Tracer tests history in the Alburni Massif (Southern Italy)

The Alburni Massif (Campania, southern Italy) is among the most important Italian karst areas, due to high number of caves (about 300), with several karst systems reaching depth of 500 m, and development of some kilometers. This remarkable karst is mainly related to three geological factors: presence of highly karstifiable and (in average) low-fractured Cretaceous and Tertiary limestones; peculiar morphological and structural conformation, with four main faults bounding the massif, thus forming a wide highplain with a variety of infiltration sites; presence on the highplain of blind valleys and small catchments on flysch deposits, which surface hydrology feeds the many swallets at the contact with the limestone rocks. The Alburni Massif represents an important hydrogeological structure, with a potential of about 10 mc/sec. Three basal spring systems are the main outcomes (Castelcivita, Tanagro and Pertosa) while other minor systems are located at higher elevation, as the Auso spring. The Castelcivita and Pertosa caves, located on the opposite foothills (respectively, SW and NE) of the Alburni Massifs, are of particular importance also from the touristic standpoint and the local economy, since Castelcivita became a show cave in 1930, followed two years later by Pertosa. Since 1950 many cavers have explored the Alburni Massif, due to the high potential of overall karstification, estimated in about 1300 m, and to the presence on the southern slope of the massif of the spectacular Auso spring. In this paper we summarize the t racer tests carried out in the Alburni Massif, with the aim to update the available hydrogeological data, with particular regard to the most recent explorations and tests, carried out during the last 5 years, which brought significant and new data to the overall knowledge of this remarkable karst area of southern Italy.