Agano River

Agano River
阿賀野川
Agano River; 阿賀野川
	Agano River and Taima Bridge of Ban'etsu West Line;
Native name	阿賀野川 (Japanese)
Location
Country	Japan
Prefectures	Niigata, Fukushima, Gunma
Physical characteristics
Source
• location	Mount Arakai, border of Fukushima Prefecture and Tochigi Prefecture
• elevation	1,581 m (5,187 ft)
Mouth
• location	Sea of Japan, Niigata Prefecture
• coordinates	37°57′48″N 139°07′46″E / 37.963224°N 139.129556°E
• elevation	0 m (0 ft)
Length	210 km (130 mi)
Basin size	7,710 km2 (2,980 sq mi)
Discharge
• average	451 m3/s (15,900 cu ft/s)
Basin features
Population	560,000

The Agano River (阿賀野川, Agano-gawa) is a river system in the Hokuriku region of Honshu, Japan. It is also called the Aga River or the Ōkawa River in Fukushima.^[1] It is designated as a Class A river.^[1]

The source of the river is Mount Arakai on the border of Fukushima and Tochigi prefectures. It flows to the north and meets the Nippashi River from Lake Inawashiro and the Tadami River in the Aizu Basin, and then turns to the west and falls into the Sea of Japan. The Agano River flows for 210 kilometers. It has a watershed area of 7,710 square kilometers.^[2] Approximately 560,000 people live in the basin area.^[1]

In 1964–1965, a chemical factory at Kanose village in Niigata Prefecture released methylmercury into the river and caused Niigata Minamata disease.^[3]

There are several hydroelectric power plants on the Agano River:

Inawashiro Power Plant (107.5 MW), constructed in several stages in 1899–1940. It was the site of Japan's first high-voltage, long-range power transmission line.
Numazawanuma Power Plant (43.7 MW), constructed in 1952.^[4] It was the first pumped-storage power plant in Japan.