ORCID
- G. Masselink: 0000-0001-6079-7611
- D. C. Conley: 0000-0001-6822-5386
Abstract
This study examines the spatial variability of shallow groundwater on Dhigelaabadhoo Island using electromagnetic induction surveys, groundwater monitoring, and sediment analyses. The research reveals how variations in island morphology—such as differences in elevation, reef flat width, and sediment composition—affect the spatial distribution of groundwater lenses and the overall aquifer dynamics. Saltwater intrusion is especially pronounced in low elevated areas, with narrow reef flat plate and areas where higher hydraulic conductivity—driven by the presence of coarser sediments—is observed, whereas regions characterized by finer sediments, higher elevation, and wider reef flat plates tend to support more symmetric and less saline groundwater lenses. The geophysical investigations reveal that tidal oscillations alter groundwater movement by markedly changing water levels and conductivity, thereby underscoring the critical need to account for temporal dynamics in atoll coastal aquifer systems and the importance of integrating tidal dynamics into the aquifer zone. The findings highlight the significant role of intrinsic morphological and external hydrodynamic factors in shaping groundwater distribution on atoll islands, offering critical insights for sustainable freshwater resource management.
DOI Link
Publication Date
2026-01-01
Publication Title
Journal of Hydrology
Volume
664
ISSN
0022-1694
Acceptance Date
2025-11-03
Deposit Date
2026-03-04
Funding
This research was funded by the EPSRC Research Grant EP/X029506/1 awarded to Gerd Masselink, University of Plymouth and the U.S. Geological Survey’s, United States, Coastal and Marine Hazards and Resources Program. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. We gratefully acknowledge the ARISE team for their invaluable assistance with fieldwork.
Additional Links
Keywords
Atoll islands, Electromagnetic induction, Groundwater, Morphological variability, Tidal dynamics
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Tobon-Velazquez, N., Masselink, G., O’Hare, T., Bates, R., Oberle, F., Storlazzi, C., & Conley, D. (2026) 'Groundwater spatial variability within an atoll island: Assessing shallow aquifer heterogeneity with geophysical and physicochemical measurements', Journal of Hydrology, 664. Available at: 10.1016/j.jhydrol.2025.134560
