Kiyotsugawa River

A tributary of the Shinano River that flows through Yuzawa Town and Tokamachi City in southern Niigata Prefecture. It originates from Mt. Saburu (2,192 meters) on the border between Niigata and Nagano Prefectures, bypasses the foot of the Naeba volcano, and joins the Shinano River at Tazawa in the Nakazato district of Tokamachi City. It is 43.1 kilometers long. During the Edo period, the upstream area was famous for the Mikuni Three Post Towns (Asagai, Futai, and Mitsumata, Yuzawa Town), which were located along the Mikuni Highway. The Okukiyotsu Dam upstream is a multipurpose rockfill dam that stores water using surplus electricity and makes effective use of it, generating electricity and providing water for agricultural use. The 8-kilometer stretch from Yagisawa (Yuzawa Town) in the middle reaches to Koide (Tokamachi City) is carved into the pyroxene andesite of the Naeba volcano, forming cliffs, and is a scenic spot called "Kiyotsu Gorge" (a nationally designated place of scenic beauty and natural monument). At the mouth of the valley, there is Kiyotsu Gorge Hot Springs, and the river erodes the high terraces of the Tokamachi Basin, creating a wide river valley plain before joining the Shinano River.

[Hisao Yamazaki]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

新潟県南部の湯沢町、十日町市(とおかまちし)を流れる信濃川(しなのがわ)の支流。新潟・長野県境の佐武流(さぶる)山（2192メートル）に源を発し、苗場(なえば)火山山麓(さんろく)を迂回(うかい)して十日町市中里地区田沢で信濃川に合流する。延長43.1キロメートル。江戸時代、上流は三国街道筋で有名な三国三宿（浅貝、二居(ふたい)、三俣(みつまた)。湯沢町）があった。また上流の奥清津ダムは余剰電力で水を蓄えて有効に利用するロックフィル式多目的ダムで発電、農業用水に大きな効果をあげている。中流の八木沢(やぎさわ)（湯沢町）から小出(こいで)（十日町市）にかけての8キロメートル間は苗場火山の輝石安山岩をうがって断崖(だんがい)絶壁をなし、「清津峡」とよばれる景勝地（国指定名勝・天然記念物）。谷口には清津峡温泉もあり、柱状節理の渓谷と田代(たしろ)の七ツ釜(がま)で有名な支流釜川をあわせて、十日町盆地の高位段丘を侵食し、広い河谷平野をつくって信濃川に合流する。

［山崎久雄］

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