Assessing Impacts of Sea Level Rise and Sea Dike Construction on Salinity Regime in Can Gio Bay, South Vietnam

Abstract

To protect Ho Chi Minh City (HCMC) from submergence due to the ongoing rapid sea level rise (SLR), the Vietnamese government have proposed the construction of a sea dike in Can Gio Bay. Can Gio Bay will be closed to regulate the storage and to control water levels in the drainage and sewer systems of HCMC. This could significantly impact the salinity distribution in the Bay and affect its mangrove forest. In this study, a set of scenarios will be analyzed using two-dimensional hydrodynamic and convective-dispersive models to assess the effects of SLR and the construction of a sea dike on salinity distribution in the Bay. The results reveal that the salinity in most areas of the Bay tended to increase positively with the SLR. The sea dikes significantly reduced seawater intrusion into half of the upstream area of the Bay. Considering the influence of SLR and the construction of a sea dike, the sea dike could result in the reduction of salinity. Furthermore, if the sea dike was operated for a long time, half of the Bay area would become freshwater, which would lead to adverse effects on the mangrove forest.