Takase Dam was added to Your Favorites!
Chubu-Sangaku NP, Nagano
Claim this place to tell your story your way.
Takase Dam rises 176 m, making it Japan’s tallest rock-fill dam and second-tallest dam overall. Its vast embankment contains about 11.59 million m³ of material.
Takase and nearby Nanakura dams work like a giant battery: water is pumped uphill to Takase when electricity demand is low, then sent downhill to generate power when demand rises. The plant can produce up to 1.28 million kW.
Takase’s flood spillway uses a ski-jump design: instead of simply dropping water beside the dam, it launches the flow outward to dissipate its force. Its design flood discharge is 1,400 m³ per second.
The dam’s rising reservoir would have submerged the older Takase River Fifth Power Station. Engineers relocated it and raised it by about 24 m—so a pre-dam power plant could keep operating.
The power station connected to Takase Dam was built underground. Its location inside Chubu-Sangaku National Park—and the heavy snow—were reasons to tuck the facility out of sight and weather.
Takase receives an average of about 730,000 m³ of sediment a year; roughly 55% comes from the nearby Nigorisawa and Fudosawa streams. Government plans propose an 11 km tunnel with a conveyor to move sediment downstream.
During the July 2006 heavy rain, Takase and Nanakura coordinated a special operation with downstream Omachi Dam. The collaboration helped reduce rising water levels in the Sai River basin and lessen flood damage.
The story of the engineers who worked to build Takase and Nanakura dams reached beyond the construction site: Ayako Sono made their efforts the subject of her 1985 novel, 湖水誕生 (Kosu Tanjō).
