The concept of Flow Duration control is relatively new, and designing these facilities requires the use of a continuous simulation hydrologic model to characterize the flow frequencies associated with small high frequency rainfall events. This mitigates adverse effects of hydrologic alterations due to urban development and redevelopment.
To facilitate this design approach, SCVURPPP, ACCWP and SMCWPPP have jointly sponsored development of the BAHM - a user-friendly software tool for automated modeling and facility sizing, adapted from the Western Washington Hydrology Model (WWHM).WWHM was first developed in 2001 to support the Flow Duration design requirements in the Stormwater Management Manual for Western Washington.
The BAHM incorporates local rainfall and climate data as well as calibrated model parameters for an internal modeling engine using HSPF. The software's input and reporting interfaces allow both project designers and municipal reviewers to check designs without previous experience with simulation modeling.
New April 2014: BAHM2013
BAHM2013 gives the user greater modeling flexibility, options, and accuracy than were available in the original BAHM (dated 2007). BAHM2013 includes modeling elements that more accurately model stormwater LID (low impact development) facilities compared to some simplified approaches used in the original BAHM.
Windows 2000/XP/Vista/7/8 with 200 MB uncompressed hard drive space
Internet access (only required for downloading BAHM2013, not required for executing
Pentium 3 or faster processor (desirable)
Color monitor (desirable)
Additional installation information
Please note the BAHM and BAHM2013 cannot be run from a network. The software can be loaded and run locally on computers that are networked.