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<br />
<br />FOREWORD
<br />
<br />The U.S. Geological Survey (USGS) is committed
<br />to serve the Nation with accurate and timely scientific
<br />information that helps enhance and protect the overall
<br />quality of life, and facilitates effective management
<br />of water, biological, energy, and mineral resources.
<br />(http://www.usgs.govl). Information on the quality
<br />of the Nation's water resources is of critical interest to
<br />the USGS because it is so integrally linked to the long-
<br />term availability of water that is clean and safe for
<br />drinking and recreation and that is suitable for indus-
<br />try, irrigation, and habitat for fish and wildlife. Esca-
<br />lating population growth and increasing demands for
<br />the multiple water uses make water availability, now
<br />measured in terms of quantity alld quality, even more
<br />critical to the long-term sustainability of our commu-
<br />nities and ecosystems.
<br />The USGS implemented the National Water-
<br />Quality Assessment (NA WQA) Program to support
<br />national, regional, and local information needs and
<br />decisions related to water-quality management and
<br />policy. (http://water.usgs.gov/nawqa). Shaped by
<br />and coordinated with ongoing efforts of other Federal,
<br />State, and local agencies, the NA WQA Program is
<br />designed to answer: What is the condition of our
<br />Nation's streams and ground water? How are the
<br />conditions changing over time? How do natural fea-
<br />tures and human activities affect the quality of streams
<br />and ground water, and where are those effects most
<br />pronounced? By combining information on water
<br />chemistry, physical characteristics, stream habitat, and
<br />aquatic life, the NAWQA Program aims to provide
<br />science-based insights for current and emerging water
<br />issues and priorities. NAWQA results can contribute to
<br />informed decisions that result in practical and effective
<br />water-resource management and strategies that protect
<br />and restore water quality.
<br />Since 1991, the NA WQA Program has imple-
<br />mented interdisciplinary assessments in more than 50
<br />of the Nation's most important river basins and aqui-
<br />fers, referred to as Study Units. (http://water.usgs.gov/
<br />nawqa/nawqamap.html). Collectively, these Study
<br />Units account for more than 60 percent of the overall
<br />water use and population served by public water
<br />supply, and are representative of the Nation's major
<br />hydrologic landscapes, priority ecological resources,
<br />and agricultural, urban, and natural sources of
<br />contamination.
<br />
<br />Each assessment is guided by a nationally consis-
<br />tent study design and methods of sampling and analy-
<br />sis. The assessments thereby build local knowledge
<br />about water-quality issues and trends in a particular
<br />stream or aquifer while providing an understanding
<br />of how and why water quality varies regionally and
<br />nationally. The consistent, multi-scale approach helps
<br />to determine if certain types of water-quality issues are
<br />isolated or pervasive, and allows direct comparisons of
<br />how human activities and natural processes affect
<br />water quality and ecological health in the Nation's
<br />diverse geographic and environmental settings. Com-
<br />prehensive assessments on pesticides, nutrients, vola-
<br />tile organic compounds, trace metals, and aquatic
<br />ecology are developed at the national scale through
<br />comparative analysis of the Study-Unit findings.
<br />(http://water.usgs.gov/nawqa/natsyn.html) .
<br />
<br />The USGS places high value on the communica-
<br />tion and dissemination of credible, timely, and relevant
<br />science so that the most recent and available knowl-
<br />edge about water resources can be applied in manage-
<br />ment and policy decisions. We hope this NAWQA
<br />publication will provide you the needed insights and
<br />information to meet your needs, and thereby foster
<br />increased awareness and involvement in the protection
<br />and restoration of our Nation's waters.
<br />
<br />The NA WQA Program recognizes that a national
<br />assessment by a single program cannot address all
<br />water-resource issues of interest. External coordina-
<br />tion at all levels is critical for a fully integrated
<br />understanding of watersheds and for cost-effective
<br />management, regulation, and conservation of our
<br />Nation's water resources. The Program, therefore,
<br />depends extensively on the advice, cooperation, and
<br />information from other Federal, State, interstate,
<br />Tribal, and local agencies, non-government organiza-
<br />tions, industry, academia, and other stakeholder
<br />groups. The assistance and suggestions of all are
<br />greatly appreciated.
<br />
<br />(2~ 1J1. /~
<br />
<br />Robert M. Hirsch
<br />Associate Director for Water
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<br />FOREWORD III
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