Appendix D - Bushfire Hazard Assessment and Management Plan

3.0     LOCAL HAZARD MAP
3.1     GENERAL
The SPP reference documentation sets out the following methodology for preparing a Local Hazard Area
Map:
     Categorising the vegetation within the site in accordance with the vegetation hazard classes
        derived from QFES (2019) (refer to Figure 1)
     Using the patch and corridor filtering process to remove narrow corridors and small patches of
        hazardous vegetation (refer to Figure 1)
     Subdividing the identified vegetation hazard classes into bushfire hazard sub-units based on
        slope differences and vegetation hazard classes (refer to Figure 2)
     Assigning SPP Potential Bushfire Intensity classes to the sub-units (refer to Figure 2)
     Application of 100m Potential Impact Buffers to the amended sub-units to derive an overall Local
        Hazard Map (refer to Figure 3)

3.2     PATCH AND CORRIDOR FILTERING
Section 4.2.6 of Bushfire Resilient Communities (QFES, 2019) outlines the patch and corridor filtering
process to modify potential intensity of small patches and corridors (based on Leonard et. al. 2017). The
process involves the following three stages:
      Remove small, isolated patches of a single Vegetation Hazard Class less than 1ha if they are
         further than 100m from any other continuous fuel greater than 2 hectares in size
      Downgrade the intensity of small patches (0.5 to 3 ha). This process downgrades the effective
         fuel load of continuous vegetation patches 0.5 to 2ha by 66%, and 2 to 3ha by 50% if they are
         completely surrounded by either no fuel or by discontinuous fuel further than 100m from any
         other continuous-fuel vegetation patch greater than 2 hectares in size
      Removing narrow corridors of vegetation less than 50m wide and less than 0.5ha through a
         process of patch erosion and dilation. These small patches are merged with surrounding
         vegetation by allocating a patch to the Vegetation Hazard Class that is most common to the patch
         boundary.

3.3     CALCULATION OF POTENTIAL BUSHFIRE INTENSITY
Potential Bushfire Intensity of each identified sub-unit has been calculated by inputting the site-specific
input parameters discussed in Section 2.1 into the FLAMESOL computer model. FLAMESOL uses industry
standard bushfire equations and allows numerous input variables to be adjusted including fuel loads, fire
danger index, site slope and distance to vegetation. Table 1 details the Potential Bushfire Intensity classes
and their corresponding potential fire-line intensity (KW/m) values as prescribed within Leonard et. al.
2017. The Flamesol modelling used to determine the SPP Potential Bushfire Intensity classes has been
included as Appendix B.




DECEMBER 2021                BUSHFIRE HAZARD ASSESSMENT & MANAGEMENT PLAN                            Page: 11
                                      21 JIRRIMA CRESCENT, COOROIBAH