Freshwater/Saltwater Interface on Long Island, New York

Freshwater/Saltwater Interface on Long Island, New York: The figure above shows a generalized schematic of the boundary between fresh and saline groundwater, referred to as the "freshwater/saltwater interface".  When too much groundwater is removed from the aquifer system, the freshwater/saltwater interface can move landward by a process referred to as "saltwater intrusion".  If pumping wells are near this boundary, they may begin to pump saltwater, thereby limiting the use of the well for drinking water. (Public domain)