Practical paths to halt elevation loss in Vietnamese Mekong Delta

• Elevation loss in the VMD threatens people due to four key environmental pressures. • Managing global and transboundary pressures requires cooperation and strategic action. • Local pressures such as sand mining and groundwater extraction cause a loss of 2-6 cm/yr. • Practically stricter policies are needed to ensure the VMD's sustainability and resilience. Despite considering as one of the world's most vulnerable delta regions, the local pressures and actionable solutions to address elevation loss in the Vietnamese Mekong Delta (VMD) remain insufficiently studied. The VMD—39 000 km² that feeds 18 million people—is sinking because four pressures act in concert: upstream dams have already cut sediment delivery by 70 %–83 % (projected 96 % if all planned projects proceed), mean sea level is rising 1.5–2 cm/yr, river-bed sand mining now removes about 3 Mm³/yr and deepens channels by up to 15 cm/yr, and groundwater withdrawals of approximately 2.5 Mm³/day have accelerated land-surface subsidence from smaller than 3 cm/yr in 2006–2010 to peaks of 5–6 cm/yr today. Scenario modelling shows that halving pumping would stabilize aquifer heads and cut subsidence by about 50 % within a decade, while provincial sand-quota cuts of 30 %–50 % would slow bed incision and ease salinity intrusion, reducing the irrigation deficits that drive further pumping. While the large-scale causes of subsidence (dams, sea level rise, sand mining, groundwater extraction) are well recognized, actionable, local-level management solutions to immediately slow subsidence and salinity intrusion—independent of slow international negotiations—have been underexplored and under-implemented. Because dam and climate remedies depend on slow transboundary negotiations, we argue for a concentric policy strategy that first tightens sand-mining licenses, enforces tiered groundwater tariffs, and scales up rain- and surface-water alternatives, buying time for longer-term basin and climate agreements. These locally actionable measures can measurably bend the subsidence curve and offer a transferable template for sustaining deltas worldwide.