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
Nossob River flow about once a century. However, water does flow underground to provide life for grass and camelthorn trees growing in the river bed. The Nossob may flow briefly after large thunderstorms, causing wildlife to flock to the river. The Nossob ends at a confluence with the Molopo River some 50 km south of Twee Rivieren. The confluence at is still 890m above sea level. The Molopo is in turn a tributary of the Orange River, which it meets downstream of Augrabies Falls. Important dams in the basin, both on the Oanob River, a tributary of the Auob: Nossob River The