Iraq has diverse geography that falls into four main regions: desert west of the Euphrates, Upper Mesopotamia between the Tigris and Euphrates rivers, northern Kurdish highlands, and lower Mesopotamia extending to the Persian Gulf. The Tigris and Euphrates rivers flow from Turkey through Iraq and meet north of the Persian Gulf to form the Shatt al-Arab river. Iraq has built dams on the rivers for irrigation and flood control but this reduces downstream water availability, causing conflict with Turkey. The government has also drained marshes, displacing populations and threatening wildlife but development depends on agreements with Turkey over water.