Plans for building a massive dam in Laos have been put on hold. The intergovernmental panel of the Mekong River Commission (MRC) has deferred the final decision on the construction of the Xayaburi dam in Laos to the ministerial level, following concerns raised by Cambodia, Thailand and Vietnam.

The decision comes amid the submission of a growing body of evidence to the Commission highlighting risks to biodiversity, fisheries and livelihoods of millions of people in the Mekong River Basin. Particularly vulnerable areas include fisheries and the Mekong Delta.

A WWF-commissioned review of the Xayaburi project found that the environmental impact assessment (EIA) and feasibility study (FS) for the proposed dam were woefully inadequate and fell well below international standards for such studies. Changes in flows, sediment and nutrients were some of the areas requiring further analysis, said the WWF.

The decision will have implications for generations to come ‘Any decision made will have implications for generations to come,' said Dr Jian-hua Meng, WWF International Sustainable Hydropower Specialist. 'It is clear that the governments of Cambodia, Thailand and Vietnam are acknowledging the gaps in knowledge of the expected impacts from the dam.'

An experts meeting held in Vientiane in 2008 to review the impact of mainstream dams on fish migration concluded that existing mitigation technology used for salmon species in Europe and North America cannot handle the scale of fish diversity and migration in the Mekong mainstream. WWF believes that the Mekong should not be used as a test case for proving or improving fish passage technologies.

WWF is now supporting a ten-year delay in the approval of lower Mekong mainstream dams, including the Xayaburi hydropower dam, to ensure a comprehensive understanding of all the impacts of their construction and operation, while immediate energy needs are met with less challenging projects applying state of the art sustainable hydropower solutions are fast tracked on selected tributaries.

'The MRC has taken an important step towards responsible decision-making and is clearly looking at the potential impacts the Xayaburi dam would have on millions of people in the Mekong River Basin,' Dr Meng said. 'Laos needs to build on the knowledge gained in developing sustainable hydropower in the region and follow examples such as the Nam Theun 2 dam.'