CONSIDERATIONS ON EXPRESSION OF FLOOD HAZERD MAP IN INUNDATION AREAS AT URBAN DISTRICT

Abstract

 In Japan, the flood hazard maps have been established and have been distributed to residents in order to reduce dameges due to severely floods by the regional governments. However, the inundation depth is utilized for the expression on present flood hazard maps mainly. Actualy, as the inundation has accompanied with flow velocity, these is a strong possibility that the evacuees can not walk in the inundation area even if small water depth. On the other hand, in the case of the inundation by slow degree, as it is considered that the evacuees by walking can not become aware of underwater objects which are a curbs steps, ditchs and so on in muddy flood water, the ambulation in muddy water will endanger evacuees. Therefore, it is considered that the expressions of present flood hazard maps in Japan are insufficient. In this study, the point of insufficient expression for present flood hazard maps is indicated. Also, the method of expression to improve present flood hazard maps is investigated.