REPORT OF INVESTIGATIONS No. 42


The average field coefficients of permeability (Pf) table 10) were
averaged for each area and then multiplied by the approximate
thickness of the aquifer (1,000 feet) to estimate the coefficient of
transmissibility (Te) for each representative area. The data were
analyzed for (1) the Davenport-Horse Creek area east of the Lake
Wales Ridge; (2) the eastern area, which includes the general area
between State Highway 33 and U.S. Highway 27; (3) the
northwestern area, which includes the area west of State Highway
33 and north of the Withlacoochee River; (4) the southwestern
area, which includes the area west of State Highway 33 and south
of the Withlacoochee River; and (5) the Dade City area west of the
Withlacoochee River. The results of the computations (expressed
to the nearest hundred thousand gpd/ft) are presented in table 11.
Computations of ground-water movement into or out of the area
used in the water-budget analysis were based on the estimated
coefficients of transmissibility shown in table 11.

 TABLE 11. Estimates of transmissibility
 T,,
 Area (gpd/ft)

 1. Davenport-Horse Creek 200,000
 2. Eastern 300,000
 3. Northwestern 500,000
 4. Southwestern 600,000
 5. Dade City 1,200,000

 Barrier boundaries caused variations in the values of T in the
 vicinity of the Lake Wales Ridge. Observation wells 815-139-2 and
 815-140-1 were used to observe the effects of drawdown and
 recovery caused by pumping well 814-139-5. Water level measure-
 ments were also made in the pumped well. The data were analyzed
 by the Theis method (1935), the family of leaky aquifer curves by
 Cooper (1936), and the Jacob method (1950). The data defined
 three curves, figure 39, with T values of 680,000 gpd/ft and
 1,150,000 gpd/ft, for the observation wells and 120,000 gpd/ft for
 the pumped well. The wide variation in T probably indicates that
 the basic assumptions prerequisite for the analysis of the data do
 not apply and is probably caused by heterogeneity of the aquifer
 and existence of a barrier boundary. The test site is in a faulted
 area (see fig. 8, C-C'). Figure 40 shows the location of the wells
 with respect to sand-filled fractures in the underlying lime-
 stone along the Lake Wales Ridge. The variation in T values
 is probably caused by sand-filled fractures which act as barriers