2011 - North Fork Crow River Watershed Biotic Stressor ID Report

Water quality and biological monitoring in the NF Crow watershed has been active for several decades. As part of the MPCA’s new Intensive Watershed Monitoring (IWM) approach, monitoring activities increased in rigor and intensity during the years of 2007-2010. The data collected during this period, as well as historic data obtained prior to 2007, were used to identify stream reaches that lacked healthy fish and macroinvertebrate assemblages. Fish and macroinvertebrate data were collected at most biological monitoring stations, and were assessed independently, making it is possible for a given stream reach to be impaired for one or both of these biological indicators.

The result of this assessment monitoring effort was the listing of select NF Crow watershed streams as “impaired” for aquatic life.The biologically impaired stream reaches in the watershed include the entire NF Crow and Crow River mainstem, and numerous tributary streams. NF Crow watershed streams that are not listed as impaired are either not yet assessed (lacking monitoring data) or are showing good to exceptional biological integrity based

on current data. For a complete report on the condition of NF Crow watershed streams and lakes, see the Phase I IWM report (2011).


The report showed that for the headwaters of the NFCR watershed showed that the combination of a low drainage area, extensive ditching, and a highly agricultural landscape appears to be limiting biological integrity for fish in the extreme headwaters of the NF Crow.  Fish communities did not contain sensitive species, abundance was low overall and those fish present were species that were tolerant of degraded chemical and physical habitat conditions. These observation are an indicator of poor quality of the stream habitat.

Macroinvertebrate, or aquatic insects, were also studied in the headwater region. Five locations were observed in the NFCRWD boundary, and two are within drainage ditches. Scores at these sites indicate impairment. Results showed a lack of sensitive species, and an abundance of filter feeder.  This may indicate that these stream reaches contain higher than normal amount of organic particulate matter.