1D and 3D inversion of VES data to outline a fresh water zone floating over saline water body at the northwestern coast of Egypt

Seawater intrusion is a widespread environmental problem in the Egyptian coastal aquifers. It affects the groundwater used in domestic and agricultural activities along these coasts. In this study, resistivity survey in the form of Vertical Electrical Sounding (VES) was conducted at ZAWYET EL HAWALA cultivated site, northwest coast of Egypt to outline a freshwater zone overlies the main saltwater body, and to determine the most suitable location for drilling water well for irrigation purposes. The VES data were measured at 11 stations in the studied site. After processing, the data were inverted in 1-D and 3-D schemes and the final model was presented as resistivity slices with depth. The results indicate that the effect of saltwater intrusion was observed, as low resistivity values, at 7.5 m below ground surface (bgs) at the northern part of the study area (toward the Mediterranean Sea), and extends southward with increasing depth covering the whole area at about 30 m bgs. The fresh water zone shows a minimum thickness of less than 7.5 m at the northern side and a maximum thickness of about 20 m at the southern side of the area. The proper site for drilling water well tap and the freshwater zone is the location of VES6 or VES9 with a maximum well depth of about 20 m bgs. The water withdrawal from the proposed well should be controlled not to raise the main saline water table in the well site. The main sources of the freshwater zone are the rainfall and surface runoff descending from the southern tableland. Excess rainfall and surface runoff can be avoided from direct discharge to the sea by collecting them in man-made outlined trenches and re-using the stored water in irrigation during the dry seasons

Indirect preservation of Egyptian historical sites using 3D GPR survey

Non-invasive geophysical techniques are used to collect information about the environmental risks that threaten the historical sites in Egypt and indirectly preserve them. In this study the modern 3D-GPR imaging at two important Egyptian sites was applied for preservation purposes. The first site is the internal Piazza of Al-Azhar Mosque, while the second site is the proposed route through which the Ramesses-II statue will be transported to the main entrance of the Grand Egyptian Museum. The 3D-GPR surveys were performed using the 100 MHz GSSI antenna at Al-Azhar Piazza and the Hi-Mode IDS GPR system with 200 and 600 MHz dual antenna at the Grand Egyptian Museum. The analysis and interpretation of the 3D-GPR data at the first site led to image large voids and walls objects, which are very likely to represent shallow water tanks that were frequently used in the past. One main water tank was recently discovered at the southern part of the piazza, which causes water leakage to the walls of Al-Azhar Mosque. Moreover, the GPR results at the second site have showed that the proposed route is totally covered by sand and has neither cracks nor cavities or any other archeological features. There is only a PVC water pipe, which is buried at a relatively shallow depth of 0.25 m. Such PVC pipe might collapse during the transportation of Ramesses-II Statue and should be taken into consideration. Keywords: Al-Azhar Masijid Piazza, Ramsess-II Statue, Grand Egyptian Museum, 3D-GPR survey, Ancient water tanks, Buried PVC pip

The Egyptian pyramid chain was built along the now abandoned Ahramat Nile Branch

The largest pyramid field in Egypt is clustered along a narrow desert strip, yet no convincing explanation as to why these pyramids are concentrated in this specific locality has been given so far. Here we use radar satellite imagery, in conjunction with geophysical data and deep soil coring, to investigate the subsurface structure and sedimentology in the Nile Valley next to these pyramids. We identify segments of a major extinct Nile branch, which we name The Ahramat Branch, running at the foothills of the Western Desert Plateau, where the majority of the pyramids lie. Many of the pyramids, dating to the Old and Middle Kingdoms, have causeways that lead to the branch and terminate with Valley Temples which may have acted as river harbors along it in the past. We suggest that The Ahramat Branch played a role in the monuments’ construction and that it was simultaneously active and used as a transportation waterway for workmen and building materials to the pyramids’ sites