الفهرس 
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Abstract
The successful exploration of groundwater in sedimentary terrain, especially in arid and semi-arid areas needs for a proper understanding of its hydrogeological characteristic through the application of geophysical techniques which also increase the possibility of successful drilling of water wells. The application of geophysical surveying represents the best choice in areas of limited information regarding existing wells or hydrogeological data. An adequate and sustainable adaptation strategy is required to ensure the sustainable and sufficient supply of fresh water. Temporal storage of water can help overcome this mismatch in water supply and demand in time, allowing seasonally variable sources of water to be used as reliable water supply (Rambags et al., 2013) The traditional concept of Aquifer Storage and Recovery (ASR) was first introduced as a type of groundwater recharge by Pyne (1995), in which ASR is defined as the storage of water in a suitable aquifer through a well during times when water is available, and recovery of the water from the same well during times when it is needed. According to Sheng, 2005, an ASR system is defined as water managed tool that helps sustain economically recoverable water supply by redistributing available water over a period of time and through a hydrologically suitable space. Recent technical advances and operational experiences have demonstrated that ASR is a feasible and cost effective method to recharge natural aquifers (Pyne, 2005, Maliva and Missimer, 2010). ASR strategy was studied in some Arab countries such as Kuwait and the United Arab Emirates (Abu Dhabi emirate). The investigated area represents a part of the northwestern coastal zone of Egypt. It has excellent locality for land reclamation and tourism projects. It extends for about 65 km along the northwestern coast, which is lying between El Negila on the east and Sidi Barrani on the west. It is bounded by longitudes 25o 58’ & 26o 36’ E and Latitudes 31o & 31o 40’ N, covering an area of about 4000 km2. The area of study consists of a network of minor valleys that cut through and join into six main valleys that finally drain into the Mediterranean Sea. These drainage networks (6 main basins) harvest the rainwater of the occasional events as a surface runoff in the main streams and as a recharging source for the shallow groundwater aquifers in the study area. The climatic conditions of the study area are typically arid. It is characterized by a long hot dry summer, mild winter with little rainfall, high evaporation with moderately to high relative humidity (Yousif et al., 2015). The Mediterranean coastal zone of Egypt receives noticeable amounts of rainfall, especially in winter. No rain is recorded during summer, while occasional heavy rain may occur in autumn. During the period from 1 January 1998 to 1 January 2012, Youssef et al., (2015) found that most parts of El Negila area have received a total precipitation of (2291- 2781 mm) and annual average of (163.64- 198.64 mm), in addition to estimation the annual precipitation during 1 year (2012) where its maximum value was 196.8 mm in El Negila area. This study attempts to understand the geoelectrical characteristics of the subsurface geological formations, determine the vertical and horizontal extensions of the lithological succession with its facies characteristics and to define the best locations for drilling water wells. In addition to understand the feasibility of the proposed ASR sites in the aquifer. The present study provides an integrated approach using geophysical data and GIS data to explore the groundwater potentiality and the ability to construct an aquifer storage and recovery system (ASR) in arid to semi- arid areas such as the area of interest. Regionally, there are four main geomorphologic units in the area of investigation: coastal plain, piedmont plain, tableland, and drainage basins The coastal plain occupies a strip of land stretching adjacent to the shore line. It extends in an east– west direction for about 60 km parallel to the Mediterranean coast with average width of ranging from 5 to 10 km. The maximum inland extension of this plain is about 5 km from the sea, north to south direction (Yousif et.al.,2015). This plain is irregular and associated with the presenece of several landforms such as Wave– cut platform, Beach scarp, Coastal cliff, Modern sand beach, Near shore sand dunes,Salt marshes lakes, Elongated lagoons, Elongated ridges and Elongated depressions. Piedmont plain is considered as an extended sloped surface which separating the southern tableland from the northern coastal plain. It has elevation ranges from 30 to 90 m above sea level and width varies from few meters to several kilometers. This plain is distinguished by presence of inland depressions between the ridges. This plain has elongated shape and characterized by undulated surface. Its surface represents the sides that receive the weathering products transported by numerous wadies. (El Shazly, 1964 ;Yousif et. al., 2015). Southern tableland represents the northern part of the great Marmarican Homoclinal plateau and stretchs to the Qattara Depression. It rises for about 50 meters above the coastal plain. It is highly dissected by deep dry sequent wadies. These wadis become of the hanging type and pass into the piedmont trough conspicuous water fall at the edge of the tableland. The surface of the tableland area is generally barren with regard to soil and vegetation. This geomorphic unit represents the principal watershed area. It has a general slope due north and east directions, that allows surface runoff to be directed to the Mediterranean Sea through drainage basins (Yousif et. al., 2015). Drainage pattern; A number of six basins with dense drainage network were extracted in the area of interest by using DEM analyses and ArcGIS program. Theses basins are generally parallel with main channel streaming from the tableland and flow down towards the Mediterranean Sea, consequent to general slope of the land surface. These basins are named from east to west as W. Shammas, W.Alsedrah, W. Al Zowidah, W Qatranah, W. Almaqtalah and W.Altarafayia. These basins are almost characterized by simple dendritic pattern. These basins are covering area ranges between 73.6 km2 at W.Alsedrah (basin No. 2) and 602.6 km2 at W. Almaqtalah (basin No. 6). The stratigraphic sequence of northwestern coastal zone of Egypt is totally composed of sedimentary rocks belonging essentially to Tertiary and Quaternary. The rock exposures of Tertiary are represented by the Pliocene- Miocene rocks. Middle Miocene sediments are found in the form of Marmarica limestone formation which covers a large area of the northern part of the Western Desert. This formation is composed of cavernous and fissured limestone, sandy limestone intercalated with marl intercalations and dolomitic limestone. It has lateral facies changes from sandy and clay to chalky marly limestone at the approach of headland (Hammad ,1972; Yousif et al., 2015). Pliocene deposits are of limited present through in the study area. These sediments are composed mainly of clay, sand and marly limestone with shale and marl intercalations. The Quaternary deposits are widely cover the surface and dominated by limestone facies that rest uncomfortably on the Tertiary deposits. These sediments are mainly represented by Pleistocene and Holocene deposits. Pleistocene deposits have also a wide distribution in the area of interest and are essentially formed of oolitic limestone that represents the essential bulk of the Pleistocene sediments. It is almost developed in the form of elongated ridges which are cross-bedded and formed of snow-white oolitic sand grains that are weakly cemented with yellow to grayish yellow color through weathering (Taha, 1973). The Pleistocene deposits are formed of oolitic limestone ridges, old lagoonal deposits, old beaches and limestone. Holocene deposits in the coastal area are formed by a variety of unconsolidated deposits as the weathered products of the Miocene and Pleistocene deposits (Yousif et al., 2014). These deposits can be differentiated into: beach deposits, Sand dune accumulations, alluvial deposits and eolian deposits Northwestern coast of Egypt is considered as a series of structurally alternating positive and negative areas with NE–SW direction. It is characterized by faults and folds. Most folds are formed during Late Cretaceous - Early Tertiary, and have NE-SW direction and agree with the Syrian Arc system trend (Shata, 1957 and Said, 1962). The majority of faults are step normal faults which have long history of growth, while the second type of faults are strike slip faults which related to the movement during the late Cretaceous. The faults have NE-SW and N-S trend . In the area of interest, 1-D geophysical survey involved the integration between vertical electrical sounding method and time domain electromagnetic (TEM) for the purpose of detecting the depth to water bearing layer, the horizontal and vertical lithological variations, the thickness of the fractured limestone water-bearing and fracture characteristics and geometry if available. A total number of 8 VES and 78 TEM soundings are carried out in the study area. Vertical electrical sounding survey is applied to a horizontally or roughly horizontally stratified earth. The Schlumberger array was applied in the field measurements with a maximum AB/2 ranging between 700 m and 1000 m. These measurements were carried out in the field by using SYSCAL JUNIOR Switch-72. The distance between each two sites is ranging from 4 to 7 km according to accessibility. Three of these electrical soundings were conducted close to known wells which provide us with some information such as well depth and the depth to water table in addition to construct a convenient initial model, as the base of quantitative interpretations. At each sounding station, the apparent electrical resistivity was measured against half the current electrode spacing (AB/2) and plotted log /log scale in the form of field resistivity sounding curve. Time Domain Electromagnetic (TEM) survey was conducted in the studied area using TEM-FAST 48 HPC with loop size 25 m, 100m and 200m according to the topography of the area. The TEM sounding stations of loop size 25m were carried out in the coastal plain area at sites close to the shoreline. TEM survey in the present study adopted a single loop configuration in which signals are transmitted and received utilizing the same loop (Fitterman and Stewart, 1986) at each station, the survey was repeated several times with different acquisition parameters to enhance the signal noise ratio and we selected the measurements with less noise for the modeling and interpretation. Interpretation of the obtained resistivity data were achieved in two approaches, qualitative and quantitative interpretation. These approaches of interpretation are used to obtain all types of countable information about the electrical properties of the subsurface layers. The main objectives of the interpretation process are; transforming the field measurements into discrete layered models and detecting the depth, thickness and resistivity of each layer. The qualitative interpretation depends on visual analytical of the resistivity sounding curves. It includes description of all curve types and makes a distribution map to compare the relative variations in the apparent resistivity and the thicknesses of the different layers detected on the sounding curves. The quantitative interpretation based on choosing an initial model from the available geological and hydrogeological information (well logging recoded). In this interpretation, the geoelectrical resistivity sounding data was carried out by using two different techniques. The first is the computer software RESIST version 1 that developed by Van Der Valpen 1988. The second method is using the obtained inversion from RESIST as initial model for the IX1D program.In quantitative interpretation of the geoelectrical resistivity sounding two geoelectrical parameters (the true resistivity and the corresponding true thickness of the geoelectrical layers) can be obtained when complete matching occurs between a measured field curve and a theoretical curve calculated from initial proposed model parameters. The VES’s data were first interpreted individually and the obtained inversion models were used as initial models for TEM data. To obtain more realistic results, a geoelectrical and TEM soundings were carried out at the same location and beside a borehole (Abu Marzooq) to increase the precise and the accuracy of the interpretation of the field data. The data of the borehole was used as a guide in the construction of the initial models in the interpretation of both the VES and the TEM data. The interpretation of VES No.1 and TEM No. 1 which are constructed at the same location show approximately the same inversion model with the number of layers, the same thickness of layers and small change in the resistivity values. According to this significant match with the outcomes of vertical electrical sounding and time domain electromagnetic sounding, the interpretation of the other VES and TEM soundings were done without using the joint inversion method. The VES results have different shapes depending on the subsurface geological formations on the study area. The qualitative interpretation of the field curves indicates that 75% of the curve types end with HK type and 25 % of them end with HQ type which associated with groundwater possibilities. It is observed that the whole curves end with regression of the resistivity values which mean that there is a layer of low resistivity such as clay, marl or argillaceous limestone under the water bearing layer. The apparent resistivity values on the first logarithmic cycle show two common trends; the first trend is characterized by increasing of the apparent resistivity values and this presented in most of the curve types. The second trend is characterized by decreasing of the apparent resistivity values with depth, which presents in VES No.5 and VES No.7. However, in these VES curves (VES No.5 and VES No.7), the highest resistivity values present in the first logarithmic cycle. This behavior indicates that the surface and near surface layers are nearly composed of hard rocks with high resistivity. The second cycle characterized by H- Type in most of all VES’es where the lowest values of resistivity present in VES No.8. In going downwards through the field curves (third cycles), it can be observed that most of the field curves terminate with K- type and Q-type that reflects homogeneity and continuous areal extension of the deep layers in the study area. The study area is characterized by three main types of field curves. These curves are KHK (VES No.3 and VES No.4), QHK (VES No.5 and VES No.7) and KHQ type which represented by 4 curves (VES No.1, VES No.2, VES No.6 and VES No.8). SUMMARY AND CONCLUSIONS 167 Based on the available geological information, the multi-layer models obtained from interpretation of the TEM curves and VES curves obtained through the geophysical survey, A total of 19 cross sections are here constructed to reflect the subsurface layering, 8 profiles are in West-East direction and 11 profiles are in South-North direction. The interpreted geoelectrical cross-sections show four geoelectrical layers. The upper layer shows resistivity ranged between 7.3 and 266Ω.m with thickness ranges from 2-30m and interpreted as surface layer. The second geoelectrical layer shows resistivity ranged between 11 and 516Ω.m and thickness ranges from 18-87m. This layer and corresponds to marly limestone to compacted limestone. The third layer shows resistivity varying between 8.8 and 40Ω.m. This layer represents the water-bearing fracture limestone. It has a thickness ranging from 15.6 to 40m. The fourth layer has low resistivity ranged between 0.4 and 9.3 Ω.m which represents clay. from the interpretation of the cross sections, it is considered that the apparent resistivity of the electrical stations have similar behaviors (lithological and hydrological conditions), but the thickness of layers changes from site to another. Geophysical data exposed that there is a groundwater reservoir in the area west El Negila. This aquifer consists of fracture limestone with brackish to fresh water. Resistivity maps show that groundwater in the southern parts of the area might be of good quality than the water in the northern parts. The most appropriate areas for drilling new water wells possess the southwestern zone of the area of study. Also, from the maps, we indicate that the groundwater fellow from the south to north in the direction of the Mediterranean Sea. Also, the resistivity distribution of the study area indicates that there is affecting from seawater intrusion which reduces the values of resistivity in the northeast direction of the study area. The obtained results from DEM analyses show that the study area consists of six main basins which have dense drainage network and parallel with main channel streaming from the tableland and flow down towards the Mediterranean Sea, consequent to general slope of land surface. These basins are covering area ranges from 73.6 km2 at W.Alsedrah (basin No. 2) to 602.6 km2 at W. Almaqtalah (basin No. 6). Through DEM analysis and ArcGIS, some parameters have been determined to the six basins in the study area. These parameters help in estimating the relative amount of surface runoff and the possibility of these basins to receive groundwater recharge for the shallow aquifer. Four of the extracted drainage basins are of the fifth stream order but basin No. 6 has sixth order while basin No. 1 has seventh order. The tableland has a dendritic drainage pattern which donating to the deficiency of the structure control and the homogeneity in texture. The total stream lengths of these extracted basins are ranging from 23.5 km at basin 4 (wadi Qatranah) to 79.3 km at basin No. 1 (wadi. Shammas). For the basin width, it is noted that basin No. 1 has the highest value (15 km) and basin No. 2 has the lowest value (6 km). The main channel slope is important for the channel slope where it is considered as assessment of the runoff volume that could be evaluated. In general the investigated area is characterized by medium to high relief and moderate topography where the main channel slope ranges from 2.86% (basin No. 1) to 5.2% (basin No. 2). Six up-sloping areas (UCA) from five basins are detected for studying the aquifer storage and recovery (ASR) strategy in the area. Each up-sloping area (UCA) ends with a point which represents a water catchment point. At each point of them there is a possibility for construction an ASR system. For testing the possibility of the Aquifer storage and recovery (ASR) system, it is necessary to detect the subsurface succession at each point, determine some morphometric parameters and estimate the surface runoff. The subsurface lithology determined using 2D electrical resistivity tomography that will be briefly discussed in the following chapters. A number of morphometric parameters are determined to these six areas to compare between them and fix the best site for ASR system. These six sub-basins (UCA) have area ranging between 16 km2 at W.Qatranh (UCA No.4) and 427.6 km2 at W. Shammas (UCA No.1). The total stream lengths of these up sloping area (UCA) are ranging between 16.6 km at basin No. 4 (Wadi Qatranah) and 75.4 km at basin No.1 (Wadi. Shammas). UCA No.4 has the lowest value of width (2.8 km) and UCA No.1 has the highest value of width (15 km). The average annual rainfall 146.14mm is used for estimating the surface runoff (Q) which depends on the curve number method through certain equations from No. 1, to No. 4. The obtained curve number value for the studied sub-basins (up sloping area) is 80 values which depend on land use, soil group, and moisture content of the studied up sloping areas. The soil cover of each UCA is identified regarding the geologic map, the field investigations and Google Earth pro software. In addition, these Up-Sloping Areas are proper bare area from cultivation & urbanization and almost dry. The studied area which fall under arid and semi-arid rangelands and of a herbaceous cover type where the area of these basins have <30% ground cover. The initial abstraction (Ia) of the area of study is about 12.7mm. The results (Table 3-4) reveal that the studied Up-Sloping Areas have actual runoff (Q) is about 90.4 mm annually. The total annual runoff volume (Qv) for an area was calculated using equation No. 5, where it varies from 1.44×106 m3 (UCA No.4) to 38.6×106 m3 (UCA No.1). The total annual runoff volume for the six UCA (total area 748.1 km2) is 67.6×106 m3. The evaluation of all these results reflects that the area of interest has runoff about 61.9% of its rainfall, while the remaining rainfall is lost by evaporation and infiltration processes. When the rainfall amounts increase, the surface runoff will increase. Hence, this percentage is considered as a very good amount for recharging the aquifer through the construction of aquifer storage and recovery system (ASR). On 12 and 14 December 2020, the heavy rains battered the study area. This heavy storm is selected to be analyzed to calculate the runoff resulting from this storm. The rainfall data is collected from the website for satellite data (GSMAP). In this storm it is shown that, the total rainfall is about 29.4mm and the actual runoff (Q) is 3.5 mm. The total runoff volume for an area (QV) ranges between 0.0056*106 m3 at point No.4 and 1.5*106 m3 in point No.1. SUMMARY AND CONCLUSIONS 171 The two dimensional electrical imaging (2D) scans the distribution of the electrical properties of subsurface layers in continuous image. This geoelectrical imaging technique was applied along seven profiles at specific seven points. Six profiles were constructed at the suggested points for testing the ASR system in five basins in the area of study. These six profiles were oriented perpendicular to the drainage lines (main channel) in west-east direction and only one has a south- north direction. The Wenner array was used to acquire 2D ERI data due to its high signal to noise ratio and the relatively good sensitivity to structures at depth when compared to other possible configurations (e.g. dipole-dipole). Electrical resistivity imaging (ERI) datasets were acquired using a Syscal Junior resistivity meter (IRIS Instruments, France) connected to a linear array of 72 electrodes with electrode spacing 10 m. Each profile is oriented in (W-E) direction and The two dimensional ERT results revealed that each profile show three zones according to the resistivity values. The intermediate resistivity (10-45) is corresponding to water bearing fracture limestone which appear at depth ranging from 40m to 60m. The zone of high resistivity is coinciding to dry limestone which found above the water bearing zone as at profile 4 and profile 6. The low resistivity zone (<10) is corresponding to clay layer which fall down the water bearing layer. Also these imaging profiles show fracture zones as in profile 1, profile 2, profile 3 and profile 5. The locations of these four profiles are good for construction the ASR system in the aoi but profile 4 and profile 6 are not suitable. Recommendations In view of the results of the present work and the concluded groundwater potential map, the following recommendations can be derived: 1. To deal with anisotropic aquifers such as fractured limestone aquifers, it is necessary to apply detailed and integrated exploration techniques. 2. Applying 2D resistivity imaging is better rather than VES& TEM methods because it is more accurate in detecting the fracture system 3. Constructing of cisterns and dams in the middle parts of the area is necessary to store surface flooded and rain water. 4. Agriculture development must be in the southern parts of the area through cultivated plants of low water consuming in addition to bearing dryness conditions. 5. The best localities for drilling water wells are located in the southern part of the area, which represents a good area for the sustainable developments 6. All the selected sites are good for future ASR installation, except UCA No.4, while Site 1 (UCA No.1) is considered the most suitable site for ASR installation in the future. 7. A detailed study of ASR system is necessary to explain the best mechanism to implement it 8. Constructing a gallery for each basin in the study area like W.Shammas gallery to save fresh water to the residents in the coastal plain area. SUMMARY AND CONCLUSIONS 173 9. Well logging, pumping test analysis and monitoring of water salinity should be carried out for each well to insure precise location of the water producing zone, to determine the proper save yield with the suitable draw down and to keep the pumping rate with the desired groundwater salinity.