Gier: Durèze + Bozançon

Roman aqueducts: Lyon - Gier aqueduct (France)
For the photo's, see below
For the complete website

Lyon-Gier aqueduct - LUGDUNUM

The Gier was the youngest, longest and highest of the four aqueducts of Lugdunum and had been built in Opus Reticulatum in its whole line. In order to cross the many valleys in its 86 km course, four siphons and 25 bridges ware built. An overview:

Valley / River Constructions Siphon
Durèze Detour plus siphon Header tank plus venter bridge
Bozançon Few bridges, also over side branches -
Mornantet Bridge -
Garon Siphon Header tank 'La Gerle' plus venter bridge
Yzeron Plat de l'Air-arcade, siphon Header tank plus venter bridge Beaunant
Trion Siphon abutment of a header tank Fort Saint-Irénée

Over 50% of the aqueduct was subterranean, with 9 (perhaps 11) tunnels of different length. The deepest was built under the village Mornant just after the river-crossing with the Mornantet. During the construction of the tunnel of Saint-Martin-la-Plaine a miscalculation was made as can be seen on the photographs below.

Because of the total length of the aqueduct, the distance between and the diversity of the manholes could be studied in detail. Out of more than the estimated 1000 manholes, some 85 are known. Where the distance between two adjacent manholes could be measured, the result was between 76 and 78 m, whereas Vitruvius and Plinius indicated 240 Roman feet or 71 m. Jean Claude Litaudon hypothesizes that there were two kinds of manholes in the Gier aqueduct which alternated: the broader ones (3 Roman feet, 92 * 92 cm) with lowered bottom and the smaller ones (2,5 * 2,5 Roman feet, 77 * 77 cm) without. The first ones - a little bit broader than the aqueduct channel - served also as cleaning basins)*.

The Gier was the only aqueduct which also could serve the upper parts of Lugdunum on the Fourvière hill. Although its starting point was on 400 m above sea level, because of its constant and modest gradient the Gier delivered its water on 300 m above sea level, thus 20 - 40 m higher than the other three aqueducts.

W.D. Schram
For the pictures, see below.

)* J.-A. Hamm and J.-C. Litaudon: L'Aqueduc romain du Gier ou du Pilat (2004)

Lyon-Gier aqueduct - LUGDUNUM

Item Info
Length 86 km
Cross-section 0,55 m x 1,30 m
Volume 15.000 m3/day
Fall 0,11 %
Period 50 - 125 AD
Features
  • 4 siphons
  • 80 known manholes



Recommended literature : M. Jean Burdy: Préinventaire des monuments et richesses artistiques IV Gier (1996)
Recommended website : Archeo Lyon
How to visit : See M. Jean Burdy: Guide des Aqueducs Romains de Lyon (1999) and the Recommended literature
HOME More literature on more aqueducts Last modified: March 25, 2005 - Wilke D. Schram (wilke@uu.nl)



Génilac, Header tank

Génical, Header tank

Génilac, Header tank

Génilac, Header tank

Chagnon, Pierre de Chagnon

Chagnon, Pierre de Chagnon

Pierre de Chagnon

Chagnon, Cave de Curé

Chagnon, Cave de Curé

Chagnon, Cave de Curé

Durèze valley, venter bridge

Durèze valley, venter bridge

Saint-Martin-la-Plaine, Fontane tunnel

Saint-Martin-la-Plaine, Fontane tunnel

Saint-Joseph-le-Rieu, manhole

Saint-Joseph-le-Rieu, carved stone

Saint-Didier-sous-Riverie, bridge

Bridge over the Petit Bozanšon

Saint-Didier-sous-Riverie, bridge

Saint Joseph / Saint-Didier

Saint Joseph / Saint-Didier

Saint-Maurice-sur-Dargoire, manhole

Saint-Maurice-sur-Dargoire, manhole

Saint-Maurice-sur-Dargoire, tunnel

Saint-Maurice-sur-Dargoire, bridge

Saint-Maurice-sur-Dargoire, bridge

Saint-Maurice, the 'Pont des Granges' I

Saint-Maurice, the 'Pont des Granges' II

Saint-Maurice, the 'Pont des Granges'

Saint-Maurice, the 'Pont des Granges'

Saint-Maurice, the 'Pont des Granges'

Mornant, Pont de la Condamine

Mornant, Pont de la Condamine

Mornant, Pont de la Condamine