ECONOMIC LOSS ESTIMATION IN IIZUKA CITY USING NUMERICAL SIMULATOR FOR RAINFALL-RUNOFF/FLOOD INUNDATION PROCESS IN URBAN AREA WIT RIVER AND SEWER NETWORK

Economic loss estimations for flooding in the Iizuka-city area in the Onga river basin were performed using numerical simulator for rainfall-runoff in watershed and flood inundation process in urban area with rivers and sewer network. The rain-fall runoff was simulated by a distributed hydrological model. The flood flow in rivers and inundation flows on the ground were simulated simultaneously by the 2D freesurface flow model. The dynamic network model for free-surface-pressurized flow combined with the Preissmann slot was used for the sewer network. The economic loss estimation based on the simulated inundation area and depth was compared with the reported value. The effects of flood disaster-reduction system were also examined based on the numerical results.