Fundamental differences of opinion between Laos and Cambodia, Thailand and Vietnam over a proposed US$3.8 billion dam on the lower Mekong, which many fear could have devastating consequences for the region, came to a head yesterday when they failed to reach a common position at a crunch meeting.

Representatives of the four countries yesterday passed over a decision on whether to end discussion on the proposed Xayaburi dam in Laos to a ministerial level because “they could not come to a common conclusion on how to proceed with the project,” according to a statement released by the Mekong River Commission, a regional intergovernmental body created to manage the river.

Laos remained defiant during the meeting in its capital, despite strong concerns from its neighbours and growing international criticism about the dam’s consequences, saying environmental impact on other countries was “unlikely”, the statement said.

Viraphonh Viravong, the head of the Lao delegation, said “major impacts on navigation, fish passage, sediment, water quality and aquatic ecology and dam safety can be mitigated at acceptable levels”, according to the release.

Yet an estimated 41 fish species, including the endangered Mekong Giant Catfish – the largest freshwater fish on the planet – could face extinction if the dam is built, bringing irreversible changes to this fish-dependent region, according to the conservation group International Rivers.

Dozens of other species may not be able to migrate, the organisation said. Laos was reported to have said it would not be possible to satisfy “all parties’” concerns and argued that an extension of the consultation process was not practical.

Cambodia, Thailand and Vietnam all called for more information and time to consider the dam, saying that the six-month consultation process was inadequate, according to documents made public yesterday.

The Cambodian delegation requested that the project be delayed, citing the “limited information”, technical gaps, and the need for a comprehensive assessment of cross-border and environmental impacts.

Vietnam said that it had already felt negative impacts from Chinese-built dams built on the upper reaches of the Mekong and that mainstream dams would present “serious threats to the Mekong Delta”.

It said the Xayaburi dam and any other mainstream hydropower projects should be deferred for at least 10 years, if not cancelled outright. Thailand, which has agreed to purchase an estimated 95 percent of the energy from the dam, also said the regional conversation should continue, citing potential losses of fisheries and wetlands and questions about the sustainability of the project as a whole.

Te Navuth, who is secretary general of the Cambodian National Mekong Committee but served as a neutral chair of the meeting, said the meeting between ministers from the four countries, who exert overall governance authority over the MRC, had been set tentatively for October or November this year.

Lim Kean Hor, Minister of Water Resources and Meteorology, who will represent Cambodia at that meeting, could not be reached yesterday.

The Bangkok Post reported on Sunday that major road construction was well underway and printed photographs of a fleet of trucks and diggers with the logo of CH Karnchang Public Company Limited, the Thai company heading the project.

Te Navuth said that they did not discuss the recent reports of infrastructure construction around the dam, but would “seek clarification from Laos about this information”.

He added the MRC has “not been informed officially about any work on the site”.

Hydropower development is central to the Lao government’s development policies. Currently, Laos has signed memorandums of understanding or is making plans for more than 70 hydropower projects, 15 of which are operational or under construction, according to the Lao Ministry of Energy and Mines’ Department of Energy Promotion and Development.

Laos committed in 2007 to provide 7,000 megawatts of energy to Thailand, 5,000 megawatts to Vietnam and 1,500 megawatts to Cambodia by 2015.