The Environmental Protection Agency (EPA) first created BASINS (Better Assessment Science Integrating Point and Nonpoint Sources) in 1996 as an aid to water resource planners concerned with water quality and watershed analyses. The strength of BASINS is its integration of "a geographic information system (GIS), national watershed data, and state-of-the-art environmental assessment and modeling tools." The updated version of the program, BASINS 2, can be downloaded from this site.