Carson Valley Ground-Water Flow Model

Rapid growth and development in Carson Valley is causing concern over the continued availability of water resources to sustain such growth into the future. As growth continues, land presently used for agriculture will be urbanized and increases in pumping along with changes in the location and distribution of pumping also will take place. These changes may affect outflow of the Carson River and, in turn, water users depending on sustained river flow downstream from Carson Valley.

In the early 1980's, the USGS developed a numerical ground-water flow model of the ground-water and surface-water systems in Carson Valley. That model was considered to be preliminary and limited in its ability to predict drawdown from pumping in some parts of the valley. Since that time, much additional hydrologic data has been collected to refine and update estimates of water-budget components. Updated estimates need to be integrated into a refined numerical model so that water planners have a better tool for assessing potential effects of increased growth in Carson Valley.

Objectives

Develop a refined numerical ground-water flow model of Carson Valley, evaluate estimates of water-budget components, and estimate potential effects of change in land and water use.

Strategy and Approach

Work will extend over a period of four years and begin with compilation of data on ground-water pumping rates and distribution, streamflow diverted for irrigation, volumes of effluent imported to Carson Valley, ground-water level fluctuations, aquifer properties, and a detailed survey of the location and relative altitude of the surface-water distribution system in Carson Valley. A refined numerical model will be developed using this data and updated estimates of water-budget components. Model calibration will be accomplished by matching simulated and observed water-level fluctuations caused by changes in ground-water pumping and seasonal and annual changes in precipitation, and by matching the measured surface-water outflow of the Carson River. The model will be used to evaluate estimates of water-budget components and estimate the potential effects of land-use and water-use changes. Findings from this investigation will be reported in a USGS publication.

Relevance and Benefits

The proposed study is relevant to issue 1 of the Nevada Water Science Center Science Plan, refining and updating water budgets; issue 1 of the USGS Water Resources Discipline Strategic Directions, determining the effect of urbanization on water resources; and consistent with the goal of the USGS Strategic Plan of providing water-resource managers with accurate, reliable, and impartial scientific information. The work will benefit the cooperator and other water-resource agencies by providing information that can be used to assist in their decision-making process.

Publications

A complete list of USGS Nevada WSC Carson Valley publications: Carson Valley Bibliography (PDF)