Characterizing the recharge of fractured aquifers: a case study in a flysch rock-mass of the northern Apennines (Italy)

12 springs from the northern Apennines of Italy were studied by means of a comprehensive hydrogeological investigation to unravel recharge processes taking place in a highly fractured slab of flysch rock hosting the corresponding aquifers. Several campaigns were carried out during the period 2005\u20132008 to gather springs\u2019 discharge together with electrical conductivity and temperature data. Water samples were collected and allowed the determination of the major ions (Ca2+, Mg2+, Na+ , K+, SO42 12, HCO3 12, Cl 12 ) and the isotopic content (\u3b418O). Additionally, groundwater discharge from 3 selected springs was measured continuously using pressure-transducers. Over the same period, reference \u3b418O values for rainfall and snow-melt water were collected monthly by a rain-gauge. Results highlighted an aquifer-like behavior of this slab of flysch rock. The springs are characterized by a Ca\u2013HCO3 hydro-facies and an increase of groundwater mineralization has been noticed moving toward the base of the slab; the mean discharges are between 0.3 and 0.7 l\ub7s 121 and suffered a marked variability during the year; the total maximum yield is about 155,000 m3 while the total discharge volume is around 320,000 m3\ub7y 121. By processing the \u3b418O isotope values from springs (mean annual values ranged from 129.67 and 1210.42\u2030) and by combining them with rainfalls datasets, results show that the main aliquot of recharge occurs in the winter\u2014spring months and it is principally related to the solid precipitations (snow-melt)