A water resource investigation using GIS and remote sensing methods, Washoe Valley, Washoe County, Nevada

Population growth and the trading of water rights have brought renewed interest in available water resources in Washoe Valley, a hydrographic area located in west central Nevada. The purpose of this project is to develop a Geographic Information System (GIS) based water budget for Washoe Valley. With the use of satellite imagery and GIS processing, new estimates of mean-annual water-yield, open-water evaporation, evapotranspiration, ground-water discharge from phreatophytic vegetation, and domestic consumption are calculated. To calculate the water-budget, the Washoe Valley hydrographic area is subdivided into mountain-block and valley-floor areas where water budget components are identified and estimated on each landform, and then combined to calculate the overall water-budget for the hydrographic area. The distribution of precipitation was acquired from a precipitation map at 4 inch contour intervals, derived from local long-term precipitation measurements and vegetation patterns. Water-yield and runoff estimates were derived from geophysical tools, chloride-balance methods and simple least squares regression analysis. Estimates of domestic consumption, and evapotranspiration of precipitation and groundwater were based on vegetation distributions, and micrometeorological and regionalized remote sensing methods. When compared to water-budgets developed for Washoe Valley in 1967 and 1984, results from this study indicate more inflow from mountain-block areas, and more outflow from the valley-floor area. By integrating updated water-budget estimates in a GIS, this study provides spatially referenced information, which can be used in ground-water modeling efforts and provide a more refined planning tool for future water resource issues.