Cost-Benefit Analysis of Disaster Mitigation Infrastructure: The Case of Seawalls in Otsuchi, Japan

Disaster management problems often pose the same types of challenges that environmental governance problems do; they involve decision-makers at various levels and can transcend political boundaries. We conduct a benefit-cost analysis of a disaster adaptation strategy in Otsuchi, which was undertaken shortly after the 2011 Tohoku earthquake and tsunami devastated the region. Results indicate that present value net benefits from the planned seawall are positive, even if expected damages are low, provided that the wall is capable of reducing damage by at least 50%. A hybrid method of governance may, however, be effective at increasing the benefit-cost ratio.