Dozan River

A tributary of the Yoshino River that flows east through eastern Ehime Prefecture. Its source is at the northern foot of Mount Kanmuri (1,732 meters) of the Ishizuchi Mountain Range, and it forms a V-shaped valley between the Ishizuchi Mountain Range to the south and the Houou Mountain Range to the north. It flows east through Niihama City and Shikokuchuo City, enters Tokushima Prefecture and becomes the Iyo River, and joins the Yoshino River in Yamashiro Town, Miyoshi City. It is about 50 kilometers long. Its drainage area is 282 square kilometers. Its main tributaries include the Saruta River, Kamio River, Nakano River, and Umatate River from the border with Kochi Prefecture. The river basin belongs to the Nagatoro Metamorphic Belt on the southern edge of the Median Tectonic Line, and is composed of crystalline schists such as sandstone schist, black schist, chlorite schist, and quartz schist. Metal resources have been developed here since ancient times, and the Sazare Mine (closed in 1979) and Besshi Copper Mine (closed in 1973) were located here. The Besshi, Tomisato, Yanase, Shingu, and Masatomo dams were built upstream to supply water to the Toyo region of Ehime Prefecture.

[Kazuo Fukaishi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

愛媛県東部を東流する吉野川の支流。源流は石鎚(いしづち)山脈冠(かんむり)山（1732メートル）の北麓(ろく)にあり、南の石鎚山脈と北の法皇(ほうおう)山脈の間をV字谷をなし、新居浜(にいはま)市、四国中央市を東流、徳島県に入って伊予川となり、三好(みよし)市山城(やましろ)町で吉野川に合流する。延長約50キロメートル。流域面積282平方キロメートル。おもな支流には高知県境側から猿田(さるた)川、上小(かみお)川、中の川、馬立(うまたて)川などがある。流域は中央構造線南縁の長瀞(ながとろ)変成岩帯に属し、砂岩片岩、黒色片岩、緑泥片岩、石英片岩などの結晶片岩類からなる。古くから金属資源の開発が行われ、佐々連(さざれ)鉱山（1979年閉山）、別子(べっし)銅山（1973年閉山）などがあった。愛媛県東予地方に水を供給するため、上流から別子、富郷(とみさと)、柳瀬(やなせ)、新宮(しんぐう)、政友の各ダムが建造された。

［深石一夫］

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