Zhang et al. (2025) From Depletion to Recovery: Tracking Water Storage Changes in the Semiarid Region of Inner Mongolia, China

Identification

• Journal: Remote Sensing
• Year: 2025
• Date: 2025-11-07
• Authors: Donghua Zhang, Junhuan Peng, Fengwei Wang, Tengfei Feng, Yanan Tian, Ruizhong Gao, Long Ma
• DOI: 10.3390/rs17223668

Research Groups

• School of Land Science and Technology, China University of Geosciences Beijing, Beijing, China
• College of Water Resources and Civil Engineering, Inner Mongolia Agricultural University, Hohhot, China
• College of Surveying and Geo-informatics, Tongji University, Shanghai, China
• School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha, China

Short Summary

This study evaluated spatiotemporal variations in terrestrial water storage (TWS) and groundwater storage (GWS) in semiarid Inner Mongolia from April 2002 to January 2025, revealing a long-term TWS and GWS depletion that notably reversed after 2022 due to policy interventions and precipitation changes, with significant regional differences in driving factors.

Objective

• To evaluate the spatiotemporal variations in terrestrial water storage (TWS) and groundwater storage (GWS) in the semiarid region of Inner Mongolia from April 2002 to January 2025, and to investigate the potential causes of these changes, including the impact of policy interventions.

Study Configuration

• Spatial Scale: Inner Mongolia Autonomous Region, China (approximately 1.18 million square kilometers), encompassing twelve cities.
• Temporal Scale: April 2002 to January 2025 (22 years and 10 months).

Methodology and Data

• Models used: GLDAS hydrological models (Noah 2.1, Catchment Land Surface Model (CLSM) V2.1, Variable Infiltration Capacity (VIC) V2.1).
• Data sources:
  • Satellite gravimetry: GRACE (April 2002–June 2017) and GRACE-FO (June 2018–January 2025) RL06 mascon solutions from CSR, JPL, and GSFC.
  • Hydrological models: GLDAS products for soil moisture storage (SMS), snow water storage (SNWS), and canopy water storage (CWS).
  • Meteorological data: Monthly mean precipitation, evaporation, and runoff data from GLDAS CLSM products.
  • Observation data: Yearly water resources (precipitation, surface water, groundwater) from the Water Resources Bulletin of the Inner Mongolia Autonomous Region (2002–2024).
  • Method: GWS derived by deducting SMS, SNWS, and CWS components from GRACE/GRACE-FO TWS (GWS = TWS − SMS − SNWS − CWS). Ensemble averages of multiple mascon solutions and GLDAS models were used to enhance reliability.

Main Results

• Inner Mongolia experienced an overall terrestrial water storage (TWS) loss of −1.69 ± 0.17 millimeters per year from April 2002 to January 2025.
• This TWS decline was primarily driven by significant groundwater storage (GWS) depletion at a rate of −4.90 ± 0.12 millimeters per year, which offset a slight increase in surface water and other components (SMS + SNWS + CWS) of +3.21 ± 0.19 millimeters per year.
• GWS showed a long-term decline of −5.49 ± 0.17 millimeters per year from October 2007 to April 2022, but notably reversed to an increase of +17.80 ± 0.21 millimeters per year after May 2022.
• Significant regional differences exist: central/southern regions (e.g., Ordos, Baotou, Hohhot) experienced severe water loss (e.g., Ordos GWS: −10.20 ± 0.19 millimeters per year), mainly due to human activities (coal mining, agricultural irrigation).
• Northeastern regions (e.g., Hulun Buir) showed TWS increases (+5.09 millimeters per year), primarily influenced by abundant rainfall, although some short-term net water loss was observed due to climate factors (evapotranspiration and runoff outpacing precipitation).
• The post-2022 groundwater recovery is attributed to a combination of increased precipitation and effective policy interventions, such as strict groundwater extraction controls, ecological water diversion projects, and agricultural water pricing reforms, leading to improved water use efficiency (regional efficiency increased from 64.73% to 72.10% between 2004 and 2023).

Contributions

• Provides a long-term (April 2002–January 2025) and detailed spatiotemporal analysis of TWS and GWS changes in Inner Mongolia, including city-level trends.
• Quantifies the unprecedented reversal of groundwater depletion after 2022, attributing it to a combination of policy interventions and precipitation changes, offering a positive case study for water management.
• Differentiates the primary driving factors (human activities versus climate variability) for water storage changes across different sub-regions of Inner Mongolia.
• Highlights the effectiveness of satellite gravimetry combined with hydrological models for monitoring regional water resource dynamics and informs targeted water redistribution strategies and policy recommendations.

Funding

• Technological Achievements of Inner Mongolia Autonomous Region in China (2022YFDZ0050)
• Natural Science Foundation of China (42374017)
• Natural Science Foundation of Inner Mongolia Autonomous Region (2025SHZR1229)

Citation

@article{Zhang2025From,
  author = {Zhang, Donghua and Peng, Junhuan and Wang, Fengwei and Feng, Tengfei and Tian, Yanan and Gao, Ruizhong and Ma, Long},
  title = {From Depletion to Recovery: Tracking Water Storage Changes in the Semiarid Region of Inner Mongolia, China},
  journal = {Remote Sensing},
  year = {2025},
  doi = {10.3390/rs17223668},
  url = {https://doi.org/10.3390/rs17223668}
}

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