Basic field data were supplemented for this study by pertinent scientific and technical 

 literature dealing with tlie region and by the National Ocean Survey hydrographic smooth 

 sheets. 



4. Hydrography. 



Tides in the study area vary from 3.5 to 5.8 feet, mean range, and from 4.1 to 6.8 feet, 

 spring range. Tidal ranges decrease progressively from north to soutli (National Oceanic and 

 Atmospheric Administration, 1973a). Tidal currents have not been reported for shelf waters 

 in this region (National Oceanic and Atmospheric Administration, 1973b). Drift bottle 

 studies of circulation over the shelf are sketchy but indicate that over the inner shelf off the 

 northern and central parts of the study area a northward drift predominates in spring and 

 autumn and a southward drift predominates in winter and summer. Off the southern part, 

 the inshore drift is toward the north in summer and south in autumn and spring; winter drift 

 is unknown. The speed of the surface drift is generally under 4 miles per day but a high 

 speed of 10 to 15 miles per day was reported for January off the northern part of the study 

 area (Bumpas and Lauzier, 1965). 



Salinity of the inner shelf waters in the northern and central part of the study area tends 

 to be lower tlian in deeper waters to seaward. They range from about 33.5 to 36 parts per 

 thousand over the inner shelf while salinities farther seaward are generally 36 parts per 

 thousand or higher. Off the southern part where the narrow shelf facilitates mixing of 

 oceanic and coastal waters, inshore salinites are generally higher tlian in the north 

 (Anderson, Moore, and Gordy, 1961). 



The wave climate of the study region is relatively mild. Wave gages at Daytona Beach and 

 off Savannah, Georgia, show that waves more than 5 feet high occur less ihan 10 percent of 

 the time. About 75 percent of the waves recorded off Savannah had a 4- to 9-second period 

 and about 75 percent of tlie waves at Daytona Beach had periods between 6 and 1 1 seconds 

 (from CERC wave data). 



5. Stratigraphy and Geologic History. 



a. General. Knowledge of the geology of the Florida Atlantic coastal region is scant. 

 Most available data concerning the coastal zone are derived from drilled wells, few of which 

 have been subject to detailed stratigraphic study. Cooke (1945) and, more recently, Puri and 

 Vernon (1964) liave summarized the known geology of Florida. Coastal Plain geology of the 

 adjacent Georgia region is summarized in Herrick and Vorhis (1963). Specific regional 

 studies of Florida east coast geology are available in several Florida Geological Survey 

 Bulletins describing geolog)' and water resources of individual counties. Those pertinent to 

 this study are: Tarver (1958), Bermes (1958), Wyrick (1960), Leve (1961a, b), and Brown, 

 et al., (1962). 



Tliere are two prominent subsurface structural features in the region covered by this 

 study. One is the Southeast Georgia Embayment (also called "Atlantic Embayment of 

 Georgia") wliich is centered just north of the Florida border and probably influences 



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