The is a dam located between the cities of

Ena Ena or ENA may refer to: Education * École nationale d'administration, French Grande école, for civil service * Education Networks of America, Internet service provider Fictional characters * Ena Sharples, from the British soap opera ''Coron ...

and

Nakatsugawa Magome-juku on the Nakasendō is a city located in Gifu, Japan. , the city had an estimated population of 78,930, and a population density of 120 persons per km2 in 30,788 households The total area of the city was . Geography Nakatsugawa is in ...

in Gifu Prefecture, Japan. It was built to produce electricity for the surrounding area. The Agi River flows through the dam. Built in 1924, the Ōi Dam was the first dam built anywhere on the Kiso River system. It is also the first

hydroelectric dam Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

built in Japan. At tall, it is the largest gravity dam 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.

Surrounding area

The

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

created by the dam was named

Ena Gorge is a river valley located at the mid reaches of the Kiso River, which runs through the cities of Ena and Nakatsugawa in Gifu Prefecture, Japan. Ena Gorge was so named by Shiga Shigetaka, a geographer of that time who praised the harmony of th ...

. More than , the gorge is lined by rocky walls on both sides. Along with the lake created by the

Maruyama Dam The is a dam on the border of Mitake and Yaotsu in Gifu Prefecture, Japan. It was built on the upper reaches of the Kiso River system. It is a gravity dam that is tall. It was built after World War II World War II or the S ...

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