A stretch of St. Croix River from Taylors Falls to Stillwater was recently listed under the Minnesota Pollution Control Agency’s list of impaired waters. The agency is required to update its list every two years and recently completed its list for 2020.

“By means of water quality standards, we have goals to protect the things we use the water for,” MPCA Impaired Waters List coordinator Miranda Nichols said. “In the case of the St. Croix, there’s too much phosphorus, and it’s feeding algae that’s detrimental for fish and bugs.”

The listing didn’t surprise those at the agency. Lake St. Croix, which is south of Bayport, has been on the list of impaired waters since 2008 due to high phosphorus levels.

“We’ve known for a long time there’s phosphorous [in the St. Croix],” Nichols said.

Testing for phosphorus is standard for the agency, but in 2015, the MPCA updated its standards for testing for water quality and spent the next three years collecting data across the state. The agency was able to compile the data this year and found through its additional data what was long suspected.

“Obviously, we were incredibly disappointed that it was listed,” said Deb Ryun, executive director of the St. Croix River Association. “I think we should take it as a serious threat for the long-term health and viability for this river. It was set aside [by the national Wild and Scenic Rivers Act, established in 1968]. It’s an incredibly special place that has been threatened before and continues to be threatened, and I think we need to take this listing very serious.”

How it got there

There are a variety of ways in which phosphorus finds its way into the river, but one of the biggest factors is the nutrients and other chemicals in soil that are picked up in water runoff.

“It’s coming from the land. Anytime you think of water hitting bare earth, that is washing down dirt and nutrients. That’s an issue,” Nichols said.

While some may suspect that’s due to rural or farming areas, Nichols and Ryun both stressed that both urban development and rural agricultural areas have affected the water.

“The St. Croix watershed has some big urban areas, so that’s also contributing, including anything that goes down a storm drain,” Nichols said. “Because the St. Croix River watershed is so big, that phosphorus is coming from all sorts of different places. It’s not just sitting there in the river, it’s being brought in from tiny streams and emptying into the St. Croix.”

Minnesota began putting restrictions on the use of fertilizers with phosphorus in 2004, but Nichols said that soil itself can carry phosphorus. While staying away from the use of materials with phosphorus helps, there are many other ways for phosphorus to get into the river, from street gutters, sewer pipes, and animal and human waste.

“There are a number of ways [it gets there], but primarily it’s through organic waste, human and pet waste, or lawn clippings and leaves,” Ryun said.

Nichols added that the high levels of phosphorus can lead to an increase in large algae blooms, and the unhealthy water quality also affects other natural plant and water species.

“If you don’t want green water, we need to keep the phosphorus levels down,” Ryun said.

What’s being done

While the listing indicates a serious threat, Nichols says that the MCPA has seen success in dealing with high levels of phosphorus in other areas in the state, including in the northern part of the St. Croix River.

“There is hope,” Nichols said. “You go upstream, and it’s looking pretty good. … In Minnesota we’re pretty lucky, more lucky than most states, in that we have funds set aside to help tackle these problems. The clean water fund will be used to pay for efforts to reduce stream erosion and runoff.”

The Metropolitan Council has collected decades of research on phosphorus data and has shown a steady decrease in levels in previously listed waters due to upgrades and other initiatives, like upgrades to wastewater treatment plants and work with area residents to combat runoff and other concerns. In addition, Nichols said, there are groups within Minnesota and interstate associations that are already working on addressing the issue.

“The impairment indicates the water’s all connected, and it signals that more needs to happen in order to bring those phosphorus levels down even more-so,” Nichols added.

The St. Croix River Association hasn’t made any specific directives or action plans yet but will be working with the MPCA as it moves forward with its goals and will also likely host a public forum in January.

In the meantime, Ryun listed some ways residents can help make an impact now, including the following:

• Protect storm drains. Don’t dump leaves, fertilizers, oils down any drains.

• Sweep and mow away from the street, so clippings and dirt don’t end up in the storm drains.

• Get phosphorus-free products, from lawn fertilizers to dish soaps.

• Pick up pet waste. “It can have a huge impact,” Ryun added.

Ryun stressed that the listing doesn’t change how people can enjoy or utilize the river, but she did add that everyone can help keep phosphorus levels down.

“Our takeaway from this is everybody has a part to play,” she said. “If you recreate here or you live here or have a business here or live on a tributary, we can work together.”

The MPCA will host a public meeting regarding the St. Croix’s listing on Dec. 19 at 1 p.m. at its office in St. Paul, located at 520 Lafayette Road N. For those who can’t attend the meeting, it will be broadcast online or via phone. To access the meeting, visit pca.state.mn.us/water/minnesotas-impaired-waters-list and scroll down to Metro: Dec. 19.

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