Aqueduct
Aqueduct (from the Latin, aquaeductus, which transports water) is an irrigation system or set of systems that allows water to be transported in a continuous flow from a a place where it is accessible in nature to a distant point of consumption, usually a city or town. In modern engineering, the term aqueduct is used for any system of pipes, ditches, canals, tunnels, and other structures used for this purpose.. The term aqueduct also often refers specifically to a bridge that people cross for added safety. Aqueducts were used in ancient Greece, ancient Egypt, and ancient Rome, even in ancient Mexico. In modern times, the largest aqueducts of all have been built in the United States to supply large cities. The simplest aqueducts are small trenches dug into the ground. Much larger channels can be used in modern aqueducts. Aqueducts sometimes run part or all of their way through tunnels built underground. Modern aqueducts can also use pipes. Historically, agricultural societies have built aqueducts to irrigate crops and supply large towns with drinking water.
Etymology
The word aqueduct comes from the Latin aquaeductus, formed by aqua, (water) and duct. Duct comes from the verb ducere (to guide).
History
Any human settlement, no matter how small, needs to have a water supply system that meets their vital needs. The solution used since ancient times consisted of establishing the settlement in the vicinity of a river or spring, from where the water is carried to the points of consumption. Another solution is to dig wells inside or outside the inhabited area or build cisterns. But when the settlement reaches the category of a true city, conduction systems are necessary that obtain water in the most suitable points of the environment and take it to the place where the population has been established.
Even when the population was on the banks of a river, the construction of pipes was the best way to guarantee the supply, instead of extracting the water from the river that, even if it was very close, generally had a lower level than the populated. On other occasions the aqueduct was built because the water was of better quality than that of the river. To cover this need, large-scale works are undertaken that can ensure a water supply.
Although there were precedents in the ancient civilizations of the Near East and the Greek engineers had built efficient pipelines, the Roman engineers, thanks mainly to their use of concrete, were the ones who developed techniques that could be generalized throughout the cities of the world. Mediterranean. However, technical factors were not the only ones that contributed to the spread of this type of works, it also required the political unity of the Empire and the existence of a strong economic system that created the conditions for urban development.
Most of the route was made through canals, generally covered, which were built along the slopes of the mountains, following the desired slope line (generally small, around 0.004%), and were located from time to time water boxes or water chests, small tanks that were used to regulate the flow or decant the solids, usually sand, that the waters could carry away.
When a path had to be saved, at a level a little lower than that of the aqueduct, siphons were used, in which the water passed under the obstacle and rose again to the previous level. They often had to overcome larger differences in level and in them they took the form of an arch or bridge, since making siphon pipes capable of withstanding high pressures was more expensive. As the bridges are the most visible part of the work, the custom of calling the arches themselves an "aqueduct" has remained.
On many occasions, these Roman aqueducts continued in use throughout the Middle Ages and even into modern times, thanks to repairs and restorations. And, of course, new ones continued to be made.
The solutions applied to Roman aqueducts continued to be used without substantial modifications until the 19th century. In the XX century, progress in cement production, reinforcing concrete with steel, new materials and techniques in the construction of conduits and the possibility of building powerful pumping stations revolutionized water pipes and simplified their adaptation to the terrain.
Ancient aqueducts
Though associated particularly with the Romans, aqueducts were devised much earlier in Greece, the Near East, and the Indian subcontinent, where peoples like the Egyptians and the Harappans built sophisticated irrigation systems. The Romans built the largest and most important aqueducts in all their territories. Roman-style aqueducts were in use as early as the 17th century VII a. BC, when the Assyrians built an 80 km long limestone aqueduct, including a 10 m high section to cross a 300 m wide valley, to bring water to their capital city Nineveh.
Indian
The Indian subcontinent is believed to have some of the earliest aqueducts. Evidence can be found at the sites of present-day Hampi. The huge aqueducts near the Tungabhadra river that supply irrigation water were once 15 km long. The canals supplied water to the royal baths.
Petra, Jordan
Throughout Petra, Jordan, Nabataean engineers harnessed every natural spring and winter downpour to channel water to where it was needed. They built aqueducts and pipe systems that allowed water to flow over the mountains, through gorges, and into the temples, homes, and gardens of the citizens of Petra. Walking through the Siq, you can easily see the remains of the canals that directed water to the center of the city, as well as reinforced dams that kept floodwaters at bay in periods of flooding.
Greece
On the island of Samos, the Eupalinos Tunnel was built during the reign of Polycrates (538-522 BC). It is considered an underground aqueduct and brought fresh water to the Pythagoreans for about a thousand years.
Rome
Roman aqueducts were built throughout the Roman Empire, from Germany to Africa, and especially in the city of Rome, where they totaled more than 415km long. In the great cities of the empire, aqueducts supplied fresh water for public baths and drinking and set an engineering standard that was not surpassed for over a thousand years. Bridges, built of stone with multiple arches, were a distinctive feature of Roman aqueducts, and thus the term "aqueduct" often applied specifically to a bridge for carrying water.
South America
Near the Peruvian city of Nazca, an ancient pre-Columbian aqueduct system called Puquios was built and is still in use today. They were made of intricately placed stones, a building material widely used by the Nazca culture. The time period in which they were built is still debated, but some evidence supports around AD 540–552. C., in response to periods of drought in the region.
North America
Costa Rica's Guayabo National Monument, a park that covers the country's largest archaeological site, contains a system of aqueducts. The complex network of uncovered and covered aqueducts still works well. The aqueducts are constructed of rounded river stones, which are mostly of volcanic origin. The civilization that built the aqueduct system remains a mystery to archaeologists; It is suspected that the Guayabo aqueducts were located at a point of ancient cultural confluence between the Aztecs, Mayans and Incas.
When Europeans arrived in the Aztec capital Tenochtitlán in the early 16th century century, the city was connected by two aqueducts. One of these, the Chapultepec Aqueduct, built around 1420, was rebuilt by the Spanish almost three hundred years later. Originally tracing part of its path over the now disappeared Lake Texcoco, of which, currently, only a fragment remains in Mexico City.
Sri Lankan
Extensive use of elaborate aqueducts has been discovered in ancient Sri Lanka. The best example is the Yoda Ela or Jaya Ganga, an 87km long water channel that carries excess water between two artificial reservoirs with a gradient of 10 to 20 cm per kilometer over the century V d. However, the old engineering methods of calculating the exact elevation between the two reservoirs and the exact gradient of the channel with such fine precision had been lost with the fall of civilization in the XIII.
Design
An aqueduct starts in a water collection system. The water passes in a controlled manner to the pipe from a header tank (caput aquae), also known as castellum, from where it was distributed throughout the city.
The construction of an aqueduct requires a detailed study of the land that will allow choosing the most economical route to allow a gentle and sustained slope without lengthening the route of the work too much.
Canals (riui) are used without pressure (circulating in a free layer) whenever possible and only on rare occasions is pressure conduction used.
In any case, whenever the water is used for human consumption, the canal is covered by vaults, false vaults, stone plates or tégulas.
The canal is accommodated to the ground by different procedures. Whenever possible, it takes place on the ground supported by a wall (substructio) in which culverts are made to facilitate the normal transit of surface water. If the ground rises, the channel is buried (riuus subterraneus) and forms an underground gallery (specus) dug directly into the rock or built into a trench. When a strong depression has to be overcome, they resort to the construction of complicated archery systems (arcuationes) that support the canal and keep it at the proper level.
If a mountain that cannot be surrounded gets in the way of the pipeline route, a tunnel is built that perforates it. This procedure is only used if it is unavoidable. Tunnels pose major technical problems. Normally they start at both ends, which requires great precision in the work so that the two branches meet at the expected point. The narrowness of the cutting areas requires that only one or two men work on each pit, so the work progresses very slowly.
Underground pipelines are usually connected to the surface by means of (putei) wells arranged at regular intervals. Through them you can access the aqueduct for cleaning and maintenance. In the case of the tunnels, they also served to remove rubble and introduce materials during construction, as well as to ensure the correct layout and depth of the excavation.
The channels, unless they were directly excavated in impermeable rock, were lined with an impermeable mortar composed of lime and small fragments of crushed ceramic (opus signinum). The interior angles were protected with a convex molding (half round) of the same material.
Although Roman technicians also used pipes under pressure through lead (fistulae) or ceramic (tubuli fictiles) tubes, they only rarely did so, since the deficient technology available for the construction of tubes made them expensive and unsafe. The ceramic ones were cheap and easy to manufacture on site, but they were too brittle. Those made of lead, apart from the cost of the material, required a very laborious transport, given their weight.
There were also rudimentary stone pipes, made up of large perforated ashlars that were assembled together thanks to a tongue-and-groove joint that was sealed with lime mortar. This procedure was used to transport water through flat areas where it was impossible to maintain an adequate slope for conduction through a free channel. Sometimes wooden tubes and channels appear to have been used as well.
Syphons were used to overcome not very pronounced depressions, difficult to overcome by other systems. The water carried by the aqueduct channel was collected in a header tank from which it came out under pressure through the tubes of the descending branch, which sought the bottom of the depression. After it began the ascending branch that, once the depression was overcome, poured the water into an outlet tank, from which the water came out again through a channel in a free sheet. The angles formed by the tubes were ballasted with thick stones to avoid breaking the joints due to the pressure that the water exerted on them. When the difference in level to be saved was significant, the water pressure could burst the pipe, so it was more economical to save the ravine by means of an arch.
In some cases, the arches of an aqueduct were used to also build a road bridge, as in the case of the Pont du Gard (which is why it is known as a bridge, pont).).
In different points of the pipes, devices were inserted whose purpose was to dam the water current to allow the solid drags to settle, water boxes or water chests. They all have in common that they are made up of intermediate receptacles with the bottom at a lower level than that of the water inlet and outlet channels. The trawls precipitate and fall to the bottom, from where they could be extracted periodically. The simplest type is a simple well made in the bottom of the channel. The largest specimens are small stone deposits (piscinae limariae) covered with opus signinum.
When the pipeline reaches the city walls, its flow is collected in a terminal cistern, which serves to regulate the supply. From it, water is supplied to citizens by a distribution system.
According to Frontinus, the Romans were satisfied for a long time with the water they extracted from the Tiber, from wells and springs. Things were like this for the first 441 years since the founding of the city. Its first aqueduct was underground, the Aqua Apia, which stretched about 16 km, built at the initiative of the censor Appius Claudius the Censor in the year 312 BC. Later, they built the first one that carried water on the surface, the Aqua Marcia, in Rome, which covered about 90 km (144 BC). In the time of Frontinus, who wrote his treatise on the aqueducts of Rome in 97 or shortly after, most of its route was underground, but when it arrived near the city there was a short section that ran on the surface on a wall and arches.
The Old Anion Conduction, built in 273 B.C. C., although it travels on the surface for a not very long stretch, it lacks arches, according to Frontino's description. All the other pipes in Rome have important sections of arcades, which, in general, are longer the more modern they are. The aqueduct that fed Carthage, in present-day Tunisia, from the II century, ran a distance of 132 km from Zaguán, from the which 17 km were in archery.
It is, therefore, a fact that the oldest aqueducts in the city tend to prefer underground conduction whenever possible. It is also known from Frontino that on occasions, with the passage of time, the detours required by the underground route were replaced in some of the pipes by shorter routes over arches. The preference for underground routes in the oldest aqueducts is due, more than to technical limitations, to the interest in protecting pipes from sabotage in times of war or to the old Roman experience in the construction of drains and sewers.
But it is no less true that in the two mentioned aqueducts the main conduction systems used in all times are added: underground conduction, in tunnel, on wall and on arches. As if this were not enough, the layout of the Anion Viejo aqueduct includes a siphon, which quite completes the repertoire of technical solutions. Vitruvius, writing his De architectura libri decem probably shortly before 27 B.C. C., already mentions all the conduction systems mentioned in this article, with the exception of stone pipes, which do not appear in any treatise, and wooden tubes and channels, which must be of very late use. In fact, Faventino, who practically follows Vitruvio in everything, is the only theoretician who mentions them, thus departing from his source. And keep in mind that he most likely wrote his work at the end of the IV century.
Therefore, one must think that all the technical resources available to the Romans to conduct water were at their fingertips from the very beginning.
The aqueducts that were built from the XIX century, were far from the beautiful Roman works, many of which they are still in operation today, like those that supply water to the fountains of Rome.
Modern aqueducts are generally built underground, as extensive networks of iron, steel or concrete pipes. The Delaware aqueduct, which transports water from the Catskill Mountains to New York, has a length of 137 km and is the second continuous transport aqueduct, to supply populations with greater length (although it is only 5 kilometers more). than the Roman that fed Carthage).
The longest aqueduct in the world is called Acueducto Vizcaíno-Pacífico Norte in the municipality of Mulegé, Baja California Sur, Mexico. Said work has a length of 315 kilometers and leads to an expense of 60 liters per second of water.
Aqueduct-bridges in the Iberian Peninsula
- Prata Aqueduct in Evora. The centuryXVI.
- Aqueduct of Algeciras or the arches of El Cobre, on the outskirts of Algeciras, province of Cadiz. The centuryXVIII.
- Aqueduct of Almuñécar, in the province of Granada, of Roman times.
- Aqueducto de Bejís, province of Castellón. The centuryXVI.
- Plasencia aqueduct or arches of San Antón, province of Cáceres.
- Aqueduct of Los Arcos, in Calanda, province of Teruel. The centuryXVII.
- Aqueduct of the Pillars in Oviedo, principal of Asturias. The centuryXVI.
- Aqueduct of the Free Waters in Lisbon. The centuryXVIII.
- Aqueduct of the Miracles in Merida, province of Badajoz. Roman times.
- Aqueducto de Morella, province of Castellón. The centuryXIV.
- Aqueducto de Peña Cortada to the outskirts of Chelva, province of Valencia. Roman times.
- San Lazaro aqueduct in Merida. The centuryXVI built with elements of an adjacent Roman aqueduct of which there are still three archery close to the Roman circus.
- San Telmo aqueduct outside Malaga. The centuryXVIII.
- Segovia aqueduct. Roman times.
- Aqueduct of the Eagle to the outskirts of Nerja, province of Malaga. The centuryXIX.
- Aqueducto Los Arcos de Alpuente, province of Valencia. The centuryXVI.
- Aqueducto Los Arcos (Teruel). The centuryXVI.
- Caños de Carmona in Seville. Roman origin, reformed by almohades and in the centuryXIV.
- Devil Bridge or Les Ferreres aqueduct, just outside Tarragona. Roman times.
- Aqueducto de Valencia de Alcántara province of Cáceres.
In the south of France, the following stand out:
- Arles aqueduct outside Fontvielle, near Arles. Roman times.
- San Clemente aqueduct in the city of Montpellier. The centuryXVII.
- Gard Bridge just outside Nimes. Roman times.
Aqueducts around the world
Rome
Aqueducts of Rome
Chile
Loncomilla Siphon Bridge
Columbia
Bogota Aqueduct
Mexico
- Aqueduct of Santiago de Querétaro: built between 1726 and 1738, has an average height of 23 m and a length of 1300 m, consisting of 74 arches.
- El Saucillo aqueduct: built between 1732 and 1736, with a height in its central arches of 44 meters.
- Aqueduct of Father Tembleque, 45 kilometers long.
- Chapultepec aqueduct: the oldest in Mexico.
- Tepotzotlán aqueduct: also known as "Arcos del Sitio", built by Jesuits in the centuryXVIII, stand out its 4 levels of arches.
- Remedies aqueduct.
- Morelia aqueduct.
- Aqueduct of Zacatecas: known colloquially as "Aqueduct of the cube".
- Chihuahua aqueduct: 5 kilometers long.
- Guadalupe aqueduct: located in the north of Mexico City, 7 kilometers long.
- Acámbaro aqueduct, Guanajuato.
- San Felipe del Agua aqueduct of Oaxaca.
- Nochistlán aqueduct.
- Aqueducto Vizcaíno-Pacifico Norte.
Simulation software
Currently, most aqueduct systems are simulated through computer models, which vary widely in complexity, licensing, cost, among other variables. Some of the available tools are listed below, classified by the type of licensing they have.
Free to use software
- Epanet: widely used by engineers worldwide, is produced by the United States EPA.
Software for commercial use
- WaterCAD: produced by Haestad Methods (today Bentley) has a high cost for the average user, but offers a wide range of operating options.
- H2ONet