2021-01-18 GC - Item 3 - Attachment 2 - Phase 7 Project Summary Coastal Hazards Adaptation Plan

 Noosa Shire Council Coastal Hazard Adaptation Plan: Project Summary                                         30
 Findings




        Locality                Potential Adaptation Options (in order of             Adaptation Hierarchy
                                preference)                                           Approach
        Tewantin                Design of hazard resilient infrastructure             Prepare/Accommodate
                                Tide flaps and valves on stormwater pipe network
        Noosa North Shore       Design of hazard resilient infrastructure             Avoid/Prepare
                                Reduce intensity of future development
        Lake Cootharaba         Design of hazard resilient infrastructure             Prepare
                                Relocate important infrastructure
                                Land management to support habitat migration


3.6        Phase 7: Socio-economic Appraisal
           Following the MCA Assessment, a Cost-Benefit Analysis (CBA) was performed by Aither on two
           regions within the Noosa region: the open coast and Noosaville (Aither, 2020a and b). The options
           chosen were primarily those that were favoured by the MCA analysis, with some minor adjustments
           made e.g. an additional option of changes to planning regulations was added to the Eastern Beaches.
           The findings of the CBA are provided below.

3.6.1      Open Coast Locations
           A cost-benefit analysis (CBA) was performed for a range of options for open coast locations (Teewah
           and the Eastern Beaches) where risks were rated as high or very high by 2100. The Noosa Main
           Beach compartment was not included due to the limited capacity to carry out measures in addition
           to those already in place in this location (as noted in Section 3.5.3).

           The analysis identified that option 3 (dune revegetation and beach nourishment/augmentation) would
           provide the greatest economic net benefit for managing erosion risks along the Eastern Beaches, for
           the options assessed. The benefits of this option are driven by the significant value provided by the
           continued natural protection of high value beachfront properties, however it is recognised that this
           option may only be of value in the short term and is ranked high because of the low cost of
           implementation rather than the delivery of significant benefits.

           Uncertainties remain regarding the reliability of a sufficient offshore sediment supply over the long
           term due to incomplete understanding of existing sediment volumes, and changes to sediment
           movements into the local offshore zone in the latter half of the study period.

           Option 7 (changes to planning regulations) would also deliver net economic benefits, although the
           net benefits are lower than under option 3. Implementing planning restrictions, alongside dune
           augmentation in viable locations is likely to deliver socio-economic benefits to the community and
           reduce risks.

           Option 4 (construction of seawalls in high risk locations) had the least socio-economic benefit due to
           loss of amenity, low community support, impacts on the tourism economy, and cost of construction.

           Options 5 (property acquisition and conversion to public property) and 6 (Option 5 with a 15-year
           leaseback of properties prior to conversion to public open spaces) were the most economically viable
           for Teewah of all options analysed.