Stressor Identification Report for the Vermillion River Watershed Restoration and Protection Strategies

biological impairment in streams in the Vermillion River watershed, in Dakota and Scott Counties, Minnesota. This analysis was prepared using the United States Environmental Protection Agency's (US EPA) and Minnesota Pollution Control Agency's (MPCA) Stressor Identification guidance and the US EPA's Causal Analysis/Diagnosis Decision Information System (CADDIS). CADDIS is a methodology for conducting a stepwise analysis of candidate causes of impairment. CADDIS characterizes the potential relationships between candidate causes and stressors, and identifies the probable stressors based on the strength of evidence from available data. The Vermillion River watershed is located in the southeast part of the seven county Twin Cities, Minnesota Metropolitan Area. Portions of the Vermillion River and its tributaries are designated by the Minnesota DNR as trout waters. Land use within the Vermillion River watershed is primarily agricultural, but parts of the watershed are more densely populated with suburban land uses. Fish and macroinvertebrate community information has been gathered throughout the Vermillion River watershed, which contains a mix of streams designated as both warmwater and coldwater. Two reaches of the Vermillion River main stem and two tributaries – South Creek and South Branch - do not meet State of Minnesota fish and macroinvertebrate standards for biotic integrity. One additional reach of the Vermillion River does not meet the fish biotic standard but does meet the macroinvertebrate standard.