[en] The choice of a harbour location is a strategic option and meets specific criteria. In addition to being a naturally favourable structural setting protected from currents and strong winds, harbours are sometimes associated with a channel which contributes to the optimisation of navigation and is an integral part of the port space. These waterways also play a major role in protecting shorelines and local residents, thus limiting fluvial risk by improving environmental control. The matter of artificial accesses to the port is a fundamental issue since the canal plays a role in its functioning as well as sometimes also in its decline. The diversity of forms and uses of these harbour approach channels will be analysed based on several examples from France. Although these waterways fulfilled similar purposes, their technical implementations show a great variety, which so far have rarely been the object of archaeological studies. Increasing numbers of discoveries of channels made over the last thirty years in France have provided new information for the understanding these developed waterways. Preventive archeology made a major contribution to this renewal of knowledge and made it possible to identify about twenty navigation channels, half of which can be traced back to Roman times. Currently, there is a growing interest in channels, and more particularly harbour channels, some of which –mainly concentrated around the Mediterranean Sea– are the subject of extensive research programmes. Excavations, coring or geophysical surveys provide information about the structure of the channels, the type of construction, and also about their environment. The inventory of channelled structures, initiated in 2015, revealed the presence of almost ten Roman harbours with harbour approach channels in France. Based on several examples, it is possible for the first time to draw up a typology of these channels. Even if these are less numerous compared to the Mediterranean Sea, there are several examples located on the Atlantic coast, and despite their architectural differences all aim to facilitate port activities and port maintenance. They also reflect the diversity of channelling processes, intrinsically linked to the boats they are intended to support. Despite still limited data, research on the Roman ports of the Atlantic coast and inland waters also reveals the existence of facilities which are perfectly suited to fluvial navigation. This initial approach is worth extending and should be put into perspective with other navigation channels identified in Roman Gaul and more generally in the Roman world.

[fr] Le choix d'implantation d'un port est stratégique et répond à des critères bien spécifiques. Outre une configuration structurelle naturellement favorable qui l'isole des courants et vents violents, le port peut être associé à un canal qui contribue à optimiser la navigation et fait partie intégrante de l'espace portuaire. Ces voies d'eau jouent également un rôle majeur dans la protection des rives et des riverains, limitant ainsi le risque fluvial grâce à une meilleure maîtrise de l'environnement. L'artificialisation de l'accès au port est une question fondamentale puisque le canal participe à son fonctionnement, mais aussi parfois à son déclin. La diversité des formes et des usages de ces canaux sera abordée à travers plusieurs exemples métropolitains. Si ces voies d'eau ont des finalités proches, leur mise en œuvre technique s'avère quant à elle très variée, mais peu d'études archéologiques lui sont dédiées.