FLORIDA GEOLOGICAL SURVEY


Beach, Pensacola Beach, and the western two-thirds of Santa Rosa
Island.
 Ihe artesian pressure head of water from the Floridan aquifer ranges
from about 140 feet above sea level in northern Santa Rosa County (well
059-658-1) to about 55 feet above sea level in southern Santa Rosa
County (well 022-652-1). Therefore, the artesian pressure head in the
Floridan aquifer would be greater than the water table in the sand-and-
gravel aquifer at most of the low to moderate land elevations in the two
counties. The water in the Floridan aquifer would have a potential up-
ward flow. The water level in the sand-and-gravel aquifer would stand
above the artesian pressure head of the Floridan aquifer in the higher
land elevations of the area and would have a potential downward flow.

 FLUCTUATION OF THE WATER LEVEL
 Water-level records show that the water surface is not stationary but
fluctuates almost continuously. Water-level fluctuations result from vari-
ations in recharge and discharge. Discharge is from evaporation and
transpiration, seepage, and pumping. Recharge is from rainfall and
seepage from other aquifers. Long-term periodic measurements of water
levels are used to determine significant changes in the water in storage,
to correlate water levels and rainfall, and to show the influence of pump-
ing on the water level. Long-term records are needed to distinguish
between short-term fluctuations and progressive trends.
 Over most of the area, changes in the water level correlate in general
 with rainfall. In the heavily pumped areas, water levels reflect both the
 influence of the pumping and the rainfall.
 Figure 35 compares changes in the artesian pressure head in a well
 drilled into the Floridan aquifer with changes of the water level in a
 well drilled into the sand-and-gravel aquifer. Well 037-645-1 is at Aux-
 iliary Field 6, located 18 miles east of Milton, in Okaloosa County. This
 well is 690 feet deep and obtains water from the upper limestone of the
 Floridan aquifer from 527 to 690 feet below land surface. Well 032-648-1,
 15 miles southeast of Milton, is 197 feet deep and obtains water from the
 sand-and gravel aquifer from about 140 to 197 feet below land surface.
 Well 037-645-1 is a representative well for this area. It taps the upper
 limestone of the Floridan aquifer and has a long-term record. The hy-
 drograph is included to show the relation between artesian pressure
 changes and the use of water, to illustrate the fluctuations in artesian
 pressure in the upper limestone of the Floridan aquifer, and to compare
 these fluctuations with those in the sand-and-gravel aquifer.