Aqua Alexandrina

The Aqua Alexandrina (Italian: Acquedotto alessandrino) was a Roman aqueduct located in the city of Rome. The 22.4 km long aqueduct carried water from Pantano Borghese to the Baths of Alexander on the Campus Martius. It remained in use from the 3rd to the 8th century AD.

The aqueduct was constructed in AD 226 as the last of the eleven ancient aqueducts of Rome. It was built under the reign of Emperor Alexander Severus to supply his enlargement of the Thermae of Nero which have been renamed after the emperor (Thermae Alexandrinae). The aqueduct was repaired for the first time in the era of Diocletian between the 3rd and 4th century, later between the 5th and 6th century and finally in the 8th century during the reign of Pope Adrian I. The aqueduct was described in the 17th century by Raffaello Fabretti (1680).

The Aqua Alexandrina received its water from the Pantano Borghese swamp near the city of Gabii, now a part of Monte Compatri. The same spring has supplied the Acqua Felice since 1586. The first 6,4 km of the total 22,4 km were tunnelled underground, later run on the surface and 2,4 km was carried on brick arches traversing the valleys of the Roman Campagna. Its last section towards and inside the city remains uncertain (the urban parts are uncovered) but supposedly the aqueduct entered the city at Porta Maggiore and ended on the Campus Martius at the Thermae of Alexander, between the Pantheon and the Piazza Navona. Depending on the season, the aqueduct supplied 120,000 to 320,000 cubic meters of water per day.

The arches of the aqueduct are made of concrete with brick coating. There are four small travertine brackets at the top of each pillar whose function remains unknown.

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