FLOOD DAMAGE DUE TO DYKE BREAK IN IZUSHIGAWA RIVER IN 2004 BASED ON QUESTIONNAIRE AND NUMERICAL SIMULATION

Abstract

Recently, we have been severely damaged by dyke breaks of rivers due to typhoons or local heavy rains. In order to evaluate the flood damage by dyke breaks, it is important to consider flood flow and sediment transport at the same time especially for steep rivers that carry much suspended sediment. We develop a numerical method for flow and sediment transport on flood plains, which employs an explicit and conservative CIP scheme based on the control volume approach to directly capture the various conditions on the flood plains. The numerical method is applied to the actual dyke break occurred in October 2004 in Izushigawa River. The method is validated through the comparison between the numerical results and questionnaire results for house damages.