>1. If the given breach width and side slopes implies a breach opening that extends outside the given cross section geometry of the dam, does DAMBRK restrict the opening of the breach to the cross section geometry ?
No it does not.
>2. I have a situation in which a dambreak wave enters a reservoir that has one large rockfill dam (90 m), an arch dam (35 m), four medium rockfill dams (2x20, 24 and 30 m) and 3 minor dams (1 rockfill and 2 gravity dams). These dams breach approximately at the same time, but still the reservoir will rise until the breach openings are large enough to give an outflow larger than the inflow. In order to compute this I need to take into account all the different breaches.
>The problem is that these dams have different failure times: The large rocfill dam has 1,2 hours of failure time, the arch dam fails momentanously, the medium r.f. dams has ca. 3 hours failure time, and the minor dams works as weirs.
>I have made a first attempt by modelling the large rockfill dam. Here I have specified a dambreak time of 1,2 hours. I have put the flow throuht the opening of the arch dam into the timedependent turbine discharge. The other dams are regarded as weirs and put into the spillway rating curve. This has two serious limitations. The turbine discharge is stopped by the program 0,6 hours after the dambreak has started (half the dambreak time), the breach of the medium rockfill dams are not simulated.
>Do you know how I can model this situation better ?
When a dam failure occurs, about half way through the simulation the turbine flow ends at the dam that was specified to fail. This is how DAMBRK is formulated.
The breach in the rockfill dams failed to occur because the water surface elevation never reach the specified elevation that it was to fail at. You will need to lower that.
Sincerely,
Chris E. Maeder, M.S.
Senior Technical Engineer
chrism@bossintl.com
Linear Mode
