Imaichi Dam

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Imaichi Dam
Imaichi Dam left view.jpg
Imaichi Dam is located in Japan
Imaichi Dam
Location of Imaichi Dam in Japan
Country Japan
Location Nikkō, Tochigi Prefecture
Coordinates 36°49′31″N 139°39′58″E / 36.82528°N 139.66611°E / 36.82528; 139.66611Coordinates: 36°49′31″N 139°39′58″E / 36.82528°N 139.66611°E / 36.82528; 139.66611
Status Operational
Construction began 1979
Opening date 1986
Owner(s) TEPCO
Dam and spillways
Type of dam Gravity, concrete
Impounds Togawa River
Height 75.5 m (248 ft)
Length 177 m (581 ft)
Elevation at crest 551 m (1,808 ft)
Dam volume 192,000 m3 (251,127 cu yd)
Spillway capacity 1,620 m3/s (57,210 cu ft/s)
Total capacity 9,100,000 m3 (7,377 acre·ft)
Active capacity 6,200,000 m3 (5,026 acre·ft)
Catchment area 14.8 km2 (6 sq mi)
Surface area 380 m2 (0 acres)
Normal elevation 548.5 m (1,800 ft)
Power station
Commission date 1988
Hydraulic head 524 m (1,719 ft)
Turbines 3 x 350 MW (470,000 hp) Francis pump turbines
Installed capacity 1,050 MW (1,410,000 hp)

The Imaichi Dam (今市ダム) is a concrete gravity dam on the Togawa River located 4 kilometres (2.5 mi) west of Nikkō in Tochigi Prefecture, Japan. The dam serves as the lower reservoir for the 1,050 megawatts (1,410,000 hp) Imaichi Pumped Storage Power Station, while the Kuriyama Dam forms the upper. It is owned by TEPCO and was constructed between 1979 and 1986, with the first generator commissioned in 1988. Its reservoir can store 9,100,000 cubic metres (7,400 acre·ft) of water. Of that storage volume, 6,200,000 cubic metres (5,000 acre·ft) can be used for power generation.

Imaichi Pumped Storage Power Station[edit]

The power plant operates using the pumped storage hydroelectric method. During periods of high electricity demand, water is sent from the upper Kuriyama Reservoir to the power plant which contains 3 x 350 megawatts (470,000 hp) Francis pump turbines. Water discharged from the power plant then enters the Imaichi Reservoir. When demand is low, the pump-generators reverse mode and pump water from the lower reservoir back up to the upper. The process repeats as needed.[1][2]

See also[edit]


  1. ^ "Tokyo Electric Power Station Imaichi" (in Japanese). Retrieved 19 January 2012. 
  2. ^ Engineers, prepared by Task Committee on Pumped Storage of the Committee on Hydropower of the Energy Division of the American Society of Civil (1996). Hydroelectric pumped storage technology : international experience. New York, NY: American Soc. of Civil Engineers. pp. 2.2 1–5. ISBN 0-7844-0144-6.