Author(s): A. F. Nielsen; A. D. Gordon
Linked Author(s):
Keywords: Estuary; Stability; Escoffier; Entrance; Breakwaters
Abstract: Data and theory show that several large estuaries in New South Wales that were thought to be stable after having been modified by entrance breakwaters are, in fact, unstable and have been scouring for decades as a result of the breakwater construction. Research shows that this trend may well continue for centuries before the entrances achieve stable hydraulic regimes. Implications have included the requirements for on-going extensive bank erosion protection works along channels, reconstruction of bridge pier foundations and permanent changes to fringing ecologies, none of which previously had been anticipated. Analysis of available time series of amplitude and phase of tidal constituents has provided signatures that, along with established estuary stability theories, allow for an informed assessment of the future course of the scouring action and the timeframes to reach stable equilibrium. The research also provides a cautionary tale for future entrance training projects.
Year: 2011