r/HECRAS

Hi everybody,

in my company Hec-Ras 6.x is currently the standard for 2D unsteady flow computations. I personally am looking forward to switching to HR 2025 as soon as possible, but we're not yet sure weather it is already practical.

What are some of your first impressions with the program? Is it better than HR 6.x? Is it already usable für 2D computations or are there still to many bugs and issues?

Hey everybody.

I am modeling a Dam Break cascade model in HEC RAS. Is it better to model the reservoir as a storage area, or if I can keep as a 2D flow area?

For both dams, I have a DEM with great resolution (0.5m), so I thought that it wouldn't be a problem to let as 2D flow area. Also, I am not sure which one is better regarding model stability.

Both dams are flood control dams.

Hello everybody.

After running a model for the first time I got some results. Now changed my mesh with more breaklines and refinement regions, and also the cell size. The simulation is still running as I am writing this, but I am already asking myself:

• How can I validate the mesh that I created?
• What can I do to compare different meshes? What result should I look to?
• Does HEC RAS have some results for 2D flow simulations that can help us to see if its making sense?

I'm having an issue where my calculations get corrupted because Windows keeps switching the decimal separator from a period to a comma due to IT settings; is there a way to change HEC-RAS to a "European" format?

https://preview.redd.it/whgcum3ul30h1.png?width=1071&format=png&auto=webp&s=0e17025e2acbaa00e45ae3a29fa79352048076ee

I used to get this error sometimes when editing geometry and trying to save. But it would always go away after reopening the RAS Mapper. So, I had not given it much concern. But this time, I keep getting this error whenever I wanna draw a profile line to look at the different profiles available. The reopening thing is not working. And the issue exists in only this model and drawing the profile line is really important for me to analyze my model. Can someone please explain the reason behind this issue and tell me how can I solve it? I really dont wanna redo this model because it took so much of time for me to prepare this model.

Hi,

I’m currently learning HEC-RAS and trying to improve my practical understanding of hydraulic modelling and flood simulations. If anyone is comfortable sharing some of your old HEC-RAS projects/models (academic, practice, or any professional examples with non-sensitive data), it would really help me assess and improve my workflow and understanding.

I’m especially interested in:

- River/flood modelling projects

- 1D or 2D simulations

- Bridge/culvert modelling

- Terrain preprocessing workflows

- Manning’s n calibration examples

- Real-world project structures and organization

Hi, I'm working on a dam break model, I have an unsteady flow slowly filling my reservoir and a breach that requires 0.1s computation time. I used the advanced time step control to improve overall speed.

worked very well until yesterday where it was acting the exact opposite as it should (low time step on slow filling and larger time step as soon as the breach happens), with the exact same files (geometry, input, parameters...).

I've compared every parameter with my backup files but I can't find any difference.

What can be the problem ?

I am working on a large floodplain model and doing most of the build in Geo HEC-RAS. The geometry file has stopped displaying/rendering. It’s still there, the model runs, and if I drag/click to select in the right spot, pieces of the model (XS and reaches) will highlight like normal. The geometry displays normally in HEC-RAS, and old/other geometry files in the same model display fine in Geo. Which makes me think something I put in the geometry made it disappear.

Has anyone encountered this?

I have rebooted. Resaved the model in RAS, resaved the geometry. Going to start deleting my recent edits (many road crossings) to see if one move brings it back.

I know I could switch back to RAS mapper, but at this late stage I’d like to keep building with the setup I have now

Hello!

I’m working on a river modeling project in HEC-RAS and I'm still a beginner and had a couple of practical workflow questions:

1. What’s the most efficient and accurate way to draw cross-sections perpendicular to the river channel?

   - I’m currently using GIS (QGIS) to digitize them, but ensuring true perpendicular alignment along a meandering channel is tricky.

   - Are there recommended tools, plugins, or workflows (centerline-based, stationing methods, or automated XS generation) that work reliably?

2. How do you accurately determine bank stations in a cross-section profile?

   - Do you rely purely on DEM breaks in slope, field survey data, or visual judgment?

   - Any best practices to distinguish main channel vs overbank areas, especially in flat or subtle terrain?

Would appreciate any tips, workflows, or common mistakes to avoid—especially from people working with GIS + HEC-RAS integration.

Thanks!

Hello everyone. I’m trying to display results from an alternative 1D simulation run, but the mapper is only showing the current results (depth and velocity). On the other hand, for the alternative run I can’t see any results in the mapper, although they are visible in cross sections and profiles. I work in v 7.0 .Thanks!