Analysis of initiation of sediment suspension from bed load

A theoretical analysis of the initiation of sediment suspension is performe d based on the concept of probability of suspension. The proposed condition for the initiation of sediment suspension from the top of the bed-load lay er is comparable with most existing empirical relationships for large parti cle Reynolds numbers. The study shows that a constant Rouse parameter can b e used as the critical condition for sediment suspension only for large dim ensionless particle diameters. When the probability of suspension is taken to be an infinitesimal value (P = 10(-7)), the derived relationship of the Shields parameter and the particle Reynolds number is in good agreement wit h the updated Shields diagram.