Water management for the Mekong basin


SINGAPORE — China says it remains a developing country despite its rapid rise in the league of global power. By some measures, it is now the world’s third-biggest economy and second-largest exporter. However gauged, China is clearly a nation with increasing impact and influence, especially if you live in nearby Southeast Asia.

So it comes as no surprise that China is blamed these days for local troubles almost as much as the United States, which Beijing says it will never emulate. The latest finger-pointing at China comes in the wake of devastating floods in parts of northern Thailand and Laos after the Mekong, Southeast Asia’s largest river, overflowed its banks, inundating villages and rice fields and leaving a swath of destruction that will cost many millions of dollars to repair.

The water level Aug. 15 at Vientiane, the capital of Laos on the banks of the Mekong, was the highest since records began in 1913. Although it has dropped since then, low-lying regions in Cambodia and the Mekong Delta of southern Vietnam are bracing for similar damage as the floodwaters move downstream.

Some Thais hit by the floods and nongovernment organizations campaigning against dam building say that water released from the reservoirs of three big Chinese dams on the upper Mekong swelled the runoff from a tropical storm and heavy monsoon rain across northern Laos and China’s southern Yunnan Province early last month.

But the Mekong River Commission, in a statement on Aug. 25, pointed out that the volume of releasable water held by the three Chinese hydro-power dams to generate electricity was too small to have been a significant factor in the flooding. The MRC, established by the governments of Cambodia, Laos, Thailand and Vietnam in 1995, at the end of a long period of conflict in the region, helps to coordinate management of the Mekong basin in Southeast Asia.

As the world’s 12th-longest river, the Mekong runs through or between six countries — China, Myanmar and the four MRC member states. Although the Mekong starts high in China’s Qinghai-Tibetan plateau and flows through China for more than one-third of its total length of over 4,300 km, China is not an MRC member. Nor is reclusive Myanmar. They are “dialogue partners” who meet MRC members from time to time and share only some information about their respective sections of the river.

The MRC says the combined storage capacity of the three Chinese dams on the upper section of the Mekong is less than 1 cubic kilometer. It adds that only a small part of this could have been released as the floodwaters in the area accumulated between Aug. 8, when the tropical storm struck, and Aug. 12, when the flood peak in the Mekong was measured at Chiang Saen, Thailand, where the MRC has its most northerly monitoring station.

At Chiang Saen on that day, measurements showed an accumulated flood runoff volume for the month of 8.5 cubic km, while further downstream at Vientiane on Aug. 12, it was 23 cubic km, leading the MRC to conclude that any release from the Chinese dams “could not have been a significant factor in this natural flood event.”

While that may be true, Chinese dam construction on the upper reaches of the Mekong is a legitimate source of concern for downstream Southeast Asian countries. To generate electricity, water has to be released to drive the turbines. Their worry is that too much will be released in the wet season, contributing to flooding, and too little in the dry season, when the water is needed in Southeast Asia.

This concern will be accentuated when China completes the fourth dam on its section of the Mekong by 2013. The dam at Xiaowan will be 292 meters high, one of the world’s tallest, generating over 4,000 megawatts of electricity, the equivalent output of at least four nuclear power stations. Chinese officials say its 190-square-km reservoir will hold 15 billion cubic meters of water, nearly five times the volume held by the three existing dams. They say this will reduce the amount of water flowing into Southeast Asia by 17 percent during the flood season and increase the flow by 40 percent in the dry season.

Four more dams are planned for the Mekong in Yunnan, one of which will have a storage capacity similar to Xiaowan. Just filling the Xiaowan dam’s reservoir is expected to take between five and 10 years, using half the upper Mekong’s flow. Clearly, a cascade of dams on this scale will affect the amount and quality of water available to downstream states in Southeast Asia.

Averaged over the year, only about 20 percent of the water flowing into the lower section of the Mekong comes from China. However, Chinese policy is particularly important in the dry season, when the long stretch of the Mekong on its territory accounts for 50-70 percent of the water flow at the mouth of river in Vietnam where it meets the South China Sea.

If China is serious when it promises a cooperative and mutually beneficial partnership with Southeast Asia, it should join the Mekong River Commission as a full member, share all hydrologic information with its neighbors and integrate its Yunnan dam planning into the development blueprint for the lower Mekong basin. This would strengthen MRC efforts to develop and apply an integrated management plan for all of the Mekong River basin, with multilateral as well as national interests in mind.

Michael Richardson, a former Asia editor of the International Herald Tribune, is an energy and security specialist at the Institute of South East Asian Studies in Singapore.