Extrapolated above Cross Section Table

[miss_rinda]

Hai. I got this problem when running my 2D HEC RAS 5.0.7
I’m really stuck to solve this problem. Can anyone who read this help me in solving this error?

**** ERROR: Solution Solver Failed ****

Minimum error exceeds allowable tolerance at 02DEC2014 03:00:00

ABCD Reach 1 57
02DEC2014 03:00:00 1D/2D Flow error 0.0429 ABCD Reach 1 49776

***** Warning! Extrapolated above Cross Section Table at: *****
(The extrapolation may have been caused by model instability)

ABCD Reach 1 from R.S. 61007 to 59657
ABCD Reach 1 from R.S. 57750 to 57305
ABCD Reach 1 from R.S. 56545 to 55723
ABCD Reach 1 from R.S. 55234 to 54279
ABCD Reach 1 from R.S. 53923 to 53382
ABCD Reach 1 R.S. 52680
ABCD Reach 1 R.S. 52196
ABCD Reach 1 R.S. 51263
ABCD Reach 1 from R.S. 50478 to 50087
ABCD Reach 1 from R.S. 49132 to 48860
ABCD Reach 1 from R.S. 48501 to 48007
ABCD Reach 1 R.S. 46507
ABCD Reach 1 R.S. 44977
ABCD Reach 1 from R.S. 35819 to 35568
ABCD Reach 1 from R.S. 34542 to 33758
ABCD Reach 1 from R.S. 32633 to 31395
ABCD Reach 1 from R.S. 30281 to 26827
ABCD Reach 1 R.S. 25553
ABCD Reach 1 R.S. 23262
ABCD Reach 1 R.S. 21465
ABCD Reach 1 R.S. 21038
ABCD Reach 1 R.S. 19036
ABCD Reach 1 from R.S. 17829 to 16953
ABCD Reach 1 from R.S. 13315 to 11266
ABCD Reach 1 from R.S. 9996 to 8154
ABCD Reach 1 from R.S. 7341 to 57

Writing Results to DSS

**** The Model Has One Or More Error(s) ****

Unsteady Flow Simulation Terminated
Reading Data for Post Process
Simulation went unstable at: 02Dec2014 04:00:00

Running Post Processor HEC-RAS 5.0.7 March 2019

Finished Post Processing

Stored maps were not written because the simulation did not complete.

Computations Summary

Computation Task Time(hh:mm:ss)
Completing Geometry(64) 2
Preprocessing Geometry(64) <1
Unsteady Flow Computations(64) 39
Post-Processing(64) <1
Complete Process 44

[cameron]

The simple answer is that the wse is getting higher than the HTAB value and needs to be increased.

The real question would seem to be why is your model going unstable at those particular cross-sections to cause bad results?

There could a lot of different reasons and varies for each model so we would need more information.

[gaagai aissam]

hello mr cameron;
i find the same error for simulation the Dam-breach with the hec ras 5.0.7, please have you find any solution for this error???
bellow the messag:

[cameron]

Your model is going unstable. This could be due to your time step, ineffective flow areas, cross-section spacing, roughness, bridges, dam breach parameters, or HTAB inputs.

Dam breach models in 1D can be unstable and it is hard to give any advice without having more information about the model.

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