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{{Infobox World Heritage Site
| WHS = Pont du Gard (Roman Aqueduct)
| Image = ]
| State Party = {{FRA}}
| Type = Cultural
| Criteria = i, iii, iv
| ID = 344
| Region = ]
| Year = 1985
| Session = 9th
| Link = http://whc.unesco.org/en/list/344
}}

The '''Pont du Gard''' is a notable ] ] ] that crosses the ] in southern ]. It is part of a {{convert|50|km|mi|abbr=on}} long aqueduct that runs between ] and ] in the ]. It is located in ] near ], in the ] '']''. The aqueduct was constructed by the Romans in the first century AD and was added to ]'s list of ]s in 1985. It is the highest of all Roman aqueduct bridges and is the best preserved after the ]. Today it is one of France's most popular tourist attractions.

==Description==
===The Nîmes aqueduct===
]
The Nîmes aqueduct originally carried water from a source at the Fontaine d'Eure near ''Ucetia'' (Uzès) to a delivery tank or ''castellum divisorum'' in ''Nemausus'' (Nîmes), from where it was distributed to fountains, baths and private homes around the city. Although the straight-line distance between the two is only about {{convert|20|km|mi|abbr=on}}, the aqueduct takes a winding route measuring around {{convert|50|km|mi|abbr=on}} to avoid the '']'' hills above Nîmes. The ''Garrigues'' are the southernmost foothills of the ]. They are difficult to cross, as they are covered in dense vegetation and indented by deep valleys,<ref name="Bromwich-110">{{cite book|last=Bromwich|first=James|title=Roman Remains of Southern France: A Guide Book|page=110|publisher=Routledge|year=2006|isbn=9780415143585}}</ref> and it was impractical for the Romans to attempt to tunnel through the hills. A roundabout course was therefore the only practical way of transporting the water from the spring to the city.

The Fontaine d'Eure, at {{convert|76|m|ft|abbr=on}} above sea level, is only {{convert|17|m|ft|abbr=on}} higher than the delivery tank or ''castellium'' in Nîmes, but this provided a sufficient gradient to sustain a steady flow of water to the 50,000 inhabitants of the city. The aqueduct's average gradient is only 1 in 3,000. It varies widely along its course, but is as little as 1 in 20,000 in some locations. The Pont du Gard itself descends {{convert|2.5|cm|in|abbr=on}} in {{convert|456|m|ft|abbr=on}}, a gradient of 1 in 18,241.<ref>{{cite book|last=Lewis|first=Michael Jonathan Taunton|title=Surveying instruments of Greece and Rome|page=187|publisher=Cambridge University Press|year=2001|isbn=9780521792974}}</ref> It is estimated that the aqueduct 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> that took nearly 27 hours to flow from the source to the city.<ref name="Sobin">{{cite book|last=Sobin|first=Gustaf|title=Luminous debris: reflecting on vestige in Provence and Languedoc|page=205|year=1999|publisher=University of California Press|isbn=9780520222458}}</ref>

]
The spring still exists and is the site of a small modern pumping station. It provides 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 during its journey through the conduit. This led to the flow of the aqueduct progressively becoming reduced by deposited carbonates.<ref name="Bromwich=112">Bromwich, p. 112</ref> Another threat was posed by vegetation penetrating the stone lid of the channel. As well as obstructing the flow of the water, dangling roots would introduce algae and bacteria that would decompose in a process called biolithogenesis, producing concretions within the conduit. It had to be maintained continuously by ''circitores'', maintenance workers responsible for its upkeep, who would crawl along the conduit scrubbing the walls clean and getting rid of any vegetation.<ref>Sobin, p. 217</ref>

Like most Roman aqueducts, much of it was built underground. It was constructed by digging a trench in which a stone channel was built and enclosed by an arched roof of stone slabs, which was then covered with earth. Some sections of the channel are tunnelled through solid rock. In all, {{convert|35|km|mi|abbr=on}} 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|abbr=on}} 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===
Built on three levels, the Pont is {{convert|49|m|ft|abbr=on}} high above the river at low water and {{convert|274|m|ft|abbr=on}} long. Its width varies from {{convert|9|m|ft|abbr=on}} at the bottom to {{convert|3|m|ft|abbr=on}} at the top.<ref name="Deming">{{cite book|last=Deming|first=David|title=Science and Technology in World History, Volume 1: The Ancient World and Classical Civilization|page=176|publisher=McFarland|year=2010|isbn=9780786439324}}</ref> The three levels of arches are recessed, with the main piers in line one above another. The span of the arches varies slightly, as each was constructed independently to provide flexibility to protect against subsidence. Each level has a differing number of arches:<ref name="Michelin">{{cite book|title=Michelin Green Guide Provence|publisher=Michelin Travel Publications|pages=297-298|year=2008|isbn=9781906261290}}</ref>

<center>
{| class="wikitable"
| '''Level'''
| '''Number of arches'''
| '''Length of level'''
| '''Thickness of piers'''
| '''Height of arches'''
|-
| Lower (1st row)
| 6
| {{convert|142|m|ft|abbr=on}}
| {{convert|6|m|ft|abbr=on}}
| {{convert|22|m|ft|abbr=on}}
|-
| Middle (2nd row)
| 11
| {{convert|242|m|ft|abbr=on}}
| {{convert|4|m|ft|abbr=on}}
| {{convert|20|m|ft|abbr=on}}
|-
| Upper (3rd row)
| 35 (originally 47)
| {{convert|275|m|ft|abbr=on}}
| {{convert|3|m|ft|abbr=on}}
| {{convert|7|m|ft|abbr=on}}
|}
</center>

The first level of the Pont du Gard adjoins a road bridge that was added in the 18th century. The water conduit or ''specus'', which is about {{convert |1.8|m|ft|abbr=on}} high and {{convert|1.2|m|ft|abbr=on}} 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 {{convert|5|mm|in|abbr=on}}. Over the centuries, this process has produced the deformation witnessed now.<ref>{{cite journal|author1=Fabre, G.|author2=Finches, I.L.|title=L'aqueduc romaine de Nîmes et le Pont du Gard|journal=Pour le Science|year=1989|number=40|pages=412-420}}</ref>

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.<ref name="Langmead" /> The masonry was lifted into place by ] with a massive human-powered treadmill providing the power for the winch. A complex scaffold was erected to support the bridge as it was being built. Large blocks were left protruding from the bridge to support the frames and scaffolds used during construction.<ref name="Michelin" /> The builders also left inscriptions on the stonework conveying various messages and instructions. Many blocks were numbered and inscribed with the required locations, such as ''fronte dextra'' or ''fronte sinistra'' (front right or front left), to guide the builders.<ref>{{cite book|last=Gimpel|first=Jean|title=The cathedral builders|page=75|publisher=Pimlico|year=1993|isbn=9780060911584}}</ref>

<div class="center">{{Image gallery
|title=Features of the Pont du Gard
|lines=3
|width=200
|Pont du gard v1 082005.JPG||Side view of the Pont du Gard, showing the three rows of arches
|Pont du Gard stonework.jpg||Stonework on the Pont du Gard, showing the protruding blocks that were used to support the scaffolding
|Aqueduc pont du gard.jpg||Interior of the water conduit of the Pont du Gard
}}</div>

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 ] incorporating minute shards of pottery and tile. It was painted with olive oil and covered with ''maltha'', a mixture of ], pork grease and the viscous juice of unripe figs. This produced a surface that was both smooth and durable.<ref name="Boyle">{{cite book|title=Divine domesticity: Augustine of Thagaste to Teresa of Avila|last=O'Rourke Boyle|first=Marjorie|page=105|date=1997|publisher=BRILL|location=Leiden|isbn=9789004106758}}</ref>

The Pont du Gard's design represents a fairly early stage in the development of Roman aqueducts. Its designer's technique of stacking arches on top of each other is clumsy and expensive, as it necessitates the use of a very large amount of stone. Later aqueducts had a more sophisticated design, making greater use of concrete to reduce their volume and cost of construction. The ] and the ] are of roughly similar length but use far fewer arches. Roman architects were eventually able to do away with "stacking" altogether. The ] in ] and a similar aqueduct near ], ] utilise tall, slender piers, constructed from top to bottom with concrete faced with masonry and brick.<ref>{{cite book|last=Hill|first=Donald Routledge|title=A history of engineering in classical and medieval times|date=1996|publisher=Routledge|isbn=9780415152914}}</ref>

==History==
The construction of the aqueduct has long been credited to ]' son-in-law and aide, ], around the year 19 BC. At the time, he was serving as ], the senior magistrate responsible for managing the water supply of Rome and its colonies. Emile Espérandrieu, writing in 1926, linked the construction of the aqueduct with Agrippa's visit to ] in that year.<ref>Bromwich, p. 110</ref> Newer excavations, however, suggest the construction may have taken place between 40 and 60 AD. Tunnels dating from the time of Augustus had to be bypassed by the builders of the Nîmes aqueduct, and coins discovered in the outflow in Nîmes are no older than the reign of the emperor ] (41-54 AD). On this basis, a team led by Guilherm Fabre has argued that the aqueduct must have been completed around the middle of the 1st century AD.<ref>Fabre, G, Fiches,J.-L., and Paillet, J.-L. 1991. "Interdisciplinary Research on the Aqueduct of Nimes and the Pont du Gard." ''Journal of Roman Archaeology'' 4, 63-88.</ref> It is believed to have taken about fifteen years to build, employing between 800 and 1,000 workers.<ref name="pontdugard2">{{Citation | last = | first = | author-link = | last2 = | first2 = | author2-link = | title = Le Pont du Gard remarquable Aqueduc| date = | year = | url = http://www.pontdugard.fr/page.php?langue=FR&m=3_2| accessdate = 2010-06-15}} </ref>

From the 4th century onwards, the aqueduct's maintenance was neglected as successive waves of invaders disrupted the region.<ref name="Boyle" /> It became clogged with debris, encrustations and plant roots, greatly reducing the flow of the water. The resulting deposits in the conduit, comprised of layers of dirt and organic material, are up to {{convert|50|cm|in|abbr=on}} thick on each wall.<ref>{{cite book|last=Homer-Dixon|first=Thomas F.|date=The upside of down: catastrophe, creativity, and the renewal of civilization|page=237|publisher=Island Press|year=2006|isbn=9781597260657}}</ref> Nonetheless it seems to have continued to supply water to Nimes until as late as the 9th century.<ref name="Cleere">{{cite book|last=Cleere|first=Henry|title=Southern France: an Oxford archaeological guide|page=96|publisher=Oxford University Press|year=2001|isbn=9780192880062}}</ref>

Although some of its stones were plundered for use elsewhere, the Pont du Gard remained largely intact. Its survival was due to its use as a ] across the valley. In the 13th century the French king granted the ]s of Uzès the right to levy tolls on those using the bridge. The right later passed to the Bishops of Uzès. In return, they were responsible for maintaining the bridge in good repair.<ref name="Cleere" /> However, it suffered serious damage during the 1620s when ] made use of the bridge to transport his artillery during the wars between the French royalists and the ]s, whom he led. To make space for his artillery to cross the bridge, the duke had one side of the second row of arches cut away to a depth of about one-third of their original thickness. This left a gap on the lowest deck wide enough to accommodate carts and cannons, but severely weakened the bridge in the process.<ref name="Rennie">{{cite journal|title=Description of the Pont du Gard|last=Rennie|first=George|journal=Minutes of proceedings of the Institution of Civil Engineers|volume=14|page=238|date=1855}}</ref>

], 1804, showing the dilapidated state of the bridge at the start of the 19th century]]

In 1702 the local authorities renovated the Pont du Gard to repair cracks, fill in ruts and replacing the stones lost in the previous century. A new bridge was built by the engineer ] in 1743-47 next to the arches of the lower level, so that the road traffic could cross on a purpose-built bridge.<ref name="Langmead" /><ref name="Rennie" /> However, the Pont du Gard continued to deteriorate and by the time ] saw it in 1835 it was at serious risk of collapse from erosion and the loss of stonework.<ref name="Bromwich-117">Bromwich, p. 117</ref>

]'s admiration for all things Roman led to him visiting the Pont du Gard in 1850. He approved plans by the architect Jean-Charles Laisné to repair the bridge, a project which was carried out between 1855-58 with funding provided by the Ministry of State. The work involved substantial renovations that included replacing the eroded stone, infilling some of the piers with concrete to aid stability and improving drainage by separating the bridge from the aqueduct. Stairs were installed at one end, allowing visitors to walk along the conduit itself. <ref name="Bromwich-117" />

There have been a number of subsequent projects to consolidate the piers and arches of the Pont du Gard. It has survived three serious floods over the last century; in 1958 the whole of the lower tier was submerged by a giant flood that washed away other bridges,<ref name="Bromwich-117" /> and in 1998 another major flood affected the area. A further flood struck in 2002, badly damaging nearby installations.

==Tourism and visitors==

The Pont du Gard has been a tourist attraction for centuries. 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 ]), many of whom have left their names on the stonework. From the 18th century onwards, particularly after the construction of the new road bridge, it became a famous staging-post for travellers on the ] and became increasingly renowned as an object of historical importance and French national pride.<ref>{{cite book|last=Stirton|first=Paul|title=Provence and the Côte d'Azur|page=116|year=2003|publisher=A&C Black Publishers Ltd|isbn=039330972X}}</ref>

The Pont du Gard was added to ]'s list of ]s 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."<ref name="Langmead" /> By this time, however, the site was congested with vehicle traffic – which was still allowed to drive over the 1743 road bridge – and cluttered with illegally built structures and tourist shops. As the architect ] put it, the "appetite for gain" had transformed the Pont du Gard into "a fairground attraction".<ref>{{cite book|title=Architecte|last=Viguier|first=Jean-Paul|page=11|publisher=Odile Jacob|year=2009|isbn=9782738123046}}</ref>

In 1996 the General Council of the Gard ''département'' began a major four-year project to improve the area, sponsored by the French government, in conjunction with local sources, UNESCO and the ]. The entire area around the bridge was pedestrianised and a new visitor centre was built on the north bank to a design by Jean-Paul Viguier. 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 ] of the ] replicates the Roman architecture of the Pont du Gard.

==See also==
*]
*]
*]
*]

==References==
{{reflist}}

==External links==
{{Commons|Pont du Gard}}
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* {{structurae|id=s0000256|title=Pont du Gard}}
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Latest revision as of 08:22, 6 September 2010