2D Area Connection

[AJ]

I have two 2D areas connected with a SA/2D Area Conn. When I try to run the model I get an error saying the weir elevation is lower than the cells they are connected to. However, when I check the cell elevations on the HW side listed in the error message, the cells are not connected to the SA/2D Area Connection (i.e., the cells are in the middle of the mesh no where near the connection). It appears that HEC RAS is comparing the weir elevation to the elevation of all cells in the 2D mesh on the HW side of the connection.

Can anyone provide any help on how to fix this or a workaround?

[Anonymous]

It sounds like the geometry is out of date and RAS isn’t re-computing things like it should. Go to RAS Mapper. Right click on the Geometries layer and make sure the terrain data is associated.

If that doesn’t fix it, open up the geometry name (that is under Geometries) and right click on 2D Flow Areas and select Compute 2D Flow Area Hydraulic Tables.

If that doesn’t fix it, I’m not sure. You might try deleting and then adding back the connection.

[AJ]

Thank you for the suggestions. I tried all of them but it still shows the same result. I had read somewhere (possibly this forum) that it was a bug in the beta version but I would have thought it would be fixed by now.

[Lonnie A]

It sounds like a issue with the model and not the software. Are you sure you are referencing the 2D areas correctly as HW and TW? Are the cells it is noting perhaps in the area you consider to be TW and not the HW? Regardless the weir elevations has to be higher than the connecting cells of both 2D areas.

[Paige]

Did you ever figure out a workaround for this issue? I am having the same problem with my model.

[Anonymous]

Hi guyz, last week I was doing a fun simulation scheme, and suddenly get caught by what this forum topic is all about: an error in 2D AREA Connection.

How did I get rid of it, well, maybe its a combination of thing, let me explain myself…

First, check in ArcGIS if your roadway alignment shape or your culvert shape is a single polyline… very easy to make a mistake in generating a profile line in two shapes all at once!

Secondly and well hidden: in the check boundary conditions. If you put an hydrograph in US Boundary Condition, then don´t forget to provide an initial EG slope for distributing flow along BC line…

With, hope you could solve that issue!!!

Cheers!

[Author]

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