Water resource assessment in karst and fractured aquifers of Termini Imerese-Trabia Mts. (Northern central Sicily, Italy).

The carbonatic siliciclastic Mesozoic reliefs of Termini Imerese-Trabia Mts. (Northern central Sicily) were selected in order to investigate groundwater resources, as these fissured to karstic aquifers are used for potable water supply. These reliefs, part of the Sicilian Apennine Chain, consist of a tectonic units (deformed and emplaced during the Miocene-Pleistocene, and collapsed during the Plio-Pleistocene) mostly formed by clayey pelagic limestones (Sicilidi domain) overthrusting Meso-Cenozoic carbonate and silicoclastic rocks (Imerese Basin, Late Triassic-Early Oligocene) and terrigenous covers (Numidian Flysch, Late Oligocene-Early Miocene). The evolution of karstic network and subsurface drainage systems has been favoured by tectonic structures, the Messinian Salinity crisis (latest Miocene) and Quaternary eustatic sea-level changes. Several large-capacity wells drilled in the area, are strategic for water supply of both the city of Palermo (about 800.000 inhabitants) and eastern metropolitan region. Water shortage in some towns has been intensified by the indiscriminate exploitation of several springs most of which have disappeared. These events have produced a progressive groundwater resource reduction and threat of seawater intrusion. Moreover, the occurrence of potential pollution producing industries (Termini Imerese industrial zone) could also compromise freshwater quality. Several hydrothermal superficial manifestations, related to deep carbonate reservoir, occur in this region. The groundwater flow is controlled by the main tectonic fractures and by several karstic forms. The importance of a qualitative and quantitative study of the water resources in some hydrostructures influenced by the potential interaction of several factors is here proposed.