RESUMO
In Japan, the need for investment in public works, including flood disaster prevention facilities, such as dykes and dams, is widely discussed at present. This paper aims to evaluate the comprehesive efficiency of flood disaster prevention investment from 1955 to 1999 by developing and applyng an evaluation model that focuses specifically on relative success in the prevention of human and economic losses. Results of our analysis have carified some important issues currently being discussed in Japan. Firstly, a one-way-layout analysis of variance shows there to be a statistically significant diffenrence only between the period of 1955-1961 and those of 1962-1967, 1968-1983 and 1984-1999. The average values of normalized flood losses decreased greatly between the 1955-1961 period an the 1984-1999 period. Secondly, the ratio of human loss to total loss caused by floods in Japan may be less than 10
. This ratio showed an increasing trend before 1970 and then stabilized at around 8
after 1970. The proportion of intangible effect to total loss increasedfrom less than 10
before the 1970s to aproximately 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, not only from the economic standpoint, but also fom thet of total flood loss saving. We conclude that is necessary to explore the usefulness of the new investments and to develop improved strategies for flood disaster prevention from a risk management viewpoint
