South China Morning Post
May 7, 2001

A swathe of Cambodia, Laos, Vietnam and Thailand is threatened by up to a dozen dams being built on the Mekong River in China’s Yunnan province, according to a report commissioned by the Asian Development Bank.

The study argues that by restraining water and river matter the scheme will harm the Mekong’s complex ecosystems, which sustain millions of people. This is the first time that outside experts have attempted a full analysis of the dams’ impact on the lower Mekong. Even the controversial damming of the Three Gorges on the Yangzte River did not put the environment and living standards of people in other countries at risk.

The draft of the report compiled by the Stockholm Environment Institute predicts that the project will produce a decline in fish stocks and increase flooding.

An informed observer said the issue had not received international attention because many of the affected countries were dominated by China or looked to it for investment.

“China has an infinite capacity to ignore any criticism that it finds inconvenient,” said the observer. “This dam project was conceived before Yunnan even opened its borders [in the mid-1980s] and no real account was taken of the downstream implications.”

There is no scheme to dam the Mekong outside of China, nor is there likely to be. Existing projects in, for example, Laos and Thailand, have proved controversial and even the enthusiasm of big dam backers such as the World Bank is cooling.

Recent studies have shown that the original environmental impact assessments for the World Bank-backed Pak Moon dam in Thailand, completed in the mid-1990s, were wildly optimistic. The dam, on a tributary of the Mekong, has devastated fishing, transport and irrigation in the area.

Big hydroelectric dams in Laos have also been criticised for destroying large areas of land and hundreds of villages.

Critics of the dams complain that when their true cost is added up they often do not make economic sense.

The Mekong is silty, which often causes dams to be shut down far short of their projected lifespan.

The 1,500-megawatt Manwan dam near the Yunnan city of Dali started operating in 1996. Two more are likely to begin generating power within a few years. But it is the massive Xiaowan dam that causes most concern. As one of two projected “mother dams” in the system, it is so big that the water trapped behind it would reach back 169km. It is scheduled to go into operation within a decade.

China has only recently tried to study the impact its dams are likely to have downstream – after the first dam went into operation.

Chinese officials have claimed that the dam system will benefit everybody because it will “even out” the seasonal water flow. Water would be freed during the dry season and retained during floods.

Environmentalists dispute Chinese claims that only 16 per cent of the Mekong’s waters come out of Yunnan, saying that as far downstream as the Laotian capital, Vientiane, 60 per cent of the river consists of water from China. Officials in Laos claim dry season water levels have hit record lows and fishermen on the river have reported lower catches. There is also scepticism over whether China would adjust the flow for countries downstream if it faced drought or flooding in Yunnan.

Witoon Permpongsacharoen, director of the Bangkok-based environmental lobby group Terra, said recently: “This is the lifeblood, the life source, for millions of people. You simply cannot afford to make any big mistakes with the Mekong.”