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
Kern River of the Central Valley Project, joins the river about west of downtown Bakersfield. The Kern River is one of the very few rivers in the Central Valley which does not contribute water to the Central Valley Project (CVP). However, water from the CVP, mainly the Friant-Kern Canal, will be deposited for water storage in the aquifers. Historically, the river flowed an additional south through a now-dry distributary to Arvin, where it formed the seasonal Kern Lake, which would grow to cover about during wet periods. Water from Kern Lake would then flow west through Buena Vista Slough into Lake Buena