New research from the University of Wyoming (UW) looks at the origin sources for E-coli contamination in two creeks in Teton County.
In 2020, the Wyoming Department of Environmental Quality said Fish Creek and a portion of Flat Creek were “impaired” due to high concentrations of E. Coli, which are bacteria found in the intestines of mammals, environment and food. The U.S. Geological Survey links E. Coli to “direct evidence of fecal contamination.”
The E. Coli levels at the two creeks exceed the state’s standards for “recreational use” – meaning the water is not safe for swimming.
UW graduate student Kelsey Ruehling studied the source of the pollution last year. She found that dog, cattle and sewage were the top three fecal contributors, with higher sewage quantities during the spring and fall.
She presented her newly compiled research to the community last week.
“The septic systems, or leaky sewer lines, are depositing fecal material into the subsurface, which is then being deposited into Fish Creek and Flat Creek when we're seeing these strong pulses in runoff,” Ruehling said.
However, Ruehling noted that high levels of fecal matter and E. Coli often did not occur on the same day. For example, the days with highest fecal matter concentration were in the spring and fall, whereas for E. Coli the increased levels were in mid-summer.
“If E. Coli really was a good indicator of fecal bacteria in this system, we would expect to see a nice positive relationship between fecal contributions to the aquatic bacterial communities as well as aquatic E. Coli,” Ruehling said.
Ruehling said testing for E. Coli is still the most time and money efficient way to test for fecal matter, but she hoped her research would shed light on the fact that Fish Creek and Flat Creek could have high fecal levels on days when E. Coli levels are not as high.
Davi Lee, Teton Conservation District’s water resources specialist, said E. Coli will still be used as a fecal indicator.
“The recommendation that I can easily make is to be really careful about immersion and contact with natural water bodies in your mouth,” Lee said. “Ingestion is the thing that most of these pathogens that we're concerned about really come from.”
Teton County began a two-year project in May to develop a plan to improve the area’s water quality – which would include Fish and Flat creeks.
Ruehling said her research will be published through UW in the near future. The Teton Conservation District will post a recording of Ruehling’s presentation later this week.
