Tamahara Dam

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Tanbara Dam
Tambara Dam right view.jpg
Tamahara Dam is located in Japan
Tamahara Dam
Location of Tanbara Dam in Japan
Country Japan
Location Numata
Coordinates 36°46′29″N 139°03′46″E / 36.77472°N 139.06278°E / 36.77472; 139.06278Coordinates: 36°46′29″N 139°03′46″E / 36.77472°N 139.06278°E / 36.77472; 139.06278
Status Operational
Construction began 1973
Opening date 1981
Owner(s) TEPCO
Dam and spillways
Type of dam Embankment, rock-fill
Impounds Tone River tributary
Height 116 m (381 ft)
Length 570.1 m (1,870 ft)
Elevation at crest 1,177 m (3,862 ft)
Width (crest) 12 m (39 ft)
Width (base) 550 m (1,800 ft)
Dam volume 5,435,000 m3 (7,109,000 cu yd)
Total capacity 14,800,000 m3 (12,000 acre·ft)
Active capacity 13,000,000 m3 (11,000 acre·ft)
Catchment area 6.5 km2 (2.5 sq mi)
Surface area 57 ha (140 acres)
Normal elevation 1,173 m (3,848 ft)
Power Station
Commission date 1986
Hydraulic head 518 m (1,699 ft) (effective)
Turbines 4 x 300 MW (400,000 hp) Francis pump-turbines
Installed capacity 1,200 MW (1,600,000 hp)

Tanbara Dam (玉原ダム, which can be mistakenly read Tamahara Dam[1]) is a rock-fill embankment dam on a Tone River tributary in Gunma Prefecture of Japan. It is located 14 kilometres (8.7 mi) north of Numata. It creates the upper reservoir for the 1,200 megawatts (1,600,000 hp) Tamahara Pumped Storage Power Station (玉原発電所). Construction began in 1973 and the dam was complete in 1981 while the power station was commissioned in 1986. It is 116 metres (381 ft) tall and withholds a reservoir with a storage capacity of 14,800,000 m3 (11,999 acre·ft). Of that capacity, 13,000,000 cubic metres (11,000 acre·ft) is active (or useful) for power generation. The lower reservoir for the pumped-storage power station is created by the Fujiwara Dam, located 4 km (2 mi) to the northwest on another Tone River tributary. Power is generated during periods of high energy demand and pumping occurs during times when energy demand is low such as at night. The power station contains four 300 megawatts (400,000 hp) reversible Francis turbine pump-generators which serve to both pump water and generate electricity. The upper Tamahara Reservoir is at an elevation of 1,177 metres (3,862 ft) and the lower Fujiwara Reservoir is at 651 metres (2,136 ft) which affords the power station an effective hydraulic head of 518 metres (1,699 ft). When pumping, the pump-generators can move up to 210 cubic metres per second (7,400 cu ft/s) of water and when generating, they discharge up to 276 cubic metres per second (9,700 cu ft/s).[2][1]

See also[edit]


  1. ^ a b "Tokyo Electric Power Co. power plant Tamahara" (in Japanese). Suiryoku. Retrieved 17 February 2012. 
  2. ^ "Hydropower & Dams in South and East Asia" (PDF). Hydropower and Dams. p. 9. Retrieved 3 October 2010.