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


Noosa Shire Council is currently undertaking coastal investigations in preparation of a Coastal Hazard
Adaptation Strategy (CHAS) through the QCoast2100 program. Phase 3 of the CHAS involves refining
the coastal hazard mapping, including the erosion prone area. The Erosion prone areas for Noosa
Shire have been recently reviewed by BMT WBM (2018) on behalf of Noosa Shire Council as part of
the Coastal Hazard Adaptation Study (CHAS).

The following sections will review each component of the Erosion prone area based on site specific
conditions relevant to the Subject Site.


6.1.    Long-term Erosion (N x R)
The long-term erosion component is based on the selected planning period (N) and the average
annual rate of long-term erosion (R).

In relation to the planning period, the Department of Environment and Heritage Protection (2013)
states, “The long-term erosion component (excluding sea level rise) of the calculation is often
cyclical in nature and typically of a decadal scale. For this reason, it is considered the estimated
annual rate of long-term erosion is only applied for a 50-year period”. Where there is no clear
evidence of log-term erosion trends the Department requires a nominal provision of 10 metres
which is not based on any scientific assessment. This nominal figure also increases the conservative
nature of the erosion prone area.

The annual rate of long-term erosion (R) reflects changes to sediment supply to a beach and where
there is a long-term deficit in sediment supply this results in a longer term recession of the shoreline.
BMT WBM (2018) has calculated the long-term erosion rate for Sunshine Coast at beach profile line
ETA 602. Table 5-1 provides a summary of BMT WBM (2018) estimated long-term erosion for 2040,
2070 and 2100.

Table 5-1 Summary of Long Term Recession Results from BMT WBM (2018)
 Beach                Profile       Annual                  Long-Term Erosion (m)
 Compartment                    Recession (m)
                                                      2040          2070          2100
                                                     N = 23        N = 53         N = 83
 Sunshine Beach    ETA 602.0         0.03              0.7           1.6           2.5

The calculation of an annual long-term erosion rate on 0.03 metres/year for Sunshine Beach by BMT
WBM (2018) has followed standard industry practice. However, the site is located approximately
400m south of Noosa Headland which will influence the sediment transport processes along this
section of coast by trapping sand moving north along the coast. It is therefore considered the
analysis of the long-term erosion component is conservative (i.e. by 7.5 metres) for the section of
beach adjacent to the site. This is supported by the assessment of aerial photography presented in
section 4 which has shown accretion of the beach adjacent to the site.

It is noted that BMT WBM (2018) had adopted a nominal 10m value for long-term erosion for
erosion prone area calculation over a 100 year planning period and this is in accordance with the
Department of Environment and Heritage Protection (2013) methodology. This is consistent with
the Department of Environment and Heritage Protection (2013) methodology however does not
consider the effect of the site’s proximity to Noosa Headland which will reduce long-term erosion.



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