Laboratory investigation of incipient motion of non-cohesive and non-uniform sediment in irrigation and drainage Channels

Sediment control on water distribution and transmission networks has a lot of importance. Sediment input to the channel, is deposited in different parts of transmission and distribution network and reduced capacity of current carrying. And which increases the cost of maintenance and dredging operation will be followed. Cohesive sediment due to dissolving properties and low weight has a little capacity for deposition. There is a major problem caused by non-cohesive sediment which is more possibility for deposition. A lot of research has been recently done to determine the conditions of incipient motion velocity of uniform and non-cohesive sediment in open channels and many Relationships or graphs are presented. But studies on non-cohesive and non-uniform sediments are very little. With regard to the channel sediments are mostly non-uniform, Determination of the flow rate for prevent of sediment deposition can be a effective role in increasing of transmission efficiency and which reduced costs. In this study, incipient motion of non-cohesive and non-uniform sediment was investigated by physical modeling and dimensional analysis. In this study 9 non-cohesive and non-uniform sediment has been tested with different dimensions and uniformity coefficient in 0.0005, 0.001and 0.002 slopes. Results showed that by increasing the slope and particle size parameters, decrease stability parameter and stability parameter, will increase with increasing uniformity coefficient.