Home Abstract >Introduction - Regional Analysis - Summary of Previous Work Hydrogeology Hydraulic Properties of the Aquifer System Regional Flow System Groundwater Development Groundwater Chemistry Potential for Future Development References PDF Version

By Richard H. Johnson and Peter W. Bush
Professional Paper 1403-A

Hundreds of reports describing the hydrology, geology, and water chemistry of the Floridan have been published. Many of these were used in making the observations described in the Professional Paper 1403 series, and they are referred to throughout the series. A few provided major contributions to the knowledge of the Floridan aquifer system and are noted here.

Matson and Sanford (1913) in Florida and Stephenson and Veatch (1915) in Georgia provided the first comprehensive descriptions of the hydrogeology, ground-water resources, and development of the aquifer system on a county-by-county basis. Their interpretations, which were based on limited data, are truly impressive and provide the best descriptions of the aquifer system prior to extensive development.

The earliest known potentiometric-surface map of the Floridan was prepared by Gunter and Ponton (1931), based on water-level measurements made in 1928, and covers most of northern peninsular Florida. The pioneer work of Stringfield in the early 1930's identified a regional flow system in Florida that included several Tertiary limestone units. Stringfield (1936) presented a potentiometric surface map which showed for the first time the essential features of this flow system in peninsular Florida. The contours on this map suggest areas of natural recharge and discharge and indicate general directions of ground-water movement from recharge to discharge areas. A major area of high head and thus potential recharge was shown to exist in central Florida. Later Parker and others (1955) concluded that this flow system represented a single hydrologic unit (composed of several Tertiary carbonate formations) and named the unit the "Floridan aquifer."

Important contributions to the paleontology and stratigraphy of the Tertiary limestone units include those by Applin and Applin (1944, 1964), Herrick (1961), and Pun and Vernon (1964). Herrick and Vorhis (1963) first recognized and named the "Gulf Trough," an important subsurface structural feature that exerts major control on regional ground-water flow and water chemistry in southeast Georgia.

Saltwater has encroached locally near some coastal pumping centers. Notable studies of this problem include an early State-wide summary in Florida by Black and others (1953) and an analysis of rising saline water at Brunswick, Ga. (Wait and Gregg, 1973).

The relation of the regional flow system to water chemistry has been investigated by Back and Hanshaw (1970), who described changes in water chemistry from recharge to discharge areas. They also proposed a hypothesis for dolomitization based on mixing of freshwater and saline water along a moving freshwater-saltwater interface (Hanshaw and others, 1971).

Studies of the ground-water hydraulics have proceeded from simplified analytical approaches in the 1940's to computer simulation in recent years. A notable early study was made by Warren (1944), who related widespread changes in artesian head to variation in the pumping rates at Savannah, Ga. Warren calculated head declines that would occur with increased pumping. More recently Counts and Krause (1976) used a computer model to analyze the effects of pumping at Savannah. Wilson (1982) used computer simulation to project water-level declines resulting from proposed phosphate mining in west-central Florida. Solute transport modeling was used by Bredehoeft and others (1976) to simulate the movement of saline water in the Floridan at Brunswick, Ga.

The definitive reference for the hydrogeology of the Floridan aquifer system is by Stringfield (1966). This 226-page volume presents area! hydrogeologic descriptions by county, with emphasis on the water-bearing properties of the various geologic units forming the Floridan aquifer system. Considerable hydraulic and geochemical data and regional interpretation are also presented.

Finally, it should be noted that the greatest source of information on the aquifer system is contained in the hundreds of reports published primarily by the States of Florida, Georgia, and South Carolina and in the USGS's Open-File Report and Water-Resources Investigations series. Many of these studies were made by the USGS in cooperation with various State, county, and municipal governments and Florida's water-management districts. These reports provide the basic hydrologic data as well as interpretations of the local hydrology without which this regional study could not have been successfully made.