Hello,
I am trying to model backwater effects from a larger stream into a 2D mesh which already has two sources of upstream inflow. Typically, in 1D models, the downstream boundary condition can be set to a known water surface elevation to account for backwater effects. In the case of 2D models, where an outflow boundary condition is required to allow for the inflow to leave the mesh, how can backwater effects be accounted for at the downstream extent of the 2D mesh?
If the downstream boundary conditions is set to a stage hydrograph of the backwater elevations, the upstream inflow will have no outflow and it will start to build up in the mesh. The ultimate goal is to run flow from the incoming streams, and any WSEL which is less than X-ft, is set to X-ft to be in the backwater.
Any help would be appreciated!