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

                                               Internal use only




5.1.3       Storm Tide
Storm tide is the total water level associated with the combination of the normal astronomical tide and the
tidal surge from a storm event (e.g., tropical cyclone). There have been several previous storm tide
studies undertaken for the Sunshine Coast with the most recent being the ‘Sunshine Coast Storm Tide
Study’ (Aurecon, 2013). The design storm tide levels determined by Aurecon (2013) for the 100, 500 and
1000-year ARI events are presented in Table 2.

Noosa Shire Council has undertaken a broad-scale reassessment of coastal hazards from Peregian
Beach to Teewah Beach as part of the ‘Noosa Shire Council Coastal Hazards Risk, Vulnerability and
Adaptation Assessment’ (BMT, 2018). The 100-year ARI storm tide level of 1.74m AHD was adopted by
BMT (2018) for the reassessment of the erosion prone area width at Sunshine Beach.

To address the SDAP (Performance Outcome 6 of State Code 8) outlined in Section 3.1 the vulnerability
of the proposed property and house to an extreme storm events has been considered and assessed. As
discussed in the introduction, a 500-year ARI storm tide level has been adopted for the extreme analysis
with an allowance for climate change induced sea level rise of 0.8 metres. The extreme event
assessment is discussed further in Section 6.1.2.
Table 2 Adopted Storm Tide Levels (excluding wave setup) for Sunshine Beach (Aurecon, 2013)


                                                                   Current Climate
                                           Return Period
                                                                  Storm Tide Level
                                            (years ARI)
                                                                      (m AHD)

                                                100                     1.74

                                                500                     1.84

                                                1000                    1.89




5.2         Wave Climate
The wave climate at Sunshine Beach is influenced by both locally wind-generated sea and ocean swell.
Sea describes wind generated waves where wind energy is still being transferred to the ocean. Swell
describes wind generated waves that have travelled out of their generating area. Swell characteristically
exhibits smoother, more regular, and uniform crests and a longer period than wind waves. In open coastal
areas sea waves generated by local winds are often superimposed on swell waves.

The wave climate for Sunshine Beach has been previously reported by BMT (2013), ‘Coastal Processes
Study for the Sunshine Coast’ prepared for the Sunshine Coast Regional Council. BMT WBM (2013) has
shown the wave climate for Sunshine Beach is dominated by waves from the east-southeast direction
(refer Figure 15).

The design offshore significant wave heights for the Sunshine Coast have been previously published by
BMT (2013), refer Figure 16. For this assessment a 100-year ARI offshore significant wave height of 6.2
metres has been adopted to be consistent with the BMT (2013) assessment.




15 October 2021      66 SEAVIEW TERRACE, SUNSHINE BEACH                        PA2906-RHD-ZZ-XX-RP-Z-0001   20