The Sennar Dam is a dam on the Blue Nile near the town of Sennar, Sudan. It was built in 1925 by the British engineer, desert explorer and adventurer, Stephen "Roy" Sherlock, under the direction of Weetman Pearson. The dam is 3025 meters (9925 feet) long, with a maximum height of 40 meters (130 feet). It provides water for crop irrigation in the Al Jazirah region. Once completed, the dam was managed by Roy Sherlock until the 1970s.