Five Mekong provinces warned as Laos dam raises discharge
Five northeastern provinces are warned of a possible 1.3-metre Mekong rise as Laos’s Nam Theun 1 dam increases its discharge after heavy rain
Authorities have warned five northeastern provinces to prepare for a sharp rise in the Mekong River after the Nam Theun 1 hydropower dam in Laos increased its discharge following persistent monsoon rain.
The Office of the National Water Resources said water levels along the Thai side of the Mekong could rise by about 60 centimetres to 1.3 metres between July 17 and 20.
The warning covers Bueng Kan, Nakhon Phanom, Mukdahan, Amnat Charoen and Ubon Ratchathani, particularly low-lying communities close to the riverbank.
In Bueng Kan, Bung Khla and Bueng Khong Long districts were identified as areas requiring close monitoring.
The warning does not mean that flooding is certain, but authorities said rising river levels could cause water to overflow into vulnerable riverside areas.
Heavy rain forces change to dam discharge plan
Continuous heavy rain associated with the monsoon has raised the volume of water in the Nam Theun 1 reservoir in Laos.
Information received from the Lao authorities on July 16 showed that the dam would adjust its discharge through the spillway from July 17.
The initial discharge was set at about 200 cubic metres per second before being gradually increased to between 1,000 and 2,500 cubic metres per second.
At the maximum rate, the discharge would be 12.5 times the initial 200 cubic metres per second.
The National Water Resources Office said the increased flow could push up the Mekong from Bung Khla and Bueng Khong Long districts in Bueng Kan downstream through Nakhon Phanom, Mukdahan, Amnat Charoen and Ubon Ratchathani.
The rise was expected to occur between July 17 and 20.
Five provinces told to monitor riverside areas
The five provinces covered by the warning are:
- Bueng Kan: Bung Khla and Bueng Khong Long districts are expected to be among the first Thai areas affected by the higher flow.
- Nakhon Phanom: Authorities and riverside communities have been advised to monitor changes in the Mekong closely.
- Mukdahan: Low-lying areas beside the river could face an increased risk if water levels rise rapidly.
- Amnat Charoen: Officials have been told to prepare for possible effects in communities connected to the Mekong river system.
- Ubon Ratchathani: Downstream areas should remain alert as the increased flow moves southwards.
The Office of the National Water Resources forecast that Mekong levels in the affected areas could rise by approximately 0.60 to 1.30 metres during the warning period.
River remained below its banks before release
Available measurements on July 16 showed that the Mekong remained well below its banks before the higher discharge began.
At the Bueng Kan monitoring station, the river was 6.43 metres below the bank, while the level at Nakhon Phanom was 5.61 metres below the bank.
However, authorities warned that conditions could change as the additional water moved downstream and combined with rainfall and other inflows into the Mekong system.
Local agencies and residents in vulnerable riverside areas were advised to monitor official updates, prepare to move belongings to higher ground where necessary and remain alert to rapidly changing water conditions through July 20.
