Arid Lands Newsletter--link to home page No. 44, Fall/Winter 1998
Conflict Resolution and Transboundary Water Resources

The Euphrates-Tigris basin: An overview and opportunities for cooperation under international law

by Ibrahim Kaya

"The principle of equitable utilization is grounded in the doctrine of limited territorial sovereignty and integrity within a given river basin. Under this principle, a basin state's sovereign rights to the waters of international rivers within or adjoining its territory are limited by the corresponding sovereign rights of other basin riparians."

Editor's Note: This work is partly based on a paper presented at "Water Resources Outlook for the 21st Century: Conflicts and Opportunities," 1-6 September 1997, in Montreal, Canada.


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Shared freshwater resources frequently cause international tensions, especially in arid or semiarid regions where these resources are scarce. Turkey, Syria and Iraq are the main riparians to the Euphrates-Tigris basin of the Middle East, whose waters seem unlikely to satisfy entire present and future needs of its riparians. Scarcity in the basin stems from unilateral, unintegrated development projects as well as natural conditions. So far the three major riparians have not reached a comprehensive watercourse agreement to ensure sustainable water management in the basin. This paper examines the current problem in light of relevant rules of international law, with the aim of promoting cooperation among the riparians.

Geography and Hydrology of the Euphrates-Tigris Basin

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Both the Euphrates and Tigris Rivers rise in the mountains of eastern Turkey and join the sea at the head of the Persian Gulf. The Euphrates enters Syrian territory at Karkamis, downstream from the Turkish town of Birecik. It is joined by its major tributaries, the Balik and Khabur, as it flows southeast across the Syrian tablelands before entering Iraqi territory near Qusaybah.

The Tigris flows through Turkey until the border city of Cizre; from there, it forms the border between Turkey and Syria for 32 km, then crosses into Iraq at Faysh Khabur. Within Iraq, it gathers several tributaries (the Greater Zap, The Lesser Zap, the Adhaim, and the Diyala) from the Zagros Mountains to the east.

The Tigris and Euphrates unite near Qurna, in Iraq. The combined flow, called Shatt al-Arab, empties into the Gulf (Kliot 1994).

The Euphrates basin lies 28% in Turkey, 17% in Syria, 40% in Iraq and 15% in Saudi Arabia. The river is 3,000 km long, divided between Turkey (1,230 km), Syria (710 km), and Iraq (1,060 km). Contrary to this distribution, the catchment area that produces inputs into the river is situated with 62% in Turkey and 38% in Syria. It is estimated that Turkey contributes 89% of annual flow and Syria contributes 11% (Naff and Matson 1984); one expert estimates the percentage of the Euphrates flow originating in Turkey as high as 98% (Kolars 1986). The remaining riparians contribute very little water.

The Tigris basin is distributed between Turkey (12%), Syria (0.2%), Iraq (54%) and Iran (34%). The catchment area producing the water of the Tigris is situated in Turkey (21%), Syria (0.3%), Iraq (31%) and Iran (48%). The river is 1,850 km long, with 400 km in Turkey, 32 km in Syria and 1418 km in Iraq (Kliot 1994). Turkey provides 51%, Iraq 39%, and Iran 10% of the annual water volume of the Tigris.

Not only the riparian states, but also scientists, have disagreed about the mean annual discharge of both rivers, mainly due to their annual and seasonal fluctuations. Estimates on the total annual flow of Euphrates vary between 28.7-30.5 billion cubic meters. The Tigris' estimated annual total flow is between 43-52.6 billion cubic meters.

These statistics already reveal a certain imbalance, in that only a few states are the source of most of the annual water supply whereas all states participate in its use. However, Saudi Arabia and Iran are not major riparians in this basin. Iran is riparian only to the Tigris; Saudi Arabia is riparian only to the Euphrates. Moreover, the Saudi Arabian stretch of the Euphrates dries in summer, and because of unfavorable geographic and climatic conditions Iran cannot use the waters of the Tigris for agriculture or hydropower. Therefore, these countries have generally been ignored in studies of the basin (Cohen 1991).

An overview of use of the Euphrates-Tigris basin: Development and disputes

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Iraq was the first riparian to develop engineering projects in the basin. The Hindiya barrage on the Euphrates was constructed between 1911 and 1914 to prevent flooding and transfer water to canals for year-round irrigation (Kliot 1994). In the 1950s Iraq built a second Euphrates barrage at ar-Ramadi. Like the Hindiya Barrage, its main objective was flood control and irrigation (Naff and Matson 1984).

Both Syria and Turkey were slow to develop use of the waters of the two rivers before the 1960s. During the second half of the 1950s the Russians conducted research on the Syrian reach of the Euphrates and proposed a dam at Tabqa. In 1966 a Syrian-Soviet agreement led to construction of the Tabqa High Dam. The dam, renamed al-Thawrah ("the Revolution"), was completed in 1973. A current Syrian water development called the Great Khabur Project is aimed at using the Khabur River for irrigation. Syria is also conducting technical studies for another irrigation project on the Tigris.

Turkey began constructing the Keban Dam on the Euphrates in 1966; production of electricity began in 1974. Turkey built the Karakaya Dam on the Euphrates in 1986, as part of the Southeastern (Grand) Anatolia Development Project (GAP) (Kolars and Mitchell, 1991). GAP includes 22 dams and 19 hydroelectric power stations to be built on the Euphrates-Tigris over an area "as big as Belgium" (Newspot 1992). Ataturk Dam, the heart of the GAP, was completed in 1992. The GAP also embraces other economic and social improvements, such as transportation, industrial employment opportunities, and improved education and health services. From Turkey's perspective, it is an integrated regional development.

As these examples indicate, each of these riparians to date has tended to develop its water use plans unilaterally, without regard to the needs of the other riparians, the environment, or the actual capacity of the basin. Although there have been some international efforts from foreign investors to coordinate projects to develop the rivers for the interest of all, a common joint development project has never become reality (Chalabi and Majzoub 1995).

On the contrary, the completion of the Keban and Tabqa Dams caused serious tensions among Iraq, Syria and Turkey. Following the start of construction of the Keban Dam, Syria launched a campaign against Turkey. Subsequently Turkey reassured Syria that the dam would not cause any considerable harm (Chalabi and Majzoub 1995). Controversy over the Tabqa Dam was more serious, driving Syria and Iraq to the edge of armed conflict in 1975. Iraq threatened to bomb the dam (Naff and Matson 1984). Both countries moved troops towards their common border (MEED 1975). Saudi Arabia, and possibly the Soviet Union, mediated; eventually the threat of war died down, after Syria released more water from the dam to Iraq. Although the terms of the agreement were never made public, Iraqi officials have privately stated that Syria agreed to take only 40 percent of the river's water, leaving the remainder for Iraq (Naff and Matson 1984).

Tensions again rose in January 1990 when Turkey began filling the Ataturk Dam reservoir. Both Syria and Iraq accused Turkey of not informing them about the cutoff, thereby causing considerable harm. Iraq even threatened to bomb the Euphrates dams (Cohen 1991). Turkey countered that its co-riparians had "been timely informed that river flow would be interrupted for a period of one month, due to technical necessity" (Turkish Ministry of Foreign Affairs 1995). Turkey also claimed that before the impoundment, it released more water than its commitment under the protocol of 1987 (to a total flow of 500 cubic meters/second [cm/s]) so that the downstream countries could store this additional water. Some independent academics also support the Turkish view that it took all necessary measures to avoid significant harm to the downstream states during the impoundment (Vesilind 1993). Iraq and Syria continue to call the Arab League states to unite against Turkey on the GAP issue; recently, they threatened to take legal action in order to obtain compensation, as well as to boycott British, French, German, and Belgian companies as they build a dam on the Euphrates (Al-Hayat 1996).

International water law and the Euphrates-Tigris: Prospects for cooperation

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International water law in general

Historically, upstream and downstream riparians have advocated extreme and self-interested theories:

  • Upstream riparians have promoted the theory of absolute territorial sovereignty: that any state may use any watercourse within its borders as necessary, without regard to downstream riparians.
  • Downstream riparians have claimed absolute territorial integrity, that is, the exclusive right to the natural, uninterrupted flow of the river from the territory of upstream riparians.
However, neither theory has received much support from legal writers or international tribunals, who tend to prefer the principle of equitable utilization.

The principle of equitable utilization is grounded in the doctrine of limited territorial sovereignty and integrity within a given river basin. Under this principle, a basin state's sovereign rights to the waters of international rivers within or adjoining its territory are limited by the corresponding sovereign rights of other basin riparians. A state may thus utilize the water to the extent that this use does not interfere with the reasonable utilization of other basin states.

Efforts to codify international law concerning watercourses date to the beginning of this century, but the most important efforts are recent: The International Law Association's (ILA) 1966 Helsinki Rules and the United Nations' 1997 Convention on the Law of the Non-Navigational Uses of International Watercourses (hereafter, the Helsinki Rules and the UN Watercourse Convention). The ILA, a non-governmental scholarly organization, adopted the Helsinki Rules in 1966 (ILA 1967). Delegates to this meeting proposed that international waters have to be shared equitably and reasonably. In 1970, the United Nations General Assembly gave the International Law Commission (ILC) the task of codifying and developing the law regarding "non-navigational use of international watercourses" (Resolution 2669; ILC 1994). The ILC's work ultimately resulted in the UN Watercourse Convention, opened for signature in 1997 (UN, 1997). Like the Helsinki Rules, the UN Watercourse Convention provides for the equitable and reasonable utilization of international watercourses. Both sets of rules list factors for determining what is reasonable and equitable, including: geography, hydrology, climate, past and present utilization, economic and social needs of the riparians, population, costs of alternative measures, other resources, practicability of compensation in instance of dispute, and how the needs of one riparian may be fulfilled without substantial injury to another riparian (Kaya 1997).

The Helsinki Rules, although widely accepted and broad in their scope, are not binding: the ILA has no lawmaking power. The ILC, a study commission created under the auspices of the United Nations, also has no lawmaking power; however, the provisions of the UN Watercourse Convention are binding upon ratifying countries and, to the extent that they represent customary international law, other states.

International water law in the Euphrates-Tigris case

The 20th century has witnessed various bilateral attempts at cooperation within the Euphrates-Tigris basin. In 1920 the French and British governments, as the mandatory powers in Mesopotamia, signed a treaty regarding utilization of the waters of the Euphrates and Tigris. Article 3 of this treaty provided that the two governments should set up a commission responsible for examining irrigation plans in the region (Berber 1959). The Turco-French Protocol, signed in 1930, committed the Turkish and French governments to coordinating any plans to use the waters of the Euphrates (Kliot 1994). The principle of mutual cooperation over water development was extended IN A Protocol annexed to the 1946 Treaty of Friendship and Good Neighbourly Relations between Turkey and Iraq (UN 1963). The agreement encompassed both rivers and their tributaries. At that time Turkey and Iraq agreed to share related data and consult with each other in order to accommodate both countries' interests. The 1946 treaty mandated a committee to implement these agreements. although none of this has yet occurred, Caponera (1993) pointed out that, if fully implemented, the 1946 Agreement would constitute a good basis for ensuring optimal cooperative water management between Turkey and Iraq.

There have also been one-sided gestures of cooperation. For example, in 1976 Turkey pledged to release 350 cm/s from the Euphrates downstream and in 1976 increased the minimum flow to 450 cm/s. This increase resulted from Turkey's effort to prevent possible armed conflict between Syria and Iraq, due to Syria's cutting off Euphrates River flow in 1975 to fill the al-Tawrah Dam (Kliot 1994). In 1987, Turkey agreed to increase the flow of the Euphrates to 500 cm/s.

The Joint Technical Committee for Regional Waters was established between Turkey and Iraq in 1982; Syria has participated since September 1983. The Joint Committee deals with all water issues among the basin riparians. It helps to ensure that the procedural principles of consultation and notification are followed as required by international law. For example, in the Committee's November 1989 meeting, Turkey informed its neighbors that the Euphrates' flow would be interrupted for one month and that, prior to the interruption, Turkey would release more water for accumulation in downstream reservoirs (Tekeli 1990). Nevertheless, the Joint Technical Committee's success to date has been limited to providing a forum for discussion.

One of the main points highlighted by the UN Watercourse Convention is the optimal and beneficial uses of watercourses (Article 5). Water allocation agreements, while certainly of central importance, are not the only tools for ensuring such optimal use. Conservation is another important component of water basin management schemes. Therefore, all of the Tigris-Euphrates basin riparians should take serious measures to conserve water immediately. First, they should implement modern irrigation methods; currently, the use of open irrigation canals, inefficient irrigation methods, and large-surfaced reservoirs cause serious water loss, especially in the arid and semi-arid reaches of the two rivers. Another important tool for maximizing the potential for equitable utilization measure is the treatment and reuse of wastewater. In addition, more emphasis should be given to the selection of suitable crops, such as those that require less water to grow or that tolerate more saline water. Land that is more fertile should be given priority for irrigation, and less fertile land should be allocated to crops that can be dry-farmed or to other uses entirely. All of these activities should be supported by various activities undertaken to promote public awareness of the problems involved and their potential solutions.

Article 3 of the UN Watercourse Convention encourages riparian states to conclude watercourse agreements that will apply the principle of equitable and reasonable utilization to a particular international watercourse. To determine the equitable and reasonable share of each party, all parties can cooperate on joint basin-wide studies to collect data and inventory land and water resources. Under the Helsinki Rules and the UN Watercourse Convention, such an agreement should include a specific duty to provide prior notification of any planned work. The establishment of a joint watercourse institution to receive relevant information and evaluate the possible harmful effects of unilateral water development projects would facilitate the implementation of the agreement (Caponera 1996).

Claims of parties and dispute resolution under international law

Clearly, these riparians disagree on how to allocate the waters of the Euphrates-Tigris basin. Iraq and Syria maintain that they have acquired water rights relating to their existing irrigation projects in the basin. They object to any upstream water development project in Turkey that may affect the amount of water flowing into their territory. Iraq also claims that its water claims have priority over Syria's and objects to Syria's diversion of the Euphrates.

Overall, Iraqi and Syrian proposals for water allocation might be summarized as follows:

  • each riparian will notify the other riparians of its water demands on each river separately;
  • total potential water supply of each river will be calculated
  • if the total demand exceeds the total supply of a given river (as is sure to be the case), the "overdraft" amount will be deducted proportionally from the demand of each riparian state (Turkish Ministry of Foreign Affairs 1995).

To the degree that this position attempts to maintain the existing water utilization balance and prevent further water development projects in upstream countries, it reflects the theory of territorial integrity -- which is not accepted as the rule of international law. Furthermore, this approach would allow each riparian to determine its own water needs without independent verification, raising fears of falsely inflated demands in order to negotiate and gain more water.

For its part, Turkey proposed a "Three-staged plan for optimal, equitable and reasonable utilization of the transboundary watercourses of the Euphrates-Tigris basin" in 1984 (Turkish Ministry of Foreign Affairs 1995). This plan proposes that the riparians jointly conduct and complete:

  • Inventory studies for water resources (stage 1)
  • Inventory studies for land resources (stage 2)
  • Evaluation of water and land resources (stage 3)
This plan would promote objective data-gathering in the basin. After evaluation of all the data, proposed projects could be compared on their economic and social merits, and those deemed more beneficial could be implemented.

The three-staged plan conforms to the principle of equitable utilization. It considers the basin as a whole system, underlining the interdependence of its elements, as required by the UN Watercourses Convention. Furthermore, it allows an objective scientific study to determine the equitable use of the waters of the Euphrates-Tigris basin.


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International law cannot decide the allocation of the waters of the Euphrates and Tigris. Nonetheless, law provides a basis for negotiation. Equitable utilization is inherently flexible. It will not produce definitive solutions and allocations, but will serve as a foundation for negotiation and cooperation. An international watercourse agreement would lay down rights and obligations of riparians more precisely. In addition to the agreement a joint watercourse institution is necessary to realize cooperation among the watercourse states. To reach such an agreement, inventory studies of water and land resources of all the parties must be completed. This will enable them to base their needs on objective criteria, rather than subjective political ambitions.


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Al-Hayat. 1996. 14 February 1996, London.

Berber, F. J. 1959. Rivers in international law. London: Stevens and Sons.

Caponera, D.A. 1993. Legal status of the Shatt-al-Arab (Tigris and Euphrates) River basin. Austrian Journal of Public International Law 45:147-158.

_____. 1996. Conflicts over international river basins in Africa, the Middle East and Asia. RECIEL 5(2):97-106.

Chalabi, H. and Majzoub, T. 1995. Turkey, the waters of the Euphrates and public international law. In Water in the Middle East, legal, political and commercial implications, ed. J.A. Allen and C. Mallat. London: Tauris Publ.

Cohen, J. E.1991. International law and the water politics of the Euphrates. New York University Journal of International Law and Politics 24:503-556.

International Law Association. 1967. Helsinki Rules on the Uses of the Waters of International Rivers. In Report of the Fifty-second Conference Held at Helsinki, 477.

International Law Commission. 1994. Report of the International Law Commission. U.N. GAOR, 49th Sess., Supp. No.10, 195, U.N. Document A/49/10.

Kaya, I. 1997. The United Nations Convention on International Watercourses: Prospects for cooperation. Paper presented to International Conference on Large Scale Water Resources Development in Developing Countries, 20-23 October, at Kathmandu, Nepal.

Kliot, N. 1994. Water resources and conflict in the Middle East. London: Roudledge.

Kolars, J. F. 1986. Hydro-geographic background to the utilization of international rivers in the Middle East. American Society of International Law Proceedings 80:250-258

Kolars, J. F. and Mitchell, W. 1991. The Euphrates River and South East Anatolia Development Project. Carbondale, Ill.: Illinois University Press.

MEED (Middle East Economic Digest), 30 May 1975.

Naff, T. and Matson, R. C. 1984. Water in the Middle East: Conflict or co-operation. Boulder, Colo.: Westview Press.

Newspot, 13 August 1992.

Tekeli, S. 1990. Turkey seeks reconciliation for the water issues induced by the South East Anatolia Development Project (GAP). Water International 15(4):206-216.

Turkish Ministry of Foreign Affairs.1995. Water issues between Turkey, Syria and Iraq. Ankara: the Ministry.

UN (United Nations). 1997. United Nations General Assembly Resolution A/51/869.

_____. 1963. Legislative texts and treaty provisions concerning the utilization of international rivers for other purposes than navigation. UN Doc ST/LEG/SER B/12, p.376.

Vesilind, P. J. 1993. Water: The Middle East's critical resource. National Geographic, May 1993.

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Author information:

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Mr. Kaya is a Ph.D. candidate at the University of Keele, Department of Law, Staffordshire, ST5 5BG, United Kingdom. He can be reached for comment by email at

Additional web resources:

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Political map of the Middle East, 1997
( e_East_pol97.jpg)
This large (315K) map is from the Perry-Castaneda Library of the University of Texas at Austin. It shows Turkey, Syria, Iraq and the general course of the Euphrates and Tigris Rivers.

GAP Project
This site is part of the "Business & Economy" section of the Republic of Turkey web site, sponsored by the Government of Turkey. It provides extensive information on the project, from the Turkish point of view. [NB: as of publication date, the editor was not able to locate any Syrian- or Iraqi-sponsored web sites concerning the GAP Project.]

The Helsinki Rules on the Uses of the Waters of International Rivers
This on-line document, provided by the Turkish government, comprises the text of the 38 articles of the Helsinki Rules.

U.N. Convention on the Law of the Non-navigational Uses of International Watercourses
( This web site from the International Law Commission provides the text of the Convention, an analytical guide, and up-to-date information on the Convention's status (access to status information requires registration).

Southeastern Anatolian Project
This December 1996 paper was written by Sandra Akmansoy of the University of Texas at Austin. It provides an in-depth analysis and some strong conclusions concerning the underlying political nature of the conflict that the GAP project is causing among Turkey, Syria and Iraq.

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