Review of the Pöyry Report on the Xayaburi Dam

Kirk Herbertson

In May 2011, the Lao PDR government hired Swiss engineering company Pöyry Energy AG to review the proposed Xayaburi Dam's compliance with the Mekong River Commission (MRC) requirements for Mainstream Dams. In August 2011, Pöyry submitted its final report to the Lao government, finding the project to be "principally in compliance" with the MRC's requirements. The Lao government has since sent this report to neighboring countries as false justification that it has responded to their concerns about the project.

International Rivers reviewed the Pöyry report and found numerous inconsistencies and scientific shortcomings, which make it an unsuitable basis for decision-making among the MRC member governments.

Key findings include:

  • Failure to respond to other governments' concerns: Pöyry recommends that construction on the Xayaburi Dam should proceed, even though the concerns of other MRC member governments about the transboundary impacts have not been addressed.
  • Failure to meet the MRC's requirements: At least fifteen fundamental MRC Preliminary Design Guidance requirements have still not been met by the Xayaburi Dam project developer, and Pöyry omitted mention of many of these requirements.
  • Mixed messages: Despite finding that the Xayaburi Dam is "principally in compliance" with MRC requirements, Pöyry also recommended conducting over 40 additional studies to bring the project into compliance.
  • Gaps in information: The report admits that numerous gaps remain in understanding about the project's potential impacts, making it impossible to design mitigation measures at this stage. These include gaps in knowledge about impacts on Mekong fish species, people who depend on fisheries for their livelihoods, ecosystems, sediment flows, and dam safety. Despite this, the report recommends trying to fill these gaps during the project construction stage, in violation of MRC guidelines and contrary to established scientific practice.
  • Continued high risk to the Mekong's fisheries: Pöyry claims that the dam's impacts on Mekong River Basin fisheries can be mitigated using fish passage technologies, which have never been tested on the Mekong Mainstream. Pöyry makes no mention of the MRC's requirement that any fish passage technology must demonstrate a 95% success rate for key species passing through the dam. Scientific experts have concluded that no fish passage technology exists which could handle the broad diversity of species and tremendous biomass of fish migrations of the Mekong Mainstream.

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