Rain on Grid visualization

[Stefan]

Hi all,

i am trying to get into flash flood simulations.
For this reason i have set up a simple rain on grid model on a 50cm DEM in an urban area with steep slopes.

The Elevation model is pre processed and optimized for hydro simulations (no sinks etc.).

The Problem i have is that there are many small ponds at lowest point of each cell face
Aditionaly there are very high Depth values near steep slopes.
See below:

Is this just a visualization issue or are there some greater Problems with the simulation setup?

=> Im Runing my model with 10m mesh size (just for Tests) with 1sec computation Intervalls. I tried different roughness values from 0.15 to 0.02 with similar results.

Thanks in Advance!

[cameron]

This is normal for how HEC-RAS maps flooding.

You would need to go finer on your grid cell size. I would also switch to the full momentum solver as you have steep slopes with high velocities.

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