Tigris–Euphrates river system through the central plain and combine at Al-Qurnah to form the Shatt al-Arab and discharge into the Persian Gulf. The region has historical importance as part of the Fertile Crescent region, in which civilization is believed to have first emerged. The ecoregion is characterized by two large rivers, the Tigris and Euphrates. The rivers have several small tributaries which feed into the system from shallow freshwater lakes, swamps, and marshes, all surrounded by desert. The hydrology of these vast marshes is extremely important to the ecology of the entire upper Persian Gulf. Historically, the area is known as Mesopotamia. As
Operation Euphrates Shield that they had captured the village. Before clashing with the SDF, the FSA had captured half a dozen villages. On early 25 August, more than 20 Turkish tanks crossed into the Syrian border. The U.S. foreign minister later informed his Turkish counterpart that the YPG had started withdrawing to the east of the Euphrates river. A spokesman for Operation Inherent Resolve later announced that the SDF had withdrawn across the Euphrates river in order to prepare for the Raqqa campaign. The YPG later separately announced it had withdrawn to the east of Euphrates and said all military command along with