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

A long-term erosion of 0 metres is considered more realistic given the effect of Noosa Headland
which would act in a similar fashion to a groyne by trapping sand moving north along the coast with
the prevailing south-easterly wave climate.


6.2.    Short-term Erosion (C)
The Department of Environment and Heritage Protection (2013) recommends the calculation of the
short-term erosion based on a 100 year ARI storm event using the methodology developed by
Vellinga (1983). Figure 5-1 shows a conceptual representation of the erosion and accretion zones
associated with storm induced erosion predicted by Vellinga (1983). The Department provides the
following recommendation in relation to defining a storm event:

       “For a tide-dominated coast where storm tide levels can be large, the parameters
       adopted for the minimum design storm are:
       (i)   storm tide level corresponding to an average recurrence interval of 1-in-100 years
       (ii) wave height for a moderate storm using the 1-in-20-year significant wave height (Hs).

       However, for wave-dominated coastlines where extreme storm tide levels can be
       relatively minor, such as the Gold Coast, the significant wave height and duration of the
       storm event are major factors influencing short term erosion, rather than storm tide.
       Hence it may be necessary to consider a larger wave event (for example, a storm event
       with a 1-in-100 ARI) and a moderate storm tide level. Decisions on appropriate
       parameters to be used must be based on local conditions and the experience of the
       coastal engineer undertaking the assessment.”




Figure 5-1 Sketch of pre-storm and predicted post-storm profiles based on Vellinga (1983)

In relation to the probability of such an event occurring the Department of Environment and
Heritage protection (2013) states:



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