The 11 ancient Aqueducts

Ancient Rome was an incredible city; of that there is no doubt. The Romans themselves were an amazingly technical people; they were able to perform feats of construction and engineering of which we today are still in awe. The many buildings, roads and bridges in Rome and in Italy and the rest of the old Empire are ample testament to their abilities.

The aqueducts are another. Often overlooked, the remains of the 11 ancient Roman aqueducts are a fascinating example of ancient engineering.

aqueduct arcade These were the ancient Roman aqueducts and construction dates.

  1. Aqua Appia - started 313 BCE
  2. Aqua Anio Vetus - started 273 BCE
  3. Aqua Marcia - started 144 BCE
  4. Aqua Tepula - started in 127 BCE
  5. Aqua Julia - started in 33 BCE
  6. Aqua Virgo - started at roughly the same time. Both the Virgo and the Julia were built by Marcus Agrippa to add to the Roman drinking water supply (Julia) and as a water source for his baths (Virgo).
  7. Aqua Aliestina - Built by Augustus, so its construction start would be around the last decade BCE to the first decade ACE. Used for filling his private naumachia (simulated naval battles) lake.
  8. Aqua Claudia - started in 36 ACE by Caligula. Completed in 50 ACE by Claudius.
  9. Aqua Anio Novus - Same as the Claudia
  10. Aqua Trajana - started in 111 ACE by Trajan
  11. Aqua Alexandrina - built by Alexander Severus in the 210's -220's ACE.

There were a few others as well, bringing the total of all aqueducts in the Greater Ancient Rome area to 14. The majority of them had their beginnings in the eastern hills and followed a roughly east-west or southeast-northwest route into the city.

While our modern image of aqueducts are of the Pont du Gard outside Nîmes, France, most aqueducts into the city of Rome spent the majority of their length underground. Aqueducts were maintenance-intensive works; Roman crews were constantly repairing and cleaning them. The mineral content of the water would form large calcium carbonate deposits on the insides of the channels that would have to be removed by hand. For the underground portions, Roman crews would have to climb down vertical access shafts that were cut into the hills the aqueducts were built to flow through. These shafts were close together, maybe every 200 meters or so. Today, in the countryside outside Rome it is possible to see a few of these shafts exposed; modern road building or other earth-moving projects exposed the ancient works. It is also possible to find intact shafts with their original marking stones and covers.

aqueduct arcade I can't imagine climbing down those shafts, using handholds cut into the rock to clean a channel no more than 1.5 meters high (if that) with only torch light for illumination. I guess I'd just send my slaves down there for me.

Aqueducts often had sharp turns in them. The turns slowed the water flow and allowed the larger sediment to settle out. An aqueduct would almost always terminate in large cisterns, or water tanks. The tanks were used as pressure regulators, settling tanks and distribution network nodes. Fountains were used as a public water supply and were how the common people acquired their water. Rich people had a pipe into their homes with a valve at the end. Very modern sounding, isn't it?

The structure that kept an aqueduct's channel elevated above ground is called an arcade. The aqueduct itself was a channel built on top of the arcade. The channel may have been built of stone blocks or bricks and was lined with cement. An aqueduct had to have a nearly constant slope from its source to its final destination to allow for correct water flow and to reduce wear and tear on the structure. You can imagine that a stream of water that had flowed steadily and in a straight line for 20 miles would build up a lot of kinetic energy.

The Roman mathematics system was not very advanced (imagine doing multiplication with Roman numbers: X * II = XX) but they understood basic engineering principles. They used some simple tools to mark off the path of the aqueduct, including a template to maintain the slope. Hydraulic engineers would have to mark off the height of the channel every few meters thousands of times from termination point to start point.

The termination point determined how high the arcade had to be. An aqueduct whose final terminus was on the Palatine Hill would have to start out much higher at it's source than one terminating at the modern Piazza di Spagna or at Agrippa's baths.

Water quality varied from excellent (Aqua Claudia, Aqua Marcia) to not suitable for human consumption (Aqua Anio Vetus, Aqua Aliestina).

Modern Traces of Ancient Works

The ancient system was quite complex and no doubt enormously impressive. Even the invading Goths and Visigoths and Ultra-MegaGoths knew what they had with the aqueducts. The Germanic rulers preserved them as best they could, repairing them after they had damaged them as a part of laying siege to the city. A legendary story has one invading army using the aqueducts as a way to sneak into Rome. Apparently they were unsuccessful. There are a few sections of aqueduct remaining; none are still being used, however.

aqueduct arcade The Aqua Virgo came into the city from the east and then turned south. It made a sharp right turn at the very spot the Trevi Fountain is at now. It crossed the Via Lata (now Via del Corso) with a beautiful marble faced gate and terminated in the Pantheon area to supply Agrippa's baths. Parts of its arcade are still visible in the surrounding neighborhood, off Via di Tritone. A frieze up near the top of the fountain is a scene depicting two Roman soldiers being shown a spring by a young girl, thus echoing the ancient aqueduct's path and turn there.

The Piazza di Spagna area in ancient times contained several huge cisterns to catch the water from several aqueducts. The cisterns then used a series of lead pipes (in standard sizes, by the way) to distribute the water. The "boat fountain" at the foot of the Spanish Steps is still fed by the ancient pipes (but not the aqueduct).

One day after we had wandered around San Giovanni in Laterano, we crossed the street to look at La Santa Scala (the Holy Stairs). Immediately next to the building housing the stairs was an aqueduct arcade. A quick look at the map told us this was the "Acquadotto Neroniano". The map name threw me off at first - there never was an actual aqueduct named "Neroniano" (in Italian, "Neronius" in Latin). In fact, what we were looking at were two aqueducts stacked on top of each other - the Aqua Claudia and the Aqua Anio Nova. The aqueduct we followed is called the "Acquadotto Nerniano" on the map because Nero rebuilt that part of the structure back before he went looney tunes. It terminated on the Caelian hill, at the temple of Claudius.

We decided to follow the arcade for a while and eventually found ourselves at Porta Maggiore. Porta Maggiore looks like an city entrance gate but was in fact a confluence of two aqueducts - The Claudia and the Anio Novus - and made to look fancy since that is where they all crossed the Via Praenestina and the Via Labicana, two major roads out of town. Eventually, centuries later, the aqueduct arcade was incorporated into the hastily built Aurelian wall. That wall is still present today.

The Aqua Marcia and two others also cross there, but at 90 degrees to the wall. One can see the channels for those aqueducts in the wall that extends from the Porta Maggiore back to where we first started following it.

This site has a cool semi-interactive map that allows you to pick an aqueduct and see it's route from start to finish. If you know the city really well you can locate each aqueduct's course in the modern city plan. This site (coincidentally a Telespazio site!) has some good photos of some water works. The text is in Italian, but you can use Altavista's Babelfish if you want. This site also has some interesting information.

Forum Boarium

The area between the Tiber River, the Capitoline Hill and the Palatine Hill has always been extremely important, even in pre-urban times. The area was originally marshland and was reclaimed in the time of the Etruscan kings. The Forum Boarium, the cattle market, was located here because of it's proximity to the wharves and docks of the Tiber. This area was also the intersection of the Via Salaria and the Tiber River, two important trade routes in the ancient Roman world.

The Temple of Portunus and the Temple of Hercules Victor

The Temple of Portunus was consecrated to the god Portunus, the protector of sailors and ports. It was built in the 6th century BCE and restored in the 1st century BCE. It remains today in a remarkable state of preservation and is an excellent example of a "typical" (if there is such a thing) Roman temple.

The temple of Hercule Victor is of an unusual design; it's round. Most Roman temples were rectangular. The only other round temple I know of in the Rome area is the Temple of Vesta in the Roman Forum, but there is literally only a fragment of that structure left. The Temple of Hercules Victor was built by an olive oil merchant in the 2nd century BCE. This building, too is in excellent shape and is the oldest temple in Rome made of marble. The temple was converted into a church. Its interior contains fragments of frescoes from the 15th century.

Theater of Marcellus

theater of marcellus The Theater of Marcellus is not really in the Forum Boarium area, but it's close and I want to discuss it, so here it is.

The Theater of Marcellus was started by Julius Caesar and completed by Augustus in 13 BCE. It was only the third permanent theater in Rome. Apparently the Roman Establishment felt that theatrical entertainment had a negative affect on their society's collective morality. Gladiator combats were just fine, but acting singing and poetry wasn't?

The Theater of Marcellus exterior design consists of three tiers, each with different column types. The first tier was Doric, the second tier Ionic and the now-lost-to-us third tier was Corinthian.

I've read various sources that indicate that the Colosseum's exterior echoed the theater's for several reasons. Vespasian, by echoing the exterior design of the Theater of Marcellus in the Colosseum was able to link his reign to that of Augustus. Additionally, the order of columns in the tiers was considered to be the most aesthetically pleasing and the penultimate expression of Roman classicism.

It has been used heavily for it's entire existence; it was converted into a fortress in the 12th century and became a palazzo in the 16th. The palazzo was at some point turned into apartments; people live in it today. Whenever I walk by it at night I see lights behind the windows. The theater looks really great these days; like so many other buildings in Rome it received the Jubilee scrub down a year or so ago and now gleams brightly white in the sun.

Here are the photos.