Wednesday, November 13
10:30 am – 12:00 pm

Agenda subject to change.
Updated 7 November 2019

★ Denotes that the lead author is a student.

 

E1: Source Water Protection II

Moderator: Liz Royer
Vermont Rural Water Association, Essex Junction, Vermont

10:35 Holistic Response to Water Quality Changes Due to Lake Recovery in Drinking Water Reservoirs
Josh Weiss1, Jim DeWolfe2, Bill Becker2, Wendy Krkosek3, Graham Gagnon4, and Maureen Hodgins5
1Hazen and Sawyer, Baltimore, Maryland; 2Hazen and Sawyer, Denver, Colorado; 3Halifax Water, Halifax, Nova Scotia, Canada; 4Dalhousie University, Halifax, Nova Scotia, Canada; 5Water Research Foundation, Denver, Colorado

Many drinking water utilities in northeastern North America and parts of Europe face a unique set of conditions in which successful efforts to reduce atmospheric pollution have led to the phenomenon of lake recovery, leading to increases in pH, natural organic matter, and cyanobacterial blooms in surface water supplies. These long-term changes are problematic for treatment plants that were designed under fundamentally different water quality conditions. Halifax Water, in Nova Scotia, Canada, is currently experiencing such impacts, with steady increases in color, dissolved organic carbon (DOC), and taste and odor events in Lake Major and Pockwock Lake since the early 2000s, leading to an increase in chemical use at the treatment plants, reduced filter run times, and increased production of residuals. At the JD Kline Water Supply Plant, which employs a direct filtration process, operating conditions are now outside of the typical effective range for direct filtration.

In this presentation, we describe an ongoing applied research project to develop a data-driven decision support framework to help Halifax Water and other drinking water utilities better understand the impacts of long-term changes in water quality due to lake recovery, climate change, and other drivers to support capital planning and operational decisions. Critical questions that the DSF will help address include: how long will current trends continue; and what near-term and long-term investments are required to maintain an efficient, cost-effective, and reliable water supply?

10:55 Tackling Taste and Odor Issues: CCWA’s Approach to Proactively Manage Phosphorus and Improve Water Quality in an Integrated Water and Wastewater Treatment System
Roger Scharf and David Austin

Jacobs Engineering, Minneapolis, Minnesota

The Clayton County Water Authority (CCWA) is aggressively evaluating and implementing solutions to predict and prevent taste and odor in its source water reservoirs. Focused on both the cause and effect of algae blooms, the comprehensive approach includes a variety of management measures to identify, predict, control, and mitigate taste and odor. Data to identify potential taste and odor events includes permanent reservoir monitoring probes, daily sniff and taste tests throughout the distribution system, and a rigorous field sampling program for water quality, algae, and taste and odor compounds. CCWA is developing a predictive model which will utilize this data to identify the potential for algae blooms and optimize process control of new source water treatment systems. These treatment systems include recently installed reservoir oxygenation systems in two reservoirs, an aeration system in one reservoir, and back-up measures at water treatment plants. Upstream of the reservoirs, CCWA is assessing phosphorus reduction in the constructed wetlands and wastewater plant that are connected to their source water reservoirs. Through piloting a novel phosphorus scavenging approach in the constructed wetlands and evaluating phosphorus removal options at a wastewater plant, CCWA will determine the best comprehensive approach to meet the target phosphorus levels for both permit compliance and source water quality control.

11:15 Leveraging Source Water Protection Funds for Large-Scale Projects
Bradley Hufhines and James McCarty

Beaver Water District, Lowell, Arkansas

Beaver Water District (BWD) formally adopted its first source water protection (SWP) plan over 12 years ago which was completed in tandem with the Beaver Lake Watershed Protection Strategy (BLWPS) for BWD and partners. Together, these documents guide our SWP activities within the watershed. A sustainable source of funding was adopted by the BWD Board of Directors in 2016 to support the SWP plan and BLWPS, dedicating $0.04 per every 1000 gallons sold to a specific SWP fund. Best management practices (BMP) can be expensive to implement and having funding set aside allows BWD to act quickly when the need arises. Dedicated SWP funding allows BWD to provide match for partner organizations that are implementing BMPs that help obtain goals and targets within our SWP Plan and BLWPS. BWD is currently involved in a Natural Resource Conservation Service (NRCS) Regional Conservation Partnership Program (RCPP) initiative to improve agricultural practices and restore stream reaches on the West Fork of the White River, a high-priority sub-watershed with critical water quality and streambank erosion issues. This 5-year project scheduled to be completed in 2022 has many collaborating partners, including State and county agencies, municipalities, and non-profit organizations. RCPP represents our best use to-date of match funding from our SWP fund to leverage large collaborative projects. The $8 million-dollar effort includes cash and in-kind match from BWD totaling $1.2 million-dollars yielding an almost 7:1 return on our investment. The RCPP program will result in a reduction of sediment and nutrient transport to Beaver Lake.

11:35 Reservoir Sediment Studies to Support Increasing Drinking Water Storage in a Flood Control Reservoir, Littleton Colorado
Craig Wolf and Nathan Jahns

GEI Consultants, Inc., Denver, Colorado

The US Army Corps of Engineers and regional water providers are increasing water storage in Chatfield Reservoir, to help meet the growing demand for water in the Denver metropolitan area. The project’s Adaptive Management Plan identified water quality as a key concern given the expansion of the hypolimnion and inundation of shoreline areas with the increased pool elevation. Expansion of the hypolimnion will increase the areal coverage of anoxic sediments which could increase internal phosphorus loading and impinge on the TMDL. Furthermore, construction and dredging activities could increase the release of reduced contaminants from anaerobic sediments and increase mercury methylation in the sediment. A key driver regarding the uncertainties of impacts from the sediments, was the post runoff conditions from the Hayman Fire burn scar which resulted in exceedances of the mercury water quality standard when watershed sediments were deposited in the reservoir.

A multi-faceted sampling plan was developed to evaluate metals concentrations in sediment, water, and fish tissues. In addition, sediment elutriate tests were performed to evaluate the risk of disturbed sediments causing potential exceedances of water quality standards, while phosphorus fractionation, anoxic nutrient release rates, and oxygen demand studies were performed on reservoir sediments. A substantial internal nutrient loading event in 2018, initiated the phosphorus fractionation and anoxic release study, a follow-up to the 2014 baseline study. The metals data supported a successful dredging project without water quality violations, while the sediment nutrient studies will validate the reservoir model used to characterize nutrient-algae dynamics given future reservoir operations.

 

E2: Salt III – Salinization of Surface Waters

Moderator: Robin Valleau
Queen’s University, Dorset, Ontario, Canada

10:35 Salinization and Alkalinization of a Large Mid-South Hydroelectric Reservoir (Kentucky Lake, USA) as a Result of Human Activity
Susan Hendricks1, David White1, Bommanna Loganathan2, Kate He3, and Kathleen Condon3
1Hancock Biological Station, Murray, Kentucky; 2Department of Chemistry, Murray State University, Murray, Kentucky; 3Department of Biological Sciences, Murray State University, Murray, Kentucky

Increased salinization and alkalinization of lakes and reservoirs over the past several decades are well documented for the World’s northern regions and are related largely to human activity, particularly the ever-increasing use of road salts. The water quality of Kentucky Lake, the terminal hydroelectric impoundment on the Tennessee River system, has been monitored for a number of water quality parameters since 1988. Trend analyses of variables associated with salinity and total alkalinity indicate that calcium, chloride, and alkalinity have increased significantly over the past 3 decades: Calcium ion concentrations have doubled in some areas of the lake from < 12 mg/L in 1988 to over 30 mg/L in 2018. Chloride has increased from 5 mg/L to 10 mg/L, and alkalinity has increased from 50 mg/L to 60 mg/L since 1988. The largest source of new calcium and chloride ions is likely road-salt runoff. The Tennessee River basin is very large (100,000 km2) and determining sources of calcium and chloride remain difficult, but there are some trends. The six counties surrounding Kentucky Lake alone have experienced a 100% increased use of de-icing brine since 2002. Liming of regional agricultural soils also has increased significantly. Although regional wet deposition of calcium has been low (~ 2.0 kg/ha) since 2000, it has more recently increased to 3.5 kg/ha. The long-term effects of increased salinization and alkalinization on lake productivity and the development of favorable conditions for invasive species such as zebra mussels have only recently emerging; continued monitoring will address effects on aquatic biota.

10:55 How Much Is Too Much? Lethal Chloride Concentrations Determined for Daphniids in Soft Water Can Help Support Watershed and Lake Management Actions
Martha P. Celis-Salgado1, Shelley E. Arnott 1, Robin Valleau 1, Andrew M. Paterson 1,2, and John P. Smol1
1Queen’s University, Department of Biology, Kingston, Ontario, Canada; 2Dorset Environmental Science Centre, Ontario Ministry of the Environment, Conservation and Parks, Dorset, Ontario, Canada

Chloride concentrations have been increasing in many lakes in Ontario, Canada, due to the application of road salt for winter maintenance. Daphniids are affected by water contaminants depending on the hardness of water, becoming more sensitive to many toxics in soft water. Based on our paleolimnological research suggesting significant effects of chloride on the community composition of zooplankton in soft water lakes, we used reagent quality NaCl to conduct 21 d static with 48 h renewal bioassays with 10 isofemale lines of Daphnia pulicaria, and 5 other species of Daphnia that commonly occur in the Boreal Shield lakes. Organisms were collected from soft water lakes in central Ontario, fed 1 mg carbon/L/day, and the bioassays were conducted with < 24 h old neonates at 20 °C and 16:8 h light:darkness in a soft water medium (FLAMES). The daphniids were examined daily for survival and reproduction. LC50s were calculated for each clonal line and species under 7 chloride treatments, ranging from 0.39 to 150 mg/L in the FLAMES medium. We found that the soft water clonal lines and species tested are more sensitive to chloride in soft water lakes compared with findings for daphniid species in hard water. Our results indicate that D. catawba, D. mendotae and D. minnehaha are especially sensitive to road salt in soft water lakes, and reproduction is affected in all species above 45 mg L-1 of chloride. The tolerance levels found for the various species studied provide information to revise the management practices of the application of road salts.

11:15 Extended Discussion

 

E3: Phosphorus Inactivation III – Aluminum

Moderator: Ken Wagner
Water Resource Services, Wilbraham, Massachusetts

10:35 Assessing the Fate of Alum 12 Years After Application in Lake McCarrons (Roseville, Minnesota)
Bob Fossum, Britta Belden, Mark Houle

Capitol Region Watershed District, Saint Paul, Minnesota

Lake McCarrons in Roseville, Minnesota is a 75-acre mesotrophic lake that supports a variety of recreational opportunities. The lake is located in the Capitol Region Watershed District (CRWD). In 2004, CRWD treated the lake with alum to decrease internal phosphorus loading, improve water quality, and meet the State deep lake total phosphorus (TP) standard (40 mg/L). The alum was uniformly applied across the entire lake surface. Since the treatment, the lake has met State standards annually, but hypolimnetic TP concentrations have been gradually approaching pretreatment levels, prompting an evaluation to assess the alum treatment efficacy after 14 years.

To evaluate the efficacy of the 2004 alum treatment, 23 sediment cores were taken in a grid across the whole lake in 2017 and were examined for: 1) the presence and thickness of the alum layer, and 2) the thickness and composition of sediment overlying the alum layer (if present).

Results from the cores revealed that alum was present in only 10 of the 23 cores. Additionally, the alum was not distributed equally, and where it was present, the alum layer was overlain by sediment. The thickest layers of alum corresponded to the deepest parts of the lake, with alum thickness decreasing with depth. Conversely, the thickest layers of overlying sediment coincided with the thinnest layers of alum, potentially preventing the alum from interacting with hypolimnetic phosphorus. This evaluation also explores potential factors that may have influenced the distribution of alum and sedimentation rates. Results will inform future management of Lake McCarrons.

10:55 The East Pond (Maine) Alum Treatment Part 1: Establishing an Alum Dose
Whitney King1, Danielle Wain2, Charlie Baeder2, and Ken Wagner3
1Colby College, Waterville, Maine; 27 Lakes Alliance, Belgrade, Maine; 3Water Resource Services, Wilbraham, Massachusetts

The largest alum treatment to date in New England was conducted on East Pond (Smithfield, Maine) in two phases in June and October 2018. East Pond had experienced serious blue-green algae blooms for over two decades due to historic anthropogenic inputs of phosphate with excess phosphate accumulating in the lake sediments. Annual blooms occurred when episodically anoxic bottom water released iron-bound phosphate from the sediments to the water column. Increased algal biomass reinforced water column stratification amplifying the internal nutrient load. Sequential chemical extractions of sediment samples were used to define the iron, aluminum, and phosphate sediment geochemistry under oxic and anoxic conditions. At a 3:1 molar ratio of Al:Fe the sediments (alum addition of 45 g Al/m2 sediment) retained phosphate. This ratio is similar to other Maine lakes that do not exhibit reductive dissolution of sediment bound phosphate, suggesting that the alum dose should consider both iron and phosphate sediment geochemistry.

11:15 The East Pond (Maine) Alum Treatment Part 2: Monitoring and Evaluation
Danielle Wain1, Whitney King2, Charlie Baeder1, and Ken Wagner3
17 Lakes Alliance, Belgrade Lakes, Maine; 2Colby College, Waterville, Maine; 3Water Resource Services, Wilbraham, Massachusetts

The largest alum treatment to date in New England was conducted on East Pond (Smithfield, Maine) in two phases in June and October 2018. In Part 1 of this presentation, planning, dosing, and execution were discussed. In total, 260 ha of lake sediment were treated with 360,000 kg of Al(OH)3 with a total cost of $1.1M. Throughout the treatment, pH , alkalinity, and dissolved aluminum was monitored by 7 Lakes Alliance/Colby College to ensure the treatment did not significantly lake chemistry and ecology. In summer 2018, after the first phase of treatment, East Pond had excellent water clarity (Secchi depth ~ 5 m) and consequently the lake did not stratify at all, despite hot weather with low winds in August. With no internal load, phosphorus was below 10 ppb through the summer, resulting in a significant reduction in cyanobacteria and no bloom in August, when the water quality used to be the worst. As a result of the reduction of algal biomass over the summer, monitoring through winter under the ice and during spring turnover shows continued high oxygen all the way to the sediments. While early indicators suggest that the alum treatment was effective, in summer 2019, we will install a thermistor chain to better monitor any stratification events that may occur, in addition to continuing with weekly monitoring of Secchi, oxygen, phosphorus, and algae to understand the evolution of the ecological system in the second year.

11:35 Incorporating Internal Nutrient Loading Into TMDL Recommendations at Lake Wister, Oklahoma
Steve Patterson1 and J. Thad Scott2
1Bio x Design, Poteau, Oklahoma; 2Baylor University, Waco, Texas

In August 2014 and July 2016 the Poteau Valley Improvement Authority applied approximately 16,000 pounds of liquid alum (aluminum sulfate) and 8,000 pounds of liquid sodium aluminate to 100 surface acres of Quarry Island Cove in Lake Wister, a 6,300-acre flood control, recreation, and water supply reservoir in LeFlore County, eastern Oklahoma. This pilot project was undertaken for multiple purposes: to reduce the concentration of mobile phosphorus levels in cove sediments, to attempt reduce the concentrations of disinfection byproducts (DBPs) in treated water, and to explore the potential of a whole-reservoir alum application. The application was intended to reduce the concentration of cyanobacteria in Quarry Island Cove at the time of year when those concentrations are at their highest. Other attempts to flocculate and settle cyanobacteria blooms using clays and various other materials have shown variable results, apparently effective in some cases and ineffective in others. This was the first large scale alum application in Oklahoma and the first in a US Army Corps of Engineers managed reservoir. The application was made safely and successfully, without adverse impacts to fish or significant alteration of pH or alkalinity. Cyanobacteria cell counts were reduced 80% in 2014 and 24% in 2016. Sediment cores taken before and after application showed a 70–90% reduction in phosphorus release under anoxic conditions and a 50% reduction in potential mobile phosphorus in the top 10 cm of sediments.

 

E4: Paleolimnology II – Eutrophication

Moderator: Andrew Paterson
Queen’s University, Dorset, Ontario, Canada

10:35 Using Paleolimnology to Assess Whether Nutrient Enrichment From Nova Scotia Mink Farms Are Affecting Eutrophication Patterns of Local Lakes
Nell Libera1, Joshua Kurek2, and John P Smol1
1Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen’s University, Kingston, Ontario; 2Department of Environmental Science, Mount Allison University, Sackville, New Brunswick

Cyanobacterial blooms in southwest Nova Scotian lakes have prompted concerns from local residents and environmental organizations that these blooms may be linked to the large number of mink fur farms in the area. The high volumes of phosphorus-rich wastes produced by this industry have remained largely unregulated until 2013. Despite a 400% increase in pelt production since the late-1980s, structured water chemistry sampling regimes for regional freshwaters were not initiated until 2008. These initiatives produced 10 years of monitoring data indicating hypereutrophic conditions in headwater lakes with fur farms in their catchment (e.g., total phosphorus values surpassing ~0.5 mg/L), as well as eutrophic conditions in downstream sites. Here, we use paleolimnological data to analyze strategically selected lakes to examine long-term trends in eutrophication-related proxy data. This extends the monitoring window back in time to pre-date the establishment of the mink farms. Changes in sedimentary diatoms, chrysophytes and spectrally-inferred chlorophyll a are used to compare the trophic histories of sites with and without mink farms in their catchments. Our preliminary results show differences in the environmental trajectories of reference lakes and lakes impacted by mink farms over the past ~150 years. Counter to our reference lakes, diatom records from mink farm impacted lakes show marked compositional changes over the past few decades that reflect eutrophication trends, providing evidence that fur farming has potentially impacted water quality. This study highlights which sites are most vulnerable to fur farming practices and provides important insights for the management of these watersheds.

10:55 Using Subfossil Midges to Assess the Impacts of Mink Farming on Hypolimnetic Oxygen in Lakes From Southwestern Nova Scotia
Julia Campbell1, Joshua Kurek1, Nell Libera2, and Abbie Gail Jones1
1Environmental Change and Aquatic Biomonitoring Lab (ECAB), Mount Allison University, Sackville, New Brunswick, Canada; 2Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, Ontario, Canada

The mink fur farming industry of Nova Scotia has been one of the top agricultural exports of the province. This industry prompted recent debate on water quality declines in nearby headwater lakes, such as Nowlans Lake, which has experienced reoccurring algal blooms and very high measures of nutrients (e.g., total phosphorus > 600 μg/L in 2017). Sedimentary remains of chironomids and chaoborids from several impact (Nowlans) and reference lakes were used as bioindicators of long-term environmental change due to their sensitivity to dissolved oxygen concentrations [DO]. Invertebrate remains were recovered from lake sediment cores spanning the ~1900s to present. Visible reflectance spectroscopy (VRS) chl-a was also measured from sediments as a proxy of whole-lake primary production. Preliminary results at Nowlans Lake indicate fewer chironomid taxa associated with higher [DO] (e.g., Stempellina) from the ~1950s to present and more taxa associated with lower [DO] (e.g., Endochironomus) from the ~1990s to present. More remains of chaoborids relative to chironomids from the ~1990s to present also suggest decreases in [DO]. These trends are concomitant with greater VRS chl-a and coincide with the growth of the mink industry. This research determines pre-disturbance conditions and provides long-term data necessary to understand the contributions of mink farms to regional water quality declines. Determining the drivers of eutrophication and impacts to lake ecosystems will aid in land-use management and recovery strategies for these headwater aquatic systems.

11:15 A Paleolimnological Study Suggesting That Climate Change Can Be a More Important Driver of Lake Ecosystems Than Cultural Eutrophication
Marie-Pierre Varin1, Paul B. Hamilton2, and Frances R. Pick1
1University of Ottawa, Ottawa, Ontario, Canada; 2Canadian Museum of Nature, Ottawa, Ontario, Canada

Nutrient loading from various point and non-point sources is considered the most important anthropogenic stressor negatively impacting surface waters around the world. Heney Lake in southwester Quebec experienced cultural eutrophication in the mid-90s from nutrient loading originating from a commercial aquaculture facility. A class-action lawsuit brought forward by the lake association led to a monetary settlement for a major restoration project. Iron chloride (217 tons) was added to this iron-deficient lake in fall 2007 to precipitate phosphate concentrations and reduce in lake total phosphorus (TP) and algal biomass. Since that time, a slow rise in water column TP has led the lake association to consider another iron addition to the lake. We conducted a paleolimnological study in order to determine the pre-European settlement conditions of Heney Lake to help guide the association to set a realistic target condition. This required the development of a diatom based transfer function for phosphorus, based on an analysis of lake water chemistry and diatom assemblages from 31 lakes across the Heney Lake region (Outaouais). While ultimately it was not possible to provide a statistically significant and accurate prediction of past TP conditions, it was possible to derive a model to predict the past Fe concentrations. However, the most interesting outcome of this analysis of the history of Heney Lake was the finding that the shift towards more eutrophic diatom species during cultural eutrophication represented a very minor signal compared to that associated with climate change over a longer time frame.

11:35 Paleolimnological Assessment of Six Lakes on the Kissimmee Chain, With Implications for Restoration of the Kissimmee-Okeechobee-Everglades System, Florida USA
Thomas J. Whitmore1, Melanie A. Riedinger-Whitmore1, Francesca M. Lauterman1, Neil Rose2, Handong Yang2, Jason H. Curtis3, Christine Leonard1, Zachary Leyton Rivera-Reed1, Karla Alvarado1, Deveny E. Evans1, Austyn Scott1, and Daniel Franklin1
1Department of Biological Sciences, University of South Florida St. Petersburg, St. Petersburg, Florida; 2Environmental Change Research Centre, University College London, London, United Kingdom; 3Department of Geological Sciences, University of Florida, Gainesville, Florida

This study presents a paleolimnological assessment of historical changes in six lakes of the Kissimmee Chain of Lakes. These lakes are headwaters of Lake Okeechobee and the Everglades and are part of the Comprehensive Everglades Restoration Plan. Substantial changes in water quality during the 20th century arose from urban and agricultural influences. Alteration of associated wetlands occurred during channelization of the Kissimmee River. We present 18 sediment cores that document pre-disturbance conditions (early to mid-19th century) in Lakes Tohopekaliga, East Tohopekaliga, Kissimmee, Cypress, Jackson, and Marian. Past limnetic nutrient and chlorophyll a levels, and limnetic pH, were estimated with diatom-based transfer functions. Stable carbon and nitrogen isotopes document changes in primary productivity and nitrogen sources. Sedimented algal and cyanobacterial pigments provide evidence about past changes in primary productivity. Pollen in sediments was used to assess former associated wetland influences, and macrofossils documented changes in aquatic-plant communities. These lakes were originally alkaline and meso-eutrophic (~30–40 µg/L total P, ~ 20–30 µg/L Chl-a), with little evidence of dystrophy. Cyanobacteria were present intermittently throughout their histories, but increased significantly after the mid-20th century, leading to diverse ecological changes. Chara was displaced by submerged taxa then floating-leaved nymphaeids as water clarity declined. Pollen revealed evidence of swamps formerly associated with Lakes Kissimmee and Marian, but dry prairies and grasslands were associated with early histories of Lakes Jackson, Cypress, and East Tohopekaliga. Effective restoration plans must consider that these lakes were moderately high in productivity, contrary to some previous assumptions about oligotrophy.

 

E5: Aquatic Invasive Species III – Survey and Mapping

Moderator: Amy Smagula
New Hampshire Department of Environmental Services, Concord, New Hampshire

10:35 Champlain Canal Barrier Feasibility Study for Aquatic Invasive Species
Meg Modley

Lake Champlain Basin Program, Grand Isle, Vermont

LCBP/NEIWPCC, NYS Canal Corporation, NYSDEC, USFWS, LC Sea Grant, and others have been working together for over a decade to address the threat of aquatic invasive species spread by means of the Champlain Canal.  USACE and LCBP/NEIWPCC have executed a contract to conduct the feasibility study authorized in the Water Resources Development Act.  Learn more about the long-term partnership effort to address the Champlain Canal as a leading vector of AIS spread between the Champlain, Hudson, and Great Lakes systems and the different measures and alternatives being evaluated.

10:55 Drone Mapping of Water Chestnuts
Jarlath O’Neil-Dunne1, Kimberley Jensen2, and Emma Estabrook1 (Madeline Hayes presenting)
1University of Vermont, Burlington, Vermont; 2Vermont Department of Environmental Conservation, Montpelier, Vermont

Water chestnut is an invasive species that is actively managed within the Lake Champlain Basin. For the past two years the Vermont Department of Environmental Conservation (DEC) and the University of Vermont have partnered on an innovative program using drone technology to map, monitor, and measure this invasive species. Drone technology enabled DEC to more effectively target its removal efforts and quantify results. This presentation will dive into the capabilities and limitations of using of drones for aquatic invasive species that will be of value to any organization considering implementing this technology.

11:15 Invasive Species Detection in Northeast Regional Lakes using Environmental DNA (eDNA)
Alison Watts1 and Denise Blanchette2
1University of New Hampshire, Durham, New Hampshire; 2Maine Department of Environmental Protection, Augusta, Maine

This project will develop and conduct an eDNA sampling program for target invasive species in northeastern lakes during the summer of 2019. The project will provide proof of concept, and initial eDNA data for two invasive invertebrates; Asian clam (Corbicula fluminea) and zebra mussel (Dreissena polymorpha). Both of these species are present in some areas of the region and are considered at risk of invading currently uninfected lakes. Improved early detection methods will support timely response and management actions. Samples will be collected in Lake Bomoseen, Vermont and Lake George, New York, which have known infestations of both species, and from an uninfected control lake. Samples will be analyzed using both metabarcoding and digital droplet PCR. We will compare the two methods and discuss recommendations for incorporation of eDNA analysis into invasive species monitoring in New England lakes.

11:35 Starry Stonewort – Two Decades in Michigan
G. Douglas Pullman

Applied Biochemists, Alpharetta, Georgia

Goal directed lake management programs are challenged when lake ecosystems are disturbed by invasive and opportunistic species that compromise biological diversity, habitat complexity, and ecosystem stability. Starry stonewort can represent very significant challenge, but not an insurmountable hurdle to northern lake managers. Understanding can be a key component for successfully dealing with this threat to our lakes. The most predictable characteristic of starry stonewort (Nitellopsis obsusa) is that it is incredibly unpredictable. As an opportunistic invasive species, it is known to bloom and crash, but it is difficult to predict when this might happen. This unpredictability seems to be related to the reasons that this nuisance alga can “suddenly” become so weedy and why it can be so difficult to treat. It is critical to understand how a non-vascular plant can grow 8 ft tall or more, why do starry stonewort meadows boom and crash and when they do crash, what the impact will be to other aquatic plant species. Nuanced control is possible, and programs may be directed by unexpected expectations.

 

E6: Lake Restoration IV

Moderator: Erich Marzolf
St. Johns River Water Management District, Palatka, Florida

10:35 Assessment of Phosphorus Loads From Tile Drainage in the Jewett Brook Watershed of St. Albans Bay
Dave Braun and Don Meals

Stone Environmental, Inc., Montpelier, Vermont

Subsurface tile drainage is an essential water management practice on many agricultural fields, enabling crop production in fields otherwise too wet to farm. Once considered negligible, phosphorus (P) levels in tile drain discharge in many US regions are now recognized as potentially significant at field and watershed scales. Across the Lake Champlain Basin, the impacts of tile drainage on water quality have not been adequately assessed. We monitored 12 tile drains on silage corn and hay land on commercial dairy farms in the Jewett Brook watershed, St. Albans, Vermont for a full year. Tile drainage flow rates were measured continuously, and flow-paced composite samples were analyzed for total and dissolved P. Phosphorus concentrations varied across sites and seasons. Annual mean total P concentrations ranged from 45 to 1,166 µg/L across the 12 sites (median 185 µg/L). Lowest P concentrations tended to occur in December and highest concentrations in October. P loading rates among the 12 drains ranged from 0.12–1.12 kg/ha/yr and averaged 0.56 kg/ha/yr. The mean dissolved P loading rate was 0.27 kg/ha/yr, approximately 50% of the total P loading rate. Both total and dissolved P loading rates were significantly higher from row cropland compared to hayland. During the monitored year, approximately 26% of the total P load exported by Jewett Brook was contributed by tile drains. These results demonstrate that tile drains have the potential to contribute substantial quantities of P to surface waters in the Lake Champlain Basin.

10:55 Development and Validation of a Regional Lake Water Quality Vulnerability Screening Tool
Lindsay Johnston, Audrey Hiscock, Baillie Holmes, Jenny Hayward, Richard Scott, and Rob Jamieson

Centre for Water Resources Studies, Dalhousie University, Halifax, Nova Scotia, Canada

The occurrence of cyanobacteria blooms in several lakes in Nova Scotia in recent years has generated significant public awareness and concern. These events have generated questions related to which lake morphometric and watershed characteristics put lakes in the region at higher risk for eutrophication. A new study was initiated to develop and validate a regional lake vulnerability screening tool. The proposed screening tool consists of three tiers of increasing complexity. The first tier involves a high-level GIS-based risk assessment of the contributing watershed to estimate P loading, using publicly available spatial datasets (e.g., bedrock geology, land use, etc.). Lakes flagged as medium or high risk are evaluated under the second tier, which consists of a simple monitoring-based risk assessment (including nutrient characterization, bathymetric mapping, and water transparency). The final tier involves a detailed monitoring-based risk assessment to characterize thermal regime and estimate potential for internal loading. The risk assessment approach was then applied to lakes located within Cumberland County, located in northern Nova Scotia. Five lakes in the region were also monitored to produce data to validate the approach. The selected study lakes varied in size, depth and hydraulic characteristics, as well as degree and type of watershed development. The risk assessment framework will allow the province and municipalities to efficiently prioritize their resources for managing lakes within their jurisdiction.

11:15 Green Stormwater Infrastructure Research: Bioretention, Water Quality, and Nutrient Dynamics in Urban and Agricultural Settings
Stephanie Hurley, Joshua Faulkner, Michael Ament, Jillian Sarazen, Paliza Shrestha, and Eric Roy

University of Vermont, Burlington, Vermont

Green stormwater infrastructure (GSI) aims to manage runoff from impervious surfaces using natural processes to reduce hydrologic and water quality impacts on streams, rivers, and lakes associated with developed land uses. Bioretention systems, also called raingardens, are a type of GSI that utilizes soil media and vegetation to store and filter stormwater. While bioretention systems are proven to be successful at slowing and storing runoff and trapping sediments, bioretention systems have variable performance in capturing and filtering nutrient pollutants, specifically phosphorus and nitrogen. This presentation will review recent and ongoing research based on three different bioretention research studies conducted at the University of Vermont, across urban and agricultural land uses. Details of study designs and research results—including specific concerns the use of compost in bioretention soil media causing nutrient leaching, and the potential to capture phosphorus by using aluminum- and iron-based Drinking Water Treatment Residuals (DWTR) as a soil amendment—will be presented.

11:35 Extended Discussion