Drywells?

[acsimpson]

Is there a way to place drywells as an outflow structure of a pond? Here we are required to place the rim of drywells 0.5' above the bottom of pond elevation.

 

[psmart]

I'm not clear about your configuration. Does the elevated rim prevent flow into the drywell until the pond exceeds that level?

 

[acsimpson]

Yes, there is no outflow into the drywell until the water level reaches the 0.5' above the bottom of pond elevation

 

[psmart]

You can model your drywell as a compound outlet device:

Device#1 = Exfiltration, Routing=Discarded
Device#2 = Horizontal Orifice, Routing=Device#1

This will require the water to flow over the rim (horizontal orifice) before it is allowed to exfiltrate.

For the exfiltration device, you will need to set a fixed flow in CFS. You can't use the velocity option in this case, because the drywell is downstream of the weir and not actaully part of the pond storage. For additional information on exfiltration options please see

http://www.hydrocad.net/exfilt.htm