Sophia Koch graduated in 2018 from UW-River Falls with a degree in journalism and a minor in biology, and she now works as a freelance science writer. She’s loved exploring the St. Croix River by kayak ever since she interned with the St. Croix River Association in 2017.

In an ongoing effort to curb phosphorus pollution in Lake St. Croix, organizations from all levels of government in Wisconsin and Minnesota are working together to implement watershed management practices throughout the St. Croix River basin. 

The St. Croix River is widely considered a valuable resource to both Minnesota and Wisconsin. The river is known as one of the most pristine in the Midwest, with overall good water quality that supports a variety of wild species. 

This pristine water quality, however, does not come without effort.

Located in the lower 25 miles of the St. Croix Basin, Lake St. Croix was categorized by Minnesota and Wisconsin as “impaired” by the Environmental Protection Agency in 2008 due to an overabundance of phosphorus nutrients causing excessive algae blooms. 

In response, the Minnesota Pollution Control Agency, the Wisconsin Department of Natural Resources, and the St. Croix Basin Team collaborated to create a Total Maximum Daily Load (TMDL) report, outlining the scope of the problem. Once that was approved by the EPA, the St. Croix Basin Partners went on to write an implementation plan, outlining the restoration goals.

“It creates a really good launching pad to do the work,” said Monica Zachay, Land and Water Program Director for the St. Croix River Association. “The TMDL and implementation plan were really a great tool for us to say, ‘Okay, we have this plan. Now give us the funding so we can do the work.’” 

The TMDL and Implementation Plan set some lofty goals. According to the TMDL, in 2008, approximately 460 tons of phosphorus were entering Lake St. Croix each year. The goal is to reduce that number back to the 1940 level of 360 tons/year (which is where St. Croix 360 gets its name). This equates to an overall needed phosphorus load reduction of 27 percent.

By 2020, the St. Croix Basin Partners had hoped to be close: 20 percent reduction of phosphorus loading. 

It’s a big project, however; it requires the coordination of dozens of federal, state, and local organizations across a 160-mile river whose basin encompassses 7,760 square miles of land. Tracking progress is difficult since each organization has a different method for quantifying their data. Phosphorus also leaches into watersheds from a wide variety of sources; some can be easily regulated because they have a specific “point” source like wastewater plants or factories. Others are more difficult because they’re “non-point,” meaning they come from the general landscape and can’t be traced to one source.

“It’s very challenging for it to happen within the timeframe that the TMDL is allocating,” said Jay Riggs, manager of the Washington County Conservation District. “It’s going to take a lot of time and a lot of work to get those load reductions.”

The 20 percent reduction goal will probably not be met by 2020, but the St. Croix Basin Partners have been making a lot of progress nonetheless, with numerous projects implemented to reduce runoff and the phosphorus it carries from reaching Lake St. Croix.

Projects include rain gardens, water and sediment control basins, vegetated swales, gully stabilizations, stormwater pond retrofits, and cover crops. Between Wisconsin and Minnesota, there have been over 2,000 such projects installed, with funding coming from sources like Minnesota’s Clean Water Fund, the United States Geological Survey, and the Natural Resources Conservation Service. 

“We’re seeing tremendous improvements in water quality, especially in the prioritized watersheds we’re working on,” said Craig Mell, District Administrator of the Chisago Water Conservation District. “Landowners have been very receptive…and the biggest thing–we’ve secured a lot of state and federal and local funding to get the projects completed.”

Moving forward, there will always be more projects to be done and more grants to apply for. However, through the new “One Watershed, One Plan” initiative, the Minnesota Board of Water and Soil Resources aims to unite local water planning, creating a more coordinated system for writing implementation plans by 2025.

“We’re on a good path to becoming more successful at achieving those load reduction goals,” said Jay Riggs from the Washington County Conservation District. “It’s not just more of the same–I think we’re going to have better coordination. I think we’re going to do a better job at making sure we’re getting the biggest bang for the buck.”

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