Piet Hoekstra from Utrecht University in the Netherlands cited a report of the ‘Rise and Fall’ project as saying that the Mekong Delta subsides 2-4 cm each year with the coastal lowlands being the most seriously stricken areas.
Ky Quang Vinh, chief secretariat of the Can Tho City’s Steering Committee on Climate Change, confirmed 2-4 cm subsidence each year in the area, saying that it was caused by the overexploitation of underground water.
“The underground water layers are getting nearly depleted with the water level falling dramatically,” he said at a workshop held in Can Tho City in late March.
Piet Hoekstra said that underground water overexploitation is the major reason behind the subsidence in Mekong Delta.
|Land subsidence in the Mekong Delta is becoming increasingly serious, caused mainly by overexploitation of underground water.|
The expert said that thick compressed layers of sediment, and the development of infrastructure items such as roads, high-rise buildings, large construction works and geological tectonics faults are other causes of land subsidence.
Mekong Delta is witnessing big changes in the urbanization process and the use of land to meet socio-economic development goals. All of these factors have caused big challenges to the region.
One of the challenges, according to scientists, is the increasingly high demand for water for daily use and production. This leads to increased exploitation of underground water resources, which, in turn, causes underground water depletion and higher possibility of land subsidence.
The underground water overexploitation will lead to more saline intrusion, flood risks, and loss of arable land, and will affect infrastructure works.
Tran Van Thanh, director of the Soc Trang provincial Department of Natural Resources and the Environment, said the underground water exploited capacity has exceeded the safety level.
“The underground water level has been decreasing in Soc Trang City, My Xuyen district and Vinh Chau Town,” he said.
Vinh has urged state management agencies to stop licensing underground water exploitation immediately. Japan stopped the exploitation in 1985, but only in 2000 did the underground water level decrease begin stopping.
The underground water exploitation has been banned in Can Tho City. However, the ban needs to be applied in other localities as well.
However, once Mekong Delta cannot exploit underground water, it would lack clean water for daily use and production.
Vinh said: “We have to store water on the surface water layer in many ways. People have to store water in rainy season for use in dry season."