HECRAS Error Message re: Cross Section Height

[dneal]

We are modeling a creek that has a profile of 0.35% and a 100 year flow of 1660 cfs. When running the analysis, the computation routine runs to completion but the following error message is generated:

"The elevation of the cross section needed to be extended. Doubling the height of the cross section four times was not sufficient. The cross section should be examined and coded to a new height."

The cross section in question is deep enough to contain the 500 year flow, although at this section for some reason the 25 year flow is well above the 500 and 100 year flow.

Have any of you encountered anything similar?

Thanks in advance.

David Neal
dneal@volkert.com

http://www.volkert.com

 

[gbam]

Have you examined your cross section data for that specific xsec and those bounding it? Plot a profile and xsections to see if there is bust in geometry. Could be a transposed number if data was keyed in. I have found some "key-in" busts from these plots. Good Luck

 

[francesca]

I have found it most useful to check the velocity reported for each cross-section. Most depth busts correspond with near-zero velocities, which correspond with geometry busts (failure to account for ineffective flow areas, typo, etc.).