National Geographic
Menu

Moratorium Needed on Mekong River Dams

picture of a mekong giant catfish
Three men capture a 591-pound, 5-foot-long Mekong Giant Catfish from the Tonle Sap River in Cambodia. Photograph courtesy of Zeb Hogan

Few development schemes pose more serious risks to food security, fisheries, and aquatic ecosystems than the construction of proposed hydropower dams on the main channel of the Mekong River in Southeast Asia.

Three years ago, in an environmental assessment of those proposed dams, the Mekong River Commission – the body that oversees regional cooperation in the Mekong Basin – recommended that dam construction on the Mekong be halted for ten years to allow time for further study of their impacts and proper consultation among the lower-basin countries – Laos, Thailand, Cambodia and Vietnam.

But with work on the Xayaburi Dam in northern Laos now underway, and the Laotian government’s announcement five weeks ago that it intends to proceed with another dam near the Cambodian border, the time has come for the MRC and the international community to take more assertive action to bring a moratorium into effect.

Hanging in the balance are the livelihoods of millions of people, the continued existence of one of the world’s most productive fisheries, the prospects for equitable and sustainable development in the region, and, quite possibly, regional peace and stability.

The River that Keeps Giving

Rising on the Tibetan Plateau, the Mekong River runs approximately 4,400 kilometers (2,700 miles) through China, Burma, and the four lower-basin countries before emptying into the South China Sea.  More than 60 million people in the lower basin depend on the Mekong for their food security and livelihoods.

The Mekong yields a wild fish catch of some 2.2 million tons a year, providing crucial protein for the region’s inhabitants.  The nutrients the river carries downstream nourish floodplain farms that produce vital crops during the dry season, as well as fertilizing the Mekong Delta, the rice bowl of Vietnam.

Home to at least 500 species of fish – and some estimates run upwards of 1,000 – the Mekong ranks just behind the Amazon in terms of fish diversity.   The critically endangered Mekong giant catfish, one of the largest fish in the world, migrates hundreds of kilometers between its rearing and spawning grounds, which scientists believe to be in Laos and northern Thailand.

Perhaps only a few hundred of these Mekong giants remain.

“We know very little about the ecology of these species and what we do know suggests that they need healthy, free-flowing rivers to survive,” according to Zeb Hogan, a biologist at the University of Nevada and head of National Geographic’s Megafishes Project.

The Mekong also sustains the Tonle Sap, the largest freshwater lake in Southeast Asia and the source of 75 percent of Cambodia’s inland fish production.  Home to more than 200 species of fish, 23 species of snakes, and 13 species of turtles, the Tonle Sap is an ecological hotspot and a designated UN Biosphere Reserve.  Scientists believe the Mekong giant catfish rear primarily in the Tonle Sap.

Weighing the Tradeoffs

With energy demand in the lower Mekong basin expected to triple or quadruple by 2025, there is clearly a need for more power generation capacity in the region.

Eleven hydroelectric dams have been proposed for the lower Mekong – nine in Laos and two in Cambodia.

The first to go under construction is the Xayaburi, and although Laotian officials have variously said that only preparatory work is under way, that work on the dam had been suspended, and that construction will not begin until after consultations with its neighboring countries, visits to the dam site suggest work is indeed under way.

After a trip to the site in June 2012, the non-governmental organization International Rivers posted a series of photographs showing the river being dredged and widened.

Xayaburi is expected to cost $3.5 billion and take eight years to build.  About 95 percent of the power generated by the dam is slated for export to Thailand.  Four Thai banks are financing the project.

“The Xayaburi dam is a dangerous experiment,” Dr. Jian-hua Meng, Sustainable Hydropower Specialist with the World Wildlife Fund (WWF) was quoted as saying in a news release.

“The risk to fisheries, fish migration and impacts from sediment effects are immense, and the consequences for downstream countries dire. There are 11 dams planned on the lower mainstream of the Mekong, and the region can’t afford to get a single one wrong.”

The tragedy is that with more careful study and examination of alternative sites and power sources, much of the damage from Xayaburi and other dams on the Mekong’s main channel might be avoided, while still meeting energy demands.

The Mekong River Commission (MRC) estimates that, if built, the mainstream dams would together meet 6-8 percent of the projected lower Mekong basin power demand in 2025.

“There are locations on the Mekong that are suitable for genuinely sustainable hydropower,” said WWF’s Jian-hua Meng, “but the Lower Mekong countries must urgently get the MRC back on track to broker those negotiations and fill the major science and data gaps, or risk building dams by guesswork.”

In the wake of the September 30th decision by Laos to proceed with the Don Sahong Dam – which will block the only channel available for dry-season fish migrations on the Mekong –WWF has called for an emergency meeting of the MRC.

Time to Act

The Mekong River Commission’s environmental assessment finds that the eleven proposed hydroelectric dams would “fundamentally affect the integrity and the productivity of the Mekong aquatic system,” including a 12-27 percent reduction in primary productivity, a 75 percent reduction in nutrient loading, and the likely extinction of  a number of globally endangered species.

In addition to noting that alternatives to damming the Mekong main channel have not been adequately explored, the MRC assessment finds that the dam projects would likely worsen poverty and inequality in the lower Mekong basin countries, and degrade the livelihoods of the poorest communities along the river.

The MRC assessment recommends that decisions on the mainstream dams be deferred for ten years, with reviews every three years to ensure that the studies and consultations needed to make informed decisions are, in fact, taking place.

With the Xayaburi Dam under way, and the Don Sahong Dam slated to begin soon, the government of Laos is not abiding by the MRC’s process of notification, prior consultation and agreement.

During a visit to Laos in July 2012, then U.S. Secretary of State Hillary Clinton pushed the government to further study the impacts of the Xayaburi Dam on its downstream neighbors before proceeding.

Clearly, more international pressure and stronger action from the MRC are needed.

The full potential of the Mekong can only be realized if the countries joined by the river work collaboratively to maximize and share its full range of benefits for this and future generations.

A moratorium on dam construction of at least a decade is needed to begin and solidify this process.

Sandra Postel is director of the Global Water Policy Project, Freshwater Fellow of the National Geographic Society, and author of several books and numerous articles on global water issues. She is co-creator of Change the Course, the national freshwater conservation and restoration campaign being piloted in the Colorado River Basin.

Comments

  1. Emmeline Johansen
    New Zealand
    November 21, 2013, 4:50 pm

    Conservation International in Cambodia is currently calling for a moratorium on dam development in the 3S Dams – tributaries to the lower Mekong. We have produced a film using new data provided by the University of Canterbury in New Zealand. To watch the film or for more information visit: http://cambodiahydropower.weebly.com/

  2. Robert Rofen
    23059 Avis Lane, Hayward, CA 94541 USA
    November 8, 2013, 2:25 pm

    These are interesting and I would like to receive News Watch, particularly Ocean Views and Water Currents by e-mail. I am a member of the National Geographic Society and receive National Geographic magazine.

    • Sonia Harmon
      November 8, 2013, 5:13 pm

      Hi Robert,
      You cannot receive News Watch posts by email, but you can subscribe to our RSS feed and get updates on when we post new stories here: http://newswatch.nationalgeographic.com/feed/

  3. Danzig Sopera
    Cambodia
    November 8, 2013, 8:57 am

    Just to point out that the MRC never advocated for a 10 year moratorium on dam building on the mainstream. The report which I assume you’re referring to (Strategic Environmental Impact Assessment for Hydropower on the Mekong Mainstream) was written by the International Centre for Environmental Management, and published by the MRC. The report does not represent an MRC ‘position’.

    I’d also like to point out that there’s many studies to suggest that the cumulative impact of tributary dams may very well surpass the impact of the mainstream dams (cf. Ziv, G., Baran, E., Nam, S., Rodríguez-Iturbe, I. and Levin, S.A. 2012. Trading-off Fish Biodiversity, Food Security and Hydropower in the Mekong River Basin. Proceedings of the National Academy of Sciences 109 (15): 5609-5614; and Costanza, R., Kubiszewski, I., Paquet, P., King, J., Halimi, S., Sanguanngoi, H., Bach, N.L., Frankel, R., Ganaseni, J., Intralawan, A. and Morell, D. 2011. Planning approaches for water development in the Lower Mekong Basin. Portland State University and Mae Fa Luang University, July 2011).

    And, finally, when ‘weighing the trade offs, you don’t really talk about the benefits that might accrue to Laos (and, indeed, Cambodia) in terms of revenues that can contribute to national development. These are some of the poorest countries in the world!

    • Sandra Postel
      November 8, 2013, 11:17 am

      Thank you for your comment. I think it adds to the reasons to step back and study the alternatives before decisions are made and irreversible impacts generated. The MRC framework offers sound principles for international water management by riparian countries, but the process must be followed. (I say this knowing full well that in my country we failed to follow a sound process in developing our own dams and rivers, the bi-national Colorado of course being one.) In the Mekong, environmental flow assessments need to be carried out and compared in the context of the proposed alternatives, including both proposed mainstream and tributary dams. Only in this way can the benefits and costs be evaluated in a scientifically sound way. Finally, I couldn’t agree more about the need for poverty alleviation in this region. But the assessment published by the MRC suggests that in the short and medium term, poverty would likely worsen.