The is a dam located between the cities of
Ena and
Nakatsugawa in
Gifu Prefecture
is a Prefectures of Japan, prefecture of Japan located in the Chūbu region of Honshu. Gifu Prefecture has a population of 1,910,511 () and has a geographic area of . Gifu Prefecture borders Toyama Prefecture to the north; Ishikawa Prefecture ...
, Japan. It was built to produce electricity for the surrounding area. The
Agi River
The is a river in Japan which flows through Gifu Prefecture. It is part of the Kiso River system.
Geography
The river originates from Mount Yaki on the border of Nakatsugawa, Gifu, Nakatsugawa and Ena, Gifu, Ena and flows west. It flows through ...
flows through the dam.
Built in 1924, the ÅŒi Dam was the first dam built anywhere on the
Kiso River system. It is also the first full-scale
hydroelectric dam
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...
built in Japan.
At tall,
it is the largest
gravity dam
A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using only the weight of the material and its resistance against the foundation. Gravity dams are designed so that each section of the dam is ...
in Japan after the
Taishakugawa Dam in
Hiroshima Prefecture. In 1983, the New Ōi Dam (新大井ダム''Shin-Ōi Damu'') was built just downstream. Combined, they produce 80,000 kW of power.
History
The upper portions of the Kiso River have a strong flow in terms of speed and volume, making it an ideal location for hydroelectric dams. Interest in hydroelectric dams in Japan grew greatly in 1911 when a hydroelectric law was passed. Given the technologies of the time, though, building a dam along the Kiso River was too difficult because floods often occurred.
The introduction of hydroelectric power at ÅŒi Dam is considered the greatest lifetime achievement of businessman
Momosuke Fukuzawa.
Surrounding area
The
reservoir
A reservoir (; ) is an enlarged lake behind a dam, usually built to water storage, store fresh water, often doubling for hydroelectric power generation.
Reservoirs are created by controlling a watercourse that drains an existing body of wa ...
created by the dam was named
Ena Gorge. More than , the gorge is lined by rocky walls on both sides. Along with the lake created by the
Maruyama Dam downstream, the area has been designated the
Hida-Kisogawa Quasi-National Park.
References
External links
{{DEFAULTSORT:Oi Dam
Dams in Gifu Prefecture
Dams completed in 1924