The Balikh River is a perennial river that originates in the spring of Ain al-Arous near Tell Abyad in the Eastern Mediterranean conifer-sclerophyllous-broadleaf forests ecoregion. It flows due south and joins the Euphrates at the modern city of Raqqa. The Balikh is the second largest tributary to the Euphrates in Syria, after the Khabur River. It is an important source of water and large sections have recently been subjected to canalization.