Discovery of groundwater storage changes and zoning feature variations over the past two decades in the Mongolian Plateau for SDG 6.6

Groundwater is a critical resource for supporting Sustainable Development Goals (SDGs) in arid and semi-arid regions, such as the Mongolian Plateau (MP), which accounts for over 82 % of total water usage in Mongolia; however, its spatiotemporal dynamics remain underexplored. In this study, aiming to enhance the connection between the Groundwater Storage (GWS) and local SDG implementation, we established an integrated analytical framework encompassing groundwater change detection, driving force analysis, and groundwater sustainability assessment. This framework quantifies groundwater storage changes across the MP from April 2002 to December 2023. Results reveal an overall groundwater change rate of −2.96 mm/yr in the MP, which increases in the west and north and decreases in the east, center, and south. The Gobi area has shown increase trends in GWS. Attribution analysis reveals that areas with increasing GWS are more influenced by climatic conditions such as higher precipitation and lower evapotranspiration, while regions with significantly decreasing GWS are associated with insufficient natural recharge and stronger human activity intensity. By contrast, winter precipitation recharge played a crucial role in slowing down the decrease in groundwater storage. In the five major basins of the MP, the dominant factors leading to groundwater depletion varied and were driven by various social factors, such as population, livestock, agriculture, and mining. A dual-index classification combining precipitation minus evapotranspiration (P−ET) and GWS trends provides a convenient, interpretable and objective approach to assessing groundwater sustainability, offering strong correspondence with the Reliability–Resilience–Vulnerability (RRV) framework. This combined strategy not only captures groundwater trends but also enhances interpretability by linking local sustainability levels to both environmental and anthropogenic drivers, underscoring the need for targeted management to support SDG 6.6. The findings of the present study provide an accurate assessment framework and valuable scientific evidence for groundwater resource management in arid and semi-arid regions.