Wolkeba et al. (2026) Water scarcity indicator based on GRACE derived total water storage for fast water scarcity monitoring

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-03-01
• Authors: Fitsume T. Wolkeba, Mesfin Mekonnen, Kate A. Brauman
• DOI: 10.1016/j.jhydrol.2026.135280

Research Groups

• Department of Civil, Construction, and Environmental Engineering, University of Alabama, Tuscaloosa, USA
• Global Water Security Center, Alabama Water Institute, University of Alabama, Tuscaloosa, USA
• Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, USA

Short Summary

This study introduces a novel water scarcity indicator derived from GRACE total water storage anomaly, offering a robust and efficient alternative to traditional Global Hydrological Model (GHM)-based assessments. The new indicator demonstrates strong alignment with established blue water scarcity metrics and provides comparable estimates of populations and land areas under scarcity.

Objective

• To develop and validate a novel water scarcity indicator based on remote sensing data (GRACE-derived total water storage anomaly) that provides a robust, efficient, and comprehensive alternative to traditional Global Hydrological Model (GHM)-based assessments.

Study Configuration

• Spatial Scale: Global, assessed at grid and basin scales.
• Temporal Scale: Designed for timely monitoring, leveraging GRACE data which typically spans years to decades.

Methodology and Data

• Models used: Novel water scarcity indicator developed based on GRACE total water storage anomaly; compared against seven established blue water scarcity indicators and Global Hydrological Models (GHMs).
• Data sources: Remote sensing data, specifically total water storage anomaly from the Gravity Recovery and Climate Experiment (GRACE).

Main Results

• The proposed GRACE-based indicator shows strong alignment with seven established blue water scarcity indicators at both grid and basin scales.
• It demonstrates no statistically significant difference in estimating population under water scarcity, with a Mean Absolute Relative Error (MARE) of 1.4% at grid scale and 2.3% at basin scale, compared to a blue water scarcity indicator allocating 80% of natural flow for environmental requirements.
• For land areas under water scarcity, the indicator shows no statistically significant difference, with a grid MARE of 1.9% and an F1 score of 0.66, and agreement on 53% of basins, compared to the same blue water scarcity indicator.
• The approach holistically integrates all water storage compartments, including soil moisture, into the total water availability calculation, offering a more comprehensive view of hydrological resources.

Contributions

• Introduces a novel, remote sensing-based water scarcity indicator utilizing GRACE-derived total water storage anomaly.
• Provides a robust, efficient, and less data-intensive alternative to traditional Global Hydrological Model (GHM)-based water scarcity assessments.
• Offers a more comprehensive understanding of water availability by integrating all water storage compartments, including soil moisture (green water), which is often overlooked in traditional blue water assessments.
• Enables more efficient, accessible, and timely global water scarcity monitoring.

Funding

• Not specified in the provided text.

Citation

@article{Wolkeba2026Water,
  author = {Wolkeba, Fitsume T. and Mekonnen, Mesfin and Brauman, Kate A.},
  title = {Water scarcity indicator based on GRACE derived total water storage for fast water scarcity monitoring},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.135280},
  url = {https://doi.org/10.1016/j.jhydrol.2026.135280}
}