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Puget Sound Basin NAWQA Study
U.S. Geological Survey
934 Broadway,
Suite 300
Tacoma, WA 98402

(253) 552-1600
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Puget Sound Basin NAWQA

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Map of study areaThe Puget Sound Basin (PUGT) study unit of the National Water Quality Assessment (NAWQA) program encompasses a 13,700-square-mile area that drains to Puget Sound and adjacent marine waters. Included in this region are all or part of 13 counties in western Washington, as well as the headwaters of the Skagit River and part of the Nooksack River in British Columbia, Canada. The Puget Sound Basin contains surface- and ground-water resources of economic and ecological importance. These resources provide water for a large and expanding population, hydroelectric power, recreational opportunities, and an ecosystem that supports an economically important fishery. Surface and ground waters also have the potential to transport nutrients and contaminants to the Puget Sound.

Water-quality issues in the region’s surface waters include loss of aquatic habitat through forestry, agricultural, and land-development practices; contamination of streams and marine waters by point-source discharges and storm washoff of metals, pesticides, and petroleum products from urban and suburban areas; and nutrient enrichment of lakes and Puget Sound embayments. In ground waters, the important issues include contamination by pesticides and other synthetic organic chemicals in agricultural, urban, and industrial areas; elevated nitrate concentrations in rural and agricultural areas; and protecting ground-water quality to provide safe drinking-water supplies.

Images of StreamsWHAT IS NAWQA?

The U.S. Geological Survey’s National Water Quality Assessment (NAWQA) program provides an understanding of water-quality conditions and how those conditions might vary locally, regionally, and nationally; whether conditions are getting better or worse over time; and how natural features and human activities affect those conditions. The program is designed to take a long-term view of water-quality issues and therefore, study-unit assessments are designed as multiphase water-quality investigations over several years in order to meet this long-term study objective. Click here to read more about the NAWQA Program.

Cycle I

The first cycle of the Puget Sound Basin study-unit assessment was carried out from 1994 – 2003. During those 10 years, the study team identified water-quality issues; accumulated and evaluated existing, historical water-quality data; collected surface- and ground-water quality data; and conducted aquatic ecological surveys. Data analyses and publications of findings were completed in 1999 and 2000. In 2001, the assessment shifted into a low-level data-collection phase with the purpose of tracking long-term trends and identifying emerging water-quality issues prior to beginning a second high-intensity phase in 2004.

Planning, and analysis of existing data
Intensive data collection and analysis
Completion of primary reports
Low-level assessment activities

For a summary of Cycle I studies on the quality of ground water and surface water, and studies of aquatic ecosystems, see Circular 1216.

Puget Sound - Tacoma Tide Flats

Cycle II

Water-year 2004 marked the beginning of the second cycle of intensive water-quality assessments in the Puget Sound Basin. The intent of NAWQA’s second decade of study is to build on initial water-quality assessments and increase investigations of long-term trends and factors affecting water quality. Cycle II efforts in surface water of the Puget Sound Basin focus on urbanization effects on stream ecosystems in the Puget Lowland ecoregion. Data from 21 streams will be analyzed to determine the magnitude and pattern of hydrologic, chemical, and biological community responses to urbanization and if thresholds exist at which stream ecosystems degrade more rapidly with varying levels of urbanization. In ground water, efforts focus on a second round of data collection from wells in the urban and agricultural land-use study areas. After a 10-year period, approximately 20 wells in the 2 study areas will be re-sampled to build on data for long-term trend analyses.

Planning and establishment of study sites
Intensive data collection and analysis
Completion of reports
Low-level assessment activities

For a synopsis of what was learned about streams during Cycle I and future plans for studies during Cycle II, see: Quality of Streamwater in the Puget Sound Basin—A Decade of Study and Beyond

Puget Sound Highlights

NAWQA Highlights

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