Default to critical depth in one model but not in another

[Yuna C]

Hi There,
I have model with existing condition and proposed condition.
in the proposed geometry data,cross section details from stn1052 were modified. My task is to contain the 100 year water level within the proposed cross section. This was pretty much achieved however I have some problem at the transition area (eg, the cross section right upstream of the modified cross sections) which is stn1071-1052.
In the existing case, the model seems able to calculate the actual depth in the channel for stn 1071-1052, however, in the proposed case, the model seems not able to solve the energy equation, such that it adopts the critical depth.

I have the exact same steady flow in both cases.

Is there any way I can improve the model for the proposed case to calculate the actual depth? I can’t modify the cross section at stn1071-1052 as it is outside the project boundary.

here is the water level profile for the existing and proposed cases:(pink lines are proposed water level and critical depth, blue lines are existing water level and critical depth)

[Anonymous]

I assume you are modeling in the unsteady state?

I always try using a pilot channel and increasing Htab parameters. Youre model may be drying out causing instability.

[Author]

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