Representing the operation and evolution of ancient Piraeus’ water supply system

The newly excavated urban water supply system of the city of ancient Piraeus provides an excellent opportunity for the study and evaluation of the issues of sustainability, adaptability, simplicity and environmental protection, which are of main concern in modern engineering design practices. Well-digging in the area of Pireaus dates back to the city’ founding during the Classical period. However, scarcity of groundwaters stimulated development of water harvesting techniques, mainly cisterns for the collection of rain water, and to the gradual increase of their capacity in order to avoid overflows. Changes to land plot areas and the increase in water demand during the Hellenistic period affected the operation of cisterns triggering a variety of subterranean constructions that expanded the existing capacity. During the Roman period, the city’s water needs for domestic and public use skyrocketed beyond the supply capacity of the water resources of the Piraeus’ peninsula. On account of this, an aqueduct which transferred water from outside the peninsula was constructed in the 2nd century AD, while cisterns and wells were gradually abandoned. The present paper examines the operation of ancient Piraeus’ urban water supply system and its evolution across nine centuries by studying the operation and evolution of cisterns through a combination of excavation finds (from the Ephorate of Antiquities of Piraeus and the Islands) and quantitative techniques. Water consumption during several historical periods and the available water resources of the peninsula were quantified and a hydrologic model was developed to simulate the daily operation of the cisterns over an 82-year period. Various circumstances were examined by running numerous scenarios for the: (a) magnitude of collecting area, (b) annual water demand, and (c) capacity of the cisterns. For each scenario, the reliability of the hydro-system for supplying residences with water was estimated. Simulation results were then correlated with specific socio-economic characteristics of the corresponding historical periods.