowl migrations by pumping from the adjacent Missouri River. Infiltration rates are high (≈900 cm yr-1) because of high soil permeability. Water quality of inflows and selected pools and channels on Eagle Bluffs has been monitored since wetland flooding began in 1994 because of concerns about possible negative effects of wastewater and interest in the dynamics of nutrients and algal biomass in the system. Compared to river water, effluent typically had high concentrations of fecal bacteria, chloride, dissolved phosphorus, and dissolved nitrogen, especially ammonia-N. In the water Distribution Channel (DC) and terminal wetland pools of Eagle Bluffs fecal bacteria decline rapidly and are usually within the range suitable for human water contact (<200 cells 100 mL-1). Phosphorus and nitrogen concentrations vary with the relative inputs of effluent and river water and in situ losses. On the basis of comparison with chloride concentrations, over half of incoming phosphorus and nitrogen are lost from surface water to sediments, plant uptake or denitrification. Nutrient losses from the large proportion of water lost to infiltration are not known. Chlorophyll concentrations in the DC and wetland pools exceeded 100 μg L-1 in 35% of observations, but chlorophyll and organic matter concentrations on Eagle Bluffs are similar to those in Missouri River oxbow lakes with much lower nutrient inputs. Ammonia concentration frequently exceed USEPA acute and chronic toxicity criteria, but fish seem to thrive on Eagle Bluffs. Overall, negative effects of effluent use seem minimal with respect to intended uses of the habitat wetland, but effects of infiltrating effluent on subsurface drinking water supplies are still in question. Keywords: habitat wetland; wastewater; Missouri River; nutrients; fecal bacteria; chloride; chlorophyll; dissolved oxygen View Full Text ArticleSubscribe Affiliation: a Department of Fisheries and Wildlife Sciences, University of Missouri, Columbia, MO, USA DOI: 10.1080/07438140309354083 Published in: Lake and Reservoir Management, Volume 19, Issue 2 June 2003 , pages 171 - 183 Publication Frequency: 4 issues per year First Published on: 01 June 2003 Formats available: | The Eagle Bluffs Conservation Area (Eagle Bluffs) in central Missouri includes about 400 ha of floodable pools and channels managed as seasonal or permanent habitat wetlands using treated municipal effluent from the Columbia Wastewater Treatment Wetland. Effluent, which is used year around, provides about half the annual water input and is supplemented during waterfowl migrations by pumping from the adjacent Missouri River. Infiltration rates are high (≈900 cm yr-1) because of high soil permeability. Water quality of inflows and selected pools and channels on Eagle Bluffs has been monitored since wetland flooding began in 1994 because of concerns about possible negative effects of wastewater and interest in the dynamics of nutrients and algal biomass in the system. Compared to river water, effluent typically had high concentrations of fecal bacteria, chloride, dissolved phosphorus, and dissolved nitrogen, especially ammonia-N. In the water Distribution Channel (DC) and terminal wetland pools of Eagle Bluffs fecal bacteria decline rapidly and are usually within the range suitable for human water contact (<200 cells 100 mL-1). Phosphorus and nitrogen concentrations vary with the relative inputs of effluent and river water and in situ losses. On the basis of comparison with chloride concentrations, over half of incoming phosphorus and nitrogen are lost from surface water to sediments, plant uptake or denitrification. Nutrient losses from the large proportion of water lost to infiltration are not known. Chlorophyll concentrations in the DC and wetland pools exceeded 100 μg L-1 in 35% of observations, but chlorophyll and organic matter concentrations on Eagle Bluffs are similar to those in Missouri River oxbow lakes with much lower nutrient inputs. Ammonia concentration frequently exceed USEPA acute and chronic toxicity criteria, but fish seem to thrive on Eagle Bluffs. Overall, negative effects of effluent use seem minimal with respect to intended uses of the habitat wetland, but effects of infiltrating effluent on subsurface drinking water supplies are still in question. |
| The Use of a Pattern Judgement Model to Assess Fish Habitat Suitability in Two Colorado Reservoirs | Eric P. Bergersen; Patrick J. Martinez | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | 55 - 78 | The Use of a Pattern Judgement Model to Assess Fish Habitat Suitability in Two Colorado Reservoirs Authors: Eric P. Bergersena; Patrick J. Martinezb Abstract The suitability of two Colorado reservoirs to support an array of common fish species was assessed using a pattern judgement model. The model employs an expert panel to predict habitat suitability based on easily measured structural characteristics of the reservoir basin, local site climate, operational regime, and inflow characteristics. Model predictions, made before Kenney Reservoir was filled, indicated mat common carp (Cyprinus carpio) and black crappie (Pomoxis nigromaculatus) would dominate the fish community in this reservoir. Sampling in the decade following completion of the dam substantiated this prediction. When additional species were added to the model and their likely performance in Kenney Reservoir evaluated, predictions offish community composition closely followed trends observed in reservoir species composition. A proposed enlargement of an existing reservoir was evaluated with the model to predict what species might prosper as a result of the new configuration of the reservoir basin and inundation of new land areas. None of the 10 species evaluated were predicted to flourish in the new habitat provided by the enlargement. Predictions were consistent with the low abundance of these species in the existing reservoir and the probable lack of suitable habitat in the enlargement area. The pattern judgement model can be used to explore management options dealing with probable species performance as a function of the quality of available habitat using relatively static data garnered at low cost. The model's flexibility allows modification of input variable values to reflect local conditions or specific needs without altering model logic. Guidance is provided for adding more species to the model to broaden its applicability to other waters. Keywords: reservoir fish habitat; pattern judgement model View Full Text ArticleSubscribe Affiliations: a Colorado Cooperative Fish and Wildlife Research Unit, Colorado State University, Fort Collins, Colorado b Colorado Division of Wildlife, Grand Junction, Colorado DOI: 10.1080/07438140309353989 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: PDF (English) | The suitability of two Colorado reservoirs to support an array of common fish species was assessed using a pattern judgement model. The model employs an expert panel to predict habitat suitability based on easily measured structural characteristics of the reservoir basin, local site climate, operational regime, and inflow characteristics. Model predictions, made before Kenney Reservoir was filled, indicated mat common carp (Cyprinus carpio) and black crappie (Pomoxis nigromaculatus) would dominate the fish community in this reservoir. Sampling in the decade following completion of the dam substantiated this prediction. When additional species were added to the model and their likely performance in Kenney Reservoir evaluated, predictions offish community composition closely followed trends observed in reservoir species composition. A proposed enlargement of an existing reservoir was evaluated with the model to predict what species might prosper as a result of the new configuration of the reservoir basin and inundation of new land areas. None of the 10 species evaluated were predicted to flourish in the new habitat provided by the enlargement. Predictions were consistent with the low abundance of these species in the existing reservoir and the probable lack of suitable habitat in the enlargement area. The pattern judgement model can be used to explore management options dealing with probable species performance as a function of the quality of available habitat using relatively static data garnered at low cost. The model's flexibility allows modification of input variable values to reflect local conditions or specific needs without altering model logic. Guidance is provided for adding more species to the model to broaden its applicability to other waters. |
| The Sounds of Silence: Trends in the Regulation of Personal Watercraft | Tamara A. Dudiak | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | 45 - 54 | The Sounds of Silence: Trends in the Regulation of Personal Watercraft Author: Tamara A. Dudiaka Abstract In recent years, U.S. courts have upheld arguably objectionable local ordinances that single out particular kinds of vessels such as the personal watercraft. Communities across the country have grown bolder in recent years as congestion on U.S. waters increases and state enabling legislation becomes more specific in terms of the watercraft to be regulated, the zoning tools to be employed, and the objectives to be achieved. Standard police power objectives, which form the basis for boating regulations, are now articulated not only in terms of protecting public health, safety and welfare, but in terms of protecting the environment, encouraging historical uses, and preserving peace and tranquility. The purpose of this paper is to provide an overview of boating regulatory authority and watercraft specific regulations as well as discuss and offer an analysis of recent key court decisions and trends in personal watercraft regulation. Courts have been reluctant to question the judgment of local government and will uphold a regulation provided certain basic elements are present. That these local regulations have been upheld is indicative of a greater judicial responsiveness to ordinances whose primary objective is not simply public welfare and safety, but more specifically the protection of natural resources and environmental integrity. Keywords: personal watercraft; boating regulations; boating ordinances; surface use management View Full Text ArticleSubscribe Affiliation: a College of Natural Resources, Stevens Point, WI DOI: 10.1080/07438140309353988 Published in: Lake and Reservoir Management, Volume 19, Issue 1 March 2003 , pages 45 - 54 Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: | In recent years, U.S. courts have upheld arguably objectionable local ordinances that single out particular kinds of vessels such as the personal watercraft. Communities across the country have grown bolder in recent years as congestion on U.S. waters increases and state enabling legislation becomes more specific in terms of the watercraft to be regulated, the zoning tools to be employed, and the objectives to be achieved. Standard police power objectives, which form the basis for boating regulations, are now articulated not only in terms of protecting public health, safety and welfare, but in terms of protecting the environment, encouraging historical uses, and preserving peace and tranquility. The purpose of this paper is to provide an overview of boating regulatory authority and watercraft specific regulations as well as discuss and offer an analysis of recent key court decisions and trends in personal watercraft regulation. Courts have been reluctant to question the judgment of local government and will uphold a regulation provided certain basic elements are present. That these local regulations have been upheld is indicative of a greater judicial responsiveness to ordinances whose primary objective is not simply public welfare and safety, but more specifically the protection of natural resources and environmental integrity. |
| Preface | Tim Asplund | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | iii - iv | Preface Author: Tim Asplunda View Full Text ArticleSubscribe Affiliation: a Wisconsin Department of Natural Resources, Madison, WI, USA DOI: 10.1080/07438140309353983 Published in: Lake and Reservoir Management, Volume 19, Issue 1 March 2003 , pages iii - iv Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: | |
| Development and Application of a Phosphorus Balance Model for Lake Istokpoga, Florida | William W. Walker; Karl E. Havens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | 79 - 91 | Development and Application of a Phosphorus Balance Model for Lake Istokpoga, Florida Authors: William W. Walker; Karl E. Havensa Abstract Hydrologic and phosphorus (P) mass balance models were constructed for Lake Istokpoga, a large shallow lake in Florida, USA. The objective was to use the models to determine whether there have been long-term trends in the processing of P by this lake, potentially impacting P exports to a downstream ecosystem (Lake Okeechobee). Higher lake P concentrations and outflow loads in recent years appear to be explained by higher runoff. A detailed basin survey will be needed to determine whether changes in land use in the predominantly agricultural and urban watershed also may have contributed to the increased P loads. Lake total P concentrations did not display a significant historical trend, nor did the lake's capacity to assimilate P. A number of statistical approaches are demonstrated that could have general application in establishing nutrient mass balances for lakes with sparse data sets for tributary flows and/or concentrations. Daily simulations of lake phosphorus and chloride levels demonstrate me feasibility of dynamic mass-balance modeling in shallow Florida lakes using simple first-order phosphorus removal kinetics. The model developed here could be used in setting a total maximum daily load (TMDL) for P, once an in-lake concentration goal has been specified. Keywords: Phosphorus; mass balance modeling; Lake Istokpoga; Florida View Full Text ArticleSubscribe Affiliation: a South Florida Water Management District, West Palm Beach, Florida DOI: 10.1080/07438140309353990 Published in: Lake and Reservoir Management, Volume 19, Issue 1 March 2003 , pages 79 - 91 Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: | Hydrologic and phosphorus (P) mass balance models were constructed for Lake Istokpoga, a large shallow lake in Florida, USA. The objective was to use the models to determine whether there have been long-term trends in the processing of P by this lake, potentially impacting P exports to a downstream ecosystem (Lake Okeechobee). Higher lake P concentrations and outflow loads in recent years appear to be explained by higher runoff. A detailed basin survey will be needed to determine whether changes in land use in the predominantly agricultural and urban watershed also may have contributed to the increased P loads. Lake total P concentrations did not display a significant historical trend, nor did the lake's capacity to assimilate P. A number of statistical approaches are demonstrated that could have general application in establishing nutrient mass balances for lakes with sparse data sets for tributary flows and/or concentrations. Daily simulations of lake phosphorus and chloride levels demonstrate me feasibility of dynamic mass-balance modeling in shallow Florida lakes using simple first-order phosphorus removal kinetics. The model developed here could be used in setting a total maximum daily load (TMDL) for P, once an in-lake concentration goal has been specified. |
| Physical Impacts of Wind and Boat Traffic on Clear Lake, Iowa, USA | James L. Anthony; John A. Downing | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | 1-14 | Physical Impacts of Wind and Boat Traffic on Clear Lake, Iowa, USA Authors: James L. Anthonyab; John A. Downingc Abstract Clear Lake is a shallow (Zmean=2.9 m), eutrophic (TPmean=188 μgL-1) lake that is intensively used forrecreation. After a century of intense agriculture in the watershed, the bottom is covered with nutrient-rich organic sediments. We monitored wind, boat traffic and turbidity and found that resuspension of this sediment by wind-induced waves and recreational boat traffic contributes to daily, often substantial, nutrient fluxes. Intensive monitoring over a wind-event showed that total phosphorus concentrations can increase by 100% over a diel period and ammonia concentrations increase to levels near to those toxic to fish at the peak of winds. GIS of the digitally analyzed lake basin coupled with physical models show that when wind speeds exceed 10 ms-1 (22 mph), >46% of the lake's benthic surface area may become mobile. Wind speeds >20 ms-1 (44 mph) can mobilize >98% of the lake bottom sediment surface area. The correlation between boat traffic and sediment resuspension was weak (r2 = 0.23) in near-shore monitoring due to confounding by wind and other factors but heavy boat traffic appears to exacerbate wind-induced resuspension and may slow the resettlement of resuspended sedimente. Boat traffic correlated with up to 50% increases in turbidity. Resuspension of sediments by boats is likely to occur across 56% of the lake area. Benthic sediment resuspension may contribute to the suppression of fish and macrophyte communities, domination of the phytoplankton community by Cyanobacteria, suspension of toxic ammonia, and increased restoration time-scales. Keywords: boats; internal loading; nutrients; resuspension; sediment; turbulence; wind View Full Text ArticleSubscribe Affiliations: a Department of Animal Ecology, 124 Science II, Iowa State University, Ames, IA b Department of Environmentl, Population, and Oraganismic Biology, University of Colorado, Boulder, CO c Department of Ecology, Evolution, and Organismal Biology, 124 Science II, Iowa State University, Ames, IA DOI: 10.1080/07438140309353984 Published in: Lake and Reservoir Management, Volume 19, Issue 1 March 2003 , pages 1 - 14 Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: | Clear Lake is a shallow (Zmean=2.9 m), eutrophic (TPmean=188 μgL-1) lake that is intensively used forrecreation. After a century of intense agriculture in the watershed, the bottom is covered with nutrient-rich organic sediments. We monitored wind, boat traffic and turbidity and found that resuspension of this sediment by wind-induced waves and recreational boat traffic contributes to daily, often substantial, nutrient fluxes. Intensive monitoring over a wind-event showed that total phosphorus concentrations can increase by 100% over a diel period and ammonia concentrations increase to levels near to those toxic to fish at the peak of winds. GIS of the digitally analyzed lake basin coupled with physical models show that when wind speeds exceed 10 ms-1 (22 mph), >46% of the lake's benthic surface area may become mobile. Wind speeds >20 ms-1 (44 mph) can mobilize >98% of the lake bottom sediment surface area. The correlation between boat traffic and sediment resuspension was weak (r2 = 0.23) in near-shore monitoring due to confounding by wind and other factors but heavy boat traffic appears to exacerbate wind-induced resuspension and may slow the resettlement of resuspended sedimente. Boat traffic correlated with up to 50% increases in turbidity. Resuspension of sediments by boats is likely to occur across 56% of the lake area. Benthic sediment resuspension may contribute to the suppression of fish and macrophyte communities, domination of the phytoplankton community by Cyanobacteria, suspension of toxic ammonia, and increased restoration time-scales. |
| Stirring up Trouble? Resuspension of Bottom Sediments by Recreational Watercraft | M. M. Beachler; D. F. Hill | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | 15 - 25 | Stirring up Trouble? Resuspension of Bottom Sediments by Recreational Watercraft Authors: M. M. Beachlera; D. F. Hilla Abstract An experimental and theoretical study of the hydrodynamic impacts of recreational watercraft in shallow water bodies is presented. Of particular interest is the ability of turbulent prop or jet wash to resuspend bottom sediments. Intuition suggests, and the experiments confirm, that this ability is a strong function of boat speed and water depth. The results of this study demonstrate that boats operating at high speed have no greater impact on the lake bed than boats travelling at idle speeds. The greatest impact is seen when boats are travelling at 'near-plane' speeds. This critical speed is a function of boat size and water depth. To increase the usefulness of the observations, a theoretical model of the flow underneath a passing boat was developed and validated with the data. Relying on only a few input parameters, the model can be used to estimate, for example, the minimum operating depth required for a given boat to prevent sediment resuspension. Discussion of the relevance of this work in the context of setting use restrictions for watercraft is provided. Keywords: boating; recreational conflicts; sediment resuspension; hydrodynamics View Full Text ArticleSubscribe Affiliation: a Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA DOI: 10.1080/07438140309353985 Published in: Lake and Reservoir Management, Volume 19, Issue 1 March 2003 , pages 15 - 25 Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: | An experimental and theoretical study of the hydrodynamic impacts of recreational watercraft in shallow water bodies is presented. Of particular interest is the ability of turbulent prop or jet wash to resuspend bottom sediments. Intuition suggests, and the experiments confirm, that this ability is a strong function of boat speed and water depth. The results of this study demonstrate that boats operating at high speed have no greater impact on the lake bed than boats travelling at idle speeds. The greatest impact is seen when boats are travelling at 'near-plane' speeds. This critical speed is a function of boat size and water depth. To increase the usefulness of the observations, a theoretical model of the flow underneath a passing boat was developed and validated with the data. Relying on only a few input parameters, the model can be used to estimate, for example, the minimum operating depth required for a given boat to prevent sediment resuspension. Discussion of the relevance of this work in the context of setting use restrictions for watercraft is provided. |
| Managing Recreational Use on the Yahara Lakes | Susan A. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | 35 - 44 | Managing Recreational Use on the Yahara Lakes Author: Susan A. Jonesa Abstract Conflict between water recreation users is a universal problem that is likely to become worse. Dane County, located in southern Wisconsin, has experienced growth in recreational use and increased perception of user conflict that mirror national trends. The Yahara River chain of lakes includes the County's four largest lakes, which provide more than 7400 ha (18,000 acres) of water easily accessible to residents of this, the fastest growing county in Wisconsin. This paper describes and evaluates Dane County's experiences with, and strategies for balancing the interests of increasing number of different activities using the same resources. Users have identified wakes from other boats, lack of courtesy, excessive speed, crowding, and inconsiderate behavior as problems. Dane County's recreation management efforts described in the paper include a200-ft(61 m)slow-no-wake regulation, coupled with state boating safety and equipment rules. Educational initiatives include formal boater safety education classes, and outreach materials and maps developed by the Dane County Lakes and Watershed Commission. Future management efforts need to solicit input from all types of recreational users, focus educational efforts on recreational use impacts on aquatic ecosystems as well as the regulations themselves, and use a deliberate planning process that could resolve recreational conflicts and bring about balanced resource use. Keywords: Yahara River; water recreation management; boating regulations; boater education; user conflicts; Dane County; Dane County Lakes and Watershed Commission; Wisconsin View Full Text ArticleSubscribe Affiliation: a Dane County Lakes and Watershed Commission, Madison, WI, USA DOI: 10.1080/07438140309353987 Published in: Lake and Reservoir Management, Volume 19, Issue 1 March 2003 , pages 35 - 44 Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: PDF (English) | Conflict between water recreation users is a universal problem that is likely to become worse. Dane County, located in southern Wisconsin, has experienced growth in recreational use and increased perception of user conflict that mirror national trends. The Yahara River chain of lakes includes the County's four largest lakes, which provide more than 7400 ha (18,000 acres) of water easily accessible to residents of this, the fastest growing county in Wisconsin. This paper describes and evaluates Dane County's experiences with, and strategies for balancing the interests of increasing number of different activities using the same resources. Users have identified wakes from other boats, lack of courtesy, excessive speed, crowding, and inconsiderate behavior as problems. Dane County's recreation management efforts described in the paper include a200-ft(61 m)slow-no-wake regulation, coupled with state boating safety and equipment rules. Educational initiatives include formal boater safety education classes, and outreach materials and maps developed by the Dane County Lakes and Watershed Commission. Future management efforts need to solicit input from all types of recreational users, focus educational efforts on recreational use impacts on aquatic ecosystems as well as the regulations themselves, and use a deliberate planning process that could resolve recreational conflicts and bring about balanced resource use. |
| Personal Watercraft and Boats: Coastal Conflicts With Common Terns | Joanna Burger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | 26 - 34 | Personal Watercraft and Boats: Coastal Conflicts With Common Terns Author: Joanna Burgera Abstract Human disturbance to nesting colonial birds has increased with the massive development of coastal regions and rapid improvement in technology of watercraft. Disturbance to nesting common terns (Sterna hirundo) by boats was examined over a five-year period, with different degrees of management of personal watercraft (PWC) activities. In the five years before this study, reproductive success had declined to zero, perhaps due to excessive personal watercraft activity. Terns responded with significantly more upflights to PWCs that raced by and circled the island, than to motor boats that travelled slowly and remained in the channel. Public meetings and an educational campaign were successful in decreasing the percent of PWCs that raced and ran around die island, which in turn decreased die number of tern upflights and increased reproductive success. Without continued public meetings and education, PWCs began to race around the island, and the terns responded by moving from island edges to central areas that were lower and vulnerable to tidal flooding. In the following year, designated areas for rental PWC use were established, which again decreased the PWC traffic, allowing the birds to nest on the island edges. All management practices increased reproductive success, but a combination of education, public meetings, increased signage, enforcement, and designated zones for PWCs resulted in the greatest increase in reproductive success. Involving stakeholders in the process allowed people and birds to coexist, but continued vigilance and public education were essential to successful management. Keywords: disturbance; terns; personal watercraft; boats; coastal; conservation; co-management View Full Text ArticleSubscribe Affiliation: a Division of Life Sciences and Consortium for Risk Evaluation with Stakeholder Participation, Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ DOI: 10.1080/07438140309353986 Published in: Lake and Reservoir Management, Volume 19, Issue 1 March 2003 , pages 26 - 34 Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: | Human disturbance to nesting colonial birds has increased with the massive development of coastal regions and rapid improvement in technology of watercraft. Disturbance to nesting common terns (Sterna hirundo) by boats was examined over a five-year period, with different degrees of management of personal watercraft (PWC) activities. In the five years before this study, reproductive success had declined to zero, perhaps due to excessive personal watercraft activity. Terns responded with significantly more upflights to PWCs that raced by and circled the island, than to motor boats that travelled slowly and remained in the channel. Public meetings and an educational campaign were successful in decreasing the percent of PWCs that raced and ran around die island, which in turn decreased die number of tern upflights and increased reproductive success. Without continued public meetings and education, PWCs began to race around the island, and the terns responded by moving from island edges to central areas that were lower and vulnerable to tidal flooding. In the following year, designated areas for rental PWC use were established, which again decreased the PWC traffic, allowing the birds to nest on the island edges. All management practices increased reproductive success, but a combination of education, public meetings, increased signage, enforcement, and designated zones for PWCs resulted in the greatest increase in reproductive success. Involving stakeholders in the process allowed people and birds to coexist, but continued vigilance and public education were essential to successful management. |
| Trophic State, Seasonal Patterns and Empirical Models in South Korean Reservoirs | John R. Jones; Matthew F. Knowlton; Kwang-Guk An | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 19 | 1 | 2003 | 64 - 78 | Trophic State, Seasonal Patterns and Empirical Models in South Korean Reservoirs Authors: John R. Jonesa; Matthew F. Knowltona; Kwang-Guk Anb Abstract Data from 59 reservoirs in South Korea, sampled monthly during 1993-2000, showed that about one-third were mesotrophic, nearly one-half were eutrophic and the remainder were hypereutrophic based on conventional criteria for total phosphorus (TP), chlorophyll (Chi) and Secchi depth. Most reservoirs had >1 mg L-1 total nitrogen (TN) resulting in high mass ratios of TN:TP (range 23 to 243, median 76) relative to many temperate lakes. To compensate, conventional TN criteria were provisionally adjusted upward by about 2.5-times to classify Korean reservoirs uniformly across all trophicstate metrics. During die summer monsoon, TP and TN typically peaked in mesotrophic reservoirs and declined in the hypereutrophic group. The inference is that monsoon inflow produces these patterns by increasing non-point external inputs mat dominate the nutrient budgets of mesotrophic reservoirs while diluting point-source inputs important in hypereutrophic impoundments. Eutrophic reservoirs showed both response patterns, so that taken in aggregate a seasonal response was not apparent. The log relation between Chl and TP was linear and showed an average yield of Chl per unit of TP on par with other temperate lakes. Seasonally, die Chl-TP relation was strongest during summer and weaker during fall-winter which is consistent with increased light-limitation during mixis in these monomictic impoundments. Seasonal development of Chl did not show strong evidence of a spring or fail bloom. About half of the time maximum Chl values were measured during the monsoon or post-monsoon (July-September). Maximum Chl was ~3 times the annual mean and during summer maximum Chl was ~ double the mean. The log relation between Chl and Secchi depth matched mat found in North American lakes and the seasonal phenology for Secchi depth was die opposite of Chl and suspended solids. The analysis confirms that die monsoon is a major source of variation within and among Korean reservoirs. Keywords: Korea; trophic state; monsoon; nutrients; chlorophyll; transparency; seasonal patterns View Full Text ArticleSubscribe Affiliations: a Department of Fisheries and Wildlife Sciences, University of Missouri, Columbia, MO b Department of Environmental Science and Engineering, Ewha Womans University, Seoul, Republic of Korea DOI: 10.1080/07438140309353991 Published in: Lake and Reservoir Management, Volume 19, Issue 1 March 2003 , pages 64 - 78 Publication Frequency: 4 issues per year First Published on: 01 March 2003 Formats available: PDF (English) | Data from 59 reservoirs in South Korea, sampled monthly during 1993-2000, showed that about one-third were mesotrophic, nearly one-half were eutrophic and the remainder were hypereutrophic based on conventional criteria for total phosphorus (TP), chlorophyll (Chi) and Secchi depth. Most reservoirs had >1 mg L-1 total nitrogen (TN) resulting in high mass ratios of TN:TP (range 23 to 243, median 76) relative to many temperate lakes. To compensate, conventional TN criteria were provisionally adjusted upward by about 2.5-times to classify Korean reservoirs uniformly across all trophicstate metrics. During die summer monsoon, TP and TN typically peaked in mesotrophic reservoirs and declined in the hypereutrophic group. The inference is that monsoon inflow produces these patterns by increasing non-point external inputs mat dominate the nutrient budgets of mesotrophic reservoirs while diluting point-source inputs important in hypereutrophic impoundments. Eutrophic reservoirs showed both response patterns, so that taken in aggregate a seasonal response was not apparent. The log relation between Chl and TP was linear and showed an average yield of Chl per unit of TP on par with other temperate lakes. Seasonally, die Chl-TP relation was strongest during summer and weaker during fall-winter which is consistent with increased light-limitation during mixis in these monomictic impoundments. Seasonal development of Chl did not show strong evidence of a spring or fail bloom. About half of the time maximum Chl values were measured during the monsoon or post-monsoon (July-September). Maximum Chl was ~3 times the annual mean and during summer maximum Chl was ~ double the mean. The log relation between Chl and Secchi depth matched mat found in North American lakes and the seasonal phenology for Secchi depth was die opposite of Chl and suspended solids. The analysis confirms that die monsoon is a major source of variation within and among Korean reservoirs. |
| Development and Application of Hydrologic Restoration Goals for a Large Subtropical Lake | Karl E. Havens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 4 | 2002 | 285 - 292 | Development and Application of Hydrologic Restoration Goals for a Large Subtropical Lake Author: Karl E. Havensa Abstract During planning for the Comprehensive Everglades Restoration Program (CERP), ecosystem conceptual models were used to develop hydrologic restoration goals for Lake Okeechobee, a large multi-purpose lake at the center of the regional ecosystem. The models were based on observational and experimental research, and the goals were used to evaluate alternative restoration plans. Results were integrated with those from several other parts of the regional system. A best overall plan was selected, and the United States Congress authorized the CERP in 2000. In Lake Okeechobee, the CERP is expected to reduce the occurrence of damaging high and low water levels, and increase the occurrence of spring water level recessions that benefit native biota. Ecosystem conceptual models will continue to be and used as a framework for long-term adaptive assessment during CERP implementation. The overall approach represents an effective integration of science and resource management. Keywords: lake restoration; ecosystem conceptual models; hydrologic goals View Full Text ArticleSubscribe Affiliation: a South Florida Water Management District, West Palm Beach, Florida, USA DOI: 10.1080/07438140209353934 Published in: Lake and Reservoir Management Publication Frequency: 4 issues per year First Published on: 01 December 2002 Formats available: | During planning for the Comprehensive Everglades Restoration Program (CERP), ecosystem conceptual models were used to develop hydrologic restoration goals for Lake Okeechobee, a large multi-purpose lake at the center of the regional ecosystem. The models were based on observational and experimental research, and the goals were used to evaluate alternative restoration plans. Results were integrated with those from several other parts of the regional system. A best overall plan was selected, and the United States Congress authorized the CERP in 2000. In Lake Okeechobee, the CERP is expected to reduce the occurrence of damaging high and low water levels, and increase the occurrence of spring water level recessions that benefit native biota. Ecosystem conceptual models will continue to be and used as a framework for long-term adaptive assessment during CERP implementation. The overall approach represents an effective integration of science and resource management. |
| Water-level Management as a Tool for the Restoration of Shallow Lakes in the Netherlands | Hugo Coops; S. Harry Hosper | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 4 | 2002 | 293 - 298 | Water-level Management as a Tool for the Restoration of Shallow Lakes in the Netherlands Authors: Hugo Coopsa; S. Harry Hospera Abstract Water-level fluctuations are among the major driving forces for shallow lake ecosystems. In the low-lying parts of the Netherlands, the water-level regime of lakes is strictly regulated. This is needed for reducing risks of flooding and economic purposes, including maximum agricultural benefit. The fixation of water levels has had a severe impact on the functioning of (semi-)aquatic ecosystems. We review the benefits of natural water-level fluctuations, considering the impacts on nutrient inputs, nutrient concentrations, phytoplankton development and turbidity. In particular, the mediating role of submersed and emergent vegetation and filter feeders is addressed. The present government policy, to allow more space for water, presents a major challenge for combining flood prevention measures and ecological restoration. Restoration of natural water-level regimes, which is likely to lead to enhancement of water quality and biodiversity, may occur in two ways: (1) expanding the critical limits between which the water level is allowed to fluctuate annually, and/or (2) incidental recessions of the water level. It is stressed that ecologically-based water-level regimes should be incorporated into the context of multiple use of lakes. Keywords: lake restoration; water-level fluctuations; water management View Full Text ArticleSubscribe Affiliation: a RIZA, AA Lelystad, the Netherlands DOI: 10.1080/07438140209353935 Published in: Lake and Reservoir Management, Volume 18, Issue 4 December 2002 , pages 293 - 298 Publication Frequency: 4 issues per year First Published on: 01 December 2002 Formats available: | Water-level fluctuations are among the major driving forces for shallow lake ecosystems. In the low-lying parts of the Netherlands, the water-level regime of lakes is strictly regulated. This is needed for reducing risks of flooding and economic purposes, including maximum agricultural benefit. The fixation of water levels has had a severe impact on the functioning of (semi-)aquatic ecosystems. We review the benefits of natural water-level fluctuations, considering the impacts on nutrient inputs, nutrient concentrations, phytoplankton development and turbidity. In particular, the mediating role of submersed and emergent vegetation and filter feeders is addressed. The present government policy, to allow more space for water, presents a major challenge for combining flood prevention measures and ecological restoration. Restoration of natural water-level regimes, which is likely to lead to enhancement of water quality and biodiversity, may occur in two ways: (1) expanding the critical limits between which the water level is allowed to fluctuate annually, and/or (2) incidental recessions of the water level. It is stressed that ecologically-based water-level regimes should be incorporated into the context of multiple use of lakes. |
| Linking Science with Management of Freshwater Systems | Karl E. Havens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 4 | 2002 | iii | | |
| Setting Flow Levels for Controlling Cyanobacterial Blooms in Tropical Weir Pools | Myriam Bormans; Phillip Ford | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 4 | 2002 | 275 - 284 | Setting Flow Levels for Controlling Cyanobacterial Blooms in Tropical Weir Pools | Toxic cyanobacterial blooms occur frequently in water supply weir pools and storages in tropical Australia and elsewhere. They flourish under warm stratified conditions and their amelioration and management is an ongoing problem. We investigated bloom occurrence and growth in 3 separate water storages on the Fitzroy River in Queensland, Australia. We show that there is an opportunity to reduce its prevalence by manipulation of the riverine flow to remove the stratification, and to raise the turbidity through the resuspension of the finely divided bottom sediments. These effects are not due solely to flushing the weirs but to “resetting†the optical and mixing depths so that conditions are inimical to buoyant cyanobacteria. The persistence of the sediment particles in the water column, and the size of the discharge are the two most important factors in determining the effectiveness of the procedure. |
| Managing Taste and Odor Problems in a Eutrophic Drinking Water Reservoir | Val H. Smith; Jonathan Sieber-Denlinger; Frank deNoyelles Jr.; Scott Campbell; Shugen Pan; Stephen J. Randtke; Gerald T. Blain; Vernon A. Strasser | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 4 | 2002 | 319 - 323 | Managing Taste and Odor Problems in a Eutrophic Drinking Water Reservoir | Drinking water for the City of Wichita, KS is provided by Cheney Reservoir, a eutrophic impoundment constructed by the U.S. Bureau of Reclamation in 1962. This large, shallow reservoir has a mean depth of 5.3 meters and a surface area of 40 km2. Numerous reports of undesirable taste and odor in drinking water were received by the City of Wichita Water and Sewer Department in the early 1990's, and periodic episodes of objectionable tastes and odor have occurred up through fall 2001. An intensive limnological sampling program was carried out from August 1999-October 2000, and simultaneous measurements of two taste and odor-causing compounds (geosmin and methylisoborneol) in the lakewater were also performed. These data were used to construct empirical, phosphorus-based water quality management recommendations designed to help reduce the likelihood of objectionable taste and odor events in Cheney Reservoir. The general framework developed here should also be applicable to other waterbodies exhibiting taste and odor-related problems. |
| Growth of Calcareous Epilithic Mats in the Margin of Natural and Polluted Hydrosystems: Phosphorus Removal Implications in the C–111 Basin, Florida Everglades, USA | Serge Thomas; Evelyn E. Gaiser; Miroslav Gantar; Aga Pinowska; Leonard J. Scinto; Ronald D. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 4 | 2002 | 324 - 330 | Growth of Calcareous Epilithic Mats in the Margin of Natural and Polluted Hydrosystems: Phosphorus Removal Implications in the C-111 Basin, Florida Everglades, USA | The Florida Everglades is a fragile wetland system that is naturally depleted in phosphorus (P). This hydrosystem has been heavily impacted by human activities, including the draining of wetlands to provide water for agricultural and urban use. The result is a highly compartmentalized system with altered hydropatterns; wetlands receive canal discharges from diffuse agricultural/urban runoff containing high levels of pollutants, including P. Excess loading of P has induced ecological changes, including dramatic effects on periphyton, the dominant producer community. An Everglades rehabilitation plan has been established to restore natural hydropatterns and decrease P loads. On the southern edge of a large canal (C-111) draining the southern Everglades, levees have been removed to rehabilitate hydrology in the adjacent marsh. Levee removal resulted in exposure of limestone bedrock that, when flooded with shallow water from the canal, favors the development of thick calcareous epilithic mats. When flooded approximately 6 months a year, this margin area between the polluted and the natural hydrosystem functions as a Periphyton-based Stormwater Treatment Area(PSTA), a biological tool developed at the Southeast Environmental Research Center (Miami, FL), being considered in the Everglades as a means of P removal from enriched waters. Here, we evaluate the harvesting rates of periphyton that promote the most efficient removal of TP from the water entering the marsh. Results indicate that harvesting of periphyton at 3 month intervals provides the greatest TP sequestration. |
| Quantification of Oxygen Depletion in Lakes and Reservoirs with the Hypoxic Factor | Gertrud K. Nürnberg | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 4 | 2002 | 299 - 306 | Quantification of Oxygen Depletion in Lakes and Reservoirs with the Hypoxic Factor | The amount of dissolved oxygen (DO) in lake water has biological and chemical implications. There are no easy ways to quantify exeedences of important thresholds of DO in lakes, except the complete lack of DO, quantified as an annual or seasonal anoxic factor (Nrnberg 1995a, b). Here an analogous concept, the “Hypoxic Factor†(HF) is introduced. According to specific water quality standards, certain levels of oxygen depletion can be quantified, e.g., DO concentrations below 5 mg L-1 or 6.5 mg L-1. The HF is computed from the duration and extent of hypoxia by using DO profiles and hypsographic data. It is expressed in such a way that a value of 365 d yr-1 would mean the whole lake has a DO concentration below the specified level at all times. The application to a TMDL project, where DO standards are to be employed in a large Snake River reservoir, demonstrates the potential usefulness of HF. This quantification of hypoxia allows the testing of hypotheses, e.g., the dependency of hypoxia on stage height, flow and nutrients. Significant relationships were found between annual expressions of hypoxia and hydrological variables (seasonal flows, water retention time) and a climatic index. |
| Watershed Impacts of Logging and Wildfire: Case Studies in Canada | Bernadette Pinel-Alloul; Ellie Prepas; Dolors Planas; Robert Steedman; Théo Charette | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 4 | 2002 | 307 - 318 | Watershed Impacts of Logging and Wildfire: Case Studies in Canada | In Canada, disturbance of boreal forests has increased due to expanding anthropogenic activities, particularly forestry. A first attempt was made to evaluate impacts of forest harvesting and wildfire on changes in water quality and biota of lakes. We present case studies in two major geological and climatic subregions of the boreal ecozone in Canada: the Boreal Plain and the Boreal Shield. Responses of lake ecosystems to wildfire and logging differed. In upland Boreal Plain lakes, total phosphorus (P), inorganic nitrogen (N) and algal biomass were higher in lakes with burned watersheds, whereas, only total P increased in lakes with watershed logging. Logging on the Boreal Shield and wildfire in wetland-and permafrost-dominated watersheds on the northern Boreal Plain were associated with increases in dissolved organic carbon (DOC) and water colour, possibly causing light-limitation of algae in both regions, and a decrease in calanoid biomass in eastern Boreal Shield lakes. The number of water quality indicators affected by watershed disturbances was greater in the oligotrophic ecosystems of the Boreal Shield. The nutrient response of disturbed lakes was strongly related to lake drainage ratios: lakes with high drainage ratios had the strongest response to disturbance. Effects were also dependent on climate, wetland coverage, and regional lake characteristics. Morphometric, chemical, and biological indicators are recommended to monitor natural and anthropogenic watershed disturbances of aquatic ecosystems in Canada's Boreal forest. |
| Development of a Total Phosphorus Concentration Goal in the TMDL Process for Lake Okeechobee, Florida (USA) | Karl E. Havens; William W. Walker Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 3 | 2002 | 227 - 238 | Development of a Total Phosphorus Concentration Goal in the TMDL Process for Lake Okeechobee, Florida (USA) | This paper describes the approach used to establish an in-lake concentration goal for total phosphorus in the total maximum daily load (TMDL) process carried out by die Florida Department of Environmental Protection (FDEP) for Lake Okeechobee. In order to specify the in-lake phosphorus goal, the first consideration was to identify the most suitable indicator of “imbalance in flora or fauna†pursuant to Subsection 62-302.530(48)(b) of the Florida Administrative Code (FAC). Blooms of cyanobacteria (blue-green algae) were previously identified as one of the most serious symptoms of cultural eutrophication in this lake, and there existed a large data set relating total phosphorus to chlorophyll a, which can be used to index the occurrence of blooms. We evaluated the occurrence of samples with chlorophyll a in excess of 40 μg·L-1 (moderate bloom) and 60 μg·L-1 (severe bloom) as a function of total phosphorus concentrations in order to specify the lake phosphorus goal. A cross-tabulation procedure was used to identify a range of total phosphorus corresponding to a rapid increase in bloom frequency. Near-shore and pelagic data sets were sorted by total phosphorus and each was sub-divided into ten intervals of approximately equal sample size. When total phosphorus averaged below 30 μg·L-1, the probability of moderate blooms was below 3% and the probability of severe blooms was near 1% in the near-shore region. When total phosphorus averaged between 35 and 45 μg·L-1, frequencies were between 15 and 35% for moderate blooms and between 2 and 5% for severe blooms, respectively. Pelagic bloom frequencies also increased with increasing phosphorus, but the response was considerably muted relative to that observed in the near-shore area. To ensure an acceptable level of risk in terms of algal bloom occurrence, a total phosphorus goal of 40 μg·L-1 was selected by the FDEP. Mass-balance modeling results (Walker 2000) indicate that an average external phosphorus load of 140 metric tons y1 (compared to a 1973 to 1999 mean of 498 metric tons y1) would provide a long-term average phosphorus concentration in the lake's pelagic zone of 40 μg·L-1. Based on our empirical model relating bloom frequencies to total phosphorus, it is predicted that under these TMDL loading conditions, bloom frequencies in the near-shore region would be 2 to 9%, as compared to 5 to 33% under present conditions. Successful implementation of the TDML should significantly reduce near-shore bloom frequencies in Lake Okeechobee. |
| Trophic Changes in Otsego Lake, NY Following the Introduction of the Alewife (Alosa psuedoharengus) | Willard N. Harman; Matthew F. Albright; David M. Warner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 3 | 2002 | 215 - 226 | Trophic Changes in Otsego Lake, NY Following the Introduction of the Alewife (Alosa psuedoharengus) | Changes at several trophic levels in Otsego Lake from the 1930s to present are described relative to changes in the planktivorous fish community. Prior to the late 1980s, cisco (Coregonus artedi) was the dominant planktivore. The alewife (Alosa pseudoharengus) appeared in 1986 and subsequently became dominant. Two patterns emerged when we contrasted the pelagic flora and fauna under those two dominant planktivore populations. When cisco were the primary planktivores, cladoceran size and biomass was significantly greater in the epilimnion (primarily Daphnia pulex) than in the hypolimnion (primarily Bosmina coregoni). Phytoplankton were dominated by net and large nannoplankton (>0.03 mm), withcyano bacteria uncommon until late summer. From 1973-1988, mean summer chlorophyll a was 2.3±1.2 (S.D.) μg·L-1 (range 0.68-4.2). Mean summer Secchi transparency was 5.2 ± 0.5 m (range 3.8-7.8). Areal hypolimnetic oxygen deficits (AHOD; a measure of oxygen consumption during periods of stratification) were 0.076-0.080 mg cm-2 day-1. Since alewife have dominated, Daphnia have become rare in the lake. Mean cladoceran size in the epilimnion and hypolimnion (essentially all Bosmina) is much more uniform and reduced from prior size distributions. Phytoplankton abundance has increased, as has the mean summer chlorophyll a (6.4 ±1.5 S.D ug·L-1, range 3-8.7). The dominant algae are now smaller nannoplankton (< 0.03 mm) and cyanobacteria. Mean summer Secchi transparency decreased substantially to 3.2 ± 0.3 m (range 2.5-4.0) and AHOD increased (range 0.090-0.102 mg cm-2 day1). Whitefish (Coregonus clupeaformis) and cisco have declined, while lake trout (Salvelinus namycush)have increased. All changes have occurred despite significant efforts to reduce non-point source nutrient loading to the lake. While the establishment of alewives has enhanced the production of Otsego Lake's salmonid fishery to date, it has increased the challenge to those interested in managing the lake in an ecologically sustainable manner. |
| Movements of Displaced Largemouth Bass in Two Indiana Natural Lakes | Jed Pearson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 3 | 2002 | 257 - 262 | Movements of Displaced Largemouth Bass in Two Indiana Natural Lakes | Movements of largemouth bass Micropterus salmoides that were displaced within and between two inter-connected natural lakes in Indiana were monitored to determine if they would return to their capture locations. Nine largemouth bass were captured by angling and electro fishing at Lake Wawasee and surgically fitted with ultrasonic transmitters. Five bass (experimentals) were then displaced 3.1-8.1 km downstream into Syracuse Lake. For comparison, four bass (controls) were released in Lake Wawasee, two displaced (2.4 and 3.6 km) and two released at their capture sites. Locations of bass were determined over a 15-month period. Only one experimental bass returned to Lake Wawasee and the area where it was captured. One experimental bass was removed from the channel between the lakes by an angler, another bass failed to return and either died or shed its transmitter in Syracuse Lake, and two experimental bass were last located within Syracuse Lake before contact was lost. The two control bass displaced within Lake Wawasee returned to their capture areas, while the two control bass released at their capture sites remained in those vicinities and moved shorter distances than displaced fish. Experimental fish were tracked during 11-348 d, compared to 77-452 d for control fish, possibly reflecting greater survival of the latter. The results of this study should encourage largemouth bass tournament organizers and fishery managers to adopt measures to reduce inter-lake displacement of angler-caught fish. |
| Limnological and Statistical Issues for Monitoring the Impact of a Lake Source Cooling Facility: Cayuga Lake, NY | David A. Matthews; Stephen V. Stehman; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 3 | 2002 | 239 - 256 | Limnological and Statistical Issues for Monitoring the Impact of a Lake Source Cooling Facility: Cayuga Lake, NY | Limnological data collected for two years at nine sites in the southern end of Cayuga Lake, NY, before the start-up of a cooling water facility (summer 2000), are analyzed to identify appropriate measures of trophic state and estimate the capability of a monitoring program to identify changes associated with the operation of this facility. The concentration of chlorophyll a (Chl) is found to be the preferred indicator of trophic state. The concentration of total phosphorus and clarity are compromised as trophic indicators in this system because of the contributions of inanimate particles (tripton) to these measures associated with the hydrology and morphometry of the lake and the occurrence of the whiting phenomenon. A Before-After-Control-Impact design is used to assess the ability of the monitoring program to detect potential impacts associated with operation of the cooling water facility. Statistical power analyses conducted with the preoperational monitoring data indicate the current bi-weekly sampling program will detect a 30% change in Chl with a probability of 0.7. Attributing causation of any future change in Chi coincident with the start-up and operation of the cooling water facility is problematic because of potential confounding effects associated with variation in phosphorus loading from wastewater treatment facilities, natural variation in meteorological conditions, and water quality changes associated with zebra mussel populations. |
| Whole Lake Fluridone Treatments For Selective Control of Eurasian Watermilfoil: I. Application Strategy and Herbicide Residues | Kurt D. Getsinger; John D. Madsen; Tyler J. Koschnick; Michael D. Netherland | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 3 | 2002 | 181 - 190 | Whole Lake Fluridone Treatments For Selective Control of Eurasian Watermilfoil: I. Application Strategy and Herbicide Residues | The herbicide fluridone is being used in northern lakes and reservoirs to control the exotic species Eurasian watermilfoil (Myriophyllumspicatum L.). Since quantitative information linking changes in plant communities following fluridone applications is limited, particularly with respect to water residue records, a study was conducted to investigate the effect of low-dose treatments on the submersed plant communities in four Michigan lakes. The overall study objective was to determine whether plant species diversity and frequency of occurrence were affected by low-dose fluridone applications in the year of treatment. The primary objective of this portion of the overall study was to provide an application strategy that would maintain a threshold dose of fluridone, 5 μg·L-1 declining to 2 μg·L-1, in the treated lakes to selectively control Eurasian watermilfoil. Study lakes were 55 to 220 ha in size and contained an average of nine species of submersed plants. Big Crooked, Camp, Lobdell, and Wolverine lakes were treated in mid-May 1997 with the formulation Sonar® AS, to yield an initial concentration of 5 μg·L-1 fluridone in the upper 3.05 m of each lake. Asequential application of Sonar® AS was conducted on each lake at 16 to 21 days after initial treatment (DAIT), intended to reestablish a fluridone concentration of 5 μg·L-1 in the upper 3.05 m of each lake. Bass, Big Seven, Clear, and Heron lakes received no fluridone applications and served as untreated reference sites. Water residue samples were collected at prescribed intervals on each fluridone-treated lake from pretreatment up to 81 DAIT. Samples were collected from six littoral stations and from two deep locations throughout each lake, and temperature profiles were measured at the deep stations. Fluridone residues were analyzed using two separate techniques, the newly developed enzyme-linked immunosorbent assay and the standard high performance liquid chromatography method. Fluridone levels on three of the treated lakes met the laboratory-derived criteria for achieving good control of Eurasian watermilfoil by providing a peak concentration of approximately 5 μg·L-1 during the first 2 weeks posttreatment, and by main taininga concentration >2 μg·L-1 through 60 DAIT. Residues became well mixed in the water column under isothermal conditions, and thermal stratification prevented mixing of fluridone into deeper and colder waters. Residue data indicated that thermal stratification, or the lack thereof, at the time of herbicide application can affect target herbicide concentrations. Using the volume of a pre-selected depth zones to calculate the amount of fluridone needed to achieve a particular target concentration can result in an over- or under-dosing of a water body. |
| Reservoir Zones: Microbial Production and Trophic State | Owen T. Lind | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 3 | 2002 | 263 - 271 | Reservoir Zones: Microbial Production and Trophic State | It is hypothesized that differences in the trophic states of three reservoir zones - riverine, transition, and lacustrine; i.e., change through space, can provide insights into the general eutrophication of the system; i.e., change through time. Differences in phyto-and bacterioplankton dynamics among the zones of reservoirs are explored. Microbial dynamics described for the eutrophication of natural lakes are taken as a null hypothesis against which reservoir zones are compared. Factors capable of affecting microbial community composition, production, metabolism and biomass accumulation are evaluated in the different zones. The lack of sufficient reservoir data on microbial processes, and particularly those of the bacterioplankton, prevents the shaping of comprehensive reservoir zone microbial models. The hypotheses posed provide a guide for much-needed reservoir research. |
| Sedimentological Effects of Aeration-Induced Lake Circulation | Daniel R. Engstrom; David I. Wright | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 3 | 2002 | 201 - 214 | Sedimentological Effects of Aeration-Induced Lake Circulation | Multiple sediment cores were collected from each of ten Minnesota lakes (five aerated and five non-aerated) to evaluate the long-term effects of aeration-induced circulation on sediment accumulation and composition. Coring sites for each basin were widely spaced at different depths to encompass a range of depositional environments, and sediments were dated by 210Pb methods. All lakes, aerated and non-aerated, show an increase in sediment accumulation commencing around the time of European settlement in the region (c. 1880). At the same time, sedimentary organic content decreases by 5-40% in all but three lakes due to increased inputs of silts and clays from erosion of catchment soils. Sediment accumulation rates do not decline with the onset of aeration in any of the aerated lakes, but in most cases remain near maximum values to the present day. A recent decrease in sediment flux, evident in one non-aerated lake, was driven by land-use changes in the catchment that decreased nutrient and sediment loading. Sedimentary organic content does not decline in any of the lakes, aerated or non-aerated, during the last two decades. Historic patterns of sediment accumulation and composition in the aerated lakes are no different from that shown by non-aerated lakes. Results from this study do not support claims that aeration-induced circulation will enhance the removal of organic sediments from lake basins either by mineralization or offshore transport. |
| Whole Lake Fluridone Treatments For Selective Control of Eurasian Watermilfoil: II. Impacts on Submersed Plant Communities | John D. Madsen; Kurt D. Getsinger; R. Michael Stewart; Chetta S. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 3 | 2002 | 191 - 200 | Whole Lake Fluridone Treatments For Selective Control of Eurasian Watermilfoil: II. Impacts on Submersed Plant Communities | The aquatic herbicide fluridone is being used in northern tier states to selectively control the submersed exotic species Eurasian watermilfoil (Myriophyllum spicatum L.) growing in lakes and reservoirs. Reliable quantitative information linking changes in the submersed plant community following fluridone applications is limited, particularly with respect to water residue records. Therefore, a study was conducted to investigate the effect of low-dose fluridone treatments on the submersed plant communities in four lakes in Michigan. The overall study objective was to determine whether submersed plant species diversity and frequency were impacted by low-dose fluridone applications in the year of treatment, when targeting a whole lake for Eurasian watermilfoil control. The primary objectives of this portion (part II) of the overall study was to determine fluridone effectiveness on the exotic submersed species Eurasian watermilfoil (Myriophyllum spicatum L.) and to evaluate shifts in plant species diversity at one year posttreatment. Secondary objectives included determining fluridone effectiveness on the exotic submersed species curlyleaf pondweed (Potamogeton crispus L.) and verifying laboratory-derived results of fluridone concentration and exposure time relationships with respect to efficacy against Eurasian watermilfoil. Quantitative sampling of vegetation was performed using point-based frequency of species occurrence to evaluate whole-lake distribution and diversity of the submersed plant community of all eight study lakes. The technique was implemented using global positioning and geographic information systems, with a minimum grid resolution of 50 m by 50 m. Plant surveys were conducted in early to mid May and in mid August in 1997 (year of treatment) and 1998 (12 and 15 months post treatment). The fluridone concentration and exposure time (CET) relationship resulted in good to excellent control of Eurasian watermilfoil through 15 months posttreatment on three of the treated lakes (Big Crooked, Camp, and Lobdell). On a fourth lake, Wolverine, the required CET relationship was not maintained and poor control of Eurasian water milfoil was observed. There was no strong evidence of long-term curlyleaf pondweed control in any of the fluridone-treated lakes. The herbicide application strategy used in this study did not significantly impact the native plant species diversity or cover in the year of treatment, or through 15 months posttreatment, in any of the fluridone-treated lakes. Native plant cover was maintained at levels >70% in the year of treatment and at one year posttreatment; a level above the range (20 to 40%) recommended for healthy fish and wildlife habitat. The selective control of Eurasian watermilfoil achieved in this study verified results from previously conducted laboratory and outdoor mesocosm evaluations. |
| Trophic State Differences in Population Characteristics of Gizzard Shad in Two Tennessee River Impoundments | Darien L. Clayton; Michael J. Maceina | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 2 | 2002 | 109 - 117 | Trophic State Differences in Population Characteristics of Gizzard Shad in Two Tennessee River Impoundments | Gizzard shad Dorosoma cepedianum population characteristics, including relative abundance, size structure, growth, body condition, and mortality were compared between Guntersville and Wheeler Reservoirs, two Tennessee River impoundments. Fish were collected with DC electrofishing and water quality was sampled along upstream to downstream longitudinal gradients in each reservoir from October 1995 through August 1996. Chlorophyll-a concentrations and gizzard shad abundance were higher in Wheeler than in Guntersville Reservoir. Neither chlorophyll-a concentrations nor gizzard shad a bundances showed a longitudinal gradient from upstream to downstream in either reservoir. However, a gradient of increasing water clarity was evident in both reservoirs that was associated with poorer gizzard shad body condition. In Guntersville Reservoir, where gizzard shad abundance was lower, the population was comprised of older and larger fish that exhibited faster growth and higher body condition. Gizzard shad were more abundant in Wheeler Reservoir, and fish displayed slower growth, poorer body condition, and potentially greater exposure time to predation. Hence, survival was lower as this population was comprised of a higher proportion of younger fish than in Guntersville Reservoir. Trophic state differences among reservoirs were related to differences in gizzard shad population characteristics and likely influenced the role of these fish as a prey species. |
| Development of a Fish Contaminant Monitoring Protocol for Lake Mead, Nevada | Shawn L. Gerstenberger; Barbara Eccleston | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 2 | 2002 | 118 - 128 | Development of a Fish Contaminant Monitoring Protocol for Lake Mead, Nevada | Fish consumption practices and patterns for Lake Mead, Nevada, were determined by administering detailed questionnaires to 150 sportsmen at the Lake Mead National Recreation Area. Striped bass, largemouth bass and channel catfish were the most frequently consumed fish species, with an average of 22 ± 3.6 fish meals a year consumed by respondents. Striped bass and largemouth bass between 13-18 inches were most commonly consumed, while channel catfish were typically between 10-15 inches in length. Skin-off fillets of all three species was the preferred method of preparation, while cooking techniques varied by species. The most popular fishing areas in our survey included Government Wash, Hemenway Harbor, Overton Beach, Saddle Cove, St. Thomas and the Las Vegas Bay (wash). Based on these data, a three fish, four location contaminant monitoring protocol was developed to best represent human exposure to contaminated fish at Lake Mead. This sampling design is applicable to large lakes and reservoirs where succinct toxicological data are needed, but standard sampling techniques would be excessively expensive or impractical. |
| Influence of a Reservoir Drawdown on Bird Use of Lake Talquin, Florida | Gary L. Sprandel; Richard L. Cailteux; David T. Cobb | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 2 | 2002 | 164 - 176 | Influence of a Reservoir Drawdown on Bird Use of Lake Talquin, Florida | We examined the effects of a reservoir drawdown on avian use of Lake Talquin in the Florida Panhandle. Observations during the drawdown of 1998 showed increased wading bird, larid, and passerine bird usage of the lake. A decline in the number of osprey (Pandion haliaetus) nests and mean brood size was also observed during the drawdown. The two years following the drawdown showed increased wading bird usage, non-significant (P > 0.05) change in osprey nest success and young-of-year sport fish numbers, and declining common moorhen (Gallinula chloropus) and lesser scaup (Aythya affinis) use compared to the two years prior to the drawdown. No significant correlation (P > 0.05) was observed between young-of-year sport fish numbers and total wading bird numbers. Post-drawdown changes may have been due to actual biotic changes in the lake, but also may have been part of larger regional or national trends. Lake managers should consider avian species along with the needs of lake front property owners and anglers when implementing a drawdown and refill schedule. |
| Phytoplankton in Boreal SubArctic Lakes Following Enhanced Phosphorus Loading from Forest Fire: Impacts on Species Richness, Nitrogen and Light Limitation | Preston McEachern; Ellie E. Prepas; Dolors Planas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 2 | 2002 | 138 - 148 | Phytoplankton in Boreal SubArctic Lakes Following Enhanced Phosphorus Loading from Forest Fire: Impacts on Species Richness, Nitrogen and Light Limitation | Forest fire in peatland environments can cause enhanced loading of coloured compounds and of phosphorus relative to nitrogen resulting in reduced light penetration and nitrogen to phosphorus ratios in lake water. To determine the potential impacts of forest fire in peatland dominated catchments, we tested nitrogen (N), phosphorus (P) and light limitation of pelagic phytoplankton with in situ microcosms in three lakes from a Boreal SubArctic ecozone. To assess if phytoplankton assemblages were influenced by water chemistry changes following fire, phytoplankton species were identified from 10 lakes in unburnt and 10 lakes in burnt catchments. In the microcosm study, P limitation and concurrent N + P limitation of phytoplankton biomass were apparent (P « 0.01) in the two lake waters representing the range of N and P concentrations for lakes in unburnt catchments. In the lake with water representative of lakes in burnt catchments, nitrogen limitation was observed (P « 0.01). Light limitation of phytoplankton biomass was observed in microcosms from one lake in a burnt and one lake from an unburnt catchment likely due to high water colour in both lake waters (> 200 mg/L [Pt]). For the 20 surveyed lakes, phytoplankton species richness was 36% lower (P « 0.01) in lakes from burnt compared to unburnt catchments. Phytoplankton communities in all lakes in this study were dominated by cyanobacteria. Phytoplankton communities in boreal forest lakes may be particularly sensitive to catchment disturbances such as fire because changes in phosphorus and carbon loading from peatlands enhance nitrogen and light limitation. |
| Phosphorus Budget and Management Strategies for an Urban Wisconsin Lake | William F. James; John W. Barko; Harry L. Eakin; Patrick W. Sorge | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 2 | 2002 | 149 - 163 | Phosphorus Budget and Management Strategies for an Urban Wisconsin Lake | Multiple external and internal phosphorus (P) sources to an urban lake, Half Moon Lake in Wisconsin, were examined during the summer of 1999 in order to develop management strategies for effective P control and reversal of eutrophication (Trophic State Index=74). Internal recycling of P accounted for 80% of the summer P budget of the lake. Flux of P from the sediment accounted for most of the internal P loading (42% of total budget). However, decomposition of Potamogeton crispus and recycling of macrophyte P during the middle of the summer growing season, and P resuspension due to motor boat activity, accounted for 20% and 17% of the P budget, respectively, representing additional important sources to be controlled. In contrast, summer P loading via the watershed (storm sewers and precipitation) was much less. Using a water quality model (Bathtub), we found that reduction of internal P sources could substantially reduce by greater than 70% the high concentrations of algae in the lake (mean summer chlorophyll = 82 mg m-3). Suggested internal P control measures included a sediment chemical treatment to bind P, greater harvesting of P. crispus to reduce the macrophyte P pool at the time of senescence, and limiting motor boat activity when the lake is weakly stratified. |
| Limnological and Loading Information and a Phosphorus Total Maximum Daily Load (TMDL) Analysis for Onondaga Lake | Steven W. Effler; Susan M. O'Donnell; David A. Matthews; Carol M. Matthews; David M. O'Donnell; Martin T. Auer; Emmet M. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 2 | 2002 | 87 - 108 | Limnological and Loading Information and a Phosphorus Total Maximum Daily Load (TMDL) Analysis for Onondaga Lake | The phosphorus (P) total maximum daily load (TMDL) analysis and associated management plan for culturally eutrophic Onondaga Lake, NY, are critically evaluated based on available input/discharge and limnological information for the system. The evaluation is based on: (1) results from a long-term monitoring program conducted on the lake, its tributaries, and the adjoining river that receives the lake's outflow, (2) algal bioassay experiments of the bioavailability of particulate P (PP) in inputs to the lake, (3) loading rate calculations for forms of P in these inputs, (4) calculations of water densities in inflows and the lake, (5) model analyses of plunging interflows and responses to seasonal material loading, and (6) mass balance calculations for a tracer conducted around the lake outlet and the receiving river to estimate inflow to the lake from the river. Several important system-specific characteristics were found not to be accommodated in the current TMDL analysis, including: (1) a P load from the river back into the lake, (2)seasonal plunging of tributaries to depths below the productive layers of the lake, (3) incomplete and different bioavailabilities of PP in the various inputs, (4) the different settling velocities of PP from these sources, (5) false high estimates of TP loading from tributaries associated with turbidity interferences in P analyses, and(6)the implications of the high flushing rate of the lake for strong seasonality in the relative impacts of externals loads. The TMDL analysis is demonstrated to understate the present role of the dominant point source and overstate the importance of non-point sources. Recommendations are made to upgrade the TMDL analysis through an integrated program of model development, testing and application, supporting process studies and monitoring, and re-evaluation of management options. |
| Reservoir Zones: Microbial Production and Trophic State | Owen T. Lind | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 2 | 2002 | 129 - 137 | Reservoir Zones: Microbial Production and Trophic State | It is hypothesized that differences in the trophic states of three reservoir zones - riverine, transition, and lacustrine; i.e., change through space, can provide insights into the general eutrophication of the system; i.e., change through time. Differences in phyto-and bacterioplankton dynamics among the zones of reservoirs are explored. Microbial dynamics described for the eutrophication of natural lakes are taken as a null hypothesis against which reservoir zones are compared. Factors capable of affecting microbial community composition, production, metabolism and biomass accumulation are evaluated in the different zones. The lack of sufficient reservoir data on microbial processes, and particularly those of the bacterioplankton, prevents the shaping of comprehensive reservoir zone microbial models. The hypotheses posed provide a guide for much-needed reservoir research. |
| Community Responses to Piscivorous Largemouth Bass: A Biomanipulation Experiment | Ray W. Drenner; Robert M. Baca; Jeffrey S. Gilroy; Mark R. Ernst; David J. Jensen; David H. Marshall | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 1 | 2002 | 44 - 51 | Community Responses to Piscivorous Largemouth Bass: A Biomanipulation Experiment | To test whether piscivorous largemouth bass (Micropterus salmoides) could be used to biomanipulate a 15-ha water supply reservoir, we assessed the effects of the addition of largemouth bass to the reservoir by monitoring the reservoir during the year before and three years after largemouth bass were stocked. A pilot study conducted in October 1990 indicated that the reservoir was eutrophic and contained a fish community dominated by zooplanktivorous threadfin shad (Dorosoma petenense) and no piscivorous fish. The reservoir was monitored during 1991 prior to stocking of largemouth bass (October 1991) and monitored in 1992, 1993 and 1994 after bass were present. Stocking of largemouth bass was successful and bass spawned in 1992, 1993 and 1994. The effects of bass cascaded down through the food web to the phytoplankton. In 1993 and 1994 the number of threadfin shad decreased, the abundance of cladocerans increased and rotifers decreased. Densities of diatoms and green algae were lower in 1992, 1993 and 1994 than in 1991. Although some phytoplankton densities decreased, blue-green algae, chlorophyll biomass, Secchi transparency, total phosphorus and total nitrogen did not change after stocking of largemouth bass and the biomanipulation was not successful in improving the reservoir's water quality. |
| Application of a Hypolimnetic Oxygen Profile Model to Lakes in Ontario | B. J. Clark; P. J. Dillon; L. A. Molot; H. E. Evans | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 1 | 2002 | 32 - 43 | Application of a Hypolimnetic Oxygen Profile Model to Lakes in Ontario | We tested a previously published empirical multivariate regression model that predicts end-of-summer oxygen concentrations in the hypolimnia of small, dilute lakes in the Boreal ecozone. The model inputs include only lake morphometry and total phosphorus concentration at spring-overturn. In this study, we tested the validity of the model using information for lakes that are larger or deeper, and have higher phosphorus concentrations than the lakes that were the basis for the original regression model. Data from 32 lakes in the Gull River watershed in central Ontario and 10 lakes in eastern Ontario were used to evaluate the model's ability to predict end-of-summer oxygen profiles. Results indicated that the original model was satisfactory for most of the 42 study lakes, but had more limited success in the deeper and larger lakes within the data set. For the eastern Ontario lake set, the original model's ability to predict oxygen in the hypolimnia was better than for the Gull River watershed lakes. It is suggested that the most useful application of the model would be to predict the change in hypolimnetic oxygen concentrations at given depths that would result from increases or decreases in total phosphorus concentrations in the lake. This would allow resource managers concerned with sportfish habitat, to estimate and assess the impact that changes in lake trophic status might have on oxygen concentrations. |
| Development, Construction, and Use of Lime and Alum Application Systems in Alberta, Canada | Mark S. Serediak; Ellie E. Prepas; Tom P. Murphy; Jay Babin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 1 | 2002 | 66 - 74 | Development, Construction, and Use of Lime and Alum Application Systems in Alberta, Canada | Between 1986 and 1993, a variety of systems, ranging from simple to complex, were designed for lime (slaked lime (Ca(OH)2) or calcite (CaCO3)) and alum (Al2(SO4)3) application to water bodies in Alberta, Canada. Application systems were used both experimentally, to determine the effectiveness of lime and alum in reducing phosphorus and algae, and commercially, for the treatment of water bodies with excessive algal and/or macrophyte growth. System designs ranged from inexpensive, easy to assemble but labour-intensive prototype models, to commercially viable, low-labour requirement systems, capable of applying chemicals to aquatic systems ranging in size from small water bodies (about 300 m2) to medium-sized lakes (about 75 ha). Results of these projects suggest that, while all systems were effective for the treatment of problem algae and macrophytes, local conditions, efficiency, and cost must determine each system's usefulness. |
| Response of an Aquatic Macrophyte Community to Fluctuating Water Levels in an Oligotrophic Lake | Tyler Wagner; C. Michael Falter | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 1 | 2002 | 52 - 65 | Response of an Aquatic Macrophyte Community to Fluctuating Water Levels in an Oligotrophic Lake | This study compares the species composition, biomass, and the influence of substrate composition on an aquatic macrophyte community in the meso-oligotrophic Lake Pend Oreille, Idaho under two winter drawdown regimes. Mean dry aquatic macrophyte biomass (AMB) in the drawdown zone (1.4 - 3.5 m) significantly increased from 39.9 gm-2 in 1990 to 99.2 gm-2 and 103.7 gm-2 with 2.1 m drawdowns in 1998 and 1999. Mean AMB deeper than 3.5 m did not significantly increase, suggesting the increased biomass in the drawdown zone can at least partially be attributed to increased winter survival. Myriophyllum sibiricum, Chara spp., and Potamogeton richardsonii were the most abundant aquatic macrophytes under the 3.5 m winter drawdown regime, while Chara spp., P berchtoldii, and P. crispus were most abundant under higher winter water levels. The exotic M. spicatum was present at one sample station and most prevalent in depths between 3.9 - 5.1 m. M. spicatum attained mean maximum densities in excess of 900 gm-2 by August, 1999 (one year after it was first observed in the lake). Logistic regression indicated a higher probability of finding clay and cobble substrates in the drawdown zone. On the clay substrates, there were significantly lower AMB (17.9 gm-2) than on sand (86.6 gm-2) or silt (129.0 gm-2) substrata with no plants observed on gravel or cobble substrata. |
| Application of the Two-Dimensional Hydrothermal and Water Quality Model, CE-QUAL-W2, to the Chesapeake Bay – Conowingo Reservoir | Patrick N. Deliman; Jeffrey A. Gerald | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 1 | 2002 | 10-19 | Application of the Two-Dimensional Hydrothermal and Water Quality Model, CE-QUAL-W2, to the Chesapeake Bay - Conowingo Reservoir | The application of the two-dimensional hydrothermal and water quality model, CE-QUAL-W2, to the Conowingo Reservoir is presented. The performance of the CE-QUAL-W2 model was enhanced with the addition of multiple particle size settling rates, and an algorithm to account for the scour process within a reservoir. The benefit of the Conowingo Reservoir to perform sediment and nutrient trapping was determined from the calculation of removal efficiencies which showed important characteristics for this reservoir which is near the end of its useful lifespan in regards to trapping capability. |
| Volunteer Lake Monitoring: Testing the Reliability of Data Collected by the Florida LAKEWATCH Program | Daniel E. Canfield Jr.; Claude D. Brown; Roger W. Bachmann; Mark V. Hoyer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 1 | 2002 | 1-9 | Volunteer Lake Monitoring: Testing the Reliability of Data Collected by the Florida LAKEWATCH Program | Because the use of volunteer samplers is a very cost-effective way to collect large amounts of information on lakes over space and time, we studied the reliability of the protocols used by the Florida LAKEWATCH program. We found that chlorophyll extractions with hot ethanol gave values that were no different from those obtained with the standard method of grinding with acetone. In a comparative study of 125 lakes we found the data collected by volunteers were comparable to those collected by professionals. Mean Secchi disk depth, TP, TN, and chlorophyll values obtained by the citizens were strongly correlated (r > 0.99) to the mean values obtained by the professionals. To determine if freezing was a valid means of preserving water samples prior to analysis, we compared estimates of chlorophyll, TP, TN, pH, total alkalinity, and specific conductance obtained from fresh samples with estimates obtained from samples frozen up to 150 days. For most lakes there was little difference in chemical measurements made in samples preserved by freezing for different lengths of time, and various statistical tests indicated that freezing was a valid means of preserving lake water samples prior to analysis. Water quality data produced by volunteer samplers following the LAKEWATCH protocols were just as good as those from samples collected by professional biologists and handled using standard methods of sample preservation. The fact that volunteers can collect credible data means that lake management agencies could amplify their limited budgets by using volunteer monitoring, to sample more lakes and to sample them more frequently. |
| Comparison of Immunoassay and HPLC for Analyzing Fluridone Concentrations: New Applications for Immunoassay Techniques | Michael D. Netherland; David R. Honnell; Alicia G. Staddon; Kurt D. Getsinger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 1 | 2002 | 75 - 80 | Comparison of Immunoassay and HPLC for Analyzing Fluridone Concentrations: New Applications for Immunoassay Techniques | High performance liquid chromatography (HPLC) and an enzyme-linked immunosorbent assay (ELISA) technique were used to analyze concentrations of the aquatic herbicide fluridone (l-methyl-3 phenyl-5-[-3 (trifluromethyl) phenyl]-4 (IH) pyridinone) in 488 surface water samples collected from two lakes in Michigan treated in 1997, 2 Michigan lakes treated in 1998, 1 lake in Florida treated in 1996, and a series of research ponds treated in Florida in 1997. Samples were collected following application of fluridone associated with operational treatment programs that targeted the exotic submersed plants Myriophyllum spicatum L. (Michigan) and Hydrilla verticillata (L.f) Royle (Florida). ELISA and HPLC results compared well (r2 = 0.84 to 0.98) across a broad range of initial fluridone treatment rates (5 to 150 μg L-1). The potential use of ELISA to monitor fluridone residues in the water in near real-time, and to use this residue data for lake specific herbicide treatment recommendations represents a unique use of ELISA technology. |
| Cyanobacterial Harmful Algal Blooms (CyanoHABs): Developing a Public Health Response | Lorraine C. Backer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 18 | 1 | 2002 | 20 - 31 | Cyanobacterial Harmful Algal Blooms (CyanoHABs): Developing a Public Health Response | Cyanobacteria, or blue-green algae, are ancient photosynthetic organisms that grow in brackish or fresh water. Species within several genera and some strains within these species produce potent toxins that can induce severe illness in animals and people. Although cyanobacterial toxins (cyanotoxins) are important environmental contaminants, public health activities are limited to emergency responses to specific poisoning events. However, more long-term public health issues, such as cyanotoxins in drinking water, have also been identified. The potential for human exposure to cyanobacterial toxins through their drinking water has been inadequately evaluated, and the public health impact from exposure to these toxins remains unknown. The response to this emerging issue will include assessing exposure, conducting epidemiologic research, and providing public health interventions. |
| Effects of Point-Source Removal on Lake Water Quality: A Case History of Lake Tohopekaliga, Florida | Vincent P. Williams | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 4 | 2001 | 315 - 329 | Effects of Point-Source Removal on Lake Water Quality: A Case History of Lake Tohopekaliga, Florida | Lake Tohopekaliga (9,840 ha) is part of the Kissimmee River system headwaters in central Florida. Point source discharges to the lake and its tributaries began in the 1950s. By the early 1960s four municipal wastewater treatment plants were discharging secondary effluent that contained high concentrations of phosphorus and nitrogen. Rapid population growth and treatment plant expansion began in the 1960s, and by 1969 the lake had experienced deterioration of water quality, aquatic habitat, and biological communities. By 1979, annual phosphorus loading to the lake was eleven times higher than under natural conditions and nitrogen loads had nearly doubled. Efforts to reduce phosphorus concentrations in effluent from the two largest point sources began in 1982, followed by complete removal of all wastewater treatment plant discharges by 1988. Ten years later, Lake Tohopekaliga had experienced reductions in total phosphorus (80 percent), ortho-phosphorus (95 percent), total nitrogen (50 percent), and chlorophyll a (30 percent). Secchi disk transparencies increased an average of 50 percent. Measurable improvements in water quality were also documented for downstream lakes Cypress, Hatchineha, and Kissimmee. No water quality changes were noted in neighboring East Lake Tohopekaliga, which served as a comparison lake for this study. |
| Seasonal Patterns of Chlorophyll a and Secchi Disk Transparency in Lakes of East-Central Minnesota: Implications for Design of Ground- and Satellite-Based Monitoring Programs | Teresa H. Stadelmann; Patrick L. Brezonik; Steven Kloiber | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 4 | 2001 | 299 - 314 | Seasonal Patterns of Chlorophyll a and Secchi Disk Transparency in Lakes of East-Central Minnesota: Implications for Design of Ground- and Satellite-Based Monitoring Programs | A data base consisting of growing-season measurements of chlorophyll a (chla) and Secchi disk transparency (SD) on lakes in the seven-county metropolitan area of the Twin Cities (Minneapolis and St. Paul, MN) was analyzed statistically to determine the consistency of seasonal patterns among lakes in the region. The data base included 370 lake-years of measurements on 145 lakes obtained between 1986 and 1997. Distinct patterns were found for both trophic variables, with maximum chla and minimum SD occurring from late July through mid-September in most lakes. Lake geometry, air temperature, and precipitation had little effect on seasonal patterns. Strong relationships (r2 values of 0.91 and 0.84) were found between average chla and maximum chla and between average SD and minimum SD for the growing season. The relationships were not affected by trophic state, lake geometry, precipitation, or temperature classes. Numbers of observations needed to estimate the growing season mean with specified relative errors were calculated for both chla and SD. Given the limitations on the frequency of data collection by both conventional means and satellite imagery, an index period of late July to mid September was found to be the optimal time to measure trophic conditions in TCMA lakes. During this period, lakes behave similarly, and in-lake variability is at a minimum for SD. Regression relationships to estimate growing season mean from 1-3 observations during this period have r2 values of 0.73-0.90 for chla and 0.83-0.90 for SD. Application of index-period lake monitoring by satellite imagery or conventional means has the potential to significantly increase the number of lakes assessed each year with minimal additional cost and effort. |
| Particulate Organic Carbon Patterns in a Mainstem Reservoir, Kentucky Lake, USA | P. M. Yurista; K. Johnston; G. Rice; G. W. Kipphut; D. S. White | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 4 | 2001 | 330 - 340 | Particulate Organic Carbon Patterns in a Mainstem Reservoir, Kentucky Lake, USA | Particulate carbon was measured spatially and temporally in the mainstem and embayments of Kentucky Lake U.S.A., the largest reservoir on the Tennessee River system. Samples were collected on pre-combusted glass fiber filters and particulate carbon and nitrogen determined with a CHN analyzer. An annual cycle was observed in the reservoir mainstem where peak particulate concentrations occurred primarily during the summer (with a yearly average 629 μg C·L-1). Concentrations of particulate carbon in embayments correlated with differential land-use practices on either side of the reservoir. Primarily agricultural western side embayments had elevated particulate carbon concentrations (1062 μg C·L-1). Forested eastern side embayments had average particulate carbon concentrations (736 μg C·L-1) that were more comparable to the mainstem. Contributions to summer POC in the reservoir mainstem were mainly from autochthonous sources, while contributions from upstream allochthonous sources were dominant during the winter. |
| Establishing Relationships Among Nutrient Concentrations, Phytoplankton Abundance, and Biochemical Oxygen Demand in Minnesota, USA, Rivers | Steven Heiskary; Howard Markus | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 4 | 2001 | 251 - 262 | Establishing Relationships Among Nutrient Concentrations, Phytoplankton Abundance, and Biochemical Oxygen Demand in Minnesota, USA, Rivers | In this study, we demonstrated significant and predictable relationships among nutrients, algae, and biochemical oxygen demand (BOD) in five medium to large Minnesota, USA, rivers. These rivers were distributed across three ecoregions ranging from the Northern Lakes & Forests (NLF) (low nutrients), to the North Central Hardwood forests (NCHF) (intermediate nutrients), to the Western Corn Belt Plains (WCBP) (high nutrients). River order varied, allowing comparisons of periphyton-dominated rivers to phytoplankton-dominated rivers. Summer flows in 1999 were significantly higher than 2000 and, as a result, the “age†of the water (residence time) was greater in 2000. The lower and more stable flows generally resulted in higher algal concentrations in 2000 as evidenced by paired comparisons between sites and years. Seston composition varied not only in terms of origin of the seston: benthic vs. planktonic, but also along a gradient of nutrient enrichment. Benthic diatoms were a significant proportion in clear, low nutrient rivers in the NLF but declined in significance in more nutrient rich NCHF rivers where planktonic green and blue-green algae became more prominent. In the more turbid and high nutrient WCBP rivers, highly tolerant blue-greens were common. Regardless of origin of the seston, rivers with high nutrients exhibited high chlorophyll and high BOD while those with low nutrients exhibited the inverse. The linkages established here will contribute to nutrient criteria development and nutrient or dissolved oxygen (DO)-based Total Maximum Daily Loading (TMDL) studies. |
| Under Ice Water Movements Induced by Mechanical surface Aeration and Air Injection | Theron G. Miller; W. C. Mackay; David T. Walty | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 4 | 2001 | 263 - 287 | Under Ice Water Movements Induced by Mechanical surface Aeration and Air Injection | We tested the hypothesis that successful lake aeration for winterkill prevention induces large-scale (whole-lake) convective flow rather than discrete aerated cells. Discrete circulating cells were not identified using mechanical surface aeration or air injection. Thermal destratification reached the most distant shorelines (up to 900 m). However, dissolved oxygen levels began to decline at about 600 m in lakes with surface aerators and at about 800 m with air injection. Vertical mixing was determined by the depth below the diffusers or surface aerators (as opposed to zmax). In addition, small depressions or distinct basins separated from the aerated basin by a shallow sill stratified and tended toward anoxia as winter progressed. Near-field velocity and dye measurements helped define zones of detrainment and entrainment near the aeration devices. These observations revealed a new conceptual model comprised of single detrainment and entrainment plumes separated by a sheer zone. |
| Dissolved Oxygen Depletion in a Small Deep Lake with a Large Littoral Zone | Omid Mohseni; Heinz G. Stefan; David Wright; Gerald J. Johnson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 4 | 2001 | 288 - 298 | Dissolved Oxygen Depletion in a Small Deep Lake with a Large Littoral Zone | Advection and its influence on water quality (density currents and the fate of transported materials, metalimnetic oxygen depletion, etc.) are well established for reservoirs and other lakes with well-defined inflows. This paper provides an example of the potential importance of these processes in small lakes with limited inflow. Viewing such lakes as one-dimensional systems may severely limit our understanding of their dynamics. Holland Lake, a small and deep mesotrophic lake (0.14 km2 surface area and 18.8 m maximum depth) has been considered for stocking with brown trout because it provides extensive cold-water during the summer. Unfortunately, an anoxic layer of about 1.5 to 3 m thickness develops in the upper metalimnion resulting in a negative heterograde dissolved oxygen profile, and eliminating any trout habitat during July and August. The findings of a field study suggest that the occurrence of the metalimnetic oxygen minimum is related to the presence of substantial macrophyte beds in the shallow bays, the particular morphometry of the lake (69% littoral zone), and a significant groundwater inflow and outflow. Density current intrusions that transport oxygen depleted water of high detritus content from the bottom of the shallow bays into the metalimnion of the deep basin in early summer are consistent with exceptionally high observed oxygen depletion rates. It is this horizontal convective transport of materials within the lake in addition to phytoplankton settling from the photic zone above, that strongly affects the dissolved oxygen deficiency in the upper metalimnion of the deep main basin. To create a brown trout habitat, metalimnetic aeration will be required. |
| Paleolimnological Study of Willard and Russell Ponds in New Hampshire | Sushil S. Dixit; Jody N. Connor; Stephen C. Landry | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 3 | 2001 | 197 - 216 | Paleolimnological Study of Willard and Russell Ponds in New Hampshire | Long-term environmental trends in Willard and Russell ponds in New Hampshire were assessed using paleolimnological techniques. Algal microfossils (diatom valves and chrysophyte scales) and pollen remains were analyzed from sediment cores representing the depositional environment of the last 200-300 years. Sediment characteristics and geochemical data were also studied to assess past limnological and watershed changes. The export of ions from the watershed has increased in both ponds and trace metal concentrations in sediments have increased over the post-industrial period. Pollen data suggest that the terrestrial vegetation in the watershed had changed in the past. Stratigraphic changes in diatom and chrysophyte taxa indicated lakewater quality changes in Willard and Russell ponds in the past. Diatom assemblages were quantified to infer past total phosphorus (TP), pH, and chloride (CI) concentrations, using diatom-based inference models that have been developed for the lakes in the northeastern USA. Past inferred TP concentrations remained relatively unchanged and both water bodies can be categorized as oligotrophic for the past 200-300 years. However, inferred pH and CI levels have changed in the study ponds. Although changes in inferred CI are most likely related to watershed disturbances, the recent decline in inferred pH is most likely due to increased acidic precipitation. The study shows the usefulness of a paleolimnological approach in determining long-term water quality monitoring trends. These long-term data would be useful in developing effective lake management and restoration plans in New Hampshire. |
| Long-Term Changes in the Sediment Chemistry of a Large Shallow Subtropical Lake | M. M. Fisher; K. R. Reddy; R. Thomas James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 3 | 2001 | 217 - 232 | Long-Term Changes in the Sediment Chemistry of a Large Shallow Subtropical Lake | Nitrogen (N) and phosphorus (P) content and selected physico-chemical properties of Lake Okeechobee sediments were measured in 1988 and 1998. Based on these measurements, sediments were classified as mud, littoral, peat, sand or rock. Although some minor redistribution has occurred over the previous decade, mud sediments of Lake Okeechobee essentially occupy the same total area. Total surface sediment N and P showed little overall change in the ten-year period. However, lake-wide spatial patterns indicate some localized decreases of total P content in the littoral and northern regions of the lake. Porewater dissolved reactive P showed significant increases at most sites, suggesting that the surface sediments are losing their ability to absorb soluble P. Nutrient management practices in the drainage basin did not lead to decreased levels of N and P in the sediments of the lake. |
| Water Quality Indicators for Reservoirs: A Conceptual Framework | Robert H. Kennedy; Kent W. Thornton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 3 | 2001 | 188 - 196 | Water Quality Indicators for Reservoirs: A Conceptual Framework | Protection and successful stewardship of water resources will require the development and application of management approaches linking societal expectations, designated resource uses and observed resource conditions to management performance. Described here is a conceptual framework that includes indicators of condition and trends, diagnostic and management indicators, and measures of management performance as they relate the management of water resource development projects. When properly applied, these indicators provide valuable insight to complex environmental problems and can be used to effectively support the management and decision-making process. |
| Managing Drinking Water Supplies | G. Dennis Cooke; Robert H. Kennedy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 3 | 2001 | 157 - 174 | Managing Drinking Water Supplies | Efforts to provide safe drinking water cannot begin at the treatment plant. Processes occurring in the watershed can adversely influence drinking water reservoirs, and understanding linkages between these processes and reservoir water quality provides the basis for protecting or improving source water quality. Since the presence of molecules responsible for taste, odor and algal toxin problems, and for the formation of disinfection by-products (DBP) is often related to reservoir trophic conditions, sound and cost-effective water treatment approaches must include considerations for reservoir management. Source water management efforts should include both watershed management, as a means to reduce the loading of materials to the reservoirs, and in-reservoir treatments that ameliorate or minimize the symptoms of eutrophication. Discussed here are considerations for maintaining safe drinking water, water quality assessment approaches, and common methods for managing reservoir water quality. |
| Considerations for Establishing Nutrient Criteria for Reservoirs | Robert H. Kennedy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 3 | 2001 | 175 - 187 | Considerations for Establishing Nutrient Criteria for Reservoirs | The recent requirement to establish nutrient criteria for lakes and reservoirs provides the means for water resource management agencies to link watershed influences and water quality responses. Establishing reference conditions, as required for setting realistic criteria, raises a number of questions concerning the potential importance of differences and similarities between lakes and reservoirs. Discussed here are considerations for establishing reservoir nutrient criteria, including linkages between reservoir design, operation and water quality, spatial heterogeneity in water quality conditions, and analytical approaches. |
| Determinants of Farmer Behavior: Adoption of and Compliance with Best Management Practices for Nonpoint Source Pollution in the Skaneateles Lake Watershed | Eric W. Welch; Frederick J. Marc-Aurele Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 3 | 2001 | 233 - 245 | Determinants of Farmer Behavior: Adoption of and Compliance with Best Management Practices for Nonpoint Source Pollution in the Skaneateles Lake Watershed | Policy makers and public managers have recently implemented a wide range of watershed management programs designed to reduce nonpoint pollution from agriculture. This paper focuses on the progress of one such program. Skaneateles Lake, New York is the drinking water supply of Syracuse City. Granted “filtration avoidance†under the Surface Water Treatment Rules - allowance of unfiltered water supply conditional upon heightened source protection activities - the City, in cooperation with other agencies, established the Skaneateles Lake Watershed Agricultural Program (SLWAP) in 1994 as one element of a broader watershed protection plan. The SLWAP is a 5-10 member interagency pollution prevention program designed to work cooperatively and independently with watershed farmers to develop Whole Farm Plans that incorporate pollution minimizing best management practices. The program is voluntary and not all farmers have agreed to opt in. Using a modified behavioral model, this paper examines adoption and compliance behavior of farmers in the Skaneateles Lake Watershed in New York State. Findings indicate two stages of adoption. Early adopters have lower incomes, indicate that farming is their primary source of income, perceive fairer and more equitable treatment by regulators, believe the Best Management Practices (BMP) will have the desired effect, and are more fearful of regulatory consequences if the Whole Farm Planning effort fails. We call this first stage “regulatory push.†Late adopters are more environmentalist and more influenced by other farmers and the community. We call this second stage “community pull.†In addition, findings regarding compliance indicate that farmers and the management team diverge in their assessments of progress toward implementation of Best Management Practices, indicating some potentially significant communication problems. Concluded recommendations for management of voluntary programs for farmers include: (1) initial implementation efforts should seek out those community leaders are more likely to be cooperative, (2) regulatory threat may be useful during the initial implementation period, and (3) evaluation criteria must be developed cooperatively with and clearly communicated to farmers. |
| Citizen Monitoring of Aquatic Bird Populations Using a Florida Lake | Mark V. Hoyer; John Winn; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 2 | 2001 | 82 - 89 | Citizen Monitoring of Aquatic Bird Populations Using a Florida Lake | Five years of monthly bird counts on a 2.32 km2 lake in north central Florida were used to examine the ability of a citizen volunteer to monitor aquatic bird populations. When compared to published aquatic bird data, collected by professional biologists, the citizen volunteer was able to accurately assess bird abundance and species richness. The monthly counts over a five-year period were also used to examine seasonal patterns in aquatic bird use. We highly recommend the development of citizen based aquatic bird monitoring programs for the assessment of reportedly declining aquatic bird populations. This would be especially useful if entire states programs could be developed to monitor regional as well as temporal trends in aquatic bird populations. |
| Design Parameters for Artificial Aeration of Ice-Covered Lakes | S. A. McCord; S. G. Schladow | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 2 | 2001 | 121 - 126 | Design Parameters for Artificial Aeration of Ice-Covered Lakes | Numerous lakes in cold climates require artificial aeration to maintain fish habitats during ice-cover periods. Mechanical surface aerators (“splashersâ€) are one type of aeration system popular in midwestern parts of the U.S. and Canada. A method is presented to represent the most important physical characteristics of splasher systems designed for small lakes through two dimensionless parameters. Data from several lakes in Wisconsin and Alberta, Canada, where splashers have been operated were used to determine a preliminary, constrained range of values for these two design parameters. |
| Effects of Shoreline Urbanization on Littoral Fish Assemblages | Perry F. Trial; Frances P. Gelwick; Mark A. Webb | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 2 | 2001 | 127 - 138 | Effects of Shoreline Urbanization on Littoral Fish Assemblages | We evaluated modifications associated with shoreline urbanization with regard to effects on littoral habitat use by fishes in Lake Conroe, TX. Among four habitat types present, two had nonurbanized shorelines and were either vegetated or nonvegetated, and two had urbanized nonvegetated shorelines modified with either riprap or retaining walls. In each habitat type, four sites were randomly chosen for repeated sampling (once in each of fall, winter, spring, and summer) using depletion electrofishing inside a block-netted area. Nonvegetated and walled habitats had fewest species and weakest seasonal dynamics. Beginning in fall, vegetated habitat was characterized by various small-bodied taxa, primarily water-column and surface-feeding invertivores and piscivores, but as vegetation died back through the winter, it contained fewer characteristic species. Then in spring and summer, number of characteristic species in vegetation increased to include small-bodied benthic species, and large-bodied piscivores. The species association in walled habitat changed least across seasons, and was characterized by yellow bass (Morone mississippiensis). Associations in nonvegetated and walled habitats had fewer characteristic species than did other habitats, but these increased overall diversity of littoral assemblages in the reservoir. Cumulative effects of increasing urbanization accompanied by conversion of vegetated shoreline to walled habitat would lead to impoverished littoral assemblages. Riprap might be an acceptable alternative to retention walls for stabilizingshorelines. However, addition or protection of native aquatic vegetation also should be considered, especially with regard to mitigation of effects on fishes that are seasonally or uniquely associated with that habitat type, and whose populations had declined following past efforts to control vegetation. |
| Hepatic Copper Concentrations and Condition Factors of Largemouth Bass (Micropterus salmoides) and Common Carp (Cyprinus carpio) from Copper Sulfate-Treated and Untreated Reservoirs | Michael A. Anderson; Michael S. Giusti; William D. Taylor | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 2 | 2001 | 97 - 104 | Hepatic Copper Concentrations and Condition Factors of Largemouth Bass (Micropterus salmoides) and Common Carp (Cyprinus carpio) from Copper Sulfate-Treated and Untreated Reservoirs | The application of copper sulfate to surface waters for nuisance algae control has been practiced for decades. Despite its long history of use, questions persist about the fate and bioavailability of copper (Cu) in water bodies receiving copper sulfate applications. This study compares the hepatic Cu content of largemouth bass (Micropterus salmoides) and common carp (Cyprinus carpio) sampled from two reservoirs in southern California with contrasting copper sulfate treatment histories. Lake Mathews is the terminal reservoir for the Colorado River Aqueduct and has received over 2000 tons of CuSO4·5H2O over the past ~20 years. As a result of repeated copper sulfate treatment, Lake Mathews has an average Cu sediment content of 290 μg·g-1 dry weight. Copper Basin Reservoir, also part of the Colorado River Aqueduct system, has not previously received any CuSO4 applications and thus has a much lower sediment Cu content (8 μg·g-1). The mean hepatic Cu content of small bass (mean length ~24 cm) was significantly higher for individuals sampled from Lake Mathews than from Copper Basin Reservoir (22.9±20.5 vs. 4.3±4.4 μg·g-1, respectively), although no statistically significant difference (at p≤0.05) was found for large bass (mean length ~41 cm) from the two reservoirs. The mean hepatic Cu concentration of carp from Lake Mathews was significantly higher (at p≤0.05) than that of carp from Copper Basin Reservoir (76.8±42.3 vs. 51.3±22.4 μg·g-1, respectively). No apparent negative effects associated with copper sulfate application or copper accumulation within fish were found, however, as condition factors (K) for fish from Lake Mathews were either comparable to or higher than those from Copper Basin Reservoir (e.g., for small bass, K was 1.78±0.11 vs. 1.46±0.10, respectively). |
| A Protocol for Standardizing Secchi Disk Measurements, Including Use of a Viewer Box | David G. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 2 | 2001 | 90 - 96 | A Protocol for Standardizing Secchi Disk Measurements, Including Use of a Viewer Box | Despite being used by limnologists and oceanographers for over a century, the use of the Secchi disk for estimating water transparency has no standardized protocol. Because of this lack of uniformity, and the inherent optical problems with most current Secchi depth procedures, an appeal is made for production of a standardized protocol for Secchi observations. A possible protocol, including the use of a closed-ended viewer box on the sunny side of the boat, is suggested here. To assist in protocol development, this paper briefly reviews some aspects of optical physics and examines some recent field measurements made by staff of New York City Department of Environmental Protection. These measurements were made using a closed-ended viewer box and are compared with simultaneous naked-eye measurements. The use of a viewer box increases Secchi depth measurement by removing the interfering effects of water surface glare and glitter. A viewer box also increases between-observer precision. Measurements made both with and without the viewer box are slightly greater on the shady side of the boat than on the sunny side; the latter is the preferred side if Secchi data are to be related to other optical properties. The difference between viewer box and naked eye measurements increases with increasing wave height but not with increasing illuminance. |
| Natural and Management-Induced Reduction in Monimolimnetic Volume and Stability in a Coastal, Meromictic Lake | Stuart D. Ludlam; Brian Duval | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 2 | 2001 | 71 - 81 | Natural and Management-Induced Reduction in Monimolimnetic Volume and Stability in a Coastal, Meromictic Lake | Lower Mystic Lake is a coastal meromictic lake with a northern and southern basin. Although the southern basin has remained meromictic, the northern, shallower basin became holomictic in the early 1980s. A secondary chemocline forms above the primary chemocline, so that mixing during autumnal overturn does not always reach to the depth of the primary chemocline. The secondary chemocline may develop and intensify during periods when wind action and seiche activity are not expected, and may persist as a distinct feature for over a year. The source of the solutes in the secondary chemocline appears to be the primary chemocline and the monimolimnion. The Amelia Earhart Dam, constructed in 1966, prevents any further influx of seawater that was necessary to maintain the meromictic stratification. As a result, depth of the primary chemocline has increased at an irregular rate since the last influx of seawater. Between 1966-1994 the chemocline was eroded downwards 12 m, causing a 95% reduction in monimolimnetic volume. Of the total loss of volume between 1968 and 1994, approximately 4% was caused by management pumping water from the monimolimnion, that is, about 29% of the volume of the chemocline and monimolimnion as they existed in 1977, just prior to the major effort in treatment. The remainder of the monimolimnion was removed by wind action, convective circulation and other natural means. Meromictic stability showed a linear decrease between 1974 and 1994. During that time period, average annual loss of meromictic stability due to natural processes amounted to approximately 64 g-cm cm-2 yr-1 for the south basin alone, and 84 gm-cm cm-2 yr-1 for the lake as a whole. Using stability measurements it was projected that the monimolimnion would most probably mix completely into the lake by approximately 2013-2014. Overall, completion of the Amelia Earhart Dam had a greater effect on the loss of the monimolimnion than efforts to remove this stratum by pumping as it prevented replacement of water eroded from the chemocline with fresh seawater. |
| Correlations of Sedimentary Diatoms with Watershed Land Use and Limnological Conditions in Northern New Jersey Lakes | B. H. Hill; J. P. Kurtenbach | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 2 | 2001 | 105 - 120 | Correlations of Sedimentary Diatoms with Watershed Land Use and Limnological Conditions in Northern New Jersey Lakes | Sedimentary diatoms were collected from 62 New Jersey lakes and correlated with limnological and land use variables. Four diatom attributes (species richness, percentage dominance by a single diatom species, percentage acidobiontic species, percentage eutraphentic species) and 4 diatom indices, Centrales:Pennales (C/P), Araphidinaea:Centrales (A/C), Generic Diatom (GI), and diatom index of biotic integrity (DIBI), were compared to the environmental variables. Lakes were classified as forested lakes (±80% the watershed in forests), mixed land use lakes (21-79% forests), or deforested lakes (≤20% forests) based on the satellite imagery. Forested lakes had significantly lower specific conductance and pH, greater ZSD and hypo limnetic DO, and less urban land use within their watersheds than either mixed land use or deforested lakes. Forested lakes also had greater species richness, lesser dominance by single species, more acidobiontic diatoms, fewer eutraphentic diatoms, lower C/P, and higher DIBI scores. There were no significant differences among lake classes for A/C or GI indices. The 4 diatom attributes and 4 diatom indices were correlated with each other, though A/C was not significantly correlated with any of the diatom attributes or indices. The remaining 3 diatom indices were highly correlated with taxa richness, percentage dominance, and percentage acidobiontic species. The attributes and indices were variously correlated with the 13 limnological and watershed land use variables, with alkalinity, specific conductance, pH, ZSD, and percentage of the watershed in forests and urban land uses exhibiting the strongest correlations. Canonical correlation analysis revealed significant correlations between the diatom attributes and indices and the environmental axis related to lower alkalinity and pH, and higher ZSD and percentage of the watershed in forests. Our results suggest that diatom attributes and indices are useful indicators of the ecological condition of lakes and that these attributes and indices respond to human disturbances within a lake's watershed. Of the indices tested, the DIBI appears to be the most useful, significantly correlating with stressors and limnological variables of interest, especially the loss of forests from watersheds. The results support the use of sedimentary diatom attributes and indices for monitoringlake water-quality and watershed land use changes relative the management of these resources. |
| Comparison of Submerged Aerator Effectiveness | Connie D. DeMoyer; John S. Gulliver; Steven C. Wilhelms | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 2 | 2001 | 139 - 152 | Comparison of Submerged Aerator Effectiveness | The effectiveness of three different submerged aerators (diffusers), a membrane diffuser, a coarse bubble diffuser, and a soaker hose, is compared by analyzing their performance parameters at varying gas flow rates and water depths of up to 10 meters. The type of diffuser chosen for a specific application depends on aeration characteristics such as the total mass transfer coefficient, standard oxygen transfer rate (SOTR), standard oxygen transfer efficiency (SOTE), and standard aeration efficiency (SAE). From experimental data, the effects of the gas flow rate and submerged depth on the total mass transfer coefficient and SOTR are determined up to a 10 meter depth. As the flow rate and diffuser depth are increased, the mass transfer coefficient and the SOTR increase for all three diffusers. At low gas flow rates, the segment of soaker hose transfers oxygen at the highest rate. The coarse bubble diffuser transfers oxygen at a lesser rate than the soaker hose but is capable of performing at higher gas flow rates. The membrane diffuser performance resembles the high transfer of a soaker hose before approaching the transfer behavior of the coarse bubble diffuser at higher flow rates. Relationships are also defined for the SOTE and SAE. Non-dimensional parameter correlations quantify the dependence of the performance parameters on the gas flow rate and depth and provide a means of predicting diffuser behavior for specified system applications. |
| Impacts of Water Column Turbidity on the Survival and Growth of Vallisneria americana Winterbuds and Seedlings | Robert D. Doyle; R. Michael Smart | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 1 | 2001 | 17 - 28 | Impacts of Water Column Turbidity on the Survival and Growth of Vallisneria americana Winterbuds and Seedlings | Survival and growth of Vallisneria americana winterbuds was significantly related to both initial winterbud size and to the water column turbidity under which the plants were grown. Larger winter buds showed better survival and better growth than did smaller ones. Turbidity likewise significantly impacted the survival and growth of the plants. Over the turbidity range of 0.2-45 NTU (53-7% total incident light), the plants were shown to have progressively poorer survival and to produce fewer rosettes and total number of leaves. Vallisneria americana seedlings were likewise influenced by turbidity. Under high turbidity conditions the seedlings had significantly higher mortality, while surviving plants produced fewer rosettes and accumulated less biomass than seedlings grown under low turbidity conditions. In addition, under turbid conditions the seedlings had to invest proportionally more energy into above-ground tissues. |
| Impacts of Water Column Turbidity on the Survival and Growth of Vallisneria americana Winterbuds and Seedlings | Robert D. Doyle; R. Michael Smart | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 1 | 2001 | 17 - 28 | Impacts of Water Column Turbidity on the Survival and Growth of Vallisneria americana Winterbuds and Seedlings | Survival and growth of Vallisneria americana winterbuds was significantly related to both initial winterbud size and to the water column turbidity under which the plants were grown. Larger winterbuds showed better survival and better growth than did smaller ones. Turbidity likewise significantly impacted the survival and growth of the plants. Over the turbidity range of 0.2-45 NTU (53-7% total incident light), the plants were shown to have progressively poorer survival and to produce fewer rosettes and total number of leaves. Vallisneria americana seedlings were likewise influenced by turbidity. Under high turbidity conditions the seedlings had significantly higher mortality, while surviving plants produced fewer rosettes and accumulated less biomass than seedlings grown under low turbidity conditions. In addition, under turbid conditions the seedlings had to invest proportionally more energy into above-ground tissues. |
| Book Review | John J. Ney | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 1 | 2001 | 66 | Book Review | |
| Influence of Factors Associated with Water Level Drawdown on Phosphorus Release from Sediments | R. Lawrence Klotz; Susan A. Linn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 1 | 2001 | 48 - 54 | Influence of Factors Associated with Water Level Drawdown on Phosphorus Release from Sediments | Studies on lake sediments showed that drying and freezing, as would occur during the management practice of water level drawdown, increased the release of phosphorus from the sediments over controls. P release from sediments increased as a result of drying in all ten lake sites studied, but the amount of P released varied significantly between sites. Phosphorus release ranged from 0.9 to 38.2 μg·g-1 dry weight sediment and the increase over wet controls ranged from 3 to 84 fold. The effect occurred within 4 days of drying in the laboratory. Drying of the epilithon on cobbles resulted in higher P release. Freezing of sediments also resulted in increased nutrient release, with 70 times more P released from frozen sediments compared to unfrozen controls. The full effect of freezing was realized within 3 days. The combined effect of drying then freezing did not increase the amount of P released above that of sediments that were frozen without prior drying. P release as a result of drying was significantly correlated with sediment P and organic content. The data indicate that the P released resulted from the death of microorganisms due to drying and freezing. The results show that lake drawdown may significantly increase internal P loading to lakes of central New York State. |
| On Determining the Principal Source of Phosphorus Causing Summer Algal Blooms in Western Washington Lakes | Eugene B. Welch; Jean M. Jacoby | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 1 | 2001 | 55 - 65 | On Determining the Principal Source of Phosphorus Causing Summer Algal Blooms in Western Washington Lakes | Internal loading of total phosphorus (TP) calculated from mass balance averaged 68±21% of the total (internal + external) summer loading in 14 of 17 western Washington lakes that had internal loading. Moreover, whole-lake mean TP for the 16 lakes with complete mass balance data was 50 ±9 μg·L-1, which was similar to TP (51±18 μg·L-1) predicted from summer internal P loading determined by the maximum change in lake TP. Lake TP predicted from summer external loading, assuming a nominal retention coefficient, was only 30±9 μg·L-1. In-lake management measures to control internal loading had been either implemented or recommended in 14 of the 17 lakes. Summer P was substantially reduced in 10 of 12 lakes (or separate lake basins) receiving in-lake treatments, substantiating the dominant effect of internal loading. These observations indicate that emphasis on reducing external loads only, through watershed best-management practices (BMPs), without in-lake measures, would not have been the most cost-effective approach to control summer algal blooms in these lakes, especially if external loads were nonpoint and of minor importance during summer when algal problems are most prevalent. Comparison of external and internal P loads during summer, as illustrated here, is recommended so that in-lake controls are considered with watershed controls in a balanced approach to cost-effective lake management. |
| Integrating Nature Conservation with Hydro-Electric Development: Conflict Resolution with Lakes Manapouri and Te Anau, Fiordland National Park, New Zealand | Alan F. Mark; Keith S. Turner; Carol J. West | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 1 | 2001 | 1-25 | Integrating Nature Conservation with Hydro-Electric Development: Conflict Resolution with Lakes Manapouri and Te Anau, Fiordland National Park, New Zealand | Thirteen years of public debate and protest followed the New Zealand Government's 1960 formal agreement with a multinational consortium to raise Lakes Manapouri (142 km2) and Te Anau (352 km2), in Fiordland National Park, to maximise hydro-electric generation for an aluminum smelter proposed by Comalco Ltd. This controversy was a major factor in the 1972 change of government which rejected lake raising and also appointed Guardians, from among the campaign leaders, to advise on lake management. Lake management guidelines were devised from geomorphological and ecological studies correlated with a 37-year lake level record. High, Main and Low Operating Ranges were recognised within the natural variation (Te Anau 3.5 m; Manapouri 4.8 m). High Operating Range defines both maximum duration at a particular level and minimum periods of subsequent lowering to satisfy ecological requirements of shoreline forest. Low Operating Range defines both draw-down rates (to prevent slumping of fine beach sediments) and maximum annual duration at particular levels (to prevent combing down and possible loss over narrow shelves, of beach sediments). Main Operating Ranges have negligible restrictions. The guidelines were verified in practice and incorporated in legislation in 1981. Monitoring of shoreline vegetation and beaches has confirmed achievement of objectives. Wide consultation, aimed at further conflict resolution and replacement of empowering legislation by consents under the 1991 Resource Management Act, was completed, with guidelines and monitoring incorporated, in 1996. We believe the scientifically based management guidelines have effectively integrated nature conservation with hydro-electric development in Fiordland National park, a World Heritage Area since 1986. This approach should be applicable to natural lakes elsewhere. |
| Effects of Fisheries Management and Lakeshore Development on Water Quality in Diamond Lake, Oregon | J. M. Eilers; C. P. Gubala; P. R. Sweets; D. Hanson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 17 | 1 | 2001 | 29 - 47 | Effects of Fisheries Management and Lakeshore Development on Water Quality in Diamond Lake, Oregon | Paleolimnological techniques were used to assess water quality changes in a heavily used recreation lake in the Oregon Cascades. Diamond Lake was fishless prior to 1910, but has been intentionally stocked with rainbow trout annually and unintentionally stocked with tui chub in the 1930s and the 1990s. The lake was converted from a mesotrophic system to an eutrophic lake as a consequence of watershed inputs of nutrients associated with shoreline development and biomanipulation in the form of fisheries management. Despite installation of a sewage collection and diversion system, Diamond Lake has increased in sediment accumulation rate and the diatom community has shown an increase in Fragilaria crotonensis and Asterionella formosa, species which are often associated with eutrophication. The two largest increases in sediment accumulation rate and alterations in the diatom community correspond most closely with the two increases in the tui chub population rather than shoreline development. Diatom-inferred (DI) pH increased from 7.95 circa 1910 to over 8.20 in the 1940s. The effects of a rotenone treatment in 1954 to eliminate the tui chub are evident in the short-term decrease in DI- pH and the response of the diatom community. The lake also experienced a major increase in zooplankton abundance in the 20th century as indicated by the remains in the sediment. The results illustrate the need to consider both external and internal sources of nutrients in lake restoration and management attempts. |
| Recent Eutrophication Histories in Lac Ste. Anne and Lake Isle, Alberta, Canada, Inferred Using Paleolimnological Methods | Jules M. Blais; Katharine E. Duff; David W. Schindler; John P. Smol; Peter R. Leavitt; Michael Agbeti | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 4 | 2000 | 292 - 304 | Recent Eutrophication Histories in Lac Ste. Anne and Lake Isle, Alberta, Canada, Inferred Using Paleolimnological Methods | A paleolimnological analysis of Lac Ste. Anne and Lake Isle, two eutrophic lakes in central Alberta, Canada, confirmed that they were naturally eutrophic, but have become increasingly eutrophic after the 1960s as 27% and 24% of their watersheds, respectively, were developed for urban and agricultural purposes. This was shown by a predominance of Chironomidae head capsules indicating periodic anoxia in bottom waters, high abundances of eutrophic diatoms (e.g., Aulacoseira granulata, Fragilaria crotonensis, Stephanodiscus niagarae and S. parvus), and, in Lac Ste. Anne, an enrichment of pigments from filamentous cyanobacteria (e.g., myxoxanthophyll) in post-1960 sediments. Evidence of periodic anoxia in the profundal zone was also provided by a scarcity of reducible phosphorus in the sediments. Lac Ste. Anne showed the largest changes during the 1960s and 1970s, when increases were observed in the abundance of hyper-eutrophic diatoms (e.g., S. parvus) as well as sedimentary phosphorus fractions and algal pigments. The changes in Lake Isle were similar, but more subtle. Results indicate that reduced anthropogenic activities would still result in eutrophic systems, but some improvements in water quality would be achieved, particularly in Lac Ste. Anne. |
| Water Quality Changes from Human Activities in Three Northeastern USA Lakes | Sushil S. Dixit; Aruna S. Dixit; John P. Smol; Robert M. Hughes; Steven G. Paulsen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 4 | 2000 | 305 - 321 | Water Quality Changes from Human Activities in Three Northeastern USA Lakes | Diatom and chrysophyte assemblages from sediment cores were analyzed to assess the long-term trends of lake water quality in French Pond (New Hampshire), Joes Pond (Vermont), and Kenoza Lake (Massachusetts) as part of the US EPA's EMAP-SW (Environmental Monitoring and Assessment Program-Surface Waters) program in the northeastern USA. Sediment characteristics and geochemical data were also examined to interpret past limnological and watershed changes. Geochemical data indicate that exports of ions from the watersheds have increased and the lakes have received higher trace metal inputs over the post-industrial period. Stratigraphic changes in common diatom and chrysophyte taxa indicate that, over the last century, distinct water quality changes have occurred. Using the diatom- and chrysophyte-based weighted averaging inference models developed for lakes in the northeast, past changes in assemblages were used to infer trends in lakewater total phosphorus (TP), pH, and CI. In French Pond, inferred TP, pH, and CI changes were small, whereas Joes Pond and Kenoza Lake have experienced major changes. The latter two lakes have become more eutrophic, and lakewater pH and CI have also increased from their background values. Inferred water quality changes are closely related to watershed disturbances and resulting eutrophication. Our study illustrates that the inference models developed in EMAP-SW can be successfully applied in establishing long-term water quality trends in lakes throughout the northeastern USA. These models and subsequent sediment core data will help lake managers to develop effective management plans and to establish suitable targets for the restoration of other lakes of concern. |
| The Potential For Wave Disturbance in Shallow Florida Lakes | Roger W. Bachmann; Mark V. Hoyer; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 4 | 2000 | 281 - 291 | The Potential For Wave Disturbance in Shallow Florida Lakes | We applied wave theory to calculate the extent and frequency that we would expect wave-driven surface water movements to disturb the sediments in 36 Florida lakes covering a broad range of surface areas and mean depths. The calculated per cent of the lakebed subject to wave disturbance at one time or another ranged from 6 to 100% and the per cent of the time 50% of the lakebed was disturbed ranged from 0 to 65%. The large Florida lakes, Apopka, Okeechobee, and Istokpoga showed high levels of calculated wave disturbance, which was consistent with the conclusions of previous investigations. Historic water level fluctuations in Lake Apopka were calculated to have major effects on wave disturbance in that lake. The dynamic ratio (the square root of lake surface area in square kilometers divided by the mean depth in meters) was significantly related to various measures of wave disturbance in our sample lakes. For lakes with ratio values above about 0.8 the entire lakebed was subject to wave disturbance at least some of the time. The dynamic ratio was also related to lake water quality. We found that increases in the dynamic ratio were significantly related to decreases in water quality as measured by total phosphorus, total nitrogen, chlorophyll, and Secchi disk depth. Calculations of wind disturbance by waves need to be modified in lakes with extensive beds of macrophytes, where water levels change and in periods where climatic fluctuations result in changes in wind regimes. |
| A Limnological Survey of Third Sister Lake, Michigan with Historical Comparisons | T. B. Bridgeman; C. D. Wallace; G. S. Carter; R. Carvajal; L. C. Schiesari; S. Aslam; E. Cloyd; D. Elder; A. Field; K. L. Schulz; P. M. Yurista; G. W. Kling | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 4 | 2000 | 253 - 267 | A Limnological Survey of Third Sister Lake, Michigan with Historical Comparisons | Third Sister Lake in southeastern Michigan has been a focus of ecological studies since 1904. In 1999, we surveyed several physical, chemical, and biological parameters of the lake and compiled data collected by University of Michigan students since 1975. Comparison of dissolved oxygen profiles from years 1927-29, 1939-42 to recent data (1992-99) indicate a decrease in maximum oxygenation of bottom waters at fall turnover (8 mg O2·L-1 maximum 1927-29, 1939-42 vs. 4 mg O2·L-1 1980, 1992-93) and more rapid depletion of oxygen in the hypolimnion following stratification. In early studies, oxygen persisted (> 3 mg L-1) at all depths from mid-November to May (1927-29, 1939-42). There has been no evidence of spring mixing in recent years and bottom waters have become anoxic by late January. The diversity and density of offshore benthic organisms has declined from at least 12 species and an average density of 167000·m-2 in 1927 to 4-5 species at 15144 · m-2 in 1999. Overall, benthic populations shifted from the deepest portions of the lake (16-18 m benthos) to shallower depths and only Chaoborus was found at bottom contours > 10 m in 1999. Mean chloride concentration [Cl·] increased nearly 13-fold from 19 mg L-1 to 241 mg L-1 between 1981 and 1988, with 260 mg L-1 recorded in 1999. Calculations of whole-lake stability incorporating increases in [Cl·] indicate that about 60% more energy would be required to mix the lake following ice-out in 1999 compared to 1981. During the winter-spring transition, net respiration dominated under ice (4.1 g C·m-2 d-1) and immediately afterice-out(0.32 g C·m-2 d-1)in 1999. The phytoplankton community was dominated by cyanobacteria (Oscillatoria) from February to April. Under ice cover, bacterial abundance increased with depth from an average of 4.17 105 cells ml-1 (1-5 m) to 18.9 105 cells ml-1 (15 m). |
| Non-Algal Seston, Light, Nutrients and Chlorophyll in Missouri Reservoirs | Matthew F. Knowlton; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 4 | 2000 | 322 - 332 | Non-Algal Seston, Light, Nutrients and Chlorophyll in Missouri Reservoirs | Limnological measurements were performed at five or six Missouri reservoirs in June-September 1992-1995 to examine the relation of light conditions and non-algal seston (NAS) to chlorophyll (CHL) and dissolved nutrient concentrations. NAS was estimated as the sum of non-volatile suspended solids and filterable (Whatman 934AH filter) suspended solids. Mean mixed layer irradiance (Imix) varied ≈20 fold among observations, largely due to variation in light attenuation by NAS. In 42% of the observations, Imix was less than 7 E·m-2 d-1, a range where light limitation is likely. NAS comprised 15-96% (mean= 58%) of total seston and accounted for 89% of the temporal and inter-site variation in Imix. NAS was strongly correlated to total phosphorus (TP) and soluble reactive phosphorus (SRP) concentrations (r= 0.91 and r=0.84, respectively, p<0.0001). When NAS > 5 mg·L-1 or Imix was < 5 E m-2 d-1, SRP and dissolved inorganic N (DIN) were usually at concentrations capable of saturating algal nutrient uptake (SRP >3 μg·L-1, DIN >50 μg·L-1), suggesting light limitation replaced nutrient limitation under those conditions. Light limitation resulting from NAS in turbid lakes may alter the relationship of phytoplankton to phosphorus, yielding a CHL-TP relationship that is dome-shaped rather than asymptotic. Variation in the relation of NAS to TP will affect how CHL responds to nutrients in individual waterbodies. |
| Chlorophyll Maxima in Mountain Ponds and Lakes, Mount Rainier National Park, Washington State, USA | Gary L. Larson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 4 | 2000 | 333 - 339 | Chlorophyll Maxima in Mountain Ponds and Lakes, Mount Rainier National Park, Washington State, USA | Hypolimnetic chlorophyll maxima are common in clear lakes and often occur at depths with between 1 and 0.1% of the surface incident light. Little is known, however, about the concentrations of chlorophyll in thermally unstratified mountain ponds and how these concentrations compare to epilimnetic and hypolimnetic concentrations in mountain lakes. The objectives of this study were to document the concentrations of chlorophyll in thermally unstratified ponds and stratified lakes in Mount Rainier National Park (MORA) and to compare the results with concentrations and distributions of chlorophyll in clear-deep lakes in the Oregon Cascade Range and the Sierra Nevada Range. Thirty-two ponds (<2.5 m deep) and 14 lakes(>9.9 m deep) were sampled primarily during the summers of 1992 to 1996 at MORA. Water samples from near the surface (0.1-0.5 m) of ponds and near the surface and near the bottom of lakes were collected over the deepest part of each system. One exception, Mowich Lake, was sampled at seven depths between the surface and 50 m (Z=58.6 m). Chlorophyll concentrations were low in all systems, but higher in ponds (average 1.8 μg·L-1) than in lakes. Chlorophyll concentrations were higher in hypolimnetic lake samples (average 0.7 μg·L-1) than in epilimnetic lake samples (average 0.2 μg·L-1). Elevated concentrations of chlorophyll in mountain ponds, relative to those in hypolimnetic lake samples, may have been influenced by increased nutrient availability from interactions at the mud-water interface and, in this park, defecation by elk that used many of the ponds as wallows. Mowich Lake showed a chlorophyll maximum (~1.5 μg·L-1) near the lake bottom. Based on Secchi disk clarity readings, the depth of 1.0% incident surface solar radiation was greater than the maximum depths of the ponds and lakes. Comparative data from other clear-deep lakes in the Oregon Cascade Range and Sierra Nevada Range suggested that deep-chlorophyll maxima (~1.5 μg·L-1) occurred at <1.0% and > 0.1% of the incident surface solar radiation, and that the typical maximum depths ranged between 75 and 140 m during thermal stratification. |
| Trophic Conditions and Water Chemistry of Lakes on Cape Cod, Massachusetts, USA | Toby D. Ahrens; Peter A. Siver | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 4 | 2000 | 268 - 280 | Trophic Conditions and Water Chemistry of Lakes on Cape Cod, Massachusetts, USA | Sixty lakes and ponds distributed throughout the Cape Cod peninsula were each sampled three times during 1996-1998 in order to determine the chemical conditions of the waterbodies. The study lakes, situated on either glacial moraine, glacial outwash plain or post-glacial sand accumulations, ranged in surface area from 3.6 ha to 301 ha and in maximum depth from 1 m to 26 m. The dominant ionic species in all lakes were Na+ and Cl-, likely due to inputs from sea spray. Conductivity and the relative charge contribution from Na+, Cl- and Mg2+ increased with distance out onto the peninsula, whereas the contribution due to Ca2+ decreased along the same distance gradient. Concentrations of Mg2+ were greater than those of Ca2+ in the study lakes, and the concentrations of the latter cation were very low compared to other areas in the northeast U.S. Except for the eutrophic lakes situated on the post-glacial sand accumulations on the outer tip of Cape Cod, the water bodies were, in general, low in total phosphorus, total nitrogen and chlorophyll-a levels, had high Secchi disk depths, and were best classified as oligotrophic. The pH and alkalinity (except for lakes situated on the post-glacial sand accumulations) declined with distance out onto the peninsula. The mean pH and alkalinity of water bodies located closest to the mainland were 6.8 and 71 μeq·L-1, respectively, but declined to only 5.3 and-7.5 μeq·L-1 on the outer Cape. Findings are compared to other studies in the northeast U.S. |
| Long and Short Term Effects of Waterfowl on Collins Lake, an Urban Lake in Upstate New York | Peter Tobiessen; Elizabeth Wheat | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 4 | 2000 | 340 - 344 | Long and Short Term Effects of Waterfowl on Collins Lake, an Urban Lake in Upstate New York | The effect of bird density on water quality parameters of Collins Lake was examined at three time scales: yearly, seasonally, and weekly. There was no relationship between bird sightings and either coliform bacteria or Secchi disc transparency on a seasonal or long-term (19 year) period. There was also no increase in spring chlorophyll levels over the 19 year period, even though the annual total bird sightings increased almost three times over that period. However, chlorophyll levels did increase during the ice-free season as shown by an almost doubling of fall chlorophyll levels between 1978 and 1997. Increased bird density is considered the most probable cause for these elevated fall chlorophyll levels. The increase in summer resident birds appeared to have a greater effect on chlorophyll levels than migratory birds. There was no observable effect of bird density on chlorophyll levels on a weekly basis, but the large number of other variables changing in the lake during the study period may obscure any trend on this time scale. |
| Preliminary Evaluation of Forced Air-Drying for Preserving Chlorophyll on Glass Fiber Filters | Paul J. Godfrey; Peter A. Kerr | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 3 | 2000 | 222 - 234 | Preliminary Evaluation of Forced Air-Drying for Preserving Chlorophyll on Glass Fiber Filters | An alternative method of preserving filtered chlorophyll samples allows immediate filtration of samples by professional lake managers and volunteer monitors with inexpensive transfer to a laboratory. Using a simple forced air-drying device, samples can be preserved for two weeks and, perhaps, as long as 1-1/2 months without significant change in pigment levels. Filters may be sent by first class mail to a laboratory after wrapping the filters in aluminum foil. A series of 5 experiments was conducted to explore the parameters for maximum extension of the holding time. Results suggest that preserving filters by forced air-drying may be equivalent to other methods such as immediate analysis or freezing, and may be better under many conditions common to field sampling. |
| A Management Alternative for Lake Apopka | Daniel E. Canfield Jr.; Roger W. Bachmann; Mark V. Hoyer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 3 | 2000 | 205 - 221 | A Management Alternative for Lake Apopka | We examine the idea that whenever high levels of planktonic algae impair a lake, nutrient control is the first step to be taken regardless of what other management actions might be contemplated. Our example is Lake Apopka, a 12,500 ha, shallow (1.7 m), polymictic lake in central Florida. Prior to 1947, the lake was dominated by macrophytes, was reputed to have clear waters, and had a national reputation for its largemouth bass fishery. Following a hurricane in 1947, the lake switched to a turbid, algal state and the bass fishery is all but gone. For over 30 years, it was either implied or stated directly that nutrient enrichment from anthropogenic activities, especially farms along the north shore, was to blame for this change and the lack of macrophyte recovery. The current management plan is to remove the farm nutrient supply by purchasing the farms under the theory that this will lower the total phosphorus concentration in the water and thus restore the lake. We have developed the most probable phosphorus budgets for the lake based on the studies of others and have determined that a fluid mud layer that is frequently resuspended by the wind will lead to high internal loading and slow the drop in phosphorus concentration. The equilibrium phosphorus concentration will lie between 52 and 88 mg·m-3, so the lake will remain in its eutrophic state. We propose an alternative management plan using artificial reefs that will focus on restoring the largemouth bass fishery in the immediate future. This idea is attractive because bass fishing was the dominant use of this lake in the past, it can be accomplished without waiting for a change in trophic state, and it can produce results in a relatively short period of time. |
| Book Review | Owen Lind | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 3 | 2000 | 248 | Book Review | |
| Temporal Water Chemistry Trends (1967–1997) for a Sample (127) of Florida Waterbodies | Julia B. Terrell; David L. Watson; Mark V. Hoyer; Michael S. Allen; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 3 | 2000 | 177 - 194 | Temporal Water Chemistry Trends (1967-1997) for a Sample (127) of Florida Waterbodies | Total phosphorus, total nitrogen, total chlorophyll and Secchi visibility data from 127 Florida lakes across three time periods, Early (1967-1972), Middle (1979-1981), and Present (1996-1997) were compared using paired t tests and repeated measures analyses of variances. Although the population of Florida has increased 116% over the last 27 years, expected increases in lake concentrations of nutrients were not found. For this sample of lakes, total phosphorus concentrations decreased over a 30-year time period and total nitrogen concentrations showed no significant change. Secchi visibility, one of the simplest parameters to measure and easily understood by lake-users, also showed no significant change over time. The sample of lakes showed a significant but small increase in total chlorophyll concentrations. The increase was unexpected because total phosphorus concentrations decreased and total nitrogen concentrations stayed the same, suggesting that other factors were impacting total chlorophyll concentrations in this group of lakes. It is speculated that changes in color, fluctuating water levels, and increases in the amount of aquatic plant control over time may help explain some of the increases in total chlorophyll. Independent estimates of normal month-to-month and year-to-year temporal variance for Florida lakes were calculated using long-term Florida LAKEWATCH data (71 lakes, with greater than 4 years of monthly data) and compared to the variance among the Early, Middle, and Present time periods. Most of the differences detected among the time periods using statistical analyses were within calculated normal monthly temporal variance. Thus, increased nutrient concentrations or decreased water clarity, that is often speculated to occur with population growth and watershed development, have not been documented in this sample of Florida lakes. |
| Rehabilitation of Delavan Lake, Wisconsin | Dale M. Robertson; Gerald L. Goddard; Daniel R. Helsel; Kevin L. MacKinnon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 3 | 2000 | 155 - 176 | Rehabilitation of Delavan Lake, Wisconsin | A comprehensive rehabilitation plan was developed and implemented to shift Delavan Lake, Wisconsin, from a hypereutrophic to a mesotrophic condition. The plan was threefold: (1) reduce external phosphorus (P) loading by applying Best Management Practices in the watershed, enhance an existing wetland, and short-circuit the inflows through the lake, (2) reduce internal P loading by treating the sediments with alum and removing carp, and (3) rehabilitate the fishery by removing carp and bigmouth buffalo and adding piscivores (biomanipulation). The first and second parts of the plan met with only limited success. With only minor reductions in internal and external P loading, P concentrations in the lake returned to near pre-treatment concentrations. The intensive biomanipulation and resulting trophic cascade (increased piscivores, decreased planktivores, increased large zooplankton populations, and reduced phytoplankton populations) eliminated most of the original problems in the lake (blue-green algal blooms and limited water clarity). However, now there is extensive macrophyte growth and abundant filamentous algae. Without significantly reducing the sources of the problems (high P loading) in Delavan Lake, the increased water clarity may not last. With an improved understanding of the individual components of this rehabilitation program, better future management plans can be developed for Delavan Lake and other lakes and reservoirs with similar eutrophication problems. |
| Agricultural Best Management Practices and the Decline in Surface Water Total Phosphorus Concentrations in an Impounded Everglades Marsh | Michael J. Maceina | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 3 | 2000 | 235 - 247 | Agricultural Best Management Practices and the Decline in Surface Water Total Phosphorus Concentrations in an Impounded Everglades Marsh | Agricultural Best Management Practices (BMPs) in the 290,000 ha Everglades Agricultural Area (EAA) resulted in a 55% reduction in phosphorus loading to the remnant Florida Everglades in 1996-98, exceeding the 25% load reduction mandated by law. Consonant with this, discharge total phosphorus concentrations (TP) declined from 173 ug·L-1 in the 1980s to 103 ug·L-1 during 1996-98. Although not mandatory until 1995, BMP activity started in the EAA in the mid-1980s. I analyzed 3,798 surface water TP samples collected from 1980 to 1999 in a 54,700 ha impounded Everglades marsh that received surface water inflows from the EAA to examine temporal changes in TP. A gradient of high (> 100 ug·L-1) to low (about 10 ug·L-1) TP existed from northern regions that received EAA discharge south to interior regions of the marsh. During the 1980s, higher TP concentrations extended further south into the marsh, but that process reversed in the 1990s. During the 1990s, wet climatic conditions occurred and TP was inversely correlated to water levels throughout the marsh. However in nearly all regions, TP declined between 1980 and 1999 after accounting for the effects of water levels. Marsh TP was correlated to inflow TP in the regions nearest to the discharge gates, and inflow TP declined from about 150 to 50 ug·L-1 with the implementation of BMPs. In addition, this marsh was kept essentially flooded for 18 years to increase water supply, but a more normal “wet-dry†regulation schedule went into effect in late 1980 that permitted drying of the marsh. Three droughts followed by reflooding occurred during the 1980s that caused short-term “TP spikes†in the surface water. Lower inflow TP and possible stabilization of phosphorus between the sediment and the water in the marsh after being kept artificially flooded for so long appeared related to the decline in TP. The establishment of BMPs in the EAA have been successful to help in part to achieve phosphorus reduction goals throughout the remaining Everglades. |
| Hypolimnetic Nitrate Treatment to Reduce Internal Phosphorus Loading in a Stratified Lake | Martin Søndergaard; Erik Jeppesen; Jens Peder Jensen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 3 | 2000 | 195 - 204 | Hypolimnetic Nitrate Treatment to Reduce Internal Phosphorus Loading in a Stratified Lake | Nitrate [Ca(NO3)2] was added to the hypolimnion of eutrophic Lake Lyng (10 ha, maximum depth 7.6 m), Denmark, over a 2-year period to study the impact on sediment phosphorus release and to evaluate the potential of hypolimnetic nitrate dosing as a lake restoration method. Dissolved (1995) or granulated (1996) nitrate was added 10 to 11 times at a depth of 5 m during stratification. The total dose was 8 to 10 g N m-2 yr-1. Hypolimnetic nitrate concentration was <0.01 mg N L-1 in years without dosing (1994 and 1997), and reached 1.2 and 2.2 mg N·L-1 in treatment years, respectively. Maximum concentrations of dissolved inorganic phosphorus (DIP) in the hypolimnion were 1.6 to 2.9 mg P·L-1 in untreated years, but were reduced to 0.8 to 1.2 mg P·L-1 in treatment years. Correspondingly, total phosphorus (TP) accumulation in treatment years was 48-77% that of non-treatment years. Dissolved nitrate seemed to reduce TP concentrations more efficiently than granulated nitrate, which sank partly into the loose sediment, and led to lower nitrate as well as lower iron concentrations in the hypolimnion. Lower iron release and/or lower nitrate concentrations resulted from the use of dissolved nitrate, which seemed to reduce precipitation of phosphate with iron and left a larger proportion of particulate phosphorus in the hypolimnion. Ammonia concentrations were higher with nitrate addition, probably due to enhanced mineralization of organic sediment and nitrate ammonification. The results from Lake Lyng suggest that the potential of using nitrate as a lake restoration method in deep lakes suffering from internal loading needs further investigation. |
| Epiphytic Algae on Deep-Dwelling Bryophytes in Waldo Lake, Oregon | N. S. Geiger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 100 - 107 | Epiphytic Algae on Deep-Dwelling Bryophytes in Waldo Lake, Oregon | Benthic bryophyte samples that were retrieved in 1990 from depths of 45 m to 110 m in Waldo Lake were analyzed in 1999 for epiphytes. Rewetting of dried material, most of which was liverworts, indicated extensive colonization by filamentous green and blue-green algae, diatoms and aquatic fungi. Bulbocheate, Oedogonium and Stigonema were the three most common filamentous genera present at nearly each of the six sampling sites. Analysis of diatom associations following the oxidation of dried bryophyte-algae subsamples resulted in identification of 37 taxa within 15 genera of typically attached species. Most species were of the genera Eunotia, Pinnularia and Cymbella. These taxa appeared to be widely distributed on the bottom of the lake, at some stations as much as 30 m to 40 m below the lower depth of the photic zone. |
| Use of a Remote Operated Vehicle and Sonar to Characterize and Estimate the Distribution of Benthic Vegetation in Waldo Lake, Oregon | Randall A. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 108 - 113 | Use of a Remote Operated Vehicle and Sonar to Characterize and Estimate the Distribution of Benthic Vegetation in Waldo Lake, Oregon | Bryophytes that occur in Waldo Lake, Oregon were video-documented and their distribution estimated with sonar. In August 1990, the in situ growth form of the plants was directly observed for the first time using a remote operated vehicle (ROV). Specific growth form of the plants ranged from relatively uniform stand heights (0.25 to 1.0 m) within patches to moderately isolated forms best described as twisted “windrows†or “whorls.†The diameter of the whorls ranged from approximately 0.25 to 0.75 m in diameter and from 5 to 15 m in length. The whorl form was typically in association with patch edges. Plants were found at depths of 128 m (the maximum depth of the lake) and to an upper depth limit of approximately 40 m. The maximum distribution of plants was estimated at 48.9% of the lake area. The use of direct ROV video observation, combined with the sonar, proved to be an acceptable first step in qualitatively describing plant growth and estimating benthic vegetation distribution within the lake. |
| Preliminary Observations of the Benthic Cyanobacteria of Waldo Lake and Their Potential Contribution to Lake Productivity | Alvin C. Johnson; Richard W. Castenholz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 85 - 90 | Preliminary Observations of the Benthic Cyanobacteria of Waldo Lake and Their Potential Contribution to Lake Productivity | Cyanobacteria (blue-green algae) dominate the benthic habitats of Waldo Lake. These photosynthetic microorganisms may be the principal contributors to overall primary production in the lake, although hard data are not yet available. The main biomass of cyanobacteria consists of filamentous, nitrogen-fixing forms, which also produce a yellow-brown, UV-screening pigment (scytonemin) in their extracellular sheaths. This pigment is probably a necessity under these conditions of extreme water clarity in which UV radiation penetrates well. In addition, a conspicuous feature at 1 m to 5 m depths, along much of the shoreline, are living “stromatolites†which resemble shelf-like rock formations, and appear to be formed primarily by the growth of cyanobacteria. Further studies are underway. |
| Deep-water Bryophytes From Waldo Lake, Oregon | David H. Wagner; John A. Christy; Douglas W. Larson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 91 - 99 | Deep-water Bryophytes From Waldo Lake, Oregon | At least thirteen taxa of bryophytes occur between 40 and 128 m depth in Waldo Lake, Oregon. Many taxa exhibit morphological modification precluding positive identification below the level of genus. Liverworts comprise about 98% of the bryomass, the balance being pleurocarpous mosses with trace representation of acrocarps. Predominance of liverworts at extreme depth suggests that they are more viable than mosses under attenuated blue light. All liverworts except one are apparently aquatic forms of upland species. Two mosses are normally upland species, the rest aquatic. Red pigments in some liverwort taxa were maintained as deep as 70 m, but most lost pigment below 40 to 50 m. Sphagnum maintained red pigment as deep as 100 m. Although production of benthic plants would be expected to be exceedingly slow under conditions of low light, low temperatures, limited nutrient availability, and considerable hydrostatic pressure, new growth of 1.5 to 3 cm on liverwort stems approximates annual growth increments observed on upland plants. |
| Growth and Diet of Fish in Waldo Lake, Oregon | Nicola L. Swanson; William J. Liss; Jeffrey S. Ziller; Mark G. Wade; Robert E. Gresswell | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 133 - 143 | Growth and Diet of Fish in Waldo Lake, Oregon | Waldo Lake, located in the Oregon Cascades, is considered to be one of the most dilute lakes in the world. Even with low nutrient concentrations and sparse populations of zooplankton, introduced fish in the lake are large in size and in good condition when compared to fish from other lakes. This apparent anomaly is due to the availability of benthic macroinvertebrates. Taxa found in the stomach contents offish captured in Waldo Lake consist primarily of Chironomidae larvae and pupae, Trichoptera larvae and pupae, amphipods, Ephemeroptera larvae, and Odonata larvae. |
| A History of Fish Management in Waldo Lake, Oregon | Jeffrey S. Ziller; Mark G. Wade | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 144 - 148 | A History of Fish Management in Waldo Lake, Oregon | Trout Oncorhynchus sp. and Salvelinus sp. were released into Waldo Lake beginning in 1889, although releases prior to 1938 are poorly documented. Trout releases were documented for most years between 1938 and 1990. Trout releases were discontinued after 1990. Brook trout are reproducing in the lake and are larger than the average size of brook trout in most lakes in the Oregon Cascade Range. Angling pressure appears to be light and angler catch-rate is poor except during autumn. Future management options include releasing additional fish into the lake, removing fish or leaving things the way they are. |
| Recent Changes in the Zooplankton Assemblage of Waldo Lake, Oregon | Allan Hayes Vogel; Judith Li | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 114 - 123 | Recent Changes in the Zooplankton Assemblage of Waldo Lake, Oregon | Since 1969, two years after introductions of Mysis relicta, the species composition and total density of zooplankton in ultraoligotrophic Waldo Lake have undergone significant changes. During our study, spanning 1969-1998, taxa richness and zooplankter body size decreased. Zooplankton density increased by three orders of magnitude, from <1 m-3 to greater than 600 m-3. Hesperodiaptomus persisted from 1969 through 1998, and appears to be a major determinant in zooplankton dynamics. Rotifers, except Collotheca, were held to extremely low numbers, and cyclopoid copepods were eliminated. Bosminal longirostris, the only cladoceran which is presently common in the limnetic zone of this high altitude lake, exhibits daytime avoidance of the surface waters possibly due to high light intensities. |
| Waldo Lake Macroinvertebrates | Robert L. Hoffman; William J. Liss | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 124 - 132 | Waldo Lake Macroinvertebrates | A total of 41 taxa was collected from nearshore and offshore habitats in Waldo Lake. The highest taxonomic diversity occurred in nearshore habitats which were structurally more complex and heterogenous than offshore habitats. The presence of 39 taxa (Hydridae excluded) in nearshore habitats varied by habitat-type and taxonomic group. Habitat-type was based on substrate-type, and the presence of taxa in nearshore habitats was partially related to the substrate preferences of taxa. A limited number of taxa (i.e., 11) were collected from offshore habitats, which was, in part, a reflection of the relatively homogenous organization and structure of the deeper, offshore habitats of the lake. The percentage of functional feeding groups did not vary much by habitat, and the majority of taxa (i.e., 53%) was classified as predators. Chironomids had the highest relative abundance of all taxa, accounting for 27% of taxa collected in nearshore benthic core samples and 40% of taxa collected in offshore Ekman dredge samples. |
| Thermal and Chemical Properties of Waldo Lake, Oregon | John Salinas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 40 - 51 | Thermal and Chemical Properties of Waldo Lake, Oregon | Thermal and chemical profiles were obtained periodically in ultraoligotrophic Waldo Lake, Oregon during years 1986 through 1999. Profiling was done on a seasonal basis between May and October. During this period the lake becomes thermally well-stratified. Epilimnetic temperatures peak in August, then rapidly diminish in response to decreasing solar radiation. By October, the lake nears autumnal turnover. During winter, the lake freezes over. The lake features an orthograde oxygen profile, and is well-oxygenated to all depths. The lake is highly dilute, as indicated by extremely low values for specific conductance (2.9-5.2 μmhos cm-1) and alkalinity (0.39-0.71 mg·L-1 as HCO3). pH readings were nearly all less than 7.0. Inorganic phosphorus and nitrogen concentrations were mostly less than the minimum detection limit of 1.0 μg·L-1. Dissolved silica concentrations ranged between 0.12 and 0.34 mg·L-1. TDS concentrations averaged 4.04 mg·L-1, with roughly 10% of all test results reported as 0.000 mg·L-1. The cause of the lake's extreme dilution is uncertain, but a major contributing factor may be the fact that the lake is fed entirely by direct precipitation and runoff, with no rivers or permanent streams entering the lake. |
| Waldo Lake History: Prehistoric Period to Present | Paul G. Claeyssens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 25 - 39 | Waldo Lake History: Prehistoric Period to Present | Waldo Lake and vicinity remained essentially an uncharted wilderness until the second half of the Nineteenth Century. The area was largely devoid of its aboriginal inhabitants when Judge John Breckenridge Waldo and his companions spent their summers recreating in the Cascades between 1880 and 1907. These Cascade Mountain respites ultimately led Waldo to call for the area's preservation. But Waldo Lake succumbed to another force in the history of the West, the reclamation movement. In 1905, promoters filed for water rights on Waldo for use as a natural reservoir. The first phase that began in 1905 was a failed attempt to develop the lake as a reservoir for power generation, ending in the mid-1930s as markets declined for hydroelectric power and irrigation water. Federal reclamation projects soon took up the slack, beginning in 1939 with a proposal to divert Waldo Lake out of the Willamette drainage entirely to the Upper Deschutes Project via canals and tunnels through the crest of the Oregon Cascades. Next, the Columbia River project of the U.S. Army Corps of Engineers proposed during the 1940s and 50s depicted Waldo Lake as a vital component of the Upper Willamette system of reclamation installations. By the mid-1950s the twin movements of recreation and wilderness preservation took root and renewed Judge Waldo's call for the protection of and recreation in such places as Waldo Lake. Initially, recreation development held sway, culminating in developed campground facilities in the 1960s. By 1984, the area surrounding Waldo Lake was officially designated as wilderness. |
| Phytoplankton Composition and Distributions in Waldo Lake, Oregon | Jim Sweet | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 63 - 70 | Phytoplankton Composition and Distributions in Waldo Lake, Oregon | The phytoplankton community in Waldo Lake, Oregon is unusual for several reasons, including: (1) phytoplankton diversity is extremely low, with the dinoflagellate Glenodinium neglectum comprising more than 75% of the total phytoplankton; (2) phytoplankton densities are extremely small, with total density and total biovolume averaging 57 algal units ml-1 and 18.5 X 103 μm3 ml-1, respectively; (3) phytoplankton abundance and species composition are nearly uniform throughout the water column, surface to 120 m; (4) several phytoplankton taxa are rare, and some may be new species that have not yet been identified; and (5) picoplankton, which are abundantly present, may be important contributors to the lake's primary production. |
| Waldo Lake, Oregon Chemical Composition: Major Ions, Buffering Capacity, and Nutrient Loading | Peter O. Nelson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 52 - 62 | Waldo Lake, Oregon Chemical Composition: Major Ions, Buffering Capacity, and Nutrient Loading | Previous limnological investigations have identified Waldo Lake as one of the most pristine and chemically dilute lakes in the world. This study focusing on the major ion chemistry of Waldo Lake has confirmed this status. Situated at a topographical divide in the central Oregon Cascades, with a very small watershed (watershed area to lake area ratio = 2) and shallow, porous soils, Waldo Lake chemistry is dominated by precipitation input with relatively less influence from watershed processes. Based on median values, conductivity for Waldo Lake is 3.4 μS·cm-1, while the cation and anion sums are 39 and 29 μeq·L-1, respectively. Acid neutralizing capacity (ANC, also total alkalinity) is 17 μeq·L-1 (0.85 mg·L-1 as CaCO3), indicating that Waldo Lake is very weakly buffered and highly susceptible to acidification from acidic deposition, although there is no evidence that this has occurred. Chloride (14 μeq·L-1) and sulfate (2.1 μeq·L-1) are derived mainly from precipitation (wet and dry deposition), ANC is derived mainly from weathering of watershed base minerals, and base cations (Ca+Mg+Na+K) are derived from both precipitation (two-thirds) and weathering reactions (one-third). Waldo Lake has been classified as ultraoligotrophic based on the extraordinarily low values of primary productivity and nutrient concentrations. Reported nutrient concentrations vary widely due to the extremely low concentrations and insensitivity of methods employed. However, phosphorus has been identified as the limiting nutrient based on algal bioassay methods. Best estimates based on literature data are total P < 3 ug·L-1, about 50% as inorganic P, and total N < 100 to 200 ug·L-1, more than 90% as organic N. There is a net removal of most inorganic N and P from precipitation in the watershed and lake, but watershed and internal lake processes affecting N and P are not well understood. Estimated total phosphorus loading to the lake is 620 kg y-1 and estimated total phosphorus loss from the lake is 81 kg y-1, with about 85% of P retained in the sediments. Waste disposal facilities installed within the last 30 years could substantially increase phosphorus loading and thus alter the ecology of the lake, although remediation measures are now under consideration. |
| Preface | Douglas W. Larson; John T. Salinas; Jim Sweet | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 1 | Preface | |
| Phytoplankton Primary Production and Light in Waldo Lake, Oregon | John T. Salinas; Douglas W. Larson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 71 - 84 | Phytoplankton Primary Production and Light in Waldo Lake, Oregon | Waldo Lake is located in the Willamette National Forest along the west side of Oregon's Cascade Mountain Range. The lake is regarded as one of the most oligotrophic lakes in the world, chemically similar to distilled water, with very low rates of phytoplankton primary production and concentrations of chlorophyll a. Historically, vertical light transmission was considerable, with 1% of the lake's incident solar radiation penetrating to depths greater than 60 m. The lake remains exceedingly clear, as demonstrated by transmissometer profiles and Secchi-disk readings that range between 35 and 40 m. Deep chlorophyll maxima are usually found between 60 and 100 m where measurable light is less than 1% of surface illumination. Conversely, primary production rates and assimilation numbers are maximum in the lake's upper 20 m. Unusually large assimilation numbers in the upper 20 m suggests that the phytoplankton that occupy this stratum are photosynthetically efficient, capable of high rates of production with minimal chlorophyll. There are indications, however, that downward irradiance of blue, green and red light has shifted toward a condition in which the attenuation of blue light has increased more than green and red light. This may be attributed to an increase in phytoplankton density, expressed as a roughly 20-fold increase in phytoplankton primary production over the past 25-30 years. On this basis, Waldo Lake may have shifted from an ultraoligotrophic condition to a more eutrophic state. |
| Geology and Origin of Waldo Lake, Oregon | Gerald L. Black | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 17 - 24 | Geology and Origin of Waldo Lake, Oregon | Volcanism has been active in the central Oregon Cascade Range for at least the last 35 Ma. During that period interactions between the Pacific, North American, and Juan de Fuca plates have produced variations in the composition and rate of volcanism, the landward migration and narrowing of the axis of volcanism, and discreet deformational events. The result of these effects is widespread unconformities that have enabled Cascade Range workers to identify five mappable time-stratigraphic units. Waldo Lake occupies a position in the High Cascades physiographic province. The surrounding rocks are primarily very young (less than 1-2 Ma) basaltic andesite lava flows covered with a thin veneer of glacial drift. Waldo Lake was carved by a northward-moving glacier and is dammed on its southeast side by a lateral moraine. The location of the lake is probably controlled by a large north-south trending down-to-the-east normal fault. |
| Epilogue | Douglas W. Larson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 149 - 150 | Epilogue | |
| Waldo Lake, Oregon: Eutrophication of a Rare, Ultraoligotrophic, High-Mountain Lake | Douglas W. Larson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 16 | 1 | 2000 | 2-16 | Waldo Lake, Oregon: Eutrophication of a Rare, Ultraoligotrophic, High-Mountain Lake | Waldo Lake, Oregon, was described in 1970 as one of the most oligotrophic lakes in the world. But limnological data collected since then indicate that the lake has shifted toward a higher trophic status. This finding is based on three sets of evidence: (1) the spectral distribution of downward irradiance has changed, with blue light now being attenuated more rapidly, while the penetration of both green light and red light has increased; (2) phytoplankton primary production rates have increased 20-fold; and (3) zooplankton have become many times more abundant, and species composition has changed entirely. Although the cause of limnological change is uncertain, investigators believe that it has resulted largely from management and use of the lake. Accordingly, lake visitors have increased dramatically over the past 30 years, from a few hundred visits in 1967 to around 170,000 visits in 1994. Moreover, stocking the lake with 20 million fish between 1938 and 1990 may have disrupted the lake's seemingly fragile ecosystem. Remedial action to save the lake is now being proposed, including (1) repair or removal of sewage-disposal facilities that are possibly defective; (2) tighter restrictions on various lake and watershed uses, and (3) a permanent ban on fish stocking. |
| A Monitoring and Classification System for New Zealand Lakes and Reservoirs | Noel M. Burns; J. Christopher Rutherford; John S. Clayton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 4 | 1999 | 255 - 271 | A Monitoring and Classification System for New Zealand Lakes and Reservoirs | Five variables gave strong indications of change in the trophic state of New Zealand lakes, namely; concentrations of chlorophyll a, total phosphorus and total nitrogen, as well as Secchi depth and dissolved oxygen depletion rate. The New Zealand Lake Monitoring Program, investigated 17 lakes for 3 to 4 years to develop a method for detection of small changes in these five variables and to develop a cost-effective monitoring system for lakes. Two different methods were developed which enabled trends observed separately for variables to be combined into an indicator of change (PAC, Percent Annual Change) and an index of trophic state (TLI, Trophic Level Index). The PAC is a relative indicator that gives the average percent annual change of the trophic state variables, and is an indicator of the magnitude of the change observed. It is calculated from the 5 variables listed above. The TLI is a numerical indicator of lake trophic level, which typically varies from 2 (oligotrophic) to 7 (supertrophic). The TLI can be examined for time trends that generally reflect the changes detected by the PAC relative indicator. These two indicators, when used together, give a good estimate of the probability and magnitude of trophic level change in a lake as well as the trophic level of the lake. Results for all the monitored lakes are given. The PAC and TLI indicators also gave useful results when used to study reservoir monitoring data. |
| Data Quality Control For Lake Temperature by Neural Network | Kang-Ren Jin; Der-San Chen; Lijian Fang; Hui-Chuan Chen; Jay Martin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 4 | 1999 | 272 - 284 | Data Quality Control For Lake Temperature by Neural Network | Lake Okeechobee data are routinely collected by sensors and transcribed from field forms to an electronic format. Occasionally, the effects of extraneous objects, device failure, and human errors may distort these field data. At present, the data are inspected manually by qualified engineers/scientists/technicians to identify abnormalities. This manual process is slow, costly, and sometimes inconsistent among inspectors. This paper presents a neural network approach that can efficiently, effectively, and consistently mimic human expertise in identification of days that contain abnormal water temperature. The approach begins with training 12 backpropagation neural networks (one per month) using the normal and abnormal daily patterns selected by the domain expert. The trained networks can then be used for identification in lieu of human experts. A total of 623 days of data from Lake Okeechobee were used: 241 days for training and 382 days for testing the networks. The results for the test data indicate that this approach achieves 98% accuracy in rejecting abnormal data and 95% accuracy in accepting normal data. |
| Changes in Benthos and Three Littoral Zone Fishes in a Shallow, Eutrophic Ontario Lake Following the Invasion of the Zebra Mussel (Dreissena polymorpha) | J. L. Mercer; M. G. Fox; C. D. Metcalfe | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 4 | 1999 | 310 - 323 | Changes in Benthos and Three Littoral Zone Fishes in a Shallow, Eutrophic Ontario Lake Following the Invasion of the Zebra Mussel (Dreissena polymorpha) | We assessed changes in the benthic community, and in the feeding, growth and polychlorinated biphenyl (PCB) concentrations in three littoral zone fishes (pumpkinseed, Lepomis gibbosus, bluegill, Lepomis macrochirus and yellow perch, Perca flavescens) in Rice Lake, Ontario, following the invasion of zebra mussels (Dreissena polymorpha) in 1994. Zebra mussel settling density on ceramic tiles peaked at 449,000·m-2 in 1996, and adult mussel densities averaged 854·m-2 at the Curtis Point reference site. Mean summer chlorophyll a concentrations were still high in 1995 and 1996 (14.6 μg/L), and were not significantly different than those recorded in 1986-88. Non-dreissenid benthic invertebrate biomass did not increase significantly relative to a pre-invasion year, but amphipod biomass did increase significantly. There was no evident shift in the diet of die three littoral zone fishes from zooplankton to benthic invertebrates. The pumpkinseed was the only species to have experienced an increase in growth rates following the zebra mussel invasion. Contrary to our predictions, significant declines in the concentration of PCBs were observed in the muscle of pumpkinseed, although differences in fish sizes may have confounded PCB analysis. Overall, there did not appear to be a negative impact of zebra mussel invasion on any of the three fish species, and pumpkinseeds appeared to benefit from this invasion. Our results indicate that shallow, productive lake ecosystems may either be resistant to many of the zebra mussel-induced changes experienced in deeper, less eutrophic lakes, or that such changes may take more than three years before becoming evident. |
| Contrasting Relationships Between Nutrients, Chlorophyll a and Secchi Transparency in Two Shallow Subtropical Lakes: Lakes Okeechobee and Apopka (Florida, USA) | Karl E. Havens; Hunter J. Carrick; Edgar F. Lowe; Michael F. Coveney | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 4 | 1999 | 298 - 309 | Contrasting Relationships Between Nutrients, Chlorophyll a and Secchi Transparency in Two Shallow Subtropical Lakes: Lakes Okeechobee and Apopka (Florida, USA) | Ten years of monthly water quality data were compared from two large shallow lakes in Florida, USA - Lakes Okeechobee and Apopka. Seasonal changes in trophic state index (TSI) values and log-log regression models relating total phosphorus (TP), total nitrogen (TN), chlorophyll a (CHLA), and Secchi transparency (SD) were considered. The objective was to quantify the extent to which empirical models might vary due to the heterogeneous nature of benthic-pelagic coupling that can occur in shallow lakes. In the offshore region of Lake Okeechobee, TP and SD-based TSI values increase dramatically during winter, while CHLA-based TSI declines. These changes coincide with the windy season in south Florida, when average wind velocities can exceed 20 km h-1. Resuspension of bottom sediments occurs and this reduces light penetration to the extent that the growth of phytoplankton is inhibited. During summer, winds are calm, and these conditions occur less often. Log-log regression models of CHLA vs. TP have a negative slope during winter and a positive slope during summer in offshore Lake Okeechobee. The slope of SD vs. CHLA models displays the opposite seasonal pattern. Seasonal changes are considerably muted in the near-shore region, where sediments are more consolidated and where shallower depths reduce the severity of light suppression of phytoplankton growth. The magnitude of seasonal variation in TSI values in Lake Apopka is muted, perhaps because seasonal variation in wind velocity is less than in the region of Lake Okeechobee. Hypereutrophic levels of nutrients, CHLA, and SD occur year-round. The log-log regression models of CHLA vs. TP and CHLA vs. TN are highly significant, and light availability does not appear to limit rates of algal production. Frequent resuspension events may occur, but negative effects on phytoplankton may be mitigated by: (1) shallower depth; (2) a greater presence of viable algae in the surface sediments that might “seed†the water column with phytoplankton; (3) high concentrations of soluble nutrients in sediments that might stimulate algal growth; and (4) lower concentration of light-attenuating inorganic particles than in Lake Okeechobee. The results indicate that a high degree of variability in both the seasonal patterns and relationships among nutrients, CHLA, and transparency can occur in shallow subtropical lakes, even when they share common features (e.g., geographic location, large size, wind patterns). This finding has practical implications regarding the use of regression models in the context of shallow lake management. Models may be quite useful on a lake-by-lake basis (e.g., in Lake Apopka they have successfully been used in eutrophication management), but considerable care should be taken when generalizing models to other lake ecosystems. |
| A Review of the Effects of Hypolimnetic Oxygenation on Lake and Reservoir Water Quality | Marc W. Beutel; Alex J. Horne | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 4 | 1999 | 285 - 297 | A Review of the Effects of Hypolimnetic Oxygenation on Lake and Reservoir Water Quality | Hypolimnetic aeration is an increasingly common management technique that aerates the hypolimnion while preserving thermal stratification. While most hypolimnetic aeration systems use air as an oxygen source, use of pure oxygen is growing. Potential benefits of hypolimnetic oxygenation include maintenance of an oxygenated source of cool water to meet consumer and environmental needs, decreases in internal nutrient loading, inhibition of sediment release of problematic reduced compounds, and maintenance of summertime habitat for cold-water fish, zooplankton and zoobenthos. A number of short-term experimental oxygenation systems were operated in the 1970s, but large scale systems were not implemented until the 1980s. Deep oxygen injection systems have been operating in Lakes Sempach, Baldegg, and Hallwil, Switzerland, since the early 1980s to ameliorate cultural eutrophication. Deep oxygen injection has also been used to increase DO in hydroelectric releases from a number of large reservoirs in the southern USA. A comprehensive study of physical, chemical and biological impacts of deep oxygen injection was performed at Amisk Lake, Alberta, from 1988-1993. In die early 1990s, downflow oxygen bubble contact chambers (Speece Cones) were installed in Newman Lake, Washington, and Camanche Reservoir, California, mainly to improve the quality of cold-water fishery habitat. Compared to hypolimnetic aeration, oxygenation results in higher hypolimnetic dissolved oxygen levels, lower levels of induced oxygen demand, and maintenance of more stable thermal stratification. Operational experiences over the past two decades confirm that hypolimnetic oxygenation is a successful management strategy with numerous water quality benefits. |
| Dosing Alum to Wisconsin Lake Sediments Based on in vitro Formation of Aluminum Bound Phosphate | Emil Rydin; Eugene B. Welch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 4 | 1999 | 324 - 331 | Dosing Alum to Wisconsin Lake Sediments Based on in vitro Formation of Aluminum Bound Phosphate | The dose of aluminum (Al) needed to deplete mobile inorganic sediment phosphorus (P) [loosely-sorbed P and Iron (Fe)-bound P] and transform it to Al-P was estimated in vitro in Lake Delavan, Wind Lake, and Bass Bay sediments. The formation of Al-P was logarithmically related to increased Al added as buffered alum. Results of the in vitro treatments were compared with the observed effect on sediment-P composition from the 1991 alum treatment (12 g Al·m-2) in Lake Delavan. That 1991 dose resulted in the formation of 2.2 g P·m-2, measured as Al-P, which was apparently the maximum amount of P that could be adsorbed with that alum dose. Based on in vitro alum additions, 150 g Al·m-2, twelve times that added, would have been required to nearly deplete mobile P in surface (0-4 cm) sediment of Lake Delavan (16 m). Wind Lake contained less mobile P, so a dose of 80 g Al·m-2 was required to remove mobile P in sediments from its deep hole (14m), while an addition of only 20 g Al·m-2 was needed for sediments from its average depth (3 m). Similar to Wind Lake, sediments from the deep hole (6 m) in Bass Bay required 90 g Al·m-2. These doses were estimated based on a ratio of added Al to adsorbed P of 100:1 (by weight), which was determined in vitro and was consistent for the three lakes. These doses would also be enough to adsorb significant amounts of P moving to the sediment surface from sediment layers deeper than 4 cm and are all less than those determined by water column alkalinity. The mobile sediment-P method could be used to estimate dose based on the 100:1 ratio of Al added to formed Al-P and measured mobile P (loosely-sorbed P + Fe-P) in the top 4 cm of sediment. |
| A Simple Field Technique For Accurate Reaeration Estimates in Aquatic Systems | Thomas V. Belanger; John A. Meyer; Marc G. von Canal; Mani V. Desik | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 3 | 1999 | 185 - 199 | A Simple Field Technique For Accurate Reaeration Estimates in Aquatic Systems | Obtaining accurate reaeration rate estimates in water bodies remains a primary concern for limnologists, oceanographers and other researchers because of its importance in water quality modeling and productivity studies. A simple and accurate field technique to measure reaeration was developed and is based on the fact that sparingly soluble compounds will dissolve in water as a function of turbulence, and therefore this dissolution rate can be directly related to the reaeration rate across the air/water interface. Detailed laboratory testing of the dissolution rate of solid benzoic acid probes, under a large range of turbulence conditions that approximated natural systems, indicate that the dissolution rate (VS) of the probe was a good predictor of the surface transfer rate (KL). Linear regressions of VS at numerous wind speeds (R2 = 0.93), non-breaking wave heights (R2 = 0.89) and flow rates (R2 = 0.89) all indicated significant relationships. The KL/Vs relationship for breaking waves (R2 = 0.86) was slightly less significant than for non-breaking waves (R2 = 0.89), but maybe related to the problem of obtaining representative dissolved oxygen values in our wave tank experiment. Combined wind/wave experiment reaeration rates were higher than individual wind and wave results, as expected, but results were not additive. This is likely due to the increased surface area available for wind impacts, due to the formation of the waves, coupled with complex surface agitation patterns. Further testing with an established probe design under a greater range of conditions is needed before wide scale use in the field can occur. |
| Applying a Western Water Quality Management Approach in Post-Soviet Eastern Bloc Europe | Steven R. Butkus; Gezja M. Timĉák; Samuel Pa≗enovský | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 3 | 1999 | 200 - 208 | Applying a Western Water Quality Management Approach in Post-Soviet Eastern Bloc Europe | The Total Maximum Daily Load (TMDL) management process established in the Clean Water Act of the United States is applied to a reservoir in the Eastern Slovak Republic. The TMDL is a water quality management approach sometimes used in the United States. With the recent change in environmental perspective in Post-Soviet Eastern Bloc Europe, the TMDL model was tested for relevancy in reservoir water quality management in this region. The TMDL management process is based on a technical analysis that quantifies pollutant sources. The analysis is used to test alternative pollution control strategies that address a mix of both wastewater discharges and non-point sources. The analysis shows that in order to meet standards, domestic wastewater must be removed and the most efficient nonpoint source control measures implemented. The information is being used by a non-governmental organization in a series of community forums to decide which pollution control options should be implemented. These meetings focus on the use of local empowerment to make decisions. A citizen volunteer water quality monitoring program has been established to help test the effectiveness of the pollution controls. Although it is too soon to see measurable environmental results, the application of the management process, patterned after the TMDL approach, depends on the grassroots support being generated. Local citizens are now becoming more interested in their environment, and are developing the capacity to act. |
| A Reservoir Model For Use in Regional Water Resources Management | Daniel L. Tufford; Hank N. McKellar Jr.; Joseph R. V. Flora; Michael E. Meadows | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 3 | 1999 | 220 - 230 | A Reservoir Model For Use in Regional Water Resources Management | Lake Wateree (5,548-ha, 382.4 106m3), a eutrophic reservoir on the South Carolina Piedmont, is downstream from a large urban area that is rapidly expanding. A 7-segment WASP5 eutrophication model was developed to enhance our understanding of the water quality dynamics of the lake. We used monitoring data from 3 time intervals for model calibration (1993), verification (1995), and scenario analysis (1991-1996). Parameters calibrated (Kolmogorov-Smirnov 2-sample goodness-of-fit test; p<.05) were chlorophyll a, ammonia-N, nitrate-N, dissolved oxygen, and total phosphorus. Mainstem segments tested well (19 of 20). The embayment segment tests (3 of 5) suggest a different ecological subsystem that requires further study to effectively characterize. Sensitivity analysis shows the lake is hydro biochemically similar to other mainstem reservoirs, but also that phytoplankton production may be nitrogen limited. Nutrient loading analysis to predict the possible effect of increased urbanization upstream (15% increase from point sources; 75% from combined point and nonpoint sources) suggests the reservoir could exceed the 40 μg·L-1 threshold indicating severe eutrophication. |
| Isolation and Characterization of the Natural Colloidal Material From the Fox River | Nicolle S. Tulve; Thomas C. Young | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 3 | 1999 | 231 - 238 | Isolation and Characterization of the Natural Colloidal Material From the Fox River | Resuspension of aquatic sediments with HOCs (hydrophobic organic contaminants) can disrupt existing sorption equilibria and cause HOC desorption, and increase the exposure of water column biota to HOCs. Resuspension can also increase levels of aqueous colloidal material in the overlying water column. Furthermore, because colloidal material partly determines the transport and ultimate fate of sediment-derived HOCs, physical and chemical characterizations of sediment colloids that are subject to resuspension are necessary to assess the full impact of activities that disturb contaminated sediments (e.g., dredging, navigation, chemical treatment, high flow events). Colloidal material extracted from lower Fox River sediments was analyzed for chemical (total organic carbon (TOC), elemental and mineralogical analyses, isoelectric point (pHIEP)) and physical (particle size distribution (PSD), solids and moisture content, surface area) characteristics, and subjected to batch aggregation studies under controlled conditions of ionic strength (10-4-10-2 M in 1:1 and 1:2 electrolyte solutions), pH (3-7), and colloid concentration (4-10 mg L-1 as TOC equivalents). The characterization and experimental results indicate that the extracted colloidal material aggregates in a manner consistent with existing double-layer models of the solid-solution interface in aquatic systems, most notably including faster aggregation (i) in the 1:2 than in the 1:1 electrolyte solution, (ii) at acidic pH (near pHIEP), and, (iii) at high colloid concentration. The PSD of the colloidal aggregates tended to be relatively broad, indicating the potential for relatively short- as well as long-range dispersion of colloidally bound HOCs derived from resuspended Fox River sediments. |
| Long-Term Water Quality and Biological Effects of Alum Treatment of Lake Morey, Vermont | Eric Smeltzer; Richard A. Kirn; Steven Fiske | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 3 | 1999 | 173 - 184 | Long-Term Water Quality and Biological Effects of Alum Treatment of Lake Morey, Vermont | Lake Morey received one hypolimnetic treatment with alum and sodium aluminate in 1986 to reduce the occurrence of algae blooms caused by internal P loading. Thirteen years of post-treatment monitoring have documented a sustained improvement in water quality in the lake. Comparison of pre-treatment (1977-1985) and post-treatment (1986-1998) data indicated that significant improvements occurred in all water quality variables measured, including spring TP (reduced 66%), summer photic zone TP (reduced 68%), summer photic zone Chi a (reduced 61%), summer Secchi disk transparency (increased 79%), late summer hypolimnetic TP (reduced 83%), and late summer hypolimnetic DO (increased 193%). The one-time alum/aluminate treatment of Lake Morey has thus far succeeded in breaking a cycle of sediment P release and re-precipitation that was initiated during an earlier period in the lake's history. Relative weight loss was observed in samples of large yellow perch during the 3 years immediately following the treatment. Yellow perch condition returned to pre-treatment levels by 1991. Toxicity from elevated dissolved aluminum concentrations in the water column during the summer of treatment may have caused the observed weight loss in fish. The benthic macroinvertebrate community in the upper hypolimnion experienced a 90% decline in density during the year immediately following the alum treatment. The benthic community recovered during subsequent years with density and taxa richness generally exceeding pre-treatment values, possibly in response to improved hypolimnetic DO conditions. |
| Calibration of Phosphorus Export Coefficients for Total Maximum Daily Loads of Massachusetts Lakes | Mark D. Mattson; Russell A. Isaac | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 3 | 1999 | 209 - 219 | Calibration of Phosphorus Export Coefficients for Total Maximum Daily Loads of Massachusetts Lakes | In an effort to develop Total Maximum Daily Loads of total phosphorus for hundreds of Massachusetts lakes we reanalyzed the land use export coefficients of previously published diagnostic/feasibility studies. Typically, literature values for phosphorus loading per unit area of land use overestimate total phosphorus loading to Massachusetts lakes. We used a stagewise regression technique to screen a variety of models and to select export coefficients that were reasonable, based on the literature, and which offered a good fit to the data. The final model was verified by predicting phosphorus loadings to an independent set of Massachusetts lakes with an average error of 36 percent. The process has been automated with the use of the Arcview Geographic Information System computer system and digital maps of land use. With additional data, the model can also be used to predict lake total phosphorus concentrations under a variety of proposed land use management plans. |
| An Analysis of the Trophic State of Clinton Lake | Shih H. Wang; Donald G. Huggins; Frank deNoyelles; Werner S. Kolln | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 3 | 1999 | 239 - 250 | An Analysis of the Trophic State of Clinton Lake | The trophic state of Clinton Lake was assessed. Typical longitudinal gradients were observed with nutrient concentrations (TN, TP, NO3-N, NH4-N, PO4-P) decreasing from the riverine areas of the reservoir to the main basin. The TN:TP ratio went from 6.7 in the riverine zones to 14.2 in the main basin. The reservoir was eutrophic according to all the criteria assessed. Using growing season means for the main basin: chlorophyll a = 16 μg·L-1 > 10 μg·L-1, TP = 39 μg·L-1 >20 μg·L-1, TN = 0.52 mg·L-1 > 0.50 mg·L-1, Secchi disk depth = 1.13m < 2 m. Practices aimed at reducing phosphorus and sediment loadings are suggested to improve water quality. |
| Evaluation of Transparency and Light Attenuation by Aquashadeâ„¢ | John D. Madsen; Kurt D. Getsinger; R. Michael Stewart; John G. Skogerboe; David R. Honnell; Chetta S. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 2 | 1999 | 142 - 147 | Evaluation of Transparency and Light Attenuation by Aquashadeâ„¢ | Aquashadeâ„¢, a colorant and dye registered by the US Environmental Protection Agency (USEPA) for use in aquatic environments to manage plant growth, does not reduce the visibility of water that otherwise would meet safe swimmming standards. This product was examined for its potential impact on underwater visibility in surface waters used for recreational swimming. Aquashadeâ„¢ treatments of 0, 1, and 5 mg L-1 were evaluated in 3-m deep outdoor tanks containing reservoir water. Transparency and light attenuation were examined using a Secchi disk and an underwater photo synthetically active radiation (PAR) meter. In the first experiment, filtered lake water was used, while in the second, bentonite clay was added to provide a light transparency of approximately 1 m. In filtered lake water, Aquashadeâ„¢ treatments (1 mg L-1 and 5 mg L-1) reduced light transparency by approximately 10% and 30%, respectively, but the transparency (272 and 194 cm, respectively) was well above typical international (100 cm) and state (33 cm) standards for safe swimming. In the trial with clay turbidity, the 1.0 mg L-1 Aquashadeâ„¢ treatment was not significantly different in transparency when compared with the untreated reference, but the 5 mg L-1 treatment reduced transparency to 67 cm (31%). Aquashadeâ„¢ absorbed light from 550 nm to 650 nm, with peak absorbance in the 630 nm range. Field measurements of Aquashade spectral attenuation matched that observed in the laboratory. While treatments at the allowable level of 1 mg L-1 will reduce transparency, the effect is small compared to inorganic or algal-induced turbidity that can occur in surface waters. |
| Evaluation of Surface Sampling for Estimates of Chlorophyll, Total Phosphorus, and Total Nitrogen Concentrations in Shallow Florida Lakes | Claude D. Brown; Daniel E. Canfield Jr.; Roger W. Bachmann; Mark V. Hoyer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 2 | 1999 | 121 - 132 | Evaluation of Surface Sampling for Estimates of Chlorophyll, Total Phosphorus, and Total Nitrogen Concentrations in Shallow Florida Lakes | A study of 11 north-central Florida lakes was conducted to determine if surface sampling (0.5 m) provided the same estimates of chlorophyll, total phosphorus, and total nitrogen concentrations as samples collected with a Kemmerer bottle at 1 m and 2 m, and a 2-m pvc tube sampler (integrated column). The absolute values of differences between surface estimates of chlorophyll, total phosphorus, and total nitrogen concentrations and estimates obtained by use of other sampling methods were small and from a practical standpoint would not preclude the use of the surface estimates. Only a few statistically significant differences were detected for some individual lakes. For this group of Florida lakes, the greatest amount of variability in estimates was attributed to differences among lakes (≥95%). Surface estimates were also highly correlated (r ranged from 0.95 to 0.98) to estimates obtained by other methods. Because surface sampling is simple, cost-effective, and provides comparable estimates of chlorophyll, total phosphorus, and total nitrogen concentrations, surface water sampling is recommended if a large number of Florida lakes are to be sampled. |
| Impact of Aquatic Plant Management Methodologies on Eurasian Watermilfoil Populations in Southeast Wisconsin | Daniel R. Helsel; Stanley A. Nichols; Robert S. Wakeman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 2 | 1999 | 159 - 167 | Impact of Aquatic Plant Management Methodologies on Eurasian Watermilfoil Populations in Southeast Wisconsin | Declines and increases in Eurasian watermilfoil populations (Myriophyllum spicatum L.) throughout North American Lakes have highlighted the need for long-term studies. Similarly, understanding the long-term implications of different aquatic plant management techniques (e.g., mechanical harvesting, chemical treatment, no management) is a crucial component of aquatic plant management. We examined the aquatic plant communities and management techniques for nine Southeast Wisconsin lakes for a period of 6 to 9 years prior to 1996 to assess the long-term population changes of Eurasian watermilfoil subjected to different management regimes. In eight of the nine lakes, the Eurasian watermilfoil populations either declined in frequency or remained constant; while in seven of the nine lakes the native aquatic plant community either increased in average number of plant species per sample location or remained constant The long-term aquatic plant community information for these nine case study lakes suggest that “typical†aquatic plant management activities does not negatively effect the lake-wide aquatic plant community; although changes, or the lack of changes, of an aquatic plant community cannot be directly attributed to management activities. |
| Temporal Variations of Water Quality and the Taxonomic Structures of Phytoplankton and Zooplankton Assemblages in Mountain Lakes, Mount Rainier National Park, Washington USA | Gary L. Larson; C. David McIntire; Ruth W. Jacobs; Robert Truitt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 2 | 1999 | 148 - 158 | Temporal Variations of Water Quality and the Taxonomic Structures of Phytoplankton and Zooplankton Assemblages in Mountain Lakes, Mount Rainier National Park, Washington USA | A synoptic inventory of physical and chemical properties and plankton assemblages of 27 mountain lakes was conducted at Mount Rainier National Park in 1988. From 1990-1993, die opportunity was presented to resurvey six of these lakes to determine inter-annual change within die set of characteristics surveyed in 1988. If changes were evident, a second objective was to provide guidance to park management about the value of a long-term lake monitoring program. Secchi-disk clarity, water temperature, and pH of the lakes in 1988 were within the range of values obtained between 1990 and 1993. Conductivities and concentration of nutrients in some lakes were not consistent in 1990-1993 with the values recorded in 1988. Although the dominant phytoplankton taxa in die lakes varied among years, die taxa in individual lakes were in consistent among years, with die exception of two lakes. Rotifer assemblages were consistent among years, but most of die lakes exhibited dramatic changes in some years, as did crustacean zooplankton assemblages. Suggestions were made about die need for a long-term monitoring program to evaluate die status and trends of park lakes. |
| Floristic Quality Assessment of Wisconsin Lake Plant Communities with Example Applications | Stanley A. Nichols | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 2 | 1999 | 133 - 141 | Floristic Quality Assessment of Wisconsin Lake Plant Communities with Example Applications | Floristic quality is a rapid assessment metric designed to evaluate the closeness of the flora of an area to undisturbed conditions. To be useful for a variety of monitoring applications it has to be calibrated for local conditions. Based on data from 554 lakes, this paper develops a floristic quality metric for Wisconsin lake plant communities and calibrates it for ecoregional and lake type differences. The Northern Lakes and Forests ecoregion had the highest floristic quality with flowages having the highest number of species and lakes having the highest average coefficient of conservatism (). Floristic quality in lakes and flowages in the North Central Hardwoods region and the Southeastern Till Plain region were not significantly different and were combined into a single group. Their floristic quality was intermediate between the Northern Lakes and Forest groups and the final group that was a combined Driftless Area and Mississippi River Backwater lake group. When applied to a limited number of examples the floristic quality index appears to give reasonable results but more trials of use under well documented disturbance conditions is needed to determine its sensitivity. |
| Setting Water Quality Goals for Restoration of Lake Apopka: Inferring Past Conditions | Edgar F. Lowe; Lawrence E. Battoe; Michael Coveney; David Stites | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 2 | 1999 | 103 - 120 | Setting Water Quality Goals for Restoration of Lake Apopka: Inferring Past Conditions | Lake Apopka is a large (12,500 ha), hypertrophic lake in central Florida which is the subject of a state-sponsored restoration program. We used three quantitative methods in concert with an analysis of the history and general character of the lake and drainage basin to infer the past conditions. We specifically examined two past conditions: 1) pristine (before any major anthropogenic disturbance) and 2) antecedent (before a specific, major anthropogenic disturbance). For Lake Apopka the pristine condition ended in the 1890s when a canal was dug which lowered the elevation for surface water outflow. The antecedent condition ended in the late 1940s when most of the lake's 8,900 ha of floodplain marsh was drained for farming. History, general lake and basin characteristics, and the quantitative analysis indicate that Lake Apopka was mesotrophic; with clear-water and native, submersed macrophyte beds; in both the pristine and antecedent conditions. The three quantitative methods (reference lakes, empirical models, and a loading model) were used to infer the ranges of most probable values in the antecedent condition for total phosphorus, chlorophyll a and Secchi depth. These ranges were 32-51 mg·m-3 for total phosphorus, 8-38 mg·m-3 for chlorophyll a, and 1.39-0.76 m for Secchi depth. Lake Apopka has had a history strikingly similar to that described for Dutch lakes affected by cultural eutrophication with proliferation of macrophytes in the clearwater state preceding a rapid transition to the turbid, algal-dominated state induced by a large increase in the phosphorus loading rate. |
| Results of Simulated Temperature Control Device Operations on In-Reservoir and Discharge Water Temperatures Using CE-QUAL-W2 | R. Blair Hanna; Laurel Saito; John M. Bartholow; Jeff Sandelin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 2 | 1999 | 87 - 102 | Results of Simulated Temperature Control Device Operations on In-Reservoir and Discharge Water Temperatures Using CE-QUAL-W2 | A computer model of the operation of the Shasta Lake temperature control device (TCD) confirms the device's ability to maximize power production and simultaneously reduce summer discharge water temperatures. The TCD's in-reservoir thermal effects were consistent for a wide range of hydrologic conditions. Changes in the thermal structure were most pronounced in the hypolimnion, where summer water temperatures were about 1°C cooler, but up to 5°C warmer in the late fall compared to without-TCD conditions. Epilimnetic effects of the TCD were negligible, with mean temperature differences between with- and without-TCD conditions in the top 20 meters of the reservoir of less than 0.5°C throughout die year. The zone of impact of the TCD was unexpectedly large; in-reservoir temperature changes were seen up to 20 km upstream of the dam in all three major branches. However, in-reservoir temperature changes did not carry over into subsequent years with continued TCD use. Discharge temperature targets were not met by simple, month-to-month changes in selective withdrawal elevations, but more complex TCD operational schemes did provide the required outlet temperatures throughout me year. This more complex operation involved mixing waters from multiple shutter outlets and varying the mix daily. The application of bioenergetics equations to the temperature output from CE-QUAL-W2 indicates that TCD operations may not have significant direct effects on water temperature-driven scope for growth of rainbow trout and smallmouth bass in the reservoir. |
| Initial Findings Regarding Changes in Phyto- and Zooplankton Composition and Abundance Following the Temporary Drawdown and Refilling of a Shallow, Hypertrophic South African Coastal Lake | William R. Harding; Susan Wright | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 1 | 1999 | 47 - 53 | Initial Findings Regarding Changes in Phyto- and Zooplankton Composition and Abundance Following the Temporary Drawdown and Refilling of a Shallow, Hypertrophic South African Coastal Lake | Marked changes in phyto- and zooplankton assemblage and abundance were observed in a regulated, shallow, hypertrophic lake following temporary drawdown and refilling. Despite significant increases in the ambient concentrations of nitrogen and phosphorus, levels of chlorophyll-a fell from a mean of 260 νg·L-1 before drawdown and refilling to 70 μg·L-1 thereafter. The concentration of chlorophyll-a fell to 3 μg·L-1 during aspring clearwater phase previously unobserved in Zeekoevlei, but observed in other, adjacent shallow lakes. This clearwater phase was characterized by an increase in mean water transparency from 0.3 to 0.75 m. A marked swing towards an algal assemblage comprised of chlorophyte species occurred during aseasonal period historically-dominated by cyanophytes. Levels of pH and dissolved oxygen declined with the reduced phytoplankton activity in the lake. The zooplankton assemblage was dominated by large-bodied cladocerans, this in contrast to dominance by cyclopoid copepods. It is hypothesized that reduced grazing pressure on the zooplankton, brought about by loss offish from the lake, and in combination with other, as yet unidentified forcing functions, contributed to the observed changes. It is suggested that the implementation of the temporary drawdown and refilling of the lake served to reinitiate seasonal biotic characteristics which would have been common in this and other shallow seasonal waters prior to the introduction of water level regulation. It is further suggested that this procedure should be repeated on an annual basis in order to further entrench beneficial effects and improvements in water quality, and without loss of recreational amenity value. |
| Localized Changes in Transparency Linked to Mud Sediment Expansion in Lake Okeechobee, Florida: Ecological and Management Implications | Karl E. Havens; R. Thomas James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 1 | 1999 | 54 - 69 | Localized Changes in Transparency Linked to Mud Sediment Expansion in Lake Okeechobee, Florida: Ecological and Management Implications | During the last decade, water quality monitoring data have indicated declines in Secchi transparency in the southwestern pelagic region of Lake Okeechobee. Sampling stations that previously displayed intra-annual variation in Secchi depths from 0.2 to 2.7 m now display Secchi depths that never exceed 1.0 m. The historical changes in transparency occurred abruptly, and the recent low transparencies have been very stable. Ratios of Secchi/total depth indicate that light often may have reached the lake bottom (ratios > 0.5, and as high as 1.0) prior to the new stable state, but never reached the bottom afterwards (ratios <0.3). Secchi depth vs. chorophyll a relationships also have changed in the southwestern pelagic region. Stations previously displayed significant inverse log relationships between the two variables, similar to what is observed today at near-shore, sand-bottomed sites in Lake Okeechobee. In recent years, there has been no relationship between Secchi depth and chlorophyll a. This is similar to the mud-bottomed central pelagic region, where abiotic turbidity controls light attenuation. One explanation for the sudden changes in Secchi transparency is migration of mud sediments from mid-lake towards the southwestern shore. A comparison of sediment maps constructed in 1975 and 1988 indicates that the area of lake bottom covered by mud sediment increased from approximately 30 to 44% over that period. The major direction of expansion was to the southwest, and the postulated movement coincided closely with dates when Secchi declines were observed at water quality monitoring stations. The declines in transparency that have occurred in the southwest near-shore region of Lake Okeechobee may have important ecological and societal implications. This near-shore region is the primary foraging and nesting habitat for commercial and sport fish, wading birds, and migratory water fowl. Losses of submerged plant communities due to reduced light penetration may adversely affect these communities. In addition to a present goal of external P load reduction, lake managers should give consideration to in-lake methods that might prevent further water quality degradation in near-shore regions. Because water depth can act synergistically with turbidity to bring about the changes described above, one option is a substantial draw-down of the lake, followed by actions to prevent the prolonged high lake stages that recently have led to submerged plant declines. Selective dredging of sediments from the southwest region of the lake might also be considered, although this would likely be only a short-term solution to the water quality problems, given the remaining large source of mud at the center of the lake. |
| Effects of Phosphorus Reduction on Water Quality: Comparison of Alum-Treated and Untreated Portions of a Hypereutrophic Lake | John C. Holz; Kyle D. Hoagland | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 1 | 1999 | 70 - 82 | Effects of Phosphorus Reduction on Water Quality: Comparison of Alum-Treated and Untreated Portions of a Hypereutrophic Lake | The effects of a reduction in total phosphorus concentration on the water quality and plankton community structure in a 86-ha hypereutrophic sandpit lake with high internal phosphorus loading were assessed by dosing an isolated 4.6-ha section of the lake with 34,065 L (dose = 10 mg Al·L-1) of liquid aluminum sulfate (alum). During the three summers following treatment, hypolimnetic total dissolved phosphorus, epilimnetic total phosphorus, and eplimnetic total nitrogen were decreased by 97%, 74%, and 36%, respectively, in the treated section. Secchi depth was 134% greater in the treated area. Alum treatment also increased the volume of usable fish habitat by 22%, as the depth of the 3.0-mg/l dissolved oxygen isocline was 52% deeper in the treated portion than in the untreated portion. Total phytoplankton biovolume decreased by 40% and chl a concentration by 65% in the treated area. Although cyanophytes continued to dominate in die treated area, there was a shift in relative abundance from cyanophytes to bacillariophytes and chlorophytes, especially during the second summer after treatment. By the second post-treatment summer, daphnid biomass increased substantially and there was a subtle shift in relative abundance from copepods to daphnids. Overall, alum was extremely effective in controlling sediment phosphorus release rates and lowering water column phosphorus concentrations and thus improving water clarity, reducing phytoplankton biomass, shifting phytoplankton species composition from cyanophyte dominance toward bacillariophytes and chlorophytes, increasing daphnid biomass, and increasing usable fish habitat. |
| Ecosystem Rehabilitation | G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 1 | 1999 | 1-4 | Ecosystem Rehabilitation | Restoration of damaged or extirpated aquatic and terrestrial ecosystems has been proposed as one means of meeting Clean Water Act goals, and as a way to reduce further ecological deficits and economic losses. However, restoration means a return to pre-disturbance conditions and relies on historic landscapes or ecosystems as models. It is the most demanding of management paradigms and implies complete re-creation of a system equivalent to the model. Restoration represents the extreme on a continuum of management protocols and is valuable as an ideal. In most cases, it is impractical, uncalled for, or even impossible. Rehabilitation is the repair and replacement of essential ecosystem structures and functions in the context of ecoregional attainability in order to achieve specified objectives. It is analogous to medical rehabilitation and emphasizes return to an achievable resemblance of prior conditions and makes no pretense of accomplishing absolute authenticity. It is a process that many ecologists are doing. It excludes activities solely oriented to human centered needs, such as spraying and cleanups. Damage and loss of freshwater ecosystems are apparent. The consequences are just beginning to be understood. I urge the establishment of ecologically coherent Federal rehabilitation programs. |
| Estimating Phosphorus Concentrations Following Alum Treatment Using Apparent Settling Velocity | John C. Panuska; Dale M. Robertson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 1 | 1999 | 28 - 38 | Estimating Phosphorus Concentrations Following Alum Treatment Using Apparent Settling Velocity | The apparent settling velocity (Vs) is a term used in empirical, steady-state, mass-balance lake models to represent the net phosphorus flux from the water column. The Vollenweider (1969) mixed-reactor lake model was rearranged and used to calculate Vs values for total phosphorus (TP) for three lakes treated with alum to reduce the internal flux of P to the water column (Delavan Lake, Wisconsin; Lake Morey, Vermont; and West Twin Lake, Ohio). An analysis of Vs values was conducted using data from these three lakes for both the pre- and post-alum treated conditions. Analysis of Vs values for both the pre- and post-alum conditions in Lake Morey and West Twin Lake resulted in a post-treatment mean Vs value of 7 ± 2.0 m·yr-1. The effect of the alum treatment, although short-lived in Delavan Lake, resulted in a mean post-treatment Vs value of 3.4 ± 0.3 m·yr-1. The consistency in the post-treatment Vs values in Lake Morey and West Twin Lake is used to demonstrate a predictive analysis method for water column TP concentrations in lakes following a successful treatment of the anoxic sediment area with alum. Additional pre- and post-alum in-lake and watershed loading data are needed to advance this concept into a management model. |
| Relationships Between Total Phosphorus Concentrations, Sampling Frequency, and Wind Velocity in a Shallow, Polymictic Lake | Charles G. Hanlon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 1 | 1999 | 39 - 46 | Relationships Between Total Phosphorus Concentrations, Sampling Frequency, and Wind Velocity in a Shallow, Polymictic Lake | The effect of sampling frequency and wind velocity on estimates of total phosphorus (TP) concentrations were evaluated in Lake Okeechobee, Florida, a shallow, polymictic lake. It was hypothesized that estimates of TP would be affected by sampling frequency because the lake's P-rich bottom sediments are frequently resuspended during wind events. However, differences in estimates of annual mean TP were small (< 5 %) when daily, weekly, bi-monthly, and monthly sampling frequencies were compared. In contrast, estimates of monthly mean TP often varied by 20 to 30 percent among sampling frequencies and differences in monthly maximum and minimum TP values commonly varied by 50 to 250 μg·L-1. Bottom sediments were most likely to be resuspended during the windy season (November-April) when calculated threshold wind velocities were exceeded more than 40 percent of the time. On a monthly basis, wind velocity explained as much as 70 percent of the daily variability in TP during the windy season. In comparison, threshold velocities were exceeded less frequently during the calm season (May - October) and wind velocity only accounted for 5 to 25 percent of the daily variability in TP. The effects of wind-driven mixing events on the chemical and physical attributes of shallow lakes and the influence of sampling frequency on estimates of these attributes should be considered when designing a monitoring program to evaluate short and long-term trends in water quality. |
| Effectiveness and Longevity of Phosphorus Inactivation with Alum | Eugene B. Welch; G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 15 | 1 | 1999 | 5-27 | Effectiveness and Longevity of Phosphorus Inactivation with Alum | Effectiveness and longevity of alum treatments were evaluated in 21 lakes (or lake basins) across the United States; 9 were polymictic and 12 were dimictic. Effectiveness was judged from reductions in lake TP (total phosphorus) and internal loading rate, as well as chlorophyll a (chl a), both initially and over periods ranging from 4 to 20 years following treatment. Internal loading rate was reduced in six of nine polymictic lakes/basins by an average of two-thirds, and lake TP was reduced by about one-half, which persisted for 5-11 years. Internal loading rate in dimictic lakes (7 of 7 with adequate data) remained reduced by an average of 80% for 4 to 21 years (average 13 yrs). For the six polymictic lakes, in which treatment was effective, chl a decreased by an average of two-thirds initially, but was about 40% less than die pre-treatment level after 5 to 11 years. Chl a decreased in seven dimictic lakes by an average of 57% initially and 42% after 5-18 years. In some cases, response was independent of alum treatment because the trophogenic zone was affected more by external than internal P loading. At West Twin Lake, OH, nutrient diversion was more important than control of P release from hypolimnetic sediments in improving surface water quality. The significance of vertical P entrainment, as well as external loading, should be considered before treating dimictic lakes. Alum was initially ineffective in two polymictic lakes and was effective only for a few years in a third, apparently due to interference from macrophytes. Dense macrophytes may have caused uneven floe distribution or sediment P was recycled from below the floe layer through plant senescence and decay. Where macrophytes did not interfere, treatments were usually effective for at least 8 years and up to 11 years in polymictic lakes; an expectation of 10 years longevity is considered reasonable for unstratified lakes. Several dimictic lakes showed effectiveness/longevity of internal loading control for at least 13 and up to 18 to 20 years; an expectation of 15 years longevity seems reasonable for dimictic lakes. The decline in treatment effectiveness could have been due to bioturbation, or to sinking and burial of the aluminum floe over time, as evidenced by a distinct Al layer located at about 20 cm after 16 years in West Twin Lake, OH. A direct relation between dose and treatment longevity, as well as an inverse relation between dose and sediment P release rate, was apparent in the dimictic lakes. |
| Lake Typology Influences on the Phosphorus-Chlorophyll Relationship in Subarctic, Alaskan Lakes | Jim A. Edmundson; Stan R. Carlson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 4 | 1998 | 440 - 450 | Lake Typology Influences on the Phosphorus-Chlorophyll Relationship in Subarctic, Alaskan Lakes | We examined the relationship between chlorophyll a (chl a) and phosphorus (P) concentration among 52 clear, 21 organically stained (yellow colored), and 14 glacially turbid (silty) lakes in Alaska. A weak correlation (r2 = 0.14) exists between seasonal mean chl a and total phosphorus (TP) with most of die error related to the glacial lakes. However, nonbiologically available P represents 52% of TP in glacial lakes compared to only 12% in clear lakes and 15% in stained lakes. TP corrected for nonbiologically available phosphorus (CTP) explains 55% of the variation in chl a across lake typologies. However, chl a response to CTP is greater in clear lakes compared to stained lakes. Despite having higher CTP concentrations, the CTP-chl a relationship is not significant for the glacial lakes, suggesting the influence of other factors on chl a. Considering clear, stained, and glacial lakes together, adding turbidity and color along with CTP accounts for 60% of the variation in chl a. The additional variability explained (32%) by the multivariate model represents a composite measure of the influence of lake typology on the TP-chl a relationship. Despite the comparatively narrow range in chl a (0.1 to 9.9 μg · L-1) and CTP concentrations (1.7 to 36.2 μg · L-1) and the wide range in turbidity (0.2 to 48.6 NTU) and color (2 to 55 platinum-cobalt units), our multivariate model provides a foundation for defining specific lake typology criteria (other than P) that can better predict chl a. Application of our model will benefit assessment of regional changes in water quality, trophic status, and fish habitat across a variety of lake types. |
| Paleolimnological Study of Metal and Nutrient Changes in Spanish Harbour, North Channel of Lake Huron (Ontario) | Aruna S. Dixit; Sushil S. Dixit; John P. Smol; W. Bill Keller | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 4 | 1998 | 428 - 439 | Paleolimnological Study of Metal and Nutrient Changes in Spanish Harbour, North Channel of Lake Huron (Ontario) | The Spanish Harbour (Lake Huron, Ontario) and the lower Spanish River are designated as an Area of Concern (AoC) by the International joint Commission. This paleolimnological study was initiated to provide the missing historical data for the past conditions of the AoC for the Spanish Harbour Remedial Action Plan (RAP), which has been developed to restore and protect the water quality of Spanish Harbour. The study has shown that anthropogenic activities in the watershed have changed the water quality considerably. The changes started about 1930 when metal concentrations started to increase in die basin, and reached maximum levels by ca. 1970. Since about 1970, metal concentrations have declined significantly. The recovery is closely associated with the reductions in emissions from the Sudbury smelters since die early 1970s. The timing of the increase in metal contamination and the post-1970 recovery in Spanish Harbour are similar to the geochemical trends seen in many Sudbury lakes. Although metal concentrations have decreased, the area has continued to receive high nutrient inputs from the drainage basin. Based on the fossil diatom and chrysophyte assemblages, nutrient enrichment appears to have increased in the harbour since the mid-1970s. |
| Tracking the Cultural Eutrophication History of Collins Lake (Southeastern Ontario, Canada) Using Paleolimnological Techniques | Tammy L. Karst; John P. Smol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 4 | 1998 | 456 - 465 | Tracking the Cultural Eutrophication History of Collins Lake (Southeastern Ontario, Canada) Using Paleolimnological Techniques | Paleolimnological analyses using diatoms preserved in a 34-cm sediment core from the presently eutrophic Collins Lake, southeastern Ontario, were used to determine the lake's natural trophic state, as well as the impacts of past watershed activities on water quality. The presence of eutrophic diatoms (especially Fragilaria crotonensis and Aulacoseira ambigua) and low chrysophyte cyst to diatom frustule ratios in the pre-setdement section of the sediment core suggested that the lake was naturally somewhat productive. Further eutrophication occurred, as demonstrated by relative increases in eutrophic diatom taxa such as Aulacoseira granulata, F. crotonensis, and Asterionella formosa, with the onset of European settlement, deforestation of the catchment vegetation, and agricultural practices. Finally, in the early to mid-1970s, land-use changes from primarily rural to more residential and recreational resulted in further nutrient enrichment of Collins Lake, likely from increased point-source nutrient inputs from private septic systems and household phosphate-based fertilizers. Total phosphorus concentrations inferred using a quantitative diatom-based transfer function confirmed the above qualitative assessments of the recent trophic state changes of Collins Lake. However, the naturally-productive nature of Collins Lake, as inferred from this paleolimnological study, contradicts the results obtained from applying the Ontario Ministry of the Environment's Ontario Trophic Status Model (TSM), which hindcast oligotrophic conditions for the lake, prior to European settlement. These paleolimnological data have important implications for lake management issues. |
| Influence of Trophic Status on Larval Fish Abundance in Four Southeastern United States Reservoirs | R. John; H. Hoxmeier; Dennis R. DeVries | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 4 | 1998 | 451 - 455 | Influence of Trophic Status on Larval Fish Abundance in Four Southeastern United States Reservoirs | While the relationship between productivity and adult fish yield has been extensively studied, it has been viewed as a static relationship, whereas interactions among organisms and trophic levels change dramatically with the life stage of the interacting organisms. As such, little attention has been given to mechanisms that might control this relationship. Toward this end, we examined the influence of trophic status on larval fish abundance in four reservoirs in Alabama and Georgia, USA. Larval fish communities in eutrophic reservoirs were dominated by gizzard shad (Dorosoma cepedianum) and threadfin shad (D. petenense), while crappie (Pomoxis spp.) and sunfish (Lepomis spp.) contributed a relatively larger percentage of the fish community in the oligotrophic reservoir, similar to findings for older fishes from previously published work. However, while larval shad and lepomid sunfish were more abundant in eutrophic than in oligotrophic reservoirs, larval crappie showed the opposite trend. Why larval shad and lepomid sunfish appeared to be controlled by lower trophic levels while larval crappie appeared to be controlled by upper trophic levels was not clear. However, when our larval fish abundance results were compared with previous results for older fishes, they suggest that while the mechanism controlling abundance and eventual year-class strength may differ across species, actual abundance and year-class strength within species is likely set during early life. |
| Assessing Water Quality in Catawba River Reservoirs Using Landsat Thematic Mapper Satellite Data | Robert M. Cox Jr.; Randall D. Forsythe; Gene E. Vaughan; Larry L. Olmsted | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 4 | 1998 | 405 - 416 | Assessing Water Quality in Catawba River Reservoirs Using Landsat Thematic Mapper Satellite Data | This study investigates the potential of satellite-based remote sensing to assess water quality in the 11 reservoirs of the Catawba River basin. Near-simultaneous acquisition of both Landsat TM (Thematic Mapper) data and in situ water quality observations (turbidity, secchi disk depth, chlorophyll and surface temperature), in May of 1995, provided a statistical foundation for the development of algorithms that convert TM reflectance to each water quality parameter. The conversion models defined for turbidity, secchi disk depth, chlorophyll (power law function) and temperature (linear function) were used to produce digital cartographic products that depict the distribution of each parameter in the 11 reservoirs. A analysis of error demonstrates that accurate quantitative data products can be produced from Landsat TM imagery for the surface waters of the major reservoirs in this system with a spatial resolution of 30 m for turbidity and secchi disk depth, and a 120-m resolution for surface temperature. Landsat TM appeared to have an inadequate spectral resolution for the quantitative assessment of chlorophyll. In this study, an additional experiment was performed in October 1995 to evaluate the applicability of the reflectance-based conversion algorithms to TM data acquired at other times and from other reservoirs. Though not quantitatively conclusive, the predicted values derived by the conversion algorithms were as consistent with ground observations for all water quality parameters except chlorophyll as that seen in the initial experiment. |
| Simulation of Dairy Best Management Practices Using the AGNPS Model | Steven W. Coffey; Daniel E. Line | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 4 | 1998 | 417 - 427 | Simulation of Dairy Best Management Practices Using the AGNPS Model | Agricultural nonpoint sources of nutrients and sediment threaten the quality of the Cane Creek Reservoir, a Piedmont North Carolina water supply lake, in the absence of detailed monitoring, the Agricultural NonPoint Source Pollution Model (AGNPS) was used to predict water runoff and the delivery of dissolved and sediment-attached nitrogen and phosphorus to stream tributaries to the lake. The findings of the distributed parameter modeling study included four dairy watersheds (53 to 195 ha) and were part of a management plan developed to protect the impoundment from further degradation. Annual total nitrogen and total phosphorus export predictions for entire farms ranged from 1.0 to 3.7 and 0.7 to 1.8 kg · ha-1 for current conditions. Simulated exports of total nitrogen and total phosphorus were between 0.9 to 3.1 and between 0.4 to 1.6 kg · ha-1 due to best management practices (BMPs) installed. In addition, simulation studies of smaller areas such as individual pastures, cropland fields, and feedlots showed substantial nutrient export reductions due to refinements in dairy manure management, depending upon the site. For one feedlot needing structural improvements, simulated BMPs reduced annual total nitrogen and total phosphorus loads from 74 and 21 kg · ha-1 to 0.85 and 0.4 kg · ha-1. Also included are recommendations for additional BMPs and the cost for implementation. |
| Dynamics in Phosphorus Retention in Wetlands Upstream of Delavan Lake, Wisconsin | Dale M. Robertson; John F. Elder; Gerald L. Goddard; William F. James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 4 | 1998 | 466 - 477 | Dynamics in Phosphorus Retention in Wetlands Upstream of Delavan Lake, Wisconsin | A phosphorus budget was constructed for Delavan Lake Inlet, a perennial riverine wetland with submersed and floating aquatic vegetation in southeastern Wisconsin, to better understand the phosphorus dynamics in natural wetlands and the role of wetlands in lake-rehabilitation efforts. During the growing season, the inlet served as a net source of phosphorus, primarily due to the release of phosphorus from the sediments. More phosphorus was released from the sediments of the inlet (600 kg) than was input from the upstream watershed (460 kg). This release was caused by high pH associated with high photosynthetic activity. During the remainder of the year, the inlet served as a net sink for phosphorus, retaining 6% of die phosphorus input from the watershed. Over the entire year, this wetland was a net source of over 500 kg of phosphorus to downstream Delavan Lake. A constructed riverine wetland upstream of Delavan Lake Inlet demonstrated a similar periodic release of phosphorus. However, in this case, the summer release of phosphorus was less than that trapped during the remainder of the year. The constructed wetland served as a net sink for approximately 20% of the input phosphorus on an annual time scale. The role of existing and constructed wetlands as phosphorus traps is complex. Wetlands can act as a source or a sink for phosphorus depending on the ambient conditions in die wetland. Howa wetland fits into a rehabilitation plan depends upon its net retention efficiency and the importance of the periodic releases of phosphorus to downstream waters. |
| Chemical Exchange at the Sediment-Water Interface of Cannonsville Reservoir | Michael J. Erickson; Martin T. Auer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 266 - 277 | Chemical Exchange at the Sediment-Water Interface of Cannonsville Reservoir | Rates of chemical exchange at the sediment-water interface of Cannonsville Reservoir were determined using intact sediment cores. Reference sites for coring were selected based on the results of a surficial sediment survey. Higher levels of volatile suspended solids, chemical oxygen demand, total organic carbon, total nitrogen, and total phosphorus were noted at deep water stations proximate to the dam and near the discharge of the West Branch of the Delaware River (WBDR, the reservoir's major tributary). Rates of sediment oxygen demand (SOD), measured at 20 °C at the three reference sites, ranged from 0.66 to 1.67 gO2 · m-2 · d-1 with a mean±s.d. of 1.06±0.23 gO2 · m-2 · d-1. No statistically significant variation in SOD with location in the reservoir was noted. No phosphorus (P) release was detected under aerobic conditions. Rates for cores incubated under anaerobic conditions ranged from 9.2 to 15.6 mgP · m · -2 · d-1, with a reservoir-wide mean±s.d. of 12.9 ± 2.2 mgP · m-2 · d-1. P-release rates at P-enriched sites (surficial sediment survey) were higher than at mid-reservoir locations with lower sediment-P. Rates of ammonia-nitrogen (NH3-N) release ranged from 19.6 to 43.2 mgNH3-N · m-2 · d-1 with a reservoir-wide mean ± s.d. of 31.8 ± 7.2 mgNH3-N · m-2 · d-1. A general trend of decreasing sediment NH3-N release with distance from the discharge of the WBDR was noted. Rates of sediment exchange measured here are consistent with those reported for other systems of a similar degree of nutrient enrichment and trophic state. Downcore profiles of sediment chemistry suggest that while organic carbon and nitrogen are undergoing diagenesis in the reservoir (SOD is exerted and NH3-N release is observed), P deposited to the sediment remains in the particulate form and is not recycled. The sediments are, however, rich in the forms of particulate P which support release. High rates of P exchange maybe expected if trophic state conditions deteriorate further, resulting in extended anoxia. |
| Phosphorus Bioavailability and P-Cycling in Cannonsville Reservoir | Martin T. Auer; Katherine A. Tomasoski; Mary J. Babiera; Melanie L. Needham; Steven W. Effler; Emmet M. Owens; Jeff M. Hansen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 278 - 289 | Phosphorus Bioavailability and P-Cycling in Cannonsville Reservoir | Algal bioassays and chemical fractionation analyses were applied in determining the bioavailability of phosphorus (P) discharged to Cannonsville Reservoir from its major tributary, the West Branch of the Delaware River (WBDR) and in reservoir bottom sediment. Soluble phase (soluble reactive and dissolved organic) P discharged by WBDR was found to be 100% bioavailable, in a single, dry-weather sample. Tributary particulate-phase P bioavailability varied with hydrologic conditions: 48% for a dry-weather sample and 25% for a wet-weather sample. The P-bioavailability of reservoir bottom sediments (24%) was comparable to that for the wet-weather tributary sample. Phosphorus released over the course of the tributary bioassays came from the Fe/Al-P and extractable biogenic-P pools, while that generated in reservoir bottom sediment bioassays originated entirely from the Fe/Al-P pool (despite the presence of a significant extractable biogenic-P fraction). WBDR sediment had approximately two times more total phosphorus (TP) and five times more bioavailable phosphorus (BAP) than did the reservoir's bottom sediment. Losses in particulate P between introduction and export occurred largely from the extractable biogenic-P fraction. Kinetic coefficients developed here (fraction bioavailable, solubilization coefficient) were used within the context of a nutrient-phytoplankton model to identify the sources of P ultimately realized by the algal community. Tributary soluble P accounted for 91-97% of the realized algal P. Tributary particulate P has a lesser impact due to its smaller loading contribution, lower bioavailability and because much of it is lost to sedimentation, adsorption following solubilization, and export. Depending upon the TDP:PP ratio in the tributary and bioavailability characteristics of the particulate phase P, soluble P contributes 4-7 times more P to the algal available pool than does the particulate phase. |
| Allochthonous Contributions of THM Precursors to a Eutrophic Reservoir | Carol Stepczuk; Angela B. Martin; Patricia Longabucco; Jay A. Bloomfield; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 344 - 355 | Allochthonous Contributions of THM Precursors to a Eutrophic Reservoir | Temporal patterns in trihalomethane (THM) precursor concentrations (measured as THM formation potential, THMFP) and loads are documented for West Branch Delaware River (WBDR), the primary tributary for Cannonsville Reservoir, NY, and a secondary tributary, for a 12-month period. The analysis was supported by routine and runoff event-based (11 events) sampling at the mouth of WBDR, and 3 synoptic surveys along its length. Ninety-eight percent of the precursors from WBDR formed chloroform, and 94% were in a dissolved form (DTHMFP). Temporal variations on a seasonal scale, as well as during runoff events, are reported. The range in DTHMFP was 151 to 325μg · L-1. Increases in precursor concentration observed (from 140 to 240 μg · L-1) moving from upstream toward the mouth of WBDR may reflect anthropogenic contributions. A time series of daily loads of DTHMFP from WBDR to die reservoir is presented for the April-December interval of 1995. The volume-weighted concentration for this period was 228 μg · L-1. Dissolved organic carbon had only limited value as a surrogate measure of THM precursor concentration. |
| A Limnological Analysis of Cannonsville Reservoir, NY | S. W. Effler; A. P. Bader | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 125 - 139 | A Limnological Analysis of Cannonsville Reservoir, NY | A limnological analysis of Cannonsville Reservoir, NY, is presented that focuses on features related to primary production. Monitoring data collected in 1995, a major drawdown year for the impoundment, and long-term data (since 1974), are evaluated. The reservoir demonstrates eutrophic characteristics in most summers, though upper mesotrophic conditions have been observed in some years. The concentration of chlorophyll is found to be the most reliable indicator of trophic state for the impoundment, as tripton (non-living particulate material) interferes with the measures of Secchi disc transparency and total phosphorus (P) concentration as indicators. Evidence is presented that the sediment resuspension process introduced tripton into the water column in 1995 as the reservoir was drawn down. Oxygen was depleted from the hypolimnion during the summer months of 1995; anoxia prevailed above the deep-water sediments for about 1 month. However, a major release of P from the sediments did not occur during this period. Evidence is presented that nitrogen became limiting to phytoplankton growth in mid-summer, and that a sink process(es) operates for die soluble reactive P released in the hypolimnion from the decomposition of organic material. Longitudinal gradients in trophic state indicators and other features of water quality prevail. Bounds for the riverine, transition, and lacustrine zones are presented; the lacustrine zone represents about 80% of the full reservoir volume. |
| Characteristics and Origins of Metalimnetic Dissolved Oxygen Minima in a Eutrophic Reservoir | Steven W. Effler; Rakesh K. Gelda; MaryGail Perkins; David A. Matthews; Emmet M. Owens; Carol Stepczuk; Andrew P. Bader | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 332 - 343 | Characteristics and Origins of Metalimnetic Dissolved Oxygen Minima in a Eutrophic Reservoir | The occurrence and characteristics of metalimnetic dissolved oxygen (DO) minima are documented, the origins of the phenomena are evaluated, and the contribution of DO consumption in this layer to overall consumption below the epilimnion is resolved, for Cannonsville Reservoir, NY. The analysis utilizes detailed vertical profiles of temperature and DO collected in the lacustrine zone of the reservoir over the 1988-1997 interval, profiles of scalar irradiance and fluorescence measured in 1995, calculations of vertical profiles of phytoplankton production and respiration of DO for selected conditions, and mass balance analyses for DO in the metalimnion and hypolimnion of the reservoir over the 10-year record. The metalimnetic minimum is shown to be a recurring phenomenon in the reservoir, that was conspicuously manifested in late summer in each of the 10 years. The position of the minimum below the water surface has been rather uniform in mid-summer but other features, including the extent of DO depletion, have varied greatly. Respiration of relatively high concentrations of phytoplankton biomass within the metalimnion, located below the compensation depth, contributed to the development of the observed minima. The high phytoplankton concentrations of the metalimnion probably are associated with slowed descent rather than interflow(s). On average, ~ 70% of the DO consumption exerted below the epilimnion over the 1988-1997 interval occurred in the metalimnion. The average DO consumption rate in this layer, normalized for layer volume, was 80 mg·m-3·d-1. It was necessary to accommodate the important effects of export and exchanges between layers (entrainment flows) associated with reservoir operations in the mass balance framework used to estimate consumption rate(s). |
| Thermal and Heat Transfer Characteristics of Cannonsville Reservoir | E. M. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 152 - 161 | Thermal and Heat Transfer Characteristics of Cannonsville Reservoir | Observations of the spatial and temporal distribution of temperature in Cannonsville Reservoir over the 1988-1995 period are reviewed, with emphasis on 1994 and 1995. The dominant spatial variations in temperature are in the vertical direction (thermal stratification), with modest spatial variations along the longitudinal axes of the basin. Longitudinal temperature variations were greatest in the spring, with shallow, upstream waters being warmer than at deeper sites downstream near the dam. Diurnal temperature variations of the surface waters of the reservoir were generally less than 2 °C. The variations of temperature of two major reservoir tributaries are also documented. The tributaries are generally warmer than reservoir surface waters in spring, but are cooler through most of the summer and the fall. Diurnal fluctuations in tributary temperature may be significant, with day-night changes as large as 15 °C observed for Trout Creek. A reservoir heat budget calculation for 1995 indicates that inflow/outflow and water surface heat transfer are both important in affecting temperature variations of the reservoir. Direct measurements of incident solar radiation at the reservoir site for a single year allowed calibration of a predictive relationship that may be used in hydrothermal modeling. Estimation of empirical coefficients in predictive expressions for other components of water surface heat transfer was performed using the net water surface heat transfer computed from the heat budget. The implications of these findings for predictive hydrothermal modeling of the reservoir are discussed. |
| Hydrologic Analysis and Model Development for Cannonsville Reservoir | Emmet M. Owens; Rakesh K. Gelda; Steven W. Effler; James M. Hassett | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 140 - 151 | Hydrologic Analysis and Model Development for Cannonsville Reservoir | The hydrology of Cannonsville Reservoir, a water supply and flow augmentation reservoir for the City of New York, is analyzed. Measurements of components of the hydrologic budget of the reservoir over the entire 30 years of operation are reviewed. The largest tributary is gauged near its discharge to the reservoir; all others are ungauged. Water surface elevation and outflow, in the form of spillway flow, direct releases for flow augmentation, and drinking water withdrawal are monitored. Multiple uses of the reservoir and variations in runoff common to the region result in strong seasonal and interannual variations in hydrology. Spillway flow typically occurs in late winter and spring, and is rare in summer and early fall. Releases, to meet minimum flow requirements in the Delaware River downstream, generally occur only in summer and early fall. Drinking water withdrawal is relatively uniform throughout the year. On average, spill, dam releases, and withdrawal for the water supply have represented 40%, 32%, and 28%, respectively, of the outflow of the reservoir over the 30 years. Reservoir water surface elevation is generally greatest in the spring and lowest in the fall. Reductions in maximum depth of 40% and in storage volume of 75% have occurred in dry years. A hydrologic model was developed to maintain a hydrologic balance and estimate surface inflows from the ungauged portion of the watershed. While estimates based on a simple ratio of ungauged flow to gauged flow may be used for annual averages, a more complex budget calculation based on a 10-day averaging period was used to provide a time series of daily average ungauged inflow. The average annual flushing rate for the 30 years was 2.6 y-1 while the range was 1.9 to 3.6 y -1. Use of the entire 30 years hydrologic record is recommended to support forecasting with hydrothermal and water quality models. |
| A Strategy for Reservoir Model Forecasting Based on Historic Meteorological Conditions | E. M. Owens; S. W. Effler; S. M. Doerr; R. K. Gelda; E. M. Schneiderman; D. G. Lounsbury; C. L. Stepczuk | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 322 - 331 | A Strategy for Reservoir Model Forecasting Based on Historic Meteorological Conditions | A strategy for the application of linked watershed and reservoir models in the analysis of water quality management proposals for a water supply reservoir is presented. This strategy is based on the use of a long-term historical record of meteorological data, so that die predicted changes in water quality may be evaluated by considering the variations in streamflow, material loading, reservoir heat transfer and mixing associated with natural variations in meteorological conditions. Model simulations for a baseline condition and for several management proposals involving point source nutrient control, nonpoint source nutrient reduction, and reservoir operations are presented. The predictions are presented as distributions of the frequency of occurrence of selected annual statistics of nutrient loading, reservoir stratification, and reservoir water quality. Simulations for Cannonsville Reservoir indicate that reductions in phosphorus loading from wastewater treatment plants in the watershed would have a greater impact on summer average chlorophyll concentrations than nonpoint phosphorus control, and that reservoir operations that result in a decrease in reservoir drawdown result in improved reservoir water quality. |
| Gradients and Dynamics in Downward Flux and Settling Velocity in Cannonsville Reservoir | S. W. Effler; C. M. Brooks | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 213 - 224 | Gradients and Dynamics in Downward Flux and Settling Velocity in Cannonsville Reservoir | Seasonal and longitudinal patterns in downward fluxes and settling velocities of selected particulate constituents, including suspended solids (TSS), organic carbon (C), nitrogen (N), phosphorus (P) and chlorophyll (Cr), are documented for eutrophic Cannonsville Reservoir, NY, for the stratification period of 1995, based on analyses of particulate concentrations in the epilimnion and sediment collected in cylindrical traps deployed below the epilimnion at six different sites. Strong longitudinal gradients in downward flux were observed for all the constituents; the highest rates prevailed in the upstream/riverine zone, the lowest in the downstream/lacustrine zone. These gradients in deposition were driven by gradients of the same form in both the concentrations of the particulate constituents in the epilimnion and the settling velocities of these materials. Substantial temporal variability was observed in particulate species concentrations, and the downward fluxes and settling velocities of these constituents. The mean settling velocities of Cr, particulate organic C, P, and TSS for the lacustrine zone of the reservoir were 0.17, 0.32, 0.88, and 0.73 m · d-1, respectively. The distinctly higher values for TSS, organic C, and P, compared to Cr reflect contributions to deposition from non-phytoplankton particles, probably associated with sediment resuspension processes and allochthonous inputs. The fluxes and settling velocities reported here are important in supporting the development and testing of related water quality models for the reservoir. |
| Development and Parameterization of a Kinetic Framework for Modeling Light- and Phosphorus- Limited Phytoplankton Growth in Cannonsville Reservoir | Martin T. Auer; B. Forrer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 290 - 300 | Development and Parameterization of a Kinetic Framework for Modeling Light- and Phosphorus- Limited Phytoplankton Growth in Cannonsville Reservoir | A mechanistic framework for simulating phytoplankton growth kinetics in lakes and reservoirs is described. The framework is based on published physiological submodels describing light- and phosphorus-limitation of phytoplankton growth and the relationship between the rates of growth and respiration. The physiological submodels were tested and related kinetic coefficients defined through a program of field measurement and laboratory experimentation. Values for kinetic coefficients were determined using the natural phytoplankton assemblage of Cannonsville Reservoir, a part of the New York City drinking water supply system. The suite of submodels was shown to satisfactorily represent the phytoplankton response to variation in the light and nutrient regime of the reservoir. Efforts to test submodels and determine kinetic coefficients on a site-specific basis are believed to enhance the credibility and reliability of the model framework in its application for water quality management. |
| Sediment Resuspension in Cannonsville Reservoir | S. W. Effler; R. K. Gelda; D. L. Johnson; E. M. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 225 - 237 | Sediment Resuspension in Cannonsville Reservoir | The operation of the sediment resuspension process in Cannonsville Reservoir, NY, a eutrophic flow-augmentation and water supply impoundment for New York City, during the major drawdown year of 1995 is documented. Methodologies used in the assessment included transmissometer profiling; electron microscopy-based physical and chemical characterization of individual particles from the water column, sediments and the principal tributary; analysis of sediment trap collections; and mass balance calculations for total suspended solids (TSS). The resuspension process had several pronounced manifestations. First was the development of a conspicuous benthic nepheloid layer (BNL) which, by mid-summer, extended nearly 10 m above the bottom at one location. Second was the increase in the concentration of inorganic particles in the upper waters as the reservoir was drawn down. These particles, ultimately derived from the watershed, caused increases in turbidity. Third was the measurement of higher downward fluxes in a near-bottom sediment trap compared to a below-thermocline trap deployment and throughout the water column during the fall mixing period. Finally, the TSS deposition rate greatly exceeded estimates of TSS retention for the reservoir. The resuspension phenomenon has important management implications for this and other water supplies because it represents a source of turbidity, and because the resuspended particles interfere with widely adopted signatures of phytoplankton production. Sediment resuspension is probably promoted in this reservoir by the drawdown of the water surface. |
| Analysis of Material Loading to Cannonsville Reservoir: Advantages of Event-Based Sampling | Patricia Longabucco; Michael R. Rafferty | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 197 - 212 | Analysis of Material Loading to Cannonsville Reservoir: Advantages of Event-Based Sampling | Eight years of monitoring data are reviewed and analyzed for the West Branch of the Delaware River, the major tributary supplying Cannonsville Reservoir: 3 years are from the early 1980s, the other 5 years include 1991-1996. Phosphorus, nitrogen, and sediment loads were measured at the mouth of the West Branch using an approach of intensified sampling during runoff events and routine sampling during baseflow intervals. Total river loads of nutrients and sediment are reported on a water-year basis; selected analytes are reported on a monthly basis. Additionally, phosphorus inputs are partitioned into nonpoint and point source loads. The point source phosphorus load decreased about 75% during the 1990's study period primarily due to upgrades at the largest municipal wastewater treatment plant in the watershed. Annual nonpoint source phosphorus loads were variable over the study period: dissolved phosphorus ranged from 6,600 kg · y-1 to 20,800 kg · y-1, while particulate phosphorus ranged from 7,400 kg · y-1 to 115,000 kg · y-1. Most of the annual loads of nonpoint source phosphorus, sediment and ammonia were delivered during runoff events. The loads determined through event-based sampling are compared to loads calculated using two other load estimation approaches: an export coefficient technique and fixed frequency sampling combined with the loading software FLUX. The natural variation in nonpoint source loads is examined in the context of setting management goals for improving water quality. |
| Development and Testing of One-Dimensional Hydrothermal Models of Cannonsville Reservoir | Emmet M. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 172 - 185 | Development and Testing of One-Dimensional Hydrothermal Models of Cannonsville Reservoir | Two one-dimensional (vertical) hydrothermal models of Cannonsville Reservoir, a water supply serving New York City, were developed and tested. A two-layer model, capable of hindcasting temperature dynamics for two (epilimnion, hypolimnion) completely-mixed, variable-volume layers, was calibrated by determining die seasonal variation of the vertical heat transfer coefficient. This model was used only to hindcast temperature for the spring-fall period of 1995. A multi-layer model (average layer thickness 1.5 m over 50 m maximum depth) was developed that has the capability of forecasting stratification and vertical transport conditions in the reservoir based on specified meteorologic, hydrologic, and reservoir operation conditions. As a part of calibration, the multi-layer model was used to hindcast stratification and vertical transport conditions for the continuous period 1988 through 1995. The model accurately reproduced observed temperature profiles and other observed features such as thermocline depth, rate of hypolimnetic heating, and duration of stratification. A sensitivity analysis indicated that vertical transport of heat to the lower waters of the reservoir in summer is largely associated with advection caused by release of water at the base of the dam; vertical diffusion plays a relatively small role. Model forecasts indicate that stratification characteristics are relatively insensitive to intake location (three intakes over a range of elevation are available), but are more sensitive to the rate of dam release. |
| A Framework for Modeling the Fate and Transport of Giardia and Cryptosporidium in Surface Waters | Martin T. Auer; Susan T. Bagley; David A. Stern; Mary J. Babiera | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 393 - 400 | A Framework for Modeling the Fate and Transport of Giardia and Cryptosporidium in Surface Waters | The feasibility of modeling the environmental fate and transport of cysts and oocysts of the protozoan pathogens Giardia lamblia and Cryptosporidium spp. in surface waters is examined. A kinetic and modeling framework successfully applied for fecal bacteria is considered for this application. The model utilizes a mass balance approach and accommodates inputs from tributary loads and sediment resuspension, losses to sedimentation and inactivation and mass transport. Recommendations are provided for the design of a program of field monitoring and experimental studies which would support model development. Requirements for model application are considered within the context of Cannonsville Reservoir, a component of the New York City drinking water supply system. |
| Calibration, Verification, and an Application of a Two-Dimensional Hydrothermal Model [CE-QUAL-W2(t)] for Cannonsville Reservoir | Rakesh K. Gelda; Emmet M. Owens; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 186 - 196 | Calibration, Verification, and an Application of a Two-Dimensional Hydrothermal Model [CE-QUAL-W2(t)] for Cannonsville Reservoir | The successful testing of a two-dimensional hydrothermal/hydrodynamic model, CE-QUAL-W2(t), for Cannonsville Reservoir is documented. The model is calibrated to the detailed temperature data collected in the reservoir (depth-profiles at six locations) over the April-November interval (weekly) of 1995, using comprehensive hydrologic and on-site meteorological forcing data. Further, the frequency of current oscillations predicted for the lower layers matched results of independent determinations made from thermistor chain deployments (two locations). The model is verified through the successful continuous simulation of the observed thermal stratification regime of the reservoir for the 1988-1994 interval, a period in which wide interannual differences were observed related to variations in meteorology and operations. The model performs well in simulating: 1) the timing of stratification and turnover, 2) the duration of stratification, 3) the dimensions of the epilimnion and hypolimnion, 4) the temperature of the layers, and 5) longitudinal variations in these features. The tested model is applied to characterize longitudinal transport of a conservative substance input at the mouth of the principal tributary as a pulse event (e.g., spill). |
| Spatial and Temporal Patterns of THM Precursors in a Eutrophic Reservoir | Carol Stepczuk; Angela B. Martin; Steven W. Effler; Jay A. Bloomfield; Martin T. Auer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 356 - 366 | Spatial and Temporal Patterns of THM Precursors in a Eutrophic Reservoir | Temporal and spatial patterns of trihalomethane (THM) precursors (measured as THM formation potential, THMFP) are described and analyzed for eutrophic Cannonsville Reservoir, NY, based on monitoring conducted weekly over the April to November interval of 1995 at three sites along the main axis of the reservoir. Ninety-eight percent of the precursors formed chloroform, and 94% were in a dissolved (0.45-μm filtrate) form. Distinct seasonal, vertical and longitudinal patterns were observed. Progressive increases in THMFP occurred from spring (~170 μg · L-1) through midsummer (~360 μg·L-1) in the epilimnion of the lacustrine zone of die reservoir, followed by subsequent decreases through early fell. Progressive, but smaller, increases in THMFP occurred in the hypolimnion throughout the period of stratification. Vertical patterns in dissolved THMFP within the hypolimnion indicate the sediments were not an important source of precursors to the water column. Summer epilimnetic concentrations of THMFP were substantially higher than those reported for the inflows (Stepczuk et al. 1998a), establishing the operation of autochtonous sources. Features of the THMFP patterns, including epilimnetic enrichment, the seasonality, and higher concentrations in the more eutrophic riverine zone, and the results of a single laboratory experiment, indicate a linkage between primary production and autochthonous production of precursors. Dissolved organic carbon was not a good surrogate measure of THMFP. |
| Identification and Analysis of Hydrodynamic and Transport Characteristics of Cannonsville Reservoir | E. M. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 162 - 171 | Identification and Analysis of Hydrodynamic and Transport Characteristics of Cannonsville Reservoir | A monitoring program consisting of regular observations of temperature and conductivity in the tributaries to and water column of Cannonsville Reservoir from April through November of 1995 is described. The results are analyzed in order to identify and quantify transport processes that affect the distribution of heat and mass constituents. The low temperature of the major reservoir tributary relative to reservoir surface waters in late summer and fall is observed to cause a plunging inflow or negatively-buoyant density current in the reservoir, although evidence is provided that the plunging inflow is not the cause of the observed metalimnetic oxygen minima. A seasonal increase in the specific conductivity of the major tributary in summer creates a longitudinal gradient in conductivity in the epilimnion of the reservoir. A simple analytical model is used to estimate the longitudinal dispersion coefficient in the epilimnion over the summer based on this conductivity gradient. High-frequency observations of temperature using thermistor chains deployed late in the summer stratification period indicate the presence of internal waves in the stratified layers of the reservoir. Current measurements indicate the occurrence of episodes of current speed of a magnitude sufficient to cause sediment resuspension. The application of hydrothermal models to the reservoir to support water quality management is discussed. |
| Development and Testing of a Nutrient-Phytoplankto Model for Cannonsville Reservoir | S. M. Doerr; E. M. Owens; R. K. Gelda; M. T. Auer; S. W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 301 - 321 | Development and Testing of a Nutrient-Phytoplankto Model for Cannonsville Reservoir | A dynamic multi-layer one-dimensional mass balance nutrient-phytoplankton (eutrophication) model is developed and tested for the lacustrine zone of eutrophic Cannonsville Reservoir. The model simulates concentrations of chlorophyll (Chl), zooplankton biomass, various forms of phosphorus (P) and nitrogen (N), and dissolved oxygen (DO). Model development was integrated with, and supported by, limnological analysis of detailed monitoring data and findings of various system-specific process/kinetic studies. Model testing is supported by comprehensive monitoring data of in-reservoir concentrations and important environmental and operational forcing conditions. Model credibility is enhanced by the independent determination of a number of important model coefficients from the process/kinetic studies, which greatly constrains the role of calibration. The model performed well in simulating observations of seasonal average Chl concentration, the progressive depletions of nitrate plus nitrite from the epilimnion and DO from the hypolimnion, and the low and relatively uniform epilimnetic concentrations of other dissolved forms of N and P, and is thus an appropriate management tool to evaluate scenarios aimed at abating the reservoir's eutrophication problems. |
| A Modeling Analysis of THM Precursors for a Eutrophic Reservoir | Carol Stepczuk; Emmet M. Owens; Steven W. Effler; Martin T. Auer; Jay A. Bloomfield | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 367 - 378 | A Modeling Analysis of THM Precursors for a Eutrophic Reservoir | Mass balance modeling analyses were conducted for trihalomethane (THM) precursors in eutrophic Cannonsville Reservoir to resolve the contributions of allochthonous and autochthonous inputs to the reservoir's precursor pool, and to move toward a predictive tool that would support related managementactions. The analyses focus on the April-November interval of 1995, and are supported by detailed external loading (Stepczuk et al. 1998a) and reservoir water column (Stepczuk et al. 1998b) data for precursors. Net autochthonous production of precursors in the epilimnion, apparently driven by primary productivity, was a major source of precursors for the reservoir, representing about two-thirds of the cumulative mass input over the April-mid-summer interval. An undefined loss process(es) operated simultaneously during the study period. Major differences in behavior of the dissolved organic carbon (DOC) and THM precursor pools of the reservoir, depicted by the modeling analysis, are not supportive of the use of DOC as a surrogate estimator of precursor concentration. A preliminary mechanistic precursor model, developed by adding a primary production-based source term and a first order loss/decay term to a eutrophication model for the reservoir (Doerr et al. 1998), performed reasonably well in matching the precursor patterns observed for the lacustrine zone of the reservoir in 1995. An analysis conducted with this model indicates the need to resolve differences in the lability of allochthonous and autochthonous inputs within the model framework. |
| The Optical Water Quality of Cannonsville Reservoir: Spatial and Temporal Patterns, and the Relative Roles of Phytoplankton and Inorganic Tripton | S. W. Effler; M. G. Perkins; D. L. Johnson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 238 - 253 | The Optical Water Quality of Cannonsville Reservoir: Spatial and Temporal Patterns, and the Relative Roles of Phytoplankton and Inorganic Tripton | Longitudinal and temporal distributions of optical properties, and the relative role of selected light attenuating constituents in regulating light penetration, in Cannonsville Reservoir, NY, in 1995 are documented. The analysis is supported by field measurements of light penetration; die angular distribution of irradiance (reflectance); and the spectral quality of penetrating light; laboratory measurements of turbidity, chlorophyll, gelbstoff, and microscopy-based individual particle size and elemental chemistry, and calculations of absorption and scattering coefficients and their components. Longitudinal gradients in attenuating components, and therefore optical properties, prevailed along the main axis of the reservoir; light attenuation and the relative role of scattering decreased with the approach to the dam. Large temporal variations in optical characteristics occurred. These dynamics were mostly controlled by variations in phytoplankton biomass in spring and early summer, when the reservoir was full, but resuspended inorganic tripton (non-phytoplankton particles; suspensoids) became the regulating component as the reservoir was drawn down. Quantitative optical frameworks (models) are applied to simulate light penetration conditions that would have prevailed for scenarios of reductions in phytoplankton biomass and/or inorganic tripton. |
| Turbidity and Particle Signatures Imparted by Runoff Events in Ashokan Reservoir, NY | S. W. Effler; M. G. Perkins; N. Ohrazda; C. M. Brooks; B. A. Wagner; D. L. Johnson; F. Peng; A. Bennett | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 254 - 265 | Turbidity and Particle Signatures Imparted by Runoff Events in Ashokan Reservoir, NY | The occurrence, temporal and spatial patterns, and origins of turbidity events, and their linkage to runoff events, are documented for a water supply impoundment with two separated basins, Ashokan Reservoir, NY. The analysis is supported by a comprehensive 6-week study of the major inflow and the reservoir during the summer of 1996, that captured the effects of a single runoff event, and turbidity (Tn) measurements made in the reservoir and the water supply intakes for the entire year. Measurements supporting the short-term study include: temperature, specific conductance, beam attenuation coefficient, electronic particle counts, Secchi disc transparency, Tn, up- and downwelling cosine irradiance, chlorophyll, microscopy-based individual particle size and chemistry, and total suspended solids (TSS) on sediment trap collections. The external load of mostly quartz and clay particles delivered by die principal tributary, as an interflow, during the summer runoff event imparted distinct signatures in Tn and deposition within the epilimnion of the receiving basin; the other basin remained unaffected by comparison. The deposition rate of TSS and Tn increased in the receiving basin in response to die runoff-based loading; decreasing gradients in both parameters were observed within this basin downstream of the entry point of die tributary. More than 85% of Tn in die receiving basin during die 6-week study is attributed to inorganic tripton particles of terrigenous origins. Analysis of the longer-term data indicates elevated Tn values (maximum of 150 NTU) occur routinely in die receiving basin following runoff events, and diat diis effect extends to die other basin, including the water supply intake(s), during intervals other than summer stratification. |
| Sources and Fate of Giardia Cysts and Cryptosporidium Oocysts in Surface Waters | Susan T. Bagley; Martin T. Auer; David A. Stern; Mary J. Babiera | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 2 | 1998 | 379 - 392 | Sources and Fate of Giardia Cysts and Cryptosporidium Oocysts in Surface Waters | A literature review was conducted to evaluate the mechanisms mediating the fate of Giardia lamblia cysts and Cryptosporidium sp. oocysts in surface waters, particularly in lakes and reservoirs. Emphasis was placed on quantification of source and sink terms as applied in mass balance models. The literature review results indicated that cysts and oocysts [referred to collectively as (oo) cysts] are commonly detected over a wide range of concentrations in a wide variety of aquatic systems. Humans and other animals are considered to be the sources of (oo)cysts introduced to aquatic systems. Most studies included some measure of (oo) cyst viability but not necessarily infectivity. Sedimentation was identified as an important loss mechanism for (oo) cysts in lakes and reservoirs. There were general indications that ambient irradiation or pH levels would have little effect on (oo) cyst viability or infectivity, while temperature, drying, and redox levels may have more varying effects. The (oo) cysts would be expected to remain viable for longer periods than for fecal bacteria in similar circumstances. Kinetic submodels (as associated coefficients) required to quantify these phenomena are generally unavailable. |
| Influence of Sediment and Phosphorus Loading on Phytoplankton Communities in an Urban Piedmont Reservoir | J. M. Burkholder; L. M. Larsen; H. B. Glasgow Jr.; K. M. Mason; P. Gama; J. E. Parsons | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 110 - 121 | Influence of Sediment and Phosphorus Loading on Phytoplankton Communities in an Urban Piedmont Reservoir | The response of phytoplankton communities to an imposed gradient of sediment loading under low versus high phosphate enrichment was assessed with enclosures (2-m-diameter polyethylene columns, open to the surface and the sediment) in a small piedmont reservoir within an urbanized watershed. The experimental design included replicated controls [CON, with ambient suspended solids (SS) and phosphorus (P)] and treatments low clay (LC), a natural hydrated sediment mix, sufficient clay initially added to effect an average daily concentration of 5 mg SS L-1 d-1), high clay (HC), 15 mg SS·L-1·d-1, phosphate enrichment (PHOS), ≥ 250 μg PO4-3 P L-1); LC+P, and HC+P, imposed for ca. 10 weeks in the summer growing season. Clay additions without P led to decreased phytoplankton production (as chlorophyll a, chla) relative to controls, with colonial blue-greens and colonial greens increasing in LC, and HC dominated by filamentous blue-greens and mixotrophic flagellates. Significant increases in chla occurred in the epilimnion and hypolimnion of the P treatment, and in the epilimnion of LC+P, and HC+P. Low variability in community response occurred in treatments with sediment loading alone, whereas the P additions imposed high variability among replicates within treatments considering both total algal production and the timing of blooms. Overall, P enrichment stimulated nuisance algal blooms whether alone or with low sediment inputs, and increased P mitigated the adverse effects of high sediment loading in supporting blue-green (cyanobacteria) blooms. Undesirable algae such as Anabaena flos-aquae and A. circinalis were able to maintain populations under high sediment loading, and may serve as an innoculum for development of noxious blooms when shallow, turbid systems experienced high P enrichment. |
| Effects of Aggregation on Chlorophyll-Phosphorus Relations in Missouri Reservoirs | John R. Jones; Matthew F. Knowlton; Mark S. Kaiser | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 1-9 | Effects of Aggregation on Chlorophyll-Phosphorus Relations in Missouri Reservoirs | Using chlorophyll and phosphorus data from 119 Missouri reservoirs we show how data aggregation-averaging data into seasonal means or long-term lake means - influences our ability to make inferences from large-scale statistical regression analyses. We demonstrate the most obvious phenomenon of data aggregation, that relations between variables estimated from aggregated data are generally stronger than the same relations estimated from unaggregated data. Averaging reduces the often large variation in the response of chlorophyll to phosphorus (Chl-TP) that characterizes measurements of these variables in lakes. We also demonstrate that inferences made from statistical regression analyses apply only to situations that match the level of aggregation used to produce the model. Using lake means we found a strong positive Chl-TP relation. This strong cross-sectional pattern among lakes in the study, however, did not always reflect the relation of these variables to one another in individual lakes. And the cross-sectional pattern has limited value in predicting conditions in unaggregated data. The effect of aggregation on the estimated strength of a regression relation serves as a caution in transferring inferential statements about the effect of TP on Chi between temporal scales and among lakes. |
| Como Lake, Minnesota: The Long-Term Response of a Shallow Urban Lake to Biomanipulation | T. A. Noonan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 92 - 109 | Como Lake, Minnesota: The Long-Term Response of a Shallow Urban Lake to Biomanipulation | Como Lake, a shallow hypereutrophic 29-ha lake, located in St. Paul, MN, was biomanipulated by fisheries renovation using rotenone in September 1985, to reduce algal standing crop, improve aesthetics, and increase recreational use. Long-term monitoring (1982-97) indicates a cyclic water quality and biologic response following the initial biomanipulation. Algal standing crop, as measured by chlorophyll a (CHLA), varied positively with total phosphorus (TP) and total nitrogen (TN) for the post-biomanipulation years (1986-97), with marked changes in phytoplankton community composition and population abundance. Nutrient-phytoplankton (“bottom-upâ€) interactions are a strong and consistent force in Como Lake following biomanipulation due to continued high normalized areal phosphorus loading (~735 mg m-2 yr-1). “Top-down†influences have not yet stabilized, but appear to have dampened with time due to decreased effectiveness of sportfishing regulations and fish stocking, along with partial winterkill due to aerator failure, to maintain piscivore abundance. Planktivorous fish abundance and size-selective feeding pressure on large-bodied herbivorous zooplankton grazers, as well as Daphnia biomass, have fluctuated cyclically over the study period. Recent decreased macrophyte abundance suggests a return to phytoplankton dominance as the long-term stable state for Como Lake. Monitoring results suggest that future management efforts in Como Lake should include renewed emphasis on fisheries and watershed management to promote the presence of macrophyte growth and a reduction in the magnitude of “bottom-up†forces, particularly nutrients, that effect the size of the algal population. |
| Assessment of Historical Eau Pleine Reservoir Operations, Winter Dissolved Oxygen, and Periodic Fishkills: Strategies for Future Reservoir Management | David M. Coon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 77 - 85 | Assessment of Historical Eau Pleine Reservoir Operations, Winter Dissolved Oxygen, and Periodic Fishkills: Strategies for Future Reservoir Management | The Eau Pleine Reservoir has historically experienced point and non-point source (NPS) pollution resulting in winter anoxic conditions and periodic fishkills. Because the reservoir has the potential to support a quality sport fishery, including walleye (Stizostedion vitreum) and northern pike (Esox lucius), minimizing the incidence of anoxic winter conditions is a management goal. During winter reservoir drawdown, a dissolved oxygen (DO) sag typically develops in the headwater and moves through the reservoir, leading to periodic fishkills. To identify factors that influence the DO sag and to determine if those factors could be managed, I evaluated historical fishkill records, winter DO data, river base flow (inflow), precipitation/runoff events, and reservoir operations data collected over a 24-year period. A combination of three key factors consistently affected the character (magnitude and duration) of the DO sag and the incidence of fishkills. No fishkills occurred when 1) reservoir volume at the start of winter drawdown was greater than 60%; 2) river base flow was 6 cfs or greater; and 3) the DO sag did not develop until after February 1.1 postulated that anoxic conditions during winter could be minimized by using these factors as guidelines for future reservoir operation, along with continued use of two aeration systems. Reservoir operating guidelines were developed and have been followed since 1993; no fishkills have occurred. |
| Effects of a Large Kansas Reservoir on Downstream Groundwater Quality | Donald G. Huggins; Gregory L. Howick | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 86 - 91 | Effects of a Large Kansas Reservoir on Downstream Groundwater Quality | Several water quality parameters, including inorganic nitrogens and phosphorus, were measured in groundwater from the Republican River aquifer above and below Milford Reservoir, Kansas. Ammonia and total phosphorus concentrations were considerably higher (>50%) in groundwater from the pressure relief wells along the toe of Milford Reservoir dam than from well water sampled upstream of the lake. However, the concentration of these compounds decreased to near upstream levels within 1.2 km downstream of the dam. Within the array of pressure relief wells, the concentration of ammonia was greatest in water from wells near the center of the dam. Conductivity, hardness, and alkalinity were lower, and pH was higher, in groundwater below Milford Reservoir than above it. The ratio of ammonia to total inorganic nitrogen in elutriates from Milford Reservoir sediments and water from the pressure relief wells was similar. These results suggest that water seeping out of reservoirs into underlying alluvial aquifers can leach soluble compounds, which exist in reservoir sediments, into the groundwater. |
| Successful Water Quality Monitoring: The Right Combination of Intent, Measurement, Interpretation, and a Cooperating Ecosystem | David M. Søballe | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 10-20 | Successful Water Quality Monitoring: The Right Combination of Intent, Measurement, Interpretation, and a Cooperating Ecosystem | Water quality monitoring is invaluable to ensure compliance with regulations, detect trends or patterns, and advance ecological understanding. However, monitoring typically measures only a few characteristics in a small fraction of a large and complex system, and thus the information contained in monitoring data depends upon which features of the ecosystem are actually captured by the measurements. Difficulties arise when these data contain something other than intended, but this can be minimized if the purpose of the sampling is clear, and the sampling design, measurements, and data interpretations are all compatible with this purpose. The monitoring program and data interpretation must also be properly matched to the structure and functioning of the system. Obtaining this match is sometimes an iterative process that demands a close link between research and monitoring. This paper focuses on water quality monitoring that is intended to track trends in aquatic resources and advance ecological understanding. It includes examples from three monitoring programs and a simulation exercise that illustrate problems that arise when the information content of monitoring data differs from expectation. The examples show (1) how inconsistencies among, or lack of information about, the basic elements of a monitoring program (intent, design, measurement, interpretation, and the monitored system) can produce a systematic difference (bias) between monitoring measurements and sampling intent or interpretation, and (2) that bias is not just a statistical consideration, but an insidious problem that can undermine the scientific integrity of a monitoring program. Some general suggestions are provided and hopefully these examples will help those engaged in water quality monitoring to enhance and protect the value of their monitoring investment. |
| Potential Effects of Canada Geese and Climate Change on Phosphorus Inputs to Suburban Lakes of the Northeastern U.S.A. | Marianne V. Moore; Pavla Zakova; Kristin A. Shaeffer; Rebecca P. Burton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 52 - 59 | Potential Effects of Canada Geese and Climate Change on Phosphorus Inputs to Suburban Lakes of the Northeastern U.S.A. | Inputs of total phosphorus (TP) to a small lake (0.4 km2) located in western suburban Boston were compared during a drought (fall 1995) and a normal rainfall period (fall 1994) to explore potential effects of Canada geese (Branta canadensis maxima) and climate change on phosphorus loading to suburban lakes of the Northeastern U.S.A. In fall 1994, the watershed supplied 18 times more TP than Canada geese, but during the fall drought of 1995, TP from Canada geese exceeded that from the watershed by more than 7 times. Differences in the relative importance of TP loading from Canada geese and the watershed were caused by variation in streamflow between years. Under conditions of climatic warming, annual streamflow in the Northeast (U.S.A.) is projected to decline by ~30% with greatest reductions (~60%) occurring in the fall. At this time of year, Canada geese are most abundant and are likely to become the major contributor of TP to urban lakes. Furthermore, annual absolute inputs of TP from geese to suburban and urban lakes of the Northeast are likely to increase with warmer conditions associated with climate change, because ice cover in winter is unlikely to form on lakes in this region. Consequently, geese are likely to remain on such lakes during the winter rather than moving to open coastal waters as they do presently when lakes freeze. Thus, both the warmer and drier conditions predicted to accompany climate change may exacerbate effects of Canada geese on the water quality of suburban-urban lakes in this region of North America. |
| Seasonal Patterns of Chlorophyll, Nutrient Concentrations and Secchi Disk Transparency in Florida Lakes | Claude D. Brown; Daniel E. Canfield Jr.; Roger W. Bachmann; Mark V. Hoyer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 60 - 76 | Seasonal Patterns of Chlorophyll, Nutrient Concentrations and Secchi Disk Transparency in Florida Lakes | Florida lakes as a group exhibited a distinct seasonal pattern in the concentration of algal chlorophylls. This conclusion was based on an analysis of data from the Florida LAKEWATCH 1994 database containing 416 lake-years of observations from 209 lakes. For oligotrophic, mesotrophic, and eutrophic lakes, monthly chlorophyll concentrations were typically lower than the annual mean chlorophyll concentration from December to May and were higher from August to October. Hypereutrophic lakes (annual mean chlorophyll > 40 μg·L-1) tend to have high fluctuating levels of algal chlorophyll for most of the year except for low levels in December, January, and February. Maximum chlorophyll concentrations tended to occur most frequently from August to October, however the maximum or minimum level in any given lake can occur at any time of the year. The variance (s2) in monthly chlorophyll concentrations over the course of a year increased with increasing annual mean chlorophyll for Florida lakes. There was also seasonal variation in the monthly values for total phosphorus, total nitrogen, and Secchi disk transparency though the magnitude of the fluctuations was about half that for chlorophyll. They also showed increasing variance with increasing lake means. The 95% confidence limits for estimates of annual mean chlorophyll concentrations in these lakes with 12 monthly samples was ±27% of the mean. Similar confidence limits for means of total phosphorus, total nitrogen, and Secchi disk transparency were 15%, 9%, and 10%, respectively. |
| Distribution of Cladoceran Zooplankton Among Prairie Pothole Wetlands in Northwest Iowa | Evelyn E. Gaiser; Kenneth L. Lang | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 37 - 51 | Distribution of Cladoceran Zooplankton Among Prairie Pothole Wetlands in Northwest Iowa | Cladoceran zooplankton were collected and identified from spring and summer samples from vegetated and open water areas of 26 remnant glacial lakes in Dickinson County, Iowa. The purpose of the study was to determine the factors influencing the structure and composition of zooplankton assemblages as a tool for aiding environmental management of the region's prairie pothole wetlands and ponds. The ponds were assorted into five categories based on morphometric features and productivity: 'chain lakes' defined large, deep, interconnected lakes; 'algal potholes' were small pothole wetlands dominated by algal primary producers; 'weedy potholes' denoted similar ponds dominated by macrophytic vegetation; 'sloughs' were similarly dominated by macrophytes, but found along intermittent waterways subject to drying; and 'walleye ponds' were kettle-hole ponds modified for the production of gamefish. Multivariate analyses and similarity indices were used to determine the relationship between cladoceran assemblages and the five major lake types. Each lake type contained a distinct cladoceran assemblage that was influenced by the abundance of macrophytes and probably also by fish, although fish species composition was not directly measured. Cladoceran diversity also increased with increased predominance of macrophytes among lakes, and within the same lake in different seasons and sampling locations. A model was built to describe the relationship between cladoceran assemblages and macrophytes that could be used in management or paleoecological applications. If prairie potholes are to be managed for high invertebrate diversity to support waterfowl, our results promote plans that diversify benthic structure within ponds. Advanced eutrophication and conversion of existing potholes to game fish rearing ponds severely limit the abundance and composition of microcrustaceans, which is likely to alter upper levels of the food web. |
| Evaluation of Data Generated from Lake Samples Collected by Volunteers | Daniel V. Obrecht; Margaret Milanick; Bruce D. Perkins; Diana Ready; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 21 - 27 | Evaluation of Data Generated from Lake Samples Collected by Volunteers | The goals of the Lakes of Missouri Volunteer Program are to involve citizens in the collection of water samples to monitor lake trophic state and to provide outreach education about lake water quality. Results indicate data generated with volunteer help are of the same quality as that generated by a research laboratory. This conclusion is based on three different methods of evaluation: (1) Comparisons of volunteer and University collected samples showed trophic state classifications were the same for 74% of lakes based on total phosphorus, 84% for total nitrogen and 89% for chlorophyll; (2) Agreement between paired chlorophyll filters was assessed to gauge volunteer processing technique; 88% of the filter pairs was considered good or excellent based on a rating scale developed for this program; (3) Split sampling showed no significant differences for total suspended solids, chlorophyll or total nitrogen. Total phosphorus analysis showed a significant difference with volunteer samples being consistently less than University samples. Prior to analysis, volunteer samples for total phosphorus were stored frozen in high density polyethylene bottles while University samples were refrigerated in glass tubes. This difference in storage method may have caused the irregularity in our results. |
| Comparisons of Phytoplankton and Epilithic Algae of Selby Lake – Gates of the Arctic National Park and Preserve, Alaska | Jacqueline D. LaPerriere; John R. Jones; Bryn H. Tracy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 14 | 1 | 1998 | 28 - 36 | Comparisons of Phytoplankton and Epilithic Algae of Selby Lake - Gates of the Arctic National Park and Preserve, Alaska | Selby Lake in Gates of the Arctic National Park and Preserve was assessed as oligotrophic due to measurements of low nutrient concentrations and resultant low planktonic biomass as total chlorophyll. An orthograde oxygen profile in early summer also indicated an oligotrophic condition. Total nitrogen averaged about 0.4 μg·L-1 and total phosphorus about 4 μg·L-1, resulting in a TN:TP ratio of about 100, which indicated the planktonic algae were probably limited by phosphorus. Nutrient stimulation bioassays confirmed this. Nitrogen alone was not stimulating to plankton algal growth, but nitrogen and phosphorus added together in the bioassays stimulated growth more than just phosphorus, as is often found in oligotrophic lakes. Aerial observation of Selby Lake and similar nearby lakes had indicated that epilithic benthic algal biomass was probably relatively high because the extensive shallows were visibly green. When recent growth in the ice-scour zone (< 2 m) was sampled in early July, the whole lake average standing crop of epilithic algae was estimated as approximately equal to the whole lake standing crop of phytoplankton. Biomass was greater near inlets than away from inlets. Epilithic algal biomass varied inversely with the temperature of inlets and directly with the inlets' total nitrogen concentration. Root zone fixation of atmospheric nitrogen by alders may be the source of N in the enriched inlets, and cold inlets probably plunge to the lake bottom, bathing the epilithicalgae with nutrients. The importance of benthicalgae in clear-oligotrophic lakes with extensive shallows need to be recognized. |
| Experiences Using Sonar® A.S. Aquatic Herbicide in Michigan | Craig S. Smith; G. Douglas Pullman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 4 | 1997 | 338 - 346 | Experiences Using Sonar® A.S. Aquatic Herbicide in Michigan | Field vegetation surveys were used to evaluate some of the target and nontarget impacts associated with whole-lake applications of Sonar®*1 A.S. aquatic herbicide (active ingredient, fluridone) applied to Michigan lakes between 1990 and 1996. The applications analyzed were made in the spring to control Eurasian watermilfoil (Myriophyllum spicatum L.) and/ or curly leaf pondweed (Potamogeton crispus L.). Dose-rate response curves for the control of individual aquatic plant species were constructed from plant species lists compiled before and after treatment. Plant species varied considerably in their response to Sonar. Eurasian watermilf oil, curly leaf pondweed, elodea (Ehdea canadensis Michaux.), naiads (Najas sp.), and coontail (Ceratophyllum demersum L.) were highly susceptible; bladderwort (Utricularia sp.) and water stargrass (Heteranthera dubia (Jacq.) MacM.) were very tolerant; and large-leaf pondweeds (Potamogeton sp.), wild celery (Vallisneria americana Michaux.), narrow-leaf pondweeds (Potamogeton sp.), medium-leaf pondweeds (Potamogeton sp.), and flatstem pondweed (Potamogeton zosteriformis Fern.) exhibited intermediate susceptibility. Sonar A.S. impacts on plant cover and diversity were highly dose dependent. Both cover and diversity usually declined during the year of treatment following applications at dose rates above 10 ppb (calculated on the volume of the top 10-ft layer of the lake). Cover and diversity typically recovered within 1 to 3 years following applications at these rates. Applications at dose rates of 10 ppb or less were typically much more selective. Impacts of low-dose rate treatments on total and native plant cover depended on the abundance of highly sensitive plant species, including Eurasian watermilfoil, curly leaf pondweed, elodea, coontail, naiad, and native watermilfoil. Where these species constituted a small part of the community, total native plant cover often increased following treatment. Low-dose rate (<10 ppb) Sonar applications are an effective method for controlling Eurasian watermilfoil and curly leaf pondweed with minimal impact on many native plant species. |
| A Test Of A Morphometric Index To Predict Vertical Phosphorus Transport in Lakes | Laura K. Mataraza; G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 4 | 1997 | 328 - 337 | A Test Of A Morphometric Index To Predict Vertical Phosphorus Transport in Lakes | Osgood (1988) proposed a morphometric index, mean depth over square root of surface area ( / √ A0), to estimate the probability of partial or complete mixing of lakes during summer storms. Such mixing could introduce phosphorus (P)-rich waters to the entire water column (polymictic lakes) or to the epilimnion, and could delay lake recovery following abatement of allochthonous P loading. Cooke et al. (1993) hypothesized that aluminum sulfate (alum) applications to control internal P loading would be most effective in lakes with an Osgood Index less than 6 and significant diversion of external loading. We tested the hypothesis that vertical P transport is higher in lakes with the lowest Osgood Index numbers by estimating transport in four northeastern Ohio lakes with Osgood numbers of 2.9, 7.4, 9.7, and 26.3 during Summer 1992. The hypothesis was rejected. Although the lake with the lowest number most often had the highest vertical P transport rate, transport was not significantly different between lakes. The qualitative trends among lakes corresponded with their relative differences in P concentration gradients. Lakes with a high Osgood Index could have significant vertical P transport if there is a steep P gradient in the water column. The results suggest that alum applications have the potential to decrease trophic state in lakes with a high Osgood Index value. |
| An Evaluation of Trace Element Accumulation in Aquatic Macrophytes of the Novosibirsk Reservoir | Laura M. Kipriyanova | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 4 | 1997 | 315 - 327 | An Evaluation of Trace Element Accumulation in Aquatic Macrophytes of the Novosibirsk Reservoir | Concentrations of 12 trace elements (Hg, Cd, Be, Co, As, V, Pb, Cu, Ni, Zn, Ba, Mn) were determined for different organs of 6 dominant macrophytes of the Novosibirsk Reservoir (Phragmites australis (Cav.) Trin. ex Steud., Typha angustifolia L., Nymphoides peltata (S.G. Gmel) O. Kuntze, Potamogeton lucens L., Potamogeton perfoliatus L., Salvinia natans (L.) All.). This investigation showed: 1) concentrations of trace elements (excepting Mn) in roots and rootstocks were greater than in organs above the sediment surface, 2) maximum trace element concentrations were observed in Salvinia natansr, Nymphoides peltata and Potamogeton species accumulated lesser amounts than Salvinia natans; Phragmites australis and Typha angustifolia always showed the lowest concentrations of all elements in both above- and underground organs, and 3) because of their greater biomass, communities of Phragmites australis accounted for greater total amounts of trace elements than other macrophyte communities of Novosibirsk Reservoir. These communities contained 57% of Cd, 52% of As, 42% of Pb, 54% of Cu, 57% of Ni, 66% of Zn, 32% of Mn accumulated in the six studied macrophyte communities of Novosibirsk Reservoir. |
| Pine Lake Response to Diversion of Wetland Inflow | Jean M. Jacoby; Chauncey W. Anderson; Eugene B. Welch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 4 | 1997 | 302 - 314 | Pine Lake Response to Diversion of Wetland Inflow | The drainage from a wetland was diverted in fall 1988 from eutrophic Pine Lake, a small (36-ha), thermally stratified (maximum depth 11.9 m) lake in the Puget Sound region. Although the wetland contributed only 20% of the lake's annual phosphorus loading, 90% of the phosphorus was soluble and entered the lake's lighted zone during winter-spring. Furthermore, the wetland drainage fueled a spring blue-green algal bloom, which was the lake's principal water quality problem. The diversion resulted in a reduction of 36-kg TP loading (86% of total external) and greatly improved lake water quality during spring. The spring blue-greenal gal bloom was eliminated in 1989 and 1990. Spring epilimnetic mean TP declined from 27 μg· L-1 in 1980 to 16 μg · L-J in 1990 and mean chl a decreased from 18 to 6 μg· L-1, while transparency increased from 1.9 to 4.5 m. However, lake quality during late summer and fall worsened from 1980 to 1990 concomitant with a doubling in hypolimnetic TP. Metalimnetic populations of blue-green algae (Aphanizomenon and Anabaena) formed surface scums following lake turnover in the late summer and fall of 1989 and 1990. Increasing development in the watershed (from 9% to >50% residential since 1976) probably contributed increased P loading to the lake and possibly increased hypolimnetic P and fall algal blooms. |
| A Critical Evaluation of Phosphorus Management Goals for Lake Okeechobee, Florida, USA | Karl E. Havens; R. Thomas James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 4 | 1997 | 292 - 301 | A Critical Evaluation of Phosphorus Management Goals for Lake Okeechobee, Florida, USA | An empirical phosphorus (P) loading model modified from the original Vollenweider formulation has been used since the late 1970s to track progress toward a legally mandated P loading target for Lake Okeechobee, Florida. The loading target is designed to achieve, as an annual average for the pelagic region, a total P (TP) concentration of 40 μg L-1. This TP goal is not based on historic data from the lake, nor on how certain levels of TP might cause use-impairment or ecological harm. Nevertheless, our retrospective analyses indicate that the goal falls within a range of TP concentrations (26 to 92 μg L-1) derived from historical data, pelagic TP-algal bloom relationships, pelagic TP-chlorophyll a relationships, and a Florida lake regression model. When first applied to Lake Okeechobee, the modified Vollenweider model gave accurate estimates of pelagic TP, but now it under-predicts TP by nearly 50 percent. This may reflect time lags in lake responses to recent reductions in P loads, an increase in the relative magnitude of internal vs. external P loads, or a change of in-lake processing of P. The lake's P budget shows a decline over time in the net sedimentation of P. The Vollenweider model estimates P sedimentation based on a fixed empirical relationship using water residence time (τw), a parameter that has not displayed a significant historical trend. Given these issues, it is important to consider whether the existing model is an effective management tool for Lake Okeechobee. Our results indicate that the modified Vollenweider model may suffice as a coarse-scale tool for tracking progress in the eutrophication management program, with a major caveat: model predictions of pelagic TP at any given external loading rate may reflect what is potentially attainable, if internal loading rates decrease to their previous lower levels. A more complex dynamic model is being developed, which accounts for sediment-water P exchanges. The new model should provide more accurate estimates of pelagic TP, as well as estimates of recovery time and predictions of short-term responses to management actions. |
| Toxics Zoning for Reservoir Source Water Protection | Jonathan B. Butcher | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 4 | 1997 | 281 - 291 | Toxics Zoning for Reservoir Source Water Protection | Water supply reservoirs in urban areas need protection from potential loading of toxic chemicals associated with industrial and commercial land uses, as well as transportation spills. As it is infeasible to eliminate all uses of toxic chemicals from developed watersheds, management strategies attempt to eliminate potential sources from the most sensitive areas. In many jurisdictions this goal is implemented through zoning restrictions which prohibit commercial/industrial activities within a certain fixed distance of the reservoir pool. This simple approach, however, often imposes unnecessary restrictions on some landowners, while failing to provide uniform protection to the water supply. Land use restrictions are never popular, and should be targeted toward the most sensitive potential source areas. A quantitative, geographic assessment of relative risk from all points within the watershed can be used to maximize protection from zoning while minimizing restrictions on economic growth. A steady-state modeling approach, as presented here, provides a rational basis for developing zoning restrictions for source water protection. |
| Relationship of Seasonal Water Quality to Chlorophyll a Concentration in Lake Manatee, Florida | R. A. Clarke; C. D. Stanley; B. W. MacLeod; B. L. McNeal | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 253 - 258 | Relationship of Seasonal Water Quality to Chlorophyll a Concentration in Lake Manatee, Florida | Algal growth causing taste and odor problems in surface drinking water supplies can be costly to treat. A study was conducted to determine the relationship of lake water quality to algal growth in Lake Manatee, Florida, a nitrogen (N)-limited water body. Chlorophyll a (chl a) concentration was used as the indicator of algal density. A number of water quality parameters measured from monthly water samples collected during 1990-1992 were evaluated to determine whether a relationship with algal density existed. Using sensitivity analyses to determine which parameters were most influential, a prediction equation was developed using water temperature, nitrate concentration, nitrite concentration, total N/total phosphorus (P) ratio, and electrical conductivity as the most important independent variables. Existing equations used to predict Chl a concentration, developed from previous research, were also tested for applicability in Lake Manatee's situation (using independent data collected in 1993) and were found to be inadequate. The equation developed from this study (p < 0.01, r2 = 0.41) was verified using the same independent data collected in 1993. We conclude that algal density changes resulting in blooms which cause water quality degradation may be predicted based on timely sampling and analysis of key water quality parameters. |
| Establishment of Native Aquatic Plants for Fish Habitat: Test Plantings in Two North Texas Reservoirs | Robert D. Doyle; R. Michael Smart; Clell Guest; Ken Bickel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 259 - 269 | Establishment of Native Aquatic Plants for Fish Habitat: Test Plantings in Two North Texas Reservoirs | Test plantings of native aquatic plant species were made in two Texas reservoirs. Founder populations of three native submersed or floating-leaved species were established within small (2- 2-m) exclosures utilizing actively growing transplants. Herbivory and excessive sedimentation proved to be deterrents to plant survival and expansion. Nine small founder populations of Vallisneria americana were established within North Lake, a small reservoir with limited water level fluctuations and a developing community of native pioneer aquatic plants. Plants within all nine exclosures successfully established and began vegetative growth. In intact exclosures, the plants rapidly covered the sediment surface within the exclosures. Expansion beyond the exclosures was variable and occurred primarily during the cooler portions of the year when herbivory was assumed to be low. During the spring of the second growing season, herbivores cropped most of the previous expansion leaving only a narrow fringe of plants surrounding the exclosures. At Lewisville Lake, a large, turbid reservoir with significant seasonal water level fluctuations and no existing aquatic macrophytes, two native pioneer species (Potamogeton nodosus and Heteranthera dubia) were planted within exclosures. Good survival and growth occurred within undamaged exclosures, although no expansion ever occurred outside the fenced areas. Plantings of H. dubia in undamaged exclosures also showed excellent survival except for those planted in areas subject to very high turbidity and sedimentation rates. Again, herbivory prevented any expansion outside the protective exclosures. |
| The Effects of Benthivorous Smallmouth Buffalo (Ictiobus bubalus) on Water Quality and Nutrient Cycling in a Shallow Floodplain Lake | David E. Shormann; James B. Cotner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 270 - 278 | The Effects of Benthivorous Smallmouth Buffalo (Ictiobus bubalus) on Water Quality and Nutrient Cycling in a Shallow Floodplain Lake | Experimental mesocosm studies revealed that the presence of benthivorous smallmouth buffalo (Ictiobus bubalus) significantly enhanced turbidity, phytoplankton biomass, ammonium (NH4+), and total nitrogen (N) and phosphorus (P) concentrations in a shallow, aerobic, hypereutrophic oxbow lake. The effects of Ictiobuson water quality are similar to the results of experiments performed on other benthivorous fish species. Prior studies have suggested that enhanced phytoplankton biomass in the presence of benthivorous fishes is a result of P excretion by fish and physical relocation of sediment P to the water column. However, our results revealed that enhanced microbial NH4+ regeneration and subsequent uptake by phytoplankton may also be an important factor causing increased phytoplankton biomass levels in the presence of benthivorous fishes. Net sediment plus water column particle NH4+ fluxes were over six times higher in the presence of Ictiobus, relative to the control. Increased biological demand for phosphate, as well as adsorption to resuspended sediments, resulted in a significant increase in water column particle phosphate demand in the presence of Ictiobus, relative to the control. Furthermore, we estimated that approximately 60% of the increase in water column total N in the presence of Ictiobus, relative to the control, was attributed to increases in phytoplankton and bacterial biomass, while 77% of the P increase could be explained by physical resuspension of sediment P. |
| The Landscape Ecology of the Lake Simcoe Basin | Frederick M. Johnson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 226 - 239 | The Landscape Ecology of the Lake Simcoe Basin | The Lake Simcoe drainage basin is located in Southern Ontario, approximately 25 km north of Metropolitan Toronto. It occupies 3592 km2 with the land portion representing approximately 80% of the total area. The largest portion of the drainage basin is located to the south of Lake Simcoe in an area where streams flow north into the lake through a landscape highly modified by agricultural and urban activity. The entire basin is located in a transitional portion of the Southern Ontario landscape. In the southerly two thirds, deep fertile soils were deposited by glacial activity on top of limestone and shale bedrock. In the northerly third, thin soils are sparsely spread over a limestone, shale and granitic bedrock that has been exposed and eroded in many places by glacial action. The transitional nature of the basin, a varied geological past and over 200 years of intensive exploitation by European immigrants have created a complex ecological tapestry. The paper briefly explores the fundamental biophysical features and attributes of the basin. |
| Agricultural Pollution Control: Trends and Innovations in the Lake Simcoe Watershed | Michael R. Toombs | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 240 - 245 | Agricultural Pollution Control: Trends and Innovations in the Lake Simcoe Watershed | Agriculture represents 31 percent of the land use within the Lake Simcoe basin and contributes approximately 45 metric tons of phosphorus to the lake annually. Agricultural sources of phosphorus include livestock operations and soil erosion from cultivated land, fallow land and pasture. Rapid urbanization of the basin has been largely responsible for the decline of the number of farms and for some reluctance of the farming community to invest in larger capital remediation projects. Since the late 1980s, cost-share programs have been in place to reduce agricultural loadings to the lake. Over 300 remediation projects have reduced phosphorus loadings by an estimated 7.5 metric tons per year. With the increased costs of farming and rapid urbanization in the southern half of the basin, targeted programs and innovative low cost solutions, such as vegetative filter strips and flocculaters to treat milkhouse washwater systems, were developed to deal with agricultural pollution concerns. |
| Stream Monitoring and Stewardship Programme Involving a Partnership Between Community Organizations, High Schools and a University | G. Bae; R. F. Io; F. Lee; L. Lukasik; A. MacDougall; R. Martinez; J. Pullen; I. Wheeldon; O. Zaimi; G. Sorger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 246 - 252 | Stream Monitoring and Stewardship Programme Involving a Partnership Between Community Organizations, High Schools and a University | The long range aim of the programme described in this paper is to raise public awareness of water environmental issues to a point where meaningful and informed public participation in environmental decisions is possible. The approach to achieving this goal is as follows: Students from local high schools learn to monitor the level of coliform bacteria, E. coli, phosphate ions, ammonium ions, toxicity, using Daphnia magna, and other pertinent parameters (dissolved oxygen, hardness, pH, temperature) in streams, during a 5-week lab course. They do this as part of their curriculum study programme. An organization of citizens concerned with a local stream, in this case Red Hill Creek, then contacts the students and points out to them their concerns about sites along the creek. The students subsequently monitor the sites of concern using the skills they have learned, and either document causes for the community group's concerns or allay their fears through the information gathered. The quality of the data obtained by the students is very important to the success of the programme. A partnership in environmental stewardship is thus formed between the community group and a local high school. The students findings are presented at meetings organized by the community group and attended by the local authorities. In the cases reported herein the environmental authorities confirmed the students findings, and in most cases were stimulated to remedial action. The press was found to play a significant role in this process. |
| A Limnological Basis For A Lake Simcoe Phosphorus Loading Objective | K. H. Nicholls | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 189 - 198 | A Limnological Basis For A Lake Simcoe Phosphorus Loading Objective | Statistical relationships between 1) flushing-corrected total phosphorus (TP) loading rate and lake water TP concentration, 2) lake water TP and chlorophyll concentrations and 3) chlorophyll and temperature-corrected dissolved oxygen (DO) depletion rate have permitted the estimation of annual phosphorus loading rates of 89, 73, or 58 metric tons · yr-1 required to achieve end-of-summer volume weighted average DO concentrations of 4, 5, or 6 mg · L-1 in the 18-m to bottom zone of Lake Simcoe. These results are in good agreement with an independently developed deterministic model which showed that end-of-summer DO concentrations of 4, 5, or 6 mg · L-1 could be achieved by reductions in phosphorus loading to 89, 72, or 55 metric tons · yr-1. These models also hindcast a pre-settlement (circa 1800 AD) end-of-summer DO concentration of about 8 mg · L-1 in the zone of primary lake trout habitat. Present-day concentrations are in the 3 to 3.5 mg · L-1 range and apparently declined in response to an increase in TP loading from about 32 metric T · yr-1 in 1800 to about 100 metric T · yr-1 in the early 1990s. The proposed TP loading target of 75 metric T · yr-1 is predicted to generate a lake volume-weighted springtime (mixed water column) TP concentration of 9 to 10 μg P · L-1 (presently at about 12.7 μg P · L-1). As a water quality objective, this concentration is consistent with the guideline presently advocated by the Ontario Ministry of Environment and Energy which states '… a high level of protection against aesthetic deterioration will be provided by a total phosphorus concentration for the ice-free period of 10 μg · L-1 or less.' |
| An Overview of Fisheries Management for Lake Simcoe | M. J. McMurtry; C. C. Willox; T. C. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 199 - 213 | An Overview of Fisheries Management for Lake Simcoe | Eutrophication, increased fishing pressure, habitat destruction and invasion of non-native plants and animals have transformed Lake Simcoe and its assemblage of fishes over the past 150 years. Notable changes include die extirpation of lake sturgeon (Acipenser fulvescens), decline of muskellunge (Esox masquinongy), and failure of recruitment of lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis). Many species, including lake trout, lake whitefish, lake herring (Coregonus artedi), and yellow perch (Perca flacescens), have undergone major fluctuations in abundance. Fisheries management actions have evolved with changes in the lake ecosystem and changes in scientific knowledge. Early regulations substantially restricted the commercial fishery and imposed many of the existing controls on the sport fishery. Along period of adjustment and addition to these regulations along with reliance on supplemental stocking (i.e., stocking of a species where a self-reproducing population of that species exists) of native fish as well as introduction of non-native fish followed. In the last 3 decades, a scientific approach and ample monitoring have been established as basic requirements for making sound management decisions. Supplemental stocking of native species and stocking of non-native species have been largely replaced by stocking of native species for rehabilitation. Successful fisheries management in the future will need to address the uncertainty about the state of complex aquatic ecosystems, and identify the possible states of the system and the probable consequences of specific management actions. |
| Strategies to Rehabilitate Lake Simcoe – Modelling Phosphorus Loads, Remedial Measures and Control Options | Robert R. Walker | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 3 | 1997 | 214 - 225 | Strategies to Rehabilitate Lake Simcoe - Modelling Phosphorus Loads, Remedial Measures and Control Options | Average annual total phosphorus loads to Lake Simcoe are estimated at 100 metric tons. Urban sources of phosphorus such as water pollution control facilities and urban stormwater runoff account for approximately 30% of the total loading. Rural sources such as runoff from agricultural lands, leachate from septic systems, atmospheric deposition and soil erosion contribute the remaining 70%. A target load of 75 metric tons per year has been proposed to ensure an end-of-summer deep water dissolved oxygen concentration of 5.0 mg/L. To achieve the target load, it is necessary to reduce the export of phosphorus from the major controllable sources by 25 metric tons per year. Remedial measures and phosphorus control options to reduce point and non-point sources include controlling agricultural runoff, and erosion and urban stormwater runoff. Several management strategies have been evaluated using a GIS-assisted computer model called HYDROSIM which predicts changes in phosphorus loading in response to implementation of remedial measures within the Lake Simcoe watershed. Management scenarios examined the effectiveness of remedial options based on present and future conditions to ensure that the target load is achievable and sustainable. Modelling results indicate that the most substantial loading reductions can be achieved by controlling urban stormwater runoff and cropland soil erosion. Based on the implementation of an aggressive management program, the target load of 75 metric tons per year is considered to be achievable and can be maintained into the future. |
| A Zero Degree of Freedom Total Phosphorus Model; 2. Application to Lake Sammamish, Washington | Warren W. Perkins; Eugene B. Welch; Jonathon Frodge; Thomas Hubbard | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 131 - 141 | A Zero Degree of Freedom Total Phosphorus Model; 2. Application to Lake Sammamish, Washington | Current mean annual whole-lake total phosphorus (TP) concentration is about 20 mg·m-3, and mean June through September epilimnion TP is approximately 13 mg·m-3 in Lake Sammamish. Water quality is referenced to mean June through September chlorophyll a (chl a) and Secchi disk transparency. Currendy, these two parameters are at approximately 2.8 mg·m-3 and 4 meters, respectively. A dynamic deterministic TP simulation model indicates that lake water quality will decline, and future water quality in the lake is dependent upon die extent of land development and stormwater controls. The model simulated a lake that: 1) is seasonally stratified, 2) receives seasonal internal loading, and 3) receives seasonal variations in both external TP loading and hydraulic loading. TP movement into, out of, and within the lake was estimated based upon measured values for all of the major pathways. Past, present, and future water quality were estimated based upon the simulated TP concentrations and empirical relationships developed from both literature and in-lake relationships. |
| Transparency Measurements in Garner Lake, Tennessee: The Relationship between Secchi Depth and Solar Altitude and a Suggestion for Normalization of Secchi Depth Data | Gerrit L. Verschuur | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 142 - 153 | Transparency Measurements in Garner Lake, Tennessee: The Relationship between Secchi Depth and Solar Altitude and a Suggestion for Normalization of Secchi Depth Data | Measurements of Secchi depth in Garner Lake, TN, were made with and without a viewing tube at approximately 20-minute intervals from sunrise to sunset on 12 days throughout a year. The goal was to determine which factors affect the apparent Secchi depth as a function of time of day as well as date. The data show that on any given day the apparent (measured) Secchi depth depends on solar altitude. This relationship has been formally modeled. A key point in the model is that the magnitude of the observed Secchi depth is determined by the trajectory of a beam of sunlight through the water. The model calculations allow the Secchi depth observed at any date, time, or geographical location to be normalized to a standard, the value that would be found with the sun in the zenith. Use of such a normalization offers the opportunity to accurately quantify and study Secchi depth variations over time, or differences between lakes in different geographical locations. Based on the experience gained in this experiment, several suggestions are offered on how to obtain the most accurate measurements on any given day. |
| A Zero Degree of Freedom Total Phosphorus Model: 1. Development for Onondaga Lake, New York | Martin T. Auer; Susan M. Doerr; Steven W. Effler; Emmet M. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 118 - 130 | A Zero Degree of Freedom Total Phosphorus Model: 1. Development for Onondaga Lake, New York | A seasonal, two-layer, variable volume, mass balance model for total phosphorus in a stratifying eutrophic lake is developed and tested for a single spring to fall interval. The model recognizes settling, sediment release, and vertical mass transport as key in-lake processes mediating phosphorus dynamics. The application presented is termed a “zero degree of freedom†model, as all inputs are determined independently through field and laboratory studies conducted on a test system. The model is considered validated for the test system because simulation results closely match field observations with no calibration (adjustment of model coefficients). Loading reductions at an adjoining wastewater treatment plant, the lake's major phosphorus source, provided an opportunity for model verification. The model framework has utility for other eutrophic stratifying lakes and the “zero degree of freedom†approach will find application where opportunities for both calibration and verification do not exist. |
| The Influence of Drainage From the Las Vegas Valley on the Limnology of Boulder Basin, Lake Mead, Arizona-Nevada | James F. LaBounty; Michael J. Horn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 95 - 108 | The Influence of Drainage From the Las Vegas Valley on the Limnology of Boulder Basin, Lake Mead, Arizona-Nevada | Lake Mead, Colorado River, Arizona-Nevada, is one of the most heavily used reservoirs in the Western United States, providing abundant recreational opportunities as well as downstream domestic and agricultural water for over 22 million users. Based on average nutrient levels and productivity, Lake Mead is classified as mildly mesotrophic. The insertion into the water column of the Colorado River dominates the limnology of much of the 106 km-long reservoir, and may still be identified at Hoover Dam under certain conditions. The lower basin of Lake Mead ending at Hoover Dam is known as Boulder Basin and is near the Las Vegas metropolitan area. Las Vegas Bay, which comprises the northwestern portion of Boulder Basin, receives all runoff from the Las Vegas Valley via Las Vegas Wash. Inflow includes urban storm flows, secondary and tertiary treated municipal sewage effluent and groundwater seepage. The rapid increase in population of Las Vegas Valley and subsequent increased volume of point and non-point sources to Las Vegas Wash have produced noticeable physical and ecological changes in Las Vegas Bay, including eutrophication. However, the influence of the intrusion from Las Vegas Wash, which is easily identified by its relatively high specific conductance and turbidity, extends from Las Vegas Bay out into Boulder Basin, and at times, to Hoover Dam. The intrusion's depth, thickness, and the distance to which it extends into the reservoir depend on the season of the year and are related to the degree of thermal stratification within the reservoir. Limnological data on the extent of the intrusion to station LV14 suggest future studies should focus on examining the potential threat, under certain conditions, to subsurface municipal water intakes located at Saddle Island 2.5 km south of sampling station LV14. Concentrations of bacteria and organic compounds are higher in the intrusion than surrounding deeper or shallower water. |
| Changes in the Otsego Lake Macrobenthos Communities Between 1935 and 1994 | Willard N. Harman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 160 - 169 | Changes in the Otsego Lake Macrobenthos Communities Between 1935 and 1994 | Otsego Lake fills a depression formed by the overdeepening of the headwaters of the Susquehanna River in New York State. The lake is dimictic. During summer stratification hypolimnetic waters become oxygen depleted impacting cold-water fish habitat and resulting in changes over time in the distributions of profundal macroinvertebrates. Changes in benthic communities have occurred concurrent with changes in water quality, but not with precipitation. There is debate whether recent trends are due to meteorologically driven anomalies or to changing conditions due to human impacts on nutrient loading. Artificial changes in lake level, impacts of legislation, alterations of on-site sewage disposal and exotic introductions further complicate analysis. Eulittoral macrobenthic species richness was calculated by combining records of taxa collected from 1968-88 and comparing them to collections made from 1989-93. Lake wide average species richness has decreased 27.5%; EPT (pollution intolerant Ephemeroptera, Plecoptera and Trichoptera) species richness by 56.1%; and Mollusca by 52.9%. Invertebrate biomass from the shoreline to the deepest profundal substrates is represented by collections from 1935, 1969, and 1993. Biomass remained stable between 1935 and 1969, but increased by 1993. In 1968 mollusks dominated the eulittoral (air, water, land interface; the shoreline) environment; arthropods from 4-30 m in depth; and oligochaetes in the deepest waters. In 1993, the littoral benthic community was dominated by mollusks. The oligochaete annelids occupied substrates at middle profundal depths while the populations of fingernail clams and the Chironomidae in those regions had declined. |
| Use of Rhodamine-WT Dye to Map Effluent Mixing Zones in Lake Dillon, Summit County, Colorado | Kenneth J. Lull; Leo B. House; James A. Tindall | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 170 - 174 | Use of Rhodamine-WT Dye to Map Effluent Mixing Zones in Lake Dillon, Summit County, Colorado | The Breckenridge Sanitation District discharges tertiary-treated sewage effluent into Lake Dillon, Colorado, a major water supply reservoir for Denver. The effluent plume was mapped using rhodamine-WT dye during ice-covered and open-water conditions and compared to a criterion issued in a U.S. Environmental Protection Agency policy statement regarding mixing-zone dilution. Rhodamine-WT dye was used as a tracer and was injected directly into the sewage effluent at the outlet of the treatment plant. Dye concentrations were determined using fluorometric analysis. Dye-concentration isolines were determined by interpolation of a rectangular sampling grid. At all sampling locations, plateau dye concentrations were reached within 48 hours after injection began. Results indicated that the Breckenridge Sanitation District's effluent mixing zone extended 158.5 m (520 ft) into the lake during ice-covered conditions on March 15, 1995 (the date of maximum effluent discharge during the study period) and extended 64 m (210 ft) during open-water conditions on September 13, 1995. The EPA criterion for lakes specifies that the maximum allowable length of a mixing zone not exceed 61-m (200 ft). |
| Assessing Impacts of Past Human Activity on the Water Quality of Upper Saranac Lake, New York | J. Curt Stager; Peter R. Leavitt; Sushil S. Dixit | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 175 - 184 | Assessing Impacts of Past Human Activity on the Water Quality of Upper Saranac Lake, New York | Paleolimnological techniques were used to establish baseline environmental conditions as guidelines for lake management and to evaluate water quality changes over the last 300 years in the north basin of Upper Saranac Lake (Adirondack Park, New York). Analysis of diatoms, bulk sedimentary characteristics and fossil pigments in a 30-cm core showed that the lake was once oligo- to mesotrophic but has become increasingly productive since the turn of the century, especially since the early 1950's. Relative abundances of the diatoms Fragilaria crotonensis, Tabellaria flocculosa, and Asterionella formosa - common indicators of nutrient enrichment - increased in the most recent sediments, as did loss-on-ignition, cyanobacterial pigments, and inferred total phosphorus, pH, and chloride. Comparison of core profiles with historical data suggests that the productivity increased because of human activities, in eluding shoreline development and the discharge of fish hatchery effluent into a major tributary of the north basin. Short-term variations in diatom-inferred phosphorus since 1950 may be partly attributable to weather conditions. |
| Aquatic Vegetation Monitoring by Natural Resources Agencies in the United States | William Bartodziej; Judy Ludlow | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 109 - 117 | Aquatic Vegetation Monitoring by Natural Resources Agencies in the United States | Aquatic plant monitoring is becoming increasingly important to document the spread and introduction of nonnative plant species. This paper presents results from a telephone poll of state-agency biologists familiar with plant monitoring; natural resources agencies in all fifty United States were contacted. Twenty-seven states conduct some form of aquatic plant monitoring. Of the states without programs, fourteen believed that macrophyte monitoring was needed. Seven states conduct full-scale aquatic plant monitoring and twenty states have partial programs (i.e., a limited number of waters, selected species, or short-term). Although quantitative information is considered ideal, most states collect semi-quantitative data. The primary reason for this situation is a lack of funding — sixteen states conducting semi-quantitative monitoring believed that program expansion was necessary. Monitoring data are routinely used in formulating management strategies, most frequently for nonnative plant control. However, a number of native plants (e.g., Myriophyllum laxum) were listed as nuisance species, becoming the focus of control and monitoring programs in eight states. Based on the knowledge shared by the poll participants, a few general recommendations on aquatic plant monitoring are presented. |
| The Effects of Sediment Resuspension on Phosphorus Available for Algal Growth in a Shallow Subtropical Lake, Lake Okeechobee | Phyllis S. Hansen; Edward J. Phlips; Frederick J. Aldridge | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 2 | 1997 | 154 - 159 | The Effects of Sediment Resuspension on Phosphorus Available for Algal Growth in a Shallow Subtropical Lake, Lake Okeechobee | Algal bioassays were conducted to determine whether phosphorus available for algal growth was released during sediment resuspension in Lake Okeechobee. The bioassays included evaluations of resuspension of sediments at different times of the year. Treatments consisted of floc and surface sediment layers mixed with surface lake water, then filtered to remove all but soluble phosphorus. The presence of phosphorus available for algal growth was manifested as the growth responses of unialgal cultures of phosphorus-starved cyanobacteria isolated from Lake Okeechobee. Floc and sediment treatments caused different algal growth responses depending on the sampling dates. In two summer experiments, there was enhanced growth response of the algae in the surface water previously mixed with sediments and floc. This result contrasted with the winter experiments when algal yields were lower in surface water samples mixed with sediment or floc. The results support recent hypotheses that sediment resuspension in Lake Okeechobee can act as either source or sink for orthophosphorus. |
| Note on sampling a small, but important insect | Sallie P. Sheldon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 87 - 88 | Note on sampling a small, but important insect | |
| In Situ Responses of Lake Okeechobee (Florida, USA) Phytoplankton to Nitrogen, Phosphorus, and Everglades Agricultural Area Canal Water | Karl E. Havens; Therese East | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 26 - 37 | In Situ Responses of Lake Okeechobee (Florida, USA) Phytoplankton to Nitrogen, Phosphorus, and Everglades Agricultural Area Canal Water | Lake Okeechobee experiences blooms of cyanobacteria, perhaps due in part to the low nitrogen:phosphorus (N:P) ratios found in the water column, which may favor cyanobacteria over other phytoplankton taxa. The current strategy for managing the lake is to reduce external P loads. Some have recommended that pumping of N-rich water from the Everglades Agricultural Area (EAA), located adjacent to the south end of the lake, into Lake Okeechobee could increase N:P ratios and reduce cyanobacterial blooms until P loads are reduced. We conducted experiments to assess potential impacts of that strategy on phytoplankton in the lake's south pelagic region. Three in situ experiments were conducted during July 1994, with triplicated treatments (P, N, N+P, or EAA canal water additions) applied to 20-L clear plastic carboys, which were incubated in the lake for 3 days. In the first experiment, additions of P (50 μg · L-1) did not stimulate chlorophyll a or net primary productivity. Additions of N (500 μg · L-1) led to significant increases in both parameters. The greatest biomass and productivity increases (5-fold) occurred when the N and P were added together. In the second experiment, additions of N at 1X, 2X, and 4X the concentrations utilized in experiment 1 caused 3-fold increases in chlorophyll a and primary productivity. Nearly the same results were obtained in the third experiment, where EAA canal water was added to lake water in a 1:10 or 1:5 ratio, increasing soluble reactive P (SRP) by 17 and 34 μ · L-1, and dissolved inorganic nitrogen (DIN) by 175 and 350 μg · L-1, respectively. Although agricultural canal water often has been shown to contain herbicides which can suppress algal growth, no such effect was observed here. The yields of chlorophyll a per unit SRP or DIN in experiment 3, where canal water was added, were nearly identical to those in experiments 1 and 2, where N or N+P were added. In none of the experiments was there a shift from cyanobacteria to other algal taxa, despite the presence of small rapidly-growing chlorophytes in the lake water inoculum. The phytoplankton was dominated by cyanobacteria (70 to 81% of total phytoplankton densities), especially Lyngbya, Oscillatoria, Chroococcus, and Aphanocapsa, in all treatments, which encompassed DIN:SRP ratios from below 1:1 to over 140:1. From a management standpoint, these results indicate a potential for increased biomass of cyanobacteria in this N-limited lake if water pumping from the EAA were to be substantially increased. |
| Water Levels and Total Phosphorus in Lake Okeechobee | Karl E. Havens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 16 - 25 | Water Levels and Total Phosphorus in Lake Okeechobee | Pelagic total phosphorus (TP) concentrations in Lake Okeechobee were shown previously to be correlated with lake water levels, possibly due to littoral flooding and subsequent P release from vegetation (Canfield and Hoyer 1988). The present paper reviews the research to test this and other hypotheses to explain the water level - TP relationship. Research in the littoral region indicates that during low to intermediate water levels, there is little water or nutrient exchange between the pelagic and littoral regions, and that under high water levels, the littoral is a P sink. These findings lead to a rejection of the littoral flooding hypothesis. Alternative hypotheses, concerning internal loading from pelagic sediments, have been suggested. Maceina and Soballe (1990) proposed that wind, rather that water level, controls TP - in windy years, there is frequent resuspension of P-rich sediments into the water column. This hypothesis is supported by results of hydrodynamic model simulations, and by studies of sediment composition and sediment-water P transport. Also, there is evidence that horizontal P transport is enhanced by a combination of high wind and high water levels (Maceina 1993). There is an additional effect of high water levels that could increase TP concentrations - a greater thermal stability of the water column during summer could result in anoxic bottom waters and subsequent P release. Research results showing that Fe regulates soluble P transport between sediments and water in Lake Okeechobee, and findings that this process is a key one affecting internal loading in other shallow lakes, are supportive of this hypothesis. |
| Effects of Motor Boats on Submerged Aquatic Macrophytes | Timothy R. Asplund; Chad M. Cook | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 1-12 | Effects of Motor Boats on Submerged Aquatic Macrophytes | Excluding motor boats from small experimental plots in a lake with heavy boat traffic significantly increased macrophyte biomass, coverage, and shoot height compared to impacted areas. Lakes across the country are increasingly threatened by overuse, particularly involving more and larger motor boats. In recent years, Lake Ripley, located in Jefferson County in southern Wisconsin, has exhibited a decline in macrophyte abundance along with increased motor boat activity. To examine the possible connections between these two events, a study on the effects of motor boats on submerged aquatic macrophytes was conducted during the summer of 1995. Four enclosures, two of solid plastic and two of mesh fencing, were built in each of two areas in about 1 m of water adjacent to high boat traffic areas. These enclosures were intended to exclude motor boat access and, in the solid-walled enclosures, to block the turbidity generated by boat-induced sediment resuspension. Weekly water samples were collected for turbidity, suspended solids, dissolved oxygen, and temperature. At the end of the study, plant biomass, height and percent cover were measured inside the enclosures and in control plots. Our hypothesis was that motor boats limit macrophyte growth either directly by physical disturbance or more indirectly by generating turbidity which decreases light availability and therefore limits production and biomass. Results indicated that motor boats reduced plant biomass quite dramatically, primarily through scouring of the sediment substrate and direct cutting, but not through turbidity generation. |
| Effects of Fertilization on Phytoplankton in Kootenay Lake, British Columbia | Rowena M. Rae; Frances R. Pick; Paul B. Hamilton; Kenneth I. Ashley | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 57 - 66 | Effects of Fertilization on Phytoplankton in Kootenay Lake, British Columbia | Phytoplankton biomass, composition, and size structure were examined in oligotrophic Kootenay Lake, British Columbia, during two years of a fertilization program aimed at enhancing declining stocks of kokanee salmon. Phosphorus (47.1 metric tonnes per year) and nitrogen (206.7 metric tonnes per year) were added to the northern end of this long, narrow lake. Comparisons were made between the fertilized North Arm and unfertilized South Arm of the lake. The two arms did not indicate any significant differences in water chemistry prior to fertilization. Algal biomass was highest at the fertilized sites during the spring bloom (June) but did not differ between fertilized and unfertilized regions during the summer months (June 21 - September 21). There was an overall increase in biomass from 1992 (the first season of experimental nutrient loading) to 1993. Algal composition at the division level did not change between fertilized and unfertilized sites, except in 1993 when an increase in summer Chlorophyta was seen at the fertilization area relative to the unfertilized area. Diatoms dominated the phytoplankton community followed by Cryptophyta and Chrysophyta. The biomass of the nanoplankton (2 to 20 μm) and microplankton (20 to 64 μm) size fractions was not altered between fertilized and unfertilized sites in 1992, but there was an increase in net plankton (> 64 um) at the fertilized sites. In 1993, the average biomass of the nanoplankton had decreased at both sites while average microplankton biomass was significandy higher than in 1992. Photosynthetic picoplankton (0.2 to 2 μm) biomass was lower in the fertilized than in die unfertilized area on the one date of assessment in the summer of 1993, suggesting that fertilization may be shifting die energy flow in Kootenay Lake towards a more efficient classical food chain. |
| Decision Analysis to Guide Lake Okeechobee Research Planning | Kenneth H. Reckhow; Katrina Smith Korfmacher; Nicholas G. Aumen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 49 - 56 | Decision Analysis to Guide Lake Okeechobee Research Planning | Decision analysis provides an organized, logical frame work for decision making under uncertainty. In brief, decision analysis should begin with thorough identification of objectives, attributes, and feasible management actions, followed by development of a probability model to characterize uncertain science and a utility or net benefits function to represent value. This approach results in an analytic framework that may be used to guide decision making and to answer questions such as: (1) is scientific understanding sufficient to act now, or should additional information be obtained? (2) if additional information is needed, what scientific research and monitoring should be undertaken to provide this information? (3) what, if any, simulation model should be used to evaluate and present scientific information for decision support? These research and modeling issues are explored in an application of decision analysis to guide research planning for the management of eutrophication in Lake Okeechobee, Florida. This paper describes decision analysis, outlines the Lake Okeechobee eutrophication problem, and explains the importance of the simulation model in research prioritization. |
| Investigations on the Potential Use of an Aquatic Weevil to Control Eurasian Watermilfoil | Sallie P. Sheldon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 79 - 86 | Investigations on the Potential Use of an Aquatic Weevil to Control Eurasian Watermilfoil | Previous research has suggested that Euhrychiopsis lecontei, an aquatic weevil native to North America, may act as a biological control for Eurasian watermilfoil. To be able to predict which lakes weevils are likely to be effective in laboratory and field studies were carried out under a range of conditions. In the laboratory, weevils survived and reproduced in water up to 31°C, but not at 34°C. Weevils preferred Eurasian watermilfoil plants with no marl, but ate and laid eggs on marl-covered plants. The weevils preferred plants grown in richer sediment, but did eat and lay eggs on plants grown in poorer sediment After open water releases of weevils in three lakes, weevil populations were established and had a negative impact on Eurasian watermilfoil. We have followed a Eurasian watermilfoil decline from 1990-1995. Plant and weevil abundance have varied over the years; however, Eurasian watermilfoil has never regained its former dominance. Based on these trials, it appears that E. lecontei can survive and cause damage over a range of temperatures and plant conditions. Wider scale introductions would help determine the conditions under which this weevil is successful, and its limitations as a biological control for Eurasian watermilfoil. |
| Selection of a Model for Algal Blooms on Lake Okeechobee: an Application of Decision Analysis Using the Analytic Hierarchy Process (AHP) | Katrina Smith Korfmacher | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 38 - 43 | Selection of a Model for Algal Blooms on Lake Okeechobee: an Application of Decision Analysis Using the Analytic Hierarchy Process (AHP) | The South Florida Water Management District (SFWMD), like many environmental management programs, is faced with complex decisions about research and management. These decisions incorporate both qualitative and quantitative information, are often characterized by uncertainty, and usually involve multiple decision makers. A decision analysis system has been suggested to help the SFWMD make such complex decisions. Through a case study, this paper explores the potential of the Analytic Hierarchy Process (AHP) as a decision analysis tool. The AHP is applied to the selection by the SFWMD Research Department of a water quality model for blue-green algal blooms in Lake Okeechobee. The three models under consideration were Eutromod, Expert Elicitation (structured scientific judgment), and WASP4. In the case study of model selection, four respondents were interviewed using the AHP. Three of the four respondents chose WASP4 as the favored model; this was an unexpected result for two of the respondents. WASP4's success was largely due to the emphasis the respondents placed on accuracy and the high accuracy rating this model received. The AHP was shown to be useful in finding the sources of differences in opinion. Thus, the AHP results appeared to be a useful basis for group communication and decision making. Based on the case study experience, it seems likely that the AHP has the potential to aid numerous types of complex environmental management decisions. |
| Modification of Trap Nets to Reduce Capture of Common Loons | Joseph L. Christiansen; William L. Robinson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 13 - 15 | Modification of Trap Nets to Reduce Capture of Common Loons | All state licensed commercial fisheries taking lake whitefish (Coregonus clupeaformis) in Michigan waters of Lake Superior have been required to use trap nets since 1974. Trap nets are fished with pot depths (≤27.4 m (90 ft), which is within easy reach of deep diving common loons (Gavia immer). In 1993, some commercial fisheries began to modify (increase) the mesh size on the top of the net heart from 20.4 cm (8 in) stretched mesh to 30.4 cm (12 in) stretched mesh to allow loons to escape. In 1995, 3 fisheries were monitored to estimate catch and mortality of common loons. These samples represented 9% of the total annual trap net effort by these fisheries. Seven dead loons were found entangled both in the pots and in the hearts. None was caught in the heart of modified nets. The extrapolated annual catch of common loons was 77, with 43% of these caught in the hearts of unmodified nets, compared to 86% in unmodified nets before conversion. It appears that stretched mesh size of 30.4 cm reduces catch and mortality of common loons, thus a recommendation to convert tops of nets to large mesh is appropriate. |
| Effects of Reservoir Drawdown on Resuspension of Deltaic Sediments in Lake Powell | William S. Vernieu | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 67 - 78 | Effects of Reservoir Drawdown on Resuspension of Deltaic Sediments in Lake Powell | Due to prolonged drought conditions in the Upper Colorado River Basin, Lake Powell's water surface elevation declined steadily from 1988 to an early 1993 level approximately 27 m below the full pool level of 1130 m above MSL, resulting in a 60% reduction in reservoir storage. Associated with this drawdown was the exposure and resuspension of over 100 channel kilometers of deltaic deposits in the combined major tributary arms of the reservoir. This resuspension process maybe a significant source of nutrient and trace element loading to the reservoir due to the release of substances associated with these sediments. This may have implications to productivity processes and bioaccumulation of heavy metals in the aquatic ecosystem. In this study, 11 sites on the Colorado River and 3 sites in Dark Canyon, a small tributary in the inflow area of Lake Powell, were sampled for sediment concentration and size fractionation, nutrient concentrations, and total and dissolved trace element concentrations. Results showed most resuspension occurring in the lower part of the delta just before the river entered the lake. Significant increases in total nutrient and trace element concentrations were measured in a pattern similar to the increased sediment load. Dissolved nutrient and trace element concentrations remained very low but showed some increases in the active resuspension area. The inflow areas of the reservoir are typically the most biologically active and have shown increased biological activity during the recent drawdown years. In addition to the resuspension process, other physical and biological processes, along with the fate of the inflow current within the reservoir, play a significant role in making substances associated with the sediments in inflow areas available to the aquatic ecosystem. |
| Uncertainty Analysis and Simulation Modeling for Lake Okeechobee Research Prioritization | Kenneth H. Reckhow; Nicholas G. Aumen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 13 | 1 | 1997 | 44 - 48 | Uncertainty Analysis and Simulation Modeling for Lake Okeechobee Research Prioritization | A decision analytic framework and the USEPA mechanistic water quality model WASP4 were used to prioritize research and monitoring needs to address the water quality management objective, reduce algal blooms to an acceptable level in Lake Okeechobee. With the WASP4 model as a scientific assessment framework, proposed research and monitoring projects should be evaluated for their effectiveness in reducing WASP4 prediction uncertainty. Sensitivity analysis based on either model calculations or expert judgment may be used to estimate the reduction in prediction uncertainty associated with proposed projects. A utility-based approach can then be developed to select from among proposed research and monitoring projects. Selected projects may be expected to provide scientific information to reduce model prediction uncertainty for the use of the model in decision making. |
| Aquatic Weeds and Their Control in New Zealand Lakes | John S. Clayton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 477 - 486 | Aquatic Weeds and Their Control in New Zealand Lakes | This paper reviews some of the major aquatic weeds in New Zealand lakes and discusses some of the problems they cause. Approaches to the management of nuisance weed beds are also discussed. New Zealand's indigenous aquatic flora has proved susceptible to invasion with many of our marginal and submerged species being replaced by dense, tall-growing weed species. A variety of management approaches are discussed including 'leave alone' strategies and targeted control of nuisance weed beds. Mechanical control of nuisance weeds has tended to focus on problems associated with strandings (e.g., removal of shoreline strandings and at hydroelectric station intakes), but refinement of removal methods at their source is continuing. Chemical control of aquatic weeds is an effective option for target weeds of national importance (e.g., water hyacinth and salvinia) and for specific waterbodies where an acceptable degree of selective control can be achieved. Research results using grass carp have confirmed eradication of Egeria is possible in small waterbodies and this may be followed by native plant recovery; while similar trials on Hydrilla have achieved effective control, but the question of eradication is still unresolved on account of continuing tuber viability within lake sediments. |
| The Application of an Analytic Element Model to Investigate Groundwater-Lake Interactions at Pretty Lake, Wisconsin | Randy J. Hunt; James T. Krohelski | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 487 - 495 | The Application of an Analytic Element Model to Investigate Groundwater-Lake Interactions at Pretty Lake, Wisconsin | Pretty Lake is a 64 acre, sandy-bottomed groundwater flow-through lake that has a history of hydrologic disturbance. Residents and regulators require a better understanding of lake-groundwater interaction to develop measures to protect the lake's hydrologic system and water quality. A groundwater flow model was constructed as a tool to synthesize field data collected at the site, delineate recharge areas that supply groundwater to the lake, and predict die effect of dredging an adjacent drainage ditch. The one layer, two-dimensional steady-state areal model used analytic element (AE) methods because they are quick to apply and include sophisticated simulation of groundwater-surface water interaction. The model calibrated well to groundwater heads (mean absolute difference = 0.05 m), lake stage (within 0.05 m) and ditch fluxes (mean absolute difference = 0.0023 m3·s-1). Model results showed that a single 1000 m wide recharge area supplies all the groundwater inflow to the lake. In addition, the model predicted that dredging an adjacent ditch by 3.0 m would lower the lake level by 0.31 m. The analytic element model was verified using a widely accepted finite-difference (FD) code; differences were less than ±0.015 m near die lake area and reached a maximum of 0.08 m at far corners of the FD grid. These differences are likely a result of die nodal interpolation inherent to FD techniques and error associated with applying a discrete boundary to die AE infinite aquifer. Although developed recently, AE methods have great potential to aid characterizations of groundwater-lake systems. |
| Hypolimnetic Aeration with Hollow Fiber Membranes | Peter T. Weiss; John S. Gulliver; Michael J. Semmens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 468 - 476 | Hypolimnetic Aeration with Hollow Fiber Membranes | Microporous, hollow fiber membranes have potential for use as a lake hypolimnetic aerator because oxygen is transferred without bubble formation. Thus, the large capital costs of traditional hypolimnetic aerators can be avoided. Two hollow fiber aerator designs are considered for application to hypolimnion aeration. The first was a passive design that required no external energy input other than a pressurized oxygen supply. This approach was dismissed, however, because the low velocities which exist in lake hypolimnia result in oxygen transfer rates that are too small to provide cost-effective aeration. An alternative design, in which membrane modules were rotated through the water by a mechanical motor, was also examined. Experiments were conducted to characterize fiber performance for this design as a function of relative water velocity, and examine the effects of fouling on membrane performance. The experimental results were used to assess capital and operating and maintenance (O&M) costs of a rotating membrane aerator. The estimated costs compare favorably with the known costs of conventional lake aerators, indicating that this is a potentially viable new technology. |
| Trophic State of Clear and Colored, Soft- and Hardwater Lakes with Special Consideration of Nutrients, Anoxia, Phytoplankton and Fish | Gertrud K. Nürnberg | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 432 - 447 | Trophic State of Clear and Colored, Soft- and Hardwater Lakes with Special Consideration of Nutrients, Anoxia, Phytoplankton and Fish | Idiosyncrasies, erroneous assumptions and gaps are still hampering lake evaluations, despite several decades of defining the trophic state of lakes. I reevaluated nutrient and algal biomass limits that group lakes into oligo-, meso-, eu- and hyper eutrophic lakes at transition concentrations of 10, 30 and 100 μg · L-1 average total phosphorus concentration of the summer epilimnion. I investigated the direct and indirect effects of general lake characteristics like morphometry and geochemistry (water hardness and color) on lake trophic state and formulated models to deal with their significant influences. Nutrient and biomass concentrations as well as quantitative measures of anoxia were used to determine the trophic state. I demonstrated that the number of coldwater fish species may be used to classify the lower trophic levels in geographically constraint areas. Limits and models were established with data from well-studied lakes and verified with literature data from worldwide lakes. Trophic state limits were set for oligo-, meso-, eu- and hypereutrophic lakes at transition concentrations for average total nitrogen of 350, 650 and 1,200 μg·L-1, for summer chlorophyll of 3.5, 9 and 25 μg·L-1, for summer transparency (Secchi disk depth) of 4, 2 and 1 m, for die anoxic factor of 20, 40 and 60 d·summer-1, and for the areal oxygen depletion rate of 250, 400 and 550 mg·m-2·d-1. |
| Predictability of Phosphorus Load, Hydrological Load and Lake Total Phosphorus Concentration | Gregory C. Scarborough; Robert H. Peters | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 420 - 431 | Predictability of Phosphorus Load, Hydrological Load and Lake Total Phosphorus Concentration | One goal for eutrophication research is to predict lake trophic state without extensive field programs. However, existing comparisons of predicted:observed TP (total phosphorus) concentration calculate the former from measured watershed characteristics that require field sampling. Predictions of lake TP based on estimated rather than measured components are probably much less powerful, but this possibility should be quantitatively assessed. To assess the predictive power of current mass-balance models of eutrophication, measured estimates of volumetric water discharge (Qobs: m3·yr-1, n=110) and phosphorus load (Lobs: mg·m-2·yr-1, n=96) from lakes in the OECD (Organization for Economic and Cooperative Development) eutrophication data set were compared to calculated values of Q (Qcal) and 16 different variants of calculated phosphorus loading (Lcal, respectively. For the entire data set, Qcal was unbiased and strongly correlated with Qobs. In regional comparisons, some Lcal variants correlated well with Lobs, but others did not, and no single variant was significantly better than all of the others. In these comparisons, up to 95% of the variance in Lobs was explained by a single regional Lcal variant, but the best regression of a single variant against Lobs for the entire data set explained only 58% of its variance. Stepwise multiple regression to improve prediction of Lobs produced the following model; Log Lobs = 1.23 + 0.81 (log Lbest) + 0.19(G) - 0.42(%F) - 0.38(%U)- 0.11 (log Ad); R2 = 0.75, Sxy = 0.37, P < 0.001 where; Lbest - a composite variable consisting of the best performing Lcal variables in geographically limited regressions, G - watershed geology (1-igneous, 1.5-mixed igneous-sedimentary, 2-sedimentary), %F and %U - percentage of the watershed covered by forest and urban areas, respectively, and Ad - drainage basin area (m2). Finally, when a phosphorus budget model was used to predict lake TP concentration with (A) estimated components, (B) estimated components where Lcal, was adjusted for bias with the above equation, and (C) measured components, predictions of lake TP from all three estimates were of equal accuracy indicating that no estimate was better than the others. |
| The Ecology of Science Policy | Robert H. Peters | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 407 - 419 | The Ecology of Science Policy | Although science has grown faster than its resources for over 300 years, this situation is unstable. Eventually, the growth of science must slow to match that of its base, and researchers will have to compete harder. Verbal models of ecological competition provide scenarios of the likely conditions in the competitive science of the future. Individual researchers can expect to be more stressed and less productive. The scientific population will be more stable, reducing the youthfulness and immediacy of contemporary science, allowing the dominant individuals who succeed in fierce competition greater opportunity to impose theirviews. Science as a whole should expect more interdisciplinary infighting for available funds, and the largest subdisciplines will likely win even larger shares of the available pie. In a recent reallocation in Canada, aquatic sciences and related areas lost funds to supposedly more industrially and economically relevant fields, even though Canadian aquatic scientists outperform those competitors in terms of refereed publication and citation. Since the dominance of the USA is less marked in aquatic sciences, American aquatic scientists could find themselves competitively weak in funding reevaluations. A consequent reduction in American support would be a serious blow to the entire field. Researchers can compete by accepting the new conditions in science and using them to their advantage while applying their skills to the world's immediate problems. On the other hand, researchers can redimension their expectations to their resources. |
| Hypolimnetic Oxygen Deficits and Anoxic Factors in Garner Lake, a West Tennessee Reservoir | David H. Kesler; Gerrit L. Verschuur | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 462 - 467 | Hypolimnetic Oxygen Deficits and Anoxic Factors in Garner Lake, a West Tennessee Reservoir | Oxygen demand and anoxic factor values were calculated for Garner Lake, a 96-ha reservoir in Shelby County, Tennessee during 1994 and 1995. This physically unique reservoir of the West Tennessee Plain physiographic region has a mean depth of 5.5 m and very high total phosphorus concentrations (concentrations often above 100 μg · L-1 and a maximum value of 1510 (μg · L-1). Areal hypolimnetic oxygen deficit (AHOD) values were 234 and 182 mg · m-2 · day-1, and anoxic factors (AF) were 17.7 and 13.0 days · year-1 in 1994 and 1995, respectively. AHOD and AF values predicted from phosphorus and lake morphometry are much higher than observed values. Several causes could explain Garner Lake's lower than expected AHOD and AF values: 1) it is a southern reservoir and may function differently from more northern, dimictic lakes upon which the models are based, 2) it had been fertilized in 1993. |
| The Effects of Mechanical Harvesting of Floating Plant Tussock Communities on Water Quality in Lake Istokpoga, Florida | Shawn K. Alam; Lothian A. Ager; Tom M. Rosegger; Ted R. Lange | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 455 - 461 | The Effects of Mechanical Harvesting of Floating Plant Tussock Communities on Water Quality in Lake Istokpoga, Florida | The effects of harvesting floating plant tussock communities by mechanical methods on selected water quality parameters in Lake Istokpoga, Florida were examined. Dissolved oxygen, temperature, pH, conductivity, turbidity, chlorophyll a, and nutrients (nitrogen and phosphorus) were compared under pre-harvest, harvest and post-harvest conditions. Water quality data were compared between one tussock harvest site and three reference sites (30 m, 61 m, and 91 m away from the harvested plot). Very minor, although statistically detectable (p < 0.05), DO differences occurred at harvest site. Chlorophyll a, total nitrogen and total phosphorus concentrations decreased significantly during the harvest. Loadings of total nitrogen concentrations in Lake Istokpoga could be reduced by harvesting of floating plant communities in the littoral areas. A significant increase in turbidity and dissolved solids occurred during mechanical harvesting in both the harvested plot and the reference site 30 m away. |
| Limnological Effects of 19th Century Canal Construction and Other Disturbances on the Trophic State History of Upper Rideau Lake, Ontario | Catherine E. Christie; John P. Smol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 4 | 1996 | 448 - 454 | Limnological Effects of 19th Century Canal Construction and Other Disturbances on the Trophic State History of Upper Rideau Lake, Ontario | Upper Rideau Lake is a major lake in the Rideau Canal system; a waterway constructed in 1832 to link Kingston with Ottawa. The lake is currently borderline eutrophic, and local residents are concerned about its water quality. Long-term water chemistry data, however, are not available, and so we used diatom-based paleolimnological techniques to reconstruct the lake's development over the last two centuries. Our data indicate that Upper Rideau Lake was moderately productive even before European settlers began to affect this part of Ontario. The construction of the Rideau Canal, the first major anthropogenic disturbance in this system, greatly affected water quality. During the construction of the canal, the water level in Upper Rideau Lake was raised 1.5 m, resulting in increased nutrient and sediment loading, and an enlarged littoral zone. Deforestation associated with timber harvesting and agricultural activities maintained higher nutrient levels between ca. 1830 and the 1940s. Nutrient levels increased again over the last 40 years, with increased cultural activities in the drainage basin. Notwithstanding these more recent disturbances, the construction of the Rideau Canal in the early part of the 19th century had the largest impact on this lake. |
| Seasonal Variation of Nutrients and Heavy Metals in Phragmites australis of Lake Trichonis, Greece | Nikolaos P. Nikolaidis; Theodoros Koussouris; Thomas E. Murray; Ilias Bertahas; Aristidis Diapoulis; Konstantinos Gritzalis | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 3 | 1996 | 364 - 370 | Seasonal Variation of Nutrients and Heavy Metals in Phragmites australis of Lake Trichonis, Greece | Farming practices and other anthropogenic influences have affected the water quality and shifted trophic state of Lake Trichonis, western Greece, from oligotrophic to oligo-mesotrophic. This change has been accompanied by an expansion of dense reed beds of Phragmites australis in places where limited growth existed in the past. This study measured the seasonal changes in nutrients and heavy metals in the reed beds of Lake Trichonis, and assessed the applicability of reed harvesting on maintaining or improving the water quality of the lake. The results have illustrated three types of accumulation dynamics of nutrients and heavy metals in the reeds of Lake Trichonis. The first type shows maximum accumulation occurring early in the growing season and gradually declining throughout the year. P, K, Cl and NO3 follow this type of accumulation. The second pattern followed by fluoride, showed constant accumulation throughout die year. The third accumulation pattern, followed by Na, Zn, Cd, Co, Mn, Fe, Mg, Ca, Cu, Al, Ni, Cr, and SO4, showed increases in accumulation throught the growing season, reaching a maximum in August and September and then declined steadily. The reeds beds are a significant sink for nutrients in the early growing season and a potentially significant source of nutrients later in the season. The results indicate that removal of the reeds in the early spring would remove a large reservoir of potentially mineralizable P from the lake. To properly control the flow of nutrients and heavy metals in a lake through reed harvesting, the dynamic cycling of P and die seasonal changes in accumulation should be considered. |
| Nutrients and Metal Contaminants Status of Urban Stormwater Ponds | T. Mayer; J. Marsalek; E. Delos Reyes | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 3 | 1996 | 348 - 363 | Nutrients and Metal Contaminants Status of Urban Stormwater Ponds | Stormwater detention ponds are one of the management options designed to reduce pollution of the receiving water bodies by urban runoff. Many such structures are operated in the Greater Toronto Area. A seasonal survey of four stormwater detention ponds was conducted to estimate the inventories of heavy metals and phosphorus in bottom and suspended sediments. The concentrations of heavy metals in suspended and bottom sediments suggest that land use has the most profound impact on the quality of suspended and deposited sediments, with the pond in an industrial/commercial catchment having the highest metals concentrations, followed by ponds located in the residential catchments. The suspended and bottom sediments data suggest that the removal of heavy metals in these reservoirs may not be adequate. Apart from land use, the magnitude of runoff and seasonal conditions impacted the sediment and water quality in these ponds. The deleterious effects of restricted water circulation during the dry summer conditions and under the winter ice cover are apparent from the elevated levels of ammonia-N, sometimes reaching or exceeding the levels recommended by the Canadian Water Quality Guidelines (CCREM 1987) for the protection of aquatic life. |
| Compliance With Water Quality Criteria in a Multiple-Use Lake, Lake Okeechobee, Florida | R. Walter Ogburn III; Charles Hanlon; Steven W. Gong; Ellen Broughton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 3 | 1996 | 371 - 380 | Compliance With Water Quality Criteria in a Multiple-Use Lake, Lake Okeechobee, Florida | Lake Okeechobee, Florida, is managed for multiple uses, including drinking water supply, recreation, wildlife habitat, and flood control. Because much of the drainage basin is in agricultural production, maintenance of water quality conditions is a major management consideration for the lake. An evaluation of water quality data collected over a 20-year period indicated that Lake Okeechobee and its major inflows generally comply with applicable numerical criteria, and that parameters that exceeded criteria at inflows have not impaired die designated uses of the lake. Of 59,781 water quality measurements, 6,409 (10.7 percent) exceeded the applicable criteria. For most monitored parameters, values that exceeded criteria generally represented less than 25 percent of die measurements at specific locations. Exceptions included dissolved oxygen (DO) andiron. Low DO values (>5.0 mg·L-1) represented 9 to 100 percent of measurements at inflow stations, although fewer than one percent of the observations at any in-lake station were below die criterion. Iron values were commonly higher than die applicable criteria at many inflow and in-lake stations. However, most of die high iron values were greater than the secondary drinking water standard, and very few were greater than the criterion for protection of aquatic biota. Trace metals (including mercury) and organic contaminants were rarely greater than die criteria in the lake and its inflows, in spite of die predominance of agriculture in die basin. Pesticide application methods, degradation processes and dilution appear to be responsible for the generally low concentrations of pesticides and herbicides in Lake Okeechobee and its inflows. Many of the criteria that were exceeded are drinking water standards that do not relate to protection of aquatic biota. Because of water treatment processes, they do not appear to have affected die suitability of the lake as a potable water supply. Additional monitoring of biological conditions, in conjunction with continued monitoring of selected water quality parameters, is recommended to document whether die lake and its inflows meet their designated uses. |
| Evaluation of the Effects of Nutrient Removal and the “Storm of the Century†on Submersed Vegetation in Kings Bay – Crystal River, Florida | Julia B. Terrell; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 3 | 1996 | 394 - 403 | Evaluation of the Effects of Nutrient Removal and the “Storm of the Century†on Submersed Vegetation in Kings Bay - Crystal River, Florida | Municipal wastewater effluent was removed in 1992 from a cove (Cedar Cove) of Kings Bay in an attempt to reduce the bay's ambient total phosphorus (TP) and total nitrogen (TN) concentrations. Many citizens and professionals viewed nutrient removal as the solution to reducing the bay's nuisance growths of aquatic macrophytes and filamentous algae. Wastewater removal reduced average TP from 105 μg·L-1 to 27 μg·L-1 and average TN from 620 μg·L-1 to 220 μg·L-1 in Cedar Cove. TP (24 μg·L-1 to 28 μg·L-1) and TN (300 μg·L-1 to 260 μg·L-1), however, were not significantly reduced in southern Kings Bay. There were no significant changes in mean frequency of occurrence of vallisneria in Cedar Cove (0% to 1%) or southern Kings Bay (19% to 22%). Average hydrilla occurrence decreased significantly after wastewater removal in Cedar Cove (54% to 36%) and southern Kings Bay (61% to 35%). Eurasian watermilfoil occurrence significantly increased in Cedar Cove (6% to 24%) and southern Kings Bay (11 % to 32%). Filamentous algal occurrence in Cedar Cove averaged 34% prior to and 40% after wastewater removal. In southern Kings Bay, the frequencies of occurrence averaged 5% and 2%, respectively. If removal of Crystal River's wastewater discharge was responsible for the differences detected in plant abundances, die same reductions/increases in species abundance should not occur in Cedar Cove as in southern Kings Bay. Significant changes in plant occurrence were attributed to the March 13, 1993 “Storm of die Century,†not to die removal of wastewater. Further nutrient control is not recommended as an option for reducing nuisance growths of submersed aquatic vegetation in Kings Bay-Crystal River, Florida. |
| Setting Restoration Goals for an Acid and Metal-Contaminated Lake: A Paleolimnological Study of Daisy Lake (Sudbury, Canada) | Aruna S. Dixit; Sushil S. Dixit; John P. Smol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 3 | 1996 | 323 - 330 | Setting Restoration Goals for an Acid and Metal-Contaminated Lake: A Paleolimnological Study of Daisy Lake (Sudbury, Canada) | Many lakes in the Sudbury region of Ontario have been affected by acidic and metal inputs as a result of local smelting operations. Several initiatives are now underway to restore some of these systems. Long-term limnological data are rarely available, therefore lake managers must use proxy methods to set reasonable targets for lakes undergoing mitigation. Daisy Lake is presently an acidic (pH 4.7), metal-contaminated lake (Ni=370 μg L-1; Al=350 μg L-1), that has been selected for mitigation efforts. We used fossil pollen analysis to reconstruct past changes in terrestrial vegetation, and paleolimnological techniques (primarily diatoms and chrysophytes) to identify pre-disturbance conditions and to reconstruct past changes in water quality variables in Daisy Lake. Our data indicate that, if Daisy Lake and its watershed are limed to restore the lake to a state that approximates the pre-disturbance natural pH, the lake water pH has to be about 1.5 pH units higher than its present level. |
| Reconstructing Historical Changes in Everglades Plant Community Composition Using Pollen Distributions in Peat | Susan M. Bartow; Christopher B. Craft; Curtis J. Richardson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 3 | 1996 | 313 - 322 | Reconstructing Historical Changes in Everglades Plant Community Composition Using Pollen Distributions in Peat | During the past century, the historical hydrology and nutrient regimes of the Everglades, a 700,000 hectare freshwater wetland in southern Florida, have been altered by agricultural and urban development. Changes in plant community composition (e.g. encroachment of cattail (Typha domingensis Pers.) into sawgrass (Cladium jamaicense Crsntz) and slough communities) have been observed in areas receiving nutrient and water loadings from agricultural activities. The distribution of 210Pb and pollen in depth increments of peat was measured at a nutrient-enriched site and an unenriched site in Water Conservation Area 2A (WCA 2A) to describe how nutrient enrichment and water management might have altered the historical plant species composition of the Everglades. Species composition of the plant communities has changed during the past 20 to 50 years at both enriched and unenriched sites. At the unenriched location, there has been a general shift in community composition since 1950 as slough species (arrowhead (Sagittaria spp.), water lily (Nymphaea spp.)) have decreased and terrestrial plants (pigweed (Amaranthaceae), ragweed (Ambrosia spp.), and Eupatorium spp.) have increased. The nutrient-enriched site also has seen an increase in terrestrial plant species since about 1950. In addition, since 1970, the sawgrass and slough communities at the enriched site have been replaced by a cattail-dominated community. The increase in terrestrial vegetation at both sites since 1950 could be due to drainage activities (construction of canals and levees) along the eastern perimeter of the Everglades and in the Everglades Agricultural Area (EAA) during the 1950s. The increase in cattail and concurrent decline in slough species at the nutrient-enriched site since 1970 probably is the result of the massive inputs of water (459,000,000 m3yr-1) and nutrients (1814 MT Nyr-1, 60 MT Pyr-1) from the EAA since WCA 2A was impounded in 1961. |
| Risk Analysis of Total Maximum Daily Loads in an Uncertain Environment Using EUTROMOD | W. Cully Hession; Daniel E. Storm; C. Thomas Haan; Kenneth H. Reckhow; Michael D. Smolen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 3 | 1996 | 331 - 347 | Risk Analysis of Total Maximum Daily Loads in an Uncertain Environment Using EUTROMOD | A two-phased Monte Carlo procedure is presented for estimating the probability distribution of annual phosphorus load to a lake and the response of the lake to the load. A watershed-level nutrient loading and lake response model, EUTROMOD, and a geographic information system (GIS) were used. The uncertainty in loading and lake response due to natural variability and parameter uncertainty were propagated separately throughout the analysis. The methodology was applied to Wister Lake in Oklahoma with the lake and its trophic state as the endpoint for total maximum daily load (TMDL) analysis. The watershed contributing to Wister Lake covers approximately 260,000 ha and contains a variety of point and nonpoint sources of pollution contributing to the degradation of the lake. Model results compared well with measured water quality data. EUTROMOD simulations indicated that the lake is eutrophic under current land use and management conditions. Nonpoint source (NPS) pollution was estimated to contribute nearly 90 percent of the annual phosphorus load with the remainder attributed to point sources. The majority of this NPS load was attributed to agriculture. Alternative management evaluations indicated that an average reduction of agricultural NPS loads by 25 and 35 percent would be needed to meet our water quality goal with and without point source controls, respectively. Due to uncertainties inherent in the evaluation procedure, the required reductions had large confidence intervals which must be taken into consideration in the decision making process. |
| A Phosphorus Budget, Model, and Load Reduction Strategy For Lake Champlain | Eric Smeltzer; Scott Quinn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 3 | 1996 | 381 - 393 | A Phosphorus Budget, Model, and Load Reduction Strategy For Lake Champlain | A phosphorus budget and mass balance model were developed for Lake Champlain in order to identify load reductions necessary to attain interim in-lake total phosphorus concentration criteria established in a water quality agreement between New York, Quebec, and Vermont Total phosphorus loadings were measured from 31 tributaries, 88 wastewater discharges, and direct precipitation. Mean annual tributary loadings were estimated using the FLUX program (Walker 1987). The total base year phosphorus loading rate of 647 mt·yr-1 included 29% from point sources, 47% from cultural nonpoint sources, and 24% from natural sources. A mass balance model for 13 lake segments was developed and calibrated to the data using the BATHTUB program (Walker 1987). Exchange flows between lake segments were evaluated using a mass balance for chloride. The BATHTUB program error analysis procedure was used to evaluate model prediction uncertainty, based on variance estimates for all input data terms. The modeling results were used with a minimum-cost optimization procedure to determine that an overall phosphorus load reduction of 192 mt·yr-1 distributed among specifically targeted lake segment watersheds will be needed to attain the in-lake phosphorus criteria. |
| Ecology of Kokanee Salmon and Rainbow Trout in Crater Lake, Oregon | Mark W. Buktenica; Gary L. Larson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 2 | 1996 | 298 - 310 | Ecology of Kokanee Salmon and Rainbow Trout in Crater Lake, Oregon | Originally barren of fish, Crater Lake was stocked with approximately 1.8 million salmonids from 1888 to 1941. Rainbow trout (Oncorhynchus mykiss) and kokanee salmon (O. nerka) now inhabit the lake. This study was conducted from 1986 to 1991 to document and compare kokanee salmon and rainbow trout ecology in the lake to better evaluate the ecological implications of the presence of these non-native fish. Kokanee salmon exhibited cyclic patterns in population age structure, condition, abundance, and biomass from 1986 to 1991. One dominant year class of relatively low abundance and high condition was present from 1986 to 1987. Multiple year classes with increasing abundance and decreasing condition were present from 1989 through 1991. Rainbow trout maintained a diverse population structure throughout the study with a trend toward a relative increase of older age classes and larger fish. Vertical and horizontal migrations of kokanee salmon occurred within and between the nearshore and offshore zones of the lake. Rainbow trout were located along the edge of the lake. Kokanee salmon fed primarily offshore on zooplankton and small-bodied insects. Kokanee salmon cropped the Daphnia population and altered the zooplankton community structure during the study period. Rainbow trout fed nearshore on large-bodied vertebrates and invertebrates. Introduced fish in Crater Lake exhibited the potential to impact limnetic and benthic community structure and nutrient flux within and between these communities. |
| Zooplankton Assemblages in Crater Lake, Oregon, USA | Gary L. Larson; C. David McIntire; Robert E. Truitt; Mark W. Buktenica; Elena Karnaugh-Thomas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 2 | 1996 | 281 - 297 | Zooplankton Assemblages in Crater Lake, Oregon, USA | The zooplankton community in Crater Lake was comprised of 11 rotifer species and 2 species of cladocerans. Most zooplankton taxa were distributed in winter and spring from the lake surface to a depth of about 200 m, the maximum depth of mixing of lake waters by wind energy. The distribution of zooplankton species was partitioned in the water column to a depth of 200 m during summer and fall, which corresponded to the period when the lake was thermally stratified. At that time of year, zooplankton density in die upper 20 m of the water column was very low, whereas highest densities were found in the depth interval between 80 and 120 m. Closely related or competing species were found in different portions of the water column. Daphnia pulicaria the largest cladoceran species, was cyclic in abundance, and its density corresponded to patterns of lake productivity and fish predation. When D. pulicaria was abundant, abundances of rotifers and Bosmina longirostris declined and changes in the vertical distribution of Bosmina were observed. Relationships between variations in Secchi disk clarity and zooplankton abundances in the upper 40 m of the water column were not obvious. |
| Chemical Solute Mass Balance of Crater Lake, Oregon | Peter O. Nelson; Joseph F. Reilly; Gary L. Larson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 2 | 1996 | 248 - 258 | Chemical Solute Mass Balance of Crater Lake, Oregon | Crater Lake covers the floor of the caldera at the top of Mount Mazama. Surrounded by steep walls, the water surface of the lake occupies 78 percent of the catchment basin. No major rivers empty into the lake, and there is no surface outlet Based on a chemical solute mass balance model, mass inputs of major solute chemical components (Na, Ca, K, Mg, SO4, Cl, Si, and HCO3) from atmospheric deposition and caldera springs do not equal the mass output in seepage from the lake. One or more previously unquantified sources must be present in the lake or watershed system to account for the calculated deficits of mass inputs which range from 50 to 90 percent of mass outputs. A hydrothermal source, with a flow rate of approximately 6 percent of me seepage rate and chemical composition similar to saline fluids found in isolated pockets on the bottom of Crater Lake and to hydrothermal springs in die Cascade Mountain Range, could account for the calculated input mass deficits for major solute chemical components. Atmospheric bulk deposition (wet plus dry) may account for up to 90 percent of nitrogen and 30 percent of phosphorus inputs to Crater Lake. A net removal of nutrients from the lake water column occurs through internal processes, most likely burial of cellular debris in sediments. |
| Temperature, Water Chemistry, and Optical Properties of Crater Lake | Gary L. Larson; C. David McIntire; Michael Hurley; Mark W. Buktenica | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 2 | 1996 | 230 - 247 | Temperature, Water Chemistry, and Optical Properties of Crater Lake | Water temperature, water chemistry, and optical properties of Crater Lake were studied from 1983 to 1991. In winter and spring, wind energy and convection mixed the water column to a depth of 200 to 250 m. The lake was thermally stratified in summer and early fall; however, the epilimnion was only 5 to 20 m thick, and most of the 589 m deep water column was a cold hypolimnion. The lake was slightly basic, with moderate alkalinity and conductivity. The water column was oxygenated, although slight decreases in dissolved oxygen concentration were noticed near the lake bottom in late summer and early fall. Phosphorus and nitrogen concentrations were low. Orthophosphorus-P concentrations increased slightly with increased lake depth, whereas nitrate-N was below detection limits in the upper 200 m of the water column and then increased with increased lake depth. Secchi disk clarity typically varied from the high-20-m to low-30-m range. The depth of 1 % surface incident light (425-655 nm) in July and August typically ranged between 80 and 100 m. The results also indicated that water temperature, water chemistry, and optical properties of the lake between 1983 and 1991 were consistent with those observed between 1896 and 1982. |
| Development of a 10-year Limnological Study of Crater Lake, Crater Lake National Park, Oregon, USA | Gary L. Larson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 2 | 1996 | 221 - 229 | Development of a 10-year Limnological Study of Crater Lake, Crater Lake National Park, Oregon, USA | This paper summarizes the development of a limnological study of Crater Lake conducted between 1983 and 1992. The program was mandated by Congress in the fall of 1982 after a panel of limnologists found the lake data base (1896-1981) to be inadequate to determine if the phytoplankton community had changed and if the lake was decreasing in clarity as suggested from independent studies between 1978 and 1981. Congress authorized and directed the Secretary of the Interior to promptly instigate studies and investigations as to the status and trends of changes of water quality and to immediately implement such actions as necessary to assure the retention of the lake's natural pristine water quality. Program goals were to develop a detailed data base and an understanding of physical, chemical, and biological characteristics and processes of the lake. Ecological relationships among trophic levels and environmental conditions were stressed to evaluate the hypothesis that the lake had changed in water quality and clarity. |
| Taxonomic Structure and Productivity of Phytoplankton Assemblages in Crater Lake, Oregon | C. David McIntire; Gary L. Larson; Robert E. Truitt; Mary K. Debacon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 2 | 1996 | 259 - 280 | Taxonomic Structure and Productivity of Phytoplankton Assemblages in Crater Lake, Oregon | Interactions among physical, chemical, and biological components and processes in Crater Lake result in a complex and dynamic ecosystem. In winter and spring, wind energy mixes the lake to a depth of about 200 m. During this period, episodic sinking of cold water below the depth of 200 m produces an upwelling of nutrient-rich water from the deep lake, a process that has a strong influence on the concentrations of nutrients available to phytoplankton in the euphotic zone. Patterns of upwelling are variable from year to year, and physical data indicate that water from the deep lake is completely mixed with surface water every 1-4 years. Phytoplankton cell biovolume and total chlorophyll are distributed uniformly to the depth of 200 m in winter and spring, at which time maximum rates of primary production occur in the upper 60 m of the water column. The onset of thermal stratification in July is associated with development of a chlorophyll maximum at depths between 100 and 140 m and a downward shift of the primary production maximum to depths between 60 and 100 m. Thermal stratification also is accompanied by a stratified distribution of phytoplankton populations that is characterized by assemblages with low species diversity and high dominance in the epilimnion and assemblages with higher diversity and lower dominance in the metalimnion and upper hypolimnion. Therefore, the thermal properties of the upper 200 m of Crater Lake, and associated changes in light and nutrients with increasing depth, are closely related to structural and functional attributes of phytoplankton assemblages in the water column. |
| Paleolimnology of Onondaga Lake: the History of Anthropogenic Impacts on Water Quality | H. Chandler Rowell | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 35 - 45 | Paleolimnology of Onondaga Lake: the History of Anthropogenic Impacts on Water Quality | New York State's Onondaga Lake is a polluted, hypereutrophic, saline lake with a remarkable paleolimnological record. The chemical and diatom stratigraphy of two sediment cores was used to document past anthropogenic impacts on the lake's water quality. Onondaga Lake's pre-historic and pre-industrial water quality conditions are clarified and subsequent major pollution events identified. Pre-1800s Onondaga Lake was mesotrophic and considerably less saline (around 230 mgL-1 Cl-) than at present (around 450 mgL-1 Cl-). Factors that most affected lake water quality were: 1) increasing settlement in the watershed which increased lake sedimentation and nutrient levels, 2) development of the salt industry during the 1800s which contributed to a rise in lake salinity, 3) the soda-ash industry in die late 1800s through 1900s which added major amounts of CaCO3 and salt to the lake, and 4) post-World War II urban and industrial development which contributed to very high nutrient, Hg, and other heavy metal loadings. |
| An Optics Model for Onondaga Lake | Steven W. Effler; MaryGail Perkins | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 115 - 125 | An Optics Model for Onondaga Lake | A deterministic optics model for predicting measures of light penetration, including Secchi disc transparency (or clarity; SD) and the vertical attenuation coefficient for downward irradiance (Kd), from concentrations of various attenuating substances, is developed, calibrated, and applied for culturally eutrophic Onondaga Lake, NY. The model is an invaluable management tool for establishing the appropriate focus and realistic expectations for improving clarity in the lake. The model is consistent with optical theory, partitioning attenuation according to the processes of absorption and scattering, and materials contributing to these processes. The model is developed from optical measurements made for the lake over the 1987-1990 interval, reported by Perkins and Effler (1996), and attendant estimates of the values of absorption and scattering coefficients presented herein. It is demonstrated that the primary components responsible for low SD and high Kd in the lake are phytoplankton and tripton (other than CaCO3 particles). Gelbstoff and CaCO3 particles are relatively unimportant. Management efforts to improve clarity should focus on the lake's cultural eutrophication problem. Terrigenous particle inputs received during runoff events would continue to substantially reduce clarity for brief periods if they are not abated. |
| Domestic Waste Inputs of Nitrogen and Phosphorus to Onondaga Lake, and Water Quality Implications | Steven W. Effler; Carol M. Brooks; Keith A. Whitehead | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 127 - 140 | Domestic Waste Inputs of Nitrogen and Phosphorus to Onondaga Lake, and Water Quality Implications | The recent history of loading of total phosphorus (TP) and nitrogen (N) species to Onondaga Lake, NY, from an adjoining domestic waste treatment facility (METRO), and related impacts on die lake, are documented. The discharge from METRO represents an extraordinary contribution to the inflow of the lake; e.g., in most years it is the largest source of water during the month of August. Approximately a 20-fold reduction in effluent TP concentration has been achieved by METRO over die 1970-1993 period, in response to a detergent ban and increased levels of treatment. The TP loading from the facility decreased about 5-fold over the 1977-1992 interval. A significant level of nitrification has been achieved during die warmer mondis since the late 1980s, but this has been attended by increased effluent concentrations of nitrite (NO-2). METRO presently contributes approximately 60, 90, and 80% of the total external loads of TP, ammonia, and total N, respectively. The extremely high prevailing external total loads of TP and total N, approximately 8 and 200 g/m2/y, respectively, severely impact die lake. Recurring degradations associated with the cultural eutrophication of the lake include excessive concentrations of phytoplankton, poor clarity, rapid loss of oxygen from die hypolimnion, and lake-wide oxygen depletion during die fall mixing period. Related water quality standards for transparency and oxygen are violated. A state guidance value for summer epilimnetic TP concentration of 20 μg/L is exceeded by a factor of ≥ 3 annually. Standards to protect aquatic life against the toxic effects of free ammonia and NO-2 are violated by a large margin routinely in die upper waters in summer. METRO is die appropriate focus for related remediation efforts. |
| Development and Testing of a Total Phosphorus Model for Onondaga Lake | S. M. Doerr; R. P. Canale; S. W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 141 - 150 | Development and Testing of a Total Phosphorus Model for Onondaga Lake | Adynamic two-layer mass balance model for total phosphorus (TP) is developed for culturally eutrophic Onondaga Lake, NY, and tested for the May 1987 through 1990 period. The model accommodates key processes in the lake's phosphorus cycle, including settling of the particulate fraction of TP, sediment release, and vertical mass transport Model development and testing were supported by a comprehensive program of field and laboratory measurements and experiments, to determine model coefficients and external loads, and to establish temporal and vertical distributions of lake TP concentrations. The model performs well in tracking documented interannual, seasonal, and vertical distributions of TP in the lake, and thus is appropriate as a management tool to evaluate management scenarios aimed at abating the lake's cultural eutrophication problem. |
| Water Quality Model Evaluations For Scenarios Of Loading Reductions And Diversion Of Domestic Waste Effluent Around Onondaga Lake | Steven W. Effler; Susan M. Doerr | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 181 - 193 | Water Quality Model Evaluations For Scenarios Of Loading Reductions And Diversion Of Domestic Waste Effluent Around Onondaga Lake | Management models for total phosphorus (TP), various nitrogen (N) species, and dissolved oxygen (DO), for polluted culturally eutrophic Onondaga Lake are developed from models presented and tested earlier in this issue (Doerr et al. 1996a, Canale et al. 1996, Gelda and Auer 1996). The management models are applied to test a wide range of remediation alternatives, corresponding to a wide range of reductions in pollutant loading. The analysis focuses primarily on the effluent (3.5 m3/s(80 MGD)) received from an adjoining domestic wastewater plant (METRO), though a reasonable upper bound of reductions in tributary TP load also is considered. The decreases in lake TP and total ammonia (T-NH3) concentrations that could be achieved by partial diversion of METRO, increased treatment at METRO, and reductions in tributary loading, would not be adequate to meet the established in-lake TP goal of 20 μg/L (as a summer average in the upper waters), the T-NH3 standard for the lake (0.77 mgN/L for the upper waters in summer), nor the DO standard for the lake's upper waters (daily average ≥5 mg/L). Diversion of the entire METRO discharge around the lake is found to be necessary to meet the T-NH3 standard, to approach or meet the TP concentration goal, and to avoid violation of the DO standard in the upper waters during fall. Reductions in the prevailing tributary TP load, of as much as 30%, may be necessary to reach the TP goal. |
| Development and Testing of a Dissolved Oxygen Model for a Hypereutrophic Lake | Rakesh K. Gelda; Martin T. Auer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 165 - 179 | Development and Testing of a Dissolved Oxygen Model for a Hypereutrophic Lake | A mechanistic, two-layer mass balance model for dissolved oxygen (DO) in Onondaga Lake, a hypereutrophic, urban system, has been developed and tested. The model accommodates the processes of reaeration, algal photosynthesis and respiration, carbonaceous biochemical oxygen demand (CBOD), nitrogenous biochemical oxygen demand (NBOD), sediment oxygen demand (SOD) and water column oxidation of reduced species. Most model inputs, and many of the kinetic coefficients, were developed through a program of field monitoring and field and laboratory experimentation. The model was calibrated and verified using data collected in 1989 and 1990, respectively. Severe dissolved oxygen depletion is observed in the hypolimnion (lower mixed layer; LML) of Onondaga Lake during summer stratification. SOD and water column oxidation of reduced species diffusing from the sediment are together responsible for >70% of the summer depletion; CBOD, NBOD and algal respiration account for the balance. DO depletion occurs in the epilimnion (upper mixed layer; UML) in the fall. Oxidation of reduced species entrained from the LML is responsible for about 30% of the fall depletion, with algal respiration and mass transport to the LML accounting for about 25% each; CBOD and NBOD are minor sinks. Beyond those features of pollutant loading, fate, and transport, sensitivity analyses suggest mat meteorological conditions importantly influence the character of the DO resources of the lake. |
| Development and Testing of a Nitrogen Model for Onondaga Lake | R. P. Canale; R. Gelda; S. W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 151 - 164 | Development and Testing of a Nitrogen Model for Onondaga Lake | A dynamic two-layer mass balance model for total nitrogen (N) and various species of N is developed and tested for Onondaga Lake, NY, a system in which high concentrations of total ammonia (T-NH3) prevail. The model simulates concentrations of T-NH3, nitrate plus nitrite, particulate organic N (PON), dissolved organic N, total Kjeldahl N, and total N. Processes of the N cycle accommodated include net phytoplankton growth, nitrification, denitrification, ammonification, decay of PON, volatilization of free ammonia, sediment release of T-NH3, settling of PON, and vertical mixing-based exchange between the layers. Model testing is supported by a comprehensive monitoring database of lake concentrations of the N species, and tributary and waste discharge concentrations for calculation of loads. Model credibility is enhanced by the independent determination of several important model coefficients based on field and laboratory experiments, which greatly reduces the role of calibration. Model verification is established by the successful simulation of the distinctly different distributions of various N species documented for the lake in 1989 and 1990. The model is particularly successful in simulating T-NH3 concentrations in the upper waters, and is thus appropriate to evaluate various related remediation strategies for the lake. |
| Phosphorus Pools, Alkaline Phosphatase Activity, and Phosphorus Limitation in Hypereutrophic Onondaga Lake | Susan D. Connors; Martin T. Auer; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 47 - 57 | Phosphorus Pools, Alkaline Phosphatase Activity, and Phosphorus Limitation in Hypereutrophic Onondaga Lake | We examined seasonality in the phosphorus (P) physiology of the phytoplankton assemblage of culturally hypereutrophic Onondaga Lake, an urban system located in metropolitan Syracuse, NY. Four years of monitoring data for ambient dissolved and cellular phosphorus pools and phytoplankton biomass and one year of alkaline phosphatase activity (APA) assays supported the assessment. Kinetic approaches utilizing ambient dissolved and stored nutrient pools were evaluated for their utility in tracking nutrient limitation and gave evidence for luxury uptake of soluble reactive P (SRP) and utilization of the dissolved organic P (DOP) pool by the lake's phytoplankton. The high concentrations of phytoplankton biomass maintained annually from mid-to late summer were sustained in part by the DOP pool. Concentrations of SRP appear to be an inadequate representation of nutrient limitation in the lake. The cellular concentration of P, represented by the cell quota (Q, μg particulate P /μg chlorophyll), was generally lower when SRP was depleted. APA is a sensitive indicator of the utilization of DOP and the occurrence of nutrient limitation. The threshold Q value for inducement of APA in the lake is about 1 μgPPμgChl-1. The onset of APA can be used to identify conditions of resource limitation where further reductions in nutrient availability may be expected to yield proportional improvements in water quality. A kinetic framework that relates growth rate to cellular nutrient concentration (Droop kinetics) is favored over one based on ambient dissolved nutrient concentrations (Monod kinetics) for quantifying nutrient limitation in Onondaga Lake. |
| Forecasting Impacts of a Hypolimnetic Wastewater Discharge on Lake Water Quality | S. M. Doerr; S. W. Effler; E. M. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 207 - 217 | Forecasting Impacts of a Hypolimnetic Wastewater Discharge on Lake Water Quality | Water quality impacts of shifting the shoreline discharge of a major (3.5m3/s) domestic wastewater treatment faclity (METRO) on polluted, eutrophic Onondaga Lake, NY, to a deep-water location are evaluated with three mechanistic water quality models. Transport and mixing inputs for the simulations are specified from the output of a separate hydrothermal model (Owens and Effler 1996). Model simulations indicate, that by trapping enriched effluent in the lower layers, summertime concentrations of total phosphorus (TP) and total ammonia (T-NH3) would decrease in the upper mixed layer (0 to 4.5 m depth interval). Further reductions in the concentrations of those constituents would be realized by reducing sediment release, through maintenance of oxia in the hypolimnion. However, the decreases that could be achieved with the prevailing METRO effluent characteristics would not result in substantial reductions in phytoplankton growth nor prevent violation of the T-NH3 standard. An extremely high degree of nitrification would be needed at METRO, particularly during the late fall to early spring interval (e.g., T-NH3, concentrations < 3.6 mgN/L in effluent), to avoid violation of the T-NH3 standard. Oxygen concentrations in the existing METRO effluent would have to be maintained at approximately 70 mg/L to ensure the hypolimnion remains oxic. To provide oxygen concentrations ≥5 mg/L in the hypolimnion, oxygen concentrations of = 130 mg/L would have to be maintained in METRO's effluent. |
| Modeling the Impacts of a Proposed Hypolimnetic Wastewater Discharge on Stratification and Mixing in Onondaga Lake | Emmet M. Owens; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 195 - 206 | Modeling the Impacts of a Proposed Hypolimnetic Wastewater Discharge on Stratification and Mixing in Onondaga Lake | A one-dimensional hydrothermal model is used to forecast the impact of a proposed hypolimnetic discharge of treated municipal wastewater on stratification and mixing in Onondaga Lake, NY. Important simulated impacts are increased temperatures in the hypolimnion, reductions in density stratification, increased mixing and homogeneity within the hypolimnion, and reductions in the duration of summer stratification. Predictions from this analysis serve as input to water quality models that simulate related impacts of this management action. Features of the hydrothermal model include simulation of entrainment associated with plunging inflows, capability for simulations during ice cover, and a submodel to simulate the near-field mixing associated with a multiport diffuser. The model successfully simulated six consecutive years of historical stratification conditions. The model performs well in simulating the dimensions and temperatures of layers, and the timing/duration of stratification. The model is less successful in simulating the more subtle effects of dense saline inflows that linger from a recently closed soda ash/chlor-alkali facility, such as intermittent formation of chemical stratification during spring and fall mixing. |
| Ionic Inputs To Onondaga Lake: Origins, Character, and Changes | S. W. Effler; M. G. Perkins; K. A. Whitehead; E. A. Romanowicz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 15 - 23 | Ionic Inputs To Onondaga Lake: Origins, Character, and Changes | The origins and loadings of Cl-, Na+, and Ca2+ to ionically polluted Onondaga Lake, NY, are determined based on monitoring data collected for surface inflows over the 1973-1993 interval. The analysis delineates for lake managers the central role a chemical company has played in the loading of these constituents to the lake and the resulting ionic enrichment of the lake. The recurring, but disparate, ratios of Cl-, Na+, and Ca2+ concentrations maintained in the two largest tributaries to the lake depict contrasting industrial and geologic origins of these constituents. Concentrations of the three ionic species are inversely related to flow in these tributaries. The average annual combined loading of Cl-, Na+, and Ca2+ to the lake over the last 12y of operation of the chemical plant was 1.2 million metric tons. The plant closed in 1986, and by 1989 the annual loads of Cl-, Na+, and Ca2+ had decreased by about 79, 67, and 70% respectively. The residual annual input of the ionic waste in 1989, from the area of the most recently abandoned waste beds, was about 12% of the pre-closure load. |
| Density Stratification in Onondaga Lake: 1968–1994 | Steven W. Effler; Emmet M. Owens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 25 - 33 | Density Stratification in Onondaga Lake: 1968-1994 | The profound impact of ionic (saline) waste from soda ash production on the density of inflows to, and the stratification regime of, Onondaga Lake, NY is documented. The analysis is based on inflow data reported by Effler et al. 1996 in this issue and on lake monitoring data collected over the 1968-1994 interval. Particular emphasis is placed on characterization of changes that followed closure of the soda ash manufacturing facility. Inflows enriched with the ionic waste have been more dense than the lake surface and entered as underflows, sometimes plunging to the lake bottom. Density differences have been reduced, but not eliminated, following closure of the facility. During the operation of the facility, the lake annually had a significant salinity component of density stratification, spring turnover failed to occur in a number of years, the duration of summer stratification was extended, and reformation of salinity-based stratification in fall was common. A nearly 90% reduction in ionic waste loading from soda ash production has substantially ameliorated these impacts, though some impact continues to be observed from the residual loading. The impacts of ionic waste on the lake's stratification regime have exacerbated the lake's problem of limited hypolimnetic oxygen resources. |
| Changes in the Zooplankton of Onondaga Lake: Causes and Implications | Clifford Siegfried; Nancy A. Auer; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 59 - 71 | Changes in the Zooplankton of Onondaga Lake: Causes and Implications | The zooplankton assemblage of ionically polluted, culturally eutrophic Onondaga Lake was monitored over the 1979-1989 interval, and compared to surveys conducted in 1968 and 1978. A major shift in the assemblage was apparent by 1987, soon after the closure (1986) of an industrial discharger of ionic (Cl; Na+ and Ca2+) waste. Species richness increased from 8 to 18 common species, and more efficient grazers, large-bodied cladocera and the calanoid copepod Diaptomus sitihides, became dominants. Until 1987, a single cyclopoid copepod, Cyclops vernalis, was the dominant component of zooplankton biomass. The most likely cause for the shift in the zooplankton assemblage of the lake is the reduction in salinity, and attendant precipitation of calcium carbonate, associated with the closure of the industry. Improved clarity in the lake, manifested largely as intervals of dramatic increases described as 'clearing events', observed annually since 1987, has been attributed to die shift to more efficient grazers. The increased grazing pressure, particularly from large daphnids, may also be responsible for the return of late summer nuisance blooms of filamentous cyanobacteria, not observed in the lake since the early 1970s. |
| Onondaga Lake, New York: Legacy of Pollution | S. W. Effler; R. D. Hennigan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 1-12 | Onondaga Lake, New York: Legacy of Pollution | Onondaga Lake, NY, has been described as the most polluted lake in the United States. This medium size (surface area of 12 km2 and mean depth of 10.9 m), rapidly flushed (average of 3.9 flushes/y), urban lake has received large quantities of domestic and industrial waste associated with development of the Syracuse area. Selected features of the history of development of the area, including municipal and industrial inputs to the lake, are reviewed. Presently about 20% of the inflow to die lake is municipal wastewater effluent Standards for dissolved oxygen, fecal coliform, free ammonia, nitrite, clarity, and mercury concentration in fish flesh are violated routinely in the lake, a state guidance value for total phosphorus concentration is exceeded annually, and the lake's stratification/mixing regime and littoral zone have been impacted. Enforcement actions, now underway against die primary sources of municipal and industrial waste, are described. The design of die research program for die lake is reviewed, and the role subsequent articles in this issue play in developing a management strategy for remediation is described. |
| Summer Methane Fluxes and Fall Oxygen Resources of Onondaga Lake | Jeffrey M. Addess; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 91 - 101 | Summer Methane Fluxes and Fall Oxygen Resources of Onondaga Lake | The sediment release and cycling of CH4 in SO2-4 - rich hypereutrophic Onondaga Lake, New York, was assessed for the summer/fall interval of 1989 through a program of collection and analysis of ebullitive gas and monitoring of the lake's water column for dissolved CH4. Approximately 1107 mol of CH4 were released from the lake's sediments, at an average rate of 16 mmol/m2/d, from mid-June to mid-September; two-thirds was dissolved, one-third was in the gas phase. About 75% of the ebullitive release of CH4, or 25% of the total release, was lost from the lake to the atmosphere. Strong temporal variations in ebullitive flux were observed. Oxidation of entrained hypolimnetic accumulations of CH4 contributed importantly to the major depletion of O2 and highly undersaturated conditions observed for the lake's upper layers during the fall mixing period. This water quality problem is a manifestation of the cultural eutrophication of the lake. |
| Optical Characteristics of Onondaga Lake: 1968–1990 | MaryGail Perkins; Steven W. Effler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 103 - 113 | Optical Characteristics of Onondaga Lake: 1968-1990 | We analyzed measurements of light penetration, the angular distribution of irradiance, the spectral quality of light attenuation, chlorophyll, gelbstoff, and turbidity to depict seasonal dynamics and long-term trends in these optical characteristics for eutrophic Onondaga Lake, NY, over the 1968-1990 period. Strong seasonality in optical characteristics has been common in the lake, particularly since the closure of an adjoining soda ash/chlor-alkali manufacturing facility, associated with the dynamics of phytoplankton biomass, inputs of terrigenous particles, and probably zooplankton grazing. The New York State requirement for Secchi disc depth (SD) (1.2 m) was only met for about 20% of the observations before the closure of the soda ash/chlor-alkali facility in 1986. Since closure, there has been a shift to increased light penetration as a result of reductions in the concentrations of attenuating particles. About 65% of SD observations since the closure have met the SD standard. Blue color is not a realistic management goal for Onondaga Lake because of the high gelbstoff concentrations, that are apparently regulated by natural terrigenous inputs. |
| The Aquatic Macrophyte Community of Onondaga Lake: Field Survey and Plant Growth Bioassays of Lake Sediments | John D. Madsen; Jay A. Bloomfield; James W. Sutherland; Lawrence W. Eichler; Charles W. Boylen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 73 - 79 | The Aquatic Macrophyte Community of Onondaga Lake: Field Survey and Plant Growth Bioassays of Lake Sediments | Onondaga Lake, located in the Syracuse metropolitan area of upstate New York, has been heavily impacted by domestic and industrial waste effluents, resulting in a lake with high salinity, low light availability, and a highly calcareous, nutrient-poor sediment. These factors appear interrelated in reducing the cover, distribution and diversity of aquatic plants between 1940 and 1990. A quantitative survey in 1991 found that only 13% of the littoral zone had any aquatic plants. The plant community was dominated by Potamogeton pectinatus (11%), with four other submersed aquatic plants found: Ceratophyllum demersum, Heteranihera dubia, Myriophyllum spicatum, and Potamogeton crispus. Aquatic plants were found less often than expected on the calcium-carbonate oncolite sediments, which are formed from precipitated calcium carbonate, compared to other sediment types in the lake. Laboratory studies were developed to evaluate the role of sediments in limiting plant growth. These studies showed that Onondaga Lake sediments supported less growth than a reference sediment, but no differences among Onondaga Lake sediment types (oncolite, silt, sand or organic) were found in plant growth bioassay studies. |
| The Role of Pollution and External Refugia in Structuring the Onondaga Lake Fish Community | Peter J. Tango; Neil H. Ringler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 12 | 1 | 1996 | 81 - 90 | The Role of Pollution and External Refugia in Structuring the Onondaga Lake Fish Community | Historical accounts of Onondaga Lake dating to the 1600's indicate that the lake once supported a coldwater fishery. By the late 1800's, severe degradation of the lake and adjacent tributary environments was accompanied by declines in the American eel (Anguilla rostrata), and extirpation of Atlantic salmon (Salmo salar) and whitefish (Coregonus sp.). Nine faunal surveys were conducted from 1927 to 1994. We used rarefaction analyses to standardize survey results by computing expected species richness values (E(Sm)) relative to the 1946 gill net catch (7 species, m=164 individuals). Linear regression applied to the expected richness values (E (S164)) over time showed a significant increase in richness from 1946 (YEAR=0) to 1994 (YEAR=47) for fish caught in gill nets [E(S164) = 0.153*YEAR + 6.785, r2=0.79, P<0.005] and trap nets [E(S164) = 0.226*YEAR + 3.723, r2=0.89, P<0.01]. Although species richness has increased, almost half of the species captured since 1989 show no evidence of juvenile recruitment from within the lake. This result points to the role of immigration in maintaining lakewide diversity. The present community structure has developed from 1) species specific declines and extirpations, 2) invasion and establishment of pollution tolerant species, and 3) fishes interacting with refugia. |
| Historical Ecology of a Hypereutrophic Florida Lake | Mark Brenner; Thomas J. Whitmore; Jason H. Curtis; Claire L. Schelske | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 3 | 1995 | 255 - 271 | Historical Ecology of a Hypereutrophic Florida Lake | Lake Hollingsworth lies in phosphate-rich central Florida. Recent limnological data show the lake has been hypereutrophic for >25 years, but nothing was known of the lake's trophic history prior to the late 1960s. A paleolimnological study was undertaken to: 1) evaluate the distribution of organic sediments in the basin, 2) reconstruct historical water quality to determine whether the lake is naturally (edaphically) or anthropogenically nutrient-rich, and 3) assess the feasibility of reducing in-lake nutrient concentrations. Organic sediments are distributed rather uniformly above the sandy substrate. Two 210Pb-dated sediment cores taken ≈0.7 km apart display similar stratigraphies with respect to density, organic matter, total C, N, P, radioisotopes, biogenic SiO2, diatoms and δ13C in organic matter. Limnetic Ptot reconstructions, inferred from diatoms, show eutrophic (≈30 μg L-1) conditions in the late 1800s. Total P increased after 1920 and very high Ptot concentrations (125 to >200 μg L-1) are inferred for the 1950s through 1970s. Cultural eutrophication was probably a consequence of agriculture, residential development, construction of Florida Southern College, road building, stormwater runoff and regional phosphate mining. Total P inferences in the 1980s declined to ≈65 μg L-1, reflecting soil stabilization and reduced mining activity. The historical perspective provided by paleolimnological data demonstrates that Lake Hollingsworth was naturally eutrophic, but became hypereutrophic as a consequence of anthropogenic nutrient loading. It is probably not feasible to reduce in-lake nutrient concentrations significantly in this shallow, urbanized, hypereutrophic waterbody. |
| Gradient Changes in Water Quality During Low Flows in Run-of-the-River and Reservoir Impoundments, Lower Snake River, Idaho | Dewey F. Worth | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 3 | 1995 | 217 - 224 | Gradient Changes in Water Quality During Low Flows in Run-of-the-River and Reservoir Impoundments, Lower Snake River, Idaho | A synoptic study of water quality within run-of-the river and two reservoir impoundments (Brownlee Reservoir and Swan Falls Reservoir) was conducted in southwest Idaho. Results indicated that gradient differences in nitrogen, total solids concentrations and chlorophyll a were related to variations in mainstem flow volume and contributions of external sources. The large influx of organic loading and nutrients to a downstream reservoir was accompanied by depletion of oxygen levels and produced strong longitudinal gradients of water quality within the reservoir. Results were consistent with other studies of large linear reservoirs dominated by advection processes. |
| Water Quality Dynamics in the Discharge of a Southeastern Hydropower Reservoir: Response to Peaking Generation Operation | Steven L. Ashby; Robert H. Kennedy; William E. Jabour | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 3 | 1995 | 209 - 215 | Water Quality Dynamics in the Discharge of a Southeastern Hydropower Reservoir: Response to Peaking Generation Operation | Sampling was conducted to determine the distribution and fate of physicochemical constituents in the releases from West Point Dam, a hydropower project located in west-central Georgia. Routine operation of the dam resulted in two distinct release regimes; peaking operation with meta- or hypolimnetic withdrawal and low-flow operation with near-surface withdrawal. Differences in release water quality were associated with stratified conditions in the reservoir forebay and changes in release regime. Temperatures were most responsive to diel conditions and dissolved oxygen concentrations varied with release type. Concentrations of total iron and manganese in die tailwater, which ranged from 0.3 to 1.9 and 0.1 to 0.5 mg/L-1, respectively, were influenced by hydrograph dynamics, downstream tributary inflows, and physicochemical processes. Longitudinal gradients were observed as increases in dissolved oxygen concentrations and decreases in metals concentrations during steady-state conditions. Processes leading to losses of iron and manganese included oxidation, adsorption, and sedimentation. |
| Widespread Oxygen Bubbles To Improve Reservoir Releases | Mark H. Mobley; W. Gary Brock | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 3 | 1995 | 231 - 234 | Widespread Oxygen Bubbles To Improve Reservoir Releases | This paper describes the installation and testing of an oxygen diffuser system in the forebay of TVA's Douglas Dam. The diffuser system is made up of plastic pipe frames and porous hoses that spread very small oxygen bubbles over a large area near the bottom of die reservoir. Operation of the system has demonstrated very high oxygen transfer efficiencies and a capacity to increase die hydropower discharge by 3 mg L-1 of dissolved oxygen. |
| Aerating Weirs For Environmental Enhancement of Hydropower Tailwaters | Gary E. Hauser; W. Gary Brock | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 3 | 1995 | 225 - 229 | Aerating Weirs For Environmental Enhancement of Hydropower Tailwaters | Aerating weirs were used to enhance dissolved oxygen during hydropower generation and to enhance minimum flow between periods of generation. Two different types of weirs (labyrinth and infuser) were designed, constructed, and field tested for performance. The labyrinth is characterized by an extended crest length with a “W†shape in plan view, while the infuser is acting as a broadcrest weir with flow through it. In plan view, the infuser is more compact in the channel, with the appearance of a broadcrest weir. Both exhibited excellent aeration characteristics in performance testing, achieving 55 percent to 70 percent aeration efficiency, where aeration efficiency is defined as a fraction of the oxygen deficit removed by weir aeration. The labyrinth exhibited somewhat more aeration per unit drop height than the infuser. In terms of economy of construction, the infuser appears more favorable in situations of high river specific discharge (>1.9 m2 s-1), while the labyrinth is more favorable in low river flow situations (<0.9 m2 s-1). In the intermediate range, economics of both are comparable, and other site-specific factors are required to assess the best choice. |
| Surficial Distribution of Chemical Constituents in Accumulated Reservoir Sediments in Relation to Observed Water Quality Patterns | Steven L. Ashby; James E. Schindler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 3 | 1995 | 235 - 244 | Surficial Distribution of Chemical Constituents in Accumulated Reservoir Sediments in Relation to Observed Water Quality Patterns | Surficial sediments from the main stem of a reservoir were examined to determine the distribution of selected chemical constituents in accumulation zones. Accumulated sediments were apparent along a longitudinal axis, coincident with maximum depth, for approximately 54 km of the 63 km long reservoir. Within this zone, concentrations of total phosphorus, nitrogen, and iron were observed to increase from the headwater region to the dam. Concentrations of total phosphorus, nitrogen, iron, and total organic carbon were also significantly correlated, (p < 0.05). Total manganese concentrations were variable and longitudinal gradients were not observed. Water quality patterns observed for the reservoir included seasonal hypolimnetic anoxia, increased solubilization of sedimentary manganese in the downstream region, and longitudinal gradients in selected water quality constituents. Comparisons of surficial distribution patterns in accumulated sediments to water quality patterns suggest sediment quality in accumulation zones is impacted by internal distribution mechanisms, reservoir operations, and basin hydrology. |
| Internal Phosphorus Loading in Shallow Lakes: Importance and Control | Eugene B. Welch; G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 3 | 1995 | 273 - 281 | Internal Phosphorus Loading in Shallow Lakes: Importance and Control | Decreasing the algal biomass and increasing transparency in shallow, unstratified lakes is usually more difficult than for deep, stratified lakes. Eutrophic unstratified lakes (or shallow, stratified lakes susceptible to metalimnion erosion) have typically responded slowly to reduced external nutrient loading, usually because of longevity of internal loading. That is because sediment-released nutrients (especially phosphorus) readily enter the trophogenic zone of shallow lakes during the growing season and result in high lake concentrations. In stratified lakes, metalimnia may serve as barriers to phosphorus transport into the trophogenic zone. Although the whole water column in shallow lakes is usually aerobic, several mechanisms can combine to produce relatively high sediment phosphorus release rates in these lakes. These include: 1) wind resuspension and bioturbation, combined with high pH or low Fe/P ratio that maintains high P solubility, 2) periodic anoxia and reducing conditions promoted by calm, warm weather, and 3) macrophyte senescence. Attempts to reduce algal biomass by controlling internal phosphorus loading have often been effective. |
| The Effect of Pump-Storage Power Generation on Water Column Optical Features and Plankton Dynamics in the Forebay of Richard B. Russell Reservoir | J. E. Schindler; B. J. Speziale; S. P. Mellichamp; E. E. Robertson; J. J. Hains | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 3 | 1995 | 245 - 253 | The Effect of Pump-Storage Power Generation on Water Column Optical Features and Plankton Dynamics in the Forebay of Richard B. Russell Reservoir | Optical properties and phytoplankton ecology appear to be altered by pump-storage power generation in Richard B. Russell Reservoir, the newest impoundment on the Savannah River on die South Carolina-Georgia border. Downwelling vertical attenuation and spectral attenuation coefficients increased with pump-storage power testing. Areal productivity values increased with pump-storage activity when compared with control stations and die previous year. Productivity sustained values in excess of 50 mg m2 hr-1 during die summer of 1993 with a shift of die maximum from metalimnetic chlorophyll layers to die surface. However, areal chlorophyll a concentrations decreased during pump-storage testing when compared with the previous year. These data suggest that large-scale mixing caused by pump-storage activities lead to increases in plankton productivity and light attenuation coefficients. However, the unusually hot, dry conditions during the summer of 1993 could also contribute to alterations of optical properties and depths of convective mixing. |
| Zebra Mussel, Dreissena polymorpha: Population Dynamics and Notes on Control Strategies in a Reservoir in Western Greece | Alexis Conides; Theodore Koussouris; Konstantinos Gritzalis; Ilias Bertahas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 4 | 1995 | 329 - 336 | Zebra Mussel, Dreissena polymorpha: Population Dynamics and Notes on Control Strategies in a Reservoir in Western Greece | Growth, mortality and yield were investigated in the zebra mussel, Dreissena polymorpha (PALLAS) from the Kastraki artificial reservoir, Central Greece. Allometric relationships were defined using shell length and total wet weight of the sampled individuals. The parameters of die Gompertz, von Bertalanffy and logistic growth curves (both length and weight) were estimated and gave L∞ = 4.05 cm, K = 0.808 per year, length-at-birth = 39 μg and weight-at-birth = 19 μm. The length-frequency distribution showed 5 distinct modes from which the last 2 (IV and V) are considered the same due to high similarity and therefore, die longevity of the species (tλ) is about 4 years. The natural mortality (M) is considered equal to die total mortality (Z) because die population is commercially unexploited and thus, fishing mortality is 0. The Z was estimated to be about 2.15 according to both die Wetherall method and the length converted catch curve analysis. Control strategies of this population include either the treatment with disinfectants (chlorine) during die reproduction period of die species or the introduction of known predators in the reservoirs. |
| Phosphorus Loading of an Urban Lake by Bird Droppings | Nancy M. Scherer; Harry L. Gibbons; Kevin B. Stoops; Martin Muller | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 4 | 1995 | 317 - 327 | Phosphorus Loading of an Urban Lake by Bird Droppings | The role of birds in nutrient cycling in lakes and reservoirs is often not quantified, or thought to be relatively unimportant. However, when bird populations are large relative to the size or volume of the waterbody, a substantial fraction of the nutrient pool may cycle through birds. In this report, we estimate the mass of phosphorus in bird droppings cycling through Green Lake, a productive lake in urban Seattle, between January 1992 and December 1994. Phosphorus loading from bird droppings is compared to the mass of phosphorus entering the lake from other sources measured during a concurrent limnologic study. Waterbirds spent 528,355 bird-days (the number of bird-use days) at Green Lake in 1992, 530,318 bird-days in 1993, and 546,943 bird-days in 1994. The most abundant bird species at the lake were American coots, mallards, gadwalls, and various species of gulls. Of all birds at Green Lake, waterbirds accounted for greater than 99% of the phosphorus loading. Total phosphorus loading by birds was estimated to be 160 kg P year1 (equivalent to 0.154 g P m-2 year-1) in 1992,159 kg P year1 (equivalent to 0.153 g P m-2 year-1) in 1993, and 167 kg P year1 (equivalent to 0.160 g P m-2 year-1) in 1994. Total phosphorus in bird droppings constituted 27% of the total phosphorus loading to the lake from all sources in 1992, 25% in 1993, and 34% in 1994. Based on the behavior of the birds, their high metabolic rate, and the paucity of forage in the surrounding urban area, we estimate 87% of the phosphorus in bird droppings originated from food items in the lake and represented internal cycling. The mass of phosphorus entering the lake in droppings was not correlated with three indices of water quality and trophic state, lake total phosphorus and chlorophyll a concentrations, or Secchi depth. However, birds may potentially increase the productivity of water bodies by changing the form, rate, and pathways of cycling, and physical compartment of phosphorus. |
| Mortality of Largemouth Bass (Micropterus salmoides) and Steelhead Trout (Oncorhynchus mykiss) in Densely Vegetated Littoral Areas Tested Using in situ Bioassay | Jonathan D. Frodge; David A. Marino; G. B. Pauley; G. L. Thomas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 4 | 1995 | 343 - 358 | Mortality of Largemouth Bass (Micropterus salmoides) and Steelhead Trout (Oncorhynchus mykiss) in Densely Vegetated Littoral Areas Tested Using in situ Bioassay | Concentrations of dissolved oxygen (DO) in dense beds of aquatic macrophytes in two western Washington lakes were routinely measured below reported lethal limits (≤1 mg L-1) for largemouth bass (Micropterus salmoides) and steel head trout (Oncorhynchus mykiss). The impact of the observed low DO concentrations on resident fish was examined both by field observation and by conducting 72 hour in situ cage bioassays. Replicate cages were placed in two Western Washington lakes at the surface, 1 m, and 2 m deep, in dense patches of aquatic macrophytes and open water. No steelhead trout mortalities occurred over 72 hours in the open water or surface water in dense patches of Myriophyllum spicatumia Lake Washington where DO concentrations were consistently > 4.0 mg L-1. No significant mortality of steelhead trout occurred in the surface cages of the floating leaf Nymphaea odorata, but all fish were dead within 12 hr at 1 m, where concentrations of DO were consistently < 4 mg L-1. No significant mortalities of largemouth bass occurred in the open surface water of Keevies Lake, or in the upper 1 m of water in patches of Potamogeton natans where concentrations of DO were consistently > 2 mg L-1. Significant largemouth bass mortalities occurred at both the surface and at 1 m depth in dense beds of the floating leafed macrophyte Brasenia schreberi, and in the bottom water (<2.0 m) of both floating leafed and submersed species, where DO concentrations were < 2 mg mg L-1. The observed lethal DO concentrations and high mortalities in the bioassay tests indicate that at high densities aquatic macrophytes can have significant detrimental localized effects on fish. |
| Removal of Triploid Grass Carp with an Oral Rotenone Bait in Two Central Florida Lakes | Craig T. Mallison; Rue S. Hestand III; Boyd Z. Thompson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 4 | 1995 | 337 - 342 | Removal of Triploid Grass Carp with an Oral Rotenone Bait in Two Central Florida Lakes | Fish Management Bait (FMB), a rotenone-laced feed pellet, was tested in two central Florida lakes to evaluate its effectiveness in removing triploid grass carp (Ctenopharyngodon idella). Initial trials of FMB were successful in removing 251 triploid grass carp (average nine/trial) at Live Oak Lake, 152 ha, and 110 (average five/trial) at Lake Whippoorwill, 132 ha. Retrials (secondary applications of FMB) were much less effective and removed 47 triploid grass carp (average one/trial) at Live Oak Lake and 31 (average one/trial) at Lake Whippoorwill. Effects on non-target fish were minimal (average one fish removed/seven trials) and no wildlife was visibly affected. FMB showed potential as an effective and selective method of triploid grass carp removal. |
| The Effects of Fish Assemblage Composition on Lake Water Quality | Rolando Quirós | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 4 | 1995 | 291 - 298 | The Effects of Fish Assemblage Composition on Lake Water Quality | Current trophic cascade theories predict that changes in the piscivore to planktivore biomass ratio will cascade down the food web, and will cause both chlorophyll and water clarity to deviate from nutrient - predicted values in individual lakes. An extensive survey of mid summer observations for nutrients, phytoplankton, zooplankton, and fish in Argentinean lakes and reservoirs, were used to study the effects of planktivorous and piscivorous fishes on chlorophyll concentrations and Secchi disk transparency. Regression analysis for different subsets of the data was used in this study. Regressions of chlorophyll on total phosphorus and Secchi disk on total phosphorus differed significantly among lakes with different fish assemblages. At comparable total phosphorus concentrations, lakes with planktivores but without piscivores had the highest phytoplankton biomass and the lowest water clarity. In conclusion, the results show that the fish assemblage composition has a dramatic effect on chlorophyll concentrations and water transparency when nutrient effects have been accounted for. |
| A Regression Model for the Prediction of Chlorophyll a in Lake Okeechobee, Florida | E. Conrad Lamon III | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 4 | 1995 | 283 - 290 | A Regression Model for the Prediction of Chlorophyll a in Lake Okeechobee, Florida | Lake Okeechobee water quality data from 1980 to 1993 were used to develop a model for predicting chlorophyll a concentrations. Data collected by the South Florida Water Management District (SFWMD) and the University of Florida included stage, temperature, total nitrogen, total phosphorous, wind velocity and chlorophyll a. The lake was divided into five zones based on previous studies. Exploratory data analyses were performed to determine spatial and temporal scales of variation in chlorophyll a levels. The result of a backward testing strategy based on Type III sum of squares was a linear model in which the principle predictor of chlorophyll a concentration was log10 total phosphorus, followed by log10 total nitrogen and then by log10 temperature, die latter of which can be considered a seasonality term. The model suggests that location in the lake is important in predicting chlorophyll a since statistically different slopes describe the relationship between the predictors (temperature, total phosphorus and total nitrogen) and the response (chlorophyll a) for each zone. Stage is a highly significant term (p < 0.0001), and wind is absent as a predictor in the final model. The high importance given to the interaction terms involving zone suggests that location is a prime determinant of chlorophyll a concentration, perhaps as a surrogate of (unmeasured) individual station (or ZONE) wind effects or fetch length. |
| Changes in Water Chemistry in a Macrophyte-Dominated Lake Before and After Herbicide Treatment | Kim M. O'Dell; Joel VanArman; Barbara H. Welch; Steven D. Hill | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 4 | 1995 | 311 - 316 | Changes in Water Chemistry in a Macrophyte-Dominated Lake Before and After Herbicide Treatment | Lake Istokpoga is the fifth largest freshwater lake in Florida, and is widely renowned for its abundance of sport fish. By 1988, an infestation of the exotic aquatic weed hydrilla, had severely impacted many water related functions on Lake Istokpoga. Beginning in 1988, the lake was treated with fluridone to control hydrilla. Five years (1988-1992) of water chemistry data are presented in this paper, representing pre- (Feb.-Dec. 5, 1988) and post- (Dec. 20, 1988-Dec. 1992) herbicide application periods. Trophic state variables were calculated to characterize lake condition. Reductions in hydrilla populations through herbicide treatments caused increases in total phosphorus and chlorophyll a concentrations, and decreases in Secchi depth. No significant increases in the total nitrogen concentrations were observed between the before and after treatment periods. Fluridone treatment of Lake Istokpoga cost approximately $3.7 million (through 1992), and was only temporarily effective at controlling hydrilla. |
| Zooplankton Trophic State Relationships in Four Alabama–Georgia Reservoirs | Chris D. Harman; David R. Bayne; Mark S. West | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 4 | 1995 | 299 - 309 | Zooplankton Trophic State Relationships in Four Alabama-Georgia Reservoirs | In a 16-month study of four Alabama-Georgia reservoirs, data were collected to relate the trophic condition of the reservoirs to the zooplankton density, biomass, composition, diversity and spatial and temporal distribution within the systems. With the Carlson trophic state index (TSI) and using chlorophyll a concentrations in the calculation, the trophic status of the lakes ranged from a TSI of 39 (mesotrophic) to 65 (highly eutrophic). Total zooplankton density (107 organisms L-1 to 1,590 L-1) and rotifer density (70 L-1 to 1,481 L-1) increased with lake trophy. Crustacean zooplankton density and biomass did not respond as clearly to the trophic gradient During the fall/winter months crustacean zooplankton biomass was greater in the mesotrophic lake than in the three eutrophic lakes. An estimated 36% of the crustacean zooplankton of the mesotrophic lake was greater than 500 urn in total length (TL) compared to a range of 11% to 20% in the three eutrophic lakes. Bosmina longirostris (200 μm to 500 μm TL) and cydopoid copepods were the dominant crustacean zooplankton during the spring in the eutrophic lakes. Holopedium amazonicum (400 μm to 1400 μm TL) was the dominant cladoceran in the spring in the mesotrophic lake and calanoid copepods were present throughout the year. The presence of these two relatively large crustaceans in Lake Martin helped offset the expected increase in crustacean zooplankton biomass with increasing trophic gradient. |
| Abstracts of Presentations | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 2 | 1995 | 113 - 206 | Abstracts of Presentations | |
| Technical Sessions | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 2 | 1995 | 90 - 112 | Technical Sessions | |
| Index to Authors by Session Numbers | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 2 | 1995 | 207 - 208 | Index to Authors by Session Numbers | |
| Establishing a Chlorophyll a Goal for a Run-of-the-river Reservoir | Steven A. Heiskary; William W. Walker Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 1 | 1995 | 67 - 76 | Establishing a Chlorophyll a Goal for a Run-of-the-river Reservoir | Lake Pepin, a 100 km2 run-of-the-river reservoir, is located on the Mississippi River about 80 km downstream of the Twin Cities metropolitan area on the border between Wisconsin and Minnesota. Amajor inter-agency study of Lake Pepin and the Mississippi River has been underway since 1990 for the purposes of determining the impacts of the effluentfrom the Metropolitan Waste Control Commission's Metropolitan Wastewater Treatment Facility on Lake Pepinand to predict the benefits of reducing effluent phosphorus levels to 1 mg L-1 or lower. Severe nuisance algal blooms and fish kills during the low flows of 1988 prompted this study. Understanding the reservoir limnology and factors contributing to user perception of “nuisance algal blooms†(in terms of chlorophyll a concentration or phytoplankton species composition), are important steps in developing a chlorophyll a goal for Lake Pepin. Based upon analyses of chlorophyll a data, phytoplankton composition, and user perception information, a summer mean chlorophyll a concentration of 30 mg m-3 is recommended as a water quality goal for Lake Pepin. Nutrient-mass balance modeling suggests that a dramatic reduction in the inflow phosphorus concentration and in the overall in-lake phosphorus concentration (including internal loading) will be required to achieve this goal during low-flow summers. |
| Evaluation of the Growth of Vallisneria americana Michx. in Relation to Sediment Nutrient Availability | S. J. Rogers; D. G. McFarland; J. W. Barko | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 1 | 1995 | 57 - 66 | Evaluation of the Growth of Vallisneria americana Michx. in Relation to Sediment Nutrient Availability | A recent (1988-1991) decline of Vallisneria americana Michx. (wildcelery) in Lake Onalaska, Wisconsin, prompted coordinated laboratory and field studies to evaluate die capacity of different sediments in die lake to support Vallisneria growth. Two sites were selected that formerly supported Vallisneria beds but differed in hydrologic patterns and sediment characteristics. SedimentfromSitel (die protectedsite) was predominandyfine-textured, with a silt-clay particle fraction of 77 percent; sediment from Site 2 (die unprotected/open water site) contained 79 percent coarse-grained sand. In die laboratory study, production and morphology of Vallisneria were examined on nonamended sediments from each site and on die same sediments amended by additions of N and P. In die field study, Vallisneria tubers were planted at die two sites and harvested after 12 weeks of growth to compare morphology and tissue nutrient concentrations. In order to account for local temperature and light conditions, surface water temperature, Secchi depth, and light attenuation were monitored on a weekly basis. Laboratory study results revealed that increased N availability (by N addition) generally increased total biomass production and plant height, and to a lesser extent, tuber and seed pod production. Additions of P had little overall positive effect on Vallisneria. Where growth was limited, N concentrations in aboveground plant tissues were below die critical N level established for this species. However, in all treatments of die study, aboveground tissue P concentrations were adequate for growth. In die field study, Vallisneria grew well at both sites and apparently was not limited by N or P. The only significant difference in growth between die two study sites was in maximum plant height (greater at site 2), probably a response by Vallisneria to differences in ambient light conditions between die two sites. Marked differences between field and greenhouse study results suggest that growth of Vallisneria on intrinsically infertile sediments may depend on a continuous N supply to die sediments, most likely via sedimentation. Present (1992) conditions in Lake Onalaska are suitable for growth; thus, reestablishment of Vallisneria in the lake is likely, as long as conditions remain unchanged. |
| Plenary Speakers | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 2 | 1995 | 87 - 89 | Plenary Speakers | |
| Control of Residential Stormwater by Natural Buffer Strips | Steven E. Woodard; Chet A. Rock | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 1 | 1995 | 37 - 45 | Control of Residential Stormwater by Natural Buffer Strips | This field study evaluated the effectiveness of natural buffer strips to remove phosphorus and suspended solids from residential stormwater. Four experimental sites and one control site were selected for uniformity of vegetation and parent soil material, with slope being the prime variable. The selected slopes fell into two groups: (1) 1-5% slope; and (2) 10-15% slope. All sites were at least 46 m (150 feet) in length and tested at 8 m (25 ft) intervals so that buffer strip effectiveness could be examined as a function of length. Each experimental buffer strip received elevated inputs of phosphorus and sediment from either a subdivision or a condominium complex. A unique system of in-ground sampling cups was used to collect runoff samples throughout the plots. It was concluded that residential runoff is relatively high in phosphorus and suspended solids, especially during the construction phase of residential developments. The effectiveness of natural buffer strips is highly variable, but in most cases, a 15 m (50 ft) natural buffer was effective in reducing phosphorus concentrations to background values observed at the control site. Ground cover had a more significant impact on pollutant removal than slope. Some areas of exposed soil actually contributed suspended solids to the overland flow. It is anticipated that the results of this study will help guide regulators in properly sizing buffer strips in residential subdivisions. It is recommended that site inspection be incorporated into the sizing process, given the high variability of buffer strip quality between sites. |
| Abiotic and Biotic Factors Related to Black Bass Fishing Quality in Alabama | A. Scott Hendricks; Michael J. Maceina; William C. Reeves | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 1 | 1995 | 47 - 56 | Abiotic and Biotic Factors Related to Black Bass Fishing Quality in Alabama | We used black bass (Micropterus spp.) tournament catch data from 27 Alabama reservoirs collected from 1986 to 1991. These data included nearly 0.5 million angler hours of effort and examined 17 factors possibly related to variation in catch rates and size of black bass caught by anglers. Shoreline length, the shoreline development index, and reservoir surface area were all positively related (r = 0.40 to 0.57; P <0.05) to catch-per-hour of black bass greater than 304 mm total length. Chlorophyll a concentrations, conductivity, reservoir age, and the percent genetic influence of Florida largemouth bass (M. salmoides floridanus) in the largemouth bass population were positive regressors (P < 0.05) of average weight of black bass caught and combined, these variables explained 73% of the variation of this fishery parameter in a multiple regression equation. Similarly, Florida largemouth bass influence, the morphoedaphic index (Ryder 1965), and chlorophyll a were all positive regressors (P < 0.05) of catch rates of memorable-size (≥ 2.27 kg) fish and together, explained 63% of die variation in this term. Our analysis suggested that differences in trophic state ranging from eutrophic to oligo-mesotrophic were not related to catch rates, but were associated with smaller caught fish and greater effort to catch a memorable-size fish. Florida largemouth bass influence, either created through stocking efforts or by natural occurrence, was associated with anglers catching much larger fish, and this was more apparent in eutrophic water bodies. Many reservoir attributes considered in this analysis cannot be directly manipulated to affect black bass fisheries, but recognition of die relations among these variables will assist fishery biologists and limnologists assess die potential for management of black bass fisheries. |
| Using Constructed Wetland-Pond Systems to Treat Agricultural Runoff: A Watershed Perspective | Roy Bouchard; Matthew Higgins; Chet Rock | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 1 | 1995 | 29 - 36 | Using Constructed Wetland-Pond Systems to Treat Agricultural Runoff: A Watershed Perspective | Long and Cross Lakes in the St. John Valley watershed of northern Maine have exhibited chronic algae blooms in past years. Survey data and modeling determined agricultural runoff to be die main source of phosphorus and sediments in both watersheds. “Nutrient/Sediment Control Systems†(NSCS) are being used to treat runoff from target subwatersheds. The systems consist of a sedimentation basin, grass filter strip, wetland, and detention pond in series. Annual removal efficiencies for one system were 85-88% for total phosphorus and 96-97% for total suspended solids. Seasonal removals varied considerably, with spring flows exporting more phosphorus and sediment from the system than was imported. Phosphorus loadings to Long Lake will be reduced between 10-33% with 20 NSCS and diversion of municipal wastewater effluent to a nearby river. |
| Regional Patterns of Total Phosphorus in Lakes of the Northeastern United States | Christina M. Rohm; James M. Omernik; Chris W. Kiilsgaard | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 1 | 1995 | 1-14 | Regional Patterns of Total Phosphorus in Lakes of the Northeastern United States | A map of total phosphorus regions has been compiled for lakes in the glaciated portion of the northeastern United States. Total phosphorus data from over 2,600 of the approximately 22,000 lakes larger than 1 hectare in the study area were used for the analysis. Many of the lake regions delineated include lakes with widely differing phosphorus levels. The distinguishing feature of each region is the distribution, or mosaic, of lake phosphorus values. The pattern of values is determined by, or associated with, the particular landscape characteristics of that region and differs in comparison to patterns of lake phosphorus values in adjacent regions. Characteristics examined included: physiography, land cover/land use, vegetation (both potential and existing), soil type, and bedrock and surficial geology. For some regions, where summer lake phosphorus data were sparse, increased emphasis was placed on using combinations of landscape characteristics to refine boundaries. This method comprised using those characteristics most strongly associated with patterns of summer phosphorus data elsewhere in the region and/or patterns developed and qualitatively adjusted from lakes sampled during other seasons. Accompanying the map are descriptions of the distinctive attributes of each region, the reliability of the data used for analysis, and frequency distributions of known and estimated summer total phosphorus concentrations in lakes. The predictive power of similar regionalizations (Omernik 1987, Omernik et al. 1988) has been evaluated using independent data sets (Larsen et al. 1986, Omernik et al. 1991) and the regionalizations have proven useful for managing lakes in the Midwest (Heiskary et al. 1987, Heiskary and Walker 1988, Fulmer and Cooke 1990, Omernik et al. 1991, Lillie et al. 1993). This regionalization is offered as a framework for further verification and application to lake management decisions and the setting of regionally appropriate goals for attainable water quality in lakes of the northeastern United States. |
| Relating Algal Bloom Frequencies to Phosphorus Concentrations in Lake Okeechobee | William W. Walker Jr.; Karl E. Havens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 1 | 1995 | 77 - 83 | Relating Algal Bloom Frequencies to Phosphorus Concentrations in Lake Okeechobee | Empirical relationships were developed between algal bloom frequencies and total phosphorus concentrations for three distinct regions of Lake Okeechobee, and hypotheses were derived to explain observed spatial variation in those relationships. The analyses were based on water quality monitoring data collected monthly between 1986 and 1993, at 10 open-water stations, 12 north littoral stations, and 14 south littoral stations. Using a cross-tabulation procedure, phosphorus/bloom-frequency relationships were developed for bloom criteria of 10, 20, 30, 40, 50, and 60 μg L-1 chlorophyll a. For bloom criteria in the range of 40 to 60 μg L-1 chlorophyll a, blooms were not detected when phosphorus was less than 30 μg L-1, During the 1986-1993 monitoring period, this threshold phosphorus concentration was exceeded 3% of the time in the open lake, 25% of the time in die north littoral, and 48% of the time in die south littoral. When phosphorus concentrations were between 30 and 60 μg L-1 in die littoral regions, frequency or risk of an algal bloom increased with phosphorus concentration. The maximum risk of an algal bloom generally occurred when phosphorus exceeded 60 μg L-1. This condition was observed 70% of die time in the open lake, 29% of the time in the north littoral, and 15% of the time in die south littoral. When phosphorus concentrations exceeded 60 μg L-1, risk of a 40 μg L-1 bloom was 19% in the open lake, 28% in the north littoral, and 60% in the south littoral. Regional variations in die relationship between phosphorus and bloom frequency may be due to variations in nitrogen availability. Highest total nitrogen concentrations were found in the south littoral zone, where bloom frequencies at a given phosphorus concentration were also highest. Reductions in lake water phosphorus concentrations can be expected to cause reductions in bloom frequencies in die littoral zones, but have little impact on die open lake. This result has positive implications for lake users, because die more responsive littoral region is also the location of die most frequent algal blooms. |
| An Historical Account of Water Quality Changes in Candlewood Lake, Connecticut, Over a Sixty Year Period Using Paleolimnology and Ten Years of Monitoring Data | Laurence J. Marsicano; Jeffrey L. Hartranft; Peter A. Siver; Josephine S. Hamer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 11 | 1 | 1995 | 15 - 28 | An Historical Account of Water Quality Changes in Candlewood Lake, Connecticut, Over a Sixty Year Period Using Paleolimnology and Ten Years of Monitoring Data | A paleolimnological study was used in conjunction with ten years of monitoring data to assess the timing and magnitude of historical water quality changes in Candlewood Lake, a large pumped-storage reservoir in western Connecticut, USA. The paleolimnological aspect of the study supported much of the current literature on both reservoir development and die effects of land-use alterations of watersheds on waterbodies. Water quality trends gleaned from the monitoring database confirmed recent conditions inferred from fossil assemblages. Monitoring data also provided evidence supporting an improvement in trophic conditions beginning around 1988, but a continued increase in dissolved salt levels. The paleolimnological study and die long-term monitoring effort complemented each other in that the former provided quantitative insight beyond die temporal scope of monitoring, while die resolution of die latter enabled managers to assess effective strategies. |
| Sixty Years of Lake Washington: a Curriculum Vitae | W. T. Edmondson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 75 - 84 | Sixty Years of Lake Washington: a Curriculum Vitae | The purpose of this paper is to list known disturbances of Lake Washington, to describe the effect on the lake of several of them, and to discuss results in terms of whole-lake quasi-experiments. Eutrophication with treated sewage effluent and the diversion of effluent are treated as experiments, with nutrient manipulation, which change the phytoplankton community structure. A later unexpected increase in transparency is traced through a chain of predators to flood control measures in the largest inlet. An increase in alkalinity, accompanied by changes in phytoplankton, is attributed to real estate land development. The role of paleolimnological information is illustrated. |
| Assessing Sediment Accumulation in a Eutrophic Lake in Northern New York | Thomas C. Young; Anthony G. Collins; Robert L. Sinsabaugh | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 85 - 93 | Assessing Sediment Accumulation in a Eutrophic Lake in Northern New York | We determined the pattern, rate, and extent of deposition of bulk sediments and sediment-bound phosphorus (P) in Black Lake. Vertical gradients in total phosphorus (TP) and 137Cs often were irregular within cores and variable among cores, reflecting sediment disturbances including bioturbation, resuspension, and lateral transport. Surface sediments exhibited a horizontal spatial gradient in TP content, with P levels that declined downstream from the lake inlet, which reflected a large input of settleable P from the primary tributary. Sediment 137Cs and TP data suggested an average lake-wide sediment accumulation rate of approximately 0.6 cm yr-1 since the early 1960s and greater accumulation of TP in 1975-90 than during 1960-75. The mean depth of sediment accumulation over bedrock was estimated to be at least 3.6 m. These data indicate the contemporary rate of water depth decrease due to sediment accumulation in Black Lake is much greater than the lake's postglacial average, and the rate of sediment P accumulation may have increased recently. |
| Seasonal and Spatial Variation in Algal Bloom Frequencies in Lake Okeechobee, Florida, U.S.A. | Karl E. Havens; Charles Hanlon; R. Thomas James | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 139 - 148 | Seasonal and Spatial Variation in Algal Bloom Frequencies in Lake Okeechobee, Florida, U.S.A. | This study quantified the seasonal and spatial distribution of algal blooms (defined as chlorophyll a >40 μg L-1) in Lake Okeechobee, based on 13 years of data collected from eight pelagic monitoring stations by the South Florida Water Management District Relationships between bloom frequencies and limnological parameters, including nutrient (nitrogen and phosphorus) loading rates, in-lake nutrient concentrations, Secchi transparencies, lake stage, and wind velocities, were investigated by rank correlation analyses. Blooms were found to vary both seasonally and spatially; they were most frequent during late spring and autumn, and they generally occurred in the northern and western regions of the pelagic zone. Blooms were least frequent in a central pelagic region where resuspension of soft mud sediments by wind produces frequent light limitation. Lake-wide bloom frequencies were uncorrelated with external loads of phosphorus and nitrogen, but were positively correlated with water temperatures (r = 0.19, p = 0.009) and Secchi transparencies (r = 0.22, p = 0.003). Blooms were negatively correlated with both wind velocity (r = -0.45, p = 0.05) and total phosphorus (r = -0.30, p < 0.001). The latter reflects a wind-driven resuspension of phosphorus-containing sediment particles, which produces low light availability and a subsequent decoupling of total phosphorus and algal blooms in this shallow lake ecosystem. |
| Relationships of Annual Chlorophyll a Means, Maxima, and Algal Bloom Frequencies in a Shallow Eutrophic Lake (Lake Okeechobee, Florida, USA) | Karl E. Havens | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 133 - 136 | Relationships of Annual Chlorophyll a Means, Maxima, and Algal Bloom Frequencies in a Shallow Eutrophic Lake (Lake Okeechobee, Florida, USA) | Fifteen years of historical data from Lake Okeechobee, Florida, were used to quantify relationships between annual mean and extreme values of algal biomass, measured as chlorophyll a Yearly chlorophyll a maxima and algal bloom frequencies (the percent of samples during a year containing >40 μg L-1 chlorophyll a) increased approximately 2-fold for each unit increase in the annual chlorophyll a mean, although there was some variation in these relationships among different regions of the lake. Threshold chlorophyll a concentrations (15-21 μg L-1) were also identified, below which bloom frequencies were reduced to near zero. Results indicate that if nutrient diversion strategies are successful in reducing annual mean chlorophyll a concentrations in Lake Okeechobee, even more pronounced reductions in algal blooms will occur. Reductions of lake-wide chlorophyll a means to early 1980s levels might nearly eliminate algal blooms as defined here. |
| Potamogeton crispus – The Other Invader | Brad R. Bolduan; Greg C. Van Eeckhout; Henry W. Quade; James E. Gannon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 113 - 125 | Potamogeton crispus - The Other Invader | Potamogeton crispus (Curlyleaf-pondweed) is an exotic macrophyte which has been introduced to the North American continent in the last century. P. crispus often grows to nuisance proportions at the expense of native macrophyte communities. A summary of available literature on P. crispus plus original data are presented to improve the understanding of this exotic and and in lake improvement projects. Topics include the life cycle of P. crispus is broken into sections covering the annual cycle of growth, reproduction, senescence and germination; environmental conditions associated with growth such as water quality, substrate characteristics and physical water conditions; nutrient dynamics of P. crispus covering the accumulation and concentration of nutrients found in P. crispus tissue; growth rate and biomass production; and various macrophyte control measures. |
| An Experimental Test of the Crayfish (Orconectes immunis) as a Control Mechanism for Submersed Aquatic Macrophytes | Michael A. Letson; Joseph C. Makarewicz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 127 - 132 | An Experimental Test of the Crayfish (Orconectes immunis) as a Control Mechanism for Submersed Aquatic Macrophytes | The ability of the crayfish Orconectes immunis to graze submersed aquatic macrophytes was evaluated experimentally. Crayfish at a biomass greater than 140-150 g m-2 (fresh weight) significantly decreased macrophyte biomass in all experiments. The rate of crayfish grazing in cages where significant decreases in macrophyte biomass occurred averaged 0.012 g m-2 day-1 crayfish-1 (ash-free dry weight) of macrophytes. |
| Macrophyte Influences on Sediment Resuspension and Export in a Shallow Impoundment | William F. James; John W. Barko | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 95 - 102 | Macrophyte Influences on Sediment Resuspension and Export in a Shallow Impoundment | Sediment resuspension dynamics and discharge of sediment downstream in Marsh Lake (Minnesota) were examined during 1991 and 1992 under a variety of wind conditions. Based on a theoretical wave model, nearly the entire sediment surface area (81-100%) can be disturbed by wave activity at wind velocities as low as 15 km/h blowing from any direction. As an apparent result of dense submersed macrophyte beds that in 1991 covered nearly the entire lake, measured sediment resuspension was much less frequent than expected from wave theory in 1991 than in 1992. Critical thresholds of wind velocity required to resuspend sediment were much higher in 1991 (~ 20 km/h) than in 1992 (~ 12 km/h), resulting in a lower frequency of resuspension events in 1991 (5%) than in 1992 (32%). Discharge of resuspended sediment to downstream Lac Qui Parle Reservoir was much less in 1991 when submersed macrophytes were abundant than in 1992 when macrophytes were absent. These results suggest that the development and maintenance of stands of submersed aquatic macrophytes may be an effective management tool for limiting wind-driven sediment resuspension and sediment discharge in shallow impoundments and lakes. |
| Chemical Classification and Trophic Characteristics of Texas Reservoirs | Ted A. Ground; Alan W. Groeger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 189 - 201 | Chemical Classification and Trophic Characteristics of Texas Reservoirs | Texas reservoirs were classified into three groups by cluster analysis based upon the following properties of their surface waters: specific conductance, alkalinity, calcium, sulfate, pH, chloride, and sodium (listed in descending order of importance as discriminators). The three groups of reservoirs had a distinct geographic distribution corresponding to a strong east-west gradient of increasing aridity and differences in surface geology. Chemical characteristics of the western reservoirs were most influenced by the dissolution of evaporites formed in the geological past and current arid conditions (median specific conductance = 1817 μS cm-1; median alkalinity = 120 mg CaCO3 L-1). Sulfate and chloride accounted for 87% of the major anions (in equivalent charge concentrations). The second group of reservoirs, located in a wide band through central Texas, were dominated by weathering of limestone bedrock and calcareous soils (median specific conductance = 518 μS cm-1; median alkalinity = 133 mg CaCO3 L-1). Alkalinity accounted for 53% of the anions. The eastern group, generally located on sedimentary muds and clays east of the Balcones/Ouachita trend, receive much higher runoff than other areas of the state. They were more dilute (median specific conductance = 185 μS cm-1; median alkalinity = 29 mg CaCO3 L-1), and alkalinity accounted for 45% of the anions. The central group had the highest proportion of oligotrophic reservoirs (30%) based on near-dam, growing season chlorophyll a concentrations, and also had the lowest concentrations of total phosphorus. Western and central reservoirs tended to be deeper with proportionally much smaller littoral zones, and precipitation of CaCO3 may be quite important in moderating the productivity of these impoundments, relative to reservoirs in eastern Texas. |
| Chemical and Physical Properties of Connecticut Lakes, With Emphasis on Regional Geology | Richard W. Canavan IV; Peter A. Siver | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 175 - 188 | Chemical and Physical Properties of Connecticut Lakes, With Emphasis on Regional Geology | Chemical and physical characteristics of 60 drainage lakes in Connecticut are discussed in relation to the geology of the state. Significant differences in composition and quantities of dissolved ions were observed for lakes in different geologic zones. Waterbodies situated on the Eastern Uplands, Western Uplands, and Coastal Slope were more dilute than lakes in the Marble and Central Valleys. Although there were significant differences in Na+, Ca+2, Mg+2, Cl-, SO4-2, and alkaline anions between different regions, none were found for K+. Unlike ionic chemistry, few differences in trophic variables were observed for lakes in the different geologic areas. On a statewide basis chlorophyll a levels were highly correlated with total phosphorus (TP), total nitrogen (TN), and Secchi disk depths. Summer TN:TP ratios suggested that chlorophyll levels in many lakes may be related to both TP and TN levels. Results are compared to previous studies in Connecticut and other areas of the northeast. |
| The Control of Saltwater Intrusion into Laguna de Bay: Socioeconomic and Ecological Significance | Adelina C. Santos-Borja | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 213 - 219 | The Control of Saltwater Intrusion into Laguna de Bay: Socioeconomic and Ecological Significance | Laguna de Bay is the largest lake in Southeast Asia. At present it is being used for fishery, irrigation, power generation, and navigation and is considered to be a source of potable water in the year 2000. The only outlet of the lake is the 24 km Pasig River which drains into Manila Bay. When the lake level is lower than Manila Bay, the Pasig River enters the lake via the Napindan Channel. However, the water is not only saline, but also deoxygenated and polluted with industrial and domestic effluents. The backflow of the Pasig River further aggravates die pollution problem in the lake. In 1983 a hydraulic control structure (HCS) was constructed at the confluence of the Pasig-Napindan River in order to prevent further pollution of the lake and to control the storage of lake water to firm up a dependable outflow for water supply and irrigation. However, operation of the HCS became a controversial issue among the different lake users. Fishermen and fishpen operators are against its operation because they claim it would reduce the natural food supply of fish especially the cultured milkfish. On the other hand, other sectors claim that the HCS is beneficial because it prepares the lake for its intended and future uses. Operation of the HCS continues to be a debatable issue and, due to pressures from different sectors, the HCS remains open from 1985 up to the present. |
| The TEAM Approach, “Together for Environmental Assessment and Managementâ€: A Process for Developing Effective Lake Management Plans or Water Resource Policy | Susan Littell Canfield; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 203 - 212 | The TEAM Approach, “Together for Environmental Assessment and Managementâ€: A Process for Developing Effective Lake Management Plans or Water Resource Policy | TEAM, “Together for Environmental Assessment and Management,†offers a new approach for developing comprehensive and integrative lake management plans and water resource policy. TEAM is a three-step process, one ideally sponsored by a legislative or executive arm of government. It involves “stakeholders,†lay citizens, and technical “experts†which may include academics, private professionals, and regulatory or management agency personnel. Using the TEAM approach, stakeholders and lay citizens together in a citizens' forum identify, define, and prioritize their concerns and potential courses of action concerning a water resource issue (s). Then, “pro†and “con†teams of professionals provide technical information and a peer-reviewed debate of technical aspects of citizens' concerns. Last, with this information citizens discuss and ultimately vote on a course(s) of action with regard to a lake management plan or a water resource policy. The recommendation(s) of citizens is provided to appropriate policymakers and the public. The goal of the TEAM approach is to improve upon traditional modes of public participation and scientific peer review in order to more efficiently and effectively integrate them with the policy making process. TEAM does this with four basic strengths. First, unlike traditional approaches where lay citizens and professionals work as a single unit, TEAM provides citizens and technical experts with separate but complementary forums and responsibilities. Second, TEAM ensures that opinions of stakeholders as well as those of the public-at-large are fairly represented. Third, TEAM structures a timely, constructive debate of politically relevant technical issues using the familiar structure of scientific peer review. Through a pro versus con debate, it promotes identification and definition of points of scientific agreement, disagreement, and uncertainty. Last, TEAM can bring long-term cost-effectiveness to the policy making process, particularly in terms of saving the time of human resources. |
| Phytofences and Algae Harvesting as Control Strategies for H2S Emissions from Saline Ponds | Marcie L. Commins; James C. Roth; David Jenkins | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 149 - 154 | Phytofences and Algae Harvesting as Control Strategies for H2S Emissions from Saline Ponds | Excessive atmospheric H2S (hydrogen sulfide) emissions from large salt evaporation ponds in San Francisco Bay, California, and the effectiveness of possible remedies have been studied since 1989. These emissions are caused by filamentous algae (Cladophora spp., Enteromorpha spp.) which accumulate on the downwind shores, and decay under anoxic conditions. On-site pilot experiments were used to test the effectiveness of two methods of controlling H2S emissions: harvesting the shoreline accumulation of filamentous algae and the use of a barrier (“phytofenceâ€) to prevent accumulation of algae onshore. Replicate experimental plots were set up along a portion of the downwind (east) shore. Atmospheric H2S concentrations above the phytofence plots were significantly lower than above both control and harvest plots. In addition, total dissolved sulfide was significantly lower and dissolved oxygen significantly higher in the phytofence plots than in control and harvest plots. Thus, a phytofence may be a viable method for reducing H2S emissions. Harvest plot H2S emissions, total dissolved sulfide, and dissolved oxygen concentrations were not significantly different from control plots. Removal of filamentous algae to significantly reduce the H2S emissions is impractical early in the season due to large amounts of algae involved and the difficulty of harvesting; it is impossible later in the season because of the decomposed state of the algae. Harvesting is not a viable method for reducing H2S emissions from these evaporation ponds. |
| Response of a Shallow, Polymictic Lake to Buffered Alum Treatment | Jean M. Jacoby; Harry L. Gibbons; Kevin B. Stoops; Debra D. Bouchard | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 103 - 112 | Response of a Shallow, Polymictic Lake to Buffered Alum Treatment | The first aluminum sulfate (alum) and sodium aluminate lake treatment in Washington State was performed in Green Lake, a shallow (mean depth = 3.9 m), highly eutrophic, polymictic lake in Seattle. During October 1991, 181 tons of alum and 76.5 tons of sodium aluminate were applied to attain a total aluminum dose of 8.6 mg L-1. The use of sodium aluminate as a buffering agent allowed a higher dose of alum to be used, and maintained lake pH (6.7) and alkalinity (28 mg CaCO3 L-1) during treatment Secchi disk transparency increased from 1.9 to 6.1 m following treatment and remained higher throughout 1992 and 1993 than in pretreatment years with summer means of 3.5 and 2.9 m, respectively. Total phosphorus (TP) concentrations decreased from a mean of 40 μg L-1 before treatment to 14 μg L-1 immediately following treatment and remained below 29 μg L-1 during 1992 and below 35 μg L-1 during 1993. The 1992 and 1993 whole-lake, mean summer TP concentrations of 20 and 26 μg L-1. respectively, met the lake management goal of 30 μg L-1. Blue-green algal blooms were greatly reduced, despite the absence of summer dilution water inputs. Mean summer 1992 and 1993 chlorophyll a concentrations were 7.1 and 12.6 μg L-1; these concentrations were a marked improvement from the 1981 summer mean concentration of 28 μg L-1. The effectiveness of the alum/sodium aluminate treatment was critical in determining that the proposed $4.5 million, 11400 m3day-1 water treatment plant, which would have provided low-nutrient dilution water to Green Lake, would not yield the desired improvement in lake water quality. |
| Biomanipulation at Rice Lake, Ontario, Canada | Jill E. Badgery; Donald J. McQueen; Ken H. Nicholls; Paul R. Schaap | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 163 - 173 | Biomanipulation at Rice Lake, Ontario, Canada | The potential for using biomanipulation to reduce algal standing stocks and improve water clarity was investigated during 1988 and 1989 at Rice Lake, Ontario, Canada. During both study years, fish bioenergetics simulations showed that for a short period in the spring food consumption by young-of-the-year (YOY) yellow perch could account for almost all of the Daphnia (primarily Daphnia galeata mendotae) population losses that were calculated from a secondary production model applied to daphnids. However, during summer, YOY perch densities decreased and YOY perch community consumption rates became much lower than Daphnia production rates. This was associated with an order of magnitude increase in Daphnia biomass. Despite these dramatic summer increases in daphnid biomasses, chlorophyte and cyanophyte biovolumes and chlorophyll a concentrations increased more than five fold, and Secchi depths decreased from spring values greater than 2 m to summer values less than 1 m. Through both summers, increased algal biomasses were associated with increased total phosphorus concentrations and with late spring die-backs of the extensive macrophyte beds (primarily Potamogeton crispus) that developed during early spring. These data suggest that at Rice Lake algal production and biomass are strongly influenced by bottom-up factors, and it is unlikely that top-down biomanipulations offish populations could stimulate additional Daphnia biomass or lead to improvement of water clarity. |
| Empirical Relationships for Sport Fish Yield Based on Manipulable Variables | Gregory C. Scarborough; Robert H. Peters | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 2 | 1994 | 155 - 162 | Empirical Relationships for Sport Fish Yield Based on Manipulable Variables | Although most authors accept that trophic status and angler effort affect fish yield, few predictive relationships use both variables because both are rarely available in the same data set. To fill this lacuna, we have developed a data set representing lakes of various trophic levels lying on both igneous and sedimentary drainage basins in Ontario. These data include estimates of sport fish yield, lake morphometry, lake chemistry, and fishing effort. With these data, we developed five models. None of these models were significantly better than the rest but all predicted sport fish harvest effectively despite the presence of ratios in three of the models. The model that is most attractive because it contains no ratios, explains 86% of the variation in sport fish catch, and uses manipulable variables, is: log10 catch (kgseason-1) = 0.685 log10 angler hours (hoursseason-1) + 0.366 log10 TP (total phosphorus)-area (mg m-1) - 0.124 (log10 mean depth)3 (m) -1.028. |
| Submersed Plant Invasions and Declines in New York | John E. Titus | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 25 - 28 | Submersed Plant Invasions and Declines in New York | Control of nuisance species appears to be the primary goal of aquatic plant management in New York State. The three principal species of concern are Myriophyllum spicatum L. (Eurasian watermilfoil), Potamogeton crispus L. (curly pondweed), and Trapa natans L. (water chestnut). A wide range of lake types are apparently colonized by nuisance macrophyte species; these range from acidic, disturbed, oligotrophic lakes to alkaline, eutrophic lakes. Hand harvesting, mechanical harvesting, drawdown, and herbicides have been used for aquatic plant control in the state. Populations of native aquatic plants are stable to declining. There is no clear relationship between invasion of exotics and decline of native species. |
| Invasions and Declines of Submersed Macrophytes in Lake George and Other Adirondack Lakes | John D. Madsen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 19 - 23 | Invasions and Declines of Submersed Macrophytes in Lake George and Other Adirondack Lakes | Management of nuisance aquatic plants in New York state is directed toward the exotic species, Myriophyllum spicatum, Potamogeton crispus, Trapa natans, and Cabomba caroliniana. Public access to a lake may be the number one factor contributing to invasion by M. spicatum. All types of lakes in the Adirondack Mountain region have been invaded by this species except acid lakes. In shallow, eutrophic lakes the entire littoral zone is often comprised of M. spicatum growing to the surface, whereas populations in more oligotrophic lakes form isolated patches. Native plant species in general appear to be stable, except where exotic species have colonized and are dominating. |
| Preliminary Evaluation of Submersed Macrophyte Changes in the Upper Mississippi River | S. J. Rogers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 35 - 38 | Preliminary Evaluation of Submersed Macrophyte Changes in the Upper Mississippi River | Declines in submersed aquatic macrophytes, notably Vallisneria americana Michx., recently have been observed in portions of the Upper Mississippi River (UMR). Coincidentally, Myriophyllum spicatum L. appears to have become more common, frequently occurring in locations formerly occupied by Vallisneria or other submersed aquatic species. Mechanisms causing these changes in the abundance and composition of aquatic vegetation are unknown. However, a 3-year drought may have affected nutrient transport and phytoplankton production, thereby influencing growth and reproduction of Vallisneria and other macrophyte species. Other factors may potentially affect populations of submersed macrophytes within the UMRS. Foremost among these are suspended sediment concentrations, flooding, herbicides, and grazing. |
| Evaluation of Invasions and Declines of Submersed Macrophytes for the Upper Great Lakes Region | Stanley A. Nichols | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 29 - 33 | Evaluation of Invasions and Declines of Submersed Macrophytes for the Upper Great Lakes Region | In the upper Great Lakes region, Myriophyttum spicatum, Elodea canadensis, Potamogeton crispus, and Ceratophyllum demersum are the most significant nuisances. M. spicatum and P. crispus have generally invaded lakes with hard water, abundant nutrients, and a history of disturbance or heavy human use. M. spicatum has declined in some Wisconsin lakes, but not in all that it invaded. The reason for declines was never satisfactorily explained. Following its decline in Madison, WI, lakes, the M. spicatum population never regained its former predominance. There are no long-term data to determine whether populations of native macrophyte species are expanding, stable, or declining on a regional basis, although diversity of the aquatic plant communities of Madison-area lakes has declined over the last 80 years. Most aquatic plant management in the upper Great Lakes region involves controlling nuisance species. Herbicides and mechanical harvesting are the primary means of management, although drawdowns, bottom blanketing, and other methods are also used. Minnesota and Wisconsin have public education programs intended to promote early detection of nuisance species and to minimize their spread. In Wisconsin, reintroduction of aquatic vegetation to lakes is being attempted on an experimental basis for a variety of reasons, including fish and wildlife habitat and water-quality improvement. |
| Submersed Macrophytes in the Canadian Prairies: Dealing with Home-grown Problems | P. A. Chambers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 5-8 | Submersed Macrophytes in the Canadian Prairies: Dealing with Home-grown Problems | There are no reports of exotic macrophyte species causing management problems in the Canadian prairies. However, the spread of Myriophyllum spicatum throughout the U.S. and parts of Canada poses concerns to water managers in the Canadian prairie provinces. Given the wide range of environmental conditions that this species can tolerate, it is unlikely that environmental factors prevent its establishment in prairie waterbodies. It is most likely that climatic and geographic constraints have, to date, prevented introduction of M. spicatum in to the Canadian prairies. In the event that this or other exotic species are introduced to the Canadian prairies, it is difficult to predict whether they will grow to nuisance levels, since many of these lakes already support high submersed macrophyte biomass. In lakes and large rivers of the Canadian prairies, aquatic macrophyte growth is favored by nutrient-rich sediments and, in rivers, high water clarity. At present there are no provincial or federal agencies whose mandate is aquatic plant control. Since existing aquatic plant problems are caused by native species, these problems are viewed as a natural state. |
| Perspectives on Submersed Macrophyte Invasions and Declines | J. W. Barko; C. S. Smith; P. A. Chambers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 1-3 | Perspectives on Submersed Macrophyte Invasions and Declines | Invasions and declines of submersed macrophyte communities have been reported worldwide. In general, factors contributing to invasions are most poorly understood. Factors potentially contributing to macrophyte declines are numerous, and include reduced irradiance, nutrient depletion, parasites and pathogens, toxin accumulation, animal damage, climatic fluctuations, and other factors. Attention to these dynamics in submersed macrophyte communities is of more than academic interest, since coordination of macrophyte management policies and procedures with natural controls could improve the efficiency of macrophyte management efforts. Indeed, there is some evidence that intense management may prolong the dominance of invasive exotic submersed macrophyte species. As part of the International Symposium on the Biology and Management of Aquatic Plants, held in July 1992 in Daytona Beach, FL, a workshop was conducted to better understand invasion and decline phenomena, from a regional perspective, within the context of aquatic plant management. |
| Invasions and Declines of Submersed Macrophytes in New England, with Particular Reference to Vermont Lakes and Herbivorous Invertebrates in New England | S. P. Sheldon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 13 - 17 | Invasions and Declines of Submersed Macrophytes in New England, with Particular Reference to Vermont Lakes and Herbivorous Invertebrates in New England | Nuisance aquatic plants are found throughout New England. Plant presence or absence in a lake appears to be limited more by dispersal than by inappropriate abiotic or biotic conditions. While some nuisance macrophyte species are still spreading to new lakes, there have also been declines reported for Myriophyllum spicatum and M. heterophyllum in three New England states. The cause(s) of these declines are still unclear. However, in all lakes in which declines have occurred herbivorous macroinvertebrate species known to feed on Myriophyllum spp. have been found. |
| Case Study: Blue-green Algal Control in Australia by Year-round Automatic Aeration | Frank L. Burns | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 61 - 67 | Case Study: Blue-green Algal Control in Australia by Year-round Automatic Aeration | Intermittent artificial aeration was initiated in Little Bass Reservoir in the summer of 1981-82 with the goal of solving water quality problems including unpleasant tastes and odors, high levels of iron and manganese, poor bacteriological quality and regular summer blue-green algal blooms. Monitoring was carried out for the next 12 years to evaluate changes in water quality. With the initial operation, consisting of manual aeration applied only in summer months, stratification control was not consistent and blue-green algal blooms continued. However, since 1985 more consistent control over stratification has been achieved by applying year-round automatic aeration triggered by the intermittent stratification conditions in the reservoir, and no blooms of blue-green algae have been experienced for the past 7 years. A logical explanation for this experience, which has been reproduced by the author in many other Australian lakes and reservoirs, is that by introducing year-round automatic aeration, the continuously well oxygenated conditions produced at the bottom sediments prevented reducing conditions from developing and so restricting recycling of nutrients in a soluble form available for algal growth. |
| Workshop Synthesis | P. A. Chambers; J. W. Barko; C. S. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 57 - 59 | Workshop Synthesis | During the past 60 years, aquatic macrophyte species have been discovered with increasing frequency in geographic regions where they had not previously been found, apparently due to greater dispersal resulting from human activities and better documentation of plant distribution. Intercontinental invasions have generally been well documented. However, the spread of exotic or native species across continents has received little attention. Given this introductory information, the aim of the workshop was to identify examples of invasions or natural declines of aquatic macrophyte species throughout the world and assess the importance of environmental factors in their control. While chance was acknowledged as an important factor determining species invasions, factors determining successful establishment following invasion were recognized to vary with the spatial scale of consideration (e.g., continent vs. lake district). Few natural declines of aquatic macrophytes have been studied quantitatively, although personal accounts suggest that these declines may be common. Presently, there is limited evidence of biotic controls of declines due to a lack of “before and after†data. In contrast, abiotic factors have been documented as causing declines in aquatic macrophyte communities. Management practices can potentially influence both invasions and declines. |
| Erratum | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 74 | Erratum | |
| Load Limits For Lakes | Lowell L. Klessig | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 69 - 73 | Load Limits For Lakes | Loading of lakes with nutrients, especially phosphorus, has been the central concern of limnologists. However, lakes are also loaded with users, which directly impacts the recreational experiences. This essay, using Wisconsin as an example, explores why lake managers have been reluctant to manage lake use. It also develops an analogy with public highway regulation and suggests that load limits could be put on watercraft just as they are put on trucks. Finally, the essay suggests that lake use policies be based on integrating four primary goals: aesthetic opportunity, recreational opportunity, environmental security, and economic opportunity. |
| Invasions and Declines of Submersed Macrophytes in the Tidal Potomac River and Estuary, the Currituck Sound-Back Bay System, and the Pamlico River Estuary | Virginia Carter; N. B. Rybicki | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 39 - 48 | Invasions and Declines of Submersed Macrophytes in the Tidal Potomac River and Estuary, the Currituck Sound-Back Bay System, and the Pamlico River Estuary | Long-term changes in biomass, species composition, and distribution of submersed aquatic macrophytes have been documented and studied at two sites in the mid-Atlantic region: the tidal Potomac River and Estuary in Maryland, Virginia, and the District of Columbia, and the Currituck Sound-Back Bay system in Virginia and North Carolina. Additional information based on a shorter time period is available for the Pamlico River Estuary in North Carolina. This paper briefly describes the study areas and summaries the history of declines and increases in each area and factors implicated in these changes. The remainder of the paper is devoted to a discussion of factors influencing invasion/establishment success and the current status of submersed macrophytes in the three areas. |
| Potential Role of Plant Pathogens in Declines of Submersed Macrophytes | Judy F. Shearer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 9-12 | Potential Role of Plant Pathogens in Declines of Submersed Macrophytes | The role of plant disease in determining distribution and abundance of submersed aquatic macrophytes has rarely been studied. The most definitive case of a microbial agent causing decline of a submersed aquatic plant is the wasting disease of eelgrass, Zostera marina L., which is caused by a marine slime mold. Plant pathogens have also been suggested as a potential cause of Myriophyllum spicatum declines in Chesapeake Bay and in Madison, WI, area lakes. Attempts to identify pathogens for use in biological control of submersed plants have yielded several promising microorganisms, but much effort has been expended on relatively weak pathogens. More attention needs to be given to conditions under which pathogens are evaluated, since characteristics of the chemical and physical environment and of the host population itself may determine the amount of disease which occurs. In the near future, biocontrol efforts may benefit from expected changes in U.S. Department of Agriculture regulations which will allow importation of host-specific pathogens of introduced aquatic plant species collected from the native ranges of the plants. |
| Submersed Plant Invasions and Declines in the Southeastern United States | A. Leon Bates; Craig S. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 53 - 55 | Submersed Plant Invasions and Declines in the Southeastern United States | In the southeastern U.S., distributions of exotic submersed macrophyte species such as hydrilla and Eurasian watermilfoil are expanding, whereas most populations of native submersed macrophytes appear to be stable or declining. In this region, control of nuisance species is the predominant goal of aquatic plant management. Herbicide treatment is the most common control technique used. Water level fluctuations are routinely used to control submersed plants in impoundments. Declines in submersed vegetation were reported from many locations in the region, often coinciding with invasion by exotics. From 1989 through 1991, submersed vegetation declined substantially in much of the region, coincidental with declines in other parts of eastern North America. Improved growing conditions in 1992 and 1993 have led to a partial recovery of aquatic vegetation in most of these areas. |
| Chesapeake Bay Submersed Aquatic Vegetation: Water Quality Relationships | Robert J. Orth | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 10 | 1 | 1994 | 49 - 52 | Chesapeake Bay Submersed Aquatic Vegetation: Water Quality Relationships | In Chesapeake Bay, a baywide decline of all submersed aquatic vegetation (SAV) began in the late 1960s. The decline was related to increasing amounts of nutrients and sediments resulting from shoreline and watershed development. In the bay, SAV are rarely considered a nuisance, since they contribute to high baywide productivity and habitat quality. Because SAV is a critical part of the bay's food chain and is sensitive to water quality, it is considered a potential indicator of the bay's health. A conceptual model was developed, which illustrates water quality parameters that influence SAV distribution and abundance. Environmental factors contributing to light attenuation were used to formulate SAV habitat requirements. SAV habitat requirements based on specific water quality standards represent characteristics minimally necessary to sustain plants in shallow water. Improvements in water quality in the bay are predicted to result in increases in the density and biomass of SAV. |
| GIS and Remote Sensing as Tools for Conducting Ecological Risk Assessments | C. G. Crabtree; B. D. McGaughey; E. B. Henriksen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 84 - 87 | GIS and Remote Sensing as Tools for Conducting Ecological Risk Assessments | |
| Comparison of Nonpoint Pollutant Loadings From Geographic Information System Modeling and Wet Weather Stream Flow Monitoring | Mark R. Ernst; Woody Frossard; Darrel W. Andrews | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 79 - 84 | Comparison of Nonpoint Pollutant Loadings From Geographic Information System Modeling and Wet Weather Stream Flow Monitoring | |
| Wetland Water Quality Impacts in Developing Watersheds: Empirical Models and Biological Indicators | Kenneth A. Ludwa | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 75 - 79 | Wetland Water Quality Impacts in Developing Watersheds: Empirical Models and Biological Indicators | |
| Oligotrophication of Lake Shenipsit by Layer Aeration | Robert W. Kortmann | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 94 - 97 | Oligotrophication of Lake Shenipsit by Layer Aeration | |
| Treatment of Acid Production in Dredged Sediments | Tom Murphy; Annette Moller; Phil Manning; Rick Bourbonniere; Mike Mawhinney; Jay Babin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 91 - 94 | Treatment of Acid Production in Dredged Sediments | |
| Stormwater Filtration Techniques Used in Green Lake Water Quality Improvement Program | Kevin B. Stoops; Cheryl Paston; Herman Wong | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 88 - 90 | Stormwater Filtration Techniques Used in Green Lake Water Quality Improvement Program | |
| Optimum Growth Conditions For Potamoqeton amplifolius, Myriophyllum spicatum and Potamoqeton richardsonii | R. W. Wakeman; D. H. Les | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 129 - 133 | Optimum Growth Conditions For Potamoqeton amplifolius, Myriophyllum spicatum and Potamoqeton richardsonii | |
| Interspecific Competition Between Potamogeton amplifolius and Myriophyllum spicatum | R. W. Wakeman; D. H. Les | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 125 - 129 | Interspecific Competition Between Potamogeton amplifolius and Myriophyllum spicatum | |
| Algae Control for an Urban Estuary: Lake Merritt in Oakland, California | John Hake | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 122 - 125 | Algae Control for an Urban Estuary: Lake Merritt in Oakland, California | |
| Effects of Nutrient Enhancement on Juvenile Sockeye Salmon Growth | Phaedra Budy; Chris Luecke; Wayne Wurtsbaugh; Howard Gross | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 140 - 145 | Effects of Nutrient Enhancement on Juvenile Sockeye Salmon Growth | |
| Managing Eurasian Watermilfoil in British Columbia | Peter R. Newroth | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 136 - 140 | Managing Eurasian Watermilfoil in British Columbia | |
| Potential Impacts of Purple Loosestrife and its Control on Wetlands in Washington State: An Evaluation of Research Needs | Susan Gardner Arroll; Christian E. Grue; Chuck J. Perry; Gary L. Piper | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 133 - 136 | Potential Impacts of Purple Loosestrife and its Control on Wetlands in Washington State: An Evaluation of Research Needs | |
| The Effects of Destratification Aeration on Five Minnesota Lakes | Robert J. Beduhn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 105 - 110 | The Effects of Destratification Aeration on Five Minnesota Lakes | |
| Oxygenation And Agitation Of Lakes Using Proven Marine Technology | Endicott M. Fay | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 102 - 105 | Oxygenation And Agitation Of Lakes Using Proven Marine Technology | |
| Aeration And Pollutant Abatement In The Helpe Mineure River, Fourmies, France | Robert L. Laing; Carlton J. Rausch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 98 - 102 | Aeration And Pollutant Abatement In The Helpe Mineure River, Fourmies, France | |
| Sources Of Taste And Odor Problems In Lake Youngs, A Municipal Drinking Water Reservoir | R. Robert Zisette; Jory S. Oppenheimer; Richard Donner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 117 - 122 | Sources Of Taste And Odor Problems In Lake Youngs, A Municipal Drinking Water Reservoir | |
| Iron Treatment For Eutrophication Control In Black Lake, British Columbia | Kenneth J. Hall; Thomas P. D. Murphy; Michael Mawhinney; Kenneth I. Ashley | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 114 - 117 | Iron Treatment For Eutrophication Control In Black Lake, British Columbia | |
| Short Term Changes In Newman Lake Following Hypolimnetic Aeration With The Speece Cone | Jennifer A. Thomas; William H. Funk; Barry C. Moore; William W. Budd | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 111 - 113 | Short Term Changes In Newman Lake Following Hypolimnetic Aeration With The Speece Cone | |
| Applications and Limitations of Qualitative Lake Assessment Data | Scott A. Kishbaugh | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 17 - 23 | Applications and Limitations of Qualitative Lake Assessment Data | |
| Citizen Involvement in the Enhancement of Woodland Creek and Lake Lois | Doug Gresham; Jared Burbidge | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 14 - 17 | Citizen Involvement in the Enhancement of Woodland Creek and Lake Lois | |
| The Establishment of an Integrated Reservoir and Watershed Water Quality Management Program in Taiwan | Dale E. Anderson; Charles H. Tang; Jory S. Oppenheimer; H. C. Chao; Johnnie Tsai; T. C. Chang; T. Y. Wu | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 31 - 36 | The Establishment of an Integrated Reservoir and Watershed Water Quality Management Program in Taiwan | |
| USDA Forest Service, Region 6, Alpine Lake Survey Protocol | Denise R. Hann | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 24 - 30 | USDA Forest Service, Region 6, Alpine Lake Survey Protocol | |
| Quality Assurance Testing for a Large Scale Volunteer Monitoring Program: The Acid Rain Monitoring Project | Mark D. Mattson; Marie-Françoise Walk; Peter A. Kerr; Anne M. Slepski; O. Thomas Zajicek; Paul J. Godfrey | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 10 - 13 | Quality Assurance Testing for a Large Scale Volunteer Monitoring Program: The Acid Rain Monitoring Project | |
| INDEX TO AUTHORS | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 2 | 1994 | 128 - 131 | INDEX TO AUTHORS | |
| Abstracts of Presentations, North American Lake Management Society, Orlando, Florida, 1994 | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 2 | 1994 | 50 - 127 | Abstracts of Presentations, North American Lake Management Society, Orlando, Florida, 1994 | |
| Detecting Water Quality Trends With Citizen Volunteer Data | Steve Heiskary; Jennifer Lindbloom; C. Bruce Wilson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 4 - 9 | Detecting Water Quality Trends With Citizen Volunteer Data | |
| A Profile of Volunteer Environmental Monitoring: National Survey Results | Meg Kerr; Eleanor Ely; Virginia Lee; Alice Mayio | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 1 - 4 | A Profile of Volunteer Environmental Monitoring: National Survey Results | |
| Beaver Lake: Can Lake Protection Work? | Sharon P. Walton; Dale E. Anderson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 61 - 65 | Beaver Lake: Can Lake Protection Work? | |
| Management of Lake Elizabeth, Fremont, California, For Competing Resource Values | Gary Halsey | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 57 - 60 | Management of Lake Elizabeth, Fremont, California, For Competing Resource Values | |
| Natural Phosphorus Control in a Terminal Lake: Implications for Lake Management | M. E. Lebo; J. E. Reuter; C. R. Goldman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 72 - 74 | Natural Phosphorus Control in a Terminal Lake: Implications for Lake Management | |
| Lake Waramaug 1975–1993 … What We've Learned | Robert W. Kortmann | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 65 - 71 | Lake Waramaug 1975-1993 … What We've Learned | |
| Innovative Funding for the China Lake Restoration Project | George W. Lord; Gary L. Brown | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 54 - 57 | Innovative Funding for the China Lake Restoration Project | |
| Successful Comprehensive and Consensus-Based Resource Management Planning For Lakes And Reservoirs | John A. Petrovsky | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 42 - 46 | Successful Comprehensive and Consensus-Based Resource Management Planning For Lakes And Reservoirs | |
| Application of Economic Value Functions to a System Analysis Model of the Columbia River | L. Leigh Skaggs; David A. Moser; David J. Hill | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 37 - 42 | Application of Economic Value Functions to a System Analysis Model of the Columbia River | |
| Watershed Protection Through Education: The Sebago Lake Project | Jody Smith; Ron Faucher | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 50 - 53 | Watershed Protection Through Education: The Sebago Lake Project | |
| Sustainable Development on a Watershed Scale Russian Case Study—Pronya River | Alexey Voinov; Alan Cibuzar; Tatiana Nawrocki | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 46 - 50 | Sustainable Development on a Watershed Scale Russian Case Study—Pronya River | |
| Implications of Reservoir Release and Tailwater Monitor Placement | M. C. Vorwerk; J. H. Carroll | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 170 - 172 | Implications of Reservoir Release and Tailwater Monitor Placement | |
| Using Hydroacoustics to Monitor Fish at Hydropower Dams | Bruce H. Ransom; Tracey W. Steig | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 163 - 169 | Using Hydroacoustics to Monitor Fish at Hydropower Dams | |
| Restoration and Management of Lake Sevan in Armenia: Problems and Prospects | Rafael Hovanesian; Harry Bronozian | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 178 - 182 | Restoration and Management of Lake Sevan in Armenia: Problems and Prospects | |
| The Lower Columbia River Bi-State Program 1991 Reconnaissance Survey | Steven G. Ellis; Curtis L. DeGasperi | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 172 - 178 | The Lower Columbia River Bi-State Program 1991 Reconnaissance Survey | |
| Lake Washington Fish: A Historical Perspective | Kurt L. Fresh | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 148 - 151 | Lake Washington Fish: A Historical Perspective | |
| Feeding Behavior of Longfin Smelt (Spirinchus thaleichthys) May Affect Water Quality and Salmon Production in Lake Washington | Thomas H. Sibley; Paulinus Chigbu | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 145 - 148 | Feeding Behavior of Longfin Smelt (Spirinchus thaleichthys) May Affect Water Quality and Salmon Production in Lake Washington | |
| Review Of Spring And Summer Spill Effectiveness For Juvenile Salmon And Steelhead At Various Columbia And Snake River Dams 1983-1992 | Tracey W. Steig | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 154 - 162 | Review Of Spring And Summer Spill Effectiveness For Juvenile Salmon And Steelhead At Various Columbia And Snake River Dams 1983-1992 | |
| Spatial and Temporal Dynamics of Piscivory: Implications for Food Web Stability and the Transparency of Lake Washington | David A. Beauchamp | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 9 | 1 | 1994 | 151 - 154 | Spatial and Temporal Dynamics of Piscivory: Implications for Food Web Stability and the Transparency of Lake Washington | |
| Groundwater/Surface Water Interaction in a Florida Augmentation Lake | Thomas V. Belanger; Robert A. Kirkner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 165 - 174 | Groundwater/Surface Water Interaction in a Florida Augmentation Lake | Mountain Lake, Florida, is augmented with water pumped from the underlying Floridan aquifer to maintain the water level, and a detailed 1990 water budget was developed for this lake to determine how the lake interacts with the surrounding groundwater system. Groundwater interaction with the lake was calculated from flow-net analysis of surficial well data, seepage meter data, and the residual of the water budget equation. Strong leakage through the lake bottom was observed, primarily controlled by the head difference between the lake and the Floridan aquifer and the sediment hydraulic leakance (sediment hydraulic conductivity/thickness). Areas of seepage into the lake (15% of the lake area) were observed at possible sinkhole features in the central portion of the lake. Areas of strong leakage occurred in shore areas where steep outflow gradients and sandy sediments existed. Results from this study indicate that the lake recycles groundwater, as the equivalent of over 90% of augmentation water returns to the groundwater system. Water budget data from this lake dispute the public perception in Florida that lake augmentation is a wasteful practice. |
| Zooplankton, Fish and Sport Fishing Quality Among Four Alabama and Georgia Reservoirs of Varying Trophic Status | David R. Bayne; Michael J. Maceina; William C. Reeves | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 153 - 163 | Zooplankton, Fish and Sport Fishing Quality Among Four Alabama and Georgia Reservoirs of Varying Trophic Status | Four mainstream river impoundments located in Alabama and Georgia were examined in 1989 and 1990 to determine the response of zooplankton and fish to trophic gradient. Mean chlorophyll a concentrations ranged from 2 μg/L in the mesotrophic lake to 34 μg/L in the highly eutrophic lake. Two of the lakes were moderately eutrophic with mean chlorophyll a concentrations of 13 and 15 μg/L. Rotifer and total zooplankton densities increased with increasing trophic status, but crustacean zooplankton densities and biomass did not. Estimates of fish abundance and biomass were positively related to trophic state. Forage fish community structure in the mesotrophic lake was numerically comprised of Iepomid sunfish (47%), cyprinid minnows (20%) and shad (Dorosoma) (13%), but shad comprised 45% to 53% of the fish community in the eutrophic lakes. Black bass (Micropterus spp.) growth rates were similar in all lakes, however crappie (Pomoxis spp.) grew faster in the more eutrophic reservoirs. Fishing effort adjusted for lake size was positively related to trophic gradient. Total weight and number of fish harvested was highest in the most eutrophic lake, but highest harvest per unit effort occurred in the mesotrophic lake. Generally, larger fish were caught in the eutrophic lakes than in the mesotrophic lake, and angler-caught black bass size was similar among the three eutrophic lakes. Trophic gradient was not related to angler perception of fishing success nor to where anglers chose to hold their fishing tournaments. Reservoirs with mean growing-season (May-September) chlorophyll a concentrations between 10 and 15 μg/L may provide black bass and crappie fisheries that are similar to those fisheries of more productive lakes. |
| Water Quality, Fishery, and Biologic Characteristics in a Shallow, Eutrophic Lake with Dense Macrophyte Populations | Barry C. Moore; William H. Funk; Eric Anderson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 175 - 188 | Water Quality, Fishery, and Biologic Characteristics in a Shallow, Eutrophic Lake with Dense Macrophyte Populations | Giffin Lake is a shallow, eutrophic lake in south central Washington and the sub ject of an intensive Phase I restoration diagnostic/feasibility study. Water quality problems in the lake have been manifested principally as excessive growth of the floating-leaved macrophyte, Nymphaea odorata, white water lily. Study results indicate that these macrophytes play a central role in chemical, physical, and biological functioning of the lake. The extensive macrophyte canopy prevents diffusion of oxygen to the sediments by inhibiting both gas exchange with the atmosphere and transfer of wind energy to the water column. Anaerobic conditions develop under the summer macrophyte canopy, as do steep nutrient gradients. Phytoplankton seasonal distribution appears to be strongly influenced by competition with macrophytes for nutrients and light. Zooplankton communities are dominated by rotifers which can tolerate low oxygen conditions and which feed on bacteria and detritus prevalent beneath the macrophytes. Fish population distributions, with the exception of carp, are skewed to older and larger individuals, in constrast to those typically observed in lakes with less macrophyte biomass. Fish condition factors are generally below the average for Washington lakes. Recruitment to gamefish populations appears to be poor due to reproductive failures and low growth rates, resulting from the stresses of high temperatures, low summer oxygen concentrations, and predation from carp. Restoration of Giffin Lake would require removal of the majority of the sediments and macrophytes. Currently, the status of Giffin Lake as a wetland may bring such restoration efforts into conflict with wetland protection programs. The need for a means of assessing wetlands value in the management, protection, and restoration of shallow lakes/wetlands is discussed. |
| Erratum | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 210 | Erratum | |
| Phytoplankton Bloom Frequencies in a Population of Small Southeastern Impoundments | R. L. Raschke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 205 - 210 | Phytoplankton Bloom Frequencies in a Population of Small Southeastern Impoundments | Corrected chlorophyll a data were gathered for 17 small southeastern piedmont impoundments <648 ha (<1600 a) ranging in trophic state from mesotrophic to hypereutrophic. Working with the managerial concept that water-use impacts are more directly related to frequency of blooms than to mean seasonal values, regression equations were calculated to relate bloom frequency to seasonal mean chlorophyll a concentrations. The relationship between bloom frequency (chlorophyll a ≥30 μg/L) and mean chlorophyll a concentration in this study was very similar to that found for U.S. Army Corps of Engineers (COE) impoundments. Based on this bloom frequency analysis, literature values, and experience, a mean growing season limit of ≤15 (μg/L of chlorophyll a is recommended for small southeastern piedmont water supply impoundments. For other water uses, a mean growing season chlorophyll a concentration of <25 μg/L is recommended to maintain a minimal aesthetic environment for viewing pleasure, safe swimming, and good fishing and boating. |
| Lakeshore Capacity Study: Part I—Test of Effects of Shoreline Development on the Trophic Status of Lakes | P. J. Dillon; W. A. Scheider; R. A. Reid; D. S. Jeffries | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 121 - 129 | Lakeshore Capacity Study: Part I—Test of Effects of Shoreline Development on the Trophic Status of Lakes | A simple mass balance model, combined with detailed hydrologic and mass balance measurements, yielded accurate predictions of total phosphorus (TP) concentrations in two lakes with no shoreline development. On the other hand, the model based on only natural TP loads predicted TP concentrations lower than observed in four developed lakes; however, in three of the four lakes, predictions and observations were virtually identical if the potential TP contribution from sewage disposal systems associated with shoreline development was included in the budgets. In the exception Harp Lake, the only one of the four with thick deposits of till/soil in its catchment, predicted and observed trophic status were comparable if about a third of the potential TP input from shoreline development reached the lake. The suggestion is that in this case the till/soil was effective in retaining a significant portion of TP transported from septic systems. Lakes with oxic and anoxic hypolimnia were distinguished by using different apparent settling velocities in the TP mass balance model. A lower settling velocity in those lakes with anoxic hypolimnia is consistent with TP release from the sediments under these conditions. |
| Aeration of Stratified Lakes: Theory and Practice | Robert W. Kortmann; George W. Knoecklein; Charles H. Bonnell | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 99 - 120 | Aeration of Stratified Lakes: Theory and Practice | Layer aeration (U.S. Pat. 4,724,086) can be described as a depth-discrete artificial circulation technique. Like destratification, it uses both photosynthetic and diffusional sources of oxygen to overcome oxygen demand. Like hypolimnetic aeration, it maintains necessary vertical temperature structure for coldwater fish and zooplankton refugia. Layer aeration alters thermal structure, creating several functional thermoclines, while retaining stratification stability. Persistent metalimnetic anoxia and increased eddy diffusional transport across the thermocline, common problems with hypolimnetic aeration, are overcome by layer aeration. A 7-year study was conducted to demonstrate aeration efficiency, ecosystem response, and water supply benefits from layer aeration of a 212 ha (523 acre), 21 m (70 ft) deep, eutrophic water supply lake using two 30 HP compressors. Aerator oxygen input was a function of influent dissolved oxygen (DO) and temperature. Oxygen input efficiencies ranged from 2% to 13% m-1. Redistribution of available DO during layer aeration essentially doubled oxygen input, reaching a maximum of over 99% efficiency compared to the oxygen content of compressed air. Specially designed air-water separators increased oxygen input of both hypolimnetic and layer aerators (by 1-2% m-1). The ecosystem response to layer aeration occurred in several annual stages. Overall summer Secchi disk transparency increased from <1.8 m (<6 ft) to >4.6 m (>15 ft) due to elimination of Cyanobacteria blooms. Descent of compensation depth into the hypolimnion contributed to restoration of 2.5 106 m3 (2000 acre-ft) salmonid habitat and an additional 1.6 106 m3 (1300 acre-ft) zooplankton refugia. Large-bodied Cladocera (Daphnia sp.) returned as a dominant zooplankton population in 1990. Deep nitrification increased, and the ecosystem respiratory quotient (ERQ) decreased from 1.51 to 1.14, indicating a shift in respiratory processes from anaerobic to aerobic. Water supply benefits included elimination of prechlorination, extended granulated activated carbon (GAC) bed longevity, avoidance of taste and odor episodes, and reduced treatment cost. Aeration system sizing, the ammonia anomaly, and ecosystem energetics are discussed relative to ecosystem responses to aeration. |
| Lake Ecosystem Energetics: The Missing Management Link | Robert W. Kortmann; Peter H. Rich | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 77 - 97 | Lake Ecosystem Energetics: The Missing Management Link | Phosphorus plays a central role in the bioenergetics of organisms and ecosystems (recall Adenosine Triphosphate [ATP], substrate level phosphorylation, cyclic and noncyclic photophosphorylation). It is a role which no other atom can duplicate. Phosphorus is of paramount importance in lake management because it most often limits the degree of phytoplanktonic autotrophy (algae growth). However, many other aspects of lake ecosystem structure and function offer substantial promise for the future of lake management and restoration. One such aspect, ecosystem energetics, is too often neglected or misunderstood by the lake manager. There are fundamental differences between autotrophication and allotrophication, trophic and detrital dynamic structures, eutrophication and lake succession, and how these ecosystem components and processes can be effectively managed. An understanding of the nitrogen, sulfur, iron, and phosphorus cycles of lakes yields insight into new restoration technologies (e.g., alum surrogates, anaerobic aeration, biomanipulation) and potential long-term impacts of existing methods (sulfate loading, copper sulfate, aluminum sulfate). Methods to control eutrophication, and its in-lake consequences, are directly related to the energetics of a lake ecosystem, as are treatments of symptoms. Lakes are complex ecosystems in which all living organisms interact collectively with physical and chemical processes of the environment. Understanding a lake ecosystem is understanding nature, and will lead to more effective stewardship of the ecosystem in which we play a major role. This introduction to lake ecosystem energetics is intended to illustrate some fundamental relationships among biology, ecology, physics, chemistry, and lake management. |
| The Grazing Impact of Daphnia parvula on Phytoplankton in a Southeastern, Eutrophic Reservoir | Thomas D. Shahady; Samuel C. Mozley; Donald E. Francisco | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 189 - 203 | The Grazing Impact of Daphnia parvula on Phytoplankton in a Southeastern, Eutrophic Reservoir | Zooplanktonic grazing is increasingly recognized as an important component of phytoplankton dynamics and composition in natural, north-temperate lakes. The most efficient grazers are species of the cladoceran genus Daphnia, but in southeastern reservoirs this genus is often sparse in abundance, particularly during summer. Further, the dominant daphnia is Daphnia parvula which is a small-bodied species possibly not capable of exerting similar controls on food resources as larger Daphnia species. Experimental exclosure of fishes from zooplankton in Jordan Lake, a eutrophic, 55 km2 reservoir in Piedmont North Carolina, was undertaken to determine if zooplankton would respond sufficiently to influence phytoplankton. Every major crustacean zooplankton taxon doubled its biomass within 2 weeks after protection from predators in at least 1 of six experiments from May to September. The usual numerical dominant, Skistodiaptomus pallidus, increased in every test by at least two-fold. D. parvula increased in four of the tests and rapidly reduced chlorophyll concentrations in each case. Abundance and associated species changes in phytoplankton were negligible without a Daphnia response, but when Daphnia increased cell densities of all taxa including most blue-green algae decreased. Only Anabaena increased in proportion to total phytoplankton units. When these results were examined in a D. parvula grazing model, output suggested phytoplankton declines could be caused solely by increased grazing pressure. These results strongly suggest that fish predation is severely limiting the grazing power of zooplankton in Jordan Lake. |
| Measuring Chlorophyll and Phaeophytin: Whom Should You Believe? | Richard P. Axler; Christopher J. Owen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 143 - 151 | Measuring Chlorophyll and Phaeophytin: Whom Should You Believe? | Comparisons of chlorophyll and phaeophytin measurements performed on field and laboratory cultures of algae showed that fluorometric analyses were comparable to the standard spectrophotometric method over a wide range of phaeophytin, chlorophyll, and chlorophyll-b:chlorophyll-a values. Inaccurate phaeophytin measurements obtained using a commercially available fluorometer were attributable to an incorrect narrow bandpass excitation filter which can now be replaced by the company. Differences in filtration and extraction technique and in frozen storage time did not result in significant changes in pigment estimates. |
| Impact of Lime on Sediment Phosphorus Release in Hard water Lakes: the Case of Hypereutrophic Halfmoon Lake, Alberta | J. Babin; E. E. Prepas; T. P. Murphy; M. Serediak; P. J. Curtis; Y. Zhang; P. A. Chambers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 2 | 1994 | 131 - 142 | Impact of Lime on Sediment Phosphorus Release in Hard water Lakes: the Case of Hypereutrophic Halfmoon Lake, Alberta | Halfmoon Lake is a small, moderately deep, hypereutrophic, hardwater lake with a relatively small (2.4 km2), partially cleared drainage basin situated in the Boreal Mixedwood Ecoregion of central Alberta. The water is often thermally stratified, and average residence time is 60 years. During mid- to late summer 1988 and 1989, 188 metric tons of Ca(OH)2 and 58 metric tons of CaCO3 were applied to the surface of Halfmoon Lake to decrease total phosphorus (TP) concentration and algal biomass (estimated as chlorophyll a [Chl a]). Mean summer (July-September) Chl a and TP in the euphotic zone in 1989 and 1990 decreased to 53 and 63%, respectively, of the pretreatment year (1982). Similarly, sediment P release from June through August was 50% lower in 1989 and 1990 than in the pretreatment year. In contrast water quality deteriorated in three nearby reference lake basins, also hypereutrophic, so that average summer euphotic zone Chl a and TP were 217 and 116% higher, respectively, in 1989 and 1990 than in 1982. When these trends were considered, posttreatment corrected Chl a and TP in Halfmoon Lake were 24 and 54%, respectively, of pretreatment values. Decreased summer Chl a in Halfmoon Lake was associated with higher winter dissolved oxygen (DO) concentrations, presumably due to a decrease in the oxygen demand in the water column at fall overturn following treatment and hence increased DO at freeze-up. Thus, Halfmoon Lake, a traditional winterkill lake where the water column went completely anoxic by January, had sustainable DO for fish in the posttreatment winters. We further hypothesize that enhanced sediment calcium content was responsible for reduced P loading from bottom sediments during winter and, consequently, lower summer Chl a. |
| Limnology Of Missouri Reservoirs: An Analysis of Regional Patterns | John R. Jones; Matthew F. Knowlton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 17 - 30 | Limnology Of Missouri Reservoirs: An Analysis of Regional Patterns | Data from 94 Missouri reservoirs demonstrated a large interregional variation in total phosphorus (TP), total nitrogen (TN), algal chlorophyll (Chl), and suspended solids among the four physiographic provinces with numerous reservoirs. The interprovincial pattern for nutrients, algal biomass, and mineral turbidity was Ozark Highlands < Ozark Border ≃ Glacial Plains < Osage Plains corresponding to an interregional gradient between forest and agriculture as the dominant land cover. On the basis of TP most Missouri reservoirs were eutrophic (61%) or mesotrophic (21%) with few hypereutrophic (7%) or oligotrophic (11%). Statewide, water clarity was low (median Secchi depth 1.0 m) and more strongly related to non-volatile suspended solids (NVSS, R2 = 0.80) than algal Chl (R2 = 0.30). Summer mean values showed a curvilinear relation between Chl and TP (log10 transformed) reaching an asymptote above ≃ 50 μg/L TP/L — a range where most reservoirs have high NVSS and low TN:TP. Nitrogen limitation, light limitation, or binding of phosphorus by non-algal suspended material may explain reduced Chl:TP ratios in turbid reservoirs. Survey data, however, do not distinguish the roles of differing limiting nutrients and light limitation in reservoirs with > 10 mg NVSS/L. Conventional lake management scenarios based on phosphorus control seem appropriate for Missouri reservoirs of low to moderate turbidity. |
| Consequences of Selecting Incorrect Hydrologic Parameters When Using the Walker Pond Size and P8 Urban Catchment Models | John C. Panuska; Joel G. Schilling | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 73 - 76 | Consequences of Selecting Incorrect Hydrologic Parameters When Using the Walker Pond Size and P8 Urban Catchment Models | The Walker Pond Size Model is a widely used spreadsheet approach to the design of storm water treatment ponds. The user inputs the Soil Conservation Service curve number for the pervious areas and the fraction of impervious area. Input parameters must be correctly determined by the user. One commonly made error is to enter the weighted curve number in place of the pervious curve number, which can result in overestimation of dead storage volume by as much as 8.89 mm (0.35 inch). Using the weighted curve number only and not the model's equation can underestimate the required volume as much as 19.56 mm (0.77 inch). Proper use of the Walker Model is essential to obtain a beneficial, cost-effective design. |
| Decomposition of Desiccated Submersed Aquatic Vegetation and Bioavailability of Released Phosphorus | Forrest E. Dierberg | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 31 - 36 | Decomposition of Desiccated Submersed Aquatic Vegetation and Bioavailability of Released Phosphorus | In-situ decomposition and P release (litter bags) in Lake Okeechobee for Vallisneria, Hydrilla, and Potamogeton followed a simple exponential decay model. Vallisneria and Hydrilla decomposed at rapid rates (k = 32-42/yr) so that only 9-14% of initial dry wt remained after 3 weeks; Potamogeton decomposed at a rate of 9.9/yr with 57% of the dry wt remaining during this period. Phosphorus was readily mobilized from decomposing plants: rates of phosphorus loss were 37.2, 25.2, and 9.1/yr for Hydrilla, Vallisneria, and Potamogeton, respectively (>75% of initial phosphorus was lost after 3 weeks for Hydrilla and Vallisneria). Laboratory experiments confirmed that the loss of phosphorus from desiccated submersed aquatic vegetation is fast (within 4 hr) and readily bioavailable. Yield coefficients of 564-665 mg dry wt of algal cells (Selenastrum) or 1.4-5.6 mg chlorophyll a per mg P released were obtained. |
| Summer Fluctuations in Planktonic Chlorophyll a Concentrations in Lake Okeechobee, Florida: The Influence of Lake Levels | Michael J. Maceina | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 1 - 11 | Summer Fluctuations in Planktonic Chlorophyll a Concentrations in Lake Okeechobee, Florida: The Influence of Lake Levels | During summer (May-October), a positive relationship was evident between lake water levels and chlorophyll a concentrations in littoral and littoral:pelagic interface regions of Lake Okeechobee. High water levels in synergy with the large size (1830 km2), shallow depth (Zx = 2.7 m), and unique bottom configuration of Lake Okeechobee appeared to facilitate greater horizontal mixing and circulation which resulted in higher phosphorus concentrations in a portion of the littoral zone. In shallow littoral regions where light penetration was sufficient, an empirical link between phosphorus and chlorophyll a was evident. East-to-west and north-to-south gradients of phosphorus extended from hard-bottom littoral regions to the open-water pelagic zone located over soft, phosphorus-laden flocculent muds, and these gradients were more pronounced at low lake levels. Phosphorus loading from tributaries only affected algal concentrations in a small portion of the lake. A higher water level regulation schedule was implemented in 1978 to augment water supplies and this increased lake levels when precipitation was sufficient. A slightly lower lake level regulation schedule might reduce the frequency of hypereutrophic algal blooms in nearshore and littoral areas. |
| Analysis of Summer Phosphorus Fluxes Within the Pelagic Zone of Eau Galle Reservoir, Wisconsin | William F. James; John W. Barko | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 61 - 66 | Analysis of Summer Phosphorus Fluxes Within the Pelagic Zone of Eau Galle Reservoir, Wisconsin | Major phosphorus (P) fluxes to and from the pelagic zone (i.e., open water region including epilimnion, metalimnion, and hypolimnion) were estimated from data collected over a 6 year period during the summer in Eau Galle Reservoir, Wisconsin. P inputs to the pelagic zone included profundal sediments, the watershed, groundwater, and transport of P from the littoral zone. P outputs from the pelagic zone included discharge from the reservoir, deposition, and transport of P to the littoral zone. Nighttime convective circulation was assumed to be the dominant mechanism of P exchange between the littoral and pelagic zones. Littoral P inputs, often neglected from budgetary analyses, accounted for 15% of the total measured P input and 25% of the internal P input to the pelagic zone. External P inputs were greatest, accounting for 42% of the total measured P input to the pelagic zone. These results emphasize the need for control of various sources of P inputs in the development of lake and reservoir management strategies. |
| Alum and Nitrate as Controls of Short-Term Anaerobic Sediment Phosphorus Release: An In Vitro Comparison | Curtis L. DeGasperi; Dimitri E. Spyridakis; Eugene B. Welch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 49 - 59 | Alum and Nitrate as Controls of Short-Term Anaerobic Sediment Phosphorus Release: An In Vitro Comparison | A laboratory comparison of the effectiveness of two sediment phosphorus (P) inactivation techniques (aluminum sulfate and calcium nitrate) was made using intact sediment cores collected from Green Lake, WA. Additional treatments with Na2S, NaOH, and glucose were performed to assess effectiveness of the treatments under conditions of 1) reduced availability of Fe, 2) increased pH, and 3) organic matter enrichment, respectively. Under warm, dark, quiescent conditions both aluminum sulfate (alum) and calcium nitrate (nitrate) were equally effective in controling P release from the sediments when compared to a control. Addition of Na2S resulted in an increase in P release, but again alum and nitrate were equally effective compared to the control. Addition of NaOH resulted in an increase of P release, but alum was not as effective as nitrate in controling P release, possibly due to pH sensitivity of the aluminum hydroxy-P complex. Addition of glucose resulted in an increase of P release, perhaps due to increased gas evolution, but nitrate was not as effective in controling P release, possibly due to the availability of nitrate for degradation of organic matter and subsequent release of methane and nitrogen gas. Sediment oxygen demand (SOD) of Green Lake sediments was determined to be much less than that of sewage polluted Lake Lillesjn, Sweden, and similar to the SOD of Lake Lillesjn sediments following nitrate treatment. Sediment profiles of Fe, Mn, P, N, S, water content, and organic matter suggest that anaerobic processes were operational in the sediments. Although a recent study indicates that the overlying water does not experience episodes of reduced oxygen content, and that much of the water column increase in P can be attributed to migrating phytoplankton (primarily Gloeotrichia echinulata), possible links between sediment chemical and microbial processes and P uptake by benthic stages of phytoplankton at the sediment-water interface have not been investigated. More well planned and monitored in-lake treatments or limnocorral experiments of both alum and nitrate are needed to improve our predictions of the effectiveness and longevity of these two chemical treatments. |
| Detecting the Increased Eutrophication Rate of Douglas Lake, Michigan: the Relative Areal Hypolimnetic Oxygen Deficit Method | Owen T. Lind; Laura Dávalos-Lind | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 67 - 71 | Detecting the Increased Eutrophication Rate of Douglas Lake, Michigan: the Relative Areal Hypolimnetic Oxygen Deficit Method | We use data gathered since 1971 on Douglas Lake, Michigan to illustrate the use of temperature and depth adjusted oxygen deficits to assess changes in the rate of lake eutrophication. The method of calculation with adjustments is presented. By comparing different hypolimnia in the multidepression lake, we show that localized lakeshore land use produces regional patterns of production that are detected by comparison of oxygen deficits. For some lake regions, the increase in oxygen deficit has had a linear doubling since 1971. Using historical data, this rate of change is much greater than for the previous 50 years. The oxygen deficits in the lake region farthest from lakeshore development averaged 60% of those in the region nearest lakeshore development. |
| Lake Patzcuaro, Mexico: Watershed and Water Quality Deterioration in a Tropical High-altitude Latin American Lake | Arturo Chacón Torres | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 37 - 47 | Lake Patzcuaro, Mexico: Watershed and Water Quality Deterioration in a Tropical High-altitude Latin American Lake | Lake Patzcuaro is a tropical, high-altitude, freshwater lake (130 km2 surface area) located on the Mexican plateau. The lake originated from tecto-volcanic processes associated with the Mexican Neovolcanic Axis. Maximum depth (12 m) occurs in the northern part of the lake, whereas shallow areas are developing in the south. Its indigenous fish fauna and the presence of P'urhpecha Indian settlements around its shoreline identify Lake Patzcuaro as a unique natural resource having ecological, historical, and cultural value. The lake is endorheic and the annual water balance is controlled by differences among rainfall, seepage, watershed runoff, and evaporation. A mass-balance model indicates that hydrologic inputs from the watershed are being reduced as a result of watershed deterioration. High turbidities result from volcanic silt, raw sewage, and increasing erosion loads to the lake. Lake Patzcuaro is light-limited due to scattering and attenuation from suspended inorganic materials. The lake has high concentrations magnesium, sodium, carbonates, total phosphorus, chlorophyll a, and suspended solids. Lake Patzcuaro is mostly eutrophic with some less productive areas. Proposed lake management strategies focus on the watershed and include: erosion control and reforestation, basin-wide sewer systems and wastewater treatment, and preservation of the indigenous fishery. |
| Testing Models of Chlorophyll and Transparency for Midwest Lakes and Reservoirs | Matthew F. Knowlton; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 8 | 1 | 1993 | 13 - 16 | Testing Models of Chlorophyll and Transparency for Midwest Lakes and Reservoirs | Seasonal means of chlorophyll (Chl), total phosphorus (TP), total and non-volatile suspended solids (TSS, NVSS), and Secchi depth from 28 reservoirs and natural lakes in Iowa, Kansas, and Oklahoma were used to test predictions of log-log regression models developed from Missouri reservoirs by Jones and Knowlton (1993). Water-bodies in Iowa, Kansas, and Oklahoma exhibited a curvilinear relation between log-Chl and log-TP similar to that for Missouri reservoirs. These data fit the Missouri regressions for Chl-TP and Chl-(TP NVSS) fairly well; although the Missouri models usually underpredicted Chl for Iowa waterbodies. Missouri models provided an excellent fit to outstate transparency data. |
| Assessing Nonpoint Phosphorus Control in the LaPlatte River Watershed | Donald W. Meals | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 2 | 1993 | 197 - 207 | Assessing Nonpoint Phosphorus Control in the LaPlatte River Watershed | Phosphorus loading from agricultural activities such as manure and fertilizer applications often contributes to eutrophication of surface waters. The primary goal of the LaPlatte River Watershed Project in northwestern Vermont was to reduce phosphorus loading from farmland through implementation of best management practices (BMPs). Eleven years of monitoring did not show a dramatic decrease in phosphorus concentration or load from the watershed. However, analysis controlling for hydrologic variability suggested significant decreases in phosphorus load from some subwatersheds following completion of the land treatment program. Post-BMP phosphorus load reductions of 26-44% (0.01-0.14 kg/ha/yr) were estimated using a paired regression technique that accounts for discharge differences between years. Phosphorus export was reduced under most circumstances, except under the highest runoff conditions, suggesting that the capacity of the land treatment system to control phosphorus may have been exceeded occasionally. Observed phosphorus reductions in treated watersheds appeared to be related to the degree of treatment after a minimum threshold level of land treatment had been achieved. |
| Paleolimnological Methods for Defining Target Conditions in Lake Restoration: Florida Case Studies | Mark Brenner; Thomas J. Whitmore; Michael S. Flannery; Michael W. Binford | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 2 | 1993 | 209 - 217 | Paleolimnological Methods for Defining Target Conditions in Lake Restoration: Florida Case Studies | Paleolimnological methods can be used to identify baseline limnological conditions and to assess anthropogenic changes in lakes that lack historical limnological data. We studied a suite of Florida lakes and developed regression models that predict limnetic total P and Chi a from diatom assemblages and nutrient accumulation rates in surface sediments. These models were applied to a 210Pb-dated sediment core from Lake Parker, Polk County, Florida, and a pollen-dated profile from Lake Francis, Highlands County, Florida, to infer historical water quality. Our results show that Lake Parker displayed statistically significant increases in limnetic total P and Chi a concentrations since the 1920s. Lake Francis has been eutrophic for more than 2 millennia, but shows a statistically significant decrease in limnetic total P during the present century. This study demonstrates that lakes may be naturally productive because of edaphic influences and may respond differently to human disturbance. We conclude that paleolimnological estimates of predisturbance nutrient/Chi a concentrations can help define target conditions for water quality restoration programs. |
| Submersed Macrophyte Vegetation and Distribution Within Lakes: Line Transect Sampling | John E. Titus | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 2 | 1993 | 155 - 164 | Submersed Macrophyte Vegetation and Distribution Within Lakes: Line Transect Sampling | Line transects often provide a practical basis for quantitative, nondestructive sampling of aquatic vegetation; here four types of line transect arrangements are briefly compared: 1) transects perpendicular to the shoreline have been widely used, but may oversample nearshore areas where shorelines are convex; 2) transects parallel to each other at regular intervals may provide the best basis for mapping an area; but 3) parallel transects at (stratified) random intervals may reasonably represent different areas within the site and avoid possible biases of regular sampling. The tendency of all three methods to oversample some depth ranges and to combine data from different community types may be obviated by using 4) transects along depth contours near a given shoreline of nearly uniform exposure. Line transects may in some cases be sampled with a line intercept method, which is probably best suited for floating-leaved species, but most often a belt transect consisting of contiguous quadrats is more practical. For each sampling unit, data may be gathered on species presence or percent cover, although the former may yield more information per unit effort. Five field examples are given to illustrate sampling schemes, macrophyte community heterogeneity, and straightforward data summary procedures. |
| Biomass Techniques for Monitoring and Assessing Control of Aquatic Vegetation | John D. Madsen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 2 | 1993 | 141 - 154 | Biomass Techniques for Monitoring and Assessing Control of Aquatic Vegetation | Biomass quantification techniques are widely used in research on aquatic vegetation, but less often applied to monitor aquatic vegetation or assess specific control techniques. The application of these techniques to both assessing nuisance problems, and evaluating control tactics is discussed using case histories. The proper methods for developing a sampling regime, locating sample points, collecting samples, and analyzing data are reviewed. Critical factors such as quadrat size and sample frequency and number are discussed in depth. The purpose of biomass sampling programs within the context of management plans is to tailor the level of effort to the scale of the management effort, and to appropriately assess or predict effects of the management tactics utilized. |
| Aquatic Vegetation Quantification Symposium: An Overview | John D. Madsen; Jay A. Bloomfield | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 2 | 1993 | 137 - 140 | Aquatic Vegetation Quantification Symposium: An Overview | A symposium was held at the 10th annual meeting of the North American Lake Management Society to discuss methods of aquatic vegetation quantification and its application to an aquatic plant management program. Topics discussed at this symposium included the importance of accurate taxonomic identifications, the use of transect and biomass sampling methods, development of manipulative experiments to evaluate management techniques, and advances in remote sensing for aquatic plant quantification. These technical approaches were then illustrated in an ongoing governmental aquatic plant management program. Techniques used for aquatic plant quantification and the importance of vegetation quantification to an ongoing management program are summarized. |
| Application of Aquatic Vegetation Identification, Documentation, and Mapping in Eurasian Watermilfoil Control Projects | Peter R. Newroth | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 2 | 1993 | 185 - 196 | Application of Aquatic Vegetation Identification, Documentation, and Mapping in Eurasian Watermilfoil Control Projects | Management of Eurasian watermilfoil (Myriophyllum spicatum L.), which was introduced to British Columbia, Canada, about 1970, incorporates various technologies and approaches. Monitoring of Eurasian watermilfoil since 1972 has required development of phytochemical means to distinguish Myriophyllum taxa, extensive and often repeated surveys of over 1500 lakes, and establishment of a large herbarium and database. Field survey methods have been used extensively to evaluate control procedures, measure rates of plant population change, document and map the spread of Eurasian watermilfoil and its impacts, and provide data to plan annual management. Survey methods used are described and examples of the results are presented to illustrate the application of field survey data to guide decision making and allocation of resources. |
| Taxonomic Considerations in Aquatic Vegetation Assessments | C. Barre Hellquist | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 2 | 1993 | 175 - 183 | Taxonomic Considerations in Aquatic Vegetation Assessments | Correct identification of vascular aquatic plants is extremely important when studying waters for various management policies. The plants should be thoroughly examined by a person familiar with aquatic flora who is able to interpret technical botanical keys, because many taxa are similar in appearance. Misidentification often leads to possible eradication of an important or rare species from a body of water. Voucher specimens should be collected from the area studied. These specimens must be recorded in field notes, pressed as soon as possible, and then properly identified. Complete data should include such things as associated plants, water characteristics, and a detailed location description. A good library of various field manuals and the use of a herbarium are very helpful in making correct identifications. Specimens should be placed in a herbarium collection at a location that is easily accessible, such as a university or state agency. Voucher sheets serve as valuable documentation that may show the shifts in plant populations over a period of time. These specimens may be of extreme importance in legal hearings that may arise from proposed work. |
| Experimental Design and Analysis in Field Studies of Aquatic Vegetation | David F. Spencer; Linda C. Whitehand | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 2 | 1993 | 165 - 174 | Experimental Design and Analysis in Field Studies of Aquatic Vegetation | Field experiments may be useful for researchers and managers concerned with aquatic plants. Since experimental design and statistical analysis are closely related, this paper discusses statistical and practical considerations for conducting and evaluating field experiments with aquatic plants. Special emphasis is given to the analysis of variance, assumptions required for its use, and concepts related to it (e.g., statistical power, means comparison procedures, treatment structure, pseudoreplication, etc.). The paper concludes with a brief introduction to papers in the literature which illustrate the use of field experiments for studying aquatic plants. |
| Physiological Characteristics of Vertically-Stratified Lyngbya wollei Mats | Barbara J. Speziale; E. Glenn Turner; Larry A. Dyck | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 107 - 114 | Physiological Characteristics of Vertically-Stratified Lyngbya wollei Mats | Massive floating and benthic mats of the filamentous blue-green alga, Lyngbya wollei, occlude small lakes and shallow coves of large reservoirs, especially in the southeastern United States. In situ standing crops (up to 6.66 kg fresh weight m-2), seasonal vertical distribution (surface, benthic and mid-depth suspended) and metabolic characteristics of L. wollei mats in Marten's Pond, S.C. are described and compared with midsummer infestations in three other southeastern impoundments. The dense floating mats which are the most visible manifestation of infestations limit irradiance available to subsurface filaments; less than 2% of incident irradiance penetrates surface mats. Surface filaments containing minimal chlorophyll a and abundant myxoxanthophyll are photosynthetically inactive, whereas subsurface filaments having greater concentrations of phycobilins and chlorophyll a are most active in photosynthesis. L. wollei is perennial because virtually all of the summer biomass overwinters on the lake sediments. The bulk of L. wollei biomass (> 64%) in Marten's Pond remained subsurface throughout the year. L. wollei persists and grows in this subsurface environment due to the abundant phycobilin pigments, adapted for interception of a broad spectrum of low intensity light and the low photosynthetic light compensation point (32 μ Einsteins m-2 sec-1) of healthy filaments. |
| The Role of Socio-Economic Determinants in Lake Management in Developing Countries | Jeffrey A. Thornton; Walter Rast; Sven-Olof Ryding | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 115 - 120 | The Role of Socio-Economic Determinants in Lake Management in Developing Countries | The compilation of international handbooks on the management of eutrophication and nonpoint source pollution posed a number of conceptual problems, not the least of which was the determination of relevant and meaningful methods to span the spectrum of developed and developing world applications. Given that most of the lake management strategies currently being employed throughout the world are based in whole or in part on methods developed in Europe or North America, this problem is a significant one. Not only are there measurable limnological differences between waterbodies in the temperate zone versus waterbodies in the tropics/subtropics, but also differences in the levels of technical skills and “hardware†exist between these regions. Many developing countries suffer badly from loss of skills to the developed world and must buy goods and services in the field of lake management. Hence, to be successful, both the investigations and implementations must take cognizance of the climatic and techno-socio-economic rigors imposed by the developing world setting. This paper briefly reviews some of the distinguishing characteristics of society and waterbodies in the tropical developing countries, before examining a selection of appropriate strategies for managing eutrophication, using illustrative examples from southern Africa. Such strategies could also have application to small scale projects in the developed world where similar cost constraints often apply. |
| Satellite Mapping of Suspended Sediment and Its Application to Reservoir Assessment | John D. Ross; Frank R. Schiebe; John A. Harrington Jr.; Herbert J. Grimshaw | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 89 - 95 | Satellite Mapping of Suspended Sediment and Its Application to Reservoir Assessment | Lake Thunderbird, a 2428 hectare reservoir located in Norman, Oklahoma, was studied along with 15 other lakes in south central Oklahoma over a two year period. An objective of this study was continued development and testing of satellite-based capabilities to assess the water quality variations within reservoirs. To accomplish this goal, lake measurements and water samples were obtained on each day of Landsat overpass. A mathematical model of the relationship between suspended sediment and reflectance measured by the satellite was calibrated to the 16 south central Oklahoma lakes. A series of multi-date suspended sediment maps was generated for Lake Thunderbird with this model using Landsat MSS near infrared (Band 3) data. These maps were used to quantitatively evaluate the geographic extent of suspended sediment on each date investigated. The results demonstrate the feasibility of using Landsat data to routinely monitor and assess surface water bodies impacted by suspended sediment. |
| The Effects of Analytical Variations on Estimates of Phosphorus Concentration in Surface Waters | Sara J. Griesbach; Robert H. Peters | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 97 - 106 | The Effects of Analytical Variations on Estimates of Phosphorus Concentration in Surface Waters | Systematic variations in methods for the storage, digestion and measurement of lake water samples for phosphorus determinations show that these methods are very robust. Frozen samples can be kept for at least one year without any detectable change in total phosphorus, [TP], but the concentrations of P subfractions may change. Variations in the amount of oxidant (0.05 to 0.8 g potassium persulphate/40 ml sample), in the duration (10-90 min), or pressure (100 vs 200 k Pa) of oxidation, and in the amount of sample lost in autoclaving had no effect on estimated [TP]. The exact composition of acid molybdate “mixed reagent†also proved not to be critical, for when each of the components was varied in turn, similar results were obtained with 5 to 10 g ammonium molybdate, 2.5 to 20 g ascorbic acid, 0.025 to 0.4 g potassium antimony tartrate and 55 to 100 ml sulphuric acid per liter of mixed reagent. No significant difference was obtained by varying the amount of mixed reagent from 1 to 7.5 ml/40 ml sample, so some economy may be achieved by reductions in the amount of reagent used. Colour development was stable for up to 8 hours after reagent addition. Refrigerated mixed reagent was stable for up to 48 h, and ascorbic acid solution for 72 h, although storage appeared to increase variation. The insensitivity of this analysis to substantial variations no doubt contributes greatly to the method's success. |
| Cost-Effective Monitoring Using Lay Volunteers on Shipshewana Lake | Janis S. Markusic | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 126 - 131 | Cost-Effective Monitoring Using Lay Volunteers on Shipshewana Lake | High resolution, site specific tributary and lake water column data are required for the model calibration and verification phase of the Shipshewana Lake restoration project in north-central Indiana. The collection of these data would be prohibitively expensive without local commitment in the form of a lay monitoring program. Lay volunteers were trained in the operation of basic limnological instrumentation, sample collection, data recording, and sample shipping. Monitoring consisted of bi-monthly water quality monitoring and sampling at 11 stations in the lake and its tributaries, along with storm samples collected at 11 stations throughout the watershed. A total of 551 water samples were targeted for collection over a 12 month period. The results of the first six months of monitoring are presented along with a summary of cost-savings, difficulties encountered, and keys to the success of this program. |
| Evaluation of an Institutional Framework Designed to Retard Cultural Eutrophication | Lloyd L. Eagan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 131 - 136 | Evaluation of an Institutional Framework Designed to Retard Cultural Eutrophication | Lakes in Dane County suffer from cultural eutrophication. Many attempts designed to solve water quality problems have failed. While technical solutions appear feasible, institutional arrangements have hampered progress in pushing back the clock on cultural eutrophication. The latest effort to address these institutional weaknesses produced the Dane County Lakes and Watershed Commission. At the same time, the County was also provided with new authority and financing tools for water resource problems. The effectiveness of the new Commission and the powers granted to the Dane County Board of Supervisors are evaluated in terms of seven lake management factors. The new arrangements appear to address six out of these seven factors fairly well. While the new institution offers much promise, the County faces the challenge of sustaining the political will to make long-term progress in reversing cultural eutrophication. |
| Watershed Protection & Compliance with the Safe Drinking Water Act Amendments | Eileen Pannetier | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 120 - 123 | Watershed Protection & Compliance with the Safe Drinking Water Act Amendments | |
| Developing a Rigorous Water Quality Database Through a Volunteer Monitoring Network | Richard P. Maas; Darlene J. Kucken; Peter F. Gregutt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 123 - 126 | Developing a Rigorous Water Quality Database Through a Volunteer Monitoring Network | Lake and reservoir managers, as well as affected citizen groups, have increasingly recognized the need for extensive watershed-level land use and water quality data in developing effective lake management strategies. Water quality data, in particular, from lake or reservoir tributaries is essential for identifying and quantifying point and nonpoint sources of pollutants. The realization of these informational needs, coupled with the personnel and financial resource constraints that limit most governmental agency monitoring programs, have helped to spawn a multitude of citizen-organized volunteer water quality monitoring programs. This paper describes a unique volunteer-based monitoring network, which in cooperation with a university laboratory, is developing laboratory monitoring data using EPA-certified methods at minimal cost. The program consists of 45 stream sites, each of which is staffed by two or more volunteers. The network is sampled monthly for 12 parameters including various nutrients and heavy metals. This program appears to have the unique capacity of providing STORET-acceptable data while simultaneously functioning as a highly visible quality education/awareness program within the local community. |
| A Phosphorus-Fish Standing Crop Relationship For Streams? | Mark V. Hoyer; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 25 - 32 | A Phosphorus-Fish Standing Crop Relationship For Streams? | Total fish standing crop data from 79 North American streams located in Wyoming (N = 20), Vermont (N = 19), Florida (N = 15), Iowa (N = 12), Ontario (N = 10), Washington (N = 2), and Missouri (N = 1) were used to test the hypothesis that stream fertility as indexed by total phosphorus concentrations is an important environmental factor influencing fish standing crop. Total fish standing crop among the different geographical regions was not related to differences in latitude, but regional estimates of average fish standing crop were significantly correlated to total phosphorus concentrations (r = 0.79, p < 0.05, n=7). The best-fit empirical regression model for these data was: log (TFSC) = 0.59 log (TP) + 0.82, where TFSC is total fish standing crop (kg/hectare) and TP is total phosphorus concentration (μg/L). The phosphorus-total fish standing crop relationship, however, was weaker when fish standing crop data from individual streams were correlated to total phosphorus concentrations (r = 0.42, p < 0.05, n=79). Locally weighted robust regression analysis (LOWESS) indicated that the phosphorus-total fish standing crop relationship was not linear. Total fish standing crop increased with total phosphorus concentrations throughout the range of reported values, but the increase was much more rapid in streams having total phosphorus concentrations ≤ 15 μg/L. This is consistent with the results of whole-stream fertilization experiments that have demonstrated that phosphorus enrichment enhances autotrophic production in nutrient-deficient streams. The phosphorus-total fish standing crop relationsip also is consistent with the long-held hypothesis that stream fertility is an important factor influencing fish standing crop in North American streams. |
| Response of Periphyton to Nutrient Enrichment in Lake Chelan, WA | Jean M. Jacoby; Debra D. Bouchard; Clayton R. Patmont | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 33 - 43 | Response of Periphyton to Nutrient Enrichment in Lake Chelan, WA | Enhanced growth of periphyton (primarily attached algae) is an early indicator of nutrient enrichment in lakes. Periphyton abundance, composition, and spatial distribution were examined in ultra-oligotrophic Lake Chelan, Washington to characterize relationships to nutrient inputs. The wide range in the nutrient content of tributaries discharging to Lake Chelan provided a unique opportunity to evaluate nearshore periphyton development in relation to nutrient concentration while minimizing the interference of other potentially controlling factors (e.g., light, temperature, substrate, wave energy). Periphyton samples were quantitatively collected during summer 1987 from rocks located in nearshore areas at discrete distances from five tributaries. The distribution of tributary waters was assessed using specific conductance as a tracer. Compared to stations distant from the nutrient-rich tributaries, high periphyton biomass (50-216 mg chlorophyll a/m2) with a greater proportion of filamentous algae was generally found at stations influenced by the tributary plumes. |
| Environmental Monitoring and Assessment Program, EMAP–Surface Waters: A Northeast Lakes Pilot | David P. Larsen; Donald L. Stevens; Anthony R. Selle; Steven G. Paulsen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 1 - 11 | Environmental Monitoring and Assessment Program, EMAP-Surface Waters: A Northeast Lakes Pilot | In response to a growing need for statistically sound information on status and trends in the condition of the nation's ecosystems, the U.S. Environmental Protection Agency is developing and implementing the Environmental Monitoring and Assessment Program (EMAP). One component, EMAP-Surface Waters, will concentrate on lakes and streams. In its focus on lake condition at the regional and national scale, EMAP-Surface Waters will address concerns about the present extent and geographical distribution of lakes, their current ecological condition, the proportion that is degrading or improving, where, and at what rate, and the likely causes of adverse effects. The national design is based on a systematic grid of randomly placed points, so that conditions and trends can be estimated with known uncertainty. Lake condition will be assessed primarily through biological measurements; physical, chemical, and landscape information will be used to support and interpret conditions estimated by the biological indicators. In late summer of 1991, EMAP-Surface Waters will conduct a pilot lake assessment in the northeastern United States. This paper describes the EMAP design and indicators strategy tailored for lakes, with examples showing how these indicators can describe condition and trends at national and regional scales. |
| Validation and Use of Ontario's Trophic Status Model for Establishing Lake Development Guidelines | Neil J. Hutchinson; B. P. Neary; P. J. Dillon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 13 - 23 | Validation and Use of Ontario's Trophic Status Model for Establishing Lake Development Guidelines | The Trophic Status Model of Ontario's Lakeshore Capacity Study is a refinement of the Dillon-Rigler (1975) model for predicting total phosphorus concentration and several trophic status indicators in lakes. A recent version of this model allows the modeling of watersheds, extending 3 lakes upstream for up to 15 catchments of a study lake. This feature enables lake managers to predict the effect of lakeshore development throughout an entire watershed, including downstream lakes. Differences between modeled and measured concentrations of total phosphorus for the ice-free period were less than 20% in 11 of a set of 15 lakes in a south-central Ontario watershed. Annual, seasonal and long-term coefficients of variation for measured phosphorus concentrations were 19-22% over a 9-year period in an intensively studied lake. Assumptions and sources of error in modeled and measured phosphorus concentrations are discussed. The ability of the Trophic Status Model to predict phosphorus concentrations in the absence of development is discussed and used to establish water quality objectives for total phosphorus on an individual lake basis. |
| Sediment Phosphorus Loading Beneath Dense Canopies of Aquatic Macrophytes | Jonathan D. Frodge; G. L. Thomas; G. B. Pauley | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 61 - 71 | Sediment Phosphorus Loading Beneath Dense Canopies of Aquatic Macrophytes | Dense surface canopies of aquatic macrophytes were associated with significant changes in the physical and chemical water quality of two shallow Pacific Northwest lakes. Internal loading of phosphorus (P) was observed at the sediment-water interface beneath canopies of Ceratophyllum demersum L. and Myriophtllum exalbescens (Fern.) Jeps. and in deep open-water areas when dissolved oxygen (DO) concentrations were ≤0.4 mg/L. Aerobic release of P was observed at sites with surface covers of the green filamentous algae Pithophora sp. where concentrations of DO were >20 mg/L and pH >9. An increase in surface P concentrations was also observed in sites dominated by the floating leafed Brasenia schreberi Gmel., and appeared to be associated with leaf decay within the surface canopy. There was an apparent net loss of phosphorus to the sediments beneath both submergent and floating leafed canopies when DO concentrations were ≥0.4 mg/L. The removal or reduction of the plant canopies could simultaneously reduce anoxic P release, while increasing aerobic P release. These P cycling mechanisms should be considered in the management of aquatic macrophytes. |
| Computer Mapping for Monitoring and Assessment of Surface Water Reservoirs | Herbert J. Grimshaw; William L. Cauthron; Frank R. Schiebe; Sherwood C. McIntyre | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 73 - 87 | Computer Mapping for Monitoring and Assessment of Surface Water Reservoirs | A flow-through, water quality monitoring system, designed to evaluate the spatial heterogeneity of water quality in reservoirs (Grimshaw, 1987), was used to sample Lake Thunderbird, a reservoir near Norman, Oklahoma. Field testing was conducted to evaluate the operational feasibility of monitoring several water quality parameters along multiple transects, in a real-time manner. Results were processed and interpolated using two computer mapping systems and synoptic maps were generated. Qualitative and quantitative comparisons of the two mapping techniques were made. A synoptic map of turbidity, generated from Landsat Multispectral Scanner Band 3 (700-800 nm) data was compared to results obtained from both computer mapping techniques. With the exception of pH and turbidity, the synoptic maps provided similar estimates of lake area within selected intervals, but differed in the degree of detail revealed. Landsat-based turbidity estimates were higher than those measured directly in the littoral zone. |
| Grazing Effects of an Exotic Bivalve (Corbicula fluminea) on Hypereutrophic Lake Water | John R. Beaver; Thomas L. Crisman; Robert J. Brock | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 45 - 51 | Grazing Effects of an Exotic Bivalve (Corbicula fluminea) on Hypereutrophic Lake Water | This preliminary study evaluates the ability of the widespread, exotic clam Corbicula fluminea to influence the characteristics of plankton in eutrophic Florida lakes. Effective clam densities of 1310 m-2 and 2621 m-2 reduced chlorophyll a concentrations in hypereutrophic lake water > 60 per cent over 7 days. Clam filtration rates were estimated to be approximately 500 ml hr-1 clam-1. Zooplankton communities shifted to dominance by copepods in all treatments, although rotifer populations declined more rapidly in clam treatments. Although clams stimulated dissolved nitrogen concentrations, phytoplankton populations were reduced. Potential effects of Corbicula fluminea on plankton characteristics of subtropical lakes are discussed. |
| Newnans Lake, Florida: Removal of Particulate Organic Matter and Nutrients Using a Short-term Partial Drawdown | Johan F. Gottgens; Thomas L. Crisman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 7 | 1 | 1991 | 53 - 60 | Newnans Lake, Florida: Removal of Particulate Organic Matter and Nutrients Using a Short-term Partial Drawdown | Spillways at lake outlets are commonly employed to reduce water level fluctuations and promote year-round lake access. However, stabilized water levels may cause accelerated accumulation of sediment on the lake bottom. This can change aquatic plant communities, cloud the water, and eliminate hard-bottom nesting areas for many sportfish. These effects may be particularly pronounced when spillway design does not allow for bottom water drainage and outflow is restricted to less turbid surface waters. Such a structure controls the single surface-outflow of shallow, algal-dominated Newnans Lake, Florida. A 90-day removal of this spillway flushed 60 metric tons (dry weight) of sediment (containing 15% total Kjeldahl nitrogen and 0.5% total phosphorus) from the lake. This quantity was small compared to the likely stores in the lake, but the removal was accomplished at no cost. Data suggest low lake stage at the start of dewatering, resulting in small hydraulic head and low flow through the lake system depressed removal rates. Elevated concentrations of particulate organic matter (POM), total Kjeldahl nitrogen (TKN), and total phosphorus (TP) were noted during the first month of dewatering when adequate head differential was still present. Storms stirred the water column and promoted flushing of resuspended matter. In situ and laboratory tests did not demonstrate net oxidative removal of organic matter from exposed areas of the lake bottom. Production of organic matter under high solar radiation and nutrient availability likely replaced material lost through oxidation. Consolidated sediments remained firm after reflooding, providing improved habitat for rooted macrophytes and fish spawning. Short-term partial drawdowns are inexpensive and effective in flushing organic matter and nutrients when they are initiated at high lake stage and coincide with frequent storm events. Routine application of this management technique may produce a periodic rejuvenation of the lake ecosystem. |
| Loading Model Predictions of Total Phosphorus in an Offset Reservoir | Dale W. Toetz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 181 - 186 | Loading Model Predictions of Total Phosphorus in an Offset Reservoir | Offset reservoirs deserve study because of their importance in water supply systems, yet little information is available about how these lakes process nutrients. To close this gap the water, nitrogen and phosphorus budgets were determined for an offset reservoir, Lake Hefner, Oklahoma. During 1981, about 87 percent of the water and 88 percent and 97 percent of the nitrogen and phosphorus entered the lake via a canal connecting the North Canadian River to the lake. The lake accumulated both nitrogen and phosphorus. The sedimentation coefficient (R) for phosphorus was 0.86 yr-1. Loading models developed for artificial lakes predicted roughly the same total phosphorus concentrations as were observed in the lake, although not precisely. Apparently, offset reservoirs are not special cases of artificial lakes. These conclusions were based upon a data set for only one year and do not reflect year-to-year variability. An empirical monitoring approach is suggested for management of offset reservoirs. |
| Effects of Triploid Grass Carp on Aquatic Vegetation in Two South Dakota Lakes | Daryl L. Bauer; David W. Willis | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 175 - 180 | Effects of Triploid Grass Carp on Aquatic Vegetation in Two South Dakota Lakes | Triploid grass carp (Ctenopharyngodon idella) were stocked at a mean length of 229 mm (total length) into two small South Dakota lakes in 1985. Chara sp. was the predominant aquatic macrophyte in both lakes. Prior Lake contained a fish community in which the largemouth bass (Micropterus salmoides) was the only top-level predator. An introduction of 49 grass carp per hectare resulted in nearly complete elimination of vegetation within two years. Northern pike (Esox lucius) was the dominant predator in East Lake Eureka. Grass carp were introduced at a density of 61 per hectare, but no impact on aquatic vegetation was noted. We believe northern pike predation reduced grass carp numbers. Therefore, we suggest that further work is needed on size of grass carp stocked in waters containing northern pike. |
| Estimating Intermittent Runoff Concentrations of Organic Matter and the Allochthonous Organic Loading of New Mexico Reservoirs | Richard A. Cole; Timothy J. Ward; Susan M. Bolton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 187 - 196 | Estimating Intermittent Runoff Concentrations of Organic Matter and the Allochthonous Organic Loading of New Mexico Reservoirs | Variations in the concentrations of total and particulate organic matter were estimated from 1979 through 1988 in natural and simulated runoff events to improve estimates of reservoir gross organic loading from intermittent flows. Total organic matter concentrations in natural runoff from pinyon-juniper watersheds and particulate organic matter concentrations in runoff from creosote bush watersheds increased as a natural logarithmic function of discharge. Total organic matter and particulate organic matter discharge-weighted concentrations in natural runoff events were related to measurements of instantaneous discharge and total organic matter and particulate organic matter concentrations, and to estimates of the maximum discharge of total organic matter and particulate organic matter concentrations that occurred in the event. In rainfall simulations conducted in watersheds of creosote bush, desert grass, pinyon-juniper, ponderosa pine, and spruce meadow, only particulate organic matter concentrations in ponderosa pine differed significantly (P ≤ 0.05) from the other sites; there, concentrations were lower. The percentage of organic matter in the total suspended solids eroded during simulated runoff events decreased as vegetation cover decreased and bare soil area increased. Estimates of gross annual total organic matter loading revealed large annual variations at specific reservoirs and large variations of mean annual loading among reservoirs. These results suggest that intermittent runoff has a significant potential impact on reservoir trophic states in arid and semi-arid regions. |
| Swedish Agricultural Nonpoint Source Pollution: A Summary of Research and Findings | Sven-Olof Ryding; Magnus Enell; Lena Wennberg | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 207 - 217 | Swedish Agricultural Nonpoint Source Pollution: A Summary of Research and Findings | During the last decade Swedish agriculture has modernized considerably, as evidenced by increasing crop yields and declines in the amount of arable land and number of farmers. Two results of this agricultural modernization have been declining air and water quality. This paper summarizes what Swedish researchers have learned from long-term measurements of nutrient losses from agriculture and the subsequent effects on the surrounding environment. The results presented here are a collection of important findings from many Swedish research teams, including some work carried out by the authors. The conclusions can be summarized briefly as follows: Swedish agriculture contributes about one-third of the total nitrogen emissions to air through evaporation of ammonia from the handling of manure, with subsequent effects on vegetation and acidification of soils and waters. More than half of the ammonia deposited in Sweden originates from other northern European countries. A complex pattern, including background and human factors, influences the leaching of nitrogen and phosphorus to water. Leaching has increased since the 1950s, although atmospheric conditions also play an important role. Agricultural activities are only one reason for the pollution of coastal waters and the open sea surrounding Sweden. Other sources of significant pollution are atmospheric deposits, forestry, households, and urban stormwater. International understanding of the environmental problems caused by agriculture is urgently needed to ensure successful management of eutrophication. About 9 percent of the total nitrogen load and 5 percent of the total phosphorus load on the surrounding seas originate from Sweden. There are many ways to reduce the pollution caused by agriculture. The cost-effective options include tailoring fertilizer application to soil content and crop requirements, redistributing excess manure to manure-deficient farms in other areas, and introducing “wintergreen†plants. Before pollution from agriculture can be controlled, pollution must be understood. Without that understanding, efforts to prevent pollution may be neither helpful nor cost effective. |
| Evaluating the Restoration Potential of 19 Ohio Reservoirs | Donald G. Fulmer; G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 197 - 206 | Evaluating the Restoration Potential of 19 Ohio Reservoirs | Eighty-four percent of Ohio's lakes and reservoirs are eutrophic. Significant reductions in nutrient loading are usually the object of lake restoration projects. However, variations in attainable nutrient concentrations, based on regional differences in watershed characteristics and land use, often are not considered. The purpose of this project was to evaluate the “ecoregion†concept for estimating which surveyed Ohio reservoirs might have the greatest potential for reduction in phosphorus concentrations. Ecoregional watershed characteristics dictate the practical lower or attainable limits of stream nutrient concentrations that can be reached. Attainable reservoir phosphorus concentrations were estimated from stream phosphorus concentration data that represent the best water quality in each Ohio ecoregion and by the use of a loading model. The reservoirs with actual summer 1989 phosphorus concentrations that exceeded predicted attainable concentrations by the greatest amounts were considered to have the greatest potential for restoration. These were not reservoirs with the worst trophic states. Similar findings have been reported for Minnesota (Heiskary et al. 1987). The method proposed here could be used statewide to establish water quality standards, provide a rational way to establish a priority program for lake restoration, and develop lake improvement and protection goals. |
| Limnological Factors Influencing Bird Abundance and Species Richness on Florida Lakes | Mark V. Hoyer; Daniel E. Canfield Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 133 - 141 | Limnological Factors Influencing Bird Abundance and Species Richness on Florida Lakes | Forty-six bird species were observed on 33 Florida lakes with some species occurring on only one lake and others on as many as 26 lakes. Average annual bird abundance ranged from seven to 750 bird/km2 and total species richness ranged from two to 30 species per lake. Regression analyses were used to examine the effects of lake trophic status, aquatic macrophyte abundance, and lake morphology on average annual bird abundance and total species richness. All trophic state parameters (total phosphorus, total chlorophyll a, etc.) accounted for significant portions of the variance in average annual bird abundance, but total chlorophyll a concentrations (μg/L) accounted for the highest percentage (47 percent) of the variance. The best fit regression equation was: Log Bird Abundance = 1.35 + 0.56 Log Total Chlorophyll a . Lake area, shoreline length, and all trophic state parameters accounted for significant portions of the variance in total species richness. Multiple regression analyses indicated that lake area (km2) and total chlorophyll a (μg/L accounted for the highest percentage (87 percent) of the variance in total species richness (species/lake). The best-fit multiple regression equation was: Log Species Richness = 1.10 + 0.47 Log Lake Area + 0.17 Log Total Chlorophyll a . After accounting for lake trophic status and lake area, neither aquatic macrophyte abundance nor lake morphology accounted for additional variances in average annual bird abundance or total species richness. |
| Effects of Nutrients and Non-algal Turbidity on Blue-green Algal Biomass in Four North Carolina Reservoirs | Val H. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 125 - 131 | Effects of Nutrients and Non-algal Turbidity on Blue-green Algal Biomass in Four North Carolina Reservoirs | An analysis of data from four turbid North Carolina reservoirs showed that both the summer mean biomass and relative biomass of planktonic blue-green algae (Cyanophyta/Cyanobacteria) are frequently lower than would be predicted by models developed from natural north temperate lakes. These results are consistent with the hypothesis that the growth of blue-green algae in these reservoirs is reduced in the presence of high concentrations of non-algal turbidity. |
| Occurrence and Prediction of Algal Blooms in Lake Taneycomo | Matthew F. Knowlton; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 143 - 152 | Occurrence and Prediction of Algal Blooms in Lake Taneycomo | In summer 1988, Lake Taneycomo, Missouri, developed conspicuous algal blooms as a result of low inflow from an upstream hydropower reservoir and phosphorus loading from a point source. In multiple regression models, variation in total phosphorus concentration and an index of water residence time accounted for 78-85 percent of the variation in transparency, chlorophyll, and volatile suspended solids in surface water. Non-equilibrium conditions in this rapidly flushed lake led to rapid and predictable increases in algal standing crops during lulls in power generation. |
| Jet Mixing in Lake or Reservoir Stratification Simulations | Ruochuan Gu; Heinz G. Stefan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 165 - 174 | Jet Mixing in Lake or Reservoir Stratification Simulations | MINLAKE, a dynamic, one-dimensional, unsteady lake water stratification simulation model has been extended by a water jet mixing submodel (JETMIX). The model is intended primarily to evaluate lake management and control strategies. The extended model simulates the continuous change of lake stratification in response to artificial mixing induced by water jets and natural mixing by wind and cooling. Artificially forced summer destratification with a recirculating pump/jet discharge system, and a warm water jet discharged into an ice-covered lake were studied. Numerical results were obtained to predict the effect of jet mixing on the evolution of water temperature and dissolved oxygen profiles in time. The effect of the warm water jet discharge on the ice cover was of particular interest. The simulation model was verified with laboratory experimental data. The capabilities and applicability of the model were illustrated with simulations of a hypothetical summer destratification and a planned winter discharge. The results can be used to design a hydraulic jet-mixing system for a lake or reservoir in summer and a submerged thermal outfall for year-round conditions. |
| Overcoming the Tragedy of the Commons: Alternative Lake Management Institutions at the Community Level | Robert M. Korth; Lowell L. Klessig | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 219 - 225 | Overcoming the Tragedy of the Commons: Alternative Lake Management Institutions at the Community Level | Public lakes are classic candidates for the “tragedy of the commonsâ€: use by everybody, management by no one. In a state with many such lakes, only the care and concern of local communities can overcome this syndrome. This paper summarizes the legal basis and functional role of the institutions involved with lake management in Wisconsin. Within that context, the activities and finances of sanitary districts, lake districts, and lake associations are compared. Among 36 activities, lake districts are most active in 26, lake associations are most active in 9, and sanitary districts are most active only in the provision of public sewers. Among all lake organizations, monitoring activities are most common, followed by newsletter publishing, fish management, support for local ordinances, and weed harvesting. Sanitary districts and lake districts are primarily funded through their taxing powers, while lake associations depend on dues and fundraisers. |
| Estimating Fluvial Mass Transport to Lakes and Reservoirs: Avoiding Spurious Self-correlations | David L. Galat | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 2 | 1990 | 153 - 163 | Estimating Fluvial Mass Transport to Lakes and Reservoirs: Avoiding Spurious Self-correlations | Three approaches to estimating fluvial mass transport to receiving waters are reviewed: concentration-discharge regressions, load-discharge regressions, and concentration discharge product methods. Concentration-discharge regressions are applied when constituent concentration (C) depends on river discharge. Several dilution, concentration and mixed-effects linear regression models are illustrated. The load (L)-discharge (Q) regression form: log L = a + b (log Q), where L = CQ, is widely used to estimate mass transport because it yields high coefficients of determination (R2) when concentration-discharge regressions do not. This is illustrated for Truckee River, Nevada, using eight years of monthly total nitrogen concentration ([TN]) and discharge data. However, the observed high R2 (0.92) results from product spurious self correlation, where the discharge term appears on both sides of the regression equation, and is not due to a dependency of [TN] on discharge. When concentrations do not depend on discharge, constituent loadings should be estimated as the product of concentration and discharge. Several concentration-discharge product methods are given for fixed-time-interval or flow-interval sampling of concentration. |
| The Importance of Flow Regimes in Assessing the Impact of Agricultural Runoff on Reservoir Water Quality and Zooplankton Abundance | John R. Shuman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 71 - 80 | The Importance of Flow Regimes in Assessing the Impact of Agricultural Runoff on Reservoir Water Quality and Zooplankton Abundance | The impact of silt and clay loading from an agricultural watershed on zooplankton abundance and several physical, chemical, and biological measures of water quality was assessed during stormflow and baseflow flow regimes in Tuttle Creek Reservoir, near Manhattan, Kansas. Bacteria and suspended solids increased during the stormflow period, while water transparency, chlorophyll a, dissolved solids, and zooplankton declined. The abundance and reproductive performance of Daphnia parvula and Daphnia pulex in predator-free enclosures incubated along the longitudinal axis of the reservoir also decreased significantly during the stormflow period. Chlorophyll a, suspended solids, and dissolved solids were spatially distributed during the sampling period with highest concentrations at the riverine end of the reservoir where water transparency was lowest. Diaphanosoma sp. and calanoid copepods exhibited high abundances at the riverine end of the reservoir while Daphnia sp., Bosmina sp., and cyclopoid copepods exhibited low abundances there. The reproductive performance of Daphnia parvula in enclosures, however, was significantly greater at the riverine end, where silts and clays are most abundant. These spatial and temporal patterns in water quality, zooplankton abundance, and Daphnia reproductive performance demonstrate the importance of flow regime and the magnitude of its associated suspended sediment load from agricultural runoff on reservoir water quality and zooplankton dynamics. |
| Modeling Phosphorus Loading to Three Indiana Reservoirs: A Geographic Information System Approach | Daniel A. Levine; William W. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 81 - 91 | Modeling Phosphorus Loading to Three Indiana Reservoirs: A Geographic Information System Approach | This paper describes a geographic information system (GIS) approach to modeling the effects of distance to water and slope angle on external phosphorus loading to lakes. A raster GIS database was created that included land use, topography, soils, and watershed boundaries for three Indiana reservoirs (Lakes Kickapoo, Lenape, and Shakamak). Three sets of phosphorus export coefficients were selected and assigned to each cell according to land use. Linear filters were designed and applied to the export coefficients such that areas nearest the water and with the steepest slopes would contribute the greatest amount of phosphorus relative to the initial phosphorus export coefficient. These filtered coefficients were used to calculate aerial phosphorus loading and in-lake phosphorus concentrations. The predicted concentrations were within 5 μg/L of the observed phosphorus concentration in Lake Shakamak for three modeling scenarios, and within 22 μg/L of the observed concentration in Lake Lenape for three scenarios. Predictions of phosphorus concentrations in Lake Kickapoo were consistently low (35 percent to 95 percent). This may have resulted from the complex hydrology of Lake Kickapoo or the inability to accurately model the physical processes as intended. The GIS system was useful for modeling the effects of distance and slope on phosphorus loading and for providing data highlighting critical management areas. |
| Interactions of Chironomidae and Chaoboridae (Diptera) with Aluminum Sulfate Treated Lake Sediments | Richard P. Narf | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 33 - 42 | Interactions of Chironomidae and Chaoboridae (Diptera) with Aluminum Sulfate Treated Lake Sediments | Mesotrophic and eutrophic lakes have been treated with aluminum salts (alum) to lower phosphorus concentrations and inhibit phosphorus recycling from the sediment. Changes in the profundal benthic and merobenthic fauna of five selected lakes were assessed, revealing increases in faunal density and diversity in nearly all treated lakes. The dominant organisms were Chaoborus punctipennis (Say) and Chironomus spp. Sediment cores used to evaluate the presence of an aluminum hydroxide floc layer showed aluminum concentrations above extrapolated background levels in most cores within the top 20 cm of substrate. Increased chironomid density resulting from such treatments might reduce the expected benefit from the alum addition. To assess the effect of sediment bioturbation, a bioassay with Chironomus tentans F. larvae was carried out to determine if translocation of phosphorus across the flocculent barrier is dependent on floc thickness or chironomid density. In the absence of a floc layer, chironomid activity generated higher concentrations of soluble reactive phosphorus (SRP) than when a floc layer was present. Even with a floc layer of 0.5-2.0 cm thickness, chironomids were able to increase soluble reactive phosphorus concentrations. Soluble reactive phosphorus concentrations in assays with alum and no insects were at or below the detectable limit of 4 μg/L. Alum toxicity to insects was not apparent in the lake treatment part of this assessment. An indirect toxicity was observed in the bioassays when alum dosages greater than 75 mg Al+3/L were used. The absence of toxicity in bioassays at lower treatment rates, which are more indicative of normal aluminum salt usage, indicates that this phosphorus reduction technique is relatively safe to Chironomus tentans . |
| Effects of Alum Treatment on Phosphorus and Phytoplankton Dynamics in Eau Galle Reservoir: A Synopsis | J. W. Barko; W. F. James; W. D. Taylor; D. G. McFarland | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 1 - 8 | Effects of Alum Treatment on Phosphorus and Phytoplankton Dynamics in Eau Galle Reservoir: A Synopsis | Eau Galle Reservoir, located in west central Wisconsin, is a small eutrophic flood control impoundment. The reservoir sustains high sediment and associated nutrient loadings from its agricultural watershed. Despite this system's riverine nature, much of the phosphorus accumulated in the water column during the summer derives typically from internal loading. Entrainment of phosphorus in the epilimnion from hypolimnetic sources during weather-induced partial mixing events has encouraged the development of large phytoplankton blooms. In 1986 internal phosphorus loading was substantially reduced by applying alum to profundal sediments. However, this effect was short-lived (< 1 year) because of high rates of sedimentation with probable burial of alum. Phytoplankton production was not diminished by alum treatment, partly because of high rates of external phosphorus loading during the unusually wet summer of 1986. In addition to inputs from the anaerobic hypolimnion, phosphorus is also transported to surface waters from the littoral zone by convective exchange flows driven by diel changes in water temperature. Phosphorus release from littoral sediments is enhanced at elevated values of pH, induced by macrophyte and phytoplankton photosynthesis. Groundwater discharge may provide another source of phosphorus to the epilimnion of Eau Galle Reservoir. Ceratium hirundinella and other dominant phytoplankton species (blue-green algae) possess significant vertical migrational capabilities, and are thus able to maximize phosphorus uptake whether from the hypolimnion, the littoral zone, or directly from riverine inputs. As with many other eutrophic reservoirs, it is difficult to control nutrient inputs from external sources in Eau Galle Reservoir. Control of internal sources of phosphorus loading to this reservoir appears to be equally difficult. |
| A Successful Alum/Aluminate Treatment of Lake Morey, Vermont | Eric Smeltzer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 9 - 19 | A Successful Alum/Aluminate Treatment of Lake Morey, Vermont | Lake Morey, Vermont provides a case history of a successful lake restoration effort. Decades of algal blooms and a major summer fish kill preceded a hypolimnetic alum and sodium aluminate treatment in 1986. Earlier diagnostic studies with paleolimnological analyses and a detailed phosphorus budget revealed the cause to be internal phosphorus loading from anoxic hypolimnetic sediments. The aluminum treatment of these sediments resulted in sharp declines in total phosphorus and chlorophyll a concentrations, and increased Secchi transparency. The dose rate of 44 g Al/m2 appears to have been sufficient to form an effective barrier to sediment phosphorus release, and improved conditions continue to persist after four years. Elevated dissolved aluminum levels and some possible adverse effects on the benthic invertebrates and the yellow perch population were temporarily observed following the treatment. The apparent success of the project in controlling phosphorus concentrations is the result of an accurate diagnosis of sediment release as the dominant source of phosphorus and the appropriate use of aluminum treatment to inhibit release. |
| Factors Affecting the Sport Fishery in a Multiple-use Virginia Reservoir | John J. Ney; Christopher M. Moore; Mark S. Tisa; Jeffrey J. Yurk; Richard J. Neves | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 21 - 32 | Factors Affecting the Sport Fishery in a Multiple-use Virginia Reservoir | Smith Mountain Lake, an 8,300 ha hydroelectric impoundment in south-central Virginia, experienced a sharp decline in its sport fishery beginning in the late 1970s. Potential causes were investigated over a three-year period and included: (1) increased hydroelectric pumpback operations; (2) reduced nutrient loading; and (3) trophic interactions between native and introduced fishes. Expanded hydroelectric operations did not substantially affect littoral and pelagic fish habitat. However, fish standing stock was highly correlated with total phosphorus concentration; both declined by over 75 percent between 1975 and 1984. Predation and competition of introduced and native fishes were minimized by habitat segregation, but forage fish production was inadequate to sustain a high abundance of piscivorous sport fishes. Restorative measures should focus on reduced piscivore stocking, increased harvest of juvenile sport fish, habitat enhancement, and adjustment of angler expectations to match the limits on fishery productivity imposed by other uses of the reservoir. This case study illustrates the need for effective planning in the management of reservoir fisheries, including consideration of issues at the design stage, frequent assessment, establishment of a protocol for introduction, new species, and compromise among users with different goals. |
| The Management of Lake Chapala (México): Considerations After Significant Changes in the Water Regime | J. Gualberto Limón MacÃas; Owen T. Lind | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 61 - 70 | The Management of Lake Chapala (Mxico): Considerations After Significant Changes in the Water Regime | Forty-five percent of the water from the river supplying Lake Chapala has been diverted in the past 10 years. The water quality consequences of this change in water quantity are numerous. In this period, the lake volume has declined by 50 percent. Because of the reduced flushing and the corresponding relative increase in outputs via evaporation more than twofold, the lake's total dissolved solids content has increased. A second consequence, and one of great importance to the ecology of the lake, is the increase in water turbidity. With a reduction in lake mean depth from 7.2 m to 4.5 m, wind-driven resuspension of the inorganic sediments has increased. This has caused light limitation of phytoplankton production to the extent that nutrient loading models to predict production of biomass fail when applied to this lake. Reduction in turbidity by increased flocculation could significantly speed up the eutrophication process, because high concentrations of nutrients are present in the system (total inorganic phosphorus = 520 μg/L and total inorganic nitrogen = 512 μg/L). Because of the importance of this lake as a water supply resource and the unique nature of the water quality problems, a special set of water quality criteria appropriate to Lake Chapala is presented. To avoid further reduction in the water supplied to Lake Chapala from the River Lerma, its principal influent, consumptive water use in the River Lerma cannot increase. Further increases in the irrigated areas should come only from other water sources (e.g., wastewater reuse) or more efficent irrigation. |
| Monitoring Design and Data Analysis for Trend Detection | Kenneth Reckhow; Craig Stow | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 49 - 60 | Monitoring Design and Data Analysis for Trend Detection | This study was undertaken to assess the effectiveness of alternative water quality monitoring programs in detecting water quality trends over time, identifying differences in water quality between water bodies, and examining spatial variability in water quality within a single water body. Monthly historical data on phosphorus, nitrogen, and specific conductance from the North Carolina Division of Environmental Management and the U.S. Army Corps of Engineers were analyzed. The historical data on nutrients and specific conductance were first examined for deterministic patterns. In most cases, the concentration varied seasonally according to a cyclical pattern that repeated each year. In addition, concentration at riverine sampling sites was often inversely related to streamflow. Following removal of the deterministic patterns from the data, autocorrelation was found in a few cases. Once it was concluded that only white noise remained in residuals for a particular data series, the required sample size for a given power and significance was calculated. In many instances, a large number of samples were required to detect changes of 25 percent or less with low error rates, because of the high level of background variability. |
| Internal Phosphorus Loading and Macrophytes: an Alternative Hypothesis | Eugene B. Welch; T. Scott Kelly | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 43 - 48 | Internal Phosphorus Loading and Macrophytes: an Alternative Hypothesis | Rooted, submersed macrophytes, primarily Elodea densa, have apparently served to restrict internal phosphorus loading during the summer in shallow Long Lake, Washington, instead of contributing phosphorus through senescence (process of aging). Internal loading was consistently controlled for five years by treatment by drawdown and alum, and mean, whole-lake macrophyte biomass ranged from about 30 to 250 g/m2 during the 12 study years. Instead of the positive relationship between macrophyte biomass and lake phosphorus content during the summer that has been observed by others, the two variables had an inverse relationship. Gross internal loading (before and after alum control), estimated by a nonsteady-state model, was greater during years when low winds (< 10 km/h) were frequently followed by high winds (> 16 km/h). This indicates the importance of stability in creating an anoxic layer over the sediment, followed by wind mixing to entrain it into the water column. Thus, rather than serving as a direct source in summer through senescence, a dense cover of macrophytes in this lake may impede sediment release of phosphorus by creating a barrier to wind mixing. Late fall and winter senescence may, however, facilitate sediment phosphorus release by the iron-redox mechanism through organic enrichment of the sediment surface. The varied role of macrophytes since treatment suggests that partial alum control may have persisted for at least nine years. |
| Evaluation of Calcium Carbonate and Calcium Hydroxide Treatments of Prairie Drinking Water Dugouts | T. P. Murphy; E. E. Prepas; J. T. Lim; J. M. Crosby; D. T. Walty | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 101 - 108 | Evaluation of Calcium Carbonate and Calcium Hydroxide Treatments of Prairie Drinking Water Dugouts | In 1987, lime (250 mg/L calcium carbonate or 250 mg/L calcium hydroxide) was added to four hardwater dugouts in northwestern Alberta to precipitate the phosphorus and algae and improve water quality. Calcium carbonate reduced algal biomass to 39 percent of pretreatment concentrations between June and August of 1987, but dugouts recovered to pretreatment concentrations during the next summer. Calcium hydroxide treatments reduced algal biomass to 12 percent of pretreatment concentrations and dugouts remained at that level over the following summer. Phosphorus concentrations were decreased by 80 percent in calcium hydroxide-treated dugouts but were relatively constant in calcium carbonate-treated dugouts. Calcium hydroxide treatments can improve water quality in dugouts for a chemical cost of $200-$400. |
| Analysis and Applications of Lake User Survey Data | Eric Smeltzer; Steven A. Heiskary | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 109 - 118 | Analysis and Applications of Lake User Survey Data | Lake management often requires assessment of water quality impacts on lake users. Lake user surveys provide a means for linking sampling parameters such as total phosphorus, chlorophyll a, or transparency and user impacts such as nuisance algae levels and recreational impairment. A lake user survey was conducted on nearly 500 lakes in Minnesota and Vermont concurrently with citizens' water quality sampling programs. The results showed that quantifiable and statistically significant relationships existed between eutrophication-related water quality measurements and user perceptions of nuisance algal conditions. However, strong differences existed in these relationships between the two states and among lake regions within each state, indicating that specific regional relationships should be developed whenever possible. This report describes applications of lake user survey results, including statewide lake assessments, wastewater discharge impact evaluations, lake management goal setting, and water quality standards development. |
| Wind-related Limnological Variation in Lake Okeechobee, Florida | Michael J. Maceina; David M. Soballe | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 6 | 1 | 1990 | 93 - 100 | Wind-related Limnological Variation in Lake Okeechobee, Florida | Lake Okeechobee, Florida, is large (1730 km2) and shallow (Zx = 2.7 m) with 44 percent of the bottom covered by flocculent, unconsolidated mud. Consequently, wind resuspension of sediments was an important determinant of limnological conditions between 1975 and 1988. Higher wind speeds occurred between October and May, and calmer conditions were prevalent during the summer months (June-September). Monthly averages of soluble reactive phosphorus, total phosphorus, nitrate-nitrite, total nitrogen, silica, total suspended solids concentrations, and turbidity were positively correlated with average monthly wind speed (r = 0.66 to 0.90, P <0.05). Annual total wind speed was correlated with average annual total phosphorus (r = 0.78, P <0.01) and soluble reactive phosphorus (r = 0.67, P <0.05) concentrations. From 1950 to present, greater wind speed was also associated with higher lake stages. Wind speed, rainfall on the lake, tributary inflow, and lake levels appeared to be interrelated parameters on Lake Okeechobee. |
| Perlphyton as Indicators of Enrichment in Lake Pend Oreille, Idaho | Jacob Kann; C. Michael Falter | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 39 - 48 | Perlphyton as Indicators of Enrichment in Lake Pend Oreille, Idaho | Periphyton in the littoral zone of Pend Oreille Lake, a large (383 km2, deep (Zmax — 380 m)) meso-oligotrophic lake in northern Idaho, were studied to compare with pelagic productivity and to identify areas of inshore degraded water quality. Periphyton growth was determined on artificial tiles and natural substrates at 0.5 and 1.5 m depths. Means for all measures of production on natural substrates were higher than means for artificial substrate. Indicators of biomass were higher on 0.5 m tiles than those at 1.5 m; exposed sites, however, showed less difference between depths than did the more sheltered sites. Because of inorganic interference, ash-free dry weight provided a better measure of periphyton biomass than dry weight. Significant differences existed between sites, indicating greater algal growths in developed and relatively confined bays. Cymbellawas dominant on natural substrate, while Cymbella, Mougeotia, and Rhizocloniumwere co-dominant on artificial substrate. Blue-green algae biomass comprised only a small part of the total biomass on either artificial or natural substrates. Periphyton biomass in Pend Oreille Lake was comparable to other lakes showing accelerated eutrophication. Despite Pend Oreille Lake's great depth and large profundal area, littoral productivity was similar to lakes more shallow in nature with higher overall productivity. In-shore water quality degradation was documented at a time when open-lake conditions indicated the lake was meso-oligotrophic. Given that changes in lake trophic status would first show up in littoral areas-compared to the relatively slow changes taking place in the phytoplankton of pelagic areas-periphyton monitoring should provide valuable refinement to in-depth limnological studies on open waters of lakes. |
| Effects of Calcium Magnesium Acetate Deicer on Small Ponds in Interior Alaska | Jacqueline D. LaPerriere; Caryn L. Rea | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 49 - 57 | Effects of Calcium Magnesium Acetate Deicer on Small Ponds in Interior Alaska | Whole-lake experiments were conducted on three ponds in interior Alaska to test the effects of calcium magnesium acetate (CMA), an experimental road deicer, on aquatic organisms. The CMA added to the test ponds equalled approximately one chemical application applied to 0.4 km of a typical section of road (one lane) draining entirely to a small pond. Calcium elevation did not persist into the next summer; it may have been flushed out by snowmelt. Acetate from the CMA mixture was apparently rapidly taken up by aquatic organisms and cycled for several months, depleting dissolved oxygen in the water. Dissolved oxygen became extremely low in a small pond of about 2,600 m3 treated with 55 mg/L calcium acetate (calculated from calcium elevation). Bacteria and algae both appeared to be stimulated by CMA additions, as indicated by higher standing crops in treated ponds. The algae were probably stimulated by bacterial metabolism products of the acetate, or by phosphorus in the CMA used. Cladocerans were more dense in treated ponds than in control ponds, probably because more food (bacteria and algae) was available. Salmonid fishes, not present in the test ponds, might be stressed by low dissolved oxygen caused by CMA. |
| Properties of Selected Oklahoma Lakes in Relation to Remote Sensing of Suspended Sediment | R. G. Menzel; W. W. Troeger; F. R. Schiebe | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 31 - 37 | Properties of Selected Oklahoma Lakes in Relation to Remote Sensing of Suspended Sediment | Suspended solids and algal populations were characterized in 16 south central Oklahoma lakes to relate their properties to the spectral reflectances recorded by satellites. The average concentrations of natural suspended solids in the lakes ranged from 7 to 190 g/m3. Ash content increased from about 65 to 90 percent as suspended solids concentrations increased. Mean particle diameter, determined by photon correlation spectroscopy on samples with more than 40 g/m3 of suspended solids, ranged from 400 to 2,000 nm. Nutrient concentrations were low; dissolved inorganic nitrogen was less than 0.4 g/m3, and water-soluble phosphorus was less than 25 mg/m3. Algal populations were also low, with chlorophyll aconcentrations averaging 6 mg/m3 and rarely exceeding 20 mg/m3. Reflectances in the satellite spectral bands varied only slightly in response to changes in visual color and particle size of suspended solids in the turbid lakes. The relatively low chlorophyll concentrations could not be detected in the satellite spectral bands. |
| Review of Lake Management in Minnesota | Lawrence A. Baker; Edward B. Swain | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 1 - 10 | Review of Lake Management in Minnesota | Lake management practices in Minnesota have included holistic Clean Lakes Projects, extensive remedial methods to control excessive phytoplankton and macrophyte growth, and fisheries improvement projects. Clean Lakes projects have had varying degrees of success, but there has been no systematic evaluation of the overall success of the program. Remedial methods and fisheries management have narrow objectives, and the broader water quality impacts of these management practices have generally not been considered. Future lake management activities in Minnesota include developing better predictive and assessment capabilities, using innovative management techniques such as biomanipulation and community management of macrophytes, and renewing emphasis on controlling nonpoint source inputs to lakes. |
| Development of Lake Assessment Methods Based Upon the Aquatic Ecoregion Concept | C. Bruce Wilson; William W. Walker Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 11 - 22 | Development of Lake Assessment Methods Based Upon the Aquatic Ecoregion Concept | The development of practical lake management strategies in Minnesota has been greatly facilitated by using the aquatic ecoregion approach and standard assessment methodologies (models). Previous studies have shown the significance of the aquatic ecoregion in determining lake water quality patterns, water quality attainability, and development of nutrient criteria (Heiskary et al. 1987; Heiskary and Walker, 1988). This paper focuses upon the use of ecoregion data for modeling purposes. The Minnesota Lake Eutrophication Analysis Procedure (MINLEAP) is a computer program designed to predict eutrophication indices in Minnesota lakes based upon area watershed, depth, and ecoregion. Ecoregion is used to predict runoff and average stream phosphorus concentration. The program formulates water and phosphorus balances and uses a network of empirical models to predict lake phosphorus, chlorophyll a, and transparency values. The program is intended primarily as a screening tool for estimating lake conditions with minimal input data and for identifying “problem†lakes. Included in the program output are: (1) statistical comparisons of observed and predicted phosphorus, chlorophyll a, and transparency values; (2) uncertainty estimates; and (3) estimates of chlorophyll a interval frequencies (nuisance frequencies), for observed and predicted conditions. These expressionsof lake condition may be calibrated to citizen preferences using observer surveys (Heiskary and Walker, 1988) to define swimmable and nonswimmable conditions in a locally meaningful manner. The model should be used to approximate lake water quality expectations acknowledging that individual lakes may deviate greatly from regionally defined patterns. |
| Water Quality Monitoring in Spanish Reservoirs By Satellite Remote Sensing | Jose L. Ortiz-Casas; Ramon Peña-Martinez | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 23 - 29 | Water Quality Monitoring in Spanish Reservoirs By Satellite Remote Sensing | A United States-Spanish Cooperative Program is currently being performed between the U.S. Bureau of Reclamation and the Spanish Centro de Estudios y Experimentacion de Obras Publicas applying Landsat satellite digital imagery to eutrophication-related water quality monitoring in Spanish reservoirs. Landsat digital images provided by the thematic mapper sensors were processed with concurrent surface sampling data, to develop regression equations and water surface maps. Limnological parameters selected for the study were related to trophic conditions such as chlorophyll concentrations and Secchi transparency. While thematic mapping based on single-date regression equations has already proved feasible and reliable, more sophisticated processing is needed to develop equations for multiple-date assessment, that is, to enable assessment on any date remote sensing data are available whether concurrent water surface measurements are available or not. The long-term goal of this project is developing updated, cost-effective reservoir surveillance and classification on a regional or nationwide basis. |
| Phosphorus-Fish Community Biomass Relationships in Southern Appalachian Reservoirs: Can Lakes be too Clean for Fish? | Jeffrey J. Yurk; John J. Ney | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 83 - 90 | Phosphorus-Fish Community Biomass Relationships in Southern Appalachian Reservoirs: Can Lakes be too Clean for Fish? | Phosphorus is often the principal nutrient limiting primary production in the United States southeastern reservoirs, but its impact on higher trophic levels has not been assessed. A regression analysis was used in this study to examine the relationship between phosphorus concentration and fishes biomass over time in a Virginia reservoir and also in a set of 22 southern Appalachian reservoirs. Both phosphorus and fish biomass concurrently were measured. In the Virginia reservoir, which had experienced a nutrient reduction program, total phosphorus concentration and fish biomass declined together over an 11-year period. Phosphorus concentrations explained two-thirds of the annual variation in fish standing stock. Phosphorus was also the best fish biomass predictor for the southern Appalachian reservoir set, accounting for 75 percent of the variation in standing stock despite great diversity in size, morphometry, chemistry, species composition, and hydrology among impoundments. Predictive power was generally higher for forage fishes than for piscivores-attributed in part to human manipulation, specifically stocking and harvesting, of these sportfish species as well as to a trophic bottleneck in forage-fish availability. The strength and robustness of the regression relationships indicate that, for these systems, reducing phosphorus loading will cause a decline in the fishery. Nutrient abatement programs should be planned with full consideration of the potential trade-off between cleaner water and poorer fishing success. |
| Empirical Prediction of Zooplankton Biomass in Adirondack Lakes | Clifford A. Siegfried; James W. Sutherland | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 91 - 97 | Empirical Prediction of Zooplankton Biomass in Adirondack Lakes | Empirical models of zooplankton biomass (rotifer, crustacean, and rotifer + crustacean biomass) in relation to selected morphometric (depth, surface area, flushing rate, and watershed area) and chemical variables were developed for 20 Adirondack lakes. The chemical variables were selected to characterize acidity status (pH, acid neutralizing capacity, and aluminum concentrations), trophic status (total phosphorus, chlorophyll a, phytoplankton biovolume, and Secchi depth), and humic influences (with dissolved organic carbon and color serving as surrogates of humic materials). Additional independent variables included major cations and anions (Ca++, Mg++, Na+, K+, Cl-, and SO4-), specific conductance, dissolved oxygen, and temperature. Zooplankton biomass averaged 85.2 mg/m3 in the study lakes. Crustacean biomass accounted for an average of 65.9 mg/m3 and rotifer biomass for 19.4 mg/m3. Rotifer biomass was a significant component of zooplankton biomass in many circumneutral as well as acidic Adirondack lakes. The relative importance of rotifer biomass-as a percentage of total zooplankton biomass-could be predicted from an empirical relationship including the log of chlorophyll a, the log of monomeric aluminum, and true color as independent variables (R2 = .70). Rotifer biomass was particularly important in acidic lakes largely as a result of crustacean zooplankton loss rather than enhanced rotifer biomass. The best fit rotifer biomass empirical model included the log of total phosphorus and maximum depth as predictor variables (R2 = .69). Crustacean biomass was best described by a relationship that included the log of monomeric aluminum, the log of chlorophyll a, and the log of dissolved organic carbon (R2 = .70). The best fit empirical model for total zooplankton biomass was a combination of the above models including all the above independent variables except total phosphorus. This model, reflecting the interactions of acidity and productivity status and humic influences, accounted for 74 percent of the lake to lake variability in mean zooplankton biomass. |
| Evaluation of Phytoplankton–Limiting Factors in Lake Chapala, México: Turbidity and the Spatial and Temporal Variation in Algal Assay Response | Laura Dávalos; Owen T. Lind; Robert D. Doyle | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 99 - 104 | Evaluation of Phytoplankton-Limiting Factors in Lake Chapala, Mxico: Turbidity and the Spatial and Temporal Variation in Algal Assay Response | Laboratory algal bioassays using both cultures of Ankistrodesmus bibraianusand natural phytoplankton, and large, in-lake, container assays with natural populations, were used to determine the factor most limiting phytoplankton production in Lake Chapala, Mxico. Both types of laboratory culture assays showed that nitrogen was the principal limiting nutrient at each station across this very large lake in all seasons. The growth response of natural phytoplankton was similar to that of A. bibraianus. However, management practices to regulate the lake's productivity based solely upon this laboratory information would be inappropriate because the natural population assays showed that the ultimate limiting factor insituis illumination controlled by the high clay turbidity. Rarely, if ever, was phytoplankton production controlled by the laboratory-determined limiting nutrient, nitrogen, expressed in the lake. The importance of performing algal assays extensively through time and space also was demonstrated. The nitrogen-augmented increase over controls in A. bibraianusbiomass ranged from less than 50 percent at the end of the dry season to greater than 1,000 percent in the middle of the rainy season. The average annual percent response at different sampling stations ranged from 438 percent to 541 percent. Also, the sample to sample variation was different for different stations. The variation coefficient was only 35 percent for the mid-lake station, but greater than 84 percent for the station nearer the source of river inputs. |
| Preliminary Observations on Nutrient Enrichment of Semi-arid, Manmade Lakes in the Northern and Southern Hemispheres | J. A. Thornton; W. Rast | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 59 - 66 | Preliminary Observations on Nutrient Enrichment of Semi-arid, Manmade Lakes in the Northern and Southern Hemispheres | This paper is part of a multi-step assessment of the hypothesis that subtropical, semi-arid impoundments may respond differently to increasing nutrient enrichment than similar northern temperate waterbodies (primarily natural lakes) from which the classical lake eutrophication concept has been derived. Common physicochemical indicators of eutrophication are referenced, including nutrient status, phytoplankton biomass (chlorophyll), and hypolimnetic deoxygenation. Data from 89 reservoirs in the southwestern United States and southern Africa were used to examine the eutrophication-related limnology of these lakes. In particular, the effects of a large catchment area:lake surface area ratio (AD:A) on the turbidity, nutrient status, and phytoplankton standing crop were highlighted as distinct features relevant to semi-arid lake classification. The responses of reservoirs in semi-arid regions of the northern and southern hemispheres to nutrient enrichment are contrasted with responses of temperate lakes to highlight their implications for accurately assessing eutrophication of manmade lakes in subtropical, semi-arid areas. |
| The Selection of Appropriate Flow Averaging Periods in Evaluating Pollutant Loadings Using the Flow Interval Method | William P. Stack; Kenneth T. Belt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 67 - 73 | The Selection of Appropriate Flow Averaging Periods in Evaluating Pollutant Loadings Using the Flow Interval Method | Measurement of pollutant loadings is important in any lake management program. The flow interval method is among the most widely used today for this purpose. However, the Baltimore City Water Quality Management Office found this methodology to be extremely sensitive to the unit of flow (e.g. daily average, 15 minute discrete records) used in the computation. In three tributaries monitored, errors attributable to the flow unit used in phosphorus and sediment loading computations were found to be as high as 44 percent and 71 percent, respectively. Potential errors are greatest for streams with flashy hydrographs and a strongly positive flow/concentration relationship. The degree to which phosphorus and sediment loads are underestimated by using daily averaged flows varies with watershed, hydrologic year, and flow-concentration dynamics. |
| Phosphorus Dynamics in Agricultural Runoff and Reservoirs in Oklahoma | A. N. Sharpley; S. J. Smith; R. G. Menzel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 2 | 1989 | 75 - 81 | Phosphorus Dynamics in Agricultural Runoff and Reservoirs in Oklahoma | Concentrations of soluble and total phosphorus in runoff from 16 grassed and cropped watersheds were measured over the past decade. Six watersheds drained into two flood detention reservoirs, where phosphorus concentrations were also measured at the inflow, within the lake, and at the outflow over a two-year period, to assess the effects of agricultural management practices on water quality. Soluble and total phosphorus concentrations in runoff from the native grass (133 and 343 mgP m-3, respectively) and cropped watersheds (215 and 2423 mgP m-3, respectively) were similar to phosphorus concentrations at the inflows to the reservoirs. Adsorption, biological uptake, and suspended sediment settling reduced soluble and total phosphorus levels 75 and 93 percent, respectively, in outflow from the reservoir with the grassed drainage basin and 72 and 96 percent, respectively, for the cropped drainage basin reservoir. Mean annual chlorophyll aand Secchi depths classified both reservoirs as eutrophic, even though only small amounts of fertilizer phosphorus were applied in their watersheds. Chlorophyll a and Secchi depths predicted from flushing-corrected inflow phosphorus concentrations were within the 95 percent confidence intervals of trophic response curves. Although flushing-corrected inflow phosphorus concentrations from native grass were appreciably lower than from cropped land, all management practices contributed runoff capable of accelerating eutrophication of the reservoirs. |
| Remote Sensing of Off-Site Downstream Effects of Erosion in Freshwater Lakes and Reservoirs | Jerry C. Ritchie; Frank R. Schiebe; Charles M. Cooper | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 95 - 100 | Remote Sensing of Off-Site Downstream Effects of Erosion in Freshwater Lakes and Reservoirs | Off-site damage from soil erosion in freshwater lakes and reservoirs is an environmental concern worldwide. Suspended sediments are the most visible indicators of off-site damage and a major factor affecting water quality and biological activity in water bodies. A technique is needed to monitor the landscape and locate water bodies with significant suspended sediment concentrations. This paper describes a technique using remote sensing data from environmental satellites to estimate suspended sediment concentrations in lakes and reservoirs. Comparisons of water bodies on multiple Landsat scenes indicate reflectance from surface water is related to suspended sediment concentrations. Using satellite remote sensing, large segments of the landscape could be monitored quickly and efficiently to locate water bodies with significant suspended sediment concentrations. Conservation practices to reduce soil erosion and thus off-site damage from suspended sediments could be planned for the watersheds of water bodies with significant suspended sediment problems. |
| Lake Assessment Program: A Cooperative Lake Study Program | Steven A. Heiskary | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 85 - 94 | Lake Assessment Program: A Cooperative Lake Study Program | The Lake Assessment Program is a cooperative lake study program involving Minnesota Pollution Control Agency (MPCA) staff and local citizens. It was initiated in 1985 as a pilot program to fill the gap between the Citizen Lake Monitoring Program (Secchi disk monitoring) and intensive studies by MPCA and the Clean Lakes Program. Citizen involvement is the principal focus of the Lake Assessment Program. Citizens participate in sampling, watershed and lake review, defining the lake's history, and setting lake water quality goals. The Lake Assessment Program provides valuable information for the local citizens, MPCA, and others interested in protecting or improving the quality of a lake. Fifteen Lake Assessment Program studies have been completed. The Lake Assessment Program will be an integral part of Minnesota's Clean Water Partnership Program and U.S. Environmental Protection Agency's (EPA) Clean Lakes Program in Minnesota, providing information necessary to select projects and to communicate ideas about lake protection and restoration. An overview of this program is presented with examples of completed studies. Using an ecoregion framework in the goal-setting process will also be addressed. |
| Design and Evaluation of Eutrophication Control Measures for the St. Paul Water Supply | William W. Walker Jr.; Charles E. Westerberg; David J. Schuler; James A. Bode | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 71 - 83 | Design and Evaluation of Eutrophication Control Measures for the St. Paul Water Supply | In 1984, intensive lake and watershed studies were undertaken by St. Paul Water Utility to identify causes and remedies for taste-and-odor episodes that had plagued the supply in recent years. Water is derived from the Vadnais Lake Chain, and fed mainly by diversions from the Mississippi River and runoff from local watersheds. Early phases of the study implicated algal blooms in the storage lakes as the immediate cause of the taste-and-odor problems. Historical control schemes, including routine copper sulfate applications and dosing of various chemicals at the water treatment plant, had been largely unsuccessful. Following three years of collecting baseline data control measures were implemented to address the basic problem of nutrient enrichment. These controls targeted sources of phosphorus including diversions from the Mississippi River, runoff from urban watersheds, and recycling from lake bottom sediments. Specific control measures included: (1) selecting supply sources based upon chemical factors - phosphorus, silica, iron; (2) injecting iron chloride to inactivate orthophosphorus in waters pumped from the Mississippi River; (3) using wet detention ponds to reduce phosphorus loadings in runoff from urban watersheds; (4) aerating the hypolimnion - plus iron chloride injections in 1988. This paper discusses the design and evaluation of control measures and observed lake responses over the 1984-88 monitoring period. Results indicate substantial progress has been made toward reducing nutrient enrichment levels in the supply lakes as well as undesirable impacts on the water supply; these include taste-and-odor, trihalomethanes, and water treatment costs. The ongoing monitoring program will track lake responses and control (success) over a wider range of hydrologic conditions. |
| Effects of Nutrient Enrichment on the Florida Everglades | Thomas V. Belanger; Daniel J. Scheidt; John R. Platko II | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 101 - 111 | Effects of Nutrient Enrichment on the Florida Everglades | Since the 1970s, nutrient-enriched agricultural drainage water has been pumped into the Everglades Water Conservation Areas, markedly changing plant communities and oxygen regimes. The sawgrass plains and diverse aquatic sloughs that once dominated the area are gradually being replaced by more heterotrophic cattail stands. An oxygen budget study in Water Conservation Area-2A revealed diurnal oxygen levels, and variations were greatest in slough and sawgrass areas and minimal at the nutrient-enriched cattail site. Sediment oxygen demand was the major oxygen sink at all sites, while reaeration (sawgrass and cattail sites) and benthic algal production (slough site) were the major sources of oxygen. The slough algal mat areas represent important sites for marsh primary production and detrital processes. These areas function as feeding areas for fishes, invertebrates, and waterfowl, as well as important oxygen sources for adjacent sawgrass areas. Their elimination, therefore, could have serious ecological consequences. |
| A Test of the Effects of Lime on Algal Biomass and Total Phosphorus Concentrations in Edmonton Stormwater Retention Lakes | J. Babin; E. E. Prepas; T. P. Murphy; H. R. Hamilton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 129 - 135 | A Test of the Effects of Lime on Algal Biomass and Total Phosphorus Concentrations in Edmonton Stormwater Retention Lakes | Lime, calcium carbonate and/or calcium hydroxide were added eight times to three stormwater retention lakes in Edmonton from June to August 1988. The goal was to evaluate short-term effects of lime on algal biomass and phosphorus concentrations in rapidly-flushed systems - those designed with a water retention period of 0.25 to 0.5 yr. Most of the water flow occurs from May to September and varies greatly depending on annual precipitation. These lakes also provided an opportunity to evaluate lime treatment effects on hardwater lakes with unusually high sulfate and calcium concentrations (average summer concentrations were 334 and 65 mg/L, respectively). Within one week of applying at least 50 mg/L calcium hydroxide with or without calcium carbonate, chlorophyll a(used to estimate algal biomass) and total phosphorus concentrations decreased significantly (P < 0.05). In the lake treated solely with calcium carbonate (in doses of 50 and 100 mg/L), neither total phosphorous nor chlorophyll adecreased significantly (P > 0.05). Test results for lime controlling phosphorus levels and algal biomass in rapidly-flushed lake systems are promising. |
| A Littoral Interstitial Porewater (LIP) Sampler and Its Use in Studying Groundwater Quality Entering a Lake | David F. Mitchell; Kenneth J. Wagner; William J. Monagle; Gary A. Beluzo | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 121 - 128 | A Littoral Interstitial Porewater (LIP) Sampler and Its Use in Studying Groundwater Quality Entering a Lake | The performance of a modified hydraulic potentiomanometer termed a littoral interstitial porewater (LIP) sampler was evaluated in the field. Patterned after the hydraulic potentiomanometer designed by the U.S. Geological Survey, this tube sampler allowed rapid characterization of groundwater interaction with surface waters. The littoral interstitial porewater sampler facilitates characterizing groundwater quality variability along a lake shoreline, and is used to corroborate information obtained from watershed well sampling. Results were not significantly affected by various sampling protocols or analytical error. Significant changes in water quality parameters were caused by spatial factors, and these corresponded to different land use patterns on shorelines sampled. A significant correlation between the littoral porewater samples and adjacent well water samples was shown. Littoral interstitial porewater pumping rate did not empirically estimate seepage rates. Descriptive statistics of littoral porewater quality data from 15 Massachusetts lakes were given. The correspondence between land use, specifically residential development intensity, and porewater chemistry was documented. |
| Contaminant Residues in Fish from Tensas River National Wildlife Refuge | Parley V. Winger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 113 - 119 | Contaminant Residues in Fish from Tensas River National Wildlife Refuge | Tensas River National Wildlife Refuge, Madison Parish, Louisiana, consists of bottomland hardwood swamps interspersed with small lakes and bayous supporting a diverse assemblage of waterfowl, fish, and assorted species of game and nongame wildlife. Fish collected in the refuge in 1984-85 from areas receiving direct inflow from agricultural runoff contained from 5 to 10 μg/g total DDT (primarily DDE) and toxaphene (measured on a whole-body, wet-weight basis). These concentrations in fish, which were still high enough to pose a threat to fish-eating birds and wildlife, demonstrated that residues from past use of DDT and toxaphene in the area were still available for transport and uptake. In future water projects, the incorporation of structures to prevent contaminated runoff from entering the refuge should reduce waterborne contamination to the refuge. |
| Evaluating the Effectiveness of Best Management Practices to Reduce Agricultural Nonpoint Source Pollution | Thomas H. Johengen; Alfred M. Beeton; Dennis W. Rice | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 63 - 70 | Evaluating the Effectiveness of Best Management Practices to Reduce Agricultural Nonpoint Source Pollution | The Saline Valley project is one of 20 national projects sponsored by the U.S. Department of Agriculture (USDA) under the Rural Clean Water Program (RCWP) to evaluate methods of controlling agricultural non-point source pollution. The goals of this project were (1) to evaluate whether a voluntary approach using cost-share incentives would produce adequate participation by local farmers and (2) to reduce phosphorus loads from the area by 40 percent. Water quality has been monitored since 1981 using weekly grab samples and flow measurements. Trends in empirical relationships between concentration and discharge at three sampling stations were used to examine the effectiveness of best management practices (BMP). These relationships were highly variable among the sub-basins and years, and did not appear to correlate with areal estimates of BMP implementation. Overall, low participation within the project area hindered the ability to quantify changes in water quality resulting from BMP implementation and prevented the project from meeting its phosphorus reduction goals. |
| Simultaneous Nitrogen and Phosphorus Deficiency in Natural Phytoplankton Assemblages: Theory, Empirical Evidence, and Implications for Lake Management | Walter K. Dodds; Kirk R. Johnson; John C. Priscu | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 21 - 26 | Simultaneous Nitrogen and Phosphorus Deficiency in Natural Phytoplankton Assemblages: Theory, Empirical Evidence, and Implications for Lake Management | There is considerable support in the ecological literature for the theory that phytoplankton communities experience non-equilibrium conditions. Therefore, it is possible that not all species of an algal community are deficient in the same nutrient, challenging the belief held by some aquatic scientists and lake managers that phosphorus is the universal nutrient limiting phytoplankton growth in lakes. Simultaneous additions of NH4+ and PO43- were necessary to stimulate community photosynthesis - uptake of 14CO2 - during summer stratification in a number of northern Rocky Mountain lakes and reservoirs, whereas adding one nutrient had no significant effect on community photosynthesis. However, size-fractionated bioassays showed that additions of nitrogen alone stimulated photosynthesis of specific size classes of phytoplankton in these systems. The authors' data have the following implications for lake management: (1) phosphorus should not be assumed to be the only nutrient controlling photosynthesis; (2) simultaneous enrichment of nitrogen and phosphorus may be necessary to measurably increase community photosynthesis, especially in nutrient dilute systems; and (3) adding NH4+ may cause changes in phytoplankton community structure without changing community primary production. |
| Causes and Consequences of Blue-Green Algal (Cyanobacterial) Blooms | Andrew R. Klemer; Allan E. Konopka | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 9 - 19 | Causes and Consequences of Blue-Green Algal (Cyanobacterial) Blooms | In lakes and reservoirs, productivity and biomass responses to nutrient loading are fairly predictable; resultant changes in phytoplankton taxonomic composition are not. Whether enrichment leads to dominance by procaryotic or by eucaryotic phytoplankton is important to lake trophic structures, to ecosystem modelers, and to lake managers. Much of the uncertainty about the effects of enrichment on phytoplankton composition stems from an inadequate understanding of how nuisance bloom-formers succeed in dominating plankton assemblages. The authors contend that investigations of nutrient effects on cyanobacterial buoyancy regulation provide a basis for understanding patterns of cyanobacterial dominance during the course of eutrophication as well as during seasonal successions in stratified, eutrophic lakes. Cyanobacterial dominance in the surface layers of enriched lakes should be more pronounced in HCO3-rich waters where synthesis of the cellular components involved in buoyancy regulation is not limited by nitrogen, phosphorus, or carbon. In mildly acidic and other low-carbon waters, carbon limitation of buoyancy regulation deters nuisance bloom formers, but not non-gas-vacuolate cyanobacteria. The authors also suggest that restoration by artificial mixing or by biomanipulation is less likely to succeed in HCO3-rich than in softwater basins. |
| The Ohio Lake Condition Index: A New Multiparameter Approach to Lake Classification | Robert D. Davic; Jeffrey E. DeShon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 1 - 8 | The Ohio Lake Condition Index: A New Multiparameter Approach to Lake Classification | A new multiparameter lake assessment protocol, the Ohio Lake Condition Index (Ohio LCI), was developed by the State of Ohio to comply with the 305(b) guidelines in the Water Quality Act amendments of 1987. Thirteen in-lake parameters were assessed for each of Ohio's 417 publicly owned lakes. Both monitored data and evaluated information based on responses to a questionnaire were included in the assessment process. Raw data were transformed into subindex points for summation into a final numerical Lake Condition Index score. Sets of parameters were identified to determine whether or not designated uses and the goals of the Clean Water Act were being met. Applications of the Ohio Lake Condition Index are discussed, including using it to target lakes affected by nonpoint source pollution. The Lake Condition Index protocol can be modified to accommodate revisions to water quality standards and changes in a state's water quality management objectives for lakes. The authors question the appropriateness of reporting the status of lake condition based exclusively on the concept of trophic state. |
| Algal Nutrient Deficiency: Growth Bioassays versus Physiological Indicators | Ann L. St. Amand; Patricia A. Soranno; Stephen R. Carpenter; James J. Elser | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 27 - 35 | Algal Nutrient Deficiency: Growth Bioassays versus Physiological Indicators | The ability of nutrient enrichment bioassays versus physiological indicators to detect ecosystem changes in nutrient cycling were compared. Field data spanned four years in three lakes, two of which were subjected to fish manipulations in year two. The manipulations changed phytoplankton and zooplankton assemblages and nutrient cycling. Phosphorus and nitrogen enrichments (phosphorus enrichment bioassay (PEB), nitrogen enrichment bioassay, nitrogen plus phosphorus enrichment bioassay, specific alkaline phosphatase activity, ammonium enhancement response, and total nutrients (total phosphorus, total nitrogen) were measured before and after the manipulations. Although physiological indicators were often more sensitive, nutrient enrichments and physiological indicators both led to the same conclusions regarding changes in nutrient cycling. Total nutrients did not respond to manipulation. Physiological indicators measure the extant algal assemblage, are rapidly assayed, can be run more frequently than nutrient enrichments, and lead to the same conclusions as nutrient enrichment bioassays. |
| Bacteriological Water Quality in Vermont Agricultural Watersheds Undergoing Land Treatment | Donald W. Meals | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 53 - 62 | Bacteriological Water Quality in Vermont Agricultural Watersheds Undergoing Land Treatment | Bacteria are often important indicators of nonpoint source water pollution. Runoff from farmland and agricultural activities such as animal waste management, feedlots, and grazing are the principal sources of bacteria to surface waters. Fecal coliform and fecal streptococcus levels have been monitored in four Vermont agricultural watersheds for eight years as part of the LaPlatte River Watershed Project. This project is a long-term monitoring program designed to evaluate the effects of implementing best management practices on water quality. Bacterial densities recorded in the monitored streams and in runoff from specific agricultural practices are reported. While levels of fecal streptococci in the streams have declined significantly since implementing land treatments, bacterial densities continue to exceed water quality criteria 20 to 30 percent of the time, particularly in summer. Bacterial densities in the streams appear related to agricultural activities within their watersheds such as corn production, pasturing, and animal density. |
| The Relationship Between Taste and Odor Problems and Lake Enrichment from Kansas Lakes in Agricultural Watersheds | Joseph A. Arruda; Carla H. Fromm | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 45 - 52 | The Relationship Between Taste and Odor Problems and Lake Enrichment from Kansas Lakes in Agricultural Watersheds | Taste and odor are frequently cited problems in Kansas water supply lakes in agricultural watersheds. This study assesses the relative magnitude of summer lake water taste and odor as it relates to lake enrichment levels in six representative Kansas lakes. Mean chlorophyll concentrations ranged from 3.05 μg/L to 16.63 μg/L. Algal species included various flagellates, green algae, and diatoms. Cryptomonaswas common in all lakes. While surface and bottom water odors increased during the summer, bottom water odors persisted longer, until lake destratification. Anabaenaand Cyclotellawere most often associated with lake water odor. While bottom water odor ranking was not associated with lake trophic state (P = 0.21), surface water odors were associated with lake trophic state (r = 0.81, P = 0.05). |
| Using a Special Purpose Unit of Government to Manage Lakes | Lowell Klessig; Basil Sharp; Richard Wedepohl | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 5 | 1 | 1989 | 37 - 44 | Using a Special Purpose Unit of Government to Manage Lakes | In 1974, the Wisconsin Legislature recognized that many lakes needed more intensive management than could be provided by either the state's general pollution control efforts or the voluntary efforts of property owners' associations. The Legislature passed legislation enabling property owners to form a special purpose unit of government to manage a local lake. This article describes the history and activities of Wisconsin lake districts. Particular attention is paid to the differentiation of function between federal, state, and county/municipal governments - general purpose units - and the special purpose lake district. Data from a recent survey of 79 lake districts showed the most popular activities are mechanically harvesting aquatic vegetation, 57 percent; stocking fish, 48 percent; promoting boating and skiing regulations, 37 percent; chemically controlling macrophytes, 34 percent; controlling algae, 33 percent; patrolling water safety, 28 percent; promoting zoning, 25 percent; inspecting septic tanks, 25 percent; and providing public access, 25 percent. Such management efforts indicated lake districts have become a significant institution in the management of Wisconsin lakes. |
| Agricultural Nonpoint Source Controls: Implications of Recent Legislation for Scott County, Minnesota | Steven R. McComas; Peter J. Beckius | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 231 - 236 | Agricultural Nonpoint Source Controls: Implications of Recent Legislation for Scott County, Minnesota | Interview responses from a 1983 targeted survey of 50 farmers with highly erodible cropland in Scott County, Minnesota, indicated a majority, 83 percent, would decline to participate in a voluntary state cost-sharing program for erosion reduction because of interferences with crop rotation, unsuitability of practices with their farming operations, inadequate cost sharing, and cash flow problems. The passing of a federal act, the 1985 Farm Bill (the Food Security Act), appeared to have the power to require conservation on highly erodible cropland until relaxation of provisions in 1988 weakened its conservation guidelines. However, another program, the Minnesota Surface Water Management Act, has required local units of government to prepare and enforce management plans for surface water quantity and quality within the boundaries of a watershed. This law will require rules and regulations that will reduce soil loss from erodible areas. It appears that for effective conservation on erodible farmlands, and thus a reduction in agricultural nonpoint source pollution, programs will have to be mandatory rather than voluntary. Conservation initiatives will have to originate from the local level with local input and local enforcement. |
| Seston Sedimentation in a Tropical Reservoir | Christopher F. Knud-Hansen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 221 - 230 | Seston Sedimentation in a Tropical Reservoir | Wet and dry season epilimnetic losses of particulate carbon, nitrogen, phosphorus, iron, and total suspended solids were determined for a small, mesotrophic reservoir in Lago Yure, Honduras. Measured particulate carbon, nitrogen, phosphorus, and iron losses varied between 364-1,621 mg/m2/day, 42-118 mg/m2/day, 4-16 mg/m2/day, and 54-349 mg/m2/day, respectively, depending upon allochthonous loading. Particulate carbon to nitrogen ratios in the sedimented material consistently ranged from about 9 to 11, approximating epilimnetic seston. Deposition rates of particulate phosphorus relative to concentrations in the epilimnion were quite low, indicating rapid mineralization and recycling. Phosphorus sedimentation rate coefficients (σ) calculated from both phosphorus budget and sediment trap data indicated internal phosphorus loading (5.2 mg/m2/day) only during the dry season. |
| The Development of a Phosphorus Management Strategy for Two Piedmont Reservoirs in North Carolina | Randall C. Dodd; James F. Smith; J. David Vogt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 243 - 252 | The Development of a Phosphorus Management Strategy for Two Piedmont Reservoirs in North Carolina | Phosphorus loading to the recently impounded B. Everett Jordan and Falls of the Neuse reservoirs in North Carolina has been the subject of public debate and research for many years. A strategy was developed in 1983 to reduce phosphorus inputs from both point and nonpoint sources. Monitoring and research results, nutrient budget analyses, application of simple nutrient and chlorophyll amodels, and knowledge of the emerging technology of biological phosphorus removal have led to the development of a modified strategy for dealing with point sources. This includes effluent limits (total phosphorus = 2 mg/L as a quarterly average) for all new and expanding dischargers and all existing dischargers greater than 50,000 gallons per day (gpd) in both basins. |
| Cost-Sharing Soil Conservation Practices: Economic Pros and Cons from a Lake Management Perspective | Thomas M. Skelly; William J. Hinsman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 237 - 242 | Cost-Sharing Soil Conservation Practices: Economic Pros and Cons from a Lake Management Perspective | This paper compares costs and benefits of strategies to control watershed erosion and sedimentation in Lake Springfield, Illinois, with standard dredging operations to remove soil buildup once it has occurred. Lake Springfield is a 1,635-ha body of water maintained by the city of Springfield for drinking and cooling water, and residential and recreational use. Sedimentation has reduced its storage capacity by 13 percent since the lake was built in 1935. Since 1983 the city has funded soil conservation programs in the lake's watershed. These programs are best management practices (BMPs), and include no-till planting methods, as well as the construction of conservation structures such as terraces, ponds, and grassed waterways. In 1983 the city purchased a no-till planter for $10,000; the equipment prevented soil from entering the lake at a cost of $1.05/metric ton. Cost-sharing grants totalling $105,000 to assist land owners in building conservation structures prevented soil from entering the lake at a cost of at least $6.73/metric ton. In contrast, the cost of standard dredging operations to remove soil already in the lake is $5.16/metric ton. Results of the analysis indicated that reduced tillage is very effective for achieving conservation goals and can be implemented at reasonable cost. On the other hand, BMPs funded under the city's cost-sharing program proved more expensive than standard dredging by at least $1.50/metric ton. Although preventive management has some public relations and aesthetic benefits, it is not cost effective because major sediment inputs occur during infrequent, large storms that cannot be withstood by most BMP structures. |
| A Research Scientist's Perspective on the Management of Kesterson Reservoir: A Marsh Contaminated with Selenium-Rich Agricultural Drain Water | Alex J. Horne | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 187 - 198 | A Research Scientist's Perspective on the Management of Kesterson Reservoir: A Marsh Contaminated with Selenium-Rich Agricultural Drain Water | The unexpected discovery of deformed bird embryos linked to selenium toxicity at Kesterson Reservoir required rapid response. Research on groundwater hydrology, geochemistry, and ecology was initiated. Selenium input was stopped and a phased approach was proposed to detoxify the remaining inventory. Clean-up methods were planned, beginning with the simplest. These proposed techniques began with in situselenium immobilization under wet (anoxic) conditions and ended with scraping off the contaminated topsoil. Cost estimates ranged from $5 million to $200 million. Recommendations to managers based on research findings were contradictory. Many agency scientists, influenced perhaps by policy concerns, disagreed with others using a strictly scientific approach. Cost-effective management was jeopardized by disagreements on accuracy and precision of data. At public hearings scientific witnesses were unable under oath to agree on apparently straightforward data. Conclusions reached by university researchers derived from field and laboratory experiments with micro- and mesocosms were not accepted by agency staff. University research investigators emphasized experimental results over field data collections. An opposite view was taken by most agency staff. Improved advice to management would result if both agency and research scientists recognized the legitimacy of their different approaches and reached a consensus before public hearings or other decision points, which are often heavily influenced by lawyers. Such a consensus requires rapid analysis and release of all relevant data. Lake and wetlands managers can assist by facilitating data-based workshops that allow groups to interact on a non-adversarial basis. |
| Selenium Levels in Biota from Irrigation Drainwater Impoundments in the San Joaquin Valley, California | Douglas A. Barnum; David S. Gilmer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 181 - 186 | Selenium Levels in Biota from Irrigation Drainwater Impoundments in the San Joaquin Valley, California | Waterfowl, fish, invertebrates, and plants were collected from impoundments used for evaporating subsurface irrigation drainwater in Kings and Kern counties, California. Specimens were analyzed for trace elements with emphasis on selenium. Dry weight concentrations of total selenium ranged from 2.5 to 17 μg/g in wigeongrass, Ruppia maritima; 7.6 to 30 μg/g in water boatmen, Corixidae; 12 to 40 μ/g in mosquitofish, Gambusia affinis; 86 to 100 μg/g in eared grebe, Podiceps niqricollis, livers; 14 to 120 μg/g in ruddy duck, Oxyura jamaicensis, livers; and 6.8 to 48 μg/g in northern shoveler, Anas clypeata, livers. Concentrations of dissolved selenium ranged from less than 1 to 37 μg/L during a 12-month period for inflows to the drainwater evaporation ponds. |
| Limnological and Ecological Considerations for Hydropower Development in Honduras | Ernesto Vargas; Peter D. Vaux | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 213 - 220 | Limnological and Ecological Considerations for Hydropower Development in Honduras | The recently commissioned EI Cajon dam is the third major hydroelectric project to be built in Honduras, but the first to include detailed limnological and ecological studies, in the near future, ecological and sociological studies may play a significant role in deciding the next site for hydropower generation, since initial evaluations of three possible future sites suggest that their economic value is similar. The authors describe limnological and ecological aspects of existing and future hydroelectric projects in Honduras, and then use the example of watershed management in the EI Cajon basin to illustrate some of the problems associated with impoundment planning and management in Honduras. |
| The EI Cajon Reservoir: Developing Management Strategies for a Tropical Impoundment | Peter D. Vaux; Ernesto Vargas; Ana Diaz; Adela Flores | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 199 - 211 | The EI Cajon Reservoir: Developing Management Strategies for a Tropical Impoundment | In 1984, a 94 km2 reservoir started to form behind the highest arch dam on the American continent, EI Cajon in Honduras. Pre-impoundment programs established to assess the environmental aspects of this hydroelectric project have developed into a post-impoundment research unit that is undertaking management-oriented studies on the reservoir and its watershed. Information from this research provides an excellent case history of the evolution of a tropical reservoir and associated management challenges. Accumulation of hydrogen sulfide in the anoxic hypolimnion has resulted in some corrosion problems in the power generation facility. The fisheries, which appear to have a substantial potential for contributing to employment and food supply in the region, are currently underexploited. However, as the regional social infrastructure develops, utilization of the fisheries production is expected to increase. As population pressure in the EI Cajon basin increases, the economic and environmental consequences of elevated rates of soil erosion and sediment loading to the reservoir are likely to become increasingly important. This paper summarizes aspects of the limnology and ecology of the EI Cajon Reservoir and discusses the potential for developing management strategies designed to promote the multiple-use nature of this resource. |
| Long-term Effects of Dredging on Phosphorus Availability from Liberty Lake Sediments | Barry C. Moore; William H. Funk; Jeffrey Lafer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 293 - 301 | Long-term Effects of Dredging on Phosphorus Availability from Liberty Lake Sediments | The results of dredging at Liberty Lake offer some valuable lessons for the conduct of sediment removal operations for lake restoration objectives. It was planned that approximately 50 ha were to be dredged at Liberty Lake. Differing dredge patterns were produced by two different contractors who performed the actual work, which included the removal of over 4 105 m3 of sediment material. In Area 1, deeply dug trenches were separated by undredged rows, while the bottom contour was more uniform in Area 2. The trenching pattern resulted in an actual dredged area of only about 21 ha. Because of slumping of undredged material into the trenches, and because of the remaining pool of high-phosphorus sediments, the dredging at Liberty Lake, especially in Area 1 was not as successful in reducing internal phosphorus loading as anticipated. In addition, macrophyte control from the dredging was not realized in Area 1, as macrophyte regrowth has been rapid. Some considerations for sediment removal in lake restoration projects are suggested. |
| A Water Collecting System for Under-Ice Sampling | Robert J. Danehy; Michael B. Bonoff; Robert F. Cusimano; Michael A. Reese | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 287 - 291 | A Water Collecting System for Under-Ice Sampling | This paper describes a water sample collection system for taking high-quality samples at all depths and in severe climates. The system can be used for obtaining samples under ice, in open water, or from streams and rivers. The collection system consists of a diaphragm pump, an integration chamber, and a boom. The water sample is exposed only to Tygon tubing and acrylic plastic before storage in aliquots, The integration chamber is easy to rinse between samples. Syringe and bulk water aliquots from the integration chamber can be subsampled the same way they are from a Van Dorn bottle. Duplicate samples precision is demonstrated using samples from three Adirondack lakes analyzed for pH, conductivity, acid neutralizing capacity, and dissolved inorganic carbon. Conductivity values of blank samples of deionized water, and a comparison of analysis and duplicate precision data for field samples collected through the ice and in open water using a Van Dorn bottle, are also presented. |
| Potential Links Between Eutrophication and the Formation of Carcinogens in Drinking Water | Nancy S. Palmstrom; Robert E. Carlson; G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 1 - 15 | Potential Links Between Eutrophication and the Formation of Carcinogens in Drinking Water | Eutrophication in lakes and reservoirs is a recreational problem and a drinking water quality problem. A major concern is trihalomethane (THM) formation from the reaction of chlorine, a disinfectant, with organic matter in natural water during drinking water treatment. Trihalomethanes, such as chloroform, are known or suspected carcinogens. Algae and allochthonous humic substances are known contributors to the THM precursor pool. Other in-reservoir precursor sources, macrophytes, and sediments, have not been investigated. The authors examined precursor generation in an Ohio water supply reservoir. A three-year input-output study demonstrated that 30 percent of the precursors entering the treatment plant were generated within the reservoir. Laboratory experiments revealed that macrophytes and sediments produce THM precursors. Estimated THM precursor contributions to the reservoir from macrophyte growth and sediment release were small, but algal productivity and macrophyte decomposition may contribute more than one-third of the precursors during the summer. |
| Nonpoint Pollution and Watershed Management: A Remote Sensing and Geographic Information System (GIS) Approach | Kenneth J. DelRegno; Samuel F. Atkinson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 17 - 25 | Nonpoint Pollution and Watershed Management: A Remote Sensing and Geographic Information System (GIS) Approach | Dallas Water Utilities (DWU) uses Landsat multispectral remote sensing data for determining historical land use changes in watersheds and identifing critical areas where water quality protection efforts should be maximized. Water quality monitoring data are used to document actual impacts to reservoirs from areas predicted by remote sensing analyses to be adversely affected. Additionally, DWU monitors ail National Pollutant Discharge Elimination System (NPDES) and Texas Water Commission waste discharge permit applications and plant performance histories. This ensures that DWU reviews point source discharges and assists the Texas Water Commission in their monitoring functions. DWU cooperates with other area agencies to promote regional wastewater treatment as an alternative to numerous package plants which have a history of poor wastewater management. Point source management should result in lower total nutrient loads to reservoirs. Remote sensing technology provides one of the most efficient methods of addressing nonpoint source pollution and ultimately reducing sedimentation and nutrient loads to the reservoirs. |
| Interaction of Nitrogen/Phosphorus and Silica/Phosphorus Ratios in Determining Phytoplankton Species Composition and Abundance in Lake George, New York | Carol Desormeau Collins | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 261 - 269 | Interaction of Nitrogen/Phosphorus and Silica/Phosphorus Ratios in Determining Phytoplankton Species Composition and Abundance in Lake George, New York | Lake George, New York, is generally considered an oligotrophic phosphorus-limited lake. Yet, the supply and recycling rates of nitrogen and silica may also be critical in regulating phytoplankton productivity, species composition, and abundance. Biweekly phytoplankton bioassays were conducted in 1986 and 1987 at three stations in Lake George to measure the response of natural assemblages to enrichment gradients of nitrogen/phosphorus (N/P) and silica/phosphorus (Si/P). Chlorophyll aconcentration, cell number, and species composition were measured throughout the seven to nine day experiments. Limitation by phosphorus, nitrogen, and dissolved silica were observed in the bioassays. Response surface analyses of the bioassay results indicate important interaction of these ratios in determining species composition and seasonal trends in nutrient limitation. |
| Assessment of Water Quality in Corps of Engineers Reservoirs | Robert H. Kennedy; Robert F. Gaugush | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 253 - 260 | Assessment of Water Quality in Corps of Engineers Reservoirs | Concern over freshwater quality and emphasis on developing improved methods for managing existing water resource projects led the U.S. Army Corps of Engineers to initiate several water research programs. Compiling and analyzing a Corps-wide water quality database for reservoirs and tailwaters was one such effort: These data are being supplemented with subjective information about enhancement needs solicited from field offices. The survey included more than 750 reservoirs, locks, and dams, and dry dams. Most frequently cited during the survey was the need to improve tailwater conditions - particularly low dissolved oxygen levels, temperature extremes, and the presence of reduced metals - reduce nutrient concentrations, and ameliorate conditions associated with the eutrophication process. A preliminary investigation indicated southeastern reservoirs exhibited (1) lower total nitrogen concentrations than the national average; (2) significant longitudinal gradients in water quality; and (3) turbidity as a probable constraint to primary production. |
| A Note on Algal Toxins in Wisconsin Waters Experiencing Blue-green Algal Blooms | William C. Sonzogni; Wyatt M. Repavich; Jon H. Standridge; Richard E. Wedepohl; James G. Vennie | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 281 - 285 | A Note on Algal Toxins in Wisconsin Waters Experiencing Blue-green Algal Blooms | Certain blue-green algae commonly found in lakes can produce potent toxins during blooms. In Wisconsin there were several incidents over the years when wildlife and domestic deaths were attributed to algal toxins; however, little information existed on how widespread these toxins were in Wisconsin's many lakes and ponds. Thus, a study was undertaken to determine the incidence of measurable toxins in Wisconsin waters. Samples were collected from 86 lakes and ponds, the algae identified by genus, and the toxicity tested using a mouse bioassay. In 25 lakes toxins were present during bloom conditions. Lakes with toxins were found in both the southern and northern portions of the state. The results indicated toxic blooms were not uncommon in Wisconsin, and that algal toxins may be a more critical lake management issue than generally realized. |
| Lake Aerator Effect on Temperature Stratification Analyzed by “MINLAKE†Model | K. Zic; H. G. Stefan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 85 - 90 | Lake Aerator Effect on Temperature Stratification Analyzed by “MINLAKE†Model | The paper deals with the prediction of the vertical temperature profiles in a stratified lake during the operation of an air bubble aeration system. The use of such systems is widespread and their effect on water quality very significant. They are installed for a variety of purposes and act as aerators (increasing dissolved oxygen), mixing devices, and often unintentionally as nutrient pumps and local destratification devices. It is not easy to predict the total impact of an air bubble system installed in lake. To gain a better appreciation of its effect, a model can be developed to simulate the flow induced by an air bubble system in a stratified lake. If such a model is incorporated into a dynamic water quality model, the cumulative synoptic interaction between the air bubble system and lake water quality can be simulated. Since lake destratification is not instantaneous, a dynamic model can simulate the interactions of continuous inputs of water, energy, and materials from the watershed and the atmosphere while the air bubble system is in operation. This can assist in the sizing and selection of such systems. This paper sketches the nearfield and farfield computer models available and illustrates the progressive destratification by an air bubble system in a temperature-stratified lake with the aid of the computer simulation. The nearfield computer model called BUBBLES treats the mixing in the vicinity of the air bubble plume. The farfield computer model called MINLAKE is for natural lake temperature stratification. The combined model is applied to Lake Calhoun (Minneapolis, Minnesota) for illustration. |
| Development of the Minnesota Lake Water Quality Management Model “MINLAKE†| Michael J. Riley; Heinz G. Stefan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 73 - 83 | Development of the Minnesota Lake Water Quality Management Model “MINLAKE†| A computer model has been developed that simulates several water quality parameters in a stratified lake during the main growth season. The model is process oriented and simulates heat transfer, light penetration, mixing by wind and natural convection, inflow and outflow, settling of particles, and several biological and chemical processes related to primary productivity. In the simulation, the lake is subdivided into layers of variable thickness. The timestep of the simulation is one day. Input to the simulation includes weather parameters, lake morphometry and inflow rate, and quality. Output consists of daily vertical distribution of water temperature, dissolved oxygen, suspended solids, up to three forms of plytoplankton, and up to three forms of phosphorus. The model is designed as a management tool to test lake treatment alternatives in planning lake restoration projects. The structure of the model allows individual lake treatment submodels to be inserted into the model without changing the existing model nor restricting the complexity of the lake treatment submodel. Simulation subroutines are being developed for several typical lake water quality management techniques such as aeration, destratification, inflow treatment or diversion, and sediment nutrient inactivation. Applications of the model to two Minnesota lakes with two different lake restoration alternatives are presented. |
| Evaluating Water Quality Effects of Lake Management in Florida | Forrest E. Dierberg; Vincent P. Williams; William H. Schneider | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 101 - 111 | Evaluating Water Quality Effects of Lake Management in Florida | Data from a total of 43 Florida lakes were evaluated to determine impacts on water quality by comparing trophic state indexes (TSIs) before and after one or more restoration practices. Of the 43, only 7 possessed data bases complete enough to draw conclusions. Three drawdown lakes showed little change in trophic state indexes, and two lakes stocked with grass carp to control vegetation also indicated only minor change. One lake where a sewage effluent discharge was removed showed statistically significant decreases in trophic state indexes within two years following diversion. An isolated cove of another lake exhibited marked improvement in Secchi transparency following suspended solids removal through detention-filtration-wetlands treatment of stormwater runoff. This significantly decreased the average trophic state index. Inappropriate statistical design and the lack of a long-term commitment to sample Florida's restored lakes limit evaluation of long-term water quality responses to various restoration techniques. More robust statistical approaches in evaluating lake restoration are needed. An approach to long-term evaluation of lake enhancement/restoration measures is presented. |
| The Eutrophication of Lake Okeechobee | Daniel E. Canfield Jr.; Mark V. Hoyer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 91 - 99 | The Eutrophication of Lake Okeechobee | Average annual total phosphorus concentrations in Lake Okeechobee increased from 0.049 mg/L in 1973 to 0.098 mg/L in 1984. The increases in total phosphorus concentrations were not correlated to external phosphorus inputs, but to changes in lake water levels. It is proposed that the flooding of marshes and exposed lake bottom primarily caused increased total phosphorus concentrations, but that the resuspension of bottom sediments by wind action may also be a major factor influencing in-lake total phosphorus concentrations. Reducing phosphorus inputs by 40 percent as proposed by the Lake Okeechobee Technical Advisory Committee (LOTAC) will not significantly improve water quality in Lake Okeechobee. Average total phosphorus concentrations will not decline significantly. Chlorophyll a concentrations and Secchi transparencies are not correlated to total phosphorus concentrations so massive expenditures of public funds to reduce nutrient inputs will not protect long-term water quality at Lake Okeechobee. |
| Utility of Layer Aeration for Reservoir and Lake Management | R. W. Kortmann; M. E. Conners; G. W. Knoecklein; C. H. Bonnell | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 35 - 50 | Utility of Layer Aeration for Reservoir and Lake Management | Layer aeration (U.S. Pat. 4,724,086) is a process that manipulates the heat and oxygen mass of a thermally stratified water body to create a desirable physical/chemical depth profile. Unlike destratification, layer aeration creates an aerobic cool, isothermal layer(s) bounded by several functional thermoclines. The process also enhances stratification and habitat structure. Unlike hypolimnetic aeration, the method redistributes available heat and oxygen and avoids the potentially adverse effects of nitrogen super-saturation, increased diffusional transport to the epilimnion, and metalimnetic anoxia. This paper discusses the chemical, physical, and biological effects of layer aeration in two Connecticut lakes. In Mulberry Reservoir, layer aeration reduced summer phosphorus accumulation by over one-third of pretreatment levels and improved hypolimnetic oxygen levels. Application to Glen Reservoir lowered ferrous iron concentrations and improved dissolved oxygen concentrations. Although further research is needed to document long-term benefits, layer aeration provides another option for treating systems for hypolimnetic oxygen depletion and related symptoms. Implications for managing recreational lakes and water supply reservoirs are discussed. |
| Internal Phosphorus Loading and Alum Effectiveness in Shallow Lakes | Eugene B. Welch; Curtis L. DeGasperi; Demitrius E. Spyridakis; Thomas J. Belnick | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 27 - 33 | Internal Phosphorus Loading and Alum Effectiveness in Shallow Lakes | Internal phosphorus loading in shallow aerobic lakes appears to be controlled by iron redox, much as it is in deep, stratified anaerobic lakes. Lack of stratification in shallow lakes, permitting greater oxygen transport to sediments than in stratified lakes, may be offset by higher temperature; this promotes greater demand for electron acceptors (O2 and NO3) and anoxic conditions at the sediment-water interface, as well as high pH that can maintain phosphorus in a soluble state under oxic conditions. Thus, it is not surprising that alum treatments in shallow lakes have been rather successful, with results lasting for more than a year. Of the nine treatments of shallow lakes for which data are adequate for evaluation, four can be considered unsuccessful (three of these failures were due to other sources of phosphorus). Treatment longevity is known for only one lake, however. If an alum longevity of four to five years turns out to be typical for shallow lakes, alum could be less cost effective than in deeper, stratified lakes, where longevity usually exceeds a decade. Possible control of other mechanisms of internal phosphorus loading (high sediment fractions of weakly sorbed phosphorus and overwintering buoyant blue-green algae) are also discussed. |
| The Effects of a Continuous Application of Aluminum Sulfate on Lotic Benthic Invertebrates | Richard Barbiero; Robert E. Carlson; G. Dennis Cooke; Alice W. Beals | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 63 - 72 | The Effects of a Continuous Application of Aluminum Sulfate on Lotic Benthic Invertebrates | A continuous dose of aluminum sulfate was applied to the Cuyahoga River 500 m upstream of Lake Rockwell, a northeastern Ohio reservoir, to decrease phosphorus loading. After one week of treatment benthic invertebrates were eliminated at a site 60 m downstream from the application site, possibly through toxicity of intermediate forms of aluminum, and/or from oxygen depletion in the floe, catastrophic drift induced by low pH or aluminum toxicity and the treatment acting as a partial barrier to drift. Small numbers of invertebrates returned to the site three weeks after the application was terminated. The alum floe accumulation seemed to favor the re-establishment of oligochaetes. Downstream sites had reduced numbers of invertebrates, particularly chironomids, after five weeks of treatment, perhaps caused by the alum treatment. Continuous applications of alum may be more toxic than single-dose treatments because of the continuous presence of transitory forms of aluminum. |
| Lime Treatment of a Hardwater Lake to Reduce Eutrophication | T. P. Murphy; K. G. Hall; T. G. Northcote | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 51 - 62 | Lime Treatment of a Hardwater Lake to Reduce Eutrophication | Lime addition was evaluated as a lake rehabilitation technique in Frisken Lake, a naturally eutrophic hardwater lake in British Columbia. Adding 39 tonnes of calcium hydroxide in 1983 and 1984 precipitated more than 85 to 95 percent of the chlorophyll aand 89 to 96 percent of the soluble reactive phosphorus from the epilimnion. The lake was not treated in 1985 but chlorophyll aconcentrations were less than those observed prior to lime treatment. Apparently lime addition did not induce phosphorus limitation; soluble reactive phosphorus concentrations in 1984 were never less than 35 μg/L. After lime treatment, phosphorus was adsorbed to calcite in the epilimnion but not in the hypolimnion; moreover, the monitoring data indicated all the precipitated phosphorus redissolved. The additional calcium carbonate precipitate may redissolve and reprecipitate as conditions change; thus, a long-term mechanism for continual algal removal was established. |
| Bioaccumulation of Selenium in Aquatic Ecosystems | Richard S. Ogle; Kurt J. Maier; Peter Kiffney; Michael J. Williams; Anne Brasher; Larry A. Melton; Allen W. Knight | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 165 - 173 | Bioaccumulation of Selenium in Aquatic Ecosystems | Elevated levels of selenium have resulted in the degradation of several ecosystems and have been linked to reproductive impairment in important fish and waterfowl populations in several lakes and reservoirs, indicating the need for a better understanding of the bioaccumulation of selenium by aquatic organisms. Because space limitations prevent an exhaustive review, this paper focuses on the processes and mechanisms of bioconcentration and biomagnification. Comparative uptake and accumulation of selenite, selenate, and selenomethionine are examined, as well as the relative importance of waterborne and foodborne exposure. The observed toxicity of selenium in lakes and reservoirs is briefly discussed. Finally, this information is summarized, pointing out key trends in the uptake and accumulation of selenium. Perhaps the most important information generated by this review involves comparative metabolism of selenite and selenate; selenite is readily reduced and metabolized, while reduction and metabolism of selenate appears to be limited. A knowledge of the processes and factors influencing selenium bioaccumulation in aquatic organisms will be essential in the development of management strategies and treatment methods that can be used to ameliorate selenium contamination problems. |
| The Selenium Problem in Lentic Ecosystems | K. J. Maier; R. S. Ogle; A. W. Knight | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 155 - 163 | The Selenium Problem in Lentic Ecosystems | Selenium, an essential trace element, exists in elevated concentrations in several aquatic systems and is apparently responsible for mortality, teratogenesis, reduced reproduction, and decreased populations observed in fish and waterfowl communities. Adverse impacts associated with increasing selenium levels are derived largely from anthropogenic mobilization of selenium in the environment. This paper reviews briefly selenium in aquatic ecosystems, discussing selenium chemistry, cycling, known biological impacts, toxicology, and several potential solutions to the selenium problem. Awareness and understanding of selenium dynamics in aquatic systems is necessary to avoid future problems and manage present ones. |
| Retention of Standing Timber for Fish and Wildlife Habitat in Reservoirs | Jeffrey C. Laufle; Richard A. Cassidy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 271 - 279 | Retention of Standing Timber for Fish and Wildlife Habitat in Reservoirs | The question of whether to maintain] standing timber in an Oregon multipurpose reservoir constructed by the U.S. Army Corps of Engineers was evaluated by project managers and debated by the community in which the reservoir was located. Although the practice has been accepted in other parts of the country, it was a relatively new idea for the Corps in the Pacific Northwest. Issues that were considered included impact on fish and wildlife habitat, recreation, boater safety, water quality, and debris removal. Evaluation based on experiences in other reservoirs and cost-benefit analysis indicated that fish and wildlife habitat would be enhanced; boating, recreation, and water quality would not be adversely affected; and the community would benefit financially over the 50-year life of the project, even taking into account the cost of debris removal. Community objections were aired and resolved, and the U.S. Army Corps of Engineers directed that 245 acres of standing timber in the reservoir basin be retained. |
| Reproduction in Black-Crowned Night-Herons Fed Selenium | Gregory J. Smith; Gary H. Heinz; David J. Hoffman; James W. Spann; Alexander J. Krynitsky | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 175 - 180 | Reproduction in Black-Crowned Night-Herons Fed Selenium | Agricultural and industrial practices can produce wastewater that contains high concentrations of selenium, a naturally-occurring trace element. Selenium entering aquatic systems through wastewater inflow can accumulate in aquatic food chains to levels that may be toxic to fish and wildlife species. Mallard reproduction is known to be adversely affected by 10 ppm selenium in the diet (containing 7-10 percent moisture, in the form of selenomethionine); however, hatching success of eggs laid by black-crowned night-herons fed a 10 ppm selenium diet, as selenomethionine, in this study was not different from eggs laid by herons fed an unsupplemented diet (0.1 ppm selenium). Organ weights, hemoglobin concentrations, hematocrits, eggshell thickness, and shell thickness did not differ between controls and herons receiving 10 ppm selenium. Developmental malformations commonly associated with selenium exposure in other birds were not observed in heron embryos or hatchlings in the 10 ppm group. However, three-day-old hatchlings from herons fed 10 ppm selenium had shorter radius-ulna and femur lengths and higher liver malondialdehyde concentrations than controls. Selenium residues in heron eggs were lower than those reported in mallards fed the same amount of selenium. Results of this study suggest that herons are less sensitive to the toxic effects of selenium than mallards. Other hypotheses are also considered to explain the different responses of the two species. |
| Fish Aid — The Lake Mead Fertilization Project | Richard Axler; Larry Paulson; Peter Vaux; Patrick Sollberger; Donald H. Baepler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 125 - 135 | Fish Aid — The Lake Mead Fertilization Project | Sport fishing at Lake Mead in Nevada and Arizona is a resource valued at nearly $100 million per year to southern Nevada. During the past two decades, salmonids, mostly trout, have disappeared entirely, the largemouth bass catch has drastically declined despite greater fishing pressure, and the condition factors for striped bass have steadily deteriorated. It appears that a major reduction in phosphorus loading caused by the upstream impoundment of the Colorado River to form Lake Powell in 1963 and advanced wastewater treatment removal of phosphorus from domestic wastewater inflows in 1981 are the principal factors responsible for decreased production at all levels of the food chain. The Lake Mead Fertilization Project is an attempt to reverse these declining fisheries. The first large-scale test of fertilization occurred on May 30, 1987. More than 300 boats and 1,000 volunteers helped spread 20,000 gallons (75.7 m3) of liquid ammonium polyphosphate over 19,000 acres (7700 ha) of lake surface. Highlights of the history of the project and initial results, which indicate that the test was extremely successful, are discussed. |
| Determining the Statistical Sensitivity of the Water Quality Monitoring Program in the Taylor – Nubbin Slough, Florida Project | Jean Spooner; Sarah L. Brichford; Richard P. Maas; Michael D. Smolen; David A. Dickey; Gary Ritter; Eric Flaig | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 113 - 124 | Determining the Statistical Sensitivity of the Water Quality Monitoring Program in the Taylor - Nubbin Slough, Florida Project | Reducing agricultural nonpoint source (NPS) pollution by implementing best management practices (BMPs) throughout entire watersheds' is being studied in 20 Rural Clean Water Program (RCWP) projects throughout the United States. The Taylor Creek - Nubbin Slough RCWP Project area is located directly north of Lake Okeechobee in southern Florida. The watershed covers 110,000 acres of which 63,109 were identified as critical agricultural sources of phosphorus entering Lake Okeechobee. These sources were primarily improved pastures and dairies. The project has an extensive pre-BMP water quality data base for statistical comparison with post-BMP data. In addition, most of the BMP implementation occurred in 1985, 1986, and 1987, allowing for four to five years post-BMP water quality monitoring before the end of the project. Therefore, this project should be able to document land treatment effects on water quality. Water quality monitoring data from in-stream sampling was analyzed to determine the magnitude of measured concentration change (minimum detectable change, MDC) in total phosphorus (TP) and or-thophosphate-phosphorus (OP) required to indicate that the change is real. High variability in the hydrologic system contributed to a high MDC. The impact of adjustments for precipitation, seasonality, upstream concentrations, and groundwater levels on reducing the MDC were investigated. The MDC for total phosphorus ranges from 10 to 59 percent over nine years of monitoring after adjustments for available covariates. MDC was found to be a function of subwatershed size and variability in covariates such as antecedent precipitation, groundwater levels, season, and upstream concentrations. The RCWP land treatment in the watershed emphasizes stream protection, animal waste management, vegetative cover, and grazing land protection. A significant decreasing trend for total phosphorus in three subwatersheds and at the outflow from the project area was found. These trends appear to be related to RCWP land treatment and to dairy closures. |
| Distribution and Transport of Mercury into Jordan Lake, North Carolina | Kevin G. Robinson; Mark S. Shuman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 147 - 154 | Distribution and Transport of Mercury into Jordan Lake, North Carolina | Jordan Lake, located in central North Carolina, is currently under consideration as a source of drinking water for communities in the surrounding area. A number of streams that discharge into the lake receive considerable industrial and municipal wastewater effluent, of which the toxic metal mercury is of particular concern. Stream samples, coinciding with low and high flow events, were collected and analyzed for dissolved and particulate total mercury. Mercury loading was estimated from flow-weighted mean concentrations and mean stream flow data. Results indicated that total dissolved mercury concentrations decreased with increasing flow, dilution effects, and that total particulate mercury concentrations decreased sharply with increasing suspended loads. This decrease was attributed to changes in particle size distribution. In addition, variability in particulate mercury concentration decreased dramatically with increased flow. Total mercury concentrations ranged from 54 ng/L to 195 ng/L (mean = 127 ng/L, n = 168). Approximately one-half of the 136 kg/yr of mercury transported to the lake was associated with the suspended fraction, 52 to 65 percent during high flow and 43 to 57 percent during low flow conditions. Greater than 90 percent of the mercury loading into Jordan Lake occurs during high flow events because of heavy suspended solids loading. |
| The New York Citizens' Statewide Lake Assessment Program | Scott A. Kishbaugh | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 2 | 1988 | 137 - 145 | The New York Citizens' Statewide Lake Assessment Program | The New York Citizens' Statewide Lake Assessment Program is a cooperative effort between the New York State Department of Environmental Conservation (NYSDEC) and the New York Federation of Lake Associations, Inc. In this program citizen volunteers from lake associations throughout the state monitor the water quality in their lakes. Water samples and lake observations are collected at a single designated site and depth, as outlined in a sampling protocol manual and in training sessions conducted by professional staff. Samples are taken on a weekly basis for 15 weeks from June through September. Water samples are collected from the deepest water column in each lake, and analyzed by the New York State Department of Health in Albany. Results from this study will be used to construct a data base from which the Department of Environmental Conservation hopes to devise and implement a management strategy for each lake. |
| Planktonic Indicators of Lake Acidification in the Adirondack Mountain Region of New York State | Clifford A. Siegfried | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 115 - 121 | Planktonic Indicators of Lake Acidification in the Adirondack Mountain Region of New York State | Recent studies of plankton community structure in Adirondack lakes are summarized in relation to lake acidity status. Species richness of phytoplankton, planktonic rotifers, and crustacean zooplankton declines with decreasing pH. Highly acidic waters (pH < 5.0) average fewer than 20 phytoplankton and fewer than 12 zooplankton species in midsummer collections. More circumneutral lakes (pH > 6.0) average more than 33 phytoplankton and 20 zooplankton species. This decline in species number represents a simplification of plankton community structure rather than the invasion of new species. Very few Adirondack plankton species can be considered alkalibiontic or acidobiontic. The dominant species of acidic lakes are also generally important in non-acidic lakes of the region. Thus, presence or absence is generally not a very good indicator of lake acidity. However, shifts in the relative abundance/biomass of some species or species groups appear to be consistent with changes in pH. The relative biomass of acidobiontic diatoms and mallomonads is reported to provide a good index of acidity status. The relative biomass of the rotifer, Keratella taurocephalaprovides a consistent indicator of acidity. Among the crustacean zooplankton it appears that the combined relative biomass of Diaptomus minutusand Bosmina longirostrismay be a useful indicator of water quality changes associated with acidification. |
| Long-term Monitoring of Fish Communities in Acid Sensitive Lakes in Ontario | J. M. Gunn; L. E. MacKay; L. I. Deacon; T. J. Stewart; F. J. Hicks; B. P. Munroe; G. L. Beggs | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 123 - 134 | Long-term Monitoring of Fish Communities in Acid Sensitive Lakes in Ontario | A monitoring program began in 1982 to establish baseline data from which to assess long-term effects of acid deposition on fish communities in 20 low alkalinity (0-2.6 mg/L) lakes in south-central Ontario. The study lakes were all clear (dissolved organic carbon < 4 mg/L and dilute conductivity > 35 μS/cm), but differed in size (11-607 ha) and fish community composition (2 to 18 species). Monitoring included assessment of fish species presence, abundance, age composition, growth, recruitment, and angler harvest. Field toxicity tests were used to test the direct toxicity of lake or runoff water to sensitive life stages of various indigenous fish species. A description of the sampling procedures and some current findings from this ongoing study are presented. |
| What is Left for Researchers in Liming? A Critical Review of State-of-the Art Acidification Mitigation | Harald U. Sverdrup; Per G. Warfvinge | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 87 - 97 | What is Left for Researchers in Liming? A Critical Review of State-of-the Art Acidification Mitigation | A critical review of state-of-the-art methods of acidification mitigation in North America, Norway, and Sweden reveals a common base of knowledge among the programs; however, differences in implementation philosophy are apparent. The use of mathematical models, calculation routines, and systematic analyses in water and watershed acidification mitigation is critically studied and the impacts of the inherent assumptions and simplifications are discussed. Several areas where present methods do meet the defined goals of the operational liming programs are described. Other areas where more accurate knowledge would be desirable are also identified, including the interaction of aluminum chemistry, soil chemistry, and liming; the effects of hydrological changes; and the conditions for dissolution of neutralization agents under actual field application. |
| Watershed Liming | Per Warfvinge; Harald Sverdrup | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 99 - 106 | Watershed Liming | Watershed liming is one method used to increase the alkalinity and reduce the aluminum content of surface waters. To increase the understanding of the processes involved in soil liming and develop a tool for planning and evaluating terrestrial liming operations, a mathematical model was developed. The model includes key soil processes such as limestone dissolution, cation exchange, and the leaching and accumulation of dissolved components. The model's ability to describe short-term and long-term improvement of watershed liming upon stream water chemistry is demonstrated by comparing model calculations with data from Swedish full-scale experiments. Watershed liming as a management method is discussed in relation to watershed characteristics. The influence of temporal, hydrological, and hydrochemical variations, as well as liming design parameters is demonstrated as well. The model is used to assess the applicability of watershed liming as a tool for neutralizing acid lakes. Simulations of the responses of different lakes suggest that watershed liming may provide interesting advantages when compared to traditional lake liming methods, although a higher annual treatment cost must be expected. |
| Effects of Calcite Treatment on Primary Producers in Acidified Adirondack Lakes — Response of Macrophyte Communities | Paul A. Bukaveckas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 107 - 113 | Effects of Calcite Treatment on Primary Producers in Acidified Adirondack Lakes — Response of Macrophyte Communities | The effects of limestone addition on two Clearwater, acidic lakes in the Adirondack mountain region of New York state were studied by investigators participating in the Lake Acidification Mitigation Project (LAMP). Biomass and percent cover of the dominant macrophyte species (Utricularia purpurea) were recorded during the period of maximal standing crop for one year prior to and three years following calcite addition. The progressive dieback of U. purpureafollowing lake treatment suggests that this species does not tolerate changes in water quality associated with calcite addition. Calcite treatment may affect macrophyte growth by reducing the availability of dissolved carbon dioxide (CO2). For species that rely exclusively on carbon dioxide as a carbon source for photosynthesis, calcite addition may reduce growth rates, since carbon dioxide is depleted during calcite dissolution. Reduced light penetration during the post-treatment period may also contribute to the decline of the U. purpureapopulation. |
| Efficacy of Rotovation in Controlling Eurasian Watermilfoil in the Pend Oreille River, Washington | Maribeth V. Gibbons; Harry L. Gibbons Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 153 - 160 | Efficacy of Rotovation in Controlling Eurasian Watermilfoil in the Pend Oreille River, Washington | Full-scale mechanical rotovation of Eurasian watermilfoil (Myriophyllum spicatum) beds was conducted at selected sites along the Pend Oreille River in eastern Washington during the fall of 1986. Fifteen hectares (36 acres) of milfoil-infested river sediments were mechanically tilled to dislodge rootcrowns from the substrate. Treatment was performed by a prototype float-mounted rotovator equipped with a 2.5 m (8-foot) wide pivoting rototiller head. Treatment effectiveness was quantitatively assessed by comparing changes in stem density of M. spicatumin the plot before and after rotovation. Milfoil stem density reductions of 63 to 90 percent were observed in the rotovated area immediately after treatment. Carryover stem density reduction of 25 to 70 percent measured in the growth season following the 1986 rotovation treatment suggested that control of M. spicatumgrowth for greater than the season of treatment is possible. Efficiency of milfoil root removal by rotovation was dependent on substrate type, operator skill, and adequately powered machinery. Rotovation appears to be a most promising control technology capable of achieving high rates of milfoil root removal and maintaining long-term reductions in plant growth. |
| Case Study: The Lake Springfield Sediment Removal Project | James H. Buckler; Thomas M. Skelly; Michael J. Luepke; Gary A. Wilken | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 143 - 152 | Case Study: The Lake Springfield Sediment Removal Project | Lake Springfield is a 1,635 hectare reservoir located in central Illinois. The lake is important to the City of Springfield since it serves as a cooling lake for two municipal coal-fired power plants and is the chief water supply source for the area. Accumulation of 13 million cubic yards of sediment in the upper reaches of the lake threatened its adequacy to meet the City's future water supply requirements. Moreover, effects of agricultural runoff into the lake reduced recreational opportunities and contaminated several species of fish to the extent that the Illinois Environmental Protection Agency (IEPA) issued an advisory limiting their consumption. As a result, a three-phase, $9 million lake rehabilitation project was initiated consisting of shoreline stabilization, watershed soil conservation, and sediment removal. The major portion of the project required hydraulic removal of nearly 2.7 million cubic yards of sediment from the upper reaches of the lake. Unexpectedly, the possibly toxic nature of the dredged silt because of the presence of dieldrin and chlordane in the lake sediment, complicated approval of disposal site permits. Also, opponents claimed that the project was subject to Resource Conservation and Recovery Act (RCRA) regulation. It was demonstrated that concentrations of dieldrin and chlordane in the sediment were near detection limits and substantially below ambient levels found in farmland soils. The first phase of the project included development of a 79-hectare sediment retention site for removal of 1.2 million cubic yards of silt. Project costs for the first phase were $4.1 million, or $3.01 per cubic yard of dredged sediment. Early information gained from the project reinforced the need for extensive baseline data for material characterization to avoid project delays or unnecessary costs for similar projects. |
| Sediment–Water Interactions in Farm Dugouts Previously Treated with Copper Sulfate | E. E. Prepas; T. P. Murphy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 161 - 168 | Sediment-Water Interactions in Farm Dugouts Previously Treated with Copper Sulfate | In 1987 10 drinking water dugouts or manmade ponds in northwestern Alberta were studied to evaluate how much copper (Cu) had accumulated in the bottom sediments and whether this sediment copper recycled back into the overlying water. Six dugouts had been treated with varying dosages of copper sulfate (up to 950 μg/L Cu/yr) annually until 1986, and four dugouts had not been treated recently with copper sulfate. None were treated with copper sulfate in 1987. Copper concentrations in the sediments of all 10 dugouts reflected the treatments given: copper levels in the surface sediments of the treated dugouts reached 2 mg/g copper (dry weight), but were less than 40 μg/g copper in the untreated dugouts. Total dissolved copper concentrations in the limnetic zone of the six dugouts treated previously with copper sulfate fluctuated (up to 99 μg/L copper) during the summer; whereas they remained low in the untreated dugouts (< 10 μg/L copper). Large increases in limnetic copper concentrations were associated with periods when water overlying the bottom sediments was low in dissolved oxygen (<2mg/L). In contrast to observations in some other systems, evidence is provided that copper accumulated in bottom sediments can recycle into the open water throughout the summer. |
| Changes in the Morphometry of Las Vegas Wash and the Impact on Water Quality | Richard A. Roline; James J. Sartoris | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 135 - 142 | Changes in the Morphometry of Las Vegas Wash and the Impact on Water Quality | Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mead. Over 80 percent of the normal discharge of approximately 3.4 m3/s (120 ft3/s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly reduced the wetland area within Las Vegas Wash. The reduction in wetland area shortened water travel time in the wash and affected water quality. The primary impacts on the water entering Lake Mead have been an increase in temperature, a decrease in dissolved oxygen concentration, and an increase in ammonia levels. Other physical-chemical parameters and changes in nutrient transformations are also discussed. |
| Direct Measurement of Groundwater Flow and Quality as a Lake Management Tool | David F. Mitchell; Kenneth J. Wagner; Clyde Asbury | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 169 - 178 | Direct Measurement of Groundwater Flow and Quality as a Lake Management Tool | The flow of groundwater into and out of lakes can have a substantial impact on their hydrologic and nutrient budgets. The use of a simple device (a manometer) sensitive to differences in water pressure allows delineation of potential zones of contribution (inflow) and recharge (outflow). Application of simple seepage meters allows quantification of groundwater flows. Pore water extracted from lake sediments in zones of contribution can be chemically analyzed to allow quantification of nutrient loadings to the lake via the groundwater. In 1987, these devices were used to measure groundwater flow to 11 Massachusetts lakes. Groundwater inflow accounted for between 1 to 57 percent of the total lake inflows. Inflows were greatest in kettlehole lakes and least in stream impoundments. Seepage meter measurements were significantly affected by season and local shoreline topography. Distance from shoreline and sediment nature were also factors. A recommended approach for using these devices is considered. Direct measurement of groundwater flow and quality is essential to the proper characterization of lakes without major tributaries and to the evaluation of available management techniques. |
| Agricultural Nonpoint Source Control: Experiences from the Rural Clean Water Program | Richard P. Maas; Sarah L. Brichford; Michael P. Smolen; Jean Spooner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 51 - 56 | Agricultural Nonpoint Source Control: Experiences from the Rural Clean Water Program | In response to the growing awareness that agricultural nonpoint source (NPS) pollution can only be effectively addressed on a watershed/water resource level, the Rural Clean Water Program (RCWP) has become a major source of practical information on how to conduct a successful NPS control project. This paper highlights “lessons learned†on NPS control projects in their planning or early implementation stages. Repeated contact with land owners along with economic incentives are vital for high rates of former participation. Accurate information on Best Management Practices (BMPs) is best provided by agricultural agency personnel. Targeting critical areas is fundamental to cost-effective NPS control, and criteria for defining these areas should be readily identifiable and specific. Offering valuable services to farmers in return for fertilizer management promotes cooperation. Although the RCWP is not designed to establish direct cause/effect relationships for BMPs (i.e., water quality improvement) it will continue to provide information on cost-effective means for monitoring and implementing NPS controls. |
| Nonpoint Source Pollution Impacts of Agricultural Land Use | A. N. Sharpley; S. J. Smith; J. R. Williams | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 41 - 49 | Nonpoint Source Pollution Impacts of Agricultural Land Use | The amounts of soluble and particulate phosphorus (P) and nitrogen (N) transported in runoff from agricultural land were predicted using relationships describing the physical and chemical processes involved in their transport. These values were compared with amounts measured in runoff from nine unfertilized grassed, six fertilized wheat, and five fertilized mixed crop watersheds in Oklahoma and Texas over a 10-year period. An estimate of the bioavailability of sediment-bound phosphorus (0.1 Msodium hydroxide extractable) was also included in the analysis. Measured and predicted soluble phosphorus (R2=0.97), particulate phosphorus (R2=0.93), bioavailable phosphorus (R2=0.98), and total nitrogen concentrations (R2=0.93) in runoff from all 20 watersheds in 801 events were not significantly different (5 percent level), with an average standard error of 11,13,13, and 16 percent, respectively, for the predicted value. This was the case for a wide range in measured concentrations (8-9132, 10-88076, and 4-3596 μg/L, and 0.3-254.0 mg/L for soluble, particulate, and bioavailable phosphorus, and total nitrogen, respectively). Predictive relationships may be improved, particularly for low flow events of low soil loss (<50 kg/ha/yr), by making the relationship constants a function of soil loss or land use factors affecting soil loss. Land-use impacts on nonpoint source transport of phosphorus and nitrogen were evident, with losses increasing in the order: grass, mixed-crop, and wheat. The average loss of phosphorus and nitrogen (1.3 and 5.1 kg/ha/yr, respectively) was not of major importance from an agronomic standpoint, when compared to fertilizer input (8 kg phosphorus and 41 kgN/ha/yr). However, soluble phosphorus concentrations were consistently above values associated with accelerated eutrophication (10 μg/L), even in unfertilized cases. |
| An Educational Program for Farmers on Preventing Lake Contamination from Agricultural Pesticides | Richard P. Maas; Len C. Stanley | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 57 - 61 | An Educational Program for Farmers on Preventing Lake Contamination from Agricultural Pesticides | Pesticides continue to be one of the major causes of fishkills in the United States, and can contaminate surface and ground water supplies that provide drinking water for animal and human populations. During the past 10 years a wealth of research data has been amassed on the aquatic transport properties of various pesticides and pesticide classes. However, there has been a serious dearth of practical information for agricultural pesticide applicators to use to avoid surface and groundwater contamination. This paper describes the components of a successful preventive program for pesticide management that integrates production agriculture and water quality concerns. This educational program has been extensively reviewed by county agricultural agents and soil and water conservation field personnel in North Carolina and is now increasingly being distributed nationally. |
| Balancing Competing Uses for Water Resources — A Griffy Lake Example | William W. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 73 - 80 | Balancing Competing Uses for Water Resources — A Griffy Lake Example | The relative scarcity of recreational water resources in southern Indiana places great demands on existing lakes and reservoirs, often to the detriment of the resource. Such is the case with Griffy Lake, a small (44 ha) water supply reservoir on the northern edge of Bloomington. Griffy Lake's setting and its heavily forested, steeply sloping, and largely undeveloped watershed offers a multitude of recreational opportunities. In recent years, heavy public demand, inappropriate recreational uses, and the lack of a written management plan or policy have resulted in deterioration of the lake and its watershed. Using environmental and sociological survey techniques, the present study developed a matrix approach to assist policymakers in evaluating environmental impacts, recreational demand, and compatibility of various recreational uses. The matrix was then used to develop a long-range use and management plan consistent with the long-range planning goals, which balanced recreational, water supply, and natural uses of the area. |
| Measuring Physical and Economic Impacts of Controlling Water Pollution in a Watershed | Parveen Setia; Richard Magleby | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 63 - 71 | Measuring Physical and Economic Impacts of Controlling Water Pollution in a Watershed | This paper discusses the application of an analytical framework using physical and economic models to an Illinois watershed. The results show the cost and effectiveness of the Rural Clean Water Program (RCWP) as implemented in the watershed, compared with several implementation alternatives to reduce nutrient and sediment loading to a local lake used for water supply and recreation. The cost effectiveness of the program in the watershed could have been increased by using program expenditures to achieve more widespread adoption of conservation tillage and certain crop rotation(s) instead of implementing structural measures. Application of the modeling approach to pre-project analysis could have helped rank areas of the watershed for treatment and provide other insights for improving the design and efficiency of the project. |
| Developing Phosphorus Criteria for Minnesota Lakes | Steven A. Heiskary; William W. Walker Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 1 - 9 | Developing Phosphorus Criteria for Minnesota Lakes | The development of practical and successful lake management strategies hinges upon setting realistic goals. Typically, management efforts have focused on the evaluation of watershed nutrient loadings and prediction of lake or reservoir eutrophication responses, expressed in terms of average epilimnetic phosphorus, chlorophyll a, and transparency. This paper describes a methodology for expressing lake conditions and model predictions in terms that are more meaningful to local resource managers and lake users because they relate more directly to perceived aesthetic qualities. Lake conditions are expressed in terms of the frequency or risk of “nuisance†algal levels, based upon extreme values of chlorophyll a(“bloomsâ€), reduced transparency, and user-perceived impairment. Relationships between lake phosphorus concentration and nuisance frequencies of chlorophyll a(e.g., > 10, 20, 30, 60 ppb) and Secchi depth (e.g., < 2,1, .5 meter) are developed by cross-tabulating lake monitoring data. A questionnaire is employed to collect data for relating lake measurements (phosphorus, chlorophyll a, transparency) to subjective classifications or nuisance ratings based upon physical appearance (“crystal clear†to “severe scumsâ€) and recreational suitability (“no problems†to “no swimmingâ€). Using this approach, critical phosphorus levels corresponding to the onset of detectable nuisance frequencies can be estimated. With the nuisance ratings calibrated to user perceptions, these relationships provide a rational basis for setting phosphorus criteria or management goals related to aesthetic qualities. |
| Wisconsin's Self-Help Lake Monitoring Program: A Review of the First Year — 1986 | Carolyn Rumery; James G. Vennie | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 81 - 86 | Wisconsin's Self-Help Lake Monitoring Program: A Review of the First Year — 1986 | The year 1986 marked the first year of the Wisconsin Department of Natural Resources' (WDNR) “Self-Help Lake Monitoring Program.†More than 150 volunteers collected Secchi disk and lake level data on 129 lakes and lake basins throughout the state. The program served both as an educational and data collection function and continues to be a cornerstone of the state's new Lake Management Program. The Self-Help Monitoring Program's success is attributed to four aspects of the program; (1) direct personal contact between volunteers and a WDNR water quality specialist in a training situation; (2) frequent communication between WDNR and volunteers via bimonthly newsletters, individual reports, and the weekly data reporting cards WDNR received from the volunteers; (3) sense of ownership the volunteers felt toward the program; and (4) newspaper articles published in local papers notifying the public that a volunteer was collecting data on a local lake and that a report was available from WDNR. More than 100 requests for reprints of these reports were received. |
| Water Quality Gradients in the Santee-Cooper Lakes, South Carolina | Jeannie R. Pickett; Richard M. Harvey | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 11 - 20 | Water Quality Gradients in the Santee-Cooper Lakes, South Carolina | Spatial and temporal variations in chemical and biological conditions were investigated in the Santee-Cooper Lakes (Marion and Moultrie) of South Carolina. Results from seven intensive surveys of 90 sampling stations, conducted during 1985 and 1986, document the establishment of significant longitudinal gradients in Lake Marion, and minimal gradient development in Lake Moultrie. Differences in reservoir morphometry and hydrodynamics are apparently responsible for this difference between lakes. Pronounced longitudinal gradients in Secchi transparency and in concentrations of total phosphorus, nitrate-nitrite nitrogen, chlorophyll aand pH were observed in Lake Marion, with significant variations for most variables between cove and open-water stations. Cluster analysis classified the stations into “segments†representative of distinct water quality conditions on the basis of light penetration, chlorophyll aand total nutrient concentrations. The number of “segments†identified provided an estimate of the number and type of sampling stations required in a routine monitoring program to adequately characterize the system. The general segmentation is analogous to the circulation patterns observed within these lakes by Patterson and Harvey (1986a, b). |
| Chemistry of Maine's High Elevation Lakes: Results from the HELM Project | Jeffrey S. Kahl; Matthew Scott | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 33 - 39 | Chemistry of Maine's High Elevation Lakes: Results from the HELM Project | The Maine High Elevation Lake Monitoring (HELM) project was designed to complement the 1984 Environmental Protection Agency Eastern Lake Survey (ELS) in Maine by sampling high elevation lakes not included in the statistical population of the ELS. In 1986, all 91 Maine lakes ≥600 meter (m) elevation, ≥0.4 ha, and ≥ 1 m deep were sampled. Half of these are smaller than 4 ha, the minimum for ELS lakes; only four of the ELS lakes were above 600 m elevation. Although the majority of lakes in both populations are circum-neutral, the mean 1984 ELS population estimate for pH was 6.90, but only 5.70 for 1986 HELM lakes. The 1984 ELS estimates for mean acid neutralizing capacity (ANC) and sulfate (SO4) were 205 and 77 μeq/L, respectively, whereas the HELM lakes had mean ANC and sulfate of 76 and 85. The HELM lakes are more dilute, less well buffered, and probably more vulnerable to acidic precipitation than Maine lakes in general. In 1986, six HELM lakes had pH less than 5, and 12 had ANC less than 0. Calculations indicate that as many as one-quarter of the HELM lakes are “acidified,†having lost ANC relative to their normal state as a result of acidic precipitation and, to a lesser extent, of organic acidity. |
| Regional Geology and the Chemical and Trophic State Characteristics of Florida Lakes | Daniel E. Canfield Jr.; Mark V. Hoyer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 4 | 1 | 1988 | 21 - 31 | Regional Geology and the Chemical and Trophic State Characteristics of Florida Lakes | A limnological survey of 165 Florida lakes was conducted between September 1979 and August 1980 to determine their chemical and trophic state characteristics. A wide range of limnological conditions was documented. Average lake pH values ranged from 4.1 to 9.2 and average total alkalinity concentrations ranged from 0 to 204 mg/L as calcium carbonate (CaCO3). Average specific conductance values ranged from 11 to over 5600 μS/cm at 25° C. Mean total nitrogen concentrations ranged from 0.063 to 4.6 mg/L and mean total phosphorus concentrations ranged from 3 to 834 mg/m3. Although lake trophic states ranged from oligotrophic to hypereutrophic, Florida lakes as a group can be characterized as productive, softwater lakes. Over 75 percent of the sampled lakes had total alkalinity concentrations below 40 mg/L as calcium carbonate and total hardness concentrations below 75 mg/L as calcium carbonate. Most of the sampled lakes were either mesotrophic (52 percent) or eutrophic (35 percent) because total phosphorus levels exceeded 10 mg/m3 in over 75 percent of the lakes. The mineral composition of the lakes seems to be strongly related to Florida's geologic and physiographic development. |
| CHEMICAL AND BIOLOGICAL STATUS OF LAKES AND STREAMS IN THE UPPER MIDWEST: ASSESSMENT OF ACIDIC DEPOSITION EFFECTS | James G. Wiener; Joseph M. Eilers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 365 - 378 | CHEMICAL AND BIOLOGICAL STATUS OF LAKES AND STREAMS IN THE UPPER MIDWEST: ASSESSMENT OF ACIDIC DEPOSITION EFFECTS | Many lakes in three areas in the Upper Midwest - northeastern Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan - have low acid neutralizing capacity (ANC) and may be susceptible to change by acidic deposition. Northcentral Wisconsin and the Upper Peninsula of Michigan together contain about 150-300 acidic lakes (ANC ≤ 0), whereas none have been found in Minnesota. These acidic lakes are precipitation-dominated, Clearwater seepage lakes having small surface area, shallow depth, and low concentrations of dissolved organic carbon. The spatial distribution of these acidic lakes parallels a west to east gradient of increasing sulfate and hydrogen ion deposition. Several of these acidic lakes exhibit chemical characteristics and biological changes consistent with those observed elsewhere in waters reported to be acidified by acidic deposition. However, an hypothesis of recent lake acidification is not supported by analyses of either historical chemical data or diatom remains in lake sediments, and natural sources of acidity and alternative ecological processes have not been conclusively eliminated as causative factors. Streams in this three-state region have high ANC and appear to be insensitive to acidic deposition. The species richness and composition of lacustrine fish communities in the region are partly related to pH and associated chemical factors. Sport fishes considered acid-sensitive and of primary concern with regard to acidification include walleye, smallmouth bass, and black crappie. The fishery in at least one lake, Morgan Lake in Wisconsin (pH 4.6), may have declined because of acidification. Given the general lack of quantitative fishery data for acidic Wisconsin and Michigan lakes, however, more general conclusions concerning impacts or the absence of impacts of acidification on the region's fishery resources are not possible. |
| RAINFALL AND WATER QUALITY IN THE SOUTHERN PLAINS | A. N. Sharpley; S. J. Smith; R. G. Menzel; W. A. Berg; O. R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 379 - 384 | RAINFALL AND WATER QUALITY IN THE SOUTHERN PLAINS | The chemical composition of rainfall, agricultural runoff, groundwater, and pond water at several rural Oklahoma and north Texas locations was determined over a number of years (1972-1985). The inputs of acid, P, Cl, and cations in rainfall are not of major agronomic importance, although inputs of N (as NO3-N and NH4-N) and S (as SO4) in rainfall can contribute a significant proportion of the uptake of these elements by grasses or crops. The mean annual pH of rainfall was consistently greater than that of pure rainfall (5.6) averaging 6.5, while the average pH of two farm ponds (7.8) was even greater than that of rainfall. If a decrease in the pH of rainfall in the Southern Plains should occur in the future, the impact of the acidity on surface water will be reduced to a certain degree by the buffering capacity of the area soils. Appreciably more acid was added annually to the agricultural soils of the area via fertilizer P and N than in rainfall. Under present conditions it would take up to 1,500 years rainfall to add as much acid as added by fertilizer in one year. Even with a dramatic decrease in rainfall pH to 4.0, this period would be 10 years. Thus, rainfall acidity presents no immediate threat to agricultural soils, groundwater, or lakes in Oklahoma and north Texas under continuing management practices, although periodic monitoring is recommended due to an increasing number of coal-fired power stations located in this area. |
| APPLICATION OF ILWAS TO ADIRONDACK LAKES | Carl L. Schofield; Charles T. Driscoll | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 345 - 355 | APPLICATION OF ILWAS TO ADIRONDACK LAKES | The ILWAS model was used as a framework to evaluate processes regulating the acid base chemistry of diverse lake types in the Adirondack Mountain region of New York State. The lakes selected for study represented both drainage and seepage basins distributed across regional edaphic and climatic gradients. Seventeen of the sites constitute a system of drainage lakes within the North Branch of the Moose River, located in the west-central Adirondacks. Variability in watershed characteristics of sub-basins in this drainage system and a wide range in surface water chemistry (pH 4.2-7.4) facilitated analysis of primary processes regulating surface water acidification. Additionally, the effects of these watershed acidity gradients on fish species distribution was assessed from recent and historical fish collections and by in situ bioassay to evaluate relative species sensitivity to acidity. Considerable variation in processes controlling acid-base chemistry of Adirondack lakes, both within drainage systems and regionally, were found as a result of variability in soil characteristics (primarily soil depth and mineralogy). hydrologic flowpaths, and reduction processes (both in-lake and watershed) controlling sulfate and nitrate concentrations. Soil characteristics and hydrologic flow paths largely determined base cation supply rates, whereas both hydrology and reduction processes effectively regulated acid anions supplied principally from atmospheric deposition. Inter-watershed acidity gradients related to these controlling processes and interspecific variation in physiological acid tolerance were found to be important determinants of fish species distribution patterns. Fish species with low acid tolerance (particularly cyprinids) had either disappeared from acidified lakes and streams or were found only in areas exhibiting low acidity. Currently, acid tolerant fish species (e.g., Yellow Perch, Percaflavescens) inadvertently introduced into Adirondack waters predominate in acidified drainage systems. |
| APPLICATION OF THE ILWAS MODEL TO THE NORTHERN GREAT LAKES STATES | Paul J. Garrison; Steve R. Greb; Douglas R. Knauer; Dennis A. Wentz; James T. Krohelski; James G. Bockheim; Steven A. Gherini; Cari W. Chen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 356 - 364 | APPLICATION OF THE ILWAS MODEL TO THE NORTHERN GREAT LAKES STATES | In the northern Great Lakes States, seepage lakes are considered more vulnerable to acidification than drainage lakes. The ILWAS model, which was developed for drainage lakes in the Adirondack Mountain Region of New York, has been revised for use in seepage lake systems. Contrasts were observed between the Wisconsin seepage lakes and the drainage lakes in the Adirondack Region of New York. (1) Atmospheric loading of hydrogen and sulfate ions was 77 and 62 percent respectively, lower in Wisconsin. (2) In contrast to the low alkalinity flow-through lakes in the Adirondacks, there are no observed spring pH depressions associated with snowmelt in Wisconsin seepage lakes. (3) Because of deep glacial deposits (32-190 m) at the Wisconsin sites, a longer contact time between groundwater and weatherable minerals provides a substantial buffering capacity via silicate hydrolysis. (4) Inlake alkalinity production by bacterial sulfate reduction in the sediments of Wisconsin seepage lakes plays a significant role in ameliorating the effects of acid deposition. After the ILWAS model was revised and calibrated for Round and East Eightmile lakes, scenarios were run on two other Wisconsin seepage lakes (Crystal and Vandercook) that have alkalinities of less than 30 μeq/L. These scenarios showed that a 25 percent reduction in sulfur loading would change the chemistry of these lakes slightly. The most important processes controlling the pH and alkalinity of these lakes are groundwater input and sediment sulfate reduction. Using these results, we propose new categories of sensitivities to acidification for seepage lakes in the northern Great Lakes States. Lakes with alkalinities greater than 40 μeq/L would not be considered sensitive to acid deposition. Lakes with alkalinities between 20 and 40 μeq/L would be moderately sensitive, and lakes with alkalinities less than 40 μeq/L would be considered sensitive. |
| OVERVIEW OF APPROACH AND LIMING OF LAKES FOR THE LAKE ACIDIFICATION MITIGATION PROJECT (LAMP) | D. B. Porcella | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 401 - 403 | OVERVIEW OF APPROACH AND LIMING OF LAKES FOR THE LAKE ACIDIFICATION MITIGATION PROJECT (LAMP) | The LAMP research is designed to evaluate chemical and biological response to liming in three different drainage lakes in the Adirondacks. The three lakes vary in size, residence time, chemical composition, and biological community composition, encompassing the range of lakes considered in an operational lake liming program. This ecological experiment provides data for use in evaluating specific questions about liming effects on lake ecosystems; namely, fish and other biotic responses to liming, the effects of liming on acidic impulses during spring runoff, and questions related to metal availability and to modeling of pH and ANC. This paper provides an overview of LAMP, describes the liming of Cranberry Pond and Woods Lake in May 1985, and introduces more detailed papers in this symposium by Drisooll et al., Gloss et al., and DePinto et al. that describe the chemical and biological effects of liming and the ability to predict reacidification. Overall, these initial results of LAMP support the thesis that liming is beneficial to acidic lake ecosystems. |
| THE CHEMICAL RESPONSE OF ACIDIC LAKES TO CALCIUM CARBONATE TREATMENT | Charles T. Driscoll; Gerald F. Fordham; William A. Ayling; Leah M. Oliver | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 404 - 411 | THE CHEMICAL RESPONSE OF ACIDIC LAKES TO CALCIUM CARBONATE TREATMENT | The effects of atmospheric deposition on acid-sensitive watersheds have become increasingly apparent. Lake/watershed systems that cannot completely neutralize strong acid inputs are characterized by low pH values and elevated concentrations of trace metals. Populations of fish and other aquatic biota are endangered by this phenomenon. One approach used to mitigate the effects of surface water acidification is direct application of calcium carbonate (CaCO3). Through the Lake Acidification Mitigation Project (LAMP), we investigated the chemical response of acidic lakes to base treatment. Immediately following base application, there was a marked increase in pH, acid neutralizing capacity (ANC), calcium and dissolved inorganic carbon (DIC) associated with the dissolution of calcium carbonate in the treated lakes. The large increase in pH was attributed to the low dissolved inorganic carbon concentrations in the water column prior to liming and limited pH buffering capacity. During the four week period following base application the intrusion of atmospheric carbon dioxide facilitated additional dissolution of the remaining suspended calcium carbonate. This dissolution was accompanied by a gradual decrease in pH (to below 8) and increases in acid neutralizing capacity, dissolved calcium and dissolved inorganic carbon concentrations within the lakes. Concentrations of trace metals in the upper waters decreased about one order of magnitude due to reduced solubility at circumneutral pH values. The rate of reacidification was directly related to the hydrologic input to the lake. Elevated discharge during the fall coinciding with a completely mixed water column greatly facilitated reacidification. Although discharge was very high during spring snowmelt, ice cover and inverse thermal stratification restricted intrusion of acidic meltwater to the ice-water interface. The rapid rate of reacidification was largely attributed to the shallow depth and short hydraulic retention of these lakes. |
| ACIDIFICATION, VERTEBRATE AND INVERTEBRATE PREDATORS, AND THE STRUCTURE OF ZOOPLANKTON COMMUNITIES IN ADIRONDACK LAKES | Clifford A. Siegfried; J. A. Bloomfield; J. W. Sutherland | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 385 - 393 | ACIDIFICATION, VERTEBRATE AND INVERTEBRATE PREDATORS, AND THE STRUCTURE OF ZOOPLANKTON COMMUNITIES IN ADIRONDACK LAKES | Midsummer zooplankton community structures of 50 Adirondack lakes were evaluated in relation to dominant vertebrate and invertebrate predators and selected limnological parameters. The most important factors structuring zooplankton grazer communities were extracted in a principal components analysis. The interaction of acidity status and vertebrate planktivore abundance explains the variation in lake scores for the first principal component. The second principal component was related to predation, while the third was related to lake trophic status and humic influence. The interaction of water quality and predator abundance structures grazer communities of Adirondack lakes. |
| COMPARISON OF METHODS FOR STREAMSIDE AND IN SITU POTENTIOMETRIC pH MEASUREMENTS IN LOW IONIC STRENGTH STREAM WATERS | Charles M. Knapp; Gerald J. Filbin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 394 - 397 | COMPARISON OF METHODS FOR STREAMSIDE AND IN SITU POTENTIOMETRIC pH MEASUREMENTS IN LOW IONIC STRENGTH STREAM WATERS | Potentiometric pH measurement in low ionic strength stream waters is difficult due to high system variability and low ionic activity. Imprecise measurement may result from equipment response in such waters and solution pH drift caused by gaseous exchange and temperature change. An acceptable method for field pH determination must utilize sensitive equipment and stringent measurement stability criteria to ensure accurate and reliable measurements. Four methods for in situ and streamside pH determination were used to collect data from three low-ionic strength streams. The methods are compared, using analysis of variance and subjective evaluation. |
| INSECTS, MITES, AND PLANT PATHOGENS AS AGENTS OF WATERHYACINTH (EICHHORNIACRASSIPES(MART.) SOLMS) LEAF AND RAMET MORTALITY | Ted D. Center | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 285 - 293 | INSECTS, MITES, AND PLANT PATHOGENS AS AGENTS OF WATERHYACINTH (EICHHORNIACRASSIPES(MART.) SOLMS) LEAF AND RAMET MORTALITY | The effects of insect and mite herbivores and plant pathogens on waterhyacinth leaf and ramet mortality were studied at Canal-M, Palm Beach Co., Florida, from December 1981 to January 1983. Individual ramets were tagged in December 1981 and again in May 1982, then monitored to determine rates of leaf production, proportional amounts of damage by various organisms, and ultimate causes of leaf and ramet mortality. Only the moth Sameodesalbiguttalis(Warren) and the weevils, NeochetinabruchiHustache and N. eichhorniaeWarner, caused reduced leaf longevity. Other organisms were sporadic or restricted to old leaves. About 74 percent of the first group of tagged ramets were killed. S. albiguttaliskilled 31 percent by late April, then ceased to be effective due to changing plant morphology. Neochetinaspp. killed 42 percent, and mortality was relatively constant. Neochetinaspp. killed about 33 percent of the shoots tagged in May. We conclude that S. albiguttalisis effective for control of waterhyacinth in only very restrictive circumstances. The weevil N. eichhorniae, and to a lesser extent N. bruchi. are more effective biocontrol agents. The demise of the waterhyacinth population was predictable from a comparison of leaf production and leaf mortality rates. The relationship between herbivore persistence and the plants' ability to replace damaged tissue mediates the resiliency of waterhyacinth populations. |
| STORMWATER RUNOFF TREATMENT IN A WETLAND FILTER: EFFECTS ON THE WATER QUALITY OF CLEAR LAKE | John M. Barten | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 297 - 305 | STORMWATER RUNOFF TREATMENT IN A WETLAND FILTER: EFFECTS ON THE WATER QUALITY OF CLEAR LAKE | Clear Lake, a 257 ha body of water located in south-central Minnesota, is a heavily utilized recreational lake which has become eutrophic because of the inflow of nutrient-rich runoff water from the adjacent City of Waseca. In 1981, 50 percent of the hydraulic load and 55 percent of the phosphorus load to the lake was diverted into a 21.4 ha marsh. The marsh system reduced the annual phosphorus load to Clear lake by 34 percent (768 kg). In 1986 construction was completed on a second marsh system which will filter urban and agricultural runoff carrying 20 percent of the phosphorus load into Clear Lake. The mean total phosphorus concentration in Clear lake has been reduced 31 percent, from 158 ug/L to 109 ug/L, since the diversion in 1981. The total nitrogen:total phosphorus ratio increased from 10:1 to 18:1 since the diversion began. Neither the Secchi disk depth nor the chlorophyll aconcentration was correlated with the reduced total phosphorus concentration in the lake. The control of internal loading will be necessary to eliminate nuisance algae conditions in Clear Lake. |
| MANAGEMENT OF AQUATIC PLANTS IN MULTI-USE LAKES WITH GRASS CARP (CTENOPHARYNGODONIDELLA) | Andrew J. Leslie Jr.; Jess M. Van Dyke; Rue S. Hestand III; Boyd Z. Thompson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 266 - 276 | MANAGEMENT OF AQUATIC PLANTS IN MULTI-USE LAKES WITH GRASS CARP (CTENOPHARYNGODONIDELLA) | Recent hatchery advances producing sterile triploid grass carp and the relaxing of state and federal restrictions on their distribution are expected to result in widespread use of these fish for aquatic plant management in North America. This large Asian cyprinid is a voracious herbivore and must be used properly to avoid major reductions in desirable aquatic vegetation. Grass carp exhibit strong food preferences and should only be used to manage plants that they prefer. Their use to manage plants that they do not prefer can result in expansion of the target plant and severe reductions in non-target species. Food preferences must be verified regionally. For best results, plant biomass should first be reduced and then grass carp should be stocked at 2 fish per metric ton of remaining vegetation. Grass carp should not be used to control aquatic plants in waterfowl management areas. Because grass carp are very difficult to recapture, overstocking should be avoided. Overstocking grass carp has resulted in near complete elimination of submersed plants and severe reductions in many emersed species for periods greater than 10 years. Use of grass carp can increase turbidity, phytoplankton, and nutrient concentrations in the water column but to a lesser degree than can occur using most aquatic herbicides. Provided that they are not overstocked, triploid grass carp appear compatible for use in fisheries management areas. |
| THE EFFECTS OF GRASS CARP ON WATER QUALITY IN MCNEELY LAKE | G. C. Holdren; James D. Mayfield; Stephen D. Porter | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 277 - 282 | THE EFFECTS OF GRASS CARP ON WATER QUALITY IN MCNEELY LAKE | Grass carp (CtenopharynqodonidellaVal.) were introduced to McNeely Lake in August 1985 in an attempt to control nuisance growths of duckweed on the lake surface. Complete control of duckweed was achieved within nine months of the stocking date. No significant changes in nutrient concentrations, dissolved oxygen levels, or general water quality parameters have been observed. Although phytoplankton standing crop, as estimated by chlorophyll a levels remained unchanged, there appears to have been a shift in algal populations toward smaller species and diatoms. |
| INTERPRETING PATTERNS OF LAKE ALKALINITY IN THE UPPER MIDWEST REGION USA | Glenn E. Griffith; Andrew J. Kinney; James M. Omernik | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 329 - 336 | INTERPRETING PATTERNS OF LAKE ALKALINITY IN THE UPPER MIDWEST REGION USA | Patterns in alkalinity data for lakes and streams in Minnesota, Wisconsin, and Michigan were analyzed and mapped as a first step toward determining the potential sensitivity of surface waters to acidic deposition. The mapping was accomplished by: (1) assembling available alkalinity data on as many surface waters as possible, (2) plotting these data on relatively large-scale maps; and (3) analyzing the patterns of the 14,000 plotted values for spatial associations with other characteristics such as land use, geology, physiography, and hydrology to aid in extrapolation of the data. The level to which each factor influences alkalinity varied within the region. In northeast Minnesota and parts of upper Michigan, bedrock geology can influence surface water alkalinity. In other areas of the region, glacial drift is often very deep, and alkalinity concentrations are influenced by the composition of the drift, the lake hydrologic type, and the amount of groundwater contact. The lakes of lowest alkalinity are found in north-central Wisconsin and the upper peninsula of Michgan and tend to be small in size, comprise a small percent of total surface water area, and often occur in clusters. The mapping project helps meet the urgent need to understand the relative potential sensitivity of surface waters in the Upper Midwest, provides a tool for selecting geographic areas for more detailed studies, and allows more accurate regional assessments of effects of acidic deposition on aquatic resources. |
| ANALYSIS OF REGIONAL PATTERNS IN LAKE WATER QUALITY: USING ECOREGIONS FOR LAKE MANAGEMENT IN MINNESOTA | Steven A. Heiskary; C. Bruce Wilson; David P. Larsen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 337 - 344 | ANALYSIS OF REGIONAL PATTERNS IN LAKE WATER QUALITY: USING ECOREGIONS FOR LAKE MANAGEMENT IN MINNESOTA | Developing lake management strategies that have utility across diverse geographic areas is difficult. For example, with over 12,000 lakes in Minnesota, determining carrying capacities, restoration goals, and lake protective standards cannot be practically made on a lake-by-lake basis. In light of this, the aquatic ecoregion approach was employed to assess regional patterns in watershed characteristics and inlake parameters such as phosphorus concentration, Secchi transparency, and lake mixing pattern. This approach defined seven distinct ecoregions, of which, the following four contain the majority of lakes in Minnesota: Northern Lakes and Forest (NLF), North Central Hardwood Forests (CHF), Western Corn Belt Plains (WCP) and the Northern Glaciated Plains (NGP). Analysis of total phosphorus data from approximately 1,100 lakes by ecoregion resulted in the following median epilimnetic concentrations: NLF - 23 μg P/L, CHF - 50 μg P/L, WCP - 121 μg P/L, and NGP - 176 μg P/L. Lake mixing patterns may be a further basis for organizing the data. These analyses indicate that the aquatic ecoregion approach is a valid method for grouping lake data and identifying spatial patterns of lake characteristics. Further, for Minnesota, this analysis indicates that no single total phosphorus concentration can be used as a basis for setting standards across Minnesota because of its tremendous diversity of lakes and attainable trophic states. Lake management schemes based on the ecoregion analysis presented. |
| OPERATIONAL PROBLEMS WITH A SOIL FILTRATION SYSTEM FOR TREATING STORMWATER | Mark D. Tomasek; George E. Johnson; Patrick J. Mulloy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 306 - 313 | OPERATIONAL PROBLEMS WITH A SOIL FILTRATION SYSTEM FOR TREATING STORMWATER | This paper discusses the use of a soil filtration system constructed to provide additional treatment of urban stormwater following sedimentation. The system was constructed with a Clean Lakes Grant to remove solids and phosphorus from urban stormwater. The system showed severe operational problems following initial construction. During 1985, Minnesota Pollution Control Agency (MPCA) staff determined that proper system operation required corrective measures. A low cost renovation of the system was undertaken during the spring of 1986. Following filter renovation, a monitoring program studied filter efficiency in removing phosphorus and particulate matter. The renovated system operated well the first month, but following a week-long shutdown of the system, aerial hydraulic loading rate and filter efficiency decreased substantially. After three months of operation it was apparent that the renovation was only temporary because of an improper type of peat used in the system. Peat sand filters have been successfully employed for treatment of domestic wastewater and extending their use to treatment of stormwater seems feasible with proper construction. The Agency is considering using peat sand filters for treatment of stormwater in future lake restoration projects. |
| PHOSPHORUS REMOVAL BY URBAN RUNOFF DETENTION BASINS | William W. Walker Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 314 - 326 | PHOSPHORUS REMOVAL BY URBAN RUNOFF DETENTION BASINS | An empirical model previously developed for predicting phosphorus retention in reservoirs is tested against the urban lake/detention pond data set. Detention pond design criteria developed under the EPA's Nationwide Urban Runoff Program (NURP) are ovaluated using the model. For summer precipitation and runoff quality typical of St. Paul, Minnesota, a basin designed according to NURP criteria is estimated to have a long-term-average phosphorus removal efficiency of 47-68 percent. For a given loading regime, phosphorus removal is shown to be more sensitive to pond depth than to surface area. Specific design features for enhancing phosphorus removal (deepening, promoting infiltration, promoting plug flow, and chemical treatment) are discussed. The methodology can be used to evaluate wet detention pond design criteria in other regions, with substitution of appropriate precipitation and runoff quality characteristics. |
| INCORPORATING COST–BENEFIT ANALYSIS OF BEST MANAGEMENT PRACTICES FOR LAKE MANAGEMENT: A NEGOTIATION APPROACH | Patrick J. Mulloy; Peter J. Nowak | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 91 - 98 | INCORPORATING COST-BENEFIT ANALYSIS OF BEST MANAGEMENT PRACTICES FOR LAKE MANAGEMENT: A NEGOTIATION APPROACH | Assessment of costs and benefits of lake restoration techniques aids lake management by identifying the most cost effective approach, determining who benefits from the approach, and identifying who should pay for the approach. Traditional lake restoration techniques rely upon fairly straightforward methods for determining costs of the project and identifying the benefits. However incorporating nonpoint source controls into lake water quality management strategies requires understanding the costs of nonpoint source pollution as well as the potential benefits of different management strategies. Yet cost-benefit analyses of nonpoint source pollution impacts and corrective practices have traditionally focused on a narrow range of onsite costs and benefits to the owner-operator. To become an effective water quality management tool, these analyses must encompass a broader view and become sensitive to how political and social processes will influence the negotiation of economic costs and benefits. This paper reviews existing cost-benefit models and discusses criteria for their use as lake management tools and discusses the implications that a broader negotiation approach can have on lake management decisionmaking. |
| ALUMINUM SULFATE TREATMENT OF A EUTROPHIC RESERVOIR: RATIONALE, APPLICATION METHODS, AND PRELIMINARY RESULTS | Robert H. Kennedy; John W. Barko; William F. James; William D. Taylor; Gordon L. Godshalk | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 85 - 90 | ALUMINUM SULFATE TREATMENT OF A EUTROPHIC RESERVOIR: RATIONALE, APPLICATION METHODS, AND PRELIMINARY RESULTS | Aluminum sulfate was applied to eutrophic Eau Galle Lake to control internal phosphorus recycling from anoxic sediments for a period of five years, and to provide increased user benefits at a reasonable cost. Treatment dose (11.3 g Al/m2) was based on mass balance estimates of summer Internal phosphorus loading rates; no attempt was made to curtail external loading rates. Phosphorus concentrations in bottom waters, internal phosphorus loading rate, and the abundance of blue-green algae were reduced relative to previous years; however, algal biomass remained relatively high. The proliferation of the dinoflagellate Ceratiumhirundinella, a vertical migrator, suggested that these algae may have obtained phosphorus from interflowing river waters having a high nutrient content. |
| EVALUATION OF A PREDICTION METHOD FOR OXYGEN INJECTION REQUIREMENTS IN RICHARD B. RUSSELL LAKE | Stephen P. Schreiner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 76 - 84 | EVALUATION OF A PREDICTION METHOD FOR OXYGEN INJECTION REQUIREMENTS IN RICHARD B. RUSSELL LAKE | To maintain an oxygen concentration of at least 6 mg/L in the discharge, an oxygen injection system was designed for the Corps of Engineers peaking hydropower project on the 10,785 ha Richard B. Russell Lake (Georgia-South Carolina). To aid in the operation of the oxygenation system, a mathematical model was developed to compute the amount of oxygen required to meet the desired discharge standard. Factors considered by the model included the outflow rate, oxygen depletion rates, hypolimnetic volume, oxygen deficit, selective withdrawal patterns and oxygenation efficiency. Oxygen depletion rates and hypolimnetic oxygen deficit were computed from in situ profiles; selective withdrawal patterns were computed based on temperature profiles and hourly project operation records. Results for the 1985 season indicated that the model could be used to provide a rapid and more accurate estimate of oxygen requirements than previously available. When compared with operation of the system based only on maintaining downstream discharge requirements, use of the model could result in a substantial cost savings. |
| THE U.S. ENVIRONMENTAL PROTECTION AGENCY'S CLEAN LAKES PROGRAM: 1975–1985 | A. C. Hall; S. A. Peterson; J. Taggart; G. M. DeGraeve; B. W. Vigon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 117 - 128 | THE U.S. ENVIRONMENTAL PROTECTION AGENCY'S CLEAN LAKES PROGRAM: 1975-1985 | The EPA Clean Lakes Program was initiated in 1975 to protect publicly-owned freshwater lakes under Section 314 of the Clean Water Act. A review of the first decade of the Program by Battelle Memorial Institute highlights the accomplishments of the Clean Lakes Program, the results of federally funded projects and recommendations for the future. From 1975 to 1985, EPA funded 313 Clean Lakes studies and projects totaling $93 million in federal dollars. Forty-seven states and Puerto Rico participated. The majority of funds (87 percent) was awarded to lake restoration projects. The remainder was used for lake classification studies and diagnostic feasibility studies. Public concern about lake eutrophication was the most significant factor in prompting action that resulted in restoration. The Program has improved water quality nationwide; examples of public and economic benefits are cited. In addition, the Clean Lakes Program has contributed to the science of lake restoration through a better public and scientific understanding of lake eutrophication, detailed information on successful restoration measures and the development of new restoration techniques. |
| OXYGEN DEMAND OF LAKES: SEDIMENT AND WATER COLUMN BOD | Timothy K. Cross; Robert C. Summerfelt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 109 - 116 | OXYGEN DEMAND OF LAKES: SEDIMENT AND WATER COLUMN BOD | The total biochemical oxygen demand (TBOD, g O2m-2) of two small, ≤ 5.0 ha, eutrophic lakes in central Iowa was estimated from measurements of the biochemical oxygen demand (BOD) from the top 25 mm of sediments (SBOD) and summation of the BOD values from each 1-meter strata of the water column (WBOD). Standard BOD procedures were used for both sediment and water column biochemical oxygen demand, although a special protocol was developed for the sediments. Continuous recording of the oxygen consumption of selected sediment samples during the five-day BOD procedure revealed a high initial oxygen demand which then declined exponentially over the five-day interval; the oxygen consumption in 20 minutes averaged 26 percent of the mean five-day SBOD value. The sediment and water column biochemical oxygen demand were measured for 28 months in both lakes. WBOD (9 O2m-2) values ranged from 2.0 to 13.1 and mean values were 5.1 and 6.5, respectively, in the two lakes. SBOD (g O2m-2) values ranged from 27.7 to 138.6 and averaged 79.6 and 80.3 in the two lakes. Monthly variation in water column and sediment biochemical oxygen demands were independent. Sediment values were greater than 90 percent (96.5 percent of the total demand in one lake and 94.0 percent in the other lake) of the total biochemical oxygen demand in 9 of 56 monthly samples in both lakes. During the winter ice-covered interval, sediment biochemical oxygen demand and the dissolved oxygen content of the water column were negatively correlated for the two 1-m strata nearest to the bottom. |
| DEVELOPMENT OF TOXIC BLUE-GREEN ALGAL BLOOMS IN BLACK LAKE, KOOTENAI COUNTY, IDAHO | Jacob Kann; C. Michael Falter | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 99 - 108 | DEVELOPMENT OF TOXIC BLUE-GREEN ALGAL BLOOMS IN BLACK LAKE, KOOTENAI COUNTY, IDAHO | Increasing occurrences of blue-green algal blooms in lakes throughout the western United States have been linked to recreational use, sewage inputs, and nonpoint runoff from agricultural and grazing sources. In certain instances these blooms produce toxins that can be lethal to fish, aquatic invertebrates, mammals, and humans. Black Lake in northern Idaho has experienced late summer and fall growths of a toxic alga, Anabaenaflos-aquae. Demonstrated fatal toxicity to cattle and small mammals occurred in 1981, 1982, 1983, and 1985. The eutrophication and subsequent toxic blooms in Black Lake can be related to its large nonpoint nutrient input from the surrounding watershed. The presence or absence of cattle on adjacent meadows may be a major determining factor in bloom formation. Despite a high proportion of sediment (55 percent) exposed to anaerobic conditions during summer stratification, it appears that internal loading alone does not play a significant role in the triggering of a toxic bloom in Black Lake. Development of a toxic A. flos-aquaebloom in Black Lake is dependent on a series of interdependent environmental controls. The most important conditions in Black Lake appear to be high spring nutrient load (compounded by the presence of cattle), high fall water temperature, and stable water column conditions in the fall. The A. flos-aquaestrain present in Black Lake formed surface concentrations and produced anatoxin-a, despite comprising only 1-2 percent of the total algal biovolume in the water column. Anatoxin-a is produced at times other than when massive surface scums are formed, indicating toxic strains are more widespread in occurrence than previously perceived. |
| RESPONSE OF SILVER LAKE TROPHIC STATE TO ARTIFICIAL CIRCULATION | Thomas M. Brosnan; G. Dennis Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 66 - 75 | RESPONSE OF SILVER LAKE TROPHIC STATE TO ARTIFICIAL CIRCULATION | Artificial circulation is a lake management technique which can sometimes improve the quality of eutrophic impoundments. While improvements associated with extension of oxygenated habitats are common, other benefits such as reduction of algal biomass and changes in phytoplankton and zooplankton species composition are less certain. Circulation was implemented from June through October 1982 in eutrophic Silver Lake, Summit County, Ohio. Dissolved oxygen was maintained at the bottom of most stations, with a concomitant increase in zooplankton and benthic macroinvertebrate ranges. Negative results included increases of surface phosphorus, chlorophyll, and algal biomass, a slight decline in transparency, and the continued predominance of blue-green algae at the surface. One station was partially isolated by basin morphometry and functioned as an in-lake control which remained physically, chemically, and biologically stratified. The overall trophic state of the lake as measured by phosphorus, transparency and chlorophyll declined. Reasons for these undesirable results include failure of the system to maintain isothermal conditions, failure to achieve a pH and phytoplankton shift, and mixing of sediments into the water column from placement of the diffuser directly on the lake bottom. |
| CONTROL OF INTERNAL PHOSPHORUS LOADING IN TWO SHALLOW LAKES BY ALUM AND AQUATIC PLANT HARVESTING | David A. Morency; Thomas J. Belnick | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 31 - 37 | CONTROL OF INTERNAL PHOSPHORUS LOADING IN TWO SHALLOW LAKES BY ALUM AND AQUATIC PLANT HARVESTING | Erie and Campbell Lakes are two shallow, nonstratified lakes located in Skagit County, Washington. Both lakes suffered from dense blooms of blue-green algae during late summer. Erie Lake also suffers from occasional fish kills. A Phase I diagnostic study conducted in 1981-82 identified phosphorus as the nutrient controlling algal growth, and internal phosphorus loading via sediment release and aquatic plants was viewed as the most significant controllable sources. The restoration plan recommended aluminum sulfate (alum) to control sediment P release and mechanical harvesting to remove plant phosphorus. Harvesting would also provide recreational benefits and control any increased plant colonization made possible by improved water clarity. Both lakes were treated with liquid alum during Fall 1985, and the harvesting program was implemented in Summer 1986. The 1986 post restoration values indicate a dramatic improvement in the quality of Erie Lake. Mean summer total phosphorus concentrations were reduced from 115 to 26 μgP/L, chlorophyll a concentrations were reduced from 58 to 5 μg/L, while water clarity increased from 1.7 to 2.5 + meters. Improvements in Campbell Lake were significant but not as dramatic as Erie Lake; mean summer total phosphorus concentrations were reduced from 49 to 28 (μgP/L, chlorophyll a concentrations were reduced from 18 to 10 μg/L, but water clarity remained similar to pre-restoration values (1.8 meters). |
| Panelists' Responses | | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 17 - 28 | Panelists' Responses | |
| NUMERICAL STANDARDS FOR MANAGING LAKE AND RESERVOIR WATER QUALITY | Alfred M. Duda; Myron L. Iwanski; Robert J. Johnson; John A. Jaksch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 1 - 16 | NUMERICAL STANDARDS FOR MANAGING LAKE AND RESERVOIR WATER QUALITY | Even as attention to our nation's lake resources has sharpened in the past decade, water quality surveys repeatedly indicate deteriorating lake water quality. Several recent surveys indicate that the percentage of lake and reservoir waters impaired or threatened by pollution is higher than that of streams, rivers, estuaries, or groundwaters. This paper was prepared to stimulate debate on the need for specific numerical standards for managing water quality in lakes and reservoirs, and argues for them. A panel of reviewers representing different interest groups debated the issues presented in this paper at a plenary session at the 1986 Conference of the North American Lake Management Society; comments from the debate and additional opinions follow the paper. The principal authors also worked with contributors from a wide variety of institutions in writing this paper. This brought viewpoints ranging from engineering and agricultural perspectives in the university community to local, state, and federal government organizations. After reviewing the status of water quality in U.S. lakes and reservoirs and discussing innovative, comprehensive approaches for achieving point and nonpoint source pollution reduction, the authors conclude that degradation of our lake resources is a very serious national problem, one that does not appear to be adequately addressed by existing institutions. The paper addresses alternative lake protections approaches - from technology-based point and nonpoint control standards, to lake inflow or in-lake water quality standards and innovative watershed-based practices - the advantages and limitations of using simulation modeling to establish standards, and the importance of biological monitoring in establishing ecologically-based standards. Case studies illustrate the utility and limits of the various approaches. The paper particularly emphasizes a case study of watershed-based, point/nonpoint pollution reduction tradeoffs in Colorado, and a watershed-based, special classification system and non-point source control cost-sharing program for eutrophic reservoirs in North Carolina. The authors suggest possible federal and state approaches for using specific, numerical or ecologically-based standards to restore and protect lake and reservoir water quality. |
| IMPROVEMENT IN MOSES LAKE QUALITY FROM DILUTION AND SEWAGE DIVERSION | Eugene B. Welch; Evan R. Weiher | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 58 - 65 | IMPROVEMENT IN MOSES LAKE QUALITY FROM DILUTION AND SEWAGE DIVERSION | Moses Lake has received dilution water in 9 of 10 years since treatment began in 1977. The average input for those years was 143 ± 79 106m3/yr over 93 days, which represents flushing rates of about 13 percent/day for Parker Horn where the dilution water enters, and 1 percent/day for the whole lake. As a result, lake quality has improved at least 50 percent in terms of chlorophyll aand total phosphorus and by nearly 100 percent in transparency. Pumping diluted lake water from Parker Horn beginning in 1982 and diverting sewage effluent in 1984 markedly improved water quality in a section that received treated effluent and little or no dilution water. Total phosphorus has declined by 90 percent and chlorophyll aby 60 percent, although transparency increased only about 0.2 m because of that section's shallowness. Diluted nitrate concentration in the inflow has been considered the cause for control of algae, but a switch from largely flood to spray irrigation, as well as sewage diversion, has resulted in lower inflow phosphorus concentrations and a gradual change from N to P limitation. Despite favorable improvements in average conditions, however, blooms of blue-green algae still develop in late summer. The largest bloom in the 10 + year study occurred from late August through September 1985, when the lake was well diluted and received no sewage. This is attributed to increased mixing following lower than normal temperature and to a 50 percent increase in internal phosphorus loading. Buoyant blue-green algae rising from the sediment surface are hypothesized to be the transport mechanism. |
| SEDIMENT PHOSPHORUS RELEASE REDUCES THE EFFECT OF THE CHAIN LAKE WATER DIVERSION | Tom Murphy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 48 - 57 | SEDIMENT PHOSPHORUS RELEASE REDUCES THE EFFECT OF THE CHAIN LAKE WATER DIVERSION | In 1968, a 2 km long water diversion was built to flush Chain Lake, British Columbia with nutrient-poor subai-pine water. Unfortunately in some years, blue-green algal blooms (chl a> 100 μg/L) and fish kills still occur. The incomplete success of the diversion is related to the asynchrony of water flow and phosphorus release from the sediments. Internal loading represents about 78 percent of the phosphorus supply to the lake in summer, and water flow is minimal during phosphorus release. Phosphorus in surface sediments is five times more concentrated than in sediments deeper than 80 cm. Diatoms in sediment cores indicate that the lake has been eutrophic for at least 300 years. The accumulation of a diatomaceous ooze in the lake was measured by three methods to be between 0.5 and 1 cm a year. A larger diversion would suppress plankton blooms, but in this shallow lake it would enhance the growth of macro-phytes; sediment dredging may be a more effective in situ treatment. |
| PHOSPHORUS LOADING AND DIVERSION FOR PINE LAKE, WASHINGTON | Gregory J. Pelletier; Eugene B. Welch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 38 - 47 | PHOSPHORUS LOADING AND DIVERSION FOR PINE LAKE, WASHINGTON | Phosphorus external and internal loading to Pine Lake was estimated and potential restoration measures were recommended. External sources contributed approximately 57 percent of the total phosphorus load, and internal sources the remaining 43 percent. External and internal loading together exceeded the critical level expected for a mesotrophic state. About one-third of the external load, or about 20 percent of the total, entered through a channel draining a wetland. Total phosphorus concentration in this source was more than six times that in the lake; nearly 90 percent was soluble reactive phosphorus. This inflow will be diverted to the outflow in 1986. Another one third of the external load represented a “residual†occurring during the wet season. This was attributed to cultural activities, namely leachate from near-shore septic systems, although direct evidence was limited. About 35 percent of the total load entered from-internal sources, largely from littoral sediments and photosynthetically elevated pH during the spring algal bloom. This source of input is particularly important because it enriches the epilimnetic waters when the potential for increased algal growth is great. Wetland diversion and correction of failing near-shore septic systems should result in a lower mesotrophic state and greater than a 60 percent reduction in total phosphorus during the spring bloom period if productivity is reduced sufficiently to prevent elevated pH. The success of restoring Pine Lake depends on whether or not internal loading during the spring bloom is substantially reduced. A “worst-case†improvement is only a 12 percent reduction in total phosphorus during the spring bloom maximum, which assumes no change in the pre-diversion littoral sediment phosphorus release rate. However, diversion alone should result in less productivity, lower pH, and less sediment phosphorus release. |
| HANDLING CUMULATIVE IMPACTS IN NONPOINT SOURCE PROGRAMS | Bart Hague | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 131 - 137 | HANDLING CUMULATIVE IMPACTS IN NONPOINT SOURCE PROGRAMS | Nonpoint Source (NPS) assessment, planning, and control programs to protect lakes top short of addressing the cumulative impacts of incremental development. Taken separately, each lakeside dwelling may appear acceptable; cumulatively such developments accelerate eutrophication. A new development may provide the infrastructure or precedent for additional development, and equity becomes a planning issue. The Clean Water Act touches on cumulative impacts in provisions dealing with antidegradation, load allocations and permits. Certain federal/state laws to protect envirionmentaliy-sensitive areas can also be interpreted to cover cumulative impacts. This paper explores the limits to which federal/state environmental laws and local planning and zoning can be used to handle the cumulative impacts of development on lakes. More use can be made of federal authorities, especially now that the Clean Water Act Amendments direct more attention to nonpoint source control. Comprehensive state and local land use planning and regulation needs to be strengthened. THis paper outlines a planning framework to consider cumulative impacts in planning and land use decisions to respect a lake's finite capacity. Comprehensive planning will develop the data and assumptions about environmental constraints and development activities needed to refine the framework and lend legitimacy; in turn, this framework can strengthen comprehensive planning. |
| THE IMPACT OF SUBMERGED MACROPHYTES ON LARGEMOUTH BASS AND BLUEGILLS | Sandy Engel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 227 - 234 | THE IMPACT OF SUBMERGED MACROPHYTES ON LARGEMOUTH BASS AND BLUEGILLS | Underwater macrophytes can influence fish diet and growth by restricting access inshore. The movements of largemouth bass (Microptemssalmoides) and biuegills (Lepomismacrochirus) were followed in a shallow Wisconsin impoundment nearly one-half covered with potamogetons and other macrophytes. Plant density averaged 130-200 g/m2(dry weight) from May through August during the six-year study. Fish activity was observed from a still boat or by diving. Stomach samples of fishes were obtained on 55 dates by boom shocking. Submerged macrophytes at a density above 90 g/m2functioned as a screen to selectively restrict fish movements. Bass and bluegills under age III were mostly confined to plant beds, where they grazed chironomid larvae and other aquatic insects on the plants and lake bottom. Bluegills shifted to zooplankton and finally plant tissue as summer progressed, while bass turned increasingly to fish as prey. Older bass had difficulty in penetrating the plant beds until openings appeared from plant decay or were created by a mechanical harvester. Slow growth of bass after age II was also reported in other Midwestern lakes with dense vegetation and is attributed to their difficulty in foraging on young fishes inshore. Selectively channelizing macrophyte beds with bottom screens or a mechanical harvester can be an effective management strategy to enhance fish growth in densely-planted lakes. |
| SERIAL CHLOROPHYLL MAPPING AND ITS APPLICATION TO WATER QUALITY ASSESSMENT | Herbert J. Grimshaw | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 213 - 223 | SERIAL CHLOROPHYLL MAPPING AND ITS APPLICATION TO WATER QUALITY ASSESSMENT | During the summer months of 1982 and 1983, an invivo, flow-through, fluorometric method was used to obtain chlorophyll aestimates on a synoptic basis from the upper euphotic zones of two Oklahoma reservoirs (Grimshaw et al. 1985). SYMAP, a computer-based mapping routine was used to generate a total of 73 synoptic chlorophyll isopleth (chloropleth) maps for these reservoirs, and reservoir areas containing persistently high chlorophyll concentrations were delineated statistically. Serial chlorophyll mapping was effective in delineating sources of nutrient pollution, and proved useful in the development of efficient, cost-effective, sampling programs. The greatest strength of the method lies in its suitability for use on water bodies which have not been previously characterized limnologically. Its use permits a rapid transition from descriptive to experimental limnology for water bodies lacking a history of limnological research. |
| PREDICTION OF QUANTILES IN DISTRIBUTIONS OF CHLOROPHYLL aCONCENTRATIONS | Sidney J. Curran Jr.; John W. Wilkinson; Nicholas L. Clesceri | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 202 - 212 | PREDICTION OF QUANTILES IN DISTRIBUTIONS OF CHLOROPHYLL aCONCENTRATIONS | Procedures are described for establishing mean chlorophyll awater quality standards based on the probability and frequency that any specified “maximum†chlorophyll aconcentration will be exceeded by a given mean chlorophyll aconcentration. The models developed employ frequency distribution relationships and provide a means through which water quality standards can be established for mean chlorophyll aconcentrations while accounting for the impacts of peak algal growths. This is felt to be a more appropriate approach than establishing arbitrary maximum chlorophyll a standards. The relationships developed can be used in conjunction with other models to predict the effect that remedial programs could have on the probabilities that chlorophyll a concentrations would exceed desired levels. The procedures permit the establishment of rational sampling programs for compliance/ enforcement monitoring. These models are calibrated on data for North Carolina lakes. The complications arising from the dependency of “maximum†chlorophyll aon sample size is accounted for by these models. A linear regression model is developed for predicting the largest expected chlorophyll aconcentration from the mean chlorophyll aconcentration, and is compared with the model based upon frequency distribution relationships. |
| ALUM INJECTION INTO SEDIMENTS FOR PHOSPHORUS INACTIVATION AND MACROPHYTE CONTROL | Nancy Mesner; Richard Narf | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 256 - 265 | ALUM INJECTION INTO SEDIMENTS FOR PHOSPHORUS INACTIVATION AND MACROPHYTE CONTROL | Aluminum sulfate was injected directly into lake sediments in an attempt to create a phosphorus-limiting environment to control macrophyte growth. The experimental site was located in a shallow lagoon off Lake Wingra, Wisconsin, which historically supports a dense, monotypic stand of Myriophyllumspicatum. A pump and probe mechanism was developed for sediment injection and alum was injected into experimental plots in late May 1986 at a dosage of 200 mg Al3+/L. Following injection, total dissolved phosphorus was reduced to a mean of 70 μg/L in interstitial Water at 13 cm sediment depth, compared to a mean of 460 μg/L in control plots at the same sediment depth. Phosphorus remained significantly lower in treated plots for at least 2 months. Alkalinity and pH were not significantly reduced; dissolved aluminum levels increased immediately following injection, but only in sediment-surface samples in harvested plots. No reduction in biomass attributable to alum treatment was observed during the 1986 growing season. No differences were seen in the percent phosphorus by dry weight in plant vegetation but lower percent phosphorus in root tissue was attributable to the alum treatment. Phosphorus mobilization from sediments and incorporation in plant tissue appears to have been more rapid in alum treated plots compared to controls. |
| ENVIRONMENTAL FACTORS CONTROLLING THE GROWTH AND DISTRIBUTION OF SUBMERSED AQUATIC MACROPHYTES IN TWO SOUTH CAROLINA RESERVOIRS | Richard M. Harvey; Jeannie R. Pickett; Richard D. Bates | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 243 - 255 | ENVIRONMENTAL FACTORS CONTROLLING THE GROWTH AND DISTRIBUTION OF SUBMERSED AQUATIC MACROPHYTES IN TWO SOUTH CAROLINA RESERVOIRS | Factors influencing the growth and distribution of submersed aquatic macrophytes in two South Carolina reservoirs were investigated through the statistical analysis of chemical, physical and biological data obtained throughout the 1984, 1985 and 1986 growing seasons. Comparisons of parameter means between areas with and without plants identified significant differences for depth, Secchi depth, light penetration, dissolved oxygen. Comparisons of parameter and means between areas with and without plants identified significant differences for depth, Secchi depth, light penetration, dissolved oxygen, pH, nitrate-nitrogen, and fetch (exposure). Through logistic multiple regression techniques, Secchi depth, light penetration, surface, dissolved oxygen, and fetch were determined to be important in predicting the presence of submersed aquatic macrophytes. Of the parameters examined, light penetration and fetch appear to have the strongest influence on macrophyte distribution. Light penetration most likely limits macrophyte distribution in the shallow sheltered areas of upper Lake Marion, which experience high suspended solids loadings, and in pelagic regions where the effects of surface waves generally would not reach the bottom. In the shallow, open areas of lower Lake Marion and Lake Moultrie, fetch appears to be the most influential factor. |
| THE RESTRUCTURING OF LITTORAL ZONES | Sandy Engel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 235 - 242 | THE RESTRUCTURING OF LITTORAL ZONES | Littoral zones are centers of community life in shallow lakes and reservoirs. Invertebrates and young fishes forage and seek cover among the bottom and plant habitats found inshore. Because boaters and swimmers scorn dense vegetation, lake shallows are defoliated with chemical herbicides or mechanical harvesters. Such wanton destruction of animal and plant life can be avoided by restructuring littoral zones. This architectural approach views lakes as aquascapes that can be improved for both recreation and biological diversity. A lake use plan is first developed from a hydrographic map depicting summer macrophyte growth and patterns of lake use. The lake is next zoned into areas of similar function. A management strategy is then tailored to each zone. Some lakes are managed for specific functions; others for multiple use. Intensive management is applied to open space zones for swimmers and boaters. Posting speed or time restrictions on power boating in these zones can reduce user conflicts. Prime angling habitat is constructed in other areas by channelization or transplantation. Quiet zones of dense foliage are reserved for waterfowl. Emergent cover is planted on shore for birds and small mammals. Restructuring littoral zones ultimately provides a balanced and integrated approach to enhancing lake recreation without needless loss of community life. |
| DETERMINING STATISTICALLY SIGNIFICANT CHANGES IN WATER POLLUTANT CONCENTRATIONS | Jean Spooner; Catherine J. Jamieson; Richard P. Maas; Michael D. Smolen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 195 - 201 | DETERMINING STATISTICALLY SIGNIFICANT CHANGES IN WATER POLLUTANT CONCENTRATIONS | Water quality variability can be examined to estimate the magnitude of changes in water quality needed to detect significant differences over time. Adjustments can be made to reduce the estimate of variability, thereby decreasing the water quality change required for statistical significance. These adjustments include: accounting for changes in meteorologic and hydrologic conditions through covariate variables in trend analyses; changing the sampling frequency; increasing the number of years in the monitoring scheme; and use of other statistical trend analyses, such as t-tests, linear regression, and time series analyses. Water quality monitoring data was examined from the Idaho Rural Clean Water Program (RCWP) project. Generally, a 30 to 60 percent change in unadjusted geometric mean concentrations is required to document a significant change in water quality. However, adjustments that reduce the estimate of variability can be used to reduce the required concentration change to 20 to 40 percent. |
| BENEFIT/COST ANALYSIS OF NONPOINT SOURCE CONTROL IN THE TILLAMOOK BAY, OREGON WATERSHED | Richard P. Maas; Michael D. Smolen; Jean Spooner; Ann Patchek | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 157 - 162 | BENEFIT/COST ANALYSIS OF NONPOINT SOURCE CONTROL IN THE TILLAMOOK BAY, OREGON WATERSHED | Economics has come to play an increasingly important role in decisions concerning lake protection and restoration. This study of the tillamook Bay, Oregon, nonpoint source control efforts illustrates a methodology by which a benefit/cost analysis can be accomplished for evaluating cost-effectiveness of such projects. Tillamook Bay has been periodically closed to shellfishing for several years because of bacterial contamination. Implementation of agricultural best management practice on about 60 percent of the identified critical sources in the watershed has produced a statistically significant reduction in bay fecal coliform concentrations. With plans for nearly 100 percent implementation by 1989, the bay waters should again meet shellfish water quality standards thereby removing the threat of further closures. Total government costs for the cleanup effort will probably be in the range of six million dollars. This paper develops a benefit/cost analysis to determine the cost effectiveness of this nonpoint source control effort. The analysis shows that the control effort is only marginally economically efficient when only lost commercial shellfishing revenues are considered. However, when the lost revenues from associated recreational activities are considered, the analysis shows that benefits of greatly exceed project costs. |
| LIMNOLOGICAL ANALYSIS OF ONSITE WASTEWATER IMPACTS TO THE SEVEN LAKES AREA OF SNOHOMISH COUNTY, WASHINGTON | George S. Edwards; Thomas J. Belnick; Edward J. Berschinski | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 146 - 156 | LIMNOLOGICAL ANALYSIS OF ONSITE WASTEWATER IMPACTS TO THE SEVEN LAKES AREA OF SNOHOMISH COUNTY, WASHINGTON | A nine-month water quality monitoring program was performed on seven lakes in Snohomish County, Washington to: (1) assess current lake quality, (2) identify potential pollutant loading sources, and (3) recommend appropriate restoration/management strategies. A major concern was the extent to which shoreline on-site wastewater systems were adversely affecting quality of the lakes. Two comprehensive septic leachate surveys of lake shoreline were performed to identify the number of concentrated effluent plumes to the lakes and characterize phosphorus loading from this source. A portable fluorometer specifically indexed to degradation products of wastewater was used with great effectiveness in the surveys. Initial fluorometer screening was followed by surface water and shallow groundwater quality sampling/analyses, site inspections/homeowner interviews, and dye testing to corroborate onsite system failures. Open-water areas of the lakes exhibited good to excellent water quality. However, several localized shallow shoreline areas evinced signs of incipient water quality degradation and coincided with effluent plumes from inadequately treated residential wastewater and discharges of surface water drainage. Management efforts were recommended to minimize pollutant loading by both the above sources. |
| APPLICATION OF INNOVATIVE POLLUTANT TRADING FOR RESERVOIR WATER QUALITY MANAGEMENT IN COLORADO | Gary Mast; Bruce Zander | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 138 - 145 | APPLICATION OF INNOVATIVE POLLUTANT TRADING FOR RESERVOIR WATER QUALITY MANAGEMENT IN COLORADO | Colorado has institutionalized an innovative method for managing reservoir water quality which allows for point/nonpoint source phosphorus trading and for point sources to obtain phosphorus “credit†for controlling nonpoint source phosphorus. The State Water Quality Control Commission and the Environmental Protection Agency have approved this method for use at Dillon Reservoir, a high-altitude water body located in the heart of ski country, serving as a summer recreational resource and primary drinking water supply for the Denver metro area; and Cherry Creek, a plains reservoir which is the most intensely used water body for recreation in Colorado. Both reservoirs are threatened by eutrophication from increased point and nonpoint source nutrients loadings resulting from future growth. This approach has built-in economic and regulatory incentives for application of conscientious nonpoint source control. Dillon Reservoir is the first water body in the country for which this approach has been officially adopted. |
| DETECTING CHANGES IN WATER QUALITY IN THE LAPLATTE RIVER WATERSHED FOLLOWING IMPLEMENTATION OF BMPS | Donald W. Meals | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 185 - 194 | DETECTING CHANGES IN WATER QUALITY IN THE LAPLATTE RIVER WATERSHED FOLLOWING IMPLEMENTATION OF BMPS | The LaPlatte River Watershed in northwestern Vermont is the focus of an intensive land treatment program to control agricultural runoff and a long-term monitoring program to evaluate the effect of these treatments on water quality. Best Management Practices for controlling dairy manure and cropland erosion have been implemented on 90 percent of the priority areas in the Watershed. The 11-year monitoring program includes precipitation and streamflow recording and water sampling for suspended solids, phosphorus, and nitrogen analysis. Interpretation of monitoring data is confounded by incremental implementation of best management practices, climatic and hydrologic variation, and lack of pre-implementation water quality data. Application of four exploratory trend analysis techniques to six years of data from one monitored subwatershed is described. These techniques are (1) linear regression against time; (2) comparison of annual means; (3) analysis of frequency distributions; and (4) paired watershed regression. Results of these analyses suggest significant decreases in sediment and nutrient concentrations and loads since the project began. |
| POWERBOAT ENGINE DISCHARGES AS A NUTRIENT SOURCE IN HIGH-USE LAKES | David D. Hallock; C. Michael Falter | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 172 - 181 | POWERBOAT ENGINE DISCHARGES AS A NUTRIENT SOURCE IN HIGH-USE LAKES | Fuels for modern internal combustion engines contain nitrogen and phosphorus compounds as additives (e.g., alkyl phosphate, amine phosphate, etc.). In addition, nitrogen oxides are formed from atmospheric gases during combustion. In the case of marine engines, exhaust gases and incompletely burned fuel and oil are discharged directly into the water. In situ enclosure experiments were conducted to quantify nitrogen and phosphorus additions from two- and four-cycle outboard engines per liter of fuel consumed. The modern two-cycle outboard engine added to test tanks 8,600 mg carbon dioxide, 300 mg total nitrogen, and 1.0 mg total phosphorus per liter fuel consumed. A motorboat census was conducted on Twin Lakes, Kootenai County, Idaho, throughout the 1986 boating season and annual fuel consumption was estimated. Phosphorus and nitrogen loading to Twin Lakes from motorboat engine discharges were calculated and are low when compared to loading from other sources. |
| STATISTICAL BASIS FOR THE DESIGN AND INTERPRETATION OF THE NATIONAL SURFACE WATER SURVEY, PHASE I: LAKES AND STREAMS | D. James Blick; Jay J. Messer; Dixon H. Landers; W. Scott Overton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 470 - 475 | STATISTICAL BASIS FOR THE DESIGN AND INTERPRETATION OF THE NATIONAL SURFACE WATER SURVEY, PHASE I: LAKES AND STREAMS | The primary objectives of Phase I of the National Surface Water Survey were to determine the number of acidic or potentially acidic lakes and streams, their location, and their physical and chemical characteristics. To meet these objectives, a statistically designed survey was implemented. For both lakes and streams, probability samples were drawn in order to make population estimates within known confidence bounds. The National Lake Survey utilized a stratified design in which the population consisted of lakes identified on 1:250,000 maps in regions of interest. Strata were defined on the basis of region, subregion, and mapped alkalinity classes. A systematic random sample was taken within each stratum. The National Stream Survey was also stratified by region and subregion, but because a list of the extensive number of streams was not feasible, a two-stage sampling scheme utilizing a point frame was employed within strata. Both designs are flexible in that inferences about any subpopulation of interest can be made. However, because sampling intensities varied among strata, stratum-specific weights must be used when making estimates for those subpopulations that combine or cut across strata. |
| CRITICAL DESIGN AND INTERPRETIVE ASPECTS OF THE NATIONAL SURFACE WATER SURVEY | Jay J. Messer; Dixon H. Landers; Rick A. Linthurst; W. Scott Overton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 463 - 469 | CRITICAL DESIGN AND INTERPRETIVE ASPECTS OF THE NATIONAL SURFACE WATER SURVEY | The National Surface Water Survey represents a unique design for determining, with known confidence, the numbers and percentages of lakes and streams in large regions of the United States that have chemical characteristics that can be interpreted in light of present conditions, past damage, and future potential impacts of acid deposition. The Survey also provides a framework for interpreting future, site-specific intensive studies in a regional context. This paper describes the basis for this design, as well as some strengths and weaknesses of regional, as opposed to the more traditional single-system, approaches to lake and stream management. |
| EFFICACY AND CHEMICAL EFFECTS OF BASE TREATMENT TO FLOWING WATER SYSTEMS | W. Peter Saunders Jr.; James E. Fraser | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 452 - 459 | EFFICACY AND CHEMICAL EFFECTS OF BASE TREATMENT TO FLOWING WATER SYSTEMS | Three techniques of stream liming were analyzed with respect to dissolution efficiency, ability to treat fluctuations in flow and effects on selected water quality parameters: a slurried-powder mechanical doser, a rotary drum system, and a limestone aggregate stream barrier. All achieved similar minimum levels of alkalinity and pH. The doses of calcium carbonate produced by both mechanical treatment methods were relatively unaffected by flow while the limestone barrier lost effectiveness at higher flows. Analysis of changes in concentrations of metals (particularly aluminum) indicated a complex interaction between base material addition and metals. The base material added by the slurried-powder doser appears to have contributed to an observed increase in total aluminum concentrations downstream of the doser. The limestone barrier appears to have acted as a sink for aluminum during low flows, subsequently releasing the metal during high flows. The treatment methods reviewed all appear capable of achieving water quality targets under specific conditions. Care must be taken, however, in selection of materials in order to produce desirable reductions in potentially toxic constituents. |
| MEASUREMENT UNCERTAINTY IN THE NATIONAL SURFACE WATER SURVEY | C. E. Mericas; Robert D. Schonbrod | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 488 - 497 | MEASUREMENT UNCERTAINTY IN THE NATIONAL SURFACE WATER SURVEY | The National Surface Water Survey is a three-phase project conducted by the U.S. Environmental Protection Agency and designed to document the chemical and biological condition of surface waters considered susceptible to acidic deposition. During the Eastern Lake Survey - Phase l, 1,929 lake samples, including 125 field duplicates, and 245 field blanks were collected. Duplicate and blank samples were used to estimate system precision and quantitation limits for each of 19 chemical parameters. Precision estimates are typically calculated as a single value, based upon data at or above the quantitation limit, and are not applicable below that limit. Where sufficient data are available, a relationship may be developed between concentration and precision. The resulting model may be used to estimate measurement uncertainty at any given concentration, thus supplying precision information for very low concentration samples. Examples of the development of measurement uncertainty models for 19 selected analytes are presented and discussed. |
| QUALITY ASSURANCE PROGRAM DESIGN FOR LAKE MONITORING | M. D. Best; M. J. Miah | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 482 - 487 | QUALITY ASSURANCE PROGRAM DESIGN FOR LAKE MONITORING | An effective, economical quality assurance program applied to lake monitoring uses a minimum number of quality assurance samples to provide maximum information about overall data quality. The resulting estimates of data quality can be expressed quantitatively as measures of precision, accuracy, representativeness, and comparability, The completeness of a data set can be assessed during the verification process and by an independent review (data audit). For a particular survey of lakes, the number and the types of quality assurance samples needed to evaluate measurement precision and accuracy can be calculated by identifying the components of potential variability in the data during preliminary field investigations (pilot studies) can be used to estimate the level of confidence associated with the routine sample measurements from the survey. The U.S. Environmental Protection Agency's National Surface Water Survey used laboratory performance evaluations, pilot studies, and measurements of quality assurance and quality control samples. This paper outlines the methods used for determining the confidence limits of data from the Eastern Lake Survey-Phase I and from the Phase II pilot study and spring sampling, including calculation of the mean and the variance of the observed measurement values that the analytical laboratories reported for audit samples. By assigning error limits to the confidence interval of the observed values, an equation was solved for the unknown number of replications (audit samples) needed to achieve the specified data quality objectives. Results of these calculations were used to determine the numbers of quality assurance samples needed for the Phase II summer and fall sampling. Recommendations for applying this approach to other monitoring projects include considerations of the size and complexity of the survey, the budgetary and logistical constraints, and the amount of information available regarding laboratory performance. |
| ACID–BASE STATUS OF SURFACE WATERS IN THE SOUTHERN BLUE RIDGE: A COMPARISON OF RESULTS FROM THE NATIONAL SURFACE WATER SURVEY | Keith N. Eshleman; D. James Blick; Philip R. Kaufmann; Mark E. Mitch; Sharmon M. Stambaugh; Jay J. Messer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 476 - 481 | ACID-BASE STATUS OF SURFACE WATERS IN THE SOUTHERN BLUE RIDGE: A COMPARISON OF RESULTS FROM THE NATIONAL SURFACE WATER SURVEY | The primary objective of the National Surface Water Survey was to determine the percentages of acidic and low acid neutralizing capacity surface waters in regions of the United States thought to be potentially susceptible to acid deposition effects. The Southern Blue Ridge Province is a region of the United States known to receive wet deposition with a pH less than 4.6 and was expected to contain predominantly low acid neutralizing capacity waters. Both the Eastern Lake Survey and the National Stream Survey sampled surface waters in the Southern Blue Ridge, thereby providing a unique opportunity to compare and contrast the “index†chemistry of lakes and streams in the region. Population descriptions for such important chemical variables as acid neutralizing capacity, calcium, and sulfate are remarkably similar, despite the fact that lakes were sampled at fall turnover, while streams were sampled in the spring and early summer. The similarity of lake and stream chemistries reflects the large number of drainage lakes and reservoirs in the region which typically have short retention times. Of the variables compared in this paper, only the pH distributions were appreciably different. |
| USE OF ACID LAKE REACIDIFICATION MODEL (ALaRM) TO ASSESS IMPACT OF BOTTOM SEDIMENTS ON CALCIUM CARBONATE TREATED LAKES | Joseph V. DePinto; Richard D. Scheffe; Thomas C. Young; William G. Booty; James R. Rhea | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 421 - 429 | USE OF ACID LAKE REACIDIFICATION MODEL (ALaRM) TO ASSESS IMPACT OF BOTTOM SEDIMENTS ON CALCIUM CARBONATE TREATED LAKES | A mathematical model (ALaRM) for predicting the reacidification profile of calcium carbonate treated lakes has been calibrated and confirmed using data from two Lake Acidification Mitigation Project (LAMP) lakes. This manuscript focused on the use of ALaRM to evaluate the relative impact of bottom sediment processes on the reacidification rate of the LAMP lakes. Prior to liming the lakes exhibited annual average sediment-to-water ANC fluxes of 194 and 240 meq/m2-yr for Woods Lake and Cranberry Pond, respectively. Following liming there was a period of net water-to-sediment ANC flux due to a reversal of the gradients of ANC-determining chemical species, indicating a buffering effect of bottom sediments on water column acid-base chemistry. A sensitivity analysis indicated that calcite treatment of sediments as well as the water column could mitigate the sediment reacidification-accelerating effect. |
| CONDITIONS FOR REESTABLISHMENT OF BROOK TROUT SALVELINUS FONTINALIS) POPULATIONS IN ACIDIC LAKES FOLLOWING BASE ADDITION | Steven P. Gloss; Carl L. Schofield; Robert L. Spateholts | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 412 - 420 | CONDITIONS FOR REESTABLISHMENT OF BROOK TROUT SALVELINUS FONTINALIS) POPULATIONS IN ACIDIC LAKES FOLLOWING BASE ADDITION | Some lakes with an historical record of fish populations have undergone acidification and fish no longer exist in these systems. Toxicity data suggest that the inability of fish to survive in these acidic environments is due to increased concentrations of hydrogen ion (H+) and aluminum (Al+++) in the water column. To reestablish fish populations in lakes of this kind it is necessary to (1) determine that fish are no longer present, (2) demonstrate that fish either cannot or have limited potential to survive in the systems, and (3) change the water quality, and demonstrate increased survival of fish under differing chemical conditions. We examined two acidic lakes (Woods Lake, pH ~5.0 and Cranberry Pond, pH ~4.8) for the first two conditions by conducting fisheries surveys and in situ bioassays using fingerling (age 0) brook trout (Salvelinus fontinalis). Woods Lake was also stocked with brook trout in the fall of 1984 and overwinter survival of two age classes determined. Emigration from the lake accounted for a relatively small percentage of the approximately 90 percent mortality in these stocked fish over winter. Neither acclimation procedures or experimental selection of brook trout for acid tolerance improved survival. Prior to, during, and after calcium carbonate addition to the lakes in the early summer of 1985 an extensive series of in situ bioassays was conducted that showed significantly improved survival of both age 0 and 1 brook trout after liming. Interactive effects of temperature, pH, and aluminum levels were evident during these experiments. No detrimental effects of liming on fish survival were observed. |
| ASSESSMENT OF E. COLI, ENTEROCOCCI, AND FECAL COLIFORM BACTERIA IN A RECREATIONAL FLOATWAY | Jack D. Milligan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 163 - 171 | ASSESSMENT OF E. COLI, ENTEROCOCCI, AND FECAL COLIFORM BACTERIA IN A RECREATIONAL FLOATWAY | A study was conducted on a recreational fioatway in northeast Alabama to assess EPA's new bacteriological criteria. In relation to the new criteria, the floatway was found to be more contaminated compared to the longstanding fecal coliform criterion. High correlations were found between fecal coliform concentrations and E. Coliand enterococci concentrations. Regression models were developed which enable the prediction of new criteria values from historical fecal coliform data. |
| ECOLOGICAL EFFECTS OF LIMING IN A CAPE COD KETTLE POND: A NOTE FOR FISHERIES MANAGERS | Ann Bergquist Shortelle; Elizabeth A. Colburn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 436 - 443 | ECOLOGICAL EFFECTS OF LIMING IN A CAPE COD KETTLE POND: A NOTE FOR FISHERIES MANAGERS | Some Massachusetts lakes are experimentally limed to raise water column pH and alkalinity to mitigate the effects of acidification and to aid in fisheries management. This study evaluated the ecological effects of liming by comparing and contrasting several water chemistry and ecological variables in two softwater ponds. Physical, chemical, and biological parameters have been monitored in Great Pond, Truro, Massachusetts, before and following the addition of lime in March, 1985. Ryder Pond, Truro, Massachusetts, a nearby similar kettle pond that has never been limed, was concurrently monitored as a reference. Results with implications for water resources and fisheries management strategies are presented. Micropterusdolomieui(smallmouth bass) recruitment was successful following liming. Zooplankton and chironomids, both fish prey, declined after liming, however. Elevated calcium concentrations persisting after pH has declined may permit longer intervals between liming events. |
| CHEMICAL CHANGES IN WHITE DEER LAKE (PENNSYLVANIA) BEFORE AND AFTER LIMESTONE APPLICATION | J. L. Dudley; P. T. Bradt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 430 - 435 | CHEMICAL CHANGES IN WHITE DEER LAKE (PENNSYLVANIA) BEFORE AND AFTER LIMESTONE APPLICATION | The ice application of agricultural limestone (220 mesh, 5 tons/ha) to White Deer Lake in February 1985 followed four seasons of baseline data collection. Immediate chemical changes in the lake occurred for total alkalinity, specific conductance, calcium, Secchi depth, magnesium, and silica as the limestone continued to dissolve for nearly seven months. In October 1985 White Deer Lake began to exhibit clear patterns of re-acidification such as declining total alkalinity, and changes in specific conductance, calcium, and magnesium following the dilution of the treated waters after Hurricane Gloria. Reacidification continued through the summer of 1986. Monitoring continues at White Deer Lake. |
| PLANKTON COMMUNITY RESPONSE TO THE CHEMICAL NEUTRALIZATION OF THREE ACIDIFIED WATERS IN THE ADIRONDACK MOUNTAIN REGION OF NEW YORK STATE | Clifford A. Siegfried; J. W. Sutherland; S. O. Quinn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 3 | 1 | 1987 | 444 - 451 | PLANKTON COMMUNITY RESPONSE TO THE CHEMICAL NEUTRALIZATION OF THREE ACIDIFIED WATERS IN THE ADIRONDACK MOUNTAIN REGION OF NEW YORK STATE | The response of the phytoplankton and zooplankton communities of three acidic Adirondack lakes to chemical neutralization is reported. The addition of base to the three lakes effectively neutralized acid conditions, raising pH from ~4.50 to 6.02 to 7.3. Concentrations of major ions were generally unaffected by neutralization treatment but aluminum concentrations were reduced. The phytoplankton and planktonic rotifer communities were initially decimated by the water column treatments but recovered within the first growing season following treatment. Species richness and standing crops of phytoplankton and rotifers approached or exceeded pre-treatment values within a year of neutralization. The crustacean community was generally slower to respond to base additions. Phytoplankton, rotifer, and crustacean community composition was changed in all lakes following treatment. |
| AN EVALUATION OF THE ACCURACY OF ESTIMATING CHLOROPHYLL A IN TWO OKLAHOMA RESERVOIRS | Herbert J. Grimshaw; Gary L. Shapiro; Douglas B. Jester; Daniel R. Butler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 293 - 301 | AN EVALUATION OF THE ACCURACY OF ESTIMATING CHLOROPHYLL A IN TWO OKLAHOMA RESERVOIRS | Accuracy of the in vivo method for estimating chlorophyll was evaluated on two Oklahoma reservoirs that are morphometrically and hydrologically dissimilar. The coefficients of correlation between chlorophyll a contents estimated fluorometrically and determined spectrophotometrically on Overholser and Lawtonka Reservoirs were 0.767 and 0.970, respectively. The mean of the error distribution on Overholser Reservoir was 0.07 ±3.12 μg/L (n = 30), and 0.52 ±2.11 μg/L (n = 150) on Lawtonka Reservoir. Regression equations were developed to permit prediction of chlorophyll a content from fluorometric measurements, and experiments were conducted to determine the factor(s) responsible for observed error. With proper calibration of the fluorometer, accuracy of the fluorometric estimates was equivalent to spectrophotometric precision. Therefore, in vivo fluorometry is uniquely suited for synoptic analysis of distribution of algal biomass and has wide application for reservoir management (Grimshaw and Shapiro, in prep.). |
| USE OF EXCLOSURES TO ASSESS THE IMPACT OF COPPER SULFATE TREATMENTS ON PHYTOPLANKTON | Edward B. Swain; Bruce A. Monson; Robert W. Pillsbury | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 303 - 308 | USE OF EXCLOSURES TO ASSESS THE IMPACT OF COPPER SULFATE TREATMENTS ON PHYTOPLANKTON | The impact of a whole-lake copper sulfate treatment is difficult to assess because it is uncertain how the lake would have behaved if the copper had not been added, that is, no control exists. However, control can be created by isolating lake water in an enclosure prior to the copper sulfate treatment. The enclosure, by excluding copper, functions as an exclosure. By comparing the exclosure and the lake, the true impact of the copper treatment can be assessed. In this study, small (1 m diameter) polyethylene enclosures were used to study the effect of copper sulfate treatments of Halsteds Bay of Lake Minnetonka, Minn. Specific rates of photosynthesis were depressed in the lake only on the day of the copper treatment, after which rates exceeded the control for several weeks. In the period immediately after the copper treatment, green algae, diatoms, and nonnitrogen-fixing blue-greens were more common in the lake than in the control, but gradually nitrogen-fixing blue-green algae became dominant again. Therefore, the major effect of the copper sulfate treatment is a secondary succession of the pnytoplankton, analogous to the succession of terrestrial plants after a forest fire. In the lake studied, no residual copper toxicity to the phytoplankton was apparent after the first 24 hours. |
| BOD DYNAMICS IN SMALL EUTROPHIC LAKES IN RELATION TO ARTIFICIAL MIXING | Timothy K. Cross; Robert C. Summerfelt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 286 - 292 | BOD DYNAMICS IN SMALL EUTROPHIC LAKES IN RELATION TO ARTIFICIAL MIXING | Seasonal and annual variation in the biochemical oxygen demand of the water column (WBOD) and the sediment (SBOD) are described for two small central Iowa lakes based on sampling over 57 consecutive months, 1977-82. A correlation analysis was done to determine the relationship between WBOD and SBOD to 15 physical and chemical variables using composite values for the whole lake and for the top, middle and bottom-most strata on each sampling date. The best single variable model for predicting volume-weighted WBOD was mean lake chlorophyll a concentration: WBOD = 1.79 + 0.032 (chlorophyll a). There were no significant correlations between SBOD and any of 15 environmental variables, but in the control lake, not artificially destratified, SBOD and chlorophyll a (-) and ammonia (+) showed significant correlations. Artificial destratification increased the vertical distribution of oxygen and chlorophyll a, reduced peaks of algal blooms, increased near-bottom water temperature and oxygen concentration, and reduced SBOD and ammonia. |
| EXPERIENCES OF LONG-TERM DESTRATIFICATION IN A WATER SUPPLY IMPOUNDMENT IN CENTRAL ILLINOIS | Raman K. Raman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 271 - 276 | EXPERIENCES OF LONG-TERM DESTRATIFICATION IN A WATER SUPPLY IMPOUNDMENT IN CENTRAL ILLINOIS | Lake Eureka, III., was created in 1942 primarily to serve as a water supply source for the city of Eureka. Because of complaints about taste and odor in the finished waters, the city abandoned the lake and switched to ground water as the water supply source in 1979. A detailed taste and odor investigation indicated that high concentrations of iron and manganese, and the dominance of blue-green algae in the lake waters, contributed to the problems in the finished waters. Lake destratification using a low-energy mechanical destratifier in the deepest part of the lake in combination with chelated copper sulfate application to control blue-green algae was tried in 1981 to enhance the lake water quality characteristics. The aerator has been found capable of destratifying the lake and maintaining adequate oxygen levels. Iron and manganese concentrations in the deep waters have been reduced by 95 to 97 percent from the predestratification levels. Chlorine demand values have been reduced by more than half, and problem-causing blue-green algae have been brought under control. The city reverted back to the lake as its water supply source in April 1982, saving 50 to 60 percent in the water treatment plant's annual operating costs over the past three years. |
| RESTORATION OF LAKE BALLINGER | Harry L. Gibbons Jr.; Stephen C. Wagner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 277 - 280 | RESTORATION OF LAKE BALLINGER | Lake Ballinger is a 40 ha (100 acres) eutrophic lake in the city of Mountlake Terrace, Wash. The lake's very poor water quality characteristics have been brought about by excessive nutrient loadings from the watershed and internal cycling of phosphorus during periods of hypolimnetic anoxia. A two-phase restoration project was undertaken to improve the water quality of the lake. Phase I was the restoration of Hall Creek (the major surface water inlet) by establishing two sedimentation basins and rehabilitating the stream bank. Phase II was the construction of a hypolimnetic injection/withdrawal system to enhance the dissolved oxygen levels in that strata and remove phosphorus-rich hypolimnetic waters. The internal cycling of phosphorus has been reduced from an annual loading of 109 kg in 1980 to 17 kg in 1984. Data analysis indicates that further watershed management efforts are needed to control the increasing loading of nutrients into Lake Ballinger and achieve a long-term improvement in the lake's water quality. |
| WATERFOWL WASTE AS A SOURCE OF NUTRIENT ENRICHMENT IN TWO URBAN HYPEREUTROPHIC LAKES | Paul T. Gremillion; Ronald F. Malone | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 319 - 322 | WATERFOWL WASTE AS A SOURCE OF NUTRIENT ENRICHMENT IN TWO URBAN HYPEREUTROPHIC LAKES | A study to determine the influence of waterfowl waste on the nutrient budget of two small, urban, hypereutrophic lakes has been conducted on the University Lakes System in Baton Rouge, La. Campus Lake (3.7 ha surface area, 1.1 m mean depth), which supports a resident flock of 57 ducks and 5 geese, receives about 7 percent of its total annual phosphorus loading from the waterfowl. College Lake (1.4 ha surface area, 1.3 m mean depth) has a resident flock of 14 ducks and 17 geese and receives about 8 percent of its annual phosphorus budget in waterfowl waste. This loading is slightly high considering the other loading sources to the lakes. The management implications of including waterfowl populations in lake plans are discussed. |
| FISHERIES MANAGEMENT | Steven R. McComas; George Boronow; Duane Shodean; Joel Schilling | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 447 - 450 | FISHERIES MANAGEMENT | |
| AQUATIC PLANT MANAGEMENT | Neal O'reilly; Joel Schilling; James C. Schmidt; Ray Kipp; Sandy Engel; Peter Newroth | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 443 - 446 | AQUATIC PLANT MANAGEMENT | |
| HAYES LAKE: RECLAMATION OF A WINTERKILL LAKE | Charles S. Holt; Roger A. Mackedanz; Joseph J. Grabowski | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 281 - 285 | HAYES LAKE: RECLAMATION OF A WINTERKILL LAKE | In an attempt to create lake-type fishing in northwestern Minnesota, legislative funds were provided to construct a lake near the Canadian border by damming the north fork of the Roseau River. The lake was to serve as a focus for Hayes Lake State Park. Soon after the creation of this impoundment, winterkill conditions developed from incomplete burning of the vegetation in the reservoir basin prior to flooding. Limnological sampling conducted between 1979 and 1983 confirmed the winterkill conditions, with dissolved oxygen levels of 4 ppm at the surface to 0.4 ppm at lake bottom. In January 1984, a bottom water drawdown device was installed. Tests conducted after its installation showed that the dissolved oxygen level had been restored to 6.7 ppm at the surface and 3.5 ppm at the lake bottom. After the installation of the pipe, winter fishing activity increased along with other recreational uses. |
| COMPARISON OF SULFATE REDUCTION RATES IN LABORATORY MICROCOSMS, FIELD MESOCOSMS, AND IN SITU AT LITTLE ROCK LAKE, WISCONSIN | Todd E. Perry; Lawrence A. Baker; Patrick L. Brezonik | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 309 - 312 | COMPARISON OF SULFATE REDUCTION RATES IN LABORATORY MICROCOSMS, FIELD MESOCOSMS, AND IN SITU AT LITTLE ROCK LAKE, WISCONSIN | Model systems examine the effect of several treatments simultaneously, but how well do they simulate natural lake systems? In our studies at Little Rock Lake, Wis., we measured sediment-water fluxes of sulfate in laboratory sediment-water microcosms, in situ limnocorrals, and the whole lake. Treatments in the laboratory sediment-water microcosm experiment included sediment type, temperature, pH, and [SO42 -]; sulfate fluxes were determined by mass balance. Treatments in the field mesocosms (4 m diameter 1.5 m depth, open to sediment) included (in duplicate): control (pH 6.0), pH 5., 5.0, and 4.5 (H2SO4) and pH 5.0 (HCl). Weekly additions of acid maintained treatment pH throughout the summer. Results from these experimental systems are compared with sulfate fluxes measured in the lake (by porewater profiles and a whole-lake budget). Potential problems associated with experimental systems are discussed in the context of these experiments. |
| ENCLOSURE EXPERIMENTS: THE EFFECTS OF PLANKTIVOROUS FISH | D. J. Mc Queen; J. R. Post | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 313 - 318 | ENCLOSURE EXPERIMENTS: THE EFFECTS OF PLANKTIVOROUS FISH | Limnologists manipulating segments of freshwater ecosystems with enclosures frequently exclude or ignore fish populations. Both courses of action can seriously bias results because a strong negative correlation (r = .77) exists between fish and zooplankton biomass, and failure to account for planktivore effects will jeopardize an accurate interpretation of zooplankton results. These effects are also transmitted to the phytoplankton community. In eutrophic lakes, enclosures containing planktivore bio-masses of less than 20 kg/ha often support populations of large Daphnia, which can have strong negative impacts (r = .81) on phytoplankton biomass. When planktivore biomass is more than 20 kg/ha, large Daphnia cannot survive and zooplanktonic regulation of phytoplankton biomass is not observed. We conclude that even though enclosure experiments may not include the effects of planktivores, the latter cannot be ignored. |
| RESPONSE OF LAKE SAMMAMISH TO URBAN RUNOFF CONTROL | J. I. Shuster; E. B. Welch; R. R. Horner; D. E. Spyridakis | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 229 - 234 | RESPONSE OF LAKE SAMMAMISH TO URBAN RUNOFF CONTROL | A seasonal phosphorus model was used to predict the effect of proposed watershed development on water quality in Lake Sammamish, Wash. The model was calibrated and verified using daily loadings from two separate annual data sets. Phosphorus yields were scaled from literature values using actual loadings. Results indicate that substantial runoff controls should be applied to maintain water quality at its present, near oligotrophic state and prevent its return to a prewastewater diversion mesotrophic-eutrophic state. |
| PUBLIC ACCESS INVESTMENT POLICY | Jeff Pagels | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 235 - 238 | PUBLIC ACCESS INVESTMENT POLICY | Most States are, by law, responsible for providing public access to navigable waters. How that access is provided varies in quality, efficiency, politics, and procedure from state to state. Federal grants for developing access sites are anticipated to increase, prompting the question: If we had a million dollars to spend on public access tomorrow, where would we spend it? This paper critically reviews the access development procedures of many states and provinces of Canada, examining innovative public policy planning procedures such as decision analysis, simulations, stakeholder analysis, systems analysis, multiattribute utility theory, and operations research. The author recommends optimal pathways to sound public investments for public access. The conclusions indicate that scientific formulas do not work well in determining where access sites should be developed. Rather, a careful understanding of the social and political processes really becomes the important decision criterion. |
| DYNAMIC (MATHEMATICAL) MODELING OF LAKE PROCESSES FOR MANAGEMENT DECISIONS | Mark J. Hanson; Heinz G. Stefan; Michael Riley | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 225 - 228 | DYNAMIC (MATHEMATICAL) MODELING OF LAKE PROCESSES FOR MANAGEMENT DECISIONS | Selecting a lake improvement method can be facilitated by computer simulation of the effects of various alternatives on lake water quality. Dynamic simulation of cause/effect relationships on the most important physical, chemical, and biological processes encountered in a lake allows extrapolation to future conditions on a rational basis. Not all lake processes are understood well enough to be properly modeled. However, features such as temperature stratification, turbidity, nutrient levels, and phytoplankton populations have been simulated successfully. A discussion of types of lake improvement techniques which can be simulated and those which cannot be simulated will be made. Examples of simulations evaluating improvement techniques will be given. Dynamic water quality simulation is an efficient and rational tool to compare quality and cost effectiveness of certain lake improvement techniques. |
| DILUTION EFFECTS ON MINNEAPOLIS CHAIN OF LAKES WATER QUALITY | John B. Erdmann | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 215 - 219 | DILUTION EFFECTS ON MINNEAPOLIS CHAIN OF LAKES WATER QUALITY | The effect of dilution on lake water quality is analyzed using steady-state mass-balance phosphorus models. The critical (that is, no-effect) phosphorus (P) concentration for dilution water exceeds the lake's predilution concentration by the factor 1/(1 - R), if the retention coefficient R is constant. On the other hand, if the P settling velocity is constant, then the critical dilution water concentration equals the lake's predilution concentration. Dimensionless response surfaces are presented for these alternative models. Data from many lakes support the first model. Applied to the Minneapolis Chain of Lakes, this model investigated water quality effects of augmentation for water level maintenance. Surprisingly, augmenting with Mississippi River water—for which facilities already exist—benefits water quality almost as much as would high-quality ground water. |
| A WIND–PHYTOPLANKTON MODEL FOR LAKE WATER QUALITY MANAGEMENT | Sally L. Marquis; Brian W. Mar; Eugene B. Welch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 220 - 224 | A WIND-PHYTOPLANKTON MODEL FOR LAKE WATER QUALITY MANAGEMENT | Models of wind-induced vertical mixing and nitrogen-limited phytoplankton growth produced data for a management model for Moses Lake, a hypereutrophic lake in eastern Washington. This approach preserved the simplicity and flexibility of the management model without sacrificing the advantages offered by complex models. The model considers two-week periods and was calibrated and verified with limitations. While the model predicts bloom times and maximum well, the decay of blooms is not predicted well in one out of three cases. The model evaluated scenarios of dilution water inputs and best management practices strategies. For the Moses Lake watershed a constant dilution water addition of 5.7 m3/sec produced significantly greater chlorophyll a reductions when compared against no dilution or 30 m3/sec springtime dilution scenerios. Reductions in chlorophyll a were demonstrated with decreased nutrient loading into the lake (such as controlled fertilizer additions to irrigated land). |
| NEW DIRECTION FOR LAKE MANAGEMENT IN WISCONSIN | Carolyn Rumery; Stephen M. Born; Richard E. Wedepohl | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 239 - 243 | NEW DIRECTION FOR LAKE MANAGEMENT IN WISCONSIN | Wisconsin's new Lake Management Program began in 1985 after a two-year hiatus when no comprehensive state program existed to address lake management issues. In 1974, a nationally recognized, pioneering state-local co-operative program in lake renewal and protection had been established. After eight years, funding for administration and implementation of this program was eliminated, despite major accomplishments in the areas of education and involvement of local citizens in lake management, preparation of lake management plans, and implementation of lake projects, all of which helped advance the science of lake renewal and management. A combination of program deficiencies, many of which are generic to any resource management program, contributed to the lake program's eventual demise. These deficiencies included leadership and administrative weaknesses, difficulties in coordinating this program with others affecting lake resources, a focus on short-term remedial strategies at the expense of long-term solutions to lake problems, and the reactive role of the state regarding local lake districts and programs. The new program for lake management has been designed to remedy those deficiencies and to build upon Wisconsin's past experience in managing lake resources. |
| THE EMPLOYMENT OF MACROPHYTE TRANSPLANTING TECHNIQUES TO ESTABLISH POTAMOGETON AMPLIFOLIUS BEDS IN CHAUTAUQUA LAKE, NEW YORK | Thomas A. Storch; Jimmy D. Winter; Constance Neff | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 263 - 266 | THE EMPLOYMENT OF MACROPHYTE TRANSPLANTING TECHNIQUES TO ESTABLISH POTAMOGETON AMPLIFOLIUS BEDS IN CHAUTAUQUA LAKE, NEW YORK | Macrophyte transplant experiments were conducted between 1981 and 1985 in Chautauqua Lake, N.Y., to evaluate the feasibility of reestablishing Potamogeton amplifolius and increasing its abundance in the lake. Transplants with attached rhizomes and cuttings without rhizomes grew readily following transplanting. In the summer, growth rates of established plants ranged from 0.1 to 0.9 cm/day and new propagules grew from 0.7 to 0.8 cm/day. Three to four years after transplanting, numbers of P. amplifolius plants at both sites remained constant at 60 to 68 percent of the original number of transplants. Although the plants actively propagated by rhizomal and stem vegetative reproduction, the stands of transplanted P. amplifolius failed to spread more than a meter beyond the original transplant sites after four years. Heavy encroachment by other macrophyte species may have prevented expansion of the transplant stands. |
| APPLICATION OF HARVEST, MECHANICAL SIMULATION MODEL, AS AN OPERATIONAL AQUATIC MACROPHYTE MANAGEMENT DECISION TOOL | Tommy D. Hutto; Bruce M. Sabol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 267 - 270 | APPLICATION OF HARVEST, MECHANICAL SIMULATION MODEL, AS AN OPERATIONAL AQUATIC MACROPHYTE MANAGEMENT DECISION TOOL | The computer program HARVEST deterministically simulates all important aspects of an aquatic macrophyte harvesting operation. It runs on a personal computer and can simulate any current or proposed harvesting system operating in any realistic aquatic macrophyte-infested environment. The inputs, logic, assumptions, and outputs of the model are described. Its application in evaluating the cost and effectiveness of harvesting programs is demonstrated. |
| LIGHT REDUCTION TECHNIQUES FOR AQUATIC PLANT CONTROL | F. Hugh Dawson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 258 - 262 | LIGHT REDUCTION TECHNIQUES FOR AQUATIC PLANT CONTROL | Moderation of aquatic plant growth by changing the primary growth control factor, light, is an economically viable and ecologically acceptable technique for many lake and stream habitats. In open unshaded waters, great potential exists for plant growth either by large plants (macrophytes) or algae. Although other factors such as nutrients affect growth, without light no plant growth would occur. Attempts to eradicate macrophytes are likely to be unsuccessful and may lead to unstable or extreme situations such as dense algal blooms or monotypic plant stands. The absence of macrophytes, particularly in streams, also can lead to a poor aquatic community. Techniques for moderating plant growth include (1) intercepting light above the water by bank vegetation or at the water's surface by opaque materials, or by redesigned lake or stream margins; (2) reducing light penetration of the water by the action of bottom-feeding fish or of boats, the addition of dyes, or the redesign of waterbodies to maintain materials in suspension; (3) confining macrophytes to deeper water (redesigning margins, protecting marginal plants, and using netting); and (4) combining the detrimental effects of environmental factors on plants with their physiological responses (differential cutting to maintain very dense and very sparse plant stands). Surveys to identify the extent of the problem and potential solutions must be emphasized. No universal solution exists and apparently similar sites may vary subtly but significantly. |
| COMMUNITY MANIPULATION FOR MACROPHYTE MANAGEMENT | Stanley A. Nichols | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 245 - 251 | COMMUNITY MANIPULATION FOR MACROPHYTE MANAGEMENT | Diverse, moderately dense stands of aquatic plants in a lake's littoral zone benefit fish and wildlife and the functioning of the littoral ecosystem. Certain plant species are aesthetically pleasing and do not hamper recreational water uses. The technology is available to manipulate community structure, to increase diversity, and to select for desirable species. However, this technology has not been used in community manipulation strategies. This paper discusses the beneficial and negative attributes of a number of aquatic species common to the north central United States, discusses the technologies available for community manipulation, proposes a management scheme for University Bay of Lake Mendota, and urges field testing of ideas so that community manipulation may provide consistent, predictable, and beneficial results. |
| EURASIAN WATERMILFOIL MANAGEMENT USING NEWLY DEVELOPED TECHNOLOGIES | Peter R. Newroth; Roger J. Soar | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 252 - 257 | EURASIAN WATERMILFOIL MANAGEMENT USING NEWLY DEVELOPED TECHNOLOGIES | In British Columbia, Canada, managing Eurasian water-milfoil (Myriophyllum spicatum L.) integrates harvesting, tillage, bottom barrier applications, and diver-operated dredging methods in annual control programs in nine lakes. Two tillage technologies developed in British Columbia for removing plant roots in high use public areas are not known to have been applied in other jurisdictions. Barge-mounted rototillers achieve 80 to 97 percent reductions in stem densities in water depths up to 3.5 m. An amphibious cultivator is operated in water up to 1.25 m deep with similar effectiveness at lower unit cost and several times higher treatment rates. Both tillage machines may be operated in fall and spring and are particularly suitable during periods of lake drawdown. An independent researcher is developing applications of high power ultrasound to control Eurasian watermilfoil. Effects of laboratory experiments include damage to plant cells and tissues with single exposures of ultrasound for several seconds. This technology promises advantages for management and high levels of effectiveness in treatment of shoot and root tissues; current research is concentrated on reducing the exposure time required to kill meristematic tissues. |
| WATER QUALITY MANAGEMENT IN A DRINKING WATER RESERVOIR | G. Dennis Cooke; Robert E. Carlson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 363 - 371 | WATER QUALITY MANAGEMENT IN A DRINKING WATER RESERVOIR | Lake Rockwell provides drinking water to Akron, Ohio. Algae and macrophytes cause increased treatment costs, user complaints, and concerns about water quality standards. The reservoir is very eutrophic. A diagnostic study performed in the laboratory with intact cores taken from littoral and anoxic sediments determined that oxic and anoxic sediments have a very high potential for phosphorus release. Only 19 percent of annual phosphorus external loading occurs between May and October, but apparently this summer loading triggers algal blooms in the upper reservoir that are transported downstream. Winter loading contributes to sediment phosphorus, and thus, to summer internal loading. Preliminary evaluations of proposed management steps revealed that harvesting of Myriophyllum spicatum that included root crown removal produced summer-long biomass control after a single harvest. Water quality deteriorated afterwards, however, suggesting that a late summer harvest might intercept senescence, and would be more appropriate. Soluble reactive phosphorus (SRP) entering the reservoir in September 1985 was intercepted with alum; apparently, this is the first reported use of alum for SRP removal. The treatment was successful, and 100 percent removal of SRP seems possible with higher alum doses. |
| THE CATTAILS (TYPHA): INTERSPECIFIC ECOLOGICAL DIFFERENCES AND PROBLEMS OF IDENTIFICATION | S. Galen Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 357 - 362 | THE CATTAILS (TYPHA): INTERSPECIFIC ECOLOGICAL DIFFERENCES AND PROBLEMS OF IDENTIFICATION | Accurately identifying the North American cattails (Typha) is important in lake management because Typha is ecologically important and the species differ in ecologically significant ways. Known ecological differences in geographical and ecological range, competitiveness, water-level tolerance, structure and density of shoots, sexual reproduction, and damage by insect parasites are reviewed. Narrow-leaved cattail (T. angustifolia) and hybrid cattail (T. X glauca = T. angustifolia X latifolia) are apparently spreading, often replacing T. latifolia in many disturbed, eutrophic sites in northeastern and north central regions. T. angustifolia and southern cattail (T. domingensis) indicate unstable habitat and nutrient-rich or brackish soil and have more vegetative and flowering shoots per unit area; hybrids suggest habitat disturbance; mixtures of species or seedlings from hybrids may improve success of stands in temporally or spacially variable environments. Ecotypic variation should be considered in choosing sources of propagules. Inaccurate manuals, the importance of microscopic characters, and the common occurrence of hybrids all contribute to the difficulty of identification. A guide to identification of the species and hybrids is provided. |
| DRIFT OF 2,4-D DMA AND CONTROL OF EURASIAN WATERMILFOIL IN LAKE OSOYOOS | Stuart K. Julin; Harry L. Gibbons Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 372 - 376 | DRIFT OF 2,4-D DMA AND CONTROL OF EURASIAN WATERMILFOIL IN LAKE OSOYOOS | The effectiveness of the control on Eurasian watermilfoil (Myriophyllum spicatum) and drift of 2,4-D DMA was determined for two plots in Lake Osoyoos, Wash. Herbicide drift was rapid enough in the case of one test plot to reduce the effectiveness of the 2,4-D DMA applications. In the other test plot less drift of 2,4-D DMA occurred, and good control of Eurasian watermilfoil was achieved. The drift of the herbicide was caused by release of the 2,4-D DMA by the polymer, above water application, improper mixing of 2,4-D DMA with the polymer, and velocity of the water currents. |
| LIMING OF A FINAL CUT ACID LAKE | Greg Knauer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 382 - 385 | LIMING OF A FINAL CUT ACID LAKE | One part of an overall reclamation project for an abandoned strip mine area included neutralizing an acid lake. Other portions of the project included neutralizing acid mine drainage from spoil banks and coal refuse areas in the areas adjacent to the lake. The overall reclamation plan included clay cover, soil amendments, vegetation for all project areas, drainage through a limestone filter to the lake, and neutralization of the acid lake. Laboratory neutralization studies indicated >90,000 kg of lime would be required to neutralize the 4-ha lake which had pH of 2.7 and acidity of 850 mg L-1. Field tests prior to actual liming operations indicated the acidity in the lake had been reduced 50 percent; therefore, liming requirements were reduced correspondingly. The lime was applied by mixing a lime slurry in a hydroseeder apparatus and spraying onto the surface of the lake. The pH values increased form 2.8 to 3.2. One month later a second application of hydrated lime was applied in a similar fashion and pH changed from 3.2 to 3.6 with reduced acidity. Additional laboratory neutralization studies were performed in November 1984; another application of lime increased the lake water pH to 4.8. Results of additional samples collected during August 1985 indicated pH at 6.5, reduced transparency, and chlorophyll a values appearing for the first time. |
| CAPITOL LAKE RESTORATION PROJECT | Ralph D. Nelson; David A. Morency | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 377 - 381 | CAPITOL LAKE RESTORATION PROJECT | Capitol Lake was created by the construction of a roadway fill and tide gate dam structure across the Deschutes River in 1951. The lake, in conjunction with the state capitol, has become a valuable asset to the state of Washington as a tourist attraction, as a recreational area, and as one of Washington's most important anadromous fish-breeding facilities. In 1981, two fishkills were observed near the tide gate dam. Subsequent investigations by the Washington State Department of Ecology identified a deep, chemically stratified depression in Capitol Lake near the tide gate outlet. Marine water was leaking into the lake and settling into the depression (or crater). During certain tidal cycles, the entrapped body of marine water stagnates and toxic hydrogen sulfide gas is formed. Entranco Engineers recently evaluated various alternatives for restoring the tide gate crater and mitigating its adverse impact on water quality. The basic approaches considered were filling in the crater to prevent saltwater entrapment, preventing stratification and stagnation via mixing or aeration, and removing saltwater before stagnation occurs. Saltwater removal by a siphon (with a pump option) was selected. |
| TREATMENT EFFICIENCIES FOR RESIDENTIAL STORMWATER RUNOFF IN A HARDWOOD WETLAND | Harvey H. Harper; Martin P. Wanielista; David M. Baker; Ben M. Fries; Eric H. Livingston | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 351 - 356 | TREATMENT EFFICIENCIES FOR RESIDENTIAL STORMWATER RUNOFF IN A HARDWOOD WETLAND | The fate of nutrients and heavy metals contained in storm-water runoff was investigated in a 3 ha hardwood wetland near Orlando, Fla. The wetland receives stormwater runoff from a large residential community through a small shallow canal and provides treatment prior to discharge to Hidden Lake. Field investigations begun in 1984 were divided into the following tasks: (1) assessing the quantity of nutrients and heavy metals entering the wetland by stormwater runoff, (2) attenuation of the pollutants during travel through the wetland, (3) monitoring movement of nutrients and heavy metals in ground water, and (4) accumulation of nutrients and heavy metals in the sediments of the wetland. During continuous flow, the wetland system was found to be very effective in removing heavy metals but less effective in removing nutrients. Heavy metals appear to be tightly bound into the upper sediment layers. Treatment of runoff by infiltration through wetland soils resulted in good removal of nutrients as well as heavy metals. The results suggest that treatment schemes involving infiltration or retention are possible and more effective than flow-through systems. |
| FISHERIES MANAGEMENT IN LAKE KINNERET (ISRAEL) | Moshe Gophen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 327 - 332 | FISHERIES MANAGEMENT IN LAKE KINNERET (ISRAEL) | Lake Kinneret currently supplies 30-35 percent of Israel's water consumption and is also important as a commercial fishery. In recent years sewage and fish pond waste flow into the lake have been significantly reduced, but benefits from these changes are partially offset by lake fishery management procedures that have decreased water quality. The population of the native planktivorous cichlid Sarotherodon galilaeus is declining, and the stock biomass of the endemic zooplanktivorous bleak, Mirogrex terraesanctae, has increased. This increase, together with the introduction of exotic fish, has negatively affected water quality and interfered with the survival of S. galilaeus fingerlings, mainly during the summer-fall season. The summer phytoplankton populations are dominated by nanoplankton and are mostly controlled by grazing pressure from fish (S. galilaeus) and zooplankton. The most available food source for fish communities in the summer-fall season is zooplankton, which are fed upon intensively because of the high temperatures. These factors underlie an increase in the nanoplankton densities that have affected water quality. Fisheries management recommendations (stocking and commercial fishing) are now aimed at water quality improvement as well as economics. Policies should lower predation pressure from zooplankton in the summer and intensify algal consumption during the winter. Lake ecology, economics, and water quality can be integrated into management plans, yielding benefits in both fisheries and water quality. |
| THE FEEDING ECOLOGY OF THE BLUE TILAPIA (T. AUREA) IN A NORTH CAROLINA RESERVOIR | Michael A. Mallin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 323 - 326 | THE FEEDING ECOLOGY OF THE BLUE TILAPIA (T. AUREA) IN A NORTH CAROLINA RESERVOIR | The blue tilapia (T. aurea) has been introduced at times in the southeast as a biological control agent for nuisance vegetation. The winter and summer food habits of this fish were studied in a heated North Carolina reservoir during 1984. Stomachs from fish captured in February contained mainly organic and inorganic detritus and large amounts of phytoplankton, which was blooming at the time. In August, when plankton was scarce, nearly the entire volume of the stomachs consisted of detritus gleaned from the sediments. The ratio of inorganic to organic material increased along with fish size. Zooplankton and benthic invertebrates comprised only small percentages of the tilapia stomach contents in this reservoir. The data indicate that the blue tilapia is an opportunistic feeder that will successfully utilize whatever food source is available. |
| Public Health Microbiology of Lakes and Reservoirs | George R. Gibson Jr.; Donald L. Johnstone; Dean O. Cliver; Edwin E. Geldreich | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 333 - 336 | Public Health Microbiology of Lakes and Reservoirs | |
| UTILIZATION OF WETLANDS AS BMPs FOR THE REDUCTION OF NITROGEN AND PHOSPHORUS IN AGRICULTURAL RUNOFF FROM SOUTH FLORIDA WATERSHEDS | Alan L. Goldstein | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 345 - 350 | UTILIZATION OF WETLANDS AS BMPs FOR THE REDUCTION OF NITROGEN AND PHOSPHORUS IN AGRICULTURAL RUNOFF FROM SOUTH FLORIDA WATERSHEDS | As part of an overall strategy to evaluate the impacts of river channelization, the Florida legislature funded a three-year demonstration project. Five sites were studied to determine the efficiency and effectiveness of natural and recreated wetlands to reduce nutrient loads in nonpoint source runoff from agricultural lands. The land uses ranged from native range to highly improved pasture and supported cattle populations of various densities, from 1 animal per 20 acres to over 1.5 animals per acre. Typical nutrient loads in nonpoint source runoff from these lands were determined. The abilities of the wetlands to remove nutrients were mixed. Dissolved inorganic forms of nitrogen and phosphorus were consistently actively taken up while particulate-bound forms (mostly organics) were exported in amounts comparable to those measured in the inflows. |
| EXPLORATION OF THE RELATIONSHIPS AMONG ACIDIC DEPOSITION, LAND USE, AND WATER CHEMISTRY | John L. Malanchuk; Gregory J. Mallon; Richard J. Olson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 337 - 343 | EXPLORATION OF THE RELATIONSHIPS AMONG ACIDIC DEPOSITION, LAND USE, AND WATER CHEMISTRY | Many waterzshed characteristics, either by themselves or in combination with acidic deposition, have been shown to influence the acidification of lakes. Correlations and linear regressions were calculated for pairs of watershed characteristics and water chemistry measurements to statistically test, using observational data, these relationships. The study included a subset of 46 headwater lakes in the Adirondack Mountain region of New York State that were common to both the National Surface Water Survey (providing water chemistry data) and the Adirondack Watershed Data Base (providing watershed attribute data). Wet deposition and lake elevation showed strong, negative relationships with both lake pH and alkalinity, although elevation may act as a surrogate variable for other factors, such as soil type, vegetation type, and deposition level. Conifer vegetation, historical fire activity, and wetlands, expressed as the percentage of watershed area, also showed significant, negative relationships with lake pH and alkalinity. Thus, several hypotheses concerning the association of watershed attributes with lake acidification are supported and should be given further consideration in research planning, field surveys, and assessment activities. |
| SHORELINE PROTECTION | Steven McComas; David Jansen; Joe Marter; Don Roseboom | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 421 - 425 | SHORELINE PROTECTION | |
| MANAGING A LOCAL LAKE ASSOCIATION | David Jansen; Thomas U. Gordon; Roy W. Mann | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 418 - 420 | MANAGING A LOCAL LAKE ASSOCIATION | |
| ORGANIZING A LOCAL LAKE MANAGEMENT PROGRAM | Richard S. McVoy; Randolph J. Stowe; William P. O'Connor; Dean Spencer; Bernard Kasierski; Michael Adams; Richard Desoto; Raymond Anderson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 426 - 430 | ORGANIZING A LOCAL LAKE MANAGEMENT PROGRAM | |
| MANAGEMENT IDEAS FOR LAKE HOMEOWNERS | Lowell Klessig; William Jones; George Gibson; Richard L. Hilliker; Stanley Nichols | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 436 - 442 | MANAGEMENT IDEAS FOR LAKE HOMEOWNERS | |
| LAKE SEDIMENT MANAGEMENT WORKSHOP SUMMARY | William W. Jones; Neal O'reilly; Robert Pitt; Richard Wedepohl; Douglas Knauer; Spencer Peterson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 431 - 435 | LAKE SEDIMENT MANAGEMENT WORKSHOP SUMMARY | |
| WORKSHOP SYNOPSIS: ADVANCED CONCEPTS IN LAKE ECOLOGY | Peg Bostwick; Willard Gross; Doug Pullman; Jim D'Antuono | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 415 - 417 | WORKSHOP SYNOPSIS: ADVANCED CONCEPTS IN LAKE ECOLOGY | |
| SOIL SYSTEMS FOR COMMUNITY WASTEWATER DISPOSAL—TREATMENT AND ABSORPTION CASE HISTORIES | E. Jerry Tyler; James C. Converse; Dale E. Parker | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 391 - 396 | SOIL SYSTEMS FOR COMMUNITY WASTEWATER DISPOSAL—TREATMENT AND ABSORPTION CASE HISTORIES | Community subsurface wastewater soil absorption systems in lakeshore developments are to absorb and treat domestic wastewater, protecting public health and the environment. These systems are becoming more common as individual household systems fail, and alternate wastewater disposal methods are needed. Large systems cannot be installed using the same criteria as the individual system unless designed to be narrow, based on hydraulic and pollutant loading. Examples are presented illustrating concepts for siting and designing narrow large wastewater soil absorption systems. |
| MONITORING AND PLANNING FOR ONSITE WASTEWATER DISPOSAL ALONG TVA RESERVOIRS | Frank J. Sagona | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 387 - 390 | MONITORING AND PLANNING FOR ONSITE WASTEWATER DISPOSAL ALONG TVA RESERVOIRS | The Tennessee Valley Authority (TVA) uses various techniques to detect, quantify, and prevent water use impacts from failing septic tank-soil absorption systems (ST-SAS). Low altitude color infrared remote sensing complemented by an in-reservoir leachate detection device are used to locate ST-SAS failures along shoreline residential areas. These detection techniques, followed by a ground-truth survey and/or a water quality sampling program can quantify the severity and type of ST-SAS failures in an area. An onsite wastewater management plan, developed to assess soil suitability for various onsite sewage disposal systems, serves as a guide for proper siting and use of onsite sewage disposal systems along shorelines. Applications of these techniques along selected shorelines of TVA reservoirs are discussed. |
| ALTERNATIVE WASTE SYSTEM TECHNOLOGY FOR LAKE SITE DEVELOPMENTS | B. L. Carlile; D. J. Osborne; C. G. Cogger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 397 - 400 | ALTERNATIVE WASTE SYSTEM TECHNOLOGY FOR LAKE SITE DEVELOPMENTS | Onsite conventional septic tank-soil absorption systems are most often chosen for lakeshore developments when public sewage treatment facilities are not available. This system is chosen because it is simplest and most economical to build; and, when properly designed, installed, and maintained on suitable sites, it provides low-cost wastewater treatment superior to that of most sophisticated secondary treatment plants. Poorly operated septic systems, however, can pollute surface and ground waters and pose a risk to public health in lake site developments. Lake developments, because of site-specific factors such as shallow soils, high water tables, and excessive slopes, may severely limit the conventional gravity-type septic system; such systems often malfunction after a few years' use. Several alternatives have been developed and tested to repair and replace the conventional septic tank system for lake site developments. The major considerations in assessing the suitability of these alternatives were (1) simplicity and reliability—able to operate without the continuous presence of a skilled operator; (2) environmental impact—health, aesthetic, water quality problems minimized; (3) flexibility—capable of operation with changing waste flow; and (4) costs—installation and operational costs less than secondary treatment systems. Several community onsite waste treatment systems meeting these criteria have been developed and installed in lakeshore communities in the south. Special problems dealing with design, installation, and operation of various systems will be discussed. |
| EVALUATION OF PHOSPHORUS LOADING FOR DELAVAN LAKE IN SOUTHEASTERN WISCONSIN | Stephen J. Field | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 408 - 414 | EVALUATION OF PHOSPHORUS LOADING FOR DELAVAN LAKE IN SOUTHEASTERN WISCONSIN | Despite diversion of sewage effluent and septic leachate from Delavan Lake in 1981, dense blue-green algal blooms caused numerous complaints in the summer of 1983. The U.S. Geological Survey started a comprehensive two-year water quality investigation in 1983. All major external inputs and outflows of phosphorus were measured to assess the importance of each source. Internal loads were calculated as a residual of a mass-balance budget. This paper reports the 1984 water year. Although external loads of total phosphorus were sufficient to cause eutrophic conditions, internal loading was 2.6 times the external supply, mostly from summertime anoxic release of phosphorus from lake sediments. Continuous streamflow and water quality monitoring in the subbasins of the Delavan Lake watershed showed a wide range of annual phosphorus yields from 154 kg/km2 in a subbasin of Jackson Creek draining the village of Elkhorn to 50.4 kg/km2 at Jackson Creek's headwaters where the largest concentration of livestock is found. The other major tributary (unnamed) to Delavan Lake had an extremely low phosphorus yield of 10.3 kg/km2 because of significantly reduced runoff from storage and evapotranspiration in a large wetland surrounding a large pond in the stream's basin. |
| PHOSPHORUS EXPORT FROM A LOW-DENSITY RESIDENTIAL WATERSHED AND AN ADJACENT FORESTED WATERSHED | Jeffrey Dennis | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 401 - 407 | PHOSPHORUS EXPORT FROM A LOW-DENSITY RESIDENTIAL WATERSHED AND AN ADJACENT FORESTED WATERSHED | Low density residential subdivisions (< 4.0 units/ha) constitute the majority of new development in Maine's lake watersheds. This study investigates the effect of such development on phosphorus export from adjacent low density residential and forested watersheds. Total phosphorus and discharge measurements were taken of stormwater runoff from a 3.5 ha watershed with uniform, low density residential development. Annual areal phosphorus export from the watershed was 0.44 kg/ha in 1982, a relatively dry year, and greater than 1.5 kg/ha in 1983. In 1983, simultaneous total phosphorus and discharge measurements were taken of stormwater runoff from the residential watershed and an adjacent 2.4 ha forested watershed during eight storm events. For these storm events, the geometric mean of the ratios between developed and forested watersheds for runoff volume was 1.7:1; for peak discharge, 2.6:1; for mean flow-weighted phosphorus concentration, 4.3:1; and for phosphorus export, 7.2:1. |
| OXYGEN DEMAND BY SEDIMENT-GENERATED METHANE | Barry C. Moore; William H. Funk; Kenneth Hartz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 115 - 120 | OXYGEN DEMAND BY SEDIMENT-GENERATED METHANE | Although the contribution of sediment-generated methane to dissolved oxygen demand has been well documented in a number of stratified lakes throughout the world, little work on the subject has been performed in shallow, un-stratified lakes. To quantify the role of methane in carbon and oxygen cycling in such environments, carbon and methane budgets were prepared for Carlisle Lake, a small, shallow, unstratified, hypereutrophic lake. The budgets reveal that about 10 percent of the summer oxygen demand is exerted by the bacterial oxidation of methane. Methane production accounts for recycling of about 5 percent of the carbon produced by primary production and about 10 percent of the carbon reaching the sediments. Methanogenesis may indicate the degree of heterotrophic activity in sediments. This work supports such a conclusion and also suggests that methanogenesis may be indicative of the intensity of nutrient regeneration from sediments. |
| LABORATORY-DETERMINED RATES OF OXYGEN DEMAND AND IRON AND MANGANESE RELEASE FROM SEDIMENTS | Jeffery J. Longaker | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 121 - 125 | LABORATORY-DETERMINED RATES OF OXYGEN DEMAND AND IRON AND MANGANESE RELEASE FROM SEDIMENTS | A technique was developed for determining the sediment oxygen demand (SOD) and iron and manganese release rates under laboratory conditions. Site-specific comparisons of this method with the EPA in situ technique, indicated a consistently lower SOD rate but improved reliability. Manganese release began as the dissolved oxygen concentration approached 1 mg/L and below. Iron release did not begin until -100 to -150 mv oxidation reduction potential was reached. A high degree of consistency was indicated between replicates. Laboratory and in situ SOD rates yielded a two-dimensional model of reservoir oxygen budgets. The laboratory rate compared favorably to the assumed SOD rate of the model. As a result, TVA has incorporated the laboratory-determined rates and iron and manganese release rates into the reservoir management planning process. Specific measured and modeled rates determine waste load allocations for several reservoirs. |
| NUTRIENT WATER QUALITY CRITERIA FOR LAKES IN BRITISH COLUMBIA | Richard N. Nordin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 110 - 113 | NUTRIENT WATER QUALITY CRITERIA FOR LAKES IN BRITISH COLUMBIA | A methodology has been developed to help protect lake water quality from degradation by nutrients. Criteria have been established which are keyed to protect the most sensitive water use of the lake. The categories of water use include aquatic life (including fisheries), recreation and aesthetics, drinking water, agricultural use, and industrial use. These criteria are the basis for more specific water quality objectives that are tailored to individual sites—either lakes or portions of lakes. Phosphorus concentration was chosen as the primary means of quantifying water quality, although nitrogen also can be used where it is the limiting nutrient. For phosphorus-limited lakes, the criteria used to protect drinking water and recreation are 10 μg/L total phosphorus. Criteria for fisheries and aquatic life differ according to important species. For example, for lakes with important salmonid fish resources, the criterion is a phosphorus concentration between 5 and 15 μg/L. For stratified lakes with important warmwater fisheries, a phosphorus concentration of 10-40 μg/L has been proposed. These criteria have been proposed specifically for British Columbia and may not be directly applicable to other areas. |
| A COMPARISON OF RESERVOIR OXYGEN PREDICTIONS FROM ONE-AND TWO-DIMENSIONAL MODELS | James L. Martin; Joseph H. Wlosinski | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 98 - 103 | A COMPARISON OF RESERVOIR OXYGEN PREDICTIONS FROM ONE-AND TWO-DIMENSIONAL MODELS | The U.S. Army Corps of Engineers has developed one-and two-dimensional models as tools for water resources management. CE-QUAL-R1 is a variable-layer, horizontally averaged water quality model. CE-QUAL-W2 is a two-dimensional (laterally averaged) finite-difference hydro-dynamic and transport water quality model. The water quality algorithms in both models are similar and both have been applied to DeGray Lake, Ark., a reservoir that has been extensively studied by the Corps of Engineers. The reservoir is of particular interest because of dissolved oxygen declines in the metalimnion of the main pool during summer and fall months. Both models successfully predict spatial and temporal variations in dissolved oxygen concentrations in their respective dimensions. Evaluations were made of all flux values contributing to simulated oxygen dynamics. |
| CLASSIFICATION OF IOWA LAKES AND THEIR FISH STANDING STOCK | Kay R. Hill | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 105 - 109 | CLASSIFICATION OF IOWA LAKES AND THEIR FISH STANDING STOCK | Using mean basin slope and watershed area to lake surface area ratios, 58 Iowa lakes were classified into four distinct groups. Physical factors that can be altered very little once a lake is constructed may drastically affect sport fishing and the cost of maintaining quality fishing. Mean basin slope () and watershed to lake area ratios (WA) can be determined prior to lake construction, and should ultimately influence lake site and construction plans. The exact relationship between the physical parameters, lake quality, and quality of the fishery in Iowa is unknown. Understanding these relationships will assist in developing fish management programs for existing lakes and describing the fisheries potential of proposed lakes. The lake groups formed used the following criteria: Group A, WA 0/-30:1 and greater than 8 percent; Group B, WA 30/-80:1 and greater than 4 percent; Group C, WA 0/-30:1 and below 8 percent; Group D, WA greater than 40:1 and below 8 percent. A lake with WA greater than 80:1 or with below 2 percent would also be classified as Group D. Angler acceptable standing stock was composed of bluegill, Lepomis macrochirus, and redear sunfish, Lepomis microlophus, TL 152 mm (6 in.) or larger; crappie, Pomoxis sp., TL 203 mm (8 in.) or larger, largemouth bass, Micropterus salmoides, TL 254 mm (10 in.) or larger, channel catfish, Ictalurus punctatus, TL 305 mm (12 in.) or larger, and black bullhead, Ictalurus melas, TL 203 mm (8 in.) or larger. Mean standing of fish varied among lake groups, ranging from 652 kg/ha (583 lbs/acre) to 808 g/ha (722 lbs/acre). Mean standing stock acceptable to anglers was 309 kg/ha (276 lbs/acre) in Group A lakes, 464 kg/ha (415 lbs/acre) in Group B lakes, 478 kg/ha (427 lbs/acre) in Group C lakes, and 132 kg/ha (118 lbs/acre) in Group D lakes. Statistical analysis revealed that mean standing stock of angler acceptable fish was significantly greater in Groups A and B lakes than in Group D. Group B lakes produced a significantly higher mean standing stock of angler acceptable fish than Group A. These data suggest that lakes with basin and watershed characteristics similar to those in Group B produce maximum angler acceptable fish standing stocks. |
| THE INFLUENCE OF LAKE AND BASIN MORPHOLOGY ON INTERNAL PHOSPHORUS LOADING IN SOFTWATER LAKES | Colin J. P. McKean | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 126 - 130 | THE INFLUENCE OF LAKE AND BASIN MORPHOLOGY ON INTERNAL PHOSPHORUS LOADING IN SOFTWATER LAKES | Twenty-three softwater lakes in British Columbia, Canada, were sampled before fall overturn to assess the in situ conditions associated with internal phosphorus loading. Hypolimnetic sediment and water results were correlated with physical and morphological characteristics of each lake. The concentration of soluble reactive phosphorus (SRP) measured 1 m above the sediment-water interface was strongly correlated with the oxidation reduction potential (ORP) measured at the same depth. Above 0 mV, soluble reactive phosphorus was below 3 μgL-1 at 1 m above the sediment-water interface. Below 0 mV, soluble reactive phosphorus concentrations increased exponentially with decreasing oxidation reduction potential. A model using sediment loss on ignition (LOI) and spring overturn phosphorus (SOP) can predict the hypolimnetic oxidation reduction potential. Lakes with areal water loading values < 10 m yr-1 typically had higher loss on ignition and spring overturn phosphorus concentrations. High loss on ignition and spring overturn phosphorus concentrations will cause anoxic conditions in the hypolimnion and internal phosphorus loading if the oxidation reduction potential drops below 0 mV at the sediment-water interface. Using the relationships presented, the impact of watershed development and lake restoration projects on internal phosphorus loading can be predicted. |
| A STOCHASTIC ADAPTATION OF THE VOLLENWEIDER PHOSPHORUS MODEL | Daniel G. Burden; Ronald F. Malone; Constantine E. Mericas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 149 - 153 | A STOCHASTIC ADAPTATION OF THE VOLLENWEIDER PHOSPHORUS MODEL | A stochastic modification of the basic Vollenweider model was used to represent variability in daily phosphorus concentrations in a small southern hypereutrophic lake. Uncertainty measurements, arising from defining initial conditions such as loading estimates, and a lumped white-noise parameter were used to project probability distributions of mean daily in-lake phosphorus concentrations. Additional consideration of spatial variability permitted comparison of model projections with monitoring data. Model calibration was performed with over 500 temporally and spatially distributed total phosphorus observations, ranging from 0.171 to 1.575 mg/L, taken from a 70-day intensive monitoring program in 1983. Results indicate the model's potential usefulness, particularly in unstable systems, although short-term oxygen depression, stratification, and catastrophic events, such as a 12.7 cm rainstorm, limited its predictive capabilities. |
| EMPIRICAL BAYES ESTIMATION AND INFERENCE FOR THE PHOSPHORUS–CHLOROPHYLL RELATIONSHIP IN LAKES | Kenneth H. Reckhow; Carlos M. Marin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 154 - 156 | EMPIRICAL BAYES ESTIMATION AND INFERENCE FOR THE PHOSPHORUS-CHLOROPHYLL RELATIONSHIP IN LAKES | State and regional agencies frequently must use a model or models to assess limnological relationships, like that between phosphorus and chlorophyll, in a large number of lakes. If lake behavior in all lakes is essentially identical, then it is reasonable to pool information across lakes concerning the relationships and to make inferences on the basis of a universal model. Alternatively, if all lakes are unique, then inferences must be drawn from lake-specific models. The truth probably lies somewhere in between these two extremes. On that basis, empirical Bayes estimation is used to fit a simple model relating phosphorus to chlorophyll in lakes. The model is then applied to each lake in such a way that the chlorophyll prediction is based on both lake-specific and regional lake information. For lakes as a whole, the empirical Bayes estimator should result in improved predictions over standard approaches. |
| MODELS AND SOFTWARE FOR RESERVOIR EUTROPHICATION ASSESSMENT | William W. Walker Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 143 - 148 | MODELS AND SOFTWARE FOR RESERVOIR EUTROPHICATION ASSESSMENT | Eutrophication has several direct and indirect effects on reservoir water quality and uses. The paper describes assessment procedures recently developed for application to Corps of Engineer reservoirs. Study phases include problem identification, data gathering, data reduction, and model implementation. Three interactive computer programs (FLUX, PROFILE, BATHTUB) assist in the last two phases. Eutrophication-related water quality conditions (expressed in total phosphorus, total nitrogen, particulate phosphorus, and hypolimnetic oxygen depletion rate) are predicted using empirical relationships calibrated and tested for reservoir applications. Based upon research using several independent data sets, previous “northern-lake-based†empirical modeling approaches have been modified to account for effects of (1) nonlinear nutrient sedimentation kinetics; (2) algal growth limitation by phosphorus, nitrogen, light, and flushing rate; (3) inflow nutrient partitioning (bioavailability of dissolved versus particulate loadings); (4) seasonal variations in loadings and morphometry; and (5) spatial variations in nutrients and related trophic-state indicators. To reflect input data limitations and inherent model errors, inputs and outputs can abe expressed in probabilistic terms. The segmented model can be applied to single reservoirs (mixed or spatially segmented), networks of reservoirs (hydrologically linked), or collections of reservoirs (hydrologically independent). The last type of application permits regional comparisons of reservoir conditions, controlling factors, and model performance. |
| WATER QUALITY IN LONG LAKE, MINNESOTA, FOLLOWING RIPLOX SEDIMENT TREATMENT | Terry A. Noonan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 131 - 137 | WATER QUALITY IN LONG LAKE, MINNESOTA, FOLLOWING RIPLOX SEDIMENT TREATMENT | The water quality of the south basin of Long Lake, Minn. was monitored following Ca(NO3)2 application in May 1984. The NO2+ NO3-N concentration was elevated throughout the water column in 1984, but declined to pretreatment levels by 1985. Growing season mean total phosphorus and chlorophyll a concentrations were similar to pretreatment years. The impact of sediment Ca(NO3)2 treatment on midsummer water quality in Long Lake was slight because of external loading. Sediment composition and residual NO3-N may limit the usefulness of this technique in many lakes. |
| INTERNAL PHOSPHORUS RECYCLING MECHANISMS IN SHALLOW LAKES | W. Ripl | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 138 - 142 | INTERNAL PHOSPHORUS RECYCLING MECHANISMS IN SHALLOW LAKES | Budget calculations in the shallow lakes Dmmer and Schlei, F.R.G., and in limnocorral experiments carried out in Lake Schlei between 1981 and 1983 showed large seasonal fluctuations of internal phosphorus loading. These fluctuations were related to the load of the electron acceptors nitrate and sulfate from the tributaries and the internal metabolic processes. Based on lake budget studies, phosphorus release occurs predominantly during late spring and early summer (two months with maximum release rates of up to 200 mgP/m2·d). In situ release rates correlated poorly with water column pH and with results of laboratory experiments carried out on those sediments. The phosphorus released was correlated with iron-bound phosphorus in the sediment (phosphorus measured as extractable by hydrogen sulfate treatment); however, down to a depth of microbial activation in the sediment. Algal development and nitrate depletion in the water had a strong triggering effect on phosphorus release from sediment. The mechanisms of internal phosphorus recycling became evident by monitoring the concentrations of iron, phosphorus, sulfate, and nitrate in the interstitial solutions. Management implications were derived from these results. |
| BIOLOGICAL MANAGEMENT OF A POND ECOSYSTEM TO MEET WATER USE OBJECTIVES | Kenneth J. Wagner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 54 - 59 | BIOLOGICAL MANAGEMENT OF A POND ECOSYSTEM TO MEET WATER USE OBJECTIVES | The biological structure of a 1.4 ha (3.5 acre) pond in Oldwick, N.J., was assessed during 1983 to facilitate improving swimming and fishing conditions. A biological management strategy, including reducing planktivore populations and restructuring of fish community size distribution, was employed in the spring of 1984. Although fish biomass was reduced, proportional stock density values indicated that fishing quality was substantially improved. Growth and recruitment of gamefish appeared to be minimally affected after one year of post-implementation monitoring. Reduced adult planktivore biomass lessened predation pressure on zooplankton stocks, which increased in both abundance and mean individual size. A resultant increase in grazing activity yielded reduced phytoplankton biomass through the summer and increased water clarity. Appeal and safety for contact recreation were noticably enhanced. The results suggest that managing fish populations can have cascading effects on other trophic levels to achieve a balance among desired water uses. |
| THE USE OF DIVERSION, EXCAVATION, AND GROUNDWATER DILUTION TO RESTORE DELAWARE PARK LAKE, BUFFALO, NEW YORK | Gerald F. Mikol; Jay A. Bloomfield; Paul Erickson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 61 - 63 | THE USE OF DIVERSION, EXCAVATION, AND GROUNDWATER DILUTION TO RESTORE DELAWARE PARK LAKE, BUFFALO, NEW YORK | Delaware Park Lake is an 11 ha lake located in Buffalo, N.Y. The average depth of the lake in 1975 was approximately 1.0 m. The lake suffered from eutrophication and associated problems including algal blooms, fishkills, odor, high turbidity, and bacterial contamination. In 1976 a four-part project to restore the lake was proposed under the federal Clean Lakes Program. The plan included isolating the lake from its inlet and outlet and diverting the inlet stream around the lake. The second project element rerouted storm sewers that had been entering the lake. The third involved involved draining and dry excavating 100,000 m3 of bottom sediments. The final phase provided a makeup source and dilution water by way of a groundwater pumping system. Pre-restoration (April-August, 1979) water quality parameters indicated degraded conditions. Total phosphorus, chlorophyll a, and Secchi transparency averaged 120 μg/L, 19.3 μg/L and 0.6 meter, respectively. Post-restoration quality (May-August, 1984) is improved with total phosphorus, chlorophyll a, and Secchi transparency averaging 26 μg/L, 8.2 μg/L and 1.0 meter, respectively. |
| THE ROLE OF BIOMANIPULATION IN FISHERIES MANAGEMENT | William W. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 49 - 53 | THE ROLE OF BIOMANIPULATION IN FISHERIES MANAGEMENT | Biomanipulation is a relatively new approach toward managing lakes. As a result, few data support its use, and many fisheries managers are reluctant to apply this technology. However, the results of biomanipulation and fisheries renovation programs are often the same: reduced populations of nuisance algae and improved water transparency. In this paper, the relative roles of rough fish elimination and restructuring the plankton-fish mix (biomanipulation) are compared as mechanisms in improving water transparency in lakes. Fisheries survey records from 13 renovated or winterkilled Indiana lakes are used to quantify these relationships. A statistically significant inverse relationship between Secchi disk transparency and percent of planktivorous fish exists for the lakes studied. Possible mechanisms for change are discussed, and recommendations for fisheries management are advanced. |
| CONTROL OF SUBMERGED AQUATIC PLANTS WITH TRIPLOID GRASS CARP IN SOUTHERN CALIFORNIA IRRIGATION CANALS | Randall K. Stocker; Neal T. Hagstrom | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 41 - 45 | CONTROL OF SUBMERGED AQUATIC PLANTS WITH TRIPLOID GRASS CARP IN SOUTHERN CALIFORNIA IRRIGATION CANALS | During June 1985 triploid grass carp (Ctenopharyngodon idella Vl.) were stocked in a large canal (2,000 cfs) to evaluate their potential for controlling hydrilla (Hydrilla verticillata L.F. Royle). Hydrilla biomass decreased from 9.1 kg/m2 at the time of stocking to 0.12 kg/m2 at the end of six weeks (includes effects of partial drawdown). Larger radio-tagged fish (1,000 g) had negotiated smaller canal culverts and siphons in previous studies, but the smaller fish of this stocking (120 g) have not traveled upstream past any structures with an elevation drop or turbulence. A canal drawdown one week after stocking removed aboveground biomass of plants in shallow water, but the reappearance of small plants in this area may indicate that the fish are less willing to feed in shallow water. Fish should be stocked between structures and at frequent intervals on long reaches of uninterrupted canal. Stocking prior to plant biomass buildup allows faster weed control. |
| CONSIDERATIONS FOR THE USE OF GRASS CARP IN LARGE, OPEN SYSTEMS | Richard L. Noble; Phillip W. Bettoli; Robert K. Betsill | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 46 - 48 | CONSIDERATIONS FOR THE USE OF GRASS CARP IN LARGE, OPEN SYSTEMS | Grass carp have effectively controlled submergent aquatic macrophytes in large reservoirs when stocked at densities up to 75 fish per vegetated hectare. Large systems pose special concerns relative to decisions on whether to stock grass carp. Multiple use, multiple agency involvement, and interstate jurisdictions complicate decisionmaking. Complex vegetation communities of large systems make results less predictable. Grass carp movements not only allow impacts on nontarget areas but also may result in incomplete control. Grass carp biology is understood well enough to predict effects on vegetation, but vegetation responses to grass carp are not predictable enough for vegetation to be managed rather than controlled. This paper discusses the potentials and limitations for grass carp in large, open systems based principally upon studies in Lake Conroe, Tex., where 45 percent of the 8,000-hectare reservoir was infested by submergent macrophytes. |
| THE SPREAD OF EURASIAN WATERMILFOIL MYRIOPHYLLUM SPICATUM IN DEVILS LAKE, SAUK COUNTY, WISCONSIN | Richard A. Lillie | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 64 - 68 | THE SPREAD OF EURASIAN WATERMILFOIL MYRIOPHYLLUM SPICATUM IN DEVILS LAKE, SAUK COUNTY, WISCONSIN | A quantitative survey of the submersed aquatic macrophytes of Devils Lake, a 151 ha softwater seepage lake, was conducted July 30-August 1, 1984, in an effort to assess historical changes in the lake's macrophytes and water quality. Biomass (oven dry weight) and frequency of occurrence data were obtained from 28 transects spaced 200 m apart. Sample quadrats of 0.1 m2 were collected at 5 m intervals along transects from shore to a water depth of 9 m. Eurasian watermilfoil, Myriophyllum spicatum, ranked second only to Potamogeton robbinsii in importance, comprising 21 percent of total biomass and 35 percent frequency of occurrence. Milfoil was visually dominant, forming three distinctive surface canopy beds 25-50 m wide by 300 m long at water depths from 2-3 m. Total milfoil acreage (3 ha) represented 10 percent of the total vegetational cover in the lake. Average milfoil biomass within dense stands ranged from 160 to 183 g/m2 between beds. Milfoil expansion within Devils Lake was accompanied by a decline in Elodea canadensis. M. spicatum may be a disturbance indicator species (pioneer) rather than an aggressive invader. |
| COUPLING A ONE-DIMENSIONAL MODEL FOR SIMULATING RUN–OF–THE–RIVER RESERVOIRS | Dennis D. Holme; James W. Bakke; Joseph H. Wlosinski | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 87 - 91 | COUPLING A ONE-DIMENSIONAL MODEL FOR SIMULATING RUN-OF-THE-RIVER RESERVOIRS | A mathematical model of Lake Ashtabula Reservoir, Valley City, N. Dak., was developed based on the one-dimensional reservoir thermal model, CE-THERM-R1. The major assumption employed in CE-THERM-R1 is that the reservoir is represented as a vertical series of completely mixed horizontal layers (one-dimensional assumption). Longitudinal and lateral variations of constituent concentrations cannot be predicted. Lake Ashtabula, whose pool is long, narrow and largely confined to the run-of-the-river, exhibits both vertical and longitudinal water quality gradients. To represent this two-dimensional aspect of the system, the model was organized using three CE-THERM-R1 pools coupled in series in which the simulated outflow constituent quantities for the first and second pools became the inflows for their respective downstream pools. By using this model configuration it was possible to simulate longitudinal as well as vertical temperature variation and the concentration of total dissolved solids, thus reducing the severity of the one-dimensional assumption. |
| THE USE OF CE-THERM-R1 AND REAL-TIME METEOROLOGICAL DATA FOR THE PREDICTION OF NONSEASONAL MIXING: THE DEVELOPMENT OF EVENT-RELATED SAMPLING | James E. Schindler; Carroll L. Missimer; Stephen P. Schreiner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 93 - 97 | THE USE OF CE-THERM-R1 AND REAL-TIME METEOROLOGICAL DATA FOR THE PREDICTION OF NONSEASONAL MIXING: THE DEVELOPMENT OF EVENT-RELATED SAMPLING | The CE-THERM-R1 model was used to simulate the depths of mixing and frequencies of short-term, non-seasonal hydrodynamic behaviors for a small (1.5 ha) pond in western South Carolina. Two years of data were used to calibrate the system coefficients and to assess the adequacy of the simulations. Mixing depths and frequencies were then used to assess the effects of nonseasonal allogenic forces on the planktonic succession and distribution. The results demonstrate that the intensities and frequencies of allogenic forces are directly related to the plankton periodicity and the development and persistence of accumulations of organisms and particulate material. The calibrated model is now being tested for predictions of system responses to real-time meteorological data collected from a local meteorological tower. |
| PHRED: A MICROCOMPUTER PROGRAM TO ASSESS NONPOINT POLLUTION FROM EROSION ON CROPLAND AND TO SELECT REMEDIAL BEST MANAGEMENT PRACTICES THROUGH INCREMENTAL ANALYSIS ON A FIELD BY FIELD BASIS | C. S. Knight | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 79 - 86 | PHRED: A MICROCOMPUTER PROGRAM TO ASSESS NONPOINT POLLUTION FROM EROSION ON CROPLAND AND TO SELECT REMEDIAL BEST MANAGEMENT PRACTICES THROUGH INCREMENTAL ANALYSIS ON A FIELD BY FIELD BASIS | PHRED is a computer program written in C to run on the Radio Shack Tandy 6000 microcomputer. This program quantifies nonpoint source pollution in the form of sediment and phosphorus from cropland that is either in rotation or in continuous corn. It computes the production cost and net return to the farmer for existing conditions and for combinations of management practices. It also derives the corresponding dollar value benefit of pollutant reduction for each of the possible conservation practices and determines a benefit-to-cost ratio (B/C ratio). Conservation practices are incrementally applied to fields with excessive erosion rates in order of best B/C ratio until either an overall B/C ratio of 1 or an allowable erosion rate is achieved. Printouts of erosion rates, sediment delivery, phosphorus delivery, on and off site benefits, production costs, net returns, and conservation practices are available on a field by field basis and as aggregated totals for the farm and/or watershed. |
| THE EFFECTS OF WINTER DRAWDOWN ON MACROPHYTES IN CANDLEWOOD LAKE, CONNECTICUT | Peter A. Siver; A. Michael Coleman; George A. Benson; Jonathan T. Simpson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 69 - 73 | THE EFFECTS OF WINTER DRAWDOWN ON MACROPHYTES IN CANDLEWOOD LAKE, CONNECTICUT | Between 1980 and 1983 dense beds of the macrophyte Myriophyllum spicatum L. became well established throughout Candlewood Lake, Conn., at the expense of a once diverse native flora. During 1983-84 and 1984-85 winter drawdowns of 2 and 2.7 m, respectively, were attempted to control the densities and further spread of the M. spicatum. After the initial drawdown, weed biomass was reduced by more than 90 percent in shallow sites; however, little change in densities occurred in deeper areas. The deeper drawdown resulted in a further reduction in M. spicatum densities, although it remained the dominant plant at depths greater than 2.5 m. Najas minor allioni became the dominant macrophyte in shallow areas, presumably developing from seeds. |
| A MICROCOMPUTER PROGRAM FOR SELECTING AND OPTIMIZING ACID LAKE RENOVATION TECHNIQUES | Paul W. Rodgers; J. V. DePinto; D. L. Britt; W. P. Saunders; H. U. Sverdrup; P. G. Warfvinge | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 75 - 78 | A MICROCOMPUTER PROGRAM FOR SELECTING AND OPTIMIZING ACID LAKE RENOVATION TECHNIQUES | In support of the U.S. Fish and Wildlife Service's Acid Precipitation Mitigation Program, International Science & Technology, Inc., and its subcontractors, AquaComp, Inc. and Svenska IS&T, developed a microcomputer-based decision model to assist water resource managers in selecting the most effective chemical neutralization strategy for renovating acid-stressed lakes and streams. The program can be used to establish proper dosages for a neutralization agent such as aglime through a dose calculation/dissolution subroutine. In addition, the program can assist in the selection of the most appropriate chemical agent, grain size (for neutralization agent), application technique, and reapplication rates to optimize costs and effectiveness for treating a particular system. The program also has subroutines that address dose calculations and effectiveness in meeting water quality objectives. |
| A SIMPLIFIED METHOD FOR OBTAINING MONITORED PHOSPHORUS LOADINGS | Richard C. Lathrop | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 20 - 26 | A SIMPLIFIED METHOD FOR OBTAINING MONITORED PHOSPHORUS LOADINGS | A method for computing phosphorus loadings from continuous stream discharge records and discrete water samples is presented. Because of the highly variable relationship between phosphorus concentrations and runoff discharges, loadings for runoff events with incomplete or no concentration data become difficult to compute. However, concentrations can be predicted from instantaneous discharge data using simple linear regression after separating the phosphorus data into the dissolved and particulate components. Dissolved phosphorus is stratified according to season when the ground is either frozen or not. Particulate phosphorus, because of its strong correlation to suspended sediment, is stratified according to the “event intensity†as determined by rainfall intensity and rate of rise of the stream hydrograph. The particulate data can be further stratified according to whether the sample was taken on the rise or fall (including peak) of the hydrograph. Field sampling recommendations are made based on the study findings. |
| A COMPARISON OF WATER QUALITY IN CHAUTAUQUA LAKE, NEW YORK: 1937–1983 | Thomas A. Storch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 15 - 19 | A COMPARISON OF WATER QUALITY IN CHAUTAUQUA LAKE, NEW YORK: 1937-1983 | Limnological studies undertaken on Chautauqua Lake, N.Y., between 1974 and 1983 indicated that lake water quality can be assessed by monitoring Secchi disk transparency and phytoplankton chlorophyll a. These measurements of phytoplankton abundance were observed to vary from year to year depending on the amount of precipitation; high chlorophyll a and poor transparency correlated with high precipitation, presumably due to increased loading of nutrients to the lake. Comparison of the data collected between 1974 and 1983 with comparable measurements made in the 1930s revealed that Chautauqua Lake water quality has not been substantially altered over the last 50 years. Transparency and the occurrence of blue-green algae were similar, although diatoms may have been more abundant in the 1930s. The results of these limnological studies reinforce the concept that long-term monitoring of algal abundance and species composition can be an appropriate means of detecting changes in lake water quality. |
| TECHNICAL AND POLICY ISSUES ASSOCIATED WITH MONITORING CHEMICALLY CONTAMINATED GROUNDWATER INPUT TO ANNABESSACOOK LAKE, MAINE | Debra J. Miller; Thomas U. Gordon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 27 - 32 | TECHNICAL AND POLICY ISSUES ASSOCIATED WITH MONITORING CHEMICALLY CONTAMINATED GROUNDWATER INPUT TO ANNABESSACOOK LAKE, MAINE | Public desires to fully understand the extent of hazardous waste contamination conflict with the reality of limited resources for data collection. Movement of groundwater plumes contaminated with organic chemicals from a landfill area toward Annabessacook Lake were documented in an EPA Remedial Investigation, but proof that chemicals had reached the lake remains elusive. Data deficiencies identified by Cobbossee Watershed District have produced monitoring refinements with more definitive results. EPA is presently selecting a cleanup strategy. Proposed massive expenditures for comprehensive cleanup activities cannot be justified on the basis of the limited lake data collected. Local and state agencies have made the unusual recommendation to delay immediate cleanup until further monitoring quantifies the problem. A phased cleanup approach has been proposed which would use monitoring in conjunction with negotiated “action levels†to initiate cleanup options. Final decisions by government and private interests are anticipated this year. |
| POLYCHLORINATED BIPHENYL CONTAMINATION OF FORT LOUDOUN RESERVOIR: A MANAGEMENT RESPONSE TO THE FOOD AND DRUG ADMINISTRATION 1984 REVISION OF LIMITS FOR PCB IN FISH FLESH | Neil E. Carriker; A. David McKinney | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 38 - 40 | POLYCHLORINATED BIPHENYL CONTAMINATION OF FORT LOUDOUN RESERVOIR: A MANAGEMENT RESPONSE TO THE FOOD AND DRUG ADMINISTRATION 1984 REVISION OF LIMITS FOR PCB IN FISH FLESH | The Tennessee Division of Water Pollution Control and the Tennessee Valley Authority (TVA) conducted a series of investigations from 1981 through 1983 to determine the extent of polychlorinated biphenyl (PCB) contamination of fish and sediment in Fort Loudoun Reservoir near Knoxville, Tenn. Fish and sediments from the Little River embayment had higher PCB concentrations than samples from other parts of the reservoir, and sediments contained up to 7 μg/g PCB near the mouth of the embayment. Little River embayment catfish contained up to 22 μg/g PCB in edible flesh, and over 60 percent exceeded the 5 μg/g Food and Drug Administration (FDA) limit for PCB. Sport fish and commercially important rough fish had PCB burdens below the 5 μg/g FDA limit. As a management response, a public advisory in April 1982 recommended against frequent consumption of catfish from Fort Loudoun Reservoir or consumption of any catfish from the Little River embayment. The Little River embayment was posted and closed to commercial catfishing. Active sources of PCB contamination were identified and eliminated. In August 1984 FDA revised the limit for PCB in edible fish flesh from 5 μg/g to 2 μg/g. As a public health precaution, Fort Loudoun Reservoir was closed to the taking of catfish for commercial resale and a public health advisory was issued against consumption of catfish by sport fishers. An extensive sampling program was designed and initiated to update the 1981-83 data base. |
| MERCURY LEVELS IN NORTHERN PIKE, ESOX LUCIUS, RELATIVE TO WATER CHEMISTRY IN NORTHERN MINNEOSTA LAKES | Steven A. Heiskary; Daniel D. Helwig | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 33 - 37 | MERCURY LEVELS IN NORTHERN PIKE, ESOX LUCIUS, RELATIVE TO WATER CHEMISTRY IN NORTHERN MINNEOSTA LAKES | Previous studies on lakes in northern Minnesota revealed elevated fish mercury concentrations. These results prompted fish consumption advisories on several lakes. As a followup to that work, fish fillet samples were collected for mercury analysis from 98 lakes in northern Minnesota from 1981 through 1983. Northern pike (Esox lucius) was picked as an indicator species because of its distribution throughout the region. Mercury concentrations ranged from 0.10 μg/g to 2.72 μg/g. This paper will focus on the relationship between the water chemistry of these lakes and the mercury concentration in a single size class of northern pike (50-63 cm). Correlation analysis (Spearman) revealed significant positive correlations between fish mercury and water measurements of aluminum and color and significant negative correlations between fish mercury and pH, alkalinity, and calcium. A multiregression procedure (SAS RSQUARE) revealed that the best multivariate model for predicting fish mercury concentrations, for this data set, included water aluminum, pH, and trophic status (expressed in terms of Carlson's TSI). This model will be used to identify lakes in Minnesota where future fish mercury studies should be focused. |
| EFFECTIVE LOW-COST AREAWIDE WATER QUALITY MONITORING | Richard C. Albert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 11 - 14 | EFFECTIVE LOW-COST AREAWIDE WATER QUALITY MONITORING | In 1984 the Delaware River Basin Commission and the National Park Service began a monitoring program to increase the frequency and areal extent of sampling within existing budget limitations. The goal of the program is to obtain water quality information on 120 miles of the Delaware River and 75 tributaries in a three-state area. This reach is included in the National Wild and Scenic Rivers System; recreation is intense. A variety of real and potential pollution sources exist. To maximize the available resources, a water quality screening approach was developed and put into practice via informal interagency cooperation. Parameters include rainfall, fecal bacteria, benthos diversity, and several chemical parameters. These are analyzed separately and compared between parameters and with adjacent watersheds. Experience has shown that the screening approach effectively assesses problems, sources of problems, and water quality management priorities. Small-scale research is also conducted and a feedback mechanism allows the program to adjust quickly to findings. The water quality screening approach applies to a variety of watershed and lake management situations and can augment traditional routine monitoring programs. |
| CLEAN WATER: A JOINT VENTURE | Peter C. Myers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 4 - 6 | CLEAN WATER: A JOINT VENTURE | |
| THE PAST—AND THE FUTURE—FOR EPA | Lawrence J. Jensen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 1 - 3 | THE PAST—AND THE FUTURE—FOR EPA | |
| LAKE MANAGEMENT: THE ECOSYSTEM APPROACH | Douglas J. La Follette | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 7 - 8 | LAKE MANAGEMENT: THE ECOSYSTEM APPROACH | |
| MULTIPLE PERSPECTIVES ON THE NEED FOR QUALITY LAKES | Walt Peechatka | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 10 | MULTIPLE PERSPECTIVES ON THE NEED FOR QUALITY LAKES | |
| MULTIDISCIPLINARY PERSPECTIVES ON THE NEED FOR QUALITY LAKES | Gene Honn | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 9 | MULTIDISCIPLINARY PERSPECTIVES ON THE NEED FOR QUALITY LAKES | |
| PHOSPHORUS CRITERIA AND WATER QUALITY MANAGEMENT FOR AGRICULTURAL WATERSHEDS | A. N. Sharpley; S. J. Smith; R. G. Menzel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 177 - 182 | PHOSPHORUS CRITERIA AND WATER QUALITY MANAGEMENT FOR AGRICULTURAL WATERSHEDS | The concentrations and amounts of soluble and total phosphorus in rainfall, runoff, impoundments, and stream flow from several unfertilized watersheds in the Southern Plains have been monitored for the past decade to assess the effects of varying land uses on water quality as indicated by phosphorus concentration. Mean annual soluble and total phosphorus concentrations of 12 and 25 μg L-1 were observed in rainfall, 199 and 710 μg L-1 in runoff from unfertilized grassland, and 165 and 1,875 μg L-1 from unfertilized cropland. Soluble phosphorus from rainfall averaged 41 g ha-1, while that exported in runoff averaged 119 and 82 g ha-1 yr-1 for grassland and cropland watersheds, respectively. The load enrichment of phosphorus in runoff compared to rainfall was related to the water soluble phosphorus content of surface soil for each watershed (r2 = 0.96 to 0.99). Soluble and total phosphorus concentrations in rainfall, runoff, and stream flow were sufficient to stimulate accelerated eutrophication according to critical phosphorus concentration guidelines. These guidelines — 10 and 20 μg L-1 for soluble and total phosphorus, respectively—have been slightly modified by states for stream flow criteria. Data on phosphorus concentrations in rainfall and runoff from unfertilized watersheds at other U.S. and overseas locations are similarly above critical values; therefore, best management practices may not lower phosphorus concentrations on cultivated or grazed land to the critical values in runoff or stream flow. Management practices aimed at reducing nonpoint source phosphorus loading should be focused for areas where soil phosphorus levels have been raised above natural levels by applying fertilizers, manure, or crop residues. |
| INSTREAM FLOW REQUIREMENTS BELOW RESERVOIRS: CONCLUSIONS FROM THE EPRI STUDY | J. Emil Morhardt; E. Altouney | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 183 - 186 | INSTREAM FLOW REQUIREMENTS BELOW RESERVOIRS: CONCLUSIONS FROM THE EPRI STUDY | The Electric Power Research Institute (EPRI) is completing a review of methods used or useful for recommending instream flows below reservoirs. The three principal conclusions: no consensus exists on the number or identity of input variables needed to model the biological effects of flow alteration; although mechanistic models predicting the biological effects of flow alterations would be highly desirable, none yet exists; and, the only models that seem geographically transportable are ones that select site-specific input variables, use site-specific data transformation schemes, or adjust parameters to correspond to regional characteristics. The existing methods are equally represented by those recommending a particular flow regime from only basin or hydraulic variables without clear justification; those producing a relationship between flow and an unmeasurable habitat index (such as the U.S. Fish and Wildlife Service Habitat Suitability Indexes or Weighted Usable Area); and those producing an empirically descriptive (but not usually predictive) equation relating flow to standing crop of fish, invertebrates, or riparian vegetation. This paper discusses the results of the EPRI study and suggests future approaches to making instream flow recommendations. |
| NONPOINT POLLUTION CONTROL STRATEGIES FOR MOSES LAKE, WASHINGTON | Richard C. Bain Jr.; Richard R. Horner; Leigh Nelson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 170 - 176 | NONPOINT POLLUTION CONTROL STRATEGIES FOR MOSES LAKE, WASHINGTON | Nutrient sources influencing eutrophication of Moses Lake, Wash., have been evaluated in a multistage investigation of urban and agricultural land uses in the watershed. Nutrient loadings from surface and groundwater contributions were quantified in a year-long monitoring program. Subsequent studies have assessed effectiveness of various control techniques to reduce nutrient input to the lake. These recent (1984) investigations include full-scale field demonstrations of agricultural irrigation practices involving cablegation, wheel line, and center pivot systems monitoring nutrient and water movement through coarse native soils. Over 75 percent of local farmers are trying control measures under a unique agricultural cost-sharing program. Other nutrient sources and controls evaluated and ranked for nutrient removal effectiveness include shallow detention ponds to enhance nutrient trapping, local septic tank management policies, animal waste and fish hatchery controls, and miscellaneous in-lake improvements affecting circulation, water depth, and macrophyte harvesting. This paper describes the proposed control strategies and the prioritizing system used to implement and fund them. |
| EVALUATION OF WASTEWATER PHOSPHORUS SOURCE CONTROLS IN FLATHEAD LAKE BASIN, MONTANA | Damann L. Anderson; Richard J. Otis | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 157 - 164 | EVALUATION OF WASTEWATER PHOSPHORUS SOURCE CONTROLS IN FLATHEAD LAKE BASIN, MONTANA | Recent studies of Flathead Lake, the largest freshwater lake in the western United States, suggest that it may be experiencing the effects of nutrient enrichment. Two measures to control the amount of phosphorus entering the lake from wastewater sources have been suggested to help alleviate this change. One measure instituted in the fall of 1983 was to limit the effluent concentrations from the treatment plants in the basin to 1 mg/L total phosphorus. Plants are to be on line by November 1986. In the interim, a phosphorus detergent ban is under consideration as a second control measure. This study was undertaken to assess alternative interim wastewater control measures. It was estimated that effluent limitations on the municipal plants could reduce the wastewater phosphorus load by 66 percent while a phosphorus detergent ban would reduce the load by about 28 percent. These reductions correspond to approximately 15 percent and 6 percent, respectively, of the estimated bioavailable phosphorus loading to the lake. Because of the greater impact of effluent limitations, the four treatment plants in the basin were investigated for the feasibility of immediately implementing simultaneous chemical precipitation of phosphorus. The investigations indicated that it was feasible at the three largest plants and would require relatively small capital expenditures. Annual per capita costs for phosphorus removal at the three plants were estimated to be $5, $9, and $14/person/year and would result in a phosphorus load reduction of 15 metric tons per year to Flathead Lake. Annual costs to the consumer of a phosphate detergent ban were conservatively estimated to be $11 per household. Thus, the estimated annual costs of the two strategies are $10.23/kg P reduction for phosphorus removal at the treatment plants and $32.37/kg P reduction for a phosphate detergent ban. The study concluded that immediate implementation of chemical treatment at the municipal treatment plants rather than a phosphorus detergent ban should be pursued vigorously as a more effective means of controlling wastewater phosphorus sources. |
| SOURCES, LOCATIONS, AND CONTROL OF URBAN RUNOFF POLLUTANTS IN THE PIEDMONT OF NORTH CAROLINA | John R. Dorney; William A. Kreutzberger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 165 - 169 | SOURCES, LOCATIONS, AND CONTROL OF URBAN RUNOFF POLLUTANTS IN THE PIEDMONT OF NORTH CAROLINA | Controlling nonpoint pollution from developed urban areas has generally been considered impractical. In basinwide studies of toxicants upstream of two new nutrient-sensitive drinking water reservoirs, 516 small urban subdrainage basins in eight North Carolina cities were analyzed in detail. Each subbasin's area and land use were determined and pollutant loading factors lbs/acres/yr) applied. Except for nutrients, urban nonpoint sources contributed more pollutants than urban point sources. Pollutants were not evenly distributed across these cities; one-third of the area contributed about two-thirds of each city's copper, lead, zinc, total phosphorus, and total suspended solids (TSS), and about one-half of the total nitrogen, total Kiedahl nitrogen (TKN), and chemical oxygen demand (COD). If small detention basins were installed to control runoff from this one-third of each city, about one-half of the lead and total suspended solids and one-third of the zinc and total phosphorus would be removed from runoff from the entire city. |
| RECENT PROGRESS ON IMPROVING RESERVOIR RELEASES | Charles E. Bohac; Richard M. Shane; E. Dean Harshbarger; H. Morgan Goranflo | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 187 - 190 | RECENT PROGRESS ON IMPROVING RESERVOIR RELEASES | The progress made in the past two years on improving dissolved oxygen (DO) and flow conditions below Tennessee Valley Authority (TVA) hydropower projects is discussed. New methods of turbine aspiration have resulted in dissolved oxygen increases of up to 3.5 mg/L with efficiency losses of about 0.5 percent. A regulation weir made from gabions has provided a continuous minimum streamflow of 5.7 m3/sec below a hydropower project where previously no flow had existed for extended periods. Comparisons between sluicing, adding a small hydroturbine to the powerhouse, providing a regulating weir, and pulsing existing turbines resulted in the selection of a small hydro addition to provide a continuous minimum flow below a second project. |
| PROJECT COMPLETION SUMMARY OF THE EFFECTS OF RESTORATION PROCEDURES AT LIBERTY LAKE, WASHINGTON | David S. Lamb; Stephen A. Breithaupt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 204 - 209 | PROJECT COMPLETION SUMMARY OF THE EFFECTS OF RESTORATION PROCEDURES AT LIBERTY LAKE, WASHINGTON | The implementation phase of the Liberty Lake restoration project included construction of marsh flushing controls, dredging of 21 ha of the lake bottom, and treatment of the lake waters with aluminum sulfate. This work was started in November 1979 and completed in May 1981. After four years of postrestoration water quality monitoring nutrient levels in the lake and inflowing waters have been reduced, and the trophic state has declined toward a more mesotrophic condition. Comparison of pre- and postrestoration nutrient budgets indicates that a reduction in phosphorus loading of 34 percent was achieved. It appears that the sewering was primarily responsible for this reduction. Although the desired change in the phytoplankton community (from primarily blue-green to primarily green algae) did not occur, indications are that long-term productivity and incidence of blue-green blooms has been significantly reduced. In addition, if the restoration had not been done when it was, water quality in Liberty Lake would have been severely degraded because of high flood flows and nutrient loading through the marsh system. The realized benefits of, and problems with, the individual efforts involved in this multiphased project are documented in the following discussion. |
| THE FALMOUTH NUTRIENT LOADING BYLAW: A REGULATORY APPROACH TOWARD MINIMIZING THE EFFECT OF NUTRIENTS UPON FRESH AND COASTAL WATER SYSTEMS | Jon D. Witten | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 210 - 213 | THE FALMOUTH NUTRIENT LOADING BYLAW: A REGULATORY APPROACH TOWARD MINIMIZING THE EFFECT OF NUTRIENTS UPON FRESH AND COASTAL WATER SYSTEMS | The Falmouth, Mass., Nutrient Loading Project focuses on the presumption that housing density within the watersheds of fresh and coastal ponds is related to water quality. In the fall of 1982, the town began investigating the relationship between water quality and the extent to which septic systems, lawn fertilizers, and road drainage leached into water systems. The town was (and remains) reasonably convinced that water quality, both fresh and salt, is dramatically affected by the amount of nutrients entering the water from septic systems and other man-related sources. On this basis, the town devised a means of regulating the amount of nutrients entering the town's water systems vis-a-vis zoning and subdivision controls. |
| LAKE PROFILES: TAILORING LAKE AND WATERSHED DATA FOR LOCAL WATER QUALITY PROTECTION | John E. Gannon; Arthur J. Gold; Donald C. Pelz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 199 - 203 | LAKE PROFILES: TAILORING LAKE AND WATERSHED DATA FOR LOCAL WATER QUALITY PROTECTION | A series of lake-specific booklets, “Lake Profiles,†was developed in northern Michigan to transfer water quality information from a technical information source (the University of Michigan Biological Station) to a local audience (lake property owners and public officials). Each lake profile was devoted to a single water body, averaged 10 pages, and was amply illustrated with maps, photos, and graphs. Sections were included on the history of settlement, limnological and land use characteristics, and the identification of critical concerns potentially affecting water quality degradation. A followup questionnaire indicated that the lake profiles were, indeed, effective in communicating water quality information and aided in the local initiation of specific lake protection programs. The development of each lake profile involved frequent meetings with local residents and officials and cosponsorship by a lake property owners' association. Although the lake-specific content of the booklets was important, we attribute the success of this program as much, if not more so, to the process of developing the lake profiles with local involvement. |
| BENEFITS ASSOCIATED WITH MEETING WATER QUALITY STANDARDS AT LAKE TANEYCOMO, MISSOURI | A. Stephen Weithman; Mark A. Haas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 191 - 194 | BENEFITS ASSOCIATED WITH MEETING WATER QUALITY STANDARDS AT LAKE TANEYCOMO, MISSOURI | Lake Taneycomo, a 700-ha hydropower impoundment in southwestern Missouri, supports an excellent put-grow-and-take trout fishery with a benefit:cost ratio of 22:1. However, seasonal dissolved oxygen fluctuations resulting from the hypolimnetic discharge from upstream Table Rock Lake have been a concern since 1970. The biological and socioeconomic effects of low levels of dissolved oxygen on the fishery were recently documented. When dissolved oxygen drops below 6 mg/L, fishing success declines. This change in fishing quality affects visitation to the area and the economic benefits generated by the fishery. The net economic benefit of the fishery to the local economy is $9.9 million, and the current estimated loss of benefits is $358,000 per year because of low dissolved oxygen. The U.S. Army Corps of Engineers has proposed a structural modification of Table Rock Dam to solve the problem. |
| LEGAL ASPECTS OF RESERVOIR RELEASES | John W. Attey; Drew R. Liebert | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 2 | 1 | 1986 | 195 - 198 | LEGAL ASPECTS OF RESERVOIR RELEASES | The primary goal of the Clean Water Act is “to restore and maintain the chemical, physical and biological integrity of the nation's waterways.†One measure of that integrity is the dissolved oxygen content of water, which can be dangerously altered by the structure of dams and hydroelectric plants. However, two federal courts of appeals have held that Congress did not intend to regulate the destructive discharges of dams under the Clean Water Act. This paper briefly describes the relationship between dissolved oxygen and water quality and explains how dams and hydroelectric facilities pollute the surrounding waters. The paper concludes that the erroneous decisions of the two circuit courts are serious threats to the economic viability and biological integrity of the nation's waterways. Actions by both Congress and the Environmental Protection Agency are suggested. |
| VERIFICATION OF THE RESERVOIR WATER QUALITY MODEL, CE-QUAL-R1, USING DAILY FLUX RATES | Carol Desormeau Collins; Joseph H. Wlosinski | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 206 - 211 | VERIFICATION OF THE RESERVOIR WATER QUALITY MODEL, CE-QUAL-R1, USING DAILY FLUX RATES | Emphasis on evaluation techniques where measured versus predicted changes of mass are compared can produce a model that predicts the correct answers for the wrong reasons. The movement of mass between compartments (flux) should be compared to measured flux as part of the model verification. Model verification techniques need to reflect the same level of resolution inherent in the model structure. The U.S. Corps of Engineers water quality model, CE-QUAL-R1, was verified for DeGray Lake, Ark., using this procedure. Several processes important in determining the mass of the constituents were measured for DeGray Lake. Primary production rate and settling rates of algae, total dry weight, and organic matter were compared to predicted fluxes. Results indicated that the model was satisfactory in predicting trends in flux values. |
| RELATIONSHIPS BETWEEN SUSPENDED SOLIDS, TURBIDITY, LIGHT ATTENUATION, AND ALGAL PRODUCTIVITY | Russ Brown | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 198 - 205 | RELATIONSHIPS BETWEEN SUSPENDED SOLIDS, TURBIDITY, LIGHT ATTENUATION, AND ALGAL PRODUCTIVITY | The effects on algal productivity of changes in light availability because of suspended materials entering a lake from storm runoff or turbidity generated by wind mixing of sediments are often discussed. The relationships between suspended solids, turbidity, Secchi disk depth, light attenuation, and the resulting photosynthetic response of algae are not well documented. Data from several TVA reservoirs indicate that variations in the available light due to turbidity of the water are large and must be described in more detail before accurate predictions of algal dynamics and macrophyte growth can be achieved. Basic relationships between the various measurements of turbidity, suspended solids, Secchi disk depth, and light attenuation are given. This allows frequent measurements of turbidity or Secchi disk depth to be combined with daily solar radiation and less frequent chlorophyll and C14productivity data to yield a detailed estimate of algal productivity within a reservoir or lake throughout the year. For long lakes and many reservoirs, significant longitudinal gradients in suspended solids will result as the inflowing materials settle and the water column clears. The importance of this gradient of available light for modeling algal dynamics is demonstrated with data from several TVA reservoirs. |
| PHYTOPLANKTON-NUTRIENT RELATIONSHIPS IN SOUTH CAROLINA RESERVOIRS: IMPLICATIONS FOR MANAGEMENT STRATEGIES | Jeffrey Pearse | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 193 - 197 | PHYTOPLANKTON-NUTRIENT RELATIONSHIPS IN SOUTH CAROLINA RESERVOIRS: IMPLICATIONS FOR MANAGEMENT STRATEGIES | Using existing data selected from a large government data base, an analysis of the factors governing algal standing crop in 40 South Carolina reservoirs revealed that chlorophyll a production was considerably lower than that reported for northern temperate lakes. This observation was attributed to the high levels of nonalgal turbidity frequently exhibited by the study reservoirs. The accuracy of eight literature models in predicting chlorophyll was examined and most were found to overestimate actual ambient values. To account for the various moderating factors affecting chlorophyll production in turbid reservoirs, the use of multivariate models is suggested. The results of this study indicate that local conditions should be taken into account when selecting a predictive model for management purposes. One feasible option for government agencies is to develop predictive models using readily available data. |
| A HISTORICAL PERSPECTIVE AND PRESENT WATER QUALITY CONDITIONS IN BEAR LAKE, UTAH-IDAHO | Vincent A. Lamarra; V. Dean Adams; Craig Thomas; Rex Herron; Paul Birdsey; Victor Kollock; Mary Pitts | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 213 - 218 | A HISTORICAL PERSPECTIVE AND PRESENT WATER QUALITY CONDITIONS IN BEAR LAKE, UTAH-IDAHO | In the 1975 National Eutrophication Survey Bear Lake had the best overall water quality of all Utah lakes sampled. However, this oligotrophic state would not be retained because of a mesotrophic level of loading. Because of the unique characteristics of the Bear Lake ecosystem and the present danger of cultural eutrophication, the objectives of this 314 Clean Lakes Study were to: (1) quantify the major nonpoint sources of nitrogen and phosphorus into Bear Lake; (2) quantify the major sources of nitrogen and phosphorus in the Bear River prior to its diversion into Dingle Marsh and Bear Lake; (3) determine the nitrogen, phosphorus, and carbon budgets of Dingle Marsh and define the factors which may regulate the flux of these nutrients into Bear Lake; and (4) if necessary, develop a set of viable cost-effective alternatives for the reduction of the nitrogen and phosphorus loading into Bear Lake. Nutrient loading was determined for each major tributary to Bear Lake and the trophic condition of the lake was determined over an 18-month period. Trophic state determinations were made using TSI values, areal oxygen deficits, and areal phosphorus loadings. Differences in parameters predictions are explained. An historical perspective of the water quality trends is given for Bear Lake (1975-1983). Based upon the observed changes and associated land use alterations, a series of management plans is proposed for maintaining or improving the water quality in Bear Lake. |
| THE EFFECT OF COPRECIPITATION OF CaCO3AND PHOSPHORUS ON THE TROPHIC STATE OF BEAR LAKE | Paul Birdsey; Vincent Lamarra; V. Dean Adams | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 229 - 233 | THE EFFECT OF COPRECIPITATION OF CaCO3AND PHOSPHORUS ON THE TROPHIC STATE OF BEAR LAKE | Bear Lake is a hardwater lake located in a limestone basin on the border of Utah and Idaho with a surface area of 282 km2, maximum depth of 63 m, and a mean depth of 10 m. The lake was formed by tectonic activity approximately 28,000 years B.P. with no natural outfall. Inflow mainly from small tributaries probably did not equal evaporation. These conditions resulted in a concentration of carbonate salts and a unique macrochemistry, with magnesium as the predominant divalent cation. The isolation from any major drainages also led to the development of endemic fish species. In 1912, Utah Power and Light Company completed a series of canals diverting water from the Bear River into the lake during the spring and later released for downstream irrigation and power needs. Diversion of the Bear River into the lake increased water flow and presumably loadings by as much as 70 percent above historic conditions. A 2-year study recently completed found nutrient loadings into Bear Lake at meso-eutrophic levels, but the lake limnologically oligo-mesotrophic. Phosphorus was the principal limiting nutrient. Because of this apparent anomaly in trophic status and the known relationship between calcium carbonate and phosphorus in marl lakes, this study was undertaken to quantify the reduction of potential algal biomass through coprecipitation of phosphorus. Initially, three different phosphorus levels were added to synthetic Bear Lake medium without algae to determine if coprecipitation would occur under ideal conditions. The pH of the medium was raised artificially with NaOH to 8.5, a value not uncommon in Bear Lake. After 4 days 100 percent of the phosphorus had precipitated in the 10 μg P/l treatment. Bioassays were then conducted in softwater and Bear Lake media with Selenastrum capricornutum at 10 different phosphorus levels. At similar nutrient levels the maximum biomass reached twice that of the biomass in the Bear Lake medium. These may explain the low primary production experienced in many hardwater lakes and Bear Lake in particular. It may also be inferred that a potential self-cleansing mechanism exists within Bear Lake that would allow a rapid reversion to historic water quality if nutrient loadings were reduced. |
| THE NITROGEN, PHOSPHORUS, AND CARBON BUDGETS OF A LARGE RIVERINE MARSH, AND THEIR IMPACT ON THE BEAR LAKE ECOSYSTEM | Rex C. Herron; Vincent A. Lamarra; V. Dean Adams | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 223 - 228 | THE NITROGEN, PHOSPHORUS, AND CARBON BUDGETS OF A LARGE RIVERINE MARSH, AND THEIR IMPACT ON THE BEAR LAKE ECOSYSTEM | Adjacent to the north end of Bear Lake is a large (65 km2) freshwater marsh. Prior to 1912, Dingle Marsh was separated from Bear Lake by a naturally occurring sandbar and covered approximately 100 km2. Seventy years ago, Utah Power and Light constructed a canal system which effectively diverted the Bear River into Dingle Marsh. The present water system operates by diverting spring water from the Bear River through the marsh and into Bear Lake. During late summer when irrigation demand is high, water is removed from the lake, passed through the marsh, and released into the river. The major objective of this portion of the Clean Lakes Study was to determine the nitrogen, phosphorus, and carbon budgets of Dingle Marsh and define the factors that may regulate the flux of these nutrients into Bear Lake. Sixteen sites within the marsh and all major inflows and outflows were sampled over an 18-month period. The data indicated specific seasonal trends within the marsh (sources or sinks) of the target nutrients. Furthermore, the marsh mass balances indicated that on an annual basis, the marsh acted as a sink. However, during specific periods of time, nitrogen, phosphorus, and carbon were produced within the marsh system and exported (the marsh was a source). Management alternatives were generated as a result of this portion of the project to maximize the marsh as a nutrient sink for inflowing Bear River water. |
| SOCIOECONOMIC AND POLITICAL ISSUES ASSOCIATED WITH THE IMPLEMENTATION PHASE OF THE BEAR LAKE 314 CLEAN LAKES STUDY | Craig Thomas; Vincent Lamarra; V. Dean Adams | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 219 - 222 | SOCIOECONOMIC AND POLITICAL ISSUES ASSOCIATED WITH THE IMPLEMENTATION PHASE OF THE BEAR LAKE 314 CLEAN LAKES STUDY | As a result of the diagnostic portion of the 314 Clean Lakes Study on Bear lake, three alternatives were selected because of their expected water quality improvement potential, technical feasibility, environmental impact, and estimated cost: (1) site specific recommendations—Upper Bear River watershed management, Dingle Marsh modifications, and the use of BMP's in two small problem watersheds within the Bear Lake drainage; (2) a site specific basinwide water quality management plan; and (3) an environment information and education program. Because of the limitation in Phase II Clean Lakes moneys, the implementation of the diagnostic study was difficult. A case history is presented on how the project was continued. Because of the location of Bear Lake, four Federal agencies and three States became involved in the existing Bear Lake Preservation Project. An example of the value of a Regional Commission and the important coordinating role played by this type of agency will be discussed. |
| USE OF A PREDICTIVE PHOSPHORUS MODEL TO EVALUATE HYPOLIMNETIC DISCHARGE SCENARIOS FOR LAKE WALLENPAUPACK | H. Kirk Horstman; Roger S. Copp; Frank X. Browne | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 165 - 170 | USE OF A PREDICTIVE PHOSPHORUS MODEL TO EVALUATE HYPOLIMNETIC DISCHARGE SCENARIOS FOR LAKE WALLENPAUPACK | A vertically-segmented, dynamic phosphorus model program was developed for use on a 16 bit microcomputer. The predictive model includes theoretical equations for physical settling, thermocline diffusion, and sediment release of total phosphorus. The model was developed and calibrated using actual data collected from 1980 through 1982. Input loads from combined point and nonpoint sources were entered using a time step equal to 1 day. In the case of Lake Wallen-paupack, discharge occurs from both the epilimnion and hypolimnion during the latter portion of the stratified period. Several discharge scenarios were evaluated to determine if any one would produce a significant reduction in summer epilimnetic phosphorus concentrations. |
| SPRING DAPHNIA RESPONSE IN AN URBAN LAKE | Terry A. Noonan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 157 - 163 | SPRING DAPHNIA RESPONSE IN AN URBAN LAKE | Water quality has been monitored in Lake Phalen (St. Paul, Minn.) from 1981 to 1983. Consistent increases in epilimnetic Daphnia abundance have been observed each spring, corresponding to measured Secchi depth maxima. In 1982 and 1983 the increase in Daphnia abundance followed an increase in the density of small algae, principally Cryptomonas sp. The increase in Daphnia density in 1981, when small algal forms were not abundant, suggests another factor, such as predation, may control spring Daphnia abundance in Phalen. The impact of the spring increase in Daphnia abundance on summer water quality appears slight. A significant difference in summer mean chlorophyll a concentration between years is not related to a change in epilimnetic Daphnia abundance. Summer algal standing crop in Lake Phalen is related to both nutrient and biological factors, including partial nitrogen limitation and changes in phytoplankton community composition. |
| BIOLOGICAL CONTROL OF NUISANCE ALGAE BY DAPHNIA PULEX: EXPERIMENTAL STUDIES | Michael J. Vanni | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 151 - 156 | BIOLOGICAL CONTROL OF NUISANCE ALGAE BY DAPHNIA PULEX: EXPERIMENTAL STUDIES | The feasibility of using the zooplankton species Daphnia pulex as a biological control agent of nuisance algal blooms was investigated experimentally in two Illinois lakes. Two questions were posed: (1) Can grazing by Daphnia pulex buffer the effects of increased nutrient loading to an initially low-nutrient lake? and (2) Can D. pulex significantly reduce algal biomass when introduced into a lake that already exhibits excessive phytoplankton growth? These questions were answered by introducing D. pulex individuals into large enclosures (1,000 liters) suspended in the lakes, which do not naturally contain D. pulex . The first question was addressed in Dynamite Lake, an oligo-mesotrophic quarry lake that does not normally exhibit algal blooms. Four treatments were employed within the enclosures: (1) a control, (2) D. pulex added, (3) nutrients (nitrogen and phosphorus) added, and (4) D. pulex and nutrients added. Nutrients were not added until the D. pulex populations became established and were added at weekly intervals after initial addition. In an experiment performed in 1982 D. pulex displayed the ability to substantially buffer the effects of increased nutrient loading. Although addition of nutrients increased phytoplankton biomass in all enclosures to which they were added, by the end of the experiment enclosures without D. pulex had phytoplankton densities (measured as chlorophyll a concentration) greater than those with D. pulex . The second question was addressed in Larimore Pond, a highly eutrophic farm pond with a dense summer surface bloom of phytoplankton. One experiment in the summer of 1982 was performed with a control and with D. pulex added. The results were quite striking: by the end of the experiment (roughly 6 weeks) enclosures without D. pulex exhibited phytoplankton densities an order of magnitude greater than those with D. pulex . These results demonstrate that D. pulex can effectively control phytoplankton biomass even in lakes in which D. pulex is not a natural inhabitant. Therefore, management strategies designed to facilitate introduction and survival of D. pulex or other large grazers should be encouraged as a viable within-lake technique for mitigating the symptoms of eutrophication. |
| WATER QUALITY SIMULATION OF THE PROPOSED JORDANELLE RESERVOIR, UTAH | David L. Wegner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 171 - 174 | WATER QUALITY SIMULATION OF THE PROPOSED JORDANELLE RESERVOIR, UTAH | Jordanelle Reservoir, a proposed component of the Bonneville Unit of the Central Utah Project, will be a major source of municipal and industrial water for the Salt Lake Valley. The final environmental impact statement identified the need to evaluate Jordanelle in terms of its downstream impact on Deer Creek Reservoir and the use of the water. To evaluate the impact, a combination of temperature and water quality simulation models, anaerobic simulation of the sediments, empirical nutrient loading models, and estimates of primary productivity were utilized. As a result of these efforts, Jordanelle Reservoir is expected to experience seasonal excesses of eutrophication with resulting low dissolved oxygen levels, potential mobilization of mine tailings, and seasonal recycling of nutrients from the sediments. To restrict the impact of these factors on downstream productivity and to allow efficient routing of nutrients and water through Deer Creek Reservoir, a multiple level withdrawal outlet structure and variable operation scenarios were designed for Jordanelle. The simulation period covered the entire stagnation period with the coefficients defined from previous Deer Creek simulations, the proposed Jordanelle operation plan, and empirical relationships. The procedures defined will be integrated with a watershed management plan to provide for efficient use of Jordanelle water with the resulting least impact to the downstream use of water. This analysis has applications to other impoundments and the determination of efficient operation plans. |
| A CROSS-SECTIONAL MODEL FOR PHOSPHORUS IN SOUTHEASTERN U.S. LAKES | Kenneth H. Reckhow; J. Trevor Clements | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 186 - 192 | A CROSS-SECTIONAL MODEL FOR PHOSPHORUS IN SOUTHEASTERN U.S. LAKES | Data from 42 lakes and reservoirs in Virginia, North Carolina, South Carolina, and Georgia were used to develop and evaluate cross-sectional regression models for phosphorus. For all models under consideration, the endogenous variable was lakewide average annual phosphorus concentration, and the exogenous variables were phosphorus input to the lake and various geomorphologic and hydrologic variables. A linear model was developed for logarithmically-transformed terms that resulted in a substantially lower prediction sum of squares than did other models under consideration. Among the other models examined were those specified and fitted to north temperate lakes by other investigators. Parameter characteristics and error terms for the proposed model were studied with particular attention directed to the a priori assumption of a strictly linear relation between input and concentration of phosphorus. The calculation of prediction uncertainty is illustrated in an application of the model using an empirical Bayes approach and a prior model based on linearity. |
| MODELING DEVELOPMENTS ASSOCIATED WITH THE UNIVERSITY LAKES RESTORATION PROJECT | Ronald F. Malone; Daniel G. Burden; Constantine E. Mericas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 182 - 185 | MODELING DEVELOPMENTS ASSOCIATED WITH THE UNIVERSITY LAKES RESTORATION PROJECT | Water quality models have been applied to the six University Lakes of Baton Rouge, La., to assist in the analysis of effects of restoration efforts. Phosphorus was identified as the nutrient limiting algal growth in these lakes. A relationship between total phosphorus and fishkills was identified. Initial applications of a modified Vollenweider model indicated that the model was capable of projecting long-term average lake conditions but that it was limited by its inability to represent short-term variations. These variations were crucial for the projection of fishkill episodes. Intensive surveys failed to identify practical modifications to the model within a deterministic format and a stochastic approach was undertaken. Uncertainties were partitioned into terms representing lumped modeling errors and sampling variability. This approach produced results that were suitable for interfacing with objective functions based upon total phosphorus levels. The need for more widespread application of stochastic techniques was evident from experiences associated with this project. |
| TIME SERIES MODELING OF RESERVOIR WATER QUALITY | Robert H. Montgomery | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 175 - 181 | TIME SERIES MODELING OF RESERVOIR WATER QUALITY | Time series models of reservoir water quality are water resource management tools and provide insight into reservoir dynamics since they account for autocorrelation, seasonality, and trends present in the data. Autoregressive integrated moving average (ARIMA) models were applied to describe patterns in selected water quality variables of Red Rock Lake, Iowa. Models were generated for total phosphorus, total nitrogen, and suspended solids for an 8-year period (1972-1979). Patterns in lake concentration and the usefulness of time series models to lake and reservoir management are described. |
| ORGANIC MATTER SUPPLY AND PROCESSING IN LAKES AND RESERVOIRS | Alan W. Groeger; Bruce L. Kimmel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 282 - 285 | ORGANIC MATTER SUPPLY AND PROCESSING IN LAKES AND RESERVOIRS | The estimation of annual organic matter budgets for lakes and reservoirs can be an important initial step in investigating aquatic ecosystem structure and function. Comparison of organic matter budgets for a number of aquatic systems indicates that hydraulic retention time exerts a critical influence on the efficiency with which those systems process and trap their organic matter inputs. Generally, lakes or reservoirs with short retention times have high drainage basin area: water surface area ratios, and receive large quantities of allochthonous organic matter. These rapidly flushed ecosystems are relatively inefficient in retaining and processing their inputs and transport large quantities of organic matter downstream. Lakes or reservoirs with long retention times have low drainage basin area: water surface area ratios and are dominated by autochthonous inputs. These ecosystems are considerably more efficient in retaining and processing their inputs, and lose little organic matter downstream. Lakes and reservoirs with similar retention times and drainage basin area: water surface area ratios tend to behave similarly, both in the relative importance of allochthonous inputs and in the efficiency with which organic matter inputs are processed and trapped within the ecosystem. |
| FACTORS CONTROLLING PRIMARY PRODUCTION IN LAKES AND RESERVOIRS: A PERSPECTIVE | Bruce L. Kimmel; Alan W. Groeger | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 277 - 281 | FACTORS CONTROLLING PRIMARY PRODUCTION IN LAKES AND RESERVOIRS: A PERSPECTIVE | Phytoplankton productivity and biomass fluctuations are controlled by the same energy and nutrient inputs and the same balance of gain and loss factors in natural and manmade lakes. However, some significant physical and hydrodynamic differences between lakes and reservoirs do exist which influence (1) the relative contributions of various primary producers to their food-webs, (2) the relative importance of certain limiting factors to primary production (e.g., turbidity, nutrient availability, flushing rate), (3) the spatial variability of primary production within reservoirs, and (4) the applicability of lake-based classifications and empirical relationships to reservoirs. An important distinction between most natural and manmade lakes is that reservoirs are semi-fluvial environments that fall between rivers and lakes on a continuum of aquatic ecosystems. A wider recognition of the riverine influences on reservoir ecosystems will enhance our understanding of the spatial and temporal heterogeneity associated with manmade impoundments and, thereby, permit more effective management of reservoir resources. |
| INTERMOUNTAIN WEST RESERVOIR LIMNOLOGY AND MANAGEMENT OPTIONS | Jerry Miller | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 272 - 276 | INTERMOUNTAIN WEST RESERVOIR LIMNOLOGY AND MANAGEMENT OPTIONS | |
| MIXING EVENTS IN EAU GALLE LAKE | Robert F. Gaugush | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 286 - 291 | MIXING EVENTS IN EAU GALLE LAKE | Eau Galle Lake (Spring Valley, Wis.), a U.S. Army Engineers reservoir, is more susceptible to weather-related mixing events than most north temperate lakes. Bottom withdrawal at Eau Galle leads to considerable heat storage in the hypolimnion and by late summer there is only 6-8° C difference between surface and bottom temperatures. Steep metalimnetic gradients never develop and as a result the reservoir has a relatively low thermal stability, which implies a susceptibility to weather-induced (i.e., wind or cold front passage) mixing events. Two types of mixing events were observed in Eau Galle Lake in the summers of 1981 and 1982: (1) Small scale mixes similar to those observed in lakes. These events lead to net movement of nutrients into the epilimnion and a resultant increase in chlorophyll a concentrations. (2) Large scale mixes that function essentially as short-lived turnovers. These large scale mixes are preceded by a cooling trend in air temperature which results in heat loss from the surface of the reservoir. Surface cooling reduces the already small temperature differences between surface and bottom and sufficient wind can produce considerable mixing. These events lead to the introduction of oxygen into the previously anoxic hypolimnion and rather than increasing epilimnetic concentrations of nutrients, there is a general loss throughout the water column. Low thermal stability and susceptibility to mixing may be a common feature of bottom withdrawal reservoirs and may exert a considerable influence on nutrient and phytoplankton dynamics. |
| RECENT APPLICATIONS OF HYDROACOUSTICS TO ASSESSMENT OF LIMNETIC FISH ABUNDANCE AND BEHAVIOR | Richard E. Thorne; Gary L. Thomas | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 305 - 309 | RECENT APPLICATIONS OF HYDROACOUSTICS TO ASSESSMENT OF LIMNETIC FISH ABUNDANCE AND BEHAVIOR | Since 1969, the authors have been involved in over 200 hydroacoustic surveys of fish populations in more than 25 lakes. These studies have included a variety of different species assemblages and objectives, although most, such as Lakes Washington and Ozette in Washington and Tustumena in Alaska, are sockeye salmon nursery lakes. The objectives of these studies have included fisheries management, evaluation of lake enhancement programs, or environmental impact. During the 14 years of these investigations, both the equipment and procedures have evolved and improved considerably. Earlier techniques were very limited in their ability to detect fish near surface or in shallow water and had very limited capabilty for size discrimination. Current technology has solved most of these problems. These developments and their capabilities are presented along with the results of surveys on lakes with a variety of biological and physical characteristics. The results include a considerable amount of “ground truth†data from other assessment techniques. In many cases these data are obtained from various net sampling techniques. However, some comparisons have revealed considerable biases with net sampling techniques which are associated with changes in light intensity, turbidity, or fish behavior. |
| EFFECTS OF FISH ATTRACTORS ON SPORT FISHING SUCCESS ON NORRIS RESERVOIR, TENNESSEE | R. Glenn Thomas; J. Larry Wilson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 299 - 304 | EFFECTS OF FISH ATTRACTORS ON SPORT FISHING SUCCESS ON NORRIS RESERVOIR, TENNESSEE | A creel survey was conducted in 1980 on Norris Reservoir, Tenn., from March through October to assess the effects of artificial fish attractors (also known as hides, havens, shelters, or reefs) on fisherman success. An average of 9.8 brush-pile attractors was installed in each of 259 coves in the lake by TVA/CETA between 1978 and 1980. The 7.5-month creel survey yielded 1,435 party interviews, separating those fishermen who had fished only attractor areas (115 individuals) from those who had fished other areas exclusively (2,582), and those who had fished both attractor and nonattractor sites. Ten species of fish were caught by attractor fishermen, whereas nonattractor fishermen caught specimens of 19 species, and those who had fished both area types on the same day accounted for 15 species. Comparisons of attractor and nonattractor creels indicated that percent successful, mean number of fish caught, mean fish per man/hour, and mean kilograms per man/hour were all significantly higher for attractor fisherman. Analysis of variance showed that those fishermen angling primarily for crappie (Pomoxis spp.) caught significantly more fish per man/hour and kilograms per man/hour, contributing most to the higher overall success rates for attractor fishermen. |
| EMPIRICAL PREDICTION OF CHLOROPHYLL IN RESERVOIRS | William W. Walker Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 292 - 297 | EMPIRICAL PREDICTION OF CHLOROPHYLL IN RESERVOIRS | The use of nutrient loading models for predicting the trophic status of lakes and reservoirs is based partially upon empirical phosphorus/chlorophyll relationships which were originally developed using data from northern natural lakes. Recently, increased attention has been given to the effects of other potentially limiting factors, including nitrogen, light, and flushing rate, on the performance of empirical chlorophyll models. This paper describes a study of these relationships in reservoirs and is derived from a nationwide research project conducted for the U.S. Army Corps of Engineers. Effects of N/P ratios, flushing rate, turbidity, and impoundment morphometry on phosphorus/chlorophyll relationships are systematically evaluated. Apparent lake/reservoir differences in average chlorophyll response to phosphorus are related more to the limited generality of phosphorus/chlorophyll regression models and to regional factors than to effects of impoundment type. The analysis has led to the development of a more general model which explicitly accounts for effects of algal growth limitation by phosphorus, nitrogen, light, and flushing rate. |
| SEDIMENT DISTRIBUTION AND QUALITY IN A SMALL WISCONSIN RESERVOIR | Robert C. Gunkel Jr.; Robert F. Gaugush; Robert H. Kennedy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 243 - 247 | SEDIMENT DISTRIBUTION AND QUALITY IN A SMALL WISCONSIN RESERVOIR | Eau Galle Lake is a small Corps of Engineers impoundment on the Eau Galle River in west central Wisconsin. A sediment survey was conducted to document reservoir sediment characteristics in relation to reservoir morphometry, hydrodynamics, and water quality. Sediment conditions at Eau Galle Lake tend to be lakelike, rather than exhibiting a more typically reservoir-like dependence on hydrodynamics. Sediment distribution patterns in the reservoir are primarily influenced by basin morphometry, which has resulted in sediment deposition and quality being depth related. A deep central basin, circular shape, and multiple inflows have contributed to the existence of two distinct sedimentary zones. The transport zone, which is characterized as a high-energy environment, exists in the shallow, littoral areas of the reservoir. Turbulent processes dominate the transport zone, thereby, discouraging the permanent deposition of fine particulates. As a result, transport zone sediments have a relatively large median particle size and low moisture content. The deep central basin of the reservoir is characterized as an accumulation zone of low energy. Sediments in this less turbulent area are characterized by a smaller median particle size and high moisture content. Sediment chemical characteristics of nutrients, metals, and organic matter are higher in the accumulation zone. Therefore, the deep sediments may be more influential to water quality through exchanges at the sediment/water interface. |
| SEDIMENT INFLOWS AND WATER QUALITY IN AN URBANIZING WATERSHED | David F. Brakke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 239 - 242 | SEDIMENT INFLOWS AND WATER QUALITY IN AN URBANIZING WATERSHED | Lake Whatcom is a large, deep, monomictic lake in the Puget lowlands of Washington State. Expanding development from the city of Bellingham and a large diversion of water from the Nooksack River to the lake are two recent impacts. Bellingham depends on the lake as its sole drinking and industrial water supply. Additionally, the lake is an important recreational resource. Monitoring of the lake began in 1962 and was continuous to 1972, and recent work began in 1979. These data and information from sediment cores have been used to determine trends in water quality. Historically, watershed uses were mainly logging and some coal mining. Sedimentation rates based on Pb-210 were about 0.5 cm/yr. More recently, sedimentation rates have increased to 0.8-1.2 cm/yr., apparently due to increased runoff related to urbanization and the diversion of Nooksack River water containing glacial meltwater with high particulate loads. Much of the particulate material is sedimented in a 6.5 ha lake below the diversion tunnel (volume has decreased 20 percent since 1962), but very fine particulates are transported through this lake to Lake Whatcom. These silt and clay-sized particles may sorb phosphorus descending through the water column. Nutrient concentrations and sediment metal concentrations increase toward the urbanized portions of the watershed. The city water intake is located in the shallowest, most nutrient-rich basin, containing the greatest development densities. Water level regulation is also an issue due to conflicting uses of shoreline development, water storage and use and downstream encroachment. Due to the flashiness of watershed streams, water and sediment transport can cause problems for lake level manipulation and water quality. A Phase 1 lake restoration study funded by the State of Washington is underway, and results will be discussed. |
| SEDIMENT METALS ACCUMULATION IN A SUBURBAN LAKE | John D. Koppen; Stephen J. Souza | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 235 - 238 | SEDIMENT METALS ACCUMULATION IN A SUBURBAN LAKE | Lake Hopatcong is a 1,087 ha lake located in the suburban New York metropolitan area in Sussex and Morris Counties, N.J., and is the head waters of the Musconetcong River in the Delaware River Drainage Basin. The lake watershed is 5,483 ha in area with 71 percent forested and 25 percent in high-density residential development that is clustered around the immediate shoreline of the lake. The recreational use of the lake is extremely heavy, with an excessive number of large motor boats. Also, stormwater from the residential areas empties directly into the lake via storm sewers and direct runoff. Preliminary analysis of selected sediment samples indicated substantial levels of metals (especially lead) in the surficial sediments. As part of a Sec. 314 Lake Restoration study a series of 30 shallow sediment core samples were taken at various locations throughout the lake. These were analyzed for lead, aluminum, iron, zinc, mercury, cadmium and percent of solids. The results indicated significant concentrations of lead and zinc in the most recent sediments as compared to the background levels in the older and deeper sediments. Also, the spatial distribution of sediment metals within the lake was investigated to attempt to identify their sources. The implications of these findings and management implications based on the information are discussed. |
| ANALYSIS OF SURFICIAL SEDIMENT FROM 63 ILLINOIS LAKES | M. Kelly; R. Hite; K. Rogers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 248 - 253 | ANALYSIS OF SURFICIAL SEDIMENT FROM 63 ILLINOIS LAKES | Surficial sediment samples were collected from 63 Illinois lakes during summer 1979. Samples were analyzed for organic matter, nutrients, heavy metals and organochlorine compounds. For purposes of statistical analysis, lakes were placed into one of several groups (glacial, artificial or miscellaneous). Most lakes were artificial reservoirs and these were subdivided based on geographic location. Spatial variations of glacial lake means were contrasted with artificial lake studies. In an attempt to correlate fish flesh pesticide concentrations with sediment concentrations, no simple linear relationships were discerned. In general, the low organic content of Illinois sediments was probably attributable to the high non-volatile suspended solids loading characteristic of most Illinois lakes. Regardless of organic carbon content, the ratio of C:N remained fairly constant at 14:1. The N:P ratio for Illinois lake sediment of 6:1 was somewhat less than the generally conceded 7:1 for plant material. Most Illinois lakes exhibited fairly low sediment metal/metalloid concentrations. Most chlorinated hydrocarbon pesticides were undetected or occurred at low levels in sediment samples. PCB's were detected only in sediments from seven of the lakes sampled. A classification of Illinois lake sediments based on mean constituent concentrations and respective standard deviations was developed to facilitate interpretation of sediment data. The resultant four tier classification system categorized lake sediments as below normal, normal, elevated, and highly elevated. |
| LAKE-RIVER INTERACTIONS: IMPLICATIONS FOR NUTRIENT DYNAMICS IN RESERVOIRS | Robert H. Kennedy | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 266 - 271 | LAKE-RIVER INTERACTIONS: IMPLICATIONS FOR NUTRIENT DYNAMICS IN RESERVOIRS | Unlike small drainage lakes which receive nutrient inputs from relatively diffuse sources, reservoirs and other river-fed lakes receive a majority of their nutrient income from a single large source located distant from the lake's outlet. Interactions between lake and river, which are governed by hydrology, the thermal structure of the lake, and lake morphology, will, therefore, play an important role in determining the impact and ultimate fate of influent nutrients. These interactions may also affect the manner in which nutrients are recycled and/or distributed within the reservoir or river-fed lake and lead to the establishment of longitudinal gradients in concentration. Studies conducted at DeGray Lake, Ark., and West Point Lake, Ga., both large Corps of Engineers hydropower reservoirs, provide instructive examples of some of the effects of these interactions. Both lakes exhibit longitudinal gradients in nutrient and chlorophyll concentrations which are influenced by the hydrologic characteristics of the major tributary. Exchanges of water and material between hypolimnion and epilimnion are also affected by flow regime. These exchanges play an important role in the seasonal dynamics of nutrients and metals. |
| REGIONAL COMPARISONS OF LAKES AND RESERVOIRS: GEOLOGY, CLIMATOLOGY, AND MORPHOLOGY | Kent W. Thornton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 261 - 265 | REGIONAL COMPARISONS OF LAKES AND RESERVOIRS: GEOLOGY, CLIMATOLOGY, AND MORPHOLOGY | Lakes and reservoirs typically have been considered synonomous; in fact, Hutchinson classifies reservoirs as lake type 73. Processes such as internal mixing, redox reactions, nutrient cycling, and primary production obviously occur in both lakes and reservoirs. The forcing functions or driving variables for lakes and reservoirs, however, may not be identical so the response of these two systems may be different. Regional considerations of the climatic, geologic and geographic differences between lakes and reservoirs indicate why our understanding and available predictive techniques for lakes should be tempered for the proper management or reservoirs. Lakes and reservoirs generally are distributed in different parts of the U.S. Most lakes occur in the glaciated portion of the U.S. while most reservoirs are located in the southeastern, central, southwestern, and western U.S. Geologic differences in these areas have implications for differences in the loading of dissolved and particulate constituents to lakes and reservoirs. Climatic differences such as precipitation-evaporation interactions also result in distinct areas. In the eastern U.S., precipitation exceeds evaporaton, water is plentiful and lakes are prevalent. In the western U.S., evaporation exceeds precipitation, water is scarce and reservoirs are prevalent. Geographic differences influence the management of lakes and reservoirs. Operation of reservoirs for hydropower, irrigation, industrial and public water supply can influence the response of the system to external and internal inputs. The distribution of lakes and reservoirs in conjunction with geologic, climatologic, and geographic patterns would imply potential differences in the limnological response of lakes and reservoirs. Proper management of our water resources requires that we consider these potential differences in the decision process. |
| THE ENGINEERING CHARACTERISTICS OF HYDRAULICALLY DREDGED LAKE MATERIALS | James E. Walsh; Stanley M. Bemben; Carlos Carranza | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 254 - 259 | THE ENGINEERING CHARACTERISTICS OF HYDRAULICALLY DREDGED LAKE MATERIALS | A perception of the engineering characteristics of dredged lake materials is necessary for making decisions regarding the size and type of hydraulic dredge best suited for the proposed project, dredge production rates, containment area size requirements, various containment area operating procedures, the nature of potential containment area reuse, the time necessary for the filled containment area to become available for reuse, and potential measures that may be used to increase the rate of improvement and ultimate strength characteristics of the dredged material in the containment area. The pertinent engineering characteristics are reasonably inferred from bulking, grain size distribution, specific gravity and organic content, Atterberg Limits, consolidation and shear strength data. Typical ranges for these data, including before and after dredging cases, as determined for several sites in the northeastern United States are presented. Significant differences in measured characteristics often occur among samples taken from the lake bottom, from the dredge effluent pipeline or from the containment area. The most important changes in dredged material composition resulting from the dredging and dredged material disposal process are the loss of fines and low specific gravity material. This change should be accounted for when planned dredging projects employ engineering data obtained from samples of lake material to be dredged. |
| LONG TERM GRAZING CONTROL OF ALGAL ABUNDANCE: A CASE HISTORY | Richard A. Osgood | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 144 - 150 | LONG TERM GRAZING CONTROL OF ALGAL ABUNDANCE: A CASE HISTORY | Square Lake, Minn., mimics an ideal of the biomanipulation approach. The lake's zooplankton community is dominated by large (body size) herbivorous cladocerans (Daphnia pulicaria) whose collective grazing abilities have maintained a reduced standing crop of algae, apparently since 1926. The physical and chemical environmental factors that define Daphnia's niche in Square Lake are discussed and include stable stratification, a large hypolimnetic volume, and phosphorus concentrations within certain threshold limits. These environmental limitations seem to be generally important for providing a metalimnetic refuge for Dephnia . Future biotic reconstructions that aim to encourage large-bodied Daphnia should consider these environmental limitations. |
| SURFACE RUNOFF WATER QUALITY FROM DEVELOPED AREAS SURROUNDING A RECREATIONAL LAKE | Jay A. Bloomfield; James W. Sutherland; James Swart; Clifford Siegfried | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 40 - 47 | SURFACE RUNOFF WATER QUALITY FROM DEVELOPED AREAS SURROUNDING A RECREATIONAL LAKE | During 1980, as part of its Nationwide Urban Runoff Program (NURP), the U.S. Environmental Protection Agency entered into a cooperative agreement (P002229-01-1) with the New York State Department of Environmental Conservation to study urban runoff at Lake George, N.Y., located in the southeastern Adirondack Mountains. The purpose of the study was to determine the effect of runoff from a developed watershed on the water quality of the lake and its tributaries. More than 40 storm events were sampled during a 2-year period at six tributary sampling stations to assess the loading of plant nutrients and other contaminants from developed and underdeveloped areas to the open waters of the lake. Additionally, the nearshore and open waters of Lake George were sampled during storm and nonstorm periods, to assess the impact of stormwater runoff on the trophic conditions of the lake. Runoff from developed areas accounts for 13.6 percent of the annual phosphorus loading to Lake George, which is 15.1 percent of the load to the South Lake and 6.5 percent of the load to the North Lake. In addition, developed areas contribute 28.9 percent of the annual phosphorus load to the study area at the extreme south end of the lake. |
| TOOLS FOR ASSESSING LAKE EUTROPHICATION IN THE PUGET SOUND REGION, WASHINGTON | Robert J. Gilliom | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 32 - 39 | TOOLS FOR ASSESSING LAKE EUTROPHICATION IN THE PUGET SOUND REGION, WASHINGTON | Assessment of eutrophication of lakes in watersheds undergoing development is facilitated by estimates of (1) background phosphorus (P) loading and concentration, (2) present-day P concentrations and amounts and sources of P loadings in excess of background levels, (3) the sensitivity of the lakes to future increases in P loading, and (4) relationships between P concentration and other factors that determine lake water quality. Methods have been developed for making such estimates for lakes in the Puget Sound Region based on data already available for most lakes in the region. Background P loadings were computed from P concentration data for 24 undeveloped lakes in the region using a mass balance model, and predictive relationships were developed from these loadings to estimate background loading for other lakes. The standard error of estimate for background loadings and concentrations averages 25 percent for most lakes in the region. Present-day P loadings were then estimated from measured P concentrations for 28 lakes in basins containing residential land. Differences between present-day and background loading were attributed to land use changes. P loadings from septic systems, computed as the difference between total present-day loading and the sum of background and residential runoff loading, were found correlated with the presence of old homes around the lakes (r2= 0.36). The regression relationship expressing this relation can be used to estimate septic-system loading for other lakes. If necessary, P loading from agricultural land can then be estimated on a lake-by-lake basis as the difference between total present-day loading and the sum of background and both types of residential area loading. Methods are presented for estimating the reliability of all estimates, which varies. These empirical relations allow approximations of the cumulative impact that development has had on P loading and the amounts of loading from generalized land use categories. The mass balance P model also estimates lake sensitivity to future increases in P loading. Finally, predictive relationships were developed between P concentrations and Secchi disk transparency and chlorophyll a concentrations, two key indicators of lake water quality related to eutrophication, based mainly on data for 17 well-studied lakes in the region. |
| FLORIDA LAKES ASSESSMENT: COMBINING MACROPHYTE, CHLOROPHYLL, NUTRIENT, AND PUBLIC BENEFIT PARAMETERS INTO A MEANINGFUL LAKE MANAGEMENT SCHEME | H. L. Edmiston; V. B. Myers | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 25 - 31 | FLORIDA LAKES ASSESSMENT: COMBINING MACROPHYTE, CHLOROPHYLL, NUTRIENT, AND PUBLIC BENEFIT PARAMETERS INTO A MEANINGFUL LAKE MANAGEMENT SCHEME | Numerous indices developed during the last 10 years to quantify the concept of trophic state turned out to be too ambiguous to be useful to lake managers. Based on empirical relationships between various water quality indicators, the most widely used indices use Secchi disk transparency, chlorophyll a concentration, and total phosphorus as a measure of lake trophic state. Indices based on data from north temperate lakes, however, are not directly applicable to Florida lakes. Many Florida lakes are known to be nitrogen rather than phosphorus limited. Florida lakes also commonly have macrophyte problems which are not accounted for by such indices. A series of indices based on Secchi disk transparency, chlorophyll a concentration, macrophyte abundance, total phosphorus concentration, and total nitrogen concentration were developed for Florida lakes. The Secchi disk index serves as a physical measure of trophic state. The public perceives water clarity as an important attribute of lakes, and Secchi disk transparency is a good measure of water clarity. The biological measures of trophic state are based on chlorophyll a concentration and macrophyte coverage. Chlorophyll a concentration is a good indicator of algal populations and macrophyte coverage is related to potential aquatic weed problems. Since phytoplankton and macrophytes compete for similar habitats, Florida's shallow lakes usually do not experience nuisance conditions of both these autotrophs simultaneously. The chemical measures of the trophic state are total phosphorus and total nitrogen concentrations. These elements are the principal nutrients limiting primary productivity in aquatic systems and therefore provide useful information on the nutritional status of lakes. When the lake is primarily phosphorus limited, based on the ratio of total nitrogen to total phosphorus concentration, the phosphorus trophic index is used. If the lake is nitrogen limited, based on the concentration ratio, the nitrogen index is used. Many Florida lakes are not limited by a single nutrient and are relatively well balanced. In this case an average of the nitrogen and phosphorus indices is used to determine the trophic status. The overall trophic state index for a Florida lake is determined by combining the appropriate values obtained from the physical, chemical, and biological indices. Over 570 lakes in the State were ranked by this method. The relative simplicity of the trophic index, combined with its accuracy and reliability, emphasizes its utility in statewide lake management. |
| COMPUTER ASSISTED WATER QUALITY DATA ANALYSIS | Michael W. Mullen; Stephen R. Smith; Richard E. Price; Terry S. Smith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 48 - 52 | COMPUTER ASSISTED WATER QUALITY DATA ANALYSIS | Comparing water quality data with standards, criteria, or management guidelines can be a major part of any water quality assessment. The effort required for manual comparisons of data for a large reservoir or watershed project can become a formidable task. One solution to the problem is to utilize a digital computer in conjunction with appropriate software designed to compare numerical water quality data with Federal and State criteria or standards as well as user-specified management guidelines. Aside from reducing the labor cost of data analysis, more accurate, rapid, and flexible analyses of water quality data can be readily performed. Utilization of such software can also allow a more extensive comparison of water quality data and criteria than would otherwise be possible. A software package of this type has been developed for the U.S. Army Corps of Engineers, Vicksburg District. The program, WATERCHECK, is used primarily in comparing project water quality data with Federal and State standards; a comparison which was not always feasible without the program. The processing of a data set which previously required 2-4 man-days now can normally be accomplished in 1 man-day. WATERCHECK is especially useful for State and regional water quality management organizations responsible for assessment of large amounts of data. User-specified options which allow the data to be compared against criteria or standards for different water use classifications are useful for water resource planning purposes as well as water quality management. |
| APPLICATION OF MULTISPECTRAL DIGITAL IMAGERY TO THE ASSESSMENT OF PRIMARY PRODUCTIVITY IN FLAMING GORGE RESERVOIR | James Verdin; David Wegner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 63 - 68 | APPLICATION OF MULTISPECTRAL DIGITAL IMAGERY TO THE ASSESSMENT OF PRIMARY PRODUCTIVITY IN FLAMING GORGE RESERVOIR | In support of the Bureau of Reclamation effort to manage eutrophication trends in Flaming Gorge Reservoir, Utah and Wyoming, remote sensing studies employing multispectral digital imagery were undertaken. Specifically, the imagery was used to extrapolate point measurements of chlorophyll concentration and light penetration to characterize conditions throughout the reservoir. In 1981 and 1982, aircraft and satellites acquired digital imagery of the reservoir concurrent with surface sampling. Sampling stations were identified within the imagery and the digital values at these points recorded. The surface measurements of chlorophyll and light penetration were regressed against the digital image values to obtain predictor equations for these indicators of primary productivity. The equations were then applied to the images of the whole reservoir to obtain maps of the distribution of chlorophyll and light penetration. A unique set of equations was defined for each data-gathering date. The favorable results obtained in the date-specific studies prompted a search of data archives for other dates for which surface sampling and satellite imagery were both available. An atmospheric radiative-transfer model was also obtained to allow for correction of imagery for sun angle and atmospheric effects. This effort served two purposes: (1) to permit development of chlorophyll and light penetration predictor models from as many surface observations as possible, regardless of date of collection, and (2) to permit estimation of reservoir conditions from imagery for which no concurrent surface sampling was available. Seven satellite scenes were processed to estimate and map chlorophyll and light penetration, although concurrent surface sampling data were available for only four of them. The maps produced were used by reservoir managers to follow year-to-year trends in primary productivity. |
| IRON, MANGANESE, AND SULFIDE TRANSFORMATIONS DOWNSTREAM FROM NORMANDY DAM | John A. Gordon; W. Paul Bonner; Jack D. Milligan | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 58 - 62 | IRON, MANGANESE, AND SULFIDE TRANSFORMATIONS DOWNSTREAM FROM NORMANDY DAM | During recent hearings on a unit of the Duck River Project, Columbia Dam and Reservoir, the question “How far downstream can water quality problems related to iron and manganese be expected to occur, and why?†arose. The two most prominantly unknown variables were time-of-travel below the dam and oxidation-precipitation rates. No rates were found for field studies and laboratory rates were either very high or very low. Most laboratory studies involved considerable pH shifts. Since the literature produced little information useful for predicting the oxidation rates of iron and manganese in tailrace streams, a study of iron, manganese, and sulfide kinetics was designed and performed at Normandy Dam, a TVA multipurpose project on the Duck River upstream of the Columbia Dam near Tullahoma, Tenn. The study found that manganese in the Normandy tailrace exists largely in the Mn++form which passes a 0.1μ filter. Only a small percentage of the total manganese is particulate. Mn++is oxidized as a linear function of time-of-travel at a rate of 0.041 mg/l per hour at a pH of 7.1 and a temperature of 17°C. The oxidized Mn precipitate is quickly settled and/or sorbed upon rocks and debris resulting in a a linear loss of total Mn with time-of-travel. The total Mn loss rate is 0.035 mg/l per hour at the previously stated conditions. Precipitation rates in the Duck River below Normandy Dam are as much as 50 times greater than rates determined in laboratory studies. Iron in the Normandy tailrace exists in three forms: particulate, colloidal, and dissolved. Exchange between the colloidal fraction and the dissolved Fe++fraction occurs in the river. The total iron decreases only slightly with time-of-travel in the Duck River. The colloidal fraction will not settle and evidently the particulate fraction is too buoyant to settle. Only 27 percent of the total iron was revoved during 29.5 hours of travel time. The presence of Fe++apparently keeps the S=concentration very low at less than 0.025 mg S=/l both in the lake and the tailrace stream due to formation of FeS which is insoluble. This research was conducted during the time period of June through December 1982. |
| KENTUCKY RESERVOIR ASSESSMENT OF WATER QUALITY AND BIOLOGICAL CONDITIONS | Neil E. Carriker; Mahlon P. Taylor | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 53 - 57 | KENTUCKY RESERVOIR ASSESSMENT OF WATER QUALITY AND BIOLOGICAL CONDITIONS | Spatial and temporal variations in water quality and biological conditions were investigated in the lower 77 miles of Kentucky Reservoir in a series of monthly surveys conducted from February to September 1982. Factors investigated included dissolved oxygen and nutrient dynamics, algal community structure and standing crop, primary productivity, limiting nutrients, and water chemistry. Significant longitudinal and seasonal variations were observed for most parameters. Only minimal variations were observed with depth. Although thermal stratification was not observed, weak dissolved oxygen stratification did occasionally develop. Reservoir hydrodynamics appears to have pronounced effects on water chemistry and algal productivity. |
| POLITICS OF ACID RAIN | A. O. Shingler | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 5 - 7 | POLITICS OF ACID RAIN | |
| USDA PROGRAMS AND NONPOINT SOURCE POLLUTION | Richard D. Siegel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 3 - 4 | USDA PROGRAMS AND NONPOINT SOURCE POLLUTION | |
| EPA'S EMERGING NONPOINT SOURCE ROLE | Rebecca W. Hanmer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 1 - 2 | EPA'S EMERGING NONPOINT SOURCE ROLE | |
| RURAL AMERICA: EMPHASIS ON CLEAN WATER | Willard Bill Phillips Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 8 - 9 | RURAL AMERICA: EMPHASIS ON CLEAN WATER | |
| NUTRIENTS IN CANAL FLOWS TO LAKE HEFNER, OKLAHOMA | Dale W. Toetz | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 21 - 24 | NUTRIENTS IN CANAL FLOWS TO LAKE HEFNER, OKLAHOMA | Lake Hefner is a terminal offset reservoir located in Oklahoma City and used as a water supply lake. The lake is eutrophic and customers frequently complain of tastes and odors in finished water. During 1980 to 1981, water and nutrient budgets were constructed to learn the causes of eutrophication of the lake. Most water and nutrients entered the lake via a 11.6 km canal from the North Canadian River. The loadings were regulated so that flow events in the canal coincided with releases of water from Canton Lake, which is located upstream on the North Canadian River, or when rain fell on its watershed. Discharge and nutrient content were monitored during these flow events. Linear regression of concentration of nutrients on discharge showed soluble reactive phosphorus decreased with increasing discharge rate in both North Canadian and Canton flow events. Ammonia, nitrate, and Kjeldahl nitrogen increased as discharge rate increased only in North Canadian flow events. Canal discharge did not have typical features of stream hydrographs. Therefore, canal discharge may not be usable as an infallible predictor of nutrient concentrations. Estimation of nutrient loading of lakes via canals may of necessity remain highly empirical. |
| WISCONSIN'S LAKES: A TROPHIC ASSESSMENT | Ronald H. Martin | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 17 - 20 | WISCONSIN'S LAKES: A TROPHIC ASSESSMENT | A cooperative program between the Wisconsin Department of Natural Resources and the University of Wisconsin-Madison (UW-MSN) has resulted in the assessment of the trophic condition of approximately 3,000 significant inland lakes in Wisconsin. A sophisticated set of computer programs has been developed by the UW-MSN that locates the lakes that are to be classified, extracts the spectral reflectance values from Landsat digital data for those lakes, and then adjusts the lake data for atmospheric effects. The corrected lake statistics from Landsat data are correlated to measured field parameters collected on a limited number of lakes. Finally, the relationships developed are used to predict the trophic condition of the significant lakes in the State. |
| EVALUATING RESERVOIR TROPHIC STATUS: THE TVA APPROACH | Janice Placke Cox | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 11 - 16 | EVALUATING RESERVOIR TROPHIC STATUS: THE TVA APPROACH | TVA tributary and mainstem reservoirs show generalized differences in morphometry, hydraulics, nutrient loads, and response to nutrient conditions. Neither type of reservoir is comparable to the natural lakes on which classical eutrophication studies have been based. The majority of published trophic state indices and standards (e.g., hypolimnetc dissolved oxygen depletion, Secchi depth, areal nutrient loading rates, in-reservoir phosphorus concentrations) are inappropriate for evaluation of the trophic status of some or all TVA reservoirs. Relative trophic state indices were developed for mainstem and tributary reservoirs using relevant potentiating and response variables. Ranking of the mainstem reservoirs is based on planktonic chlorophyll, macrophyte coverage, hydraulic retention time, reservoir area less than 5 feet deep, annual pool elevation drawdown, and Secchi depth. Ranking of the tributary reservoirs is based on planktonic chlorophyll, total phosphorus and total nitrogen weighted by the N:P ratio, and bioavailable inorganic carbon levels. |
| REDUCING SEDIMENT PHOSPHORUS RELEASE RATES IN LONG LAKE THROUGH THE USE OF CALCIUM NITRATE | Peter R. Willenbring; Mark S. Miller; William D. Weidenbacher | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 118 - 121 | REDUCING SEDIMENT PHOSPHORUS RELEASE RATES IN LONG LAKE THROUGH THE USE OF CALCIUM NITRATE | The effect of injecting different dosage rates of calcium nitrate into the bottom sediments of Long Lake in New Brighton, Minn., was observed in a laboratory study. The purpose of the study was to determine the minimum dosage necessary to reduce phosphorus release rates from the sediments to satisfactory levels. The study included measurement of sediment phosphorus release rates under both aerobic and anaerobic conditions, and evaluated the effect of adding ferric chloride to the sediments along with the calcium nitrate. The addition of ferric chloride was included in the study to determine if the iron available in the sediment was adequate to sorb the PO4-3when oxidized conditions were provided. The study concluded that at least for the short term (90 days), injection of calcium nitrate could eliminate virtually all phosphorus release from the sediments previously releasing phosphorus at a rate of 7 mg P/m2/day, and actually result in the sediments becoming a sink for phosphorus in the water column. The study also concluded that although the addition of iron enhanced the calcium nitrate treatment's effectiveness, similar results could be achieved by increasing the calcium nitrate dose slightly and not adding the iron, which was a more cost-effective alternative. |
| ENHANCEMENT OF INTERNAL CYCLING OF PHOSPHORUS BY AQUATIC MACROPHYTES, WITH IMPLICATIONS FOR LAKE MANAGEMENT | B. C. Moore; H. L. Gibbons; W. H. Funk; T. McKarns; J. Nyznyk; M. V. Gibbons | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 113 - 117 | ENHANCEMENT OF INTERNAL CYCLING OF PHOSPHORUS BY AQUATIC MACROPHYTES, WITH IMPLICATIONS FOR LAKE MANAGEMENT | Observations over a 14-year period at Liberty Lake, Wash., have indicated a close relationship between the seasonal decline of aquatic macrophyte populations and the onset of planktonic Cyanobacteria blooms. Tracer methods, using radiophosphorus, have been employed in laboratory and in in situ experiments to investigate the ability of Elodea canadensis, an important component of the Liberty Lake macrophyte community, to translocate phosphorus from sediments to the open water. Results of these experiments showed good agreement between release rates determined in the laboratory and in situ for senescing macrophytes. Experiments with actively growing Elodea plants indicate some release or leakage of phosphorus from healthy plants. Nutrient budgets and a phosphorus model for Liberty Lake indicate that internal cycling of sediment phosphorus by aquatic macrophytes is an important source of phosphorus to planktonic primary production as well as direct sediment/water exchange. Indeed, in Liberty Lake, it is possible that macrophyte influence on the dynamic cycling of phosphorus in the lake may not only influence, but also control the pattern, timing, and community composition of planktonic production. A conceptual framework that can be applied by lake managers for determining the potential contribution of macrophyte phosphorus cycling in lakes is discussed. |
| BACKGROUND FOR MANAGEMENT OF TROPICAL RESERVOIRS IN PUERTO RICO | Laurence J. Tilly; Jorge R. Garcia | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 106 - 112 | BACKGROUND FOR MANAGEMENT OF TROPICAL RESERVOIRS IN PUERTO RICO | An EPA sponsored lake restoration feasibility study afforded the opportunity to examine the applicability of conventional temperate zone indices and management approaches to tropical Puerto Rican lakes. Major problems in using temperate zone guidelines are anticipated in Puerto Rico because lake events are relatively aseasonal, nitrogen rather than phosphorus may be limiting, heavy rainfall and steep topography result in naturally high loading, and mountainous terrain results in protection from wind driven mixing. Data for 26 lakes were examined; two of these lakes had been studied in detail. Trophic state indices using chlorophyll, nitrate, total phosphorus, transparency, net productivity, and other parameters were calculated and used in lake ranking. Some comparisons with Florida lakes suggest that Puerto Rican lakes receive more nutrients without developing objectionable blooms. We suggest a series of recommendations for study and management of Puerto Rican lakes. |
| THE ROLE OF INTERNAL PHOSPHORUS LOADING ON THE TROPHIC STATUS OF NEW JERSEY'S TWO LARGEST LAKES | Stephen J. Souza; John D. Koppen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 122 - 128 | THE ROLE OF INTERNAL PHOSPHORUS LOADING ON THE TROPHIC STATUS OF NEW JERSEY'S TWO LARGEST LAKES | Under conditions of anoxia, lake sediments will liberate sorbed phosphorus compounds into the overlying water. The magnitude of the sediment-liberated phosphorus load will be a function of the concentration of phosphorus in the sediments, the area of lake bottom overlayed by anoxic water, and the temporal duration of anoxic conditions. In some cases the resulting phosphorus load may be a substantial component of the lake's annual phosphorus budget. This may have serious implications in the restoration and management of such lakes. The importance of internally-generated phosphorus loads in the nutrient budget of New Jersey's two largest lakes, Lake Hopatcong and Greenwood Lake, was assessed. The formation and depth of the thermocline were established from temperature profiles. The volume of the hypolimnion and the area of lake bottom overlayed by the hypolimnion were calculated. Following stratification, water column profiles of total phosphorus and dissolved oxygen concentrations were monitored. These data were used to compute the internally generated phosphorus load. In both lakes, a 10-fold increase in the concentration of total phosphorus was observed following the depletion of oxygen in the hypolimnion. The internally generated load associated with this phenomenon represents 5.9 percent and 29.3 percent of the annual total phosphorus budget of Lake Hopatcong and Greenwood Lake, respectively. The relevance of endogenous phosphorus loading is discussed for each lake in relation to its existing trophic status and future restoration and management. |
| THE INTERACTIONS AMONG DISSOLVED ORGANIC MATTER, BACTERIA, SUSPENDED SEDIMENTS, AND ZOOPLANKTON | Joseph A. Arruda; G. R. Marzolf | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 139 - 143 | THE INTERACTIONS AMONG DISSOLVED ORGANIC MATTER, BACTERIA, SUSPENDED SEDIMENTS, AND ZOOPLANKTON | Lakes and reservoirs in agricultural watersheds are often turbid with suspended sediments. The interactions among suspended sediments, dissolved organic matter, bacteria, algae and zooplankton will continually modify water quality. Our object was to evaluate the effects of dissolved organic matter (DOM) source, bacteria, and suspended sediments on the survival and growth in body length of Daphnia pulex . We grew Daphnia in vitro with different DOM sources (bur oak and hackberry leaf leachate), with and without suspended sediments. Daphnids grown in hackberry leaf leachate, with or without sediments, grew more than those in the corresponding bur oak leaf leachate treatments (P < 0.01). Bacterial density also was higher in the hackberry treatments compared to the bur oak treatments. Daphnids grew more in treatments with DOM plus suspended sediments than in the corresponding treatments without suspended sediments (P < 0.01), although bacterial density was lower in treatments with suspended sediments. Suspensions without daphnids had lower bacterial densities than those with daphnids. This experiment reveals some of the complexity of the interactions among the sediments, DOM, bacteria, and zooplankton that influence water quality. The results may have some applications to lake and reservoir management, particularly the biomanipulation of water and wastewater. |
| LONG TERM EFFECT OF HYPOLIMNETIC AERATION OF LAKES AND RESERVOIRS, WITH SPECIAL CONSIDERATION OF DRINKING WATER QUALITY AND PREPARATION COSTS | Bo Verner | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 134 - 138 | LONG TERM EFFECT OF HYPOLIMNETIC AERATION OF LAKES AND RESERVOIRS, WITH SPECIAL CONSIDERATION OF DRINKING WATER QUALITY AND PREPARATION COSTS | Aeration with the commercially available LIMNO aerator has now been in use for about 10 years. Over 40 aerator units have been installed and successfully operated in nine different projects. From the abundant experience gathered during this relatively long period some examples are chosen to illustrate the efforts on increased mineralization capacity of allochthonous and autochthonous organic material. The ubiquitous eutrophication problems especially degrade water quality in lakes and reservoirs. Excessively produced algal material in the hypolimnetic layer leads to serious anoxia, preventing higher life and aerobic respiration processes. Furthermore, internal recycling processes connected with the metabolic and geochemical cycles of manganese and iron enable the multiple use of recycled phosphorus. All of these processes are possible to control by aeration. On the other hand, necessary treatment for drinking water preparation, such as filtration, flocculation, and chlorination can be reduced if a sufficient oxygen balance is maintained in the hypolimnetic water body. Results are presented from two drinking water reservoirs and some lakes where drastic improvements were observed. |
| THE IMPORTANCE OF SEDIMENT RELEASE IN THE ASSESSMENT OF A SHALLOW, EUTROPHIC LAKE FOR PHOSPHORUS CONTROL | Patricia Mitchell | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 129 - 133 | THE IMPORTANCE OF SEDIMENT RELEASE IN THE ASSESSMENT OF A SHALLOW, EUTROPHIC LAKE FOR PHOSPHORUS CONTROL | Complaints of declining water quality and increasing macrophyte growth resulted in a 3-year study to determine the feasibility of phosphorus control on recreationally important Lake Wabamun, Alberta. All nutrient inputs including groundwater were measured or estimated to assess the importance of each source. A preliminary phosphorus loading calculation suggested that the sediment may supply a large quantity of phosphorus during the annual cycle. Sediment release was estimated using a mass balance approach and by phosphorus analysis of sediment cores taken at biweekly intervals. The mass balance suggested that release occurred in late summer, and represented a gross input that exceeded annual external supplies. This was supported by a decline in non-apatite inorganic phosphorus in cores during the same time. These results led to the conclusion that major phosphorus control projects in the watershed were not warranted. |
| THE EFFECTIVENESS OF BMP'S AND SEDIMENT CONTROL STRUCTURES AND THEIR RELATIONSHIP TO IN-LAKE WATER QUALITY | Forrest E. Payne; Timothy M. Bjork | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 82 - 86 | THE EFFECTIVENESS OF BMP'S AND SEDIMENT CONTROL STRUCTURES AND THEIR RELATIONSHIP TO IN-LAKE WATER QUALITY | Lake Herman is a nitrogen limited, hypereutrophic, shallow (mean depth 1.7m), warm water lake located in Lake County, S.D. The lake has experienced extensive blue-green algal blooms, fish winterkills, and receives a high sediment load. Algal and macrophyte growth has diminished the open water surface area. The predominant land use is agriculture with permanent homes, small businesses, and public recreation areas surrounding the lake's shoreline. On January 13, 1978, Lake Herman and its associated watershed were selected to participate in the U.S. Department of Agriculture and U.S. Environmental Protection Agency sponsored Model Implementation Program. The primary objective of the project was to improve the water quality of Lake Herman by reducing phosphorus, nitrogen, and sediment loads through voluntary application of Best Management Practices (BMP's) and construction of sediment control structures. Approximately 5 years of water quality data from the lake, the tributaries, the outlet, and above and below the BMP's, and the sediment control structures are available from this project. Although the results of t-test analyses indicated that the sediment control structures are reducing the sediment and nutrient load, a corresponding reduction has not been observed in the lake. Therefore, two phosphorus mass budget models were used to predict the phosphorus concentrations in the lake: neither predicted the high phosphorus concentrations observed in the lake. It is assumed that another nonpoint source of phosphorus affects the lake (internal loading from resuspended sediments or aquatic macrophytes). The next step in the Lake Herman restoration project is to dredge selected areas to deepen them and reduce the resuspension of sediments. |
| A SIMULATION MODEL FOR ASSESSING THE SUCCESS OF AGRICULTURAL BEST MANAGEMENT PRACTICES ON SURFACE WATER QUALITY | James Madigan; Douglas Haith; Scott O. Quinn; Jay Bloomfield | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 77 - 81 | A SIMULATION MODEL FOR ASSESSING THE SUCCESS OF AGRICULTURAL BEST MANAGEMENT PRACTICES ON SURFACE WATER QUALITY | A simulation model was used to assess how agricultural practices used to reduce soil erosion, such as no-till cropping, affect the plant nutrient and suspended sediment levels in streams. The model is based on principles developed by the Soil Conservation Service, such as the Universal Soil Loss Equation and the Hydrologic Curve Number Equation. Annual model predictions for discharge and the mass loadings of phosphorus, nitrogen, and suspended sediment compare favorably to actual data collected for Irondequoit Creek, in western New York State during 1980 and 1981. The model was then run, driven by 20 years of meterological data, in order to assess various agricultural Best Management Practices. The effect of selected practices on discharge, nutrient loadings, and sediment loadings is presented. |
| SPATIAL AND SEASONAL PATTERN OF NUTRIENT AVAILABILITY IN LA PLATA LAKE, PUERTO RICO | Jorge R. Garcia; Laurence J. Tilly | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 69 - 76 | SPATIAL AND SEASONAL PATTERN OF NUTRIENT AVAILABILITY IN LA PLATA LAKE, PUERTO RICO | As part of a diagnostic restoration/feasibility study of La Plata Lake in Puerto Rico, we have examined seasonal, vertical, and (some) horizontal patterns of nutrient distribution. The eutrophic state of this reservoir is evidenced in a series of characteristics including epilimnetic (0-4 m) chlorophyll concentrations averaging 15 mg m-3, virtually total absence of dissolved oxygen below 4m, and water hyacinth areal coverage estimated at 40 percent. Annual loadings of nitrogen and phosphorus have been calculated in 107 and 30 gm-2yr-1respectively, giving N:P loading ratios of 8:1. The ratio of N to P in the entire water column crop averaged 10:1 during the study period. The epilimnetic (0-4m) ratio averaged only 6:1. During a stratified dry period N:P ratios as low as 0.9:1 were observed whereas during periods following heavy runoff and lake mixing, the ratios approached values of 16:1. This pattern of inorganic nitrogen distribution suggests surface depletion from assimilation by hyacinths and algae. The suggestions currently being examined are that nitrogen is limiting to primary productivity in the La Plata system and that the principal controller of lake function is the pattern of hydrological events. Any plan to manage this and similar reservoir systems in Puerto Rico must take these factors into account. |
| PROCESS TO IDENTIFY, SCREEN AND PRIORITIZE RURAL WATER RESOURCE AND LAKE REHABILITATION PROJECTS IN ILLINOIS | Thomas E. Davenport | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 87 - 91 | PROCESS TO IDENTIFY, SCREEN AND PRIORITIZE RURAL WATER RESOURCE AND LAKE REHABILITATION PROJECTS IN ILLINOIS | Initial water quality management planning efforts documented that agricultural activities are a major source of pollution in Illinois and mandated the development of plans to control this nonpoint source pollution from agriculture. The most severe agriculturally-related problem is soil erosion and its effects upon the aquatic environment. In Illinois estimated gross erosion exceeds 180 million tons annually, 88 percent of it caused by sheet and rill erosion from cropland. To control agricultural non-point pollution from its source, efficient and effective land management practices and programs must be developed. A fundamental component of this strategy is the identification of specific areas that significantly contribute to the problem, to permit targeting of resources. Illinois Department of Agriculture (IDOA) formed the Soil Erosion and Water Quality Advisory Committee (SEWQAC), which implemented a two-tier targeting system. Local targeting within each district is the first level. The second is statewide targeting to solve problems identified locally that cannot be addressed with local resources. A subcommittee formed by SEWQAC developed a uniform process to identify, screen, and prioritize rural water resource and lake rehabilitation projects within the State. The process provides a uniform and systematic method for local Soil and Water Conservation Districts, ASCS County Committees, and other interested local units of government to identify and compete for funding under three program authorities. Designed to set meaningful State priorities, the system provides equal access for each project to all the program authorities and gives the local county responsibility for identifying and prioritizing its projects. The local Soil and Water Conservation Districts are assisted by a State Association Water Quality Coordinator and assistant funded through an IEPA contract. The process has been successful to date. |
| THE HISTORY OF THE CLEAN LAKES PROGRAM IN TENNESSEE | Fred Van Atta; Greg Denton | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 101 - 105 | THE HISTORY OF THE CLEAN LAKES PROGRAM IN TENNESSEE | The Clean Lakes staff of the Tennessee Division of Water Management have undertaken three separate projects since the inception of the Federal 314 program. The first project was the creation of a Trophic State Index and Priority Ranking System for the publicly owned lakes of Tennessee. This project was completed in 1979. During this inventory of public lakes, attention was drawn to Acorn Lake, a highly eutrophic, highly used public lake located in Montgomery Bell State Park. In 1980, it was decided that the second Clean Lakes project would be a diagnostic/feasibility study of Acorn Lake. The lake was monitored for 23 months in an attempt to discover the source or sources of the nutrients causing the eutrophic conditions at the lake. The Acorn Lake study revealed that a variety of problems within the watershed had created a nutrient sink in the sediments of the lake. Watershed management and lake drawdown were recommended as restoration techniques. While researching this project, the Clean Lakes staff discovered that a significant number of similar public lakes were being routinely artificially fertilized for a variety of reasons. In response to this problem, the Acorn Lake Report contained not only recommendations for Acorn Lake, but also a new Division of Water Management policy against the application of artificial fertilizers in lakes. The third Clean Lakes project, begun in 1982, is a diagnostic/feasibility study with major emphasis on sedimentation and macrophytes of the Upper Buck Basin of Reelfoot Lake. The multiple problems at Reelfoot Lake of siltation, excess macrophyte encroachment, heavy metal and pesticide pollution, and eutrophication have been highly documented, but no one has yet been able to accurately predict the rate of sedimentation in the lake, although it is known to be filling rapidly. The Clean Lakes staff, assisting Dr. J. Roger McHenry of the Agricultural Research Service, U.S. Department of Agriculture, will use cesium-137 dating techniques in an attempt to determine this rate. |
| INCOMPATIBILITY OF COMMON LAKE MANAGEMENT OBJECTIVES | Kenneth J. Wagner; Ray T. Oglesby | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 97 - 100 | INCOMPATIBILITY OF COMMON LAKE MANAGEMENT OBJECTIVES | Lake management involves the formulation of objectives, not all of which are compatible in a given water body. Common objectives such as high quality water supply, suitability for contact recreation, and pleasing aesthetic properties are generally associated with low plankton standing stock, especially as regards phytoplankton. On the other hand, production of fish for food or sportfishing is often impaired by decreases in plankton biomass. Strong correlation has been found between measures of plankton production or standing stock and fish yield. Investigated relationships between phytoplankton, zooplankton, planktivores, and piscivores are consistent with an energy pyramid model of the pelagic food web; greater production at the top of the pyramid is caused by a corresponding increase at its base or through increased internal energy transfer efficiency. Management for higher energetic efficiency is in its infancy and that for greater plankton biomass conflicts with other management objectives. Division of responsibility among various organizations and agencies of government may help achieve single objectives, but impedes progress toward a unified systems approach to lake management. Management objectives may be less conflicting for poorly aerated systems or where fishery management is aimed at certain target species, but serious consideration should be given to potential conflicts during goal formulation. Lake associations and managers should establish management priorities early in their planning processes. Their decisions should use expertise from both fishery and water quality science. |
| MANAGEMENT PLANNING FOR 25 NEW JERSEY LAKES | John Brzozowski; Stephen J. Souza | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 92 - 96 | MANAGEMENT PLANNING FOR 25 NEW JERSEY LAKES | The State of New Jersey has approximately 1,100 lakes of which 345 are publicly owned. Many of these lakes are located in urban-suburban areas with high density residential and commercial land use activities on their watersheds. In 1975, the New Jersey Department of Environmental Protection (NJDEP) initiated a lake management program, inventorying and conducting water chemistry sampling in over 450 of these lakes. Based on these observations, over 30 percent of these lakes were presumed eutrophic. Final determination of trophic status and the development of management plans, however, necessitated more extensive analysis. To accomplish this NJDEP secured a $100,000 Section 314 Lake Classification Grant on Nov. 17, 1979. Of the lakes inventoried, 25 were selected for intensive study. They represent a reasonable cross section of the types of lakes and lake problems in New Jersey. These 25 lakes were ranked on the basis of their trophic status as determined by land use, unit areal loading, methodology, and verified to the extent possible by intensive survey data. Point and nonpoint sources of nutrient loading were identified and quantified. Reduction in nutrient loadings required to improve their trophic status was estimated and management and restoration recommendations to accomplish nutrient reductions described. This evaluation indicated that, for the most part, nonpoint sources related to urban, suburban, and in some cases agricultural stormwater runoff were the major source of nutrient loads to these lakes. The identification of storm water as the major source of loadings to these lakes is timely since New Jersey has just finalized new storm water quality management regulations. |
| LONG-TERM EVALUATION OF THREE ALUM TREATED LAKES | Paul J. Garrison; Douglas R. Knauer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 513 - 517 | LONG-TERM EVALUATION OF THREE ALUM TREATED LAKES | Alum treatment of lakes has been found to be a generally effective method for reducing P concentrations in lakes over a period of 2 to 3 years after treatment. However, the long-term benefits of lake alum treatment in most cases have not been determined. In this study, three Wisconsin lakes treated 9 to 12 years previously were re-examined in 1982 to evaluate the long-term effects of the treatment projects. Results indicated that many years after treatment P levels in all three lakes remained lower than before the lakes were treated. Horseshoe Lake, the first U.S. lake treated with alum in 1970, was more eutrophic in 1982 than immediately after treatment but is still much improved over pretreatment conditions. The reduced levels of phosphorus in 1982 compared with before the alum treatment, indicate the alum layer is preventing the migration of phosphorus from the deep sediments. The 1982 phosphorus concentrations in the hypolimnion of Snake Lake are similar to levels experienced following the 1972 treatment despite continued input of stormwater runoff to the lake. While the previous two lakes are dimictic, Pickerel Lake is a polymictic lake. The increased mixing action has redistributed much of the alum toward the center of the lake. The alum treatment appeared to have little effect on the internal phosphorus dynamics of the lake. |
| MINNEAPOLIS CHAIN OF LAKES VACUUM SWEEPING AND RUNOFF DIVERSION | John B. Erdmann; Norman C. Wenck; Perry Damon | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 508 - 512 | MINNEAPOLIS CHAIN OF LAKES VACUUM SWEEPING AND RUNOFF DIVERSION | The Minneapolis Chain of Lakes, a series of five lakes covering some 445 ha (1,100 acres) within an urban residential setting, is an important recreational and aesthetic resource. The lakes support swimming, fishing, sailing, and canoeing and are almost entirely surrounded by public parkland. However, the lakes exhibit increasing cultural eutrophication. The city of Minneapolis obtained an EPA Clean Lakes grant for demonstrating vacuum street sweeping and first-flush runoff diversion as means for improving the lakes. The project was completed in 1981 following 2 years of monitoring and pilot implementation. In 1979 and 1980, the city regularly vacuum swept streets throughout the Lake Harriet watershed (46 curb-km in 340 ha). During these years, consultants monitored lake quality, weather, runoff flow, and quality in major storm drains to Lake Harriet, and quantity and quality of vacuum swept materials. Runoff data were used to analyze first-flush diversion. Data analysis resulted in estimated runoff coefficients ranging from 0.05 to 0.5 for individual drainage areas throughout the chain. Seasonal patterns of runoff quality were found. Total phosphorus export from the entire watershed of the chain was estimated to average 5.2 kg per hectare (1 pound per acre) in a climatologically normal year (with no allowance for sweeping or diversion). Detailed water and nutrient budgets, including ground water and inter-lake flows, were developed. Runoff and direct precipitation contributed nearly equally to the water budget, but runoff accounted for over 95 percent of phosphorus inputs. Water outflow was predominantly via seepage. Phosphorus retention in the lakes was high, totaling over 90 percent for the whole chain. Vacuum sweeping was found to remove 3 kg phosphorus/curb-km and 69.5 kg organic matter/curb-km (0.26 lb phosphorus/curb-mile and 74 lb organic matter/curb-mile) per sweeping. These are average values: seasonal variations were significant. Weekly sweeping was projected to remove 38 percent of Lake Harriet's phosphorus load. First-flush diversion was analyzed by taking into account the frequency distribution of storms with respect to total precipitation. Diversion was found to be cost effective in some areas and capable of reducing the phosphorus load to Lake of the Isles by 42 percent. A combination of sweeping and diversion throughout the Chain of Lakes watershed was found most cost-effective. This scheme could reduce the whole chain's phosphorus load by 27 percent, at an estimated 10-year cost of $4 million. Predicted transparency increases averaged .77 m (2 ft.) and ranged from .2 m to 1.9 m (one-half to five feet) for individual lakes. |
| RESTORATION OF SEBASTICOOK LAKE, MAINE, BY SEASONAL FLUSHING | Chet Rock; David Courtemanch; Thomas Hannula | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 502 - 507 | RESTORATION OF SEBASTICOOK LAKE, MAINE, BY SEASONAL FLUSHING | During the past century, increased fertilization and the resultant algal and macrophyte growths have severely impaired the quality and use of many lakes throughout the world. A notable case has been the deterioration of Sebasticook Lake. The lake began showing signs of cultural eutrophication in the early 1950's. By the late 1960's it had become hypereutrophic and has remained in that condition despite remedial efforts. Currently a major effort to restore the lake has been undertaken by the State of Maine, U.S. Environmental Protection Agency, U.S. Department of Agriculture and local communities. Estimates of annual external phosphorus loading range from 3,900 to 11,800 kg with an estimate of 9,000 kg considered as the most accurate estimate of the current load. Sources include 2,300 kg and 2,200 kg from the towns of Dexter and Corinna respectively, and 4,500 kg from nonpoint sources of which 85 percent is culturally generated from farmland. Using a mass balance model it is estimated that an annual external load of 4,500 kg of total phosphorus would maintain the lake at a desired concentration of 15 μg/l and suppress the chronic algal blooms. Strategy to control external sources includes advanced wastewater treatment to reduce the loading from Dexter and Corinna to 300 kg and 700 kg, and improved farm practices to reduce nonpoint sources to 3,500 kg. Since the recycle of phosphorus from the lake sediments is estimated to contribute 6,900-9,900 kg into the water column annually, control of internal recycling was also imperative. Because of the large size of Sebasticook Lake (1,798 ha) the most promising means to reduce internal phosphorus was to alter the flushing regime of the lake. Epilimnetic phosphorus reaches peak concentration during late summer stratification. At that time, the lake volume is reduced by one half, decanting the phosphorus rich epilimnetic water. Refill of the lake does not commence until the following spring when phosphorus-poor melt water is available. Drawdown of the lake is accomplished through constructing a 4-meter deep canal and gate structure at the outlet. Initial trials of the structure were estimated to export about 4,200 kg of phosphorus annually. |
| RESPONSES OF WETLAND VEGETATION TO WATER LEVEL VARIATIONS IN LAKE ONTARIO | Wolf-Dieter N. Busch; Lynn M. Lewis | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 519 - 524 | RESPONSES OF WETLAND VEGETATION TO WATER LEVEL VARIATIONS IN LAKE ONTARIO | Water level fluctuations, a naturally occurring phenomena in the Great Lakes, cause a continuing rejuvenation of lake-influenced wetlands. Two Lake Ontario wetlands (Campbell and Sage Creek Marshes) were mapped for 1 ft. contour intervals and habitat-vegetation type. Historical habitat/vegetation conditions were evaluated through interpretation of aerial photography. The photography was selected to represent water levels different from the current. Habitat types defined at Campbell Marsh and their most important herbaceous species include: (1) narrow-leaved persistent emergents, Typha glauca; (2) aquatic bed, Ceratophyllum demersum; (3) grass sedge, Calamagrostis canadensis; (4) scrub/shrub, Cornus spp; and (5) flooded deciduous forest, Fraxinus spp. Habitat types defined at Sage Creek Marsh and their most important herbaceous species include: (1) narrow-leaved nonpersistent emergent, Sparganium eurycarpum; (2) broad-leaved nonpersistent emergent, Pontederia cordata; (3) aquatic bed, Elodea canadensis and (4) grass sedge, Calamagrostis canadensis . Computerized data analysis showed that vegetation types occured within rather distinctive elevational ranges. As water levels changed, the area of the various habitat types changed, adjusting to both the new water depth and to the size of the area at that depth. In Sage Creek Marsh a large area of narrow-leaved nonpersistent emergents was lost as water levels increased. The greatest loss in Campbell Marsh occurred to persistent emergents; however, this loss did not have a linear relationship to annual mean water depth. |
| PREDICTION OF LAKE RESPONSE TO INDUCED CIRCULATION | Robert A. Pastorok; Thomas M. Grieb | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 531 - 536 | PREDICTION OF LAKE RESPONSE TO INDUCED CIRCULATION | The outcome of any lake restoration project depends on numerous variables: e.g., lake morphometry, initial water quality, composition of the biological community, and engineering specifications of the restoration technique. Consequently, a variety of lake responses to restoration attempts can be expected, ranging from complete success to at least partial failure. For example, artificial circulation has improved water quality in many cases, but has often caused adverse ecological impacts, such as increased turibidity or nuisance algal blooms. The benefits of lake restoration can be realized only through accurate prediction of lake responses to alternative management schemes or experimental manipulations. Numerical classification of previous case history data can be used to enhance this predictive capability and to refine lake restoration techniques. By applying Mulitple Discriminant Analysis to case histories of artificial circulation, we defined the critical attributes of a successful restoration project. For each response parameter (e.g., dissolved oxygen, algal density, pH), the initial objective was to maximize separation of lake restoration groups (i.e., successful or unsuccessful) by differentially weighting individual morphometric and mixing-system variables in a discriminant function. When adequate discrimination is obtained, the discriminant function can be used to predict the response of a lake based primarily on physical attributes of the lake (area, volume, depth) and the aeration system (air release depth, air flow rate). |
| THE EFFECTS OF SHOREZONE DEVELOPMENT ON THE NATURE OF ADJACENT AQUATIC PLANT COMMUNITIES IN LAC ST. LOUIS, QUEBEC | T. C. Meredith | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 527 - 530 | THE EFFECTS OF SHOREZONE DEVELOPMENT ON THE NATURE OF ADJACENT AQUATIC PLANT COMMUNITIES IN LAC ST. LOUIS, QUEBEC | The island of Montreal is part of an archipelago at the confluence of the Ottawa and St. Lawrence Rivers. The mixing of waters from two watersheds, the diversity of channel profiles, substrata, and natural riparian communities, and the great length of shoreline give the area a marked biotic richness and high rate of primary productivity. Longstanding public concern over deteriorating water quality and increasing flood hazard has prompted a comprehensive evaluation of the area's aquatic resources by the provincial government. However, these studies have tended to focus on large scale engineering problems and proposals. Urban expansion and the associate pressures on waterfront land have had a persistent and marked effect on the riparian ecosystem. The loss of upland nesting sites, for example, has rendered much of the area sterile to several duck species. The effects on the aquatic community are less clear. This study was undertaken to determine the effects of shorezone development on the communities of aquatic macrophytes in adjacent areas. It entailed the study of 24 paired sites, one site in each pair being off developed shore, the other site being off nearby natural shore. Twenty-two macrophyte species were recorded in all, with Vallisneria americana, Elodea canadensis, and Ceratophyllum demersum being by far the most abundant. Samples taken off natural sites were significantly higher in average species richness and average biomass values than those taken off developed shore. Differences in profile, substratum, and water quality were assessed as possible causes and it is concluded that changes in depth and perhaps the removal of natural substratum are most likely to have been significant factors. The consequences of the observed changes in terms of habitat utility for aquatic fauna are discussed briefly. |
| LIMITING NUTRIENT FLUX INTO AN URBAN LAKE BY NATURAL TREATMENT AND DIVERSION | William D. Weidenbacher; Peter R. Willenbring | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 525 - 526 | LIMITING NUTRIENT FLUX INTO AN URBAN LAKE BY NATURAL TREATMENT AND DIVERSION | The 48 hectare Lake Josephine was being impacted by urban stormwater runoff flowing directly into the lake from 237 hectares of its 341 hectare watershed. Runoff from 90 hectares — or 37 percent — of this direct drainage area was diverted to a 12 ha wetland treatment system for pretreatment prior to its discharge into Lake Josephine. The first year three monitors revealed the treatment system had removal efficiencies of 62 percent for total phosphorus, 69 percent for orthophosphorus, 48 percent for total Kjeldahl nitrogen, and 79 percent for total suspended solids. Three-year average water quality data from the lake itself was also compared to data obtained for 3 years prior to the diversion. The comparison revealed that after the diversion, total phosphorus concentrations decreased from .092 to .058 mg/l, total Kjeldahl nitrogen concentrations decreased from 1.25 mg/l to .7 mg/l, ortho-phosphorus concentrations decreased from .038 mg/l to .03 mg/l, and Secchi depth transparency increased from 3.83 meters to 5.0 meters. |
| GRASS ROOTS LAKE AND WATERSHED MANAGEMENT ORGANIZATION | Robert Burrows; John D. Koppen | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 482 - 486 | GRASS ROOTS LAKE AND WATERSHED MANAGEMENT ORGANIZATION | Greenwood Lake is a 777 ha lake in the suburban New York metropolitan area. The lake lies in New York State (Orange County) and New Jersey (Passaic County) and comes under the jurisdiction of both States. The 6,000 ha watershed is 80 percent forested and 17 percent in residential land use. Greenwood Lake is a headwater of the Wanaque River in the Passaic-Hudson River Drainage Basin. The lake experiences heavy recreational use including boating, fishing, and swimming. Over the course of the last 30 years the lake's water quality has declined appreciably and recreational usage has dropped as a result. Historically, many different citizens organizatons have been formed to address the problems of the lake then gradually died. One major problem with maintaining an active and viable organizaton to coordinate and implement lake management activities on the lake is that the lake is in two States. Although a single lake and a single watershed, local parochial interests prevented coordinated action. In 1979 a group of citizens from New York and New Jersey formed the Greenwood Lake Watershed Management District, Inc., as a bistate committee to address problems of Greenwood Lake. Accepted by the States of New Jersey and New York as a responsible political organization, the GLWMDI applied for and received a grant under Sec. 314 of the Clean Water Act to carry out a lake restoration and watershed management study on Greenwood Lake. The GLWMDI has a 30-member board of directors, an executive director as chairman, and several hundred members. Throughout the 314 study volunteers contributed up to $100,000 worth of hands-on, in-kind services associated with the study. This contribution served as the matching funds needed to obtain the grant. Throughout the 4 years of its existence, the GLWMDI has unified the people in the basin into a powerful action-oriented organization with the welfare of the lake as its primary goal. |
| SMALL LAKES SYMPOSIA PROGRAMS | Virginia M. Balsamo | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 478 - 481 | SMALL LAKES SYMPOSIA PROGRAMS | Lake conservation begins with grass roots efforts recognizing the needs of the area. The following help foster awareness and effective lake conservation programs: (1)stream cleanups create public awareness and provide case studies to help others; (2) lake conservation symposia at local colleges allow speakers to address the lake conservation needs of local communities; (3) collections of lake resource materials for a local library provide easy citizen access to information; (4) a core contact list of local people most active in lake conservation can be circulated to encourage participation at lake conservation activities; (5) a file of names and addresses of all people interested in the lake community aids their notification of all events; and (6) educational projects for youth groups broaden public awareness of lake problems. Citizens should be encouraged to contact their local Extension Office, Soil & Water District, Health Department, Planning Office, Soil Conservation Service, and other citizens for assistance and advice in lake conservation projects. These efforts which have been implemented in northeastern Illinois are applicable wherever lake conservation is a matter of concern and interest. |
| VOLUNTEER LAKE MONITORING: CITIZEN ACTION TO IMPROVE LAKES | Donna F. Sefton; John R. Little; Jill A. Hardin; J. William Hammel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 473 - 477 | VOLUNTEER LAKE MONITORING: CITIZEN ACTION TO IMPROVE LAKES | Citizen activists participate year after year in the Illinois Volunteer Lake Monitoring Program—providing their own boating equipment and collecting data at least twice monthly from May through October. Over two thirds of the volunteers who started in 1981 continue to be active. The program was initiated by the Illinois EPA in 1981 to help citizens make more informed decisions about lakes' use, protection, and management. Citizens are trained to measure Secchi disk transparency and total depth and record field observations in a systematic manner at designated sites. Secchi disks, special data reporting forms, and postage paid envelopes are provided by the Agency. Morphological data and assessment information are also collected for the lake and watershed. The sampling data are computerized and a statewide summary report is prepared. As resources permit, individual lake reports are also prepared which incorporate physiochemical data obtained under the Agency's Ambient Lake Monitoring Program and include general recommendations for lake protection and management. The program has been very successful: 141 volunteers participated in monitoring 87 lakes in 1981; in 1983 approximately 240 volunteers are scheduled to monitor 160 lakes. The program provides the volunteers with current data on their lake and how its transparency compares to other lakes in the State. It also provides a historic data base for determining seasonal and long-term trends in lake quality. The volunteer monitoring program has resulted in implementation of lake protection/restoration measures for several lakes. Federal, State, and local agencies have used the data collected to help assess the severity of water quality impacts from agricultural runoff and target resources for water quality benefits. Volunteer data have helped document water quality problems, point out critical areas most responsible for water quality degradation, guide the implementation of lake protection/management techniques, and evaluate their effectiveness. |
| LAKE ASSOCIATIONS AND THEIR ROLE IN THE MASSACHUSETTS CLEAN LAKES PROGRAM, 1983 | Richard Gelpke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 487 - 490 | LAKE ASSOCIATIONS AND THEIR ROLE IN THE MASSACHUSETTS CLEAN LAKES PROGRAM, 1983 | In 1983 the Massachusetts Division of Water Pollution Control began administering a program of matching grants to municipalities for lake studies and cleanup/restoration activities. Municipalities proposed various projects on 40 lakes and ponds and 35 were able to generate the local match. In some cases lake associations assisted in the process. No correlations were found to exist between cities/towns, their population or economic characteristics and the presence or absence of an association, the size or trophic status of a water body. Apparently lake associations are individual or small group efforts but are not particularly a response to identifiable, repetitive stimuli. It is likely they result from personal, social, and historical factors that are hard to quantify. |
| METHODS AND TECHNIQUES OF MULTIPLE PHASE DRAWDOWN—FOX LAKE, BREVARD COUNTY, FLORIDA | Robert J. Massarelli | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 498 - 501 | METHODS AND TECHNIQUES OF MULTIPLE PHASE DRAWDOWN—FOX LAKE, BREVARD COUNTY, FLORIDA | Multiple phase drawdowns have been suggested as a possible restoration technique for controlling the aquatic weed Hydrilla and for consolidating sediments. Brevard County, in cooperation with the Florida Game and Freshwater Fish Commission, implemented such a program in 1979-80. Fox Lake is a small 44.5 ha (110 acre) freshwater lake in Brevard County on Florida's east coast. This lake, the location of a major regional park, had become unusable to boaters and fishermen due to an excessive growth of Hydrilla. In addition to the Hydrilla, the lake had minimal fish and wildlife benefits due to a thick layer of unconsolidated muck. While the use of proper technique is important, the restoration of Fox Lake required methods which insure full community support, and the cooperation of other agencies and local elected officials' and public involvement are necessary. Techniques must be flexible enough to meet unforeseen or changing conditions. For example, during the Fox Lake drawdowns, lake conditions required innovations such as air boat pull plows and amphibious craft. The Fox Lake project demonstrated that lake restoration projects with maximum and innovative use of local resources can be completed with minimal impacts on local government budgets. |
| CONTROL OF ALGAL BIOMASS BY INFLOW NITROGEN | Eugene B. Welch; Mark V. Brenner; Kenneth L. Carlson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 493 - 497 | CONTROL OF ALGAL BIOMASS BY INFLOW NITROGEN | Dilution water has entered Moses Lake since 1977, usually in amounts exceeding 100 106m3, which has amounted to exchange rates of around 10 percent day-1in 8 percent of the lake volume nearest the input. The principal cause for the marked reduction in algal biomass and increased transparency, prior to the Mount St. Helen's ashfall, was the dilution of inflow concentrations of NO3. Average summer chlorophyll a was closely correlated with flow-weighted mean inflow NO3. Increased NO3-N:SRP in undiluted inflow water following the ashfall caused P limit growth in the lake. Increased dilution water input in 1982, compared to the 2 post-ash years, reduced inflow NO3to biomass-controlling levels in spite of continued high ratios of soluble N:P in the lake. Dilution water was pumped to previously undiluted Pelican Horn in 1982 at a rate of 1.4 m3s-1during July through August. Algal biomass was reduced largely because of cell washout, because undiluted water was pumped after July, but chl a actually increased as a result of increased N availability to previously N-deficient cells. Transparency remained at the same low levels (0.4 m) that existed prior to dilution due to large amounts of nonalgal turbidity, which may not improve even if low NO3water is added and sewage effluent is diverted. |
| MICHIGAN LAKE & STREAM ASSOCIATIONS, INC. THREE RIVERS, MICHIGAN | Donald Winne | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 491 - 492 | MICHIGAN LAKE & STREAM ASSOCIATIONS, INC. THREE RIVERS, MICHIGAN | The history, objectives, and operation of the Michigan Lake & Stream Associations, Inc., is reviewed. This paper details the steps in forming a State association, including the original motivation and the legal problems involved. |
| CAN A MICROCOMPUTER HELP THE MANAGER OF A MULTIPURPOSE RESERVOIR? THE EXPERIENCE OF LAKE COMO | G. Guariso; S. Rinaldi; R. Soncini-Sessa | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 575 - 579 | CAN A MICROCOMPUTER HELP THE MANAGER OF A MULTIPURPOSE RESERVOIR? THE EXPERIENCE OF LAKE COMO | A synthesis of a 5-year study on the efficient regulation of Lake Como in Northern Italy is presented. Its main result was the proposal of a new operating rule for the lake, which has been implemented on a microcomputer. This has been operated daily for 1 year and a first evaluation of the impact of this innovation on the lake manager's attitude is briefly outlined. |
| COMPREHENSIVE MONITORING AND EVALUATION OF THE BLUE CREEK WATERSHED | Thomas E. Davenport | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 570 - 573 | COMPREHENSIVE MONITORING AND EVALUATION OF THE BLUE CREEK WATERSHED | Initial water quality planning efforts documented that agriculture activities are a major source of pollution in Illinois. The most severe agricultural related problem is soil erosion resulting in sedimentation. In Illinois, estimated gross erosion exceeds 180 million tons annually, with 88 percent from cropland. Illinois Environmental Protection Agency in cooperation with various U.S. Department of Agriculture agencies evaluated the water quality impacts of resource managment system implementation under the ACP Special Water Quality Project in the Blue Creek Watershed. The physical, biological, and chemical characteristics of the Blue Creek Watershed Lake have been studied since 1979. A comprehensive monitoring network for the entire Blue Creek Watershed was established to document the basic hydroiogical, meteroiogical, and water quality factors of the project area during 1980. The duration, timing and quantity of nonpoint source pollutants were evaluated within the watershed. The monitoring program was designed to link water quality to what is happening on the land. To understand the processes of soil erosion and nutrient/sediment transport and to draw meaningful conclusions about land use effects, focus was given to sources and movement from sources to the lake outlet. This evaluation integrated reservoir sedimentation surveys, lake water quality monitoring, biological monitoring, water quality monitoring at stream gauging stations and small field sites, a channel dynamics study, and a computerized gross erosion estimate. The stream gauging station and field site monitoring were event-oriented sampling to supplement the baseline monitoring on the stream network and in the lake. There were obvious seasonal and spatial trends exhibited by several physical and chemical parameters within the lake and watershed. In Illinois, erosion control is being used as a surrogate for sediment control because sediment control is less amenable to quantitative analysis. This reflects the current lack of knowledge concerning sediment origin, transport, deposition, and control technology. Integration of source and sediment budget studies with realistic concepts of storm runoff production results from this project will clarify some aspects of the interrelationships between gross erosion and water quality impacts. |
| A SCREENING METHODOLOGY FOR THE SELECTION OF URBAN LAKES' ENHANCEMENT | Carla N. Palmer; Martin P. Wanielista; Russell L. Mills; Gilbert Nicholson; Robert Haven | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 564 - 569 | A SCREENING METHODOLOGY FOR THE SELECTION OF URBAN LAKES' ENHANCEMENT | In the summer of 1983, 106 lakes in the city of Orlando, Fla. were considered in a selection process to determine which most needed restoration in the City's Lake Enhancement Program. The existing lake systems were thoroughly investigated with regard to historical water quality data; existing water quality data; current public uses; visual, physical, and chemical condition; the drainage basins; the stormwater structures and management controls; as well as surface color aerial and false color infarared aerial photometric reconnaissance. These were analyzed to provide an objective screening process to determine a discrete set of lakes, approximately four to six, which may be top candidates for a pilot lake project. This paper describes the screening process. |
| VANCOUVER LAKE: DREDGED MATERIAL DISPOSAL AND RETURN FLOW MANAGEMENT IN A LARGE LAKE DREDGING PROJECT | Richard Raymond; Fred Cooper | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 580 - 585 | VANCOUVER LAKE: DREDGED MATERIAL DISPOSAL AND RETURN FLOW MANAGEMENT IN A LARGE LAKE DREDGING PROJECT | The restoration of Vancouver Lake required the dredging of 6.5 106m3of material from the Lake, the construction of 17 km of land based retaining dikes to enclose 180 ha of disposal area, and the disposal of nearly 3 106m3of material in the lake to form an island. The requirement that all dredge return flow be returned to the lake necessitated careful control of dredging activity and the imposition of several design and operation features to control the quality of the return flow water. Some of the measures used included multiple, or settling basins, extended wier length to reduce crest height, silt curtain enclosures around dredge disposal site outfalls, rapid alteration of dredge disposal sites, and careful monitoring of dredging activity and return flow quality. These measures enabled the project to be completed with minimum delay, ahead of schedule, and with no serious violation of water quality standards. Observations and data on water quality conditions during construction and the efficacy of specific dredging and sediment containment methods will be described. |
| GIBRALTAR LAKE RESTORATION PROJECT — A RESEARCH AND DEVELOPMENT PROGRAM FOR EVALUATION OF THE TRANSPORTATION (DREDGING) OF CONTAMINATED SEDIMENTS | Raymond E. Spencer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 599 - 604 | GIBRALTAR LAKE RESTORATION PROJECT — A RESEARCH AND DEVELOPMENT PROGRAM FOR EVALUATION OF THE TRANSPORTATION (DREDGING) OF CONTAMINATED SEDIMENTS | Santa Barbara has had a leadership role in the field of environmental concerns for over 50 years and for that reason had a concern of the total environmental considerations involved in the transportation (dredging) of contaminated sediments from their main water supply reservoir, Gibraltar Lake. Silt from the adjacent watershed has been reducing the City's available water supply (equal to 360,000 cu yds) annually with the total of approximately 22,000,000 cu yds of silt currently contained within the reservoir. This R&D Program was sponsored in part by the U.S. Environmental Protection Agency (EPA) to evaluate the removal of mercury contaminated silt using an air pump to a containment area and to assist other responsible agencies in evaluating this method when reviewing other similar projects in the future. |
| DREDGING FOR CONTROLLING EUTROPHICATION OF LAKE KASUMIGAURA, JAPAN | Ken Murakami | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 592 - 598 | DREDGING FOR CONTROLLING EUTROPHICATION OF LAKE KASUMIGAURA, JAPAN | Lake Kasumigaura, the second largest lake in Japan, is an extremely eutrophicated lake, yet is one of the most important water resources around the Tokyo metropolitan area. It is a shallow lake with an average depth of 4 m. Nutrient exchange between the lake water and sediments was found to be the major factor affecting the nutrient balance within the lake. Therefore, it was decided to carry out dredging of sediments along with other measures to control eutrophication of the lake. To dredge fluffy sediments on the top layer effectively and to avoid excessive disturbance of the sediments, a special purpose dredge equipped with the Oozer system was built, and later, a modified version was constructed. The engineering aspects of dredge efficiency are summarized in the paper based on the 5-year experience. |
| DREDGING AND DREDGED MATERIAL DISPOSAL TECHNIQUES FOR CONTAMINATED SEDIMENTS | Raymond L. Montgomery | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 586 - 591 | DREDGING AND DREDGED MATERIAL DISPOSAL TECHNIQUES FOR CONTAMINATED SEDIMENTS | Significant advances have been made in recent years on dredging equipment, operating techniques, and disposal methods for contaminated sediments. Preliminary guidance is available for selecting dredges and operational techniques to minimize resuspension of contaminated sediments during dredging. This is important since research results have indicated that most contaminants are attached to the clay-sized particles and natural organic solids found in lakes. Detailed guidance is available for designing dredged material containment areas based on the settling and physical properties of sediments. A modified elutriate test has been developed to predict levels of both dissolved and particulate associated contaminants in containment area effluents. This test can be used to determine the need for effluent treatment. Guidelines are available for designing treatment systems to clarify the effluent from containment areas. This paper provides information on selecting dredging equipment and operational techniques to minimize sediment resuspension, design of containment facilities, and chemical treatment of containment area effluent to improve suspended solids removal. |
| REVIEW OF DESIGN GUIDANCE ON HYDRAULIC DESTRATIFICATION | J. P. Holland | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 549 - 551 | REVIEW OF DESIGN GUIDANCE ON HYDRAULIC DESTRATIFICATION | Two general methods exist for artificially destratifying an impoundment: (a) pneumatic destratification using compressed air jets, and (b) hydraulic destratification using water jets. Results from laboratory parametric investigations of hydraulic destratification are presented for a variety of test conditions. A practicable limit of destratification, the 80 percent mixed state, was identified and regression analysis used to define the time required for development of this 80 percent mixed state in terms of reservoir geometry, stability, and pumping rates. Results of the regression analysis showed the dimensionless mixing time to the 80 percent mixed state to be a function of a “destratification†densimetric Froude number. The use of these results in a design procedure is discussed. |
| EFFECTS OF AERATION ON LAKE CACHUMA, CALIFORNIA 1980–1982 | John R. Boehmke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 542 - 548 | EFFECTS OF AERATION ON LAKE CACHUMA, CALIFORNIA 1980-1982 | Lake Cachuma, Calif., has historically experienced severe hypolimnetic oxygen depletion during summer stratification. To alleviate this problem and improve the water quality of the reservoir, a diffused-air aeration system was installed in May 1981. A limnological study was conducted from April 1980 through November 1982. Results showed a weakening of the stratification, increased oxygen and temperature in the hypolimnion, increased green algae, and increases in the populations of Bosmina and Chironomids. Lake turnover in 1981 and 1982 occurred approximately one month earlier than in 1980. Water quality problems of manganese and hydrogen sulfide were effectively controlled. |
| THOUGHTS ON SELECTION AND DESIGN OF RESERVOIR AERATION DEVICES | Perry L. Johnson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 537 - 541 | THOUGHTS ON SELECTION AND DESIGN OF RESERVOIR AERATION DEVICES | Alternative devices for reservoir aeration are briefly reviewed. It is noted that each device is best suited for particular applications and objectives. It is recommended that care be taken by the designer to select the appropriate device for the particular application. Advantages and disadvantages of the various devices are given along with representative destratification and oxygenation efficiencies. Design considerations are discussed including techniques for sizing units, the effects of inflows and releases, the effects of reservoir stratification, evaluation of aeration impact on the reservoir temperature regime, and the possible development of nitrogen supersaturation. |
| ENHANCEMENT OF RESERVOIR RELEASE QUALITY WITH LOCALIZED MIXING | Jeffrey P. Holland | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 552 - 554 | ENHANCEMENT OF RESERVOIR RELEASE QUALITY WITH LOCALIZED MIXING | Density stratification limits or negates vertical mixing in lakes and reservoirs with the result that vertical strata of decreasing water quality are formed. Releases from the lowest of these strata, the hypolimnion, may be of generally poor quality due to oxygen deficiency resulting from the coupling of limited vertical mixing and hypolimnetic oxygen demand. A simple, cost-effective method to enhance these releases, localized mixing, utilizes the effects of jet mixing to transport high-quality epilimnetic water down to the hypolimnetic withdrawal zone and dilute the release. To effectively enhance downstream release quality, the localized mixing system must produce a jet of sufficient quantity and initial momentum so that it will both penetrate into the hypolimnion and adequately dilute the release. Laboratory investigations showed jet penetration into the hypolimnion to be a linear function of the densimetric Froude number at the thermocline. Dilution was observed to be a function of effective pumping ratios. An example design based on these laboratory results is given. |
| WATERSHED MANAGEMENT: COOPERATION AND COMPROMISE | William K. Norris | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 561 - 563 | WATERSHED MANAGEMENT: COOPERATION AND COMPROMISE | Watershed management activities in Albemarle County and the city of Charlottesville in the Piedmont Region of Virginia have been examined. In recent years these two localities have exhibited an unusual spirit of cooperation and compromise in protecting the area's water supplies. Creation of a unique position of Watershed Management Official, funded equally by both localities, was one of the first steps taken locally in recognizing that watershed management was a continuing process that required the coordination and integration of many diverse activities and recognizing that proper watershed management requires more than best management practices manuals and ordinances; it requires constant site investigations and surveillance of all watershed activities. Protection of existing water supplies is the major goal of watershed management; however, planning for additional and future needs has not been forgotten. Charlottesville and Albemarle County have again taken that necessary first step in planning for the future by providing the mechanism whereby land for a supplemental water supply impoundment and associated buffer area protection zone will be acquired in the near future even though the actual impoundment will not be needed for 20 or 30 years. The aspects and the degree of the cooperation and compromise needed for a successful watershed management program are examined. |
| WATERSHED MANAGEMENT: MODIFICATIONS IN PROJECT APPROACH | Donald R. Urban; Walter Rittall | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 558 - 560 | WATERSHED MANAGEMENT: MODIFICATIONS IN PROJECT APPROACH | A number of pollutants acting either singly or in combination affect lakes and reservoirs. Attention is turning towards nonpoint sources and watershed management as offering a potential for more cost-effective control. Nutrient reductions below 1.0 mg/l from municipal treatment plants come with an extremely high reduction cost factor as a result of increased hardware, operations, and maintenance costs. Several nonpoint source control demonstration projects have been implemented since the passage of PL 92-500. Some were directed at the unknowns surrounding the control of runoff from both urban and agricultural sources. For agriculture there were questions about the agricultural institutional arrangement and the effectiveness of practices. One restriction was the voluntary nature of participation, deemed the only feasible implementation method. Several projects have now been completed and conclusions and recommendations made. The project approach is emerging as an effective method of focusing resources to control identified natural resource problems. Some projects did not meet all objectives because the problem was not clearly defined and early implementation was demanded. A strong relationship exists, suggesting that nutrient reductions may be obtained from watershed treatment, but quantification is still lacking. Other factors influenced the implementation and kept the focus from zeroing in on critical sources and areas, making project evaluation difficult. Modifications in project development and implementation steps will be discussed based on these findings and suggestions made for more efficient management of watershed projects. |
| ILLINOIS SOIL AND WATER CONSERVATION DISTRICTS ACTION PROGRAM FOR LAKE WATERSHED IMPROVEMENT | Harold Hendrickson; Warren Fitzgerald; Roger Rowe | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 555 - 557 | ILLINOIS SOIL AND WATER CONSERVATION DISTRICTS ACTION PROGRAM FOR LAKE WATERSHED IMPROVEMENT | Illinois Soil and Water Conservation Districts (SWCD's) working through the Association of Illinois Soil and Water Conservation Districts (AISWCD) have developed a strategy for nonpoint source pollution abatement which recognizes SWCD priorities and assigns available information, technical assistance, and incentive resources to solving soil erosion and sediment problems in lake watersheds. Elements of that strategy include: (1) SWCD and AISWCD staff field reviews of lake watersheds designated by the Illinois Environmental Protection Agency; (2) classification of watersheds based on watershed resource information and SWCD priorities; (3) encouragement and assistance for SWCD's to work with appropriate local, as well as, state and Federal agencies to solve nonpoint source pollution problems through a local work plan; (4) development of cost efficient land-operator incentives such as the conservation tillage risk share program being used in one lake watershed; (5) encouragement for lake managers and monitors to work through their SWCD to put soil and water conservation practices in the watershed; and (6) reinforcement of SWCD informational and promotional materials to improve lake watershed management. AISWCD has developed an innovative program based on grass roots support for SWCD watershed programs. Benefits of this approach will be projected for other areas, and this will prove useful, particularly for persons in areas experiencing funding reductions. |
| AN EVALUATION OF PIGMENTED NYLON FILM FOR USE IN AQUATIC PLANT MANAGEMENT | Michael A. Perkins | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 467 - 471 | AN EVALUATION OF PIGMENTED NYLON FILM FOR USE IN AQUATIC PLANT MANAGEMENT | Experimental applications of pigmented nylon film were conducted in the Seattle metropolitan area in order to evaluate gas venting characteristics and instalation procedures. The material was highly effective in controlling aquatic plant growth, causing death and decomposition of covered plant materials in 30 to 35 days. Gas entrappment, ballooning, and lifting was observed with unvented material but this was overcome by placing venting slits in the material. A vent slit design of 12/meter2gave the best result. Installation of the film is straightforward and simple. Difficulties encountered with dense plant growth and soft organic sediments are described. |
| ADIRONDACK EXPERIMENTAL LAKE LIMING PROGRAM | Douglas L. Britt; James E. Fraser | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 360 - 367 | ADIRONDACK EXPERIMENTAL LAKE LIMING PROGRAM | An experimental lake liming program in the Adirondack Mountains of New York State—the largest and most comprehensive in the United States—will initially entail neutralizing two acidified Adirondack lakes now devoid of fish. One lake will be limed with CaCO3and maintained in a circumneutral condition. Brook trout will be stocked in the lake, and their survival and growth monitored. The second lake will be treated in a similar manner, but allowed to reacidify during the study period. The project will address (1) renovation and protection of fishery resources threatened or affected by acidification, and (2) the most critical deficiencies in our understanding of the fundamental mechanisms associated with the neutralization of acidified surface waters. Seven activities constitute the core of this experimental program: (1) evaluation and selection of CaCO3treatment strategies; (2) predictions and monitoring of lake reacidification; (3) evaluation of effects of liming on acid lake sediments; (4) evaluation of effects of liming on phosphorus in the water column; (5) evaluation of effects of liming on dissolved organic carbon; (6) determination of temporal and spatial variations in water column chemistry and metal speciation; and (7) determination of biological responses of fisheries, macrobenthos, and zooplankton to liming and reacidification. Data from Canadian and Scandinavian acid lake renovation projects will be analyzed and integrated into the Adirondack study. |
| ONTARIO'S EXPERIMENTAL LAKE NEUTRALIZATION PROJECT: CALCITE ADDITIONS AND SHORT-TERM CHANGES IN LAKE CHEMISTRY | L. A. Molot; J. G. Hamilton; G. M. Booth | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 356 - 359 | ONTARIO'S EXPERIMENTAL LAKE NEUTRALIZATION PROJECT: CALCITE ADDITIONS AND SHORT-TERM CHANGES IN LAKE CHEMISTRY | This paper presents a preliminary analysis of chemical changes associated with the addition of 84 tonnes of fine calcite (mean diameter 9 μm) in dry form during Aug. 11-16, 1983, to Bowland Lake, a remote and highly acidic lake near Sudbury, Ontario. A Canso water bomber was used to apply the calcite to the lake surface. Immediately following liming, the volume-weighted pH had increased from 5.0 to 6.8 and the volume-weighted alkalinity had increased from -0.7 to 3.6 mg/l. The calcite dissolution efficiency was 40 percent by Aug. 18 and 52 percent by Aug. 31. Aerial application with a Canso is a logistically simple way of neutralizing a remote lake when a suitable runway is available nearby. However, the calcite dissolution efficiency may be lower than the expected value of 73 percent because bombing from low altitudes produces locally high concentrations of calcite particles, which may inhibit dissolution. |
| CALCITE DISSOLUTION AND ACIDIFICATION MITIGATION STRATEGIES | Harald U. Sverdrup | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 345 - 355 | CALCITE DISSOLUTION AND ACIDIFICATION MITIGATION STRATEGIES | The dissolution kinetics of a calcite powder sinking in acidified water, and the dissolution kinetics for the long-term dissolution of calcite from the bottom, taking the deactivation into account are studied. The solutions of the differential equations are given as diagrams that can be used to predict the outcome of a treatment, and the calcite utilization. These solutions are shown to be in agreement with observation from lake liming projects. As a consequence of the verified theory, a mitigation strategy can be outlined in terms of meeting neutralization requirements and project economy. This depends on such variables as initial pH, particle size, location of treatment, water depth, and such. The acidification mitigation strategy is defined for (1) lakes and near stagnant waters, and (2) running waters. For lakes and near stagnant waters a strategy is outlined, and criteria for the neutralizing agent given. The Kalkad Calcite Distributor developed as a result is presented. For running waters a strategy is defined, and criteria given for the neutralizing agent and the location of the effort, to optimize the result and its cost. A short presentation of equipment for treating running water is given—The Fluidized Divertion Well, The Slurry Dosing Equipments and The Dry Powder Dosing Apparatus—along with data on their performance. |
| CONSIDERATIONS OF PRUDENCE AND EQUITY FOR PROTECTING LAKES FROM ACID PRECIPITATION | Alfred M. Duda | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 368 - 373 | CONSIDERATIONS OF PRUDENCE AND EQUITY FOR PROTECTING LAKES FROM ACID PRECIPITATION | Deposition of atmospheric pollutants is occurring over much of eastern North America. While evidence exists of long-term reductions in pH and alkalinity of sensitive surface waters and adverse impacts on aquatic life, much of it is circumstantial. Cause and effect relationships have not been substantiated and many scientific uncertainties must be resolved before decisions concerning emissions controls can be made. This paper addresses the issues of information gaps, scientific uncertainties, and risks in making policy decisions to protect sensitive lake resources from acid precipitation. Circumstantial evidence may be all that decisionmakers can realistically expect from science in the short term, and information gaps inevitably will remain. On such an issue of public significance as acid precipitation, a cogent understanding of existing scientific facts and the use of prudence and equity are needed on the part of decisionmakers to ensure that necessary steps are taken in the face of uncertainty to protect sensitive lake resources from acidification. |
| THE LITTORAL ZOOPLANKTIC COMMUNITIES OF AN ACID AND A NONACID LAKE IN MAINE | Mike Brett | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 385 - 388 | THE LITTORAL ZOOPLANKTIC COMMUNITIES OF AN ACID AND A NONACID LAKE IN MAINE | The littoral zooplanktic communities of an acidic and a nonacidic lake in Hancock County, Maine, were studied. Although the lakes are less than 200 m apart and similar in character and physical habitat, average annual pH differs in the two lakes. Fish are absent in the acidic lake while the nonacid lake contains golden shiners (Notetnigonus crysoleucas), brook trout (Salvelinus fontinalis) and rainbow smelt (Osmerus mordax). The zooplanktic community of the acid lake is dominated by the adult and nauphlii of the copepod, Diaptomus minutus, the large cladoceran, Diaphanosoma brachyurum, and the acid water rotifer, Keratella taurocephala . The nonacid lake is dominated by four zooplankters, D. minutus, the caladoceran, Bosmina coregonis, and the rotifers, K. taurocephala and Keratella cochlearis . The density of three species of zooplankton was greater in the acid lake and the density of ten species was greater in the nonacid lake. Notably, the large cladocerans, D. brachyurum, Polyphemus pediculus, and Acroperus harpae, were more dense in the acid lake. In the nonacid lake, the density was higher for the copepods, D. minutus and a cyclopoid, the cladoceran, B. coregonis, and the rotifers, K. taurocephala, K. cochlearis, Keratella sp., Polyarthra remata, Asplanchna sp., and Trichocerca sp. A. Three factors are probably responsible for these differences, (1) biotic changes caused by the absence of fish in the acid lake, (2) oligotrophication resulting from acidification and a shorter flushing time in the acid lake, and (3) toxic effects of acidification. |
| LAKE ACIDIFICATION AND THE BIOLOGY OF ADIRONDACK LAKES: CRUSTACEAN ZOOPLANKTON COMMUNITIES | James W. Sutherland; Scott O. Quinn; Jay A. Bloomfield; Clifford A. Siegfried | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 380 - 384 | LAKE ACIDIFICATION AND THE BIOLOGY OF ADIRONDACK LAKES: CRUSTACEAN ZOOPLANKTON COMMUNITIES | Fifty-five lakes in the Adirondack Mountains of New York were surveyed during 1982 for crustacean zooplankton, rotifers, phytoplankton, and water chemistry. The midsummer surface pH values ranged from 3.60 to 7.25. Lakes were selected in order to have a wide range of morphometry and watershed characteristics. Zooplankton species richness and diversity declined with pH. In lakes with pH less than 5.0, three species tended to dominate the growing season community. A discussion of the zooplankton communities in acidic lakes that have recently been treated with either agricultural limestone or sodium carbonate is included. |
| STUDIES ON THE USE OF LIMESTONE TO RESTORE ATLANTIC SALMON HABITAT IN ACIDIFIED RIVERS | W. D. Watt; G. J. Farmer; W. J. White | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 374 - 379 | STUDIES ON THE USE OF LIMESTONE TO RESTORE ATLANTIC SALMON HABITAT IN ACIDIFIED RIVERS | Liming experiments were conducted using two approaches: instream placements of limestone gravel and headwater lake neutralization with limestone powder. Instream gravel was ineffective at low temperatures and high flows, and required at least 100 tonnes for each m3.s-1of flow to achieve biologically useful pH increases. The Atlantic salmon showed positive responses, but only in the immediate vicinity of the limestone. Headwater lake liming produced high neutralization efficiencies, but, there were rapid fluctuations in river pH's which resulted from the natural stratification and mixing cycles within the lakes, and from rapid flushing due to high runoff volumes. Inverse stratification under winter ice occasionally produced acidic surface layers and dramatic lowering of downstream pH's. Positive responses were obtained from salmon in the lake's outlet stream. The problems of environmental chemistry and logistics seriously limit the practicability of using limestone to mitigate the acidification of Atlantic salmon rivers. |
| CATCH COMPOSITION AND POTENTIAL IMPACT OF BAITED AND UNBAITED COMMERCIALLY FISHED HOOP NETS IN THREE CENTRAL FLORIDA LAKES | Marty M. Hale; Joe E. Crumpton; Dennis J. Renfro | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 320 - 323 | CATCH COMPOSITION AND POTENTIAL IMPACT OF BAITED AND UNBAITED COMMERCIALLY FISHED HOOP NETS IN THREE CENTRAL FLORIDA LAKES | From June 1980 through March 1983, 528 hoop nets fished in Lake George, Little Lake George and Crescent Lake, Fla. were observed, representing 4,356 net-days of fishing. Commercially important species comprised 66.1 percent of the total catch by number while game fish species represented 7.7 percent of the total catch and 23.1 percent of all game fish caught. Initial mortality for all game fish caught in lake hoop nets was 0.4 percent. Hoop nets baited with blueback herring, Alosa aestivalis, or soybean chips caught more commercially important species (4.5/net-day) than unbaited nets (2.3/net-day) and fewer game fish species (0.5/net-day) than unbaited nets (1.6/net-day). Commercially important species comprised 57.7 percent of the total catch in unbaited nets and 89.3 percent of the catch in baited nets. Game fish species comprised 41.5 percent of the catch in unbaited nets and 10.5 percent of the total catch in baited nets. Juvenile black crappie Pomoxis nigromaculatus (< 22.9 cm) comprised 83.0 percent of all game fish caught in unbaited hoop nets while bluegill comprised 74.6 percent in baited nets. The catch rate of all sizes of game fish caught in baited and unbaited nets combined was 1.4/net-day. An estimated 10-20 game fish/hectare/year were caught in commercial nets during the study. Based on our knowledge of standing crop data from Florida lakes, legally fished hoop nets set for catfish apparently had little impact on the game fish populations of these lakes. |
| THE EXPANSION OF THE WHITE PERCH, MORONE AMERICANA, POPULATION IN LAKE ANNA RESERVOIR, VIRGINIA | A. C. Cooke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 314 - 319 | THE EXPANSION OF THE WHITE PERCH, MORONE AMERICANA, POPULATION IN LAKE ANNA RESERVOIR, VIRGINIA | The expansion of the white perch, Morone americana, population in Lake Anna Reservoir, Va., is documented by examining data resulting from several collection methods. White perch data were derived from annual cove rotenone studies, bimonthly gill net and shoreline electroshock surveys, semiweekly intake screen impingement studies and seasonal entrainment and ichthyoplankton tow surveys. The length of the sampling period ranged from 2 to 7 years depending on how long each method had been employed on the Reservoir and when white perch appeared in each collection. An attempt is made to determine the impact of this expansion upon other species of fish in the reservoir and to address future implications. |
| USE OF COLUMBIA RIVER RESERVOIRS FOR REARING BY JUVENILE FALL CHINOOK SALMON AND SOME MANAGEMENT IMPLICATIONS | Gerard A. Gray; Dennis W. Rondorf | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 310 - 313 | USE OF COLUMBIA RIVER RESERVOIRS FOR REARING BY JUVENILE FALL CHINOOK SALMON AND SOME MANAGEMENT IMPLICATIONS | Historical early life history patterns of fall Chinook salmon have been altered by impoundment of the Columbia River. While growth rates remain high, riverine survival has been reduced by impoundment, passage mortality at dams, predation, disease, thermal stress, and possibly, late ocean entry. Late ocean entry may reduce fall Chinook salmon survival by delaying passage through a sequence of habitats (spatial windows) at a time, size, or physiological state (temporal windows) when they are best adapted to that habitat. Extended freshwater residence retards higher growth rates normally associated with entry into the estuary and ocean, and reduces the higher survival associated with increased size. Managers of hatchery and wild stocks must take these spatio-temporal windows into account when evaluating management techniques such as flow manipulation or transportation. |
| DEVELOPMENT OF FISH POPULATIONS AND MANAGEMENT STRATEGIES FOR THE BLENHEIM-GILBOA PUMPED STORAGE RESERVOIRS | David L. Thomas; Quentin Ross; Alan Milton; James M. Lynch | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 324 - 328 | DEVELOPMENT OF FISH POPULATIONS AND MANAGEMENT STRATEGIES FOR THE BLENHEIM-GILBOA PUMPED STORAGE RESERVOIRS | Fish populations in the Blenheim-Gilboa (B-G) pumped storage reservoirs in the Catskills in New York have been studied since the reservoirs were completed in 1973. The reservoir populations developed entirely from the fishes present in Schoharie Creek and from emigrants from Schoharie Reservoir located 2.5 miles upstream. The fish populations of Schoharie Creek were composed primarily of pumpkinseed, rock bass, white sucker, and brown bullhead. Thirty-four species of fish have been collected in the reservoirs. The more common species in the upper reservoir included yellow perch, pumpkinseed and redbreast sunfish. In the lower reservoir, white sucker, carp, brown bullhead and pumpkinseed were common. Differences between the populations in the two reservoirs are attributed to differences in substrate and to loss of shallow water caused by water level fluctuations. Management techniques employed to date include removal of rough fish to enhance gamefish, construction of constant level ponds for sunfish spawning, and stocking of trout for trout fishing. A fourth technique which appears attractive is the stocking of young walleye fry to enhance the walleye fishery. |
| OCCURRENCE AND CONTROL OF TASTE AND ODOR IN SYMPSON LAKE | G. C. Holdren; R. Major Waltman | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 340 - 344 | OCCURRENCE AND CONTROL OF TASTE AND ODOR IN SYMPSON LAKE | For the past few years Bardstown, Ky., has experienced taste and odor problems with its drinking water. The problems originated in Sympson Lake, the raw water source for the city, but the exact cause was unknown; a chemical and biological investigation was undertaken in 1982 to determine the source of the problems. Chemical analysis indicated that Sympson Lake experiences hypolimnetic oxygen depletion during summer stratification. Although manganese concentrations reached high levels, no chemical cause for the taste and odor was found. Algal counts indicated that maximum taste and odor complaints coincided with increases in diatom population, especially Stephanodiscus . The maximum diatom count was only 126 cells/ml, much lower than counts reported to cause problems in previous studies, but no complaints were noted when other algal species predominated. Several different control methods were investigated. Copper sulfate was applied in April 1982 to control diatom population. Athough a decline in diatom counts was noted after the CuSO4application, a concurrent reduction in soluble reactive phosphorus to < 1 μg/l and rising water temperature may have also contributed to the decline. Aeration, alum treatment, nutrient control, and potassium permanganate plus activated carbon were also investigated as control techniques. Alum and activated carbon/potassium permanganate were judged to be both ineffective and expensive. Aeration is relatively inexpensive but would be expected to have little or no effect on the spring diatom bloom. Control of influent nutrients should prove effective, but further study would be required to determine the costs involved. In the meantime, CuSO4appears to be the cheapest and most effective treatment method. |
| A PROBABILISTIC EVALUATION OF INSTABILITY IN HYPEREUTROPHIC SYSTEMS | Daniel G. Burden; Ronald F. Malone | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 335 - 339 | A PROBABILISTIC EVALUATION OF INSTABILITY IN HYPEREUTROPHIC SYSTEMS | Water quality data on six hypereutrophic urban lakes in Baton Rouge, La., have been collected on a regular basis over a 4-year period as part of a cooperative restoration effort by the U.S. Environmental Protection Agency and the city/parish of East Baton Rouge through the Clean Lakes Program. Thirteen water quality parameters were measured during most of the sampling events, including total phosphorus (TP) and dissolved oxygen (DO). Concentrations for TP and DO during the pre-restoration period ranged from 0.136 mg/I to 1.340 mg/I and 0.40 mg/I to 25.30 mg/I, respectively. This observed variability during pre-restoration illustrates the instability present with these systems. Inherent with this instability is the occurrence of water quality problems, such as summer fishkills. A probabilistic approach was developed to describe the inherent variability typical of these systems. The use of a probability density function to estimate overall summer kill risk is also discussed. This technique was applied to one of the smaller lakes in the system to evaluate restoration efforts. Overall projected fishkill frequency was reduced from approximately eight kills per year to one kill in 7 years following restoration. Such approaches can be used in management to evaluate data more readily where standard procedures are time consuming and funds unavailable. |
| FATE OF HEAVY METALS IN STORMWATER MANAGEMENT SYSTEMS | Harvey H. Harper; Yousef A. Yousef; Martin P. Wanielista | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 329 - 334 | FATE OF HEAVY METALS IN STORMWATER MANAGEMENT SYSTEMS | The State of Florida requires that stormwater originating within a new project or development be managed and treated within the boundaries of the development to protect surface waters. Retention and exfiltration systems are the most common management practices. Theoretically these provide complete removal efficiency up to the design capacity since none of the stormwater reaches the receiving water body by direct inflow. The fate of various pollutants once entering these systems is not known, particularly whether heavy metals remain in them locked tightly by a chemical or physical association or slowly disperse outward over a much larger area to other water bodies. Investigations on an 8-year-old stormwater retention facility (1.5 ha) in Orlando, Fla., to define movement of heavy metals into and out of the basin seek to answer these questions. Stormwater runoff has been collected and analyzed from the input pipe for approximately 1 year. In addition, both wet and dry bulk precipitation are being collected to estimate the relative significance of each input source. Forty-five separate 3 cm core samples were collected from within the pond, divided into four sections and analyzed for zinc, cadmium, copper, aluminum, iron, lead, nickel, chromium, and phosphorus as well as moisture and organic contents. Movements of heavy metals from the inlet were estimated using the top 1 cm values. While zinc and lead were removed rapidly from solution near the outfall, other metals such as copper and aluminum were mobile. Deposition of metals correlated highly with the chemical speciation of the metal at the time of input. The role of plants in trapping and removing heavy metals is also under investigation. Although a large portion of the metals seem to remain within the basin, a certain fraction may leave the pond through percolation and groundwater movement. Five multilevel wells installed from the edge of the pond outward monitor downward or horizontal movement. Groundwater monitoring will continue throughout the typically wet summer season. |
| TROPHIC STATE INDICES: RATIONALE FOR MULTIVARIATE APPROACHES | Patrick L. Brezonik | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 441 - 445 | TROPHIC STATE INDICES: RATIONALE FOR MULTIVARIATE APPROACHES | Trophic state indices (TSIs) have been widely used to rank and classify lakes. Applications and limitations of TSIs are discussed, and types of TSIs developed previously are reviewed. An index is a summary statistic, and most trophic indices have been multivariate metrics, reflecting the complexity of the concept of trophic state. A recently developed TSI scheme for Florida lakes is described. This index includes sub-indices for the major physical, chemical, and biological indicators of trophic conditions (Secchi disk transparency, total P and N concentrations, and chlorophyll a levels), which were developed from a data base of 313 lakes. Use of the index to rank Florida lakes and evaluate problem lakes is described. |
| TROPHIC STATE INDICES IN RESERVOIRS | William W. Walker Jr. | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 435 - 440 | TROPHIC STATE INDICES IN RESERVOIRS | Trophic state index systems provide a framework for data summary, interpretation, and communication. Carlson's indices can be viewed as reexpressions of bivariate regression analyses derived from phosphorus-limited, northern, natural lakes. Several studies have shown that lakes or reservoirs which are nitrogen limited and/or have relatively high concentrations of non-algal turbidity tend to deviate in various ways from these regressions. These deviations are “problems†only if misinterpreted but limit the use of the index system for comparisons or rankings within certain regions and/or types of impoundments. Analysis of data from 65 Corps of Engineer impoundments indicates that a classification or index system which incorporates effects of nitrogen and non-algal turbidity would be of more general use in reservoirs. A principal components analysis is used to summarize impoundment response data into two composite variables which explain 93 percent of the variance in the original measurements. The first component is interpreted as a quantitative dimension which reflects the total amounts of nutrients and light extinction in the water column. The second is a qualitative dimension which reflects the partitioning of nutrients and light extinction between organic and inorganic forms. Basically, this system takes advantage of the fact that some of the deviations from a Carlson-type index system are systematic and contain information on the partitioning of nutrients and light extinction. If the objective is a concise summary of water quality data, information on both dimensions provides a more complete description of reservoir water quality than any single composite variable or index. |
| WHO NEEDS TROPHIC STATE INDICES? | Richard Osgood | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 431 - 434 | WHO NEEDS TROPHIC STATE INDICES? | The degree of nutrient enrichment has classically indicated trophic state. Nutrients alone, however, inadequately describe a lake's trophic-dynamic structure. Therefore, trophic state indices are simplifications of a more dynamic process. The specific utility of trophic state indices for their intended uses (classification and ranking by trophic status) is limited by deviant behavior among the indices. Secondary index information may be obtained by examining these deviations. Often, these deviations indicate the nature of nontypical trophic behavior. |
| ASSESSING THE TROPHIC STATUS OF LAKES WITH AQUATIC MACROPHYTES | Daniel E. Canfield Jr.; John R. Jones | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 446 - 451 | ASSESSING THE TROPHIC STATUS OF LAKES WITH AQUATIC MACROPHYTES | We propose that as a first approach the trophic status of natural and artificial lakes having growths of aquatic macrophytes may be assessed by using the total nutrient concentration in the water column (nutrients contained in the macrophytes plus those in the water) in conjunction with existing classification systems. We developed our approach because current approaches for assessing the trophic status of lakes do not adequately classify lakes dominated by aquatic macrophytes. This occurs because conventional sampling and trophic state assessment emphasize conditions in the water and do not consider the nutrients, plant biomass, or organic production associated with macrophytes. Relationships between aquatic macrophytes and other trophic indicators are discussed because changes in macrophyte abundance influence the structural and functional characteristics of lakes. These changes alter perceptions of water quality and overall lake quality. |
| RESTRUCTURING LITTORAL ZONES: A DIFFERENT APPROACH TO AN OLD PROBLEM | Sandy Engel | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 463 - 466 | RESTRUCTURING LITTORAL ZONES: A DIFFERENT APPROACH TO AN OLD PROBLEM | Dense carpets of submersed macrophytes in lakes restrict boating and swimming, limit movement of predator fishes, trap fish fry, and contribute to poor fishing. Eliminating plant beds, although good for boating and swimming, removes the plant cover, habitat diversity, and invertebrates needed to support a sport fishery. Fiberglass screens and selective plant harvesting have proven useful in breaking up continuous stands of plants, reducing summer biomass and stored nutrients, and forming boating lanes. The screens kept areas free of vegetation all summer when placed on the lake bed in spring and rapidly removed plants when spread over them in summer. Selective harvesting created islands of vegetation, gave predator fishes access to young fishes hiding among the remaining plants, and opened bottom areas for the spread of new plant species. Although intended to destroy vegetation, these and other methods can be used selectively and economically to rebuild littoral zones to benefit both people and lake biota. |
| EFFECTS OF MECHANICAL CONTROL OF AQUATIC VEGETATION ON BIOMASS, REGROWTH RATES, AND JUVENILE FISH POPULATIONS AT SARATOGA LAKE, NEW YORK | Gerald F. Mikol | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 456 - 462 | EFFECTS OF MECHANICAL CONTROL OF AQUATIC VEGETATION ON BIOMASS, REGROWTH RATES, AND JUVENILE FISH POPULATIONS AT SARATOGA LAKE, NEW YORK | Experimental mechanical barge/conveyor harvesting conducted in June and August of 1981 and 1982 significantly reduced total plant biomass initially, relative to control areas. Regrowth of the predominant species, Eurasian watermilfoil (Myriophyllum spicatum), reached pre-harvest levels within 30 days after June and August harvestings. Total plant and M. spicatum biomass (g·m-2, dry) in harvested areas peaked later than control area vegetation both years, and was slightly higher. The ratio of the average annual biomass of the harvested area to the control area was the same both years (0.73), despite significant decreases in overall average total biomass in 1982. Similar harvesting resulted in the removal of primarily juvenile fish. Harvesting was conducted in dense littoral zone stands of milfoil (M. spicatum) and curly-leaf pondweed (Potamogeton crispus). The harvesting operation removed primarily bluegill sunfish (Lepomis macrochirus) and to a lesser degree, largemouth bass (Micropterus salmoides), yellow perch (Perca flavescens) and pumpkinseed sunfish (Lepomis gibbosus). Harvesting effectively removed approximately 2-3 percent of the total standing crop of juvenile fish in both June 1981 and 1982, and approximately 2-8 percent in August of both years. |
| AN OVERVIEW OF CHEMICALS FOR AQUATIC PLANT CONTROL | James C. Schmidt | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 453 - 455 | AN OVERVIEW OF CHEMICALS FOR AQUATIC PLANT CONTROL | Scientists' role is to separate fact from fiction to assure that decisions be based upon valid evidence rather than emotions and misinformation. The use of chemicals for aquatic vegetation control is one issue commonly surrounded with fear and uncertainty by the general public, environmental groups, and politicians. This has led to restrictive laws in some States which severely limit or prohibit the application of registered aquatic pesticides. In-lake rehabilitation methods and watershed protection measures have achieved mixed results in controlling lake nutrient concentrations to suitably limit macrophyte or algae growth. For many bodies of water, high quality water is not presently economically or technologically feasible. However, symptomatic treatment of nuisance aquatic plant growth with chemicals or through integrated pest management methods can provide waterways acceptable for recreational and functional use. Historically, the chemicals used for aquatic macrophyte and algae control were sodium arsenite and copper sulfate, respectively. These did pose a threat to the environment from overdose and abuse in attempts to eradicate rather than manage aquatic plant problems. Today's chemicals and application techniques are more selective and sophisticated. Toxicity limits, breakdown times, and tolerances are established prior to EPA registration. Organic herbicides that characteristically degrade in the environment or become biologically inactive have replaced persistent chemicals such as sodium arsenite. Formulated, chelated copper compounds are replacing copper sulfate treatments as a safer, more effective approach. Improved application equipment, techniques using spray adjuvants, and granular formulations have helped overcome problems with drift and uneven distribution. The judicious use of chemicals for aquatic vegetation control is imperative. Loss of any of our limited number of tools for maintaining suitable recreational and functional waterways through regulations imposed by the uninformed could severely limit our ability to achieve future water quality objectives. |
| ECONOMIC RETURNS AND INCENTIVES OF LAKE REHABILITATION: ILLINOIS CASE STUDIES | Krishan P. Singh; V. Kothandaraman; Donna F. Sefton; Robert P. Clarke | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 405 - 411 | ECONOMIC RETURNS AND INCENTIVES OF LAKE REHABILITATION: ILLINOIS CASE STUDIES | Studies were conducted on three eutrophic Illinois impoundments to determine practical and economically viable measures to reduce water quality related use impairments and evaluate the recreational benefits of those measures. As is typical in Illinois, these relatively shallow impoundments were constructed in fertile floodplains draining croplands, have large watershed area to lake surface area ratios, and relatively short retention times. Frequent inflows of nutrient and sediment laden water contribute to problems of hypolimnetic oxygen depletion, algal blooms, dense macrophyte growth, inorganic turbidity, and siltation. Even where the watershed has been controlled to the best practicable extent, runoff waters still carry nutrients in excess of eutrophic loading rates and significant amounts of sediment, and the lake remains eutrophic. Constraints imposed by morphologic, hydrologic, and watershed factors on lake quality were considered in developing an integrated lake/watershed management strategy for each lake to preserve and maximize its use at minimal cost. In-lake techniques such as aeration/destratification, groundwater/surface water blending (dilution), lake shoreline stablization, weed harvesting, and algal control were not found to be palliative measures but essential management tools to preserve the lakes and allow their full development as recreational resources. A recreational benefit assessment was performed for each project using the unit day value methodology recommended by the U.S. Water Resources Council (18 CFR 713, Subpart K, App. 3. 1982). Benefit/cost ratios were determined in two ways: (1) by the ratio of the total discounted benefits to the requested Sec. 314 grant amount, and (2) by the annual recreational benefit divided by the sum of the amortized capital costs and annual operation, maintenance, and repair costs. The recreational benefit assessment procedure appears to provide an excellent tool for evaluating lake management strategies. The technical information developed in these investigations may be applied to numerous other recreational and public water supply impoundments throughout the Nation. |
| THE IMPROVED WATER QUALITY OF LONG LAKE FOLLOWING ADVANCED WASTEWATER TREATMENT BY THE CITY OF SPOKANE, WASHINGTON | Raymond A. Soltero; Donald G. Nichols | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 395 - 404 | THE IMPROVED WATER QUALITY OF LONG LAKE FOLLOWING ADVANCED WASTEWATER TREATMENT BY THE CITY OF SPOKANE, WASHINGTON | Long Lake, Wash., an impoundment of the Spokane River, has experienced high algal standing crop; low water clarity and extensive hypolimnetic anoxia during summer stratification. The City of Spokane's primary sewage treatment plant was shown to be the primary contributor of phosphorus to the reservoir and the major cause of its eutrophic state. To reduce influent phosphorus (P) loading and improve Long Lake's water quality, the city provided advanced wastewater treatment (AWT) with chemical (alum) phosphorus removal in 1977. Monthly mean P load from the AWT plant has decreased approximately 90 percent and the overall load to the reservoir during the growing season (June-October) has declined about 74 percent. Mean post-AWT reservoir algal biovolumes and chlorophyll a concentrations are approximately 60 and 45 percent, respectively, less than pre-AWT values. A phosphorus load-chlorophyll a relationship, based on 5 years each of pre- and post-AWT data, was developed and provided excellent predictions of mean reservoir chlorophyll a concentrations for the growing season. As a result of AWT, Long Lake has changed from a eutrophic to a mesotrophic body of water. In studying the effects of reduced P loading, it was determined that seasonal chemical phosphorus removal (April through October) could be as effective in reducing algal growth in Long Lake as year-around removal. This conclusion was based on the premise that temperature was the primary limiting variable outside the growing season. The city was granted a change in their AWT plant discharge permit and has implemented seasonal chemical P removal with no detrimental effects on the improved water quality of Long Lake. |
| SOIL LIMING AND RUNOFF ACIDIFICATION MITIGATION | Per Warfvinge; Harald Sverdrup | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 389 - 393 | SOIL LIMING AND RUNOFF ACIDIFICATION MITIGATION | A measure often taken and frequently discussed in Sweden is to try to restore the runoff quality from acidified watersheds by soil liming. In Scandinavian acidified soils, where the base saturation often is below 20 percent, the dissolution of calcite will proceed without significantly improving runoff water quality until the base saturation is close to 100 percent. The dissolution rate of the calcitic minerals is governed by the particle size of the limestone used. Particles with a diameter over 0.3 mm will be used to a very small extent. As nearly all the runoff percolates through the soil column, a high base saturation is needed to get a stable and long lasting effect on the runoff water. The amounts needed to get a satisfying base saturation are estimated to be 35 to 50 ton/ha. This implies that soil liming is one order of magnitude more costly than standard lake liming techniques for surface water. Although vast efforts may soon be needed in soil and forestry management in Scandinavia, the costs involved in soil liming emphasize the importance of defining the goal of every liming project. |
| AN HISTORICAL OVERVIEW OF A SUCCESSFUL LAKES RESTORATION PROJECT IN BATON ROUGE, LOUISIANA | Ronald M. Knaus; Ronald F. Malone | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 412 - 415 | AN HISTORICAL OVERVIEW OF A SUCCESSFUL LAKES RESTORATION PROJECT IN BATON ROUGE, LOUISIANA | The City Park Lake and the University Lakes complex have long been a source of pride to the citizens of Baton Rouge. This five-lake system comprises 300 acres. Over the past 50 years all aspects of the lakes have deteriorated with massive fishkills occurring on a regular basis during the warm summer months. In 1977 the City-Parish Government of East Baton Rouge asked the Institute for Environmental Studies at Louisiana State University to draft an Environmental Impact Statement and a Section 314 grant application to the Environmental Protection Agency to correct the hypereutrophic conditions in the five lakes. Then followed 2 years of negotiations gaining public support for the dredging project and obtaining areas for dredge spoil deposition. In September 1980 the project went out for bidding to the contractors, but because of the distance the spoil had to be pumped, bids far exceeded the $3 million available for the project. After several new dredging plans were presented, a large majority of people affected by the dredging gave approval to a plan using 30 percent in-lake disposal, and 70 percent off-site disposal at a very close location. In June 1981, the low bid for $2.09 million was accepted. Dredging commenced in November 1981. After the removal of 490,000 m3of lake bottom material, dredging ended in May 1983. In the post-dredging monitoring program, a group of 15 interested citizens was designated by the mayor to serve on the University Lakes Commission to oversee the monitoring of the lake waters, stabilization of shorelines and spoil banks, and to recommend funding for recreational use of the lakes and the immediately adjacent land areas. |
| THE TROPHIC STATE CONCEPT: A LAKE MANAGEMENT PERSPECTIVE | Robert E. Carlson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 427 - 430 | THE TROPHIC STATE CONCEPT: A LAKE MANAGEMENT PERSPECTIVE | Trophic state is fast becoming a nonconcept because of the confusion over its proper definition. The lack of agreement to trophic definition stems from its early typological origins, the fusion of causal factors with the resulting biological condition, and the assumption of the complex nature of the concept. A medical analogy of obesity is used to illustrate that trophic state can easily and unambiguously be determined by the measurement of plant biomass alone. |
| RESERVOIR MANAGEMENT PLANNING: AN ALTERNATIVE TO REMEDIAL ACTION | Donald W. Anderson | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 423 - 426 | RESERVOIR MANAGEMENT PLANNING: AN ALTERNATIVE TO REMEDIAL ACTION | Tellico Dam and Reservoir were constructed by the Tennessee Valley Authority (TVA) as a multipurpose water resources project on the Little Tennessee River in eastern Tennessee. Purposes of this project include industrial and residential shoreline development, recreation, water supply, navigation, flood control, and power generation. To achieve these objectives without sacrificing the high water quality in Tellico Reservoir, TVA has undertaken a water quality management program to guide reservoir development. The resulting reservoir water quality management plan will recommend maximum allowable waste loads, industrial siting requirements, water use classifications and criteria, and fisheries management. This in conjunction with a reservoir land use plan, will provide comprehensive development guidelines for Tellico Reservoir. Implementation of the plan is to be accomplished through a unique blend of regulatory and nonregulatory measures carried out by TVA and the State of Tennessee. To facilitate incorporation of its recommendations into the water quality regulatory program, the reservoir water quality management plan will be formally adopted as a portion of the State Water Quality Management Plan. Through its authority as manager of reservoir lands, TVA will implement nonpoint source control recommendations for which the State lacks regulatory authority. This integration of environmental planning into Tellico Reservoir development will provide for intensive uses of the reservoir's land and water resources while maintaining high levels of water quality. |
| DREDGING OF CREVE COEUR LAKE, MISSOURI | Greg Knauer | Lake and Reservoir Management | 1040-2381 | 0743-8141 | 1 | 1 | 1984 | 416 - 422 | DREDGING OF CREVE COEUR LAKE, MISSOURI | Creve Coeur Lake, an oxbow lake located in the Missouri Bottoms area of St. Louis County, Mo., is decreasing in surface area by deltaic deposition. In the early 1900's, the main lake had a surface area of approximately 81 ha (400 acres) and a small upstream lake. The main lake was reduced to an area of 32.4 ha (180 acres) by 1974 and the small lake completely filled. The average water depth decreased from 3.85 m (10 feet) to less than .77 m (2 feet). A 1971 engineering report included soils information, hydrologic and hydraulic investigations, field surveys, laboratory analyses, alternate designs with estimated costs, and economic analyses of benefits. Water quality problems noted in the 1971 water quality sampling program indicated high pH (>9.0), excessive nutrients, influx of fecal conforms and excessive algal growth (>10,000/ml). The result of the analyses indicated an optimum lake with an area of 133.4 ha (330 acres) dredged to a depth of 3.85 m (10 feet). St. Louis County initiated dredging in June 1974, completing it in December 1981. Baseline data collected in 1978 indicated high concentration of solids, excessive nutrients, and high levels of some heavy metals, including mercury. Sediment samples contained excessive nutrients with total phosphorus ranging from 1,200 to 2,200 μg/g and exceeded Missouri State Water Quality Standards for cyanide, mercury, phenols, iron, lead, nickel, and zinc. Routine water quality monitoring was performed monthly at the inflow, outflow, and five sampling stations in the lake. Sampling occurred during March-December 1981, while dredging was in operation, and during March-December 1982, after dredging was completed. Parameters routinely monitored included temperature, dissolved oxygen, Secchi transparency, pH, total phosphorus, ortho phosphorus, total nitrogen, fecal coliform, mercury, phenol, cyanide, and zinc. Fish flesh analyses were conducted on three species each quarter to monitor a bioaccumulation of mercury in the food chain. Analysis of the parameters during the dredging operations and the year following completion. of dredging did not indicate any significant differences attributable to the dredging operations. |
