Shin-Takasegawa Pumped Storage Station

Creating the upper reservoir is the Takase Dam which is a 176-metre (577 ft) tall and 362-metre (1,188 ft) long rock-fill embankment dam with a structural volume of 11,586,000 cubic metres (15,154,000 cu yd). The Takase Reservoir has a 76,200,000 cubic metres (61,800 acre⋅ft) capacity of which only 16,200,000 cubic metres (13,100 acre⋅ft) is active (or "useful") for power generation. The low active capacity of the reservoir is due to the high levels of silt in the Takase River which cause the reservoir to reserve 79 percent of its capacity for this purpose. During operation, the upper reservoir only draws down 10 metres (33 ft).[1]

During periods of high energy demand, water from the Takase Reservoir is released down to the power station. After received by the intake, water initially travels along two 8 metres (26 ft) diameter and 2,600 metres (8,500 ft) long head-race tunnels. At the terminus of these tunnels, they split into four 330 metres (1,080 ft) long penstocks which drop down a 200 metres (660 ft) deep shaft to the underground power station. At the power station, the water operates four 320 megawatts (430,000 hp) reversible Francis turbine-generators before being discharged into the lower reservoir, created by the Nanakura Dam.

The Nanakura Dam is a 125-metre (410 ft) tall and 340-metre (1,120 ft) long rock-fill embankment dam with a structural volume of 7,380,000 cubic metres (9,650,000 cu yd). The reservoir created by the dam, the lower reservoir, has a 32,500,000 cubic metres (26,300 acre⋅ft) capacity of which 16,200,000 cubic metres (13,100 acre⋅ft) is active. To protect in against rapid draw-down in water levels (as much as 28 metres (92 ft)), the top of the dam is coated in hard rock materials.[1]