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- Land subsidence due to groundwater exploitation in Vietnam
Land subsidence due to groundwater exploitation in Vietnam
Vietnam
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5 months agoProblems
Land subsidence due to groundwater exploitation in Vietnam
The overexploitation of groundwater in Vietnam’s Cuu Long (Mekong) Delta has contributed to severe land subsidence, which could lead to devastating consequences if the practice continues, experts have said. The delta, the country’s largest rice, fruit and seafood producer, is facing a land subsidence rate of 1cm per year, with some areas reaching a rate of 5.7cm, according to the Ministry of Natural Resources and Environment. Speaking at a seminar held in Can Tho, Tran Quang Khai of the Ho Chi Minh City University of Technology’s Water Management and Climate Change Centre, said that if Can Tho continued exploiting groundwater, most areas would become lower than sea level by 2100. Flooding and high tides would also become more severe, he said. Construction projects in Can Tho have also worsened land subsidence. Khai said: “The delta exploits two million cubic meters of groundwater a day, according to reports, but the reports do not include all household bore wells, so the volume is higher.” The main causes for subsidence are reduced sediment supply due to upstream dams, river sand mining, and groundwater exploitation. Nguyen Huu Thien, an independent expert on Mekong Delta ecology, said the cost of using surface water was higher than that of groundwater. He said the delta should develop zoning of areas where groundwater exploitation should be restricted. The Vietnamese government has recognized the severity of land subsidence and its impacts on agriculture, infrastructure, and communities. Efforts have been made to regulate groundwater extraction, promote sustainable water management, and implement land-use planning measures. However, challenges persist due to the complex interplay of natural and anthropogenic factors.
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Timelines
2020
December 11
Director of the IT Center of the Department of Natural Resources and Environment Bui Hong Son revealed at a seminar about rapid land subsidence in HCM City that according to the Ministry of Natural Resources and Environment, the city has had a subsidence rate of 4 centimeters; worse, even some places with 6-7 centimeters annually. Rapid land subsidence not only destabilizes the city infrastructure but also increases the risk of flooding, especially in the face of abrupt rainstorms, excessive rainfall and high tide levels. He pointed out that weak land, heavy traffic loads and groundwater exploitation are culprits of the problem.
2019
Since 2015 Tho City has had the highest rate of land subsidence, with more than 5cm in most areas.
2010
Since 2006 subsidence rates across the Delta have been measured by interferometric synthetic aperture radar (InSAR) analysis using 78 ALOS PALSAR interferograms. InSAR-based subsidence rates are 1) consistent with compaction-based rates calculated at monitoring wells, and 2) ∼1–4 cm yr−1 over large (1000s of km2) regions.
1975
After the reunification of North and South Vietnam, the country experienced rapid urbanization and industrialization. This period marked a substantial increase in the demand for water resources, leading to the widespread drilling of wells for groundwater extraction.
1955
The Vietnam War (1955-1975) brought significant changes to the landscape. Bombings and defoliation campaigns during the war may have had localized impacts on the land, but the widespread land subsidence issues became more evident in the post-war period.