2021-01-18 GC - Item 3 - Attachment 1 - Coastal Hazards Adaptation Plan for Community Consultation

to managing coastal erosion risks is essential to managing these risks across both the short and
long term on behalf of Noosa’s present and future community.

The technical studies performed throughout phases two through seven of this project, as well as
multiple rounds of community input, have revealed a set of adaptation options deemed most
appropriate for responding to coastal erosion risks in Noosa:

Dune revegetation and management.

This option includes revegetation and maintenance of at-risk dune areas, including weed and pest
control and fencing. This nature-based option is considered a preferred and feasible response for
mitigating coastal erosion risks due to the relatively low cost, high community support, ease of
implementation, consistency with the current scenic amenity of Noosa’s coastline, and lack of
adverse impacts. Importantly, this low-risk management response provides benefits through
delayed damage to properties and assets by helping to preserve the dune profile and stability for
longer. This supports other, more substantive erosion risk mitigation measures, such as planning
scheme responses (development controls).

The cost benefit analysis (Aither 2020a6) 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 resources and needs to involve larger
sections of beach than currently targeted to mitigate projected increases in erosion risks.


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.




6
    Aither, 2020a. Noosa Shire Council – Coastal Hazard Adaptation Plan Cost Benefit Analysis


Noosa Council – Coastal Hazards Adaptation Plan 2020 - 2030 (community consultation version)     Page 25