Hi everybody,
I’m modeling the flushing operations of a reservoir on HEC-RAS 5.0.4. The dam is modeled as an inline structure and the bottom spillway as a gate, with the opening regulated by the water stage. The main goal of the simulation is to determine how much sediment from the bed of the lake goes through the bottom spillway, having a flow hydrograph as upstream boundary condition (unsteady simulation). I saw that different transport functions provide strongly different results in terms of sediment volumes moved. In my case, the grain size is very small (mainly clay and silty, 0.002 – 0.063 mm). I would highlight that I’m making simulations referring to single hydrological events (a few days) and that the lake is quite small. Does anyone know which transport function, sorting method and fall velocity method are the most suitable to these conditions?
Another issue: also the downstream river is modeled. If I change the erodibility of this reach, also the upstream results change. Can anyone explain this interaction?
thank you all for your help