Il patrimonio "cavo". Architetture ipogee e spazio idraulico nella piana di Palermo

The valorisation policies and protection of “visible” architectural heritage are often promoted by the public opinion, that immediately perceives in the artefacts or landscape degradation the risk of an irreparable loss. Conversely, the safeguard of the underground built heritage is ever more difficult to achieve. It is the case of the "hollow architecture" functional to ensuring water provisioning in the Plain one of Palermo, the so-called “horizontal wells”. The most interesting aspect is the complex dense network of canals for the abstraction of groundwater resources. These artefacts date back to the sixteenth century – though an older dating is not to be excluded – and they outline the historical agricultural landscape. Commonly located near the old city of Palermo, different formal and structural features - while all ascribable to the same centuries-old tradition – suggests a contextual investigation on much broader geographic areas. This may help identifying a tradition adopted from other civilizations, in particular Middle Eastern, which developed political, commercial, and cultural relationships in the Western Sicilian area over the centuries. The benefit of these studies here presented is more evident if we consider the scarcity of documentary material and specialised literature. The need of a deeper and well-structured knowledge on the subject is shown by a number of uneducated – and thus detrimental – works of consolidation and conservation. Often these works, either old or recent, have been carried out by different operators in the construction sector without an adequate knowledge. Some case-studies has been examined, allowing to identify a record of damages to which these artefacts are usually subject. The on-going study strengthens the idea that Sicilian culture reprocessed various influences coming from outside the island in the field of hydraulic engineering, while generating original and completely new artworks to recognize, promote, and protect both their technological features and their anthropological expression