Analysis of recharge processes in some karst systems, Southern Italy

The recharge processes have been evaluated for some karst massifs of southern Italy. The first step is the evaluation of the annual mean recharge for a long-time period (30 years) by GIS tools, by regression analysis of annual mean values of different ground-elevated rain gauges and thermometers. The estimation takes into account the presence of the wide endorheic areas, or “closed areas”, distinguished from the rest of the catchment, characterized by the open areas. In a first step, the ratio between the output spring discharge and input rainfall has been also estimated (long term recharge coefficients) for both closed and open areas. The second step is the assessment of the daily recharge, splitting the daily rainfall into several amounts (evapotranspiration, soil moisture retention, recharge s.s. and runoff), calibrating the daily simulation on the long-term recharge coefficient found in the first step. These analyses have been carried out for the Cervialto karst massif (southern Italy) where climate and hydrological parameters are available for many years, and the severe drought conditions of the 2016-17 are also outlined; brief comparisons were also carried out between Cervialto massif, considered as a pure climate controlled aquifer and other nearby karst massif as Terminio and Matese, whose recharge processes are conditioned by groundwater abstraction in endorheic areas.