Transport rate and bed profile computations for clay–silt–gravel mixture

Identification of parameters governing sediment transport is important, as its understanding can greatly assist in resolving the issues caused by sediment transport in the riverine system. This paper presents the results of an experimental study for the computation of bed load transport rate and suspended load transport rate along with transient bed profile for a cohesive mixture of clay–silt–gravel in which clay varied from 10 to 50% on weight basis. The transport rate of sediment is found to be higher in the initial period of time, however, it decreases with passage of time. Transport rate of sediment decreases with the increase in clay content, while it increases with excess shear stress. Bed degradation was found to be higher in upstream section than that of downstream section. Clay content affects the bed degradation profile as well as equilibrium time. Equilibrium time is found to be increased with clay content. The main parameters affecting the detachment and transport of sediment from cohesive bed are clay content, excess shear stress, and equilibrium time. Relationships have been developed for the computation of bed load transport rate, suspended load transport rate, and transient bed profile along with the auxiliary relationships for initial transport rate of sediment, equilibrium time and maximum degradation. All the developed relationships were found to be in good agreement with the observed ones.