Risk assessment for hypothetical dam break A method for the rapid and consistent evaluation

This paper details the technical contribution to the theme of flood risk analysis as consequence of a dam failure. According to the numerical problem proposed for the workshop, the analysis consists of the evaluation of the dam break and its consequences. The simulation includes two scenarios of dam breach: the scenario 1 that represents the case of an easy erodible dam and the scenario 2 the case of an erosion resistant dam. For each scenario, a dam failure discharge hydrograph was calculated and the subsequent flood wave and consequences have been evaluated. The methodology adopted involves, for a first part, the use of standard models for the hydraulic modelling of the dam breach and flood wave propagation. For the second part, a set of GIS scripts was written, tested and developed using the python scripting language to obtain a rapid appraisal of consequences for the population and to assess the direct economic damages for residential, commercial, and industrial buildings. Since the latter elaboration depends greatly on the type and the level of detail of available data, in this study we have been used data as generic as possible and GIS scripts that allow, for a great variety of cases, a rapid initial assessment.