Ikawa Dam
Encyclopedia
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 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...

 in Aoi-ku
Aoi-ku, Shizuoka
is one of three wards of Shizuoka, Shizuoka, Japan, located in the northern part of the city. Aoi-ku borders Suruga-ku in the south and Shimizu-ku to the southeast; the west faces Shimada, Fujieda and Kawanehon and its northern tip extends into the border between Nagano Prefecture and Yamanashi...

, Shizuoka
Shizuoka, Shizuoka
is the capital city of Shizuoka Prefecture, Japan, and the prefecture's second-largest city in terms of both population and area. It became one of Japan's 19 "designated cities" in 2005.-Geography:...

, Shizuoka Prefecture
Shizuoka Prefecture
is a prefecture of Japan located in the Chūbu region on Honshu island. The capital is the city of Shizuoka.- History :Shizuoka prefecture was formed from the former Tōtōmi, Suruga and Izu provinces.The area was the home of the first Tokugawa Shogun...

 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
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

. It was the first hollow core concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 gravity dam to be constructed in Japan, and has a hydroelectric power generating station owned by the Chubu Electric Power Company
Chubu Electric Power Company
, abbreviated as Chuden in Japanese, is the electric provider for the middle Chūbu region of the Honshū island of Japan. It provides electricity at 60 Hz, though an area of Nagano Prefecture uses 50 Hz. Chubu Electric Power ranks third among Japan’s largest electric utilities in terms of power...

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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.

In 1906, a joint venture
Joint venture
A joint venture is a business agreement in which parties agree to develop, for a finite time, a new entity and new assets by contributing equity. They exercise control over the enterprise and consequently share revenues, expenses and assets...

 company, the was established, and began studies and design work on plans to exploit the potential of the Ōi River and Fuji River
Fuji River
The is a river in Yamanashi and Shizuoka Prefectures of central Japan. It is long and has a watershed of . With the Mogami River and the Kuma River, it is regarded as one of the three most rapid flows of Japan....

 in Shizuoka Prefecture. The British interests were bought out by 1921, and electrical production nationalized under the aegis of the in 1938. The first dams on the Ōi River were completed in the late 1920s and early 1930s, but further work was suspended by the Great Depression
Great Depression
The Great Depression was a severe worldwide economic depression in the decade preceding World War II. The timing of the Great Depression varied across nations, but in most countries it started in about 1929 and lasted until the late 1930s or early 1940s...

 of the 1930s, and World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 in the 1940s. However, by the early 1950s, Japan’s need for electrical energy was growing exponentially, especially in the industrial belt near Nagoya. After the breakup of Nippon Hassoden at the end of World War II into various regional power utilities, the bulk of the dams on the Ōi River came under the control of Chubu Electric Power.

Design

Design work on the Ikawa Dam began in 1951, with construction starting in 1952 with a foreign aid grant from OCI, facilitated by the American occupation authorities
Supreme Commander of the Allied Powers
Supreme Commander of the Allied Powers was the title held by General Douglas MacArthur during the Occupation of Japan following World War II...

. The dam design introduced the technic of hollow-core concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 construction to Japan, which had previously been used with success in Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

. There was initial resistance to the technique by Japanese civil engineers, who were concerned with the earthquake resistance of the design, but the number of successful applications in earthquake-prone areas of northern Italy together with the economics of using less concrete swayed the decision towards the new technology. Construction of the 103.6 metres (339.9 ft) tall dam was facilitated by its location on the Ōigawa Railway Ikawa Line, and was completed in 1957. The associated Ikawa Hydroelectric Power Plant produces 62,000 KW of power.

As a result of the lake created by the Ikawa Dam, the village of Ikawa
Ikawa, Shizuoka
was a village located in Abe District, Shizuoka Prefecture, Japan.On January 1, 1969 Ikawa joined with neighboring Shizuoka city. It is now part of Aoi-ku, Shizuoka....

 was submerged, and its 550 households had to be relocated.

serves as an important source of tap water
Tap water
Tap water is a principal component of "indoor plumbing", which became available in urban areas of the developed world during the last quarter of the 19th century, and common during the mid-20th century...

, industrial water and irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

 water in Shizuoka Prefecture. The lake is stocked with cherry salmon, 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 trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

, and is a popular fishing spot. A museum established by Chubu Electric Power near the lake has exhibits relating to the history and construction of the dam, and on hydroelectric power in general.

Surroundings

Public access to the dam and its lake are by Shizuoka Prefectural Road 60, with bus connections to Shizuoka Station
Shizuoka Station
is a major railway station on the Tōkaidō Main Line of Central Japan Railway Company in Shizuoka, Japan, on the Tōkaidō Shinkansen and Tōkaidō Main Line. The station is 180.2 rail kilometers from Tokyo.-History:...

 or Shin-Shizuoka Station
Shin-Shizuoka Station
is a terminal train station of the Shizuoka-Shimizu Line in Aoi-ku, Shizuoka, Shizuoka Prefecture, Japan. It is located within the Shin-Shizuoka Cenova shopping complex.-History:...

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