ABSTRACT
One of the most finely preserved aqueduct systems in the Roman world is that which brought water to Nimes from springs 50 km away. It was built by Agrippa between 20-16 BC. Most of the channel is below ground or carried on a low wall and the water runs down a slope which has been calculated as 1 in 3,000 over the whole distance. To carry it across the gorge of the river Gardon, the famous 'Pont du Gard' was built, 269 metres long and 49 metres high (fig. 138). The proportions are simple: four units for the central arch, three for the lateral arches and one for the upper tier of arches, and six for the overall height. The bridge is slightly curved against the flow of the stream, and the wide central arch spans the stream itself so that no abutments are actually in the river bed. The bridge is built entirely of stone, with no clamps or mortar, some individual stones weighing up to six tonnes each. The many projecting bosses are left to support scaffolding for maintenance of the bridge. When the water arrived in Nimes it flowed into a large circular basin with a settling tank and a series of outlets through which the water was fed to the various parts of the town.
