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

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9 August 2017

The detailed numerical assessment is presented in Appendix A. The conclusion of that assessment is
that the erosion prone area width (EPAW) should be reduced to 77 m, rather than the 175 m contained
in the current State mapping. On this basis, the erosion prone area lies outside the property boundary,
and has no effect on the site.

It is also noted that the development proponent will retain the vegetation on the site outside of the proposal
building envelopes. In particular, the vegetation on the downslope and dunes eastward of the building
line will be completely retained. This will provide an additional factor of safety against future erosion
which may affect the beach in this location.

State Assessment Development Provisions — State Code 8

Assessment against SDAP State Code 8: Coastal development and tidal works is triggered by the
application because the site is designated as erosion prone by DEHP. A completed template for State
Code 8 is attached. The project complies with all relevant Performance Outcomes with the notional
exception of PO1 (on the basis of the current State coastal hazard mapping). In that respect, the site is
currently included in the Erosion Prone area mapping for the local authority. However, a detailed
coastal assessment (see attached and above) has determined that the site is not erosion prone.

A detailed assessment against the State Code 8 provisions is included in Appendix B.
Coastal Protection Area (Noosa Shire Council Planning Scheme)

The site and the coastal areas seaward of it are classed as being in the Coastal Protection Area by
Council. Proposed development in these areas is therefore required to be assessed under Part 13
Overlays of the Planning Scheme, and in particular Division 10 - Natural Resources Overlay Code.
From an engineering point of view, the relevant specific outcome listed in that Code for coastal
protection areas is as follows:

018 The siting and design of development and materials used within the Coastal Protection
Area, as identified on the Natural Resources Overlay Maps, do not cause any significant
adverse impacts on the coastal resources of the location nor interrupt the natural cycles of
erosion and accretion of foreshore areas and beaches.

Given that the site-based coastal processes study carried out for this proposal has determined that the
site lies completely outside of the erosion prone area, O18 is obviously complied with.

A detailed assessment against the provisions of Noosa Shire’s Natural Resources Overlay Code is
included in Appendix C.

Flooding

Burgess Creek adjoins the site to the north. It has been determined that the peak water level in this
creek will be governed by storm tide conditions in the coastal zone. The peak water level for the 1%
Average Exceedance Probability (AEP) flood event is therefore expected to not exceed 3.2 m AHD,
taking into account an expected 0.8 m sea levei rise by 2100 as a result of climate change. All
proposed development on this site will be located above 14 m AHD, and the only part of the site which
is subject to flooding is the steep area adjoining Burgess Creek. No works will take place on this slope
below 14 m AHD. There are no flood impacts on the development proposal.

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