Anthropogenic coal mining reducing groundwater storage in the Yellow River Basin.

Anthropogenic coal mining and water consumption affect groundwater storage (GWS) and impose substantial pressure on water resources. However, the responses and mechanisms of GWS to these activities and climate change are not well understood. In this study, the impacts of anthropogenic coal mining, water consumption, vegetation restoration and climate change on GWS in the Yellow River Basin (YRB) of China were quantitatively assessed, based on the Gravity Recovery and Climate Experiment (GRACE) satellite data, land surface model simulations, Random Forest (RF) model, normalized vegetation index data, the statistical information in yearbooks and bulletins, and in situ observations. The results revealed a significant decline at a rate of -7.52 mm⋅year in GWS from 2003 to 2020, with the most pronounced decreasing trends in the middle and lower reaches of the YRB. Seventy-five percent of the regions with a gain in GWS showed an increasing trend in the net water flux (precipitation minus evapotranspiration). The RF model results show that water consumption by coal mining is the main factor influencing changes in GWS in the eastern and northern coal mining areas of the basin, with importance scores of 50-53. Significant vegetation restoration increased groundwater drought in the YRB, especially in the growing season. This study provides valuable scientific insights for formulating water resource management policies in the YRB.