Assessment of the impact of sediment transport on roads in a Mediterranean environment

In Central Tuscany human activities have long experienced a problematical coexistence with natural processes finding nonetheless, during the last two centuries, a quasi-stable equilibrium. This last is today somewhat disturbed when natural hazards and human infrastructures overlap, In the study area, Virginio watershed, which summarises the average environmental characteristics of the whole Chianti region, one of the most critical issues is represented by the intersection between roads and mass movements. This aspect assumes here a notable importance because on the one hand landslides are very common in the area and on the other hand the roads have a high economic and strategic value since they represent the only way in and out of the watershed. We propose here a simple and easy to apply landslide risk assessment model able to predict the possible short-term landscape evolution scenarios. In particular, in a customised GIS environment, information on road damage recurrence intervals was collected and stored as well as data on landslides classification and inventory. The joined elaboration of these data, together with information on the economic costs of the restoration and prevention efforts deployed by the local governmental agencies in the last twenty years, allows for a correct evaluation of the cost-benefit ratios. This in turn represents a valuable tool for the optimisation of the territorial planning policies in the whole region.