Water Resources Conference - October 18, 2022

Moderator: Greg Wilson
Co-moderator: Kimberly Hill

10:00–10:20 – 1034: Pricey or Practical? Implementation and Operation of Pumps and Automation in Sand Filters

Alex Schmidt, Houston Engineering; Kyle Axtell, Rice Creek Watershed District; Mike Behan, Dakota County

Urban stormwater managers face a challenge when looking to implement stormwater treatment practices to meet their pollutant load reduction goals. The challenge is that landscapes are fully developed, leaving little room for treatment systems, or forcing systems underground, which becomes expensive. Pumps have often been avoided in stormwater treatment given their stigma of being expensive, impractical, and requiring more effort to operate and maintain.
 
 Houston Engineering has supported the evaluation and implementation of stormwater treatment sites with pumping and automation for multiple organizations (including the Rice Creek Watershed and Dakota County). A multitude of automation and flexibility options in the design of these pumping systems allows for innovative applications of traditional stormwater management practices such as the dry-wet cycling required for iron-enhanced sand filters (IESF), even within the context of continuous flow. This flexibility can overcome many obstacles to effectively capture dissolved phosphorus in stormwater runoff. During feasibility phases, pumping and automated systems were compared and contrasted with more typical passive treatment systems, and evaluated for treatment performance, cost-effectiveness, relative footprint size, and operation and maintenance needs. The results of the system comparisons will be shared along with practical aspects related to their design, construction and operation.

10:20–10:40 – 1035: Pollutant Removal and Maintenance of Underground Sand Filters

Todd Shoemaker, Stantec

The purpose of this study is to evaluate the stormwater management effectiveness of installed underground sand filters in the Twin Cities Metro Area. The Minnesota Stormwater Manual includes guidance for the design and pollutant removal efficiency of surface and one type of underground sand filters. The most popular variety of underground sand filter, however, does not offer clear access to the sand media layer and is not included in the Minnesota Stormwater Manual. Maintenance is extremely limited by this design, which calls into question whether they can actually achieve the same removal efficiency as their above-ground counterparts, and whether those efficiencies degrade over time. There is limited data regarding performance of in situ underground sand filters to assist in this evaluation.
 This presentation will summarize research data collected during 2020 and 2021 for six underground sand filters. The data will give some indication whether these systems meet performance goals and if these systems should continue to be considered a viable water quality BMP.

10:40–11:00 – 1039: Experimental Field Trial of Media for a Modified Iron-Enhanced Sand Filter

Andy McCabe, Keith Pilgrim, Janna Kieffer, Barr Engineering Co.

A drawback of many iron enhanced sand filters (IESFs), which are being constructed across Minnesota, is the slow filtration rates (approx. 3-4 inches per hour) and the corresponding effect that the filters need to be large when receiving runoff from large watersheds. To reduce external phosphorus loading to Lake Cornelia, the Nine Mile Creek Watershed District, in partnership with the City of Edina, is constructing an active stormwater filtration best management practice (BMP) located in Rosland Park. Because the BMP needs to treat large volumes of water, but have a small footprint to preserve greenspace within the park, the design solution was to employ fast filtering media and site the BMP directly adjacent to a holding pond upstream of Lake Cornelia to serve as the water source.

A column study was conducted on-site to simulate BMP operation and identify media that could rise to the challenge of rapid phosphorus treatment. This field study evaluated 10 media and media combinations, including calcium, iron, and aluminum-based media. The removal efficiencies of total phosphorus, dissolved phosphorus, and orthophosphate were evaluated for each media at three different hydraulic residence times (HRT).

Results from this column study will be presented. In general, this study demonstrated that high removal efficiency can be achieved with high filtration rates. Phosphorus removal efficiencies varied widely between the tested media, with highest removals observed for media with zero-valent iron (e.g., iron-enhanced sand) and activated alumina. These results served as the basis for the selection of media installed in the full-scale filtration BMP.

11:00–11:20 – 1040: Can Biofilters Capture Phosphate and Grow Plants?

Andy Erickson, Katie Kramarczuk, Jessica Kozarek, St. Anthony Falls Laboratory, University of Minnesota

Biofilters can be used to treat stormwater runoff from urban landscapes, but some media used in biofilters can release phosphate or limit plant growth. As such, stormwater professionals struggle to choose media for biofilters. To address this question, thirty outdoor biofiltration mesocosms comprising nine different media mixes were compared to clean washed sand for capture (or release) of phosphate, plant growth, and filtration rate. Media components included food residue compost, leaf compost, sphagnum or reed sedge peat, biochar mixed with leaf compost, spent lime mixed with leaf compost, iron mixed with leaf compost, sphagnum peat mixed with leaf compost, and compost layered over iron. This presentation will share the near-final performance results from four rainy seasons of simulated runoff events including new-for 2022 road-salt-laden events to simulate spring snowmelt in Minnesota. With the information from this study, stormwater practitioners will be able to design better biofiltration practices that capture phosphorus and support healthy vegetation while also maintaining adequate filtration rates.

11:20–11:30 – TBD

Moderator: Jared Trost
Co-moderator: Dave Wall

10:00–10:20 – 1004: Advancing Water Quality and Conservation through Climate Smart Bridge Payments to Farmers

Brad Jordahl Redlin, Danielle Isaacson, Minnesota Department of Agriculture—Water Quality Certification Program

The developing arena of agriculture and climate mitigation is dynamic, and in many respects unsettled relative to the efficacy of certain agricultural practices, the performance of private marketplaces, and the federal government’s role in new programs. The Minnesota Agricultural Water Quality Certification Program’s (MAWQCP) Climate Smart Farms Project recognizes the connection between water quality protection and climate benefits and responds to this relationship with a model of one-to-one personal service and support to producers exploring climate actions on their farms. This new program provides $1,000 annual bridge payments for up to 5 years to producers who receive an MAWQCP Climate Smart Endorsement. Endorsed producers must successfully complete a climate audit to be sure their practices meet climate smart baselines. The purpose of the bridge payments is to support producers in exploring and implementing new practices that could be introduced on farm to reduce emissions, with support from MAWQCP staff. In addition to learning about and utilizing new management practices, enrolled producers will have access to information about carbon markets and other environmental trading opportunities that will prepare the climate-smart endorsed producers to participate in carbon credit markets. Sharing these resources, documenting existing practices, and incentivizing new practices sets the Climate Smart Farms Project up to help producers increase the climate benefits their operations provide.

The successes and lessons learned from the Climate Smart Farms Project will inform future policy around incentivizing agricultural practices that reduce emissions, sequester carbon, and protect water quality, contributing to a more resilient agricultural system in the face of climate change. By understanding new opportunities and documenting current practices we will ensure no loss of existing climate and water benefits while facilitating the implementation of new ones.

10:20–10:40 – 1006: Cover Crops and Living Mulches Effects on Irrigated Corn-Soybean Production Systems: An Integral Nutrient, Water, and Environmental Management Strategy

Eduardo Garay Lagos, Fabián Fernández, University of Minnesota

The state of Minnesota, USA has over 240,000 ha of irrigated glacial outwash sands that are predominantly under corn and soybean cultivation. While highly productive and important to Minnesota’s economy, these soils are highly vulnerable to concomitant losses. Therefore, farmers are encouraged to go beyond a traditional production approach by implementing the use of sustainable cultural practices such as cover cropping. Nevertheless, there is limited research aiming to holistically understand their effect on N cycling (N availability, nitrate leaching, nitrous oxide emissions and ammonia volatilization) and competition with corn and soybean for resources under irrigated conditions. This study was established in 2011 in an irrigated sandy loam soil at Westport, Minnesota. Three adjacent blocks of continuous corn (CC), corn-soybean (CSb) and soybean-corn (SbC) cropping systems were used. Treatments included N fertilizer rates of 0, 100, 200, 250 and 300 kg N ha-1 split-applied at V2, V6, and V10 development stages of the CC and CSb while no N was applied in the SbC. Each N rate had winter-rye (Secale cereale) and winter fallow. Kura clover (Trifolium ambiguum M. Bieb.) living mulch was present in the 0, 200 (CSb only) and 250 (CC only) kg N ha-1 rates. Results from this comprehensive assessment will include nitrate leaching concentrations and load, nitrous oxide and ammonia emissions, season-long soil N availability, crop N uptake, and grain yield. This study aims to discover improved strategy in nutrient and water management to optimize agronomic production while substantially minimizing agricultural environmental impact.

10:40–11:00 – 1010: Enhancing the Prioritize, Target, and Measure Application (PTMApp) User Experience

Scott Kronholm, Houston Engineering Inc.; Matt Drewitz, Minnesota Board of Water and Soil Resources

The Prioritize, Target, and Measure Application (PTMApp), supported by BWSR, underwent a major update in the latter half of 2020. This update saw a shift away from the six generic BMP treatment groups (e.g., storage, filtration, etc.) to 24 NRCS-based practice types (e.g., WASCOB, riparian buffer, etc.). The increased specificity allows users to more clearly define suitable areas on the landscape and estimate water quality benefits specific for each individual practice type.

Subsequent enhancements have been implemented to support common uses of the vast amount of PTMApp data. Several stand-alone tools have been created to help users utilize existing PTMApp data or to expand the existing functionality of the PTMApp toolbar. One of the new tools allows users to condense and summarize data for a specific subwatershed or planning area, streamlining the process of targeted watershed planning. A second tool was built using watershed-specific PTMApp data to summarize expected water quality benefits of implemented practices based on the simple user input of total treated acreage per practice type. The beta version of this tool is currently presented as an interactive Microsoft Excel spreadsheet. The final tool allows users to input digitized GIS polygons representing existing or future practices into the PTMApp architecture to estimate benefits of those practices using the underlying PTMApp data and processing framework.

The interactive PTMApp-Web application simultaneously made the shift to NRCS-based practices where updated watershed data are available. And a new PTMApp-Web scenario builder widget was created that allows users to generate targeted implementation scenarios with user defined screening criteria for various parameters.

These enhancements were made with the end-user in mind in an effort to streamline and simplify PTMApp data extraction, manipulation, and interpretation and to reduce barriers to entry when using the PTMApp software and data.

11:00–11:20 – 1012: The Potential for Improving Water Quality and Habitat in Minnesota by Repurposing Unprofitable Cropland with Perennial Vegetation

Jason Ulrich, Shawn Schottler, Science Museum of Minnesota, St. Croix Watershed Research Station

Our current agricultural conservation approaches have not met Minnesota’s water-quality or habitat goals. In fact, despite investing millions of dollars in best management practices, water-quality has not improved demonstrably. At the same time, increases in corn and soybean acres and changes in agricultural practices have resulted in dramatic declines in grassland habitat critical for migratory birds and pollinators.

Replacing corn and soybeans with perennial vegetation systems such as alfalfa, wetlands or restored prairie is a very effective means of improving both water-quality and habitat, but thus far has been economically impractical to implement at scale because it usually requires taking profitable cropland out of production.

However, based on Midwestern studies, it is likely that 1 million acres or more of cropland in Minnesota has been unprofitable (i.e., broke even or lost farmers money) in some or all of the last five years. Thus, targeting these unprofitable cropland areas is potentially the cheapest way to increase perennial vegetation in Minnesota.

Our study explored this concept by mapping the probable extent of unprofitable cropland in the southern one-third of Minnesota over the last 5 years, and estimating both the water-quality and habitat benefits of converting different fractions of these areas to perennial vegetation.

The study results underscore the importance of targeting unprofitable cropland for cost-effective conservation approaches. Further, the concept could be used to develop future policy incentives to significantly increase perennial vegetation in Minnesota’s agricultural areas.

11:20–11:30 – TBD

Moderator: Jack Distel, City of Bloomington
Co-moderator: Keller Leet-Otley, Kimley-Horn

This workshop will build collective wetland knowledge and increase understanding of how wetlands integrate with overall water resources management throughout the Midwest. The presentations of this year’s workshop could include topics about the storage dynamics of peatlands, nutrient influence of wild rice, and updates from the Minnesota Board of Water and Soil Resources. The workshop was developed in coordination with the Minnesota Wetland Professionals Association.

10:00-10:20 – BWSR Updates

Ben Meyer, Minnesota Board of Water and Soil Resources

10:20-10:40 – 1054: Dynamic Storage in Peatland Catchments

David J. Adams, Salli F. Dymond, University of Minnesota Duluth

Analysis of the catchment water balance often relies on the assumption that changes in storage are generally static from year to year and therefore negligible. However, interannual variability in catchment storage may be a key component of the water balance in particularly wet or dry years. This study aims to assess dynamic water storage at the Marcell Experimental Forest (MEF) in three ways; (1) analyze the effect of annual variability in precipitation on annual storage flux, (2) analyze the effect of antecedent annual precipitation on catchment dynamics in subsequent years, and (3) analyze the extent to which particularly dry or wet years influence storage flux in subsequent years. These questions will be addressed via statistical analysis of long term hydrologic data sets using the R statistical software environment. It is expected that positive and negative variations around mean annual precipitation will result in positive and negative growth in storage respectively while past precipitation will exert a lagged influence on storage flux in subsequent years. It is also expected that any lag effect will be more pronounced following particularly wet or dry years. This project is being conducted in partial fulfillment of the requirements for the degree of Master of Science at the University of Minnesota; preliminary results are expected in the Fall of 2022 with a projected completion date of May 2023.

10:40-11:00 – 1026: Wild Rice Populations Recover Quickly in Mesocosms in Response to Lower Sulfate Loads in Surface Water

Nathan Johnson, John Pastor, Brad Dewey, Leah Higgins, University of Minnesota Duluth; Sophie LaFond-Hudson, Oak Ridge National Lab

Numerous observations from field scale to mesocosm scale to lab scale have established that sulfate in surface water limits the growth of wild rice in lakes and rivers. The conversion sulfate to sulfide in sediment interferes with the ability of wild rice to take up nitrogen and has led to population declines over 3 to 10 years in self-sustaining outdoor mesocosms, depending on the level of sulfate addition. In this presentation, we report the preliminary results from an experiment that removed sulfate from the surface water of mesocosms that had experienced 5 to 10 years of sulfate loading and observed the response of wild rice recovery. In mesocosms amended with 300 mg/L sulfate in surface water, plant populations recovered to biomass levels and seed mass similar to control mesocosms in 3 to 4 years. In mesocosms amended with 150 mg/L sulfate in surface water, plant populations recovered in only 1 to 2 years. This relatively rapid recovery occurred with no addition of new seeds and apparently was initiated by a latent seed stock in the sulfate-impacted sediment. The concentration of porewater sulfide in mesocosm sediment dropped precipitously in response to lower sulfate loads from surface water but still remained above the levels found in control mesocosms and lower sulfate amendments. Solid phase sulfide remained elevated during the recovery phase of the mesocosm experiments, suggesting that the total mass of sulfide in sediment is less important than the activity of sulfide in sediment porewater. Though the pace of recovery could be different in field conditions, these preliminary results suggest that lowering sulfate loads to surface waters could result in relatively rapid re-establishment of wild rice populations, even in waterbodies where sediment has been heavily impacted by historic sulfate loading.

11:00-11:20 – Phragmites Reporting Tool and Management

Julia Bohnen, University of Minnesota

WPA Updates

Keller Leet-Otley, Kimley-Horn; Jack Distel, City of Bloomington

11:20–11:30 – Q&A

Moderator: Marcey Westrick
Co-Moderator: Tracy Fallon

10:00-11:00 – Transforming Water Management through the Arts

Abby Moore, Mississippi Water Management Organization; Sarah Nassif, Artist; Christine Baeumler, Artist; Lindsay Schwantes, Capitol Region Watershed District

This session will focus on integrating art and artists into community engagement strategies to achieve clean water goals. A panel will highlight recent examples of how this collaboration is enriching and transforming their work. Following the panel, attendees will have an opportunity to explore together how art and artists may enhance their programs and projects. The session will end with an artist-led project and something for all attendees to take with them.

Moderator: Tina Carstens
Co-moderator: Emily Resseger

1:15–1:35 – 1045: MS4 Program Management, Everything Is Better with Apps

Nico Cantarero, Stantec

For those in the MS4 world, the umbrella permit can put you front and center to a lot of different and exciting things in the water resources field. But it’s universally known that the documentation, tracking, and annual reporting are quite a drag. Luckily, everything is better with apps!

This presentation will highlight different tools available to MS4 program managers that can be used to digitize and streamline their program, and ultimately put that data to good use. And with the built-in tools, you can automate reports to make reporting easy. All the tools highlighted in this presentation are publicly available and widely used (e.g. ESRI Survey123/Field Maps/Dashboards, Smartsheets, Fulcrum) and are not proprietary to Stantec.

1:35–1:55 – 1066: Optimism, Ignorance or Foolishness: Are We Setting Practical Water Quality Goals?

Mark Deutschman, Charles Fritz, International Water Institute

Our work as resource professionals - whether striving to improve habitat for game species, manage runoff to reduce flood damages or improve water quality to restore beneficial uses - requires establishing goals. A well-crafted goal clearly describes the expected resource outcome(s) and corresponding benefit(s). Goals are the foundation for assessing the success of resource programs.

Whether it is One Watershed One Plan, a Total Maximum Daily Load, or a state-wide strategy to reduce nutrients in runoff, developing well-crafted goals is challenging. Well-crafted goals are: 1) technically feasible; 2) described in terms of specific outcomes and the expected public benefits; 3) achievable within a reasonable amount of time; 4) attainable given the available human and technical resources; and 5) affordable. Well-crafted water quality goals lead to sound resource management decisions, credibility within the lay community and continued public support to improve water quality.

Our presentation focuses on developing good, robust water quality goals for improving water quality. We highlight the resource implications of common challenges associated with setting lake and stream water quality goals. We describe a robust process for establishing water quality goals based on defining success, the amount of scientific uncertainty, the level of public transparency, the ability to track progress, local implementation capacity and the available fiscal resources. The presentation includes examining the value of using the recommended approach.

1:55–2:15 – 1067: Metropolitan Council’s Priority Waters List: A Tool for More Effective Water Resources Management

Emily Resseger, Erik Herberg, Henry McCarthy, Metropolitan Council

The Metropolitan Council recently adopted a Priority Waters List to guide its water resources partnerships and work efforts. The Met Council works with city, county, watershed, state, and federal partners in the Twin Cities metro area to manage water resources through monitoring, assessment, planning, and implementation of projects. Given the large number of waterbodies in the region, it is infeasible for the Met Council and its partners to effectively monitor and evaluate all waterbodies regularly. The Priority Waters List allows the Met Council to focus its resources on waterbodies that offer the greatest benefit to the region.

The Priority Waters List updates the Met Council’s previous Priority Lakes List by expanding it to include rivers and streams and by considering a broader range of benefits. The new list prioritizes waterbodies determined to be regionally significant based on the benefits they provide in seven categories: Drinking Water Protection, Recreation and Tourism, Healthy Habitat, Tranquil Connection, Equity, Industry and Utility, and Science and Education. Waterbodies were scored in the seven categories using over 70 datasets that were either publicly available or created for the project.

By focusing the Met Council’s resources on waterbodies that provide the greatest benefit, the Priority Waters List will allow the Met Council to do its work more effectively and efficiently. The list is anticipated to be used in the near term to focus planning efforts in Met Council’s upcoming 2050 Water Resources Policy Plan, guide Met Council monitoring and assessment work, be considered in Met Council’s environmental reviews and grant selection process, and be a resource for local partners.

This talk will outline the innovative approach used to establish the Priority Waters List, present the overall list as well as sub-lists showing priorities in individual categories, and discuss potential uses for the list, both by the Met Council and its partners.

2:15–2:35 – 1071: Thousands of BMPs? How to Best Manage and Prepare for Maintenance

Laura Wehr, AE2S; Kristin Seaman, City of Woodbury

Today’s BMPs provide increased water quality benefits but also require different maintenance. This presentation will walk through how one community updated their BMP program to meet the maintenance needs of new BMP types. The overall goal of the presentation is to better educate individuals how to set up or modify existing maintenance programs that ensure all BMPs types are included.

Woodbury is one of the fastest growing cities in Minnesota. As part of the development process, the City requires stormwater management best practices (BMPs) to be installed, which has led to over 1,700 city owned BMPs within Woodbury. As the City’s BMP system has expanded so have the stormwater regulations and the complexity of BMPs being used. These changes created an opportunity for the City to step back from regular pond dredging projects and reconsider the system in its entirety. The result was the Woodbury BMP Maintenance Plan which takes a holistic approach at managing every part of the public stormwater system to meet the requirements within the current MS4 permit, manage the resources responsibly, and do so cost efficiently.

City staff from various departments worked together over the course of a year to understand the system, identify any challenges, and review best practice recommendations from external and internal sources to create this plan. The presentation will share specific examples about findings from these collaborations.

Developed in collaboration with this plan are three guides for the City to use: an Inspection and Maintenance Framework and Guides for each BMP type, a public engagement plan, and a cost estimation model. The findings from these guides will be shared in order to show how plan concepts can be turned into usable materials.

The Plan was published in October 2021 and the City completed their first annual BMP maintenance project using the plan in Winter 2021/2022. Results from the initial use of the plan will be included in the presentation.

2:35–2:45 – TBD

Moderator: Salaam Murtada
Co-moderator: Ryan Johnson

1:15–1:35 – 1019: Soil Health of New Construction Soils in Roseville and Lessons in Compost Topdressing

David Bauer, Alliant; Ryan Johnson, City of Roseville

Roseville recently built a new city trail on fill soils. It became the perfect place to start a three-year soil health study, in partnership with Ramsey County and the Ramsey/Washington Recycling & Energy Center, on the effects of compost topdressing. The first year of the study established the soil properties of a new construction soil as well as tested methods of compost application. The city hopes the compost will improve infiltration and vegetation resilience in drought, establish another use for a waste product, and increase carbon sequestration.

The Universities of Minnesota and Nebraska (Kearney) each tested the soil for fertility and organic matter. Nebraska used the Haney Test to measure soil health, which includes a measurement of microbial respiration. Infiltration was measured in the field using an Amoozemeter.

The initial testing confirmed some common beliefs of about the degraded nature of new construction soils, but also revealed a couple of surprises. These new soils were relatively low in organic matter, high in nutrients, low in soil microbes, and low in infiltration. In the month between grading and testing, organic matter had already migrated enough to show differences when measured at the bottom of the slopes and top of the slopes.

It took less than two hours for 16 volunteers to spread a truckload of compost, using two different styles of hoppers and wheelbarrows. Two half-inch rain events pushed the fine compost into the blanket, leaving woody fibers on the surface.

1:35–1:55 – 1020: Linn Grove Dam: A Tale of Adapting Design to Existing Infrastructure, Climate Change, and Community Expectations

Derek Lash, Emmons & Olivier Resources, Inc. (EOR)

The Linn Grove Dam is located on the Little Sioux River in Buena Vista County, Iowa (approximately four hours southwest of Minneapolis). Originally built in 1875 to divert water to an old mill, the dam and associated infrastructure have been damaged and repaired numerous times in response to flood events, which are expected to continue to increase in frequency as climate change continues.

The 1600 square mile drainage area flowing to the dam has caused undue stress on the dam as it has aged, and the recent events were no different. In late 2018 and early 2019 the Little Sioux River in Linn Grove experienced record setting floods. These floods were so great, a new river channel was cut around the low head dam at Linn Grove Dam Park, rendering the dam and park useless. The peak flows were more than 21,000 cfs, with the dam and entire 1/4-mile-wide floodplain under significant water. It is estimated at the time of the flooding, the river stage upstream was 18 feet higher than baseflow conditions and there was more than eight feet of water flowing over the dam. Today the dam sits high and dry, and the river is unusable due to the low water levels and the amount of tree debris and sand that was deposited during the flood.

This presentation will discuss the first phase of work focusing on the engineering studies and designs that intend to repair damages to the channel and infrastructure and increase dam and channel stability during flood events. We will discuss the historical records reviewed, as well as the recent due diligence completed to determine the dam condition and a preferred route for repairs. Design elements discussed will include sheet pile cutoff walls, rock arch rapids, streambank stabilization, and numerous park improvements to reintroduce the community to the dam and the river. The discussion will also include challenges with the design, permitting, funding, and determining a suitable time frame for construction.

1:55–2:15 – 1021: Calibrating the Cannon River: Gridded Precipitation and HEC-HMS Modeling in a Lake-laden Watershed

Brady Nahkala, Roberta Cronquist, Bolton & Menk, Inc.

The upper lobe of the Cannon River Watershed stretches west of Faribault through significant portions of Rice and Le Sueur Counties. Towns along the river, including the City of Waterville, have experienced repeated flooding within the past 10 years due to increasing intensity and timing of storms as rainfall patterns continue to change in the region. The purpose of the current study is to better define existing flood risk along the Cannon River and within the watershed, with future plans to develop recommendations for regional flood improvements and/or regional watershed management strategies to improve flood resiliency in the region, and install a new flood forecast gauge upstream of Waterville.

As part of the study, an existing conditions HEC-HMS model was calibrated to assess flood flows and reservoir levels along the river. Influencing the hydrologic and hydraulic regime of the ~330 sq. miles draining to Faribault are 17 jurisdictional dams, numerous other hydraulic structures, and significant natural storage within the basin. The model was calibrated and validated to four sets of gridded storm data for severe events occurring between 2011 and 2017 within the watershed. Prior modeling efforts by the USACE were leveraged and built upon to add resolution to hydrologic and hydraulic inputs, including modeling an additional 18 reservoirs and/or reservoir outlet structures along the river and its contributing basins. Dams and other structures were found to have significant influence on basin hydrology, requiring the iterative development of HEC-RAS models and the gridded HEC-HMS model for adequate calibration. This presentation discusses those efforts in what the USACE previously described as the “most complicated subbasins to model.”

2:15–2:35 – 1022: Adapting Stormwater Infrastructure in the Face of Climate Change

Noah Gallagher, Andy Erickson, John Gulliver, St. Anthony Falls Laboratory, University of Minnesota

Extreme rainfall events changing rainfall distributions and recurrence frequency have significant impacts to urban landscape design, stormwater runoff management, and flood control. This presentation will cover the near-final results and recommendations of a research project on Climate Change Adaptation of Urban Stormwater Infrastructure. The objectives of the project involve predicting future climate impacted design rainfall events and optimizing the cost-effectiveness of adaptations to stormwater infrastructure. To optimize the cost-effectiveness of stormwater infrastructure adaptations, the U.S. EPA’s SWMM software was used to model stormwater infrastructure in existing Minnesota watersheds under past, current and predicted future design storms (TP-40, Atlas 14, and several Global Climate Change model predictions). Various adaptation strategies were incorporated into the model for comparison: upsizing storm sewer pipes, adding wet ponds, retrofitting existing stormwater ponds to be “smart” ponds, adding rain gardens, and others. In addition to flood mitigation effectiveness, the project team also considered the relative cost of the adaptation strategies so stormwater managers can make informed decisions about how to redesign stormwater infrastructure for future rain events.

2:35–2:45 – TBD

Moderator: Lorin Hatch
Co-moderator: Greg Wilson

1:15–1:35 – 1062: Geochemical Augmentation with Alumina for Phosphorus Attenuation and Cyanobacteria Bloom Suppression in Lakes and Reservoirs: Summary of Project Results in Five Basins

David Austin, Roger Scharf, Jacobs

Geochemical augmentation with alumina enriches basins with hydrous aluminum (Al) oxide complexes in solution to scavenge phosphate from water and sequester it in sediments. The dosing protocol maintains basin total Al concentrations below the US EPA (2018) chronic toxicity threshold as determined by the US EPA model from inputs of basin pH, dissolved organic carbon, and total hardness.

Project data for alumina dosing (2015-2021) include a stormwater-fed urban lake (Kansas), a river reservoir (South Carolina), and three reuse reservoirs (Georgia). These projects inject alumina into bubble plumes at the basin bottom. Results for all basins are similar, lowering total phosphorus (TP) to the 10 to 60 µg/L range from initial concentrations as high as 250 µg/L at a rate near 1 µg/L/day. Concentrations of total Al remained well below chronic toxicity thresholds despite continual dosing. Additionally, project data demonstrate that geochemical augmentation with alumina suppresses cyanobacteria.

There is a Minnesota origin of geochemical augmentation. Saint Paul Regional Water Services has successfully used geochemical augmentation with ferric iron to lower TP for over three decades in Pleasant Lake and Vadnais Lake. Aeration or oxygenation keeps iron in an oxidized (ferric) state that binds phosphate in sediments. A stormwater pond in Shorewood has used geochemical augmentation with alum since 1997, consistently achieving pond TP near 40 µg/L. Alumina is redox insensitive and does not need to be paired with aeration or oxygenation to scavenge phosphate from water and permanently sequester it in sediments.

Geochemical augmentation with alumina is a powerful, low cost, and ecologically safe engineering method to control eutrophication in-basin. These basins can be stormwater ponds, lakes, or reservoirs. Evidence from projects across the United States unequivocally demonstrate efficacy. This presentation will describe the basics of how to do it and discuss supporting data.

1:35–1:55 – 1063: Sediment Core Collection Optimization for Internal Loading Management

Anne Wilkinson, Katie Kemmit, Conor Dougherty, Dendy Lofton, Stantec, Inc

Lake sediment chemistry has long been viewed as a critical component of nutrient cycling in lakes, in particular because of its relationship to internal phosphorus loading. Sediment cores are routinely collected for sediment physical and chemical characteristics from lakes as a component to internal loading studies. This presentation will highlight the importance and relevance of commonly collected sediment parameters for internal loading management. Another component of sediment core analysis for internal loading management, is the vertical sectioning of the cores, commonly every 2 cm, for chemical analysis. The sectioning of these cores can be costly and increases the turnaround time for results. Reducing the number of sediment core sections can save time and project cost without compromising the accuracy of the prescribed management dose. Stantec has collected sediment cores from over 100 lakes across the state of Minnesota for internal loading feasibility studies. Based on our sediment core database, we have identified trends in sediment core depth profiles to direct sediment core collection optimization and strategies. We will present strategies for the optimal core sectioning and the cost-benefit for internal loading management.

1:55–2:15 – 1064: Internal Phosphorus Loading in Lakes: What Is It and How Do We Manage It?

Dendy Lofton, Stantec

Phosphorus (P) loads to lakes are characterized by watershed (external) sources and within-lake (internal) sources. Decades of excess external P loads often leads to accumulation and burial within lake sediments, which can then be recycled among biological and physical components of the lake ecosystem. In cases where internal loading is a large portion of the total load, that source of P can sustain algal growth and poor water quality conditions even if external loads are reduced significantly. Consequently, internal loads need to be managed along with watershed load reduction actions to improve water quality. There are four primary pathways of internal P loading in lakes: diffusive flux, sediment resuspension, bioturbation and macrophyte senescence. Of those, diffusive flux of P typically comprises the largest proportion although the other pathways are more difficult to quantify. Multiple biogeochemical and geochemical factors regulate diffusive P flux including organic matter quantity and quality, hypolimnetic and sediment oxygen demand, and sediment mineral content among other processes. A deep understanding of these factors is critically important for determining whether sediment phosphorus inactivation using alum or other chemicals is an appropriate lake management technique. Using recent case studies, this presentation will describe the basics of sediment P chemistry and data requirements for calculation of an alum or Phoslock® dose, two chemicals commonly to lakes for mitigation of sediment P diffusion.

2:15–2:35 – 1065: The Role of Aluminum Sulfate (Alum) Treatments in the Restoration of Lake Riley, Minnesota

Joseph Bischoff, Barr Engineering Co.; Josh Maxwell, Terry Jeffrey, Riley Purgatory Bluff Creek Watershed District; William James, University of Wisconsin Stout

Lake Riley is a 297-acre recreational lake in the southwest suburbs of Minneapolis. The lake historically demonstrated poor water quality with nuisance algae blooms and poor water clarity. Although Lake Riley is a deep lake (maximum depth >49 feet), there were concerns regarding the impacts of common carp in the chain of lakes, existing populations of Curly-leaf pondweed and Eurasian watermilfoil, and establishment of a zebra mussel population. Since 2016, the Riley Purgatory Bluff Creek Watershed District (RPBCWD) has focused restoration efforts on the chain of lakes including carp control, efforts to reduce Curly-leaf pondweed, and nutrient management in the watershed and lake sediments. Following carp and Curly-leaf pondweed control, the final step in the restoration of the lake was an alum treatment to control sediment P release. However, there remained some concerns regarding the use of alum due to its large watershed and continued need to reduce watershed nutrient loading. Because of the long timeframe needed to implement watershed practices, Lake Riley was treated with alum in May 2016 and June 2020 to improve water quality while work continues in the watershed and upstream lakes. Anaerobic sediment P release was reduced by 83% between 2016 and 2021 resulting in summer average chlorophyll-a concentrations consistently below 10 µg/L and Secchi depths exceeding 15 feet. Aluminum bound P (Al-P) increased significantly following the second alum treatment suggesting future treatments may be more effective at converting mobile P to Al-P thereby reducing the cost of future alum treatments. While the water quality improvements were a success, continued tracking of the alum treatment will continue while watershed and upstream lake improvements continue. The success of the Lake Riley restoration demonstrates that significant improvements in water quality can be achieved and maintained while continued watershed and upstream lake nutrient reductions are pursued.

2:35–2:45 – TBD

Moderator: Jeffrey Peterson
Co-moderator: Will Bartsch

Growing Prospects for Winter Annual Crops in the Upper Midwest

Axel Garcia y Garcia, Grace Wilson, Natalie Hunt, Jeffrey Strock, Amit Pradhananga, William Lazarus, Colin Cureton, University of Minnesota; Brent Dalzell, Lucia Levers, USDA-Agricultural Research Service; Margaret Wagner, Jeffrey Berg, Minnesota Department of Agriculture; Anne Schwagerl, Minnesota Farmers Union

This session will discuss the latest on the prospects for placing winter annual crops on the Minnesota landscape. Speakers will share recent research on the agronomics and environmental impacts of winter crops, new data on the economic and social barriers to their adoption, and emerging developments in markets for winter oilseeds. A panel of industry, government, and scientific leaders will discuss the prospects for accelerated change in the coming years.

Moderator: Kari Benjamin
Co-moderator: John Bilotta

3:15–3:35 – 1032: Stormwater Pond Management Pilot Study

Jesse Carlson, Connor Johnson, City of Savage; Bill Alms, WSB

Communities are tasked with managing their constructed stormwater ponds so they can function at their highest potential. Ponds were originally constructed based on the critical design principles (Depth, Length-Width Ratio, Volume) that aimed to maximize the treatment effectiveness. We have learned that stormwater ponds have taken on a life of their own and act more like a natural system, and many ponds that are decades old have fallen out of balance due to a lack of oxygen, healthy aquatic plant life, excess organic matter accumulation and nutrient cycling. The City of Savage has been collecting water quality data for 7 stormwater ponds since 2018-2019. Most of the ponds have shown depleted dissolved oxygen levels and elevated phosphorus concentrations. The city determined that additional measures are needed to help improve the water quality and maximize the life cycle of the constructed ponds that they manage. This led to a pilot study starting in the summer of 2021, which investigates alternative treatments that include alum dosing, biological microorganisms, and aeration. The city has been doing water quality testing of these ponds both before and after treatment and will share the results of that work during the presentation.

3:35–3:55 – 1047: Minneapolis Pond Survey, Maintenance Assessment, and Internal Loading Analysis

Nico Cantarero, Stantec; Shahram Missaghi, City of Minneapolis

The City of Minneapolis conducted a stormwater pond assessment to identify maintenance actions as part of its Stormwater Maintenance Program. This assessment provides the City with the information to better understand the current condition of its ponds and plan accordingly for recommended maintenance actions. This also provided an opportunity for the City to gather missing pond survey data, assess the ponds pollutant removal performance, conduct a detailed assessment of internal phosphorus release, and provide recommendations for operational practices to maximize their effectiveness. The City also partnered with the MPRB to coordinate additional water quality monitoring within the ponds.

3:55–4:15 – 1049: Evaluation of Wet Detention Pond Performance and Application of the General Lake Model

Caitlin Lulay, Anthony Parolari, Brooke Mayer, Walter McDonald, Marquette University

Urbanization degrades surface water quality through increased nutrient accumulation and transport in stormwater runoff. Wet detention ponds (WDP) are a means of mitigating non-point source pollutants such as phosphorus (P) through sediment settling and biological uptake. WDPs serve as a nutrient sink and potentially as a nutrient source due to P release back into the water column through algal decay and sediment resuspension. Existing models used for design and regulatory evaluation do not consider algal P dynamics or sediment resuspension. These gaps may explain widespread WDP effluent P concentrations that exceed water quality standards. To better understand WDP P dynamics toward improved design and analysis models, we studied the temporal variation and biogeochemical controls of P in 2 WDPs over a 4-month period (July – Oct 2021) that included eleven storm events. DO, conductivity, temperature, and water level were recorded as well as pH, conductivity, temperature, and ORP profiles. P and total suspended solids were measured in bi-weekly grab samples and storm influent/effluent. Pond P was consistent over time, while influent concentrations and loads were elevated in the early summer and fall. Effluent concentrations and loads were lower relative to influent for most storms, except those in October when effluent loads were higher. Elevated effluent loads were associated with higher TSS and particulate P, indicating either washout of algal biomass or resuspension of pond sediments. These results indicate marked seasonal variability in the P removal efficiency of SW ponds. Using the General Lake Model, a sensitivity analysis was performed which showed that P removal was most sensitive to pond volume and maximum sediment-P flux. These findings support the value placed on dredging as a maintenance mechanism of WDPs. This knowledge is important for improving WDP design and maintenance strategies that optimize nutrient removal to mitigate water quality degradation.

4:15–4:35 – 1058: Pond Treatment with Spent Lime to Control Sediment Phosphorus Release

Greg Wilson, Barr Engineering Co.

Sedimentation ponds that accumulate particles and phosphorus from stormwater runoff are a standard, widely applied best management practice. However, aging ponds have potential to release more phosphorus than is captured during summer months. Recent monitoring efforts from the Twin Cities Metro area have confirmed that sediment phosphorus release is an increasingly significant concern for many stormwater ponds that are relied upon for meeting Total Maximum Daily Load requirements for phosphorus wasteload allocations. In addition, there is also significant interest in spent lime treatment as an option to address internal phosphorus load in lakes. Dredging is an expensive option to improve pond performance, while areal applications of alum and iron can control phosphorus release but incur raw material production costs. Using MSRC/CWF funds and in-kind contributions from RWMWD, VLAWMO, SPRWS and City of White Bear Lake, Barr studied spent lime applications to ponds to reduce sediment phosphorus release. SPRWS currently spends one million dollars a year to transport spent lime to agricultural producers, confirming that there is significant financial incentive for utilities that use lime for water softening to find cheaper alternatives for beneficial reuse. Results of this study, which includes both laboratory and field-scale components intended to validate the efficacy of spent lime applications to control sediment phosphorus release, will be presented. The laboratory component included spent lime addition to pond sediment cores to evaluate pH effects and optimize spent lime dosing, while the field component included spent lime addition to two ponds and post-treatment monitoring to evaluate the water quality benefits. This talk will also address proof-of-concept issues, including cost-effective methods for aerial application, permit considerations and cost-benefit comparisons with other control options such as dredging, alum treatment and the application of iron filings.

4:35–4:45 – TBD

Moderator: Ann Banitt
Co-Moderator: Kimberly Hill

3:15–3:35 – 1033: Wood Lake Lift Station—From Feasibility to Construction

Bill Alms, Kendra Fallon, WSB; Olivia Wycklendt, City of Richfield

Wood Lake in the City of Richfield has routinely experienced high water levels in the recent past which inundates and has washed out trails around Wood Lake in the Richfield Nature Center. The City commissioned a feasibility study to analyze options for addressing the high water levels of Wood Lake. The proposed improvements analyzed and recommended needed to address the following:

• Reduce and/or regulate the water levels in the lake
• Be easy to implement by City Public Works Staff
• Meet the goals of several stakeholders including the City of Richfield engineering and nature center staff, MnDOT and private utility companies

Several alternatives were analyzed in the feasibility study and the selected alternative was to increase the pumping capacity of the existing lift station from Wood Lake to provide the ability to draw down Wood Lake quicker than the lift station currently allowed. As the lift station discharges into MnDOT trunk storm sewer, design and construction of the improvements required extensive coordination and permitting with MnDOT. There were multiple challenges during construction that were overcome including access coordination with commercial property owners adjacent to the construction site, construction timeline adjustments due to utility company coordination, and installing the sensor and associated electrical work for switching the additional pumps on and off based on available capacity within the MnDOT trunk sewer. The improvements were constructed in the Summer of 2021 and have been utilized and monitored from that time on.

3:35–3:55 – 1041: Parallel Floodplains: A regional public-private partnership

Mat Cox, Kimley-Horn and Associates

What do you get when you mix 3 different developers with 2 new public roadway segments, 1 potential future roadway expansion and extension, a creek crossing of a designated trout stream, 2 creek crossings of a delineated FEMA floodplain (1 with floodway) and a combination of both public and private wetland impacts? An opportunity to evaluate and design the separate projects in a more thoughtful manner and result in a more effective and efficient design that meets the needs of the developers while addressing the water resources standards of the City of Lakeville and paves the way for the future roadway extension to implemented without significant changes to the overall system. This presentation will discuss how the projects that started down independent paths came together and how the partnership between the public and private owners collaborated to develop a system that not only met the requirements but went above-and-beyond in terms of water quality treatment. The nature of the independent projects required analysis of several different phasing approaches depending on when each of the parts would be constructed. The presentation will also discuss floodplain modeling efforts to result in no-rise certifications for the crossing of both creeks and the development of detailed XP-SWMM site modeling for the separate projects within the larger regional XP-SWMM model.

3:55–4:15 – 1044: Small Site Permitting for Local Flood Issues

Zuleyka Marquez, City of Edina

The City of Edina undertook a stormwater modelling effort that allowed for visualization of local and regional flooding issues throughout the city. These GIS tools are published internally and externally. Internally, they are used to inform stormwater and floodplain development policy decisions and are critical for permit review. Externally, existing and prospective residents and builders/developers can assess the flood risk in the neighborhood. Model updates are continuous and can be informed by ongoing redevelopment. Mapping has allowed for more consistent and thorough permitting review and inspections. Additionally, as we think through these flooding and drainage during permit review, we have opportunities to identify future solutions, such as City projects and revised standards.

4:15–4:35 – 1042: Everest Lane Stream Stabilization Project

Kendra Fallon, Jake Newhall, WSB; Derek Asche, City of Maple Grove

The City of Maple Grove’s Everest Lane Stream Stabilization Project is located directly upstream of Elm Creek which is currently listed as impaired by the MPCA. The projects goals were to:

• Stabilize roughly 800 linear feet of a ravine showing signs of heavy erosion and channelization to reduce sediment loading to Elm Creek and reduce sloughing safety concerns to adjacent properties
• Provide energy dissipation within the ravine while maximizing bioengineering techniques to maintain the natural drainage way
• Replace failed infrastructure with long term solutions to reduce future maintenance for the City

A combination of regrading, hard armoring, and bioengineering were used to help stabilize the eroded side slopes of the channel while ditch checks and plunge pools were strategically placed to maximize energy dissipation within the channel. A SMS SRH-2D hydraulic model was created to assist in the design and help determine the best locations for different stabilization techniques based on anticipated velocities and shear stresses within the channel.

Sustainability was considered throughout the project from design to construction. Some of the large trees which had either already fallen into the ravine or were removed during construction to help ground level revegetation efforts were used for onsite stabilization. Tree trunks were anchored into the toe of the slope as a form of toe stabilization or were used in combination with riprap to form some of the ditch checks. The grading, bank stabilization, and infrastructure construction has been completed and vegetation establishment efforts for the Everest Lane Project are still ongoing. Final restoration is anticipated to be completed Spring 2022.

4:35–4:45 – TBD

Moderator: Tracy Fallon
Co-moderator: Joel Larson

3:15–3:35 – 1031: A Field Study of Maximum Wave Height, Total Wave Energy, and Maximum Wave Power Produced by Four Recreational Boats on a Freshwater Lake

Jeffrey Marr, Andrew Riesgraf, William Herb, Matthew Lueker, Jessica Kozarek, St. Anthony Falls Laboratory University of Minnesota; Kimberly Hill, Department of Civil, Environmental, and Geo-Engineering, University of Minnesota

Recreational boating on inland lakes is an increasingly popular activity that continues to evolve with the introduction of new types of boats and tow sports. The emergence of wakesurf boats and the sport of wakesurfing introduces a completely new mode of boat operation, where the goal is to produce a large wake that is suitable to surf on. There is growing concern over boat-generated waves and their environmental impacts to lakes and rivers. The research discussed here was motivated by a need to better understand the characteristics of wake waves produced by common recreational boats. In this talk we present results from a recent field-based study that characterized the size, energy and power of the wake waves generated by four types of recreational boats. Two of the boats were more traditional recreational boats that are commonly used for tow sports like tubing and waterskiing, and the other two boats were wakesurf boats specifically designed for the sport of wakesurfing. Five wave monitoring stations were deployed on Lake Independence (Maple Plain, Minnesota) at various distances from the shoreline. Testing involved operating each boat at four distances from the shoreline (225 ft, 325 ft, 425 ft, and 625 ft) under various conditions (e.g., speed, ballast weight, trim setting, etc.). The results show clear differences in the wake wave characteristics between the more traditional boats and wakesurf boats. Notably, when operating in surf conditions wakesurf boats produce wake waves that are substantially larger and contain more energy and power than traditional recreational boats. The research findings can be used to inform boat operational distances necessary to attenuate wake wave heights, energies, and powers to levels deemed acceptable. Moreover, the findings can help us begin to understand the possible impacts of recreation boating activities on shorelines and lake bottoms.

3:35–3:55 – 1059: Effectiveness and costs of aquatic invasive species spread prevention in Minnesota.

Nichole Angell, Nicholas Phelps, Valerie Brady, Amy Kinsley, Josh Dumke, University of Minnesota; Tim Campbell, Wisconsin Sea Grant; Reuben Keller, Loyola University Chicago; Adam Doll, Minnesota Department of Natural Resources

Efforts to prevent the spread of aquatic invasive species (AIS) have been widely implemented on local and regional scales to mitigate the economic and environmental harm associated with these organisms. Watercraft inspection and decontamination, along with boater education and outreach, are popular prevention strategies; however, few studies have investigated the effectiveness and cost effectiveness of these approaches. In this study, we aim to fill these knowledge gaps to inform management decision-making by providing more nuanced information about watercraft inspection effectiveness and by using program cost data to estimate prevention benefits for specific monetary investments. Effectiveness of AIS prevention strategies will be estimated by evaluating boaters and watercraft inspectors during experimentally controlled boat inspections. During these inspections we will realistically stage a boat with fresh macrophytes and dead or preserved AIS. Participants will be asked to inspect and remove any items as they would after a typical outing on a lake. Both the types of organisms and the amount removed from the boat will be used to estimate effectiveness for any one inspection. We pilot tested these methods in the Fall of 2021. Preliminary results suggest that boating frequency is positively correlated with effective removal by boaters and differences likely exist between types of AIS. In addition, costs of all evaluated prevention strategies will be determined by reviewing existing literature and interviews with AIS managers. This work is ongoing and preliminary results will be presented. Ultimately, these data will be incorporated into the online decision support tool, AIS Explorer (www.aisexplorer.umn.edu) to guide future management decisions.

3:55–4:15 – 1060: Spatial Patterns and Environmental Drivers of Horizontal, Diel, and Seasonal Distribution of the Invasive Aooplankton Bythotrephes in a Minnesota Reservoir

Megan Corum, Donn Branstrator, University of Minnesota Duluth

Understanding the distribution of invasive zooplankton like Bythotrephes cederstroemii is essential for accurate population estimates. Island Lake Reservoir (Duluth, MN, USA) is a tannin-stained lake that supports a persistent population of Bythotrephes despite tannin-stained waters limiting visibility. In order to describe the horizontal, diel, and seasonal distributions of Bythotrephes, a nearshore to offshore transect was sampled at four depth sites (2 m, 8 m, 12 m, and 16 m). Samples were collected monthly during the day and again the same night from June to October. Bythotrephes density and biomass during the nighttime exceeded the daytime at all sites. The intermediate sites (8 m and 12 m) supported the most biomass across all months. Contrary to expectations, Bythotrephes density was highest at the 2 m site on several sampling dates. These results are interpreted alongside simultaneous measurements of prey abundance, temperature, and dissolved oxygen. These results begin to fill gaps surrounding the distribution of the Bythotrephes population on different scales.

4:15–4:35 – 1061: Boot, Root, & Boogie (Carp Booted, Plants Rooted, Staff Boogied)

Jeff Anderson, Shauna Capron, Elizabeth Froden, Prior Lake-Spring Lake Watershed District

Carp Removal as an Approach to Increase Submerged Aquatic Vegetation

The impaired waters of Spring and Upper Prior Lakes in the Prior Lake-Spring Lake Watershed District were identified in TMDL reports as having excess internal nutrient loading, with common carp activities as one of its main contributors. Since 2014, with support from MPCA , DNR, and BWSR grants, PLSLWD employed novel approaches to remove carp biomass from these lakes that have led to significant improvements in water quality. The District created an Integrated Pest Management Plan (IPM Plan) for Common Carp. The IPM Plan provides long-term guidance for data collection that informs decision making and implementation activities, along with guidance for monitoring of ecological changes within Spring and Upper Prior Lakes.

The overarching goal of the IPM Plan is to improve water quality by reducing total phosphorus (TP) and chlorophyll-a (Chl-A) concentrations and increasing Secchi depth to meet site specific standards. Between the years of 2019 and 2021, carp biomass was reduced in Spring Lake by 19,154 pounds, and internal TP loads were reduced by 198 pounds/year. In Upper Prior Lake, 39,367 pounds of carp were removed and internal TP loads were reduced by 499 pounds/year. Given the reduction in carp biomass and improved water quality, the District anticipated, and experienced, an increase in submerged aquatic vegetation. Point intercept surveys and vegetation density mapping have shown increases for nine new species in Spring Lake. Submerged aquatic vegetation percent area coverage increased from 18 percent to 60 percent in Spring Lake and from 11 percent to 52 percent in Upper Prior Lake.

This presentation will share pre-implementation conditions, carp reduction methodologies, and post-implementation water quality and aquatic vegetation findings.

4:35–4:45 – TBD

Moderator: Jeffrey Peterson
Co-moderator: Will Bartsch

Growing Prospects for Winter Annual Crops in the Upper Midwest

Axel Garcia y Garcia, Grace Wilson, Natalie Hunt, Jeffrey Strock, Amit Pradhananga, William Lazarus, Colin Cureton, University of Minnesota; Brent Dalzell, Lucia Levers, USDA-Agricultural Research Service; Margaret Wagner, Jeffrey Berg, Minnesota Department of Agriculture; Anne Schwagerl, Minnesota Farmers Union

This session will discuss the latest on the prospects for placing winter annual crops on the Minnesota landscape. Speakers will share recent research on the agronomics and environmental impacts of winter crops, new data on the economic and social barriers to their adoption, and emerging developments in markets for winter oilseeds. A panel of industry, government, and scientific leaders will discuss the prospects for accelerated change in the coming years.