Agriculture in Syria runoff most of the year. The river flows southeastward across the arid Syrian Plateau into Iraq, where it joins the Tigris River shortly before emptying into the Persian Gulf. In addition to Syria, both Turkey and Iraq use dams on the Euphrates for hydroelectric power, water control, storage, and irrigation. In the mid-1980s, about a half of the annual Euphrates River flow was used by these three countries. Syrians have long used the Euphrates for irrigation, but, because the major systems were destroyed centuries ago, they now make only limited use of the river's flow. In the mid-1980s, the Euphrates
Water supply and sanitation in Iraq of Iraq. These two rivers account for 98% of Iraq`s surface water supply. Their flow is therefore very vulnerable to dams and water diversions in Turkey, Syria and Iran. The Euphrates does not receive water from permanent tributaries within Iraq territory and is fed only by seasonal runoff from wadis. The average annual flow of the Euphrates at the border to Turkey is estimated at 30 km³, with a fluctual annual value ranging from 10 to 40 km³. The Tigris has an average annual runoff of 21.2 km³. Within Iraq, the Tigris River receives water from five main tributaries, namely