Stage–discharge prediction for meandering channels

Abstract

Accurate estimation of discharge in any open channel depends on the suitable accounting of the resistance coeffi cients. The energy loss is infl uenced by the channel geometry and fl ow parameters, which are assumed to be lumped into a single value manifested in the form of resistance coeffi cients in terms of Manning's n, Chezy's C, and Darcy–Weisbach f. The fl ow structure for meandering channels is more complex as compared to that of straight channels due to its three-dimensional motion. Consequently, the use of design methods based on straight channels is inappropriate when applied to meandering channels and results in large errors when estimating the discharge. A series of experimental results are presented concerning stage–discharge–resistance relationships for meandering channels with rigid and smooth boundaries. Investigation concerning the loss of energy of fl for meandering channels in terms of variation of Chezy's C due to variation of sinuosity, geometry, and longitudinal slope are studied. A discharge predictive method for meandering channel is proposed that accounts for the variation of roughness with depth of flin the channel. The performance of the model is evaluated and is found to compare well with other available models.