Less fill- higher water level with one discharge, not with other discharges

Hi!

Less fill- higher water level with one discharge, not with other discharges

water level upstream with different discharges:

discharge less fill more fill
20 81.13 81.13=09
28 81.38 81.37=09
30 81.41 81.42=09
40 81.56 81.58=09
100 82.16 82.2=09

What do you think this could be caused by? The Froude number is below limits. Could adding the number of cross sections help?

Yours,
Markku Lahti
markku.lahti@fortum.com

[Chris Maeder]

Dear Markku Lahti :

Note that I looked at your HEC-RAS model with HEC-RAS 2.2, 3.0, and 3.1. Seems that the problem must be with how you have defined your cross-sections. They do not show any overbank areas--simply the bottom of the river. Can you define the entire cross-section geometry?

See the problem in the attached screen capture.

Sincerely,

Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com

Thanks!

So, it is so, that the calculation model needs that there exist some
overbank areas?

Yours, Markku

Dear Markku :

It could be a possible explanation for your model. It seems that HEC-RAS
is having trouble even displaying the river centerline.

Sincerely,

Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com

Oh, yes, it may also be caused by the fact, that I have programmed a
data handling program, that writes this kind of input file, which can be
read directly in GIS-format to HEC-RAS. It didn't show the centerline
correctly, and I think have not programmed the overbank areas to be put
into the file. If I put those also there to the already read profiles,
that could be checked.

Thanks,
Yours, Markku