[Ondřej]

Hello NicoB,
I am also using the QGIS with the RIVERGIS plugin and that problem never occured for me. In HEC RAS use RAS Mapper to draw new XS with use of the DTM. First you need to import the DTM in TIF format to RAS Mapper.

[Ondřej]

I removed all the leeves from the model and everything looks good without that error. I also removed the interpolated XS, beucause they caused even more mess. n my model now the overbank flooding occuring, which is not what I want, in some cases it is ok. But I still wondering if is there a way to make the leeves work without described problem above.

[Ondřej]

If I insert interpolated XS between the measured cross sections the flooded area remains same, in some cases the problem is worse.

EDIT: The cross sections are interpolated by 5 meters.
Q-5

Q-20

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