Environment

MPCA says polluted runoff contributed to fish kill in Minnesota trout stream

Dead fish along a creek
Dead fish are seen along Rush Creek near Lewiston, Minn., on July 27. State agencies said a fish kill along the creek left an estimated 2,500 fish dead.
Photo by Carl Berberich, courtesy of Minnesota Trout Unlimited

State regulators say polluted runoff likely contributed to a fish kill in a southeast Minnesota trout stream last summer.

About 2,500 dead fish were discovered in late July in Rush Creek, near Lewiston in Winona County. Most were brown trout.

The Minnesota Pollution Control Agency and other agencies investigating the fish kill didn’t find a direct discharge of pollutants into Rush Creek.

But in an update Thursday they concluded that manure and pesticides applied to land upstream shortly before a rainstorm, along with low-flow conditions in the creek, are likely to blame.

“There was no single cause or discharge identified. There was a major runoff event upstream of this location and likely significant runoff from a lot of different land uses, a lot of different fields,” said Justin Watkins, watershed unit supervisor for the MPCA’s southeast region.

Watkins said landowners should be aware of weather conditions when they apply manure or chemicals.

“There’s no way to say that fish kills can completely be eliminated. But a risk management approach really can help minimize them or reduce the frequency,” Watkins said.

The MPCA cited two facilities in Lewiston for incomplete recordkeeping, and applying manure too close to a sinkhole and a special protection area.

John Lenczewski, executive director of Minnesota Trout Unlimited, spoke with MPR News last summer and described Rush Creek as a “top-notch trout stream that draws people from not just around the state but from outside the state.”

In the wake of previous fish kills in the region, he said at the time that there was frustration that it had happened again — and a desire to find ways to prevent future fish kills.