Attribution analysis of groundwater depth dynamic changes in the water receiving region of the South-to-North water diversion middle route project in China

Study Region: The South-to-North Water Diversion Middle Route Project (SNWD-MRP) waterreceiving region in Henan Province, China. Study Focus: Geostatistical methods and linear regression analysis are employed to investigate the spatiotemporal variation characteristics of unconfined aquifer groundwater from 2005 to 2021, and assess the impact of the SNWD-MRP on groundwater depth (GD) changes in the waterreceiving region of Henan Province. New Hydrological Insights for the Region: GD generally showed a continuous decreasing trend during Phase 1 (2005-2014), and this decreasing trend slowed down in Phase 2 (2015-2021). High-intensity agricultural water consumption was identified as the primary factor inhibiting groundwater recovery, while the SNWD-MRP played a positive role in groundwater recovery during seasons with non-agricultural water consumption. Results from the Geodetector model show that the SNWD-MRP significantly strengthens the spatial correlation between natural factors and GD. However, as the SNWD-MRP's influence on driving factors increases, the corresponding improvement in spatial correlation diminishes, indicating a negative correlation. This study reveals that although the overall groundwater trend continues to decline, the SNWD-MRP has positively contributed to groundwater recovery and influenced the evolution rules of GD.