Dam-break modeling in alpine valleys

Dam-break analysis is of great importance in mountain environment, especially where reservoirs are located upstream of densely populated areas and hydraulic hazard should be assessed for land planning purposes. Accordingly, there is a need to identify suitable operative tools which may differ from the ones used in flat flood-prone areas. This paper shows the results provided by a 1D and a 2D model based on the Shallow Water Equations (SWE) for dam-break wave propagation in alpine regions. The 1D model takes advantage of a topographic toolkit that includes an algorithm for pre-processing the Digital Elevation Model (DEM) and of a novel criterion for the automatic cross-section space refinement. The 2D model is FLO-2D, a commercial software widely used for flood routing in mountain areas. In order to verify the predictive effectiveness of these numerical models, the test case of the Cancano dam-break has been recovered from the historical study of De Marchi (1945), which provides a unique laboratory data set concerning the consequences of the potential collapse of the former Cancano dam (Northern Italy). The measured discharge hydrograph at the dam also provides the data to test a simplified method recently proposed for the characterization of the hydrograph following a sudden dam-break.