Strategy to Assess the Nation's Ground-Water Availability

The report, "Ground-Water Availability in the United States" examines what is known about the Nation's ground-water availability and outlines a strategy for future national and regional studies that would provide information to help state and local agencies make informed water-availability decisions.

The approach outlined in the report is designed to provide useful regional information for State and local agencies who manage ground-water resources, while providing the building blocks for a national assessment. The report places the regional studies by the USGS Ground-Water Resources Program as a long-term effort to understand ground-water availability in major aquifers across the Nation. The report contains information about 30 regional principal aquifers and five case studies to illustrate the diversity of water-availability issues. The report is written for a wide audience interested or involved in the management, protection, and sustainable use of the Nation's water resources.

Ground water, a hidden resource found below the surface of the Earth, is among the Nation's most important natural resources. Extensive use of ground-water resources and other effects of pumping has led to concerns about the future availability of ground water to meet domestic, agricultural, industrial, and environmental needs.

Determining ground-water availability is a complex process. Issues affecting ground-water vary from location to location and commonly require analysis in the context of ground-water flow systems to achieve a meaningful perspective. Even if water resources are abundant regionally, heavy water use in centralized areas can create local stresses. As water-related problems evolve in complex ways, an up-to-date and comprehensive evaluation of ground-water resources that builds on the foundation of previous studies is needed to meet society's ever-changing water demands.

This report is an outgrowth of a pilot study, National Assessment of Water Avail­ability and Use, that began in 2005 at the request of Congress. The report also builds on regional ground-water availability studies recently undertaken as part of the USGS Ground-Water Resources Program. The approach to national ground-water assessment is a key element of the water census of the United States, which has been proposed as part of the proposed Federal science strategy to meet nationwide water chal­lenges by the National Science and Technology Council Subcommittee on Water Availability and Quality.