Tectonic control on groundwater flow in a karst polje of southern Italy

• Main Authors: Isabella Serena Liso, Costantino Masciopinto, Mario Parise
• Other Authors: Liso, ISABELLA SERENA, Masciopinto, Costantino, Parise, Mario
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2021
• Subjects: structural geology; groundwater flow; polje; Ice cap
• Online Access: https://hdl.handle.net/11586/468381; https://doi.org/10.5194/egusphere-egu21-489

In the last decades, climate changes are affecting the freshwater resources quality and quantity around the globe, reducing their availability. On Earth, glaciers and ice cap occupy 68,7%, but they are not easily usable for human purposes; groundwater stands for 30,1%, while surface waters represent the remaining 1,2%. Therefore, groundwater resource is by far the most important natural tank to be preserved. In karst, scientists are still working on developing new methods to understand the true groundwater hydrological behavior, due to subsoil anisotropy in both space and time. This requires a deep knowledge about discontinuity systems in the carbonates, and to improve our comprehension of karst processes, as basic elements for modelling. The possibility to collect data directly from the subsoil, thanks to speleological explorations, is a precious chance for hydrogeology, and in general, for the environmental sciences. In this contribution we take advantage from a variety of speleological data, plus traditional geological surveys, to study groundwater flow in the karst of Apulia. Many karst processes, indeed, affect the Cretaceous limestones belonging to the Apulia carbonate platform, where the deepest cave in the region opens in the Canale di Pirro polje (altitude 300m a.s.l.). This latter is a W-E elongated tectonic-karst valley, representing one of the most significant karst landforms in this sector of Apulia. The cave reaches groundwater at a depth of -260m from the ground surface, whilst additional 60m below the water table have been explored by diving the flooded channels (total depth of the cave 320m). We deal here with characterization of water flow direction into the fractured and karst aquifer, using a combined approach consisting of analysis of: i) primary and secondary discontinuities, ii) shape, size and orientation of karst conduits, and iii) geometry of the intersections between fractures and karst features. The discontinuities have been analyzed with classical geological survey at the surface, ...