Bushfire Hazard Management Plan OPW20-0051 3 of 3 - Copy

Bushfire Hazard Management Plan v3                                                        NCES REF: J000662
Lot 101 on SP142407, Lot 140 on MCH978, Lot 3 on RP137375,
Lot 2 on RP852009 and Lot 8 on RP160703 - 27 Wilgee Court, Cooroy



4     BUSHFIRE RISK ASSESSMENT

4.1       General
The following sections provide an overall bushfire risk assessment for the proposed post
development conditions, which has been prepared generally in accordance with State Planning
Policy – State Interest Guideline – Natural Hazards, Risk and Resilience (DILGP, 2016) and
AS/NZS ISO 31000:2009 – Risk Management Methodology.
The bushfire risk assessment details the likelihood that the proposed development will be
exposed to bushfire smoke, ember, radiant heat and/or flame attack considering the proximity to
bushfire prone vegetation and likely bushfire behaviour. The risk assessment has assumed that
all proposed risk mitigation measures detailed in Section 5 of this report are implemented and
maintained.
According to AS/NZS ISO 31000:2009, a ‘hazard’ is defined as a source of potential harm or a
situation with a potential to cause loss, whereas a ‘risk’ is the chance of something happening
that will have an impact on objectives measured in terms of consequences and likelihood. The
State Planning Policy – State Interest Guideline – Natural Hazards, Risk and Resilience (DILGP,
April 2016) refers to ‘acceptable risk’, ‘tolerable risk’, and ‘intolerable risk’ which are defined
below.
      ·    Acceptable risk
              o     A risk that, following an understanding of the likelihood and consequences, is
                    sufficiently low to require no new treatments or actions to reduce risk further.
                    Individuals and society can live with this risk without feeling the necessity to reduce
                    the risks any further.
      ·    Tolerable risk
              o     A risk that, following an understanding of the likelihood and consequences, is low
                    enough to allow the exposure to continue, and at the same time high enough to
                    require new treatments or actions to reduce risk. Society can live with this risk but
                    believe that as much as is reasonably practical should be done to reduce the risks
                    further.
      ·    Intolerable risk
              o     A risk that, following an understanding of the likelihood and consequences, is so
                    high that it requires actions to avoid or reduce the risk. Individuals and society will
                    not accept this risk and measures are to be put in place to reduce risks to at least
                    a tolerable level.

4.2       Risk from Hazardous Vegetation Within the Site
All lots are proposed to be comprehensively cleared excluding the land area in each lot proposed
to be registered under conservation covenant. Therefore the hazardous vegetation proposed to
be retained within the site comprises a small patch of VHC 02 Open forests / woodlands – shrubby
in the far south of Lot 6, a riparian corridor of VHC 02 on the centrally located watercourse and a
linear tract of VHC 02 and VHC 08 – Acacia communities along the north-west and northern
boundaries of the development site.
The northern tract of VHC 02 is positioned on a maximal land slope of 10º downslope of the
adjacent building envelopes hence the underlying slopes can be expected to exacerbate the
potential severity and intensity of a bushfire, via flame tipping and preheating/drying of fuel loads,
as it travels over inclining slopes towards the sensitive receivers.
VHC 02 vegetation straddles either bank of the central watercourse and therefore the underlying
slopes offer both positive and negative slope conditions. The limited vegetated slope length
within the creek environs infers that the slope characteristics are unlikely to significantly influence
fire behaviour and it is expected the flammability of the in-situ floristics would generate more
influence on fire behaviour.



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