The Nation 10 December 2010
By Pongphon Sarnsamak
The Mekong River Commission, in its Strategic Environmental Assessment, has urged Thailand, Laos, Cambodia, and Vietnam to delay megahydropower dams for 10 years due to massive risk concerns associated with the projects.
According to Carl Middleton, programme director of the conservation group International Rivers, the report was released in October.
He said it has studied the environmental impact and ecological systems in 12 dams planned for the Mekong River.
It has also consulted government agencies, nongovernmental organisations and the private sector.
The report found that if built, the dams would cause irreversible and permanent ecological change to a mighty river that feeds millions of people.
It said 50 per cent of the length of the Mekong River would become reservoir and the rapid change in river levels would destroy the natural flow of water.
The proposed dams would block a vital fish migration route and damage the habitat and ecosystem of the Mekong, placing at risk its rich diversity of species. Fishery activities would reduce by 26 per cent to 42 per cent of present levels, at a cost of Bt 15 billion.
The report said at least 100 of the river's aquatic animal species – such as the Irrawaddy dolphin and iconic giant catfish – would be at risk of extinction due to severe change in their habitat.
The 12 dams would inundate half the river's bank gardens with damage estimated at Bt630 million a year, affecting over 3 million people along the Mekong.
The report said such mainstream projects were likely to result in serious and irreversible environmental damage, losses in longterm health and productivity of natural systems and losses to biological diversity and ecological integrity.
The largest impact on the riverine terrestrial system would be to the wetlands. Almost 40 per cent lie within reaches of rivers where projects are located – 17 per cent would be permanently inundated by the Lowee Mekong asin mainstream projects.
The report established that 96 per cent of power demand, up to 2025, stems from Thailand and Vietnam. These two countries are expected to purchase close to 90 per cent of the power generated by the mainstream projects.
If Thailand and Vietnam decided not to buy mainstream power, the projects – all designed for export - would likely not go ahead.
According to the report, 10 proposed mainstream projects would involve constructing dams across the entire river channel – eight in Laos, two of which are on the LaoThailand reaches of the mainstream, and two in Cambodia.
Two other projects near the Khone Falls in Laos involve either partial damming (Don Sahong) or a diversion (Thakho). In China's Yunnan province, eight dams spanning the Lancang River already exist, or are under construction.
China's decision to develop the Mekong River in Yunnan - and the resulting changes in seasonal flows - has eased previous reluctance to dambuilding in the Lower Mekong Basin (LMB) and made mainstream projects more economically viable. Other international factors, such as reduced greenhouse gas emissions compared to fossil fuel generation options, and efforts to reduce reliance on imported energy and increase supply diversity, make hydropower an increasingly attractive renewable energy resource for LMB countries.
Xayaburi hydropower dam is the most advanced of the large dams planned for the lower Mekong, Middleton said.
Thailand's Ministry of Energy and electricity utility Egat will play a role in determining whether the Xayaburi dam is built or not.
Middleton said the Mekong River Commission and regional decisionmakers should halt the Xayaburi dam, while adhering to recommendations of the Strategic Environmental Assessment to defer a decision over the Mekong for at least 10 years.
Significant knowledge gaps about the Mekong River, and the regional decisionmaking process, have failed to meet international standards of transparency, public participation and accountability, Middleton said.
Consequently, an informed decision over the fate of the river cannot be made and the region risks jeopardising the very resource that brings benefit to millions of people, he added.