Tigris and Euphrates Rivers

Waters from the tigris (in arabic Dijla, in Turkish Dicle) and Euphrates (in Arabic Furat, in Turkish Firat) Rivers gave rise to some of the first known agricultural civilizations. These early societies of the Mesopotamian plain arose with irrigation techniques and water infrastructure dating back to 4000 b.c.e. and earlier. The Tigris and Euphrates Rivers are also well known for their high inter-annual and seasonal variability, leading to intense flooding with maximum flows as much as 10 times minimum flows. Sediment loading on the rivers is also high, resulting in raised river beds that historically have facilitated irrigation.

The “twin rivers” begin approximately 30 kilometers from each other in the highlands of eastern Turkey, travel through Syria and Iraq, and join together as the Shatt al Arab for 150 kilometers before draining into the Persian (or Arab) Gulf. The [Page 1737]Euphrates extends a total of 2,700 kilometers (40 percent in Turkey, 35 percent in Iraq, and 25 percent in Syria); the Tigris travels 1,900 kilometers (20 percent in Turkey, 78 percent in Iraq, and 2 percent in Syria). The mean flow of the Euphrates is approximately 30 billion cubic meters per year (BCM/Y); and the Tigris conveys considerably more after contributions from tributaries in Iraq, with approximately 50 BCM/Y.

Water diversion and damming of the twin rivers for irrigation and other uses continues today with major engineering works pursued by all three riparians (Turkey, Syria, and Iraq) for agriculture, hydroelectricity generation, and to overcome flooding and the intense seasonality of the rivers. In Turkey, there are approximately 20 dams completed or planned that comprise the GAP project (Southeastern Anatolia Project, with the Atatürk dam the largest among them, filled in 1991). In Syria, several large dams are in operation, including the Tabqa dam, completed in 1975 with the aid of Soviet engineering and financing during the Cold War. In Iraq, large reservoirs include Lake Abu-Dibbis, Lake Habbaniyah, and Lake Tharthar (serving flood control and facilitating water transfers from one river to another).

Planned future use of the rivers by all three countries is estimated to outstrip available freshwater supply by 148 percent on the Euphrates and 111 percent on the Tigris. Given this, the Tigris-Euphrates basin is often cited as a potential site of future water-related conflict, with troops already having been deployed to the Syria-Iraq border in the 1970s over water use conflicts; diplomatic hostilities that have led to decades-long stalemates and the absence of a tripartite water sharing agreement (there is, however, a 1987 agreement between Turkey and Syria guaranteeing 500 cubic meters per second of Euphrates water to flow over the border, and a 1990 agreement between Syria and Iraq, but none involving all three countries); as well as regional and international concern over Turkey's use of the river waters with continued implementation of the Southeastern Anatolia Project.

As Turkey's GAP project involves damming and water diversions on both rivers, it threatens to reduce the quantity and quality of freshwater for downstream Syria and Iraq—figures cited are as high as a reduction of 80 percent of Euphrates flow for Iraq, and 60 percent for Syria. Within Turkey, water diverted for irrigation has led to considerable agroecological and societal changes in the Southeastern Anatolia region and poses long-term sustainability concerns, such as issues related to pollution and salinization. There are also important implications of the project for the long-standing Kurdish conflict, as Kurdish populations occupy areas around the rivers in all three countries, and as former Turkish President Özal is said to have threatened Syria with cutting off flow of the Euphrates if it did not stop support for Kurdish insurgents.

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