UBON RATCHATHANI, May 10, 2026 — A leading academic has raised serious concerns over the environmental impact assessment (EIA) of the proposed Phu Ngoy hydropower project on the Mekong River, warning of significant transboundary impacts on Thailand, including reduced electricity generation at the Pak Mun dam and flooding of a key पर्यटन site during the dry season.
Professor Dr. Kanokwan Manorom of the Mekong Sub-region Social Research Centre at Ubon Ratchathani University said the project should not proceed, citing clear risks outlined in its own documentation.
The Phu Ngoy hydropower project, planned for Champasak province in Laos near the Thai border in Ubon Ratchathani, is designed as a run-of-river dam on the Mekong mainstream. According to the EIA, the dam will operate at a full supply level of 98 metres above mean sea level, with a reservoir stretching about 80 kilometres along the river.
Dr Kanokwan said the EIA explicitly acknowledges that the project would cause backwater effects along the Mekong and its tributaries, including the Mun River in Thailand, particularly at Kaeng Tana, a well-known tourist attraction.
“The documents clearly show that this is a transboundary impact issue,” she said. “The project would alter water levels, affect ecosystems, and pose risks to communities on the Thai side.”
She added that supplementary documents prepared by the project developer, Charoen Energy and Water Asia Co Ltd, further reinforce concerns raised by Thai authorities during earlier consultations under the Mekong River Commission framework.
“When the EIA and supplementary report are read together, the conclusion is clear — this project should not go ahead,” she said.
Among the key findings, she said, Kaeng Tana would be submerged even during the dry season under normal operating conditions, with water level adjustments proposed only during major tourism periods such as New Year and Songkran.
The reports also indicate that water levels downstream of the Pak Mun dam could rise to around 100 MSL, potentially reducing its electricity generation capacity by about 41%.
At least 12 Thai communities, with a combined population of 6,738 people in 2,091 households, fall within the study area and may be affected by rising water levels. The documents also acknowledge significant data gaps, including the need for more detailed household-level assessments and improved baseline information on ecosystems and water quality.
The area is identified as a critical fish habitat, with 162 species recorded across 27 families. Of these, 110 species — or about 68% — are migratory, raising concerns over disruption to fisheries and livelihoods.
“These findings show that the issue is not about improving mitigation measures, but about whether the dam should be built at all,” Dr Kanokwan said. “Protecting the Mekong and Mun rivers requires halting new dams on the Mekong mainstream.”
She also called for greater transparency, including the disclosure of project documents in Thai, and meaningful participation by affected communities, particularly incorporating local and women’s knowledge.
Phairin Sohsai, campaign manager at Rivers and Rights Foundation, said the Phu Ngoy project is the fifth proposed dam on the Mekong mainstream involving a Thai private developer, and efforts have been made to push it through the prior consultation process under the 1995 Mekong Agreement.
She questioned whether the consultation process — known as PNPCA — was being treated as a de facto approval mechanism, despite ongoing concerns over environmental and social impacts.
“Hydropower has long been promoted as clean and affordable energy, but the transboundary impacts and the displacement of tens of thousands of people in Laos tell a different story,” she said.
She added that alternative energy options, including decentralised systems such as rooftop solar, are now more cost-effective and quicker to deploy than large dams.
“These alternatives should be prioritised, especially in a time of energy and geopolitical uncertainty,” she said.
A public forum titled “Phu Ngoy Dam: Facts, Impacts and Accountability” is scheduled for May 12 at Ubon Ratchathani University, organised by a civil society network monitoring flood risks and Mekong dams.
The event will bring together government officials, academics and community representatives to examine the project’s EIA, transboundary implications and the PNPCA process, reflecting growing scrutiny of large-scale hydropower projects on the Mekong.