[Japan Water Agency / JWA] Water resources development of seven river systems.

[Japan Water Agency / JWA] Water resources development of seven river systems.

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Tone Canal – marking 50th Anniversary 30 January, 2019

Tone Canal Project has commemorated its 50th anniversary of management in 2018.

Outline of Tone Canal Project

To correspond to the tremendous increase of water demand along with the high economic growth started in the 1950s and also to stably intake irrigation water for the middle reaches of Tone River, Tone Canal Project was implemented as a comprehensive water resources development project.
The first role of the project was the conveyance of urban water developed at the groups of dams located in the upper reaches of Tone River such as Yagisawa Dam to Tokyo and Saitama via Musashi Canal and Ara River. The second role was to consolidate eight intake facilities, including Minuma-dai Canal and Kasai Canal built in Edo Period, all of which had respectively taken water directly from Tone River, and at the same time, to eliminate the unstable water intake due to degradation of river bed of Tone River and other causes and eventually supply farmlands in the middle reaches of Tone River with irrigation water stably and rationally. The third role was to use the excess water from Tone River and guide it into Sumida River to help purify the water for its quality improvement. The forth role was to drain the landside water in the surrounding areas of Musashi Canal to Ara River to reduce the flooding risk there.

The role of Tone Canal Management and Construction Office

Urban Water

From the canal, drinking water is supplied to a part of prefectures of Gunma, Saitama, and Tokyo with a total population of 13 million, and industrial water is supplied to approx. 700 offices and factories in Saitama Prefecture and Tokyo.

Asaka Canal (Settling pond)

Gyoda Canal (Intake)

Arakawa connecting water supply channel (Maeda sluice way)

Irrigation Water

Water from the canal is supplied to approx.23,300 ha of farmlands in Gunma and Saitama prefectures. In Saitama Prefecture, the water supply covers about half of the total paddy fields.

Suedasuga Barrage

Saitama Canal

Kasai Canal

Oura Canal

Gyoda Canal (Intake)

Arakawa connecting water supply channel (Maeda sluice way)

Water for Purification

Since 1965, water from Musashi Canal has been conveyed through Asaka Canal to Shingashi River and then Sumida River to be mixed with their original degraded water caused by the population increase of Tokyo and its vicinities to lower *BOD for purification.
*BOD: biochemical oxygen demand, an indicator to show the water pollution level

Asaka Canal (Settling pond)

Landside Water Drainage

To mitigate the inundation damage caused by heavy rains in the surrounding areas of Musashi Canal, rainwater flowing into small rivers in those areas is guided into Musashi Canal and drained to Ara River.

Major facilities of Tone Canal Management and Construction Office (Barrages and Canals)

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