Abstract: Pont-du-Gard: Roman Aqueduct Engineering
Lecturer: Patrick Hunt
The 1st century CE Roman aqueduct bridge at Pont-du-Gard is one of the most fascinating engineering achievements in history along with its 50 km (31 mile) aqueduct from its source at Uzès (Ucetia) to the castellum divisorium terminus at Nimes (Nemausus). Created entirely of local limestone without mortar or metal clamps, the aqueduct bridge is triple tiered at 48.8 meters high (160 ft) and is slightly bowed for wind and water resistance with flood water-splitting devices at the Gardon river level, having far more open space than stone for avoiding wind shear. Because the aqueduct bridge is entirely constructed of local stone in ashlar blocks mostly pre-numbered and sized from the quarries, it is already in equilibrium with the environment and the arches of its triple arcades are superbly designed for stability, generally growing stronger with time. The aqueduct itself is constructed of stone and the interior to a certain level is covered with aquatic cement. The gradient of water flow never exceeds 2% to avoid flooding the castellum terminus in Nimes (56 ft or 17 m total differential between the source to the terminus), and the ceramic pipes’ water volume can be adjusted or closed at the castellum. The volume of water per day could be 200,000 m3 (44 million imperial gallons). The technology needed to construct and maintain the Pont-du-Gard will also be shown, along with other briefly-compared Roman aqueducts. Amply illustrated from lecturer’s photos.
Short bibliography on lecture topic:
S. E. Cleary. “Nimes Romaine et l’eau”, Journal of Roman Studies 100 (2010) 37-8
G. Hauck. “The Roman Aqueduct at Nimes”, Scientific American 260 March 1989, 98-100
Trevor Hodge. Roman Aqueducts and Water Supply. Duckworth, 2nd ed. 2002, 87-94 ff.
Patrick Hunt. Alpine Archaeology 2007 (chapter on Roman roads and engineering).