Pont d'Aël

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Coordinates: 45 ° 40 ′ 36 ″  N , 7 ° 13 ′ 20 ″  E

Pont d'Aël
Pont d'Aël
Pont d'Aël
Today's bridge path runs through the ancient water channel.
use Aqueduct to Augusta Praetoria
Crossing of Grand Eyvia
place District of Pont d'Aël in the municipality of Aymavilles in the Cogne Valley ( Italy )
construction Arch bridge with vaulted vaults
overall length 60.46 m
width 2.26 m
Number of openings 1
Clear width 14.24 m
height 66 m
completion 3 v. Chr.
location
Pont d'Aël (Aosta Valley)
Pont d'Aël

The Pont d'Aël is a Roman aqueduct bridge in the district of the same name in the municipality of Aymavilles in the Aosta Valley in Italy . It was born in 3 BC. Near Augusta Praetoria , today's Aosta , for the irrigation and supply of an ore wash for the newly founded colony . The bridge, located in a side valley 66 m above the valley floor, carried a technically mature aqueduct, a total of 6 km long. In addition to its unusual location, the originally presumably three-story construction has other special features such as an inspection walk under the water pipe and its expressly private financing. A hiking trail now runs in the former water canal.

Exploration and function

The bridge crosses the Grand Eyvia torrent near Pont d'Aël at the entrance to the Cognetal , a side valley 8 km west of Aosta. A first description came from Pingone in 1550, which also included a sketch. Baron de Malzen in 1826 and Aubert in 1860 contributed further illustrations, which already showed the building in its present form. Barocelli added celebrities' measurements from 1864 in 1930 after excavations at the eastern beginning of the bridge.

A complete measurement and documentation was carried out for the first time in 1996 by Mathias Döring. It was proven that the bridge was not a transport route for iron ore , as previously assumed , but belonged to an irrigation line for agricultural areas of the growing colony of Augusta Praetoria and supplied an ore wash for the iron ore extracted in Cogne with water. A drinking water supply for Augusta Praetoria is ruled out, because the city supplied itself from the nearby Buthier . Nevertheless, in addition to its main economic function, the water was also used to meet the local rural drinking water demand.

Irrigation pipe

Half gallery of the aqueduct along the steep slopes of the Cognetal above the bridge

One of the goals of the 6 km long pipeline was an approx. 200  hectare fruit land area in the west of Aosta, which, located 50 to 150 m above the main river Dora Baltea , could only be accessed with the help of a downhill pipeline from the side valley. On the way the water was diverted for the ore washing , which was presumably near the village of Aymavilles . The technical difficulties involved in laying the route along the steep rock faces of the Cognetal were solved by the Roman engineers by laying the pipeline route as a gravity pipeline. The water of the Grand Eyvia, branched off 2.9 km above the Pont d'Aël, was led down the steep slopes of the Cogne Valley in open channels with an average gradient of 6.6 per thousand; Tunnels or qanats were out of the question due to the very hard rock and the required covering of 60 to 120 m. The 1.20 m wide pipeline was cut into the rock slope as a half gallery so that a parapet made of natural rock up to 3 m high remained standing on the valley side. The advantage of this method was that, unlike a tunnel, the driving work could begin at any number of places thanks to the visual contact, which meant a considerable reduction in construction time. In Roman hydraulic engineering, such half-galleries can only rarely be found in particularly impassable terrain, e.g. B. at the water pipe of Side in Turkey .

In the flatter areas, it was decided to have a two to four meter wide terrace through which the pipe ran as a bricked rectangular channel with a plate cover. In total, the line to Pondel crosses 2.25 km of slopes and 0.65 km of rocky sections. The further course of the line below the bridge could not be investigated because of the buildings and agricultural use; the end point is likely to be in the aforementioned irrigation zone near the present-day town of Aymavilles.

Bridge construction

Inspection walk under the water pipe

The 60.46 m long and 2.26 m wide bridge stands at the only possible crossing point over the 4 km long and up to 150 m deep canyon of the Grand Eyvia. Its only arch spans the gorge, which is only 12 m wide but 66 m deep with a span of 14.24 m. The bridge vault consists of a single-rib wedge arch. The once presumably three-story bridge leads to a 50.35 m long corridor on the lower floor, which in ancient times was used to check the tightness of the water pipe above. On both sides of this 3.88 m high inspection corridor there are still two rows of small windows, the lower ones of which illuminated the floor and the upper ones the ceiling so that the bridge keeper could quickly identify any water that might have damaged the masonry in the event of frost . Döring was able to prove beyond doubt the existence of the ancient aqueduct, at the level of which today's hiking trail runs, based on the altitude and course of the remains of the wall and a tunnel to the west of the bridge. Its height was 1.90 m with a width of 1 m. At that time there was possibly an open footpath on the third floor, which gave the building a total height of 22.15 m.

Building inscription

Building inscription
Reconstruction of the building inscription

A large inscription on the north side of the bridge gives detailed information about the builder. Accordingly it was in the year 3 BC. BC by Gaius Avillius Caimus from Padua , one of the tenants of nearby mines, financed from his own resources, which was particularly emphasized by the central arrangement of the word PRIVATVM .

IMP CAESARE AVGVSTO XIII COS DESIG
C AVILLIVS CF CAIMVS PATAVINVS
PRIVATEVM

Completely:

Imperatore Caesare Augusto XIII consule designato
Gaius Avillius Gaii filius Caimus Patavinus
privatum

Translation:

"At the time when the ruler Caesar Augustus was appointed consul for the 13th time,
(has) Gaius Avillius Caimus from Padua, the son of Gaius, (this one built)
from private funds "

Individual evidence

  1. ^ A b Mathias Döring (1998), p. 127
  2. ^ All information: Mathias Döring (1998), p. 131
  3. ^ A b c Mathias Döring (1998), p. 131
  4. ^ A b Mathias Döring (1998), p. 128
  5. ^ All information: Mathias Döring (1998), p. 132f.
  6. ^ Mathias Döring (1998), 128f.
  7. ↑ All information: Mathias Döring (1998), p. 130
  8. ↑ All information: Mathias Döring (1998), p. 131f.
  9. ^ Mathias Döring (1998), p. 132
  10. ↑ CIL 5, 6899 ; see. Mathias Döring (1998), p. 134

See also

literature

  • Mathias Döring: The Roman aqueduct from Pondel (Aostatal) , in: Antike Welt , Vol. 29, No. 2 (1998), pp. 127-134
  • Mathias Döring: The Roman aqueduct from Pondel in Val d'Aosta / Italy. Inventory of the building from the year 3 BC Chr. , In: Communications of the Institute for Hydraulic Engineering and Water Management, Technical University Darmstadt , Vol. 101 (1997)

Web links

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