REPORT OF INVESTIGATIONS NO. 42


cfs in September 1960. Little Creek serves as an outlet for much of
the flood drainage from the upper Withlacoochee River basin.

 CHEMICAL CHARACTERISTICS OF SURFACE WATER

 Waters of Big and Little Creeks have chemical characteristics
similar to those of the Withlacoochee River upstream from State
Highway 33 in that they have very low mineral content and are
highly colored. Figure 16a shows that the mineral content of
water in Big Creek ranges from 19 to 61 ppm. Figure 16b shows
that the mineral content of water in Little Creek ranges from 18
to 31 ppm. Color of water in Big Creek ranges from 65 to 240
units and that of Little Creek ranges from 150 to 300 units. Both
streams usually contain sodium and chloride as their principal
dissolved mineral constituents.
 Waters of the two streams differ in chemical characteristics in
that water of Big Creek is more mineralized, usually less colored,
and the pH is higher than that of Little Creek. The higher mineral
content of water in Big Creek is due mostly to higher concentrations
of calcium and bicarbonate.


 HILLSBOROUGH RIVER BASIN

 RELATION TO GREEN SWAMP AREA

 The Withlacoochee-Hillsborough overflow channel (C-9, fig. 5),
 previously described with the Withlacoochee River basin, is one of
 the major drainage outlets from Green Swamp during high flows
 and is generally considered to be the head of the Hillsborough River.
 The overflow channel as it leaves the Withlacoochee River is about
 a mile wide. The road fill and bridge of U. S. Highway 98 crosses
 the channel about 1 mile downstream from the Withlacoochee
 River. The entire flow is confined by the road fill to the bridge
 opening which is 200 feet wide.
 White (1958, p.19-24) presents evidence to support an
 assumption that the Withlacoochee-Hillsborough overflow channel
 was formerly the main channel of the Hillsborough River and that
 the Withlacoochee River was once the headwaters of the
 Hillsborough River. Field studies made in the area in 1962 by
 Altschuler and Meyer indicate that the Withlacoochee-Hillsborough
 River overflow was formed prior to natural divergence of the