Sennacherib's Canal System - Water Control in the Assyrian Empire
Assyrian Water Control Technology
By K. Kris Hirst
Archaeology Expert
The The Jerwan Aqueduct, built by King Sennacherib around 700 BC. Corbis via Getty Images / Getty Images
Updated August 14, 2016.
The Assyrian king
Sennacherib, son of
Sargon II, ruled Assyria between 705-681. He is best known for his engineering projects, which included an extensive canal system bearing water from the foothills of the Zagros Mountains southwestward to Sennacherib's capital city of Nineveh; the first known
aqueduct, at Jerwan; and a series of artificial lagoons and swamps as drain outflow for the canal. And, as historian
Stephanie Dalley has become convinced, Sennacherib may also have created the famous (and thus likely misnamed) "Hanging Gardens of Babylon".
Assyrian Canals
Although Sennacherib was not the only Assyrian king to build canals, he was certainly the most prolific. Canals were considered great engineering feats, and so (and luckily for us) they were described prominently in royal inscriptions of the day, such as that on the Taylor Cylinder. When they ascended to the throne, Assyrian kings would create a new capital city, build a new royal palace and canals, and force everyone to move there.
When Ashurnasirpal II [ruled 883–859] moved his capital to
Nimrud, he built a canal from the Greater Zab River to the left bank of the Tigris. When Sargon II moved his capital from Nimrud to Khorsabad in 717 BC, he built canals to
Khorsabad.
And when Sennacherib moved his capital from Khorsabad to Nineveh, he built several canals, constructed in four stages over a period of about 15 years, ending up with the massive Northern and Khinis canal systems.
Senacherib's Canals
- Kisiri Canal | built 702 BC | length 13.4 km (8.3 mi) | gradient 0.95 : 1
- Musri System | built 694 BC | unknown length and gradient
- Northern System | built ~690 BC | 46.4 km (28.8 mi) long | gradient between 0.6-0.4 : 1
- Khinis Canal | built between 690-688 BC | 55 km (34 mi) long | gradient 0.9 : 1
The Khinis canal was the longest of Sennacherib's efforts, part of a below-ground tunnel system. It began northeast from Nineveh, in the foothills of the Zagros Mountains at Bavian, and crossed the valley by means of the aqueduct at Jerwan. Nineveh's canals were maintained for some two centuries until they fell out of use during the Median and Babylonian administration of Assyria.
Much of Sennacherib's excavated canals have been mapped by Harvard archaeologist
Jason Ur's project using satellite imagery; according to Sennacherib's boasting, this massive effort was finished in 13 months, remarkable even by today's standards.
Water Sources and Purposes
Water sources for Nineveh's canals came from the Greater Zab river (a Tigris tributary), the Gomel/Khazir and the Rubar Dohuk. The canal tapped several springs along the way, and many of them were enlarged to form reservoirs. Jerwan is the only Assyrian structure which was specifically built to avoid runoff; most others were constructed to collect it. The canals were primarily for carrying water from the north to Nineveh, but Ur has identified offshoots from the canals where water was used to irrigate fields along the way. Most offshoots apparently did not exceed 2 m (6.5 ft) in width.
Canal size varied with location: near its head, the Khinis canal was 6 m (20 ft) wide and 2 m (6.5 ft) deep; but at Jerwan it had been expanded to between 19-22 m (62-72 ft) in width. Some segments of the Northern System canal are enormously wide, between 70-100 m (230-328 ft) in width. The routes of the canals were dictated by topography, bypassing prominences rather than excavating through them; the overall design gradient was 1 meter per kilometer (1:1000).
The Hanging Gardens
There's no doubt about it: Sennacherib had a way with gardens: he simulated forests in a park outside the city, and created a Babylonian marsh with reeds and pigs. The canals likely irrigated the gardens in the city, and, if there were any gardens on the grounds of the elevated palace at Kuyunjik, those were likely irrigated as well. According to Stephanie Dalley, Sennacherib's lavish gardens may have been the location of the
Hanging Gardens of Babylon: it's quite possible that the Greek historian
Herodotus was wrong about where the Hanging Gardens were at; certainly no evidence of such a garden has been found in Babylon.
Inscriptions
Luckily for us, Sennacherib was proud of his accomplishments and bragged about them in several extant inscriptions. Among them is the Taylor Prism, an octagonal fired clay object currently at the British Museum, one of at least three carved during Sennacherib's reign. Its
cuneiform texts include a description of water control methods which included "great beams and wooden frameworks over the well-shafts" which most scholars interpret as shadoufs. Dalley suggests alternatively that Sennacherib used a
water screw, predating
Archimedes by about 400 years: and she may very well be right: using a shadoof to raise water would have been very labor-intensive.
The Bavian inscription, located near the head of the Khinis canal and written in 690 BC, reports that Sennacherib built 18 canals, which irrigated Nineveh's fields annually so that they could cultivate grain and sesame. Inscription B at Jerwan reports that he added "to the waters of the River Pulpullia and the towns and springs, caused a canal to be dug to the meadows of Nineveh, and a bridge of white stone blocks."
WTF!?
