HEC-RAS Channel "forcing"

[DMcGrath]

I have a project where the first 6 or so cross sections have a parallel channel configuration. The channel with the higher invert is the "main" channel and the lower channel is where the overflow will go. Can I force the program to start the flow in the upper channel section, then overflow into the lower? As it runs now, it starts with the flow in the lower channel and the upper channel has zero flow. The upper channel is the designated discharge for a large pond, so I know the water will at least start there.

 

[francesca]

Yes, you can "force" the program to start in the upper channel and set it so that it only leaves that channel if the channel becomes submerged. There is an option in the cross-sections input box, under the Options menu, for setting ineffective flow areas. You want to set temporary ones, that disappear when the elevation is breached.

This link is probably more articulate.