Encroachments in Hec-Ras
Encroachments in Hec-Ras
(OP)
Hello All,
I seem to be having trouble performing the encroachment calculation for my model.
I created a second profile (PF2) with the same flows and cross sections as the original (PF1) and ran the encroachment option using method 4 (with all cross-sections designed to have a 0.2' rise), which is as per my state's DEP requirements. The results are bizarre!
Instead of showing a 0.2' rise, many of the water depths for PF2 remain unchanged, and some when compared to PF1 show a rise in water depth up to 2 feet! Does this sound like something anyone has encountered? I could provide any information that you think would be helpful to diagnose the problem.
FYI, I have used this process successfully, years ago - probably an earlier version of hec-ras. So i feel that the error may have to do with this particular model.
Andy
I seem to be having trouble performing the encroachment calculation for my model.
I created a second profile (PF2) with the same flows and cross sections as the original (PF1) and ran the encroachment option using method 4 (with all cross-sections designed to have a 0.2' rise), which is as per my state's DEP requirements. The results are bizarre!
Instead of showing a 0.2' rise, many of the water depths for PF2 remain unchanged, and some when compared to PF1 show a rise in water depth up to 2 feet! Does this sound like something anyone has encountered? I could provide any information that you think would be helpful to diagnose the problem.
FYI, I have used this process successfully, years ago - probably an earlier version of hec-ras. So i feel that the error may have to do with this particular model.
Andy





RE: Encroachments in Hec-Ras
I've noticed that I get very high delta WSELs in areas near bridges, culverts, and reaches with many sections in close proximity. You may try to import all values to Method 1, and then manually alter your encroachments until you get a working analysis. This will give you an idea of where you can encroach more and where you have encroached too much. It's tedious, but, to me, the only way to be sure you don't have any crazy encroachment patterns. Also be sure to take into account any existing regulatory floodway encroachments, if they exist.
Good luck!
RE: Encroachments in Hec-Ras
Glad to know that i'm not alone, if nothing else.... but no matter what i try, i cannot seem to "encroach" portions of my model. i tried the encroachment procedure on a file that i had from a little while back and it works fine, it's just this file. I'm out of options, except adding cross-sections to make eliminate all of the warning messages, etc.
andy
RE: Encroachments in Hec-Ras
i painstakingly am doing the encroachments using method 1, one by one, moving from upstream to downstream, careful so that i do not upset the water surface for the upstream cross-sections. Thanks, this seems like the only way. what a pain!
andy
RE: Encroachments in Hec-Ras
RE: Encroachments in Hec-Ras
RE: Encroachments in Hec-Ras