Louisiana hydrologic atlas map no. 2: Areal extent of freshwater in major aquifers of Louisiana

The areal availability of freshwater (cl content < 250 mg/L) in 14 major aquifers in Louisiana was investigated. The depth of occurrence of fresh groundwater in Louisiana is variable. The aquifers were mapped to show their areal extent from the outcrop or subcrop to the downdip limit of freshwater. Water in each aquifer becomes saline downdip; but in most areas an overlying (younger) aquifer contains freshwater. None of the major aquifer contains freshwater in northern Louisiana where the Vicksburg and Jackson groups crop out and the underlying Cockfield aquifer (Cockfield Formation) contains saline water.