[cameron]

It can be done in either xpswmm or HEC-RAS or many other models. HEC-RAS is free where other software has costs associated with it. It sounds like your problem may have to do with initial conditions or not having enough flow going through the system. You could try adding a minimum flow for reaches, but be careful not to go to large as it will add up at the downstream end.

[cameron]

Is the wse touching the bridge at all? Bridges/culverts tend to add losses/changes to wse if they impact the flow at all.

[cameron]

Have you tried using flow roughness adjustments, depth variable roughness, or horizontal roughness to help with calibration? Not sure what the cross-sections look like, is the flow contained in the channel for high and low flows? If not, maybe some adjustments to the ineffectiveness. There is an automated calibration option in HEC-RAS that is new that you could try.

[cameron]

QGIS has a free add on to help generate HEC-RAS models. In HEC-RAS, you would have to manually add the cross-sections you like and then adjust the coordinates manually as well which is a pain for many cross-sections.

[cameron]

Not currently that I am aware of. Since the cutline lengths are not going to change, you could just import in the data from GeoRAS to the geometry and only select the n values to import (not the terrain).

[cameron]

HEC-RAS generates a interpolation surface from the cross-sections (can see it in Mapper), this is what it uses for the mapping. This is no different that how GeoRAS worked and you have to modify it manually in another software or modify your cross-sections to be longer. .

[cameron]

have you tried it with having a small slope at the beginning of the curve? Have you tried to change the time step?

[cameron]

In General, if the value is marked as None then it was not used in the simulation and the default roughness value was used. For the results rows, I don’t think the roughness has any impact on what is displayed. You can change the terrain in the results layer and this will update the floodplain based on the different terrain, but not change what was calculated (use same wse).

You can check the cell face roughness values to verify the correct values were used.

[cameron]

If you right click on the Results layer and select the Render Options, you can specify what depths are shown. I believe the default is 0.001 meters.

[cameron]

Have you tried it on a different machine?

[cameron]

The diffusion wave solver does not give many warnings when running and almost never crashes even if the results are terrible. I prefer to use the full momentum which does crash if the time step is to large. I would switch to the full momentum to see what happens. I would also look at the velocities generated from the diffusion wave run to see if there are any that are unrealistic.

[cameron]

I would try opening the raster in either QGIS or ArcGIS and export it out to a raster, which will hopefully add the no data tag.

[cameron]

I would start doing tests by removing items until I found the issue. In your case, I would start with the levees by removing them all and adding them back in 1 at a time until the problem occurs.

[cameron]

To find a face, right click on the mesh in Mapper and use the “find” option. How was the terrain created, did you combine data that might have left a gap in it?

[cameron]

have you tried deleting all of the *.hdf files and recomputing the 2D tables?

[Author]

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