Appendix E - Bushfire Hazard Assessment.pdf

                                                  [13]


       Risks and Resilience – Technical Manual – A fit for Purpose approach in undertaking natural
       hazard studies and risk assessment (April 2016)

Table 2 - Fireline Intensity Model Data for vegetation in Giraween Nature Refuge and
surrounding vegetation to the east and north of the subject site

 Characteristic                                        Input/output value
 Vegetation hazard class                               9.1 Moist to dry eucalypt open forests on
                                                       coastal lowlands and ranges
 Potential fuel load (t/ha)                            24.1 t/ha
 FFDI                                                  55
 Slope (degrees)                                       5.58 degrees
 Potential fireline intensity (kW/m)                   29,963 kw/m
 Potential Bushfire Hazard Class                       High
    i.   The VHC 9.1 – moist to dry eucalypt open forests on coastal lowlands and ranges has been
         used based on the RE mapping and species observed during the site inspection.
   ii.   The Potential fuel load is attributed with a potential fuel load by the State Government after
         Leonard et al. (2014).
  iii.   The FFDI for area is determined by the State Government after Leonard et al. (2014).
  iv.    The slope was estimated using slope analysis and field data.

With regard to the radiant heat flux and the minimum setback distance necessary to achieve an
acceptable level of risk, as defined under the State Governments, Bushfire Resilience Communities,
Technical Reference Guide for the State Planning Policy (Oct 2019), using the AS3959 Minimum
Distance Calculator with an FFDI of 48, a Vegetation Hazard Class of 9.1 – Moist to dry eucalypt open
forest on coastal lowlands and ranges, an downslope characteristic of 8 degrees and a surface fuel
load of 17.2t/ha and a total fuel load of 24.2t/ha the calculations is provided below in Table 3.

Calculated October 9, 2020, 4:49 pm (MDc v.4.8)

Table 3- Noosa Springs - Minimum Distance Calculator - AS3959-2018 (Method 2)

 Inputs                              Outputs
 Fire Danger Index     48            Rate of spread                    1.75 km/h
 Vegetation            Forest        Flame length                      14.28 m
 classification
 Surface fuel load     17.5 t/ha     Flame angle                       54 °, 64 °, 72 °, 76 °, 78 ° & 83 °
 Overall fuel load     24.2 t/ha     Elevation of receiver             5.57 m, 6.14 m, 6.39 m, 6.36 m,
                                                                       6.31 m & 5.47 m
 Vegetation height     n/a           Fire intensity                    21,888 kW/m
 Effective slope       8°            Transmissivity                    0.872, 0.854, 0.828, 0.803, 0.79
                                                                       & 0.728
 Site slope            1°            Viewfactor                        0.599, 0.4456, 0.3007, 0.2045,
                                                                       0.1663 & 0.0451
 Flame width           100 m         Minimum distance to < 40          11.7 m
                                     kW/m²
 Windspeed             n/a           Minimum distance to < 29          15.7 m
                                     kW/m²

Bushfire Hazard Assessment | Noosa Springs RFA17-040                                             22 April 2021
                                     Rob Friend & Associates Pty Ltd