Tigris–Euphrates river system Tigris–Euphrates river system The Tigris and Euphrates, with their tributaries, form a major river system in Western Asia. From sources originating in eastern Turkey, they flow by/through Syria through Iraq into the Persian Gulf. The system is part of the Palearctic Tigris–Euphrates ecoregion, which includes Iraq and parts of Turkey, Syria, Iran, Saudi Arabia, Kuwait, and Jordan. From their sources and upper courses in the mountains of eastern Anatolia, the rivers descend through valleys and gorges to the uplands of Syria and northern Iraq and then to the alluvial plain of central Iraq. The rivers flow in a south-easterly direction
Karasu (Euphrates) through a rocky gorge. Near the small town of Kemaliye it receives its last tributary, the Çaltısuyu, before turning sharply southeast to flow through a deep canyon into the Keban Dam Lake on the Euphrates. Before construction of the Keban Dam the Karasu joined the Murat River 10 km above the dam site and 13 km above the town of Keban. In 1996, 15 Turkish soldiers were killed when their personnel carrier fell into the river during a routine crossing. When temperatures in Turkey dropped below -25 °C in 2005 the river froze over and was used as a football