The San Telmo aqueduct is an engineering work declared an Asset of Cultural Interest as a historical site. It is considered one of the most important hydraulic engineering works of the 18th century in Spain. It carried water from the Guadalmedina to the city through its 10.8 kilometres of length, with 33 bridges, 30 aqueducts and several coffers. It was designed by the architect Martín de Aldehuela, and its construction was carried out between October 1782 and September 1784.
The promoter of the project was José de Molina Lario y Navarro, bishop of the diocese of Málaga. The reasons for the work were the large and growing population of Malaga and the commercial boom that the city was experiencing. Carlos III, through the mediation of the Count of Floridablanca.
The Arroyo Quintana aqueduct is the longest of all the aqueducts, with a length of 170 metres, 15 metres high and 13 spans with semicircular arches. The restoration work was completed in December 2009.
The current owner of the aqueduct is the Caudal y Acueducto de San Telmo Charitable Foundation, presided over by the bishop.
In the prosperous and demographically expanding Malaga of the last quarter of the 18th century, the historical problem of water supply grew more acute after a period of drought. To solve this problem, the then bishop of the city, the learned Don José Molina Lario y Navarro, financed and promoted the construction of an aqueduct that took water from the River Guadalmedina and brought it to the town over a distance of almost 11 kilometres, through which it also provided the element for agricultural irrigation and motive power in the mills. The patron saint of navigators, San Telmo, lends one of the names by which the engineering work in question is known, because the economic benefits generated by the aqueduct were applied to the maintenance of the Nautical College, another interesting enlightened creation of Bishop Molina Lario.
A Royal Order by Charles III in 1782 authorised its construction and on 7 September 1784 the water reached the main ark located in Calle Refino in Malaga. The architect José Martín de Aldehuela was in charge of the design and direction of the construction, and his work was not only practical and of great technical interest, but also charged with aesthetic intent, evident in the nobility of the pure forms, the use of different construction materials and the application of coloured plaster.
The area around the Aqueduct in the Ciudad Jardín neighbourhood has recently been enhanced to improve the space and recover it for public use.
The route of the aqueduct can be divided into two parts, one rural, from the water catchment to the San José estate, still in use, and the other urban, from this estate to the main ark in Calle Refino, a section which is in disuse and in a poor state of conservation. It runs through 33 culverts, 2 tunnels, numerous culverts, breathing holes, landings, fountains and associated mills and 30 bridges. Among them are several of its most monumental landmarks of great scenic value, such as the bridge that spans the Humaina stream, seventy-five metres long and fifteen metres high, or the bridge over the Quintana stream, the longest of them all. It has different sections along its length: square, sixty centimetres on each side, rectangular, forty-two centimetres wide and twenty-eight centimetres high, and two circular sections, one twenty-eight centimetres in diameter and the other twenty centimetres.