The RES approach for debris flow susceptibility analysis: A case study

Climate change has increased the occurrence and magnitude of debris flow events, especially in mountain areas. Moreover, their unpredictability requires to develop reliable methodologies for the evaluation of debris flow susceptibility, which is the starting point for risk assessment and management. In this paper, a modified version of the Debris flow Propensity Index (DfPI) is developed for the debris flow susceptibility estimation at basin scale. Bedrock lithology, fracture network, quaternary deposits, slope angle, channel network, and land use were identified as debris flow predisposing factors and were indexed by using open-access data and geodatabases. The objective of the proposed study is to develop a simple and economic procedure for the susceptibility estimation, easily to implement in GIS-based software for further analyses, such as propagation simulations or hazard scenarios, useful for planning mitigation strategies. The Canè Valley, a small valley located in the more famous Camonica Valley, (Lombardia Region, Northern Italy), was used as a case study for developing and testing the proposed approach.