New Shinano River

This is a diversion created at the top of the riverbank of the Shinano River, which runs through the center of the Echigo Plain. It is also called the Okozu Diversion. It stretches from Okawazu (Okawazu) in the Bunsui district of Tsubame City to Nozumi Coast in the Teradomari district of Nagaoka City, and has a length of about 10 km, a width of 720 m, and a maximum discharge capacity of 200,000 cubic meters. Okawazu is located at the top of the riverbank of the delta where the main stream of the Shinano River is closest to the coast. The diversion was planned by Honma Kazuemon and others of Teradomari Town in 1716 (Kyoho 1), and generations of people tried to make it a reality, but it was never realized due to the difficult construction work that required digging between the Yahiko Mountains and the Nishiyama Mountains. Even at the end of the Edo period and into the Meiji era, neighboring farming villages repeatedly petitioned the shogunate or the Diet, but were unsuccessful. In 1909 (Meiji 42), the project was made a national project, and it took 15 years until it was finally completed in 1923 (Taisho 12). Upon completion, 50,000 hectares of wet rice fields in Sushima were transformed into dry fields, saving coastal residents from flooding and facilitating the construction of Niigata Port. To commemorate its completion, cherry trees were planted around the three-kilometer embankment and Okawazu Water Diversion Park, which are now a popular spot for flower viewing. There is also a museum in the park on the Komon side.

[Hisao Yamazaki]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

越後(えちご)平野の中央を貫流する信濃川の州頂部につくられた分水。大河津分水(おおこうづぶんすい)ともいう。燕(つばめ)市分水(ぶんすい)地区の大川津(おおかわづ)（大河津）から長岡(ながおか)市寺泊(てらどまり)地区の野積(のづみ)海岸に至る延長約10キロメートル、幅720メートル、最大流水量20万立方メートルの放流能力をもつ。大川津は信濃川本流がもっとも海岸に近よる三角州の州頂部に位置し、分水は1716年（享保1）すでに寺泊町の本間数右衛門(ほんまかずえもん)らによって計画され、その後代々実現に努めたが、弥彦(やひこ)山地と西山山地間を掘削しなければならぬ難工事で、ついに実現しなかった。幕末から明治に入っても、近郷関係農村で数度も幕府あるいは国会に請願を繰り返したが成功せず、1909年（明治42）国家事業として実現することになり、1923年（大正12）まで15か年を要してようやく完成した大工事であった。この完成によって州島の5万ヘクタールの湿田が干田と化し、沿岸住民を洪水から救い、新潟港の築港を促進した。完成記念に築堤3キロメートルと大河津分水公園一帯に植えられたサクラは、いまは花見の名所になっている。閘門(こうもん)側の公園内に資料館もある。

［山崎久雄］

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