Transport of contaminants in aquifers has received considerable attention over the past few years. In coastal aquifers, a dispersion zone between saline water and fresh water exists where the flow of water and transport of salt ions are coupled. The flow pattern of two miscible fluids of different unit weights is characterized by the cyclic flow at the shore boundary. The width of the dispersion zone may be considerable, with the sharp interface assumption leading to erroneous results. A finite element model was applied to two prepublished problems for purposes of obtaining a better understanding of the saline water intrusion phenomenon. The effect of lowering the piezometric head due to excessive pumping was investigated. Physical parameters were extracted from the studies conducted by Kawatani and Rouve and Stoessinger, and comparison with their results was made.