Studies on Zumbro River watershed: Trout streams need protection, others need work

Contact: Cathy Rofshus, 507-206-2608

Some waters are in good shape while many need work in the Zumbro River watershed in southeastern Minnesota, according to recent studies by the Minnesota Pollution Control Agency (MPCA), Zumbro Watershed Partnership and other partners.

This watershed drains 909,000 acres in Olmsted, Dodge, Wabasha, Goodhue, Steele and Rice counties. The landscape is diverse, with most of it used for agriculture. Yet its cities are growing, most notably Rochester, home of the Mayo Clinic. The lakes and streams vary in water quality and the groundwater is sensitive to pollution.

The good news includes:

  • Although still at elevated levels, run-off pollutants such as phosphorus that cause algal blooms and sediment that make water cloudy, have shown long-term decreasing trends.
  • Continued declines in phosphorus from wastewater treatment plant discharges to the river and its tributaries, including the city of Rochester’s plant.
  • Nearly all designated trout streams here are in good shape and protecting them is critical. One protective strategy is to ensure adequate flow, meaning government entities need to carefully consider future permitting of stream water for irrigation, factory processes and other uses.

On the bad news side:

  • Stream habitat has degraded at most of the sites sampled, hurting the populations of bugs that are an important part of the ecosystem.
  • Levels of nitrogen are high at times, and some streams and springs show an increasing trend of nitrogen levels over the long-term. Nitrogen in drinking water can be harmful to humans, and in streams can be toxic to fish and bugs.
  • Rice Lake in Steele and Olmsted counties fails to fully meet the standard for aquatic recreation because of high levels of phosphorus.
  • Twenty sections of streams fail to fully meet standards for aquatic life and recreation because of bacteria levels that can make the water unsafe for swimming and/or sediment that makes the water cloudy.

The two study reports are open for public comment through Sept. 20:

  • The Total Maximum Daily Loads (TMDL) and the Watershed Restoration and Protection Strategies (WRAPS) are companion documents that quantify pollutant levels, identify pollution sources, and propose ways to return water quality to an acceptable level.
  • The WRAPS Report summarizes information, tools and stakeholder input that can be used by local governments, landowners and others to decide on the best strategies and most effective places for those strategies to protect and restore water quality.

For example, improving fertilizer efficiency, and adding perennial and cover crops are important strategies in the Zumbro because more than 80 percent of the nitrogen in waters comes from fertilizer loss to drainage tiles or groundwater.

Other strategies focus on controlling erosion, managing stormwater, protecting drinking water, managing waste, and protecting perennial lands.

For more information, see the full study reports on the MPCA’s Zumbro River watershed webpage. The MPCA encourages those interested in the Zumbro to review and provide feedback on the study reports. Comments should be submitted in writing by 4:30 p.m., Sept. 20, to Justin Watkins, MPCA, 18 Wood Lake Drive S.E., Rochester, MN, or to He is available to answer questions at 507-206-2621.

Written comments must specify which report you are commenting on, 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. You must state the specific reasons for your position.