Surface landforms and speleological investigation for a better understanding of karst hydrogeological processes: a history of research in southeastern Italy

Abstract

Small-size karst landforms may potentially provide very useful information to fully understand the behaviour of karst systems and their dynamics. In this chapter we demonstrate the need to pay attention to such features. ‘Inghiottitoio della Masseria Rotolo’, located in a remarkable karst area of southern Italy, has in recent years become the most controversial and discussed speleological site in Apulia. Even though it has been known for several decades, recently excavation work has allowed cavers to enter a huge karst system, eventually reaching the water table. The total depth of the cave is now 324 m, making it the deepest in the region. This chapter summarizes the history of discoveries at the site, starting from the description of the polje, also including information about the link between toponymy and karst. The works carried out at the swallet site are then described to emphasize the importance of the often neglected small-size karst features. In fact, when carefully observed and studied, these might be able to shed new light and greatly increase our knowledge about karst. The final part of the chapter deals with the cave system and provides an outline of the ongoing research.

Geomorphological and structural characterization of the ‘Canale di Pirro’ polje, Apulia (Southern Italy)

“…As testified by the story regarding IMR (Liso et al, 2020;Parise & Benedetto, 2018), it is worth to recall the importance of taking into the due account in karst terrain even small surface landforms such as swallow holes. Being their location typically not casual, observation of the dynamics of these features in different situations can provide significant elements for a full comprehension of the functioning of karst systems, and help in defining the most proper management actions in the fragile karst environments.…”

“…At least 15 caves are registered in the regional cadastre of karst caves (http://www.catasto.fspuglia.it/) within the Canale di Pirro, most of them being of very limited size. The remarkable exception is represented by 'Inghiottitoio di Masseria Rotolo' (IMR; inghiottitoio means swallow hole; corresponding to PU_355 in the main map), that is a very interesting a complex karst system (Figure 3), reaching the water table at a depth of −264 m (Liso et al, 2020;Parise & Benedetto, 2018). Following scuba-diving exploration below the water table, the site has become the deepest known cave in Apulia (depth 324 m).…”

An Integrated Geophysical and Unmanned Aerial Systems Surveys for Multi-Sensory, Multi-Scale and Multi-Resolution Cave Detection: The Gravaglione Site (Canale di Pirro Polje, Apulia)

“…Under the surface, many caves open within Canale di Pirro; even though typically of limited size, and often used as stables for livestock, the longest and deepest cave of the region (Grave Rotolo, [40][41][42]) opens at the polje bottom. The karst geomorphological data collected at the Canale di Pirro polje have been summarized in the map shown in Figure 3 and they are described in detail by Pisano and co-authors [31].…”

“…The Canale di Pirro bottom hosts two main swallow holes: Rotolo cave (PU 355) and Gravaglione (PU 354). Another minor swallet, corresponding to Grotticella del Canale di Pirro (PU 1509), was destroyed years ago to create a vineyard on the southern side of the polje, and its precise location has been lost [40]. As typical of poljes in other karst regions of the world [43][44][45][46][47][48][49], the Canale di Pirro polje often presents flooded sectors, becoming temporary lakes after severe storms [46,50], due to the hydraulic functioning of the swallow holes at its bottom.…”

Recent advances in karst research: from theory to fieldwork and applications

“…In this regard, recent work in southern Italy has shown the importance of mapping and taking into consideration even smallsized karst landforms. Parise & Benedetto (2018) describe a small swallet in Apulia (SE Italy), which at the ground surface looks like a simple site of infiltration of water during heavy rainstorms. After several weeks of excavation, with the permission of the landowner, access was found to a remarkable underground system, reaching the deep water table at −260 m depth and going down for several tens of metres underwater, as documented by speleodiving exploration.…”