Obitsu River
   HOME

TheInfoList



OR:

The is a river in Kimitsu, Kisarazu, and Sodegaura,
Chiba Prefecture is a prefecture of Japan located in the Kantō region of Honshu. Chiba Prefecture has a population of 6,278,060 (1 June 2019) and has a geographic area of . Chiba Prefecture borders Ibaraki Prefecture to the north, Saitama Prefecture to the n ...
, Japan. The river is in length and has a drainage area of .


Description

The Obitsu emerges from the densely forested valleys around Mount Motokiyosumi () in the
Bōsō Hill Range The is a mountain range on the Bōsō Peninsula of Chiba Prefecture, Japan. The highest point in the Bōsō Mountain Range is at Mount Atago, with an altitude of . The hill range runs from roughly in a line from Mobara or Ōamishirasato to ...
and empties into
Tokyo Bay is a bay located in the southern Kantō region of Japan, and spans the coasts of Tokyo, Kanagawa Prefecture, and Chiba Prefecture. Tokyo Bay is connected to the Pacific Ocean by the Uraga Channel. The Tokyo Bay region is both the most populous ...
. It is the second largest river in Chiba Prefecture after the
Tone River The is a river in the Kantō region of Japan. It is in length (the second longest in Japan after the Shinano) and has a drainage area of (the largest in Japan). It is nicknamed Bandō Tarō (); ''Bandō'' is an obsolete alias of the Kant ...
(). The upper reaches of the Obitsu meander through Kimitsu, the middle of the river runs more directly through Kisarazu, and the lower reaches form and estuary and a triangular delta in Sodegaura, an area known as the Banzu Tidal Flats. The Obitsu then turns briefly west back into Kisarazu to empty into Tokyo Bay. The tidal flats of the Obitsu host numerous species of birds and
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...
s. In 2012 an
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
endangered species crab, '' Uca lactea lactea'', was discovered at the mouth of the river, and may be the northernmost habitat of the crab in Japan. The
Koito River The is a river in Futtsu and Kimitsu, Chiba Prefecture, Japan. The river is in length and has a drainage area of . The Koito is the third-longest river in Chiba Prefecture, and under the Rivers Act of 1906 the Koito is designated as a Class 2 ...
, similarly to the Obitsu, emerges from Mount Motokiyosumi, flows east across
Bōsō Peninsula The is a peninsula that encompasses the entirety of Chiba Prefecture on Honshu, the largest island of Japan. It is part of the Greater Tokyo Area. It forms the eastern edge of Tokyo Bay, separating it from the Pacific Ocean. The peninsula cover ...
, and empties into Tokyo Bay. The two rivers are the longest in the western region of the peninsula.


Kamegawa Dam

The Kamegawa Dam was built near the
Kazusa-Kameyama Station is a passenger railway station in the city of Kimitsu, Chiba Prefecture, Japan, operated by the East Japan Railway Company (JR East). Lines Kazusa-Kameyama Station is the eastern terminus of the Kururi Line, and is located 32.2 km fr ...
on the
JR East The is a major passenger railway company in Japan and is the largest of the seven Japan Railways Group companies. The company name is officially abbreviated as JR-EAST or JR East in English, and as in Japanese. The company's headquarters ar ...
Kururi Line on the upper part of the Obitsu River in 1979. The dam forms an artificial lake, Lake Kameyama. The lake is the largest
reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including control ...
in Chiba Prefecture with a diameter of .亀山湖


Tributaries


History


Early history

The Obitsu River supported a rich population in 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 ...
(ca. 14,000–300 BC) as evidenced by large-scale ''kaizuka'' midden, or shell mounds. The shell mounds of Chiba Prefecture are the largest in Japan, and the , along the Obitsu in the Gion District of Kisarazu, dates from the mid-Jōmon period. While there is some evidence of large-scale settlement along the Obitsu in the
Yayoi period The started at the beginning of the Neolithic in Japan, continued through the Bronze Age, and towards its end crossed into the Iron Age. Since the 1980s, scholars have argued that a period previously classified as a transition from the Jōmon p ...
(300 BC–250 AD), the entire eastern Bōsō area was again richly populated in the Kofun period (250–538).


Edo period

Inland water transportation to connect the agriculture-rich middle and upper regions of the Obitsu developed slowly and reached its zenith on the Obitsu River in 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 character ...
(1603–1868). The
Tokugawa shogunate The Tokugawa shogunate (, Japanese 徳川幕府 ''Tokugawa bakufu''), also known as the , was the military government of Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in ...
showed strong interest in products from
Kazusa Province was a province of Japan in the area of modern Chiba Prefecture. The province was located in the middle of the Bōsō Peninsula, whose name takes its first ''kanji'' from the name of Awa Province and its second from Kazusa and Shimōsa provinc ...
. The shogunate excavated and straightened the meandering middle part of the Obitsu River to develop new
paddy field 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 ...
s for the cultivation of
rice Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly '' Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and ''Porteresia'', both wild and domestica ...
and ''renkon'' lotus root. Like the Yōrō River and the Koito River, small
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 u ...
s were used on the Obitsu.
Rice Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly '' Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and ''Porteresia'', both wild and domestica ...
, as the ''nengu''
tax A tax is a compulsory financial charge or some other type of levy imposed on a taxpayer (an individual or legal entity) by a governmental organization in order to fund government spending and various public expenditures (regional, local, or n ...
tribute to the Tokugawa shogunate, passed from the former Kururi Region of Kimitsu to the port at Kisarazu, typically crossing a distance of . Charcoal, an essential product in the Edo capital, was produced in the central region of the Boso Peninsula, and was another essential trade product on the Obitsu. In the most prosperous period of the Obitsu River, there were 35 riverboats active in trade, and most were property of individual villages along middle and upper reaches of the river. The mouth of the Obitsu River became a lively trade center, as the Port of Kisarazu had exclusive rights to sea traffic between the western Bōsō Peninsula and 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 ...
capital.


Modern period

The lower parts of the Obitsu River along Tokyo Bay were developed in the early 20th century to support growing industrial facilities along Tokyo Bay., and this area ultimately became an important part of the Keiyō Industrial Zone. Despite the large industrial development of the lower part of Obitsu River, the middle and upper ranges of the continue to be used extensively for rice and vegetable production. The Obitsu River in the area around the Nagasuka, Kisarazu has historically been used for large-scale '' renkon'' lotus root cultivation. The low, damps areas of the river have been developed into rice paddy fields and fields for the production of lotus root. The renkon of the area became popular in the Tokyo area at the end of the Edo period, and remain in cultivation today.木更津市歴史通り(8)ハス田
Additionally, the shallows at the Banzu Tidal Flats formed the largest area of ''
nori Nori is a dried edible seaweed used in Japanese cuisine, made from species of the red algae genus '' Pyropia'', including ''P. yezonesis'' and '' P. tenera''. It has a strong and distinctive flavor, and is often used to wrap rolls of sushi o ...
'' seaweed cultivation in the Tokyo Bay region.


Recreation


Kimitsu

*Lake Kameyama has developed tourist facilities. The lake is ringed by a pedestrian path, has a family campground, and is the only spot in Chiba Prefecture for lure fishing. Lake Kameyama is accessible from the JR East Kururi Line
Kazusa-Kameyama Station is a passenger railway station in the city of Kimitsu, Chiba Prefecture, Japan, operated by the East Japan Railway Company (JR East). Lines Kazusa-Kameyama Station is the eastern terminus of the Kururi Line, and is located 32.2 km fr ...
.亀山湖・亀山ダム


Kisarazu

*The ''renkon'' lotus fields of Kisarazu can be accessed from , 358 Gion, Kisarazu, Chiba. The park is a 10-minute walk from the
JR East The is a major passenger railway company in Japan and is the largest of the seven Japan Railways Group companies. The company name is officially abbreviated as JR-EAST or JR East in English, and as in Japanese. The company's headquarters ar ...
Kururi Line Gion Station.


Sodegaura

*Clamming and shell gathering are popular in the Banzu Tidal Flats of the Obitsu.


Footnote

*Other sources place the river at .


External links


小櫃川河口干潟(おびつがわ かこうひがた)亀山湖


References

{{Rivers of Japan Rivers of Chiba Prefecture Tourist attractions in Chiba Prefecture Rivers of Japan