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Pollution of the Yamato River, Japan

Yamato River was one of the dirtiest rivers in Japan with excessive BOD in the 1970s. After a series of recovery policies and actions, sweetfish ( "ayu") returned to the river in the 2000s.


The Yamato River used to be a familiar river widely known as a place of river play until the 1950s.  However, along with the high economic growth, the development of the watershed developed as a residential area in the Keihanshin metropolitan area.  When the industry was concentrated, the water quality deteriorated sharply due to household drainage, factory drainage, and livestock drainage.  Since the 1960s, the Yamato River's water quality had a poor condition making it unsuitable for the use of water and other hydrophilic and living creatures.  70% of the causes of pollution in the Yamato River were domestic wastewater. At that time, the sewerage coverage rate of households in the Yamato River basin was less than 20%. This means that domestic drainage flowed into the river without any treatment [1].

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Basic Data
Name of conflict:Pollution of the Yamato River, Japan
State or province:Osaka and Nara
Location of conflict:Osaka, Sakai, Yao, Nara, Yamatotakada, Yamatokōriyama
Accuracy of locationMEDIUM (Regional level)
Source of Conflict
Type of conflict. 1st level:Water Management
Type of conflict. 2nd level:Water access rights and entitlements
Landfills, toxic waste treatment, uncontrolled dump sites
Urban development conflicts
Aquaculture and fisheries
Specific commodities:Industrial waste
Domestic municipal waste
Project Details and Actors
Project details

Yamato River is about 68 kilometers in length. [8]

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Project area:107,000
Type of populationSemi-urban
Affected Population:2,000,000
Start of the conflict:1960
End of the conflict:2009
Relevant government actors:-Ministry of Land, Infrastructure, Transport and Tourism Kinki -Regional Development Bureau, Yamato River river office
-Osaka Prefectural Government
-Nara Prefecture
-Matsubara city
International and Finance InstitutionsLions Club from United States of America - They preside over Yamato River water quality improvement activity.
Environmental justice organizations (and other supporters) and their websites, if available:-Yamato River Clean Flow Revival Network (
-Yamato River Natural Sweetfish Study Group
-Kashiwara E-net (
Conflict & Mobilization
IntensityMEDIUM (street protests, visible mobilization)
Reaction stageMobilization for reparations once impacts have been felt
Groups mobilizing:Local government/political parties
Recreational users
Local scientists/professionals
Fisher people
Forms of mobilization:Community-based participative research (popular epidemiology studies, etc..)
Development of a network/collective action
Involvement of national and international NGOs
Public campaigns
Appeals/recourse to economic valuation of the environment
Research and administrative guidance; Setting administrative goals; Facility maintenance
Environmental ImpactsVisible: Biodiversity loss (wildlife, agro-diversity), Loss of landscape/aesthetic degradation, Surface water pollution / Decreasing water (physico-chemical, biological) quality
Potential: Food insecurity (crop damage), Soil contamination, Waste overflow, Oil spills, Groundwater pollution or depletion, Large-scale disturbance of hydro and geological systems, Reduced ecological / hydrological connectivity
Health ImpactsVisible: Accidents
Socio-economical ImpactsVisible: Loss of traditional knowledge/practices/cultures, Loss of landscape/sense of place
Project StatusIn operation
Conflict outcome / response:Environmental improvements, rehabilitation/restoration of area
Institutional changes
New legislation
Strengthening of participation
Application of existing regulations
Do you consider this an environmental justice success? Was environmental justice served?:Not Sure
Briefly explain:Improvement of water quality standards alone is not enough for the restoration of biodiversity. There are still many issues to be improved in order to realize the potentiality of the river as habitat, growth spawning, and hatching of more aquatic life [12].
It is considered extremely important to deepen the understanding and to strengthen the cooperation of various stakeholders in these areas and to make it an approach in the whole basin area [12].
Sources & Materials
Related laws and legislations - Juridical texts related to the conflict

Water environment improvement emergency plan (accessed on 12-04-2019)
[click to view]

Second Phase Water Environment Improvement Emergency Action Plan (accessed on 12-04-2019)
[click to view]

C Project Plan 2006 (Water Environment) (accessed on 12-04-2019)
[click to view]

Yamato River water environment improvement plan (accessed on 12-04-2019)
[click to view]

References to published books, academic articles, movies or published documentaries

[3] Yamamoto K. and Inoue H., Consideration on environmental improvement of river based on water quality survey of Hatsuse River (the Yamato River basin), Research note (accessed on 10-04-2019)
[click to view]

[2] Ueno H. et al, 2012, Confirmation of natural upswimming using otolith Sr/Ca ratio of sweetfish of Yamato River, Bulletin of Osaka University of Education, Third Division, Volume 61, 17-21, (accessed on 10-04-2019)
[click to view]

[10] Nagata Y., River maintenance fund furtherance business, "Mass runaway program of natural sweetfish in the urban river" Yamato River "", Achievement report (accessed on 12-04-2019)
[click to view]

Yoshiaki Tsuzuki & Minoru Yoneda, 2011, Pollutant runoff yields in the Yamato-gawa River, Japan, to be applied for EAH books of municipal wastewater intending pollutant discharge reduction

Journal of Hydrology 400(3-4):465-476.
[click to view]

Links to general newspaper articles, blogs or other websites

[6] Miyatake et al., Water quality pollution in Osaka bay, Group 1 (accessed on 10-04-2019)
[click to view]

[7] Osaka Prefectural Government, Make Yamato River Cleaner! (accessed on 10-04-2019)
[click to view]

[8] Sankei West, 6 April 2014, "Japan's dirtiest river = Yamatogawa" is reviving ... Figures of wild birds, figures of fish, and water quality improvement (accessed on 10-04-2019)
[click to view]

Yamato River water system (accessed on 12-04-2019)
[click to view]

Reason why Yamatogawa is dirty (accessed on 12-04-2019)
[click to view]

Eco Nara, Water pollution problem of Yamato River (accessed on 12-04-2019)
[click to view]

[1] River office of Yamato River, Ministry of Land, Infrastructure, Transport and Tourism Kinki Regional Development Bureau, Water environment of Yamato River - For improvement of water environment (accessed on 10-04-2019)
[click to view]

Yamatogawa Integrated Watershed Environment Improvement Project Evaluation
[click to view]

History of Yamato River
[click to view]

[9] Lions Club
[click to view]

[5] Kashiwara E-net, 20 August 2012, Sweetfish has backed to Yamato River (accessed on 10-04-2019)
[click to view]

Sweetfish has returned to Yamato River! (accessed on 12-04-2019)
[click to view]

[4] Yamato River Fresh Stream Revival Network, Revive! The Yamato River CFresh Stream Revival Project (accessed on 10-04-2019)
[click to view]

Other documents

State of the river since the 1970s (2) The water quality significantly deteriorated due to household drainage, rubbish and manure.
[click to view]

Children playing with water In the 1960s, many children used to be playing in the river.
[click to view]

Dead fish Many water quality accidents occur in the Yamato River water system.
[click to view]

Sweetfish's upstream In recent years, spawning of natural sweetfish and juvenile sweetfish have been confirmed annually downstream.
[click to view]

Collected sweetfish Collected sweetfish by Emeritus Professor Yoshikazu Nagata, Osaka University of Education
[click to view]

Otolith Otolith
[click to view]

Children playing with water By the 1960s, many children used to be playing in the river.
[click to view]

Yamato River Waterside Festival Every year since 2006, the waterside event takes place downstream, and the children enjoy water play.
[click to view]

Oil fence to prevent oil spill Related organizations cooperate and store oil fences and adsorption mats to prevent the spread of oil downstream and the spread of damage in river offices, civil engineering offices, municipalities, etc., and prepare for emergency response.
[click to view]

Kashiwara dam and fish path You can see the Kashiwara dam in the back. There is a new fishway in front.
[click to view]

Sumiyoshi Taisha's The Sumiyoshi Taisha's God Passage, which carries the shrine and crosses the Yamato River, was revived for the first time in 41 years in 2004.
[click to view]

Meta information
Contributor:EnvJustice, ICTA-UAB/Natsuka Kuroda, [email protected]
Last update08/05/2019
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