The model in the sharing server is showing that (pond-1) is flooding and that is shown in the HGL graph for scenario "FEH_50YRS 1440 MIN) when that scenario runs for 10 days, the problem that the pond is designed to handle around (527,000 cu.m) and the total volume generated from the model catchment to that pond is around (450,000 cu.m), meaning that pond should not show any flooding.
Another model "Test Pond Flood" which is also shared is created to double-check, where in this model the hydrograph has been copied from the last manhole (MH-2-1) in the original model and injected into the Test model, also other physical elements from the last manhole (MH-2-1) to the pond has been created in the new model, so the test model shows the expected results correctly and the (pond-1) is not flooded.
I re-run the original model with lower routing time steps (1 sec), but that does not change the flooding issue at the (pond-1).
This Graph from the original model shows the HGL reaches the top of the pond
This Graph from the Test model shows the HGL does not reach to the top of the pond
Regards,
Mohamad Azzam