Escherichia coli (E. coli) is a group of bacteria commonly found in the intestines of warm-blooded animals, including people. E. coli in fresh water can indicate the presence of pathogens (disease-causing organisms) from animal or human feces. In 2017, Wyoming Department of Environmental Quality found that sites on Fish Creek and Flat Creek exceeded E. coli concentrations deemed safe for full body contact recreational activities.

Sources of E. coli

Wildlife – Elk, deer, moose, waterfowl, rodents, etc.
Livestock and pet waste
Municipal wastewater treatment facilities
Individual septic systems

E. coli source study of Fish Creek and Flat Creek (2003)

Effects of E. coli

May pose health risks to people fishing and swimming in a waterbody.
When E. coli exceeds the permissible level in recreational water, it results in the closing of beaches, ponds, lakes and fishing areas. Can cause cloudy water, unpleasant odors and decreased levels of dissolved oxygen.