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In 1991, the U.S. Geological Survey began a 4-year transition from a pilot National Water-Quality Assessment (NAWQA) program to a full-scale program. The design concepts to be implemented in the full-scale program are based in part on the pilot program that began in 1986. 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 surfaceand ground-water resources and to provide a sound, scientific understanding of the primary natural and human factors affecting 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.
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Leahy et al. (1991) studied this question.
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