GROUND -WATER CONTRIBUTIONS TO DEATH VALLEY FROM SOUTHEAST CALIFORNIA DESERT BASINS

The Great Basin area of southeast California contributing flow to Death Valley is defined by the regional potentiometric surface. Prior to the current Death Valley regional flow system (DVRFS) ground-water model, contribution from the California part of the Death Valley flow system was largely excluded from consideration. The California contributing area, of about 20,000 square miles, is bordered on the west by the Sierra Nevada, on the south by the San Gabriel and San Bernardino Mountains and on the southeast by a regional ground-water divide separating the Death Valley flow system and the Colorado River flow system. While basically a complex of rain shadow deserts, by far the greater part of the region is arid to semi-arid, but great ranges of mean annual precipitation (2 to 20 inches) and mean annual temperatures (27 to 77 degrees F.) accrue from elevations that range from below sea level to over 14,000 feet above sea level. Most precipitation, the source of recharge to ground water, occurs at higher elevations. The greatest recharge occurs in the high ranges of bordering basins southwest and west of Death Valley. The basins Panamint, Saline, Eureka, Racetrack Playa and Deep Springs Valleys are each topographically closed and contribute ground water to Death Valley. Although ground water discharges at the valley floors of Panamint, Saline and Deep Springs Basins by thermal springs and evapotranspiration, there is an excess of ground-water recharge to these basins over ground-water discharge. It is estimated from water budgets that these basins contribute about 30,000 cubic meters per day (cmd)to Death Valley. Ground water from the Owens River Valley, within the Death Valley flow system, contributes minor ground-water flow to Death Valley because of the generally low permeability of the rock masses underlying and separating the basins. The Mojave River basin receives recharge largely to alluvial materials by infiltration of runoff from the bordering mountains to the south. Infiltration of precipitation within the Mojave River basin and the other more arid basins within the Death Valley flow system, including Indian Wells Valley, Searles Lake Valley, Mojave River, Soda Lake Valley, Silver Lake Valley, Silurian Valley and others, is small. Ground water contribution to Death Valley from these arid basins is probably a few thousand cmd based on Darcy calculations of flow.