Rum River Watershed Stressor Identification Report

Over the past few years, the Minnesota Pollution Control Agency (MPCA) has substantially increased the use of biological monitoring and assessment as a means to determine and report the condition of rivers and streams. The basic approach is to examine fish and aquatic macroinvertebrate communities at sites throughout a major watershed. From the data, an Index of Biological Integrity (IBI) score can be developed, which provides a measure of overall community health. If biological impairments are found, then the next step is to identify stressors to the aquatic community. Stressor identification is a formal and rigorous process that identifies stressors causing biological impairment(s) of aquatic ecosystems, and provides a structure for organizing the scientific evidence supporting the conclusions (EPA, 2000). In simpler terms, it is the process of identifying the major factors causing harm to fish, macroinvertebrates and other aquatic organisms. Stressor identification is a key component in the development of Watershed Restoration and Protection Strategies (WRAPS) being carried out under Minnesota’s Clean Water Legacy Act. This report summarizes stressor identification work in the Rum River Watershed (RRW).