The dynamic response of estuaries to sea-level rise and implications for tidal wetlands

Sea-level rise (SLR) will alter hydrodynamic properties inside estuaries, and affect tidal wetlands, such as mangrove and saltmarsh, located within estuaries. A relationship has been established between hydrodynamics and intertidal wetlands in some creeks and estuaries, but few studies have jointly assessed the impacts of SLR on hydrodynamics and wetlands at the scale of an estuary. This may cause misleading projections of responses in estuarine hydrodynamics and intertidal wetlands to SLR because interactions between the two are not considered. Intertidal wetlands will adapt to SLR and alterations in estuarine hydrodynamics through vertical accretion of substrates and lateral adjustment in the distribution of wetlands, which may affect the hydrodynamics of an estuarine system. The overall aim of this study was to develop a coupled eco-morphodynamic modelling approach that addresses interactions between estuarine hydrodynamics and intertidal wetland morphodynamics, and incorporates processes influencing wetland geomorphological change in the context of SLR. This was achieved by establishing relationships between field observations of water level, tidal velocity and wetland inundation in the mature Minnamurra River barrier estuary located in southeast Australia; quantification of mangrove and saltmarsh inundation regimes across Minnamurra and Clyde River estuaries; and coupled eco-morphodynamic modelling of hydrodynamics and wetlands under SLR at Minnamurra River estuary.