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
Cordes (river) Cordes (river) Cordes () was a small stream of Mesopotamia which rose in the Mons Masius, and was a tributary of the Chaboras, itself a tributary of the Euphrates. The town of Dara was situated upon its banks. Justinian's engineers diverted the river towards the city by digging a canal. The river now flowed through the city, ensuring ample water supply. At the same time, by means of diverting its flow to an underground channel which exited to the north, Dara's garrison was able to deny water to a besieging enemy, a fact which saved the city on several occasions.