Sluice gates to prevent salinity in Mekong tributary

By Hoang Nam   April 23, 2021 | 11:30 pm PT
Sluice gates to prevent salinity in Mekong tributary
A temporary dam built on the Nguyen Tat Thanh Canal that links with the Tien River, a tributary of the Mekong, in early 2021. Photo by VnExpress/Hoang Nam.
The government has approved the construction of six sluice gates on a tributary of the Mekong River to help keep out saltwater and store freshwater.

The Ministries of Agriculture and Rural Development and Planning-Investment have green-lighted a proposal by Tien Giang Province to build them on the Tien River in Chau Thanh and Cai Lay districts at a cost of VND880 billion ($38 million) using government funding.

The lands required will be acquired and cleared this year so that bids could be invited next year to award construction contracts.

They will help store freshwater to irrigate 128,000 hectares (316,300 acres) of farmlands and provide 1.1 million people in Tien Giang and neighboring Long An Province with water during the dry season from late November to early May.

"Tien Giang has had to spend tens of billions of dong every year to build temporary dams to prevent saltwater intrusion, and a permanent irrigation system will enable regulation of freshwater all year round instead of just the dry season," Ung Hong Nghi, deputy director of the Tien Giang Department of Agriculture, said.

For this year’s dry season the province built eight temporary dams in Chau Thanh and Cai Lay at a cost of VND45 billion ($1.95 million) to store freshwater, and dismantled them after three months as the rains arrived.

The Mekong Delta did not suffer as badly from salinity and a resultant lack of freshwater as last year, with the rainy season even arriving earlier than normal thanks to the La Nina phenomenon.

During the last dry season a salinity level of six grams per liter was found in some areas and one to four grams on average 50 km (31 miles) upstream, and up to 130 km, in all the tributaries of the Mekong.

Salinity of above one gram makes water unpotable and above two is unsafe for most crops.

Five provinces, Long An, Tien Giang, Ben Tre, Kien Giang, and Ca Mau, declared an emergency due to lack of water as salinity levels reached record levels. Around 40,000 hectares of paddies were damaged.

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