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CAROLINA GEOLOGICAL SOCIETY
Guidebook for 1992 Annual Meeting
Pages 71-76
HYDROSTRATIGRAPHY OF THE SAVANNAH RIVER SITE REGION, SOUTH CAROLINA AND GEORGIA
Rolf K. Aadland 1 , Paul A. Thaye 2 , and Andrew D. Smits 3
1 Environmental Sciences Section, SRTC, Westinghouse Savannah River Co., P.O. Box 616, Aiken South Carolina 29802
2 Department of Earth Sciences, UNCW, 601 South College Road, Wilmington, NC 28403-3297
3 Science Applications International Corporation, 360 Bay Street, Suite 200, Augusta, GA 30901
INTRODUCTION
Numerous studies have described and modeled the
hydrostratigraphy in and around the Savannah River Site
(SRS) area (Siple, 1967; Colquhoun and others, 1983;
Brooks and others, 1985; Clarke and others, 1985; Miller,
1986; Aucott and others 1987; Aucott, 1988; Krause and
Randolph, 1989). Central to all previous studies is the one to
one correspondence between hydrostratigraphic units and
lithostratigraphic units. This method is difficult to apply
regionally owing to the abrupt facies changes in stratigraphic
units of the updip Coastal Plain sequence. For example,
lithostratigraphic units included in aquifer and confining
units at one location are often not present or are of different
hydraulic character elsewhere.
Detailed analysis of drill core, geophysical, and hydrologic
data from 144 wells provides the basis for a hydrostratigraphic
classification system of the SRS region (Figs. 1
and 2) (Aadland and others, 1992a,b), which makes use of
hydrologic properties, most significantly hydraulic conductivity,
porosity, and specific storage. These criteria eliminate
any “formal” reliance of the classification scheme on lithology,
age, geologic history, stratigraphic position or other feature.
The resultant classification scheme ranks
hydrostratigraphic units at four levels, which from highest to
lowest are (Aadland and others, 1992a,b): 1). Hydrogeologic
province, 2). Hydrogeologic system, 3). Hydrogeologic unit,
and 4). Hydrogeologic zone (informal).
A hydrogeologic province is a major body of rock and/
or sediment that behaves as a single hydrologic unit on a
regional scale. Aquifer and confining systems may be composed
of two or more aquifer and confining units that transmit
(or impede) ground water on a regional basis. Where
aquifer systems coalesce, the unified aquifer system is
named by hyphenating the names of the uppermost and lowermost
constituent systems.
An aquifer unit is mappable (>400mi 2 ) body of rock or
sediment that is sufficiently permeable to conduct ground
water and yield significant quantities of water to wells and
springs (Burt, 1987a, b). A confining unit is a mappable
body of rock or sediment of significantly lower hydraulic
Figure 1. Generalized hydrostratigraphic cross-section of the SRS region.
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