Uncertainties in understanding groundwater flow and spring functioning in karst

In karst environments, typically characterized by peculiar hydrogeological features and high heterogeneity and anisotropy, the connection between the recharge areas and the springs is often not straightforward. Rapid infiltration underground and the resulting network of karst conduits are frequently at the origin of a lack of correspondence among topographic divides and underground watersheds. As a consequence, in many karst areas there is still much work to do to fully understand the groundwater flow, with the only “underground truth” often being provided by cave data. In this chapter, we start from general considerations about the difficulty in comprehending hydrogeology in karst and use them to analyze one of the most important karst areas of southern Italy, the Alburni Massif in Campania. In detail, we present data about the main karst features at the surface (dolines, endorheic basins, etc.), the most important cave systems (reaching maximum depth of about 450 m below the surface), and the main basal springs coming out at the massif borders. Integration of the different sources of data allows us to hypothesize the main directions of groundwater flows, and to perform the first attempts in correlating recharge and discharge data, but such hypotheses then often prove to be wrong by data from cave and diving explorations.