Study on dynamic change characteristics of shallow groundwater in arid and semi-arid areas: A case study in the Minqin Oasis, China

Groundwater serves as a critical water resource in arid and semi-arid regions. Analyzing long-term dynamic characteristics of groundwater provides valuable insights for guiding rational development, utilization, and ecological restoration with greater precision. In this study, we focused on Minqin Oasis, a representative arid and semi-arid region in China. Utilizing groundwater depth data collected from 4065 civilian wells during winter and summer of 2019, we simulated groundwater levels using the ordinary kriging interpolation method to delineate spatial distribution patterns. Based on continuous groundwater monitoring data from 12 observation wells spanning 2004–2019, this study analyzed long-term trends in groundwater level variations. Nine indicators related to discharge and recharge processes were selected and examined using principal component analysis to identify key factors influencing groundwater dynamics. The results reveal significant seasonal fluctuations in groundwater levels during 2019, with notably higher variations in winter and summer. Agricultural water use was found to exert a substantial impact on groundwater levels in the study area. Although the declining trend observed since 2004 has been gradually mitigated, and most monitoring sites have exhibited varying degrees of recovery since 2013—with a maximum rise rate of 0.397 m/year—groundwater levels at approximately three-quarters of the observation wells remained below those recorded in 2004 as of 2019. Furthermore, a continued declining trend persists at a few individual sites. These findings underscore the need for enhanced measures to protect and restore groundwater levels in the region.