Aqua Traiana

The Aqua Traiana (later rebuilt and named the Acqua Paola) was a 1st-century Roman aqueduct built by Emperor Trajan and inaugurated on 24 June 109 AD. It channelled water from sources around Lake Bracciano, 40 kilometers (25 mi) north-west of Rome, to Rome in ancient Roman times but had fallen into disuse by the 17th century. It fed a number of water mills on the Janiculum, including a sophisticated mill complex revealed by excavations in the 1990s under the present American Academy in Rome. Some of the Janiculum mills were famously put out of action by the Ostrogoths when they cut the aqueduct in 537 during the first siege of Rome. Belisarius restored the supply of grain by using mills floating in the Tiber. The complex of mills bears parallels with a similar complex at Barbegal in southern Gaul.

Original Sources of the Aqueduct

Both the ancient Aqua Traiana and the modern Acqua Paola were fed by a collection of aquifer sources in the hills around the volcanic basin of Lake Bracciano. The Italian archaeologist Alberto Cassio in his Route of the Ancient Waters, and his successor Rodolfo Lanciani in 1881 in his Commentary on Frontinus list the sources in the following groups, running clockwise around the lake from Bracciano: