By Michael F. Peck (1), John S. Clarke (1), Camille Ransom, III, (2), and Christopher J. Richards (3)
AUTHORS: (1) U.S. Geological Survey; (2) South Carolina Department of Health and Environmental Control; (3) Northwest Florida Water Management District
REFERENCE: Georgia Geologic Survey Hydrologic Atlas 22, 1 sheet

Introduction

The Upper Floridan aquifer is part of the Floridan aquifer system that underlies most of the Coastal Plain of Georgia, southern South Carolina, extreme southeastern Alabama, and all of Florida (Miller, 1986). The aquifer system is one of the most productive in the United States and a major source of water in the region. Approximately 700 million gallons per day (Mgal/d) of water was withdrawn from the Floridan aquifer system during 1995 in Georgia. Most of this water was withdrawn from the Upper Floridan aquifer mainly for industrial and irrigation purposes (Fanning, 1997). To monitor seasonal and long-term water-level fluctuations and trends in the Upper Floridan and other aquifers in Georgia, the U.S. Geological Survey (USGS), in cooperation with the Georgia Department of Natural Resources Environmental Protection Division, Georgia Geologic Survey, and other State and local agencies, maintains a network of approximately 1,050 water-level monitoring wells, including 153 wells equipped with continuous water-level recorders.

This report illustrates and describes the potentiometric surface of the Upper Floridan aquifer in Georgia and adjacent parts of Alabama, Florida, and South Carolina for May 1998, and water-level trends in Georgia for the period May 1990 to May 1998. The potentiometric surface, which represents the altitude at which water would have stood in tightly cased wells open to the Upper Floridan aquifer, was constructed by using water-level and pressure measurements collected from more than 2,000 wells during May 1–26, 1998. The potentiometric-surface map is used to better understand ground-water flow in the Upper Floridan aquifer. In addition, the potentiometric-surface map and related water-level data will be used in the development of ground-water-flow models of the aquifer system for the coastal area of Georgia.