REPORT-.OF INVESTIGATIONS NO. 75


the Peninsula well, and the relation between tidal effects at the shoreline and tidal efficiency that was proposed by Van Der Kamp (1972).

      On the basis of Van Der Kanmp's theory of tidal efficiency at the shoreline, the tidal fluctuation (ho~) in the Boulder Zone at the shoreline was calculated from tidal fluctuations in Biscayne Bay at Coconut Grove during November 25 - 27, 1970 and February 5 - 8, 1971. The tidal fluctuation in Biscayne Bay at Coconut Grove was 1.86 feet on the average; therefore, the fluctuation in a well tapping the Boulder Zone at the shoreline (hc,) would be 0.28 foot on the premise that the tidal efficiency at the shoreline is about half the loading efficiency (0.30).

      The distance (x) from the shoreline to the Peninsula well is 6 miles. The analysis of water-level fluctuations in the well and tide fluctuations at Coconut Grove indicated. that the ocean tide component lagged the well component by 3/4 hour (21.*70) in addition to the time required for the tidal fluctuation to travel from the shoreline through the aquifer to the well, which is equivalent to tin equation 5.

      By assuming values of ti it was possible to calculate phase and amplitude relationships and approximate diffusivity values using the time-lag and stage-ratio equations. The substitution or iterative process continued until a diffusivity value was obtained that satisfied both equations and the phase-amplitude relationship in figure 9. The results of the iterative process yielded a diffusivity of 2.1 x 10 11 ft2/day .


         SPECIFIC STORAGE AND HYDRAULIC CONDUCTIVITY

      The specific storage, Ss is the volume of water released from or taken into storage per unit volume of aquifer per unit change in head. Hydraulic conductivity, K, is the volume of water that will move in a unit time under a unit hydraulic gradient through a unit area of aquifer measured at right arigies to the direction of flow.

      The specific storage was calculated for porosities ranging from 10 to 90 percent by the following equation (Bredehoeft, 1967,1p. 3083; Carr and Van Der Kamp, 1969, p. 1023):


                     S5 s    0    j37(9)
                                 BE