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Environmental Modeling Community of Practice

BASINS Version History

Version History

BASINS 4.5 Core

BASINS 4.5 Core is the first full BASINS release to be produced jointly by U.S. EPA National Exposure Research Laboratory (Computational Exposure Division) in Athens, Georgia and U.S. EPA Region 4 (Water Protection Division) in Atlanta, Georgia.

Version 4.5 Core of the Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) system is a maintenance release that builds on Version 4.1 and earlier versions of the system.  See the User’s Manuals for the earlier versions for the team involved in the production of those versions of the system.

BASINS 4.5 Core provides the following additional enhancements and features:

  • Complete replacement of all the data download libraries with the D4EM version of these libraries.  Data for Environmental Modeling, or D4EM, is a comprehensive set of tools that obtains and processes data to be used in mathematical environmental models. See for more information.
  • Updates the HUC8 layer of the ‘Build New Project’ national map to use the March 2017 update of the Watershed Boundary Dataset (WBD).
  • Provides access to both National Hydrography Dataset Plus (NHDPlus) version 1.0 and 2.1 through the data download tool.
  • Updates the National Land Cover Database (NLCD) data download options to include 2011 land use and impervious area data
  • Updates the North American Land Data Assimilation System (NLDAS) download to allow access to the full suite of meteorological constituents needed for watershed and in-stream models, as well as a new option to adjust time from UTC to the project time zone.
  • In BASINS 4.5 Core, all model plugins are installed separately from the BASINS 4.5 Core install. A list of EPA provided Model Plug-ins, along with a short description of its function, is provided in the manual. WinHSPF and WASP plug-ins will continue to be supported by U.S. EPA.  The third-party model Plug-ins (such as SWAT, GWLF, SWMM and others) will be made available for installation but will not be supported by U.S. EPA.

BASINS 4.1.1

  • BASINS 4.1.1 is a maintenance release of minor fixes.  It also includes updates to the URLs of downloaded datafiles. EPA went through a web server migration which means that data files are now available at a address. This release of BASINS may require the user to run BASINS As Administrator for downloads to work properly.


  • The current release of BASINS is built upon the latest stable release of the non-proprietary, open-source GIS MapWindow GIS (MapWindow website Exit). Along with the update to the underlying GIS platform, the BASINS automatic watershed delineation tools have been updated to use TauDEM version 5 from Utah State University.

    The major functionality of two utilities, GenScn and WDMUtil, have been incorporated into the BASINS user interface. BASINS 4.1 now includes DFLOW, a tool to estimate design stream flows for use in water quality studies. BASINS 4.1 is 64-bit and Windows 8 compatible.


  • The first version of BASINS to be primarily based on a non-proprietary, open-source GIS foundation. MapWindow GIS (MapWindow website Exit) is the lightweight open-source GIS upon which BASINS 4.0 is built. While not being dependent upon any proprietary GIS platform, the core of BASINS 4.0 is designed to complement and interoperate with enterprise and full-featured GIS systems. BASINS 4.0 can import and export projects from ArcView 3.x and ArcGIS 9.x. This interoperability allows users access to features available in these systems but not BASINS 4.0. Along with the change to the underlying GIS platform, the BASINS extensions were refactored as they were ported to the new system.

BASINS 3.0 and Earlier

Information about prior versions of BASINS is provided in the BASINS 4.1 User Manual(1 pg, 27 MB, 2013) .