Intensive watershed monitoring began in the Big Fork watershed in 2010. Local citizens, collaborating with Soil and Water Conservation Districts of Itasca and Koochiching Counties, Itasca Community College, Itasca Water Legacy Partnership, Big Fork River Board and the state’s Department of Natural Resources and Pollution Control Agency are working to improve and protect its waters. Limited land uses for industry, housing, and roads have led to high water quality in the Big Fork system, however challenges remain in maintaining this high quality water.

KEY ISSUES

The identified impairments found in lakes and streams are:

• High levels of mercury in fish tissue which limit fish consumption; • Nutrient impairments;

• Low dissolved oxygen in streams, which may be due to natural causes; and,

• Biological impairments for fish and aquatic macroinvertebrates.

HIGHLIGHTS

• The Big Fork River and 12 lakes were found to have fish with measurable levels of mercury.

• Fish tested for PCBs (polychlorinated biphenyls) and/or PFOS (perfluorooctane sulfonate) had concentrations below the impairment threshold or detection limit.

• Eleven large streams or stream segments were assessed for aquatic recreation; all had low levels of bacteria and were fully supporting aquatic recreation.

• Low oxygen levels in the Upper Bowstring River and Gale Brook/Rive River sub-watersheds likely due to natural causes or conditions.

• Non-support for invertebrates in the Middle Big Fork sub-watershed. • Non-support for fish and invertebrates in the Bear River sub-watershed.

• Dinner Creek sub-watershed is in need of further study to clarify the cold water or warm water classification.

• Based on monitoring the amount and types of fish and invertebrates found in the streams of the watershed, 33 of the 41 streams assessed supported aquatic life, six did not support the aquatic life, and two streams did not have enough information to make an assessment.

Twelve stream stations were sampled for biology and chemistry. These locations included the outlets of major tributaries such as the Bowstring, Popple, Sturgeon, Dinner Creek, Bear River and Caldwell Creek. In addition, local partners and the MPCA sampled 120 lakes in the Big Fork River watershed; of those, all but six met lake standards for aquatic recreation. In 2012, a holistic approach was taken to assess this data from streams and lakes in the watershed to see if they support aquatic life, recreation and fish consumption. During this process, some stream segments were not assessed due to insufficient data sets and modified stream channels.

This work will be re-visited in 2020.

Jessie Lake has a TMDL process for excess nutrients, completed in 2011.