Updated Wednesday, November 7, 2012 at 12:46 AM
BANGKOK — Ignoring criticism that a huge hydroelectric dam could irreparably damage the ecology of the Mekong River, the government of Laos said Tuesday that it was pushing ahead with the multibillion-dollar project, the first dam to be built on the lower portion of the iconic river.
"I would say I'm 100 percent sure it's going ahead," Daovong Phonekeo, deputy director general of the Laotian Department of Electricity, said by telephone Tuesday.
Laotian government officials and executives of a Thai construction company that is to build the dam are to officially inaugurate the project at a ceremony Wednesday in Xayaburi, the remote province in northwestern Laos where the dam is to be situated.
The electricity from the project will be sold to Thailand and will provide billions of dollars of revenue to Laos, one of the poorest countries in Asia. But the project has been criticized by scientists concerned that the dam may disturb spawning patterns and lead to the extinction of many species of fish that for centuries have been the main source of protein for millions of people along the river's banks.
The U.S. State Department issued a statement Monday questioning the rush to complete the dam.
"The extent and severity of impacts from the Xayaburi dam on an ecosystem that provides food security and livelihoods for millions are still unknown," it said.
The State Department said it was concerned that countries sharing the river "have not reached consensus on whether the project should proceed."
The Mekong River passes through parts of Thailand, Cambodia and Vietnam before emptying into the South China Sea.
Although the dam is being constructed on a part of the Mekong River that is entirely inside Laos, riparian countries of the lower Mekong signed an agreement in 1995 to consult with one another before proceeding with large projects on the river.
Laos appears to have steamrollered through that process despite objections raised at a meeting last December, when representatives from Vietnam and Cambodia called for further studies.
Laos says it is satisfying the requirement to consult with other countries — but only consult.
"This is not an international issue," said Daovong, of the Department of Electricity. "It's more an internal affair."
That approach has left environmentalists incensed.
"It's unbelievable that just a small group of people who hold power are able to doom the river," said Pianporn Deetes, a Thai environmental activist who was born and grew up near the Mekong in northern Thailand.
"We are not just crazily opposing the project," she said. "What we want is some information on the pros and cons."
Thai environmentalists say there is a troubling precedent: A dam constructed two decades ago in northeastern Thailand on the Mun River led to the disappearance of nearly two-thirds of the 265 species in the river.
Laotian officials and Thai executives involved in the Xayaburi project dismiss criticism of the dam as the misinformed concerns of a small group of activists.
Environmentalists are "trying to stir up controversy and anger among uneducated villagers and mislead people," Rewat Suwanakitti, deputy managing director of Xayaburi Power, the company leading the project, said by telephone.
Hans Guttman, chief executive of the Mekong River Commission, the advisory organization that coordinates studies and meetings among the four lower-Mekong countries, said Laos had proposed several changes to address criticism, including a system that would flush sediment downstream and a revised "fish ladder" to help fish reach spawning grounds.
But the Laotian government has not yet provided a revised blueprint, Guttman said.
"We have not seen it and we are not aware of it," he said.
The Thai foreign minister, Surapong Tovichakchaikul, said Tuesday that the government was "not opposed" to the dam.
Construction will begin "right after the ceremony" on Wednesday, said Rewat, the Xayaburi Power executive.
Much work already has been done. C.H. Karnchang, a Thai company carrying out the construction, has spent the past two years building access roads and hauling equipment to the site.
JUSTIN MOTT / NYT
Much preparation already has been done for construction of the Xayaburi dam on the Mekong River in Laos, which was to begin immediately after a ceremony Wednesday. Power from the project is to be sold to Thailand.