STUDY ON FLOOD HAZARDOUS ZONES IN URBAN AREA FROM THE VIEW OF LOCAL INUNDATION DEPTH AND FLOW VELOCITY

Abstract

In this study, we focused on the dangerous zones from the view of local inundation depth, flow velocity and their increasing ratio. A simulation model of two-dimensional inundation flow analysis is applied to the highly urbanized area around the Nakashima River, Nagasaki City. As the results, the whole computational area can be classified into three categories of dangerousness depending on inundation depth and flow velocity. And from the temporal change of inundation depth and flow velocity at several spots, it is found out that there are locally dangerous zones where flow velocity quickly increase while inundation depth is not so large.