Author(s): Naoki Fukuoka; Hiroki Takaoka; Hiroyuki Nagano; Haruyuki Hashimoto
Keywords: No Keywords
Abstract: There occurreda number of landslide-induced debris flows in the mountain area of Hiroshima City during the heavy rain on August 20,2014. The debris flow in the Ueyama River produced serious damage to many houses in the downstream residential area. The numerical simulation was performedfor the debris flow. Six basic equations were used in this simulation; they are the momentum equation, the continuity equations of liquid, solid and wood phases, and the equations of erosion rate of river bed and side. There are six unknown quantities, such as flow discharge, flow depth, sediment concentration, driftwood discharge, riverbed elevation, and river width. The simulation results showed thatthe peak flow discharge is 520m 3 /sec at the river mouth. The peak flow depth and velocity was 4.1 m and 15 m/sec. The total outflow of sediments and driftwood was about23,000 m 3 and 470 m 3, respectively.