New in GWRP

• Regional Ground-Water Studies
  • Ground-Water Availability in the United States
• Water Availability Pilot
  • Consumptive water use coefficients for Great Lakes Basin
• Ground Water & the Environment
  • Ground-Water Recharge in Southwestern US
• Methods & Modeling
  • SEAWAT v4--Simulation of 3D variable-density ground--water flow and transport
• Data & Information
  • Water-Level changes in aquifers of the Atlantic Coastal Plain, predevelopment to 2000

USGS in Your State

USGS Water Science Centers are located in each state.

Regional Ground-Water Evaluations

Ground-Water Availability of Selected Principal Aquifers

During the past 50 years, depletion of ground water has spread from small, isolated pockets to large areas of the country, as ground-water 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 ground-water resources. Assessing the current state of the ground-water flow systems in the highest stressed systems would be invaluable tools for assessing ground-water 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 ground-water 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 ground-water availability in areas of critical importance. These assessments will document the effects of human activities on water levels, ground-water storage, and discharge to streams and other surface-water bodies, and evaluate the adequacy of data networks to assess impacts at a regional scale.