Des Moines River Watershed Stressor Identification Report

Stressor identification is a formal and rigorous process that identifies stressors causing biological impairment of aquatic ecosystems and provides a structure for organizing the scientific evidence supporting the conclusions (Cormier et al. 2000). It looks at causal factors – negative ones harming fish and insects, and positive ones leading to healthy biology. Stressors may be physical, chemical, or biological. In simpler terms, it is the process of identifying the major factors causing harm to aquatic life. Stressor identification is a key component of the major watershed restoration and protection projects being carried out under Minnesota's Clean Water Legacy Act. This report summarizes stressor identification work in the Des Moines River Watershed. There were 56 reaches identified with biological impairment in the watershed. The impairments in this report are organized by 10-digit Hydrologic Unit Code (HUC). There are ten HUCs discussed in this report. After examining many candidate causes for the biological impairments, the following stressors were identified as probable causes of stress to aquatic life: DO Eutrophication Nitrate Suspended Sediment Habitat Flow Alteration and Connectivity