100 FLORIDA GEOLOGICAL SURVEY

pressure and wells 5 to 6 inches in diameter drilled at lower elevations
yield from 50 to several hundred gallons per minute by natural flow.
 A study of electric logs indicates that the water in the upper lime-
stone of the Floridan aquifer is fresh except in the southwestern part of
Santa Rosa County and the southern half of Escambia County. The logs
also indicate that the water in the lower limestone of the Floridan aqui-
fer is fresh in the northern part of both counties and salty in the southern
part.
 Any proposed user of water from the upper limestone of the Floridan
aquifer in southeastern Santa Rosa County might expect a gradual de-
cline of the artesian pressure head. The decline of the artesian pressure
head is presently centered around Fort Walton Beach. At Holley and
Navarre, the artesian pressure head declined about 20 feet from 1942 to
1961. The same rate of decline of about one foot per year is expected
to continue in the Holley-Navarre area. This decline means that in the
future some wells will stop flowing and the yield by natural flow from
other wells will decrease somewhat.