Investigation of sea level rise effect on saltwater intrusion in an unconfined coastal aquifer using sharp-interface approach

Abstract

A numerical sharp-interface model is developed to predict saltwater intrusion (SWI) into an unconfined coastal aquifer due to sea level rise (SLR). The model is applied to a conceptual field-scale aquifer to explore the sensitivity of the intrusion mechanism to various involved parameters. In all of the simulations, appropriate SLR rate has been applied to the sharp-interface model. The 90 years unsteady results showed that changes in hydraulic conductivity, rainfall recharge and freshwater inflow have significant effect on intrusion but the model is not very sensitive to different values of porous media porosity and specific yield. Afterward, the seaside saltwater head is raised and the toe of new time dependent salt wedge is determined. The results demonstrated that the SLR leads to more SWI. This excess intrusion is not very clear when SLR rate is low (e.g., 0.2 mm/year) but saltwater intrudes significantly further when the rate gets the higher values (e.g., 8 mm/year).