Whether the dams are to blame remains a contested question
China's dam-building spree along the Mekong river in south-western Yunnan province has raised fears among several of its neighbours, who say the dams have led to shrinking levels of water downstream.
Officials from Thailand, Laos, Vietnam and Cambodia, countries which lie in the Mekong basin, will on Sunday voice their concerns over eight dams that China is building along the Mekong, in talks with Chinese officials in Thailand.
The four countries in 1995 set up the Mekong River Commission (MRC) to facilitate joint management and water-sharing in the Mekong region, though China and Myanmar have so far refused to formally join the body. The Mekong runs almost half of its 4,400 km course in China's south-west, where it is known as the Lancang, before entering Myanmar and Laos.
The MRC's concerns closely echo those voiced by India in the past over China's plans to build dams along the Brahmaputra, or the Yarlung Tsangpo as it is known in Tibet. In both cases, China's position as an upper riparian or upstream-lying state has given it an advantage in controlling the rivers' resources, say experts. International laws allow China to build hydropower projects that do not divert or substantially alter the course of the rivers, though the absence of robust water-sharing arrangements has led to persisting concerns in several downstream countries, including India, over the future of their water security.
“We can see the level of the water is getting lower,” said Abhisit Vejjajiva, Prime Minister, of Thailand, last month. “We will ask the Foreign Ministry to talk with a representative from China in terms of co-operation and in terms of management systems in the region.”
An estimated 60 million people depend on the Mekong river in the five countries that lie downstream. China has already built three dams in Yunnan. Five more are in the works, including the massive $4-billion Xiaowan dam, scheduled to open in 2012, which is the world's highest dam.
But whether the dams are behind the Mekong's shrinking levels downstream still remains a much-contested question.
In May, the United Nations Environment Programme warned of a “considerable threat” the dams posed to water management in areas downstream, though China says the course and flow of the Mekong have been unaffected by its projects.
Speaking ahead of Sunday's talks, Chen Mingzhong, deputy Director-General of the Department of International Cooperation at China's Water Resources Ministry, said on Friday the dry weather in the lower Mekong areas was the “root cause” of the reduced run-off water downstream, and that the dams would help, not hinder, water management. Officials say the river's flow in China only accounts for 13.5 per cent of its net flow, according to their data.
The Chinese government views the dams as crucial to maintaining water security in its south-west, which is currently facing its worst drought in five decades, affecting more than 24 million people. The government has allocated 27 billion Yuan ($4 billion) to build more reservoirs and dams in Yunnan alone.
“The hydropower stations built on the Lancang River will not increase the chance of flood and drought disasters in the downstream. Instead, it will considerably enhance the capacity of flood control, drought relief, irrigation and water supply for the downstream countries,” Mr. Chen argued.
But his country's neighbours, however, remain unconvinced.