Ground-Water Reconnaissance at Pinnacles National Monument, California

Ground-water supplies at Pinnacles National Monument have been obtained from springs that occur in fractures and along bedding planes of volcanic flows and deposits, and from springs discharged from perched water in a sedimentary fanglomerate formation. The spring-water yield is barely adequate to supply existing camp facilities, and therefore a supplemental water supply is necessary before existing campgrounds can be expanded.

This supplemental water can be supplied by good-quality ground water obtained from shallow wells drilled in the alluvium of Chalone Creek. The yield of properly constructed wells in this area should exceed 10 gallons per minute.