Entō Bunsui

Cross section of an Entō Bunsui

Schematic floor plan of an Entō Bunsui. Water distribution in the ratio 3: 1: 4 for the water channels marked with the numbers 1 to 3. Legend: Arrows show the direction of flow of the water, asterisks mark the source point of the water pumped up.

Entō Bunsui ( Japanese 円 筒 分水 , German roughly cylindrical water distribution basin , regionally also: 円 形 分水 , Enkei Bunsui , English Circular Tank Diversion or Water Diversion Facility ) is a component of the Japanese irrigation system that is used in agriculture and that enables an exact and continuous water distribution.

overview

The irrigation system consists of two cylinders of different sizes, one inside the other. The inner cylinder serves as a siphon that pumps (ground) water upwards. The water carried upwards flows evenly over the edge of the inner cylinder and in this way enters the outer cylinder. From the outer cylinder, the water is transported to the agricultural areas via irrigation channels, the amount of water being distributed in a fixed ratio. In order to divide the amount of water, the outer cylinder is divided into circular segments of different sizes by means of slides.

For a long time, the distribution of the amount of water used for irrigation in wet rice cultivation caused disputes. From the Taishō period , water pipes and distribution systems began to be designed and built throughout Japan. The first method used for water transport was the differences in altitude in the landscape. In 1934, water began to be pumped from the ground to the surface in the prefectures of Fukushima and Nagano . The first water distribution systems in Nagano were already similar to the Entō Bunsui, but were still designed in a radial pattern so that the amount of water could not yet be efficiently divided. It was only through the use of two cylindrical tubes and the use of hydrostatic pressure to pump the water that the first Entō Bunsui was built in 1942 in the prefecture of Nara . One of the first water distribution basins in Kuji is now registered as a material cultural asset .

Selected water distribution basins

• Shikazeki water distribution basin in Shiojiri , Nagano Prefecture , completed in 1934, part of the Shinano water system
• Water distributor no. 12 Oto nashi iro ( 音 無 井 路 十二 号 分水 , for example “noiseless groundwater well”) in Taketa , Ōita prefecture , completed in 1934, part of the Ōno water system
• Nishiten Ryūkansen suiro water distribution basin ( 西天 竜 幹線 水路 円 筒 分水 群 ) in Ina , Minamiminowa and Minowa , Nagano Prefecture , completed in 1939, part of the Tenryū water system
• Nika ryōyōsui Kuji water distribution basin ( 領 ヶ 領 用水 久 地 円 Wass 分水 ) in the Takatsu district of Kawasaki , Kanagawa Prefecture , completed in 1941, part of the Tama water system
• Yokoi Seisui ( 横 井 清水 ) in Ina , Nagano Prefecture , established at the end of the 19th century, part of the Tenryū water system
• Tsūjun yōsui Ozasa ( 通 潤 用水 小 笹 円 形 分水 ) water distribution basin in Yamato , Kamimashiki County , Kumamoto Prefecture , completed in 1956, part of the Midori and Sasahara water systems
• Asaka Canal ( 安 積 疏水 , Asaka sosui ) in Sukagawa , Fukushima Prefecture , year of completion unknown, part of the Abukuma water system

One of the largest water distribution basins is at Ishibuchi Dam ( 石 淵 ダ ム ) on the Hisawa plain. The diameter of the inner cylinder is 24 m, that of the outer 31.5 m with a water volume of 16 m³ / s.

photos

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  Oto nashi iro in Taketa , Oita Prefecture

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  Entō Bunsui in the Kuji district of Nara . The water was drained for restoration purposes.

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  Yokoi Seisui Entō Bunsui

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  Enkei Bunsui at the Tsūjun Aqueduct

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  Water distribution basin on the Asaka Canal

Individual evidence

1. ↑ 二 ヶ 領 用水 久 地 円 筒 分水 . Cultural Affairs Office , 2014, accessed December 24, 2014 (Japanese). 
2. ↑ 胆 沢 平野 土地 改良 区 と は ／ 挨 拶 ・ 沿革 ・ 組織 ・ 事業 . (No longer available online.) 胆 沢 平野 土地 改良 区 , Archived from the original on December 24, 2014 ; Retrieved December 24, 2014 (Japanese). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  

Web links

• Ozasuki Oza: 円 筒 分水 ド ッ ト ・ コ ム . 2014, accessed December 24, 2014 (Japanese, National Water Distribution Basin Database). 
• Clark Parker: the tokyo files 東京 フ ァ イ ル . February 8, 2014, accessed December 24, 2014 . 
• Ento-Bunsui Water Diversion Facility 円 筒 分水 . The Southern Kanto Region Promotional Committee for Educational Tours, accessed December 24, 2014 . 
• Google Maps with well-known Entō Bunsui