Inundation floodingmap aimedto find outearly warningsto avoidenvironmental damageandhumanin terms of theheight ofthe wave ofwater, speed time arrival, effects of inundation sideanddepth of the water/ distanceand reduce the impact of the flood wave after obtaining the process of collapse of the dam in the lower part of the river to the dam area. The study has been using a numerical model one-dimensional depends on the development of equations (Saint-Venant) so that parts of the river, any river channel main banks of the right and left treated as separate parts, that’s the difference in the characteristics of the hydraulic and engineering, along the line of the flow will take into account in each section of the sections and flow in the river valley. Throughapplied numerical model of the Nile River in the area between the Roseires dam and Khartoum is distance (630 km) south of Khartoum , to get a jest analysis of the impact of a wave of flooding in the river on the following parameters : the maximum discharge , the maximum of attributed, as underdevelopment of the discharge maximum , and the time defaults to the maximum level and the surface area on the banks of the river and its extension and different values of the coefficient of manning roughness to the banks of the river. Eight scenario have been prepared for the flood wave read to compare the effect amount of water flow in the channel resulting from the collapse of the dam was resulting of Roseires dam , eight scenario to represent the five and extract the resulting values of Inundation map to cities located on the downstream of the dam.Thefive scenarioswerecalculated by using (HEC-RAS 4.1.0), (HEC-GeoRAS)a GIS programs and the flood wave resulting from the collapse of the Roseires dam to compare the results showed that the scenario NO. 5 is the best scenario result from the collapse makes sense due to the form of the disposal of the flood wave resulting from the collapse of the Roseires dam and then get overtopping from Sennar dam to the inability of the reservoir and dam to stop the flood wave. The results also indicate that the time needed to reach the greatest discharge of the flood wave resulting from the collapse of the Roseires dam to the city of Khartoum is ( 4, 6, 7and 9 ) day on the cities ( Roseires , Sennar , Wad Medani and Khartoum ) respectively, of the cases . The maximum height of the flood wave reaching the city of Khartoum has given the scenario NO. 5 by height wave (3-50) meters respectively. As well as the delay in the arrival time of the maximum height of the flood wave to the city of Khartoum is one day for the five scenarios compared to the other. The Inundation map development resulting from the collapse of the Roseires dam and get the flow overtopping the Sennar dam, arrival to Khartoum, was determined the surface area of the affected river and both banks of the depth of the wave and latency along the river has been selected four major cities along the river which Roseires,Sennar, Wad Medani and Khartoum.