dimanche 5 août 2012

What have the Romans ever done for us? Well, there's the Pont du Gard


The story behind the Pont du Gard could easily have been a 21st Century one. It was a town planning drama which started in 45 BC when the Romans took over much of northwest Europe to create the colony, Gaul.
Within a hundred years, Nîmes had become a major centre in this new empire, a boomtown of 20,000 people. By 40 AD, the economic miracle was grinding to standstill for lack of water. The new affluence brought with it all the up market toys and luxuries of a consumer society. Unlike the locals, the Romans had baths.
Villas were no longer homes. They were executive homes with mains water. Soon, every square would have its fountain. Then new businesses and burgeoning administration attracted still more people from the countryside.
The local springs couldn’t cope with demand anymore. In today’s language, Nîmes was running out of bandwidth.
The nearest water supplies with sufficient capacity were in the mountains at Eure, some 20 kilometres to the north as the crow flies. But water follows the lie of the land. Avoiding the area’s twisted limestone hills and gorges would increase this distance to nearer 50.
At the heart of this civil engineering nightmare was a question - how to cross the valley of the River Gardon?
The scale of this enterprise is staggering even by today’s standards. Roman engineers designed a 50 km aqueduct which falls just 12 metres from beginning to end , allowing a smooth gravity-fed flow.
Local limestone was used to line the channels. Being porous, the stones were coated with mortar and lime to reduce water infiltration, parasites and root invasion.
Wherever there was a geological or topological obstacle the underground channel was progressively brought to the surface and continued on a support wall, arcades or over a bridge. To cross the River Gardon, they built the Pont du Gard.
At 49 metres, this is the highest aqueduct bridge ever built by the Romans and is remarkably well conserved.
It has 3 rows of arches: 6 on the bottom row, 11 on the second level and 47 on the top row. This is dry stone walling on a grand scale because the stones are precision cut to fit together – there’s no mortar.
Many pieces weigh over two tons and one wonders how they were lifted into position. The monument still bears traces of the project management of the work: numbering of stones, support points for scaffolding and lifting devices.
UNESCO declared the Pont du Gard a World Heritage Site in 1985. The site is now superbly serviced with multiple car parks, restaurants, museum, interpretive centre. There is excellent access for the disabled to the entire site. There’s also a network of footpaths and cycling trails so that visitors can enjoy not only the monument but also the surrounding landscape.
The 2000 year old pillars still bear the holes which held Roman scaffolding
Open all year round, the site is signposted from the A9 autoroute, exit 23 between Nîmes and Avignon.