As sea levels rise along the coasts, saltwater can move onto the land. Known as saltwater intrusion, this occurs when storm surges or high tides overtop areas low in elevation. It also occurs when saltwater infiltrates freshwater aquifers and raises the groundwater table below the soil surface.
According to local media, saltwater intrusion has begun to make its way into provinces near the Mekong River, affecting the irrigation of crops.
Some 60,000 hectares of rice and over 43,000 hectares of fruit in the Mekong Delta’s coastal provinces are at risk of being contaminated by saltwater, said the Directorate of Water Resources.
Saltwater is expected to enter 45-55 kilometers deep into the estuaries of the Mekong River, with the salinity rate reaching four grams per liter, the Vietnam News Agency reported, citing data from the authority.
Most plants can only tolerate a rate of one gram per liter.
It will intrude 60-70 kilometers deep into the Vam Co River in February, some 5-7 kilometers higher than the year-ago period.
The intrusion often worsens during high tide, affecting irrigation systems within 30 to 50 kilometers of sea mouths in the Mekong River and up to 60 kilometers in the Vam Co River.
Saline intrusion in the area near the Cai Lon River may be under control thanks to the Cai Lon and Cai Be sluices.
Local authorities have taken various measures to mitigate impacts of saltwater intrusion.
Saltwater contamination occurs during the dry season, between December and April, local media reported.