Abdelfattah et al. (2025) Synergistic Use of Remote Sensing, Geophysics, and Hydrogeology for Sustainable Groundwater Management in Arid Landscapes

Identification

• Journal: Earth Systems and Environment
• Year: 2025
• Date: 2025-12-12
• Authors: Mohamed Abdelfattah, Ahmed Gaber, Mohamed H. Geriesh, Zoltan Szantoi, Mariam Hassan Sheta
• DOI: 10.1007/s41748-025-00954-y

Research Groups

• European Space Agency (ESA-ESRIN), Science, Applications & Climate Department, Frascati, Italy
• EDYTEM, Université Savoie Mont-Blanc, Le Bourget du Lac, France
• Port Said University, Faculty of Science, Geology Department and Environmental Sciences Department, Port Said, Egypt
• Suez Canal University, Faculty of Science, Geology Department, Ismailia, Egypt
• Stellenbosch University, Department of Geography & Environmental Studies, Stellenbosch, South Africa

Short Summary

This research assesses the groundwater potential and aquifer characteristics in Egypt's Gallaba Plain using an integrated approach of remote sensing, geophysics, and hydrogeology. It identifies two highly productive, semi-confined Nubian Sandstone aquifers with significant potential for agricultural and urban use, despite the brackish water quality requiring managed application.

Objective

• To evaluate the surface geomorphological features of the Gallaba Plain.
• To identify areas with high potential for groundwater recharge.
• To determine the petrophysical and hydrogeological properties of the aquifers.
• To map aquifer parameters to comprehensively assess groundwater potentiality in the Gallaba Plain, Western Desert, Egypt.

Study Configuration

• Spatial Scale: Gallaba Plain, south-western desert of Egypt, covering 2370 km². Borehole investigations extended to approximately 450 m depth.
• Temporal Scale: Sentinel-2 imagery from 2020 and 2025 was used for vegetation cover change analysis. Pumping tests and data collection were conducted as part of the study, with groundwater exploration in the area noted since 2013.

Methodology and Data

• Models used:
  • Analytical Hierarchy Process (AHP) for weighting thematic layers.
  • Weighted Linear Combination (WLC) for groundwater potential mapping.
  • Archie (1942) formula for formation water resistivity.
  • Schlumberger (1972, 1984) equations for true resistivity, shale volume, and effective porosity.
  • Humble formula and Archie formation factor for total porosity.
  • Jorgensen (1988) method for permeability.
  • Jacob’s method (1947) and Theis method (1935) for hydraulic parameters (hydraulic conductivity, transmissivity, storativity) from pumping tests.
  • Kriging interpolation for mapping petrophysical and hydrogeological properties.
  • Sen2Cor program for atmospheric correction of Sentinel-2 data.
  • Strahler’s stream order approach for drainage pattern analysis.
  • Aquifer Test software for pumping test evaluation.
• Data sources:
  • Remote Sensing: Sentinel-2 imagery (European Space Agency) for Land Use/Land Cover (LULC) and Normalized Difference Vegetation Index (NDVI); Copernicus Digital Elevation Model (DEM) (30 m resolution) for topographic variables (elevation, slope, aspect, hillshade, flow direction, flow accumulation, stream pattern, drainage density).
  • Geophysical: Gamma-Ray, Self-Potential, and Electrical Resistivity logs from 8 wells (up to 450 m depth), digitized using Didger Software.
  • Hydrogeological: Step and continuous pumping tests from 8 wells; geological maps (Geological Survey of Egypt); hydraulic head data; yearly precipitation rates (https://chrsdata.eng.uci.edu/).
  • Validation Data: 44 existing wells for statistical validation of the groundwater potential map.

Main Results

• Groundwater Potential: The AHP-based model (Consistency Ratio = 0.06, AUC = 0.84) identified that over 47% of the Gallaba Plain has high to very high groundwater potential. Very high potential zones (20.1%) are concentrated in the northeastern and southeastern regions, characterized by permeable Nubian Sandstone and Quaternary alluvium, minimal relief, and significant flow accumulation.
• Aquifer Identification: Two semi-confined aquifers were identified within the Nubian Sandstone formation:
  • Upper Aquifer (Aquifer 1): Thickness 25-70 m; shale volume 15-24%; formation water resistivity 1.5-2.6 Ω·m; total porosity 39-44%; effective porosity 20-31%; permeability 8.78 × 10⁻¹³ to 2.00 × 10⁻¹² m² (average 1.437 × 10⁻¹² m²); hydraulic conductivity 2.26 × 10⁻⁴ to 7.58 × 10⁻⁴ m/s (average 4.62 × 10⁻⁴ m/s); transmissivity 7.93 × 10⁻³ to 1.98 × 10⁻² m²/s (average 1.56 × 10⁻² m²/s); storativity 8.32 × 10⁻⁴ to 1.5 × 10⁻¹.
  • Lower Aquifer (Aquifer 2): Thickness 15-125 m; shale volume 19-25%; formation water resistivity 1.7-2.5 Ω·m; total porosity 41-45%; effective porosity 23-34%; permeability 1.08 × 10⁻¹² to 1.97 × 10⁻¹² m² (average 1.65 × 10⁻¹² m²); hydraulic conductivity 4.40 × 10⁻⁵ to 8.39 × 10⁻⁴ m/s (average 3.00 × 10⁻⁴ m/s); transmissivity 2.15 × 10⁻³ to 3.37 × 10⁻² m²/s (average 1.85 × 10⁻² m²/s); storativity 9.5 × 10⁻³ to 1.14 × 10⁻¹.
• Groundwater Quality: Both aquifers contain brackish water. Total Dissolved Solids (TDS) in the upper aquifer range from 1440 to 4500 mg/L (average 2500 mg/L), and in the lower aquifer from 1150 to 2170 mg/L (average 1550 mg/L). This water is generally unsuitable for direct human consumption and requires careful management for irrigation, primarily for moderately to very salt-tolerant crops.
• Recharge: Localized recharge occurs in wadis and depressions, but the primary source is leakage from the Nile River, indicated by a hydraulic gradient from west to east.

Contributions

• Presents the first integrated assessment of groundwater resources in Egypt’s Gallaba Plain, combining remote sensing, geophysical well logging, and hydrogeological pumping tests, thereby filling a critical data gap.
• Provides a comprehensive and quantitative characterization of aquifer petrophysical and hydraulic properties, moving beyond previous qualitative summaries.
• Offers a validated groundwater potential map and detailed aquifer parameters, serving as a pragmatic framework for strategic well placement and sustainable groundwater development in arid regions.
• Proposes a generalizable multidisciplinary methodology for aquifer evaluation applicable to other dry and semi-arid regions globally with similar hydrogeological characteristics.
• Highlights the critical role of integrated surface and subsurface data for informed water resource planning and management in the face of increasing climate and anthropogenic pressures.

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Citation

@article{Abdelfattah2025Synergistic,
  author = {Abdelfattah, Mohamed and Gaber, Ahmed and Geriesh, Mohamed H. and Szantoi, Zoltan and Sheta, Mariam Hassan},
  title = {Synergistic Use of Remote Sensing, Geophysics, and Hydrogeology for Sustainable Groundwater Management in Arid Landscapes},
  journal = {Earth Systems and Environment},
  year = {2025},
  doi = {10.1007/s41748-025-00954-y},
  url = {https://doi.org/10.1007/s41748-025-00954-y}
}