I’m trying to get a LOMR approved through FEMA using the model provided by the FEMA library. My project is located at the very upstream end of the reach, downstream from a junction with two other reaches. My issue is that I need to restrict any changes to the WSEL to my project area but even when I’ve matched the WSEL on the upstream cross-section in the project area, there is a ripple of differences in WSEL, EG elevation, EG slope etc. far up through the other two reaches- up to 7 cross-sections and 1200′ in one reach and 7 cross-sections and 600′ in the other. The WSEL differences are small, mostly in the range of .01 but I need them to be 0. In my experience this seems excessively sensitive. I don’t work with junctions often. Can anyone tell me why this is happening? Does it seem normal? Any tricks for reducing the impacts across the junction?
I’m running steady state with the energy computation method.