FLORIDA GEOLOGICAL SURVEY


 Most of the nonartesian ground water in the Green Swamp area
is discharged by evapotranspiration because the water table is
relatively close to the surface and surface drainage is poor.
Evapotranspiration losses are least in the sandy ridge areas that
rim the Green Swamp because the water table is farther beneath
the ground than in the interior.
 Ground water percolates downward from the nonartesian aquifer
to recharge the underlying Floridan aquifer because the water table
is usually at a higher elevation than the piezometric surface
as shown by the hydrographs in figures 23-29 and the aquiclude
(undifferentiated clay) between the aquifers is relatively thin (see
fig. 8) and permeable. The coincidence of areas of high water table
and of high piezometric head is evidence of leakage. The amount
of ground water that percolates downward is equal to the net
outflow of artesian water from the underlying Floridan aquifer.
The quantity of ground water leaving the Polk piezometric high
in the Green Swamp area, hence leakage from the nonartesian
aquifer, is presented in the table on page 116.
 Nonartesian ground water moves laterally to contribute to the
surface runoff from the area. The direction of movement is
generally governed by the topography. Therefore, ground-water
divides in the nonartesian aquifer closely coincide with surface
drainage divides shown in figure 5 except along the eastern
boundary of the area where some nonartesian ground water flows
laterally beneath the Lake Wales Ridge eastward to the Kissimmee
River basin. The quantity of nonartesian ground water leaving the
Green Swamp area by lateral seepage beneath the ridge was
estimated to be insignificant in the water-budget analysis.
 Fluctuations of the water table were recorded in several shallow
wells and water-table lakes in and near the southern and eastern
parts of the area, shown in figures 23-29. No data were obtained in
the western part because the nonartesian aquifer is thin or absent.
The hydrographs of wells in the nonartesian aquifer are presented
with hydrographs of wells in the secondary artesian or Floridan
aquifers to show the hydraulic relation between aquifers and the
potential movement of water in a vertical direction.
 No long-term records of water-table fluctuations are available
within the Green Swamp area. However, records of water levels
in a well located southeast of the Green Swamp area (810-136-2)
show that the highest and lowest water levels since 1948 occurred
during the period of investigation.