Floods across the Mekong River basin have been low this year due to low rainfall and increased dam storage. According to the Mekong Dam Monitoring Project (MDM), river levels across most of the Mekong basin are currently close to normal for this time of year. However, a recent large-scale dam storage in China is causing river levels in Chiang Saen, Thailand, to approach record lows for this time of year. Overall, river levels are trending downward and will continue to fall as upstream dams continue to store water.
Upstream hydroelectric dams increase water storage
Last week, the dams stored a total of 1.322 billion m3 of water. Hydroelectric dams stored more than 100 million m3 of water, including: Hoang Dang Dam (China), Tieu Loan Dam (China), Nam Khan 2 Dam (Laos), Nam Ngum 1 Dam (Laos)... In particular, Nua Tra Do Dam (China) released more than 100 million m3 of water for hydroelectric production. Nua Tra Do releasing water at this time of year is unusual.
“Water storage activities during the wet season will be detrimental to Mekong communities because they lower the Mekong River water level and reduce the benefits of Mekong flood flows,” according to MDM experts.
According to MDM, the Xayaburi dam's water release also caused the water level in the river downstream to rise suddenly, affecting the lives of people and fish raised along the river in Loei province (Thailand), killing them, and affecting some cultural activities in the capital Vientiane (Laos).
Low flood, early drought and salinity in the West
The National Center for Hydro-Meteorological Forecasting said: The El Nino phenomenon will continue until early 2024 with a probability of about 85 - 95%. As of August 14, the highest water level on the Tien River at Tan Chau was 1.99m, 0.45m lower than the average of many years (TBNN), on the Hau River at Chau Doc was 1.88m, 0.24m lower than the TBNN.
The Mekong Delta does not have a flood season, drought and salinity come early and are often severe.
From now until November 2023, the total flow on the Mekong River to the Mekong Delta tends to increase gradually and is 5-15% lower than the average. The water level in the upstream of the Mekong River tends to increase gradually and is likely to peak in late September and early October 2023 at alert level 1 and below alert level 1. However, the water level at downstream stations will reach its highest level in October and November at alert level 3 and above alert level 3, due to the influence of high tides.
The National Center for Hydro-Meteorological Forecasting said: During the dry season months of 2023 - 2024, the water level of the Mekong River upstream is strongly affected by the tide. Saltwater intrusion in the Mekong Delta is likely to come earlier and more severely than the average. Localities in the Southern Delta need to take proactive measures to prevent drought and saltwater intrusion.
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