Excerpt
Water contamination from point sources such as discharges of sewage and industrial waste has been substantially reduced thanks to the Clean Water Act of 1972. Despite the gains, 40 percent of our waters are still too contaminated for basic uses such as swimming and fishing.
The overwhelming majority of waterquality problems we face today result from diffuse “nonpoint” sources of pollution from agricultural land, urban development, forest harvesting and the atmosphere. The pollution they deliver varies hour to hour and season to season malung it difficult to quantify the sources. Moreover, contaminants now include hundreds of synthetic organic compounds like pesticides and volatile organics in solvents and gasoline, microbial and viral contamination as well as pharmaceuticals and hormones. The complex and demanding steps necessary to pinpoint and quantify these are just the first steps to effective management.
In 1991, the U.S. Geological Survey (USGS) launched a comprehensive water quahty program called National Water-Quality Assessment (NAWQA). This program is a primary source for long term, nationwide information on the quality of streams, groundwater, and aquatic ecosystems. In more than 50 major river basins and aquifers across the nation (See map), USGS scientists collect and assess information on …
Footnotes
Pixle A. Hamilton is a staff hydrologist and communications specialist for the National Water-Quality Assessment Program.
Timothy L. Miller is chief of the National Water-Quality Assessment Program.
- Copyright 2002 by the Soil and Water Conservation Society