2 David Low Way - Attachment 4 - Specific Engineering Assessments - Cardno 10-8-17

1.1.6 Dune Scarping Component (D)

Dune slump (D) was accounted for in the SBEACH modelling, but there is no dune at the resort beach,
which is not proposed as the main resort beach amenity, which will be an internal beach around the

main pool.

1.2 Erosion Prone Area Width
This analysis begins with analyses of two sets of data, namely historical aerial photographs and LIDAR.

1.2.1 Long Term Erosion

The aerial photographs were examined and historical vegetation lines determined on each photograph.
The vegetation line varies with storm events and changes in sea level, as well as losses in sand from
potential offshore and alongshore sediment transport. They may also vary as a result of human and
animal traffic, which lead to blow-outs, sand mining and stream flows. Figure 1.1 shows these
vegetation lines relative to the Castaways Beach development site — in red. Aerial photographs for the
following dates and were available and applied to these analyses:-

6 May 1958

25 September 1961
10 July 1973

July 1977 (no day specified)
20 April 1979

29 October 1982

5 September 1990
1 August 1996

25 July 2002

11 June 2004

21 July 2010

3 July 2012

25 May 2016

17 February 2017