2019-07-09 P&E Agenda - Item 10 - Attachment 1 - Coastal Hazards Risk, Vulnerability and Adaptation Assessment

Noosa Shire Council Coastal Hazard Mapping                                                                    5
Storm Tide Hazard Assessment




                      Table 2-1      Summary of CHAP Storm Tide Hazard Mapping Approach

           Mapping product            Present-day           2040              2070               2100
           Open coast storm            Developed         Developed         Developed           Developed
           tide inundation           using present-    using present-    using present-        using 2100
                                     day open coast    day open coast    day open coast        open coast
                                     levels reported   levels + 0.2 m    levels + 0.5 m     levels reported
                                       by Aurecon       SLR reported      SLR reported         by Aurecon
                                       (2013) and        by Aurecon        by Aurecon        (2013) (which
                                         bathtub         (2013) and        (2013) and        included 0.8m
                                        mapping            bathtub           bathtub            SLR) and
                                                          mapping           mapping              bathtub
                                                                                                mapping
           Lower Noosa River           Previously         Developed         Developed         Previously
           catchment storm tide       completed by      using existing    using existing     completed by
           inundation                Aurecon (2013)    TUFLOW model      TUFLOW model       Aurecon (2013)
                                                        + 0.2 m SLR       + 0.5 m SLR       (which included
                                                          boundary          boundary          0.8m SLR)
                                                           condition         condition
                                                         adjustments       adjustments
           Coincident Noosa           Previously         Previously        Previously         Previously
           River flooding and        completed by       completed by      completed by       completed by
           storm tide conditions     (WMA Water,        (WMA Water,       (WMA Water,        (WMA Water,
                                       2017a)             2017b)            2017b)             2017a)




2.2      Open Coast & Lower Noosa River Storm Tide Inundation
         The open coast and lower Noosa River storm tide hazard depth and extent for the CHAP planning
         horizons are presented in Appendix A. The method for deriving the ‘storm tide only’ coastal hazard
         area is described in this section.

         Current climate open coast storm tide levels for the Noosa local government area are reported in
         Aurecon (2013). For return periods up to the 100 year ARI, the levels are based on the following:

         • Analysis of tidal residual data recorded at Mooloolaba Harbour Entrance by fitting a Generalised
           Extreme Value (GEV) distribution to the data.

         • Generation of a synthetic record of surge plus tide level by independent sampling of the tidal
           residual distribution and a derived high tide distribution (based on published tidal constituent
             data for Mooloolaba).

         • Analysis of the synthetic surge plus tide record at Mooloolaba by fitting a GEV distribution to the
           data.

         • Extrapolation of the surge plus tide levels at Mooloolaba to other Sunshine Coast locations with
           reference to the spatial distribution of storm tide levels reported by Connell Wagner (2005) and
             Hardy et al. (2004).

         • An allowance for wave setup (discussed further below)




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