Recharge assessment of the Gran Sasso aquifer (Central Italy): Time-variable infiltration and influence of snow cover extension

Study region: Carbonate karstified aquifers represent one of the most important groundwater reservoirs for both drinking purposes and environmental preservation. Currently, the recharge-discharge equilibrium in these aquifers is at risk of depletion from withdrawal increases and global change effects. Based on these factors, detailed analyses of recharge distribution over the last 20 years (2001-2020), both in terms of rainfall and snow melting contributions, have been carried out for the Gran Sasso regional aquifer (Central Italy). Study focus: Using the same input data, water budgets at different time scales were calculated using the Turc, Thornthwaite and APLIS methods. In addition, simplified future scenarios considering the real risk of climate change effects have been implemented by applying an increase in temperature and a shortage of snow coverage periods. New hydrological insights: The obtained aquifer recharge values are similar and a significant contribution to recharge from snowmelt has also been highlighted. The measured spring discharge values are higher with respect to the calculated recharge, especially in drought periods, underlining the resilience of groundwater resources in the Gran Sasso aquifer; these values are also confirmed by the different responses of spring discharge to recharge variations. A significant decrease in recharge and consequently in baseflow discharge is conceivable for future scenarios, revealing that immediate optimization measures are required to correct groundwater resources management and to avoid potential emergency conditions.