1D No-Rise analysis problems

[RAS_]

Hello,

I'm working on a 1D HEC-RAS no rise analysis for a site, after construction (long story). Development included changes in the overbank at one XS, mostly cut. Pink is post-project on the graphic below.

The floodway run doesn't have a rise, as one would expect here. The 100-year run has a significantly decreased WSE for two XS upstream (0.1', 0.2') but slight increased WSE (0.04') at the third upstream XS.

In my mind, this is a "no rise" but the model needs a few changes to prove this.

Adding (interpolating) XS upstream seems to help but not sure how this is received on the FEMA end.

Thoughts?


w

 

[Ekenny_G]

No interpolated XS allowed in FEMA model. However, the No-Rise you mentioned is very close. You can play around with adjusting bank stations either up or down to eliminate the small increase.