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Mekong Delta's saltwater intrusion may hit 45% by 2030

Released at: 10:31, 16/07/2016

Mekong Delta's saltwater intrusion may hit 45% by 2030

Photo: Duc Anh

Vietnam's main agriculture area exposed to a range of threats not always within the country's control.

by Minh Tuyet

Almost half of the Mekong Delta will suffer from saltwater intrusion by 2030 if hydroelectric plants upstream do not supply enough fresh water, the Ministry of Planning and Investment told a meeting with the South West Steering Committee on July 11.

In the first half of this year the El Nino weather pattern has been at its most severe for a century, the meeting heard, triggering serious drought and saltwater intrusion that have damaged rice paddy fields and fish and shrimp aquaculture.

Ten provinces are affected: Hau Giang, Tien Giang, Ben Tre, Kien Giang, Long An, Soc Trang, Ca Mau, Vinh Long, Tra Vinh and Bac Lieu. Saltwater intrusion has penetrated up to 80 kilometers inland, to a rate as high as 23‰, under which agriculture production cannot be conducted.

The 2015-2016 winter-spring rice cop fell 5 quintals per hectare compared to the previous crop. The Ministry of Agriculture and Rural Development said that, by June, about 83,000 ha of shrimp aquaculture had been damaged by saltwater intrusion.

The total damage to agriculture in the Delta stands at about VND4.687 trillion ($210.2 million). About 232,000 ha of paddy fields, 6,561 ha of vegetables, and 10,800 ha of fruit and industrial cops have been damaged, while 226,000 ha is short of water.

Deputy Minister of Planning and Investment Nguyen Van Hieu said that emerging challenges include not only climate change and saltwater intrusion but also hydroelectric plants upstream of the Mekong Delta. If there is insufficient water from upstream areas then saltwater intrusion cannot be controlled.

He added that the Delta’s agriculture sector will be exhausted within three years if Vietnam does not adopt the correct solutions.

Drought and saltwater intrusion resulted in the Mekong Delta’s growth in first half of year being -0.7 per cent.

With a long coastline of 3,260 km, Vietnam will be one of the countries most severely affected by climate change, in which the central coast, central highlands and the Mekong Delta are the three areas of most concern.

The Mekong Delta, consisting of 12 cities and provinces, was formed from alluvial sediments and accretion through changes in sea levels. The annual average water volume provided by the Mekong River is about 4,000 billion cu m together with about 100 million tons of silt materials, creating the most important agricultural area in Vietnam.

With its topographical features, the Mekong Delta will be affected directly by any change in the Mekong River’s water volume and the sea’s tidal pattern. If upstream areas are considerably affected by human activities, this will alter water flows downstream. For instance, the construction of hydroelectric dams upstream (in China) will regulate the amount of water and sediment reaching downstream, reducing the amount of water and sediment in the Delta. The exploitation of sand and gravel together with deforestation also changes the hydrology and silt in the area. Climate change has already resulted in substantial sea level rises near the Delta as well as increased rainfall, average temperatures, number of extreme weather events such as typhoons, and saltwater intrusion in the Mekong Delta. The Ministry of Natural Resources and Environment has announced that about 40 per cent of the Mekong Delta may become submerged due to climate change.

The central coast is largely formed from sand dunes and lagoons. The majority of the area is mountains and hills overlooking the sea with high slopes and fast flowing water, together with coastal cleavage plains. As a result, the region is easily impacted by changing conditions in climate and water resources.

The central highlands is plateau of basalt soil with thousands of square kilometers of rugged mountain peaks, so its complex temperature, rainfall and hydrology conditions are directly affected by vegetation cover that protects water and makes the climate equable. This area is the location of many important economic activities, such as hydroelectricity development, the development of industrial crops, and natural resources exploitation, leading to a loss of vegetation cover to protect water and soil. Changes in rainfall and wet seasons have increased the risk of desertification.

Ms. Nguyen Thi Thu Huyen, Deputy Director of the Department of Environment and Sustainable Development,
The Institute of Energy (Ministry of Industry and Trade)

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