Preliminary notes of the research on the Roman aqueduct of Alba Fucens (AQ) in Italy. The geophysical prospecting in the study of the free-flowing channel and the inverted siphon.

The Latin colony of Alba Fucens was founded by Rome at the end of 4th century BC. In the late-republican age it was supplied by an aqueduct capable of providing water to the city from a distance of 10 km thanks to a channel and an inverted siphon. Mentioned in two inscriptions inherent some restoration works dated to the first half of 1st century AD, there is still little know about the Alba aqueduct’s complete course and function; it is one of the earlier aqueducts with a siphon in Italy. Geophysical surveys were performed in order to understand the development of the siphon venter, from the ruins of Arci toward Alba and, behind there, to the connection point of the free-flowing channel with the header tank. From here the specus starts and the pipeline sticks out and goes down in the valley, which was crossed at the bottom by a wide siphon bridge with arcades. The large structure in polygonal masonry of Arci, an embankment 11.90 m wide and 14 m high over which were mounted the pipes, as in the case of Patara, represents the only trace of the aqueduct venter visible today.