Euphrates Turkey, in Syria and in Iraq. The same figures are given by Isaev and Mikhailova. The length of the Shatt al-Arab, which connects the Euphrates and the Tigris with the Persian Gulf, is given by various sources as . Both the Kara Su and the Murat Su rise northwest from Lake Van at elevations of and amsl, respectively. At the location of the Keban Dam, the two rivers, now combined into the Euphrates, have dropped to an elevation of amsl. From Keban to the Syrian–Turkish border, the river drops another over a distance of less than . Once the Euphrates
Euphrates and Iraq. Apart from the changes in the discharge regime of the river, the numerous dams and irrigation projects have also had other effects on the environment. The creation of reservoirs with large surfaces in countries with high average temperatures has led to increased evaporation; thereby reducing the total amount of water that is available for human use. Annual evaporation from reservoirs has been estimated at in Turkey, in Syria and in Iraq. Water quality in the Iraqi Euphrates is low because irrigation water tapped in Turkey and Syria flows back into the river, together with dissolved fertilizer chemicals used