Tunnel and ventilation design of the Eupalinos’ aqueduct in Samos, Greece

Abstract

Polycrates’ extended reign and a recently discovered extension of the distribution sector of the aqueduct prompted this review of the design and tunnelling of the Eupalinos’ aqueduct. Both aqueducts, the Archaic and Roman, cross an affluent area of the upper city, located less than 10 m below the level of the water source, a condition critical for the aqueduct’s design. The tunnel’s detour from its initial axis and the function of the tunnel as an integrated element of the city’s defensive works are also discussed. A key consideration of this review is the ventilation of the lengthiest blind segments of the Eupalinos’ tunnel, given that natural ventilation in a blind gallery is generally not effective beyond about 50 m. Considering the historical evolution of ventilation in underground works, it is proposed here that a ventilation circuit was maintained along the tunnel through an auxiliary gallery dug simultaneously a few meters below the tunnel.