Known as the Abbai in its country of origin, this river has its source near Lake Tana.
This waterway winds around the Choke Mountains before flowing through the Gezira Plain while its source is on Mount Gishe. Among its tributaries are the Dinder and Rahad rivers and the flow of this river is stopped by the Roseires and Sennar dams. Pedro Paez was the first European to find its source, although John Bermudez first described its Tis Issat Falls. Known as the Abbai in its country of origin, this river has its source near Lake Tana. For 10 points, name this river which begins in Ethiopia before joining with the "White" branch in Khartoum to form the longest river in the world.
This waterway winds around the Choke Mountains before flowing through the Gezira Plain while its source is on Mount Gishe.
{Blue Nile} [or an-Nil al-Azraq; accept Abbai before read]