Roman Aqueducts: An Engineering Brilliance
Transportation of water is a very important obstacle the world has taken on. Water is a necessity to live; therefore control of water in and out of towns has been going on for thousands of years. Many different ways of moving water from one spot to another have been tried over the years. One example is the building of dams, not only to generate electricity, but also to create an abundance of water that can be transported to farmers to water their crops. The water from the dam is sent through underground conduits, aqueducts, to its final destination. Aqueducts were used by Greeks, Assyrians, Babylonians, Persians and Egyptians for water transportation. These early civilizations provided the vision for the Roman Empire to perfect the use of the aqueduct.
In 97 AD, Sextus Julius Frontinus, the city official in charge of the water supply, is recorded as saying:
I ask you! Just compare this vast array of indispensable structures carrying so much water with the idle Pyramids or the world-famous but useless monuments of the Greeks. ( )
In 97 AD, 300 gallons of water per person a day flowed into Rome through nine aqueducts. The Romans had succeeded in their vision of an aqueduct system supplying Rome with water. Many people, including Frontinus, thought that the Roman aqueduct system was the greatest invention in the world because of what it brought to the people of Rome. In the early days of Rome, the water supply came from the River Tiber. The Tiber, however is a very muddy river, and Romes sewer system also contaminated it. By the 4th century the Roman population was growing rapidly and Rome urgently needed an alternate water supply. In 312 BC the Roman Senate ordered Adile Appius Claudius to find a new source of water for the city. Claudius undertook the mission and started construction of the first aqueduct into Rome (Carr). Aqua Appia was successfully completed and over the next 500 years, ten more aqueducts were constructed in Rome. At completion of the last aqueduct into Rome, an estimated 38 million gallons of water flowed into Rome everyday! The Roman Empire also built many other aqueducts in Greece, Italy, France, Spain, North Africa, and Asia Minor. Even today some of the beautiful arches of the aqueducts can be seen.
Construction of the Roman Aqueduct started with finding a suitable source of water fairly close to the town that needed the water. This source usually came from underground springs for which the Romans had to search. After water was found, the aqueduct was commissioned to be built and a surveyor was hired to find the most practical route. The aqueducts gradient was usually around one foot drop per two hundred feet in length. By choosing the gradient and maintaining it along the entire length of the aqueduct, the water could be made to flow fast enough to ensure a good supply, yet not so fast that the force of the rushing water washed out the aqueducts and pipes (Myron). Getting this precise gradient required measurements by the surveyor. After the surveyor calculated the length of the aqueduct, and the overall fall, construction could then start.
Work on the aqueduct would begin concurrently at various points along the route. Once a channel had been dug, a chorobate would be lowered into the trench to check the slope. The chorobate was a ten-foot long wooden trough with a long grove running down its middle where water was poured; the water indicated when something was level. Once the route was the right gradient the water channel was lined with concrete or a pipe was put into the ground. Underground aqueducts made up about 90% of the 313 total miles of aqueduct into Rome.
Above Ground Aqueducts
When an aqueduct came to a valley, it was no longer possible to keep the required gradient underground; therefore the Romans designed a bridge like structure of arches that spanned over the valley. When you think of the Roman aqueducts, you think of these beautiful structures, but only about 10% of all aqueducts leading to Rome were above ground. These aqueducts were engineering feats. The structure was a series of arches that were built together. Sometimes, when a very high aqueduct was needed, there were three courses of arches, one on top of the other, with the arches becoming smaller toward the top. This stacking of arches was done because of stability reasons and it proved to work because some of the aqueducts are still standing today.
One of the Romans greatest engineering feat is the design of the arch. Before the Romans, the bridges that were built were usually a flat piece of stone spanned over a space between two upright supports. The problem with this design is that a heavy weight on the middle of the span put too much stress on the stone and broke it. The Romans solved this problem by designing the arch. When a heavy weight is on the arch, the stones compress into each other and into a solid foundation, thus making the structure stronger. The Romans used the arch in their designs of aqueducts, bridges, and buildings, many of which are still standing today. (BCIT)
The Romans were the first civilization to make a mortar that did not disintegrate when exposed to water. They found natural cement near the Italian town of Pozzuoli and mixed the cement with lime, sand, and water to form the mortar. The mortar was used by Roman Engineers in aqueducts, as a binder in piers and arches, and for foundations. In the arch, stones were held together with the mortar. The arch sat on a solid foundation and the stones were stacked up and mortared together so the axial forces between the stones would transfer the load into the foundation. Therefore the arch could withstand a large amount of force. The top of the aqueduct was lined with cement and covered by stones to protect the aqueduct from contamination and poisoning from enemy troops. (BCIT)
When the water reached the city, it was held in tanks. The tanks were then tapped to 1200 public fountains, eleven large-scale public baths, 867 smaller baths, and two artificial lakes. The aqueducts of Rome created the original public works system. Water was regulated and taxed to private and public homes. The 38 million gallons of water that went through Rome everyday had to go somewhere, so a sewer system was created to get rid of the excess waste. The sewer in some places was large enough for a good-sized boat to travel through. The excess water from the aqueducts ran through the sewer and into the Tiber River, completing the public works cycle. (Hamblin).
Civil Engineering has been greatly influenced by the Romans. Their civilization was the first to recognize what could be done with water, and they utilized their knowledge to create aqueducts to transport that water. Their engineering feats are still remarkable today, as many bridges and aqueducts are still standing utilizing the arch and cement. Many of their ideas are still put to use today. Aqueducts are still used to transport water, even though Californias extensive aqueduct system which yields 3 billion gallons of water per day, the Romans accomplished their system 2000 years before a comparable system was created (Crystal). The arch was also a brilliant design as it was used as the main structure for bridges until the 17th century. Even today the arch is still a reliable source for bridge building. The Romans were ahead of their time with their brilliant aqueducts.