National Water Quality Program
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The National Water Quality Program provides an understanding of water-quality conditions; whether conditions are getting better or worse over time; and how natural features and human activities affect those conditions.
Featured Study: Insights into changes in chloride in streams
A joint USEPA-USGS study finds that integrating water-quality sampling approaches can provide insight into changing chloride concentrations in U.S. streams and rivers.
Learn moreFeatured Study: Potential lead solubility in groundwater
About one-third of more than 8,300 wells tested across the U.S. had groundwater with chemical characteristics that could cause lead, if present in plumbing, to leach into tap water at levels above the EPA Action Level.
Learn MoreNews
New release: User-friendly Point-Source Load Estimation Tool (PSLoadEsT)
Do you need consistent and reliable data for nutrient concentrations released by point-source dischargers? The USGS has developed a new approach for developing typical pollutant concentrations (TPCs) in the absence of measured total nitrogen (TN) or total phosphorus (TP) concentration data and a new tool, the Point-Source Load Estimation Tool (...
Estimates of areal extent of U.S. parking lots now available
Parking lots may be a significant source of pollution, but up until now there has been no quantitative estimate of the areal extent of parking lots in the U.S.
Sampling design brings insights to changing stream quality
How does the choice of sampling approach affect our perception of whether water quality in streams and rivers has changed over time? A new joint U.S....
Publications
Assessing water-quality changes in U.S. rivers at multiple geographic scales using results from probabilistic and targeted monitoring
Two commonly used approaches for water quality monitoring are probabilistic and targeted. In a probabilistic approach like the US Environmental Protection Agency’s National Rivers and Streams Assessment, monitoring sites are selected using a statistically representative approach. In a targeted approach like that used by many monitoring...
Sprague, Lori A.; Mitchell, Richard M; Pollard, Amina I.; Falcone, James A.
An exploratory Bayesian network for estimating the magnitudes and uncertainties of selected water-quality parameters at streamgage 03374100 White River at Hazleton, Indiana, from partially observed data
An exploratory discrete Bayesian network (BN) was developed to assess the potential of this type of model for estimating the magnitudes and uncertainties of an arbitrary subset of unmeasured water-quality parameters given the measured complement of parameters historically measured at a U.S. Geological Survey streamgage. Water-quality data for 27...
Holtschlag, David J.
Understanding the influence of nutrients on stream ecosystems in agricultural landscapes
Sustaining the quality of the Nation’s water resources and the health of our diverse ecosystems depends on the availability of sound water-resources data and information to develop effective, science-based policies. Effective management of water resources also brings more certainty and efficiency to important economic sectors. Taken together,...
Munn, Mark D.; Frey, Jeffrey W.; Tesoriero, Anthony J.; Black, Robert W.; Duff, John H.; Lee, Kathy E.; Maret, Terry R.; Mebane, Christopher A.; Waite, Ian R.; Zelt, Ronald B.