Roman Water Infrastructure
The Roman water infrastructure consisted of four main areas, water conduction, drainage of
lands, canals, and harbors. The area which will be given the most attention is that of
water conduction, however, the other three areas are also very interesting. The Roman
system for water conduction, at it's peak at around 300 AD, consisted of 11 aqueducts.
These 11 aqueducts supplied the city with approximately 1,168,850 cubic meters of water
per day. This is an astounding number compared to today's standards, averaging out to
about 200 gallons per person per day.
By the end of the third century BC it became necessary to regulate the torrential floods
of the Tiber River. This was done by enclosing the river in stone embankments laid out in
stepped stages. This method proved to be very effective, and was also used to regulate the
Other notable efforts were accomplished in the drainage of land for farming. In 280 BC
Manius Curius Dentalus drained the marshes of Rieti by cutting a 2,624-foot-long canal
which was led deliberately to a precipice, forming a dramatic waterfall. In 109 BC work on
reclaiming the Po Valley was begun under the direction of Aemilius Scaurus for the purpose
of settling veteran soldiers as farmers. This was done by cutting a system of canals
through the valley which were also used for navigation. The reclamation in this previously
uninhabitable area went on for hundreds of years. This fertile area, known as Cisalpine
Gaul, became the "cockpit of creativity in the western world."
One notable project involving roman reclamation efforts can be found in the Facinus
Emissarium. This was a project ordered by Emperor Claudius which involved lowering the
level of the Lacus Fucinus in order to gain approximately 38,000 acres of new farmland.
This project required the digging of a 3.5 mile long tunnel through rock. The tunnel was
completed after 30,000 men labored for 11 years.
The enormous and monumental works accomplished under the Roman Empire were largely a
result of totalitarian power. It was the availability of free labor provided by slaves,
and the ability of the Emperor to exert his totalitarian power which made possible these
capital and labor intensive projects. The aqueducts of Rome are an extraordinary example
of engineering. What remains of these great structures are monuments of construction that
was well ahead of its time.
At its peak, Rome's system of 11 aqueducts measured 312 miles long, with 262 miles
consisting of underground tunnels, and the rest being arched structures. The total
capacity of this system was approximately 1 million cubic meters of water every 24 hours.
To put this in perspective, the present day District of Columbia is about the same size
Rome was in AD 300, and can provide roughly 67 gallons of water per person. The aqueduct
system in Rome in AD 300 provided an estimated 200 gallons of water per person. A lot of
this water was used to supply public fountains and baths. These figures are astonishing,
and reflect the vast size and excellent overall quality of the Roman water network.
Building an aqueduct involved one main concern; leveling. When an aqueduct followed a
river, the grade of the river could be followed and used as a reference. However, when the
Roman engineers had to construct aqueducts through the hills, maintaining the correct
gradient became more difficult. The leveling was done using a tool called the chorobates,
which was a 20 foot long board that could be leveled with a plumbline, or by filling a
groove cut in the top with water. Using this tool an experienced tunnel builder could
establish a grade with an accuracy of 1:2000.
In order to maintain grade over river crossings and gorges, spectacular arched bridge
constructions called viaducts were built to carry the conduit. The size of some of these
structures was astounding. Due to the large above ground structures, and the amount of
tunneling that was required to complete an aqueduct, these projects usually took many
years, and involved mobilizing hordes of workers. The enormous labor force consisted of
slaves, or prisoners of war. Because the overseers of such projects realized that better
treatment resulted in better performance, these slaves were treated very well, and many
were eventually integrated to became Roman citizens.
When the aqueducts were cut in soft ground they were lined with masonry. When they were
cut through rock they were left unlined. The above ground arches were built entirely of
stone in the earlier aqueducts, but in the later aqueducts the main specus was made of a
rough concrete, and faced with stone. At the source of each aqueduct there was a settling
tank to remove solids from the water preventing the clogging or silting up of the
conduits. In the city each aqueduct ended in a castellum, or distribution basin. This
basin had three outlets at the lower level which served fountains, baths, and public
buildings, and higher up in the basin were the outlets that served private consumers.
Overflow was used to flush drains, or turn water wheels.
Most of what is currently known about the Roman system of aqueducts was derived from a
book written by Sextus Julius Frontinus, who served as the Curator Aquarium from AD 97 to
AD 104. He was appointed to this office by Nerva in order to restore the long neglected
and abused water system. Frontinus was very instrumental in restoring the aqueducts, and
doing away with the corruption, and fraudulent practices that had left the system in a
state of disrepair.
Frontinus kept very accurate records, by taking inventory of the entire system, and
detailing the technical aspects of how such a system should be maintained. After
correcting all of the problems that had occurred, Frontinus began making improvements to
the system in order to make it more efficient. In order to ensure that the work he had
done would continue when he left office, Frontinus set a standard to be followed, and
wrote a number of bills that were enacted by the Roman Senate.
Just as all great things must come to an end, so did the Roman system of aqueducts. As was
pointed out previously, with a water distribution system of this scale, a continuous
maintenance effort is required. Otherwise the system will deteriorate and fall into
disrepair and disuse. When the Roman economy went into decline, so did the water
The final destruction of the Roman system of aqueducts occurred in 537 AD during a siege
on Rome by the Goths. The Goths built an encampment between two lines of arches of the
Aqua Claudia, and the Anio Vetus, in which they housed 7,000 troops. From this
fortification they conducted raids on Rome, and demolished the aqueducts in an effort to
deprive the city of water. They even attempted to send troops through the dry conduits to
attack the city. After the siege, there was an effort to repair the aqueducts, but they
eventually fell to disrepair and neglect, with the exception of Aqua Virgo, which remains
in use today.
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