The importance of navigable waterways to the economy of Mesopotamia cannot be overestimated. The code of Hammurabi, from which we have already cited several extracts, includes laws that regulate navigation on the rivers and canals. It sets compensatory payments for shipwrecks or breakdowns, and establishes right-of-way rules:
“If a boat traveling upstream collides with and sinks a boat traveling downstream, the owner of the sunken vessel will officially declare, in the presence of God, all that was lost in his boat, and the boatman of the upstream-traveling vessel that caused the sinking will pay for the boat and everything that was lost.”lz-
Several of the canals flow by gravity from the Tigris toward the Euphrates, reflecting the ancient confluence that existed in the IIIrd millennium BC in the region of Sippar (Figure 2.1). This did not go unnoticed by Greek observers, Herodotus in particular (this extract comes after the text cited earlier regarding irrigation):
“Babylon is in its entirety, like Egypt, crisscrossed by canals; the largest one is navigable, oriented in the direction of the winter sunrise, and joins the Euphrates to the Tigris, the river on which Nineveh is situated.”
According to Xenophon, four of these large canals are very respectable in size: “Here also are the canals, which flow from the Tigris river; they are four in number, each a plethrum wide (about 30 m) and exceedingly deep, and grain-carrying ships ply in them; they empty into the Euphrates and are a parsang (about 5.5 km) apart, and there are bridges over them.”1-3
These canals also have a strategic function in the context of the Assyrian domination. The Assyrian capital Nineveh is indeed located on the Tigris as stated by Xenophon. At that time this river disappeared into the swampland and was not navigable to its mouth. Therefore the canals between the Tigris and the Euphrates enabled boats to get to the Persian Gulf from Nineveh. In about 700 BC a flotilla constructed at Nineveh for the Assyrian king Sennacherib descends the Tigris to Opis; it then transits across to the Euphrates in anticipation of a military operation in the Persian Gulf. It is this same Sennacherib, exasperated by numerous revolts against the Assyrian power, who destroys Babylon in 689 BC — not only by fire, but also by water. He floods the city using a branch of the Euphrates, called the Ahratum, that flows out from Sippar.
But later on, in the age of the Achaemenid Persians, it is by contrast from the Persian Gulf that invasions were dreaded. The Persians were not sailors; they decided to block navigation on the Tigris and Euphrates by constructing weirs across them. They brought traffic to a standstill on the two great arteries of the country. When Alexander the Great later becomes master of the country, he removes these weirs as a gesture of liberation.[44] [45] [46]
