The is a river in central
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 separa ...
,
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. With a length of , it is Japan's ninth longest river.
Its source is
Lake Suwa
is a lake in the Kiso Mountains, in the central region of Nagano Prefecture, Japan.
Geography
The lake is the source of the Tenryū River. It ranks 24th in lake water surface area in Japan. The cities of Suwa and Okaya and the town of Shimosuw ...
in the
Kiso Mountains
are a mountain range in Nagano and Gifu prefectures in Japan. They are also called the and they combine with the Hida Mountains ("Northern Alps") and the Akaishi Mountains ("Southern Alps") to form a group collectively known as the Japanese ...
near
Okaya in
Nagano Prefecture
is a landlocked prefecture of Japan located in the Chūbu region of Honshū. Nagano Prefecture has a population of 2,052,493 () and has a geographic area of . Nagano Prefecture borders Niigata Prefecture to the north, Gunma Prefecture to the ...
. It then flows through
Aichi Prefecture
is a prefecture of Japan located in the Chūbu region of Honshū. Aichi Prefecture has a population of 7,552,873 () and a geographic area of with a population density of . Aichi Prefecture borders Mie Prefecture to the west, Gifu Prefectur ...
and western
Shizuoka Prefecture
is a prefecture of Japan located in the Chūbu region of Honshu. Shizuoka Prefecture has a population of 3,637,998 and has a geographic area of . Shizuoka Prefecture borders Kanagawa Prefecture to the east, Yamanashi Prefecture to the northea ...
.
Geography
The Tenryū River is the only river exiting Lake Suwa. It follows a generally southern course. The upper reaches of the river in the Ina Basin of Nagano Prefecture is a rich agricultural area. The river exits through a gap between the
Kiso Mountains
are a mountain range in Nagano and Gifu prefectures in Japan. They are also called the and they combine with the Hida Mountains ("Northern Alps") and the Akaishi Mountains ("Southern Alps") to form a group collectively known as the Japanese ...
(Central Alps) and the
Akaishi Mountains (Southern Alps), which forms the border between Shizuoka and Nagano Prefectures . This area is characterized by heavy rainfall (up to 3000 mm per year) and deep V-shaped valleys. Continuing south through Shizuoka Prefecture, the river drains a wide coastal plain noted for fruit and rice production. The city of
Hamamatsu
is a city located in western Shizuoka Prefecture, Japan. the city had an estimated population of 791,707 in 340,591 households, making it the prefecture's largest city, and a population density of . The total area of the site was .
Overview
...
is near the
river mouth
A river mouth is where a river flows into a larger body of water, such as another river, a lake/reservoir, a bay/gulf, a sea, or an ocean. At the river mouth, sediments are often deposited due to the slowing of the current reducing the carrying ...
at the
Philippine Sea
The Philippine Sea is a marginal sea of the Western Pacific Ocean east of the Philippine archipelago (hence the name), the largest in the world, occupying an estimated surface area of . The Philippine Sea Plate forms the floor of the sea. Its ...
.
History
The Tenryū River is mentioned in
Nara period
The of the history of Japan covers the years from CE 710 to 794. Empress Genmei established the capital of Heijō-kyō (present-day Nara). Except for a five-year period (740–745), when the capital was briefly moved again, it remained the cap ...
records as the for its fast, turbulent flow and its propensity to flood. The upper portion of the river (in
Shinano Province
or is an old province of Japan that is now Nagano Prefecture.
Shinano bordered on Echigo, Etchū, Hida, Kai, Kōzuke, Mikawa, Mino, Musashi, Suruga, and Tōtōmi Provinces. The ancient capital was located near modern-day Matsumoto, whi ...
) was referred to as the Tenryūgawa, whereas the lower portion (in
Tōtōmi Province
was a province of Japan in the area of Japan that is today western Shizuoka Prefecture. Nussbaum, Louis-Frédéric. (2005). "''Tōtōmi''" in . Tōtōmi bordered on Mikawa, Suruga and Shinano Provinces. Its abbreviated form name was . The or ...
) was often referred to as the . In various entries in the national historical chronicle ''
Shoku Nihongi
The is an imperially-commissioned Japanese history text. Completed in 797, it is the second of the ''Six National Histories'', coming directly after the '' Nihon Shoki'' and followed by ''Nihon Kōki''. Fujiwara no Tsugutada and Sugano no Mamichi ...
'', flooding of the river is mentioned in the years 710 CE and 765 CE. Records through the
Heian period
The is the last division of classical Japanese history, running from 794 to 1185. It followed the Nara period, beginning when the 50th emperor, Emperor Kanmu, moved the capital of Japan to Heian-kyō (modern Kyoto). means "peace" in Japanese. ...
and
Kamakura period
The is a period of Japanese history that marks the governance by the Kamakura shogunate, officially established in 1192 in Kamakura by the first ''shōgun'' Minamoto no Yoritomo after the conclusion of the Genpei War, which saw the struggle bet ...
are sparse, but from the
Muromachi period
The is a division of Japanese history running from approximately 1336 to 1573. The period marks the governance of the Muromachi or Ashikaga shogunate (''Muromachi bakufu'' or ''Ashikaga bakufu''), which was officially established in 1338 by t ...
, increasing efforts at
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 ...
were made by various warlords and landholders along the river by construction of dikes,
levee
A levee (), dike (American English), dyke (English in the Commonwealth of Nations, Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually soil, earthen and that often runs parallel (geometry), parallel to ...
s, and channels.
With the occupation of
Hamamatsu Castle
is a replica ''hirayama''-style Japanese castle. It was the seat of various ''fudai daimyō'' who ruled over Hamamatsu Domain, Tōtōmi Province, in what is now central Hamamatsu, Shizuoka Prefecture, Japan under the Edo period Tokugawa shog ...
by
Tokugawa Ieyasu
was the founder and first ''shōgun'' of the Tokugawa Shogunate of Japan, which ruled Japan from 1603 until the Meiji Restoration in 1868. He was one of the three "Great Unifiers" of Japan, along with his former lord Oda Nobunaga and fellow ...
, considerable efforts were made to increase the revenues of Tōtōmi Province through creation of new rice fields with irrigation from the Tenryū River. However, flooding remained a problem, including a great flood in 1674 which washed away many of the earthen works of previous centuries.
Transport
During the
Edo period
The or is the period between 1603 and 1867 in the history of Japan, when Japan was under the rule of the Tokugawa shogunate and the country's 300 regional '' daimyo''. Emerging from the chaos of the Sengoku period, the Edo period was characteriz ...
, the
Tōkaidō (road) developed as the major highway linking
Edo with
Kyoto
Kyoto (; Japanese: , ''Kyōto'' ), officially , is the capital city of Kyoto Prefecture in Japan. Located in the Kansai region on the island of Honshu, Kyoto forms a part of the Keihanshin metropolitan area along with Osaka and Kobe. , the ci ...
, and ''
daimyō
were powerful Japanese magnates, feudal lords who, from the 10th century to the early Meiji era, Meiji period in the middle 19th century, ruled most of Japan from their vast, hereditary land holdings. They were subordinate to the shogun and n ...
s'' from the western
domains were forced to travel on a regular basis to Edo to attend to the ''
shōgun
, officially , was the title of the military dictators of Japan during most of the period spanning from 1185 to 1868. Nominally appointed by the Emperor, shoguns were usually the de facto rulers of the country, though during part of the Kamakur ...
'' in a system known as ''
sankin-kōtai
''Sankin-kōtai'' ( ja, 参覲交代/参覲交替, now commonly written as ja, 参勤交代/参勤交替, lit=alternate attendance, label=none) was a policy of the Tokugawa shogunate during most of the Edo period of Japanese history.Jansen, M ...
''. However, the
Tokugawa shogunate
The Tokugawa shogunate (, Japanese 徳川幕府 ''Tokugawa bakufu''), also known as the , was the military government of Japan during the Edo period from 1603 to 1868. Nussbaum, Louis-Frédéric. (2005)"''Tokugawa-jidai''"in ''Japan Encyclopedia ...
prohibited the building of bridges over major rivers as a security measure. As depicted in contemporary ''
ukiyo-e
Ukiyo-e is a genre of Japanese art which flourished from the 17th through 19th centuries. Its artists produced woodblock prints and paintings
Painting is the practice of applying paint, pigment, color or other medium to a solid surfac ...
'' prints by artists such as
Hokusai
, known simply as Hokusai, was a Japanese ukiyo-e artist of the Edo period, active as a painter and printmaker. He is best known for the woodblock printing in Japan, woodblock print series ''Thirty-Six Views of Mount Fuji'', which includes the ...
, travelers crossed the river on
ferryboat
A ferry is a ship, watercraft or amphibious vehicle used to carry passengers, and sometimes vehicles and cargo, across a body of water. A passenger ferry with many stops, such as in Venice, Italy, is sometimes called a water bus or water taxi ...
s, as the current was too fast and too deep for fording. In cases of bad weather or high waters, they were forced to stay several days (or even several weeks) beside the river at
post stations (''shukuba'') such as
Mitsuke-juku
was the twenty-eighth of the fifty-three stations of the Tōkaidō. It is located in what is now the central part of the city of Iwata, Shizuoka Prefecture, Japan. The post station received its name, which means "with a view," because it was ...
.
The river was bridged shortly after the
Meiji Restoration
The , referred to at the time as the , and also known as the Meiji Renovation, Revolution, Regeneration, Reform, or Renewal, was a political event that restored practical imperial rule to Japan in 1868 under Emperor Meiji. Although there were ...
by road and railroad bridges. Today the
Tōkaidō Shinkansen
The is a Japanese high-speed rail line that is part of the nationwide Shinkansen network. Along with the Sanyo Shinkansen, it forms a continuous high-speed railway through the Taiheiyō Belt, also known as the Tokaido corridor. Opened in 1964, ...
express train
An express train is a type of passenger train that makes a small number of stops between its origin and destination stations, usually major destinations, allowing faster service than Local train, local trains that stop at most or all of the s ...
crosses the river in a few seconds.
Hydroelectric development
The potential of the Tenryū River valley for hydroelectric power development was realized by the
Meiji government
The was the government that was formed by politicians of the Satsuma Domain and Chōshū Domain in the 1860s. The Meiji government was the early government of the Empire of Japan.
Politicians of the Meiji government were known as the Meiji o ...
at the start of the 20th century. The Tenryū 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. However, the bulk of investment in hydroelectric power generation in the region was centered on the
Ōi 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 p ...
, and it was not until the
Taishō period that development began on the Tenryū River.
Private entrepreneur
Fukuzawa Momosuke founded the , which later became before it was nationalized into the pre-war government monopoly in 1938. The first dam on the main stream of the Tenryu River, the
Yasuoka Dam
Yasuoka Dam ( ja, 泰阜ダム) 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 irr ...
was completed in 1935. This was followed by the
Iwakura Dam in 1938. The
Hiraoka Dam
is a dam in Tenryū, Nagano Prefecture, Japan, completed in 1951. It is located on the Tenryū River upstream from the Sakuma Dam.
During the Second World War prisoners of war held at Tokyo #2D (Mitsushima) Prisoner of War Camp provided labo ...
was started in 1938, but completed until 1951 due to the start 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 opposin ...
.
After the end of World War II, the
American occupation authorities ordered the dissolution of Nippon Hassoden, which was divided into regional power companies. Central Japan came under
Chubu Electric Power
, abbreviated as Chuden in Japanese, is a Japanese electric utilities provider for the middle Chūbu region of the Honshu island of Japan. It provides electricity at 60 Hz, though an area of Nagano Prefecture uses 50 Hz. Chubu Electric ...
, which inherited the various dams and projects on the Tenryū River, all of which were located in Nagano Prefecture. For develop of the hydroelectric potential of the river in Shizuoka Prefecture, the government turned to the
Electric Power Development Company
The , operating under the brand name J-POWER, formerly , is an electric utility in Japan. It mainly produces electricity from coal and hydroelectric power stations. It also has a few wind farms and is currently building a nuclear plant in Ohma ...
. The new company, in part through
foreign aid
In international relations, aid (also known as international aid, overseas aid, foreign aid, economic aid or foreign assistance) is – from the perspective of governments – a voluntary transfer of resources from one country to another.
Ai ...
loans from the
United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and international security, security, develop friendly relations among nations, achieve international cooperation, and be ...
, and with the use of new dam technologies completed the huge
Sakuma Dam
The is a dam on the Tenryū River, located on the border of Toyone, Kitashitara District, Aichi Prefecture on the island of Honshū, Japan. It is one of the tallest dams in Japan and supports a 350 MW hydroelectric power station. Nearby a ...
in the 1956, at the time the 10th largest in the world. Further dams were completed in the 1960s and 1970s until the completion of the
Funagira Dam in 1976 brought development of the Tenryū River to a close.
Environmental consequences
These dams have altered the once abundant flow of the Tenryū River, and the lower reaches of the river near its mouth are almost dry.
This has had the unexpected effect of greatly increased erosion on the coastline of Shizuoka Prefecture, near Hamamatsu, especially around the
Nakatajima Sand Dunes
are located at the southern part of Hamamatsu, Shizuoka Prefecture at the Pacific Ocean coast of Japan. The sand dune area measures approximately 0.6 km from north to south and 4.0 km from east to west. It is considered one of Japan ...
. Meanwhile, at the same time, the vast amount of sand and silt trapped in various dams upstream have resulted in greatly lowered operational lives than originally projected. Methods to increase dredging in dams and to channel the silt and sand downstream to the ocean via a series of pipelines have been explored.
Tourism
The Tenryū River Valley is partially within the
Tenryū-Okumikawa Quasi-National Park
is a quasi-national park in the Tōkai region of Honshū in Japan. It is rated a protected landscape (category V) according to the IUCN. The park includes the Tenryū-kyō Gorge of the upper Tenryū River in Iida, Sakuma Dam and its surrounding ...
with the Tenryūkyō Gorge as a
nationally designated Place of Scenic Beauty in
Iida,
Nagano Prefecture
is a landlocked prefecture of Japan located in the Chūbu region of Honshū. Nagano Prefecture has a population of 2,052,493 () and has a geographic area of . Nagano Prefecture borders Niigata Prefecture to the north, Gunma Prefecture to the ...
,
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
.
The
Tenryū Hamanako Railroad Tenryū Hamanako Line Tenryū may refer to:
*Tenryū, Shizuoka, a city
*Tenryū, Nagano, a village
*Tenryū River
*Tenryū-ji, a temple
* , several ships
People with the name
*Tenryū Saburō (Saburo Wakuta, 1903-1989), Japanese sumo wrestler and martial arts fighter
* ...
runs along the lower reaches of the Tenryū River valley, whereas the
Iida Line
The is a Japanese railway line connecting Toyohashi Station in Toyohashi, Aichi with Tatsuno Station in Tatsuno, Nagano, operated by Central Japan Railway Company (JR Central). The line links eastern Aichi Prefecture and southern Nagano Prefe ...
runs along the upper reaches of the river into upper Shizuoka and Nagano prefectures, with a stop at
Sakuma Station near the namesake dam.
See also
*, led by
*
Japanese Alps
The is a series of mountain ranges in Japan which bisect the main island of Honshu. The peaks that tower over central Honshu have long been the object of veneration and pilgrimage. These mountains had long been exploited by local people for raw m ...
References
External links
Ministry of Land, Infrastructure and Transport (mouth)
{{DEFAULTSORT:Tenryu River
Rivers of Shizuoka Prefecture
Rivers of Aichi Prefecture
Rivers of Nagano Prefecture
Akaishi Mountains
Kiso Mountains
Japan Alps
Minami Alps National Park
Rivers of Japan