ABSTRACT
Roman engineers contributed to shaping coastal and deltaic landscapes into territories of water. These territories of water were made of intricate natural and man-made waterways connecting different coastal environments together. Navigable canals were the most prominent features connecting coastal settlements and ports through a wide range of geomorphological units (e.g. sea, river mouths, channels, lagoons, harbours) to create larger navigable networks with higher connectivity. However, Roman engineers had to deal with natural processes that constrained their coastal planning (e.g. floods, storms, sedimentation, erosion). Diverted waters modified source-to-sink continuum at the interface between continental and marine waters. Consequently, some canals needed strong maintenance and did not work as planned, while some others became additional deltaic branches in activity until today.
The first part of this chapter presents evidence that can be collected by geophysicists, geomorphologists and archaeologists to identify and characterise a Roman navigable canal. Based on the example of Ostia and Portus in the Tiber delta, the chapter presents and clarifies the different research objectives sought by geoarchaeologists (water and sediment management) and archaeologists (navigability) regarding canal networks dug during the Roman period.
