Home Abstract Introduction Hydrogeology of S. Florida - Floridan Aquifer System > Hydrogeology at Alligator Alley Site   -  Surficial Aquifer System   -  Intermediate Aquifer System   -  Floridan Aquifer System Ground-Water Movement Subsurface Storage Summary and Conclusions References PDF Version

Hydrogeology of Southern Florida: Hydrogeology at the Alligator Alley Test Well Site

A 2,811-ft-deep test well (Well G-2296) was drilled in 1980 during this RASA study in the Everglades of southern Florida along Alligator Alley (Interstate 75) at a point between Naples and Fort Lauderdale (fig. 2, site 10). A steel casing 16-inches (in) in diameter was installed with cement grout from land surface to a depth of 895 ft, below which a nominal 8-in-diameter hole was drilled to a depth of 2,811 ft (fig. 8). A 2-in-diameter steel monitor tube with perforations from 811 to 816 ft was grouted with cement in the outer annulus. Hydraulic packers were used to isolate selected zones in the well to collect samples of ground water and measure water levels.

The well penetrated the surficial and intermediate aquifer systems and extended into the Floridan aquifer system (fig. 9). The surficial aquifer system is about 180 ft thick and is composed chiefly of sandy limestone of the Tamiami Formation of Pliocene age. Three artesian limestone aquifers and related confining beds are present in the intermediate aquifer system between 180 and 770 ft in Miocene deposits. The top of the Floridan aquifer system is at 770 ft. The Floridan is confined by the overlying Miocene deposits. About 67 percent of the total thickness of the Floridan aquifer system was penetrated by the well. The formations that make up the Floridan aquifer system (from shallowest to deepest) at the well site include the Suwannee and Ocala Limestones and the Avon Park and Oldsmar Formations. The Floridan aquifer system is composed of several water-bearing zones and associated confining units. The well did not penetrate the Cedar Keys Formation, which contains the lower confining unit of the aquifer system.