ASSESSMENT OF THE RISK ON FLOOD AND STORM SURGE WITH FLOOD CONTROL FACILITIES

Abstract

 This study makes the simulation of a compound disaster involving flood and storm surge and evaluates the damage cost for the disaster in Japan. The tide level and daily rainfall, which cause the compound disasters, are calculated by means of frequency analysis for annual minimum atmospheric pressure. 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 4.04 trillion JPY, that of storm surge is 4.04 trillion JPY, and that of compound disaster is 3.89 trillion JPY. In 31 prefectures out of 46 prefectures except for Okinawa prefecture of Japan, the damage cost of only flood is larger than that of only storm surge and the compound disasters.