Reliability of supercritical flow computations in unsteady models

[Lih]

Hi, still working on the model I posted about earlier.

I'm trying to figure out the limitations of HEC-RAS 3.1.3 at computing supercritical flow water levels. In one section of my model there is a concrete channel. When viewing the Max WS profile the water surface always reverts to critical depth along the entire length of the concrete channel. There is a weir at the upstream end and I know there should be a hydraulic jump downstream of the weir (profile doesnt show this).

I have high water marks along this reach and currently the water levels are too high and I think it's due to the falsely elevated water levels. Is this simply a limitation of the model that I need to be aware of, or is there a way of inducing supercritical flow (without making the model unstable)?