Drought-induced land subsidence in the Mekong Delta, Vietnam: Insights from SAR interferometry

This paper shows, based on subsidence time series from SAR Interferometry, that severe droughts can significantly intensify the subsidence in the Mekong Delta. The researchers measured a subsidence of up to 7 cm in few months during a drought in 2020, which was compensated by uplift in the following rainy season in some but not all regions.

The magnitude of the drought-induced subsidence was spatially correlated with specific surface water management and land use zones, with the largest impact in rain-fed, rice growing regions. The authors argue that the uncompensated surface drop in two regions, reaching up to 3.5 cm, was caused by inelastic deformation. Such irreversible subsidence has a major impact on the delta's future elevation, especially under the assumption that the frequency of droughts will increase under climate change and an increasing water demand.