how to merge rivers?

[Arnaud]

Hello

I have got problems simplifying an existing Hec-Ras geometry.
For the sake of the example, say I have a geometry with two rivers: the river "main", which has two reaches called "upstream" and "downstream", and the river "tributary" which has a unique reach flowing into the river "main".

I want to simplify this geometry by removing one reach and the junction. Unfortunately the reach I want to remove is the reach "upstream" of the river "main". Therefore, if I want to remove the junction I have to merge two reaches belonging to two different rivers ("main - downstream" and "tributary").

I tried to do this by, first, deleting the "upstream" reach of the "main" river, and then deleting the junction. When I try to delete the junction (and therefore to merge the rivers), I get a message saying that stations downstream of the junction must be lower than stations upstream of the junction.

I thought that Hec-Ras would automatically accomodate for this and re-calculate the stations along the merged tributary, but this is not the case.

Could anybody help me?

Thanks a lot.

Arnaud

[jarvus lunt]

From the geometry editor, select the Tables menu, select Names>River Stations. Select the reach in question and then highlight the entire column (click at the top, use cntrl + a, etc). Then add a constant so that the river stations downstream of the junction have a smaller river station than the ones upstream.