Hannan et al. (2025) Regional heterogeneity in groundwater response driven by land-use transitions across Pakistan

Identification

Journal: Journal of Hydrology Regional Studies
Year: 2025
Date: 2025-11-22
Authors: Muhammad Hannan, Chengpeng Lu, Muhammad Waqas, Afed Ullah Khan, Bo Liu
DOI: 10.1016/j.ejrh.2025.102958

Research Groups

College of Hydrology and Water Resources, Hohai University, Nanjing, China
National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, China
Department of Civil Engineering, University of Engineering and Technology Peshawar, Bannu, Pakistan

Short Summary

This study investigated the relationship between land use and land cover (LULC) changes and groundwater storage (GWS) dynamics in Pakistan from 2003 to 2023. It found a national average GWS decline of −5.2 ± 0.7 mm per year, totaling approximately 104 mm over two decades, primarily driven by cropland expansion and reductions in forest, wetland, and open water cover.

Objective

To assess how LULC changes and seasonal variability influence GWS across Pakistan.
To classify and map the spatiotemporal variability of LULC.
To quantify and analyze GWS trends within each LULC category, focusing on seasonal variability using the Seasonal Groundwater Storage Index (SGSI).
To explore the relationship between GWS fluctuations and LULC dynamics.
To discuss the implications for groundwater management, urban development, environmental conservation, and water policy in Pakistan.

Study Configuration

Spatial Scale: National scale, covering Pakistan (796,095 km²).
Temporal Scale: Two decades, from 2003 to 2023.

Methodology and Data

Models used: Global Land Data Assimilation System (GLDAS) with the Catchment Land Surface Model (CLSM), Mann-Kendall (M-K) Test, Sen’s Slope, Seasonal Groundwater Storage Index (SGSI), Continuous Wavelet Transform (CWT) with complex Morlet wavelet.
Data sources: Moderate Resolution Imaging Spectroradiometer (MODIS) MCD12Q1 Version 6.1 for LULC (500 m resolution), GLDAS version 2.2 for GWS estimates (0.25° resolution), GLDAS version 2.1 for precipitation data.

Main Results

Pakistan experienced an average GWS decline of −5.2 ± 0.7 mm yr⁻¹, resulting in a total loss of approximately 104 mm over 20 years.
Central Punjab showed the steepest GWS decline at −8.3 mm yr⁻¹, while Gilgit-Baltistan exhibited a slight increase of +0.4 mm yr⁻¹.
Cropland expanded by 15%, while forest cover decreased by 22%, wetlands by 34%, and open water bodies by 18%. Urban sprawl significantly increased after 2010.
Croplands (Class 12) showed the lowest median GWS decline (−8.2 mm yr⁻¹), and barren lands (Class 16) in Balochistan, which expanded by 12%, showed extreme depletion (−9.1 mm yr⁻¹).
Urban areas (Class 13) were linked to a significant GWS decrease (−7.4 mm yr⁻¹ in densely built areas).
SGSI values were mostly negative after 2013, reaching a low of −1.8 in 2021, indicating reduced monsoon-driven replenishment, despite a peak of +1.9 in the extreme flood year of 2010.
Wavelet analysis revealed prominent inter-annual variability in GWS at 2–7-year scales and longer-term cycles at 10–15-year scales.

Contributions

Provides a comprehensive, nationwide analysis integrating LULC dynamics and seasonal variability with GWS changes in Pakistan, addressing a gap in existing literature.
Utilizes an integrated framework combining long-term MODIS LULC time series, GLDAS GWS data, and the Seasonal Groundwater Storage Index (SGSI) to evaluate standardized groundwater recharge variability.
Employs SGSI and wavelet analysis to differentiate and reveal the combined impacts of land use and seasonal rainfall on groundwater trends.
Offers evidence-based insights with important implications for sustainable groundwater management, urban planning, environmental conservation, and water policy in Pakistan.

Funding

National Key R&D Program of China (2024YFC3211600, 2021YFC3200502)
National Natural Science Foundation of China (41971027, 524032711)

Citation

@article{Hannan2025Regional,
  author = {Hannan, Muhammad and Lu, Chengpeng and Waqas, Muhammad and Khan, Afed Ullah and Liu, Bo},
  title = {Regional heterogeneity in groundwater response driven by land-use transitions across Pakistan},
  journal = {Journal of Hydrology Regional Studies},
  year = {2025},
  doi = {10.1016/j.ejrh.2025.102958},
  url = {https://doi.org/10.1016/j.ejrh.2025.102958}
}

Original Source: https://doi.org/10.1016/j.ejrh.2025.102958