Abstract
This study presents a flood damage prediction model and a risk analysis method for flood protection level decision. The flood damage prediction model is composed of two models: a flood inundation prediction model (Model 1) and a flood damage estimation model (Model 2). Model 1 calculates the inundation depths of a river basin for any given storms. Model 2, using the depths obtained by Model 1, computes the damage amounts of the private properties as a function of inundation depth. In the calculation process, we fully utilize GIS as a tool for the damage calculations. The models were applied to flood damage simulations for the Kanda river basin with highly urbanized catchment located in the Tokyo Metropolis. The simulations yielded the flood damage for a set of several storms with different return periods. With the calculation results, we carried out a risk analysis for flood protection levels of the Tokyo metropolitan goverment and proved that the protection level is reasonable and acceptable for engineering viewpoint.
