 Meteoric freshwaters can discharge along confined and unconfined aquifers into the sea or the oppositional process of seawater intruding into groundwater charged aquifers can take place.The flow of both fresh and sea water is primarily controlled by the hydraulic gradients between land and sea and differences in the densities between both waters and the permeabilities of the sediments.According to Drabbe and Badon-Ghijben (1888) and Herzberg (1901) the thickness of a freshwater lens below sea level (z) corresponds with the thickness of the freshwater level above sea level (h) as