Estimating the Benefits of Flood Protection—Reviewing the Transition of the Cost–Benefit Analysis Manual in Japan and the Implementation Status of the International Flood Protection Project

Abstract

AbstractCost–benefit analysis is crucial for prioritizing and justifying disaster risk reduction projects. This study aimed to identify important issues in the application of various cost–benefit analysis methods. It reviewed the diverse evolving processes of these methods in Japan and examined their advantages and limitations. In Japan, cost–benefit analysis methods are commonly applied to investments in flood protection engineering projects to evaluate their benefits. Furthermore, the analysis also estimated the damage prevention benefits of river improvement and the river water level reduction benefits of dam construction. The assets in danger of being damaged included houses, factories, infrastructures, and short-term economic activities. However, estimating all the benefits generated by flood protection projects remains a challenge. For example, the benefits of saving human lives or mitigating long-term indirect costs have not been counted. Therefore, this study proposes some concrete directions in this regard for future studies.keywordsCost–benefit analysisInternational Flood Protection ProjectManual