The Furnace Creek basin is an area of 8.95 square miles, about three- fourths of which is underlain by metamorphic rocks of low permeability. Reported yields for 14 wells in these rocks range from 1 to 60 gal/min (gallons per minute), with a median of 7.5 gal/min.
The northern part of the study area consists of highly permeable carbonate rocks. Nondomestic wells in these rocks typically yield from 200 to 300 gal/min and one well yields 1,200 gal/min.
Ground-water discharge from a 4.18-square-mile drainage area underlain by Precambrian granitic and hornblende gneiss averaged 868,000 gallons per day per square mile from October 1983 through September 1985. Thus, as much as 3,630,000 gallons per day could be pumped from wells in this area on a sustained basis. However, pumping this amount would have major adverse effects on streamflow.
A water-budget analysis for March 1984 to February 1985 showed that precipitation was 52.16 inches, streamflow was 26.38 inches, evapotranspiration was 29.29 inches, ground-water storage decreased by 5.94 inches and diversions made by Womelsdorf-Robesonia Joint Authority for water supply totaled 2.43 inches. Precipitation during this period was above normal.
Four of 18 wells sampled for water quality had iron, manganese, or nitrate concentrations above the U.S. Environmental Protection Agency's recommended limits. The crystalline rocks in the study area yield soft to moderately hard water that is generally acidic.
