Sediment resuspension within a microtidal estuary/embayment and the implication to channel management

Abstract

Sediment transport patterns within coastal environments continue to be of strong concern to the coastal engineer, scientist and manager. A study was conducted on Saltwater Creek, Gold Coast, Australia, which is a small microtidal estuary/embayment system that has no continual inflow of freshwater with inflows only resulting from direct catchment rainfall. Use was made of an Acoustic Doppler Current Profiler (ADCP) and a profiling transmissometer to determine the likelihood of tidal flow induced resuspension. Results showed that the apparently simple system was actually highly complex in nature. It was susceptible to significant sediment loadings as the result of catchment runoff and biological activity. Resuspension activity within the main channel was qualified and found to play only a minor role in the observed suspended sediment loadings. The results obtained have permitted the development of a conceptual model, from which some future management strategies can be proposed. Importantly, the techniques used in this study can be applied elsewhere to investigate sediment transport (including resuspension) properties when equipment resources are limited.