Synergistic Effects of Mine Dewatering and Climate Change on a Vulnerable Chalk Aquifer (Chełm Region, Poland)

This study assesses the long-term impact of mine dewatering on groundwater resources in the fractured–porous Upper Cretaceous chalk aquifer of the Chełm region, SE Poland. Using precipitation records (1994–2024) and groundwater levels from 50 sites (2009–2025), temporal trends were tested with Mann–Kendall, Sen’s slope, Kendall’s tau, and regression, while spatial patterns were evaluated with Local Moran’s I and Getis–Ord Gi*. Results show no significant changes in total annual precipitation but declining snow days (–1 to –1.5 days/year) and rising temperatures (0.02–0.05 °C/year), indicating reduced snowmelt recharge. In contrast, groundwater levels declined consistently, with a median Sen’s slope of –0.14 m/year and drawdowns > 22 m near the chalk mine. Spatial clustering confirmed coherent zones of decline in mining and watershed areas. These findings indicate that climate variability alone cannot explain the observed drawdown; mine dewatering is the dominant driver, reinforced by reduced winter recharge. The results highlight the urgent need for integrated monitoring and adaptive management to protect groundwater-dependent ecosystems. Sustainable water management in mining-affected aquifers must address both anthropogenic pressures and climate-induced reductions in recharge.