Drought helps sea water penetrate further into Mekong Delta

Water levels in rivers, canals and reservoirs across the country have declined sharply compared to the same period in normal years due to prolonged drought, the Irrigation Department has said.

Dang Duy Hien, head of the department’s Irrigation Management Division, said reservoirs in the Tay Nguyen (Central Highlands) region are only 57-67 per cent full.

In some reservoirs in the south-eastern region, it is down to 42 per cent, he said.

The southern region has suffered a severe and prolonged drought this year with the dry season starting early — in late October — and the situation is more complicated now as it draws to an end, he said.

The early onset of the dry season and the drought have caused saline water from the East Sea to enter as much as 40-50km inland through rivers in the Cuu Long (Mekong) Delta.

The salinity in some areas here has been measured at 0.2-0.7 per cent, according to the Irrigation Department. Salinity of 0.4 per cent can damage crops.

More than 100,000 hectares of standing rice crops in Tien Giang, Tra Vinh, Soc Trang, Bac Lieu, Ca Mau, Kieng Giang, and Ben Tre provinces are suffering from a severe water shortage.

About a third of the delta’s residents face a shortage of fresh water.

Ben Tre is the hardest hit province, with saline water intruding into all parts. The provinces have closed sluice gates on river mouths to keep out the seawater.

The ministry has ordered drought-hit provinces to build temporary dams to keep out saltwater, dredge canals, and store fresh water in reservoirs, pools, and canals for irrigation.

It has also instructed them to consider measures to restructure cropping patterns to avoid damage from saline water in future.

According to the National Centre for Hydro-Meteorological Forecasting, the severe drought could persist until the end of this month.

The closure of sluice gates has not been always positive. It has badly affected shrimp breeding in the delta, especially in Soc Trang and Bac Lieu provinces.

In Bac Lieu’s Gia Lai District alone, 6,000ha of shrimp farms have been affected. Many shrimps have died due to the lack of saltwater, according to the district Agriculture and Rural Development Bureau.

More than 16,000ha of shrimp farms in the district now face a shortage of saltwater after sluice gates were shut to save more than 20,000ha of rice.

The province is now trying to regulate its irrigation system to benefit both rice and shrimp farmers, but it is a difficult task. —VNS

Tags: Mekong Delta, Vietnam agriculture