Yamba dam, Gumna prefecture, Japan

A historical case of resistance to a dam that would affect hotsprings and local livelihood in Gunma province. After a halt, works restarted and are scheduled to be finished in 2019


Yanba Dam is a dam project that is under construction in NaganoharaAgatsuma DistrictGunma PrefectureJapan. It is being built on the Agatsuma River, a tributary of the Tone River, which flows down through the metropolis of Tokyo, and the dam project is financed by Tokyo and the five prefectures through which the Tone River courses- Saitama, Chiba, Ibaraki, Tochigi, and Gunma. The project is currently under construction, with completion slated for 2019. Work on the dam was halted in 2009 when the Democratic Party of Japan (DPJ) came to power. It was halted as part of dozens of public works projects to be reconsidered. Planning for the dam began in 1947, and it was planned to be completed by 2015. The dam's construction has seen sustained local opposition and a ballooning budget.  Japan has suffered much flood damage, and after World War II dams were planned with the principal intention of protecting the metropolis from floods. Dams have therefore become particularly symbolic because they were favored as a means of flood control and power generation by Japan’s central planners, who have dammed almost every major river in the country. Amid Japan's rapid economic expansion of the 1960s and 1970s, population growth concentrated in cities, municipal water demand grew, and Tokyo and other major urban areas experienced water shortages. Clusters of dams were built upstream of the Tone River as an important facet of city planning, and Yamba Dam was promoted on the back of an emphasis on the necessity of water for domestic and industrial use.  The Agatsuma River, however, has the special characteristic of being fed from acidic rivers flowing down from the Kusatsu hot spring, which was held to make the construction of a concrete dam unfeasible.  Planning was halted but then restarted in 1965 after the construction of a plant in Kusatsu to neutralize the acidity of the water.

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Basic Data
NameYamba dam, Gumna prefecture, Japan
ProvinceGunma Prefecture
SiteNaganohara, Agatsuma District
Accuracy of LocationHIGH local level
Source of Conflict
Type of Conflict (1st level)Water Management
Type of Conflict (2nd level)Dams and water distribution conflicts
Transport infrastructure networks (roads, railways, hydroways, canals and pipelines)
Specific CommoditiesWater
Project Details and Actors
Project DetailsThe dam, which would dam the Agatsuma River, would flood an area of 316 hectares, require 422 households to relocate, and affect the lives of 1,100 residents.

Impounds Agatsuma River

Height 131 m

Length 336 m

Reservoir Total capacity 107,500,000 m³

Catchment area 707.9 km²

Surface area 304 hectares
Project Area (in hectares)304
Level of Investment (in USD)4,130,000,000 [1]
Type of PopulationRural
Potential Affected Population1,100 directly affected people
Start Date1965
Company Names or State EnterprisesShimizu Corporation from Japan
IHI Infrastructure Systems Co. from Japan
Tekken Corporation from Japan
Environmental justice organisations and other supportersYamba for Tomorrow Society

Association of Concerned Citizens for Yamba Dam project, http://yamba-net.org/eng/
The Conflict and the Mobilization
Intensity of Conflict (at highest level)MEDIUM (street protests, visible mobilization)
When did the mobilization beginPREVENTIVE resistance (precautionary phase)
Groups MobilizingLocal ejos
Local scientists/professionals
Forms of MobilizationObjections to the EIA
Official complaint letters and petitions
Public campaigns
Environmental ImpactsVisible: Large-scale disturbance of hydro and geological systems, Biodiversity loss (wildlife, agro-diversity), Surface water pollution / Decreasing water (physico-chemical, biological) quality, Reduced ecological / hydrological connectivity, Other Environmental impacts
OtherSubmergence of hotsprings
Socio-economic ImpactsVisible: Displacement, Loss of livelihood, Loss of traditional knowledge/practices/cultures
Project StatusUnder construction
Pathways for conflict outcome / responseUnder negotiation
Project temporarily suspended
Do you consider this as a success?Not Sure
Why? Explain briefly.The dam construction has been resumed and scheduled to be finished in 2019. Local population will be displaced and incomes and health benefits from hotsprings wiped out. the dam was planned for flood control and water for domestic, agricultural, industrial, and other uses. In line with changing social conditions in recent years, demand for water is trending downward and scientific doubts have been raised about the efficacy of the dam for flood control.
Sources and Materials

1997 Damming the Agatsuma River| An exploration of

changing space and place in Kawarayu, Japan

Michael Edward Gorton

The University of Montana
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Association of Concerned Citizens For Yamba Dam Project
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[click to view]

[1] Japan Times, 2009 - Main construction of Yanba Dam kicks off after 63-year wait
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Japan Today
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Other Documents

Site of the dam
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Blasting at dam site A puff of smoke emerges from the Yanba Dam site in Naganohara, Gunma Prefecture, where blasting work has begun after six decades of legal and political wrangling. | KYODO
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Hotsprings owner Takuji Toyoda, who owns a hot-springs inn, said of local dependence on Yamba Dam money, “The dam is like a drug.” Credit Ko Sasaki for The New York Times
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Meta Information
ContributorDaniela Del Bene, ICTA - UAB
Last update30/04/2017