Abstract
Numerical simulations of flood flow in the Onga river basin and inundation flow in the Iizuka-city area due to torrential rain were performed by a numerical model for rainfall-runoff in watershed and flood inundation process in urban area with flood disaster-reduction system such as sewer network and drainage pump station. The rain-fall runoff, flood flow in rivers and inundation flows on the ground and free-surface-pressurized flow in the sewer network were simulated by a distributed hydrological model, the 2D free-surface flow model and dynamic network model for free-surface-pressurized flow combined with the Preissmann slot respectively. The characteristics of flood flow and inundation flow in Iizuka-city in the Onga river basin due to several torrential rain were examined based on the numerical results.
