SIMULATIONS OF URBAN INUNDATION AND DRAINAGE PROCESSES IN A HILLY URBAN AREA

The inundation and drainage processes in a hilly urban area where a steep urban river, with complicated geometry and hydraulic structures, flows through are investigated by the 2D inundation model, which comprises the finitevolume method with unstructured grid and flux-difference splitting (FDS). The flood flow in the river and inundation flow in the urban district are solved simultaneously by the model in order to evaluate overflow discharges from the river as precisely as possible. The inundation and drainage processes along with the roles of the overflow discharges, sewerage system and overland flows due to rainfall in the inundation and drainage processes of the district are identified for measures of the mitigation against flood disasters.