Recreational Water Quality Monitoring in the French Broad River Basin: a Preliminary Analysis of Seven Potential Escherichia coli Estimator Sites

December 3 or 5, noon – 2:00pm, via Zoom

Kari Kvittem

Dr. David Gillette

McCullough Fellowship: Department of Environmental Science

Water quality monitoring and mitigation have posed ongoing challenges for stakeholders in the French Broad River Basin. In 2022, The North Carolina Department of Environmental Quality (NCDEQ) designated nineteen miles of the French Broad River as impaired due to consistently high levels of sediment and Escherichia coli (E. coli), a
bacterium indicating potential health risks in waterways. In response, NCDEQ partnered with MountainTrue, a local non-profit, to develop a near real-time E. coli estimator at Pearson Bridge in Asheville, NC, through predictive modeling based on the correlation between E. coli levels and turbidity. While effective, this model is site-specific and only applicable to Pearson Bridge. To improve the accuracy and sustainability of recreational water quality monitoring, MountainTrue and NCDEQ are working to develop an E. coli estimator in each county within the watershed. This study supports these efforts through a preliminary analysis to determine the strength of this correlation at seven potential sites. A total of 465 water samples were collected between May and September from 2019 to 2024, analyzed for E. coli concentrations (MPN/100 mL), and measured for
turbidity (NTU). Regression models indicate that the sites best-suited for further development are Champion Rosman, Hap Simpson Park, Canton Recreational Park, Hot Springs Bridge and Bent Creek Recreational Park, as turbidity explains more than 50 percent of the variance in E. coli at these sites. In contrast, models for Big Laurel
Creek and Horseshoe Access explained approximately 35 percent of the variance, suggesting these sites may be less suitable for estimator development. The completion of estimator models will require additional data to improve model strength, in-depth statistical analyses and the installation of USGS-maintained turbidimeter gauges at each site.