Evaluation of the equations for concentration distribution of suspended sediment in open channels

Knowledge of the suspended sediment distribution is important for calculating suspended load in streams and rivers, because in the large depth flows, the suspended load comprises up to about 80% of the total load. Until now, many equations have been proposed by researchers for estimating the suspended sediment distribution in open channels. In this study, these equations have been assessed and the best equation has been selected among 9 empirical equations by using statistical analysis. For this purpose, the most reliable experimental data have been used. The results showed that among considered equations, the Einstein and Chien’s equation (developed in 1952) had the most agreement with the experimental data (RMSE=0.048, R2=0.988, EF=0.988, and ME=0.086) and presented the most accurate estimation of suspended sediment distribution. Inversely, the results showed that the McTigue’s equation (developed in 1981) and Willis’s equation (developed in 1988) had the least accuracy and don’t recommend using them for estimating the suspended sediment distribution in open channels.