24-01-2020 - Appeal No. 245 of 2019 - Final Order of Judge Rackemann · 51987.2951.01

Working Notes:
M Design and Fourteen Enterprises Pty Ltd as trustee v Noosa Shire Council -
42 Seaview Terrace, Sunshine Beach




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


4.1.    Water Levels
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.

4.1.1. Astronomical Tides
Sunshine Beach adjacent to the site experiences semi-diurnal tides with a tidal range of 1.4 metres
at Spring Tides. Table 3-1 presents the tidal planes for Noosa Beach published by Maritime Safety
Queensland (2019). These tidal planes are considered consistent with conditions at Sunshine Beach
due to the proximity of the two beaches.

Table 3-1 Noosa Beach Tidal Planes (Maritime Safety Queensland, 2019)
 Tidal Plane                      Water Level
                                    (m AHD)
 Highest Astronomical Tide             1.16
 Mean High Water Spring                0.66
 Mean High Water Neap                  0.33
 Mean Sea Level                       -0.06
 Mean Low Water Neap                  -0.41
 Mean Low Water Spring                -0.74
 Lowest Astronomical Tide              1.16

The Highest Astronomical Tide (HAT) is used as the basis for measuring the width of the short-term
erosion component of the erosion prone area.

4.1.2. Storm Tide
Storm tide is the total water level associated with the combination of the normal astronomical tide
and the tidal surge associated with 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 Aurecon
(2013).

BMT WBM (2018) adopted the 100 year ARI storm tide levels determined by Aurecon (2013) for the
reassessment of the erosion prone area widths for Noosa Shire, including Sunshine Beach. This is
consistent with industry practice and has also been adopted for this assessment.


4.1.3. Sea Level Rise
Sea levels are predicted to rise due to the effects of climate change. The Queensland Government
through the State Planning Policy has adopted a predicted sea level rise of 0.8 metres by the year
2100 above present day mean sea level. It is noted that BMT WBM (2018) adopted the following sea
level rise allowances (above present day mean sea level) as part of phase 3 of the CHAS:
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