The Japanese title says: “July 2, 2021 Miwa Dam sediment bypass tunnel release begins.” ”I went to see the discharge from Miwa Dam and Takatoh Dam, as it was broadcast from the Ina City Disaster Prevention and Administration Radio.” // Location: Miwa Dam, 345 Hasehiji, Ina City, Nagano, Japan.
It is a sediment bypass tunnel. The entire tunnel facility for taking in sediment and turbid water that flow into the reservoir during a flood from the upstream of the reservoir, bypassing the reservoir with a tunnel, and discharging it to the downstream of the dam. This makes it possible to prevent the accumulation of inflowing sediment into the reservoir and the generation of turbid water in the reservoir, and it is also possible to reproduce the proper movement of sediment that the river originally has.
