الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Establishing new communities is one of the strategic plans of the Egyptian governments during the last decades. One of the targeted localities for such plan is the West Nile Delta area. The area under investigation is located to the west of Nile Delta on both sides of the Cairo-Alexandria desert road, between latitudes 30° 00′ and 31° 00′ N, and longitudes 29° 40′ and 30° 40′ E, as it covers an area of about 10656 Km2. To help such national plan, the present study aims to delineate the subsurface structures and hydrogeological regime of the study area. This will be conducted through qualitative and quantitative interpretation of the available geophysical data (gravity, magnetic, geoelectric resistivity, and electromagnetic data).
The gravity and aeromagnetic data were subjected to different processing techniques using Oasis Montaj ver.7 (2008) software package. These techniques include: RTP of the total intensity magnetic data, spectral analysis, (lowpass, highpass and bandpass) filtering, upward continuation, first and second vertical derivatives, horizontal derivative, analytical signal (total gradient), tilt derivative, theta map, 3D Euler deconvolution and finally 2D forward modeling technique. As a result, the average depth levels of 12.5, 5.8 and 2.1 km reflecting deep-seated, intermediate and shallow sources respectively. The sedimentary cover varies from 2 to 6.5 km where the thickness of the sediments increases northward and eastward. Also the depth to Conrad discontinuity ranges between 17 and 22 km, whereas the thickness of the crust varies from 31.5 to 32 km. A deduced structural-tectonic map is constructed based on the geological information and gravity and magnetic interpretation. This map shows that the dominating trends are NE, NW, and E-W. Many horsts and grabens are existed all over the study area and may play a role in the presence and movements of the groundwater.
The geoelectric resistivity survey includes 93 Vertical Electric Soundings (VES). The field measurements were carried out using Schlumberger array with AB/2 ranging from 1.5 m to 700 m, whereas the electromagnetic survey includes 26 TEM soundings near selected VESes with loop spreading 50x50m using “SIROTEM MK3” system. Seven iso-apparent resistivity contour maps have been prepared in order to illustrate the prevailing subsurface conditions in a clear readable manner. The quantitative interpretation was conducted through one-dimensional resistivity inversion for both VES and TEM data using the software IX1D from Interpex Ltd. As a result, 10 cross-sections (from VES) and 3 cross-sections (from TEM) were constructed and well correlated with the available borehole. The depth to the main aquifer ranges from 6 m at the northern part near the Nubariya city to about 90 m at the southern parts where it increases to the south and south east directions. The inferred faults from the geoelectric sections are traced and collected to construct a structure map. A major fault (Fi) passes parallel to the northeastern edge of Wadi El Natrun with a southwest thrown. Another two important faults (Fii and Fiii) passes nearly perpendicular to Wadi El Natrun axis with thrown nearly to the east, in addition to five faults parallel or perpendicular to Alex-Cairo road. It is worth to mention that Wadi El Natrun and its lakes are structurally controlled by faulting systems trending NW direction