What you need to know about Minnesota's un-swimmable streams and lakes


The Minnesota Pollution Control Agency reported this week that a study found most of the streams and lakes in the southwestern part of the state are so polluted they are unsuitable for swimming or fishing.

The agency examined 93 streams and all of the lakes in the Minnesota portion of the Missouri River basin, and found zero lakes and only three streams had a high enough water quality to sustain aquatic life.

Thursday, the MPCA's surface water monitoring manager Glenn Skuta provided more details on the report.

What is causing the pollution in SW Minnesota?

The study found that sediment, nitrates, and bacteria are polluting the rivers and lakes.

The MPCA will conduct more tests to determine what the individual causes are, but the main culprit appears to be the intensive farming on the land, which is causing nitrates from fertilizers to run-off into the waterways.

Skuta said that certain pollutants in the southwest, such as phosphorous and ammonia, have actually decreased in recent years, but officials have noticed an increase in nitrates in the water.

The U.S. Geological Survey notes that excess nitrates can overstimulate aquatic plant and algae growth, clogging up streams or lakes and reducing oxygen levels in the water, which can adversely impact fish populations.

Is this a recent problem?

No, this is a historic problem in the southwest corner of the state, where much of the land is used for agriculture.

The MPCA also referred to the "great disturbances" of the landscape in southwestern Minnesota in recent centuries, as wetlands and prairie were gradually replaced in the drive for more farmland.

What can be done about it?

There's not much the MPCA can do through enforcement to make farmers change their ways. The agency points out that agricultural companies are exempt from many of the laws that would give the MPCA more control over how they conduct their business.

Instead, officials will look to collaborate with landowners to come up with ways to prevent further pollution caused by surface run-off.

Another idea that's been welcomed by the MPCA is Gov. Mark Dayton's proposal in January to create "buffer zones" between agricultural land and waterways to reduce contamination and improve conditions for local wildlife, as reported by the Star Tribune.

This is designed to reduce the chemical run-off issue as well as erosion, and limit the ability of cattle to access and contaminate streams and rivers.

What's the impact on the public?

The polluted water contains bacteria, so swimming, fishing or drinking water from these lakes carries health risks. High levels of nitrates can pose dangers to young infants in particular.

One of the lakes in the southwest was found to contain blue green algae, which can prove toxic to dogs, livestock and other animals, and can cause skin irritation, nausea and eye, nose and throat problems in humans.

There are also the aesthetic problems it causes as well, as waters get clogged up with dense aquatic plants and covered with algae, rendering them all but unusable for recreational uses like swimming, kayaking and fishing.

How are the rest of Minnesota's waterways?

The MPCA is conducting similar reports for all 81 of Minnesota's "watersheds," a list which you can find here, that it studies on a 10-year rotation.

It is expected to have completed its latest round of studies by 2019, but has said it will publish a mid-term report some time this spring updating people on the general condition of the state's waters.

Skuta said that in general Minnesota's lake, river and stream quality is at its best in the northeastern part of the state – where there are more forests and parks and fewer farms – and deteriorates the further southwest you move as the use of land changes and becomes more agricultural.

The MPCA provides a snapshot of how the current quality of lakes, rivers, streams and groundwaters are in Minnesota on its website.

What's next?

The study into what is causing the issues in the southwest could take one or two years and the findings will go into the organization's strategy to set about cleaning up lakes and streams.

Either way, it's going to take a long time, with Skuta saying there's no "quick fix" to solve the problem. The MPCA will need help from several sources, especially the farming industry, if it's to improve water quality in the future.

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