In the most recent data available, the Environmental Protection Agency’s (EPA) National Rivers and Streams Assessment 2008-2009 classifies 55% of U.S. river and stream miles as being in poor condition for aquatic life and gives another 22% a “fair” rating. The major culprits: (1) excessive levels of the fertilizers nitrogen and phosphorous, (2) high levels of bacteria and mercury, (3) decreased vegetation coverage, and (4) increased human disturbance.
Rivers and streams in the West were significantly more likely to be classified as healthy (42%) than were those in the East and Plains regions (17% and 16%, respectively).
The EPA says the overall findings demonstrate the importance of addressing the sources of these stressors, including storm water runoff from urban areas, agricultural practices, and wastewater treatment.
