Reverse Flow

[Findlen]

Peter, just to verify: If I have several culverts, modeled as Ponds, all feeding an actual pond, it is not possible to model reverse flow from the actual pond to all of the culverts feeding the pond (rather, it is only possible to model reverse flow to 2 of them, 1 as secondary, and 1 as tertiary) - is that correct?

 

[psmart]

That's true. However, I would always start by assuming one-way flow, and then check the warning messages to see if you really have a reverse-head situation that actually requires the modeling of reverse flow. In most tailwater situation the flow does not actually reverse direction, so you can use DSI routing without the reverse outlets.

If there is reverse-head, you should also consider consolidating the ponds so as to avoid the need for modeling the reverse flow.

For details see

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

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[psmart]

I should also have mentioned: You can only model reversing flows between ponds with significant volume. You cannot model a reversing flow involving a zero-storage pond, because there is no storage volume to receive the water.

So it comes back to a basic issue of what you're trying to model, and where you expect the reversing flow to go. If it will reverse up the pipe, where does it end up? You need to look at the bigger picture and work out the best way to simulate the overall behavior.



Peter Smart
HydroCAD Software

http://www.hydrocad.net