Session1: River Engineering and Management

1-7

Title: EFFECT OF EXISTENCE OF HOUSES ON INUNDATION AREA OF DEBRIS FLOW

Hidetoshi Nakamoto, Hiroshi Takebayashi, Masaharu Fujita

It is expected that the number of occurrences of debris flow will increase due to the effects of global warming, in residential area, it is required to understand the flow characteristics of debris flow. In this study, two dimensional debris flow numerical simulation considering destruction process of houses is performed and effect of houses on the inundation area of debris flow is discussed. The simulated debris flow was occurred in Yagi 3 Chome, Asaminamiku, Hiroshima, Japan in 2014 and it destructed a lot of houses. The developed numerical analysis model can reproduce the horizontal distribution of complete/partial destruction of houses. If the houses in the inundation area are neglected, debris flow spreads widely and forms debris flow alluvial fan. As a result, the difference of inundation area between with house case and without house cases becomes large. This information must be important for evacuation act, when it is difficult to evacuate to far refuge under heavy rain conditions.