Senzu Dam
Encyclopedia
The is a dam
on the Sumata River, a tributary of the Ōi River
, located in Kawanehon Town
, Haibara District
, Shizuoka Prefecture
on the island of Honshū
, Japan
.
company, the was established, and began studies and design work on plans to exploit the potential of the Ōi River and Fuji River
in Shizuoka Prefecture. The British interests were bought out by 1921, and the company was renamed . As early as the late 1920s, developers began to turn their attention to various tributary streams
of the Ōi River, especially the Sumata River, with its steep-sided gorge and considerable flow volume.
Construction work began on the Senzu Dam in 1930 and was completed by 1935 by the Hazama Corporation. The water is channeled eight kilometers away to the with a rated capacity of 22,200 KW. Construction was facilitated by the Ōigawa Railway
, which had been completed by 1927.
Electrical production was nationalized under the aegis of the in 1938, which was divided after World War II
into regional power corporations. Senzu Dam is now operated and maintained by the Chubu Electric Power Company
.
s. When completed, it was the highest concrete gravity dam in central Japan, and won a design award from the Japan Civil Engineering Association. However, the designers did not take into account the high levels of silt
and sedimentation in the Sumata River. By 2002, it was estimated that over 97.7% of the usable capacity of Senzu Dam was filled with mud, and must now be constantly dredged to permit flow of water for power generation.
and can be reached from Senzu Station
on the Ōigawa Railway. The area is popular with mountain climbers heading towards the high peaks of the Minami Alps National Park
.
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 Sumata River, 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 Kawanehon Town
Kawanehon, Shizuoka
is a town located in Haibara District, Shizuoka, Japan. As of February 2010, the town has an estimated population of 8,253 and a density of 16.8persons per km². The total area was 496.72 km².-Geography:...
, Haibara District
Haibara District, Shizuoka
Haibara is a district located in Shizuoka, Japan.As of 2004, the district has an estimated population of 95,091 and a density of 126.88 persons per km²...
, 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...
.
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 ventureJoint 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 the company was renamed . As early as the late 1920s, developers began to turn their attention to various tributary streams
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...
of the Ōi River, especially the Sumata River, with its steep-sided gorge and considerable flow volume.
Construction work began on the Senzu Dam in 1930 and was completed by 1935 by the Hazama Corporation. The water is channeled eight kilometers away to the with a rated capacity of 22,200 KW. Construction was facilitated by the Ōigawa Railway
Oigawa Railway
The is a railway company in Shizuoka Prefecture, Japan. The company is commonly known as . The company belongs to Meitetsu Group. The first section of its lines opened in 1927....
, which had been completed by 1927.
Electrical production was nationalized under the aegis of the in 1938, which was divided after 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...
into regional power corporations. Senzu Dam is now operated and maintained 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...
.
Design
The Senzu Dam is a solid core concrete gravity dam with dual spillwaySpillway
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...
s. When completed, it was the highest concrete gravity dam in central Japan, and won a design award from the Japan Civil Engineering Association. However, the designers did not take into account the high levels of silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
and sedimentation in the Sumata River. By 2002, it was estimated that over 97.7% of the usable capacity of Senzu Dam was filled with mud, and must now be constantly dredged to permit flow of water for power generation.
Surroundings
Senzu Dam is located near Sumata OnsenOnsen
An is a term for hot springs in the Japanese language, though the term is often used to describe the bathing facilities and inns around the hot springs. As a volcanically active country, Japan has thousands of onsen scattered along its length and breadth...
and can be reached from Senzu Station
Senzu Station
is a railway station Kawanehon, Haibara District, Shizuoka Prefecture, Japan. It is the terminal station for the Ōigawa Main Line and the Ikawa Line, and is operated by the Ōigawa Railway.- Station history:...
on the Ōigawa Railway. The area is popular with mountain climbers heading towards the high peaks of the Minami Alps National Park
Minami Alps National Park
is a national park in the Chūbu region, Honshū, Japan.The Minami Alps National Park was established on June 1, 1964. It extends along the border of Shizuoka, Yamanashi and Nagano Prefectures for a length of , and a maximum width of for a total area of...
.