The Environmental Protection Agency ( released a new version of its acclaimed watershed management program, making it easier to use and more readily available. “Better Assessment Science Integrating Point and Nonpoint Sources” (BASINS) is a multipurpose system that integrates environmental data, analytical tools, and modeling programs. BASINS is designed to help regions, states, and local agencies develop cost-effective approaches to watershed management and environmental protection. BASINS 4.0 is a valuable tool for watershed and water quality-based analyses, including developing total maximum daily load (TMDL) allocations.

Unlike earlier releases, BASINS 4.0 runs on nonproprietary, open source, free geographic information system (GIS) software, making the tool universally available to anyone interested in the system. Prior versions required users to purchase costly GIS software to run the BASINS system. Once installed on a personal computer, BASINS 4.0 gives users access to large amounts of point and nonpoint source data, which they can use to assess or predict flow and water quality for selected streams or entire watersheds.

For more information about BASINS 4.0, visit