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Home > 125th > Articles > USGS Science -- Yesterday, Today, and Tomorrow | September 22, 2008 | |||||
Monitoring and Assessing our Nation's Water Quality By Timothy L. Miller, Pixie A. Hamilton, and Donna N. Myers All of life depends on water, and all of us are citizens of a watershed. Our activities and the ways we use our water resources and the land adjacent to the water affect the quality of our drinking water, our recreational opportunities, and the health and diversity of aquatic plants and animals. The quality of our water--from the nearby stream to the large river system--can be protected and enhanced by collecting timely and relevant information about water-quality conditions and by responding to that information. The USGS has monitored and assessed our Nation's streams and ground water since the late 19th century. Today, USGS provides information on many water-quality issues, such as the suitability of water used for drinking and irrigation and the health of our aquatic ecosystems. USGS describes the general health of water resources, as well as current and emerging water issues and priorities, all of which contribute to practical and effective water-resource management and strategies that protect and restore water quality. The findings are used by decision makers at all levels--including, for example, managers and planners in localities, States, Tribes, and Federal agencies, such as the National Park Service, Fish and Wildlife Service, Bureau of Reclamation, and U.S. Environmental Protection Agency; policy makers in Congress and non-governmental organizations; researchers in industry, academia, and consulting; and the general public. Major water-quality programs (listed below, along with corresponding Web sites) touch many parts of the Nation, from Alaska and Hawaii to the coasts of Florida and Maine. For example, in partnership with the National Park Service since 1998, USGS has addressed water-quality issues in 64 national parks in 33 States--helping to ensure safer swimming beaches and drinking water, healthy stream habitats and aquatic life, adequate baseline monitoring, and assessment of contaminants in natural areas, such as in snow-packs and high-altitude lakes. Through its National Stream Quality Accounting Network (NASQAN), USGS operates 32 stations to measure amounts of sediment and chemicals in five of the Nation's largest rivers (Mississippi, Columbia, Colorado, Rio Grande, and Yukon). Data from the stations aid in managing, using, and protecting these major, heavily regulated rivers that flow across interstate and international boundaries. USGS also monitors 36 relatively small streams draining natural basins that have been minimally altered by human activities (referred to as the Hydrologic Benchmark Network). These data also are used to track subtle effects from atmospheric deposition and climate change. At the other end of the spectrum, the USGS Toxic Substances Hydrology Program focuses on widespread contamination that poses significant risk to human health and the environment, including effects of mercury on aquatic ecosystems and the recent discovery of everyday chemicals, such as pharmaceuticals, personal care products, and hormones, in our waters. Identification of these additional chemicals in the environment also leads to improved understanding of how water systems function.
As part of the National Water-Quality Assessment (NAWQA) Program, begun in 1991, USGS assesses water quality in 51 major river basins and aquifers across the Nation. Collectively, the studies advance our understanding of the quality of the Nation's waters and enables us to determine whether it is getting better or worse over time. Overall, USGS water-quality monitoring, assessments, and research indicate that the Nation's waters generally are suitable for irrigation, drinking water supply, and other home and recreational use. Major challenges remain, however, in protecting water resources and aquatic ecosystems from nonpoint sources of pesticides, nutrients, metals, petroleum-based compounds, industrial and household solvents, and naturally occurring pollutants that continue to enter our aquifers and waterways in every basin. A primary objective in USGS water-quality studies is to identify natural and human-related factors that affect water-quality conditions and transport of contaminants to ground water and over the land. For example, no longer is it appropriate to think that nonpoint-source contamination is exclusively associated with agriculture. Nonpoint sources in urban areas ("urban" primarily refers to residential and commercial development over the last 50 years), which cover less than 5 percent of land in the continental United States, have not typically been considered to be important contaminant sources compared to agricultural areas, which cover more than 50 percent of the United States. The studies, however, have documented elevated trace elements, as well as nutrients, pesticides, and volatile organic compounds commonly used around homes, gardens, and in commercial and public areas in urban streams and ground water. Improvements in water quality therefore will depend upon effective management of nonpoint sources in our urban centers along with agricultural areas, in addition to continued control of our "point" discharges of sewage and industrial wastes. USGS studies also show that water-quality conditions are highly variable, differing from season to season and from watershed to watershed. Pollution levels and degradation of ecosystems vary because of differences in chemical use, land-management practices, watershed development, population, and natural features, such as soils, geology, hydrology, and climate. Even among seemingly similar land uses and sources of contamination, streams and ground water in different geographic areas show different vulnerability to contamination. This information allows decision makers to design more effective strategies for improving water quality in specific geographic areas. Examples of USGS findings on water quality across the Nation include the following: What's Used Is What's Found
Lay of the Land Matters--Transport of chemicals and vulnerability depends on natural features and land-use practices
The Big Picture--Interactions among water, air, and aquatic life
Looking Down the Road at Trends
USGS water-quality data are readily available. The large USGS database on water-quality conditions is publicly available and can be readily accessed via the Internet (http://water.usgs.gov/nwis). It includes chemical data from rivers, streams, lakes, springs, and ground water from more than 335,000 sites. Selected field measurements, such as pH, temperature, and specific conductance, are available in real-time (updated at intervals of 4 hours or less) at more than 800 USGS sites. Access online maps, data, and reports on USGS water-quality programs: |
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