Mon Aug 24, F. Flechtner
• Sorted by Date • Sorted by Last Name of First Author •
Udoka, Ubong Paulinus and Pavelka, Karel, 2026. Estimating Long–Term Groundwater Storage Change in the Chad Basin, Nigeria, Using GRACE/GRACE–FO and GLDAS Terrestrial Water Storage Anomalies. ISPRS – International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 49B3:859–864, doi:10.5194/isprs-archives-XLIX-B3-2026-859-2026.
• from the NASA Astrophysics Data System • by the DOI System •
@ARTICLE{2026ISPAr49B3..859U,
author = {{Udoka}, Ubong Paulinus and {Pavelka}, Karel},
title = "{Estimating Long-Term Groundwater Storage Change in the Chad Basin, Nigeria, Using GRACE/GRACE-FO and GLDAS Terrestrial Water Storage Anomalies}",
journal = {ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences},
year = 2026,
month = jul,
volume = {49B3},
pages = {859-864},
abstract = "{The Chad Basin is the main source of fresh water to over 30 million
people in the semi-arid Sahel region, and long-term evaluation
of groundwater resources is crucial for sustainable abstraction
of fresh water, water security for the region, and humanitarian
resilience. Using the GRACE/GRACE-FO satellite gravimetry and
GLDAS land surface modelling, this study was used to assess the
hydrological variations in one of the least data-rich and most
water-drafted transboundary basins in the world. Results show an
important hydrogeological paradox. The overall trend in the
basin-scale water mass, as revealed by Total Water Storage
Anomaly (TWSA), is a strong increase of +5.91 mm/year
(R{\texttwosuperior} = 0.70). However, recoverable water
components are diminishing, with surface water, soil moisture,
and Groundwater Storage Anomaly (GWSA) decreasing at
{\ensuremath{-}}1.04, {\ensuremath{-}}1.02, and 0.02 mm/year,
respectively. This means that a higher absolute amount of water
stored does not necessarily lead to an increase in groundwater
recharge, probably because of high evaporation, extraction
pressures, and hydrogeological conditions. Spatial analysis also
reveals areas of critical groundwater depletion along the
western boundary of the basin, especially across the
northeastern part of Nigeria, where groundwater extraction is
high. Rainfall trends are weak (+1.65 mm/year) and not
significantly correlated with groundwater storage (r =
{\ensuremath{-}}0.176), indicating that recharge efficiency to
the deep aquifers is poor. The overall conclusion is that the
anthropogenic pressures on water scarcity are growing, and the
use of evidence-based transboundary governance, regulation of
groundwater abstraction, and targeted Managed Aquifer Recharge
strategies is needed.}",
doi = {10.5194/isprs-archives-XLIX-B3-2026-859-2026},
adsurl = {https://ui.adsabs.harvard.edu/abs/2026ISPAr49B3..859U},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
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