The Khuzestan plateau is a fertile region with great water reserves. Karun River which is the largest river in the country and provides the largest water resource runs through Khuzestan and ultimately runs into Arvand River in the Arvand Free Zone. AFZ also benefits from the water provided by the smaller Arvand River and Bahmanshir which make the region extremely rich in water resource.
Karun is probably the greatest river in Iran and much of Khuzestan’s fertile land is a result of this river. Running 890 kilometers long, about 750 square meters of water per year is extracted. It provides over 23652 million square meters. It has a flow of 3000 square meters per second and at average between 1200 to 1800 square meters per second. Karun is divided into two major branches after entering Arvand Free Zone. One is a man-made canal called the Zhian canal and the other is the Bahmanshir River.
Bahmanshir is the largest branch of Karun and it cuts off Karun in the northern section of the Abadan Island.