Numerical Simulation of Saltwater Intrusion in Coastal Aquifers

The modeling of groundwater in costal aquifers is an important and difficult issue in water resources. The primary difficulty resides in efficient and accurate simulation of the movement of the saltwater front. This thesis is devoted to the sharp interface numerical study of one and two dimensional of seawater intrusion into coastal aquifers. The Finite Volume method is adopted here to solve the set of simultaneous diffusion differential equations describing the motion of saltwater and freshwater separated by a sharp interface. These diffusion equations are based on the Dupuit approximation and are obtained from integration over the vertical dimension. The one dimensional Finite Volume model is first being validated using academic test case studies with known close from solutions. The second purpose of this study is to compare two dimensional numerical methods, Finite Volume method and Sharp model based on Finite Difference method when applied to a Llobregat aquifer, in Barcelona, Spain. Both methods are using the same mathematical formulation for the sharp interface. The comparison between both methods indicates that Finite Volume method provides predictions closer to the observed results