World Rainforest Movement

Dams on the Mekong mainstream would destroy fisheries for millions

“The Mekong matters to the people who live round it perhaps more than any other river on earth,” wrote Fred Pearce in his book about the world’s rivers, “When the Rivers Run Dry”. Something like two million tons of fish are caught in the Mekong River each year, second only to the Amazon. In Cambodia, 70 per cent of villagers’ protein comes from fish. The Mekong is also extremely diverse, with about 1,300 species of fish, again second only to the Amazon.

The Mekong’s flow is the most variable of any major river in the world. During the monsoon, it contains up to 50 times as much water as during the dry season. This variability is crucial for the fisheries in the Mekong. Every year, as the monsoon rains turn the Mekong into a raging torrent, the water in the Tonle Sap tributary in Cambodia reverses flow and floods a vast area, called the Great Lake. The flooded forests are an incredibly productive ecosystem. Billions of fish fry are flushed into the lake to feed on floating vegetation. An enormous fishing industry exists on the Great Lake.

Overfishing is a threat to this fecundity, but the biggest threat is a cascade of dams planned for the mainstream of the river. China has already build several dams on the upper Mekong and more are planned. In recent years, Laos, Thailand and Cambodia have been dusting off plans first dreamed up decades ago for ten dams on the mainstream Mekong.

In February 2008, the Lao government signed a project development agreement with the Mega First Corporation Berhad, a Malaysian engineering company, to build the Don Sahong dam. The dam would block the Hoo Sahong channel “with devastating consequences for fisheries and fishery-based livelihoods locally and throughout the wider Mekong region”, notes a new report by International Rivers about dams in Laos.

Two months before the Don Sahong agreement was signed, more than 200 NGOs from 30 countries (including WRM) wrote to the Mekong River Commission, the inter-governmental body that is supposed to manage development on the river. The NGOs complained that “Despite the serious ecological and economic implications of damming the lower Mekong, the Mekong River Commission has remained notably silent. We find this an extraordinary abdication of responsibility.” In February 2008, the MRC appointed a new chief executive officer, Jeremy Bird, a Chartered Engineer. The MRC’s silence on mainstream dams has now been replaced by open support.

“The dramatic fluctuations in oil and gas prices over the last year and the growing evidence of change in the planet’s climate have focused global attention on the need for sustainable sources of clean energy,” Bird wrote in the Thai newspaper The Nation in September 2008. The Mekong River is “a source of enormous collective energy potential”, Bird wrote. “To date only around 5 per cent of that potential has been realised.”

As Patrick McCully of International Rivers points out, dams are not sources of clean energy. “Dams and reservoirs are major global sources of global warming pollution,” McCully said last year in a presentation at the Commonwealth Club of California. Organic matter rotting in the reservoirs behind dams emits carbon dioxide, methane and nitrous oxide. More emissions come from the huge amount of cement used to construct the dams and from land clearing and road building related to the construction. McCully points out that emissions from dams in the tropics are comparable to, and in some cases far higher than, emissions from an equivalent sized fossil fuel power plant.

In September 2008, the MRC organised a meeting in Vientiane to discuss the proposals to dam the lower Mekong. None of the millions of people who will be affected if the dams are built were invited to the meeting. Bird explained to a journalist from Inter Press Service that he did not see that as a problem. In any case the meeting took place in English and “in an environment that the communities are not familiar with”. Bird added that “What is important for us is to understand the concerns and the problems of those communities and we can do that in a number of ways.”

While Bird acknowledged that “the issue of fish migration has become central to the discussions,” he did not think that this should stop the dam building. According to Bird. “[T]here will be tremendous efforts now targeted towards first of all avoiding those impacts; if that is not possible, to them minimise what they are and to then mitigate to the extent possible.”

The damage caused by blocking the Mekong with concrete and dramatically altering the river’s seasonal flows cannot be mitigated. Justifying building these dams by claiming that they are climate-friendly, as Bird does, is truly “an extraordinary abdication of responsibility”. Already, fisheries in the Mekong have been severely affected by the upstream dams in China. Building dams on the lower Mekong would destroy the fisheries completely. In turn it would condemn millions of people to serious food shortages and increased poverty.

By Chris Lang,