Abstract
The inundation process in urban area was investigated numerically in the present study. The numerical simulation model was developed by coupling the following three sub-models; the model of overland flow on the road network, the model of flow in drainage network and that of the flow in underground space, respectively. The water exchange among these three sub-processes is the key point to be handled reasonably in this kind of model. As a result of some series of numerical simulations, the effect of drainage network on the inundation damage itself was understood quantitatively. In case of downtown Shinjuku, the severe inundation damage is expected to occur in both an underground space and some local areas where the ground level is much lower than any other region here under the heavy rainfall even if the drainage network works effectively.
