Variation of Jebel Aulia Reservoir levels along White Nile River causes wider variation of the wetted area. This adds to the challenges for the pumping water for irrigation. Historically, there was always the tendency to maintain high reservoir levels in favor of the upstream pumping stations. The aim of this study is to assess possible impacts of changing the operation rules of Jebel Aulia Reservoir. Water balance approach has been applied to investigate the existing and three modified operation policy. The evaluated parameters include duration of high reservoir levels preferred by pumping schemes, satisfaction of downstream water demands and area of flood plain agriculture (Guroof), evaporation and hydropower generation. Scenario 2 was found to be the best in obtaining high reservoir level and given the highest annual hydropower production. Scenario 3 was found to be the best in terms of evaporation losses and the downstream demands.