Tadami River

It is one of the tributaries of the Agano River, which flows through Fukushima and Niigata prefectures and empties into the Sea of ​​Japan. The uppermost reaches are the Numajiri River, which originates in Oze Marsh on the border between Fukushima and Gunma prefectures, and the Yoppi River, which originates in Ozegahara. The two rivers join at the border between Fukushima, Gunma, and Niigata prefectures to become the Tadami River. It then flows north along the Fukushima-Niigata border, turns northeast in the western part of Tadami Town, Minamiaizu County, and empties into the Agano River (the name of the Agano River in Fukushima Prefecture) at the border between Yamato Town and Takasato Town in Kitakata City. Its river length is 137 kilometers. Its drainage area is approximately 2,900 square kilometers. The river forms a deep gorge, passing through Hiranamenotaki and Sanjonotaki at the northern end of Ozegahara, and many dam lakes, including Lake Okutadami (Ginzan Lake) and Lake Tagokura, are connected in the middle reaches. The abundant water volume has been utilized to develop power sources, and dams have been built from upstream to downstream, including Otsumata (a tributary), Okutadami, Otori, Tagokura, Tadami, Taki, Honna, Uwada, Miyashita, Yanaizu, and Katakado. From the middle reaches near Tadami Town to the downstream, the river forms a typical incised meandering course, with river terraces. The JR Tadami Line and National Route 252 run along the river, but the area is a heavy snow area, making it extremely difficult to maintain the road in winter. The central settlements of the towns of Tadami, Kaneyama, Mishima, and Yanaizu are located on the narrow terraces. The upper reaches are designated as Oze National Park, and the middle reaches are Echigo-Sanzan-Tadami Quasi-National Park and Tadami-Yanaizu Prefectural Natural Park (Fukushima Prefecture).

[Yoshio Nakamura]

"Tadami River - Its Nature and Power Development" by Asao Shiokawa (1964, Fukushima Minpo Publishing Bureau)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

福島、新潟県を流れて日本海に注ぐ阿賀野川(あがのがわ)の支流の一つ。最上流は福島・群馬県境にある尾瀬(おぜ)沼に発する沼尻川(ぬまじりがわ)と、尾瀬ヶ原に発するヨッピ川で、二つの川は福島・群馬・新潟県境で合流して只見川となる。さらに福島・新潟県境を北流し、南会津郡只見町西部で向きを北東に転じ、喜多方(きたかた)市山都(やまと)町と同市高郷(たかさと)町の境界で阿賀川（福島県での阿賀野川の呼び名）に注ぐ。流路延長137キロメートル。流域面積は約2900平方キロメートルに及ぶ。尾瀬ヶ原北端の平滑(ひらなめ)ノ滝、三条ノ滝を経て深い峡谷となり、中流部では奥只見湖（銀山湖）、田子倉(たごくら)湖をはじめとする多くのダム湖を連ねる。豊富な水量を利用して電源開発が進められ、上流から大津岐(おおつまた)（支流）、奥只見、大鳥、田子倉、只見、滝、本名(ほんな)、上田(うわだ)、宮下、柳津(やないづ)、片門(かたかど)のダムがつくられた。中流部の只見町付近から下流では河岸段丘を伴いながら典型的な穿入(せんにゅう)曲流路となる。川に沿ってJR只見線、国道252号が走るが、一帯は豪雪地帯であり、冬季交通路の維持は困難を極める。狭小な段丘上に只見・金山(かねやま)・三島・柳津の各町の中心集落が立地する。上流部は尾瀬国立公園、中流部は越後三山只見国定公園(えちごさんざんただみこくていこうえん)、只見柳津県立自然公園（福島県）に指定されている。

［中村嘉男］

『塩川朝夫著『只見川――その自然と電源開発』（1964・福島民報出版局）』

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