Recharge processes of Matese karst massif (southern Italy)

The recharge processes have been evaluated for the Matese massif, a wide karst system of southern Italy, which feeds several major springs. This massif is characterized by wide endorheic areas exploited for hydroelectrical purposes; several hydraulic works have modified the natural recharge processes of the Massif and the regime of karst springs. Recharge on massif is based on the annual means recharge estimation by GIS, using regression of annual mean values of different ground-elevated rain gauges and thermometers. A calibrated daily scale recharge model estimates the amount of effective rainfall that is retained as soil moisture, the amount reaching the water table (recharge s.s.), and the amount of runoff leaving the catchment. All these amounts vary through the hydrological year, as so function of soil moisture deficit and daily rainfall intensity. When soil moisture reaches the field capacity, daily rainfall exceeding 24.3 mm develops runoff; the runoff amount increases during wet year and reduces during dry years, highlighting the important role of the endorheic areas mainly during wet years. The ratio between the total water volume spring outlet and the effective rainfall (effective recharge coefficient) has been estimated for several hydrological years and varies between 0.81 (dry year) and 0.58 (wet year).