Accuracy of Sediment Flux Computations in Tidally Driven Simulations

Abstract

Tidal asymmetry, generated by nonlinear shallow water processes, controls to a large extent the long-term fate of noncohesive sediments in estuaries and lagoons. Since the accurate reproduction of this asymmetry is still a challenge for hydrodynamic models, it is important to quantify the effect of errors in the representation of tidal asymmetry on tidally averaged sediment fluxes. The effect of the accuracy in the amplitude and phase in the tidal velocity on the errors in the evaluation of residual sediment transport was analyzed analytically. Results show that errors of the order of 20% in velocity amplitude can lead to sediment transport errors on the order of 100%. Phase errors lead to smaller, but non-negligible, errors in sediment transport. Simple expressions to estimate these errors are provided.