Resource values, instream flows, and ground-water dependence of an oasis stream in the Mojave Desert

An instream flow assessment of an oasis stream in the northeastern Mojave D esert was conducted using the U.S. Bureau of Land Management's value-based process (Jackson et al., 1989). Produced in support of a water right applic ation, the study included an institutional analysis of water availability f or the site, characterization of the hydrology of the aquifer-stream system , and description and quantification of flow-dependent resource values. Spe cific objectives for the assessment were to (1) determine the physical and legal availability of water for management purposes; (2) understand the hyd rology of Beaver Dam Wash, particularly the interaction of surface- and gro und-water systems; (3) develop relationships between streamflow and resourc e values and evaluate flow requirements to maintain resource values; and (4 ) identify and evaluate flow protection strategies and related flow issues for management. The institutional analysis addressed the need for protectio n from extensive groundwater withdrawals that threaten surface flows in the area. The hydrologic characterization described ground-water contributions to streamflow at the oasis and the influence of large floodflows on channe l morphology and ecological sites. The resource assessment focused on criti cal habitat for several special-status fish species, aesthetics and wadeabi lity for recreation users, and consumptive use and ecological needs for rip arian habitat.