open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

you can imagine, that the necessary boundary conditions in the numerical model are circa the same as if you are doing hydraulic calculations by hand. So, depending on the hydraulic conditions (subcritical or supercritical) at the open boundaries you should set the appropriate type of boundary condition for the inlet and outlet, respectively.
You can prescribe a constant elevation for a boundary if you know, that it will not change during your simulation, e.g. if you want to achieve a steady state flow field. E.g. if you want simulate a flood event, the water level at the outlet varies, so you should set a stage-discharge relation or a water level hydrograph.
Yes, initial depth = some value says that at t=0 you have this value everywhere in the domain. You can define a space varying inital depth in the subroutine condin.f (see the test case which submitted some forum posts before) but also in BlueKenue. Likewise you can set the rigid bed in the subroutine noerod.f, see also my submitted test case.
The test case is nearly the same as the Telemac example Ritter.
One other remark: seeing your sistest.cas file you have some keywords for suspension load transport. I would start with bed load transport modeling only.

Best regards,
Clemens