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Groundwater Availability Detailed in California's Central Valley

USGS Groundwater Watch

USGS maintains a network of active wells to provide basic statistics about groundwater levels.

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Regional Groundwater Evaluations

Groundwater Availability of Selected Principal Aquifers

During the past 50 years, depletion of groundwater has spread from small, isolated pockets to large areas of the country, as groundwater use has intensified. The consequences of large-scale removal of water from storage are becoming increasingly evident. These consequences include land subsidence; loss of springs, streams, wetlands, and associated habitat; and degradation of water quality. These documented results in combination with recent droughts have emphasized the need for updated status on the availability of the Nation's groundwater resources. Assessing the current state of the groundwater flow systems in the highest stressed systems would be invaluable tools for assessing groundwater availability under present conditions.

To that end, three principal aquifers geographically distributed across the United States were selected for study in 2004: Atlantic Coastal Plain aquifers in North and South Carolina, Denver Basin aquifer in Colorado, and the Central Valley aquifer in California. In fiscal year 2006, a study of the Mississippi Embayment aquifers in parts of Arkansas, Louisiana, Mississippi, and Tennessee began. Information about these aquifers is critically needed to support better management of groundwater resources in these areas with chronic water-supply issues. The GWRP is taking advantage of the quantitative work previously conducted by the RASA Program to provide updated quantitative assessments of groundwater availability in areas of critical importance. These assessments will document the effects of human activities on water levels, groundwater storage, and discharge to streams and other surface-water bodies, and evaluate the adequacy of data networks to assess impacts at a regional scale.