With meteorologists forecasting a longer, harsher drought for the Mekong Delta this summer, authorities in the region's coastal provinces are trying to provide sufficient water for both crops and daily household use.
Coastal provinces on the southern side of the Hau River, one of the two main tributaries of Mekong River , are most vulnerable to seawater intrusion. The area, including An Giang, Kien Giang and Ca Mau provinces, is bordered by the sea on both sides.
|Vietnam News Agency photo of a dried reservoirs in Kien Giang Province's Ha Tien Town|
The fact that the Delta, which is partially inundated by Mekong 's tributaries during rainy seasons, surprisingly did not experience any flooding last year has raised fears that seawater may advance much further inland this year compared to previous years.
Salinity of four parts per thousand (ppt) has been detected around seven kilometres into rivers in An Giang province, which is 25km from the coast, said Vuong Huu Tien, deputy head of the provincial Department of Water Resources Management.
He noted that rice crops cannot withstand salinity of just one ppt.
"Farmers have finished harvesting the winter-spring crop, but we're concerned about next crop which starts shortly," he said.
"Seawater intrusion usually intensifies from the end of March to April."
The province has earmarked 40 billion VND (1.9 million USD) for dredging 99 rivers and canals and building five makeshift dykes that cost between 50-100 million VND (2,400- 4,800 USD) each to retain freshwater for irrigating 35,000ha of rice crop during the dry season this year.
These dykes, which are made of logs and sand, can stand for no more than a year and need to be renewed every year. The province is contemplating building composite dykes that can stand up to 20 years, but cost much more.
The province experienced two harsh dry seasons and seawater intrusion in 1998 and two years ago, and since then sluices have been built at river mouths to lock seawater from intruding during dry seasons.
Six more sluices will be built from 2015 to 2020 under a plan submitted to the government by Mekong Delta's Institute of Irrigation and Water Resources Planning, aiming to ensure that the west coast is fully safeguarded from seawater intrusion.
In the province's mountainous Tri Ton district, which borders coastal Kien Giang province, the sesame crop, which needs little irrigation, has replaced rice during the dry season.
Meanwhile, locals are fretting about the shortage of clean water, which is pumped from a nearby water plant.
"We have run short of tap water since the Tet (Lunar New Year) Holiday ," said Dang Van Hoa, 32, who lives at the foot of the Sa So Mountain. "Sometimes we do not have water for two straight days."
The shortage of clean fresh water is also a problem in Kien Giang province's seaside town of Ha Tien .
Almost 50,000 townsfolk rely on a reservoir in nearby Giang Thanh district which has a capacity of 1 million cubic metres, according to Duong Quang Binh, head of the town's Economy Department.
"For now, all the sluices of the reservoir have been closed to stop accumulating water due to seawater intrusion," he said, noting the town can only subsist for up to four months on current water reserves.
"If drought persists, we will have to pump freshwater from the nearby Vinh Te Canal," he said.
Shrimp farmers, meanwhile, were less affected by the salinity level in local rivers because they needed brackish water, he added.
The town had only 500ha of paddy fields but 3,000ha devoted to shrimp and crab farming, Binh noted.
"Floodwater in rivers during rainy seasons usually pushes seawater away from the coast," he said.
"But last year it did not happen," he added, "So seawater will surely advance further inland during the dry season this year."
Sluice gates on 27 estuaries across the province have been closed following the poor flooding season last year in anticipation of acute drought this year, according to the provincial Department of Water Resources Management.
Neighbouring Ca Mau province, which is home to the U Minh Ha National Park, has also speeded up construction of sluice gates at river mouths to make sure that the vast cajeput forest is safe from seawater intrusion.
Along a coast stretching 32 kilometres of U Minh district, workers are working on several sluice gates that cost dozens of billions of dong each.
The district has completed the Tieu Dua and Lung Ranh Sluice Gates, and three more are set for completion from now until 2020, according to Nguyen Hoang Ghi, head of the district's Department of Water Resources Management.
Source: Vietnam News Agency