Mekong flood woes in South-east Asia

China's dams a cause for concern
Michael Richardson, Straits Times 28 Aug 08;

CHINA says it remains a developing country despite its impressively 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 power and influence, especially if you live in nearby South-east Asia.

So it comes as no surprise that China is blamed these days for local troubles almost as ritualistically as the United States is, the superpower 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. The Mekong, South-east Asia's largest river, overflowed its banks, inundating villages and rice fields, and leaving a swathe of destruction that will cost many millions of dollars to repair.

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

Some Thais hit by the floods, as well as non-governmental organisations campaigning against dam building, point the finger at China. The water released from the reservoirs of three big Chinese dams on the upper reaches of the Mekong, they say, swelled the run-off from a tropical storm and heavy monsoon rain across northern Laos and China's southern Yunnan province earlier this month.

But the Mekong River Commission (MRC), in a statement on Monday, pointed out that the volume of releasable water held by the three Chinese hydropower 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 South-east 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 4,300km, China is not an MRC member. Nor is reclusive Myanmar.

The MRC said that the combined storage capacity of the three Chinese dams along the upper section of the Mekong is less than one cubic km. It added that only a small part of this could have been released as the flood waters 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, in Thailand, where the MRC has its most northerly monitoring station.

At Chiang Saen on that day, measurements showed an accumulated flood run-off volume for the month of 8.5 cubic km. Further downstream at Vientiane on Aug12, it was 23 cubic km. This led the MRC to conclude that any release from the Chinese dams 'could not have been a significant factor in this natural flood event'.

While this may be true, Chinese dam construction on the upper reaches of the Mekong is a legitimate source of concern for downstream South-east 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 South-east Asia.

This concern will be accentuated when China completes the fourth dam on its section of the Mekong by 2013. This dam in Xiaowan, at 292m high, will be one of the world's tallest. It will generate over 4,000MW of electricity, the equivalent output of at least four nuclear power stations.

Its reservoir will impound water in a 190 sq km reservoir that Chinese officials say will hold 15 billion cubic m of water, nearly five times the volume held by the three existing dams.

The officials claim that the way they manage and release water from Xiaowan will benefit downstream countries. They say they will reduce the amount of water flowing into South-east Asia by 17 per cent during the flood season and increase the flow by 40 per cent in the dry season.

Four more dams are planned along the Mekong in Yunnan, one of which will have a storage capacity similar to Xiaowan's. It is estimated that just filling the Xiaowan dam's reservoir will 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 South-east Asia.

Averaged over the year, only about 20 per cent 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 per cent of the water flow at the mouth of the river in Vietnam, where it meets the South China Sea.

The four member states of the MRC will meet China and Myanmar in Vientiane tomorrow. The two non-members have the status of dialogue partners. If China is serious when it promises a cooperative and mutually beneficial partnership with South-east Asia, it should join the MRC as a full member, share all hydrological information with its neighbours and integrate its Yunnan dam planning into the development blueprint for the lower Mekong basin.

This would strengthen the MRC's efforts to develop and apply an integrated management plan for the whole of the Mekong River basin, with multilateral as well as national interests in mind.

The writer is an energy and security specialist at the Institute of Southeast Asian Studies.