Author(s): Hiroki Takaoka; Haruyuki Hashimoto; Kichan Park; Shoichiro Kido; Makoto Hikida

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Keywords: Bed variation; Two-dimensional simulation; Landslide; Debris flow

Abstract: Minamata City in Japan had heavy rains on July 20, 2003. As a result, a large-scale of landslide occurred on right-hand side slope of a mountain river in Minamata City. The landslide changed into debris flow and moved down the mountain river. During the movement in the middle reach at steep slope, the debris flow eroded the river bed and bank and increased its flow discharge. In the downstream reach at mild slopes, the debris flow caused sediment deposition and moved over river bank. The debris flow did great damage to many houses and killed 15 people of the residents along the river. In order to measure such disaster we have to know the detail of the debris flow behavior. The purpose of the present study is to propose a debris flow simulation model for the mountain river and investigate the process of the debris flow disaster. We can see that the damage to the houses on the right-hand side of the river reach was serious because of the larger drag force.

DOI:

Year: 2005