Simulating the effects of model parameters on stagnation points position during seawater intrusion

Several works have been performed in order to understand seawater intrusion by simulating the Henry problem. Investigations were implemented by simulating the effect of many parameters (fractured aquifer, dispersion and diffusion, geochemical reactions, heterogeneity, anisotropy, boundary conditions) on the flow and transport. This paper focus on the concept of the "stagnation point," and this concept plays an important role in modeling, management and characterization of coastal aquifer. A total of forty-eight simulations, including the base case, were made to explore the effect of molecular diffusion coefficient, dispersivity, and seawater density on the position of the stagnation point. It was found that the increase of the molecular diffusion coefficient or the dispersivity leads to a downward displacement of the stagnation to the aquifer bottom and the lowest point position is reached for a Pe value of 0.35. For the seawater density effect, numerical results predict a nonlinear behavior of the stagnation point position, where the downward displacement is detected only for a ρ_s ranging from 1025 to 1045 kg/m³.