A waterbody can be listed as impaired on the United States Environmental Protection Agency’s 303(d) impaired waters list if it does not meet the state’s water quality standards for a pollutant (Minnesota's impaired waters list | MPCA). Silver Creek was listed as impaired for acetochlor in 2016 after it was found to exceed the chronic Minnesota water quality standard in 2012 and 2014. Silver Creek, a tributary to Bevens Creek located at the western edge of the Twin Cities Metropolitan Area in Carver and Sibley County, is the only water body impaired for acetochlor in Minnesota at this time (Figure 5). A response plan to the Silver Creek impairment is being developed in collaboration with the Minnesota Pollution Control Agency (MPCA). Visit the MPCA's Total Maximum Daily Load (TMDL) program page for more information.
There have been two previous acetochlor impaired waters listings in Minnesota. In 2008, two south central Minnesota streams, Le Seuer River and Beauford Ditch were listed as impaired after acetochlor was detected above the state chronic water quality standard in 2001 for the Le Sueur River and 2005 for the Little Beauford Ditch. The Little Beauford Ditch is a tributary of the Le Sueur River and is located in Blue Earth County south of the city of Mankato. In cooperation with the Acetochlor Registration Partnership, local farmers, and cooperatives, the MDA coordinated a response that resulted in delisting of these streams in 2014.
