Roman 'Well-cisterns', Navigational Routes, and Landscape Modifications in the Venice Lagoon and Northeastern Adriatic

Underwater investigations in the lagoon of Venice have revealed a partially preserved structure interpreted as a Roman 'well-cistern'. It is indeed very similar to another, better-preserved building excavated in the same area. The analysis of the mortar, the evaluation of the depth of the structure base in relation to relative sea level, and the absence of foundation poles in the underlying soft lagoon mud support such interpretation. A comparison with other poorly-studied Roman buildings of the same type located along the North Adriatic littoral suggests that they were probably used to supply ships with fresh water. In the Middle Ages, similar structures were used in the islands of the lagoon for sustenance of its residents and became a characteristic of the small squares (campi) of Venice.