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Water-Quality Changes in the Nation's Streams and Rivers

May 24, 2019

The trends 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.   

The mapper shows stream trends in water chemistry and aquatic ecology for four time periods from 1972-2012.