1. Louisiana ground-water map no. 7 : potentiometric surface, 1991, and water-level changes, 1969-91, of the Chicot equivalent aquifer system in southeastern Louisiana Yale Public content 1995. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; Copies may be purchased from Open-File Reports Section. English. Public. Louisiana.