Analysis of Alluvial Channels Stability based on Empirical and Analytical Methods

It is still a concern of both hydraulic engineers and geomorphologists to improve prediction of the channel geometry and probable bedform so that it could convey the discharge and its accompanying sediment load channel without significant changes on geometry and planform during their design life. Due to the complexity and dynamic nature of the alluvial system، empirical، semi-empirical and statistical models with their inherent limitation in application were developed for designing regime channel and predicting channel dimensions and slope. In this research، mathematical model of GSTARS4. 0 was used to predict the stable channel geometry، employing maximization sediment transport hypothesis of White et al، Brownlie and Van rijn. The outcome results of model were compared with the experimental data and those were calculated from empirical equations. It was generally found that the minimum stream power hypothesis used in GSTARS4. 0 model predicted the regime channel geometry more accurate than other methods for width and depth ratios of 0. 95 and 1. The sediment concentration obtained from Brownlie equation shows a better compatibility with the available experimental data to compare with other methods mentioned.