A multi-scale approach to cost/benefit analyses of landslide prevention vs. post-event actions.

Abstract

The main aim of this paper is to test economic benefits of landslide prevention measures vs. post-event emergency actions. To this end, small and large scale analyses were performed in a training area located in the North-Eastern Italian pre-Alps that was hit by an exceptional rainfall event occurred in November 2010. At the small-scale, landslide susceptibility was initially assessed using a simple probabilistic analysis, which allowed to highlight the main landslide conditioning factors and the most hazardous areas. However, this approach revealed to be quite insufficient to reach planned goals, so a large-scale case-by-case analysis was performed: a study case was defined, accord ing to landslide occurrence frequency and assessment of elements at risk. Numerical modeling demonstrated that remedial works carried out after the landslide - waterremoval intervention such as a drainage trench - could have improved slope stability if applied before its occurrence. Then, a cost-benefit analysis was finally employed. It defined that prevention would have been economically convenient compared to a non preventive and passive attitude, allowing a 30%saving relative to total costs. Therefore, this kind of approach could be actually used as a mean toward preventive soil protection not only within the investigated case study, but also in all those hazardous areas where preventive measures are needed. [ABSTRACT FROM AUTHOR]