Construction of the controversial Xayaburi dam could create a “domino effect” of a slew of potentially environmentally-threatening dams emerging on the Mekong River, posing a risk to the Southeast Asian region, experts say.
A Thai construction company’s announcement this week that it would proceed with the construction of the Xayaburi dam in northern Laos in defiance of a consensus among lower-riparian states also sounds the death knell for the Mekong River Commission, a regional inter-governmental body that manages development along the regional artery, the experts warned.
The Xayaburi hydropower project would be the first of 12 proposed dams on the mainstream part of the Lower Mekong.
“If Xayaburi goes forward, all the other dams could go forward,” said Kirk Herbertson from International Rivers, an NGO that works to protect rivers around the world.
Plans to construct the Xayaburi dam, which will generate electricity for Thailand, were shelved in December after a meeting by the Mekong River Commission (MRC), comprising Laos, Cambodia, Thailand, and Vietnam.
Laos’s three downstream neighbors pushed for a suspension of construction following a campaign by environmental groups and local civil society and the recommendation by an expert study group for a 10-year moratorium on all mainstream dams, pending additional research on their potentially catastrophic environmental and socioeconomic impact.
The four countries agreed in principle that further studies on the Xayaburi dam’s impact were needed before it could be built.
Despite that, preliminary construction on the dam has continued, and in apparent further defiance, Thai company Ch. Karnchang signed a U.S. $1.7 billion agreement Tuesday with a Lao power company for the building of the dam.
The MRC is the main body through which the countries negotiate and discuss transboundary effects of management of their shared river and has been important to building consensus in the region.
But if Xayaburi moves forward, it could spell the end of the MRC, said Richard Cronin, an expert on the Mekong region at the Stimson Center, a U.S.-based think tank.
If Laos and Thailand allow the project to continue without MRC consensus, it would likely render the MRC “irrelevant” as an institution, he said.
“There are two ways it would play if Xayaburi were built. One is that it would be the end of the MRC,” he said.
The other possibility is that the regional governments would draw a distinction between dams on the upper part of the Lower Mekong, where Xayaburi is, and dams further downriver that could have an even greater impact on fisheries, he said.
In that scenario, Laos would build “one or two more dams” on the northern part of the Lower Mekong, while other dams would be avoided.
But he noted that it is not yet definite that Xayaburi will indeed be built.
It could be derailed if a new environmental assessment considered the full cost of the dam, unlike previous assessments that were inadequate, Cronin said.
The Mekong River is central to the livelihoods and food security of an estimated 65 million people in the lower half of the river in Cambodia, Laos, Thailand, and Vietnam, studies have shown.
In December, when postponing the Xayaburi project, the MRC agreed to approach Japan to conduct a new study of the environmental impacts.
But Laos and Thailand have so far withheld funds for the new assessment, an issue which MRC country leaders are expected to discuss at a summit in Japan this weekend.
Environmental impact
Whether or not the Xayaburi dam sets a standard for regional cooperation through the MRC to prevent a slew of dams being built on the Mekong, it still has a dramatic environmental impact on its own, experts say.
“It’s not simply a matter of setting a precedent [with Xayaburi]. The environmental impacts would be significant,” said Blake Ratner, an environmental sociologist with the Malaysia-based WorldFish Center.
The most significant impact is that the Xayaburi dam by itself, as the first on the mainstream part of the lower Mekong, would create an immediate block to fish migration.
“While there are some things that change gradually, like water flows or sedimentation, there are other things like blockage to fish migration that are not cumulative,” Ratner said.
“When you put a dam in place, if it crosses the main stream, that’s it. The fish cannot migrate from below or above. They can’t cross that point anymore, he said. “This can already have a dramatic effect, with just one dam.”
Around 1,000 species of fish migrate along the Mekong and tens of millions of people in the region rely on fish for food.
Blocking the fish migration with a dam like Xayaburi could jeopardize not only the patterns of fish migration, but also the region’s food security.
The Xayaburi dam would “directly affect over 200,000 people,” and could wreak “huge devastation on people’s access to food,” Herbertson said.
Tributary dams
But aside from the precedent that Xayaburi could set for large dams—seven more by Laos and five by Cambodia— across the main trunk of the Mekong River, experts are concerned about the slew of smaller dams proposed on the river’s tributaries.
Over 78 dams have been planned or are under construction on tributaries that flow into the Mekong, particularly in the “3S” river region – home of the Sesan, Srepok, and Sekong rivers at the intersection of Cambodia, Laos, and Vietnam.
“While the impact of the mainstream dams is very clear as a block to fish migration, the impact of the dams under construction and planned on the tributaries is no small matter,” Ratner said.
A recent study from the U.S.’s National Academy of Sciences has said that the tributary dams would have “catastrophic impacts” on fish productivity and biodiversity, even greater than that of the mainstream dams.
“The construction of all planned tributary dams would have greater impacts than the combined impact of the upper mainstream dams, including Xayaburi,” it said.
International attention has focused on the mainstream dams, which are subject to international cooperation. The dams on tributary rivers, on the other hand, are not part of the regional process.
“The MRC does not have any authority over tributary dams,” Cronin said.
Overall, the effect of the mainstream and tributary dams combined could threaten “not only food security and livelihoods … but also regional relationships and … regional peace and security, he said.
Reported by Rachel Vandenbrink.