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Last Updated: Wednesday, February 7, 2018 10:06 AM

Basin Sizer

Detention Basin  

Download Basin Sizer Version1.47 (18.8 MB)

The Basin Sizer Program allows users to find information useful for sizing stormwater basins in California

New Features in Version 1.4

California Stormwater Quality Association (CASQA) Methods - Three approaches to sizing BMPs from CASQA's 2003 California Stormwater BMP Handbook, New Development and Redevelopment have been added.

Updated Numbers - Rainfall data through 2005 have been used to recalculate water quality volumes and flows for all methods.

Improved Help - All of the BMP sizing methods now have easily accessible help and procedures, just click on the boxes with question marks to the right of the methods.

New User Interface - The results of the Maximized Volume Method are no longer presented as a grid of numbers. The user can now select drawdown times and runoff coefficients from dropdown boxes. This makes it easier to understand the method and allows users to input any runoff coefficient between 0.30 and 1.

Printing - The results of Basin Sizer can now be sent to a printer.

Changes from 1.45 to 1.47

Updated the Caltrans tab to use the 85th percentile 24-hr storm and moved the other methods to the historic tab.

To install, unzip the file and run setup.


Division of Environmental Analysis, Stormwater Unit
California Department of Transportation
P.O. Box 942874, MS-27
Sacramento, CA 94274-0001
Email: Division of Environmental Analysis, Stormwater Unit