Livestock and septic systems contribute to Minnesota River E. coli impairments

Contact: Mary Robinson, 651-757-2525

Water quality in the Minnesota River is expected to improve if a number of strategies are implemented to reduce current Escherichia coli (E. coli) levels, according to a report drafted for the Minnesota Pollution Control Agency. The MPCA invites comments on the draft report through Mar. 6.

The draft report addresses five specific segments, or “impaired reaches,” of the main stem of the Minnesota River. The MPCA investigated bacteria levels, flow records, and water quality over time in order to develop the Total Maximum Daily Load study, or TMDL, for the E. coli bacteria. The TMDL establishes the maximum amount of pollutant the waterbody can assimilate while still achieving water quality standards, and outlines what pollution reductions are needed to meet those standards.

There are two primary sources of concern for E. coli entering the Minnesota River: livestock from unpermitted animal feeding operations, and septic systems that represent public health threats. This includes both faulty septic systems and the illegal use of straight pipes carrying raw sewage from homes or businesses directly to surface waters. The MPCA determined that a handful of other potential sources, including discharge from wastewater treatment plants, municipal storm sewer systems, and permitted animal feedlot operations that are in compliance, are not likely to be substantial sources of E. coli.

The most effective practice to reduce E. coli loads from human sources is to upgrade or entirely replace faulty septic systems. These actions eliminate a fecal bacteria source entirely, and should be a priority. Additional strategies include annual septic system inspections to ensure compliance with state and county codes, and increased education about the real public health risks of septic systems when they are not properly maintained.

Several best management practices could reduce E. coli loads from animal feedlot operations, including better waste management through additional waste storage facilities and more effective land application of manure. Other best management practices involve using filter strips or riparian buffers to filter runoff and trap pollutants before they reach waterbodies. Limiting animal access to streams and providing alternative drinking water supplies for livestock away from streams will reduce E. coli loads, too.

Overall, the level of impairment outlined in this report is low to moderate when compared to the impairment of the Minnesota River’s tributaries; however, addressing failing septic systems and adopting better manure management practices will help reduce bacteria levels and restore the impaired reaches to meet water quality standards for aquatic recreation.

The draft report is available on the MPCA’s Minnesota River bacteria TMDL and strategies report webpage or at the MPCA Mankato office, 12 Civic Center Plaza, Suite 2165, Mankato, MN 56001.

Comments on the draft report should be sent to Scott MacLean, MPCA, 12 Civic Center Plaza, Suite 2165, Mankato, MN 56001, or by email to scott.maclean@state.mn.us. Written comments must include a statement of your interest in the report and the action you wish the MPCA to take, including specific references to sections of the draft report you believe should be changed and the reasons for making those changes. Comments must be received by 4:30 p.m. on Mar. 6.