Wednesday, November 13
3:30 pm – 5:00 pm

Agenda subject to change.
Updated 1 November 2019

★ Denotes that the lead author is a student.


G1: Oxygenation I

Moderator: Craig Wolf
GEI Consultants, Inc., Denver, Colorado

3:35 A “Toolbox” Approach to Managing the Water Quality of a Southern California Reservoir
Seyoum Gebremariam, Pal McCormick, and Stephen Reynolds

Metropolitan Water District of Southern California, La Verne, California

The Metropolitan Water District of Southern California operates a storage reservoir that supplies nearly 500,000 acre-feet of raw water annually to drinking-water utilities in southern California. Water-quality concerns in this reservoir include: 1) blooms of various taste-and-odor (T&O) producing cyanobacteria, both planktonic and benthic; 2) release of dissolved manganese (Mn) and phosphorus (P) from anoxic sediments; and 3) more generally, high nutrient availability for cyanobacterial growth. These issues are addressed using operational flexibility (multi-tiered outlet tower, lake bypass capability) combined with active management, including an aeration system to destratify the lake, and applications of copper sulfate for cyanobacteria control. Seasonal aeration helps prevent anoxia and the dissolution of Mn and P from reservoir sediments, although nutrient balance computations indicate minor internal loading of P. Most nutrient loading is external and originates from outside the watershed. Artificial circulation does not suppress cyanobacterial growth in this nutrient-rich reservoir. Therefore, routine monitoring, including water sampling and SCUBA diving to collect benthic material, is required to proactively detect T&O production and identify the source(s) of this production (planktonic vs. benthic) and the organism(s) responsible. Outlet tower tier changes and partial or complete reservoir bypass can be used to temporarily avoid cyanobacteria issues. If problems persist, then the lake is treated with copper sulfate to target the source of the T&O production. These treatments are optimized to target the specific locations and organisms responsible for the production by adjusting the quantity and granule size of applied copper sulfate and the application map.

3:55 The Effects of Surface Mixer Operation in a Drinking Water Supply Reservoir
Emily Slavin1, Danielle J. Wain2, R.G. Perkins3, and C. Blenkinsopp1
1University of Bath, Bath, England, UK; 2Colby College Waterville, Maine and 7 Lakes Alliance, Maine; 3Cardiff University, Cardiff, Wales, UK

To reduce the problems associated with the effects of thermal stratification on drinking water quality, utilities are increasingly investing in surface mixing destratification systems. In England and Wales since 2013, 4 utilities have installed 11 surface mixers (SMs) in water supply reservoirs. However, the effects of surface mixers on water quality are not fully understood as this is a relatively novel method of artificial destratification. Here, we present the effects of a surface mixer in a shallow hypereutrophic reservoir in Somerset, UK, which has seen an increase in phytoplankton counts since the installation of a surface mixer. A week-long field survey was conducted in this reservoir with intensive water sampling and in-reservoir monitoring using multi-parameter probes and an Acoustic Doppler Velocimeter (ADV). During the field campaign the surface mixer was turned off for 33 hours and 30 minutes and back on again. Preliminary results indicate that surface mixer operation improved distribution of dissolved oxygen concentrations throughout the water column, and created a uniform temperature profile, but had considerable impact on the currents near the sediments. We hypothesise that in a shallow, hypereutrophic reservoir, surface mixer operation increases passive transport of phytoplankton through the water column between the sediments where resuspension causes release of bioavailable nutrients, and the surface where light is available for photosynthesis.

4:15 A Decade of Inversion Oxygenation: Analysis of Trends in Nutrient Reductions in Michigan Lakes
Jennifer L. Jermalowicz-Jones

Restorative Lake Sciences, Spring Lake, Michigan

Inversion oxygenation has been used on inland lakes in Michigan (USA) for over a decade to improve water quality. Water quality impairments such as excessive cyanobacteria blooms, reduced water clarity, and excess nutrients have resulted in accelerated eutrophication of many lakes which reduces property values and creates public health issues. Analysis of water quality data parameters described above relative to responses from inversion oxygenation have demonstrated that this technology effectively reduces key nutrients in lakes and consequently improves overall water quality through increased water clarity (mean increase of 2 meters over a five year period; p < 0.05) and reduced algal blooms (mean chlorophyll a reduced by a mean of > 2.0 µg/L over a five year period; p < 0.05).

The possible mechanisms of this technology on these parameters include nitrification of ammonia which is a dominant nutrient source for primary production and reductions in total phosphorus (≥ 50% reduction in mean concentrations over a five-year period; p < 0.05), though reductions in latter are less understood. Possible mechanisms for phosphorus reductions are discussed and warrant further research. Several case studies were used in the analysis and show promising evidence of nutrient reduction that result from inversion oxygenation. However, the influx of nutrients from an unmanaged catchment can negate many of the improvements made by this technology and thus mitigation of external nutrient loads is critical for successful nutrient reduction and associated water quality impairments. Reduction of cyanobacteria blooms is especially marked in lakes where runoff is controlled.

4:35 Preliminary Evaluation of Nannobubblers to Improve Water Quality and Reduce Cyanobacteria Blooms
Patrick Goodwin

Vertex Water Features, Pompano Beach, Florida

Nannobubbler seems to be the new buzz word in our industry, but what is a nanobubbler, and how does it work to improve water quality and reduce cyanobacteria blooms? How does it compare to other technologies in our industry and where is it best utilized? This presentation attempts to answer those questions by presenting the current peer-review literature regarding nanobubble technology and provides two case studies where nannobubblers were used to improve water quality and reduce cyanobacteria blooms.


G2: High Quality Lakes

Moderator: Perry Thomas
Kentucky Division of Water, Frankfort, Kentucky

3:35 A Ten-Year Retrospective of Minnesota’s Sentinel Lakes Long-Term Monitoring Program
Casey Schoenebeck1, Lee Engel2, Jesse Anderson3, Tim Martin4, and Will French4
1Minnesota Department of Natural Resources, Glenwood, Minnesota; 2Minnesota Pollution Control Agency, St. Paul, Minnesota; 3Minnesota Pollution Control Agency, Duluth, Minnesota; 4Minnesota Department of Natural Resources, St. Paul, Minnesota

In 2008 the Minnesota Department of Natural Resources and Minnesota Pollution Control Agency initiated a long-term program to monitor 25 representative lakes across Minnesota’s diverse ecoregions, stratified by depth and trophic state. Lakes in the Sentinel Lakes Program range from oligotrophic trout lakes in northern Minnesota’s boreal forest, to shallow hypereutrophic lakes in the agricultural southwest. Primary goals of the Sentinel Lakes Program are 1) to identify important biological, physical, and chemical trends in Minnesota lakes; 2) identify the mechanisms behind these trends; and 3) identify management solutions to ensure long-term sustainability of Minnesota’s lakes – given the presence of disturbances such as lakeshore development, climate change, and aquatic invasive species. This collaborative program has created a platform facilitating research to increase our understanding of stressor induced changes at the system level. In addition to water quality and fisheries trends, several case studies will also be presented – trends in cisco and cold-water habitat, trends in native zooplankton following an invasion of aquatic invasive species, hydrology and water quality dynamics between surface water and groundwater in shallow lakes, using paleolimnology results to guide restoration of an impaired prairie lake, and water quality and coldwater habitat models under future climate and land use scenarios. Future work includes advancing data visualization tools, tracking the dynamics of harmful algal blooms, quantifying the impacts of microplastics in water, sediment and fish, exploring the impact of invasive species on juvenile fish growth and recruitment, and expanding the network of temperature and oxygen sensors deployed year-round.

3:55 Saving the Best of What’s Left: Vermont’s Strategy for Turning Significantly Increasing Phosphorus Trends Around on Vermont’s Clearest Lakes
Kellie Merrell, Leslie Matthews, and Perry Thomas

Vermont Department of Environmental Conservation, Montpelier, Vermont

Vermont is currently stewarding some of the best lakes in the nation. Except for the Western Mountains Ecoregion, Vermont has a higher proportion of oligotrophic lakes than any other ecoregion or the nation. Stephens et al. 2015 found that Vermont had the fourth clearest lakes in the nation. The Vermont Watershed Management Division’s 2016–2018 Strategic Plan’s top goal is to “Protect Vermont’s pristine or “special waters by safeguarding these natural systems from deleterious change over the long term.” Forty-year trend data across 153 lakes, show phosphorus is increasing in Vermont’s oligotrophic lakes. Thanks in large part to the demand for improved water quality in Lake Champlain, Vermont has developed several innovative tools to reduce phosphorus pollution to surface waters, from both point and non-point sources. The Vermont Watershed Management Division is targeting those tools on a subset of the oligotrophic lakes with increasing phosphorus trends. The strategy being piloted identifies potential sources of phosphorus, appropriate tools, partners in each watershed, and potential funding sources. Outreach materials are then crafted for each lake and Vermont Watershed Management Division staff work collaboratively to implement the lake specific strategies. Unlike most of the rest of the nation, which must prioritize the restoration goal of the Clean Water Act, Vermont is in the unique situation that it needs to devise strategies to maintain the high quality of lakes under its stewardship not just because they are high quality lakes for Vermont, but because they are high quality lakes for the nation.

4:15 Revisiting Stratification: Effects of Climate Change in All Seasons
Lisa Doner

Plymouth State University, Plymouth, New Hampshire

High resolution, year-round temperature records from multiple, deep lakes in New Hampshire (Squam Lake, Danforth Pond and Newfound Lake) reveal surprisingly consistent stability in stratification that sets up within days of ice out and lasts until fall turnover encompasses all depths of the lake. This research reveals some apparent consequences of fewer snow cover days, later ice-cover, earlier ice-out dates and thinner ice cover, all typical of recent climate conditions, on lake stratification, minimum temperature and bottom oxygenation. The work also examines relationships between high flows in input streams in every season, and possible linkages of hydrologic events and deep-water hypoxia.

4:35 Integrated Critical Watershed Analysis: Prioritizing Lake Subwatersheds at Risk Using Co-Occurrence Analysis at Several Spatial Scales
Jeffrey A. Schloss1 and Dan Sundquist2
1University of New Hampshire Center for Freshwater Biology and Cooperative Extension and Cooperative Extension. Durham, New Hampshire; 2GreenFire GIS, Sutton, New Hampshire

We recently investigated a novel approach to prioritize and visualize critical sub-watersheds for Newfound Lake, a locally designated high-quality surface water, in New Hampshire. Previous GIS analyses on the Squam Lakes demonstrated that subwatershed and receiving basin characteristics along with co-occurrence analysis of water quality conditions and in-lake wildlife could allow for prioritizing subwatersheds for local protection as well as provide useful visualizations for local decision-makers and the public. For the Newfound watershed we used an intensive monitoring dataset collected by citizen lake and stream monitors. The approach was to use an empirically derived water and nutrient budget along with a GIS based analysis of subwatershed characteristics, at low, and medium spatial resolutions, to determine the subwatershed characteristics and metrics that had the greatest effects (positive and negative) on phosphorous loading and lake basin response. We then applied an integrated co-occurrence analysis at a higher spatial resolution to isolate the most critical sub-watershed areas to focus mitigation, protection and management activities. In addition, the results of our watershed assessment support the efforts of the watershed management outreach team in recommending variable minimum buffer widths and setbacks based on stream order as initially proposed by the Center for Watershed Protection. While the process sounds complicated, the resulting visualization products create a simplified and highly usable watershed management, planning and protection tool.


G3: Harmful Algal Blooms IV

Moderator: Todd Tietjen
Southern Nevada Water Authority, Las Vegas, Nevada

3:35 Cyanobacteria Bloom Assessment in Lakes of the Contiguous United States Using Satellite Observations
Sachidananda Mishra1,2, Richard P. Stumpf2, Andrew Meredith1,2, Blake Schaeffer3, Jeremy Werdell4, Bridget Seegars4, and Keith Loftin5
1Consolidated Safety Services, Inc., Fairfax, Virginia; 2National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science, Silver Spring, Maryland; 3US Environmental Protection Agency, Durham, North Carolina; 4National Aeronautics and Atmospheric Administration, Greenbelt, Maryland; 5US Geological Survey, Lawrence, Kansas

Cyanobacterial harmful algal blooms (CyanoHABs) are serious environmental, water quality, and public health issue worldwide. CyanoHABs produce toxins and odorous compounds that can adversely affect public drinking water supplies, as well as recreation, fisheries, and tourism. A method to systematically derive quantitative information on spatiotemporal distributions of CyanoHAB magnitude is needed, thereby allowing for effective evaluation of recreational and drinking water lakes. In this study, we present a method for estimating CyanoHAB magnitude in freshwater lakes using satellite observations. CyanoHAB magnitude was estimated as the spatiotemporal mean of satellite-derived areal CyanoHAB biomass, which is calculated from Medium Resolution Imaging Spectrometer (MERIS) and Ocean Land Color Imager (OLCI) sensors. CyanoHAB magnitudes in all satellite-resolvable Contiguous United States (CONUS) lakes were calculated for the entire MERIS (2003–2011) and OLCI (2016–present) time series. These CONUS lakes were further ranked based on median magnitude over the years. With 300 m × 300 m resolution, 2,369 lakes were evaluated, with the majority of these lakes in Minnesota, Maine, Michigan, Texas, and Florida. About 40% of all the lakes had CyanoHAB magnitude of potentially high risk (based on World Health Organization guidelines), compared with 1/3 of lakes in the National Lake Assessment having cyanotoxins. These lakes were found in all regions of the country. Ranking of lakes provides actionable insight, which can be used by water quality managers to prioritize management strategies. The same method could be transferred to other geographic regions and therefore be applied to lakes around the world for assessing CyanoHABs.

3:55 Monitoring Changes in Lake Eutrophication Using Unmanned Aerial Vehicles (UAVs)
James Killarney, Kathleen Dunckel, Kevin Spigel, and Janis Balda

Unity College, Unity, Maine

Early detection of harmful algal blooms (HABs) enables natural resource managers to prioritize remediation efforts to affected bodies of water. A major challenge to understanding this global issue is the extensive amount of field data that must be physically collected and analyzed. A possible solution to this is to develop methods for identifying water quality impoverishment using remote sensing. The use of unmanned aerial vehicles (UAVs) as environmental monitoring tools is expanding and is currently being used to study several chemical and biological systems. In this study, data is being collected using a multispectral imager (R, G, B, RE, and NIR bands) in this NASA funded pilot project. Water samples are being collected and analyzed for parameters relevant to HABs (May through November 2019) in Lake Winnecook, a seasonally impaired lake in Maine. Collected water quality data is being overlaid with UAV imagery (using spatial statistics) to look for correlation between the datasets. Validation of UAV imagery is further being substantiated by identifying specific algae types and concentrations present in water samples. The objective of this study is to assess and develop new water quality monitoring technologies operational at high spatial and temporal resolution. This work increases the intellectual and social capital that is engineered to produce solutions to combat environmental problems, while demonstrating environmental stewardship with new and environmentally responsible methods, offering a prototype for replication and expansion.

4:15 An Integrated and High-Speed Approach to Monitor Cyanotoxins
Frances Buerkens1, Hunter Adams2, Ashley Cottrell2, Sam Reeder2, Mark Southard2, and Harry Nelson1
1Fluid Imaging Technologies, Scarborough, Maine; 2City of Wichita Falls, Texas

Proactive drinking water agencies are seeking a streamlined approach to monitor cyanobacteria and the toxins they produce. Unfortunately, there is no single method that answers all the fundamental questions needed to make treatment decisions and ensure a safe water supply for recreating or drinking.

The City of Wichita Falls, Texas, designed and implemented a comprehensive integrated rapid monitoring protocol to monitor for cyanotoxins and taste and odor (T&O) compounds in two surface water reservoirs, one holding reservoir, and two water treatment plants. The procedure includes algae speciation and enumeration by FlowCam, T&O monitoring by GC-MS/ECD, and cyanotoxin monitoring by qPCR and LC-MS/MS.

As a result, the city mitigated one microcystin event and several episodes before water containing T&O compounds was discharged to the City’s residents. After three years since this strategy was implemented, customer complaints have been nearly eliminated. This presentation will provide other water systems with a cost-effective and time-sensitive blueprint for laboratory analyses to create their own protocol.

4:35 30 Years of Phytoplankton in a Drinking Water Reservoir
Joy Trahan-Liptak and Jamie Carr

Massachusetts Department of Conservation and Recreation, Division of Water Supply Protection, West Boylston, Massachusetts

Phytoplankton can impact drinking water supplies by clogging filters, creating undesirable odors, and exposing humans to harmful toxins. Many water suppliers conduct periodic algal monitoring; however, consistent long-term monitoring programs are rare. Phytoplankton have been monitored continuously since 1989 in Wachusett Reservoir, a surface water resource for Boston, Massachusetts. These data have been analyzed on short time scales; however, long-term assessment and correlation with physical and chemical water quality data available for the same time period has not been conducted. This study seeks to identify inter- and intra-annual variation in phytoplankton density and composition and primary climatic, water chemistry and environmental drivers of observed phytoplankton variation. The phytoplankton dataset includes > 5,800 individual samples collected from two reservoir locations at high frequency; most commonly at one-week intervals. Concurrent water column profiles were collected using multiparameter sondes to record temperature, dissolved oxygen, conductivity, and recently, chlorophyll a and phycocyanin. Watershed and reservoir nutrient data including ammonia, nitrate, silica, UV254, and total phosphorus collected at least quarterly are available for much of the study period. Preliminary analysis shows an increase in overall phytoplankton densities, particularly cyanobacteria, over the three decades. We predict these and other changes are related to climatic factors including increased temperature and other anthropogenic influences. Results of this study will assist water managers in prioritizing watershed protection activities, planning water transfers, and modeling future conditions. These conclusions may be extrapolated to the wider surface water supply and lake management community and demonstrate the advantages of long-term biotic assessments.


G4: Large-Scale Events

Moderator: Eli Kersh
Alligare, LLC, Richmond, California

3:35 Twenty-One Year Storm Flow Analysis on The South Platte River in Denver, Colorado
Nathan Jahns and Craig Wolf

GEI Consultants, Inc, Denver, Colorado

The Urban Drainage and Flood Control District partners with seven counties and three Phase I MS4 cities in the Denver metropolitan area to construct watershed flood control and warning measures. Stormflow water quality data has been collected since 1998 on the upstream (SPRU), center (SPRD), and downstream (SPRH) reaches of the South Platte River in the metropolitan area; and on two tributaries – Sand (SCRM) and Toll Gate (TGC6) Creeks.

From 1998-2018, 541 storm events were sampled. Mean total nitrogen (TN) and phosphorous (TP) were greatest at SPRH and specific conductance (SC) and total suspended solids (TSS) were greatest at TGC6. Mean values for all parameters were lowest at SPRU. Negative temporal trends (p < 0.05) were observed for TN at SPRH, TP at SPRD and SPRH, and TSS at SCRM and SPRH. Positive trends were observed for SC at SPRU, TGC6, and SCRM.

Storm loads were estimated at SPRD and SCRM for TN, TP, and TSS. Discharge data indicated a significantly decrease at SCRM. All parameter loads were greater at SCRM. Negative temporal trends were observed for TP and TSS at SCRM.

Water quality differences between sites is likely the result of residential and undeveloped land use in the drainage area and the 2013 flood which had the greatest impact on SCRM. Negative trends for TN, TP, and TSS are likely the result of management practices, such as storm water capture, largely associated with new developments. The increasing SC is the result of increased magnesium chloride from road salting.

3:55 Comparing the Efficacy of HAB Monitoring Technologies in NEPA Lakes; an Opportunity for Designer HAB Monitoring Strategies
Lauren Adkins Knose, Craig Williamson, and Erin Overholt

Department of Biology, Miami University, Oxford, Ohio

Harmful algal blooms (HABs) are expected to increase in occurrence and severity, especially across Northeast US, due to rising temperatures and precipitation. Several monitoring strategies have been proven effective in coastal waters and the Great Lakes; however, their efficacy in smaller inland waters has yet to be determined. This study was conducted in partnership with the Pocono Lakes Ecological Observatory Network (PLEON) compared proposed monitoring techniques for HABs in fresh, inland waters of Northeast Pennsylvania.

Ten lakes were sampled across trophic and DOM gradients in July 2019, from one-half meter below the surface. Water samples were analyzed for algal community composition via microscopy, potential toxic algal (PTOX) via Green Labs, quasi-quantitative microcystin concentration using ABRAXIS Quick Dip strips, quantitative microcystin concentration using the ABRAXIS ELISA Kit, total nutrients, total chlorophyll, and dissolved organic carbon concentration. Light, temperature and algal fluorescence profiles were obtained from the center of nineteen of the twenty lakes. This study provides unprecedented scientific data on toxin concentration across a DOM gradient, given that there is no published scientific data that measured toxin presence and DOM directly, and insight into the efficacy of the various monitoring strategies for lake managers to monitoring HABs within inland lakes.

4:15 Scales of Influence: Indications of High Intensity Precipitation Events in New Hampshire Lakes Using a Multi-Proxy Method
William Tifft and Lisa Doner

Plymouth State University, Plymouth, New Hampshire

Limnic systems, especially lakes, accumulate deposits, which can be used to interpret climatic, geologic, biologic, and anthropogenic watershed scale histories. Watershed processes operating across many different spatial scales can smooth and lengthen the distribution of sedimentary deposits related to individual historical events. Even very large events, such as hurricanes, can be masked by the mixing of “event sediments” with earlier deposits. We wonder will high intensity, short duration events can stand out above low intensity, long duration events and, if so, which proxy best documents that change?

This project addresses these questions to better understand the magnitude of precipitation needed to create distinct and recognizable deposits in lakes. Between the fall of 2017 and 2018, we used a 60 cm-long Uwitee gravity-corer to collect ten sediment cores, including the sediment-water interface, from four New Hampshire lakes: Newfound Lake, Bristol (1 core), Norway Pond, Hancock (2), Pleasant Lake, Deerfield (3), and Spofford Lake Chesterfield (4). The cores were subsampled at 0.5 cm or 1 cm intervals. Several physical and chemical properties were analyzed, including Pb210 age, stable isotopes, particle- size, frequency-dependent magnetic susceptibility, and mineral geochemistry. These data helped us identify sedimentary properties that correspond to episodes of regional flooding and terrestrial erosion, including two particularly high magnitude events for New Hampshire: Tropical Storm Irene, in 2011, and the Hurricane of 1938. The different sampling resolutions in side-by-side cores provide insight into the impact of sampling resolution on the detection of short duration, high-magnitude sedimentary responses to particular events.

4:35 Implementation of a Multi-Partner, Collaborative Effort to Manage and Monitor Post-fire Water Quality in a Large Northern California Lake
Angela De Palma-Dow1, Sarah Ryan2, Rich Muhl3, Gregg Dills4, and Amy Little5
1Lake County Water Resources Department, Lakeport, California; 2Big Valley Band of Pomo Indians EPA, Lakeport, California; 3California Regional Water Quality Control Board, Sacramento, California; 4Lake County Resource Conservation District, Lakeport, California; 5State Water Resources Control Board Division of Drinking Water, Santa Rosa, California

During summer 2018 the Mendocino Complex wildfire burned over 450,000 acres, geographically the largest fire in California’s post-settlement history. The burn scar was mostly located within the upper watershed of Clear Lake, a 303(d) listed nutrient impaired waterbody in Lake County and the state’s largest freshwater lake. Not only is Clear Lake home to sensitive floral and faunal species and supports traditional Native American uses, but Clear Lake provides drinking water to 40,000 residents and activities such as fishing and recreational boating generate substantial tourism dollars. A multi-partner, interagency collaborative post-fire action plan was immediately implemented to identify 1) locations most likely to contribute post-fire pollutant and sediment loads 2) locations most likely to benefit from on-the-ground best management practices to limit post-fire impacts and, 3) best stream and lake sample sites to monitor post-fire water quality. This paper will discuss development of this effort, specific actions implemented, outcomes, and status of Clear Lake. Conclusions from this effort might be useful to organizations and agencies when partnering and collaborating on management and monitoring in freshwater systems with large or impaired waterbodies, of which current post-fire water quality research is limited.


G5: Aquatic Invasive Species V – Prevention and Management

Moderator: Meg Modley
Lake Champlain Basin Program, Grand Isle, Vermont

3:35 Adirondack Aquatic Invasive Species (AIS) Management Tracker Program: A Citizen Science-Based Monitoring Program to Track the Effectiveness of AIS Management
Erin Vennie-Vollrath1 and Leigh Walrath2
1The Nature Conservancy, Adirondack Park Invasive Plant Program, Keene Valley, New York; 2Adirondack Park Agency, Raybrook, New York

Lake associations in the Adirondack Park region of New York have been managing Eurasian watermilfoil and other AIS for decades. The majority of the associations rely on contracted private enterprises to undertake the actual management using diver hand harvesting. A year-end report is typically provided to document the areas managed, the volume of material removed, and the duration (i.e., number of days, total dive hours) of management. The reports usually provide a narrative description regarding overall lake condition. However, these lake-wide assessments tend to be short observational assessments and they are focused solely on the invasive species being managed. They do not provide an effective means to measure invasive species management progress over long periods of time, nor do they provide a means to understand the distribution and abundance of native vegetation, and changes to the native population over time. The citizen science-based survey addresses this void, thereby allowing for a more informed management decision and it can serve as a bridge between infrequent professional plant surveys and the year-end report produced by the contractor.

3:55 The Starry Stonewort Collaborative for the Great Lakes Basin
David Carr, Hilary Mosher, and Lisa Cleckner

Finger Lakes Institute at Hobart and William Smith Colleges, Geneva, New York

Starry Stonewort (SSW, Nitellopsis obtusa) is an aquatic invasive macroalgae from Eurasia that closely resembles a vascular plant. It invades lakes, ponds, and slow-moving water bodies where it attaches to the sediment using rhizoids and grows to 2m (Kipp et al. 2017).

Left unchecked the SSW will cause harm to natural environmental systems and inhibit use of waterways, which can potentially result in economic impacts.

The Collaborative will enhance the capacity of experts, resource managers and local stakeholders to address starry stonewort infestations.

A key component of the project is a network of 23 scientists, stakeholders and resource managers and 8 Expert Panelists from across the Great Lakes basin who will help with outreach, resource exchange and project facilitation.

Collaborator and panelist work will be applied to three focus areas:

    • Ecology – sharing of ongoing field work and laboratory research for better understanding of Nitellopsis obtusa characteristics and life cycles
    • Outreach – providing insights into the best outreach and education strategies for community involvement in SSW identification and reporting
    • Control – assisting in gathering and sharing best management practices and techniques from all areas of the GLB

Expected outcomes include:

    • engagement and training target of 1000 community level volunteers across the GLB
    • development of a dedicated SSW website and online library
    • creation and dissemination of BMPs for infestations of SSW throughout the GLB
    • development and distribution of factsheets describing SSW and its control
    • creation and implementation of prevention strategies
    • rapid assessment and response plans
4:15 Lessons Learned: Perspectives on Managing Quagga Mussels in the Lower Colorado River
Heidi McMaster1, Erin Raney2, Barak Shemai3, Nathan Owens4, and Theresa Thom5
1US Bureau of Reclamation, Boulder City, Nevada; 2Arizona Department of Fish and Game, Phoenix, Arizona; 3US Fish and Wildlife Service, Albuquerque, New Mexico; 4Utah Division of Wildlife Services, Salt Lake City, Utah; 5US Fish and Wildlife Service, Portland, Oregon

Quagga Mussels have had a great economic effect in the Lower Colorado River. Since the discovery of bivalve mussels in Lake Mead in 2007, Reclamation and other partner agencies have worked diligently to contain the quagga mussel threat. To assist states and other communities who do not currently have quagga mussels or zebra mussels, Reclamation worked with coordinating agencies along the Colorado River to discuss lessons learned, good or bad, in managing the mussels. These lessons include, early coordination and partnership building; early communication and communication plans; early infrastructure inspections; outreach and education; and state and legal support frameworks. Every state and agency are managed differently, but it is the idea of this lessons learned to provide assistance to others before quagga mussels or other invasive species become an economic hardship.

4:35 Trends in Beach Closures, E. coli, and a Shift in Dominance From Zebra to Quagga Mussels on a Large Canadian Lake
Melissa Moos1, Richard Meldrum1, and Brian Ginn2
1Ryerson University, Toronto, Ontario, Canada; 2Lake Simcoe Region Conservation Authority, Newmarket, Ontario, Canada

Lake Simcoe is a large (surface area 722 km2) lake in south-central Ontario that has a variety of economic and recreational uses including fishing, boating, and swimming, as well as being the drinking water source for eight communities. In the early 1990s, zebra mussels (Dreissena polymorpha) invaded the lake and quickly became the dominant benthic species, restructuring the lake food web and being partly responsible (along with phosphorus reduction strategies) for a two-fold increase in water clarity. In 2004, quagga mussels (D. rostriformis bugensis) were recorded in the lake for the first time and have since replaced zebra mussels as the dominant benthic species. In addition, quagga mussels have further re-structured the lake food web, channeled more energy to benthic profundal habitats, and fouled deep water infrastructure, such as drinking water intakes. Other locations in the Great Lakes Region have shown decreased E. coli concentrations and a reduction in recreational beach closures as a result of a similar benthic shift. This study investigates CFU/ml of E. coli and beach postings/closures for a number of areas in Lake Simcoe for pre- and post-quagga mussel invasion. Although the number of advisories on many beaches was similar for both periods, the length of posting decreased post-quagga invasion. As well, a reduction in the geometric mean (minimum of five samples of less than 200 E. coli per 100ml) is lower post-quagga invasion, suggesting that the shift to quagga mussel dominance has had an impact on water quality and beach postings in Lake Simcoe.


G6: Non-Algal Toxins

Moderator: Victoria Chraibi
Tarleton State University, Stephenville, Texas

3:35 Use of Geological Approaches in Determining the Source, Transportation Pathways and Food Chain Impacts of Recent DDT Contamination in Squam Lake, New Hampshire
Amanda May and Lisa Doner

Plymouth State University, Plymouth, New Hampshire

Elevated concentrations of DDT, 48,000 times background levels, were detected in surface sediments for an inlet into Squam Lake, New Hampshire in 2017 (pers. comm., Loon Preservation Committee). It drains a watershed dominated by apple orchards from the 1920s to 1950s that used DDT. Today, erosion associated with flooding, mass wasting of riverbanks or beaver pond scouring may be mobilizing sediments and soils that had stored and preserved remnants of the DDT applications. To determine contamination source areas, I use Gas Chromatography to analyze DDT in strategically collected soil and sediment samples. The timing of recent inputs of DDT to the lake is determined by freeze coring just outside the mouth of the stream and is established by dating and high-frequency analysis of the sediments for DDT. The dates of first re-occurrence of DDT are compared to meteorological records of extreme precipitation and watershed erosion events, and to historical records of land use to establish the probable trigger for this contamination issue. To determine if new DDT has entered the aquatic food chain, I test crayfish for DDT, because they are low on the food chain and reside in the DDT-laden sediments. Results (so far) indicate the highest DDT concentrations in the stream sediments are located slightly downstream of NH RT 113. Also, the presence of DDE, but not DDT, has been detected in the lake sediments. This study calls attention to possible ongoing threats of persistent contaminants like DDT, despite bans in use decades ago.

3:55 Natural Recovery of Lead Contamination in Sediments at Lewis Lake, Yellowstone National Park
Stephen Klein

Benthica, Elizabeth, Colorado

A parkwide study of automotive metal contamination in Yellowstone National Park that began in 1984, revealed that lead concentrations in sediment at Lewis Lake had two peaks in the recent past that were 7 times the natural concentration. Sediments cores were dated with Pb210, Cs137 and biogenic silica, and the concentration peaks correspond to peaks in atmospheric emissions from smelters in the 1920s and automobiles in 1970. A two-year mass balance was performed on the lake to quantifying all sources, transport pathways and losses. A mechanistic model was developed and calibrated to the data. The profile of lead concentrations in sediment was used in the model to deconvolute the relative magnitudes of natural, smelter and automobile sources. Finally, the model was used to predict long-term recovery towards natural concentrations. The model predicted that concentrations would not drop to within 10% of natural for more than 1000 years, but that after 20 years the concentration in settling particles would decrease about 4–5 ppm. To test model predictions, sediment traps were deployed, and cores collected in 2007. Sediment cores showed that the older peaks were buried an additional 2 cm, and that surface concentrations decreased to about twice natural. Trap material had decreased by the predicted 4 ppm. Even though automobile and smelter emissions are now essentially zero, past deposition of lead to the soil in the watershed continues to contribute a significant portion of lead to the lake.

4:15 PFAS – How Is It Entering Lakes and Reservoirs
Richard Desrosiers

GZA GeoEnvironmental, Inc, Glastonbury, Connecticut

PFAS is comprised of 100s of compounds that have been in used since the 1950s. PFAS has become ubiquitous in the environment including lakes and reservoirs. Unlike other more familiar contaminants, PFAS can contaminant surface water through industrial, municipal, (including wastewater treatment systems) and groundwater, surface water run-off and even from atmospheric particulates. Special sampling protocols are required because of its molecular structure and that PFAS is in many of our everyday products that can lead to cross-contamination resulting in false positives, especially when measuring in the parts per trillion. This presentation will explore the fate and transport mechanisms of how PFAS can enter surface water bodies.

4:35 Mercury Increase in Lake Champlain Fish May Be Linked to Extreme Climatic Events
Mark W Swinton and Sandra A. Nierzwicki-Bauer

Rensselaer Polytechnic Institute, Troy, New York

Mercury concentrations in Lake Champlain fish increased (2011–2017) for the first time in more than two decades. The increase, however, was not consistent among species or throughout the lake. Mercury concentrations in smallmouth bass and yellow perch from the three Main Lake segments increased significantly while concentrations in the western portions of the lake (Northeast Arm and Malletts Bay) remained unchanged or decreased; mercury concentrations in white perch remained unchanged. Examining possible contributing factors for the increase, which included: atmospheric deposition, lake temperature, chlorophyll a, pH and dissolved organic carbon, along with tributary loading of total suspended solids (TSS) and the invasive alewife identified TSS to be at least partially responsible for the increased fish mercury. Two extreme climate events in 2011 resulted in a four-fold increase in annual TSS loading and associated mercury. The Main Lake segments exhibited significant mercury increases in fish and received the majority of TSS loading to the lake. The Northeast Arm exhibited no change in fish mercury concentrations and does not drain any major watersheds resulting in very low TSS loading. Fish mercury concentrations in Malletts Bay have either decreased or remained unchanged and while it does receive TSS from a major watershed, it has severely restricted circulation resulting in seasonal hypoxia, which may overshadow the additional mercury loading. If extreme climatic events can significantly increase fish mercury concentrations, it is important to study processes affected to better prepare for possible changes to the mercury cycle, particularly in a future with more extreme climatic events.