Dear Mohammad,

HEC-RAS model (Version 4.0) can perform three functions: (1) steady flow, (2) unsteady flow, and (3) movable boundary flow. The steady flow component uses the standard step method for the solution of steady gradually varied flow. Under steady flow, the user inputs as boundary conditions a discharge upstream and a stage downstream. The model calculates stages throughout the interior points, keeping the discharge constant. Under steady flow the discharge-stage ratings are unique, i.e., kinematic.

With my best regards

Prof. Bachir ACHOUR

You can definitely use the steady flow analysis. For any channel or river reach you can assign a number of flow profiles, as different flow scenarios. By this way you can see the stage in the channel at various locations and also get an initial idea of the conveyance of the channel. However unsteady flow analysis is different and it captures the temporal changes of flow and stage at different locations in the channel and is not replaceable by steady analysis. But in case of scarce data your idea should fit in.

Good @Bachir