Papers by Mohamed El Alfy
Sustainability
The global exponential rise in greenhouse gas (GHG) emissions over the last few decades has trigg... more The global exponential rise in greenhouse gas (GHG) emissions over the last few decades has triggered an urgent need to contextualize low-cost and evergreen technologies for restraining GHG production and enhancing soil carbon sink. GHGs can be mitigated via incorporating biochar into soil matrix to sequestrate the mineralized carbon in a stable form upon organic matter decomposition in soil. However, the efficiency of using biochar to offset GHG emissions from soil and terrestrial ecosystems is still debatable. Moreover, in the literature, biochar shows high functionality in restraining GHG emissions in short-term laboratory studies, but it shows minimal or negative impacts in field-scale experiments, leading to conflicting results. This paper synthesizes information on the ability of biochar to mitigate carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions from soil and organic biomass, with an emphasis on cropland soils. The feedstock type, pyrolysis temperature,...
Environmental Earth Sciences, Apr 18, 2013
Groundwater contamination is one of the most significant problems in arid countries. Al-Quwiy'yia... more Groundwater contamination is one of the most significant problems in arid countries. Al-Quwiy'yia region is an example of an area where the groundwater is contaminated as a result of infiltration of waste water in low-lying areas adjacent to inhabited zones. Such contamination poses significant environmental threats for the surrounding environment and groundwater. Surface observations and spatial distribution of contamination observed in the shallow aquifer indicate that the main contamination sources were from sewage as well as from waste water dumping. However, the main source of water supply for the whole area is groundwater abstracted from the relatively shallow aquifer. Therefore, the transient electromagnetic method (TEM) and 2D electrical resistivity tomography (2D ERT) have been applied close to the waste water dump site to characterize the response of pollution plumes. Both of these geoelectrical techniques are sensitive to electrical conductivity as well as to other physical properties, which are greatly influenced by the polluted groundwater. Therefore, it is possible to profile the contamination plumes, both vertically and horizontally, in the vicinity of the measured stations. The ERT profiles gave detailed information about the lateral distribution of the contaminated groundwater, whereas the TEM demonstrated the vertical extensions.
DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2010
Groundwater is endangered by agricultural activities, wastes disposal, aquifer over exploitation ... more Groundwater is endangered by agricultural activities, wastes disposal, aquifer over exploitation and seawater intrusion. The pollution risk is high, as the depth to the water table is shallow and the aquifers are highly permeable and have poor buffering capacity. Intensive farming activities have also put stress on groundwater quality due to intensive use of fertilizers and pesticides. As a result, concentrations of NO3-, SO4 2and PO4-2 are very high. Most of the house owners do not have access to public sewers, which poses another risk for the aquifers. More than 71.2% of the aerial distribution of nitrate concentration is greater than 44.29 mg/L, thus causing a serious problem. Static water level maps from 1983 to 2000 show the declining of the water level with time. The discharge from Quaternary aquifers exceeds the recharge rates after 1988 resulting in both upward leakage of the deeper high saline water and seawater intrusion. Factor analyses were used to define the factors that affect the groundwater quality. Dissolution and deposition of several minerals, evaporation from the groundwater, human impact on the aquifers, cation exchange, mixing between different waters and rainfall recharge were identified as the main factors impacting the ground waters.
Información del artículo Hydrochemical relarionships and geochemical modeling of ground water in ... more Información del artículo Hydrochemical relarionships and geochemical modeling of ground water in al arish area, nort Sinai, Egypt.
Environmental Research, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Environmental Pollution, 2017
Rapid economic expansion poses serious problems for groundwater resources in arid areas, which ty... more Rapid economic expansion poses serious problems for groundwater resources in arid areas, which typically have high rates of groundwater depletion. In this study, integration of hydrochemical investigations involving chemical and statistical analyses are conducted to assess the factors controlling hydrochemistry and potential pollution in an arid region. Fifty-four groundwater samples were collected from the Dhurma aquifer in Saudi Arabia, and twenty-one physicochemical variables were examined for each sample. Spatial patterns of salinity and nitrate were mapped using fitted variograms. The nitrate spatial distribution shows that nitrate pollution is a persistent problem affecting a wide area of the aquifer. The hydrochemical investigations and cluster analysis reveal four significant clusters of groundwater zones. Five main factors were extracted, which explain >77% of the total data variance. These factors indicated that the chemical characteristics of the groundwater were influenced by rock ewater interactions and anthropogenic factors. The identified clusters and factors were validated with hydrochemical investigations. The geogenic factors include the dissolution of various minerals (calcite, aragonite, gypsum, anhydrite, halite and fluorite) and ion exchange processes. The anthropogenic factors include the impact of irrigation return flows and the application of potassium, nitrate, and phosphate fertilizers. Over time, these anthropogenic factors will most likely contribute to further declines in groundwater quality.
Environmental Earth Sciences, 2017
DRASTIC indexing and integrated electrical conductivity (IEC) modeling are approaches for assessi... more DRASTIC indexing and integrated electrical conductivity (IEC) modeling are approaches for assessing aquifer vulnerability to surface pollution. DRASTIC indexing is more common, but IEC modeling is faster and more cost-effective because it requires less data and fewer processing steps. This study aimed to compare DRASTIC indexing with IEC modeling to determine whether the latter is sufficient on its own. Both approaches are utilized to determine zones vulnerable to groundwater pollution in the Nile Delta. Hence, assessing the nature and degree of risk are important for realizing effective measures toward damage minimization. For DRASTIC indexing, hydrogeological factors such as depth to aquifer, recharge rate, aquifer media, soil permeability, topography, impact of the vadose zone, and hydraulic conductivity were combined in a geographical information system environment for assessing the aquifer vulnerability. For IEC modeling, DC resistivity data were collected from 36 surface sounding points to cover the entire area and used to estimate the IEC index. Additionally, the vulnerable zones identified by both approaches were tested using a local-scale resistivity survey in the form of 1D and 2D resistivity imaging to determine the permeable pathways in the vadose zone. A correlation of 0.82 was obtained between the DRASTIC indexing and IEC modeling results. For additional benefit, the obtained DRASTIC and IEC models were used together to develop a vulnerability map. This map showed a very high vulnerability zone, a high-vulnerability zone, and moderate-and low-vulnerability zones constituting 19.89, 41, 27, and 12%, respectively, of the study area. Identifying where groundwater is more vulnerable to pollution enables more effective protection and management of groundwater resources in vulnerable areas.
Environmental science and pollution research international, Jan 26, 2014
Spatial characteristics of the properties (dust organic material and pH), concentrations, and enr... more Spatial characteristics of the properties (dust organic material and pH), concentrations, and enrichment levels of toxic metals (Ni, Hg, Mn and As) in street dust from Xiandao District (Middle China) were investigated. Method of incorporating receptor population density into noncarcinogenic health risk assessment based on local land use map and geostatistics was developed to identify their priority pollutants/regions of concern. Mean enrichment factors of studied metals decreased in the order of Hg ≈ As > Mn > Ni. For noncarcinogenic effects, the exposure pathway which resulted in the highest levels of exposure risk for children and adults was ingestion except Hg (inhalation of vapors), followed by dermal contact and inhalation. Hazard indexes (HIs) for As, Hg, Mn, and Ni to children and adults revealed the following order: As > Hg > Mn > Ni. Mean HI for As exceeded safe level (1) for children, and the maximum HI (0.99) for Hg was most approached the safe level. Prior...
International Journal of Environmental Science and Technology, 2017
Saudi Arabia is a huge area with diverse climatic and topographical features. This diversity in c... more Saudi Arabia is a huge area with diverse climatic and topographical features. This diversity in climate is augmented by seasonal weather variations. The study discusses solar irradiance and sunshine duration in terms of seasonal weather systems. Sunshine duration and solar irradiance maps show that the East Mediterranean weather systems (such as Cyprus low) in winter affect the majority of the geographical regions in Saudi Arabia. In spring and autumn, Sudan low becomes more active than Cyprus low, especially in the west and central regions. Sunshine duration in April is 47% compared to 50% in January. Sunshine duration in the southwest region is affected by the rainy and wet summer monsoon which reduces sunshine duration to 33% in summer (July), while it is 43% in winter (January). In addition, the study uses the Angstrom equation to estimate solar irradiance. The absolute relative error between estimated and observed solar irradiance ranges between 2 and 10% in the majority of cases, with a few cases exceeding 13%.
Scientific Reports, 2019
the Umm er Radhuma (UeR) Formation is a major karst aquifer in saudi Arabia. this study investiga... more the Umm er Radhuma (UeR) Formation is a major karst aquifer in saudi Arabia. this study investigated the hydraulic and petrophysical characteristics of the folded UeR carbonate aquifer using integrated hydrological and geophysical logging datasets to understand its complex hydraulic setting as well as detect possible water flow. Petrophysical analysis showed that the UER aquifer has three zones with different lithologic and hydraulic properties. The upper zone attains the best properties with average values of 20%, >100 mD, 3.30 × 10 −5-1.34 × 10 −3 m/s, and 1.49 × 10 −3-6.04 × 10 −2 m 2 /s, with respect to effective porosity, permeability, hydraulic conductivity and transmissivity. The gammaray logs indicate a good fracture system near the upper zone of the UeR Formation. pumping test measurements of transmissivity, hydraulic conductivity and storage coefficients were matched with those from geophysical logs and found to be within the expected range for confined and leaky aquifers. Hydrogeological properties were mapped to detect possible groundwater flow in relation to the dominant structure. the underground water of the folded UeR aquifer was forced along meandering flow patterns from WE to SW-NE through the anticlinal axes. The integrated approach can be further used to enhance local aquifer models and improve strategies for identifying the most productive zones in similar aquifer systems. Groundwater is considered among the most treasured natural resources, particularly in arid areas. Hydraulic conductivity (K), transmissivity (T), and storage coefficient (S) are key parameters for evaluation of aquifers. Aquifer parameters can be determined using pumping tests, which are costly and only provide local results. Heterogeneity of aquifer sediments, complex geologic settings, and multipart boundaries spatially and temporarily influence aquifer hydraulic parameters 1,2. However, it is difficult to efficiently characterize these parameters in different aquifer zones. A precise image of the aquifer can be achieved using an integrated approach in which well logging and pumping test data are conjointly interpreted. Carbonate aquifers have significant secondary porosity because of fractures and solution cavities. They have anisotropic performance because of the consequence of preferential flows through bedding plane fractures and joints, particularly in folded rocks. The magnitude of the aquifer anisotropy depends on the density and spacing of joints which cut across the bedding plain. In these carbonate aquifers, directions of groundwater flow may be difficult to predict, because of their anisotropic nature and existing geologic structures. Groundwater flow may not be perpendicular to lines of equipotential, particularly in karstic areas where conduit systems may act. The directions of maximum and medium K conform to the strike and dip of bedding, respectively, while the minimum K direction is perpendicular to bedding 3. To estimate aquifer hydraulic parameters, different pumping test methods are used; however, long-duration, step pumping, and recovery tests can be used. Estimation of aquifer hydraulic parameters is affected by aquifer stratigraphic position (unconfined, confined, leaky, and partial penetration
Hydrology Research, 2016
This study uses an integrated approach, bringing together geographic information system (GIS), re... more This study uses an integrated approach, bringing together geographic information system (GIS), remote sensing, and rainfall–runoff modeling, to assess the urbanization impact on flash floods in arid areas. Runoff modeling was carried out as a function of the catchment characteristics and the maximum daily rainfall parameters. Land-use types were extracted from the supervised classification of SPOT-5 (2010) and Landsat-8 (2015) satellite images and were validated during field checks. Catchment morphometric characteristics were carried out using the correlated Topaz and Arc-Hydro tools. Maximum floods of the catchment were evaluated by coupling GIS and remote sensing with Hydrologic Engineering Center–Hydrologic Modeling System (HEC-HMS) hydrologic modeling. Peak discharges were estimated, and the abstraction losses were computed for different return periods. The model results were calibrated according to actual runoff event. The research shows that rapid urbanization adversely affect...
Journal of African Earth Sciences, 2015
Saudi Arabia's dependence on oil and gas to generate electricity and to desalinate sea water ... more Saudi Arabia's dependence on oil and gas to generate electricity and to desalinate sea water is widely perceived to be economically and politically unsustainable. A recent business as usual simulation concluded that the Kingdom would become an oil importer by 2038. There is an opportunity for the country to over come this problem by using its geothermal energy resources. The heat flow and heat generation values of the granites spread over a cumulative area of 161,467 sq. km and the regional stress regime over the western Saudi Arabian shield strongly suggest that this entire area is potential source of energy to support 1) electricity generation, 2) fresh water generation through desalination and 3) extensive agricultural activity for the next two decades. The country can adopt a policy to harness this vast untapped enhanced geothermal systems (EGS) to mitigate climate and fresh water related issues and increase the quantity of oil for export. The country has inherent expertise to develop this resource.
Water Resources Management, 2015
In arid areas, groundwater quality is an important concern for human life and natural ecosystems.... more In arid areas, groundwater quality is an important concern for human life and natural ecosystems. Rapid economic development impacts greatly on limited groundwater resources. This study examines the impacts of natural and anthropogenic contaminations on groundwater quality by integrating hydrochemical investigations, GIS and multivariate geostatistical techniques. Major and trace elements in groundwater were analyzed to evaluate the shallow alluvial aquifer connected to the fractured basement aquifer in the Jazan area of Saudi Arabia (KSA). Results show that the groundwater of the aquifer inland is generally under free conditions and is declining with time, while in the coastal areas, there is a disturbance of the groundwater balance resulting in upward leakage of deep saline water and seawater intrusion. Groundwater types are varied from calcium bicarbonate to sodium chloride, reflecting meteoric water recharge to seawater influence. The pollution risk is high, since the water table is shallow and the aquifers are highly permeable. Urbanization has put stress on groundwater quality due to wastewater contamination from pit latrines and leakage from the unrehabilitated sewage system. Chemical equilibrium and saturation indices were calculated, showing that most of the water samples were under-saturated with respect to anhydrate, aragonite, calcite, dolomite, gypsum and halite mineral phases. This affects carbonate and evaporite minerals in the aquifer, causing ground subsidence and sinkholes in the coastal area. Factor and cluster Water Resour Manage
Water Environment Research, 2013
This study aims to investigate groundwater geochemical characteristics, and to assess the effects... more This study aims to investigate groundwater geochemical characteristics, and to assess the effects of groundwater contamination in northwest Sinai, Egypt. A geographic information system, geochemical modeling, and statistical analyses tools were used. Twenty-five groundwater samples from a Quaternary aquifer were sampled. These water samples were analyzed for major, minor, and trace elements. The results of this study contribute to a better understanding of the hydrochemical characteristic as well as the anthropogenic processes of groundwater pollution. On the basis of these analyses, the geochemical parameters and the anomalous concentration of different elements enable the characterization of salinity sources of the brackish waters and the suspected sources of polluted water. Pollution sources are represented by waste disposal and agricultural activities as well as the probable upward leakage of highly saline water from the deeper aquifers and the saltwater intrusion. Pollution risk is high when the depth of the water table is shallow (0.3 to 15.0 m) and the aquifer has high hydraulic conductivity and poor matrix buffering capacity. Water Environ. Res., 85, 211 (2013).
Hydrology, 2021
In arid areas, flashflood water management is a major concern due to arid climate ambiguity. The ... more In arid areas, flashflood water management is a major concern due to arid climate ambiguity. The examining and derivation of intensity–duration–frequency (IDF) curves in an urban arid area under a variety of terrain patterns and climatic changes is anticipated. Several flood events have been reported in the Al-Lith region of western Saudi Arabia that took away many lives and caused disruption in services and trade. To find and examine the extremities and IDF curves, daily rainfall data from 1966 to 2018 is used. The IDF curves are created for a variety of return periods and climate scenarios in three terrain variabilities. This research examines various distributions to estimate the maximum rainfall for several metrological stations with varying return periods and terrain conditions. Three main zones are identified based on ground elevation variability and IDF distributions from upstream in the eastern mountainous area to downstream in the western coastal area. These IDF curves can ...
Journal of Applied …, 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 qua...
Información del artículo Hydrochemical relarionships and geochemical modeling of ground water in ... more Información del artículo Hydrochemical relarionships and geochemical modeling of ground water in al arish area, nort Sinai, Egypt.
Environmental monitoring and assessment, Jan 12, 2018
Groundwater is the key for life in arid areas. Aquifer overexploitation and climatic conditions c... more Groundwater is the key for life in arid areas. Aquifer overexploitation and climatic conditions can significantly deteriorate groundwater quality. The Al-Qassim area in central Saudi Arabia is characterized by dense agricultural use and is irrigated mainly by fossil groundwater from the Saq Aquifer. Understanding the area's hydrochemistry, major factors governing groundwater quality, and alternative uses of the groundwater are the main goals of this study. Groundwater samples were collected and examined for major, minor, and trace elements. Ionic relationships, hydrochemical facies, geospatial distributions, and multivariate analyses were conducted to assess the hydrochemical processes at play. The salinity and nitrate concentrations of the Saq Aquifer's groundwater were found to increase in the outcrop areas more than the confined areas. The spatial distributions were fragmented by three main factors: (i) modern recharge by relatively brackish water, (ii) irrigation return ...
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Papers by Mohamed El Alfy