Hi all,
I am setting up a hydrodynamic model for a large shallow lake (about 3000km2) with complicated bathymetry (-2~35m). The water level increases significantly in flood period, but decrease significantly in dry period, therefore, the vegetation types are various (eg. woods, carex, grass).
Discharge is used for upstream boundaries, and Water level is used for downstream boundary. Manning' M map is used in the model. For the Flood and Dry type, I selected Standard Flood and dry (Drying depth=0.005m, Flooding depth=0.05m, Wetting depth=0.1m ). The model can runs smoothly in flood year, the simulated water level at the downstream stations are good. But at the upstream locations, the water level is overestimated (sometime maybe 2m error) at low water stage while slightly underestimated at high water stage. Should I increase the Manning's M for the main waterbody and decrease M near the boundaries?
Another problem is that, in drought year, it has CFL problem even with the same setup files. I tried to decrease the time step, but still didn't work. However, if I set the wetting depth to be greater than 0.8m or select Advanced flood and dry (floodplain) and set the wetting depth to be 0.5m, the model works smoothly. But just like those during low water level period in flood year, the water level are overestimated except for those downstream locations.
Thanks for all the help.
Regards,
Katherine
