Roman Aqueducts were an ingenious feat of engineering developed by the Romans to transport fresh water in channels from outside sources to cities and towns across their territories.

The water they supplied was used for fresh drinking water, agriculture, bathing, and fountains. To keep water as fresh as possible, it was not stored after transportation in an aqueduct, but used to flush sewage in the cities of the Empire.

In Rome, aqueducts transported water over distances reaching over 92 kilometres. Although earlier civilisations, such as Persia, Egypt and India, had already developed the aqueduct, the Romans improved upon the design and built an extensive network of them the Empire over.

The remains of these can be seen across the world, from France to North Africa, and Spain to Turkey and in the UK.

• Building the Aqueducts
• Going Underground
• Water in the City
• Aqueducts in the UK

Building the Roman Aqueducts

The first Roman aqueduct was built in around 312 BC, and they continued to be built over the next 500 years, often at the request of Rome’s high-ranking politicians and Emperors using public and private funds.

The construction of aqueducts relied on one important factor: gravity. Roman engineers would design the channels to run from lakes and springs on a slight downward slope, allowing gravity to do its thing.

But prior to construction, a great deal of planning went into the construction of an aqueduct. Surveys, as well as investigations into land management and planning, were conducted to make sure that water would successfully travel at the right speed.

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If the water travelled too fast, it would wear down the stone over time, while if it were to travel too slowly, it would allow the water to stagnate and therefore cause it to become undrinkable.

Pressurised Syphons

At this planning stage, Roman engineers used tools such as the groma, the dioptra, and the chorobates.

The former was a vertical stick with a plumb line used to measure straight lines and angle, the second was a sighting tube used to measure angle, and the latter was was akin to a modern spirit level and used to measure slopes.

In some cases, the Romans used pressurised syphons to encourage water to travel uphill, though in the majority of cases, the benefits of gravity were used to their advantage, even if the water had to travel over many miles.

It was important that an aqueduct had the structural integrity to hold large amounts of moving water, something which they achieved with strong arch designs.

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This was even more crucial as the water was open to the air on the top of the arches, meaning that the water levels could increase with rain. To achieve this strength, aqueducts were constructed with stone, brick and volcanic cement.

Roman Aqueducts Going Underground

Although we are most familiar with aqueducts as large and imposing arched bridges on the landscape, acting as bridges and as part of canals, what is not often appreciated is that, on average, the only twenty-percent of an aqueducts total length was over-ground.

Engineers working on the aqueducts would construct complex underground pipe systems. This ensured their protection against erosion, and also limited their impact on the surrounding communities and agricultural fields.

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Slaves and paid workers would have worked tirelessly to dig holes deep into the ground along the planned route of the aqueduct.

Once established, these holes were then lined with clay to create waterproof pipes. In some cases, these clay pipes carried water from a spring to a city over some sixty miles.

Water in the City

Once water had arrived at the city from the aqueduct, it would be stored in a castellum, the a main water tank.

From here, a complex system of lead pipes would syphon water to secondary castella, before being carried in even smaller pipes to public baths and fountains, as well as (often wealthy) private homes.

Much like today, manholes and shafts for accessing this system of piping were established during construction to help workers to remedy any issues either during or after their installment.

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After the many years taken to construct an aqueduct, a Curator Aquarum would need to be installed to oversee the smooth running of the channel going forward, as well as to direct in its repairs or upgrade using slaves or paid workers.

For areas and pipes known to be damaged and in need of repair, workers would add sluice gates to redirect water around them.

Aqueducts in the UK

Aqueducts were constructed in Britain from the time of the Roman occupation (AD 43 onwards), with many still in use as late as the 5th century AD.

Remains of Roman aqueducts are especially concentrated around Hadrian’s Wall, though only 60 are now thought to survive throughout Britain.

If you would like to see a Roman aqueduct, or its remains, in person, you might like to begin in Dorchester, known in antiquity as Durnovaria.

Here, portions of the town walls and the remains of a Roman house can be viewed, alongside traces of the original aqueduct which ran through the ancient fortress.

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Or you might travel southwest to Lancaster, where you can see the remains of the Roman town Longovicium which was served by two aqueducts in antiquity.

Located on Dere Street, a major Roman road which ran from York up to the Antonine Wall in Scotland, Longovicium waas occupied between 150 and 400 AD and held a bathhouse, barracks, and headquarters, as was common of a Roman fort.

One of the two aqueducts feeding this town was fed from a dam which harnessed the water of as many as twenty-one springs.

To accommodate this great weight of water, the dam was built twenty feet high and 110 yards across, and was built of stone and clay to waterproof the interior. Today it is considered one of the best preserved aqueducts in Britain.

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Continuing the aqueduct tour, you can catch a glimpse of the aqueduct which once fed the Aesica Roman fort, constructed some time in the early 2nd century AD.

Not too far along in the ‘Great Chester’s, one might also travel to the Roman remains in Chester in the North-West of England. Originally known as Cilurnum, Chester’s Roman fort was built as part of the Hadrian Wall’s extensive structure in around 124 AD.

Until the end of the 5th century AD, around 500 of Rome’s soldiers were stationed here. The aqueduct which fed the fort in antiquity is still observable as an earthwork and as a buried feature. Running from Caw Burn to a location new Saughy Rigg, this aqueduct was built to be six miles long.

Similarly, the Aesica aqueduct ran six miles from Haltwhistle Burn to Caw Burn, where the other aqueduct for Chester took over.

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Finally, for something a little different, aqueduct hunters might like to take a trip to the valley of the River Cothi near Pumsaint in Carmarthenshire, Wales. Here, Roman gold mines, now owned by the National Trust, are located.

The local supply of fresh water in this area was put to good use by the Romans and an extensive system of numerous aqueducts was established. The longest of these is seven miles long, starting from its source at the gorge of the river.

These water systems proved useful for mining the gold veins hidden in the hillsides of the area, using an opencast technique. The mining appears to have begun before the establishment of the Cothi aqueduct in this area, for the structure was built over the mines.

Aqueducts after the Romans

As central authority depleted in the 4th and 5th centuries, aqueducts fell out of repair and use in the Middle Ages. Instead, urban populations relied on wells and local rivers for their water supplies, though in some monasteries, modest water systems were established.

The use of aqueducts was revived once again in 14th century Brugge, where a pumping system complete with a large cistern, as well as a wheel with buckets on a chain, served the population of 40,000.

Such pumping systems allowed water systems to develop at a rapid pace from the Renaissance onwards and today aqueducts, though impressive from an engineering perspective, have nonetheless lost their arched charm.