different flow (Q) for different section

[jzhang]

I have a project, which has over 200 ac drainage area, the channel running across our site till it hits an highway with a 36" RCP pipe.

I figured I shall route the inflow first, so that the flow will be reduced at other side of the culvert, and use the water elevation as my starting elevation for hec-ras study.

Couple questions:

1. When I route the basin, the outflow changes with the tailwater elevation, looks like it is a trial and error process. I need to assume a tailwater elevation, route the basin, ajust the outflow, run the hec-ras model again, adjust tailwater for the routing, and back and forth several time, is this procedure the right way to do? and is there any better way to do it?

2. In the river CAD model I will build all the sections under the same project, and how can I specify different flow for different river sections?

Please help me!

Thank you!


John

[Chris Maeder]

Note that you need to define the discharge at cross sections where there is additional flow added from tributary flow and additional runoff. Therefore, generally you reduce the flow as you travel upstream, since the flow is accumulated as you travel downstream.

To adjust the flow to account for these effects, select the cross section where you want to make the flow change. Then, select Input | Profile Adjustment. RiverCAD will then present a Profile Adjustment dialog. You can then define the new discharge. You can also navigate from cross section to cross section from within this dialog, as well as can "jump" to the next cross section (both upstream and downstream) where the next defined flow change is defined.

Remember, the key thing item is that the discharge that you define at that cross section is then propagated upstream until it reaches another profile adjustment.

If you have additional questions, please let me know.

Sincerely,

Chris Maeder, M.S., P.E.
Senior Technical Engineer