14 FLORIDA GEOLOGICAL SURVEY
aquifers by leaking downward from the water-table aquifer, supplementing the upward leakage of water from the Floridan aquifer.
Where wells are open to more than one aquifer, water moves up or down the well bore from the aquifer having the greatest pressure into the aquifer having the least pressure. Of the three wells at the water plant for which record of casing and depth are available, two (plant wells 2 and 3) are open to both the Floridan aquifer and the second artesian aquifer. Water from the Floridan aquifer, therefore, moves up the well bores of these two wells into the second artesian aquifer. Moreover, water from the second artesian aquifer moves into the first artesian aquifer through the 27 wells that are open to both the first and second artesian aquifers when these wells are not being pumped.
HYDRAULIC PROPERTIES
Three pumping tests were run to determine the hydraulic properties of the first and second artesian aquifers. The tests were made by pumping one well at a constant rate and observing the change of water level in one or more nearby observation wells.
While these tests were being made, water was supplied to the city from the wells farthest from those being tested. The wells that were supplying the city were pumped at a constant rate until the water levels in the wells to be used in the test had stabilized or until the change in the water levels was so slow that it could be extrapolated through the period of the test. Because pumping from wells outside the field could not be controlled, the tests were begun after about 6 p.m. and were continued until about 7 a.m. the following morning-a period when the withdrawals from private wells were at a minimum.
The pumping tests were conducted to determine three aquifer constants---the coefficient of transmissibility (T), the coefficient of storage (S), and the coefficient of leakage (P'/m'). The coefficient of transmissibility is a measure of the ease with which an aquifer transmits water and is defined as the quantity of water, in gallons per day, that will move through a vertical section of the aquifer 1 foot wide under a unit hydraulic gradient. The coefficient of storage is a measure of the capacity of the aquifer to store or release water and is defined as the volume of water released from or taken into storage per unit surface area of the aquifer per unit change in head. The coefficient of leakage is a measure of the ability of the confining bed to leak water. It is defined as the flow, in gallons per day, that will cross a square foot of the interface be-