The Mekong Delta is bracing for heightened saltwater intrusion, as dry season water flows continue to decrease, according to the latest report from the Vietnam Mekong River Commission.
The phenomenon threatens agricultural production and freshwater supplies in one of the country’s most important rice-producing regions.
Authorities have urged localities to optimize saltwater prevention measures and proactively store freshwater to mitigate the impact on farming and daily life.
Hydrological forecasts from the National Center for Hydro-Meteorological Forecasting and the Mekong River Commission suggest that total rainfall across the Mekong Basin in March will remain close to the long-term average, with variations of 5%-20% across different sub-basins.
While upstream areas are expected to receive rainfall at levels similar to previous years, the Mekong Delta and northeast Thailand may experience a slight increase.
Reservoirs along the Lancang River are currently at approximately 75% of their total capacity, while those in the lower Mekong Basin are at about 60%.
Hydroelectric generation is expected to continue, further influencing downstream water levels.
At Kratie Station in Cambodia, flow is estimated to decline, with total discharge in March estimated at 6.4 billion-8.2 billion cubic meters. Meanwhile, the Tonle Sap Lake, which plays a critical role in regulating water levels, currently holds about 2.2 billion cubic meters, limiting its contribution to the main Mekong River.
According to the Vietnam Mekong River Commission, water levels in key monitoring stations will fluctuate but remain below average.
At Tan Chau Station in Tay Ninh Province, peak daily water levels in March are expected to range from 1.1 to 1.6m. The average daily discharge is estimated between 3,000 and 4,500cu.m per second, which is comparable to historical averages, but 5% lower than in 2024.
At Chau Doc Station in An Giang Province, water levels are forecasted to range from 1.2 to 1.6m. The average daily discharge is expected to be between 250 and 480cu.m per second, representing a 24% drop from historical averages and a 6% decline from last year.
Flow levels at Chau Doc in March are projected to fall between 1 and 1.1 billion cubic meters, down by 18%-29% from historical norms and 0%-11% lower than the same period in 2024.
Based on flow and tidal projections, the one gramme per liter salinity boundary is expected to push 3-13 kilometers further inland along the Hau, Tien, and Vam Co Tay rivers, compared to the averages in the past. The four grammes per liter salinity boundary, a critical for agriculture, is also forecasted to extend 3km-10km deeper inland.
Local areas are being urged to closely monitor water sources, store freshwater and implement proactive measures to counteract the worsening saltwater intrusion. Areas at high risk should stay updated on salinity monitoring and forecasts to adjust their mitigation strategies accordingly.
According to the Head of the Central, Central Highlands, and Southern Hydrological Forecasting Division at the Ministry of Agriculture and Environment, Phung Tien Dung, the 2024-2025 dry season is expected to see above-average saltwater intrusion, although not to the extreme levels experienced in 2015-16 and 2019-2020.
Saltwater intrusion is shaped by upstream flows, tidal patterns and shifting environmental factors. Peak intrusion at the Mekong River’s estuaries, Vam Co and Cai Lon rivers is anticipated this month and across April.
Several districts are particularly vulnerable to saltwater intrusion, including Long An, Tien Giang, Ben Tre, Tra Vinh, Soc Trang, Bac Lieu, Kien Giang and Hau Giang provinces. (VietnamNews)