Estimation of the Risk on Compound Water Related Disaster

Abstract

 This study makes the simulation of a compound disaster involving flood and storm surge and evalu-ates the damage cost for the disaster in Japan. The tide level and daily rainfall, which cause the com-pound disasters, are calculated by means of frequency analysis for annual minimum atmospheric pres-sure. 2D non-uniform flow model expressing the inundation depth is carried out using the tide level data on coastline and daily rainfall distribution interpolated as input data. Damage cost is estimated using the inundation depth by each land use. The annual expected damage cost of flood in whole Japan is 1.1 tril-lion JPY, that of storm surge is 468 billion JPY, and that of compound disaster is 778 billion JPY. In 38 prefectures out of 46 prefectures of Japan, the damage cost of only flood is larger than that of only storm surge and the compound disasters.