By: Our Correspondent

Two crucial decisions face authorities this week on the Mekong River, one of the world’s greatest waterways and the primary source of fish for 60 million people. The Mekong, the world’s greatest fishery, is under growing threat from a wide variety of sources as riparian countries, particularly China build more and more dams on its tributaries. 

Despite efforts to stop them, environmentalists warn, the most immediate threat is two hydroelectric dams being built in southern Laos on tributaries of the river, endangering fish populations, interfering with the river’s natural flood-drought cycle and blocking the transport of sediment downstream, which affects ecosystems along the length of the river.

The Supreme Administrative Court of Thailand is scheduled tomorrow to decide whether to accept a lawsuit against five government bodies, including the Electricity Generating Authority of Thailand who have agreed to purchase 95 percent of the power from the Xayaburi Dam, now about 30 percent completed in southern Laos. And, on Thursday, a Mekong River Commission Council meeting is to be held in Bangkok to call for immediate action to stop the two dams.

“It is once again reckoning day for the future of the Mekong River, however this time around there can be no confusion as to the position of Vietnam, Cambodia and Thailand. Laos must recognize and accept that the Mekong is a shared river, and decisions must be made jointly among Lower Mekong countries, to preserve the future of this irreplaceable resource,” said Pianporn Deetes, Thailand Campaign Coordinator for International Rivers, in a prepared release.

But the river is under threat from far more than the two dams. China has already built seven megadams on the upper reaches of the Mekong, called the Lancang in China, with another 20 planned or under construction in Yunnan, Tibet and Qinghai, according to the Berkeley, Calif.-based NGO International Rivers. The Chinese have never consulted the downstream countries on the construction of their string of dams.

“There is a significant knowledge gap about what is being built,” said the Bangkok-based Ame Trandem, Southeast Asia Program Director for International Rivers. “China agreed to build without consultation with any of the countries. It wasn’t until they noticed changes in the water levels when China built the Xiaowan Dam on the Mekong.”

The Xiaowan, one of the world’s tallest dams, was built in Yunnan. “A lot of information has never been released to the public.” Trandem said.

Even the Mekong River Commission, which came into being in 1995 to try to regulate transboundary construction on the river, has only been told about two of the dams built by the Chinese.

China, as Trandem pointed out, has huge energy needs to fill and a driving need to do it with renewable energy, given that coal-fired powerplants have caused almost unbelievable air pollution in the country. But, she said, China is beginning to understand some of the impact of large dams, especially given the well-publicized environmental problems with the Three Gorges Dam on the Yangtze River.

The two Laotian dams, however, pose the most immediate threat to the river. The governments of Vietnam and Cambodia have called on Laos to halt all construction of dams on the Mekong mainstream for a 10 year period until further studies – including the Mekong Delta study and MRC Council study – are completed. The Laotians say they will take care of the threat to the river‘s fishery via fish ladders and fish elevators, but critics say the technology the Laotians are planning to use is untried, and that fish ladders and elevators don’t really work.  There is also the question of stopping sediment from flowing downstream. Sediment for centuries has renewed precious nutrients for the basin’s rice farmers.

The requests to halt construction while the problems are being studied have gone unheeded by Laos.  Work is continuing on the Don Sahong Dam in southern Laos has continued despite opposition from neighboring governments and ongoing calls for regional consultation. The same situation has characterized the Xayaburi Dam, also in southern Laos, with construction work taking place before neighboring countries have had a chance to try to meet to stop them.

Dam construction is allowed on tributaries to the Mekong under the Mekong Committee’s rules. Laos contends the Don Sahong is on a tributary but the committee and environmentalists contend the dam actually is on the main river.

“Laos remains unwilling to respect the requests of neighboring countries for construction to halt while transboundary impact studies and further consultation can be carried out,” Deetes said.