A new U.S. Geological Survey (USGS) interactive map provides a comprehensive, long-term look at changes in the quality of U.S. rivers and streams over the last four decades.

For the first time, monitoring data collected by the USGS and 73 other organizations at almost 1,400 sites have been combined to provide a nationwide look at changes in the quality of U.S. rivers and streams between the 1972 passage of the Clean Water Act and 2012.