[4] The approximately 500m long overflow dam over the Karun, Iran's most effluent river, was the core structure of the Shushtar Historical Hydraulic System (سازههای آبی شوشتر) from which the city derived its agricultural productivity.
[9] According to Persian tradition, the Band-e Kaisar is named after the Roman emperor Valerian (253–260 AD), who was captured with his entire army by the Sassanid ruler Shapur I after having been defeated in the Battle of Edessa (260).
This vast labour force, which may have numbered up to 70,000 men and included the Roman engineering corps, was employed by the victors for construction work in Shushtar, an important agricultural center in south-western Iran.
[13] Modelled on the Roman example, the integration of a bridge superstructure into dam design became a standard practice of Iranian hydraulic engineering which lasted until about 1000 AD, when it culminated in the still existing Band-e Amir at Shiraz.
[20] The typical clear span of the Pol-e Kaisar was between 6.6 and 9 m.[7] The piers, protected on their upstream side by pointed cutwaters, were of rectangular shape and pierced by high-set floodways; their considerable thickness of 5 to 6.4 m restricted the waterway by nearly one-half.
[21] The facing of the piers and the foundation consists of cut sandstone blocks bonded by mortar and joined by iron clamps; the interior was filled with Roman concrete,[22] a building technique also observed in the Pa-i-pol bridge.
[12] Finally, another smaller barrage, the Band-e Mizan, whose construction may postdate the Roman works, was erected upstream to control the flow of water into the Ab-i Gargar canal.