Forecasting the resilience of Bibitarkhoun karst spring, southwest Iran, to the future climate change

Even though the “resilience” term has been widely employed in ecology and somewhat in surface water hydrology, vis-à-vis groundwater, it has been hitherto scarcely utilized. In this study, firstly, the climatic variables of Lali region, southwest Iran, and the discharge rates of a substantial karst spring, i.e. Bibitarkhoun, were obtained in the base (1961–1990) and future (2021–2050) time periods under two Representative Concentration Pathways (RCPs), i.e. RCP4.5 and RCP8.5, utilizing NASA Earth Exchange Global Daily Downscaled Projections data set and artificial neural networks, respectively. Secondly, the spring’s dynamic storages were quantified by depicting its loss curves over the years of the base and future time periods. Thirdly, the Groundwater Resilience Index (GRI) was computed based on the Standardized Precipitation Index approach, using the spring’s discharge rates (GRI1) and dynamic storages (GRI2). The spring’s loss curve corresponds to no-precipitation period, and it was taken into account as the disturbance event to assess the spring’s resilience. Results demonstrated that if the GRI values less than − 1.5, i.e. very and extremely dry years, were taken into account as the disturbance events, the satisfactory condition would be achieved immediately in the next year. Therefore, a promising resilience is expected under climate change. The spring’s loss curves of the observation data indicated it takes approximately three and 5 years to exceed the threshold of 60 and 80% reduction in the spring’s discharge rates, respectively.