The is a dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 on the Tonaka River, a tributary stream of the Misakubo River, itself a tributary of the Ōi River

Oi River

The is a river in Shizuoka Prefecture, Japan.-Geography:The Ōi River flows from the Akaishi Mountains, the branch of the Japanese Southern Alps which form the border between Shizuoka, Nagano and Yamanashi prefectures. These mountains, with peaks ranging from 2000–3000 meters, are characterized by...

, located in Tenyrū-ku

Tenryū-ku, Hamamatsu

is one of the seven wards of the city of Hamamatsu, Shizuoka Prefecture, Japan. It is bordered by Kita-ku and Hamakita-ku in Hamamatsu, the cities of Shimada and Iwata and towns of Mori and Kawanehon in Shizuoka, Shishiro, Tōei and Toyone in Aichi Prefecture and Iida and Tenryū in Nagano...

 Hamamatsu, Shizuoka

Hamamatsu, Shizuoka

is a city located in western Shizuoka Prefecture, Japan. On July 1, 2005, the city merged with 11 surrounding cities and towns. It became a city designated by government ordinance on April 1, 2007.- History :...

 Prefecture, on the island of Honshū

Honshu

is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...

, Japan.

History

The potential of the Ōi River valley for hydroelectric power development was realized by the Meiji government at the start of the 20th century. The Ōi River was characterized by a high volume of flow and a fast current. Its mountainous upper reaches and tributaries were areas of steep valleys and abundant rainfall, and were sparsely populated. From the 1930s through the 1960s, numerous concrete gravity dams had been constructed on the main flow of the Ōi River, and on its various tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 streams. The remote and steep-walled Misakubo valley was uninhabited, and was designated as the site for a new dam in the early 1960s.

Construction

The Misakubo Dam was constructed to provide water for the 50,000 KW Misakubo Hydroelectric Plant. Construction work began in 1967 and was completed by 1969 by the Hazama Corporation at a cost of 11 billion yen. Unlike other dams on the Ōi River, the Misakubo is a rock-fill dam. Water from the dam is also diverted to the Sakuma Dam

Sakuma Dam

The is a dam on the Tenryū River, located on the border of Toyone, Kitashitara District, Aichi Prefecture on the island of Honshū, Japan. It is one of the tallest dams in Japan and supports a 350 MW hydroelectric power station...

, where it provides increased flow to the hydroelectric power plant there.
The Misakubo Reservoir created by the dam has been stocked with carp

Carp

Carp are various species of oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. The cypriniformes are traditionally grouped with the Characiformes, Siluriformes and Gymnotiformes to create the superorder Ostariophysi, since these groups have certain...

 and Japanese smelt and is a popular fishing location due to its ease of access via Japan National Route 152.