Detailed map of the Mekong River Basin (Opens in new browser window)

This is one of up to 10 case studies of dams in major river basins around the world to be undertaken by the Commission in preparation of its June 2000 final report. The report will provide a framework for future decision-making on dams, which epitomise the many conflicts at the heart of debates over sustainable development. However, it should be noted that the Commission is not judicial in nature and will not adjudicate on disputes over dams. The WCD case studies will underpin that final report by illustrating 'lessons learned' in terms of the myriad impacts -- positive and negative -- of dams on people, the environment, and economies.

The 4200-kilometre-long Mekong starts life in Tibet and passes through Yunnan province in China and a small section of Burma before forming the border between Thailand and Laos. It enters Cambodia at the magnificent Khone waterfalls before slowing its pace in the nine arms of the low-lying Mekong delta in southern Vietnam, and finally discharges into the South China Sea. The Mekong is the third largest river in Asia, after the Yangtze in China and the Ganges in India, and by far the largest unexploited river in the world. The Mun River tributary is the largest in north-east Thailand, with a catchment of about 70 per cent of the overall north-eastern region.

Historically, the swelling of the Mekong tributaries signalled the end of the difficult dry season and the return to drought-stricken eastern Thailand of more plentiful times -- water for rice paddies, bathing, celebrations, and an abundance of fish and other aquatic life. Damming its waters for irrigation and power generation has been considered by some to be key to Thai development.

"Like all our case studies, the Pak Mun experience will illustrate the challenges in getting development right,"said the WCD Chair, Professor Kader Asmal, who is also South Africa's Minister for Water Affairs and Forestry.

EGAT, Thailand's national electrical utility, commissioned the Pak Mun dam in 1994. Relative to the other WCD case studies, it is a newer and smaller dam (17 meters high, 60-square-kilometre reservoir, installed generating capacity of 136 megawatts and potential to irrigate 25,000 hectares). Pak Mun is unique among the case studies in that it is a 'run-of-river' dam. The WCD study will analyse the evidence about this type of construction which, according to its proponents, does not alter the river significantly.

Pak Mun incorporated some of the 'lessons learned' in constructing dams in earlier decades and its social and environmental mitigation measures accounted for one-third of total project cost. For example, the number of people displaced by the dam was forecast as 20,000 but due to external pressure and the need to preserve river-based tourist attractions, the project was reduced in size and so were the numbers displaced, to 1500. The study will include comparison with, among others, the adjacent Sirindhorn dam, built 27 years ago. Pak Mun's builders offered a more comprehensive resettlement program for those displaced by the reservoir and dam, including compensation that encouraged dam-affected people in the Sirindhorn area to seek retroactive compensation.

The effect of the dam on fisheries is one of the most contested issues and the case study will examine fish biodiversity, food security and income generation from fisheries. The impact of EGAT's fish hatchery in the reservoir and its fish ladders, devised to let fish pass over the dams, will be analysed.

"We're grateful for the support given to this case study by EGAT, academics as well as by non-governmental organisations and affected peoples groups" said WCD Secretary-General Achim Steiner. " In order to help us focus this study, and to encourage a sense of ownership of the WCD's work, both the NGOs and EGAT worked with us in establishing the study's parameters. We look forward to ongoing co-operation from all parties to the debate over dams in Thailand."

Parties involved in the Mekong/Mun River Basin who wish to make submissions on this case study should visit the WCD Website at www.dams.org, call the WCD in Cape Town at Tel 27 21 426 4000 fax 426 0036 or write the WCD at PO Box 16002, Vlaeberg, Cape Town 8018, South Africa.