According to Iran’s National Committee on Irrigation and Drainage, the structures are Si-o-se-pol in Isfahan, Amir bridge-dam in Fars province, Shadorvan bridge-dam in Khuzestan province, and the historic hydraulic structures of Siraf in Bushehr province.
The four sites have been recognized as outstanding examples of Iran’s historic water engineering and indigenous knowledge of water management.
The National Committee on Irrigation and Drainage said a commemorative award ceremony for the newly registered structures will be held during the 26th International Congress on Irrigation and Drainage, scheduled to take place in Marseille, France, in October 2026.
Mehrzad Ehsani, secretary of Iran’s National Committee on Irrigation and Drainage, said the WHIS program is an initiative of the International Commission on Irrigation and Drainage (ICID) aimed at identifying and preserving historic water-management structures.
“The World Heritage Irrigation Structures program is one of the initiatives of the International Commission on Irrigation and Drainage, which has been implemented in recent years to help identify, introduce, preserve and maintain these valuable historic structures,” Ehsani said.
He explained that structures nominated for inclusion in the WHIS list must be at least 100 years old while remaining active and functional.
“Iran has numerous water structures because of its long civilizational history, but each national committee can nominate only four water structures every year,” Ehsani said.
He added that 12 historic Iranian water structures have so far been nominated by Iran’s National Committee on Irrigation and Drainage and registered by the ICID since the launch of the program.
Si-o-se-pol
Si-o-se-pol, also known as Allahverdi Khan bridge, is one of Iran’s best-known historic bridges.
Built during the reign of Safavid King Shah Abbas I, the bridge was constructed over the Zayandeh Rud river in Isfahan under the supervision of Allahverdi Khan and based on the design of master architect Hossein Bana Esfahani.
The bridge is 295 meters long and 14 meters wide and features 33 arches, from which it derives its name, meaning “33 bridges” in Persian.
Si-o-se-pol is widely regarded as a masterpiece of Iranian architecture and bridge engineering.
Band-e Amir
Band-e Amir is a historic bridge-dam located in a village of the same name, about 45 kilometers from Shiraz, across the Kor River in Fars province.
The structure dates back to the Buyid or Daylamite period and takes its name from Adud al-Dawla, the most prominent ruler of the Buyid dynasty, which controlled parts of Iran and Iraq.
Situated at the edge of the vast Marvdasht plain, Band-e Amir represents an early example of engineering designed to regulate and manage river water for the surrounding agricultural lands.
Shadorvan bridge-dam
The Shadorvan bridge-dam in Shushtar, Khuzestan province, is attributed to the Sasanian period and is considered one of the world’s oldest surviving bridge-dams.
Its distinctive engineering and architectural features made it an important component of the historic water-management system of Shushtar, an area renowned for its sophisticated network of dams, canals, bridges and watermills.
The structure demonstrates the advanced understanding of hydraulic engineering developed in ancient Iran and its use in managing river flows and supporting agriculture and urban life.
Historic hydraulic structures of Siraf
In southern Iran, the historic hydraulic structures of Siraf in Bushehr province represent a different form of indigenous water-management knowledge, adapted to the region’s hot and arid environment.
Archaeological and historical research has linked the water-related structures carved into the Lir valley at Siraf to systems developed to collect, supply and store water for the ancient port city.
The inclusion of the four structures in the WHIS list further highlights Iran’s long history of hydraulic engineering and the role of water management in the development of its ancient settlements and civilizations.