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Our surface water, groundwater, and aquatic ecosystems are priceless resources, used by people across the Nation for drinking, irrigation, industry, and recreation. The National Water-Quality Assessment (NAWQA) Project is a leading source of scientific data and knowledge for development of science-based policies and management strategies to improve and protect our water resources.
A new USGS study reports that 16 dissolved pesticides were consistently detected in small streams in 16 urban centers across five regions of the United States.
A new USGS study of pesticides in U.S. rivers and streams reports that, on average, 17 pesticides were detected at least once at the 74 river and stream sites sampled 12 to 24 times per year during 2013–2017.
Looking for data? Maps? Use these links to quickly access some of the most frequently visited USGS web pages on water quality.
In 1991, Congress established the National Water-Quality Assessment (NAWQA) Project to address where, when, why, and how the Nation's water quality has changed, or is likely to change in the future, in response to human activities and natural factors. Since then, NAWQA has produced scientific data and knowledge that is used by national, regional, state, and local agencies to develop science-based policies and management strategies to improve and protect water resources used for drinking water, recreation, irrigation, energy development, and ecosystem needs. A prominent feature of NAWQA is the development of long-term consistent and comparable information on streams, rivers, ground water, and aquatic systems. The NAWQA Project is designed to answer these questions:
SURFACE WATER AND ECOLOGY
Water Quality and Ecology of Small Streams (RSQA)
The Regional Stream Quality Assessment (RSQA) is studying the relations between stressors (chemical and physical) and stream ecology (fish, algae, and aquatic invertebrates) at small streams in five large regions of the United States. Users can access an online mapping tool to compare water quality at small streams across a region, see scorecards that summarize stream health at each stream site, and download data for hundreds of chemical compounds.
Water Quality in the Nation's Streams and Rivers: Current Conditions and Long-Term Trends
Knowing the current water-quality conditions of our rivers and streams and where those conditions have improved or deteriorated is critical information for resource managers and the public. An online water-quality tracking tool shows graphs of pesticides, nutrients, and sediment in streams, and users can download data for a streams and rivers across the country; the tool is updated annually. The online water-quality trends mapping tool allows users to visualize trends in water chemistry (nutrients, pesticides, sediment, carbon, and salinity) and aquatic ecology (fish, invertebrates, and algae).
SPARROW modeling: Estimating nutrient, sediment, and dissolved solids transport
SPARROW (SPAtially Referenced Regression On Watershed attributes) models estimate the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources. Users can explore relations between human activities, natural processes, and contaminant transport using interactive mappers.
Groundwater Quality: Current Conditions and Changes Through Time
Scientists are characterizing groundwater quality in principal aquifers, the primary source of the Nation's groundwater used for drinking. Concentrations of inorganic constituents, such as arsenic and nitrate, and organic constituents, such as pesticides and volatile organic compounds, are compared to benchmarks established for the protection of human health. Users can access an online tool to see how concentrations of pesticides, nutrients, metals, and organic contaminants in groundwater are changing during decadal periods across the Nation, and see in real time how chemical properties of groundwater at some sites are fluctuating.
Groundwater Quality: Predictions for Unmonitored Areas
Groundwater hydrologists are developing statistical models that predict where a contaminant is likely to occur in groundwater and at what concentration. These models extrapolate groundwater quality in areas and at depths where groundwater has not yet been sampled. Users can see predicted contaminant concentrations in map view, and—for some aquifers—in 3-D.
SURFACE WATER/GROUNDWATER INTERACTION
Surface water and groundwater are intimately connected and are constantly interacting. The Integrated Watershed Studies team is quantifying how water and chemicals move between the landscape, streams and rivers, and groundwater. Learn how the quantity and quality of surface water and groundwater are likely to change in response to changes in climate, land use, and best management practices.
From 1991-2001, the NAWQA Project conducted interdisciplinary assessments, including water chemistry, hydrology, land use, stream habitat, and aquatic life, and established a baseline understanding of water-quality conditions in 51 of the Nation's river basins and aquifers, referred to as Study Units.
From 2001-2012, NAWQA focused on specific water-quality topics of national interest, such as pesticides, nutrients, and aquatic ecology, as well as continuing to monitor and assess 42 of the Study Units.
► Learn about the first two decades of NAWQA research and access information and publications about the quality of the Nation's surface-water and groundwater resources.
Find methods used by NAWQA to assesses the current quality of our surface water and groundwater.
► Documentation on water-quality sample collection methods developed by NAWQA.
RELATIONS BETWEEN LAND USE AND WATER QUALITY
Urban Land Use and Water Quality
CONTAMINANTS IN WATER
Arsenic and Drinking Water
Chloride, salinity, and dissolved solids
Emerging contaminants (including pharmaceuticals and hormones)
Metals and Other Trace Elements
Nutrients and Eutrophication
National Atmospheric Deposition Program (NADP)
Pesticides and Water Quality
Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health
Volatile organic compounds (VOCs) (including MTBE)
DRINKING WATER ISSUES
Domestic (private) supply wells
Drinking-water taste and odor
Water-Quality Benchmarks for Contaminants
Drinking Water and Source Water Research
RELATIONS TO AQUATIC LIFE
NWQP Research on Harmful Algal Blooms (HABs)
TRENDS IN WATER QUALITY
Water-quality trends from lake sediment cores
► Confused by some of the water-quality terms? Find the definitions and explanations you're looking for in the Water-Quality Glossary.
Learn more about some of the research associated with the National Water Quality Assessment project.
Web applications and downloadable data related to NAWQA water-quality research.
The NAWQA project publishes reports that describe water-quality and ecological conditions; whether conditions are changing over time; and how natural features and human activities affect these conditions.
The most recent publications and selected national-scale reports are listed here.
Interactive mappers and web applications related to NAWQA water-quality research.
Isotopes of mercury in fish can indicate the source of that mercury, reports a new study from the USGS Regional Stream Quality Assessment.