Iyo River

Japanese: 伊予川 - いよがわ

...The alluvial fan near Yokogawara in Shigenobu Town is covered with a thick layer of gravel, forming an underground river, with almost no surface water in normal times. In the past, it was called the Iyo River, but it was renamed the Shigenobu River in recognition of the work of Adachi Shigenobu, a senior vassal of Matsuyama feudal lord Kato Yoshiaki, who renovated it around the Bunroku-Keicho period (1592-1615). After the Kato clan, the renovation work was passed on to the Gamo clan, Matsudaira clan, and the Matsuyama feudal lord, and it is not clear which parts were constructed by Shigenobu, but it is believed that before the renovation, the Iyo River ran from near Takai in Matsuyama City, south of its current course, through Aso, Yatsukura, Tokumaru, Desaku, and Omizo, and flowed into the Iyo Nada Sea south of Matsumae. ...

From the Dozan River

…The river originates in the western part of Besshiyama Village, Uma District, Ehime Prefecture, on the northern foot of Mount Kanmuriyama (1,732m) of the Ishizuchi Mountain Range, which forms the prefectural border with Kochi Prefecture, and flows eastward south of the Houou Mountain Range, extending for about 40 km to the Tokushima Prefecture border. In Tokushima Prefecture, it is called the Iyo River, and merges with the Yoshino River in Yamashiro Town, Miyoshi District. The river's name comes from the Besshi Copper Mine, but historical documents also refer to it as the Yamashiro River and Kinsha River. …

*Some of the terminology that refers to the Iyo River is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…重信町横河原付近に形成された扇状地は砂礫層が厚く堆積して天井川となり，平時は伏流しほとんど表流水がみられない。古くは伊予川と称したが，文禄･慶長期(1592‐1615)ころに松山藩主加藤嘉明の重臣足立重信が改修したことから，その功績をたたえ重信川と改められた。改修工事は，加藤氏の後，蒲生氏，松平氏と松山藩主に引き継がれ，どの部分が重信の施工かは定かではないが，改修前の伊予川は松山市高井付近から現在の流路の南方を麻生（あそう），八倉，徳丸，出作，大溝を経て松前（まさき）の南で伊予灘に注いでいたと考えられている。…