The Pak Mun Dam ( th, เขื่อนปากมูล, , ) is a

barrage dam A barrage is a type of low-head, diversion dam which consists of a number of large gates that can be opened or closed to control the amount of water passing through. This allows the structure to regulate and stabilize river water elevation up ...

and run-of-the-river hydroelectric plant 5.5 km west of the confluence of the Mun and

Mekong The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annual ...

Rivers in Khong Chiam District, Ubon Ratchathani Province,

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

. It was constructed by the

Electricity Generating Authority of Thailand The Electricity Generating Authority of Thailand (EGAT) ( th, การไฟฟ้าฝ่ายผลิตแห่งประเทศไทย; ) is a state enterprise, managed by the Ministry of Energy, responsible for electric power g ...

(EGAT) with support from the

World Bank The World Bank is an international financial institution that provides loans and grants to the governments of low- and middle-income countries for the purpose of pursuing capital projects. The World Bank is the collective name for the Interna ...

at a total cost of US$240 million, and completed in 1994.

Environmental impact

The project has been criticized for adverse effects on the fisheries of the Mun River, insufficient compensation payments to affected villagers, and failure to produce the projected power output. The immediate impact of the

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, a ...

was to flood 117 km² of land and displace families. The original plan estimated the displacement of 262 families. In the end, 912 families were displaced and 780 households lost all or part of their land. In all, around 25,000 villagers claim to have been affected by the dam. Protests have been staged at the dam site and outside Government House in

Bangkok Bangkok, officially known in Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estimated populatio ...

and critics have called for the dam to be immediately decommissioned. , EGAT had paid out 377.7 million

baht The baht (; th, บาท, ; currency sign, sign: ฿; ISO 4217, code: THB) is the official currency of Thailand. It is divided into 100 ''satang'' (, ). The issuance of currency is the responsibility of the Bank of Thailand. Society for Worldw ...

in relocation compensation, plus 356.9 million baht for loss of fisheries with unsettled fisheries claims amounting to an additional 200 million baht. In response to concerns about the dam's likely impact on fisheries on the Mun River, a

fish ladder A fish ladder, also known as a fishway, fish pass, fish steps, or fish cannon is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration as well as movem ...

was incorporated into the scheme to allow

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

into the Mun River to spawn. The fish ladder has been "unsuccessful". A report from the

World Commission on Dams The World Commission on Dams (WCD) existed between April 1997 and 2001, to research the environmental, social and economic impacts of the development of large dams globally. The self-styled WCD consisted of members of civil society, academia, the ...

found that of 265 fish species previously found in the Mun River, at least 50 had disappeared and numbers of others had declined significantly. The fish catch decreased by 60–80%. It is uncertain what proportion of this decrease is attributable to the dam, and what proportion to other factors. In response to protests, the government opened the dam gates temporarily in June 2001. Subsequently, a study by

Ubon Ratchathani University Ubon Ratchathani University (UBU) ( Thai, มหาวิทยาลัยอุบลราชธานี) was established as a campus of Khon Kaen University, Thailand, in 1987. It gained independent university status in 1990. ] History ...

recommended keeping the gates open for a further five years, and a study by Living River Siam recommended decommissioning the dam. Instead, the Thai Cabinet decided to close the gates for eight months each year from November 2002.International Rivers
Pak Mun Dam
/ref> As part of a two-year study to review the development effectiveness of large dams, the

(WCD) commissioned the Thailand Development Research Institute (TDRI) to conduct a case study on the Pak Mun Dam. TDRI's report, published in 2000, concluded that, "...EGAT over-stated the case of project benefits and did no justice to the method of benefit-cost analysis in exaggerating the value of net gains in power production and in claiming irrigation benefits on invalid grounds."

Environmental impact

References

Further reading