A recent study from the Minnesota Pollution Control Agency (MPCA) details excessive levels of algae affecting recreation, and fish and aquatic insect communities in a specific portion of the Redwood River in southwestern Minnesota just before the river enters the Minnesota River.
The excessive algae growth is due to high levels of phosphorous in the river, causing that segment of the river to be impaired for excessive nutrients (eutrophication).
The drainage area of the impaired river segment covers portions of six counties: Lincoln, Yellow Medicine, Redwood, Lyon, Pipestone, and Murray.
The study, known as a total maximum daily load study (TMDL), establishes the amount of a pollutant (in this case, phosphorous) that a water body can accept and still meet water quality standards. The study also estimates the amount of reduction needed to meet standards.
Since 1994, local partners in the Redwood River Watershed have invested more than $9 million in implementing best management practices, water monitoring, and educational programming that have reduced sedimentation by more than 27,276 tons per year. Excessive sediment is the root cause of many water quality impairments in the watershed.
Protection strategies
The MPCA and its partners identified several strategies to build upon efforts by the Redwood Cottonwood Rivers Control Area and soil and water conservation districts that have already led to water quality and habitat improvements (see MPCA Healthier watersheds accountability report). These strategies/projects include:
- Grade stabilization structures and practices (e.g., water and sediment control basins, grassed waterways) in high-sloped areas, which include two designated Department of Natural Resources trout streams (the Redwood River in Camden State Park, and Ramsey Creek near Redwood Falls).
- Soil health education and outreach.
- Restoration and protection strategies for lakes and stream reaches popular for recreational use (Lake Benton and Norwegian Creek, Redwood River in Camden State Park, Lower Ramsey Creek).
- Restoration and protection strategies for lakes and stream reaches that are nearly impaired or barely impaired in Three Mile Creek and Clear Creek, School Grove Lake, West Twin Lake, and Sanderson Lake.
- Protection of vulnerable and sensitive groundwater areas.
MPCA welcomes feedback on the report
The MPCA invites the public to review and share feedback on the Redwood River eutrophication TMDL study including suggestions for protection and restoration strategies as they relate to aquatic life (fish and aquatic insects) and aquatic recreation.
The draft TMDL study can be found on the MPCA’s website: Redwood River Watershed.
A separate TMDL study covering the entire Redwood River Watershed was recently approved by the EPA and is also available on the watershed web page, along with a recently approved watershed restoration and protection strategy (WRAPS) report that recommends strategies for restoring impaired areas of the watershed and protecting areas at risk of becoming impaired.
Comments may be submitted online or by US mail to the following address: Minnesota Pollution Control Agency; c/o Michael Weckwerth; 504 Fairgrounds Road; Marshall, MN 56258. Submit your comments by Nov. 15, 2023.
Comments must include a statement of your interest in the report(s) and the action you are requesting from the MPCA, including specific changes to sections of the draft report(s) and the reasons for making those changes.
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