Hello!
First time HECRAS user here. I am modeling a tributary that discharges into a large river system as a 1-d model, with the goal being to get flow magnitude and direction at the confluence of the two systems.
I have the larger river modeled as an upper and lower reach, and the tributary enters and meets at the junction point. When I run my model, the flow and stage hydrograph is similar to observed conditions for the larger river; however for the small tributary, the hydrograph is completely unreasonable. It’s as if the larger river is the only driving force, and it is using the smaller trib as a floodplain almost (the water elevations of the trib are never in the channel (even at low flow) and always about the same height as the large river). I have established ineffective flow areas around the larger river, but it did not change any of my output.
Was wondering if this has happened to anyone else, or if anyone has any solutions as to why this might be?