GRACE-derived groundwater storage anomalies and their lagged responses to climatic and anthropogenic drivers in the West Liaohe River Basin, China

Study region The West Liaohe River Basin (WLRB), northern China, is a semi-arid mountain–plain system linking mountainous recharge zones to a heavily irrigated downstream plain. Study focus Using GRACE/GRACE-FO and climatic, ecological, and water-use data (2002–2024), we assessed groundwater storage anomaly (GWSA) trends, lagged associations with environmental factors, and relative predictor importance using correlation, Bayesian lag analysis, and Random Forest models. New hydrological insights for the region GWSA declined significantly across the WLRB, plain, and mountainous areas at −5.94, −5.96, and −5.91 mm yr⁻¹, respectively (p < 0.001). Depletion intensified after 2011 and persisted after 2018 despite increasing precipitation, indicating that wetter conditions did not reverse groundwater losses. Associations with climatic and ecological variables were concentrated mainly within 1–6 months, with stronger and more spatially coherent soil moisture associations in the plain. The negative soil moisture–GWSA relationship may partly reflect the subtraction of soil moisture from GRACE-derived terrestrial water storage. Precipitation associations were weak, consistent with indirect rather than immediate recharge responses. Random Forest analysis identified irrigated area as the strongest negative predictor in the whole basin and plain, whereas groundwater withdrawal showed the strongest negative association in mountainous areas. These contrasts highlight the need for coordinated, regionally differentiated groundwater management.