Built in 3BC for irrigation purposes, The Pont d'Ael is a Roman aqueduct. It is located in a village of the same name in Aosta valley in northern Italy. It was built to supply water to the newly founded Augusta Praetoria, now known as Aosta. The water was directed through a sophisticated system from a neighboring valley which is 66m above the floor of Aosta valley. The aqueduct is 6km long. The bridge was originally thought to be a three-storey structure. It shows the unique features such as a control corridor and explicit private funding in addition to its unusual position.
Next to the entrance to the Cogne Valley, which is around 8 km west of Aosta, The bridge traverses the Grand Eyvia river at Pont d'Ael. In the year 1550, along with a sketch, Pingone recorded the first description of the bridge. Illustrations were further contributed by Baron de Malzen and Aubert further in 1826 and 1860 respectively which already showed the construction in present form. After excavations on the eastern edge of the bridge in 1930, Barocelli added the measurements from 1864. Mathias Doring first carried out a complete survey and documentation in 1996. He discovered that the bridge is used as an irrigation pipeline for agricultural land and a washery for the iron ore in Cogne and belonged to the growing colony of Augusta Praetoria Salassorum. Because the town itself got its water supplied from the nearby river Buthier, the idea of a bridge being a water supply for Augusta Praetoria was ruled out.
Over the 4 km long and upto 150 m deep canyon of the Grand Eyvia, the 60.46 m long an 2.26 m wide bridge is the only possible crossing point. It's only arch spans the gorge with a span of 14.24 m which is only 12 m wide but 66 m deep. The arch of the bridge consists only a single stone. A 50.35 m long corridor, on the lower floor of the bridge, verifies the density of the overlaying water pipe in antiquity. The lower floor of the bridge was once probably three stories high. There are two rows of small windows on both sides of this 3.88 meter high control corridor, from which the lower floor an the upper ceiling are illuminated. It is illuminated so that the bridge keeper could identify the leakage as the leakage could have damaged the stonework with frost.
On the bridge the following has been inscribed:
IMP CAESARE AVGVSTO XIII COS DESIG
C AVILLIVS C F CAIMVS PATAVINVS
Which is completed as:
Imperatore Caesare Augusto XIII consule designato
Gaius Avillius Gaii filius Caimus Patavinus
"When emperor Caesare Augustus was consul for the 13th time"
"Caius Avillius Caimus from Padua, son of Caius, [built this bridge]"
"using private funds"