Cottonwood River Watershed is home to Little House on the Prairie’s Plum Creek
New reports by the Minnesota Pollution Control Agency (MPCA) detail impairments affecting recreation, and fish and aquatic insect communities in the Cottonwood River Watershed in southwestern Minnesota. The reports recommend building upon many actions local groups have already taken to address water quality in the watershed.
Local partners, including the area Soil and Water Conservation Districts (SWCDs) and the Redwood-Cottonwood Rivers Control Area (RCRCA), have implemented hundreds of best management practices (BMPs) to improve water quality in the Cottonwood River Watershed including the Plum Creek Subwatershed. Plum Creek is the stream Laura Ingalls Wilder wrote about in her book series “Little House on the Prairie.”
The strategies address water quality issues caused by significant landscape alterations including the straightening of streams and extensive ditching that can increase sedimentation. In addition, high flows associated with spring runoff and summer storms, and extended periods of low flows can negatively affect stream habitat. The impacts of higher intensity storms and more severe droughts are amplifying these conditions.
The reports outline impairments and highlight additional protection strategies.
Streams — Seventy of the 75 stream reaches in the watershed were assessed for aquatic use. Only 19 stream reaches fully supported fish and bug communities, and no streams fully supported recreation. Factors affecting aquatic communities include poor habitat, low dissolved oxygen levels, excessive amounts of sediment in the water, and barriers to fish passage such as dams and perched culverts.
Lakes — Of 25 lakes in the watershed greater than 10 acres in size, 7 do not support aquatic recreation due to excessive amounts of nutrients, mainly phosphorus, which can cause nuisance algae blooms. Excessive nutrients can also have detrimental effects on fish and insect communities. Sleepy Eye Lake was previously listed as having impaired aquatic recreation, but the lake now meets standards.
Protection strategies
The MPCA and its partners identified several strategies to build upon efforts that have already resulted in water quality and habitat improvements (see MPCA Healthier Watersheds Accountability Report). Additional strategies include:
- Urban stormwater management
- Conservation farming practices, especially in upland areas (includes increased crop residue and other steps to treat/prevent sediment/nutrient runoff)
- Septic system improvements
- Removing barriers to fish passage
- Short- and long-term water storage
TMDL and WRAPS reports
One recently released report is a total maximum daily load (TMDL) study. A TMDL establishes the amount of each pollutant that a water body can accept and still meet water quality standards. The TMDL also estimates the amount of reductions needed to meet the standards. TMDLs are required by the federal Clean Water Act.
The TMDL report for the Cottonwood River Watershed addresses 11 total suspended sediment (TSS) impairments, 8 bacteria impairments, and 7 lake nutrient impairments.
The second report, a watershed restoration and protection strategy (WRAPS) report, is required by the state Clean Water Legacy Act and uses TMDL reports, monitoring results, and other information to develop strategies for restoring polluted waters and protecting healthy ones. Local partners will use this information to develop detailed implementation plans and set priorities for projects.
The MPCA invites the public to share feedback on these reports including suggestions for additional or revised protection and restoration strategies as they relate to aquatic life and aquatic recreation. The draft reports are available on the MPCA’s website: Cottonwood River Watershed
Comments may be submitted online at Public comments 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 November 9, 2022.
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.