Apulian caves as natural hydrogeological laboratories

Abstract

In Apulia (Southern Italy), there is a huge amount of freshwater resources stored within fractured limestone rocks. Being a karst region, Apulia presents over 2000 caves registered in the Regional Inventory; among these, only in two cases speleologists have physically reached the water table, namely at Inghiottitoio di Masseria Rotolo and at Vora Bosco. Thus, these two caves have become special and natural laboratories in which it is possible to directly study groundwater and its hydrogeological processes. The aim of this research is to assess Apulian groundwater quality and quantity starting from these two caves; for this, some actions have been performed inside the cave systems, and others have to be implemented in the next future. To evaluate groundwater quality, chemical and microbiological analyses have been conducted on groundwater samples, and bio-speleological sampling have been performed too. As regards groundwater quantity, the implementation of the mathematical groundwater flow model is needed. So far, modelers have used Equivalents Porous Media (EPM) approaches that are quite far from the real behavior of karst aquifers. Another purpose of this research is to reduce the existing gap between current models and the natural environment, merging two different approaches: the first implements the laminar flow within fractures and, the second, the turbulent flux inside karst conduits. At this aim, additional geological and hydrogeological data have to be collected. This phase of work will eventually result in getting a better knowledge of the natural dynamics and processes in karst, thus allowing identifying the best actions in order to safeguard and protect the underground freshwater resource.