MODELLING THE MEDIUM TERM MORPHODYNAMIC RESPONSE OF A TIDAL COASTAL INLET USING LOGICAL NETWORKS

摘要

Coastal and estuarine morphodynamic behaviour is complex because of the feedbacks between sediment transport, hydrodynamic forces and morphology. A simplified model that represents a geomorphic system as a set of linked nodes has been used to analyse the morphodynamic evolution of a tidal inlet and associated ebb delta. In earlier logical network modelling, model variables were restricted to take one of only two values. Here we investigate a discrete extension of this that permits variables to take on fractional values, thereby enabling an improved description of states within the system. The new approach captures the same morphodynamic behaviour as the simpler model (stable states, cycles), while also identifying some additional intermediate states. The interpretation of the new states is not straightforward and a thorough understanding is likely to require a reworking of the mapping of ‘morphological rules’ on to the logical equations that govern the system morphodynamics. Practical application to real systems will also require an extended set of components and the simulation of larger logical networks.