Soil instead of concrete in the foundations of collapsed dam
On 23 July 2018, five billion cubic metres of water flooded 12 villages in the south of the country. The disaster left at least 40 people dead with scores of missing. According to international experts, construction defects were fatal. The South Korean company that owns the plant has rejected the findings.
Vientiane (AsiaNews/Agencies) – The fatal collapse of a dam at the Xe-Pian Xe-Namnoy (PNPC) hydroelectric plant on 23 July 2018 was caused by poor construction methods with soil used in lieu of concrete.
The Laotian government made the announcement yesterday, citing the conclusions of the International Expert Panel (IEP) that investigated the case.
Following the collapse of the structure, five billion cubic metres of water inundated 12 villages in the southern provinces of Champassak and Attapeu, killing at least 40 people with scores missing.
The disaster forced the authorities of neighbouring Cambodia to evacuate thousands of residents living on the banks of the Sekong River.
“The International Expert Panel (IEP) found that the major cause of the Xe Pian Xe Namnoy dam collapse was the high-absorbency of the foundation of saddle dam D, coupled with soil being porous and easily eroded, and the level of rising water,” said Singpheth Bounsavathiphanh, vice chairman of the Government Inspection Authority and vice chairman of the Lao National Investigation Committee.
“Those conditions caused erosion within the foundation … When the erosion reached a certain level, the dam became unstable and sliding began at the higher saddle dams. At some point, saddle dam D broke, causing a massive amount of water to flow out of the reservoir.”
PNPC is a consortium formed by a local Lao company and South Korea’s SK Engineering & Construction.
Korean involvement in the project prompted South Korean authorities to send relief teams to Laos to help mitigate the effects of the disaster. Experts from China, Vietnam and Thailand also took part in the operations.
Shortly after the release of the report on Tuesday, SK Engineering & Construction dismissed the IEP’s findings and questioned the scientific basis of its approach.
For now, a new saddle dam is now under construction at a location a little more than a kilometre away from the dam that failed.
Officials have said that the new 400-metre-long structure will be built with concrete and anchored at a depth of at least 10 metres into the ground.
In the wake of the Xe-Pian Xe-Namnoy disaster, Laos is reviewing its ambitious hydroelectric dam plans.
The latter is meant to turn the Southeast Asian nation into the "battery of Asia" to sell hydropower to its more industrialised neighbours like China, Thailand and others.