The Bahr Yussef( )(Arabic: بحر يوسف), which roughly translates frae Arabic as "the waterway o Joseph", is a canal which connects the Nile River wi Faiyum in Egyp. This wis oreeginally in prehistoric times a natural affshuit o the Nile which creatit a lake tae the wast durin heich floods. Beginnin wi the 12t dynasty, the waterway wis enlairged an the Fayyum wis developed tae enlairge Lake Moeris. The canal wis built intae the natural incline o the valley, creatin a channel 15 km lang an 5 m deep that sloped intae the Fayyum depression. The canal wis controlled bi the Ha-Uar Dam, which wis actually twa dams that regulatit the flow intae the lake an oot o the Nile. As the surroondin aurie chyngit at aboot 230 BC, the Bahr Yussef eventually became neglectit, leavin maist o Lake Moeris tae dry up creatin the depression that exists the day an the modren province o Al Fayyum.
The Bahr Yussef still exists the day, feedin water northwards intae the Birket Qarun, parallel wi the Nile.