Experimental Study on Effect of Houses on Debris-Flow Flooding and Deposition in Debris Flow Fan Areas

Kana Nakatani, Megumi Kosugi, Yuji Hasegawa, Yoshifumi Satofuka and Takahisa Mizuyama

This study conducted model experiments to determine the influence of houses on debris flow flooding and deposition. We applied uniform and also coarse-grained sediment in the following scenario cases: without houses; with houses; with houses and fences; and with houses that can be destroyed. The model experiments showed that when houses are present, the debris flow spreads widely in the cross direction immediately upstream of the houses. Houses located in the debris fan also influence the deposition area. Especially when fences exist around the houses, flow moves down between the fences, as in the real disaster cases, where flow moves down towards the roads. Finally, when houses are destroyed, flow moves down through the destroyed houses, and changes the flooding and deposition process compared with the non-destroyed houses case. With debris flow containing coarse-grained sediment, most of it deposits in the upstream area of the houses when houses exist.

2016/1 378-386