A Dynamic Framework for Quantifying Groundwater Resilience to Rainfall Variability: Integrating Engineering and Ecological Resilience Perspectives

Groundwater systems play a vital role in maintaining water supply during periods of climate extremes such as droughts. However, the decreased recharge, coupled with the increased pumping rates, interferes with the natural feedback mechanism of the aquifer system, potentially pushing them beyond their resilience thresholds and causing regime shifts. Understanding and quantifying groundwater resilience is essential for evaluating how these systems maintain stability and adaptability under stress. Historically, resilience has been viewed through two lenses: engineering resilience, which emphasizes the speed of recovery to a single equilibrium, and ecological resilience, which focuses on the system’s ability to absorb disturbances before shifting to a different state. The latter approach acknowledges multiple stable states and the possibility of regime shifts. While both perspectives are essential, no existing framework has integrated them to provide a comprehensive understanding of groundwater resilience. This study presents the Endurance, Recovery, and Resilience (ERR) framework, which combines engineering and ecological resilience definitions to assess the stability and adaptability of groundwater systems. We define resilience as the ability of a system to endure disturbances and return to its original stable state, capturing both recovery and adaptability dynamics. We apply the ERR framework to seasonal groundwater levels and rainfall time series of 19 subbasins in the Ganga Basin. Using Wavelet Transform Decomposition, we isolate rainfall-induced groundwater fluctuations and calculate their magnitude of oscillation as Groundwater Sensitivity to Rainfall (GSR). This GSR time series serves as the state variable for computing the Dynamic Resilience Indicator (DRI), which reflects the groundwater system's states and resilience under different conditions. Our findings reveal that groundwater systems exhibit multiple stable states and adaptive regime shifts in response to rainfall variability. Subbasins with high resilience show better adaptability to rainfall changes, whereas low resilience subbasins display limited response, suggesting a need for more tailored management strategies. The ERR framework provides a robust methodology for assessing groundwater resilience, with broader implications for adaptive management across environmental systems. By integrating both engineering and ecological perspectives, this framework offers valuable insights for understanding and managing groundwater resources amidst the challenges posed by climate variability.