A meeting between the four member states of the Mekong River Commission (MRC) over the controversial Don Sahong hydropower dam yielded no consensus yesterday, meaning that Cambodia, Thailand and Vietnam will have to take their misgivings over the Lao project to the commission’s highest body.

All three neighbouring countries have asserted that Laos is obliged under MRC regulations to submit to a round of prior consultation and allow technical assessments of the dam’s impact due to the fact that the dam is situated on the Mekong’s mainstream – a contention that Laos continued to deny yesterday, according to an MRC statement released after the meeting.

“At the meeting, Cambodia, Thailand and Viet Nam insisted that the project should undergo the Prior Consultation process. They raised particular concerns on the project’s potential impacts on fish migration routes as the Hou Sahong has been the major migration channel for fish to migrate in the dry season,” the statement reads. “Lao PDR clarified that two channels adjacent to the Hou Sahong, Hou Sadam and Hou Xangphuaek, can be used as alternative fish migration routes.”

However, Cambodian delegation leader Te Navuth was quoted as saying if those alternative routes don’t work, “the dam will have impacts on food security and nutrition in Cambodia”.

Due to the lack of agreement, the matter of whether the dam falls on the Mekong mainstream – and therefore requires prior consultation – will now go before the MRC Council, which is comprised of the water and environment ministers of the member countries. But despite being the MRC’s highest governance body, the Council has no legal authority to compel Laos to halt the dam and consent to consultation, said MRC Secretariat communications officer Surasak Glahan.

“If they still have divergent views [after the Council meeting], they can still ask the governments of the four countries to consider the issue,” Surasak said via email. “If this cannot be resolved at the government level, they can seek international arbitration (but this has never happened).”

Though the dam’s proposed site is located in an area where the Mekong’s stream is split into channels by dozens of islands, “there’s no question that this is the mainstream Mekong,” said Ame Trandem, Southeast Asia program director of NGO International Rivers.

“If Laos wants to act in good faith, it should go through prior consultation,” she said.

“This channel is the most important channel in that area for fish migrations,” Trandem said.