The “qanats” of the Los Alcores aquifer and the traditional water supply system to Seville

Abstract

Due to the quality and the topographic position of its waters, the Los Alcores aquifer has been the main supply of running and drinking water for the city of Seville for many centuries. In the first century, a complex water supply system, of more than 17 km in length, was built to withdraw groundwaters in the southern part of the aquifer and whose main elements were an extensive network of “qanats”, a surface conduction and a reservoir in the city (castellum aquae). After the abandonment of this infrastructure, the surface conduction was reconstructed in the 12th century (known as Caños de Carmona), which was made up of a canal and, in the part closest to the city, by a brick aqueduct over arches. Since the end of the 19th century, the urban, industrial and the transport network development and the conduction of water from the reservoirs of the Sierra Morena produced, once again, the progressive abandonment and destruction of these infrastructures. However, a large part of the “qanat” network excavated in the Los Alcores aquifer has been preserved and recently the GEOS and AAES speleological groups have explored about 20 km of water mines. The characteristics of tunnels and vertical shafts, the construction techniques, the discovery of Roman mortar (opus signinum) and bricks (opus testaceum) and the Arab chronicles suggest that this network of “qanats” was made mainly during the Roman domination period.