Quantifying resilience for storm drainage management in karst environments with shallow water table

ABSTRACT Storm drainage systems (SDSs) in karstic aquifers traditionally exhibit high drainage efficiency. However, this assumption may be questionable in shallow water table settings, where rapid groundwater rise (karst flash floods) can occur during extreme hydrometeorological events (EHEs). This research addressed aspects of ecological resilience, including (a) a definition of the drainage efficiency thresholds for SDSs, (b) an analysis of the temporal behaviour of the water table depth before, during, and after EHEs, and its relationship to the thresholds, (c) an improved understanding of the implications of the SDSs' response to EHEs. Finally, (d) an estimation of how long EHEs cause SDSs to decrease their efficiency and fail, and (e) provide technical elements to develop SDS management strategies in similar karstic aquifers. Results show that traditional SDSs may experience reduced drainage efficiency for 24 ± 5 days and remain vulnerable to failure for up to 156 ± 20 days after EHEs and during sustained elevated piezometric levels. These findings demonstrate that conventional engineering approaches for SDS design are inadequate under this hydrogeological context. By explicitly quantifying recovery times and operational thresholds, this work introduces a novel and transferable methodology for evaluating SDSs' resilience in karst aquifers with shallow water tables.