A severe landslide along a bank of the Tien River in Thanh Binh district in the Mekong Delta province of Dong Thap. (Photo: VNA) Speakingat the online event, Nguyen Huu Thien, an expert on Mekong Delta ecology,said that land subsidence is a threat to many of the world’s deltas,especially the Mekong Delta in Vietnam.
Theoverexploitation of groundwater in the region has contributed to severeland subsidence and will lead to devastating consequences if thepractice continues, according to the expert.
“Itis essential to support policymakers in exploring suitable, consistentstrategies for mitigating subsidence in a participatory manner.”
Inrecent years, data has become available showing the rate at which the MekongDelta is subsiding, according to the Ministry of Natural Resources andEnvironment.
Thien,who is deputy head of the Governance of Land Subsidence and GroundwaterManagement for the Mekong Delta project, said it was paramount to identifyalternative water sources, the value of water sources, and the link betweengroundwater extraction and land subsidence.
Begun inJanuary 2020 and completed last month, the project aimed to enhance thecapabilities of individuals and organisations to develop sustainable strategiesfor dealing with the problems.
Underthe project, a new integrated delta model linked surface water,groundwater and geo-mechanical models in order to analyse the interrelatedcharacter of groundwater extraction, subsidence levels and saltwater intrusion.
Theintegrated model was applied to quantify the effects of water managementstrategies in the Mekong Delta.
Strategieswere developed by simulating and demonstrating the effects of developmentscenarios and policy recommendations as mentioned in the Mekong Delta Plan in2013.
Fourcase-study fact sheets of Can Tho City and Ben Tre, Soc Trang, and Kien Giangprovinces have been developed. The four provinces all face majorproblems concerning land subsidence and groundwater extraction depending onlocation-specific characteristics.
Thekey challenges, needs and opportunities for governance of landsubsidence and groundwater management were identified with the support ofseveral workshops, close collaboration with Cần Thơ University, and key actorsin the Mekong Delta.
TheMinistry of Natural Resources and Environment has issued a decree thatrequires zoning plans to cope with land subsidence. Each province is at adifferent stage of implementing the decree.
Thefour pilot provinces indicated common challenges: a scarcity of availabledata to be used in decision-making, a lack of a proper monitoring network,insufficient financial incentives (pricing), a lack of spatial planning, littleregional coordination, limited regulations for groundwater extraction, andscarce financial and technical capacities.
Theproject has contributed to good water governance, closing the disconnectbetween local communities and decision-makers. At a later stage, acollaborative learning process can start, creating flexibility in the setgoals.
Projectchallenges
Whilefurther research is necessary to identify hotspots in the Mekong Delta,experts said it was clear from the evidence that land subsidence induced bygroundwater extractions could lead to increased flood vulnerability and damageto infrastructure and buildings.
Groundwaterextractions are augmented by changes in weather extremes and climate changeleading to increased saltwater intrusion and droughts, intensifying issues inthe Mekong Delta, according to the experts.
Groundwaterextraction and resulting land subsidence is a gradual process, but vitaltipping points should be avoided. These could have financial implications aswell as affect a wide variety of livelihoods.
Vietnamand the Netherlands signed the Strategic Partnership Arrangement on ClimateAdaptation and Water Management under the Mekong Delta Plan in 2013.
Sincethen, the two countries and international stakeholders have collaborated totranslate the plan’s vision into concrete policy ambitions.
TheMekong Delta, the country’s largest rice, fruit and seafood producer, is facinga land subsidence rate of 1 cm per year, with some areas reaching a rate of 5.7cm, according to the Ministry of Natural Resources and Environment.
CanTho City has the highest rate of land subsidence, with more than 5 cm inmost areas during the 2015 - 19 period.
Therapidly increasing population and economic development are driving a rapidincrease in water consumption. The associated extraction of groundwater fordrinking water, agriculture and fisheries is to blame for the dramatic landsubsidence in the low-lying region./.
VNA
