Follow the fascinating water route from the Uzès Aqueduct to Nîmes. An engineering masterpiece that has stood the test of time, leaving behind captivating stories. In this article, embark on a journey through the ages, explore every nook and cranny of this colossal work. From its monumental construction to its abandonment, prepare to be amazed by the technical prowess of this Roman jewel.
The origin of its construction
In the middle of the 20st century AD, the city of Nîmes was booming. It accommodated between 000 and 25 inhabitants, which was quite considerable for the time. During this period, Nîmes adopted the Roman way of life. Its public and private baths, as well as its fountains, are true symbols of refinement and comfort.
Cities like these are large consumers of water. They use this precious resource for all kinds of needs: domestic, social, political, and even for leisure. So, to meet this growing demand, Nîmes decided to build an aqueduct to transport water to the heart of the city. The aim is to offer the city even more possibilities, to create elegant fountains and luxurious thermal baths. All this with the idea of raising his status in the Roman Empire. Then begins the search for an adequate water source. The city decided to opt for the sources of the Eure, located near Nîmes, offering a regular and reliable flow.
Aqueduct identity sheet
- Age: built around 50 AD
- Construction duration: 10 to 15 years
- Duration of operation: approximately 5 centuries, from 50 AD to the beginning of the XNUMXth century
- Total length from Uzès to Nîmes: 50.01km
Pont du Gard identity sheet
- Total height: 48,77m
- Construction duration: estimated at less than 5 years
- Total volume of stones used: estimated at 21m000 (i.e. 3 tonnes)
Water captured in Uzès
The springs of Eure
During Antiquity, the waters of the Eure valley, made up of around ten sources, were channeled through a vaulted structure to supply the Nîmes aqueduct. At the start of its operation, this source located in Uzès delivered an impressive flow of 35 cubic meters of water per day to the aqueduct. A truly colossal quantity for the time!
The Plantéry basin is among the remarkable elements of this construction. With a surface area of approximately 1500 square meters and a volume of 4500 cubic meters, it is a Roman architectural marvel. Located in a limestone massif, it is fed by four griffins, a type of opening through which clear mineral water gushes out. And it's much more than just a water tank. It is used to filter the water from impurities before it continues on its way to the city. When the basin fills to overflowing, and to avoid any waste, technicians dump the water into the Alzon River.
The regulating basin
In 1992, the Eure Valley regulating basin was updated. It also reveals a crucial element of the hydraulic infrastructure of the Nîmes aqueduct. This basin is used not only to adjust the water flow necessary for the city, but also to carry out repairs when necessary. During its operation, approximately 5 billion cubic meters of water pass through it.
Formerly covered, the roof of the pool has disappeared over time. We also notice a slight shift in the stones in the center of the arch of the canal which supplies this basin. This phenomenon can be explained by past seismic activity which caused leaks in the structure.
The aqueduct and the Pont du Gard
The construction of the aqueduct, the incredible challenge
The source is located at 71,25 meters above sea level, while the Castellum de Nîmes is located at 58,94 meters. The builders therefore carefully studied the route of the aqueduct in order to bypass natural obstacles such as the plateau and the Gardon river. The aqueduct then covers a route of 50,01 km winding through the hills, thus avoiding the scrubland of Nîmes.
This technical prowess results in an almost flat slope over the entire course. Its height difference is only 12,27 meters between Uzès and Nîmes. On average, this represents less than 2,5 cm of elevation change every 100 meters, or 1 mm every 4,5 meters. Thanks to this, the water takes about a day and a half to travel the entire distance to Nîmes.
The aqueduct is primarily underground, which preserves the purity of the water and reduces evaporation. Inspection openings are provided along the route to allow cleaning and necessary repairs.
Gard's Bridge
Built around fifty years after Christ, the Pont du Gard is a marvel of Roman architecture. It has stood majestically above the Gardon River for more than two millennia. Considered the largest aqueduct project, it mobilized perhaps up to a thousand workers for three to five years.
The Pont du Gard fulfills a vital function by supporting part of the pipeline above the Gardon valley.
Today, it impresses with its 52 arches spread over three levels. With its height of 48,77 meters and nearly 275 meters in length at the third level, it is the highest Roman aqueduct bridge still standing to this day.
These huge blocks of stone, weighing up to 6 tonnes, are transported by water and land. They then require sophisticated lifting equipment like the goat. On the Pont du Gard, the pipeline is protected by slabs and measures on average 1,20 meters wide. Its interior walls are covered with a waterproof coating to preserve water.
Distributing water in Nîmes
The Castellum
The Castellum is a crucial building in ancient cities, responsible for distributing drinking water. At the time, it was topped by a structure with a dome and walls decorated with frescoes. However, it is one of the rare monuments of this kind that has reached us. In a remarkable state of conservation, it is comparable to that of Pompei.
Located high up, at 58,94 meters above sea level on a hill, the Castellum played an essential role in the XNUMXst century AD. The aqueduct carries water to this basin. This serves as a distribution center to the different districts of the city of Nîmes. Its aim is to guarantee the water supply, in addition to local sources and groundwater, especially during periods of drought. From this central point, lead pipes distribute water to public fountains, thermal baths, wash houses, and even the city's wealthy residences.
The abandonment of the aqueduct
Unfortunately, the Nîmes aqueduct only operated fully for around 140 years. Its use thus declined from the XNUMXrd century. The aqueduct was definitively abandoned in the XNUMXth century.
During research, it was discovered that the bottom of the aqueduct channel is not lined with waterproof material, unlike the side walls. This lack of coating led to significant water leaks through the masonry of the arches. This necessitated their rapid blocking shortly after the aqueduct was put into service.
In addition, the slope of the aqueduct is not uniform. As overflows cause problems in areas with low slopes, they threaten the stability of the Pont du Gard. To remedy this, builders erected a regulating basin upstream and raised the canal, adding cover slabs. They also added buttresses to the outer walls of the canal. This was probably done at the end of the first century or the beginning of the second century AD.
Then, towards the end of the third century, Nîmes' control of the aqueduct diminished. This allows owners of land crossed by the aqueduct to modify it as they wish, leading to the formation of carbonate deposits. Much later, after the first millennium, land owners used the aqueduct as a source of building materials. They recover its stones and carbonate deposits for various architectural projects, such as castles, Romanesque churches, homes and even cemeteries.
The Pont du Gard therefore stands out as one of the jewels of a remarkable ensemble, that of the Uzès-Nîmes aqueduct. This aqueduct bears witness to the ingenuity of ancient architects and builders. It is captivating in its quality and fascinating history.
Jean-Jacques Rousseau, writer and philosopher of the Enlightenment, discovered the Pont du Gard in 1737. Enthused by its unique architecture, he described his emotion in his autobiography Les Confessions:
It was the first work of the Romans that I had seen. I expected to see a monument worthy of the hands that built it. For once, the object passed my expectations and it was the only time in my life. It was up to the Romans alone to produce this effect. The art of this simple and noble work struck me all the more as it is in the middle of a desert where the silence and solitude make the object more striking and the admiration more vivid, because this so-called bridge does not was just an aqueduct.
Themes
