Cambodia, Vietnam and Thailand have all called on Laos to submit its planned Don Sahong hydropower dam to an intergovernmental assessment.

According to the dam’s opponents, the Laos National Mekong Committee has acted unilaterally in the planning of its second Mekong dam, a project they fear could irreparably damage the region’s food security and biodiversity.

The Cambodia, Vietnam and Thailand National Mekong Committees have each sent separate letters demanding Laos honour regional cooperation pledged by the countries in the 1995 Mekong Agreement.

“We … suggest that the proposed project needs to be considered under the prior consultation process,” states Vietnam’s letter, the only one of the three to be released publicly.

Under the agreement, regulated by the Mekong River Commission, a dam developer must notify or consult with member countries before building.

“Compared with the notification process, which is just the timely submission of materials with no further discussion, consultation requires notification plus a six-month time frame for each country to conduct studies and share concerns,” said Te Navuth, Cambodian National Mekong Committee secretary-general.

Less than two kilometres north of the Cambodia-Laos border, the 260-megawatt dam would potentially have too high an impact on mainstream fish migration in the dry season to bypass consultation with other affected countries, the downstream officials allege in letters sent to the MRC.

“We need the Don Sahong dam to go through a prior consultation process to ensure the people and affected communities can express their concerns and the environmental issues will be addressed,” said Chhith Sam Ath, director of NGO Forum, a member of the Save the Mekong Coalition.

But even with prior consultation, NGOs and activists worry that the dam will follow in the footsteps of Laos’ 1,285 megawatt Xayaburi dam.

Despite the fact that the Xayaburi prior consultation process concluded with a consensus that more assessment was needed, construction began in November last year.

“Prior consultation is prior – it should be self-explanatory that it means concerns are shared and resolved before any work starts,” Navuth said.