The is a river that crosses western
Aomori Prefecture
is a prefecture of Japan in the Tōhoku region. The prefecture's capital, largest city, and namesake is the city of Aomori. Aomori is the northernmost prefecture on Japan's main island, Honshu, and is bordered by the Pacific Ocean to the east, ...
,
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 ...
. It is in length and has a drainage area of . Under the
Rivers Act of 1964 the Iwaki is designated as a Class 1 River and is managed by the
Japanese Ministry of Land, Infrastructure, Transport and Tourism.
The Iwaki River is the longest river in Aomori Prefecture, and is the source of irrigation for the large-scale
rice
Rice is the seed of the grass species ''Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima
''Oryza glaberrima'', commonly known as African rice, is one of the two domesticated rice species. It was first domesticated and grown i ...
and
apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...
production of the prefecture.
The Iwaki River, in the
Tōhoku region
The , Northeast region, or consists of the northeastern portion of Honshu, the largest island of Japan. This traditional region consists of six prefectures (''ken''): Akita, Aomori, Fukushima, Iwate, Miyagi, and Yamagata.
Tōhoku retains a ...
north of the
Fukushima Daiichi Nuclear Power Plant
The is a disabled nuclear power plant located on a site in the towns of Ōkuma and Futaba in Fukushima Prefecture, Japan. The plant suffered major damage from the magnitude 9.0 earthquake and tsunami that hit Japan on March 11, 2011. The ...
, remains unpolluted by
radioactive materials after the
Fukushima Daiichi nuclear disaster
The was a nuclear accident in 2011 at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima, Japan. The proximate cause of the disaster was the 2011 Tōhoku earthquake and tsunami, which occurred on the afternoon of 11 March 2011 and ...
. Testing for
caesium-134
Caesium (55Cs) has 40 known isotopes, making it, along with barium and mercury, one of the elements with the most isotopes. The atomic masses of these isotopes range from 112 to 151. Only one isotope, 133Cs, is stable. The longest-lived radioisot ...
and
caesium-137
Caesium-137 (), cesium-137 (US), or radiocaesium, is a radioactive isotope of caesium that is formed as one of the more common fission products by the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nucl ...
is carried out and published on a bimonthly basis.
Geography
The source of the Iwaki River is at
Mount Ganmori () in the
Shirakami-Sanchi
270px, Shirakami Mountains Relief Map (with UNESCO World Heritage Site)
is a UNESCO World Heritage Site in the Tōhoku region of northern Honshū, Japan. This mountainous area includes the last virgin forest of Siebold's beech which once cover ...
region, a mountainous, unspoiled expanse of
virgin forest
''Virgin Forest'' is a 1985 Filipino period film directed by Peque Gallaga. A self-described B-movie, it stars Sarsi Emmanuel, who plays a barrio lass of Chinese ancestry; Miguel Rodriguez, as a Filipino-Spanish illustrado; and, Abel Jurado, wh ...
which spans both
Akita
is a Japanese name and may refer to:
Places
* 8182 Akita, a main-belt asteroid
* Akita Castle, a Nara period fortified settlement in Akita, Japan
* Akita Domain, also known as Kubota Domain, feudal domain in Edo period Japan
* Akita, Kumamoto, ...
and
Aomori
is the capital city of Aomori Prefecture, in the Tōhoku region of Japan. , the city had an estimated population of 278,964 in 136,457 households, and a population density of 340 people per square kilometer spread over the city's total area of ...
Prefectures.
The river flows eastward as a small mountain stream,
then joins several tributaries to form the scenic
Meya Ravine. The multi-purpose
Meya Dam is located in the upper reaches of the Iwaki River. The river turns sharply northward at the city of
Hirosaki
is a city located in western Aomori Prefecture, Japan. On 1 April 2020, the city had an estimated population of 168,739 in 71,716 households, and a population density of . The total area of the city is .
Hirosaki developed as a castle town fo ...
. The river crosses the broad
Tsugaru Plain, where it is joined by the
Aseishi,
Hira Hira may refer to:
Places
*Cave of Hira, a cave associated with Muhammad
* Al-Hirah, an ancient Arab city in Iraq
** Battle of Hira, 633AD, between the Sassanians and the Rashidun Caliphate
*Hira Mountains, Japan
* Hira, New Zealand, settlement n ...
, and
To rivers before emptying into
Lake Jūsan
, also known locally as is a brackish-water Estuary#Lagoon-type or bar-built, lagoon-type estuary located in the city of Goshogawara in Aomori Prefecture, Japan. It is the third-largest lake in Aomori Prefecture, after Lake Towada and Lake Ogawar ...
on the western coast of the
Tsugaru Peninsula
The is a peninsula in Aomori Prefecture, at the northern end of Honshū island, Japan. The peninsula projects north into the Tsugaru Strait separating Honshū from Hokkaidō. The western coast is on the Sea of Japan, while on its eastern coast ...
.
The mouth of the Iwaki River at Lake Jūsan is known as Mitoguchi.
Parts of the Iwaki River are protected as part of
Towada-Hachimantai National Park
is a national park comprising two separate areas of Aomori, Iwate, and Akita Prefectures, Japan. The Towada-Hakkōda area encompasses Lake Towada, Mount Hakkōda, and most of the Oirase River valley. The Hachimantai area includes Mount Hachim ...
,
Tsugaru Quasi-National Park
is a quasi-national park in Aomori Prefecture in the far northern Tōhoku region of Honshū in Japan. It is rated a protected landscape (category V) according to the IUCN. The park includes a number of discontinuous areas on Tsugaru Peninsula, i ...
, and five prefectural parks.
It flows through the following municipalities:
Nishimeya,
Hirosaki
is a city located in western Aomori Prefecture, Japan. On 1 April 2020, the city had an estimated population of 168,739 in 71,716 households, and a population density of . The total area of the city is .
Hirosaki developed as a castle town fo ...
,
Fujisaki,
Itayanagi,
Tsuruta,
Tsugaru Tsugaru (津軽) may refer to:
* Tsugaru, Aomori, a city of Aomori Prefecture, Japan
* Tsugaru Peninsula
* Tsugaru Strait, between Honshū and Hokkaidō
** Tsugaru Kaikyō Ferry, a ferry crossing this strait
* Tsugaru-jamisen, a traditional style of ...
,
Goshogawara
is a city located in Aomori Prefecture, Japan. , the city had an estimated population of 53,576 in 25,568 households, and a population density of 130 persons per km2. The total area of the city is .
Geography
Goshogawara occupies two discontinuo ...
,
Nakadomari, and
Shiura, where it enters Lake Jūsan.
Tributaries
*
*
*
*
*
*
*
*
*
History
Early history
The Iwaki River supported numerous villages as early as the
Jōmon period
The is the time in Japanese history, traditionally dated between 6,000–300 BCE, during which Japan was inhabited by a diverse hunter-gatherer and early agriculturalist population united through a common Jōmon culture, which reached a c ...
(14,000 – 300 BCE) as evidenced by numerous
shell mounds. The river was revered as the "mother of the Tsugaru Plain" throughout its early history.
The Iwaki River region, located in the vast northern
Mutsu Province
was an old province of Japan in the area of Fukushima, Miyagi, Iwate and Aomori Prefectures and the municipalities of Kazuno and Kosaka in Akita Prefecture.
Mutsu Province is also known as or . The term is often used to refer to the comb ...
, came under the control of the central government throughout much of 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. ...
(794 – 1185). The
Northern Fujiwara
The Northern Fujiwara (奥州藤原氏 ''Ōshū Fujiwara-shi'') were a Japanese noble family that ruled the Tōhoku region (the northeast of Honshū) of Japan during the 12th century as their own realm. clan, based in
Hiraizumi
is a town located in Nishiiwai District, Iwate Prefecture, Japan. , the town had an estimated population of 7,408 and a population density of in 2,616 households. The total area of the town was . It is noted for the Historic Monuments and Site ...
in present-day
Iwate Prefecture
is a prefecture of Japan located in the Tōhoku region of Honshu. It is the second-largest Japanese prefecture at , with a population of 1,210,534 (as of October 1, 2020). Iwate Prefecture borders Aomori Prefecture to the north, Akita Prefectur ...
, controlled the rich trade of the
Port of Tosa in present-day Goshogawara. Despite the loss of control of much of Japan later in the Heian period, the court maintained some level of military presence in Mutsu. This control ended when the Northern Fujiwara were conquered by
Minamoto no Yoritomo
was the founder and the first shogun of the Kamakura shogunate of Japan, ruling from 1192 until 1199.Nussbaum, Louis-Frédéric. (2005). "Minamoto no Yoriie" in . He was the husband of Hōjō Masako who acted as regent (''shikken'') after his ...
(1147 – 1199) and clans of the
Kantō region
The is a geographical area of Honshu, the largest island of Japan. In a common definition, the region includes the Greater Tokyo Area and encompasses seven prefectures: Gunma, Tochigi, Ibaraki, Saitama, Tokyo, Chiba and Kanagawa. Slight ...
, and the Iwaki River region came under the direct control of the
Kamakura shogunate
The was the feudal military government of Japan during the Kamakura period from 1185 to 1333. Nussbaum, Louis-Frédéric. (2005)"''Kamakura-jidai''"in ''Japan Encyclopedia'', p. 459.
The Kamakura shogunate was established by Minamoto no Y ...
. By the mid-Kamakura period the
Akita clan
The was a Japanese samurai clan of northern Honshū that claimed descent from Abe no Sadato of the Abe clan. The Akita clan was originally known as the . In the Kamakura period, they were installed in the Tsugaru district of Mutsu Province to ...
ruled the area, and the
ranch
A ranch (from es, rancho/Mexican Spanish) is an area of land, including various structures, given primarily to ranching, the practice of raising grazing livestock such as cattle and sheep. It is a subtype of a farm. These terms are most often ...
es, agriculture of the Iwaki River region, and trade with the
Ainu. The Port of Tosa was destroyed in an enormous
tsunami
A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explo ...
in 1340. The Akita clan was eventually defeated by the
Nanbu clan
The was a Japanese samurai clan who ruled most of northeastern Honshū in the Tōhoku region of Japan for over 700 years, from the Kamakura period through the Meiji Restoration of 1868. The Nanbu claimed descent from the Seiwa Genji of Kai Pr ...
during the
Sengoku period
The was a period in History of Japan, Japanese history of near-constant civil war and social upheaval from 1467 to 1615.
The Sengoku period was initiated by the Ōnin War in 1467 which collapsed the Feudalism, feudal system of Japan under the ...
(1467–1573).
Numerous
castles
A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word ''castle'', but usually consider it to be the private fortified r ...
were constructed along the Iwaki River, notably
Hirosaki Castle
is a city located in western Aomori Prefecture, Japan. On 1 April 2020, the city had an estimated population of 168,739 in 71,716 households, and a population density of . The total area of the city is .
Hirosaki developed as a castle town for ...
.
Edo period
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 ...
quickly established stability in the Iwaki River region at the beginning of 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 ...
(1603 – 1868). The course of the Iwaki River was diverted and developed for agricultural as part of an effort by the Tokugawa shogunate for the increase of agricultural output across Japan.
The original path of the upper reaches of the Iwaki River remains unclear. There were originally two rivers in the area of the
castle town
A castle town is a settlement built adjacent to or surrounding a castle. Castle towns were common in Medieval Europe. Some examples include small towns like Alnwick and Arundel, which are still dominated by their castles. In Western Europe, ...
of Hirosaki, and at some point in the late 17th century they were diverted into a single river, the Iwaki.
The
Tsugaru Domain
Hirosaki Castle, the seat of the Hirosaki Domain
, also known as , was a '' tozama'' feudal domain of Edo period JapanRavina, Mark. (1998) ''Land and Lordship in Early Modern Japan,'' p. 222 It is located in Mutsu Province, in northern Hon ...
began large-scale work on the Iwaki River in the same period to open new
rice paddies
A paddy field is a flooded field of arable land used for growing semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in southern China, associated with pre-Aust ...
on the Tsugaru Plain. The Iwaki River had a lively
riverboat
A riverboat is a watercraft designed for inland navigation on lakes, rivers, and artificial waterways. They are generally equipped and outfitted as work boats in one of the carrying trades, for freight or people transport, including luxury un ...
trade, and rice storehouses controlled by the Tokugawa shogunate were built in Sanzeji (present-day
Akita City
'Autumn field' is the capital Cities of Japan, city of Akita Prefecture, Japan, and has been designated a Core cities of Japan, core city since 1 April 1997. , the city has an estimated population of 305,625, 136,628 households and a population d ...
),
Fujisaki, Itayanoki (present-day
Itayanagi), and Kanagi. The rice was collected at the
Port of Jūsan in present-day
Goshogawara
is a city located in Aomori Prefecture, Japan. , the city had an estimated population of 53,576 in 25,568 households, and a population density of 130 persons per km2. The total area of the city is .
Geography
Goshogawara occupies two discontinuo ...
at the mouth of the river at Lake Jūsan. From there the rice was transported to
Ajigasawa on the
Sea of Japan
The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it h ...
to be shipped to the
Edo
Edo ( ja, , , "bay-entrance" or "estuary"), also romanized as Jedo, Yedo or Yeddo, is the former name of Tokyo.
Edo, formerly a ''jōkamachi'' (castle town) centered on Edo Castle located in Musashi Province, became the ''de facto'' capital of ...
capitol.
Modern period
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 ...
in 1868 the construction of railroads in Aomori Prefecture, specifically the
Ōu Main Line
The is a railway line in Japan, operated by the East Japan Railway Company (JR East). It connects Fukushima Station through Akita Station to Aomori Station. Since the opening of the Yamagata Shinkansen on July 1, 1992, the Fukushima–Yamag ...
, ended the comparatively inefficient riverboat trade along the Iwaki River in favor of the movement of agricultural cargo by rail. In the 20th century the central government of Japan took direct control of riverworks to prevent flooding on the Iwaki, a chronic problem recorded as early as the Edo period. The was officially approved by the Diet of Japan in 1917.
Large-scale flood prevention works began shortly afterwards. The mouth of the river at Lake Jūsan, Mitoguchi, suffered frequent blockage between November and April due to strong winds and waves, a feature of the harsh climate of northern Aomori Prefecture. Projects to remove blockages of the river at Mitoguchi began in the Meiji period, but caused a change in water levels on the upper reaches of the river. The controversy over construction work at Mitoguchi became increasingly controversial, resulting in violent clashes between residents of the upper and lower regions of the Iwaki River in 1890.
A
pier
image:Brighton Pier, Brighton, East Sussex, England-2Oct2011 (1).jpg, Seaside pleasure pier in Brighton, England. The first seaside piers were built in England in the early 19th century.
A pier is a raised structure that rises above a body of ...
to prevent blockage was excavated and constructed at the mouth of the river between 1930 and 1946. The passageway allows year round access to the river.
Numerous bridges were also constructed across the Iwaki River to improve transportation in Aomori Prefecture.
Use
![TsugaruPeninsulaJpLandsat](https://upload.wikimedia.org/wikipedia/commons/2/22/TsugaruPeninsulaJpLandsat.jpg)
The Iwaki River is a major source of water for
irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
. Numerous irrigation canals have been built across the Tsugaru Plain, and the Iwaki supports the
paddies for vast production of rice in Aomori Prefecture.
The river is called "the mother of Tsugaru" for this reason.
Aomori Prefecture is the largest producer of apples in Japan,
and the upper zone of the Iwaki River provides irrigation for an extensive network of orchards, especially in the area of Hirosaki City.
The commercial fishery of
ayu
Ayu or AYU may refer to:
* Ayu (given name)
* Ayu sweetfish (''Plecoglossus altivelis''), a species of smelt
* ''Ayu'', a local name for the African manatee
* Ayu (singer) or Ayumi Hamasaki, Japanese singer
* Ayu Islands, a small archipelago in I ...
is no longer held on the Iwaki, but its lower reaches and mouth of the river at Mitoguchi are a source of commercial
clam
Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two she ...
production.
Fauna and flora
Upper
The source of the Iwaki, in the Shirakami-Sanchi, is home to large virgin expanses of the ''buna'',
Siebold's beech. This area, which is also the source of the
Oirase River
The is a river located in eastern Aomori Prefecture, in the Tōhoku region of northern Japan.
__NOTOC__
The Oirase River is the only river that drains Lake Towada, a large caldera lake that lies on the border of Aomori and Akita Prefectures. Th ...
, is designated a
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It ...
World Heritage Site
A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...
. The upper reaches of the Iwaki are a
spawning
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquati ...
area of the ayu, also known as the sweetfish, and
ugui, the Japanese dace. The area is also known as a home for the
kingfisher
Kingfishers are a family, the Alcedinidae, of small to medium-sized, brightly colored birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species found in the tropical regions of Africa, Asia, and Oceania, ...
and the
Asian house martin
The Asian house martin (''Delichon dasypus'') is a migratory passerine bird of the swallow family Hirundinidae. It has mainly blue-black upperparts, other than its white rump, and has pale grey underparts. Its three subspecies breed in the Hima ...
.
Tsuruyoshi, a creeping species of the
common reed
''Phragmites australis'', known as the common reed, is a species of plant. It is a broadly distributed wetland grass that can grow up to tall.
Description
''Phragmites australis'' commonly forms extensive stands (known as reed beds), which may ...
and the
branched bur-reed can be found in this area.
Middle
The middle reaches of the river, also home to the apple orchards of Aomori, are noted for long belts of
willow
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
s. The
northern goshawk
The northern goshawk (; ''Accipiter gentilis'') is a species of medium-large bird of prey, raptor in the Family (biology), family Accipitridae, a family which also includes other extant diurnal raptors, such as eagles, buzzards and harrier (bird) ...
, the
nosuri, a species of the
common buzzard
The common buzzard (''Buteo buteo'') is a medium-to-large bird of prey which has a large range. A member of the genus ''Buteo'', it is a member of the family Accipitridae. The species lives in most of Europe and extends its breeding range across ...
, and the
black kite
The black kite (''Milvus migrans'') is a medium-sized bird of prey in the family Accipitridae, which also includes many other diurnal raptors. It is thought to be the world's most abundant species of Accipitridae, although some populations have ...
have breeding grounds in the area.
Lower
The lower reaches of the Iwaki were once a vast
reed bed
A reedbed or reed bed is a natural habitat found in floodplains, waterlogged depressions and
estuaries. Reedbeds are part of a succession from young reeds colonising open water or wet ground through a gradation of increasingly dry ground. As ...
. Numerous bird species are protected in this area, including the
marsh grassbird, also known as the
Japanese swamp warbler, and the
Japanese reed bunting
The Japanese reed bunting or ochre-rumped bunting (''Emberiza yessoensis'') is a bird in the family Emberizidae. The species was first described by Robert Swinhoe in 1863.
It is found in Manchuria, Korea and Japan. Its natural habitats are tem ...
, both of which are threatened by
habitat loss
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
. The
mākuosamu and ''
Dytiscidae
The Dytiscidae – based on the Greek ''dytikos'' (δυτικός), "able to dive" – are the predaceous diving beetles, a family of water beetles. They occur in virtually any freshwater habitat around the world, but a few species live a ...
'' species of
beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s are indigenous to the area. The
least weasel
The least weasel (''Mustela nivalis''), little weasel, common weasel, or simply weasel is the smallest member of the genus '' Mustela,'' family Mustelidae and order Carnivora. It is native to Eurasia, North America and North Africa, and has bee ...
, common in other areas of the world, is increasingly rare in the Iwaki River region and may become a protected species. The
yamato shijimi, a species of clam used in
Japanese cuisine
Japanese cuisine encompasses the regional and traditional foods of Japan, which have developed through centuries of political, economic, and social changes. The traditional cuisine of Japan (Japanese: ) is based on rice with miso soup and other ...
, is common in the brackish area of the mouth of the Iwaki River at Mitoguchi and Lake Jūsan.
Footnotes
:A.
Mount Iwaki
is a stratovolcano located in western Aomori Prefecture, Tohoku, Japan. It is also referred to as and less frequently, due to its similar shape to Mount Fuji. With a summit elevation of and a prominence of it is the highest mountain in Ao ...
() is not the source of the Iwaki River. While the mountain and river are located in the Tsugaru region and share a common name, Mount Iwaki is located to the west of the middle reaches of Iwaki River, far north of the source of the river.
References
External links
岩木川: ライブカメラLive camera views of the Iwaki River at locations along the course of the river. Updated every 30 minutes. Japanese Ministry of Land, Infrastructure, Transport and Tourism.
{{Authority control
Rivers of Aomori Prefecture
Rivers of Japan