2021-10-08 SM - Item 1 - Attachment 1 - Draft Coastal Hazards Adaptation Plan

The cost benefit analysis7 found there is a positive net present value of $63m for the area between
Peregian Beach and Sunshine Beach, and $0.3m at Teewah. This is due to the very low costs of
action and the short-term benefits that the revegetation and dune management would provide.

While some amount of dune revegetation and management is underway that has important
benefits in slowing erosion, this work needs ongoing and enhanced resources and needs to involve
larger sections of beach than currently targeted to mitigate projected increases in erosion risks.
This management response is a critical and immediate priority for Council and the community in
helping to build climate resilience.

Beach nourishment, dune augmentation and management

This option involves a whole-of-beach management approach and includes repeated cycles of
sand nourishment, dune building and revegetation. Sand nourishment and dune building requires a
supply of additional sand to be added to the beach, in this case from an offshore resource.
Earthmoving equipment is used to shape the beach and dunes prior to revegetation work.

For Teewah Beach, this option is not considered feasible due to the high implementation costs
relative to the small number of properties affected by coastal erosion prior to 2100.

For the area between Peregian Beach and Sunshine Beach, the cost-benefit analysis found there
is a positive net present value of $239 million for this option. The increase in benefits is significant
and is attributed to the high property and asset values that exist along this stretch of beach that
would benefit from this option, relative to the cost of implementation. As such, this option is
considered a feasible option for implementation in the areas of high erosion risk.

It is important to note however that the costs associated with undertaking sand nourishment
(approximately $220 million to 2100) are significant. There is also significant uncertainty regarding
these costs due to the incomplete information on a reliable sand supply. In addition, the direct
beneficiaries of this option comprise a relatively small number of private landholders (relative to the
whole local government area). Therefore, as part of the CHAP implementation, Council will further
investigate sand supply, costs and potential funding options including consideration of who should
pay to ensure equitability for the Noosa community.


Planning scheme response (development controls)

Planning controls are currently in place for coastal development to limit the encroachment of
buildings and structures into the vegetated dune areas to preserve natural coastal processes of
erosion and sand accumulation. This includes building setbacks from the seaward boundary of lots
through the Noosa Plan 2020, as well as State coastal building lines for some lots under the
Coastal Protection and Management Act.

These planning controls are supported by maintenance of existing vegetated dune areas by
Council and local bushcare groups to enhance these vital buffer areas including active
management of weeds and pests, and fencing and replanting. Further planning in underway to
enhance this on-ground foredune management.

However, this current approach does not fully account for the increased erosion risk anticipated
over the coming decades as a result of sea level rise and projected increases in extreme weather.
Changes to the Noosa Plan 2020 are therefore needed to better plan for coastal erosion risks,
consistent with the State Planning Policy for coastal hazards.


7
    Aither, 2020. Noosa Shire Council – Coastal Hazard Adaptation Plan Cost Benefit Analysis


Noosa Council – Coastal Hazards Adaptation Plan                                                  Page 27