Groundwater recharge distribution due to snow cover in shortage conditions (2019–22) on the Gran Sasso carbonate aquifer (Central Italy)

Aquifer recharge by the snowpack is relevant to be assessed to evaluate groundwater availability in mountainous karst regions. The recharge due to snowpack in the Gran Sasso aquifer has previously been estimated through an empirical approach using elevation gradients. To validate and quantify the coverage and persistence of the snowpack over time through an objective method, satellite images have been analysed. The Campo Imperatore plain, the endorheic basin acting as a preferential recharge area of the aquifer, plays an important role, both for the snow cover and also for the infiltration and recharge of springs. The identification of recharge areas has been validated by the stable isotope approach with the assessment of computed isotope recharge elevation based on the values and oscillations of the delta O-18 isotope recorded at the springs. The main findings confirm the high infiltration rate of Campo Imperatore plain and its direct influence on snow contribution to aquifer recharge. The extension of snow coverage out of this plain has a minor influence to recharge, highlighting that the main drivers for infiltration rate are fractured networks and karstic forms more than snow coverage on carbonate outcrops.