FECAL COLIFORM TOTAL MAXIMUM DAILY LOAD – NORTH BRANCH OF THE SUNRISE RIVER

Jerry Spetzman, Chisago County
Craig Affeldt, Minnesota Pollution Control Agency
Greg Johnson, Minnesota Pollution Control Agency
Chris Zadak, Minnesota Pollution Control Agency
Mary Darragh Schmitz, Chisago County
Lisa Thibodeau, Chisago County
Craig Mell, Chisago Soil and Water Conservation District
Pat Conrad, Emmons and Olivier Resources, Inc.
Andrea Plevan, Emmons and Olivier Resources, Inc.

In 1998, the Minnesota Pollution Control Agency (MPCA) listed the North Branch of the Sunrise River as an impaired water, under Section 303(d) of the Clean Water Act. The river, from its headwaters near Weber in Isanti County to its confluence with the main stem of the Sunrise River near Hay Creek in Chisago County, was listed as impaired for primary contact recreation and swimming. Over a period of 20 years, data have shown often excessive levels of fecal coliform bacteria loading in these waters, especially during times of increased flow due to rain or snow melt.

The indicator for this impairment, fecal coliform, is a group of bacteria that lives in the intestines of warm blooded animals, including humans. Its presence means the water is likely to have been contaminated by human or animal feces, indicating the possible presence of waterborne pathogenic bacteria, viruses or protozoa. These organisms can cause gastric or diarrheal diseases, including such diseases as typhoid or cholera.

The fecal coliform bacteria found in the North Branch of the Sunrise River came from a number of different sources. This Total Maximum Daily Load (TMDL) study looked at a number of different possible sources to try to pinpoint specific sources of the pollution. Point sources such as the North Branch waste water treatment plant were examined and found not to be a substantial source of fecal coliform. Non-point sources such as poorly functioning individual sewage treatment systems, unregulated livestock facilities, and pastures near streams and the river were the main sources of fecal coliform contamination in the watershed.

This study assessed the current fecal coliform concentrations in the river and determined the TMDL of fecal coliform which the river could accept and still meet Minnesota water quality standards for fecal coliform. Loading capacities were allocated among point sources (wasteload allocation), nonpoint sources (load allocations) and a margin of safety. A loading capacity (i.e. TMDL) is the product of stream flow for the impaired reach and the water quality standard. Five flow zones, ranging from low flow to high flow, were utilized so that the entire range of conditions is accounted for in the TMDL. A watershed-wide reduction of approximately 52% in fecal coliform loadings would be needed to comply with Minnesota water quality standards.

The strategy to bring about the necessary reductions is outlined in the implementation section of the report. The next step will be the development of an implementation plan to identify specific measures to be taken to remove the fecal coliform impairment.