Pond Modeling - Outlet Through Vertical Pipe

[Joe_]

I have a wet pond with a permanent pool whose flow will pass through a riser structure and exit via an outlet pipe. The outlet pipe will be connected to a level spreader (see image).
For the purposes of a supplemental calculation, I was assuming that the flow from the pond outlet pipe could only pass through the standpipe/riser portion of the level spreader - not through the perforated pipe. The standpipe/riser (of the level spreader) was assumed to be about 2' high.

A reviewing agency commented and we were asked to "..please prove no backwater at wet pond riser in case of bigger storms.."

Looking at my attached routing diagram, do I have this scenario modeled correctly?

 

[psmart]

Can you explain the placement and function of the perforated pipe, and how/if it appears in the HydroCAD model.

And what are you modeling with device #1 (which appears to be a horizontal orifice)? Is this the level spreader? How is it constructed?



Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[Joe_]

The discharge from the pond outlet pipe will flow into the perforated pipe (and possibly through the level spreader standpipe for larger events). The perforated pipe is buried within the gravel bed and extends from the standpipe in two directions. The perforated pipe is intended to disperse the flow across the entirety of the level spreader.
The perforated pipe portion of the level spreader was not modeled within HydroCAD. For this calculation I was assuming that the perforated pipes were clogged and that water could only flow through the standpipe.

Device #1 was intended to be the top of the standpipe portion of the level spreader. The pond outlet pipe will connect to the standpipe of the level spreader.
I guess I'm asking how to model flow that is going upwards through the standpipe...should I be using a different outlet device?

 

[psmart]

OK, now I understand your setup. Thanks. Your outlet configuration looks OK. However, you might want to set the primary tailwater to the top of the level spreader outlet, just to verify that the 12" pipe flow is not adversely limited by tailwater.

Peter Smart
HydroCAD Software

http://www.hydrocad.net