An Efficient and Modular Approach Dedicated to Dam Breaks

Résumé En

The paper presents an integrated tool for dam-break hazard modelling. It is based on a two-dimensional, depthaveraged hydraulic model that uses a conservative and shock-capturing finite volume scheme on a Cartesian grid. The hydraulic model is designed so that different zones within the computation domain can be modelled with different spatial resolutions and/ or different model enhancements (e. g. pressurized flows, sediment transport etc.). The twodimensional model can be coupled with lumped models that compute the water stage in reservoirs and the outflow discharge through hydraulic structures in case of normal operating, failure of a valve or breaching processes. These features make hydraulic modelling versatile and computationaly efficient. They enable the definition of different failure scenarios, which is of prominent importance given the uncertainty of such a phenomenon. If several hydraulic structures are involved, the procedure takes the behaviour of each structure into account. The sensitivity of the results with respect to the interactions between the flow and the terrain (roughness coefficient, collapse of buildings, breaching process) can be analysed. The results of the hydraulic model are handled thanks to a graphical user interface that provides one-, two-and three-dimensional views and animations of the unsteady flow field and enables the understanding and verification of the results. Danger maps are generated based on the results of one or more ‘ worstcase’ scenarios. In case of a complete risk analysis, the danger maps are combined with data on the exposure and vulnerability of elements at risk for the computation of the corresponding damage.