2017 NIWR grant awardees showcase diversity of water research

by Minnesota Water Resources Center

A picture of the study area on the West Swan River in St. Louis County, Minnesota.
Study area on the West Swan River in St. Louis County, MN. Researchers with the
new WSC project add new turbidity measurements to ongoing flow and water
quality measurements and will be developing open source sensors in this northern
Minnesota stream with high dissolved organic material concentration.
(Photo credit: D. Karwan)

The U.S. Geological Survey-funded NIWR 2017 grant competition yielded three project awardees, announced earlier this year. Funding is available to researchers (pending Congressional budget action later this year) through the Minnesota Water Resource Center’s selection process, which chooses from submitted competent applied and peer reviewed research submissions each November. This year’s grants highlight methods to mitigate nitrogen and phosphorus from drain tile, open source monitoring of turbidity in surface water and test the efficacy of buffer strips in deterring the export of organic matter and the resulting algal blooms.

Investigation of a novel approach to mitigate nitrogen and phosphorus from tile drainage

PI Jeff Strock and a team of researchers from the University of Minnesota have designed a novel bioreactor which when installed in agricultural ditches, treats water from subsurface tile drains, removing nitrogen (N) and phosphorus (P) from the water leaving the farm fields. Unlike other bioreactors this new version removes both N and P, preventing nutrients from entering surface streams and rivers in the Midwest. “This project should lead to greater sustainability of agricultural production in Midwestern regions where corn and soybeans are produced,” said Strock.

Open-Source Turbidity Sensor to Monitor Suspended and Dissolved Matter in Surface Water

“Turbidity is the single most prevalent form of water pollution in Minnesota, but measurements of it are sparse in either space or time,” says Andrew Wickert (Department of Earth Sciences), lead PI on the project. Wickert and his co-PIs Diana Karwan (Department of Forest Resources) and Chad Sandell (Department of Earth Sciences) intend to develop a low-cost turbidity sensor that can differentiate between dissolved and suspended loads, help to quantify and mitigate land-use practices that lead to soil loss, and be easily deployed across Minnesota and beyond. Laboratory and field testing and deployment of this new sensor will guide its development, improve monitoring of post-logging erosion, and produce immediate data on water quality in agricultural southern Minnesota. This work will enable the construction of large networks of high-quality turbidity sensors and data loggers. Such networks will provide valuable information on erosion, land-use impacts, and water quality. The proposed initial deployment of these sensors will directly benefit Minnesota watershed data on sediment loads in logging and agricultural regions. These benefits can be summarized in terms of two main \deliverables", described below in Section 17: to (1) create a low-cost and open-source turbidity sensor that can differentiate between suspended and dissolved load and (2) perform high-frequency monitoring of turbidity in the Swan and Le Sueur River watersheds.

Assessing the role of buffer strips in nutrient and organic matter export and mitigation of harmful algal blooms

In 2015, Minnesota enacted a new law requiring the installation of vegetative buffer strips along the boundaries of all public waters and public drainage systems by 2018 to limit the transport of nutrients from the land into aquatic systems. PI James Cotner (Department of Ecology, Evolution and Behavior) hopes his project will inform the shift in land use practices that the implementation of the law will require. This project will also predict the effectiveness of buffer strips in controlling eutrophication in nearby streams and lakes. Eutrophication is a contributing factor in the formation of harmful algal blooms (HABs), which degrade water quality.

Cotner will study ten systems in agricultural regions of Minnesota, sampling lakes and inflow tributaries, measuring the effect of buffer strips on the export of organic matter downstream.

“Buffer strips are known to be effective traps for inorganic nutrients, but little is known about the composition and reactivity of organic matter that is transported through these zones. Our work will fill this knowledge gap, and show how planktonic communities are affected by buffer strips, evaluate the potential for effects on HABs, and describe potential feedbacks that could either enhance or limit the ability of buffer strips to lessen the impacts of eutrophication,” said Cotner.