Risk Frontiers – in association with the Marine Climate Risk Group at Macquarie University – have delivered a modelling study for NSW Office of Environment and Heritage, as part of the NSW Adaptation Research Hub, to help understand the long-term stability of the NSW coast. As beaches respond to rising sea levels an offshore transport of sand is generally expected (leading to erosion) – but an onshore supply from deep water has the potential to offset some of the impacts of sea-level rise. The rate of sand supply to the NSW coast from deep water is a major uncertainty in projecting future coastal response to sea-level rise.
This work used a combination of wave, hydrodynamic and sediment transport modelling to look at sand supply rates over long time-scales (decades to millennia). Modelling suggests that over these time-scales, sand is being transported from water depths of up to 40 m – much deeper than is currently accounted for in coastal engineering studies.
This may have implications for coastal management over the long-term, including how we nourish beaches with sand from offshore sources.
Risk Frontiers operate a suite of wave, flow and transport models to model a range of hazards in the coastal zone – and develop solutions to managing their impacts.