Evaluating Disaster Mitigations: Methodology for Urban Infrastructure Systems

Abstract

This paper develops a methodology for evaluating the benefits and costs of disaster mitigation measures for urban infrastructure systems. The methodology is distinguished in three respects: first, it demonstrates how life cycle cost analysis, a method often used in infrastructure management, can be extended and applied to the disaster context. Second, it demonstrates the importance of considering changes over time—including infrastructure deterioration, future maintenance costs, and urban growth. Finally, it emphasizes evaluating societal impacts. This is particularly important for lifeline infrastructure systems, where the benefits of mitigation investments accrue broadly to users or society as a whole. The methodology is applied to a case study of seismic risk for the Portland, Ore. water delivery system. Societal losses from earthquake are found to outweigh utility agency losses by 100 times. Two mitigation alternatives are compared with the option of no mitigation. In one case, a mitigation that is not cost-effective for the utility agency is shown to be very cost-effective from a societal standpoint. Further data and research needs are also identified.