MNA_250215_33 Ross Crescent Sunshine Beach_00

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



5.        Coastal Processes
The coastal processes of interest to this investigation are water levels (including sea level rise predictions),
wave conditions, and sediment transport processes.

5.1.      Tides and Storm Tide
The water levels of interest for a reassessment of the erosion prone area include the astronomical tide,
storm tide and the predicted rise in mean sea level associated with climate change. The following sections
describe the water levels adopted for the assessment.
5.1.1.    Astronomical Tide
Sunshine Beach experiences semi-diurnal tides with a tidal range of 1.4m at spring tides. Table 5-1
presents the published tidal planes for Noosa Head (Maritime Safety Queensland, 2024) which are
considered consistent with conditions at Sunshine Beach, due to the proximity.

TABLE 5.1: NOOSA HEAD TIDAL PLANES (MARITIME SAFETY QUEENSLAND, 2024)
 Tidal Plane                   Water Level           Water Level
                             (m above LAT)             (m AHD)
 Highest Astronomical Tide        2.35                   1.23
 Mean High Water Spring           1.85                   0.66
 Mean High Water Neap             1.52                   0.33
 Mean Sea Level                   1.15                   -0.06
 Mean Low Water Neap              0.79                   -0.41
 Mean Low Water Spring            0.45                   -0.74
 Lowest Astronomical Tide           -                    -1.12

5.1.2.    Sea Level Rise
The effects of climate change associated with emission of greenhouse gases has caused a rise in mean
sea level above pre-industrial levels, and sea levels are predicted to continue to rise into the future. The
Queensland Government has adopted a predicted sea level rise of 0.8m by the year 2100 above present
day mean sea level. It is noted that BMT (2018) adopted the following sea level rise allowances (above
present day mean sea level) as part of phase 3 of the Coastal Hazard Adaptation Strategy (CHAS):

     •   0.2m by 2040,
     •   0.5m by 2070, and
     •   0.8m by 2100.

The adopted sea level rise allowances are consistent with industry practice and will be used for this
assessment.
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 5-2.

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


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