Reference Document - Coastal Hazard Assessment - MCU24 0094 · MCU24/0094

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



6.3.       Short-term Erosion (C)
The Department of Environment and Heritage Protection (2013) recommends the calculation of short-term
erosion based on a 100-year ARI storm event using the method developed by Vellinga (1983). The equation
developed by Vellinga is as follows:

                                                         .
 7.6                7.6   .                .
           = 0.47             .                  + 18        − 2.0
                                  0.0268

Where:
   =        Deep water significant wave height (m)
 =          Fall velocity of sand (m/s)
 =          The distance from the dune foot (m)
 =          Depth below storm surge (m)

The relationship between sediment grain size and fall velocity has been derived from laboratory tests and
is given by the following equation (Vellinga, 1983).


log    1     = 0.476 log            + 2.18 log       + 3.19


Where:
 =          Fall velocity of sand (m/s)
 =          The grain size of the sand (m)

Figure 6-1 shows a conceptual representation of the erosion and accretion zones associated with storm
induced erosion predicted by Vellinga (1983).




Figure 6-1 Sketch of pre-storm and predicted post-storm profiles based on Vellinga (1983)

The Department provides the following recommendation in relation to defining a storm event:




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