An investigation of the presence of low-dimensional chaotic behaviour in the sediment transport phenomenon

Abstract

Understanding the dynamics of the various components (and the mechanisms involved) in a river system and establishing precise relationships between them are important for an accurate description of the sediment transport phenomenon. Despite the significant progress achieved in the last century with the development of a variety of approaches, there is no generally accepted simple relationship between the components. A preliminary attempt is made herein to address the sediment transport problem from a low-dimensional chaotic dynamical perspective. Such an approach assumes that the seemingly complex behaviour of the sediment transport phenomenon can be the outcome of a simple deterministic system influenced by a few dominant nonlinear interdependent variables sensitive to initial conditions. As a first step towards assessing the validity of such a hypothesis, the dynamical behaviours of three important (and related) components of the sediment transport phenomenon, i.e. water discharge, suspended sediment concentration and bed load, in the Mississippi River basin (at St Louis, Missouri), USA are studied. The correlation dimension method is employed to identify the dynamical behaviour (chaotic or stochastic). The results indicate that the three components exhibit low-dimensional chaotic behaviour. A possible implication of such results could be that the complete sediment transport phenomenon might also exhibit low-dimensional chaotic behaviour. Efforts towards analysing the other components of the sediment transport system and establishing relationships between them are underway.