HEC-RAS Merging reaches

[rinkrat]

I have two different reaches for the same river system. They were developed separately and one flows right into the next. This is not a junction problem. Is there a way to merge them into a single reach. I know how to re-station. I just need to turn RIVER REACH 1 & RIVER REACH 2 into a single system with just RIVER and REACH. I have geoRAS and could use that. I think I have a brute force method to do this, but I am looking for a more elegent / simple solution.

Thanks

[jarvus lunt]

There are some various ways to handle this inside of RAS. What you need to do is not very obvious and it depends on how things are set up.

When you say two different reaches, do you mean two different reaches in the same geometry file, or in different geometry files, or in different projects?

Is the river stationing of the two different reaches consistent (and do they have the same reach name and river name)?

One approach you might look into, on the geometry editor under file there is an option to Import Geometry Data... You can use this to bring in geometry data from a different geometry file (the geometry file can be from the same project or from a different project). If you you import cross sections with the same reach and river name, RAS will assume that they are part of a single, continuous river.

[rinkrat]

The reaches are in different geometry files and different projects. I have no problem importing one into the other. They are geo-referenced and line up fine.

The stationing is different in that both start a 0 and go up. That will have to be adjusted, and I know how to do that.

The reach and river names are different, but can be made the same.

I figure that if I can get RAS to see the two as a single river / reach system then I can restation and go from there.

[mcmillen]

Rinkrat-

I am having the same problem that you described. I have tried to import my separate geometry files and rename the river and reach identifiers so that they are the same. This doesn't seem to solve the problem, as HEC-RAS doesn't route the flow from the upstream portion to the downstream portion.

Were you able to find a solution to your problem, and if so would you mind offering some guidance?

Any suggestions would be appreciated.

Regards.

[jlewis]

Here is a trick to combine two reaches.

In the geometry window go to Edit->move object, this will show the vertices in the stream centerline. Move the vertices by clicking and dragging one end of a reach on top of the end of the other reach. This will prompt a "create junction" node. It may take few times to move the vertices around to get this window, there is some kind of snapping tolerance. Name the junction and then delete the junction. It will ask you if you would like to combine reaches, click yes and it will combine reaches.