All of the coastal hazards listed above can pose risks to our coast. Beach erosion, cyclic variability and shoreline recession are key hazards that affect the open coast of the Byron Shire coastline.
The actual amount of beach erosion and/or inundation that occurs during a storm is difficult to predict due to the complex interaction of many factors, including the following.
- Beach state controls the natural rate that a beach tends to respond to storms.
- Dune height and beach width determines the amount of sand available to initially buffer the erosion impact on the dunes and the amount of freeboard that might exist as the storm water level rises and reaches its peak.
- Storm wave height, period, and duration determines the rate at which erosion occurs and how long the erosion proceeds, and therefore the total volume of sand removed from the beach.
- Water level determines the height that waves can reach to overtop natural and built structures, and the depth of inundation behind the shoreline.
- Time since the previous storm determines whether the current storm will be compounding the sand losses of a previous storm or sequence of storms;
- Localised processes include processes like rip currents that can locally enhance the beach erosion.
During 2020/21, the embayment’s coastline between Clarkes and Main Beach experienced persistent erosion due to a natural cycle of reduced sand supply around Cape Byron and storm waves coinciding with higher-than-normal tides. This resulted in loss of significant volumes of sand and dune vegetation. To learn more, see our project page: Main and Clarkes Beach Dune Recovery Project.