Preliminary estimates of spatially distributed net infiltration and recharge for the Death Valley region, Nevada-California
A three-dimensional ground-water flow model has been developed to evaluate the Death Valley regional flow system, which includes ground water beneath the Nevada Test Site. Estimates of spatially distributed net infiltration and recharge are needed to define upper boundary conditions. This study presents a preliminary application of a conceptual and numerical model of net infiltration. The model was developed in studies at Yucca Mountain, Nevada, which is located in the approximate center of the Death Valley ground-water flow system. The conceptual model describes the effects of precipitation, runoff, evapotranspiration, and redistribution of water in the shallow unsaturated zone on predicted rates of net infiltration; precipitation and soil depth are the two most significant variables. The conceptual model was tested using a preliminary numerical model based on energy- and water-balance calculations. Daily precipitation for 1980 through 1995, averaging 202 millimeters per year over the 39,556 square kilometers area of the ground-water flow model, was input to the numerical model to simulate net infiltration ranging from zero for a soil thickness greater than 6 meters to over 350 millimeters per year for thin soils at high elevations in the Spring Mountains overlying permeable bedrock. Estimated average net infiltration over the entire ground-water flow model domain is 7.8 millimeters per year. To evaluate the application of the net-infiltration model developed on a local scale at Yucca Mountain, to net-infiltration estimates representing the magnitude and distribution of recharge on a regional scale, the net-infiltration results were compared with recharge estimates obtained using empirical methods. Comparison of model results with previous estimates of basinwide recharge suggests that the net-infiltration estimates obtained using this model may overestimate recharge because of uncertainty in modeled precipitation, bedrock permeability, and soil properties for locations such as the Spring Mountains. Although this model is preliminary and uncalibrated, it provides a first approximation of the spatial distribution of net infiltration for the Death Valley region under current climatic conditions.
- Research Organization:
- United States Geological Survey - Nevada, Las Vegas, NV (US)
- Sponsoring Organization:
- USDOE Nevada Operations Office (NVOO) (US)
- DOE Contract Number:
- AI08-96NV11967
- OSTI ID:
- 797779
- Report Number(s):
- USGS WRIR 02-4010; TRN: US0201861
- Resource Relation:
- Other Information: PBD: 18 Jul 2002
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
BOUNDARY CONDITIONS
DISTRIBUTION
FLOW MODELS
GROUND WATER
MOUNTAINS
NEVADA TEST SITE
PERMEABILITY
PRECIPITATION
RUNOFF
SOILS
SPATIAL DISTRIBUTION
THICKNESS
YUCCA MOUNTAIN
HYDROLOGY
HYDROGEOLOGY
GROUNDWATER
FLOW MODEL
DEATH VALLEY
NEVADA
CALIFORNIA
INFILTRATION
RECHARGE
UNSATURATED ZONE