The Sennar Dam is a dam on the Blue Nile near the town of Sennar, Sudan. It was completed during the 1920s by the British contractor, S Pearson & Sons, Ltd, to a design by engineer Sir Murdoch MacDonald. 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.
Work on the dam first started in 1914, but was almost immediately interrupted by the outbreak of World War One. Work re-commenced in 1919, the contractors being the Sudan Construction Company, who carried on the work until 1921 when work was stopped for a second time as it became clear that the estimated cost of the scheme would be considerably exceeded.
In 1922, with further funds obtained, six British firms were invited to submit tenders to complete the dam and to build the connecting canal system. S. Pearson & Sons, Ltd, of London, was successful, and contracted to complete the dam by July 1925. Work began in December 1922, and the dam was finished in May 1925 (John Watson Gibson was Pearson's site agent). Oswald Longstaff Prowde was resident engineer on the dam, which was designed by Sir Murdoch MacDonald. Both later became partners in Sir M MacDonald & Partners.
Coordinates: 13°32′50″N 33°38′07″E / 13.54722°N 33.63528°E