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
Whiteadder Water and Berwickshire, with water. From there, crossing into Berwickshire it runs alongside the B6355 road to Ellemford where it joins the Dye Water and further on at Abbey St. Bathans, the Monynut Water. By this point having become a much larger body of flow, the Whiteadder meanders across Eastern parts of the Merse passing the communities of Preston, Chirnside, Allanton. Here at Allanton the Whiteadder joins with its antonymic counterpart the Blackadder Water. The river proceeds by Foulden, Edrington, and Paxton, it crosses into England, before joining the River Tweed, just north of East Ord, a suburb of Berwick-upon-Tweed. The