Des Moines River Basin in Minnesota Monitoring and Assessment Report

The monitoring and assessment report is the first in a series of reports for watershed work conducted in the three Minnesota watersheds of the Des Moines River Basin. The report shares information on monitoring conducted to further information about the watersheds through Intensive Watershed Monitoring (IWM), and assessments on aquatic life, aquatic recreation, and drinking water uses. Subsequent reports will address stressor identification biological impairments, total maximum daily loads (TMDLs), and Watershed Restoration and Protection Strategies (WRAPS) for these watersheds. The three Des Moines River Watersheds are located in southwestern Minnesota, and include Headwaters of the Des Moines River (07100001), Lower Des Moines River (07100002), and East Fork Des Moines River (07100003). The Lower Des Moines and East Fork Des Moines Watersheds extend out of Minnesota into Iowa. This report will only focus on the portions of watersheds within Minnesota. In total, these watersheds drain 1559.6 mi2 in seven Minnesota counties (Cottonwood, Jackson, Martin, Murray, Nobles, Lyon, and Pipestone). Intensive agricultural land use has drastically changed the landscape and the water quality of these watersheds. Only a small percentage of land is undeveloped forest and wetlands and only 1% is open water (lakes, rivers, streams, ditches). The anthropogenic effects of the agricultural land use has greatly diminished the aquatic life and aquatic recreation of the lakes and streams. In the Des Moines River Basin 9% of streams are supporting of aquatic life use and 7% of streams are fully supporting aquatic recreation use. Sixty stream reaches do not support aquatic life use. There is widespread aquatic life impairments due to water chemistry. There are turbidity (19), dissolved oxygen (3), chloride (1), pH (1), eutrophication (3), and ammonia (1) spread throughout the three watersheds. All of the 12 lakes where aquatic life use was assessed were found to be non-supporting the use.