A product of the Clean Water Act, NRSA (National Rivers and Streams Assessment report) is a part of the 4 NARS (National Aquatic Resource Surveys) overlooked by the EPA and is completed in efforts by tribes, states, and other federal agencies in order to maintain and survey the quality of water across the country through a scientific approach to monitoring.
1.2 million perennial river and stream miles were surveyed to produce the below outcome, with the exception of fillets, which were only assessed in large river systems.