Groundwater Resources in the Mekong Delta: Current Status, Challenges, and Sustainable Approaches under Dual Impacts

Abstract

This review synthesizes recent evidence on groundwater security in Vietnam’s Mekong Delta under the twin pressures of climate change and sustained over-abstraction. Advancing prior work, we (i) integrate disparate findings into an extraction–subsidence–salinization systems frame and (ii) align post-2015 scientific evidence with the latest regulatory reforms to distill implementable pathways. Using a selective but transparent literature strategy focused on peer-reviewed studies (2015–2025) indexed in Scopus/Web of Science and authoritative governmental/international reports, we prioritized sources with explicit methods, georeferenced observations, and reported uncertainties; grey literature without methodological disclosure was screened out. The Delta’s multi-aquifer endowment is heavily stressed: recorded withdrawals from centralized wells are approximately 2.0 million m³ d⁻¹, groundwater heads decline by 0.3–0.5 m y⁻¹ across many localities, and land subsidence averages about 1.07 cm y⁻¹ with urban hotspots exceeding these values; earlier and deeper saltwater intrusion further jeopardizes domestic supply and agriculture. Water-quality risks—including widespread microbial contamination and geogenic arsenic above WHO guidelines—compound exposure. While recent legal instruments establish clearer mandates for restricted zones, licensing, and extraction charges, implementation is hindered by fragmented monitoring networks, limited metering of household wells, and transition costs for small users. We propose a four-pillar strategy: legally binding, risk-zoned extraction thresholds; phased substitution by interprovincial surface-water conveyance; managed aquifer recharge (e.g., riverbank filtration) in suitable formations; and digital metering coupled with economic instruments and integrated forecasting that co-simulates extraction, subsidence, and salinity. The review also identifies critical evidence gaps—household abstraction inventories, in-situ deformation–pumping linkages, and cost-effectiveness of recharge options—that should anchor near-term research. Collectively, these measures are necessary to arrest the subsidence–salinity feedback loop and restore groundwater resilience in the Mekong Delta.