[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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Nanma Dam body construction will start in full swing soon! 30 October, 2020

The Japan Water Agency will begin construction of Nanma Dam, which will be the core facility of the Omoigawa Development Project in Kanuma City in the central western part of Tochigi Prefecture. On June 30, 2020, we unveiled the bid information for "Nanma Dam Body Construction Work" and started the procedure for placing orders for the construction works. On this occasion, we would like to express our sincere gratitude to those who relocated from their hometown, who sold us their properties, the local community residents, and to all the related organizations for their great cooperation and understanding.
Our plan is that the contractors will be decided in November, and we will start the construction of the dam body. We will proceed with the construction while giving consideration to the conservation of the surrounding environment and the safety of the area toward the completion of the project in 2024. We will appreciate your continued understanding of this project and cooperation in it.

Construction site(July)

Rendering

Outline of Omoigawa Development Project

In this project, Nanma Dam is to be built on the Nanma River which is a tributary of the Omoi River. This project purposes are to control flood and to develop water resources efficiently by connecting the Kurokawa River and the Oashi River, which are tributaries of the Omoi River, with Nanma Dam using the aqueducts, allowing adjustable use of water resources among those rivers.

Outline of the water intakes into the canals leading to the dam and supply water from the dam to the rivers via the canals

Legend of Nanma Dam

Type
Face type concrete type
Rockfill dam
Height
86.5 m
Dam volume
2.4 million m³
Gross reservoir capacity
51 million m³
Effective storage capacity
50 million m³

Legend of canal

Kurokawa Aqueduct
Extension:approx. 3km,
Max. conveyance volume 8 m³/s
Oashigawa Aqueduct
Extension:approx. 6 km,
Max. water conveyance volume 20 m³/s

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