Mississippi River-Sartell Watershed Stressor Identification Report

Since 2007, the Minnesota Pollution Control Agency (MPCA) has substantially increased the use of biological monitoring and assessment as a means to determine the condition of the state's rivers and streams. This basic approach is to systematically examine fish and aquatic macroinvertebrate communities throughout the state's 80 major watershed. From these data, an Index of Biological Integrity (IBI) score is calculated, which provides a measure of overall community health (MPCA 2017(a) & MPCA 2017(b)). For assessment purposes, rivers and streams are divided into specific reaches and are assigned a three-digit Waterbody Identification (WID) number. A WID (stream reach) can be of various lengths and have one or more biological and chemical sampling stations on it. Of the 34 WIDs assessed for aquatic life in the Mississippi River – Sartell (MRS) Watershed by the MPCA in 2018, fourteen were designated impaired for aquatic life (Table 1). Seven were impaired for aquatic life due to nonsupport of the fish community (FIBI), three for nonsupport of the macroinvertebrates (MIBI), and four for nonsupport of both communities. Comprehensive results of the Intensive Watershed Monitoring (IWM) effort and assessment of the MRS Watershed were published in the Mississippi River- Sartell Monitoring and Assessment Report (MPCA 2019), hereafter referred to as the M&A Report.