Investigating the Function of the Water System of the Ancient Site of Tchogha Zanbil: A Field Survey and Hydrologic-Hydraulic Modeling

The ancient site of Tchogha Zanbil was a complex in the Elamite city of Dur Untash. It was protected inside three concentric walls. The ziggurat, temples and palaces and other urban facilities were inside the walls of the ancient city. Tchogha Zanbil is also famous because of its water technologies, especially the water system in the third enclosure of the ancient site. Roman Ghirshman (1895-1979) who carried out the main excavations at the site supposed that it was a water refinery system for the use of the city inhabitants. Nevertheless, the high altitude of the ancient city and the lack of evidence of the existence of a canal from the Karkheh River raise the question of the function and mechanism of this water system. The possibility of the system to have been a drainage system or a reservoir to save water is also precisely studied. Geological surveys of natural drainage paths, examination of the discharge of urban runoff, and biological and environmental studies were carried out. Documentation was carried out with a laser scanning system, as well as geophysical and hydrological surveys that were used to map the inner channels of the system. Finally, the studies show that the draining function can be a plausible hypothesis in view of hydraulic engineering for the Tchogha Zanbil water system.