Scenari di rischio e sistemi di supporto alle decisioni per la gestione delle emergenze idrogeologiche

The aim of the work in this PhD project is to perform a hydrogeological risk analysis that can be an useful management tool for Civil Protection and policy makers to take decisions about environmental planning. The study has been conducted in the Mountain Consortium of Municipalities of Valtellina di Tirano. The area is located in Sondrio province and it is composed of twelve municipalities, covering a global area of 450 km2. The majority of municipalities lie on alluvial fan and along Adda River. The conformation of the territory is the cause of the high vulnerability of Valtellina Valley, mainly linked to landslides and hydrogeological events. This situation is made worse by anthropic alterations, for example building in highly risk zones, deforestation and low slope maintenance. In the first part of the study an institutional hydrogeological risk map of the area is elaborated following guidelines policy of Lombardy Region. Then, this map has been compared with a second debris flow risk map, derived by two probabilistic and statistical models: the Weights of Evidence model has been used in order to obtain a susceptibility map (debris flow source area), whereas Flow-R model generated an hazard map (runout). Finally, probable risk scenarios (critical zones with high hazard levels and elements at risk) have been defined. After their identification, the emergency procedures of Civil Protection have been elaborated using DSS (Decision Support System) and linked to a large territorial database (resources and structures). These procedures consider the actual availability of structures and resources in the study area in order to appreciably shorten the operation time of Civil Protection activities in case of emergency. This approach leads up to computerize and speed up the reply of the structures involved in an emergency situation, leading to a significant reduction of the response time by the staff that manage the emergency operations, and leading to an increase of the qualitative efficiency response.