Author(s)

P. Archambeau, B. Dewals, S. Erpicum. T. Mouzelard & M. Pirotton

Abstract

Gradual dam breaching is an important factor that should be included in an embankment break model. Indeed the assumption of instantaneous break is not suitable in case of earth dams, which fail gradually and thus induce a delayed peak outflow, significantly reinforcing the flood wave front. Unlike computations performed classically, WOLF software package deals with the different phenomena (erosion processes, reservoir emptying and downstream wave propagation) in a completely integrated way. This finite volume computer code has been completely developed by the authors at the University of Liege. Transient discontinuities are properly handled thanks to an original splitting of the convective terms. The paper briefly presents WOLF software, which includes a physically based hydrological model, an original 1D flood routing (appropriate for any natural river network) and a 2D shallow-water solver. The latest hydrodynamic model is coupled to a mass balance for bed load sediments. Solid discharges are evaluated with reliable transport capacity laws. Gravity induced solid discharges are taken into account by means of side slope stability analysis. This paper also exhibits how WOLF software package has been successfully applied to the completely coupled computation of a gradual dam breaching process, with a focus on downstream effects on wave propagation. WOLF proves its ability to achieve the integrated computation of solid transport, flows upstream, through the breach, in the scour hole and in the whole downstream valley. Major feedback effects on the upstream part of the reservoir are shown and they demonstrate the relevance of such an integrated approach.

Keywords