Explaining the increase in saltwater intrusion in the Mekong Delta waters

On April 25, reporting on the prevention and control of drought and saltwater intrusion in the Mekong Delta (MRD), the Department of Irrigation (Ministry of Agriculture and Rural Development) said that the water source is from the upstream of the river. Mekong and the Mekong Delta have changed greatly in terms of rules, due to the influence of the operation of reservoirs.

According to the Department of Irrigation, the total flow in the dry season increases, but the flow at the beginning of the dry season tends to decrease, increasing in the middle and end of the season.

Fluctuations in upstream water sources cause salinity intrusion in estuaries and coastal areas to have major changes in rules.

Before 2012, salinity usually came from February to April, with peak salinity at the end of March-April, which is the month with the lowest flow.

But currently, in years when the upstream flow is low, salinity intrusion appears from the end of December of the previous year and the salinity peak is in February or early March of the following year.

For the 2023-2024 dry season, saltwater intrusion will begin to appear from the end of December 2023, about 33 days earlier than the average of many years.

In particular, from April until now, saltwater intrusion in the West Coast has fluctuated unpredictably, with some times the salinity increased dramatically, especially from April 18 to April 22.

Explaining the cause of increased saltwater intrusion in the sea, the Department of Irrigation said that due to the low level of upstream water sources reaching the Mekong Delta in April 2024, combined with prolonged heat, the amount of water in the Mekong Delta was low. high water evaporation.

In addition, localities simultaneously planted seeds for the summer-autumn crop, causing the water level in the field to rapidly decrease; The internal water source demarcation project has not been completed…

Currently, the Mekong Delta has about 1,580 hectares of rice (1,530 hectares in Soc Trang, 50 hectares in Ben Tre), 4,640 hectares of lemon and other fruit trees in Long An that are at risk of reduced productivity.

In addition, 43 hectares of rice in Soc Trang province were completely lost.

According to statistics, about 73,900 households (2.1% of rural households) are affected by lack of domestic water, concentrated in 7 provinces (Long An, Ben Tre, Kien Giang, Tra Vinh, Soc Trang, Bac Lieu and Ca Mau).

The number of households affected by water shortages is lower than in 2019-2020 (96,000 households) and the level of impact on households is also low, the duration of impact is short, only occurring a few peak days in the middle of the month. 3.

The Department of Irrigation assesses that in the Mekong River estuary region, saltwater intrusion has reached the highest peak of the dry season from March 10 to 13, saltwater intrusion episodes have appeared on March 24-28, April 7-11 is lower than the peak but still maintains a relatively high level.

It is forecasted that the remaining high salinity intrusion is expected to appear on April 23-27. From May, saltwater intrusion will continue to decrease, no longer affecting water sources for agricultural production from the beginning of June. .