FLORIDA GEOLOGICAL SURVEY


the basin. The divides do not coincide along the eastern boundary
of the Green Swamp area because little or no water reaches the
water table beneath the ridge. During dry periods, the water-table
divide is located about 3 miles west of U. S. Highway 27, and
nonartesian ground water moves laterally beneath the Lake Wales
Ridge from the St. Johns River basin to the Kissimmee River basin.
During seasonally wet periods, however, there is sufficient
downward seepage through the ridge sediments to build up a
temporary ground-water divide beneath the Lake Wales Ridge.
This low wet-season divide recedes rapidly and the hydraulic
gradient is resumed from the Green Swamp eastward to the chain
of lakes, swamps, and streams which lie at the base of the eastern
side of the Lake Wales Ridge. Ground water moves eastward in
the nonartesian aquifer beneath the ridge along a 25-mile stretch
from Haines City almost to Clermont. Data from wells drilled on
each side of the ridge indicate that the nonartesian aquifer is about
100 feet thick. Hydraulic gradients to the east in the nonartesian
aquifer, measured across the ridge at 10 locations, averaged 6.6
feet per mile. The coefficient of permeability of the nonartesian
aquifer beneath the ridge probably ranges from 20 to 180 gpd/ft2
on the basis of data shown in table 8. Using an assumed coefficient
of 200 gpd ft.', the computed ground-water discharge from the
nonartesian aquifer in the eastern area was about 5 cfs in 1961.
This discharge from the 208 square-mile area is equivalent to 0.3
inch, an insignificant budget factor.
 The ground-water outflow from the basins through the Floridan
aquifer was computed as follows: (1) the drainage basin map
(fig. 5) was overlain by the piezometric maps and streamlines were
drawn to intersect and subdivide the boundary of each selected
basin into numerous flow sections, shown in figure 53; (2) the
hydraulic gradient (I), computed from the map, was multiplied by
the length of the flow section, also scaled from the map, to obtain
a flow factor for each flow section; (3) the discharge through each
section was computed by multiplying the flow factor by the
coefficient of transmissibility; (4) the sum of discharges through
all flow sections around the boundary represents the net ground-
water discharge from the basin. The total discharge was computed
in units of million gallons per day (mgd) and converted to cubic
feet per second (cfs); (5) ground-water discharge from a drainage
basin was expressed in terms of outflow in inches for the basin so
that it could be compared readily with rainfall and surface runoff.


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