Babylon is located on one of the branches of the Euphrates River (buranun in Sumerian and purattum in Akkadian), which flows for 2850 km.
The course of the Euphrates
It originates north of Lake Van in the mountains of Armenia, and after several changes of direction, it ends up very close to the Tigris River as it enters Babylonia.
The course of the Euphrates then bends one last time to flow southward, dividing into several branches, before getting lost in the swamps. Its waters then mix with those of the Tigris and join the Persian Gulf.
Throughout its Mesopotamian course, the Euphrates receives two regular tributaries: the Balih and the Habur. The river's regime experiences a spectacular flood in spring (April-May), linked to the massive snowmelt in the mountains of eastern Anatolia.
The arms of the Euphrates
The Euphrates is divided into several branches. The first passes through Nippur - called the "Euphrates of Nippur" - and continues through the Nar-sharri ("King's Channel"), connecting the cities of Nippur and Uruk. The second, called Arahtu, runs through the city of Babylon. A western branch, the Pallukkatu, leaves the main river north of Sippar and brings water west of Borsippa, where it supplies the marsh region. In addition, the branches of the Euphrates themselves are subdivided into canals. Thus in Babylon, there are several canals, such as the Libil-hegalla, located south of the palace complex.
The control of the Euphrates
The Babylonian rulers tried to control the course of the Euphrates, and especially to keep it in its bed during its spectacular floods. However, it is admitted that the internal topography of Babylon underwent a profound change in the Persian period. Herodotus tells in his Histories that in the 5th century B.C., the river still divided Babylon into two parts, but that the royal palace and the "temple of Zeus-Bel" were then on two different banks. It is accepted that the Euphrates left its bed around the middle of the fifth century.