Adjust geometry of each cross-section???

[Van PD Tri]

Hi there,

The questions are:
+ In the case that the geometry extracted from DEM via the HEC-GeoRAS module is not good, should we adjust each individual cross-section in HEC-RAS (based on the observed data)?
+ And if we adjust the cross-section in HEC-RAS and the calculated flooding pattern in HEC-RAS is imported (back) in ArcGIS, is the flooding pattern produced in HEC-RAS and shown in ArcGIS acceptable?

Any help is very appreciated.

Best regards,

Tri Van

[MattZ]

1) HEC-RAS models are only as good as their input, especially when geometry is concerned. So, I would say that your best option would be to use the best available data and incorporate the observed data into your TIN.

2) You should map the floodplain with the data you use in your HEC-RAS model. So you should incorporate the observed data into your DEM data and map with the combined TIN.