11. Appendix G - Bushfire Hazard Assessment & Management Plan

Bushfire Hazard Assessment & Management Plan v2                                                          NCES REF: J001313
Lot 4 on RP160124 – 658 Louis Bazzo Dr, Ringtail Creek QLD 4565




3.6 Quantitative Modelling
Quantitative modelling of the potential bushfire conditions that may be experienced within the VHC
8.1, 9.1, 24.1, & 36.1 hazardous open forest flanking the site has been undertaken to assist in
determining the suitability of the development and any asset setback requirements.
The models used comprise industry standard bushfire equations which have been built into the FPAA
endorsed FLAMESOL computer model. FLAMESOL allows numerous input variables to be adjusted
including fuel loads, fire danger index, site slope and distance to vegetation. FLAMESOL uses the
following algorithms:
        Rate of Spread – McArthur (1973) and Nobel et al. (1980)
        Flame Length – NSW Rural Fire Service (2001) and Nobel et al. (1980)
        Elevation of Receiver – Douglas and Tan (2005)
        Flame Angle – Douglas and Tan (2005)
        Radian Heat Flux – Drysdale (1999), Sullivan et al. (2003) and Douglas and Tan (2005)
The FLAMESOL Minimum Distance calculator has been used and comprises an AS 3959:2018
Method 2 (Appendix B) based calculator which can determine a suite of bushfire behaviour variables
including the minimum distances required to achieve a range of different radiant heat level
exposures.
Fuel load inputs have been derived from Planning for Bushfire Resilient Communities (QFES 2019)
based on the nominated potential fuel loads for:
         VHC 8.1 (31t/ha surface and near surface fuels and 35t/ha total fuels)
         VHC 9.1 (21t/ha surface and near surface fuels and 24.2t/ha total fuels)
         VHC 24.1(9.5t/ha surface and near surface fuels and 10.1t/ha total fuels)
         VHC 36.1 (23.8t/ha surface and near surface fuels and 26t/ha total fuels)
Table 2 summarises the slopes and flame width input variables assigned to each of the identified
Sub Units in the Flamesol modelling.
Note, effective slope was measured by utilising the closest adjacent section of the proposed
development as the point of reference when calculating the slope.
Table 2: Flamesol Input Summary

     Sub Unit &                   Effective Slope                       Site Slope                  Flame Width
    assigned VHC              (Maximum slope conditions           (Maximum slope conditions        (Width of the sub unit
                               underlying the hazardous           underlying the setback area   relative to a perpendicular
                               vegetation relative to the            located between the          fire run toward the site,
                                proposed development               hazardous vegetation and      default 100m maximum)
                                       footprint)                 the proposed development
                                                                           footprint)

   SU6 – VHC 36.1                  17º Downslope                      1° Across slope                    100m

   SU7a – VHC 9.1                1º Across/Upslope                    1° Across slope                    100m

   SU7b – VHC 9.1                  10º Downslope                      1° Across slope                    100m

   SU7c – VHC 9.1                  13º Downslope                      1° Across slope                    100m

   SU8a – VHC 24.1                  6º Downslope                      1° Across slope                    100m

  SU8b – VHC 24.1                1º Across/Upslope                    1° Across slope                    100m




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