Searchable database of data on more than 50 major river basins in the United States, including information about "water chemistry, hydrology, land use, stream habitat, and aquatic life." Searching also allows you to create maps that display the data geographically.

Specific chemicals (nutrients, pesticides, toxic chemicals, etc.), organisms and geographic terms are searchable. There are also reports concerning each of the ongoing river basin area studies from which this data is drawn.