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M e k o n g Wa t c hMekong Watch Briefing Paper
Pak Mun Dam
Pak Mun Dam:
Run of River Dam Height 17 m Length 300 m
Installed Capacity 136 Megawatts
Location: Hua Hew Village, Khonjiam District, Ubon Rachathani Province（at the mouth of the Mun River, 5.5 km upstream from its confluence with the Mekong）
Project owner：the Electricity Generating Authority of Thailand（EGAT）

Problems of the Pak Mun Dam
The Pak Mun Dam can teach societies of theMekong Basin a variety of lessons on dam developmenton the Mekong River. It was said that there would befewer environmental and social impacts from this dam, thefirst “run of river” dam built on the Mekong, but in reality,
it has had a big impact, resulting in a drastic decrease in
the amount of fish resources in the basin. Destruction of
the ecosystem has led to poverty among the affectedvillagers. Projects failing to take the lifestyles of thevillagers into account have led to a strong backlash against
development, sparking large oppositional movements thatwill go down in the history of the Thai peoples’movements. It was also an economic failure, ascompensation initially budgeted for resettlement wasinsufficient, and none had been allotted for fisheries. It
required a strong people’s movement to receive
compensation, which in spite of inflating the costs of thedam tremendously has still been unable to make up for
their loss of livelihood.
This dam was a project not only of the Thai nation, butalso supported by the World Bank, so the failure of thisdevelopment project has been noted widely around theworld.
The first survey for the Pak Mun Dam was done by
France in 1967, downstream from the dam’s present
location. Its construction was postponed at that time, but after a subsequent survey in the 1980’s the decision wasmade to reduce the dam’s height from 113 to 108 meters above sea level. Proposals to reduce the impact on thevillagers were accepted and in May 1990, the Thai government gave approval at a cabinet meeting for the dam’sconstruction. Work began in 1991 and the dam was completed in 1994.
The Pak Mun Dam and the World Bank
The Pak Mun Dam was built with partial funding from the World Bank.1 From the time its construction began,residents working in fisheries, ichthyologists and NGOs were opposed to it, pointing out the effects it would
1

The project received U.S.$54 million as the Third Power Project（3）of the International Bank for Reconstructionand Development (IBRD).

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have on many of the migratory fish that make their way up the Mekong to the Mun River. When the World Bank
Board of Governors met to decide on funding in 1991, the representatives from the US, who had conducted theirown environmental impact assessment, as well as from Germany and Australia were opposed to it, with Canada
abstaining, but Japan’s representatives reportedly applied pressure to approve funding. In a follow-up assessmentof the project in 1998, the World Bank claimed that resettlement implementation and outcomes were “among thebest experiences with resettlement among Bank-assisted projects.”2 This drew criticism from around the globe.
From 1999, local people organized a large-scale movement demanding natural environmental restoration as
opposed to compensation, attracting broad support. Attention was also drawn to the dam as an example of aWorld Bank development project failure, and it was selected as a case for investigation by the World
Commission on Dams, which conducted a reevaluation of large dams worldwide.
The Mun River and Its Fish
Under the influence of the tropical monsoon, northeastern
Thailand has a distinct rainy season and dry season. The name“Mun” means “heritage.” “Pak Mun” denotes the area around themouth of the Mun River, so that was chosen for the dam’s name. The
water level of the rivers in the lower reaches of the Mekong Basinrises during the rainy season due to the increased amount of rainfall.
Many fish migrate upstream during that season, including into theMun River. Also, during the dry season, when severe drying occurs,
the fish return to the main stream of the Mekong, where water is stillabundant. (See figure to the right.)
The lower reaches of the Mun River feature many rapids andpools, and the middle reaches have extensive inundated forests,
making it a suitable place for fish in the middle reaches of theMekong Basin to spawn. More than 270 fish species have been
confirmed there in the past. 3 Fish are known to be particularly
abundant in the lower reaches of the Mun River, and although it is
nowhere near the ocean, about 60 villages in the basin make theirliving through fishing rather than farming.
Fish migration in the Mekong(Source: MRC).

The Effects of Underestimating
The Mun River was one of the important spawning areas for fish migrating up from the Mekong River. The
Pak Mun Dam is thought to have had a tremendous impact on fish in the lower reaches of the Mekong River, but
this had not been investigated at all prior to its construction.
Moreover, compensation amounts awarded with regard to the dam’s construction have swollen to nearly threetimes the original estimates.
Planning vs. reality of the Pak Mun Dam compensation and mitigation plan
Mitigation
Resettlement
Displacement
Agriculturalland inundated project for fishcosts（baht）（baht）
Planned-394.77 million 248
house- -holds (1985)(1988)
Actualhouse- 706
house- 305.55 million
1113.1 million 943
holds (1994)
holds (1994)(1999)(1995-1998)（Source: Pak Mun Dam, Mekong River Basin, Thailand: A WCD Case Study. 2000）

The villagers were strongly opposed to the dam’s construction after it had gotten underway. The Thaigovernment, however, would not review the project, so they changed their position to demand additional
Recent Experience With Involuntary Resettlement: Thailand—Pak Mun.” World Bank Operations Evaluation
Department. 2 June 1998.
3 According to a strategic environmental assessment by the Mekong River Commission (MRC).
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compensation and continued protesting. In 1995, the Thai government approved an award of 30,000 baht per
year to each family for the three-year period of the dam’s construction as compensation for fisheries. It wasn’t
until 1999, though, that they finally paid the 90,000 baht award (30,000 baht in cash, with 60,000 baht depositedin agricultural cooperatives). The number of households compensated was 3,966, bringing the total awarded to395.6 million baht.
The fish ladder built and aquatic resource recovery program instituted after the dam was completed have
proven ineffective, and the region’s fisheries have been ruined. The villagers have made their living as temporary
migrant workers in the cities, but the effects of the currency crisis of 1997 caused many of the villagers to lose
their work and return to their villages. There are increasing demands for more compensation among the villagers
who have been unable to make a living through fishing. A cabinet meeting of the second term of the ChuanAdministration in 1998 made a decision not to compensate villagers repeatedly for dam development projects
when they had already been compensated.
The villagers lost hope in the government, but judging it difficult to recover their livelihoods with thecompensation received, they renewed their calls for the dam’s removal. In March 1999, a group of several
thousand of them, including villagers affected by other dams, occupied the Pak Mun Dam site, creating the Mae
Mun Man Youn (Eternal Mun River) Village as a forum for discussions. This action brought attention to themovement from all over the country. In addition, with construction of a new large dam in America halted,
opposition to large dams was spreading globally, and attention was drawn to the Pak Mun Dam as an example ofa failure of a World Bank-funded project, so the villagers’ call for the dam’s removal was became known
worldwide. At that time, the number of households claiming to have been affected by the Pak Mun Dam hadrisen to about 6,000.
Test Opening of Sluice Gates and Re-evaluation
In 2001, the Thai Rak Thai Party, which supported Thaksin Shinawatra, declaring its concern for theimpoverished, won an overwhelming election victory. Prime Minister Thaksin approved the short-term openingof the dam’s sluice gates for survey purposes4 and ordered the local Ubon Ratchathani University to investigate
and document the effects. After the sluice gates were opened, the river environment improved dramatically, andfish catches increased. The villagers and NGOs worked jointly on “Thai Baan (village people) Surveys,” andpresented the results of social surveys based on the villagers’ knowledge. This received wide support fromeminent researchers.
The university research team proposed keeping
the sluice gates open year round on a trial basis
for five years, citing figures on the degree of thevillagers’ impoverishment and the lack of any
economic merits of the dam’s electricity
production, documenting recovery of fisheryresources through opening the sluice gates, andnoting that the gates’ opening would have noimpact on the electric power supply, but would
improveeconomic
conditions
fortheimpoverished people in the villages. The Thaigovernment, however, did not adopt the proposal
and decided to open the sluice gates for only fourmonths each year (from July to October).5
This way, while claiming to mitigate theimpacts on fishery resources, they began opening
the sluice gates at times that did not match thefish’s migratory period.6
4Initially, the sluice gates were to be opened for just a few months, but in accordance with the wishes of both theresidents and Ubon Ratchathani University, they remained open from June 2001 to November 2002.
5 According to local NGOs, the four-month gate-opening period was set for the rainy season, when the Mekong’swater level below the dam rises enough to eliminate the difference in water levels between the dam anddownstream, and almost no electricity can be generated anyway.
6 Drawing on local residents’ knowledge, the peak of the upward fish migration at the mouth of the Mun Riveroccurs from the end of May into early July, and their migration downstream takes place around November.

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Annual Four-month Sluice Gate Opening
The first four-month sluice gate opening in 2003 did nothing to improve the local fisheries, so the next year, in2004, the villagers requested the government to change the timing of the gate opening to coincide with the fish
migration periods. The cabinet approved a plan to open the gates from May 1 to August 31, and had them opened
in June that year.
In 2007, however, the opening of the sluice gates was stopped. After the political turmoil that started with
Prime Minister Thaksin’s downfall and brought Prime Minister Surayud to power in a coup d’etat, the newcabinet decided to discontinue it, saying there had been 20,000 signatures petitioning the government to close thesluice gates. Negotiations between the villagers and the researchers and government representatives supportingthe closure dragged on, with a committee for support of Pak Mun Reservoir operations established in 2008 in
Ubon Ratchathani Province, after which the decision was made to open the sluice gates for four months. A newcriterion was established to the effect that when the amount of water flowing past a certain observation point
exceeded certain levels, the sluice gates were to be opened, but with continued changes in administrations, thisarrangement has proven to lack substance.
Once again in 2011, lobbying by the villagers resulted in committees of experts being established andproposals made for opening the sluice gates, but the Thai government has not accepted them.
Recommendation:
As developments along the Mekong River negatively affect fish in the whole lower Mekong basin, recovery of
the natural environment in the Mun River will have great significance for preserving ecosystems in the entire
Mekong River. The Thai government should follow the recommendations presented by Ubon Ratchathani
University in 2002, i.e., full opening of the gates for five years.

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