Wet Pond

[Saital]

I am working on a residential subdivision project in the City of Durham, North Carolina, with a total site area of approximately 20 acres. The project includes a wet detention pond with a forebay, and I need to model this stormwater facility.

Which software is most suitable for this purpose: HydroCAD, Hydrology Studio, EPA SWMM, or HEC-HMS?

Additionally, I would like to understand how to properly model the forebay in each of these software packages, including the recommended approach and any applicable best practices.

 

[psmart]

For HydroCAD: The easiest solution is to ignore the depressed storage the forebay and model as a single pond. This avoids having to deal with the tailwater effects, and is trivial to setup. If you want to model the depressed storage more precisely:
1) Use separate ponds for the forebay and main storage.
2) Define storage for each pond up to the top of the embankment, based on an imaginary wall between the two ponds.
3) Use a weir outlet from the forebay to the main storage.
4) Use DSI routing to handle the tailwater.
5) Reduce the dt to 0.01 hours (or less) as required to get a stable routing.