Vientiane Times, May 13, 2014
Xayaboury hydropower plant, which is currently under construction on a section of the Mekong River in northern Laos, is designed to withstand a strong earthquake, according to the project consultant.
Director of Hydropower & Renewable Asia of Pöyry Energy Ltd, Mr Knut Sierotzki made the comments yesterday amid worries that the strong earthquake that damaged buildings and roads in Chiang Rai, Thailand, on May 5 could cause negative impacts to the dam.
“The epicentre of the magnitude 6.3 Chiang Rai earthquake was more than 200 km away from the Xayabury Hydropower Project site,” he said. “The ground shaking occurring at such distances could be felt by people but was of no concern for well-designed and constructed dams.”
“No effects of this earthquake could be detected at the Xayabury dam site.” The May 5 event occurred at a fault zone which is not related to the Dien Bien Phu Fault Zone that passes near the Xayabury dam project.
The design of the Xayabury dam has been designed to withstand earthquakes of a greater magnitude than the Chang Rai tremor within the immediate vicinity of the dam, Mr Sierotzki explained.
Moreover, the damage caused by this earthquake was mainly observed in structures on soil whereas the Xayabury dam is located on sound bedrock, he added.
Furthermore, as the maximum change in water level at the Xayabury dam site is less than 40 metres, the possibility of triggering earthquakes due to the filling of the reservoir is very small.
The magnitude of such events is also smaller than the maximum credible earthquake considered in the dam design, Mr Sierotzki said, and therefore they pose no threat to the safety of the dam.
The earthquake considered in the design of the Xayaburi project is called ‘maximum credible earthquake,’ which is expected at the site, he explained, without giving further technical specifications.
Such earthquakes may never occur during the lifespan of the dam which may be well over 100 years if it is properly maintained. Therefore, there is no concern that this dam may threaten any people living downstream during a strong earthquake, Mr Sierotzki said.
Thailand’s Royal Irrigation Department says its dams located in the Chiang Rai area experienced strong ground shaking.
These dams are mainly irrigation dams and no damage has been reported to any of them. All dams in the vicinity of the earthquake zone behaved in accordance with expectations.