Since it is an accepted practice to have knowledge of flood hazard potential and possible emergency action plans in case of probable dam breaches (single or cascade) to downstream communities whose livelihood is dependent on the Nile River, this Special Study by the Civil Engineering Division of Addis Ababa University was commissioned by ENTRO to identify, analyze, and assess impacts of dam breach in the Blue Nile cascade using appropriate modeling tools. This study covered the GERD, Rosaries and Sennar dams in the Blue Nile sub-basin.