An aqueduct is a channel or pipe used to transport water from a remote source to a desired location, such as a town, city, or agricultural area. The simplest, most primitive form of aqueduct was used in early Egypt, Assyria, and Babylon. It consisted of nothing more than an open canal dug between the river and the city where water moved by gravity alone. More complicated aqueducts were later developed in Persia (modern-day Iran), but it was the Romans that turned this necessity into spectacular architectures and engineering marvels that survive to this day.
The Romans constructed aqueducts to bring a constant flow of water into cities and towns, supplying public baths, fountains and private households. The aqueducts were built from a combination of stone, brick and the special volcanic cement pozzuolana. While the great archways leave a definite impression, the bulk of the Roman waterway system ran below ground. Channels bored through rock, or dug below the surface carried water where it was convenient and possible. Only where valleys or lowlands intervened, the conduit was carried on bridgework, or its contents fed into high-pressure lead, ceramic or stone pipes and siphoned across. Of the approximately 415 km in the aqueduct system present, only about 48 km consisted of the visible, mammoth arched structures.
Here are 5 of the most well preserved aqueducts of the ancient Roman Empire.
Aqueduct of Segovia
The Aqueduct of Segovia is one of the most significant and best-preserved ancient monuments left on the Iberian Peninsula, in Spain. The aqueduct is the city's most important architectural landmark and was in operation right to the 20th century. The aqueduct transported waters from Fuente Fría river, situated in the nearby mountains, some 17 km from the city. It runs another 15 km before arriving in the city.
At its tallest, the aqueduct reaches a height of 28.5 m including nearly 6 m of foundation and supported by a total of 167 arches.
The aqueduct is built of unmortared, brick-like granite blocks. During the Roman era, each of the three tallest arches displayed a sign in bronze letters, indicating the name of its builder along with the date of construction. Today, two niches are still visible, one on each side of the aqueduct. One of them is known to have held the image of Hercules, who according to legend was founder of the city. The other niche now contains the images of the Virgen de la Fuencisla (the Patroness of Segovia) and Saint Stephen.
Pont du Gard
The Pont du Gard crosses the Gardon River in Remoulins, in southern France. It is part of the Nîmes aqueduct, a 50 km-long structure built by the Romans to carry water from a spring at Uzès to the Roman colony of Nemausus (Nîmes). Built in the 1st century AD, the Pont du Gard is the highest of all Roman aqueduct bridges and is the best preserved after the Aqueduct of Segovia.
The bridge stands 48.8 m tall and descends by a mere 2.5 cm – a gradient of only 1 in 3,000 – which is indicative of the great precision that Roman engineers were able to achieve using only simple technology. The whole aqueduct itself descends in height by only 17 m over its entire length of 50 km.
The aqueduct is estimated to have carried 200,000 cubic meter of water everyday to the fountains, baths and homes of the citizens of Nîmes. It continued to be used possibly until the 6th century, with some parts used for significantly longer, but lack of maintenance after the 4th century meant that it became increasingly clogged by mineral deposits and debris that eventually choked off the flow of water.
After the collapse of the Roman Empire and the aqueduct's fall into disuse, the Pont du Gard remained largely intact due to the importance of its secondary function as a toll bridge. For centuries the local lords and bishops were responsible for its upkeep in exchange for the right to levy tolls on travellers using it to cross the river, although some of its stones were looted and serious damage was inflicted on it in the 17th century. It attracted increasing attention starting in the 18th century and became an important tourist destination. It underwent a series of renovations between the 18th and 21st centuries, commissioned by the local authorities and the French state, that culminated in 2000 with the opening of a new visitor centre and the removal of traffic and buildings from the bridge and the area immediately around it. Today it is one of France's most popular tourist attractions.
The Valens Aqueduct was believed to have been built by the Roman Emperor Valens in the late 4th century AD, whose name is borne by the aqueduct. It was restored by several Ottoman Sultans later, and is one of the most important landmarks of the city.
The Valens aqueduct, which originally got its water from the slopes of the hills between Kağıthane and the Sea of Marmara, was merely one of the terminal points of a complex system of aqueducts and canals. The total length of the network exceeds 250 kilometers - the longest such system of Antiquity - that stretched throughout the hill-country of Thrace and provided the capital with water.
The Aqueduct of Valens had a length of 971 meters and a maximum height of 29 meters with a constant slope of 1:1000. Except for a bend to allow the the construction of the Fatih Mosque, the aqueduct runs perfectly straight. The aqueduct stands in Istanbul, in the quarter of Fatih, and spans the valley between the hills occupied today by the Istanbul University and the Fatih Mosque. The surviving section is 921 meters long, about 50 meters less than the original length.
Pont de les Ferreres
The Pont de les Ferreres also known as Pont del Diable in Catalan or Devil's Bridge in English is a 249 meter long aqueduct that is part of the Roman aqueduct built to supply water to the ancient city of Tárraco, today Tarragona, in Catalonia, Spain. The Tárraco aqueduct took water from the Francolí river and fed the population of Tarragona, 15 kilometers south of the river.
The date of construction of the aqueduct is uncertain. Some believe that it was built during the era of Augustus in 1st century AD, a date which coincides with the date of expansion of the city. The aqueduct was in use until the Middle Ages, during which it was repaired several times, including in the 10th century under Abd ar-Rahman III., Caliph of Córdoba. Various measures aimed at the preservation of the buildings were carried out in the 18th to the 20th century.
Acueducto de los Milagros
The Acueducto de los Milagros is a ruined Roman aqueduct bridge, part of the aqueduct built to supply water to the Roman colony of Emerita Augusta, today Mérida, Spain.
Only a relatively small stretch of the aqueduct still stands, consisting of 38 arched pillars standing 25 meters high along a course of some 830 meters. The structure originally brought water to the city from a reservoir called the Lago de Proserpina, fed by a stream called Las Pardillas, around 5 km to the north-west of Mérida.
It is thought to have been constructed during the 1st century AD, with a second phase of building (or renovations) around 300 AD. In later centuries, the inhabitants of Mérida dubbed it the "Miraculous Aqueduct" for the awe that it evoked.
The aqueduct is preserved as part of the Archaeological Ensemble of Mérida, a UNESCO World Heritage Site
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