Effects of management measures on groundwater over-exploitation in the Huang-Huai-Hai Plain, China

Groundwater over-exploitation remains a major challenge in the Huang-Huai-Hai (HHH) Plain of China. This study develops an integrated panel-based framework to assess the adjusted associations and relative importance of management measures for shallow groundwater over-exploitation volume (SGOV) and deep groundwater over-exploitation volume (DGOV) during 2014–2021. Two-way fixed-effects-adjusted Pearson correlation (TWFE-APC) was used to characterize contemporaneous and one-period lagged associations after accounting for province fixed effects, year fixed effects, precipitation, and local surface-water exploitation, and two-way fixed-effects partial ridge regression (TWFE-PRR) was used to evaluate joint relative importance. Panel cross-validation, province-block bootstrap analysis, and sensitivity analyses were used to evaluate robustness and uncertainty. External water transfer volume (EWTV) showed the highest relative importance for both SGOV and DGOV. River and lake ecological water supplement volume ranked second for SGOV, whereas water price reform area and efficient water-saving irrigation area followed EWTV for DGOV. The one-period lagged analysis retained the contemporaneous association directions for all six management measures, with EWTV remaining the strongest negative association. Bootstrap analysis supported EWTV’s prominence, while showing greater variability in the exact relative-importance shares and rankings, particularly for SGOV. Overall, water-source substitution emerged as the most prominent management-related pathway, while other measures showed more context-dependent associations.