For thousands of years the mighty Mekong River Basin has served as a life-sustaining force, supporting the livelihoods and food security of more than 40 million people in the region.
The river’s rich mosaic of ecosystems supports the world’s largest inland fisheries and exceptional riverine biodiversity that is only surpassed by the Amazon River. The Mekong provides ecosystem services on a scale so vast that it’s often called the mother of all rivers.
Seasonal ebbs and flows and ecosystem connectivity are the keys to the river’s ecological riches. Its fisheries and other natural resources depend on a complex sediment and nutrient balance, as does the sustainable production of food crops on its fertile floodplains.
Deeply embedded in the region’s economies, culture, history and livelihoods, the river originates in China and flowing through Burma, Laos, Thailand, Cambodia and Vietnam before entering the South China Sea. The river’s astonishing fishery, estimated at 2,500,000 tons of fish per year, is integral to the life throughout the basin.
Yet, despite the vital importance of a healthy Mekong for present and future generations, the river is potentially reaching a tipping point. A dam-building rush on the mainstem Mekong and its tributaries threatens the ecological integrity of the entire basin, and would irreversibly change the river’s hydrology and block the major fish migrations that feed and provide income to millions of people, while also disrupting other vital ecosystem services.
A 2010 Strategic Environmental Assessment commissioned by the Mekong River Commission, the intergovernmental institution charged with sustainably managing the river, warned that a proposed cascade of 11 mainstem dams planned for Laos and Cambodia would irreversibly undermine the ecology of the Mekong River and place at risk the livelihoods and food security of millions of people who depend upon the river’s resources. The report stated that the river’s flood pulse and natural hydrology would no longer be maintained, and that more than half of the river would be transformed into a series of stagnant reservoirs, and its landscape changed forever. Many of the river’s surrounding key biodiversity zones would be inundated. The dams would block vital fish migration routes, reduce vital wetland areas and change the habitat necessary for Mekong fisheries. As a result, more than 100 fish species would be at risk of extinction, including the Giant Mekong Catfish and Irrawaddy Dolphin. Fish catches would drop by as much as 42%. The livelihoods and food security of nearly 30 million people who depend on the river’s rich fisheries would be undermined.
Many of the risks associated with the dams cannot be mitigated and would result in massive losses of economic, social and environmental assets. Given the severity of these risks, the report’s main recommendation was to defer all decisions over whether or not to build the mainstem dams for ten years, to allow for more informed decision-making based on a comprehensive understanding of the risks involved.
Laos dives into dam-building
Despite these significant warnings, the first dam in the cascade of mainstem projects, the Xayaburi Dam, is recklessly moving ahead in Northern Laos. With no transboundary environmental impact assessment, no cumulative impact assessment and no public disclosure of the dam’s final design, the extent of the impacts on neighboring countries remains unclear, while the proposed mitigation measures, such as fish ladders, remain unproven and unlikely to work in the Mekong River.
The Cambodian and Vietnamese governments have repeatedly demanded further study and consultation on Xayaburi. Civil society groups and international governments have echoed their call for construction to stop and respect for international laws, such as the 1995 Mekong Agreement. These calls have led to numerous construction delays, achieved broad international awareness and opposition to the project, and forced the Lao government to commit more than $100 million to improved mitigation measures. A lawsuit against five Thailand government agencies for agreeing to purchase the dam’s electricity is also under review by the country’s Administrative Court.