Modeling a channel

[Gunns]

I am modeling a channel has a pond to account for storage in the channel. I have split the channel into 6 sections because there are crossings that connect the channel by culverts between 3 of the section. At the outfall I used a pond to account for storage there. I want to account for tailwater effects and reverse flows since I have heads suggesting reverse flow. Can I reverse flow from the outfall pond to two sections that flow into the outfall?

Also is there away to have flow from a link in two directions?

 

[psmart]

If there are tailwater warnings, first set the routing method to Dynamic Storage-Indication (DSI), and re-check the results. You probably have tailwater, but not actually a reversing flow, which is somewhat harder to model. For details please see

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

 

[Gunns]

OK, I switched the routing method and I got 15 warnings (3-87, 4-93, 2-95, 2-90, 4-80) so my understanding from these warnings is that my system is so much tail water that the system is backing all the way up my channels.

 

[psmart]

The warning messages are telling you that there are problems in the model, so you really can't draw any conclusions at present.

Changing the routing procedure after you have already set up a compelex model can often lead to multiple warning messages. Its much easier to build the model gradually and check the results as you go.

That said, the warning messages will provide guidance about how to fine-tune the model. But what stands out is message 87 (oscillations) and 93 (overfilled storage). You must resolve these conditions before you can draw any conclusions about the behavior of your system. I assume you've clicked each message for details. I suspect the overfilled storage is the primary problem. For details please see

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

I also suggest you break the model apart and look at just a couple of nodes. After these are working properly you can gradually reconnect the rest of the systemm, as if you were building from scratch. Please see

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

If you have further questions you may want to email your file to HydroCAD support for individual assistance. However, the process will be the same: Understand and resolve all warning messages!