AbstractEntrance jetties and training walls have instigated fundamental perturbations to coastal and estuary processes at several locations on the Australian eastern seaboard inducing long term changes to foreshore alignments, tidal current velocities, tidal plane elevations and marine ecologies with significant consequences, some having been realised only recently. This paper presents examples of long-term impacts of entrance jetties and training walls on coastal and estuary processes, gleaned from experience on the NSW coast. Jetties constructed at estuary entrances have the potential to alter fundamental coastal and estuary processes inducing changes that evidence indicates may take centuries to resolve. While many beneficial and adverse impacts of jetty construction have been known for many years, such as the improvements to navigation and flood mitigation from rainfall runoff and the interruption to littoral drift transport causing down-drift erosion, some impacts of jetties and training walls have not been well understood.
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