The Mekong River Commission (MRC) said on Monday that the river's water level in Kratie province is expected to decrease by 50cm to 1.5m from April 12-19, as the outflow from China's Jinghong hydropower station is gradually reduced by half to accommodate the Dai ethnic group's celebration of the Water Splashing Festival.
The Mekong's water level in Laos' Luang Prabang province will be similarly affected, while the level in Thailand's Chiang Saen district in Chiang Rai province may decrease by 70cm to more than 1m from April 12-21, the comission said.
The MRC quoted an official notification from China's Ministry of Water Resources as saying that on April 11, outflow from the Jinghong hydropower station will start decreasing from 2,000-3,000 cubic metres per second to 1,500–1,600 cubic metres per second.
The amount of water flow will gradually be returned to normal starting on April 17, the statement said.
The Jinghong dam lies on the upper Mekong River (known as the Lancang in China) in Yunnan province.
Leang Bunleap, the executive director of 3S Rivers Protection Network, expressed concern that the reduced water flow from the Chinese dam will increase the Mekong's temperature in Kratie province, possibly resulting in the death of some species of fish.
He said villagers in some areas may experience a shortage of water, as wells could run dry. "Regarding the water in villagers' wells, when the Mekong River level decreases, wells with only a small amount of water will be vulnerable.
"We have already had warnings of the dry season being prolonged in May and June. This will only make things worse and affect the livelihoods of people and animals," Bunleap said.
Chhnieng Lorn, from the fishing community at the Prek Kampi dolphin pool in Kratie province's Sambor district, said the lower water level will not affect dolphins.
"Even if the level of the Mekong River decreased almost two metres, it wouldn't be a problem because the dolphin pool is very deep," he said.
The Post could not reach Ministry of Water Resources and Meteorology spokesman Chan Yutha on Tuesday.
China's Ministry of Water Resources said that during the week-long reduced water outflow from the Jinghong hydropower station, there would be no serious effects for wildlife or for people who live along the Mekong River.
"China's notification is helpful to downstream countries and their communities. It enables people to prepare for any possible risks and to maximise productivity along the Mekong mainstream," MRC secretariat chief executive officer An Pich Hatda said.