By Nancy E. Driver

Available from the U.S. Geological Survey, Branch of Information Services, Box 25286, Denver Federal Center, Denver, CO 80225, USGS Open-File Report 94–102, 2 p.

This document also is available in pdf format: OFR 94–102 (122 KB)
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In 1991, the U.S. Geological Survey, U.S. Department of the Interior, began a National Water-Quality Assessment (NAWQA) program. The long-term goals of the NAWQA program are to describe the status and trends in the quality of a large, representative part of the Nation's surface- and ground-water resources and to identify the major natural and human factors that affect the quality of these resources. In meeting these goals, the program will produce a wealth of water-quality information that will be useful to policy makers and managers at the National, State, and local levels.

The NAWQA program emphasis is on regional-scale water-quality problems. The program will not diminish the need for subregional and site-specific studies and monitoring presently designed and conducted by Federal, State, and local agencies to meet their individual needs. The NAWQA program, however, will provide a regional framework for conducting many of these activities and an understanding about regional and national water quality that cannot be acquired from individual, site-specific programs and studies.

Studies of 60 hydrologic systems that include parts of most major river basins and aquifer systems (study-area investigations) are the building blocks of the national assessment. The 60 study areas range in size from 1,000 square miles to more than 60,000 square miles and represent 60 to 70 percent of the Nation's water use and population served by public-water supplies. Twenty study-area investigations were started in 1991, 20 additional started in 1994, and 20 more are planned to start in 1997. The Upper Colorado River Basin in Colorado and Utah was selected as one of 20 study areas that began assessment activities in 1994.