Ben-Salem et al. (2026) The role of secondary data in estimating groundwater levels in the Iberian Peninsula

Identification

• Journal: Groundwater for Sustainable Development
• Year: 2026
• Date: 2026-02-12
• Authors: Nahed Ben-Salem, Amir Rouhani, Nadım K. Copty, Ioanna Anyfanti, J. Jaime Gómez‐Hernández, George P. Karatzas, Michael Rode, Seifeddine Jomaa
• DOI: 10.1016/j.gsd.2026.101594

Research Groups

• Department of Aquatic Ecosystem Analysis and Management, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany
• Institute of Environmental Sciences, Bo˘gaziçi University, Istanbul, Türkiye
• School of Mineral Resources Engineering, Technical University of Crete (TUC), Greece
• Institute of Water and Environmental Engineering, Universitat Politecnica de Valencia, Valencia, Spain
• School of Chemical and Environmental Engineering, Technical University of Crete (TUC), Greece
• Institute for Environmental Science and Geography, University of Potsdam, Potsdam, Germany

Short Summary

This study maps long-term average groundwater levels across the Iberian Peninsula by exploring the value of incorporating various secondary data with cokriging to overcome the scarcity of direct measurements, finding that hydrogeological context significantly improves the reliability of these maps.

Objective

• To assess the spatial variability of groundwater levels for the entire Iberian Peninsula by exploring the value of incorporating different secondary data with cokriging, addressing the challenge of limited high-density direct head measurements.

Study Configuration

• Spatial Scale: Entire Iberian Peninsula
• Temporal Scale: Multi-decadal analysis, using more than 60 years of data.

Methodology and Data

• Models used: Kriging, cokriging (geostatistical methods)
• Data sources:
  • Groundwater level measurements from 3822 observation wells.
  • Digital Elevation Model (DEM).
  • Precipitation data.
  • Hydrogeological information.

Main Results

• Long-term average groundwater levels were successfully mapped for the Iberian Peninsula.
• The value of various secondary data (DEM, precipitation, groundwater level) in estimating groundwater levels was examined.
• Incorporating hydrogeological context significantly increased the reliability of groundwater head maps.
• Annual precipitation showed a weak relation to groundwater level patterns.

Contributions

• Provides a methodology for mapping regional-scale groundwater levels in data-scarce regions by effectively integrating diverse secondary data with geostatistical methods.
• Quantifies the value of different secondary data types, particularly highlighting the importance of hydrogeological context, for improving groundwater level estimations.
• Offers a multi-decadal analysis of groundwater levels for the Iberian Peninsula, a region with significant hydroclimatic variability and water demand.

Funding

• Funding information is not available in the provided paper text.

Citation

@article{BenSalem2026role,
  author = {Ben-Salem, Nahed and Rouhani, Amir and Copty, Nadım K. and Anyfanti, Ioanna and Gómez‐Hernández, J. Jaime and Karatzas, George P. and Rode, Michael and Jomaa, Seifeddine},
  title = {The role of secondary data in estimating groundwater levels in the Iberian Peninsula},
  journal = {Groundwater for Sustainable Development},
  year = {2026},
  doi = {10.1016/j.gsd.2026.101594},
  url = {https://doi.org/10.1016/j.gsd.2026.101594}
}