PA3660-Coastal Hazard Assessment - 4 arakoon

                                                  Project related




6.3.1           Beach Profile
Beaches are in a state of dynamic equilibrium with the prevailing coastal processes and sediment supply
that results in the beach profile constantly changing in response to changes in conditions.

The beach profile adopted by BMT (2018) for ETA 602 is shown in Figure 6-10 and was derived from
2016 LiDAR data combined with the Sunshine Coast Bathymetric Lidar Data (2011) for the nearshore
section.

The beach profile for this assessment (refer Figure 6-4) was based on detailed site survey (refer
Appendix A) combined with the Sunshine Coast Bathymetric Lidar Data for the nearshore section. The
profiles are different and this impacts on the extent of erosion that may occur during the adopted design
storm event.




Figure 6-10 Beach profile and storm profile ETA 602 (BMT, 2018)


6.3.2           Dune Toe
BMT (2018) determined the dune toe position by utilising the manually digitized coastline from the
Department of Natural Resources and Mines (DNRM) and incorporating guidance from the Highest
Astronomical Tide (HAT) contour.

RHDHV have adopted a level of 2.25m AHD as the toe of the dune based on detailed survey and the
current vegetation line (refer Section 2.3).

6.3.3           Active beach width and height
The active beach width represents the horizontal distance from the dune height to the depth of closure.
According to BMT (2018) and RHDHV, the adopted active beach width measures 525m and 550m,
respectively. The variation in these measurements is attributed to BMT's approach of taking the dune
location as the frontal dune.

6.3.4           Dune height
Figure 6-11 shows the dune heights adopted by BMT (2018) and RHDHV against the beach profile
adopted for the assessment in this report. BMT (2018) adopted 4.9m AHD which corresponds to the



11 April 2024         4-6 ARAKOON CRESCENT, SUNSHINE BEACH          PA3660-RHD-XX-ZZ-RP-Z-0001   35