Spatiotemporal Groundwater Dynamics and Relative Risk Assessment in the West Liao River Basin, China (2019–2024)

Groundwater is a critical water source in the semi-arid West Liao River Basin (WLRB). Based on daily observations from 117 monitoring wells distributed across the basin during 2019–2024, this study analyzed interannual and seasonal groundwater-level dynamics and identified areas of relative groundwater stress using groundwater level elevation (WLE) and depth to water (DTW). The Mann–Kendall test, Sen’s slope estimator, ordinary kriging, and a composite risk index were applied to quantify temporal trends, map spatial patterns, and classify groundwater risk. Regional WLE showed weak interannual variability but a distinct seasonal cycle, with positive anomalies from January to April and negative anomalies from June to September. At the well scale, 51 wells (43.59%) exhibited significant increases, whereas 36 wells (30.77%) showed significant decreases. Sen’s slope ranged from −2.75 to 0.61 m/year, indicating that the strongest local changes were associated with groundwater-level decline. Spatially, WLE was generally higher in the southwest and lower toward the northeast. Areas with WLE decline were concentrated in the central-western and southern sectors, whereas relative WLE increases occurred in parts of the northern and eastern sectors. The low-, medium-, and high-risk classes included 39, 38, and 39 wells, accounting for 33.62%, 32.76%, and 33.62% of the wells retained for the risk assessment, respectively. High-risk wells clustered in the central-western and southern areas, while low-risk wells dominated the northern and eastern sectors. These results highlight the importance of well-scale monitoring for identifying priority areas of groundwater stress. The proposed framework provides a practical basis for screening priority monitoring areas and supporting spatially differentiated groundwater management in semi-arid basins. However, this study is limited by the relatively short monitoring period (2019–2024) and the lack of quantitative driver attribution; therefore, the findings reflect recent groundwater dynamics rather than long-term secular trends.