From the Lowy Institute's The Interpreter blog:
Beijing’s islands-building in the South China Sea and their militarisation, replete with surface-to-air missiles, is near complete. With guile, threat, and coercion, China can now seize control of one of the main transport arteries of Southeast Asia, making a mockery of international laws and norms.
But there is another prize in Beijing’s sights, an artery that runs straight through mainland Southeast Asia. The mighty Mekong River, which starts in China (known there as Lancang), and connects Myanmar, Thailand, Laos, Vietnam, and Cambodia, is a crucial lifeline that nourishes some 60 million people along its banks.
Control of both the South China Sea and Mekong River will strategically sandwich mainland Southeast Asia. Indeed, Beijing’s control of Southeast Asian rivers looks set to be the other half of its “salami slicing” strategy in the region.
Famine is more terrible than the sword
Controlling the Mekong River’s flow with dams along the waterway ultimately means controlling access to food, and therefore the livelihoods of tens of millions of people in downstream riparian communities. Of the hydroelectricity dams on the Mekong, the vast majority of currently installed capacity (megawatts) is in China, accounting for more than 15,000 MW. This includes a half-dozen mega-dams over 1000 MW, including Nuozhadu dam which churns out 5850 MW.
Together these dams can hold back 23 billion cubic metres of water, or 27% of the river’s annual flow between China and Thailand. Other dams in the lower Mekong are piddling by comparison, with generating capacity in the tens or low hundreds of MW.
The bottom line: Chinese dams can now regulate the Mekong’s flow.
This is even more pronounced in the dry season when the Tibetan Plateau contributes between 40 and 70% of the river’s flow. The impact on food and livelihoods is dramatic now, but could soon be far worse if 11 proposed mega-dams, half with some Chinese involvement, go ahead.
A recent UNESCO and Stockholm Environment Institute report suggests sediment flows in the river could reduce by up to 94% if the proposed dams go ahead, significantly affecting fish catches and overall river health. This will directly affect downstream riparian communities.
More worryingly, the raison d’être of the proposed dams and oft-cited promise of a crucial electricity boost for the economies of the lower Mekong has been found to be misguided. Many of the proposed lower Mekong dams will export their energy to China, and others will have direct negative impacts on the economy. It is projected that over the next 50 years, the cost for the lower Mekong basin economy will be a net negative $7.3 billion, with Vietnam and Cambodia the worst off. The social costs could be just as astronomical.
Dams as dominoes
During a recent trip to Laos, I encountered concerns about Chinese dams being used as strategic levers, producing unannounced upstream releases of water that impact not only communities but also new downstream dams. In such a case, the downstream dams would need to immediately release water through the spillway, at best resulting in the loss of valuable generating capacity, potentially impacting electricity supply, and at worst flooding downstream villages or damaging the integrity of the dam wall.
Already many of the dams on the tributaries of the Mekong are uninformed of upstream releases in the Mekong proper, potentially affecting their own release of water by creating a flood surge when the released waters converge. One of the operators of a joint venture dam in Laos confided that there was often little or no forewarning when water from a Chinese-built upstream dam was released...MORE.