An investigation into the hydraulic installation of Ostia and Pompeii as contribution in understanding aquatic performances in Roman theatres

Abstract

This PhD project presents a rigorous method in the study of the theatre’s water operation system, disclosing the engineering, architectural and urbanistic complexity behind it.
Research of theatres in Antiquity addresses a distinctive gap in the investigation of hydraulic installations. This involves water supply and drainage systems. The former is associated with the performance of aquatic displays and the operation of other water features (id est fountains) that may have been present; the drainage systems are essential for the functioning of the theatre and of the water supply system itself. Taking the move from the questions ‘how did this water operation system work?’ and ‘why was it designed according to this scheme?’, two case studies are selected for addressing and answering to these questions. Among the theatres used to host aquatic displays, Pompeii and Ostia have been chosen for the different solution adopted for the water supply and distribution systems, the type of installation where these performances were staged (basins and κολυμβήθρα), and their differing and therefore complementary chronology (Late Republic and Late Empire). If the preliminary analysis of the published data available are constrained by the lack of data available, allowing mainly consideration on the geographical distribution of these installations across the Italian peninsula, the deeper investigation of the two case studies goes beyond. Adopting an interdisciplinary approach was crucial to investigate the complex nature of water management in theatre buildings. Various methods are used, from archive research to geophysical survey, GPS/total station survey, structural stratigraphic analysis, photogrammetric survey, 3D modelling, and, for the first time in these settings, hydraulic engineering calculations. This interdisciplinary approach involves also the study of the environmental and urban context of the building site. Indeed, the architectonic and engineering design of hydraulic installations are determined by considerations related to the introduction of the new infrastructure within an already existing water supply and sewerage network, as well as structural restrictions. These usually neglected aspects highlight how the study of the hydraulic installations in theatres must be understood within the wider urban context, which is in turn affected by the geomorphological conditions. Natural events also affect the buildings themselves, resulting in subsequent changes to their structures.
This thesis shows that the design and construction of hydraulic installations in theatres are closely linked to the geomorphological characteristics of the construction site (natura loci), the use of the building itself (utilitas), and its aesthetic appearance (venustas) (Vitr.DeArch.1.2-1.3). These factors continue to influence the building throughout its existence. Whether it is impossible to separate the different types of solutions adopted in these theatres from the different types of water use that these structures operated, the importance of aquatic displays are proved by the massive intervention applied in earlier theatre’s structures. Conclusively, it is possible to infer that cultural needs and changes of taste determines the reconfiguration of theatres’ layout. In one case from the project phase (Pompeii) or as adaptation (Ostia), to ensure the continuation of aquatic performances.