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🧳 | BS Asahi, "Tosa Kuroshio Railway & Dosan Line" on a trip to the new railway and superb view 4/29

Photo New Railroad / Scenic Trip "Tosa Kuroshio Railway & Dosan Line Crossing Kochi"

BS Asahi, "Tosa Kuroshio Railway & Dosan Line" on a trip to the new railway and superb view 4/29

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Yadoge-Nakamura-Saga Park-Kubokawa-Tosakurei-Anwa-Sagawa-Kochi, the Pacific Ocean and the Shimanto River, and in the satoyama, a spectacular competition of landscapes and cherry blossoms, and the scenery of cherry blossoms and famous places along the line such as Kochi Castle It is a trip across Kochi that gets drunk.

BS Asahi will be on April 2021, 4 (Thursday), on a trip to the new railroad and superb view, "Crossing Kochi by Tosa Kuroshio Railway & Dosan Line ... → Continue reading

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Shimanto River

Shimanto River(Shimantogawa) isKochiFlowing in the western part ofFirst-class riverIt is the main stream of the Watari river basin[2]..Total length 196km,WatershedArea 2186km2[1][Note 1].ShikokuIt is the longest river in the city.Since no large-scale dam has been built in the mainstream, "the last in Japan"Clear stream",AlsoKakita River-Nagara RiverWithJapan's three major streamsIt is called "one of".One hundred famous waters[3],100 unexplored areas in JapanHas also been selected.

47 Shimanto Rivers including tributariesSubsidence bridgeIn Kochi prefecture, there is a policy to preserve it as a living cultural heritage.1993Has been decided.


KochiTakaokaTsuno Town OfUnpenetrable mountainStarting from (Izuyama), many tributaries are gathered while meandering in an inverted S shape in the central and western part of Kochi prefecture.Shimanto CityでThe Pacific OceanPour into.Since the name is "Watari River" near the river mouth, the water system name is "Watari River system".

Clear stream two names

"The last in JapanClear streamSpeaking of, it has become so famous that it reminds me of "Shimanto River".River lawAbove1928から1994Until then, "Watarigawa" was the official name.189629 (Showa 1928) according to the old River Act of (Meiji 3)May 11Adopted "Watagawa" as the official legal name.1964Although it was "Watagawa" in the new river law of (39), it was 1994 (6).May 7Was renamed to "Shimanto River".Of the River ActFirst-class riverThis is the first time the name has been changed, and this is largely due to the fact that "Shimanto River" has become famous and recognized nationwide as "the last clear stream in Japan."[4]..However, in Kochi prefecture,RecognitionAlthough inferiorNiyodo RiverIn terms of water quality, the rank of the army goes up.

In the Edo period, it was sometimes called "Watarigawa" by writing "Shimanto River".Hoei5 years(1708)ofTosa storyIt is said that it is written as "Shimanto River Watarigawa".

On the other hand, looking at the names of the surrounding rivers, we headed toward Kyushu, which had a close relationship with the ancient times, and crossed the "Mukogawa (current name: Nakasuji River)" and "Watarigawa" to the city of Nakamura (Shimanto City), and behind it was "Ushiro". There is a "river", which can be thought of as a positional name.

There are various theories about the etymology of "Shimanto River" and it is not clear.[5][6].

  • It is a river where many rivers (Shimanto River) meet.
  • Ainu"Shi Mamut" (very beautiful) is a change.
  • Upstream and midstream tributaries, or upstream and midstreamTokawa Village OfJoint name place nameIs[7].
  • XNUMX stonestimberIt is said that there was a rich forest so much that it was washed away ten times.forestryIt is a thriving river[8].
  • Ainu word "Shimato" (GravelIt came from a lot of places).

On the other hand, there are the following two theories about the etymology of "Watagawa".[6].

Basin overview

The river that flows out of Mt. Irazu sews through the mountains and surrounds it.OgawaIt gradually becomes thicker and bigger.The river that collected the mountain fresh waterClear streamEnter in praise of clear water befitting the name of.In the Kubogawa basin, the surrounding areaRice fieldMoisturizes, butKubokawa StationNearbyShimanto TownThe sewerage system inside flows into the stream, making it difficult to call it a clear stream.After that, the Shimanto River became the Shimanto Town Iejigawa (commonly known as).Iejigawa Dam,1937Completion) for power generationdam(To be exact, because the bank height is as small as 8.0 meters and the fishway is well prepared.dam) Will pull out nearly half of the water.Especially when the amount of water in the upstream is small, the water disappears from the bottom of the river just below the dam, and the river may disappear. → The water of the damKuroshioIt is released to the Iyoki River (Iyoki River) that flows to.However, due to the existence of this dam, the water containing sewage in Shimanto Town hardly flows downstream, which is a factor that keeps the clear stream in the downstream area.

The once narrowed Shimanto River joins the Yusuhara River in Tanono, Shimanto Town.The Yusuhara River is a tributary with abundant water, and returns the main stream of the Shimanto River to a clear stream.However, the Yusuhara River has a Shimodo dam at the Tsuga power plant (,1944Completion, there is a dam with a bank height of 45.5 meters).A little downstream of the confluence, there is a torrent with a large head called Todoroki no Se.Next, in Showa, Shimanto Town, there is the largest Mishima in Chushu,camp siteIn addition to being maintainedSummer: からFall:ToSweetfishYou can see people fishing.Macrobrachium is a specialty and is fished, but it has decreased sharply.In Tokawa, Shimanto Town, from late April to early Maycarp streamer(Started in 49, it is the birthplace of carp streamers).

Originating in Ehime prefecture in Nishitosaekawasaki, Shimanto cityHiromi RiverIt merges with and further widens the river, creating a relaxed atmosphere.EgawasakiToSpa,CanoeThere are facilities in the area, and canoes come and go downstream from here, and campsites can be seen here and there.Shimanto River is in the basinSpring waterThere are many, and clean water is always supplied from everywhere except the tributaries.

A little down from Ekawasaki, it joins the Meguro River.In the upper reaches of the Meguro RiverNameko GorgeThere is a smooth riverbedbedrockIs a feature,Autumn leavesIt is crowded with tourists during this time.

Downstream flows along the edge of Shimanto city, the river width becomes wider,high tideSometimes seawater runs up.

Subsidence bridge

Shimanto RiverSubsidence bridgeIt is,Main stream22 pieces,TributaryThere are 47 including.Reinforced concrete constructionso,BalustradeIt is hung 2-3m above the normal water level.typhoon,(I.e.Sometimes by sinkingDriftwoodetcPierIt gets caught in such things and staysWater pressureIt prevents the entire bridge from being damaged and washed away.

The idyllic scenery created by the subsidence bridge, the river, and the surrounding mountains has become synonymous with the Shimanto River, and is often favored as a photo material.[9].

Phantom power development plan

1950 eraUntil Japan's power supplyHydropowerIt was suffering from chronic electricity shortages during the dry season in winter, as it was dominated by electricity.Against this background, even in the Shimanto River basin, there is a past where the construction of a large-scale dam and multiple power plants was planned as a set.Specifically, while constructing the Kajiwara River Dam, Akiha River Dam, and Watagawa Dam to mutually regulate water, water is drawn from the Matsuba River Dam to the Kure Power Station to generate electricity (16 kW), and the Sakaigawa Dam to generate electricity from Okitsu. It draws water to the place to generate electricity (10 kw).The wastewater from each power plant is directly drained without returning to the Shimanto River.Tosa BayWas planned to be poured into[10].

Shimanto River headwaters forest

Unpenetrable mountainIt is a forest centered on the headwaters of the Shimanto River at the northern foot of the mountain.Shikoku Karst Prefectural ParkLocated in the designated area ofShimanto River headwaters forestAsWater source forest XNUMX selectionsIs specified in[11].

MountainArea (ha)Altitude (m)Planted forest (%)Natural forest (%)Main tree speciesRestricted forestTypesFlow rate (m3 / day)
Unpenetrable mountain215740 - 13362080Cedar-Cypress-Fir-Red pine-Tsuga-Beech-KoyamakiWater source conservation forest, Health protection forest, academic reference forestrunning water(Shimanto River)1

Nearly 200 years oldNatural forestとNational forestManaged byConiferous forest OfPlantationOvergrown.The source isv kerbtalWith the rock surface and the green of the forestClear streamとLimestoneThe quality of the rock surface forms the beauty of the valley.

Location &
Oaza Funato, Tsuno-cho, Takaoka-gun, Kochi (Data is the designated year1995(7) April)

Main tributary


The Shimanto River has good water quality and is one of the clearest streams in Japan, and has been around for a long time.FishingHas been actively carried out.Naturaleel,Sweetfish,Gori(Tripletooth, Tripletooth goby), Tsugani (Black crab),Long-necked shrimpBesides seafood such asaonori seaweedIt is known as the production center of.The Shimanto River can be said to be one of Japan's leading rivers because many people make a living from river fishing.


The Shimanto River is one of the leading sweetfish producing areas in Japan, and the catch of sweetfish in the Shimanto River used to account for more than 6% of the total catch of sweetfish in Kochi Prefecture. Therefore, it is not uncommon for the catch of sweetfish in Kochi Prefecture to be the highest in Japan. Ta[12].1986By then, the catch has remained in the high 6,000t range, and although it has decreased once, it has increased.1991Peaked at 935t and then reduced catch2004Drastically reduced to 50t[13][14].. In August 2004, the Shimanto River Central Fisheries Cooperative (Representative Director Shizuo Okayama) and others who had a sense of crisis about this situationFishermanThey held a "symposium to restore sweetfish to the Shimanto River" and examined measures to protect sweetfish.Comparing the amount of sweetfish in stock by basin, the downward trend differs depending on the basin, and the Hata public market (Nakamura) in the downstream area, which had the largest amount of sweetfish in stock, showed a marked decline and no recovery trend.The reason for the sharp decrease in sweetfish isdamConstruction pollution, river gravel collection (currently prohibited),海The fry of sweetfish that went down to the sea died due to the rise in seawater temperature, ・ The number of fishermen increasedFishing gearIt is thought that they are intertwined in a complex manner with overfishing due to the development of[12][15], IsgravelBy collectionEstuaryFrom the devastation of the riverbed in the middle basin, especially the spawning grounds in the shallow water near the estuary, the decrease in hatcheries and the entire basinCypress,Cedar such asConifer OfPlanting treesbyMountain forestDecrease in water retention,eggThe overfishing of fallen sweetfish with.Gravel collection requires a permit from the fishery cooperative, a deposit, and money in return, but the fishery cooperative in this case does not necessarily specialize in river fishing in the Shimanto River.The traces of gravel collection are required to be backfilled by law, but because mountain soil is used, muddy water is generated and covers the pebbles on the riverbed to cover the pebbles of sweetfish.feedBecomemossDoes not grow and runs out of food.In addition, the fallen sweetfish form a flock and descend the flow, and are coldSpring waterHowever, the mountain soil blocks the spout.Hashimoto concludes that this combined with unseasonable weather led to a sharp decline in catches.[14].

Long-necked shrimp

Main inhabiting the Shimanto RiverLong-necked shrimpThere are three types: Macrobrachium formophyllum, Macrobrachium japonicum (Yamato Tenaga shrimp), and Tenaga shrimp.The annual catch of macrobrachium in the Shimanto River is around 30 tons, which is the second largest after eels and algae, and is an important fishery resource for fishermen.Compared to the eight major rivers in Kochi prefecture, the Shimanto river weighs around 8 tons, while the other seven rivers weigh less than 30 tons.

Macrobrachium formoides and Macrobrachium formoides are bilateral migratory species, and larvae that hatch in rivers descend to the salty areas of the estuary or the sea, and become juvenile shrimp and run up the river.The period is about one month.There are two groups of shrimp distributed in "brackish water" and "river still water, lake", and "brackish water" tenaga hatches and runs up like minami and hirate, but in "river still water, lake". Tenaga is thought to grow to zoea in eggs before being released and grow in the same environment as the parent shrimp.

In the flow of the Shimanto River with a flow length of 196 km, the flow distribution of the three species of macrobrachium is as follows.

  • Macrobrachium formoides-The range from the estuary to Ekawasaki.50km from the estuary.
  • Macrobrachium japonicum-range from Fuwa to Taisho.100km from the estuary.
  • Macrobrachium-downstream from Fuwa.8km from the estuary.

Traditional fishing method

The following traditional fishing methods have been practiced in the Shimanto River.

Pickled shiba
Long-necked shrimp,Shrimp,eel,fish
Bundle the branches with leaves and submerge them in water.After a few days, eels, eels, crabs, fish, etc. will settle in the gaps between the branches and leaves, so if you raise the shibazuke and shake it on a large net, the prey will fall.
Tenaga, eel
There are two types, one for eels and the other for eels, and nowadays, a tubular device made of vinyl chloride is used.For tenaga, use a diameter of about 10 x 40 cm, and for eel, use a diameter of about 4 x 70 cm, return it to the entrance, and put a net at the exit so that you can not exit once you enter.Same principle as Selvin.
A mortar-shaped hole of about 1.5 m is dug near the shore, and stones of about 20 cm are piled up in a few steps while creating a gap.Furthermore, pebbles of about 2 to 3 cm are piled up in a pyramid shape on it.The stone pile created in this way is called "Ishiguro".At high tide, Ishiguro is dismantled and the prey is driven into the enclosure.
Gorigara towing
Tripletooth goby
In the Shimanto River basin, the fry of tripletooth goby and tripletooth goby are called "gori", and this is a fishing method aimed at that gobi.Sazae OfshellPeople at both ends pull a rope that hangs hundreds of them from upstream to downstream, and the gori surprised by the light and sound of the turban shell is driven into the net and caught.GoriBoiledI will taste it.
Fire swing
At night, the ayu is driven into the net while shaking the lit torch near the river surface.At the same time, Ayu hits the surface of the water with a paddle and is surprised by the fire and sound and tries to escape.

Works dealing with Shimanto

"Late blooming sunflower-my life, renewal-Is a TV drama set in the Shimanto River.

Atsuo SaitoChildren's literature work "Gamba and otter adventure"(AlsoMovie adaptation) IsNiyodo RiverThe model is set in the Shimanto River.


Friendship river

Sumida RiverAnd since 1989.

Parallel traffic




[How to use footnotes]

注 釈

  1. ^ 2187km2There is also a document that says.
    Masatomo Umitsu (1982)Ehime OfterrainRegional division. "Study on regional division and regional setting in Ehime Prefecture".愛媛 大学Community Research Institute Report, Ser.A.18.5-15.


  1. ^ a b Water and Disaster Management Bureau, Ministry of Land, Infrastructure, Transport and Tourism Japanese river-China-Shimanto river Retrieved November 2019, 10.
  2. ^ Watari River Basin River Improvement Basic Policy - Ministry of Land, Infrastructure, Transport and TourismRiver Bureau
  3. ^ Shimanto River - One hundred famous waters Archived August 2011, 9, at the Wayback Machine. - Ministry of the Environment
  4. ^ Watari River Basin River Improvement Basic Policy P4.
  5. ^ "Please tell me the origin of the name of the river in Japan”. CTI Engineering Co., Ltd. 2019th of February 9Browse.
  6. ^ a b "History of rivers and people A survey report on paleogeography in the Shikoku region”. Shikoku Regional Development Bureau --Ministry of Land, Infrastructure, Transport and Tourism. P. 91. 2019th of February 9Browse.
  7. ^ "Yusuhara's clear stream ~ Shimagawa River ~ │ Yusuhara cheering party goes! !! │ Kumonoue Town Yusuhara ─ Yusuhara Town, Kochi Prefecture ─". www.town.yusuhara.kochi.jp. 2019th of February 9Browse.
  8. ^ Company, The Asahi Shimbun. “Kochi's Interesting Station Name Tour (below) -Nankoku Tosa, this time-Language Magazine: Asahi Shimbun Digital”(Japanese). Asahi Shimbun digital. 2019th of February 9Browse.
  9. ^ "Asahi cameraSeptember 2012 issue 9P-76P Rainy subsidence bridge Makoto Shiina(Asahi Shimbun)
  10. ^ "Electric Power Development Plan for Shimanto River 25 billion kilometers per year is comparable to Shinano River" Asahi Shimbun, November 11, 2, page 3
  11. ^ Shimanto River headwaters forest - Water source forest XNUMX selections - Forestry Agency
  12. ^ a b "2-2 River life and fishery resources-Shimanto Town Office". 2020th of February 5Browse.
  13. ^ Kensaku Higashi "Long-term catch fluctuations of sweetfish in the Shimanto River and recent characteristics"Fisheries Breeding," Vol. 58, No. 3, Japan Society for Fisheries Breeding, 2010, pp. 401-410, two:10.11233 / aquaculturesci.58.401,2020th of February 6Browse.
  14. ^ a b "Bises" Winter 2005 NO, 39 Katsuhiko Hashishita "Danger, the last clear stream Shimanto River"
  15. ^ "Japanese Communist Party October 2004, 10 (Monday) "Shimbun Akahata"". 2020th of February 5Browse.
  16. ^ "NHK Special "Tosa Shimanto River-Clear Stream, Fish and People-"”. NHK (August 2021, 5). As of August 4, 2021オ リ ジ ナ ルMore archives.2021th of February 5Browse.


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