MCU25 0087 - Reference Document - Coastal Hazard Assessment (As Published)

                                                                  17 The Esplanade, Sunshine Beach                              Report


                      The beach profile adopted by BMT (2018) for ETA 602 is shown in Figure 5-11 and was derived from
                      (LIDAR, 2016) data combined with the Sunshine Coast Bathymetric (Department of Environment and
                      Science, 2011) for the nearshore section.
                      The beach profile for this assessment (refer Figure 5-11) was based on detailed site survey (refer
                      Appendix C) supplemented with a Digital Elevation Model (ELVIS, 2024) for the stable high dune
                      areas. The profiles are different and this impacts on the extent of erosion that may occur during the
                      adopted design storm event.




                                                  Figure 5-11 ETA 602 Beach profile and storm ETA 2100

                      5.3.2    Depth of Closure
                      The depth of closure adopted BMT (2018) was -11.5m AHD. However, M&N has adopted a depth of
                      closure of -12m AHD. This difference is unlikely to significantly alter the Bruun Rule calculation.
                      5.3.3    Dune of Toe
                      BMT (2018) determined the dune toe position by utilising the manually digitised coastline from the
                      Department of Resources and incorporating the Highest Astronomical Tide (HAT) contour.
                      M&N have adopted a level of 2.3m AHD as the toe of the dune based on site inspection (seaward
                      edge of vegetation) and detailed survey (refer Section 2.4).
                      5.3.4    Active beach width and height
                      The active beach width represents the horizontal distance from the dune crest to the depth of closure.
                      According to BMT (2018) and M&N, the adopted active beach width measures 525m and 520m,
                      respectively. The variation in these measurements is attributed to BMT's approach of taking the dune
                      location as the frontal dune.
                      5.3.5    Dune height
                      Figure 5-12 Dune heights and beach profile shows the dune heights adopted by BMT (2018) and
                      M&N against the beach profile adopted for the assessment in this report. BMT (2018) adopted 4.9m
                      AHD which corresponds to the frontal dune and therefore underestimates the reserve of sand
                      available in the dune system. M&N adopted a dune height of 15m AHD which was determine over an
                      iterative process (see Section 5.2.3).




                                                                                      252662-MN-RP-CO-0001B | 10 November 2025 | Page 32

Document Set ID: 24631530
Version: 1, Version Date: 24/03/2026