Chloride Toxicity In The Upper South Fork Of The New River: Implications For Watershed Health And Aquatic Life

This Study investigates Chloride (Cl-) trends in the Upper South Fork of the New River associated with the transport of de-icing road salts into stream networks through the mechanism of surface water runoff. Collection of water samples over the course of one year provided Cl- concentration data both in association with major precipitation events and during base flow conditions for six sub-basins of the Upper South Fork of the New River Watershed. Correlation analysis examined the relationship between both annual and seasonal Cl- concentrations and land-use/ land cover characteristics for each sub-basin. The relationship between specific conductivity and Cl- enabled the extrapolation of Cl- from a six-year conductivity record provided by data loggers at each sub-basin outlet. Results show a strong correlation between impervious surfaces and Cl- concentrations. Results also show a strong seasonal signature in highly developed sub-basins where Cl- levels peak during the winter months in conjunction with road salt application. Finally, the six-year Cl- record, which shows concentrations in excess of toxicity thresholds with much higher frequency in the sub-basins with comparably higher impervious surface, highlights the importance of this research for on-going and future management-related discourse in the Upper South Fork of the New River.