Drivers of Groundwater Storage Dynamics in China’s Ordos Mining Region: Integrating Natural and Anthropogenic Influences

Clarifying the mechanisms through which coal mining affects groundwater storage (GWS) variations is crucial for water resource conservation and sustainable development. The Ordos Mining Region in China, a key energy base in China with significant strategic importance, has undergone intensive coal mining activities that have substantially disrupted regional groundwater circulation. This study integrated data from the Gravity Recovery and Climate Experiment Satellite (GRACE) and Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS) models, combined with weighted downscaling methodology and water balance principles, to reconstruct high-resolution (0.01°) terrestrial water storage (TWS) and GWS changes in the Ordos Mining Region, China from April 2002 to December 2021. The accuracy of GWS variations were validated through pumping test measurements. Subsequently, Geodetector analysis was implemented to quantify the contributions of natural and anthropogenic factors to groundwater storage dynamics. Key findings include: 1) TWS in the study area showed a fluctuating but overall decreasing trend, with a total reduction of 8901.11 mm during study period. The most significant annual decrease occurred in 2021, reaching 1696.77 mm. 2) GWS exhibited an accelerated decline, with an average annual change rate of 44.35 mm/yr, totaling a decrease of 887.05 mm. The lowest annual groundwater storage level was recorded in 2020, reaching 185.69 mm. 3) Precipitation (PRE) contributed the most to GWS variation (q = 0.52), followed by coal mining water consumption (MWS) (q = 0.41). The interaction between PRE and MWS exhibited a nonlinear enhancement effect on GWS changes (0.54). The synergistic effect of natural hydrological factors has a great influence on the change of GWS, but coal mining water consumption will continue to reduce GWS. These findings provide critical references for the management and regulation of groundwater resource in mining regions.