9.5.22 Bushfire Hazard Assessment Management Plan v2 - 60 Glenridge Drive COOROIBAH

Bushfire Hazard Assessment & Management Plan v2                                 NCES REF: J001001
Lot 47 on RP860577 – 60 Glenridge Drive, Cooroibah




3.6 Quantitative Modelling
Quantitative modelling of the potential bushfire conditions that may be experienced within the
VHC 22.1 Melaleuca open forest to be revegetated within the site and adjoining parts of 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 will determine standard bushfire
behaviour variables as well as the minimum distances required to achieve a range of different
radiant heat levels (represented by BAL's).
Fuel load inputs have been drawn from Planning for Bushfire Resilient Communities (QFES
2019) based on the calculated potential fuel loads for VHC 22.1 (23.4 t/ha surface and near
surface fuels and 28.4 t/ha total fuels). 1º effective slope was adopted for the slope underlying
the VHC 22.1 Melaleuca open forest given across slope conditions underlying the vegetation.
The default Flame Width of 100m was chosen given the large variance in the edge width of
the onsite and offsite VHC 22.1 Melaleuca Forest vegetation.
A Forest Fire Danger Index (FFDI) of 47 has been adopted for the site consistent with the
assignment by QFES (Catalyst 2020) (refer Plate 8).




                                     Plate 5 – FFDI (Source: QFES redi Map)

The Flamesol output results are shown in Plate 9.




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