THE USE OF SHALLOW SEISMIC AMD HYDROGEOLOGIC OBSERVATIONS TO CHARACTERIZE THE ANCIENT HIERAKONPOLIS TEMPLE-TOWN SITE IN SOUTHERN EGYPT

The ancient Temple-Town of Hierakonpolis near Edfu in southern Egypt has been characterized using shallow seismic and hydrogeologic field measurements. This site was continuously inhabited from at least 3800 B.C. through Roman times and is important to the study of early towns and kingships recorded in artifacts recovered over a century ago. The Temple-Town complex, covered by aeolian sands, has a shallow water table and grades to the irrigation practices in the surrounding floodplain. Any future excavations will require continuous dewatering to depths up to 5 m or more to reach the base of the buried structures. High-quality data from over 150 seismic profiles have been used to: (a) map the depth of the water table (1-3 m) beneath the site and in adjacent areas, (b) locate localized anomalies believed to be associated with buried man-made structures or objects; (c) discover a major reflecting boundary, interpreted to be an ancient channel of the Nile ~100 m beneath the site; (d) discover a deeper reflector at ~150 m; and (e) another ubiquitous shallow reflector at ~30 m, the origin and significance of which is not yet known. The variable water-table depth distribution over the site has been determined from bimonthly observations in 2-5 m deep auger holes at 146 locations and from shallow seismic refraction profiles. Water table elevation, water temperature (March, low of 20-23°C; Sept, high of 30-32°C), salinity (up to 65 ppt) and specific conductance, help to characterize the groundwater flow regime induced by nearby irrigation activities. The water table with a relief of 1.5 m, fluctuates 11 to 58 cm with a high in December and a low in February. Specific conductances, up to 100,000 µs, fluctuate with a late summer seasonal high. Soil temperatures at 1 m depth in 115 auger holes range from a March low of 18-25°C over the site to a September high of 31-38°C. All reflect shallow hydraulic conductivity variations and groundwater flow patterns. Deeper hydraulic conductivity variations must still be determined from additional drilling and hydrologic tests to fully characterize the flow regime and select a dewatering strategy for the site. This large body of subsurface observations, together with surface topographic and geologic observations, have been incorporated into a GIS database to facilitate analysis and interpretation.