BASINS is a free tool developed and maintained by US EPA.
Learn more at the EPA website.
Better Assessment Science Integrating point and Nonpoint Sources (BASINS) is a multipurpose environmental analysis system and has been made freely available by its developer, the US EPA. BASINS provides a convenient framework for integrating modeling tools and environmental spatial and tabular data into a geographic information system (GIS) interface. From the BASINS interface, you can automatically download vital data such as DEMs, hydrography, land use, meteorological data, monitoring data, and soil maps from EPA, USGS.
DSI has recently developed a plugin for BASINS that allows users to generate the grid and build an Environmental Fluid Dynamics Code Plus (EFDC+) model directly from within the BASINS interface.
The EEMS plugin for BASINS provides an important link between watershed models and receiving water hydrodynamic models. Users can go from extensive basin-scale studies to more in-depth analyses of particular water bodies and the impact of pollutant loading. This plugin is the first step in what we envision to be greater integration between hydrologic and hydrodynamic models, facilitating improved data exchange and ease of use for those seeking solutions to complex environmental questions. Read more on our blog.
Guidance on how to use this plugin and a video demonstration from one of the EEMS-BASINS plugin development team.