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
Castlereagh River travel the distance, and up to 47 hours. Usually in peak floods, the greater the water volume, the faster the travel times of the peak. However, the flattening of the terrain upstream of Coonamble results in decreased flow velocity (but means a greater area for the flow is needed to avoid flooding). It is not correct that the Castlereagh River is an underground river (subterranean river) or an 'upside down' river. However, water that once was in the river bed on the surface does flow through the extensive sands under the riverbed. This water is therefore part of the underground