Buried valleys contain 200 to 300 feet of fine sand, silt, and clay. Drilled wells yield meager supplies unless encountering thin, isolated sand and gravel lenses. 10 Yield less than 3 gallons per minute. Impermeable deposits, basically clay overlying shale or shaley sandstone, provide a very poor area for even minimal domestic supplies. Brackish water and dry wells are common.
Storage is necessary to supply peak demands.