| Co-Investigator(Kenkyū-buntansha) |
SATOFUKA Yoshifumi Disaster Prevention research Institute, Kyoto University, Instructor, 防災研究所, 助手 (20215875)
SAWADA Toyoaki Disaster Prevention research Institute, Kyoto University, Assoc.Professor, 防災研究所, 助教授 (60027258)
NAKAGAWA Hajime Disaster Prevention research Irnstitute, Kyoto University, Professor, 防災研究所, 教授 (80144393)
INOUE Motoyuki Tokyo Electric Power Co. Inc., Power Eng. R &D Center, Chief Researcher, 電力技術研究所, 主席研究員
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| Research Abstract |
This research aims to develop the methods 1) to predict the sediment delivery along the river system by giving only rainfall, sediment characteristics and topographic conditions, 2) to effectively control debris flow using the open type sabo dams, and 3) to flush sediment from a comparatively large reservoir.
Concerning with the theme 1), a numerical simulation method that combines the kinematic wave flood runoff analysis with the sediment entraining and detraining analysis is developed. A special contrivance to take the sediment supply from bare slopes is included. This method is applied to explain the sediment runoff within the watershed of Takase reservoir and the sediment disasters triggered by a severe rainfall in Venezuela, and it is proved valid and useful to examine the efficiencies of various countermeasures.
As for the theme 2), a stochastic model for the clogging of grid-type dam by boulders contained in debris flow is introduced. This model is combined with a particle segregation process model to numerically simulate the debris flow control by grid-type sabo dam. This method is proved valid by experiments.
Concerning with the theme 3), a new system to flush sediment from reservoir is invented. A small dam is constructed inside of the reservoir near the upstream end, and the yielded sediment accumulates only upstream of this sub-dam. During flood recession period, water and sediment stored upstream of the sub-dam are emptied through a bypass tunnel to the rfirer reach downstream of the main dam. If erosion of the delta deposit accumulated the backside of sub-dam is not sufficient, reverse flow from the main reservoir is introduced to scour the deposit. The feasibility of this system is examined by both laboratory experiments and numerical simulations, and it isproved feasible.
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