2021-01-18 GC - Item 3 - Attachment 3 - Cost Benefit Analysis for Coastal Erosion Options

Appendix C: Sensitivity Analysis

The results for the Eastern Beaches and Teewah were also tested using a 7 per cent discount rate, in
line with standard CBA guidelines. Using a 7 per cent discount rate does affect the findings, with
option 3 (Beach Nourishment) going from a strongly positive NPV to close to zero. Other key
assumptions have also been tested but do not significantly affect the findings. The results are
provided in Table C1 and C2.

Table C1       Eastern Beaches results (Net present value)

                              Dune        Nourish       Seawall   Acquisition    Leaseback   Planning
                              (O2)         (O3)          (O4)        (O5)           (O6)       (O7)
 Central results          63            239            -2773      -222          -70          73
 7% discount rate         7             0.4            -370       -60           -5           19
 20% increase in
 implementation
 and
                          63            195            -2784      -222          -70          73
 management
 costs for all
 options
 Increase
 frequency of
 beach
 nourishment              63            106            -2773      -222          -70          73
 from every 5
 years to every 3
 years (option 3)
 20% reduction in
 tourism,
                          63            239            -2138      -256          -83          73
 recreation and
 non-use values
 Time period              36            114            -1851      -192          -40          50
 2020-2080




AITHER | Final Report                                                                                   30
Noosa Shire Council – Coastal Hazard Adaptation Plan