ORFULL

Thank you for your responses to the Major/Minor Drainage question, we are progressing very well.

I am now trying to determine the theory behind the ORFULL SWMM Configuration parameter.

I purchased the SWMM Workshop Notes which outline the various modules presently offered by SWMM. ORFULL was referred to in one of these modules, but I've been unable to find additional information about it. I would like to know how it works

any suggestions?
Jon Marshall
A-N West Consulting Engineers

Jon,

Extran makes an equivalent circular or rectangular conduit for an orifice for use during the simulation. The equivalent conduit is calculated by equating Manning's equation for full flow to the orifice equation at the full flow depth.

The purpose of the ORFULL keyword or fragment is to cap the flow through the orifice at the full flow orifice value. Since the orifice is now a pipe then more than full flow can go through the pipe when the pipe is surcharged.

Incidently, this keyword only applies to XP-SWMM32.

Regards,
Robert Dickinson
CAiCE Software