Tigris–Euphrates river system border. Since the 1960s and in the 1970s, when Turkey began the GAP project in earnest, water disputes have regularly occurred in addition to the associated dam's effects on the environment. In addition, Syrian and Iranian dam construction has also contributed to political tension within the basin, particularly during drought. The general climate of the region is subtropical, hot and arid. At the northern end of the Persian Gulf is the vast floodplain of the Euphrates, Tigris, and Karun Rivers, featuring huge permanent lakes, marshes, and forest. The aquatic vegetation includes reeds, rushes, and papyrus, which support numerous species. Areas
Sajur River join the Euphrates on Syrian soil – the other two being the Balikh and the Khabur. The Sājūr is also the only river in Syria that enters the Euphrates on its right bank; both the Balikh and the Khabur flow into the Euphrates on the left bank. The Sājūr drains a total area of . The Syrian part of the Sājūr basin – the Manbij Plain – has been particularly well-studied. This area is bounded on the north by the Syro–Turkish border and extends as far south as Manbij. To the west, the Manbij Plain is bordered by basalt outcrops;