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
Euphrates enters the Upper Mesopotamian plains, its grade drops significantly; within Syria the river falls while over the last stretch between Hīt and the Shatt al-Arab the river drops only . The Euphrates receives most of its water in the form of rainfall and melting snow, resulting in peak volumes during the months April through May. Discharge in these two months accounts for 36 percent of the total annual discharge of the Euphrates, or even 60–70 percent according to one source, while low runoff occurs in summer and autumn. The average natural annual flow of the Euphrates has been determined from