VARIABILITY OF GROUNDWATER RESOURCES IN THE CILENTO REGION (SOUTHERN ITALY)

The Cilento is a geographical region of the Campania (southern Italy) whose extended and variegated territory can be considered a particular case of environmental and societal issues concerning the management of groundwater resources. Such problems have become more crucial after the institution of the National Park and the inclusion of a large part of the Cilento region into a total environmental protection zone. Moreover, since 1997, this area has become a UNESCO World Heritage Site and has been incorporated into the network of biosphere reserves of the MAB (Man and Biosphere).
In such a territorial context, balancing the societal demand of drinking water, especially during the summer season when the population grows in the coastal area for touristic influx, is a challenging issue to be managed, especially if considering the typical Mediterranean climate and the conservation of fluvial ecosystems. This problem becomes more critical if taking into account of the long-term effects of climatic variability which leads to an inconstant yearly regime of groundwater flow, from which the most important aqueduct systems are fed.
In particular, the most strategic and relevant groundwater resources of the area are discharges from several springs belonging to karst and, subordinately, terrigenous aquifers. In this contribution to theme water management and use in Mediterranean areas, the impacts of long-term variability of precipitations and groundwater recharge regimes are analysed in the Cilento region. In particular, this research accounts for the effects of the North Atlantic Oscillation (NAO), a well-known continental-scale atmospheric phenomenon [1] consisting in a oscillation, with a complex yearly and decadal periodicity, of the atmospheric masses over the North Atlantic Ocean between the Azores Islands (barometric high) and Iceland (barometric low). The NAO is investigated by comparing measurements of monthly atmospheric pressure between Iceland (barometric low) and Azores (barometric high) and calcultating the NAO Index (NAOI), which is the barometric anomaly, with respect to the standard difference. Many meteorological studies analysed the effects of the NAO on the annual variability of precipitations in the Northern Hemisphere and in the European countries [2].
In this paper, the long-term climatic variability due to the NAO and its influence on groundwater recharge of karst aquifers, which represent the most important groundwater resources of the Cilento region, are analysed by advancing results of recent researches carried out on the recharge of karst aquifers in southern Italy and its decadal variability [3], [4].