Phosphorus remains the main cause of poor water quality within Lake Winona

Contact: Stephen Mikkelson, 218-316-3887

Focusing on the popular Alexandria area lake, Lake Winona, a Minnesota Pollution Control Agency (MPCA) report called for major reductions in phosphorus levels to meet water quality standards. Consistently high levels of phosphorus in this shallow lake causes excessive algae growth that frequently affects swimming, fishing, and other recreation.

The MPCA report, known as a total maximum daily load (TMDL), establishes the amount of a given pollutant that a water body can accept and still meet water quality standards.

The study identified all sources of phosphorous within Lake Winona and its surrounding watershed, and where reductions will have the greatest impact on restoring the lake. The primary problem is phosphorous that has settled into lake bottom sediments. This legacy phosphorus can be churned up and spread throughout the lake due to wave action or carp stirring up the bottom. Another significant source of phosphorous is stormwater runoff from both urban and rural areas that surround the lake. Phosphorus reductions of 50-60% from these sources are needed for the lake to eventually meet state water quality standards. A key strategy to help restore the lake’s water quality is to reduce and treat runoff from impervious surfaces around the lake, in the City of Alexandria, and LaGrand Township.

After its public-comment period and receiving U.S. Environmental Protection Agency approval, the TMDL will ensure that water quality progress can continue in the watershed.

Lake Winona is the first in a chain of lakes locally referred to as Agnes-Henry-Winona. This chain of lakes drains north through Lake Le Homme Dieu and Lake Carlos, and eventually into the Long Prairie River.

The TMDL report is part of the MPCA’s approach to gauging the health of Minnesota’s 80 major watersheds, each of which will have an approved comprehensive watershed management plan by 2025. After intensive water monitoring, the agency and partners evaluate biological conditions in lakes and streams. The MPCA places waters that fail to meet standards on the Impaired Waters List, and develops information and strategies to restore impaired waters and protect healthy ones.

The draft report is available on the MPCA’s Public notices webpage. Submit comments on the findings of the report to, or request information from Bonnie Finnerty (218-316-3897, 800-657-3864), MPCA, 7678 College Road, Baxter, MN, 56425 by 4:30 p.m. on Wednesday, May 26.

Written comments must include a statement of the respondent’s interest in the report, and the action requested of the MPCA, including specific changes to sections of the draft report and the reasons for making those changes.