BUREAU OF GEOLOGY
T = transmissivity
S = storeage coefficient
r = period of fluctuation
The time required for a given oceanic tidal fluctuation to travel through an artesian aquifer from the shoreline to an inland well (Ferris, 1962, p. 134, equation 67) can be written
t1 x. T (5)
2 rrT
where t1 = the time lag at distance x from the shoreline.
HYDRAULIC DIFFUSIVITY
Hydraulic diffusivity is defined as the conductivity of the aquifer when the unit volume of water moving is that involved in changing the head a unit amount in a unit volume of aquifer (Lohman, 1972, p. 8). As stated -earlier it is essentially the ratio of transmissivity (T) to the storage coefficient (S) or the ratio of hydraulic conductivity (K) to specific storage (Ss).
Hydraulic diffusivity = T% = K/S s (6)
Equations 4 and 5, the stage-ratio and time-lag equations of Ferris, were rearranged and solved for diffusivity (T/S):
T/S = K = x2 7r (7)
S s r (In h0)2
w
T/S K -x2 T (8)
s 4 7r t2
The hydraulic diffusivity of the Boulder Zone was computed by a method using equations 7 and 8, trigonometric equations suggested by Cooper to separate ocean-tide and earth-tide components of the water-level fluctuations in