A canal is a human-made waterway that allows boats and ships to pass from one body of water to another. Canals are also used to transport water for irrigation and other human uses.
The most spectacular canal of this period was probably Nahrawān, 122 metres (400 feet wide) and 322 km (200 miles) long, built to provide a year-round navigation channel from near Sāmarrāʾ to Al-Kūt, using water provided by damming the unevenly flowing Tigris.