VietNamNet Bridge - Landslide and subsidence have occurred repeatedly on a large area in the southern most province of Ca Mau. Experts said the phenomenon was caused by drought, which has lasted for several months in southern Vietnam.

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Kids walk on the bed of a river in Tran Van Thoi District, Ca Mau.


In Tran Van Thoi District alone, up to 228 cases of landslides and subsidence have been reported recently, damaging many roads.

Nguyen Dong Khoi, Chairman of Khanh Binh Dong commune in Tran Van Thoi district, said the number of landslide and subsidence cases is on the rise. This has damaged the only road to the commune center.

Such incidents have occurred very often in the districts of Tran Van Thoi, U Minh and Thoi Binh. Hundreds of roads are cracked and landslides, hindering traffic. Some irrigation works were also affected.

In the districts of Dam Doi, Nam Can and Ngoc Hien, landslides are affecting 132 households living along the river.

Nguyen Long Hoai, Head of Ca Mau Irrigation Division, said that landslide tends to expand and the local authorities told people to quickly move to safe places if they see signs of landslide and subsidence.

According to the latest research by the Southern Region Geological Mapping Federation under the General Department of Geology and Minerals of Vietnam, Ca Mau peninsula is continuing to sink.

Dr. Do Van Linh, Deputy Head of the Southern Region Geological Mapping Federation, said the deepest subsidence in Ca Mau was measured 1.71 cm a year, while the average subsidence due to groundwater exploitation was about 0.35 cm a year.

There are three reasons for this situation: subsidence due to young sediment and water exploitation, and by tectonic movements. This trend will continue in the coming years.

 

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A house collapsed because of landslide.

 

Previously, studies of the Norwegian Geotechnical Institute (NGI) showed that Ca Mau is sharply subsiding. The subsidence speed measured was higher than the studies of the Southern Region Geological Mapping Federation.

According to NGI, Ca Mau may suffer from serious subsidence on the surface, as the result of surface water pumping activities of 109,096 wells with the total pumped water volume of 373,000 m3 a day.

If the exploited water volume is divided for the total area of Ca Mau province (approximately 4,350 km2), the speed of subsidence is 1.9 to 2.8 cm a year. If the area of Ca Mau province is 5,300 km2 instead of 4,350 km2, the subsidence rate is 1.56 to 2.30 cm a year.

NGI's research also pointed out, in 15 years (1998-2013), ground subsidence rate would be 30-80 cm and it is predicted that in the next 25 years, the rate of subsidence will increase to 90-150 cm and 210 cm in the next 50 years.

Le Ha