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SWToolbox Software Information

USGS and EPA have combined their SWSTAT and DFLOW software programs into a new tool for the low flow analysis, the SWToolbox.

Overview and Help

The primary functions of SWToolbox are to conduct a n-day frequency analysis (most commonly used for computation of 7Q10) and to compute biologically-based design flows. Flow duration curves can also be computed. The software is designed to facilitate easy import of USGS NWIS streamflow data as well as user-defined text files.

SWToolbox is built on the EPA BASINS system. The SW Toolbox Documentation found under the Help menu provides information on the functionality of the software. Most of the information on use of the software is general and applies to all applications built on the BASINS platform.

Software and Manual Release

The user manual describes the functionality of the software and walks the user through an example session. It is available for viewing and download through the USGS publications warehouse:

The installation file below will install the software on Windows machines. Note that R must be installed on a user's system in order to access some functionality under the "Integrated Design Flow" workflow. The integration with R has been seamless on Windows 7 and 8 computers, but we have encountered problems with Windows 10 that we are still trying to resolve.


Updates and Feedback

If you would like to be notified of future updates to SWToolbox are released, please click here to leave your contact information

We are always looking for feedback on the SWToolbox software. If you encounter any problems, please let us know by sending an email to


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Page Last Modified: Thursday, 29-Mar-2018 10:31:20 EDT