A comparative 2d modeling of a debris flow e outcomes for end-users

Alpine debris flows endanger settlements and human life. Mitigation strategies based on hazard maps are necessary tools for land planning. These maps can be made more precise by using numerical models to forecast the inundated areas after carefully selecting those ’key parameters’ (K-P) which directly affect the flow motion and its interaction with the ground surface. Several physically-based 2D models are available for practitioners and governmental agencies, but the selection criteria of model type and of the related K-P remain flexible and partly subjective. This remark has driven us to investigate how different models simulate different types of debris flows (from granular to muddy debris flows, going through intermediate types), also in cases of flows influenced by the presence of check dams and deposition basins. The main aims of the study are i) to evaluate the performances of two commercially-available models to simulate different types of debris-flows, different volumes and the capacity of simulate mitigation measures like check dams and retention basins, ii) identify a procedure to calibrate the key model parameters and define the input data, iii) identify a synthetic simple index that permits evaluation of model performance