The structure of the Pont d'Aël
This is a huge structure in masonry and carved stone blocks, approximately 56 m above the level of the watercourse, of a length that exceeds 50 m.; an inscription placed on the north face allows its dating to the year 3 A.D. and recalls the promoter and owner, Caius Avillius Caimus, Patavinus, a native of Padua.
The structure consisted of a covered passage of approximately 1 m. in length, illuminated by narrow windows on both walls, which were reached by openings with wooden fittings on both sides; the one on the top is a continuation of an external chimney cut in the rock.
An open upper channel, with stone slabs on the bottom and waterproof walls, allowed water to run after its capture from sources located on the left bank of the river; from the western level, it is still possible to see remains of the hydraulic system of which the facility was a part.
The thesis of a connection of the work with the activity of extraction and handling of iron material in the upper and central valley of Cogne, although accepted in the community to be from the Roman era, has not been proven. Based on the available information, it is reasonable to suppose a short-term bridge-aqueduct function in the territory, consisting of the water supply of a fundus, a land property assumed to have existed on the site of the modern-day village. The adjective privatum set in the inscription otherwise defines its legal nature unequivocally.
Later modifications to the conduit and to the body of the structure - with the opening, including a postern gate on the south face of the facility - indicate the functioning of the water capture system even in the post-classic age.
Among the 32 imposing aqueducts of the Roman Empire distributed throughout Europe, Africa and the Middle East, this monumental work is unique of its kind based on the following undeniable elements:
- the type of bridge with the double function of pedestrian passageway and aqueduct placed on two different levels;
- the peculiarity of the pedestrian passage carved out within the brick facing built to support the channel for running water on the upper level;
- the survival of the inscription carved by the builders on three large stone slabs placed immediately above the vault keystone of the most visible upstream front arch and intended for utility flows, an inscription that immortalized the names of the owners Aymus ... Avilius. It establishes the date of inauguration in the 12th year from the establishment of the empire of Caesar Augustus, corresponding in the Christian era to the third year A.D.;
- the legal term PRIVATUM engraved by precedence on the central stone slab over the other two, an indication of private property that distinguishes it from the other 32 aqueducts, which are great public works built to bring water to cities, characterizing the expansion of the Roman empire;
- its daring design was conceived to resolve the difficult, impassible leap over the gorge of the Grand Eyvia, the river of the valley of Cogne made by the glaciers of the Grand Paradis mountain;
- the moderate state of preservation that allows nearly a complete reading of the original state;
- the un-interrupted use over the millennia as a bridge serving the rural community for the pedestrian connection between two slopes;
- the rate of the discharge of the aqueduct established at 975 msl, not exceeded anywhere in the Alps;
- the 3500 meters across the aqueduct from the discharge to the bridge, that in the tracts of Charpinel and of the Eteley leave one astonished before the ingenuity and constructive capacity in overcoming technical difficulties to cross extremely high sheer walls spread along the route.