バイパス設置による貯水池土砂管理効果の定量的把握

抄録

Reservoir sedimentation causes various problems, such as storage capacity losses and the risk of blocking intake structures. It will be necessary to manage those sediments properly in order to obtain sustainable long-term use of existing reservoirs. On specific condition, bypass tunnels is effective to prevent reservoir sedimentation. Bypass tunnels have inlet at upstream of dam, and outlet downstream of dam. During floods, discharge sediment from upstream will pass thorough bypass tunnels and those schemes can prevent reservoir sedimentation.

In this paper, we study quantitative evaluation of a bypass tunnel to prevent reservoir sedimentation as a case study on Nunobiki reservoir in Kobe. The results show that sedimentation rates have drastically decreased to about 1/20 with a bypass tunnel, and the bypass tunnel was effective for sedimentation management in case of Nunobiki reservoir over a long time.