HEC-RAS Encroachment Problems
HEC-RAS Encroachment Problems
(OP)
I gave up trying to get method 4 to work properly. I was trying to set a 1' rise and only the furthest downstream section would show a foot rise and by the time I got 150' upstream no rise at all. Now I'm tediously using method 1 but having another issue. In the cross section viewer the encroachments are showing up in the correct place but the water surface/filled in water surface is inside the encroachment. (Please see attached screenshot) Also the left and right bank offsets don't appear to be doing anything. I think I can work around having to use method 1 from scratch and the bank offsets not working but the water filling in the left encroachment is an issue. Has anyone else had this problem?
RE: HEC-RAS Encroachment Problems
Note that you need to define encroachments at every cross sections, not just the downstream most cross section. You can watch this YouTube video and it describes modeling of HEC-RAS encroachments using GeoHECRAS, plus a lot of modeling tips when dealing with encroachment studies.
RE: HEC-RAS Encroachment Problems
I had I started to suspect having encroachments in the channel may be the problem with the method 4 not working. The issue that's creating me so many headaches is the 100 year water surface elevation doesn't leave the channel. So the floodway and floodplain are both entirely within the channel. I've got an area that's zone A that I'm trying to do a LOMR for to get the limits of the floodplain pulled back away from a property. It's a small 100 acre drainage area. So if encroachments can't be in the channel would I just show the whole thing as floodway and not show floodplain at all?