Miho Dam
Encyclopedia
The is a multi-purpose dam
on the Kawauchi River, a tributary stream of the Sakawa River in the town of Yamakita
, Ashigarakami District
, Kanagawa Prefecture
on the island of Honshū
, Japan
. The dam is located within the borders of the Tanzawa-Ōyama Quasi-National Park
.
project to promote the local economies of towns in western Kanagawa prefecture. Justification was provided by the projected growth in population of Odawara
with the completion of the Tōkaidō Main Line
railway and Tōmei Expressway
and the continuing growth in demand from the Kawasaki
-Yokohama
industrial area for drinking and industrial water.
Work on the Miho Dam began in 1969 by the Kumagai Gumi
construction company; and was completed in 1978. Construction involved the relocation of 233 households from the area scheduled to be flooded by the dam. Part of the relocation agreement included a promise to retain historic local place names, which resulted in the name of the dam being changed from the planned “Sakawa Dam” to “Miho Dam” in reflection of the local district name.
, with an initial design height of 100 meters, which was later lowered to 95 meters. Unusual for a rock-fill dam, the center portion of the dam is made of concrete
and incorporates five spillway
s. The associated Tanoiri Hydroelectric Power Plant has a rated capacity of 7,400 KW of power. The reservoir created by the dam, Lake Tanzawa
is also a major recreational location for Kanagawa Prefecture.
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 Kawauchi River, a tributary stream of the Sakawa River in the town of Yamakita
Yamakita, Kanagawa
is a town located in Ashigarakami District, Kanagawa Prefecture, Japan. As of 2010, the town had an estimated population of 11,863 and a density of 52.8 persons per km². The total area was 224.70 km².-Geography:...
, Ashigarakami District
Ashigarakami District, Kanagawa
is an administrative district of Japan located in western Kanagawa Prefecture. Most of the mountainous district is sparsely populated, and is part of the Tanzawa-Ōyama Quasi-National Park.-History:...
, Kanagawa Prefecture
Kanagawa Prefecture
is a prefecture located in the southern Kantō region of Japan. The capital is Yokohama. Kanagawa is part of the Greater Tokyo Area.-History:The prefecture has some archaeological sites going back to the Jōmon period...
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...
. The dam is located within the borders of the Tanzawa-Ōyama Quasi-National Park
Tanzawa-Ōyama Quasi-National Park
is a quasi-national park in the Kantō region of Honshū in Japan. It is rated a protected landscape according to the IUCN. The park includes the Tanzawa Mountains, Miyagase Dam and its surrounding forests, Hayato Great Falls and the religious sites of Mount Ōyama in the mountains of western...
.
History
Development of the Sakawa River began in the 1960s, as a public worksPublic works
Public works are a broad category of projects, financed and constructed by the government, for recreational, employment, and health and safety uses in the greater community...
project to promote the local economies of towns in western Kanagawa prefecture. Justification was provided by the projected growth in population of Odawara
Odawara, Kanagawa
is a city located in western Kanagawa Prefecture, Japan. As of 2010, the city had an estimated population of 198,466 with a population density of 1,740 persons per km² . The total area was .-Geography:...
with the completion of the Tōkaidō Main Line
Tokaido Main Line
The is the busiest trunk line of the Japan Railways Group , connecting Tōkyō and Kōbe stations. It is long, not counting its many freight feeder lines around the major cities...
railway and Tōmei Expressway
Tomei Expressway
The is a national expressway on the island of Honshū in Japan. It is operated by Central Nippon Expressway Company. It is a part of Asian Highway Network -Naming:The word Tōmei is an acronym consisting of two kanji characters...
and the continuing growth in demand from the Kawasaki
Kawasaki, Kanagawa
is a city located in Kanagawa Prefecture, Japan, between Tokyo and Yokohama. It is the 9th most populated city in Japan and one of the main cities forming the Greater Tokyo Area and Keihin Industrial Area....
-Yokohama
Yokohama
is the capital city of Kanagawa Prefecture and the second largest city in Japan by population after Tokyo and most populous municipality of Japan. It lies on Tokyo Bay, south of Tokyo, in the Kantō region of the main island of Honshu...
industrial area for drinking and industrial water.
Work on the Miho Dam began in 1969 by the Kumagai Gumi
Kumagai Gumi
is a 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.Kumagai Gumi was removed from the Nikkei 225 index on Oct...
construction company; and was completed in 1978. Construction involved the relocation of 233 households from the area scheduled to be flooded by the dam. Part of the relocation agreement included a promise to retain historic local place names, which resulted in the name of the dam being changed from the planned “Sakawa Dam” to “Miho Dam” in reflection of the local district name.
Design
The Miho Dam a rock-fill damEmbankment dam
An embankment dam is a massive artificial water barrier. It is typically created by the emplacement and compaction of a complex semi-plastic mound of various compositions of soil, sand, clay and/or rock. It has a semi-permanent waterproof natural covering for its surface, and a dense, waterproof...
, with an initial design height of 100 meters, which was later lowered to 95 meters. Unusual for a rock-fill dam, the center portion of the dam is made of 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...
and incorporates five spillway
Spillway
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. The associated Tanoiri Hydroelectric Power Plant has a rated capacity of 7,400 KW of power. The reservoir created by the dam, Lake Tanzawa
Lake Tanzawa
, is a lake located to the east of Mt. Fuji in Yamakita town, Ashigarakami district, in the Kanagawa Prefecture of Japan. It was created due to construction of the Miho dam in 1978. The lake and its surroundings are frequently visited during fall to admire autumn colors....
is also a major recreational location for Kanagawa Prefecture.