Shigenobu River

A river that flows through the Matsuyama Plain in the center of Ehime Prefecture. It is a first-class river. It is 36 km long and has a drainage area of ​​445 square km. It originates at the southern foot of Higashimikatagamori (1,233 meters) in the center of Takanawa Peninsula, and flows into the Iyo Nada Sea in the southern part of Matsuyama City. The drainage basin is full of granite collapsed areas, and the river carries a lot of material. In addition, the Inai River, Haishi River, Kutani River, and Tobe River, which join the Shigenobu River on the left bank, have large fault scarps along the Median Tectonic Line and landslide areas of the Ishizuchi Tertiary Formation in their drainage basins, and all of them form alluvial fans and diluvial plateaus around the plains. For this reason, the Shigenobu River is one of the roughest rivers in Shikoku, and has been subject to constant flooding since ancient times. In the early modern period, Adachi Shigenobu (?-1625) of the Matsuyama domain renovated this rough river, and it is said that the river has been called Shigenobu River since 1625 (Kan'ei 2).

[Kazuo Fukaishi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

愛媛県中央部の松山平野を流れる川。一級河川。延長36キロメートル、流域面積445平方キロメートル。高縄(たかなわ)半島中央の東三方ヶ森（1233メートル）南麓(なんろく)に発し、松山市南部で伊予灘(なだ)に注ぐ。流域は花崗(かこう)岩の崩壊地が多く、河川運搬物が多い。また左岸で重信川に合流する井内川、拝志(はいし)川、久谷(くたに)川、砥部(とべ)川は、中央構造線に沿う大断層崖(がい)と石鎚(いしづち)第三紀層の地すべり地帯を流域にもち、いずれも平野周辺に扇状地、洪積台地を形成する。このため重信川は四国でも有数の荒れ川で、古くから洪水が絶えなかった。近世初期に松山藩の足立重信(あだちしげのぶ)（？―1625）がこの荒れ川を改修したので、1625年（寛永2）以来重信川と称するようになったとされる。

［深石一夫］

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