Reports finalized on bacteria in Cottonwood and Redwood River watersheds

Contact: Forrest Peterson, 320-441-6972

St. Paul, Minn. — Reports addressing pollution from bacteria in sections of the Redwood and Cottonwood rivers in south central Minnesota have been approved by the U.S. Environmental Protection Agency (EPA). Now that the reports have been finalized, state and local agencies will focus on projects to reduce the level of pollution.

The Minnesota Pollution Control Agency (MPCA) had placed the sections on the state’s impaired waters list for exceeding the water quality standard for fecal coliform (E. coli) bacteria. Called Total Maximum Daily Loads (TMDL), the reports support on-going work in the watersheds to reduce bacteria pollution to an acceptable level.

Most bacteria are beneficial, serving as food for larger organisms, and playing key roles in decomposition of organic matter, fixation of nitrogen and digestion of food. However, about 10 percent are harmful. Known as pathogens, these bacteria can release toxins causing sickness or death if ingested by humans.

Sources of bacteria include failing or noncompliant septic systems, wastewater treatment plant bypasses, unsewered communities, livestock manure from feedlots and land application, and stormwater from cities and commercial areas. Domestic pets and wildlife are lesser possible sources.

Efforts to reduce bacteria in surface waters can include upgrading individual sub-surface sewage treatment systems, ensuring compliance of wastewater treatment plants, implementing wastewater treatment in unsewered communities, preventing runoff from livestock facilities, using proper manure land application procedures and managing urban stormwater.

The Cottonwood River enters the Minnesota River near New Ulm. It drains a 1,313-square-mile area in sections of Lyon, Murray, Cottonwood, Redwood and Brown counties. Land use is primarily agricultural, accounting for approximately 88 percent of the available acres.

The Redwood River flows into the Minnesota River near Redwood Falls in southwestern Minnesota. There are eight municipal wastewater treatment plants in the watershed, which serve nearly 16,000 people. Agriculture accounts for approximately 85.5 percent of land use in the 705-square-mile watershed.

The TMDL reports are part of a nationwide effort under the federal Clean Water Act to identify and clean up pollution in streams, rivers and lakes. Every two years, states are required to submit a list of impaired waters to the EPA, and then develop TMDLs. Eight sections of both rivers or tributaries are listed as being impaired for bacteria.

The TMDL is a scientific study that calculates the maximum amount of a pollutant a water body can receive, known as the “loading capacity,” without exceeding water quality standards.

Copies of the reports are available on the MPCA’s Cottonwood River TMDL webpage and the Redwood River TMDL webpage.