REGIONAL ASSESSMENT OF GROUND-WATER QUALITY IN PRINCIPAL AQUIFERS OF THE UNITED STATES

In the second decade (2001 - 2013) of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program, a major focus is on regional assessments of ground-water quality conditions and trends. The assessments will begin to evaluate those conditions and trends in 21 principal aquifers and will build on NAWQA findings from 1991 to 2001 in 51 local studies across the Nation. Regional assessments will complement and extend the local findings to fill critical gaps in our understanding of regional ground-water quality.

Each of the regional assessments will focus on water-quality issues of concern within a principal aquifer. Example issues of concern include (1) the occurrence of arsenic and deicing chemicals in the glacial deposits aquifers; (2) radon and uranium in the New England crystalline rocks and glacial deposits underlying the Northeast and upper Midwest; (3) salinity in aquifers underlying the Basin and Range and California Coastal Basins; (4) the occurrence of anthropogenic agricultural chemicals, such as fertilizers and pesticides, in domestic and public-supply wells in the Floridan, Northern Atlantic Coastal Plain, and the glacial deposits aquifers; and (5) studies that assess the effects on water quality of hydrologic alterations and controls—such as pumping, artificial recharge, and irrigation—in the High Plains, Hawaiian, Basin and Range, California Coastal Basin, and Central Valley aquifers.

Water-quality information in a regional context will be useful for regional monitoring councils, States, and localities in addressing priority water-quality and drinking-water issues in their areas. For example, regional-scale analyses, models, and other scientific tools will help with extrapolating findings to unmonitored, comparable areas in other parts of these regions.