The quality of our Nation’s waters : nutrients in the Nation’s streams and groundwater, 1992–2004

The USGS implemented the National Water-Quality Assessment (NAWQA) Program in 1991 to support national, regional, state, and local information needs and decisions related to water\xe2\x80\x91quality management and policy. The NAWQA Program is designed to answer: What is the quality of our Nation’s streams and groundwater? How are conditions changing over time? How do natural features and human activities affect the quality of streams and groundwater, and where are those effects most pronounced?

"This report is one of a series of publications, The Quality of Our Nation’s Waters, which describes major findings of the NAWQA Program on water-quality issues of regional and national concern. This report presents an assessment of the occurrence and distribution of nutrients in the Nation’s streams and groundwater based on water-quality data from about 500 streams and over 5,000 wells collected from 1992 through 2001. Other topics addressed include the relation of nutrient conditions to aquatic life in streams, changes in nutrient conditions from 1988 through 2004, and implications for future changes. Other reports in this series focus on additional water-quality constituents of concern such as pesticides and volatile organic compounds in streams and groundwater, the effects of contaminants and habitat on the condition of aquatic communities in streams, and on the quality of untreated water from private domestic and public supply wells. Each report builds toward a more comprehensive understanding of the quality of regional and national water resources.

"The information in this series is intended primarily for those interested or involved in resource management and protection, conservation, regulation, and policymaking at regional and national levels. In addition, the information is relevant to those at a local level who wish to know more about the general quality of streams and groundwater in areas near where they live and how that quality compares with other areas across the Nation" [Introduction]