RESEARCH· ·1970·

B222
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RELATION BE'l;'WEEN GROUND WATER AND SURFACE WATER
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Cooper and Rorabaugh ( 1966, p. 363) show that
approxiinately 65 percent of bank storage would remain
in the ground at 84 hours on the gradient curve
when the bank storage component alone is considered.
Tll.erefore, shaded area .Y (fig. 5iv) represents the
entire volume of bank storage, but it is composed of a
mixture of bank storage (about 35 percent) and the
combination of aquifer discharge and local recharge
(about 65 percent) .
Even though the 1nixture may continue to discharge
for a time equal to several flood periods, the bankstorage
volume has been accounted for at time c so that
all volmne of discharge after that Inay be considered
the voh1me of ground-water discharge, or base flo'Y·
The resulting curves for peaks 1 and 2 are shown ih
figure 6.
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