The Águas Livres Aqueduct, is a baroque architectural infrastructure commissioned by King Dom João V, which was built between 1731 and 1799,. It is a hydraulic structure that stretches over 36 miles, built of cut stone quarried in the Lisbon area, together with limestone masonry.
It was the last great classical aqueduct to be built all over the world, constituting a system for the capture and transport of water, which passes through five separate municipalities in Portugal: Amadora, Lisboa, Odivelas, Oeiras and Sintra. It begins in a rural area, in the municipality of Sintra, where it cohabits with cultivated fields and pine groves, and, throughout its length, it crosses urban areas, surrounded by buildings and public roads. In the municipality of Amadora, it runs parallel to the railway line from Sintra to Lisbon.
On the one hand, the Águas Livres Aqueduct is characterised by its main section, known as the Main Aqueduct, which stretches over a distance of 14.256 km, and by a series of subsidiary aqueducts and head race tunnels that, together with the main section, comprise a total network of roughly 58 km. Over the course of the Águas Livres Aqueduct, the water is transported through the action of gravity (roughly 3mm of water for each metre), sometimes running underground, and at other times breaking out onto the surface. At its extremities, it has three main reservoirs: two catchment areas, in the municipality of Sintra and in the municipality of Amadora, known respectively as the Mãe de Água Velha (Old Reservoir) and the Mãe de Água Nova (New Reservoir), as well as a reservoir in Lisbon, known as the Mãe de Água das Amoreiras (Amoreiras Reservoir).
The Main Aqueduct, which begins at the Mãe de Água Velha, in the municipality of Sintra, and ends in the area of Amoreiras, in the parish of Santo António, in Lisbon, was fed by 58 separate water sources.
The visible stretches of the aqueduct display a structure built of limestone blocks, with rows of regular and even-sized cut stones, designed to support the water conduits, which, in turn, are protected by walls of stone pitching with filled joints, with a round, flat or angular roof, interrupted by vents or skylights, when the structure runs underground. These vents or skylights provide the lighting for the water conduits and head race tunnels, as well as ensuring that they are supplied with oxygen, in order to guarantee the safe quality of the water and to allow for the continued presence there of human beings to clean the gutters and supervise the structure.
In the section of the aqueduct that is visible over the Alcântara valley, in Lisbon, these vents or skylights are more elaborate, displaying erudite architectural elements, such as pilasters and pediments.
The idea of capturing the free waters (Águas Livres) for the aqueduct dates back to the time when there was an insufficient water supply within the city of Lisbon, particularly in the western area, in Bairro Alto, where the problem was further exacerbated by the urban growth that took place in the late sixteenth century. This situation became even worse in the reign of Dom João V. Accordingly, on 12 May, 1731, the King of Portugal ordered the beginning of the Águas Livres Aqueduct construction.
The building of this public work took on special significance for the Municipal Council and for the people of Lisbon, since they were both called upon to bear the brunt of the costs of this work. The tax that the local population had to pay for this purpose, known as the Real D’Água, dates back to 1729, and was levied on staple foodstuffs, such as wine, meat and olive-oil.
The building of the Águas Livres Aqueduct was completed in 1799, and, in 1834, the Mãe d’Água reservoir in Amoreiras was finally ready for use. Besides its being one of the most splendid of the many monuments that the king ordered to be built or had planned for the city, the fact that the Águas Livres Aqueduct did not suffer any major damage with the devastating earthquake that struck Lisbon in 1755 also contributed to the national and international recognition of its solidity and of the technical prowess demonstrated by Portuguese military engineering.
The construction of the Águas Livres Aqueduct was an extremely lengthy process, taking all of the eighteenth century and continuing well into the nineteenth century, with the building of its secondary branches – subsidiary aqueducts, water conduits and head race tunnels – and its fountains, as well as, finally, the completion of the Mãe de Água reservoir in Amoreiras.
The arches of the Alcântara valley, in Lisbon, consist of a row of pointed arches supported by pillars made of blocks of cut stone. This whole section was surmounted by classically inspired lantern-shaped skylights, made from blocks of ashlar masonry, with hipped roofs. The skylights have a pinnacle at their uppermost point and stand upon triangular pediments, with Tuscan pilasters in the corners, wider at the bases and standing on pedestals, surmounted by a frieze and a cornice, displaying a semi-circular arch on each face, standing on prominent imposts and with an equally prominent keystone.
This group of arches differs from those existing on the other stretches of the aqueduct, since these latter structures have a square floor plan, with a hipped roof, and contain four right-angled windows, protected by railings.
Throughout its course, the hydraulic structure has multiple skylights, either plain or afforded an artistic decoration, with attention being drawn to the fact that some of them have a baroque inspiration, with a domed roof, crowned by pinnacles surmounted by a sphere.
Both the Arco das Amoreiras and the Arco de São Bento, two arches located in Lisbon, are characterised by their sober lines, displaying a geometrical composition, in keeping with a neoclassical context, which makes it easy to associate them with the triumphal Roman arches, and, at the same time, they are adorned with baroque decorative elements.
The Águas Livres Aqueduct ends in a reservoir – the Mãe d’Água das Amoreiras – which was not planned to be merely utilitarian in nature, so that, even through its geographical location, it has been afforded an artistic appearance that makes it a grandiose and clearly visible building.
The building housing the reservoir of Mãe d’Água das Amoreiras (in the parish of Santo António, in the municipality of Lisbon) displays mostly sober architectural lines. Attention is drawn to some of its classical features, such as the use of the Tuscan order, and its decorative features, such as the gargoyles in the cornice. All of the building’s façades, when compared with those of the rest of the area in which they are to be found, have very small doors and windows.
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