Dam-break flows over mobile beds: experiments and benchmark tests for numerical models

In this paper, the results of a benchmark test launched within the framework of the NSF-PIRE project "Modelling of Flood Hazards and Geomorphic Impacts of Levee Breach and Dam Failure" are presented. Experiments of two-dimensional dam-break flows over a sand bed were conducted at Universite catholique de Louvain, Belgium. The water level evolution at eight gauging points was measured as well as the final bed topography. Intense scour occurred close to the failed dam, while significant deposition was observed further downstream. From these experiments, a benchmark was proposed to the scientific community, consisting of blind test simulations, that is, without any prior knowledge of the measurements. Twelve different teams of modellers from eight countries participated in the study. Here, the numerical models used in this test are briefly presented. The results are commented upon, in view of evaluating the modelling capabilities and identifying the challenges that may open pathways for further research.