Mechanism of sanility intrusion and temporal distribution of freshwater in the Dinh An estuary, Vietnamese Mekong delta

Tóm tắt

The Vietnamese Mekong Delta (VMD), responsible for over half of Vietnam’s rice production and most of its aquaculture and fruit yields, is facing freshwater shortages due to intensified salinity intrusion (SI) and climate change impacts. This study integrates field measurements and MIKE 3D numerical modelling to analyze the spatial and temporal dynamics of salinity intrusion in the Dinh An branch of the Hau River. Results show that peak salinity concentration (Smax) typically occurs near the bottom, lagging 1–2 hours behind maximum water level during tidal cycles and 4-6 days in fortnightly tidal cycle during the neap–spring transition. The Dinh An estuary exhibits partial mixing with moderate stratification, with freshwater availability extending approximately 30 km inland during the dry season. The research results provide an important scientific basis for optimizing sluice gate operations to manage freshwater intake. Keywords: Salinity intrusion, Mekong estuaries, tidal regime, mixing and stratification