Update:April 1, 2010

1) Jinzu River

1.JlNZU RIVER AND KAMIOKA MINES

Toyama prefecture, through runs the Jinzu River, is located in the central Part of Japan. It faces the Sea of Japan and is bordered by the Tateyama Mountains to the south and Toyama Bay to the north. There are 5 comparatively large rivers and 22 small and medium size rivers running through the prefecture. About 30% of all prefectural land is natural forest. The abundant natural surroundings and green-rich setting make Toyama Prefecture one of the so-called "best places to live" in Japan. (Fig.1-1)

However, the prefecture has a saddening past recounted by the once itai-itai disease. The government, the people and the private sector locked hands in a determined fight to overcome this evil. Based on this experience, much attention is given to hormonizing environmental protection and industrial development, in what should be a center region in the upcoming "new age on the Sea of Japan".
The itai-itai disease (acute cadmium poisoning) occurred in a limited area of some 1,500 hectares along the Jinzu River basin. The Jinzu River runs through the center of the prefecture, originating in the Northern Alps, near Yarigatake, Hodakadake and Yakedake, which separate Toyama Prefecture from Gifu Prefecture.
At its upper reaches, the river merges with the Hirayu and Kamata River, before merging with the Sugoroku River and flowing into the Asaida Dam. The central section or the river cuts through the Kamioka mining region which extend approximately 10 km east-west and 20 km nouth-south. In its lower reaches, it merges with the Miyakawa water system which runs down from the highlands near Kanidera between Gifu and Toyama Prefectures. It finally flows into the Toyama Plains after passing through Jinzu River Dams No. 1, 2, and 3 of the Hokuriku Electric Power Company, and then pours into Toyama Bay.
The cadmium which caused the itai-itai disease came from the Kamioka Mines along the central section of the Jinzu River on the Gifu Prefecture side. The outbreak occurred about 30 km downstream from the mines in Osawano and Fucyumachi, This is rice growing area. Water collected by Jinzu River Dam No 2 is used on the Gyugakubi water system for farming (Fig.1-2).