Empirical Methods For The Estimation OfDebris Flow Deposition Areas

Debris and hyper-concentrated flows are among the most destructive of all water-related disasters and in recent years have attracted more and more attention from the scientific and professional communities and concern from public awareness, due to the increasing frequency with which they occur and the death toll they claim. The study of debris flows can be subdivided into three main topics: assessment of the magnitude of the phenomenon; study of debris flow motion; determination of the extension of the deposits. This last issue is of paramount importance from an engineering point of view, due to the fact that it determinates which areas must be considered at risk, with all the consequences linked to the protection of population, and the predisposition of safety plans concerning different activities such as building construction. In this paper, a review of the most important empirical procedures of prediction of depositional areas is presented, with the aim to verify the applicability of the formulas to events different from those for which the methods were calibrated, and then to try to unify them, in order to originate a more reliable methodology. Laboratory tests were carried out to integrate the data available in literature. The experimental data have been recorded with photogrammetry methods and 3D models of the deposits have been designed and validated. The proposed empirical method will allow us to improve both mitigation measures and hazard mapping procedures.