Attachment 7 - Bushfire Report · MCU18/0015

6.3        Anticipated severity of bushfire attack

Values for vegetation type, fuel load and slope are carried forward to Table 5, to predict the key fire parameters for the potential worst case fire scenario.

Fire Scenario – BLE Lot 2      Fire Scenario – BLE Lot 4       Fire Scenario – BLE Lot 4       Fire Scenario – BLE Lot 4       Fire Scenario – Units 1 - 12
Attack from N and E            Attack from N                   Attack from W                   Attack from S                   Attack from N and E
Fuel Area 1                    Fuel Area 6                     Fuel Area 5                     Fuel Area 5                     Fuel Area 2, 3, 5
Fire Run 25 – 30m              Fire run 125m                   Fire run 50m                    Fire run 80m                    Fire Run 60m
Method 2 AS3959-2009           Method 2 AS3959-2009            Method 2 AS3959-2009            Method 2 AS3959-2009            Method 2 AS3959-2009
FDI 50                         FDI 50                          FDI 50                          FDI 50                          FDI 50
Forest @ 6/11t/ha.             Forest @ 5/7t/ha.               Forest @ 6/11t/ha.              Forest @ 5/7t/ha.               Forest @ 6/11t/ha.
Ave Slope under vegetation     Ave Slope under vegetation 1⁰   Ave Slope under vegetation 0⁰   Ave Slope under vegetation 0⁰   Ave Slope under vegetation 21⁰
21⁰ Down                       Down                            Upslope                         Upslope                         Down
Fire Intensity (Byram, 1959)   Fire Intensity (Byram, 1959)    Fire Intensity (Byram, 1959)    Fire Intensity (Byram, 1959)    Fire Intensity (Byram, 1959)
8 714kW/m                      1 163kW/m                       2 046kW/m                       1 085kW/m                       8 714kW/m
(“MEDIUM”)                     (“LOW”)                         (“LOW”)                         (“LOW”)                         (“MEDIUM”)
Rate of Spread (Noble et al,   Rate of Spread (Noble et al,    Rate of Spread (Noble et al,    Rate of Spread (Noble et al,    Rate of Spread (Noble et al,
1980)                          1980)                           1980)                           1980)                           1980)
1.53kph                        0.32kph                         0.36kph                         0.3kph                          1.53kph
Flame Height (modified Mc      Flame Height (modified Mc       Flame Height (modified Mc       Flame Height (modified Mc       Flame Height (modified Mc
Arthur V equation, NSW RFS     Arthur V equation, NSW RFS      Arthur V equation, NSW RFS      Arthur V equation, NSW RFS      Arthur V equation, NSW RFS
2001) 11.29m                   2001) 2.93m                     2001) 3.66m                     2001) 2.79m                     2001) 11.29m
Flame Width 10.6m              Flame Width 40m                 Flame Width 40m                 Flame Width 40m                 Flame Width 30m
Elevation of Receiver 2.4m     Elevation of Receiver 2.4m      Elevation of Receiver 2.4m      Elevation of Receiver 2.4m      Elevation of Receiver 2.4m
BAL FZ within <8m of intact    BAL FZ within <3m of intact     BAL FZ within <4m of intact     BAL FZ within <3m of intact     BAL FZ within <10m of intact
unmanaged vegetation           unmanaged vegetation            unmanaged vegetation            unmanaged vegetation            unmanaged vegetation
BAL 40 from 8 - <9m            BAL 40 from 3 - <4m             BAL 40 from 4 - <5m             BAL 40 from 3 - <4m             BAL 40 from10 - <12m
BAL 29 from 9 - <12m           BAL 29 from 4 - <6m             BAL 29 from 5 - <7m             BAL 29 from 4 - <5m             BAL 29 from 12 - <17m
BAL 19 from 12 - <14m          BAL 19 from 6 - <8m             BAL 19 from 7 - <10m            BAL 19 from 5 - <8m             BAL 19 from 17 - <21m
BAL 12.5 from 14 – 100m        BAL 12.5 from 8 – 100m          BAL 12.5 from 10 – 100m         BAL 12.5 from 8 – 100m          BAL 12.5 from 21 – 100m

Table 5. Calculated values for potential bushfire characteristics, and methods used.

The predicted fireline intensity for all Fuel Areas assessed is in the “Medium” range for Lot 2 and Units 1 to 12, as indicated in State hazard mapping (Figure 4).

Predicted fireline intensity for Lot 3 is “Low” however rather than argue for a reclassification of the hazard, as a precaution the calculated BAL values from Table
5 are applied to any future dwelling on this Lot.




Report compiled by Bushfire Risk Reducers for Innovative Planning Solutions                                     Page 18