12
River flows p
underground Worthington
High Springs
10 0 20 Miles
FIGURE 4.-Flow of the Santa Fe River passes underground in a 3-mile
reach between Worthington and High Springs.
Several of the rivers in northern Florida, including the Santa Fe and the Suwannee, have cut channels into the limestone formations that compose the principal ground-water reservoir. During low flows, these rivers are fed by the ground water. During high flows, water from the rivers pours into the limestone.
its name, "surface water" or "ground water," changes according to mode of occurrence at the moment.
Lakes and ponds, scattered over the area, number in the thousands. Large swamps border most of the west coast and occupy much of the St. Johns River basin. The principal streams of the area include the Suwannee, St. Marys, St. Johns, Oklawaha, Santa Fe, Hillsborough, and Waccasassa Rivers, two rivers named Withlacoochee, and Olustee and Black Creeks (see fig. 6). The St. Johns River is one of the few rivers of the world that flow northward throughout their courses.
The figure shows the average flows of these streams so far as is indicated by the few data available. A notable deficiency is the lack of records on the flow of the lower St. Johns River-the flow is unknown over a reach of 150 miles. The flow of the Suwannee River near Bell, Fla., averaging 8,000 cubic feet a second, is by far the largest of any on which adequate data are available, but