Karkheh

The Karkheh or Karkhen is a river in Khūzestān Province, Iran (ancient Susiana) that springs in the Zagros Mountains and flows west of Shush (ancient Susa), finally dropping into the Tigris near its confluence with the Euphrates. In current times, it turns southwest after passing within 16 kilometers (10 mi) of the Dez River, then northwest of Ahvaz, and is absorbed by the Hawizeh Marshes that straddle the Iran–Iraq border. Its unusually delicious water was revered by the Persian rulers. Because the Karkheh's bed has shifted through time, and a neighboring watercourse between the Karkheh and the Dez River, the Shaur, complicates the identification, ancient names for the Karkheh should be viewed as conjectural.

The difficulty with the old names is that, while the Karkheh runs a kilometer or two west of Susa, another large watercourse flows parallel to it a few kilometers east of Susa. When these rivers reach the flood stage, the waters of the two rivers mix and flood the whole area south of Susa. The Shaur, a stream a few kilometers east of Susa, runs east between the Haft Tepe and Shaur mountains into the Dez River, north of where the Dez and Karun rivers converge. The Karkheh may have joined the eastern end of the Shaur at some point in the past. The precise time of these modifications is unknown.

Total Length: 559 miles