In 1991, the U.S. Geological Survey (USGS), U.S. Department of the Interior, began a full-scale National Water-Quality Assessment (NAWQA) program. The objectives of the NAWQA program are to describe the present and future water quality of large, representative parts of the United States's surface- and ground-water resources and to identify the primary natural and man-made factors that affect the quality of these resources. The final product of the program will be information that may be used by water-resource policy makers and managers at national, State, and local levels.
The NAWQA program encompasses 60 study units. These units are delineated by hydrologic systems that include parts of most of the Nation's major river basins and aquifer systems. Study units range in size from 1,000 mi2 (square miles) to more than 60,000 mi2 and represent 60 to 70 percent of the Nation's water use and population served by public water supplies. The first group of 20 study-unit investigations began in 1991. A second group of 20 study-unit investigations began in 1994, which includes the Northern New England Basins study unit.
