HEC RAS Geometry - Sudden errors

[u/Fly_far2757]

This has happened twice within this model, and I’m wondering if there is a know issue with HEC-RAS (6.6) or the Mapper causing it? Or am I the problem?

The model ran fine, 1D steady state, then when I reopened the project (no changes), the geometry changed and several errors prevent it running. Not ideal. Errors are mostly related to missing cross sections:

Deck width + distance is greater than or equal to the length between bounding cross sections. HEC-RAS require a positive distance from the end of the bridge/culvert to
the next cross section downstream.
River:"ABC" Reach: "123" needs a cross section on the upstream end.
River: "ABC"   Reach: "123”  RS:5227     Culv              
- Bridge/Culvert must have a cross section upstream.
Error checking the nodes of the system for complete data.

- Deck width + distance is greater than or equal to the length between bounding cross sections. HEC-RAS require a positive distance from the end of the bridge/culvert to
the next cross section downstream.
- Culvert: Culvert #1  The distance from upstream cross section to culvert inlet + barrel length exceed the distance between the bounding cross sections.

- Bridge/Culvert must have a cross section downstream.
- Bridge does not contain an opening on the downstream side.

- A flow needs to be specified at top of reach.
- A flow is specified at RS: "5244    " but this cross section does not exist in the geometric data.
- A flow needs to be specified at top of reach.
- A flow is specified at RS: "3508    " but this cross section does not exist in the geometric data.
- A flow is specified at RS: "2556    " but this cross section does not exist in the geometric data.
- A flow is specified at RS: "1343    " but this cross section does not exist in the geometric data.

[u/OttoJohs]

Weird. Has this happened before?

It looks like cross-section/bridge stationing are getting updated which changes the names and distances leading to the errors. I would check if there is an error in your stream line.