experimental modeling hydraculicallydam breaks considering flash flood event

abstract although many studies have been carried out about dam break, this phenomenon still is one of the most important issues in the field of hydraulic engineering due to its hazards to human societies. predicting the critical conditions including coincidence of flooding and dam break indicates more field studies requirement. in this research the mutual effects of coincidence of negative surge due to dam break and flash flood has been studied using under different stored water levels. in addition, the effects of bed slope, existence of reservoir sediment and different initial reservoir depth have also been studied. due to unsteady condition of flow, the stereoscopy method was employed to measure the hydraulic parameters such as depth. using two digital cameras, results showed that by increasing the initial depth in dam's reservoir and channel slope, the reservoir would evacuate faster. furthermore, sediments in which act like step in the flow direction can cause an increase in speed of the positive surge toward downstream. in addition by increasing the maximum of flow rate and base time of hydrographs, water rise in downstream was monitored as well.