Nepstad, James and Wiles, Michael. 1992. GRPEP Final Report: a preliminary examination of contamination in groundwater in the southern Black Hills, including the Madison Aquifer. 68 p.

Abstract

This paper reports the findings and progress of the first half of the second year of study on the groundwater quality at Wind Cave and Jewel Cave. During the first year, elevated concentrations of dissolved metals were discovered in the groundwater at each cave. The two 1993 quaterly samplings taken to date show the groundwater at each cave to be much cleaner (relative to dissolved metals) than measured during the first year. No obvious seasonal variations have been established, although it is now apparent that wide variations in natural water quality are normal. Preliminary studies have shown that the Minnelusa and Madison Formations are likely sources of the metals. Dye tracer tests have been initiated. They will help to establish flow paths and to determine which portions of the formations are likely contributors to dissolved constituents. Analyses of rock samples at several lithologic intervals will help confirm whether the dissolved metals have a natural origin.