Dam Break in HydroCAD
Dam Break in HydroCAD
(OP)
I have modeled a watershed that drains to a lake. This lake has an earthen dam and a control structure. I am interested in breaching the dam, for inundation study purposes. The model is not very complicated, as the water shed is about 6 square miles.
The HydroCAD support site describes the method to perform a dam break, by setting the starting elevation of the lake to the peak elevation without the breach, and starting the calculations at the time when the breach occurs.
The problem that I have is that I don't see a way to input the time to failure. The method as described seems to just start the computations assuming that the breach is fully developed at the peak, when in fact, the breach develops over time. In my case, the time to failure is 30 minutes.
My breach model has really high discharges, which seem completely unreasonable to me. I think that the peak discharges should be lower if the breach takes time to develop, as compared to an instantaneous breach.
Any suggestions, ideas, comments...?
The HydroCAD support site describes the method to perform a dam break, by setting the starting elevation of the lake to the peak elevation without the breach, and starting the calculations at the time when the breach occurs.
The problem that I have is that I don't see a way to input the time to failure. The method as described seems to just start the computations assuming that the breach is fully developed at the peak, when in fact, the breach develops over time. In my case, the time to failure is 30 minutes.
My breach model has really high discharges, which seem completely unreasonable to me. I think that the peak discharges should be lower if the breach takes time to develop, as compared to an instantaneous breach.
Any suggestions, ideas, comments...?





RE: Dam Break in HydroCAD
Using this approach, you need to set the calculation time span to begin at the time of the fully-developed breach. There is no separate setting for the breach time.
The next HydroCAD release is expected to have a new "dam breach outlet" which will allow for a progressive breach, as well as setting the breach time independently of the calculation time span.
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Dam Break in HydroCAD
RE: Dam Break in HydroCAD
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Dam Break in HydroCAD
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Dam Break in HydroCAD
A scenario could be modeled varying the shape of the weir (breach) with time, thus modeling the discharge over a likely time period. Seems to me like a reduced scale model of the dam could be constructed to see the likely progression of failure weir shapes and times.
Mike McCann
MMC Engineering
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