As Laos pushes toward its goal of becoming the “battery of Asia” through hydropower, its newfound claim that the location for the proposed Don Sahong dam is not on the Mekong River’s main stream is provoking incredulity from some observers.

Less than two kilometres north of the Lao-Cambodian border, where the Don Sahong is slated to be built, developers call the Hou Sahong channel a Mekong tributary. Under the 1995 Mekong Agreement, that would require downstream neighbours only be notified – rather than consulted – before construction of a dam.

“But it’s not on a tributary, it’s on a channel in the middle of the Mekong,” said Meach Mean, coordinator of the 3S Rivers Protection Network. “This is the one channel that fish can migrate up year-round to spawn; they cannot swim up the other channels in the dry season.”

According to regulations outlined by the Mekong River Commission, if a dam changes mainstream river flow in the dry season, or diverts water from the mainstream in the rainy season, the country building it must consult with other member states prior to construction.

In 2007, the MRC Secretariat requested that the Don Sahong, as a year-round power generator using mainstream flows, file for prior consultation.

In the June MRC meeting, Australian Ambassador to Cambodia Alison Burrows asked on behalf of development partners including the US, European Union, Japan and the World Bank that the project undergo consultation.

Ignoring these requests, on September 30, Laos submitted a notification to the MRC, along with its intention to pursue construction beginning this month.

“The notification from the Lao government specifies that on average the Hou Sahong channel naturally carries 5 per cent of the total flow of the Mekong water in that area. This could imply that Lao PDR considers that water use on this channel would have limited impact on the water quality or flows regime of the Mekong mainstream,” said Surasak Glahan, MRC Secretariat communications officer.

Last week, US-based NGO Conservation International called for a moratorium on Mekong hydropower projects.

And on Friday, NGOs in Thailand demanded an immediate halt to the dam’s development in a public letter by the Foundation for Ecological Recovery.

“The Don Sahong Dam was registered as one of 12 mainstream dams [in earlier proposals] and all MRC country members were informed of this,” reads the letter. “Engaging the ‘prior notification’ process instead of the ‘prior consultation’ reveals Laos PDR’s action to distort information in order to quicken the construction process.”

Officials at the MRC said they have not taken a position.

“What’s happening with Don Sahong is showing a weakness in the MRC agreement,” said Youk Senglong, from the Fisheries Action Coalition. “There isn’t any sort of regional authority to turn to when countries don’t follow the agreement.”

Dam project managers did not return requests for comment.