Ground-water withdrawals from the Floridan aquifer system in northeastern Florida accounted for about 90 percent of the total freshwater use in 1999. Water-use data have been collected by the U.S. Geological Survey and the St. Johns River Water Management District since 1965. In 1965, total ground-water withdrawals in Duval and surrounding counties (St. Johns, Clay, and Nassau)
was about 191 million gallons per day (Mgal/d), of which 127 Mgal/d was from Duval County (Marella, 1995). In 1999, withdrawals increased to about 272 Mgal/d, of which 152 Mgal/d was from Duval County. Of the total water used in Duval County in 1999, 74 percent was for public supply, 11 percent for commercial-industrial self-supplied, 9 percent for domestic self-supplied, 3 percent for thermoelectric power generation, 2 percent for recreational, and 1 percent for agricultural irrigation (R.L. Marella, U.S. Geological Survey, written commun., 2002).
Figure 2. Total ground-water use in Duval County and adjacent counties, Florida, 1965-1999 (from Marella, 1995, 1999; and R.L. Marella, U.S. Geological Survey, written commun., 2000). [