The flow of the Mekong River in the delta in the last months of this year and early next year is estimated to be 20-40 percent lower than the average of many years, according to the National Centre for Hydrometeorology Forecast.
It is the peak time of the delta's flooding season but the river's water levels at upstream areas in An Giang and Dong Thap provinces are about 2 metres lower than in previous years.
In provinces located in the Long Xuyen Quadrangle and Dong Thap Muoi (Plain of Reeds) regions such as Dong Thap, An Giang, Long An, Tien Giang and Kien Giang, farmers every two or three years do not plant an autumn-winter rice crop in order to clean and fertilise fields with flood water.
In An Giang Province, for example, farmers this year have not planted the autumn-winter rice on a total area of 156,000ha to let flood flow into rice fields.
However, no floods come and farmers have had to pump water into rice fields.
Ngo Van Loi, chairman of the Lang Bien Commune Rice Seed Producer Club in Dong Thap Province, said: "I've grown rice for more than 40 years but I've never seen any year like this year. My area is located in flood-prone areas in Dong Thap Muoi but has had no floods."
"Every year I have to release floods out of rice fields to sow rice seeds, but this year I had to pump water into the field, which costs money," he said.
About 620,000 hectares of the winter-spring rice in coastal areas, including in Bac Lieu, Soc Trang, Tra Vinh and Tien Giang provinces, are threatened by saline intrusion, according to the Ministry of Agriculture and Rural Development's Plant Cultivation Department.
The department has told delta provinces and Can Tho City to try to finish the winter-spring crop by mid-January 2016.
Rice fields located 25-30km from the sea will not have fresh water for irrigation beginning in February because of saline intrusion.
The department has also told delta provinces to prepare pumps and close sluice gates to keep fresh water for the winter-spring crop.
