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Characterization of chloride and conductivity levels in the Bitter Creek Watershed, WY
Citation:
Cormier, S., Y. Wang, AND C. Wharton. Characterization of chloride and conductivity levels in the Bitter Creek Watershed, WY. U.S. Environmental Protection Agency, Washington, DC, 2022.
Impact/Purpose:
Portions of the Bitter Creek watershed are Clean Water Act Section 303(d)-listed as impaired for chloride. Water bodies that are listed as impaired undergo an assessment process to estimate total maximum daily loads (TMDLs) that, if achieved, are expected to improve water quality and thus meet designated uses. Wyoming Department of Environmental Quality (WDEQ) was interested in understanding whether chloride in Bitter and Killpecker creeks may be naturally high, warranting site-specific criteria. In response to WDEQ’s interest, U.S. EPA investigated whether chloride levels are naturally high in these streams and how chloride concentrations expected to protect 95 percent of aquatic genera in these streams compare to Wyoming’s chloride criteria applicable to the Bitter Creek watershed. Owing to the arid conditions, background conductivity and chloride levels were characterized for surface flow and ground water flow conditions. Natural chloride levels were found to be less than current water quality criteria for Wyoming. Although the report was prepared for USEPA Region 8 and OST, Office of Water, the report will be of interest to the WDEQ, Sweetwater County Conservation District, and the regulated community.
Description:
In response to a request for scientific support to assess whether chloride in Bitter and Killpecker Creeks in Wyoming may be naturally high, warranting site-specific criteria, the USEPA Office of Research and Development is providing for USEPA Region 8 use a characterization of background SC and ionic concentrations in the Bitter Creek watershed; estimates of SC and chloride levels expected to result in the extirpation of 5 percent of genera from streams in the watershed; and recommendations for estimating background SC and chloride for surface water- and ground water -dominant conditions. The attached report was internally reviewed by two EPA scientists and externally reviewed by two experts in the field. The final report was cleared through the Watershed and Ecosystem Characterization Division according to the Center for Environmental Measurement and Modeling standard protocols.
URLs/Downloads:
12 FINAL BITTER CREEK REPORT 20220803ALTTEXT.PDF (PDF, NA pp, 4345.196 KB, about PDF)14 FINAL BITTER CREEK REPORT APPENDICES20220727ALTTEXT.PDF (PDF, NA pp, 2241.713 KB, about PDF)