Mekong River flow into Vietnam’s Mekong Delta expected to rise 10–30% in July: forecaster

In a monthly hydrological bulletin covering July 1–31, the station noted that increased upstream rainfall and early flood activity in Cambodia had raised river levels across the region.

A flood crest of 15.41 meters was recorded in Kratie, Cambodia on June 17 before gradually receding.

As of June 29, the average water inflow to the upper Mekong Delta through the Tan Chau and Chau Doc monitoring stations was 87 percent higher than the same period in 2024, and 40 percent above the multi-year average.

Based on these observations, the station forecasts that the total volume of water flowing from the Mekong River into the Mekong Delta in southern Vietnam in July will increase significantly, reaching 10–30 percent above historical averages.

The Mekong Delta, Vietnam’s largest rice-producing region, is highly dependent on seasonal water flows from the Mekong River, which affect agriculture, aquaculture, and daily livelihoods.

Between June 18 and 21, water levels rose rapidly across both upstream and downstream locations, driven by upstream flooding and high tides during the full moon. Levels were 20–80cm higher than in June 2024.

In the Long Xuyen Quadrangle, water levels throughout June were generally 5–45cm above last year’s levels.

A tidal surge between June 24 and 28, intensified by strong southwest monsoon winds, further raised river levels.

At the Xeo Ro station on the Cai Lon River, the peak water level reached 105cm on June 28, exceeding the highest-level flood warning threshold by 5cm.

In July, the station expects further increases in water levels in both upstream and downstream sections of the Mekong Delta, with peak levels likely to occur at the end of the month.

These are expected to be slightly below or near 2024 levels, while the lowest levels will appear in early July and rise gradually, exceeding last year’s by 20–70cm.

Tidal rivers such as the Cai Lon are projected to rise slowly, with peak and low levels forecast to be roughly similar to or slightly lower than July 2024.

The station warned of potential urban flooding in Long Xuyen and Rach Gie areas during periods of heavy rain combined with high tides.

It also noted increased risk of riverbank erosion along rivers, canals, and streams due to rising water levels and large tidal variations.