Sediment, phosphorus, and bacteria are big problems for water quality in the Lower Minnesota River watershed

Contact: Mary Connor, 651-757-2629

Many lakes and streams in the Lower Minnesota River Watershed are not meeting water quality standards, according to a new report from the Minnesota Pollution Control Agency (MPCA). Sediment from eroding streambanks, phosphorus from both urban and rural runoff, and bacteria from livestock manure, failing septic systems, and urban stormwater are putting stress on fish and other aquatic life, and making the water less attractive for recreation. The MPCA’s Lower Minnesota River Watershed Restoration and Protection Strategy (WRAPS) report outlines the work needed to improve water quality in the watershed, and to protect waters that are already meeting standards.

The Lower Minnesota River Watershed in south-central Minnesota covers 87 miles of the Minnesota River, from Ottawa, Minnesota, to the river’s confluence with the Mississippi. The 1,835-square-mile watershed also includes the Minnesota Valley National Wildlife Refuge, 133 lakes larger than 10 acres, and 2,482 miles of tributaries to the Minnesota River. Land use ranges from almost exclusively row-crop agriculture in the west to residential suburbs and urban industry in the northeast.

The MPCA began monitoring the watershed in 2014, as part of its statewide water quality monitoring effort. The data gathered by the agency shows that of the 103 lakes and 117 stream sections monitored:

  • 84% of streams don’t meet standards for supporting fish and other aquatic life
  • 95% of streams had bacterial contamination above health-based limits
  • 55% of lakes had phosphorus or nitrogen levels that exceeded standards

Sediment, phosphorus, and bacteria are the primary water pollutants in the watershed. Excess sediment clouds the water and can inhibit beneficial plants and harm fish and bugs. High bacteria levels may make water unsafe for swimming and other recreation. Excess phosphorus can cause algae growth, including harmful blue-green algae, which is toxic to dogs and humans.

However, not all the news is bad. Four lakes — Crystal, McMahon, Mitchell, and Bryant — are now meeting water quality standards that they failed to meet previously. The improvements are the result of successful restoration efforts by state and local entities.

“The Lower Minnesota River WRAPS report recommends ways to improve water quality,” says Wayne Cords, regional watershed manager for the MPCA. “Many of them are focused on agriculture because it’s the dominant use of land in the watershed, but all watershed residents can have an impact.” Meaningful public participation helped shape the report recommendations, and participants identified specific lakes and streams as priorities for action.

Learn more about the studies and overall goals for the basin at an open house on Wednesday, July 31, from 4-7 p.m., at the Sibley Park Pavilion, 900 Park Lane, Mankato.

These reports are part of a larger effort to restore water in the Minnesota River Basin. Learn more on the MPCA website. To comment, use the form on the basin web pages or send written comments to Bryan Spindler, MPCA, 12 Civic Center Plaza, Suite 2165, Mankato, MN 56001 by 4:30 p.m. on Friday, Sept. 20.