Resumen de Alimentation et gestion de l’eau sur la colline de Fourvière à Lyon: les aménagements hydrauliques, la ville et ses monuments
- English
On Fourvière hill, which reaches a maximum altitude of about 298 m NGF, the public buildings, thermal baths, fountains, reservoirs as well as the houses and private amenities were supplied with water by the four Lyon aqueducts.
The constraints caused by the topography of the hill on which the Roman colony was established made it difficult to supply the districts located in the highest part of the hill, in particular those located above 270 m. The Saint-Just and Minimes sectors could be supplied by the Mont d’Or and Yzeron aqueducts, which must have arrived at a maximum altitude of around 260 and 268 m NGF respectively. A large part of the upper town, above the theatre district, was only served in the middle of the 1st century AD by the Brévenne aqueduct, which discharged its water at an altitude of between 285.50 and 287.50 m NGF. As for the Gier aqueduct, the remains of the last piers of which confirm that it arrived at around 300 m NGF, it supplied the top of the Sarra and Fourvière plateau from the reign of Hadrian onwards. This situation therefore meant that, over a long period of time, other types of hydraulic works would have been used to exploit the water table, located at a great depth, or rainwater.
Thanks to the new possibilities offered by tools such as the Archaeological Map of Lyon, the Topographic Atlas and the Alyas GIS of the Archaeological Service of the City of Lyon (SAVL), our survey of wells, cisterns, reservoirs as well as fountains and thermal baths aims to provide a synthesis of the different forms of water supply and distribution on the hill in order to understand the relationship between these structures and aqueducts and the urban development of the settlement. Our study shows that the absence of running water from an aqueduct did not prevent the upper districts of the hill being occupied and developed. From the first decades of the ancient city, the large amount of water essential to the private blocks and monuments was supplied by wells and cisterns.
The distribution and chronology of the first category of these facilities paint a clear picture. The wells, both Republican and Augustan, are almost all concentrated in sectors above 280 m NGF. The analysis of the remains, and in particular the imposing size of some of the wells, allows us to deduce their public or semi-public function and, for the first time, the existence of hydraulic water drawing devices. As seen in other cities in the Roman world, this system associated with cisterns/reservoirs can supply and distribute water on the pressure.
In a context of water scarcity at the top of the hill, the cisterns made it possible to collect and conserve rainwater. The extensive confusion between cisterns and reservoirs in the older and recent scientific literature has forced us to include as many criteria as possible in seeking to provide more reliable interpretations of these structures. Our new certainties on the dating of the Brévenne and Gier aqueducts as well as our knowledge of their arrival altitude have been fundamental to reaching a better understanding of the function of these facilities. The cisterns were mainly located on the upper part of the hill. Their dating, unfortunately uncertain in the case of half of these structures, nevertheless shows that they were built over a fairly long period, mainly between the reigns of Augustus and Claudius, but sometime up to the end of the 1st century AD. The arrival of running water from the aqueducts had an impact on the construction of this type of facility, which no longer had the same role as before as a primary source of supply.
Cisterns were usually installed on the edge of hillside terraces or below large open spaces, where they could also provide support. The available data often enables us to link them with private buildings, but it is more difficult to connect them with public complexes.
Excluding the spring-fed facilities on the slopes, the documented fountains show the existence of a direct water supply from the aqueducts. The oldest remains, dated to the 1st century AD, are found in two sectors of the ancient city. First on the Sarra plateau, where the Verbe Incarné fountain was found and dated to the middle of the 1st century AD, which was supplied by the Brévenne aqueduct. This aqueduct is also probably the source of the water supply to the monumental nymphaeum to the south of the theatre. In the 2nd century AD, the same district was home to a larger number of fountains, which met the needs of the people who frequented the theatre and the odeon. It is likely that the large number of fountains documented in this area during that period is related to the arrival of water from the Gier. In the middle of the 2nd century AD, the operation on the Verbe Incarné fountain indicates the continued presence of an ancient water point, but also the need to renovate the previous network.
The well-documented public thermal baths are located at an altitude of 240-250 m NGF. They are indeed in an area which could easily be supplied with water by all the aqueducts. However, for the oldest thermal baths, i.e. those of the very recently discovered Antiquaille, it is likely that the first complex, dating from 30-20 BC, was fed by a rainwater cistern or by a spring. As far as we know, no aqueduct had yet come into operation at that time. Conversely, it might have received its water supply from the Yzeron aqueduct at the time when the complex was transformed during the reigns of Tiberius and Claudius. The existence of a constant water supply to the district at that time seems to be confirmed by the private thermal baths documented in the area. The Brévenne aqueduct, built by Claudius, is the one that was required to serve Lyon’s biggest thermal baths, those in the rue des Farges. Their construction in the middle of the 1st century AD and the commissioning of the aqueduct at the same time are probably related.
The available data, which is dispersed and often old, needs complete revision, but the many contributions of preventive archaeology on the hydraulic structures as well as on the urban occupation of the hill will enlighten us in the coming years. As always, teamwork will be the essential factor needed to arrive at a new synthesis on the subject.
- français
Sur la colline de Fourvière à Lyon, qui atteint une altitude maximale de 298 m NGF environ, les édifices publics, les thermes, les fontaines, les réservoirs ainsi que les maisons et les installations privées étaient desservis en eau par les quatre aqueducs lyonnais (Mont d’Or, Yzeron, Brévenne et Gier). Cependant, la mise en service de ces grands ouvrages a couvert une période de plus d’un siècle entre les règnes d’Auguste et d’Hadrien.
Les contraintes liées à la topographie de la colline sur laquelle s’est installée la colonie romaine ont rendu difficile l’alimentation des quartiers localisés dans la partie la plus haute, qui ne seront que partiellement approvisionnés en eau courante par l’aqueduc de la Brévenne à partir du milieu du ier s. apr. J.-C. et complètement par l’aqueduc du Gier dans la première moitié du iie s. apr. J.-C. D’autres types d’ouvrages hydrauliques, exploitant d’autres sources d’approvisionnement (nappe phréatique et eau pluviale), ont été nécessaires pour l’acheminement de l’eau sur une longue durée.
Ce recensement des puits, citernes, réservoirs ainsi que des fontaines et des thermes vise à réaliser une synthèse des différentes formes d’alimentation et de distribution de l’eau sur la colline de Fourvière pour comprendre le rapport de ces ouvrages et des aqueducs avec le développement urbain de la colonie.
