# Geohydroology of a Reference Mediterranean Catchment (Cilento UNESCO Geopark, Southern Italy)
## 2 Materials and Methods  
### The Study Area  
The Ciciriello study area (LAT 40.1957 LONG 15.5379) is located in the Cilento and Vallo di Diano National Park-UNESCO Global Geopark, southern-east of Campania, Southern Italy. The area of the watershed is about 3 km\({}^{2}\) and it is a dominantly forested area, with a presence of few farms, without relevant human impacts (Figure 1), such as burning fossil fuels or deforestation. Elevation in the watershed ranges from 420 to 812 m asl (Marchese Mount). From a hydro-geomorphological point of view, the Cilento and Vallo di Diano Geopark (Figure 1) consists of carbonate massifts, terrigenous reliefs and alluvial plain aquifers [32]. The conglomerate-arenaceous and sandstone-arenaceous hydrogeological complexes in Figure 1 are distributed over approximately 15% of the territory (1497 km\({}^{2}\)) and form the typical hilly landscapes of the central part of the Cilento Geopark, except for the mountainous massifts of Mount Sacro (1705 m asl), Mount Centaurino (1433 m asl) and Mount Stella (1130 m asl). They are constituted by terrigenous sedimentary formations (sandstone and conglomerates) in turbidite facies (Lower- Mid Miocene) and are generally laying on older alternate beddings of marly-calcareous and/or silicoclastic arenites beds, with interbedded fissile mudrocks (silt shale, clay shale and marls). Previous hydrogeological studies [33] revealed that the effective infiltration in these units was about the 19% of the net annual precipitations (excepting the evapotranspiration). This value has to be expected to be lower for rock-mass that has a prevalent clayy component, such as the basal formations. Figure 1: Hydrogeological map of the UNESCO Cilento Global Geopark (red square indicates the Ciciriello catchment location). In these, the weathering process and the fracturing of the regolith induce to the surficial part of the flysch rock-mass a relatively higher permeability, allowing the formation of a shallow groundwater flow [34]. Such groundwater circulation occurs by means of groundwater bodies that are generally discontinuous and ephemeral and whose spatial and temporal distribution reflect the development of the weathering profile and slope morphology, as well as the occurrence of precipitations. Groundwater flow is mainly oriented downstream or toward small springs located along the slopes. Due to such a hydrogeological framework, water issues are generally attributable to both the diffuse scarcity of groundwater for regional domestic and agricultural uses and to the limited or null relevance of these units to represent aquifers of strategic regional relevance. Small springs fed by this type of groundwater circulation, with discharges that are variable from a few liters per minute, represent significant local groundwater resources, especially for the hilly areas distant from the water feeding by streamflow. An exception from this general hydrogeological behavior is represented by the lithoststratigraphic units of the Cilento Group [35]. In these parts of the sedimentary series, the prevalence of sandstone beds and conglomerates banks and the lateral discontinuity or the lack of interbedded mudstone layers, to the aquifer rock-mass, a relative medium rate of permeability. Therefore, for these units, the effective infiltration is higher, with values of up to 30% of the net precipitations, as was demonstrated by hydrogeological studies carried out on the stream flows data of the western side of the Mount Sacco [33]. In these units, the groundwater circulation is deeper and characterized by an outflow less controlled by the slope morphology and more influenced by the stratigraphic and structural aquitard/aquiclude setting, as well as by the lateral juxtaposition with units that have a lower relative rate of permeability. A large number of springs can be correlated to this type of groundwater circulation [36] and the several local hydro-domestic systems in the area feeding by them.