The is a multi-purpose dam on the main stream

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 ...

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 ...

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. Kana ...

on the island of

Honshū , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island ...

, Japan.

History

The potential of the Sagami River valley 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 a ...

development began to be developed in the 1930s, with the growth of population in the Shonan region, and the expansion 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 ...

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. Plans for a dam on the Sagami River were submitted to the

Home Ministry An interior ministry (sometimes called a ministry of internal affairs or ministry of home affairs) is a government department that is responsible for internal affairs. Lists of current ministries of internal affairs Named "ministry" * Ministr ...

in 1935, but approval was delayed in favor of other projects. Instead, the Kanagawa Prefectural Assembly passed the necessary regulations and secured a special budget to begin work in 1938. After actual construction work did not begin immediately, due to the strong opposition of the 196 families who needed to be relocated from the area to be flooded by the dam. However, the wartime demands for power and industrial water by the

Yokosuka Naval Arsenal was one of four principal naval shipyards owned and operated by the Imperial Japanese Navy, and was located at Yokosuka, Kanagawa prefecture on Tokyo Bay, south of Yokohama. History In 1866, the Tokugawa shogunate government established th ...

and by the Keihin Industrial complex became critical, and General

Sadao Araki Baron was a general in the Imperial Japanese Army before and during World War II. As one of the principal nationalist right-wing political theorists in the Empire of Japan, he was regarded as the leader of the radical faction within the poli ...

ordered troops into the area to force compliance with the relocation. Work on the Sagami Dam began in 1941 by the

Kumagai Gumi is a Japanese construction company founded in Fukui, Fukui Prefecture, Japan. The company still has registered headquarters in Fukui, but the actual head office is located in Shinjuku, Tokyo. History Santaro Kumagai, the company's founder, be ...

construction company; however, 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 World War II by country, vast majority of the world's countries—including all of the great power ...

delayed completion until 1947.

Design

The Sagami Dam a hollow-core

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most ...

gravity dam. It was designed to provide

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 ...

, and industrial and drinking water to the cities of Yokohama, Kawasaki,

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 ...

and the

Shōnan is the name of a region along the coast of Sagami Bay in Kanagawa Prefecture, central Japan. Centered on Sagami River, about 60 kilometers southwest of Tokyo, the Shōnan region stretches from Ninomiya in the west to Fujisawa in the east, ...

area. The associated Sagami Hydroelectric Power Plant has a rated capacity of 31,000 KW of power . The reservoir created by the dam, Lake Sagami is also a major recreational location for Kanagawa Prefecture.

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

photo page
{{Dams in Kanagawa Prefecture Gravity dams Dams in Kanagawa Prefecture Hydroelectric power stations in Japan Dams completed in 1947

History

Design

See also

References

External links