Impacts of anthropogenic stressors and climate change on hydrology regime in the Vietnamese Mekong Delta

Abstract

Purpose – The Vietnamese Mekong Delta (VMD), a vital agricultural region supporting millions, faces severe environmental threats from interacting anthropogenic pressures and climate change, profoundly altering its hydrology. A comprehensive, quantitative understanding of recent water level changes is lacking. This study aims to identify and quantify changes in annual flood peaks and key tidal water level characteristics (1980–2024), analyzing the combined drivers. Design/methodology/approach – This paper analyzed long-term (1980–2024) daily/hourly water level records from strategic hydrometric stations. Time series analysis, including low-pass filtering and Mann–Kendall/Sen’s slope tests, identified significant changes in annual flood peaks, mean water levels (MWLs) and tidal range (TR). Findings – Analysis reveals significant upstream flood peak decline (especially post-2010s, linked to hydropower). MWL decreased upstream post-2000 but rose substantially mid-delta/coastally, amplified beyond regional relative sea level rise by local factors. Most stations show marked lower low water decreases alongside significant TR increases, indicating enhanced tidal propagation and amplification, more pronounced along the Tien River than the Hau River. Originality/value – This paper offers a quantitative, spatiotemporal assessment connecting flood and tidal regime changes to the interplay of multiple drivers during accelerating environmental change. It highlights escalating risks—reduced freshwater availability, increased tidal inundation, heightened salinity intrusion—providing crucial insights for developing robust water resource management and climate adaptation strategies essential for the VMD’s sustainability.