Nahrawan Canal

The Nahrawan Canal (Persian: کانال نهروان) was a major irrigation system of the Sasanian and early Islamic periods in central Iraq, along the eastern banks of the Tigris and the lower course of the Diyala River.

[1] The large-scale canal system of early medieval times however was created in the reign of the Sassanid ruler Khosrow I (r. 531–579), who also established it as a separate administrative district (Bazidjan Khusraw).

[1] In early Islamic times, the town of Jisr al-Nahrawan in the middle of the canal was the site of the Battle of Nahrawan on 17 July 658 between Rashidun caliph Ali and the Kharijites under Abd Allah ibn Wahb.

The initial feeder canal drawing water from the Tigris at Dur al-Arabaya near Samarra and carrying it to the Diyala at Ba'quba was called al-katul al-kisrawi ('the Cut of Khosrau').

During its course, it was joined by three smaller canals taken from the Tigris, the Yahudi ('of the Jews'), the al-Ma'muni, named after Caliph al-Ma'mun (r. 813–833), and the largest of the three, the Abu al-Jund ('father of the army'), built under Harun al-Rashid (r. 786–809).

From there, the main canal, now known as the Tamarra, turned south to the towns of Bajisra (originally Bayt al-Jisr, 'bridge-house') and finally Jisr al-Nahrawan, from where it was known as the Nahrawan proper.