ABSTRACT
A depth-averaged model using a finite-element method has been adopted to calculate bed deformation in alluvial curved channels. The model system consists of an unsteady hydrodynamic and a sediment transport module. The hydrodynamic module is based on the two-dimensional shallow water equations. The sediment transport module comprises a semi-empirical model of non-equilibrium bed load. The model developed for a 10 km meander reach has been validated, inter alia, by computing the lateral water level and the bed deformation after two years. The predictions of the model are presented in which the bed deformation is calculated in curved alluvial channels under steady and unsteady flow conditions. A comparison of bed evolution and depth-averaged flow velocities with the 3 -D version of the finite-element model showed generally good agreement. The simulations are also compared with data from in situ measurements, e.g. the mean fraction diameter by freeze cores and 3 -D velocity measurements.
