Mekong dam plans threatening the natural order

The Australian 29 June 2011 

By Milton Osborne

UNLIKE the Three Gorges dam on the Yangtze, dams on the Mekong River seldom attract Australian attention. Yet a planned dam at Xayaburi on the Mekong in Laos has become central to a debate about the river's future, while the dams China has already built on its section of the river are a subject of long-standing controversy.

Matters have not yet reached the point captured in Mark Twain's quip that "whiskey is for drinking, water is for fighting over," but disagreements among the six countries through which the Mekong flows - China, Burma, Laos, Thailand, Cambodia and Vietnam - have become sharp and could become sharper.

With the exception of Burma, each state has its own view of how the Mekong can be exploited.

Since the 1980s, China has brought four hydro-electric dams on its section of the Mekong into commission, is currently building another and has plans to construct at least three more by 2030. One of the operational dams at Xiaowan is the second-biggest constructed in China and it, with the other completed dams, will soon be able to alter the flow of the Mekong, reducing floods downstream in the wet seasons and preventing the river from falling too sharply in the dry.

These seem desirable developments, but this is misleading. Floods play a positive role, particularly in spreading sediment over the downstream agricultural areas, most notably in Vietnam's Mekong Delta. Altering the Mekong's flow will negatively affect fish catches since fish spawning is linked to existing pattern of flood and retreat.

Though it may be some years before the full effects of China's dams are apparent, there is no doubt many will be negative. But dams below China would, if built, have an almost immediate and dangerous effect in a region that is home to 60 million people in the Lower Mekong Basin.

As early as the 1950s, there were plans to build dams on the Mekong in Laos and Cambodia, but none came to fruition. Now, with commercial backing, proposals exist for no fewer than 11 hydro-electric dams - nine in Laos and two in Cambodia. Dams in Laos and Cambodia could export hydro-electric power to earn foreign exchange as well as extend electricity coverage throughout their own territory, but two major problems would result from these dams. In both countries, fish are a staple of the diet, with no less than 80 per cent of the Cambodian population's annual protein intake coming from fish caught in the Mekong River system.

Dams would block the large-scale migration of fish in the river, an essential part of their life cycle, for there is unanimity among scientists that there are no ways to mitigate the barriers to migration formed by the dams.

Fish catches would be devastated and there is no alternative protein sources to replace them.

The other major drawback that would follow the construction of dams in Laos and Cambodia is the fact they would restrict the flow of water over agricultural areas linked to the river, particularly in Vietnam's rich Mekong Delta. This is an area already under threat from saltwater intrusion and predicted sea-level rises.

These negative judgments about possible dams on the Mekong have been known for many years and were highlighted in a major environmental assessment released by the Mekong River Commission last year.

Yet in the face of scientific evidence and opposition from NGOs, civil society groups and academics, the Laos government appeared determined to build a dam at Xayaburi and announced its intention to do so last year. To its undoubted surprise, the government in Vientiane found that both Cambodia and its long-time ally, Vietnam, were opposed to its plan, both making their opposition clear at a meeting about the dam in Phnom Penh in April.

Following the meeting, it appeared construction of the Xayaburi dam had been put on hold until October, but now it seems the Laos government has opted to proceed with the dam in defiance of its neighbours.

If so, Laos has not only elected to disregard the views of Vietnam, it also makes the possibility of its actions leading to the construction of other dams on the river below China more likely.

The future scenario is of the Mekong ceasing to be a bounteous source of fish and guarantor of agricultural richness, with the great river below China becoming little more than a series of unproductive lakes.

Milton Osborne is a Visiting Fellow at the Lowy Institute for International Policy who has written widely on the Mekong