An integrated approach for assessing debris flow hazard at regional scale

Within the framework of the EC-project DAMOCLES (Debrisfall Assessment in MOuntain Catchments for local End-userS), debris flow hazard was assessed by both black-box and physically-based approaches in a pilot area (Valsassina) of the Italian Alps. The first incorporates a large set of geo-environmental variables, such as rock type, land use, and very detailed morphometric attributes of slope and channel in a multivariate statistical function. The second is based on the SHETRAN basin scale landslide erosion and sediment yield model. The two techniques for estimating debris flow occurrence were compared highlighting their respective potentials and drawbacks. Subsequently, an attempt was made to develop an integrated approach for predicting debris flow occurrence in both space and time. The results of the investigation indicate that, by integrating the two models, the effects of possible scenarios of future climate and land use on debris flow susceptibility within a catchment can be evaluated.