Assessment methodology for the prediction of landslide dam hazard

This paper represents a contribution to the study of hazard caused by the interaction between landslides and river courses. The effects of such interferences are often catastrophic and could include the formation of backwater lakes, potential dam failure, river bed dynamics and morphological alterations. These scenarios could be substantially reduced if it was possible to predict the eventuality that a moving landslide could block the river. This is a complex topic because it involves composite geomorphic phenomena concerning both hillslope and river systems and their interpretation, through model approaches, is still under development and testing. In this study, a methodology developed in the framework of the European Research Project IMPRINTS (FP7), was adopted and integrated in order to identify the areas of triggering and propagation of landslides and to characterize the possible scenarios of the interaction with river networks. Different deterministic and probabilistic approaches, calibrated using a case test in the middle valley of Noce River in Basilicata region (Italy), were applied and compared at basin scale. In this area, a landslide mobilized in July 2007 on the right side slope of the river invaded a gravel-bed reach, characterized by a narrow and confined section, causing its progressive morpho-hydrodynamic change.