Culverts modeling in HEC-RAS 5.0.4

[Kinagoto]

Hello HEC-RAS Modelers,

I am having trouble for about a week now with a model that should be done in a day or two.

The site has two structures located downstream from a dam. The dam is set to be breached:
– Structure 1: Box Culvert 5H x 9W, Length = 966 ft, Inlet El. 19, and Outlet El. 12.7.
– Structure 2: 2 Pipe Culverts Dia. 5.5 ft, Length = 141 ft each, Inlet El. 12.6, and Outlet El. 12.

The Box Culvert discharge to a manhole which the floor is elevation 12.

I made sure all the cell elevations at the face of the inlet and outlet of all both structure are lower than the structure invert elevations.
The model runs fine with Structure 1 alone or Structure 2 alone. When I have both Structure 1 and Structure 2 together, as shown in the screen capture, I go a generic error message below.

When check Results in RAS Mapper next to the Plan I run, I stated that structure is unknown.

it is not possible to model a culvert one downstream another using the new culvert capabilities offered by HEC-RAS 5.0.4?

Any guidance will be appreciated.

Thanks,

Kinagoto

[Anonymous]

Hi Kinagoto:

I am having the same trouble to you.

Have you found any solution to this?

Greetings.

[Anonymous]

You guys gotta make sure the DS end and US end are not sharing the same cell, Make sure your GIS coordinates are different.

ALSO refine the areas much further than you have shown. If you have for an example a 5×5 culvert and your overall grid cell size is 5×5 and the culvert overlaps two cells, you may be modeling this incorrectly as the software will make its own assumptions based on the cell generated from the terrrain. Further refine this down

[Anonymous]

I agree with Luis, you need to split the cells at the junction/manhole so that each culvert has it’s own cell and preferably some cells between them.

[Anonymous]

So i had this error for the first time yesterday and this is the solution:

That error is the cause of one of your lateral structures (culverts). Through editing and constant regeneration the weir has lost its ability to be read correctly. One by one delete your culverts until your model runs without it. Stop the model once you have resolved the weir location that is the issue, re-build and then run it again.

I had to re-build about 6 cfulverts yesterday due to this error. it is what it is.

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