The is a

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

on the

Nakatsu River The is a river in Iwate Prefecture, Japan. It flows through the city of Morioka, where it enters the Kitakami River The is the fourth largest river in Japan and the largest in the Tōhoku region. It is long and drains an area of . page 7 ...

, a main

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drai ...

of the

Sagami River The is a river in Kanagawa and Yamanashi Prefectures on the island of Honshū, Japan. The upper reaches of the river in Yamanashi prefecture are also sometimes known as the , and the portion near the river mouth as the . The river overall was ...

in Aikō District,

Kanagawa Prefecture is a prefecture of Japan located in the Kantō region of Honshu. Kanagawa Prefecture is the second-most populous prefecture of Japan at 9,221,129 (1 April 2022) and third-densest at . Its geographic area of makes it fifth-smallest. Kanag ...

, Japan. It straddles the border between the village of Kiyokawa, town of Aikawa and the former town of Tsukui (now part of the city of

Sagamihara is a city in Kanagawa Prefecture, Japan. , the city has an estimated population of 723,470, with 334,812 households, and a population density of 1,220 persons per km2. The total area of the city is . Sagamihara is the third-most-populous city ...

History

The potential of the Sagami River for

hydroelectric power 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 ...

development began to be developed in the 1930s, with the growth of industry and electrical consumption in the

Yokohama is the second-largest city in Japan by population and the most populous municipality of Japan. It is the capital city and the most populous city in Kanagawa Prefecture, with a 2020 population of 3.8 million. It lies on Tokyo Bay, south of T ...

Kanagawa is a prefecture of Japan located in the Kantō region of Honshu. Kanagawa Prefecture is the second-most populous prefecture of Japan at 9,221,129 (1 April 2022) and third-densest at . Its geographic area of makes it fifth-smallest. Kanagaw ...

industrial belt. Work on the Sagami Dam, the first dam on the main stream of the Sagami River began in 1938; however, lack of funding and the advent of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

delayed completion until after the end of the war. Work on the Shiroyama Dam was completed in 1965. The growth in population of nearby Atsugi and increased need for industrial and drinking water spurred plans for additional dams on the Sagami River's tributaries. Plans for the Miyagase Dam were finalized in 1969 with work commencing in 1971. Due to the huge size of the dam, and the need relocate some 300 households from the area flooded by the dam, construction was not completed until the year 2000.

Design

The Miyagase Dam is a hollow-core concrete gravity dam. It was designed and built by a consortium of the Kajima Construction, Obayashi Corp. and the Toda Corporation. The dam was designed as a multi-purpose dam. In addition to providing

flood control Flood control methods are used to reduce or prevent the detrimental effects of flood waters."Flood Control", MSN Encarta, 2008 (see below: Further reading). Flood relief methods are used to reduce the effects of flood waters or high water level ...

, it provides 90% of the tap water to two-thirds of the population of Kanagawa Prefecture, including the cities of Kawasaki,

and

Yokosuka is a city in Kanagawa Prefecture, Japan. , the city has a population of 409,478, and a population density of . The total area is . Yokosuka is the 11th most populous city in the Greater Tokyo Area, and the 12th in the Kantō region. The city ...

. It also provides water to the associated Aikawa Hydroelectric Power Plant, which has a rated capacity of 24,000 KW of power. The tall dam is the second tallest in the Kantō region. Miyagase Dam is the highest and the largest roller-compacted concrete dam in Japan. The reservoir created by the dam, is a popular recreation spot in Kanagawa Prefecture.

Surroundings

Public access to the dam and its lake is provided by National Route 412.

References

* Japan Commission on Large Dams. ''Dams in Japan:Past, Present and Future''. CRC Press (2009). * Takeuchi, Kuniyoshi. ''Sustainable Reservoir Development and Management''. IAHS Press (November 1998).

External links

National government website

Local website)
{{Dams in Kanagawa Prefecture Gravity dams Dams in Kanagawa Prefecture Hydroelectric power stations in Japan Dams completed in 2000 Aikawa, Kanagawa Sagamihara Kiyokawa, Kanagawa 2000 establishments in Japan