I filmed this video during my visit to Jebel Aulia dam in October 2018. The dam was built in 1937 by the British across the White Nile to avoid the Nile flood. The dam is located 45 km from Khartoum.
The fish ladder shown in the video is located along the eastern side of the dam. Regardless the effectiveness of the fish ladder, typically ladders (passes) are constructed to help Nile fish undergo pronounced migrations up and down the river, probably for purpose of breeding.