Dam breaching models: testing the influence of the erosion parameters

André Paquier

Tuesday 30 june 2015

15:05 - 15:20h at South America (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Flood risk assessment

Parallel session: 6J. Floodrisk - Assessment

Earthen dams can be overtopped during extreme events that reach flow discharges above the design discharge. Breaching models can simulate the erosion of the embankment and can be coupled with 1-D or 2-D shallow water equations for propagating the dam break wave. Alternatively, sediment transport models can be used for both processes. In order to evaluate the influence of the choice of the model and of the main parameters of each model, two series of tests are used. The first ones concern one field test including a 6 m high embankment; the second ones deal with laboratory experiments in which the embankment height is about 0.6 m. Comparing the flow hydrograph at breach site, the higher differences come from the calculation method of the erosion rate or more simply from the value of the erosion coefficient. However, for the selected experiments, these differences are essentially outside the period with high velocities which means that the peak discharges are very similar and that the main differences are found in the evolution of the breach shape leading, for instance, to very different final breach widths.

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