RFI - PA2906-Coastal Hazard Assessment-R2 · MCU21/0212

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6.1.4       Dune Scarp Component
The methodology for calculating the erosion prone area includes an allowance for slumping of the frontal
dune following a short-term erosion event.

The angle of repose for dry sand is 35o and this has been used to determine the dune scarp component of
the erosion prone area. The short-term erosion calculations shown in Figure 16 and Table 5 indicate a
dune scarp of approximately 2 metre and this would result in erosion due to slumping of approximately 4
metres.

6.1.5       Summary of the Erosion Prone Area Reassessment
The erosion prone area reassessment for this appeal has been undertaken in accordance with the
Department of Environment and Heritage Protection (2013) requirements with a planning period of 100
years to accommodate the asset lifespan of the proposed house. We have also considered the effect of
shoreline recession due to 0.8 metres of sea level rise, short-term erosion associated with a 100-year ARI
storm event and dune scarp recession.

The site-specific erosion prone area calculated for the site is 91 metres measured from the seaward toe of
the frontal dune. The components of the erosion prone area for 66 Seaview Terrace, Sunshine Beach are
presented in Table 7 and the spatial extents are shown in Figure 21.
Table 7 Reassessed Erosion Prone Area for 66 Seaview Terrace, Sunshine Beach


                                Erosion Prone Area Component                    Value

                                Long-term Erosion (m)                             0

                                Short-term Erosion (m)                            58

                                Recession due to 0.8m SLR (m)                     11

                                Safety Factor                                    1.4

                                Dune scarp slumping (m)                           4

                                Erosion prone area Width (m)                     101




15 October 2021     66 SEAVIEW TERRACE, SUNSHINE BEACH                         PA2906-RHD-ZZ-XX-RP-Z-0001   30