Hussein et al. (2026) Hydrogeophysical characterization and recharge potential of three Wadi basins along the Red Sea Margin, Northeastern Desert, Egypt

Identification

• Journal: Scientific Reports
• Year: 2026
• Date: 2026-02-27
• Authors: Mahmoud Hussein, Sultan A.S. Araffa, Mahmoud Ahmed Abbas, Mahmoud S. Sharkawy
• DOI: 10.1038/s41598-026-37853-9

Research Groups

• Geology Department, Faculty of Science, Assiut Branch, Al-Azhar University, Assiut, Egypt
• National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Cairo, Egypt
• Department of Earth, Environmental and Resources Sciences (DiSTAR), University of Naples Federico II, Naples, Italy
• Geology Department, Faculty of Science, Qena University, Qena, Egypt
• Department of Petroleum Geology, Faculty of Petroleum and Mining Sciences, Matrouh University, Marsa Matrouh, Matrouh, Egypt

Short Summary

This study integrated morphometric, geophysical, hydrochemical, and meteorological datasets to assess groundwater potential and recharge dynamics in three Wadi basins along the Red Sea Margin, Northeastern Egypt. The findings prioritize alluvial fan toes and lineament intersections as high-potential sites for managed aquifer recharge and reconnaissance drilling.

Objective

• To characterize the subsurface structure, hydro-stratigraphy, and recharge potential of three Wadi basins (Ramliya, Umm Alda, and Hamad) along the Red Sea Margin, Northeastern Egypt, to prioritize sites for managed aquifer recharge and reconnaissance drilling.

Study Configuration

• Spatial Scale: Three Wadi basins (Wadi Ramliya: 452.6 km², Wadi Umm Alda: 377.4 km², Wadi Hamad: 46.8 km²) along the Red Sea Margin, Northeastern Desert, Egypt. Elevations range from 17.5 m to 1,292 m above sea level. Vertical Electrical Sounding (VES) stations were distributed over an area extending 9,230 m in length and 3,460 m in width. Magnetic survey stations were spaced at intervals of 200–500 m.
• Temporal Scale:
  • CHIRPS satellite rainfall data: 1965–2020.
  • Suez Rain Gauge annual maximum daily rainfall data: 1965–2020.
  • Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) acquisition date: 11 February 2000.

Methodology and Data

• Models used:
  • Archie's Equation (for formation factor, porosity, and water saturation)
  • Analytical Signal (for magnetic data interpretation and depth estimation)
  • Strahler stream ordering
  • Multi-criteria analysis for flood hazard mapping (scoring scheme based on rainfall, drainage density, land-use/land-cover, elevation, and slope)
  • 1-D inversion for Vertical Electrical Sounding (VES) data
• Data sources:
  • High-resolution Digital Elevation Models (DEMs) (Shuttle Radar Topography Mission (SRTM) 1-arc-second (30 m))
  • Multi-azimuth hillshades
  • CHIRPS satellite rainfall dataset
  • Suez rain gauge station data
  • Vertical Electrical Soundings (VES) (28 stations, Schlumberger array, AB/2 ranging from 1.5 m to 500 m)
  • Land magnetic surveys (183 ground stations, Total Magnetic Intensity (TMI), Reduced to the Pole (RTP), and analytic signal filters)
  • Hydrochemical data from JICA-5 borehole (Total Dissolved Solids (TDS), Electrical Conductivity (EC), pH, and ion concentrations)
  • Borehole geological log from JICA-5 (Egyptian Geological Survey)
  • Land-use/land-cover data
  • Road distance data

Main Results

• Topography and Structure: DEM analysis delineated four topographic zones (17.5–1,292 m). Multi-azimuth hillshades revealed dominant NW–SE and NE–SW structural trends that control drainage orientation.
• Morphometrics: Wadi Hamad (46.8 km²) exhibits the highest drainage density (1.79 km·km⁻²), relief ratio (31.3), and bifurcation ratio (3.0), consistent with steep, structurally guided, flash-prone headwaters. Wadi Ramliya (452.6 km²) and Wadi Umm Alda (377.4 km²) primarily act as transit and depositional basins.
• Geoelectrical Imaging: 28 VES resolved a consistent six-layer geoelectric model. A hydraulically significant Middle Miocene calcareous-sandstone aquifer (layer-6) was identified at depths of 77–122 m with resistivities of 12–23 Ω·m.
• Petrophysical Properties: Archie-derived formation factors (4.2–8.2) for the Middle Miocene aquifer imply porosities of 35–49% (mean ≈ 40.6%). Resistivity-based saturation remained low (illustrative Sw = 5.6%).
• Hydrochemistry: Water from the deeper Middle Miocene aquifer (JICA-5 borehole) was classified as slightly brackish (TDS = 2,447 mg·L⁻¹; EC = 3,330 µS·cm⁻¹; pH = 8.2).
• Magnetic Interpretation: Magnetic depth estimates (ranging from approximately 400 m to 1,400 m) and analytic-signal mapping identified shallow structural highs and deeper depocenters, which correlated with depositional fans and VES targets. Dominant N–S, NW–SE, and NE–SW structural elements were delineated.
• Flood Hazard and Recharge Potential: Flood-hazard mapping identified low-slope fan toes and coastal plain cells as high-priority recharge locations, which coincide with favorable geophysical signatures. Integrated data indicate that managed recharge pilots at alluvial fan toes and targeted reconnaissance drilling at lineament intersections are the highest-priority field actions.

Contributions

• Developed an integrated hydrogeophysical and morphometric approach to characterize subsurface structure, hydro-stratigraphy, and recharge potential in arid regions.
• Successfully reduced ambiguities inherent in single-source datasets by combining remote sensing, geoelectrical, magnetic, and hydrochemical data.
• Provided a robust, site-scale framework for prioritizing specific locations for managed aquifer recharge and reconnaissance drilling in the Red Sea Margin.
• Quantified the significant structural control (NW–SE and NE–SW trends) on drainage patterns, aquifer geometry, and potential recharge pathways.
• Characterized the Middle Miocene aquifer's depth, resistivity, porosity, and water quality, offering crucial insights for sustainable groundwater management.

Funding

Open access funding was provided by The Science, Technology & Innovation Funding Authority (STDF) in cooperation with The Egyptian Knowledge Bank (EKB). No specific funding was received for conducting the research presented in this study.

Citation

@article{Hussein2026Hydrogeophysical,
  author = {Hussein, Mahmoud and Araffa, Sultan A.S. and Abbas, Mahmoud Ahmed and Sharkawy, Mahmoud S.},
  title = {Hydrogeophysical characterization and recharge potential of three Wadi basins along the Red Sea Margin, Northeastern Desert, Egypt},
  journal = {Scientific Reports},
  year = {2026},
  doi = {10.1038/s41598-026-37853-9},
  url = {https://doi.org/10.1038/s41598-026-37853-9}
}