Suitability of the diffusive model for dam break simulation: Application to a CADAM experiment

Extreme hydrologic events are increasingly investigated and numerically simulated by means of complete 2D Shallow Water Equations (SWE). While the efficacy of this conceptual model has been proven several times, its numerical integration needs accurate schemes that still require an amount of computational effort. The use of less precise numerical methods does not justify the complexity of the full dynamic SWE model as they lower the overall correctness of the prediction. An approximation of the full SWE consists in neglecting the inertial terms, degrading the original hyperbolic to a parabolic model (PSWE). The effects of such a choice on simulating real flooding events are still not clear. Several conclusions are drawn in this work investigating the behaviour of a parabolic model compared to experimental data taken from Toce physical model. It resembles a dam break event in a steep valley, in which many transitions across critical flow together with multiple reflections occur and whose dynamic is not fully described by the PSWE model. Conclusions are taken on the reliability of conceptual model on the one hand, and on effectiveness of numerical scheme used to integrate it.