I’m helping one student to Dam break analysis of a dam using HEC RAS 5.0.1.
We have modeled Dam with spillway (as a weir). When we specify water level (2-3m) above the spillway crest model doesn’t take it and it runs simulation from weir crest level.
It sounds like the WSEL of the simulation never reaches 2-3 meters above the spillway crest, and therefore no breach is triggered. 2-3 meters (6-9 feet) above a weir is quite significant. A piping failure trigger can be used instead of an overtopping WSEL trigger.