L’eau à Ostie et dans le delta du Tibre: la gestion d’une ressource à risque

The Roman colony of Ostia was founded in an area that was hardly suitable for the construction of a city. The Tiber delta plain was a swampy area made up of brackish lagoons (in particular the ponds of Ostia and Maccarese) and various swales, located between the various beach ridges at the origin of the progradation of the coastline in this part of the Tyrrhenian coast. In addition, the Tiber was a great danger due to its periodic flooding and its progressive migration of the riverbed. These phenomena led to the erosion of some of the infrastructure close to the river. The Romans, therefore, had to cope with these natural constraints and solve the problems they posed with appropriate engineering solutions. Despite the challenges posed by this swampy environment, the area also proved to be a favourable place for the development of certain activities: it was an important source of salt for Rome and an important trading point between the Mediterranean and central Italy. The aim of this article is to propose various insights into the management of this ambivalent environment, with a view to carrying out a more detailed study in the future. Such research will be fundamental for a better understanding of the resilience of the city of Ostia and its territory.