Quick estimate of flood risk downstream a dyke breaching Methods and first stages of validation

Abstract

The risk caused by the flooding due to a breach across a dike along a river is established with recent disasters (floods in 2002 and 2003 : Gard, Vidourle, Rhône...). One of the main difficulty to assess this risk stays in defining where the breach will occur. To investigate a lot of locations, a simplified method is developed to represent all the processes : dike breaching and fl ood propagation downstream the dike. In this paper, the corresponding calculation methods are detailed and preliminary validation tests are presented.