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All French heritage classified by regions, departments and cities

  2. Patrimoine
  3. Auvergne-Rhône-Alpes
  4. Loire
  5. 42400 Saint-Chamond

  6. Aqueduct of the Gier section of Langonand

Aqueduct of the Gier section of Langonand à Saint-Chamond dans la Loire

Aqueduct of the Gier section of Langonand

    2 Allée Jean le Rond d'Alembert
    42400 Saint-Chamond
Private property
Museums of France
All canals, aqueducts, locks, gazes classified from France
Photo de Aqueduct of the Gier section of Langonand
Crédit photo : Arnaud Fafournoux - Sous licence Creative Commons

Timeline

Antiquité
Haut Moyen Âge
Moyen Âge central
Bas Moyen Âge
Renaissance
Temps modernes
Révolution/Empire
XIXe siècle
Époque contemporaine
100
200
…
1800
1900
2000
vers 110 ap. J.-C.
Construction under Trajan
1887
Discovery of the Stone of Chagnon
1908
Thesis of Germain de Montauzan
2018
Heritage Lotto Selection
3 mars 2022
Protection section of the Langonand
Aujourd'hui
Aujourd'hui

Heritage classified

The canal sis chemin de la Marquette and the land corresponding to the presumptive zone of archaeological prescription, on Parcel No. 41, in the cadastre section ZA: inscription by order of 28 September 2023

Key figures

Trajan - Roman Emperor (98–117 AD) Regulated during the construction of the aqueduct.
Hadrien - Roman Emperor (117–138 A.D.) Author of a protection edict (Pierre de Chagnon).
Germain de Montauzan - Archaeologist (XX century) Author of the thesis of reference (1908).
Guillaume Marie Delorme - Antiquarian (18th century) First complete line of the aqueduct.
Paul de Gasparin - Engineer (19th century) Cartography and technical calculations (1834).

Origin and history

The Gier Waterway, 86 km long, is one of four ancient aqueducts serving Lugdunum (Lyon). Probably built under Trajan (circa 110 AD), it draws its waters from the river Gier, tributary of the Rhone. Its route, studied from the 16th century by scholars such as Pierre Sala and Guillaume Marie Delorme, combines tunnels, bridges-siphons and covered trenches. The section of the Langonand in Saint-Chamond includes a 200 m water bridge crossing the Janon valley, partially buried in 1998.

The dating of the water pipe was debated: initially attributed to Claude or Auguste, the discovery in 2018 of wooden forms dated 110 A.D. (Trajan rule) allowed to clarify its construction, although a finish under Hadrian remains possible. Some protection points, such as the Pierre de Chagnon (1887), attest to strict regulations to preserve the work, incorporating an Augusean law prohibiting ploughing or planting nearby.

Ranked as a Historical Monument in successive waves (1875, 1912, 1930, 1986), the aqueduct uses various Roman techniques: siphons (Dureze, Yzeron), tunnels (825 m in Mornant), and canal bridges like that of the Air Plat (Chaponost), adorned with reticulatum. The section of the Langonand, protected in 2022, includes five batteries visible from the seven to nine originals, illustrating Roman engineering adapted to the relief.

Modern research, from the work of Germain de Montauzan (1908) to recent excavations, has refined the knowledge of his route and of his 1,000 viewings spaced according to Vitruve's recommendations. Despite the deterioration (movement of a section to Chaponost in 2006), restorations (2010 in Chaponost) and legal protections aim to preserve this exceptional heritage, selected for the Heritage Lotto in 2018.

The Gier's aqueduct symbolizes the climax of Roman hydraulic engineering in Gaul, combining technical innovation (high pressure siphons, waterproof mortar opus signinum) and landscape integration. Its route, from Saint-Chamond to Lyon, crosses 14 communes, with emblematic remains such as the bridge-siphon of Beaunant (123 m of arrow) or the arches of the Air Plat, classified in 1900.

External links

Page Wikipedia
Page Monumentum