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In the Land of 10,000 Lakes, (at least) 2,700 are too polluted for swimming

The Chain of Lakes in Minneapolis, which includes Brownie — recently delisted as a polluted lake.

The Chain of Lakes in Minneapolis, which includes Brownie — recently delisted as a polluted lake.

About 10 years ago, Minnesota voters elected to give the Minnesota Pollution Control Agency three-eighths of every cent on sales tax. It funded a massive state-wide tally of how just how polluted every lake, river, and stream is.

Turns out, many of Minnesota’s waters are in bad shape. The MPCA has only completed studies on about 40 percent of the state’s waters so far, and 2,693 are listed as being polluted to the point that people really shouldn’t be using them to boat or swim, much less fish or drink. This year, there were 300 additions to the list.

Glenn Skuta, MPCA’s watershed director, is clear: It’s not all doom and gloom. More of Minnesota’s waters are healthy than they are polluted, and pinpointing the causes of pollution is the first step in cleaning it up.

“We’re finding more impaired waters because we’re looking more,” Skuta says. “We didn’t have a lot of resources to do this work 10 years ago. Now we’re out there, we’re looking, and so we’re finding them. It’s not like all of a sudden all these waters are impaired that weren’t previously.”

In fact, 86 lakes and rivers were actually delisted this year, as communities of homeowners and farmers around the state rallied to scrub them. They include Lake Shaokotan in far southwestern Minnesota, Red Rock Lake in Eden Prairie, and Brownie Lake in Minneapolis.

“At the same time it is a lot of waters that we are adding, so it definitely does point out that we have a long way to go to be a better clean water state than we have been,” Skuta says. 

One classic culprit is the chloride that comes from road salt. Even though cities and the state transportation department have gotten better at using less salt over the years, it's one of those things that just doesn't evaporate or break down easily. Particularly in metro-area lakes, chloride has accumulated over time. 

In the rural, agriculture-heavy parts of southwestern Minnesota, nitrate and phosphorus runoff seems to be a growing problem. Manure and septic system leakage causes outbreaks of algae and scum, which can choke natural habitats and render lakes unusable.