A model for predicting the lateral distribution of sediment transport in river bends

Distribution of lateral velocity and suspended sediment concentration in river bends is highly non-uniform. Predicting such velocity and sediment distributions is prerequisite for many applications, such as river bank protection, sediment transport, deposition pattern, pollutant transport and flood control. Due to secondary flow development, flow structure in river bends has three-dimensional feature. In this case, one-dimensional mathematical models are generally not suitable, so two- or three-dimensional mathematical models have to be used. In this paper, field measurement of lateral distributions of flow velocity and suspended sediment concentration was conducted in three bends at the Karun River in Iran (namely, Jangieh, Khabineh and Malheh), and the measured velocity data were used for calibrating the Spooner and Shiono model. Based on the lateral velocity distributions by this mathematical model, sediment transport capacities were computed using five commonly used empirical formulas of sediment transport. The results showed that in the three river bends, the sediment transports formula by Yang agrees well with the measured lateral sediment concentration. The Van Rijn formula also predicts the results with suitable accuracy. The other three formulas by Ackers-White, Engelund-Hansen, and Karim-Kennedy significantly over-predict the sediment concentration compared with the measured data.