Water levels in the Lower Mekong River Basin (LMB) have increased rapidly and are projected to rise further over the next five days – especially from Chiang Khan to Khong Chiam in Thailand and Vientiane to Savannakhet in Laos, says the Mekong River Commission (MRC) Secretariat.
According to the MRC’s observed water levels and rainfall data, heavy rainfall across the Mekong region – which began on 5 August – has contributed to the rise, putting the river levels in most monitoring stations above their long-term values.
“The region has received more than average rainfall in August alone, or approximately 40 percent higher than it was in 2021 and 2022 over the same period,” says Dr. Sothea Khem, the MRC Secretariat Flood Forecasting Specialist.
Due to low pressure in the LMB, Dr. Khem adds, some parts of Laos and Thailand were hit harder by flash floods last weekend. The situation has since increased water levels and affected properties and livelihoods.
In Thailand’s Chiang Khan, the station water level jumped from 7.70 meters to 12.26 meters during 1–8 August. Over the next five days, a further rise of 0.50 meters is expected. Its alarm level is 14.5 meters.
Vientiane Capital saw its river level jump by 4.30 meters over the same period, an increase of about 40 percent. Over the next five days, the river level is projected to rise between 2.34 meters and 3.32 meters. The expansion will put the station level in the alarm state (11.5 meters), while the flood warning is 12.5 meters.
From Nakhon Phanom in Thailand to Pakse in Laos, the river levels rose by more than 2.50 meters and will see an up of about 2 meters over the next five days. As a result, the water level at Nakhon Phanom will reach its alarm level of 11.5 meters on 10 August and flood level (12 meters) on 11 August.
In Cambodia, water levels from the stretches in Stung Treng to Kratrie increased from 0.92 meters to 2.59 meters over the same period. Over the next five days, the levels are likely to drop from 0.20 meters to 1 meter.
In Vietnam’s Mekong Delta – Tan Chau on the Mekong River and Chau Doc on the Bassac River – the water levels fluctuated and remained lower than their long-term values due to tidal effects.
The outflows at Jinghong hydrological station in China on the Upper Mekong Basin, however, saw a fluctuation over the same period. From mid-to the end of June, there was an average dip of 1.33 meters per day in its water level.
Xayaboury dam “may” release water
The Xayaboury hydropower operator has warned it may release water from its dam over the coming days and downstream communities should be prepared for the changes in river levels, according to a notification to the Lao Ministry of Energy and Mines.
The 7 August notification said “Due to continuous heavy rainfall in Laos affected by the Khanun tropical storm and water discharge from other upstream hydropower plants” the inflow at the Xayaboury dam has increased.
The operator has warned the communities both upstream and downstream of the dam to be prepared for further changes in river levels, especially for any “short notice” of water releases. The same operator added that it had already “activated the appropriate emergency action plan”.
More information and regular updates on river monitoring and flood forecasting can be found on the MRC social media and its website at www.mrcmekong.org.
