Historische Wasserleitungen. Gestern - Heute - Morgen,

Abstract

In 1487, King John the second, ordered the building of an aqueduct to supply with water the town of Setúbal, an harbour on the Atlantic, about 30 kms sout-east of Lisbon. It was the first great aqueduct built in Portugal since the Roman era, at the same time the country was starting the adventure of overseas discoveries. Included on a Franco-Portuguese investigation programme, researchers of the Universities of Évora and Paris 1 Pathéon-Sorbonne realized, on last years, archaeological and architectonic studies on this aqueduct. The aqueduct is approximately 3 kms long. The water comes from the hills northwest of the town where a gallery penetrates into the limestone through a karstic system. Partly in masonry and partly serpentine in the natural hollows, ventilated through wells, the gallery comes out of the earth and takes the shape of an aqueduct built on a wall, slopping, sometimes strongly, towards Setúbal. The course of the aqueduct runs on a pre existing landscape. It runs firstly through the countryside, and follows paths and ways through the tops of walls belonging to farms or quintas. Although well preserved on the countryside, the aqueduct was strongly damaged by the town developments towards north. Nevertheless, there are still remains enough that make possible to understand its original course. At the entrance of the historical centre of Setúbal the aqueduct stands over arcades. In the centre, canals and pipings directed the water towards fountains, some of them of a good architectural and artistic level. The written documentation shows how difficult the water supply was particularly regarding the short debit. According to the explanations, this was due in great part to the geology. Nowadays the source in the bottom of the gallery is dry, a phenomenon not surprising in a karstic environment. But the limestone had also another important inconvenience. Part of the tumble-down wall supporting the aqueduct showed a succession of superposed pipes completely blocked due to calcareous spath (calcite). These inconveniences explain the successive maintenance and repairing works between the 16th and the 19th centuries. Setúbal is a precocious but significant case of the efforts made in countries with hot and dry summers in order to have water all the year through, in the end of Middle Age. Finnaly, as certain sections of the aqueduct are interesting in terms of tourist and pedagogic use, a model and main guidelines to a valorization program is presented.