IMPACT OF THE GEOLOGIC SETTING ON THE GROUNDWATER OCCURRENCE IN BERKASH AREA –WEST NILE DELTA USING THE GEOELECTRICAL TECHNIQUE | ||
| Journal of Egyptian Geophysical Society | ||
| Volume 10, Issue 1, 2012, Pages 73-84 PDF (1.4 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jegs.2012.384982 | ||
| Author | ||
| M.S.M. Barseem | ||
| Researcher in Desert Research Center | ||
| Abstract | ||
| Several problems related to groundwater, such as less potentiality and inadequate quality were encountered during the reclamation of the studied area. The present area lies close to km 35, north of the Cairo - Alexandria desert highway with an area of about 16 km2. The delineation of the subsurface setting helps much in such circumstances. For this purpose, 16 Vertical Electrical Soundings (VES) were carried out. In addition, available data of 20 wells drilled in the area were utilized. The interpretation of the VES curves illustrated that the rock succession under the area consists of six layers; a surface layer formed of alluvial deposits with a thickness of up to 12 m and electrical resistivity of 18 - 366 Ohm.m., followed downward with a thick dry zone with a thickness of 113 - 154m and resistivity of 28 - 91 Ohm.m. This second layer is formed of sand , clayey sand and sandy clay. The third layer downward is similar in composition to the second layer but is saturated with water of the Miocene aquifer. It varies in thickness from 25 to 133 m and in resistivity from 24 to 50 Ohm.m. The calculated clay percentage in this area was found to vary from 5.1% to 71.6%, which partly explains the variation in water salinity of this layer from 326 to 1587 ppm. The third layer is underlain by a clayey layer ranging in thickness from 9 to 24 m and in resistivity from 6 to 18 Ohm.m. The fifth member of the succession is formed of basalt with a thickness of 32 - 47 m and resistivity range of 106 - 928 Ohm.m. The last layer downward is formed of sandy clay and clay belonging to the Oligocene aquifer with a resistivity range of 5 - 69 Ohm.m. The interpretation of the geoelectrical data together with the available well data indicted the presence of six normal faults forming a basin in the middle part of the study area. Based on the depth to water, thickness, clay percentage (water quality) of the shallower aquifer, a priority map was constructed. The map indicated clearly that the promising parts of the area, as to the drilling of water wells, are the eastern and northern parts. In the southern and western parts, the deeper aquifer (Oligocene) lying under the basalt sheet may be utilized for relatively better water quality. VES stations 26, 35 and 36 are considered to be the best sites for the drilling of water wells reaching to the Oligocene aquifer in these part of the area. | ||
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