Aqua Alsietina

Roman aqueducts: Rome Aqua Alsietina (Italy) Rome - ROMA Aqua Alsietina
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Augustus constructed the Aqua Alsietina in 2 BC. The Alsietina and Traiani are the only two aqueducts to draw their water from an area other that the Anio watershed to the east and southeast of Rome. The Alsietina took its water directly from the southern side of Lake Alsietinus, at a height above sea level of 207 m, a small crate lake east of Lake Sabatinus. The opening of the tunnel, which was the lake's only emissary, has been found in the hillside 12 metres above the current water level (Aicher, 1995:41).
Unknown course
Aqua Alsietina acc. to J.B. Piranesi
Of the Alseitina's 33 kilometre length, only about 500 metres was above ground. Much of the course is unknown. From the lake it headed due south towards Osteria Nuova. South of here it passed near to the abandoned S. Maria di Galeria, where a branch from Lake Sabatinus joined it. It entered the city to the north side of the (later) Porta Aurelia and after a short stretch of arches dropped underground again to the Trastevere. A short section of its tunnel has been discovered near S. Cosimato (Aicher, 1995:41). Frontinus mistakenly states that the Alsietina is the lowest of the aqueducts.
Frontinus states that he is unclear as to why the Alsietina was built because its waters were unfavourable for drinking. He assumes that its purpose was to furnish Augustus' Naumachia at Trastevere with water, and while that was not in use, all the water was delivered 'extra urbem'. There was no evidence regarding the existence of any piscina, which adds weight to the theory that the Alsietina did not service public needs, but was used for private purposes. There is some evidence from Frontinus, however, that indicates that its waters were also used to irrigate gardens and country villas located along the Alsietina's course, thanks to the generosity of Augustus. Despite its poor quality, the water was used for drinking when the conduits of the Marcia and Virgo, crossing the river to Trastevere, were closed for repairs. This aqueduct supplied only 6,000 m3 of water per day )1. All of this water was consumed outside of the city. One problem with using the Alsietina's water for the Naumachia was its height. The Alsietina entered the city at a much higher level than the Naumachia; dropping the height of the water over such a short course is problematic.

)1 Aicher (1995) differs in his estimate, giving a figure of 16,000 m3 per day.

From E.J. Dembskey: The aqueducts of Ancient Rome" (master thesis 2009)

HOME More literature on more aqueducts Last modified: January, 2010 - Wilke D. Schram (

Alsietina channel


Conduit of the Alsietina

marble plan

A Naumachia

Ancient drawing