Drought cuts river pollution levels in Minn.by Mark Steil, Minnesota Public Radio
WORTHINGTON, Minn. — The rapid fall in river levels around the state has at least one benefit: Water pollution levels have also declined.
Abnormally dry to extreme drought conditions cover nearly the entire state, causing stream levels to fall sharply. In southern Minnesota, some smaller rivers have practically stopped flowing.
Minnesota Pollution Control Agency hydrologist Patrick Baskfield said the low flows have also cut the levels of some pollutants, like phosphorous, to almost undetectable levels.
"We're almost at that level in the Minnesota River right now," he said.
Levels are so low because there's very little polluted water coming into the streams, Baskfield said. "Agricultural runoff, urban runoff, those contributions decrease because we have a lack of overland flow," said Baskfield.
Baskfield said the lack of runoff also means the water in most rivers is clearer than during normal times, because less soil is washed into the streams.
Falling river levels sometimes are dangerous to fish populations because dissolved oxygen levels can fall. So far this year, there haven't been many drought-related fish kills in Minnesota.