Salinity dynamics under sea level rise scenarios in the Red – Thai Binh River delta, Vietnam

Salinity dynamics in the Red – Thai Binh River delta in Vietnam is now becoming a highly concerning issue, for its freshwater is an essential supply for sanitation, agriculture and industry in the North of Vietnam. This study investigates current and future river hydrodynamics and seawater intrusion under sea level rise scenarios, by using 1D model MIKE 11. Simulations indicate an increase trend in maximum salinity concentrations in each river branch from the current condition to 2100 for two sea level rise scenarios (RCP4.5 and RCP8.5). A noticeable intrusion of salinity is expected to occur in the main stream of Red River, while Thai Binh River systems should be affected by a less intense, but still considerable, impact. Two salinity thresholds 1 ‰ and 4 ‰ are also considered for agriculture purposes; their assessment shows a significant salinity increase from baseline year to 2100 RCP8.5.