Groundwater exploration using drainage pattern and geophysical data: a case study from Wadi Qena, Egypt (original) (raw)
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The Egyptian Journal of Remote Sensing and Space Science, 2020
In this study Aeromagnetic, ground-based magnetic and satellite imagery data have been processed and analyzed to delineate surface and subsurface structures to clarify its impacts on groundwater flow direction, and to detect the thickness of groundwater aquifer's (accumulation) in the study area. To achieve this target, an interpretation of satellite digital elevation data is processed to generate the main drainage pattern in the area to delineate the Watersheds basins and where the surface water can be accumulated. Moreover, Aeromagnetic data have been used to detect the sedimentary cover in the area, and to assess the thickness distribution of the Nubian aquifer to detect the most eligible aquifer with the largest thickness, consequently the largest amount of groundwater reserve. Also, the ground magnetic survey was conducted in Wadi El Amal to reassure the results obtained from the airborne data. Two main approach techniques were applied to the data. Firstly, the trend analysis applied to the first vertical derivative map to detect main trend analysis and faults. The second approach is to calculate the depth to the basement, which represents the base of the Nubian aquifer in the area under consideration. The final results of the main trend found as follow, the ENE-WSW, NW-SE, and NE-SW trend which found to be is the main trend. The water table in this area is about 100 m, the calculated depth to the basement in the deepest parts study area is ranging between À300 and À700 below ground surface. The integration between satellite techniques and geophysical tools can give us the whole picture of groundwater distribution and its recharge sources.
NRIAG Journal of Astronomy and Geophysics, 2015
Geophysical tools such as magnetic, gravity and electric resistivity have been used to delineate subsurface structures, groundwater aquifer around Cairo-Belbies Desert road. A dipole-dipole section was measured at the central part of the study area with 2100 m length and electrode spacing 50 m for greater penetration depth. The results of the inverse resistivity data indicate that the study area includes two groundwater aquifers at different depths. The shallow aquifer water is near the surface and the deep aquifer lies at depth of about 115 m and exhibits low resistivity values ranging from 20 to 100 ohm m. One hundred and fifty-two gravity stations were measured using Autograv gravimeter (CG3), different gravity corrections (drift, elevation and latitude corrections) were applied. The corrected data represented by Bouguer anomaly map were filtered into regional and residual gravity anomaly maps. The residual gravity map indicates that the area is dissected by many faults with NW-SE, N-S, E-W and NE-SW trends. One hundred and fifty-three ground magnetic measurements are collected using two Proton magnetometers (Envimag). The corrected magnetic data are represented by total magnetic intensity map that was reduced to the magnetic pole. 3D magnetic modeling was applied to detect the depth
Geophysical Journal International, 2012
This study aims to investigate the shallow and deeper section to delineate the groundwater aquifer and structural elements which dissect the study area. Added, the study aims to define the depth to a basaltic body and evaluate the quality of groundwater through interpretation of the geophysical, geological and boreholes data. Geophysical data have been measured, processed and interpreted in two-and three dimensions using special codes prepared by authors and commercial software. The results of interpretation indicate that the study area composed of two aquifers, the first is the Miocene aquifer and the second is Oligocene aquifer. The depth of the Miocene aquifer is ranging from 32.5 to 80 m. Its water quality is good and suitable for drinking and agricultural purposes; where the salinity ranges from 550 to 2200 g l-1 and the total hardness is ranging between 16.7 and 108.5 g l-1. The depth of the upper surface of basaltic body is ranging from 70 to 375 m and the depth of lower surface of basaltic sheet is ranging from 133 to 410 m. The area is dissected by fault elements of NW-SE, NE-SW and N-S trend.
Arabian Journal of Geosciences, 2009
Different geophysical tools such as geoelectric, gravity, and magnetic have been applied to detect groundwater potentiality and structural elements, which controlled a geometry of the groundwater aquifers in the study area. Nineteen vertical electrical soundings measured using ABEM SAS 4000 equipment through Schlumberger configuration of AB/2 ranged from 1.5 to 1,000 m; the quantitative interpretation was carried out using manual and analytical techniques. The results of quantitative interpretation used to construct six geoelectrical crosssections indicate that the subsurface sequence of the study area consists of seven geoelectrical units. These units are Quaternary sand sheet and sand dunes, Quaternary aquifer, marly limestone, clay, sandy clay, clay with sandstone intercalation, and deep Nubian sandstone aquifer. The isopach map of the Quaternary aquifer exhibits thickness of the Quaternary aquifer that increased at the northern and southern part (50 m) and decreased at the eastern and western part (5 m), and the depth of the aquifer increased at the northern part (40 m) and decreased at the central part to 6 m. The isoresistivity map of the aquifer shows a high resistivity at the northern part but the southern part reveals low resistivity according to the lithology. The water salinity increases in the direction of groundwater flow from 500 to 10,500 mg/l. The low water salinity is due to direct recharge from El-Sheikh Zayed Canal, which supplied fresh water to this area. Sixty-five gravity stations were measured using Auto-Grav gravity meter; different gravity corrections were applied on raw data. The corrected gravity values were plotted to represent a Bouguer anomaly map; the residual gravity anomaly map was used for delineation of the fault elements. The area was dissected by different fault elements of trends NW-SE, NE-SW, and E-W. In addition, 65 ground magnetic stations were measured at the same sites of gravity stations. The results of magnetic interpretation indicate that the depth of the basement is shallow at the western and southern parts of the area (4,500 m), but the central part exhibits greater depth of 7,900 m.
2021
This study aimed to delineate groundwater and the structural trends in the East of Cairo City. For this aim, we carried out different geophysical approaches such as gravity, magnetic, and electric methods. For the gravity and magnetic data analysis, we used filtering, Euler deconvolution, and radially power spectrum techniques. In addition, 3-D modeling was performed on the magnetic data only. The radial power spectrum technique shows that the depths of the surface anomalies corresponding to the short wavelength are 0.48 and 0.5 km. While, the depths of the surface anomalies corresponding to the long wavelength are ranging from 2.74 to 2.33 km from gravity and magnetic interpretation, respectively. The Euler deconvolution revealed that the investigation area was under the effect of several fault trends; a major NW-SE trend and NE-SW and NW-SE as minor trends for gravity data. While the fault trends are in N-S and NE-SW directions for RTP magnetic data. The 3-D modeling results show ...
The area south Abu Bayan El Qibli, lying on the road of Darb El-Arbeen witnesses, a development stage aiming to the reconstruction of small communities in that part, through the expansion of the cultivated areas and hence promoting the employment rate. The increasing activities in that part of Egypt have caused an ever growing demand for water. The present study shows integrated geophysical exploration techniques to detect the aquifer conditions. These techniques include land magnetic survey and 2D electric imaging profiles. The target of the present study is to detect the predominate subsurface structures of the southern part of the Western Desert of Egypt to determine the total thickness of the sedimentary cover, and consequently, the basement features, which probably control the upper cover thickness. The high topographic land includes Gebel Abu Bayan El Qibli at the northern part of the study area. The moderate topographic land includes cresenic sand dunes and the low topographic land includes the depression, which comprises El Tamaneen village around the asphaltic Darb El-Arbeen road. The Nubian Sandstone sequence is built up of Upper Cretaceous rock units (Dakhla shale Formation, Kiseiba Formation and Taref Formation) and Paleozoic-Mesozoic Sandstone sequence and is overlying directly the Pre-Cambrian basement rocks. The Paleozoic-Mesozoic section, Taref and Kiseiba Formations are the main aquifer. The interpretation results of magnetic data revealed that, the minimum estimated depth to the basement surface is about 183 m at the southwestern side of the area and increases toward the northeastern side to up to 858 m. In the modeled magnetic profile P3, an expected normal fault at a distance of 6 Km from the beginning of the profile was found, whereas its throw due the southern direction. Two large basins were detected in the middle part of the study area. It is observed that, the resistivity values of the 2D imaging profiles were classified into three ranges of resistivities (less than 1to 8 Ohm-m) representing the conducting shale, fine sand and clay, (33 to 134 Ohm.m) representing dry loose sand and gravel, and (542 to more than 8800 Ohm.m) corresponding to the massive basement and the overlying sandstone. The promising water layer was found at resistivity values ranging from 43 to 165 Ohm.m in the two long 2D profiles (PI & PIV). Also, a fault was detected at a distance of 520m from the start of the profile (PII), where its throw due the southern direction. It causes a change in the lithologic deposits that exhibited high resistivity. According to the conclusion results, the depth to water is expected at more than 200m. as indicated from the two 2D imaging profiles (PI & PIV). The management of the groundwater in this vital aquifer is recommended to face the future hydrological problem arisen from the drawdown of water table and increasing the salinity.
Delineation of the subsurface geologic setting is a prerequisite for understanding the possibilities and limitations of groundwater recharge. Tushka area represents one of the most promising areas to become the source of food for Egypt in the near future. This area is characterized by available groundwater and soil resources. Nubian Sandstone aquifer, that overlies directly the basement rocks, represents the main water-bearing section in this area. The geomagnetic survey in the present study is involved by carrying out 24 land magnetic profiles with the object of determining the depths of the basement rocks, detecting the subsurface geologic structures, and establishing the basement relief: in addition to their impact on the groundwater accumulations. The interpretation results of the modeled land magnetic profiles have been used for the construction of the depth to basement surface and the basement relief contour map. These maps revealed that, the depths to basement range from zero meter in the northern and western parts to about seven hundred meters at the middle and southern parts. This variation is due to the effect of structural faults, which leads to construct a group of horsts and grabens. These faults have two directions: NE-SW and NW-SE.
Jordan Journal of Civil Engineering, 2009
Geological contacts in a complex subsurface terrain have favorable potentiality for groundwater; particularly in semiarid/or arid areas. Magnetic and DC resistivity surveys were proposed and conducted at Wadi Fatima for the groundwater exploration in this geologically complex media. Magnetic survey was used to delineate the basement structures which control the groundwater flow. On the other hand, DC resistivity profiling and sounding techniques were used to investigate and ensure the potentiality of the groundwater occurrence in the structurally complex basement. Magnetic data were subjected to analytic signal analysis, where it showed clearly the complexity of the study area. Many magnetic contacts were delineated at the maximum amplitudes of the analytic signal curves. Two selected profiles along the Wadi have been quantitatively interpreted using analytic signal, spectral analysis, horizontal and vertical derivatives. These analyses delineate the geological structures that may a...
Earth Sciences, 2005
Magnetic and DC resistivity methods are utilized at Wadi Malakan, Makkah Al-Mukarramah region, Saudi Arabia. Land magnetic survey is conducted to identify the main structure and the depth to the basement along the surveyed part of the wadi. 2-D Euler deconvolution technique is used and reveals the depth to magnetic sources and possible faults that may affect the groundwater flow. Profiling using Wenner array is used to identify the minimum resistivity value along each profile to provide the optimum location for conducting sounding. Sounding using Schlumberger array is used to delineate the saturation zones and the depth to basement at most significant selected sites. The integration between magnetic and DC resistivity methods provides valuable information about the possible location of saturated zones at the conducted part of the wadi. The results of the interpreted vertical electrical resisitivity soundings at VES6004 and VES6010 are confirmed by drilling. The coefficient of anisotropy is calculated and found to be very low which reveals that there is no preferential direction for current flow in which the average transverse resistivity is almost the same as the average longitudinal resistivity which implies that the wadi deposits are not stratified.
Arabian Journal of Geosciences, 2015
In the present study, three geophysical techniques (land gravity, electrical resistivity, and land magnetic) have been applied to identify and evaluate the groundwater occurrences in the studied area, which lies between latitudes 29°18′ and 29°52′ N and longitudes 33°25′ 34°32′ E. Twenty-six deep vertical electrical sounding (VES) stations were measured and interpreted to delineate the Nubian sandstone aquifer in the area. The depth of upper surface of the aquifer varies from 483 to 1079 m, and the resistivity values of the aquifer range from 109 to 522 Ohm-m which represents the fresh water aquifer in the study area. The results of gravity interpretation indicate that the area is dissected by different fault elements of different directions such as NE-SW trend parallel to the Gulf of Aqaba, NW-SE trend parallel to the Gulf of Suez, and E-W trend parallel to the Mediterranean Sea. The depth of basement rocks range from 2100 to 4300 m.