Thickness of the upper confining unit of the gray limestone aquifer, southern Florida, USGS WRIR 99-4213 figure 22

The upper confining unit of the gray limestone aquifer ranges from 20 to 60 ft in thickness in most of the study area, but is absent to the west and southwest in much of Collier County and most of Monroe County. The map shows the thickness of the upper confining unit in feet. The contour interval is 50 feet.

The purpose of this report is to evaluate the hydrogeologic framework, hydraulic properties, and ground-water flow of the gray limestone aquifer in southern Florida. The report also emphasizes the geologic framework (stratigraphy and structure) and the hydrogeologic framework (aquifers and confining and semiconfining units) above and below the gray limestone aquifer.