Parsimonious recharge/discharge modeling in carbonate fractured aquifers: The groundwater flow in the Gran Sasso aquifer (Central Italy)

In the carbonate fractured aquifer of the Gran Sasso (Central Italy), numerical simulations have been applied to validate a conceptual model of the recharge/discharge cycle at regional scale. To identify the effective aquifer features that mostly affect the spring discharges, simple parsimonious models, based on few key parameters whose effective values are well-constrained by previous hydrological/geological studies, are used. Input data are represented by infiltration, calculated considering rainfall, snowmelt and runoff in endorheic basins, and effective permeability distribution, estimated by geological, tectonic and hydrogeological settings of the aquifer. Discharges of tapped springs and tunnel drainages for the 1999–2009 period have been simulated, after estimating the recharge area of each monitored spring by the hydrogeological setting and checking them by mean isotope elevation values. Discharge monitoring has been compared with the simulations, obtaining a good agreement both at seasonal and yearly time basis. The simulations will also be useful for previewing discharge in drought period and evaluating protection zones of tapped springs in the territory of a National Park.