This mapper provides results from the largest-ever assessment of water-quality changes in the Nation's streams and rivers. More than 185 million water-quality records from over 600 Federal, State, Tribal, and local organizations were screened as part of this assessment. Tracking changes in stream quality and investigating the reasons for these changes is crucial for informing management decisions to protect and sustain our valuable water resources. The mapper shows stream trends in water chemistry (nutrients, pesticides, sediment, carbon, and salinity) and aquatic ecology (fish, invertebrates, and algae) for four time periods: 1972-2012, 1982-2012, 1992-2012, and 2002-2012. Via usgs.gov