Hydrostratigraphy of central nile delta, egypt, using geoelectric measurement
Abstract
Combined sedimentological, hydrogeological and geoelectrical studies were conducted to delineate the hydrostratigraphy of the Central Nile Delta area and to define the locations of the clay-rich zones in the main water bearing formations. Forty four vertical electrical sounding (VES) using Schlumberger configuration were made and the data were interpreted by a computer iteration technique. The geoelectric sections reveal four subsurface layers, with increasing depth: clay, sandy clay, fine-to-medium sand, and coarse sand with gravel. The first two layers (Bilqas Formation) recorded average resistivity values ranging between 1 and 15 ohm-m, while the deepest layers, constituting the main aquifer (Mit Ghamr Formation) attained values from 22 to 100 ohm-m. At some test sites, the sandy clay layer was missing. Lenses and pockets of clays were also found locally in the main water bearing formation. Considerable lateral variations in the layer's resistivities were attributed mainly to increase of groundwater salinity from the south towards the north. Chemical data have indicated that the area can be subdivided into northern highly brackish water area (TDS values from 4000 to 10000 mg/l), central slightly brackish water area (TDS values from 1000 to 4000 mg/l) and southern fresh water area (TDS values less than 1000 mg/l). Sedimentological data, based on examining sediment samples from twenty three wells, were used to conduct a panel diagram for the Central Nile Delta area.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....1415A