Alzahraa Adel - Academia.edu (original) (raw)

Papers by Alzahraa Adel

Environmental Monitoring and Assessment, 2004

In the Nile Valley and Delta the protection of groundwater resources is high priority environment... more In the Nile Valley and Delta the protection of groundwater resources is high priority environmental concern. Many groundwater quality problems are already dispersed and may be widespread and frequent in occurrence. Examples include problems associated with the extensive application of chemical fertilizers in agricultural specially in the new reclaimed areas, leaks in sewers, septic tanks, the aggregate effects of many different points source pollution in urban areas and natural, geologically related water quality problems. A national groundwater quality monitoring has been designed and implemented based on the stepwise procedure. The national groundwater quality monitoring network is used to quantify the quality changes in long run, either caused by pollution activities or by salt water intrusion and to describe the overall current groundwater quality status on a national scale of the main aquifers. The monitoring tools and methodologies developed in this research can be used to assure protection of public health and determine the sustainability of groundwater in various purposes. This national monitoring network plays important roles for decision makers in developing the groundwater resources management plans in different aquifers systems in Egypt.

International Journal of Water Resources Development, 1989

The arable area of Egypt is confined to the Nile Valley and Delta. In order to provide for the ne... more The arable area of Egypt is confined to the Nile Valley and Delta. In order to provide for the needs of the rapidly increasing population and future agricultural requirements, all water resources in the area must be efficiently used. In the Nile Valley this can be achieved by extracting groundwater for irrigation and drainage. 1500 million m3 of groundwater are planned to be withdrawn from the Nile Valley aquifer. An interdisciplinary study was carried out in a pilot area to determine the impact of groundwater extraction and use in irrigating old lands. Results indicate that involvement of the farmers is very important and that groundwater extractions, if properly designed, are technically feasible and economically attractive.

Hydrological Processes, 1999

Journal of Geophysics and Engineering, 2011

Around the Nile Delta Branches, ancient settlements had been created and left their remains to be... more Around the Nile Delta Branches, ancient settlements had been created and left their remains to be good witness for the paleoenvironment during the Holocene time. Therefore, tracing of the defunct Canopic branch and its distributaries as well as associated environments are of great importance. Using a Schlumberger electrode configuration, well-distributed 44 vertical electrical resistivity soundings were acquired. The 1D modelling technique was applied to estimate the depth and the apparent resistivity of the interpreted geoelectrical units. Then 2D inversion was applied for the same data set using the ABIC least-squares inversion scheme. The geoelectrical cross-sections and slice maps discriminate the Upper Quaternary sequence into three geoelectrical units. The Holocene Nile mud is represented by two units: the agricultural root zone (unit 1) that is underlain by relatively thick water-saturated mud (unit 2). The Upper Pleistocene sandy aquifer is represented by irregular surface (unit 3). Two generations of defunct channels were traced out. The older channels are characterized by low sinuosity compared with younger channels. This is probably attributed to river activity due to relatively low sea level and much higher Nile discharge. The system of younger channels is characterized by broad meanders, probably as a consequence of sea-level rise and decreased gradient since the Middle Holocene.

Journal of Applied Geophysics, 2011

1D resistivity sounding and 2D resistivity imaging surveys were integrated with geological and hy... more 1D resistivity sounding and 2D resistivity imaging surveys were integrated with geological and hydrochemical data to assess the aquifer vulnerability and saltwater intrusion in the north of Nile Delta, Egypt. In the present study, the El-Gharbyia main drain was considered as a case study to map the sand bodies within the upper silt and clay aquitard. Twenty Schlumberger soundings and six 2D dipole–dipole profiles were executed along one profile close to the western side of the main drain. In addition, 14 groundwater samples and 4 surface water samples from the main drain were chemically analyzed to obtain the major and trace elements concentrations.The results from the resistivity and hydrochemical data were used to assess the protection of the groundwater aquifer and the potential risk of groundwater pollution. The inverted resistivities and thicknesses of the layers above the aquifer layer were used to estimate the integrated electrical conductivity (IEC) that can be used for quantification of aquifer vulnerability. According to the aquifer vulnerability assessment of an underlying sand aquifer, the southern part of the area is characterized by high vulnerability zone with slightly fresh to brackish groundwater and resistivity values of 11–23 Ω.m below the clay cap. The resistivity sections exhibit some sand bodies within the clay cap that lead to increase the recharging of surface waste water (650 mg/l salinity) and flushing the upper part of underlying saltwater aquifer. The region in the north has saltwater with resistivity less than 6 Ω.m and local vulnerable zones within the clay cap. The inverted 2D dipole–dipole profiles in the vulnerable zones, in combination with drilling information have allowed the identification of subsoil structure around the main drain that is highly affected by waste water.► We apply resistivity measurements to assess the aquifer vulnerability to waste water in the north of Nile Delta. ► The obtained vulnerable zones are related to sand lenses in the protective clay cap. ► These vulnerable zones are highly effected by nitrate and trace elements from surface wastewater.

Combined sedimentological, hydrogeological and geoelectrical studies were conducted to delineate ... more Combined sedimentological, hydrogeological and geoelectrical studies were conducted to delineate the hydrostratigraphy of the Central Nile Delta area and to define the locations of the clay-rich zones in the main water bearing formations. Forty four vertical electrical sounding (VES) using Schlumberger configuration were made and the data were interpreted by a computer iteration technique. The geoelectric sections reveal four subsurface layers, with increasing depth: clay, sandy clay, fine-to-medium sand, and coarse sand with gravel. The first two layers (Bilqas Formation) recorded average resistivity values ranging between 1 and 15 ohm-m, while the deepest layers, constituting the main aquifer (Mit Ghamr Formation) attained values from 22 to 100 ohm-m. At some test sites, the sandy clay layer was missing. Lenses and pockets of clays were also found locally in the main water bearing formation. Considerable lateral variations in the layer's resistivities were attributed mainly to increase of groundwater salinity from the south towards the north. Chemical data have indicated that the area can be subdivided into northern highly brackish water area (TDS values from 4000 to 10000 mg/l), central slightly brackish water area (TDS values from 1000 to 4000 mg/l) and southern fresh water area (TDS values less than 1000 mg/l). Sedimentological data, based on examining sediment samples from twenty three wells, were used to conduct a panel diagram for the Central Nile Delta area.

The Nile Delta saturated zone lies beneath several land uses which reflect variations in the aqui... more The Nile Delta saturated zone lies beneath several land uses which reflect variations in the aquifer characteristics within the delta basin. The present study investigates the scattered rural and urban areas and their environmental impacts on the water quality of the underlying semi-confined and unconfined aquifer systems. The agricultural and industrial activities also affect the groundwater quality located close to the agricultural lands and the various industrial sites, which have started to expand during the last three decades.

Isotopes in Environmental and Health Studies, 1993

Results of tritium content measurements of groundwater from western Nile delta are presented and ... more Results of tritium content measurements of groundwater from western Nile delta are presented and compared with the tritium content of the Nile according to a given model. These results indicate the dependence of the tritium concentration on the depth of well and geophysical structure of its location and also its proximity to irrigation channels.The mean residence time of the groundwater in the investigated wells ranges from a few years to several hundreds of years.A contour map of tritium concentration isolines illustrates the decrease of tritium content values in the north direction towards the Mediterranean Sea due to sea-water intrusion. The clustered tritium isoline could be attributed to mixing with other water of older recharge.Also the salinity of groundwater increased in the direction of Mediterranean Sea which points out to sea-water intrusion in the groundwater.

Environmental Earth Sciences, 2009

The sea level rise has its own-bearing on the coastal recession and hydro-environmental degradati... more The sea level rise has its own-bearing on the coastal recession and hydro-environmental degradation of the River Nile Delta. Attempts are made here to use remote sensing to detect the coastal recession in some selected parts and delineating the chemistry of groundwater aquifers and surface water, which lie along south-mid-northern and coastal zone of the Nile Delta. Eight water samples from groundwater monitoring wells and 13 water samples from surface water were collected and analyzed for various hydrochemical parameters. The groundwater samples are classified into five hydrochemical facies on Hill-Piper trilinear diagram based on the dominance of different cations and anions: facies 1: Ca–Mg–Na–HCO3–Cl–SO4 type I; facies 2: Na–Cl–HCO3 type II; facies 3: Na–Ca–Mg–Cl type III, facies 4: Ca–Na–Mg–Cl–HCO3 type IV and facies 5: Na–Mg–Cl type V. The hydrochemical facies showed that the majority of samples were enriched in sodium, bicarbonate and chloride types and, which reflected that the sea water and tidal channel play a major role in controlling the groundwater chemical composition in the Quaternary shallow aquifers, with a severe degradation going north of Nile Delta. Also, the relationship between the dissolved chloride (Cl, mmol/l), as a variable, and other major ion combinations (in mmol/l) were considered as another criterion for chemical classification system. The low and medium chloride groundwater occurs in southern and mid Nile Delta (Classes A and B), whereas the high and very high chloride (classes D and C) almost covers the northern parts of the Nile Delta indicating the severe effect of sea water intrusion. Other facets of hydro-environmental degradation are reflected through monitoring the soil degradation process within the last two decades in the northern part of Nile Delta. Land degradation was assessed by adopting new approach through the integration of GLASOD/FAO approach and Remote Sensing/GIS techniques. The main types of human induced soil degradation observed in the studied area are salinity, alkalinity (sodicity), compaction and water logging. On the other hand, water erosion because of sea rise is assessed. Multi-dates satellite data from Landsat TM and ETM+ images dated 1983 and 2003 were used to detect the changes of shoreline during the last two decades. The obtained results showed that, the eroded areas were determined as 568.20 acre; meanwhile the accreted areas were detected as 494.61 acre during the 20-year period.

The Nile Delta aquifer is among the largest groundwater reservoirs in the world. Along its northe... more The Nile Delta aquifer is among the largest groundwater reservoirs in the world. Along its northern boundary, the aquifer is in direct hydraulic contact with the Mediterranean sea. Due to the excessive pumping over the last few decades, the groundwater quality in the northern parts of the Delta has been deteriorated considerably. This paper presents various simulation scenarios for the seawater intrusion problem in the Nile Delta aquifer. Two models, 2D-FED and SUTRA, are used to simulate the problem in the vertical and horizontal sections, respectively. The 2D-FED model is employed to simulate the current conditions and predict the effect of the water level rise in the Mediterranean sea under the condition of global warming. A 50 cm rise in the seawater level is expected to cause about 4.5 km inland migration of equiconcentration line 1. SUTRA is used to define the best location for additional groundwater pumping from the Nile Delta aquifer. It is concluded that any additional pumping should be practiced in the middle Delta and pumping from the eastern and western parts should be reduced.

Environmental Monitoring and Assessment, 2004

In the Nile Valley and Delta the protection of groundwater resources is high priority environment... more In the Nile Valley and Delta the protection of groundwater resources is high priority environmental concern. Many groundwater quality problems are already dispersed and may be widespread and frequent in occurrence. Examples include problems associated with the extensive application of chemical fertilizers in agricultural specially in the new reclaimed areas, leaks in sewers, septic tanks, the aggregate effects of many different points source pollution in urban areas and natural, geologically related water quality problems. A national groundwater quality monitoring has been designed and implemented based on the stepwise procedure. The national groundwater quality monitoring network is used to quantify the quality changes in long run, either caused by pollution activities or by salt water intrusion and to describe the overall current groundwater quality status on a national scale of the main aquifers. The monitoring tools and methodologies developed in this research can be used to assure protection of public health and determine the sustainability of groundwater in various purposes. This national monitoring network plays important roles for decision makers in developing the groundwater resources management plans in different aquifers systems in Egypt.

International Journal of Water Resources Development, 1989

The arable area of Egypt is confined to the Nile Valley and Delta. In order to provide for the ne... more The arable area of Egypt is confined to the Nile Valley and Delta. In order to provide for the needs of the rapidly increasing population and future agricultural requirements, all water resources in the area must be efficiently used. In the Nile Valley this can be achieved by extracting groundwater for irrigation and drainage. 1500 million m3 of groundwater are planned to be withdrawn from the Nile Valley aquifer. An interdisciplinary study was carried out in a pilot area to determine the impact of groundwater extraction and use in irrigating old lands. Results indicate that involvement of the farmers is very important and that groundwater extractions, if properly designed, are technically feasible and economically attractive.

Hydrological Processes, 1999

Journal of Geophysics and Engineering, 2011

Around the Nile Delta Branches, ancient settlements had been created and left their remains to be... more Around the Nile Delta Branches, ancient settlements had been created and left their remains to be good witness for the paleoenvironment during the Holocene time. Therefore, tracing of the defunct Canopic branch and its distributaries as well as associated environments are of great importance. Using a Schlumberger electrode configuration, well-distributed 44 vertical electrical resistivity soundings were acquired. The 1D modelling technique was applied to estimate the depth and the apparent resistivity of the interpreted geoelectrical units. Then 2D inversion was applied for the same data set using the ABIC least-squares inversion scheme. The geoelectrical cross-sections and slice maps discriminate the Upper Quaternary sequence into three geoelectrical units. The Holocene Nile mud is represented by two units: the agricultural root zone (unit 1) that is underlain by relatively thick water-saturated mud (unit 2). The Upper Pleistocene sandy aquifer is represented by irregular surface (unit 3). Two generations of defunct channels were traced out. The older channels are characterized by low sinuosity compared with younger channels. This is probably attributed to river activity due to relatively low sea level and much higher Nile discharge. The system of younger channels is characterized by broad meanders, probably as a consequence of sea-level rise and decreased gradient since the Middle Holocene.

Journal of Applied Geophysics, 2011

1D resistivity sounding and 2D resistivity imaging surveys were integrated with geological and hy... more 1D resistivity sounding and 2D resistivity imaging surveys were integrated with geological and hydrochemical data to assess the aquifer vulnerability and saltwater intrusion in the north of Nile Delta, Egypt. In the present study, the El-Gharbyia main drain was considered as a case study to map the sand bodies within the upper silt and clay aquitard. Twenty Schlumberger soundings and six 2D dipole–dipole profiles were executed along one profile close to the western side of the main drain. In addition, 14 groundwater samples and 4 surface water samples from the main drain were chemically analyzed to obtain the major and trace elements concentrations.The results from the resistivity and hydrochemical data were used to assess the protection of the groundwater aquifer and the potential risk of groundwater pollution. The inverted resistivities and thicknesses of the layers above the aquifer layer were used to estimate the integrated electrical conductivity (IEC) that can be used for quantification of aquifer vulnerability. According to the aquifer vulnerability assessment of an underlying sand aquifer, the southern part of the area is characterized by high vulnerability zone with slightly fresh to brackish groundwater and resistivity values of 11–23 Ω.m below the clay cap. The resistivity sections exhibit some sand bodies within the clay cap that lead to increase the recharging of surface waste water (650 mg/l salinity) and flushing the upper part of underlying saltwater aquifer. The region in the north has saltwater with resistivity less than 6 Ω.m and local vulnerable zones within the clay cap. The inverted 2D dipole–dipole profiles in the vulnerable zones, in combination with drilling information have allowed the identification of subsoil structure around the main drain that is highly affected by waste water.► We apply resistivity measurements to assess the aquifer vulnerability to waste water in the north of Nile Delta. ► The obtained vulnerable zones are related to sand lenses in the protective clay cap. ► These vulnerable zones are highly effected by nitrate and trace elements from surface wastewater.

Combined sedimentological, hydrogeological and geoelectrical studies were conducted to delineate ... more Combined sedimentological, hydrogeological and geoelectrical studies were conducted to delineate the hydrostratigraphy of the Central Nile Delta area and to define the locations of the clay-rich zones in the main water bearing formations. Forty four vertical electrical sounding (VES) using Schlumberger configuration were made and the data were interpreted by a computer iteration technique. The geoelectric sections reveal four subsurface layers, with increasing depth: clay, sandy clay, fine-to-medium sand, and coarse sand with gravel. The first two layers (Bilqas Formation) recorded average resistivity values ranging between 1 and 15 ohm-m, while the deepest layers, constituting the main aquifer (Mit Ghamr Formation) attained values from 22 to 100 ohm-m. At some test sites, the sandy clay layer was missing. Lenses and pockets of clays were also found locally in the main water bearing formation. Considerable lateral variations in the layer's resistivities were attributed mainly to increase of groundwater salinity from the south towards the north. Chemical data have indicated that the area can be subdivided into northern highly brackish water area (TDS values from 4000 to 10000 mg/l), central slightly brackish water area (TDS values from 1000 to 4000 mg/l) and southern fresh water area (TDS values less than 1000 mg/l). Sedimentological data, based on examining sediment samples from twenty three wells, were used to conduct a panel diagram for the Central Nile Delta area.

The Nile Delta saturated zone lies beneath several land uses which reflect variations in the aqui... more The Nile Delta saturated zone lies beneath several land uses which reflect variations in the aquifer characteristics within the delta basin. The present study investigates the scattered rural and urban areas and their environmental impacts on the water quality of the underlying semi-confined and unconfined aquifer systems. The agricultural and industrial activities also affect the groundwater quality located close to the agricultural lands and the various industrial sites, which have started to expand during the last three decades.

Isotopes in Environmental and Health Studies, 1993

Results of tritium content measurements of groundwater from western Nile delta are presented and ... more Results of tritium content measurements of groundwater from western Nile delta are presented and compared with the tritium content of the Nile according to a given model. These results indicate the dependence of the tritium concentration on the depth of well and geophysical structure of its location and also its proximity to irrigation channels.The mean residence time of the groundwater in the investigated wells ranges from a few years to several hundreds of years.A contour map of tritium concentration isolines illustrates the decrease of tritium content values in the north direction towards the Mediterranean Sea due to sea-water intrusion. The clustered tritium isoline could be attributed to mixing with other water of older recharge.Also the salinity of groundwater increased in the direction of Mediterranean Sea which points out to sea-water intrusion in the groundwater.

Environmental Earth Sciences, 2009

The sea level rise has its own-bearing on the coastal recession and hydro-environmental degradati... more The sea level rise has its own-bearing on the coastal recession and hydro-environmental degradation of the River Nile Delta. Attempts are made here to use remote sensing to detect the coastal recession in some selected parts and delineating the chemistry of groundwater aquifers and surface water, which lie along south-mid-northern and coastal zone of the Nile Delta. Eight water samples from groundwater monitoring wells and 13 water samples from surface water were collected and analyzed for various hydrochemical parameters. The groundwater samples are classified into five hydrochemical facies on Hill-Piper trilinear diagram based on the dominance of different cations and anions: facies 1: Ca–Mg–Na–HCO3–Cl–SO4 type I; facies 2: Na–Cl–HCO3 type II; facies 3: Na–Ca–Mg–Cl type III, facies 4: Ca–Na–Mg–Cl–HCO3 type IV and facies 5: Na–Mg–Cl type V. The hydrochemical facies showed that the majority of samples were enriched in sodium, bicarbonate and chloride types and, which reflected that the sea water and tidal channel play a major role in controlling the groundwater chemical composition in the Quaternary shallow aquifers, with a severe degradation going north of Nile Delta. Also, the relationship between the dissolved chloride (Cl, mmol/l), as a variable, and other major ion combinations (in mmol/l) were considered as another criterion for chemical classification system. The low and medium chloride groundwater occurs in southern and mid Nile Delta (Classes A and B), whereas the high and very high chloride (classes D and C) almost covers the northern parts of the Nile Delta indicating the severe effect of sea water intrusion. Other facets of hydro-environmental degradation are reflected through monitoring the soil degradation process within the last two decades in the northern part of Nile Delta. Land degradation was assessed by adopting new approach through the integration of GLASOD/FAO approach and Remote Sensing/GIS techniques. The main types of human induced soil degradation observed in the studied area are salinity, alkalinity (sodicity), compaction and water logging. On the other hand, water erosion because of sea rise is assessed. Multi-dates satellite data from Landsat TM and ETM+ images dated 1983 and 2003 were used to detect the changes of shoreline during the last two decades. The obtained results showed that, the eroded areas were determined as 568.20 acre; meanwhile the accreted areas were detected as 494.61 acre during the 20-year period.

The Nile Delta aquifer is among the largest groundwater reservoirs in the world. Along its northe... more The Nile Delta aquifer is among the largest groundwater reservoirs in the world. Along its northern boundary, the aquifer is in direct hydraulic contact with the Mediterranean sea. Due to the excessive pumping over the last few decades, the groundwater quality in the northern parts of the Delta has been deteriorated considerably. This paper presents various simulation scenarios for the seawater intrusion problem in the Nile Delta aquifer. Two models, 2D-FED and SUTRA, are used to simulate the problem in the vertical and horizontal sections, respectively. The 2D-FED model is employed to simulate the current conditions and predict the effect of the water level rise in the Mediterranean sea under the condition of global warming. A 50 cm rise in the seawater level is expected to cause about 4.5 km inland migration of equiconcentration line 1. SUTRA is used to define the best location for additional groundwater pumping from the Nile Delta aquifer. It is concluded that any additional pumping should be practiced in the middle Delta and pumping from the eastern and western parts should be reduced.