Hydroclimatic Drivers of Groundwater Resilience in Cold Humid Regions

Effective water resource management, particularly in assessing the impacts of climate change on water-abundant regions, is crucial for ensuring long-term sustainability. This study investigates the hydrological response of a cold humid basin with strong groundwater-surface water interactions located in the Great Lakes Basin. We employ a coupled groundwater-surface water model (GSFLOW) to simulate the complex hydrological processes and evaluate the potential buffering capacity of groundwater on surface water systems. Results reveal a strong linear relationship between changes in mean annual precipitation and groundwater recharge (R² = 0.96), with annual precipitation increases over 165 mm required to generate positive changes in recharge. The groundwater system demonstrates significant buffering capacity, particularly in areas with shallow water tables and during hydrological recession periods. Key buffering mechanisms include lagged responses to projected changes in precipitation and recharge relative to the reference period, shifts toward winter recharge, and stable baseflow during dry periods. The aquifer shows greater resilience under the more extreme SSP5 8.5 scenario, suggesting more dynamic surface-groundwater interactions under intense climate conditions. Spatial analysis indicates higher sensitivity to precipitation changes in areas with deeper water tables. The shifts in recharge timing suggest a transition from snow-dominated to rain-dominated winter hydrology, potentially enhancing the system's buffering capacity. These findings provide crucial insights for water resource management in cold humid regions, emphasizing the importance of considering a range of climate scenarios in long-term planning and highlighting the critical role of groundwater in maintaining hydrological resilience under changing climate conditions.