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
Euphrates Iraq, there are no more natural tributaries to the Euphrates, although canals connecting the Euphrates basin with the Tigris basin exist. The drainage basins of the Kara Su and the Murat River cover an area of and , respectively. Estimates of the area of the Euphrates drainage basin vary widely; from a low to a high . Recent estimates put the basin area at , and . The greater part of the Euphrates basin is located in Turkey, Syria, and Iraq. According to both Daoudy and Frenken, Turkey's share is 28 percent, Syria's is 17 percent and that of Iraq