貯水池逆流システムによるフラツシング排砂

抄録

Reservoir sedimentation has strong influence not only on the function of reservoir but also on the balance of sediment through the river system. Although various methods for controlling reservoir sedimentation are available, the effectiveness and applicability are limited. Therefore, some new methods should be developed. We propose a new flushing system that is a combination of a by-pass tunnel and a sub-dam. The sub-dam is a small dam constructed at a little downstream of the upstream end of reservoir and equipped with a gate and an introductory channel. During a flood, the sub-dam is submerged beneath the reservoir water, and sediment is deposited upstream of the sub-dam forming a delta. After the flood, water stored upstream of the sub-dam is drained away through the by-pass tunnel. Then, the delta is eroded by the flow introduced from the gate of the sub-dam. The eroded sediment is transported into the by-pass tunnel. Efficiency of the introductory channel to control erosion process is investigated by flume tests. Two-dimensional numerical simulation is also carried out to reproduce the experimental results.