The Tigris River originates in the Taurus Mountains of the eastern highlands of Turkey, and flowing South-East through Iraq it joins the Euphrates River, with which it forms the Shatt al-Arab river that empties into the Persian Gulf. The Tigris flows swiftly and receives many tributaries.
The lower Tigris is connected to the lower Euphrates (before the two permanently converge) by a series of semipermanent natural channels and ancient man-made canals.
Historically, the Tigris experienced regular flooding. Dams in Turkey and Iraq have altered the environmental (including flood) regime on the Tigris
The trade importance of the Tigris has declined with improved road and rail connections within Iraq. However, Basra, at the junction of the Tigris and the Euphrates, remains Iraq’s chief port.
The Tigris River flows through multiple riparian states until it empties into the Persian Gulf. Many of these riparian states have longstanding historical conflicts regarding the use of the river's water. 
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- Transboundary Freshwater Dispute Database (TFDD) (2012). Oregon State University. Tigris-Euphrates Case Study — The Transboundary Freshwater Dispute Database (TFDD) This website is used to aid in the assessment of the process of water conflict prevention and resolution. Over the years we have developed this Transboundary Freshwater Dispute Database, a project of the Oregon State University Department of Geosciences, in collaboration with the Northwest Alliance for Computational Science and Engineering.
- ^ The Tigris River. The Columbia Encyclopedia, 6th ed.
- ^ Product of the Transboundary Freshwater Dispute Database, Department of Geosciences, Oregon State University. Additional information about the TFDD can be found at:http://www.transboundarywaters.orst.edu/research/case_studies/Tigris-Euphrates_New.htm