In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project of the National Water-Quality Program. One of the major goals of the NAWQA project is to determine how water-quality conditions change over time. To support that goal, long-term consistent and comparable monitoring has been conducted on streams and rivers throughout the Nation. Outside of the NAWQA project, the USGS and other Federal, State, and local agencies also have collected long-term water-quality data to support their own assessments of changing water-quality conditions. Data from these multiple sources have been combined to support one of the most comprehensive assessments conducted to date of water-quality trends in the United States. Ultimately, these data will provide insight into how natural features and human activities have contributed to water-quality changes over time in Nations streams and rivers. This USGS data release contains all of the input and output files necessary to reproduce the results of the Seasonal Kendall trend tests described in the associated U.S. Geological Survey Scientific Investigations Report (http://dx.doi.org/10.3133/sir20175006). Data preparation for input to the model is also fully described in the above-mentioned report.
|Title||Water-quality and streamflow datasets used in Seasonal Kendall trend tests for the Nations rivers and streams, 1972-2012|
|Authors||Taylor J. Mills, Lori A. Sprague, Jenny C. Murphy, Gretchen P. Oelsner, Henry M. Johnson, James A. Falcone, Edward G. Stets|
|Product Type||Data Release|
|Record Source||USGS Digital Object Identifier Catalog|
|USGS Organization||Office of Planning and Programming|
Water-quality trends in the nation’s rivers and streams, 1972–2012—Data preparation, statistical methods, and trend results
Water-quality trends in the nation’s rivers and streams, 1972–2012—Data preparation, statistical methods, and trend resultsSince passage of the Clean Water Act in 1972, Federal, State, and local governments have invested billions of dollars to reduce pollution entering rivers and streams. To understand the return on these investments and to effectively manage and protect the Nation’s water resources in the future, we need to know how and why water quality has been changing over time. As part of the National Water-Qual