Shushtar Historical Hydraulic System

The Shushtar Hydraulic System in the island city of Shushtar is a complex irrigation system that dates back to the time of the Achaemenid king Darius the Great in the 5th century BCE. Described by UNESCO “as a masterpiece of creative genius”, the Shushtar Hydraulic System involved the creation of a diversion canal on the river Karun to form a moat around the city, over which bridges and gates were built to keep away unwanted visitors. A system of subterranean channels called Ghanats connected the canals to the private reservoirs of houses, buildings and watermills. These tunnels supplied water for domestic use and irrigation, as well as to store and supply water during times of war when the main gates were closed. Although this complex system of irrigation degenerated during the 19th century, traces of the Ghanats can still be found in the crypts of some houses. Photo credit: Darafsh Kaviyani/Wikimedia While the Shushtar water system has its roots in the Achaemenid times, much of its renovation and expansion was done in the 3rd century AD during the time of the Sassanids. The workers were Roman soldiers captured by the Sassanid ruler Shapur I following a battle with the Roman Emperor Valerian. Using the captured forces, the Sassanid ordered the building of a vast irrigation system consisting of a canal and two dams to control the water flow. The Ab-i Gargar canal branches off the Karun and rejoins the main river 50 km downstream, creating an island called Mianâb or "Paradise". Shushtar is located at its northern end while the rest was used for orchard plantations. The 500 meter long overflow dam located downstream over the Karun river is called Band-e Kaisar or “Caesar's Dam”, and was the key structure of the system responsible for retaining and diverting river water into the irrigation canals in the area. Another smaller barrage, the Band-e Mizan, was erected upstream to control the flow of water into the Ab-i Gargar canal.