A hydropower dam proposed for Laos’ northern Xayabury province could have serious negative effects on fisheries, biodiversity and livelihoods downstream in Cambodia, a spokesman for the World Wide Fund for Nature has said.

“Cambodia will be one of the hardest hit countries from the construction of any, including Xayabury, of the proposed 11 lower Mekong mainstream dams,” said Marc Goichot, a senior adviser on sustainable infrastructure at WWF Greater Mekong.

“These impacts are potentially catastrophic, and can include riverbank erosion, impacting the riverside homes of millions of Cambodians.”

Laos notified the Mekong River Commission of its plan for the 1,260-megawatt dam on September 22.

Goichot’s assessment was far bleaker than that of Pich Dun, secretary general of the Cambodian National Mekong Committee, who acknowledged that the dam would “affect fish migration, but not very seriously”.

“According to the study, the dam is being built far from Cambodia, so only some kinds of fish are migrating from here to there, and that is why the effects will not be so huge,” Pich Dun said.

“But if all 11 dams are built, the people on the lower Mekong will face difficulties with the change in the flow of sediments to their crops,” he said.

But Goichot said the dam would “lead to the extinction of the Mekong giant catfish in the wild and probably other fish species”.

Sam Nouv, deputy director for the Fisheries Administration, said he, too, was “concerned” about the dam. “When a dam is built on the upstream, it really impacts the fisheries in Cambodia,” he said. ADDITIONAL REPORTING BY SAM RITH