The fresh water lens in a barrier beach.
Date of Original Version
Oceanic landmasses, under natural conditions commonly develop a body of fresh groundwater. This freshwater body assumes the form of a lens floating on the underlying seawater, and is usually thickest at the central part of the landmass tapering to a thin edge at the shore margins. With certain unique exceptions as will be described herein the flow moves from the thickest part of the lens outward and upward to the shoreline. The extent of a freshwater lens depends primarily on landmass width, permeability, rainfall, and tidal range. As a part of a general study of the freshwater lens phenomena, a field investigation was made at East Beach, the largest of the Rhode Island barrier beaches.(from paper)
Urish, D. W.. "The fresh water lens in a barrier beach.." , (1977). https://digitalcommons.uri.edu/cve_facpubs/363