Sediment Dynamics of the Snowy River Estuary Entrance

Entrance conditions for barrier estuaries can be highly dynamic, with fluvial fluxes, tidal flows and coastal storms all influencing the system morphodynamics. To gain an understanding of the relative impact of these forcing factors on entrance conditions for the Snowy River estuary, a detailed hydrodynamic and sediment transport model has been developed. Recent field monitoring has provided flow and level information throughout the estuary, covering periods of low river inflow and also flood flow conditions and this has enabled the model to assess how the tidal channel responds over a range of fluvial flows. Criteria have been developed to ascertain trigger levels for potential closure of estuary entrance and river flow requirements to reduce the likelihood of closure. It has also been shown that the hydraulic roughness through the channel under differing flow regimes impacts upon the rate of sediment deposition and erosion and increases the complexity of long term morphological simulations.