Karun

The Kārun (also spelled as Karoun) is Iran's most effluent, and the only navigable, river. It is 450 miles (720 km) long. It rises in the Zard Kuh mountains of the Bakhtiari district in the Zagros Range, receiving many tributaries, such as the Dez and the Kuhrang, before passing through the capital of the Khuzestan Province of Iran, the city of Ahwaz.