Attribution analysis of groundwater storage variations across inland river basins in Northwest China

In this study, to reveal the variability in groundwater storage changes and their driving factors across different inland basins in Northwest China, we applied a comparative framework based on the partitioning of irrigated and non-irrigated regions. Groundwater storage anomaly (GWSA) from 2002 to 2020 was analyzed to characterize its spatiotemporal variations, and the impacts of natural and anthropogenic factors were separated using a water balance approach, with their respective contributions quantitatively assessed. Results show the following ①The overall GWSA decreased at a rate of 0.29 cm/a, exhibiting a spatial pattern of decreasing trends in the north and increasing trends in the south. The rate of decrease in irrigated regions (0.93 cm/a) was approximately four times greater than that in non-irrigated regions, with more pronounced depletion observed in irrigated regions across most basins in both northern and southern Xinjiang. ②The dominant factors of GWSA variations differ significantly among basins, but are generally associated with surface water supply, groundwater withdrawal, and population density. ③In irrigated regions, GWSA variations are mainly associated with groundwater extraction, cropland expansion, and evapotranspiration. Precipitation and surface water recharge exert buffering effects on groundwater depletion in most irrigated regions. However, intensive surface water abstraction has emerged as an important factor in groundwater storage decline in non-irrigated regions, particularly in the Tarim Basin and basins in the Hexi Corridor. These findings provide a scientific basis for the sustainable utilization and management of groundwater resources in arid regions.