Otori Dam

The Otori Dam (大鳥ダム, Ōtori damu) is a concrete arch-gravity dam on the Tadami River, 17 km (11 mi) southwest of Tadami in Fukushima Prefecture, Japan. The primary purpose of the dam is hydroelectric power generation and it supports a 182 MW power station. The power station contains two Kaplan turbine-generators. Unit 1 (95 MW) was commissioned on 20 November 1963 while Unit 2 (87 MW) was commissioned on 7 June 2003 as part of a power plant expansion project that included an additional 200 MW generator at Okutadami Dam upstream. The dam is 83 m (272 ft) tall and 188 m (617 ft) long. Its reservoir has a 15,800,000 m3 (12,809 acre⋅ft) capacity of which 5,000,000 m3 (4,054 acre⋅ft) is active (or "useful") for power generation. The reservoir has a catchment area of 656.9 km2 (254 sq mi) and surface area of 89 ha (220 acres). Of the two generators, Unit 1 has a maximum effective hydraulic head of 50.8 m (167 ft) and Unit 2 is afforded 48.1 m (158 ft). The design flood discharge of the dam is 2,200 m3/s (77,692 cu ft/s) and its service spillway is controlled by three tainter gates