Aumento dell'affidabilità e dell'efficienza del modello DFRM per simulare al propagazione di colate detritiche.

In the upper regions of mountain basins, landslides play a fundamental role in shaping the terrain and supplying sediment to channel flow. Within this frame, numerous processes must be considered, which include to rock collapses to sediment flow dynamics in the principal channels. Among the various types of landslides that can occur along these channels, one of the most perilous is the debris flow, a rapid surge of sediment and water mixed. Due to the flow's speed and its ability to transport big boulders at its impact front, debris-flows possess a high destructive potential. Other significant hazardous factors include the long distances they can cover and their sudden occurrence, sometimes without previous runoff in a channel. Triggering occurs when there is a right combination of three main conditions: the channel slope; the runoff and the availability of sediment at the channel bottom and its susceptibility to movement. When runoff impacts sediment in the area where the channel slope is above a threshold, a debris flow may be triggered. However, the presence of sediment in the channel bottom is necessary for a triggering and closely linked to landslides occur in upper part of basin. Therefore, the connectivity of the sediment on basin’s slopes is important to the initialization of the flow transport. Consequently, debris flow is a natural phenomenon that is not easily predictable because local channel conditions are influenced by several processes. In addition, estimation of runoff through a hydrological model is not easy task, it requires right calibration using a good knowledge of the study area and a correct identification of the local rainfall volume. Sometime, these latter points are not easy to achieve in particular way in mountainous area. All of these concepts underscore the importance to study and developing models that help authorities in predicting and identifying the risk to human lives and activities. Especially because, areas with small slopes in the centre of the valley were considered the most suitable place to build, but sometimes these are deposition fans formed by sediments from debris-flow events. Nowadays, numerical models are the main tools for identifying hazards and assessing risks. They play a crucial role not only in new project development but also in evaluating the effectiveness of existing countermeasures. Moreover, improving the knowledge on debris-flow initiation and propagation and their modelling becomes very important to reduce and control the risk in the subject area. The final goal of this research is to develop an efficient and reliable model that can be used both in the aforementioned fields and integrating in a model base early warning system.