Groundwater planning and protection: assessment of environmental indexes in complex aquifer systems. The Solofrana River Valley case study (South Italy)

Heterogeneity of natural systems governs the pathway of pollutant in the environment, mostly in groundwater resources. A large number of hydrogeological researches aim to parameterize and model these processes. Namely, the spatial variability of the hydrogeological properties of rocks may be defined from geologic observations and local measurements. The Solofrana River Valley (South Italy) is a real natural laboratory to improve understanding of the behaviour and transfer of pollutants on large scale. The geological and structural complexity of the territory, due to the tectonic and morphological evolution of the carbonate platform domains, resulting in filling of the structural depressions by the quaternary deposits (volcanic, talus and alluvial sediments), is combined with a widespread agricultural activity and with the incidence of important industrial centres, among which stands out the Solofra’s tanning pole. A multidisciplinary approach was employed to delineate aquifer/aquitard unit and characterize scale-dependent heterogeneity by means of geological, hydrogeological and geochemical techniques. This paper describes firstly the experience carried out in an area characterized by a high anthropic impact. Besides, it reports about relevant geological and hydrogeological aspects of the Solofrana River Valley and presents some interesting aspects related to field operations and characterization of pollutants flow and transport. Existing data, combined with a specific geological survey and a monthly water level monitoring (July 2010; February 2011-October 2012), as well as a groundwater chemical-physical characterization based on a monthly EC, pH and temperature monitoring and on chemistry analyses involving 77 parameters (July 2010 - April-June 2012), provided to assess the groundwater composition indexes and the chief environmental indexes. So the improvement of the hydrostratigraphic architecture and the hydraulic continuity among aquifers, especially pushing up depths, derived from the assessment of equivalent parameters of hydrodynamic properties. With regard to the hydrogeological and impact conditions, the results of multivariate statistical analyses proved the identification of a number of homogeneous zones even in such complex aquifer systems.