Laos Xayaburi Dam would threaten fertility of Lower Mekong Basin

Mekong Delta fertility at risk, experts warn, as they reiterate calls to cancel plans to build the Xayaburi Dam in Laos

Thanh Nien | 4/15/2011

With less than a week to go before the Mekong River Commission’s Joint Committee makes a decision on a major hydropower dam on the river, environmentalists highlighted its infeasibility and called for its cancellation.

If built, the dam could perpetrate an ecological catastrophe, they said.

“Disruptions to fish migration and food supplies for millions in the Mekong basin are likely if the first mainstream dam on the lower Mekong is allowed to go ahead,” the WWF, one of the world’s largest independent conservation organizations, said in a statement released Thursday (April 14).

Expert analysis showed that the feasibility study and environmental impact assessment prepared for the Xayaburi hydropower dam in Laos failed to address key environmental risks, the WWF said.

The US$3.5 billion dam, to be built in northern Laos, would generate power mostly for sale to Thailand.

The Mekong River Commission (MRC), which serves as an international advisory body set up in 1995 by the governments of Cambodia, Laos, Thailand and Vietnam, will meet in Vientiane from April 19 to 22 to reach a conclusion to the regional decision-making process, in which the four member governments are expected to make a decision over whether or not to build the proposed Xayaburi Dam on the Mekong River.

Environmentalists say the dam would disrupt fish migrations, block nutrients downstream and even damage Vietnam’s rice basket by slowing the river’s flow, which sets off severe seawater intrusions into the Mekong Delta.

The plan for the first dam on the downstream region of the Mekong River that flows through the lowlands of Myanmar, Laos, Thailand, Cambodia and Vietnam has been controversial from the outset, with experts saying it could exacerbate impacts already caused by upstream dams built by China.

Environmental advocates have warned that the Xayaburi dam could open the way for 10 more dams being considered along the lower Mekong.

Through public consultation meetings organized by the MRC in January and February, government officials, academics and civil society in Thailand, Vietnam and Cambodia have consistently expressed concern over the dam’s impacts and the need for further studies to be done, she added.

In a WWF commissioned review – coordinated by the WorldFish Center with participation from the United Nations Food and Agriculture Organization (FAO)  – researchers found that the Environmental Impact Assessment (EIA) for the proposed Xayaburi dam in Laos was “woefully inadequate and fell well below international standards” for such studies.

The review found that the EIA ignored published studies and relied heavily on “a very light field sampling” that captured less than a third of the biodiversity in the impact area.

Just five migratory species from a list compiled in 1994 were mentioned and just three of more than 28 studies of Mekong fish migration were referenced. In contrast, current studies show that 229 fish species exploit habitats upstream of the dam site for spawning or dry season refuges, with 70 classified as migratory, according to the review.

According to the WWF, among the species threatened is the Mekong’s famed giant catfish with only known spawning areas in the upper Mekong between Chiang Rai Province (Thailand) and Bokeo (Laos).

“How can you devise mitigation measures for fish passage without addressing the biology and the needs of target species, which in this case range from a small Siamese Mud Carp or Pa Soi to a 3-meter long giant catfish,” asked Jian-hua Meng, WWF International Sustainable Hydropower Specialist, in the Thursday statement.

“WWF supports a 10-year delay in the approval of lower Mekong mainstream dams, including the Xayaburi hydropower dam, to ensure a comprehensive understanding of all the impacts of their construction and operation,” it said.