The giant of hydropower
The Mekong River begins on the Tibetan Plateau, described as the "Roof of the World". The river runs to the South China Sea, with an estimated length of up to 5000 kilometers.
China is the world's biggest producer of hydropower. Since the 1950s the nation has built over 20 000 large dams, which have accelerated its phenomenal growth into a global economy. China consumes more energy than any other country and is now expanding its energy efforts by investigating still untapped resources in its Southwest regions.
In addition to China, the Mekong River affects over 60 million people living in Myanmar, Laos, Thailand, Cambodia and Vietnam.
The first mainstream dams
The Mekong mainstream stayed in its natural state until China started to build the dam of Manwan. The power station was opened by mid-1990s.
The total power capacity of the Manwan Dam is 1,550 megawatts. (You may compare the capacities of the dams by clicking them on the map.) The biggest hydroelectric dam in the world is China's Three Gorges Dam of Yangtze River with a capacity of 20,300 megawatts.
In the 2000s China continued to build into the Mekong mainstream. The Nuozhadu and Xiaowan, which were both constructed during this time, remain among the country's biggest dams. Now China has plans for even 14 new dams for Mekong upstream, of which at least four are under construction: Wunonglong, Lidi, Huangdeng and Miaowei.
Mekong returns to politics
The tributaries of Mekong have been an important energy resource for the region's countries for decades.
Mainstream dams have been under consideration in Laos and Cambodia since 1960s, but plans were shelved since local and international impacts were too risky.
This was to change as the example set by China was accompanied by the rising oil prices and the growing need of energy by Thailand and Vietnam. As hydropower could also be marketed as a climate-friendly option apart from fossil fuels, the Mekong became again the spearhead of politics.
Commission states drastic changes
The Mekong River Commission is an intergovernmental organization coordinating the water resources of river basin countries, excluding China.
In 2010 the commission released a Strategic Environmental Assessment of the dams planned for the Mekong mainstream. The study recommended that the decisions regarding dam construction should be deferred for ten years in order to further examine their complex impacts.
The study concluded that even one mainstream dam would likely bring irreversible changes to the environment and weaken the livelihoods of the region's poorest communities.
Xayaburi moves forward
In 2012 Laos began the construction of the Xayaburi Dam, despite Cambodia's and Vietnam's strong efforts to delay the project. Xayaburi will be the first mainstream dam in the Mekong downstream.
Among the contractors of the project is a Finnish consulting company Pöyry, responsible for the technical assessment ordered by the Lao government. Non-governmental organizations have criticised Pöyry for dismissing some of the project's implications to nature and human rights.
As the project moved forward, Pöyry made an eight-year contract on consulting the construction project.
Competition for power
Laos is one of the poorest countries in Southeast Asia. The Lao government sees the mainstream dams as a possible means to become a true economic player in the area by exporting electricity. The dams lure foreign investments from China, Thailand and Malaysia.
Thailand, for example, faces a growing demand for energy, but concerning dams it has greater inner-political challenges. For China the dam investments are part of securing its economic and political power in the area, where alone in Laos it has over 5 billion dollars in cumulative investment.
Cambodia and Vietnam are estimated to suffer the most negative impacts of mainstream dams.
How much is enough?
The rapid development of the Mekong region calls for more energy. The mainstream dams could cover as much as ten percent of the projected energy demand of Mekong River Commission countries by 2025.
Electricity imports are vital to rapidly-developing Vietnam, though predictions for its future energy needs vary. The Vietnamese government foresees the nation to even overtake Thailand in demand, whereas the Asian Development Bank has presented much smaller figures.
Of all the region's countries, Cambodia has the largest unmet demand for energy, but is also predicted to suffer most from the drastic impacts of the many damming projects.
The mainstream dams are predicted to reduce the water flow to the downstream in the rain season. Growing rice would likely become harder as the nutrient sediment would not flood into the fields as before. The life cycles and reproductive processes of migratory fish would also be affected.
Especially in Cambodia, the diminishing fish stock would impact the livelihoods of the poorest fishing communities. The Mekong River is a critical element for Cambodia's Tonle Sap Lake, which acts as a valve for Mekong’s downstream flow. Tonle Sap is one of the largest freshwater lakes in the world.
The Sambor Dam, presented in several plans, would be Cambodia's biggest dam.
Species under threat
Only the Amazon River beats the Mekong in aquatic biodiversity. It is estimated that the river supports over 1200 fish species, from which over half have been characterized.
Drastic changes to water levels and nutrients would be a threat to several species threatened by extinction. For example, the region of Stung Treng Dam is home to endangered species such as the Irrawaddy dolphin, Mekong giant catfish and Siamese crocodile.
The wetlands also harbor rare birds and mangrove swamps, which serve as a natural protection from erosion.
The world's food market
The sediments of the Mekong are needed in the Vietnam delta, home of 20 million people and fifth of the population of Vietnam.
The delta is one of the most nutrient-rich places in the world, providing rice and seafood which form the backbone of Vietnam's economy. The area's products, such as shrimp and pangasius, are exported around the world.
As the natural flow of the Mekong diminishes, the salt water expands further in the delta. Proper research for the area's future has only just begun.
In fall 2013, Laos announced to the Mekong River Commission that it will begin the construction of the Don Sahong Dam. It will become the second mainstream dam for Laos. According to environmental organizations, the other countries could even seek financial compensation from Laos for this project’s regional effects.
Despite its efforts, the Mekong River Commission has not been able to cancel or delay the construction of mainstream dams. Vietnam has demanded more cooperation and is planning to focus more research on the impacts of hydroelectric dams during 2014.
At the same time, less politically sensitive dam projects in Mekong's tributaries have seen substantial growth. Around 40 dams have been planned, mostly by Vietnam and Laos.
The Mekong is seen as the source of both outstanding natural beauty and economic and political power. The mainstream dams will bring unprecedented changes to both of these sides.