New Deal On The Nile: The Gezira Cotton Scheme -- Nerve-centre of the million acre Gezira cotton growing scheme the two mile long Sennar Dam on the Blue Nile, which feeds the complex canal system for the irrigation of the Gezira.The British Government in Africa has long had its own 'Tennessee Valley' scheme the Gezira Cotton Scheme in the Valley area of nearly a million acres between the Blue and White Niles. Plans for the area's development were begun before the last war, and by 1925 the Sennar Dam, two miles long and over a hundred foot high at its deepest point, was completed. September 6, 1951. (Photo by British Official Photograph).