The overtopping phenomenon is the most common cause of embankment dams failure; and it contains a complicate process. Hence, its experimental investigation will be important. To study the hydraulic outcomes, the physical modeling of the mentioned phenomenon was performed at Hydraulic laboratory of Iranian water research institute. The results were analyzed in three stages: initiation, development, and the end which the breach moment of impermeable core is the boundary between initiation and development stages. Moreover, the development stage includes maximum breach geometry variations; peak discharge occurrence; and major sedimentation in the channel bed. When sedimentation pattern was drawn, the volume and the mass of eroded material were calculated. Also, the sediment thickness decreases moving downstream. Because of digging of the primary breach channel in the crest middle; the relatively-symmetrical sedimentation pattern and breach geometry were observed. The simultaneous measurements of breach geometry, flow hydrograph, and final sedimentation pattern are the unique achievements of the current research. The current research results make a new insight to manage the dam breach flow