Author(s): Hiroyuki Nagano; Haruyuki Hashimoto; Kesayoshi Hadano; Farouk Maricar
Linked Author(s):
Keywords: Debris flow; Numerical simulation; Flood area; Hofu City
Abstract: In this paper, we simulated the landslide-induced debris flows which occurred in the three mountain rivers at Ishihara district in Hofu City, Japan on July 21,2009. We estimated the flow characteristics in their upper river reach with the one-dimensional numerical simulation method and the flood characteristics in their lower river reach with the two-dimensional numerical simulation method. The one-dimensional numerical simulation discusses the effect of the landslide, river bed and side erosion on the outflow of sediment. Some different conditions of the landslides, such as their volume, duration time and sediment concentration, are assumed as the boundary condition of the one-dimensional simulation. These simulation results show that the peak discharge is 309,246 and 31 m 3 /s at Ishihara River A, B and C, respectively. The debris flows reach the residential areas with high sediment concentration and large velocity. The two-dimensional numerical simulation discusses the flood region of debris flows on the residential area. These simulation results show the excellent agreement with the aerial photos of the flood areas.
Year: 2012