Integrating Lithofacies Data into Hydrogeological Studies: Examples from the Savannah River Site, S.C.
Integrating detailed sedimentological data (e.g., grain size, sorting and degree of cementation) and lithofacies distribution into numerical ground-water models improves prediction of ground-water flow and contaminant migration paths beneath the central Savannah River Site (SRS). The hydrostratigraphy of the SRS comprises fluvial, deltaic, and shallow marine sand, mud and calcareous sediments that exhibit abrupt facies changes over short distances. This study utilizes well test data, down-hole geophysical logs and detailed foot-by-foot descriptions of continuous drill core from over 100 wells to develop stratigraphic and lithofacies maps of aquifers and confining units beneath the 15mi2 General Separations Area at the SRS. The resultant isopach, structure conto r, isolith, clastic ratio, and sand and clay distribution maps illustrate variations in geometry and texture within each hydrostratigraphic unit.
Data from the stratigraphic and lithofacies maps have been integrated into a ground-water flow model for the General Separations Area. The model yields complex three-dimensional flow patterns that contribute significantly to understanding ground-water flow and contaminant migration paths beneath the central SRS. Model results demonstrate the effectiveness of incorporating detailed lithofacies data into flow and transport models.
AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995