Amid a lawsuit and a chorus of dissent, developers of the first lower Mekong mainstream hydropower project, the massive Xayaburi dam, have quietly submitted a long-anticipated, multimillion-dollar redesign plan, the Post has learned.

What exactly has been changed about the 1,260-megawatt dam, which environmentalists contend will decimate migratory fish populations, remains a mystery, however, as the plan isn’t being shared.

“Laos has sent the redesign documents to the [Mekong River Commission’s] Secretariat only and not to the MRC member countries. Development partners have requested the redesign documents, but they never received them,” said Te Navuth, secretary general of the Cambodian National Mekong Committee.

Navuth added that he has not seen the submitted plans, which, since the dam is already full swing into construction and 40 per cent completed, represent little more than a token gesture.

According to the MRC, an intergovernmental advisory committee, the revised dam plans were submitted in February for an internal assessment.

“The information and our analyses can be shared with the other Member Countries once our analysing work is done,” said Surasak Glahan, MRC secretariat communications officer. “The Lao government made it clear however, that the sharing of information on the modifications is not to seek approval for the redesign, but rather for them to receive input and expert advice on ways to avoid, minimize and mitigate impacts from the project in a practical way.”

Two years ago, the Lao government announced that the $3.8-billion dam project would see an additional $100 million spent to revamp fish passages and sediment flows in line with recommendations from two enlisted foreign consulting firms: Poyry of Finland and the French Compagnie Nationale du Rhone. But by the time the official groundbreaking ceremony rolled around in November 2012, no one had seen the reworked plans.

Though they haven’t seen the new plan, critics contended that any redesign would be invalid, as there isn’t enough data on hydropower’s impact to the shared waterways.

“Without comprehensive assessment and disclosure of all project documents and studies that are underway, no one can say or be confident that the mitigation measures will work, as they have never been tested in this region,” said Pianporn Deetes, a coordinator at International Rivers.