Isolated Inundation

[susanta]

Hello everyone, I am running steady analysis. The resulted model is showing isolated inundation. Some regions with elevation more or less equal to the channel area, but separated from the channel by higher elevations are also getting inundated. I can’t exclude those regions from the cross sections also. Those are within the flood plain. Obstruction/levees are not helping. Which type of analysis will be suitable for such regions? Can anyone help me in this?
Thanks.

[Anonymous]

Susanta,

It may not be the easiest solution, though it may be, but I would suggest trying to model the overbanks/floodplain with a 2D Flow Area (available in RAS 5.0 Beta). If you’d like to maintain the XS data, as is, in the model (with wetted low spots, as mapped), then you might consider a simple post-process to clip the disconnected mapping. Though, if the mapping that appears disconnected is in fact active during large events, another look at the modeling approach may be warranted.
Let me know if this isn’t helpful,

David

[susanta]

Thanks David! I will try and let you know.

Susanta

[Anonymous]

Susanta,

I should have noted Chris has a good explanation, within the blogs, of fragmented mapping using a 2D approach (or 1D/2D), why it happens, what it means, and things to consider in handling.

http://hecrasmodel.blogspot.com/2015/02/2d-troubleshooting-fragmented-inundation.html

David

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