Using Lagrangian coherent structures to investigate tidal transport barriers in Moreton Bay, Queensland

Horizontal chaotic dispersion plays an important role in the distribution and fate of pollutants in coastal waters. Particle dispersion within coastal areas is governed by the combination of local weather events and the interaction of the flow field with local morphological structures, at small and large time scales. The present study investigates the horizontal dispersion and barriers to material transport in a tidal dominated estuary (Moreton Bay) using a combination of a hydrodynamic model and the identification of Lagrangian Coherent Structures (LCS) which acts as transport barriers. In this study, Finite-Time Lyapunov Exponent (FTLE) method has been applied to investigate how the material gets close to the LCS and also to identify the characteristics of the LCS for spring and neap tides