Course
It originates in the Zagros Mountains of western Iran, on the slopes of 14,921-foot (4,548 m) Zard-Kuh. The river flows south and west through several prominent mountain ridges, and receives additional water from the Vanak on the south bank and the Bazuft on the north. These tributaries add to the catchment of the river above the Karun-4 Dam. Downstream 25 kilometres (16 mi), the Karun widens into the reservoir formed by the Karun-3 Dam. The Khersan flows into an arm of the reservoir from the southeast. The river passes through this reservoir and flows through a narrow canyon, now in a northwest direction, past Izeh, eventually winding into the Sussan Plain. The Karun then turns north into the reservoir of Shahid Abbaspour Dam (Karun-1), which floods the river's defile to the southwest. The Karun flows southwest into the impoundment of Masjed Soleyman Dam, then turns northwest. Finally, it leaves the foothills and flows south past Shushtar and its confluence with the Dez. It then bends southwest and bisects the city of Ahvaz, and south through farmland to its mouth on the Shatt Al-Arab river at Khorramshahr, where its water, together with that of the Tigris and Euphrates, turns sharply southwest to flow to the Persian Gulf.
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