Tide Gate Vs Reverse Flow

I am trying to model a stormsewer system that discharges to a tidal water body. The stomwater pipe systems has sever catchbasins which drain a roadway. I want to model a scenario in which a storm event runoff, say 25 year, coindes with high tide tailwater which closes a tideflex at the downstream end of the stormwater pipe. With the tide gate close under high tide, one will expect the roadway runoff water that has been building in the pipe (because it can discharged from the closed tide gate) to backup from downstream to upstream of the pipe system. Can I model this scenarios as reverse flow in HydroCAD? Also, will HydroCAD reverse flow fill up all the pipe network (pressure flow) before catchbasin reverse flow could occur? Thank you very much for your support.

 

[psmart]

All outlet devices in HydroCAD behave as if they included a one-way valve. Water will flow only in the direction of the outflow arrow. If a reverse-head occurs a warning message is generated, and no further water is discharged through that device in either direction until the tailwater falls below the headwater.

BTW, what you are describing may not actually be a revering flow - you just have water accumulating in the system due to the tidal tailwater and the closed gate valve. Although this is often referred to as "backing up", in most cases the water is just accumulating in the system rather than actually changing the direction of flow.

In a real reversing flow, the water initially flows from point A to B, and then changes direction and flows from B to A. A warning message will alert you to any such reverse-head scenario.




Peter Smart
HydroCAD Software

http://www.hydrocad.net