The Bahmanshir channel is a secondary estuary of the Karun River that parallels the Arvand Rud/Shatt al-Arab waterway on the far side of the Abadan Island for 70 miles, emptying into the Persian Gulf. The Bahamanshir served as the main estuary of the Karun River before the digging of the Haffar canal by the DaylamiteBuwayhid king Panah Khusraw Adud ad-Dawlah, that joined the Karun to the Arvand Rud / Shatt al-Arab waterway at the site of the present-day Khorramshahr. The Haffar in time became the main estuary of the Karun, relegating the Bahmanshir to a secondary estuary status.