Sediment Transport

[Anonymous]

Hi guys. I’m trying to perform a sediment transport analysis, and I’m having a tough time of trying to figure out what RAS needs from me (The reference manual is not very descriptive).

When I go to run my model I’m getting an error that reads:

River: “TC17 Channel” Reach: “TC17 Channel” RS=6700 – has a zero flow value.

This makes zero sense to me, becasue I’ve already given my reach flow data in the Quasi Unsteady Flow Editor!

What am I missing?

[Chris G.]

Hard to say, but RAS needs flow in that cross section. Make sure you have flow inputs at all the upstream ends of your model for the full time series.

[Anonymous]

The flow series only needs to be specified at the most upsteam cross-section, right? Thats how I have it set up.

[Chris G.]

Upstream cross sections, yes. If you have a dendritic system, there will be multiple upstream cross sections (one for each branch). Make sure each one has a flow input.

[[email protected]]

When I was doing it for my thesis sometimes I also had to undergo periods of confusion and mess due to no prior experience of HEC RAS. And I also learned many things by the same way as you are doing i.e. asking for help :).
If you are still unsolved, you can send me your files with a description of problem and your reach. I do not promise but hopefulyI can guide you a bit.

[Andreas]

Hi, sorry for my english, I hope it’s understandable.
I had the same problem with my simulation. To solve the problem it’s very important to set the
“Ending Date” in the “Simulation Time Windows”. Remember to fill the temperaure table in the
“Quasi Unsteady Flow Editor” and save all files (Geometry, Quasi Unsteady, Sediment) before every run.
Altough you can look datas in the dialogue boxes, HEC RAS don’t use the datas for computation before
you click on “save” button.

[Anonymous]

Check simulation time , i had the same problem and it solved !

[Author]

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