Impacts of the Xayaburi hydropower dam planned for northern Laos are unclear as the proposal is poorly researched, says a technical report to the Mekong River Commission (MRC).
The four Mekong countries - Cambodia, Laos, Thailand and Vietnam - comprising the commission meet to make a final decision on the project next week.
The Xayaburi dam project is designed to churn out 1,285 megawatts. Thailand is expected to buy up to 90per cent of the output.
Thai environmentalists have vowed to stop Laos from going ahead with the dam. They say more information is needed to assess its impacts.
However, Vientiane in February told the Mekong countries that it would go ahead despite opposition.
It claimed the project would not have an impact on the environment and that it had full authority to approve the construction because the dam would be located in its territory.
A team of experts has now written a technical review to the commission which says design and operation models for the dam fail to meet best international practices.
The report refers to the project’s environmental impact assessments and feasibility studies, and its potential impacts on river flows and eco-systems.
Laos’ studies of the project, the experts’ report said, are incomplete, with crucial gaps in knowledge needed to understand its potential impact. Without that information, an accurate assessment of the implications could not be reached.
The four countries agreed to set up the MRC in 1995 to jointly manage their shared water resources and develop the economic potential of the Mekong River. The Xayaburi hydro power dam is planned for the lower Mekong River, which means it has to be reviewed by the commission for its possible environment impact and economic potential. In response, the Laos government said some of the report’s recommendations may be based on incorrect assumptions, especially concerning the likely impact on fisheries.
”Some substantial requirements mentioned in the MRC review are probably based on the wrong assumptions,” Laos said, citing an assertion that the water level in the river would not fluctuate after the dam is built.
Such an assertion made some of the report’s recommendations, such as the inclusion of ”nature-like fish passes” to allow fish to travel through during spawning seasons, more than questionable, it said.
The recommendations have ”an experimental character” and would be difficult to implement without studies.
Laos recommended more studies be carried out on fish biology, peak biomass, and fish swimming performance to help refine the design of the fish facilities.
It also questioned the role of the MRC in reviewing the proposal.
Hydropower was a form of green energy which should be promoted as an answer to power supply shortages.
Pianporn Deetes, a campaigner for International Rivers, said gaps in knowledge were a common problem in understanding the potential impacts of dam projects on the Mekong, including Xayaburi.
She said the Lao government should pay heed to the findings.
”The technical review has confirmed a crucial point that we need more knowledge to understand the Mekong River, on which millions of lives depend.
”What would be lost cannot be compensated by the benefits from the dam,” said Mrs Pianporn.
