Of the water bodies studied, no lakes and few streams in the Minnesota portion of the Missouri River Basin met state standards for supporting aquatic life and recreation — fishable and swimmable — according to a recent report from the MPCA. The agency completed a report on monitoring and assessment of water quality and aquatic life for four watersheds in southwestern Minnesota that are part of the Missouri River basin.
Separated from the rest of the state by the Buffalo Ridge geological formation, the Rock, Upper Big Sioux, Lower Big Sioux, and Little Sioux watersheds lie partially in Minnesota before spilling across the border to Iowa and South Dakota. The study assessed 93 of 181 stream sections in the four watersheds for aquatic life or aquatic recreation. Of these, only three were considered fully supporting of aquatic life, and one fully supporting of aquatic recreation. Fifty three sections were non-supporting of aquatic life and 31 non-supporting of aquatic recreation. None of the lakes in the Missouri River Basin met the aquatic recreation standard.
The impairments are caused by high levels of bacteria, nitrates and sediment. Due to the many impairments, the MPCA sees a great need for exploration of major stressors to water quality. Improving water quality will require changes on the land draining to the basin, especially reducing pollutants from farming practices. Addressing nonpoint source pollution would benefit from identifying features in watersheds that are more prone to be pathways of contamination, and working with landowners to limit potential contaminants from reaching those sensitive areas.
For more details
More information on the watersheds involved in the report: