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The Fontaine d'Eure, at {{convert|76|m|ft}} above sea level, is only {{convert|17|m|ft}} higher than the delivery tank in Nîmes, but this provided a sufficient gradient to sustain a steady flow of water to the 50,000 inhabitants of ''Nemausus''. The aqueduct's average gradient is only 1 in 3,000, and is as little as 1 in 20,000 in some locations. It is estimated that it supplied the city with around {{convert|200,000,000|L|impgal}} of water a day.<ref name="Langmead">{{cite book|title=Encyclopedia of architectural and engineering feats|editor1=Langmead, Donald|editor2=Garnaut, Christine|page=254}}</ref> The spring still exists and is the site of a small modern pumping station, providing water that is pure but high in dissolved ] leached out of the surrounding ]. The carbonates caused significant problems for the maintenance of the aqueduct, as they precipitated out of the water ''en route''. This led to the flow of the aqueduct progressively becoming reduced by deposited carbonates.<ref name="Bromwich=112">Bromwich, p. 112</ref> The Fontaine d'Eure, at {{convert|76|m|ft}} above sea level, is only {{convert|17|m|ft}} higher than the delivery tank in Nîmes, but this provided a sufficient gradient to sustain a steady flow of water to the 50,000 inhabitants of ''Nemausus''. The aqueduct's average gradient is only 1 in 3,000, and is as little as 1 in 20,000 in some locations. It is estimated that it supplied the city with around {{convert|200,000,000|L|impgal}} of water a day.<ref name="Langmead">{{cite book|title=Encyclopedia of architectural and engineering feats|editor1=Langmead, Donald|editor2=Garnaut, Christine|page=254}}</ref> The spring still exists and is the site of a small modern pumping station, providing water that is pure but high in dissolved ] leached out of the surrounding ]. The carbonates caused significant problems for the maintenance of the aqueduct, as they precipitated out of the water ''en route''. This led to the flow of the aqueduct progressively becoming reduced by deposited carbonates.<ref name="Bromwich=112">Bromwich, p. 112</ref>


Like most Roman aqueducts, most of it was built underground. It was constructed by digging a trench in which a stone channel was built, enclosed by an arched stone roof and covered with earth. Some sections of the channel are tunnelled through solid rock. In all, {{convert|35|km|mi}} of the aqueduct was constructed below the ground.<ref name="Bromwich-111">Bromwich, p. 111</ref> The remainder had to be carried on the surface, either on a wall or on arched bridges. Some substantial remains of the above-ground works can still be seen today, such as the so-called "Pont Rue" that stretches for hundreds of metres around Vers.<ref name="Bromwich-112-113">Bromwich, p. 112-113</ref> However, the Pont du Gard is by far the best preserved section of the entire aqueduct. Like most Roman aqueducts, most of it was built underground. It was constructed by digging a trench in which a stone channel was built, enclosed by an arched stone roof and covered with earth. Some sections of the channel are tunnelled through solid rock. In all, {{convert|35|km|mi}} of the aqueduct was constructed below the ground.<ref name="Bromwich-111">Bromwich, p. 111</ref> The remainder had to be carried on the surface, either on a wall or on arched bridges. Some substantial remains of the above-ground works can still be seen today, such as the so-called "Pont Rue" that stretches for hundreds of metres around Vers and still stands up to {{convert|7.5|m|ft}} high.<ref name="Bromwich-112-113">Bromwich, p. 112-113</ref> However, the Pont du Gard is by far the best preserved section of the entire aqueduct.


===The Pont du Gard=== ===The Pont du Gard===

Revision as of 07:57, 3 September 2010

Pont du Gard (Roman Aqueduct)
UNESCO World Heritage Site
CriteriaCultural: i, iii, iv
Reference344
Inscription1985 (9th Session)

The Pont du Gard is a notable ancient Roman aqueduct bridge that crosses the Gard River in southern France. It is part of a 50 kilometres (31 mi) long aqueduct that runs between Uzès and Nîmes in the South of France. It is located in Vers-Pont-du-Gard near Remoulins, in the Gard département. The aqueduct was constructed by the Romans in the first century AD and was added to UNESCO's list of World Heritage Sites in 1985. It is the highest of all Roman aqueduct bridges and is the best preserved after the Aqueduct of Segovia. Today it is one of France's most popular tourist attractions.

Description

The aqueduct

Aqueduct of the Pont du Gard between Uzès and Nemausus (Nîmes)

The aqueduct of the Pont du Gard originally carried water from a source at the Fontaine d'Eure near Uzès to a delivery tank in Nemausus, Roman Nîmes. Although the straight-line distance between the two is only about 20 km, the aqueduct takes a winding route measuring around 50 km to avoid the Garrigue hills above Nîmes. The Garrigues are the southernmost foothills of the Massif Central. They are difficult to cross, as they are covered in dense vegetation and indented by deep valleys.

The Fontaine d'Eure, at 76 metres (249 ft) above sea level, is only 17 metres (56 ft) higher than the delivery tank in Nîmes, but this provided a sufficient gradient to sustain a steady flow of water to the 50,000 inhabitants of Nemausus. The aqueduct's average gradient is only 1 in 3,000, and is as little as 1 in 20,000 in some locations. It is estimated that it supplied the city with around 200,000,000 litres (44,000,000 imp gal) of water a day. The spring still exists and is the site of a small modern pumping station, providing water that is pure but high in dissolved calcium carbonate leached out of the surrounding limestone. The carbonates caused significant problems for the maintenance of the aqueduct, as they precipitated out of the water en route. This led to the flow of the aqueduct progressively becoming reduced by deposited carbonates.

Like most Roman aqueducts, most of it was built underground. It was constructed by digging a trench in which a stone channel was built, enclosed by an arched stone roof and covered with earth. Some sections of the channel are tunnelled through solid rock. In all, 35 kilometres (22 mi) of the aqueduct was constructed below the ground. The remainder had to be carried on the surface, either on a wall or on arched bridges. Some substantial remains of the above-ground works can still be seen today, such as the so-called "Pont Rue" that stretches for hundreds of metres around Vers and still stands up to 7.5 metres (25 ft) high. However, the Pont du Gard is by far the best preserved section of the entire aqueduct.

The Pont du Gard

Built on three levels, the Pont is 49 metres (161 ft) high above the river at low water and 274 metres (899 ft) long. Its width varies from 9 metres (30 ft) at the bottom to 3 metres (9.8 ft) at the top. The three levels of arches are recessed, with the main piers in line one above another. The span of the arches varies slightly, each being constructed independently to provide flexibility to protect against subsidence. Each level has a differing number of arches:

Level Number of arches Length of level Thickness of piers Height of arches
Lower 6 142 metres (466 ft) 6 metres (20 ft) 22 metres (72 ft)
Middle 11 242 metres (794 ft) 4 metres (13 ft) 20 metres (66 ft)
Upper 35 (originally 47) 275 metres (902 ft) 3 metres (9.8 ft) 7 metres (23 ft)

The first level of the Pont du Gard carries a roadway that was added in the 18th century. The water conduit or specus, which is about 1.8 metres (5.9 ft) high and 1.2 metres (3.9 ft) wide, is carried at the top of the third level. The upper levels of the bridge are slightly curved in the upstream directions, a fact long attributed to the engineers wanting to strengthen it against the flow of water, like a dam wall. However, a microtopographic survey carried out in 1989 showed that the bend is caused by the daily expansion and contraction of stones under the heat of the sun, by about 5 millimetres. Over the centuries, this process has produced the deformation witnessed now.

The Pont du Gard was constructed entirely without the use of mortar or clamps. It contains an estimated 16,000 tons of stone – some of the individual blocks weigh up to 6 tons – that were precisely cut to fit perfectly together by friction alone, eliminating the need for mortar. The masonry was lifted into place by block and tackle with a massive human-powered treadmill providing the power for the winch. A complex scaffold was erected to support the aqueduct as it was being built. The face of the aqueduct still bears the mark of its construction, in the form of protruding scaffolding supports and ridges on the piers which supported the semicircular wooden frames on which the arches were constructed. Various inscriptions are found across the surface, containing instructions used in construction. For example, "FRS II" (frons sinistra II, Latin for "left face 2"), phallic symbols (intended to ward off bad luck), and graffiti left by builders throughout the ages.

Although the exterior of the Pont du Gard is rough and relatively unfinished, the builders took care to ensure that the interior of the water conduit was as smooth as possible so that the flow of water would not be obstructed. The walls of the conduit were constructed from dressed masonry and the floor from concrete. Both were covered with a stucco incorporating minute shards of pottery and tile. It was painted with olive oil and covered with maltha, a mixture of slaked lime, pork grease and the viscous juice of unripe figs. This produced a surface that was both smooth and durable.

History

It has long been thought that the Pont du Gard was built by Augustus' son-in-law and aide, Marcus Vipsanius Agrippa, around the year 19 BC. Newer excavations, however, suggest the construction may have taken place between 40 and 60 A.D; consequently, opinion is now somewhat divided on the matter. Designed to carry the water across the small Gardon river valley, it was part of a nearly 50 km (31 mi) aqueduct that brought water from the Fontaines d'Eure springs near Uzès to the Castellum in the Roman city of Nemausus (Nîmes).The full aqueduct had a gradient of 25 cm/km (1/4000), descending only 12 m vertically in its entire length and delivering 35,000 cubic meters of water daily.


It is believed to have taken about fifteen years to build, employing between 800 and 1,000 workers.

Post Roman

From the fourth century onwards, its maintenance was neglected, and deposits filled up to two thirds of the conduit space. By the ninth century, it became unusable, and the people of the area started using its stones for their own purposes. However, the majority of the Pont du Gard remains impressively intact.

From the Middle Ages to the 18th century, the aqueduct was used as a conventional bridge to facilitate foot traffic across the river, like its much smaller sister, the Pont de Bornègre. The pillars of the second level were reduced in width to make more room for the traffic, but this jeopardized the stability of the structure. In 1702 the pillars were restored to their original width in order to safeguard the aqueduct. In 1743, a new bridge was built by a French engineer Henri Pitot next to the arches of the lower level, so that the road traffic could cross on a purpose-built bridge. The aqueduct was restored in the 18th century, by which time it had become a major tourist site, and was restored again in the reign of Napoleon III in the mid-19th century.

The outstanding quality of the bridge's masonry led to it becoming an obligatory stop for French journeymen masons on their traditional tour around the country (see Compagnons du Tour de France), many of whom have left their names on the stonework. Markings left by the original builders can also be seen, indicating the positions in which the dressed stones were to be placed: for instance, FRS II (standing for frons sinistra II, or "front left 2"). This is a tradition that has been partly continued by modern visitors, often looking to make their own markings.

In May 1940 a French pilot, Séraphin Civera, flew his plane through one of the arches.

The Pont du Gard was added to UNESCO's list of World Heritage Sites in 1985. The description on the list states: "The hydraulic engineers and ... architects who conceived this bridge created a technical as well as artistic masterpiece."

In 1998 the Pont du Gard was hit by major flooding which caused widespread damage in the area. The road leading up to it and the neighboring facilities were badly damaged, although the aqueduct itself was not seriously harmed.

The French government sponsored a major redevelopment project in conjunction with local sources, UNESCO and the EU which concluded in 2000, pedestrianising the entire area around the aqueduct and greatly improving the visitor facilities, including establishing a museum on the north bank. The project has been criticized for its cost (€33 million) and for the perceived loss of natural beauty of the surrounding landscape and area. During the redevelopment it was not possible to walk through the conduit at the top of the aqueduct; however guided crossings are now provided by the museum. The redevelopment has ensured that the area around the Pont du Gard is now much quieter due to the removal of vehicle traffic, and the new museum provides a much improved historical context for visitors.

The Pont du Gard is today one of France's top five tourist attractions, with 1.4 million visitors reported in 2001. The 19th century Roquefavour Aqueduct of the Canal de Marseille replicates the Roman architecture of the Pont du Gard.

Gallery

  • Pont du Gard Pont du Gard
  • From River From River
  • Typical markings on the Pont du Gard Typical markings on the Pont du Gard
  • Interior of the Pont du Gard's conduit Interior of the Pont du Gard's conduit
  • New (1743) bridge flanking the aqueduct New (1743) bridge flanking the aqueduct
  • Pont du Gard, 1850s Pont du Gard, 1850s
  • Pont du Gard, 2008 Pont du Gard, 2008

See also

References

  1. Bromwich, James (2006). Roman Remains of Southern France: A Guide Book. Routledge. p. 110. ISBN 9780415143585.
  2. ^ Langmead, Donald; Garnaut, Christine (eds.). Encyclopedia of architectural and engineering feats. p. 254.
  3. Bromwich, p. 112
  4. Bromwich, p. 111
  5. Bromwich, p. 112-113
  6. Deming, David (2010). Science and Technology in World History, Volume 1: The Ancient World and Classical Civilization. McFarland. p. 176. ISBN 9780786439324.
  7. Michelin Green Guide Provence. Michelin Travel Publications. 2008. pp. 297–298. ISBN 9781906261290.
  8. Fabre, G.; Finches, I.L. (1989). "L'aqueduc romaine de Nîmes et le Pont du Gard". Pour le Science (40): 412–420.
  9. O'Rourke Boyle, Marjorie (1997). Divine domesticity: Augustine of Thagaste to Teresa of Avila. Leiden: BRILL. p. 105. ISBN 9789004106758.
  10. ^ Le Pont du Gard remarquable Aqueduc, retrieved 2010-06-15
  11. Lamouroux, Gilbert, http://pagesperso-orange.fr/gilbert.lamouroux/, retrieved 2008-06-11 {{citation}}: Missing or empty |title= (help)
  12. Le Pont du Gard sur le plan technique, retrieved 2010-06-15
  13. http://auriol.free.fr/Perso/civera-seraphin.htm

External links