By Carlin Girard, Water Resources Specialist and Associate Director
As a local governmental entity that in part focuses on water quality, Teton Conservation District is providing the following blog post to give context and further detail on the recent addition of Fish Creek and Flat Creek to the Draft Wyoming Impaired Stream List due to E. coli exceedances.
Primary contact recreation standards for E. coli, which have been exceeded in Fish Creek and Flat Creek, are intended to provide water quality that is safe for human contact by reducing the risk of human ingestion of fecal pathogens.
In 2017, the Wyoming Department of Environmental Quality (WYDEQ) completed summer E. coli sampling on Fish Creek, Flat Creek, and the Snake River. E. coli sampling is a routine sampling parameter that is used as a proxy for the risk of fecal contamination. The E. coli that was measured in this study is referred to as a ‘fecal indicator bacteria,’ which is very different from the pathogenic E. coli strain O157:H7 that often makes national news due to outbreaks. This is an important distinction because E. coli bacteria are present in the gastrointestinal systems of all warm-blooded animals, whereas pathogenic strains are far less common. Nevertheless, fecal contamination in water has been studied at length, and E. coli can be related to the likelihood of other fecal pathogens. As such, we use E. coli to measure the amount of fecal material entering waterbodies as a cheap and straightforward method of inferring the risk of ingesting pathogens.
Fecal contamination in water is a common water quality issue worldwide and can affect human health. The 2017 study was not the first of its kind here in Teton County. In 2003, an E. coli quantification study completed by Teton Conservation District was also accompanied by a study to help define where E. coli was originating from. The 2003 E. coli quantification shows that E. coli concentrations in Flat Creek have not changed much, but concentrations in Fish Creek have increased. So, what caused this increase?
Summarized results from the Teton Conservation District 2003 E. coli source tracking study, showing proportional loading of E. coli sources from samples collected.
Proportional loading of the human-oriented E. coli from 2003 sampling. Human-oriented sources consisted of less than 20% of the total E. coli contribution to the streams sampled in 2003.
In Teton County, addressing fecal contamination in streams is a somewhat complex issue. Teton Conservation District’s 2003 study showed that E. coli originated from a wide variety of sources and identified the proportional contribution of E. coli from different sources in both Fish Creek and Flat Creek. The study identified that over 50% of the total E. coli load originated from avian, rodent (think beaver and muskrat), and deer/elk. Furthermore, the 2003 study showed that of the E. coli found in the Fish Creek and Flat Creek basins, less than 20% of it originated from sources related to human activities; more specifically, 7% originated from dogs, 6% from wastewater, 4% from bovines, and 2% from horses. While these results reflect the significant proportion of E. coli contributed by wildlife, they have also prompted implementation of Teton Conservation District projects that directly mitigate fecal inputs to streams. Finally, the 2003 results demonstrate the importance of E. coli source data collection in order to identify the best route to reduce E. coli concentrations.
Our interest in source tracking of E. coli is also found at the state level—a recent Wyoming Water Research Program grant has initiated a University of Wyoming graduate student (Kelsey Ruehling) research project, which is already underway. With guidance from University of Wyoming professors Sarah Collins and Bledar Bisha, this study will use current genetic techniques to assess the sources contributing to E. coli concentrations in Fish Creek and Flat Creek from water samples collected in 2020 and 2021. Teton Conservation District considers this study an essential step in addressing the impairment that has been identified by WYDEQ. The ‘impaired’ status of Fish and Flat Creek’s due to E. coli concentrations is intended to recognize a potential human health concern, but it also establishes a route and access to resources to address the issue. Identifying the source of E. coli concentrations will allow the community to funnel State and Federal resources that are now available to where it matters most. In the meantime, pick up your dog poop.
Learn more:
TCD’s 2003 microbial source tracking study presentation (readers should note that WYDEQ E. coli standards have changed since this presentation was created)
WYDEQ’s Memo pertaining to E. coli data collection in Fish and Flat Creek