Activities of the Iwate Office of Rivers and National Highways

The Iwate Office of Rivers and National Highways is doing construction workon the Kitakami River and some of its tributaries in Iwate Prefecture, and sand guard dams in the Hachimantai area.
Each branch office is responsible for a particular section of the KitakamiRiver.

Flood retarding basin at the confluence of the Kitakami and IwaiRivers


Flooding before the building of embankments	Flooding after the building of embankments

Floods beyond the embankments was prevented and the flood water was contained within the flood retarding basin.


Confluence of Kitakami and MatsuRivers in 1974	Confluence of Kitakami and MatsuRivers now

Strongly acidic water flowing from the former Matsuo Mine polluted the KitakamiRiver so much that, at one time, no fish lived in it. By implementing neutralization, the water quality of the river has improved dramatically to the point that salmon are coming up the river again.

※New neutralization facility at the former Matsuo Mine in the village of Matsuo.
Acid water is mixed with alkaline material to neutralize the water. Previously, we used to use slaked lime as the alkaline material. This is the same white powder used to draw lines on school grounds. Now we use cheaper calcium carbonate, which has been made possible by a new technology using iron bacteria.


Water is contained within the embankment.	Water is being pumped out from inside the embankment during a flood.


A sand guard dam built of wood in the Yakibashiri area, Nishine-machi	WaterPlaza in Kawasaki District (E boat race)	WaterPlaza in Ichinoseki District (checking the results of refurbishment made to provide easy access to all)


WaterPlaza in Mizusawa District (footpath)	WaterPlaza in Ishidoriya District (Study of aquatic animals)	WaterPlaza in Hanamaki District (boat landing point)

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