As lower Mekong countries prepare final evaluations of Laos’ contentious Don Sahong dam for a regional assessment next month, Vietnam launched a preemptive broadside at the project this week.

During a conference in Hanoi on Monday, the Vietnamese National Mekong Committee said the 260-megawatt project would block the river’s flow, which in turn would disrupt the passage of migratory fish, damage the local ecological environment and negatively impact the livelihood of locals, according to Vietnamese media.

Committee deputy spokesman Nguyen Hong Phuong put it bluntly: few fish could survive the dam.

At a concurrent meeting also assessing the project’s impacts in Can Tho, waterways experts forecasted a bleak future for the Mekong Delta if the hydropower dam moves ahead.

Due to a change in sediment flow and fish migratory patterns, the dam will deal a blow to lower areas of the river like the Mekong Delta, where farmers could see severe crop damage, Phan Thanh Long, from the Aquaculture Research Institute, reportedly said.

Briefing notes from an ongoing review of the dam by five expert groups preliminarily agreed that more studies are needed.

“At present there is insufficient information to assess whether this is viable,” read the briefing notes, which were presented at a meeting in Laos earlier this month.

The experts allege that the developers of Don Sahong have attempted to design mitigation measures while missing critical information.

“A large fish passage project needs a biological baseline, including the species and sizes of fish,” it reads, while also noting that “insufficient attention has been paid to potential cross border impacts on fisher communities in Cambodia”.

“A lot of the conclusions point to a lack of information and concrete, scientific data,” said Te Navuth, secretary of the Cambodian National Mekong Committee. “If I could, I would make all the [Mekong River Commission] member countries see that there is a need for further study. The project should delay for two to three years at least, until there is a fuller evaluation of the impacts.”

During questioning at the National Assembly yesterday, Minister of Water Resources and Meteorology and head of Cambodia’s committee Lim Kean Hor also reiterated the call for more analysis.

“We Cambodians still demand Laos, as the owner of Don Sahong dam, provide us with the report of evaluating the effects of the dam on us,” he said.

Cambodia’s national committee is set to provide its full conclusions on the dam later this month.

ADDITIONAL REPORTING BY TAING VIDA