Concept:The Gezira Scheme is an irrigation project in Sudan, supplied by dams that serve its canal system.Explanation:Sennar Dam is well known as a main source of water for the Gezira irrigation area.The Aswan Dam is located on the Nile in Egypt, far away from Sudan and the Gezira Scheme.Water from the Aswan Dam cannot supply the Gezira fields.Therefore, among the dams listed, the one used in the Gezira Scheme is not Aswan.So the dam which is not used in Gezira is Aswan.Answer:Aswan