High-altitude minor springs in Central Italy tapped for drinking supply: hydrogeological characterization and aquifer potentialities evaluation

In central Apennines’ high altitude villages the water used drinking purpose is guaranteed by springs with seasonal and limited discharge. The small villages located in the south-eastern portion of the Abruzzo region’s mountain area and the northwestern part of Molise region, also known as Alto Sangro area, have reached self-sufficiency because of the presence of many springs located at altitude higher than 1100 m and tapped for drinking purpose; some lack in water availability during summer season were point out, this is due to the impossibility of tap into lower elevations’ springs which are used for the more urbanized coastal areas supply. Despite the strategical position of these springs, the managing companies have preferred different exploitation and distribution policies; currently, water supply from springs or well fields with major potentials is chosen, even if it require more effort for water distribution. In this work, these high altitude aquifers were deepened, defining their characteristics, potentialities and residual capabilities. The geological and tectonical framework is peculiar because the relationships between litholigies are mainly due to faults and low angle thrusts. Consequently, the hydrogeological set-up reflects the geological one, the low angle thrusts put in contact terrigenous lithologies with different permeability (i.e. Gamberale-Pizzoferrato formation), within the so-called Molise units, with the carbonatic succession of the central Apennines and the Sicilidi calcareous-clayey formation (Festa et al., 2014). In this complex hydro-geological framework, groundwater is allowed to emerge as spring: usually, the calcarenites within Molise units, or the Apennines limestone formations work as aquifer, while the clayey complex of the Sicilidi or clay within Molise units, as aquiclude. In some cases, even coarse slope deposits work as aquifer, they were found over the impermeable complex, originated from carbonate deposits located at higher altitude. Analyzing the hydrogeological set-up, these springs were mainly classified as “for permeability limit” (Civita, 1973). These high-altitude springs have an average discharge between 1 l/s and 2 l/s, and the preliminary results about groundwater potentialities were obtained through infiltration coefficient: the found recharge volumes were about 100 Mm3, over a 615 Km2-wide area