Geological Survey Water-Supply Paper 1475-K Ground-Water Reconnaissance at Pinnacles National Monument, California

A water sample was collected at the end of the pumping test and was analyzed by the Quality of Water Branch, U.S. Geological Survey, Sacramento, Calif. The results of the analysis show that the ground water in the alluvium of Chalone Creek is of good quality, pH 6.7, medium hardness, and contains 280 ppm (parts per million) of dissolved solids. The following table shows in detail the results of the analysis.

Chemical analysis, in parts per million, of water from well 36R1, sampled July 21, 1969

During the preliminary test pumping of well 35R1 a strong hydrogen sulfide odor was noted at the time the pumping level was at or near the bottom of the well (37 feet). The sulfurous odor disappeared from a sample after allowing the sample to stand for a few minutes. The sulfurous odor may be the result of water moving into the alluvium from the nearby fault; however, no increase in water temperature was noted. The sulfurous water is believed to be sealed off from the well by the cement plug.