Characteristics and behavior of the flow in hydraulic structures, a complex phenomenon that isimperative to use software that will beto be study.Gabiony stepped spillway is a simple hydraulicstructures to control erosion downstream of dams, and, depreciation of structures is used. Roughstairway consisting of overflow from the stairs near the crest of the weir is started and continues tohave a lower heel. Research shows that the rate of depreciation of energy in Spillways stairs of the flat(no stairs) has the same size . In this study, the ratio of width to length roughness (b / h) was equal to0.25 , 0.5 ,1 , and three-positions height roughness and three-state roughness height to flow 220, 4(lit/s). In the nine-step model with a height of stair 0.1 m and 21-degree slope was investigated Andthe roughness effect on the distribution of power and the creation of the vortex on the stairs of astepped spillway Gabyvny was down by Flow-3D software . This research showed rough results in theflow range 0.004 , 0.009 , 0.01(m^3/s) by the nappe regime to collapse and from flow 0.016 metersper second to the higher flow is a skmming flow regime. Most energy-related depreciation In the flow0.016 with 79.5 Percent Energy depreciate and Depreciation less energy to flow 0.22 (m^3/s) with20.4 Percent of energy is depreciate. پرونده مقاله