A river of the Middle East, 2780 kms long which rises in the Kurdish area of Turkey, flows into the Arab/Persian Gulf after crossing Syria and Iraq successively and forms with the Tigris, in the latter country, the Shatt-El-Arab. Its average annual flow in Iraq is 32 billion m³ but like the Tigris, its flow is very irregular: 53% of its waters flow during the three months from April to June.

Before the last few decades, Iraq was the main user of the waters of the Euphrates, 88% of which come from the river basin in Turkey. Recently Syria and especially Turkey have both developed major projects for the use of these waters without any sharing-out agreement between the three countries.

Because there is no agreement, international precedent suggests that in cases of the use the waters of a river upstream, this country cannot appropriate more than 50% of the flow measured at the point of entry to the country located downstream.

Turkey announced that it would be limiting the flow of the river from 1 January 1990, the date when filling the Ataturk reservoir was due to start, but guaranteed a flow of 500 m³/second, or 15.75 billion m³ per year, which is a source of much tension between the countries in question.

The same situation was created between Baghdad and Damas at the beginning of the Seventies during the construction of the Tabqa reservoir in Syria: this country, which used about three billion m³ of water from the Euphrates per year will no doubt need double that amount at the beginning of the next millennium.