Abstract
Flood damage cost was estimated based on numerical simulation with land-use category and the flood control economic research manual. The flood simulation was carried out by the distributed extreme precipitation data and the flood model in the whole country. The flood damages were assessed by the simulation results every return period and the flood damages calculation method. The results obtained are; 1) The inundation damage cost increases almost linear as the extreme precipitation increases, 2) When considering that the flood control measures to the extreme precipitation until the return period 50 years are completed, new measure costs are expected about 22 trillion yen to the probability precipitation of the return period 100 years, and 3) Similarly, when assuming the return period 30 years, the measures costs of about 36 trillion yen are needed.
