Risk management in urban areas forces politicians to make sensible decisions on problems that they normally poorly understand. A decision support from technicians is therefore essential for good management, and should be addressed to the identification of different scenarios in terms of potential damage and probability of events. A 1.2 million m3 debris avalanche failed in December 2002 on the village of Bindo (Cortenova, Italy), destroying 17 houses and interrupting industrial activities for several weeks. Fortunately, no lives were claimed. A large portion of slope is still active and threatens the remnant part of the village. Considering both the characteristics of the landslide and the socio-economic settings, we identified three possible mitigation strategy: (1) the construction of a large defensive work in front of the potential landslide; (2) the long-term displacement monitoring of the unstable sector of the slope, with a related alarm system; (3) the combination of (1) and (2). The three scenarios have been also compared with a hypothetical zero-scenario, without any mitigation action introduced. In order to provide support to politicians and to identify the mitigation strategy with the lowest cost/benefit ratio, we performed a cost-benefit analysis of the different scenarios. For such analysis, we considered only the direct effects on human life, houses and lifelines. At the same time, we defined levels of social acceptance of landslide risk for the endangered community by means of questionnaires and socio-economic data. Thus, we evaluated the different scenarios on the light of acceptable risk levels and we found that, even with a large uncertainty, the best mitigation strategy would be the combination of the defensive works and the monitoring network.
Crosta, G., Frattini, P., Fugazza, F., Caluzzi, L., Chen, H. (2005). Cost-Benefit analysis for debris avalanche risk management. In Landslide Risk Management: Proceedings of the International Conference on Landslide Risk Management (pp.517-524). London : Taylor & Francis.
Cost-Benefit analysis for debris avalanche risk management
CROSTA, GIOVANNI;FRATTINI, PAOLO;
2005
Abstract
Risk management in urban areas forces politicians to make sensible decisions on problems that they normally poorly understand. A decision support from technicians is therefore essential for good management, and should be addressed to the identification of different scenarios in terms of potential damage and probability of events. A 1.2 million m3 debris avalanche failed in December 2002 on the village of Bindo (Cortenova, Italy), destroying 17 houses and interrupting industrial activities for several weeks. Fortunately, no lives were claimed. A large portion of slope is still active and threatens the remnant part of the village. Considering both the characteristics of the landslide and the socio-economic settings, we identified three possible mitigation strategy: (1) the construction of a large defensive work in front of the potential landslide; (2) the long-term displacement monitoring of the unstable sector of the slope, with a related alarm system; (3) the combination of (1) and (2). The three scenarios have been also compared with a hypothetical zero-scenario, without any mitigation action introduced. In order to provide support to politicians and to identify the mitigation strategy with the lowest cost/benefit ratio, we performed a cost-benefit analysis of the different scenarios. For such analysis, we considered only the direct effects on human life, houses and lifelines. At the same time, we defined levels of social acceptance of landslide risk for the endangered community by means of questionnaires and socio-economic data. Thus, we evaluated the different scenarios on the light of acceptable risk levels and we found that, even with a large uncertainty, the best mitigation strategy would be the combination of the defensive works and the monitoring network.
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