The map of ancient underground aqueducts in Italy: updating of the project, and future perspectives

The Project “The Map of Ancient Underground Aqueducts in Italy” was started in 2003 by the Italian Speleological Society, namely through the work of the Commission on Artificial Cavities. The idea of the project was originated by the huge richness that the Italian territory presents in terms of artificial cavities, in particular as regards hydraulic works (category A in the classification of artificial caves, according to the “typological tree” of the same Commission, that recently has been adopted also at the international level by the International Union of Speleology, UIS). Due to the long history of the country, and to the remarkable Roman domination that extended for centuries over wide portions of Europe and part of Asia, Italy presents on its territory a huge amount of hydraulic works, also with lengths greater than some tens of kilometres, that represent a valuable documentation of the skill and engineering techniques of the ancient communities. Because of the mostly underground development of these hydraulic works, they have often been preserved intact for millennia. Main aim of the Project was to organically collect all the material about underground aqueducts in Italy, through both direct caving explorations and analysis of the available documentation, in order to implement a detailed inventory of ancient underground aqueducts, aimed at contributing to safeguard these unique works of historical and hydraulic engineering importance. A dedicated digital datasheet, consisting of three sections, was therefore created, and used for systematically collect the relevant data and information for each single aqueduct. Even though two time and space requirements were established for inclusion of an aqueduct in the database (the upper time limit is considered to be the 18th century, and the aqueduct must be at least 400 meters long), smaller aqueduct that presented some remarkable peculiarities, or that were particularly interesting for a given territory, were also included. So far, about 140 underground aqueducts, distributed all over the Italian territory, have been identified and studied. In this paper the statistics from the Project are updated and presented, to illustrate the importance in studying this topic, and to highlight the need to develop and carry out further research, from many different approaches: archaeology, hydrogeology, hydraulic engineering, history, etc. At the same time, as already expressed in other congresses, the need to start collecting data and material on underground aqueducts outside of Italy is also discussed, starting from a preliminary bibliography of similar hydraulic works around the world.