Culvert as downstream boundary condition

[albertini89]

Help please!!! I need to model a culvert as a downstream boundary condition, meaning the water exits my 2D model via a circular culvert. Is this possible? And if so, how can it be done? I tried building a weir (as SA/2D connection) to simulate a wall with a culvert going right throught it. However, when I try to run the model this error pops up: “Barrel #1 on structure X does not entirely intersect the downstream area XY-2D”.

[Luis Partida]

Put a 1D storage area at the end of your mesh. Then, connect the 2D Mesh to the 1D storage area via a SA/2D Area Conn. In the Conn you can add your culvert. The 1D SA volume can just be set as infinite. Hope this helps

[albertini89]

Thanks for your reply Luis. This sounds logical. But how to set the volume as infinite?

[Luis Partida]

Its not a direct setting it is just a way to tell the user to add volume at your discretion. You control how much volume a 1D SA has. Create your own table in the 1D SA editor

[albertini89]

So I’ve built the storage area connected to the 2D flow area via a SA/2D Connection (wall with culvert). But for some reason, now the water is ignorig the wall completely. The following error popped up during the simulation:

Overall Volume Accounting Error in 1000 m^3: 3.141
Overall Volume Accounting Error as percentage: 11.48
Please review “Computational Log File” output for volume accounting details

[Luis Partida]

Since you are modeling a wall, there is no need to extend your 2D area beyond that location. This is odd and I would look at a time by time basis to see when water gets beyond your wall. Is water even going through that culvert? It seems like its not. I believe you can also ignore the SA and just set your tailwater conditions to “out of system”

[albertini89]

OK, and where can I specify this “out of system” option?

[Luis Partida]

Sorry bad advice, that isn’t an option in the SA2D conn editor only in lateral structures

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