Reference Document - Coastal Hazard Assessment - MCU24 0094 · MCU24/0094

                                33 Ross Crescent, Sunshine Beach – Coastal Hazzard Assessment | 33 Ross Crescent Family Trust




Figure 6-9 Beach profile and storm profile ETA 602 (BMT, 2018)


6.4.2.   Depth of closure
BTM (2018) calculated the depth of closure to be around 11-12m for Noosa beaches and adopted 11.5m
for the Brunn Rule calculation. The assessment herein adopted 12m for the Brunn Rule calculation. This
small difference has a negligible effect on the Brunn Rule calculation.


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

The RHDHV (2024) and the assessment herein adopted a level of 2.3m AHD as the toe of the dune based
on site observations, detailed survey, the current vegetation line and interpretation across the creek mouth
based on the ‘Coastal Hazards Technical Guide’ (Department of Environment and Heritage Protection,
2013) (refer Section 2.4).


6.4.4.   Active beach width
The active beach width represents the horizontal distance from the dune height to the depth of closure.
BMT (2018) adopted active beach widths of 525m and 595m for ETA 602 and ETA596, respectively.

The assessment herein adopted an active beach width of 600m. The variation in these measurements is
attributed to the different dune heights adopted.


6.4.5.   Dune height
Figure 6-10 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 frontal dune
and therefore underestimates the reserve of sand available in the dune system.

RHDHV (2024) adopted a dune height of 7m AHD which was determine over an iterative process (see
Section 6.2.3). This assessment has shown the 7m AHD dune height is still appropriate with a 1.79m AHD
storm tide level.




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