REPORT OF INVESTIGATIONS NO. 42


bicarbonate. Additional ground-water inflow in this reach of the
river is indicated. The chemical characteristics of this inflow
indicate that it was derived from the Floridan aquifer.
 Gator Hole Slough, a tributary to the Withlacoochee River
downstream from Dade City, was sampled at high flow. The water
was low in mineral content and contained sodium and chloride as
the principal dissolved mineral constituents. The color was 180
units.
 Data were collected during the period of low flow (May 23-25,
1961) to determine the quantity and mineral content of the
ground-water inflow in the reach of the Withlacoochee River
between the stations near Lacoochee and Trilby (see fig. 11). The
mineral content of the ground-water inflow from the Floridan
aquifer into this reach of the Withlacoochee River was computed
using the load equation (Hem, 1959):
 QIC, + Q2C2 Q3C3
 where, Q is the discharge in cfs
 C is the mineral content in ppm
 QiCi is the instantaneous load near Lacoochee
 Q2C2 is the instantaneous load between data-
 Collection stations
 QsC3 is the instantaneous load at Trilby
The inflow (Q2) was determined to be 12.2 cfs by subtracting the
discharge near Lacoochee from that at Trilby. The mineral content
(C2) of the inflow was then computed to be 260 ppm which is
approximately equal to that of water in the Floridan aquifer in
this area.
 The mineral content of water in the Withlacoochee River at
Croom (station 44) was less than that at Trilby (station 42) or
that at Rerdell (station 43). The difference between the sum of
the discharges at Trilby and Rerdell and that at Croom on May 25,
1961, was 38.9 cfs (see fig. 11). Based on the load equation, the
mineral content of the inflows between the stations would be 148
ppm. Similar computations of data during other periods show
the mineral content of the ground-water inflows in this area to
range from 148 to 174 ppm. The computed mineral content indicates
that the inflow between stations was probably a composite of
surface water and ground-water inflows.
 The mineral content of the water in the Little Withlacoochee
River is shown in figure 13f. The color was usually above 100 units
during periods of high flow. The principal mineral constituents
during periods of low flow were calcium-and bicarbonate, the water