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Lisbon's Aqueduct

Updated: 20 hours ago

It was built by King João V in the 18th century using the ruins of a Roman aqueduct dating from the 3rd century, known as the Roman Aqueduct of Olisipo, which began at the Roman dam of Belas, about 10 kilometres from Lisbon. The existence of this dam and the Roman aqueduct in the Carenque valley was used as an argument by the defenders of the construction of the Águas Livres Aqueduct, which followed a similar route to the old Roman aqueduct. This construction survived the 1755 earthquake unscathed.

Aqueduto de Lisboa


Ever since people started settling in the Lisbon region, there was a constant shortage of drinking water. Despite the existence of a river in the area, the Tagus, and several streams from Sintra and Oeiras that connected to it, its water was unsuitable for consumption, as the wide mouth of the river causes the water to be contaminated by the sea and therefore has inadequate salinity levels.

The only area of Lisbon with water sources was the Alfama neighbourhood. As the city grew outside the medieval fences, a chronic water supply shortage began to emerge.

The idea of harnessing the waters of the Carenque stream valley, in the Belas region, gained momentum. These waters were first used by the Romans, who had built a dam and aqueduct there.

In 1571, Francisco de Holanda (1517 - 1585) proposed to King Sebastião (1554 - 1578) a water supply network that would serve the city of Lisbon, a network that had already been started by the Romans. The remains of the Roman aqueduct were still sufficient to have been considered, in 1620, for the passage of the Águas Livres de Lisboa. Years later, during the reign of King João V, a new special tax was created by the king in 1728 for the construction of the aqueduct. This tax was confused with the royal water tax, a tax also levied on meat and wine, which had existed since the time of King Manuel I and had been used for other sanitation works in the country.

A year later, in 1729, three men were appointed to draw up the construction plan for the system, which would include building a monumental section of the aqueduct over the Alcântara valley. These three men were António Canevari, an Italian architect, Colonel Engineer Manuel da Maia and João Frederico Ludovice, a German architect who was also responsible for the Royal Convent of Mafra.

Aqueduto de Lisboa

In 1731, King João V's Royal Charter dictated the start of the project. A year later, Canevari was removed from the management of the project and replaced by Manuel da Maia. He guided the route that the aqueduct was to follow from the source to the city. The system would end in a huge "chalice" from which various pipes would emerge to connect to the many fountains scattered throughout Lisbon. A strong but not magnificent aqueduct was chosen, but a monumental castle was built inside the city where the water would arrive, a building that the population could better appreciate due to its proximity.

The work was directed by the Hungarian Carlos Mardel, who, after the great earthquake of 1755, would play a crucial role in the reconstruction of Baixa Pombalina. It was he who decided to install the Mãe d'Água near Rato, in Amoreiras, instead of the initial proposal to locate it in S. Pedro de Alcântara. The solution was much questioned and criticised, especially by Ludovice, who wanted the "chalice" to be built where it had originally been planned, but the work continued nonetheless.

Aqueduto de Lisboa

In 1748 the aqueduct was completed, transporting around 1,300 cubic metres of water a day, three times more than the original supply. With a total of 127 arches, the best known and most visible section of the Águas Livres aqueduct is the one that passes over the Alcântara valley. It is 941 metres long and consists of 21 round arches and 14 central ogival arches. Of all the fourteen ogival arches, the Arco Grande stands out. The largest arch of the imposing arcade was the most difficult part of this section, and perhaps of the whole construction. It measures 65 metres in height and is 29 metres apart, making it the largest ogival arch in the world. It had to be designed this way because of the passage of the Alcântara stream between its piers.

Period of Operation

After it began operating in 1748, a whole new network of gravity-fed fountains and springs was built in the city, such as the Chafariz da Esperança. The aqueduct's capacity was also increased from the outset due to the growing need for water fuelled by the city's demographic growth. The successive extensions of the aqueduct, mainly upstream, with the aim of bringing more water to it, totalled a length of 58,135 metres of underground and elevated galleries.

The public road above the aqueduct has been closed since 1837, partly due to the crimes committed by Diogo Alves (the Pancadas), a criminal who threw his victims from the top of the arches after robbing them, simulating a suicide, but was caught by the authorities and sentenced to hang. He was the last man sentenced to death in Portuguese history.

In 1880, the importance of the aqueduct was greatly diminished by the start of the exploitation of the waters of the Alviela through the Alviela Aqueduct, which took the water to the Barbadinhos reservoir where it was raised by steam engines, supplying Lisbon with drinking water. However, the aqueduct remained in operation until 1967, when metal pipes were laid to carry water from other sources (the concrete footings where they were laid are still visible inside), and was definitively decommissioned by the Companhia das Águas de Lisboa in 1968.

Other curiosities

EPAL has resumed circulation in the Águas Livres Aqueduct as of 2023, five decades after it was completely deactivated due to the decrease in flows from the springs. The circuit can be useful during fires, irrigation and disasters such as earthquakes. The company will install 200 drinking fountains in Lisbon, with structures so that the water can also be consumed by pets, as well as restoring Lisbon's fountains and supplying water to the lake in the Príncipe Real Garden.

Source: EPAL

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