Unravelling Groundwater–Precipitation Interactions in Karst Aquifers Under the Dual Pressures of Climate Variability and Human Disturbance

ABSTRACT Karst aquifers exhibit complex groundwater–precipitation interactions shaped by climatic variability, internal structural heterogeneity and human disturbance. However, the mechanism by which climate‐driven recharge signals are transformed by karst flow architecture and simultaneously modulated by anthropogenic pressure across multiple timescales remains unclear. Herein, we investigated the coupled influence of climate variability and human disturbances on groundwater dynamics in a typical heterogeneous, fracture‐dominated karst aquifer in northern China. Three process‐oriented insights emerged: (1) Human disturbance (particularly spring irrigation) had a prominent influence on seasonal groundwater decline and exceeded climatic forcing during critical periods. (2) Groundwater levels (GWLs) exhibited rapid (~10 days), seasonal (~40–80 days) and quasi‐annual (~320 days) variability in response to precipitation (P), reflecting the interaction between fast preferential pathways and slow storage components. (3) Strong spatial heterogeneity was evident; urbanised discharge zones showed markedly reduced recharge transmission owing to surface sealing, whereas permeable recharge areas remained highly responsive to P inputs. Flow partitioning indicated a pronounced dual‐flow structure, with recharge zones exhibiting mixed behaviour and quick flow contributions of 31.2%–36.2%, whereas discharge zones were strongly dominated by slow flow (~87.4%), highlighting the buffering role of aquifer storage in smoothing climatic signals. Overall, these findings advance the process‐based understanding of how karst aquifers filter, store and transmit P signals under coupled climate–human forcing. These insights are transferable to other karst regions and support the diagnosis of the dominant factors controlling groundwater dynamics under global environmental change.