عنوان مقاله [English]
The coarser particles deposit gradually and form a delta at the upstream of the reservoir that extends further downstream towards the dam. In this research the effect of non-uniform sediment particles has been studied experimentally on the Delta progression in the reservoir. 10 types of grading curves were used. All of the curves were the same in mean diameter and they have normal distribution. In this research, the effect of non-uniform particles on delta progression was investigated using a physical model. In this model the river is connected to the reservoir by a gradual transition. Based on the experimental observations, in the range of this study velocity of Delta progression decreased with increasing of non-uniform particle and time of progression increased. In the range of geometric standard deviation 1 to 2 the effect of non-uniform particle was not tangible but with increasing of geometric standard deviation the effect of non-uniform particle on Delta progression observed. Based on the experimental observations, slope of foreset decreased with increasing of non-uniform particle.