Missing initial condition – 3rd round

[Adolfo]

Hi, I’m running a fairly simple simulation (RAS 4.1.0), a river reach and a storage area connected with a lateral weir upstream and other downstream. I’m fairly familiar with hydrodynamic models and with RAS.
The simulation runs properly, generates reasonable results (i’ve checked the hydrographs and so on), but at the beginning of the post-process i receive an error message “Incomplete data, the following errors were found: Storage Area:”barrio Remo” – is missing some initial elevations in the steady flow data.”, and the post-process aborts.
I’ve tried several times, verified the initial condition for the storage area, run a steady simulation (it run ok!), and some other tricks, to no avail. As the code runs properly (no instabilities, not even in the storage area or the weirs), it has all the data it needs, so what’s the origin of the error message?.
I’m not surprised, i’ve already seen a lot of weird computer behavior and made a lot of silly mistakes when using them, but i do need the post-process results for the reports. Any ideas?

[Adolfo]

I created a new project, and begun switching on and off the three components (1 storage area and two lateral structures) that generated the error. It seems the problem is generated by the connection between the lateral weirs and the storage area. If the weirs discharge “out of the system”, not only does the simulation run fine, but also the post-processing is okey. When i connect one or both weirs to the storage area, the simulation runs ok, but then the “missing initial elevations” message appears. Up to now i haven’t been able to find anything related to lateral structures initial conditions in the manuals.
Any ideas?

[Chris G.]

That is very weird. I’ve never heard of that, especially after the simulation runs just fine. I suggest you package up your plan and send HEC a bug report on that one. The error suggests that you don’t have initial elevations for your storage areas input into your Initial Conditions Tab in the unsteady flow editor. However, I wouldn’t expect the model to run at all if these were missing, so I’m a bit stumpped on this one.

[Adolfo]

I’ll follow your suggestion and send HEC the problem. As for the storage area initial elevation, it is properly set, I’ve checked it a thousand times. I’ve tried all i could think, including exploratory surgery, RAS files are usually ascii and i’m very old school, ferrite core, so it was just like old times. Nothing worked. Let’s see what HEC thinks of it, and i’ll keep trying to imagine what the heck is going on.

[Adolfo]

I sent a bug report to HEC. Meanwhile, i kept messing around with the project, and it begun working! I updated my email to HEC with the new information, see it below

“Regarding my yesterday’s bug report, I have some additional information. I was using a 3 h computation interval, a bit large considering the distance between river stations, but it is a very slow river, and also a preliminary simulation. I decided to change the time interval to 1 hour, and, presto! the error message disappeared, and everything seems to be working fine.

Even if a 3 h time interval were grossly wrong, symptoms would quite different, instabilities or so, not a “missing initial condition“.

Any ideas?

[BenC]

I work with HEC-RAS 4.1 and I have a problem quite similar with the one you presented here on june :

I’m also running a simple simulation (RAS 4.1.0), a river reach and three storage areas located at the end of a reach. As it didn’t work, I kept only one storage area and still have the same problem as yours : “The simulation runs properly, generates reasonable results (i’ve checked the hydrographs and so on), but at the beginning of the post-process i receive an error message “Incomplete data, the following errors were found: Storage Area:”BR1″ – is missing some initial elevations in the steady flow data.”, and the post-process aborts.”

I read your message sent to HEC and I tried to reduce computation interval but it didn’t work.
Did you receive any answer from HEC ?

Thanks
Benoît

[Caroline]

Hi,
I think I know what is missing. I had the same problem, of some reason you need to add the data not just on the boundary condition tab.

Try to look at the steady flow data. Go to Options and then “Storage Area Elevations”. There you can add the missing elevation data (again).

Hope that helps
Caroline

[BenC]

Hi, thank you for your answer even if… it didn’t work…
I added elevation data where your said (steady flow data/options/storage area elevations). I kept values in unsteady flow data/ initial conditions.
I ran unsteady flow analysis and the same message appeared :
“HEC-RAS Error – Incomplete data, the following errors were found:
Storage Area:”BR1” – is missing some initial elevations in the steady flow data.”…

I continue to try other modifications..
Any other idea ?

[Caroline]

Sorry, I thought you were modeling steady state. I have no clue then.
I guess you did already add the elevations in the boundary tab for unsteady flow?

[BenC]

Thank you. Yes I did it
This error message “Incomplete data, the following errors were found: Storage Area:”BR1″ – is missing some initial elevations in the steady flow data.”, and the post-process aborts.” is weird beacause I run Unsteady Flow Analysis and the message ask “steady flow data”.

[Adolfo]

Hi Benoit. Sorry, but no answer from HEC. From my experience, it’s some silly bug in the interface. Why reducing the time step made it disappear, i have no clue.

[BenC]

Hi Adolfo

Thank you for your answer. I will try to modify time step again….

[Anonymous]

Apparently this error was trigged by the time window not being an integer multiple of the computational time step. When the time step was changed, the model met the condition of the time window needing to be an integer multiple of the time step, so it ran OK. Looking forward to better handling of this situation in the next RAS release.

[Author]

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