The Tunnels of Claudius () consist principally of a 6 km-long tunnel (or ''emissary'') together with several monumental service tunnels which

Roman Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of Roman civilization *Epistle to the Romans, shortened to Romans, a letter w ...

Emperor

Claudius Tiberius Claudius Caesar Augustus Germanicus ( ; ; 1 August 10 BC – 13 October AD 54), or Claudius, was a Roman emperor, ruling from AD 41 to 54. A member of the Julio-Claudian dynasty, Claudius was born to Nero Claudius Drusus, Drusus and Ant ...

had built by 52 AD to partially drain the

Fucine Lake The Fucine Lake ( or ) was a large endorheic karst lake between above sea level and surrounded by the Monte Sirente- Monte Velino mountain ranges to the north-northeast, Mount Salviano to the west, Vallelonga to the south, and the Valle del G ...

Abruzzo Abruzzo (, ; ; , ''Abbrìzze'' or ''Abbrèzze'' ; ), historically also known as Abruzzi, is a Regions of Italy, region of Southern Italy with an area of 10,763 square km (4,156 sq mi) and a population of 1.3 million. It is divided into four ...

, protecting riparian villages from floods and creating agricultural land. It was a massive engineering project involving 30,000 workmen and slaves who completed it in just 11 years, and considered among the grandest in antiquity. It was the longest tunnel ever built until the inauguration of the

Fréjus Rail Tunnel The Fréjus Rail Tunnel (also called Mont Cenis Tunnel) is a rail tunnel of length in the European Alps, carrying the Turin–Modane railway through Mont Cenis to an end-on connection with the Culoz–Modane railway and linking Bardonecc ...

in 1871. The lake water flowed under Mount Salviano and emptied into the Liri River beneath the present town of Capistrello. Without regular maintenance the emissary often became clogged, and the lake returned to its original size with regular flooding. It was only in 1854 when

Alessandro Torlonia Prince ''Don (honorific), Don'' Alessandro Raffaele Torlonia, Prince of Fucino, Princes of Civitella-Cesi, Prince of Civitella-Cesi, Duke of Ceri (January 1, 1800 – February 7, 1886) was an Italian nobleman of the House of Torlonia. He was the ...

renovated the tunnels mostly following the Roman ones that knowledge of the Roman tunnel was increased whilst also causing the destruction of its superficial features. Original Roman features can be seen in ''

opus reticulatum ''Opus reticulatum'' (also known as reticulate work) is a facing used for concrete walls in Ancient Roman architecture, Roman architecture from about the first century BCE to the early first century CE. Facings are a type of polygonal masonry us ...

'' in the entrance and exit areas. In 1902 the "Tunnels of Claudius" (including the many service tunnels) were included among Italian national monuments; the tunnel area represents a site of archaeological and speleological interest, provided with a park inaugurated in 1977 with the purpose of protecting and exploiting the whole system..

History

Lake Fucino was once the 3rd largest lake in Italy and the area is a basin completely enclosed by mountains and with no natural outlet. It is fed by snow meltwater and the seasonal ancient water level variation is estimated to be typically 12 m.

Planning

The

Marsi The Marsi were an Italic people of ancient Italy, whose chief centre was Marruvium, on the eastern shore of Lake Fucinus (which was drained in the time of Claudius). The area in which they lived is now called Marsica. They originally spoke a l ...

, the local inhabitants, had made petitions to Rome to control the unstable level of the lake which very often flooded villages because of the frequent cloggings of the only natural swallow-hole at Petogna near Luco dei Marsi. In summer because of the receding waters, the lands surrounding the inhabited areas often became marshy causing serious health problems due to

malaria Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...

. The first plan to drain the lake was of

Julius Caesar Gaius Julius Caesar (12 or 13 July 100 BC – 15 March 44 BC) was a Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey in Caesar's civil wa ...

(r. 49-44 BC) but he died before it could be advanced. In 41 AD Emperor

resumed the ambitious plan and, thanks to substantial public financing, entrusted a Roman enterprise with the works. The easiest plan was to dig the shortest tunnel through the low Cesolino hill and into the Salto River and eventually into the

Tiber The Tiber ( ; ; ) is the List of rivers of Italy, third-longest river in Italy and the longest in Central Italy, rising in the Apennine Mountains in Emilia-Romagna and flowing through Tuscany, Umbria, and Lazio, where it is joined by the R ...

. This was discarded because it would be a flood threat to

Rome Rome (Italian language, Italian and , ) is the capital city and most populated (municipality) of Italy. It is also the administrative centre of the Lazio Regions of Italy, region and of the Metropolitan City of Rome. A special named with 2, ...

. The second, more difficult, plan was therefore adopted with a longer, deeper tunnel to lead the water into the Liri River The aim was to only regulate the water level and not drain the lake completely. The tunnel had to be designed to be the shortest compatible with a very shallow slope and in a compass direction that ensured it entered the Liri river at a level lower than the lake, a remarkable feat considering the instruments of the time. Once the direction was decided, the required inclination then determined the location of the tunnel ends. The emissary has a variable cross-section of , an average flow rate of and an average gradient of .

Construction

The system consisted of three main parts: * The ''incile'': the canal for collecting the water in a set of tanks and dam * The main tunnel * The ''cunicola'': the secondary service tunnels and ''wells''. The system of vertical wells with a square section and the inclined tunnels increased the number of places where the main tunnel could be excavated to speed up construction. They also provided air and ventilation as well as allowing removal of waste and water during construction. Where the rock was weak the tunnels had to be supported with scaffolding and remains of this was found in Torlonia's renovation. Once a well was dug to the appropriate depth, tunnel excavation started proceeding in opposite directions. At least 40 wells were dug, 29 of which are on the west side of the mount Salviano and 11 on the east slope. The depth of the wells varies from 19 m to 122 m (number 22) while those on the western side are generally greater than 80 m. The depth of the wells was determined through the use of a surveying technique known as ''cultellatio'' consisting of mapping and finding the level of the land in places along the route by means of a series of horizontal and vertical steps. The sum of the vertical and horizontal measurements made possible the calculation of levels and distances. A vertical well was then dug to a required depth relative to the water intake. Subsequently, other vertical wells were dug along the route using the same technique. The long section under Mount Salviano where wells could not be dug was the most difficult and went through loose rock and pebbles making a deviation necessary. Accidents during the construction included several landslides in the most vulnerable and sandiest sections and in the dam between the mouth of the tunnel near the Fucine inlet.

Completion

When the works were concluded Claudius, before the opening of the locks, celebrated the work by organising a great

naumachia A naumachia (in Latin , from the Ancient Greek /, literally "naval combat") was a mock naval battle staged as mass entertainment by the Ancient Romans. The staging would typically occur in a specially-dug basin, also known as a naumachia. Earl ...

, a naval battle with warships on the lake with 19000 combatants made up of gladiators and criminals, with the presence of his wife Agrippina and the young

Nero Nero Claudius Caesar Augustus Germanicus ( ; born Lucius Domitius Ahenobarbus; 15 December AD 37 – 9 June AD 68) was a Roman emperor and the final emperor of the Julio-Claudian dynasty, reigning from AD 54 until his ...

. Crowds of spectators came from all over Italy to see the show. It was soon discovered that the emissary was not deep enough so the outlet was dammed and the tunnel excavated further. On completion Claudius held a second gladiatorial battle on the lake on a huge stage of pontoons. The lake shrank by about and warded off the flood danger. The economy of Marsica and especially of the cities of

Alba Fucens Alba Fucens was an ancient Italic people, Italic town located at elevation at the base of Monte Velino, approximately north of Avezzano, Abruzzo, central Italy. Its ruins can be found in the ''comune'' of Massa d'Albe. The city is largely vis ...

, Lucus Angitiae and

Marruvium San Benedetto dei Marsi (, ; ) is a ''comune ''and town in the province of L'Aquila in the Abruzzo region of central Italy. It is on the eastern shore of the dried Lake Fucino, from the remains of another ancient site, Alba Fucens. Near the town ...

thrived and the surrounding mountainous areas became popular as holiday resorts. Later under

Trajan Trajan ( ; born Marcus Ulpius Traianus, 18 September 53) was a Roman emperor from AD 98 to 117, remembered as the second of the Five Good Emperors of the Nerva–Antonine dynasty. He was a philanthropic ruler and a successful soldier ...

, between 98 and 117 AD, and

Hadrian Hadrian ( ; ; 24 January 76 – 10 July 138) was Roman emperor from 117 to 138. Hadrian was born in Italica, close to modern Seville in Spain, an Italic peoples, Italic settlement in Hispania Baetica; his branch of the Aelia gens, Aelia '' ...

, between 117 and 138 AD clearance of blockages and repairs became necessary.

Neglect

The tunnel was soon neglected by

(r.54-68) and became blocked, but was re-opened by Hadrian. It was blocked again before 235. With the

fall of the Roman Empire The fall of the Western Roman Empire, also called the fall of the Roman Empire or the fall of Rome, was the loss of central political control in the Western Roman Empire, a process in which the Empire failed to enforce its rule, and its vast ...

and the

Barbarian invasions The Migration Period ( 300 to 600 AD), also known as the Barbarian Invasions, was a period in European history marked by large-scale migrations that saw the fall of the Western Roman Empire and subsequent settlement of its former territories ...

maintenance inevitably failed and also because of a serious earthquake in 508 AD, the canal was clogged with the consequent return of the Fucine Lake to its previous levels. In the subsequent centuries Frederick II of Hohenstaufen (13th century) and

Ferdinand I of the Two Sicilies Ferdinand I (Italian language, Italian: ''Ferdinando I''; 12 January 1751 – 4 January 1825) was Kingdom of the Two Sicilies, King of the Two Sicilies from 1816 until his death. Before that he had been, since 1759, King of Naples as Ferdinand I ...

(1790) tried to restore the water drainage into the Roman emissary, failing due to the scarcity of funds and the complexity of the project. In 1854 Torlonia finally renovated the tunnel mostly following that of Claudius. Imbocco Emissario di Claudio

Recent Restoration

In June 1977, with the aim of protecting and exploiting the work, the Archaeological Park of Claudius was established, between the entrances to the tunnels and the Fucine Inlet. The work was included among the ''Luoghi del Cuore'' ("Places of the Heart") for the year 2016 by FAI.

The tunnels

The most impressive service tunnels were on the eastern side: * Major Tunnel (), located on the eastern side of the mountain, is the most monumental and features three large arches for entrances which join together after a short inner stretch. It gave access to the deepest section under the mountain. Inside is the oblique tunnel (the so-called bypass). * Blacksmith Tunnel (), on the eastern side of the mountain. The first stretch was paved and equipped with lighting. The bypass connects it with the Major tunnel. * Imperial Tunnel (), located lower than the previous one, connected to it through well no. 23. * Coppersmith, Machine and Oil-Lamp Tunnels (), on the western side of the mountain.

References

Bibliography

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External links

* {{cite web, url=http://www.regione.abruzzo.it/xCultura/index.asp?modello=sitoarcaq&servizio=xList&stileDiv=monoLeft&template=intIndex&b=menuSiti264&tom=64, title=Cunicoli di Claudio, website=regione.abruzzo.it, publisher=Regione Abruzzo, access-date=10 June 2017, language=it, archive-date=21 February 2018, archive-url=https://web.archive.org/web/20180221222421/http://www.regione.abruzzo.it/xCultura/index.asp?modello=sitoarcaq&servizio=xList&stileDiv=monoLeft&template=intIndex&b=menuSiti264&tom=64, url-status=dead Roman aqueducts Roman sites of Abruzzo Province of L'Aquila Buildings and structures in Avezzano Claudius House of Torlonia Marsica Capistrello