Problem with dam simulation

[nicocajs]

Hello,

I am new in HEC 2d simulations and I am training to simulate a dambreak phenomenon. When I execute the unsteady flow I have the next problem:

has a weir elevation lower than the cells they are connected to for 2D Area 2d
This is not allowed in HEC-RAS

How can I solve it? I read similar topic but I can not found the solution.

Regards

[Scott Miller]

From about station 0 to 300 and then 1800 to the end, the weir is below the terrain. That is what the error is about. Either shorten the weir, or raise the ends of the weir above the terrain. To raise the ends of the weir above the terrain, click on the terrain profile button and copy the profile table. Paste it to a spreadsheet and add a few millimeters to the elevation. This helps stay above the headwater and tailwater elevations for each cell, which look like steps in the graphic.

Remove any rows where profile elevations are lower than the weir elevation, and set stations at the ends of the weir to the weir elevation (at about 300 and 1800). Open the weir/embankment data and paste the station-elevation numbers there. Double check to make sure the new elevations do not cut the corners of any of those steps. That should take care of the error.

The breach should not go lower than the headwater terrain elevation, or there will be a similar error.

[nicocajs]

Scott,

Many thaks!!! Regards

[benp]

Hello,
I have the same problem with HEC-RAS 6.0.0 Beta update 1+unit SI
“has a weir elevation lower than the cells they are connected to”
But my weir is higher than cell (see image below)

I tried different approoach with no success:
– Using exactly this procedure (import shape file in geometric data editor+edit weir): https://www.youtube.com/watch?v=au1Hyqt7drA
– Draw SA/2D connection in RAS Mapper and edit in geometric data editor
– Clip Weir Profile to 2D cells

[benp]

Reply to myself…

It is possible but difficult to use the weir:
– The weir must be created in the geometry editor and not in ras mapper
– You must not modify or erase the weir or culvert either in ras mapper and in geometry editor
– Once the message “has a weir elevation lower than the cells they are connected to” appear, it is impossible to remove it even if you delete and rebuild the weir.

Other tests:
The computer date (before 12/2020) don’t change anything.
The imperial units are maybe less buggy (I am not sure).
The bug is the same in 5.07

So keep a clean copy of your folder project and use it if the bug appear…
If somebody find a better workaround to clean the bug, write it here!

[Author]

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