Potentiometric Surface of the Upper Floridan Aquifer in the Ichetucknee Springshed and Vicinity, Northern Florida, September 2003

The Upper Floridan aquifer is a highly permeable unit of carbonate rock
extending beneath most of Florida and parts of southern Alabama, Georgia, and
South Carolina. The high permeability is due in a large part to the widening of
fractures that developed over time and the formation of conduits within the
aquifer through dissolution of the limestone. This process has also produced
numerous karst features such as springs, sinking streams, and sinkholes in
northern Florida. These dissolution features, whether expressed at the surface
or not, greatly influence the direction of ground-water flow in the Ichetucknee
springshed adjacent to the Ichetucknee River. Ground water generally flows
southwestward in the springshed and discharges to the Ichetucknee or Santa Fe
Rivers, or to the springs along those rivers. This map depicts the September
9-10, 2003, potentiometric surface of the Upper Floridan aquifer based on 94
water-level measurements made by the Suwannee River Water Management District.
Ground-water levels in this watershed fluctuate in response to precipitation
and due to the high degree of interconnection between the surface-water system
and the aquifer.

[Summary provided by the USGS.]