Sources and effects of mining-related and natural acid rock drainage quantified using tracer dilution, Coal Creek watershed, Gunnison County, Colorado

Metal-laden, acidic drainage from the Standard Mine and the naturally occurring iron fen and gossan in the Coal Creek watershed in Gunnison County, Colorado have been implicated as major contaminant sources contributing to the degradation of Coal Creek. The abandoned Keystone Mine is also located in the watershed. Drainage from the Keystone Mine has been treated at the Mount Emmons treatment facility since 1981. Site specific analysis quantifying the impact of implicated as well as unidentified metal sources on Coal Creek had not been previously conducted. A spatially detailed investigation of contaminant sources was performed to assist the Environmental Protection Agency and a Crested Butte community group, the Coal Creek Watershed Coalition, in development of remedial plans. Low flow conditions are typically considered most toxic to aquatic life as contaminant concentrations are greatest as a result of minimal dilution. (Abstract shortened by UMI.)...