An Empirical Model of Efficiency Analysis on Flood Prevention Investment in Japan

This paper aims to evaluate the comprehensive efficiency of flood disaster prevention investment from 1955 to 1999 by developing and applying an integrated evaluation model. Our analysis results have clarified some important issues currently being discussed in Japan. Firstly, the average values of normalized flood losses decreased greatly between the 1955-1961 period and the 1984-1999 period. Secondly, the ratio of human loss to total loss caused by floods in Japan may be less than 10%, based on the concept of the value of statistical life (VOSL) and values estimated from the risk-money tradeoff. The proportion of intangible effect to total loss increased from less than 10% before the 1970s to approximately 20% after that period. Finally, flood prevention investment in Japan effectively reduced losses caused by flooding before the 1960s; however, since the 1980s, investment has changed from an efficient mode to an inefficient mode, not only from the economic standpoint, but also from that of total flood loss saving.     

Factors determining residents’ preparedness for floods in modern megalopolises: the case of the Tokai flood disaster in Japan

This study examines how flood risk perception and home ownership affect residents’ preparedness for floods, focusing specifically on the case of the Tokai flood disaster in Nagoya City, one of Japan’s biggest metropolises, in 2000. The greatest rainfall ever recorded in Nagoya City (566.5 mm) occurred on 11–12 September 2000; as a result, a local river burst its banks and flooded the city. A survey was conducted of residents of the affected area in Nagoya City and its adjacent region. The respondents were asked to rate the extent of their experience with, anticipation of, and preparedness for floods before and after the Tokai disaster in terms of taking special measures against floods. The results showed that the degree of preparedness for floods was determined by the level of fear of floods and the amount of damage sustained during the Tokai flood, especially for homeowners. However, the residents’ preparedness did not depend on their anticipation of floods. These findings show that preparedness for floods depends on ownership of a home, fear of flooding, and the amount of damage from previous floods rather than on previous experience with and anticipation of floods.