Mekong River Water Levels See Big Jump Due to Torrential Rain

Horses chew on grass by the Mekong River in Vientiane Capital (Photo: Jason Rolan)
Horses chew on grass by the Mekong River in Vientiane Capital (Photo: Jason Rolan)

Lower Mekong River Basin (LMB) water levels have increased significantly over the last seven days but some sections will see a slight dip over the next five days, the Mekong River Commission (MRC) Secretariat says.

Heavy rainfall throughout the Mekong region that started at the beginning of June has contributed to the rise, with recorded river levels at most monitoring stations above their long-term values, according to MRC’s observed water level and rainfall data.

“The region has received approximately 60% higher than average rainfall this month when compared to the same period in 2019 and 2020,” said Dr. Lam Hong Son, Head of the MRC Secretariat’s Regional Flood and Drought Management Centre, noting that rainfall will be lower than average in July and about average in August and September.

He added that due to tropical storm Koguma, many areas of Lao PDR were struck by flash floods last weekend, triggering landslides and widespread damage to property.

The water level in Thailand’s Chiang Saen, the uppermost monitoring station in the LMB, increased from 3.14 metres (m) to 4.52m between June 9 and 16, a rise of 1.38m. During the next five days the river level is expected to drop by about 0.15m.

In Thailand’s Chiang Khan, located downstream of the Xayaburi dam in Lao PDR, the station’s water level jumped to 9.23m from 5.67m during the same period. But the level is forecast to fall over the next five days by approximately 0.60m.

Meanwhile, Lao PDR’s capital city Vientiane saw its river level jump more than 3.50m last week but the level is expected to drop by about 0.70m over the next five days. From Nakhon Phanom in Thailand to Pakse in Lao PDR, river levels rose more than 2.50m but will likely drop approximately 0.60m over the same period.

In Cambodia, water levels in the stretches from Stung Treng to Neak Luong in Prey Veng were reported to have increased by 0.65m in the same period. During the next five days, levels are forecasted to rise by a further 0.60m.

In Vietnam’s Mekong Delta encompassing Tan Chau on the Mekong River and Chau Doc on the Bassac River, water levels fluctuated close to their long-term values as a result of tidal effects.

Elsewhere, outflows at Jinghong hydrological station in China on the Upper Mekong Basin saw a slight fluctuation over the same period. This followed rapid variations between the middle and end of May that saw an average drop of 1.33m per day in the water level.

The MRC continues to monitor water levels across the Mekong region amid erratic weather patterns.