Bushfire Hazard Assessment & Management Plan

Bushfire Hazard Assessment & Management Plan – v2                              NCES REF: ELK 2016-04
Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin




4.0 RISK ASSESSMENT METHODOLOGY

The level of bushfire hazard risk acting on the site was assessed in accordance with the
methodology prescribed in PSP1 of the Noosa Plan which specifies the assessment be
undertaken in accordance with the now repealed Appendix 3 of the State Planning Policy 1/03
Guideline: Mitigating the Adverse Impacts of Flood, Bushfire and Landslide

Several investigative tools were utilized to determine the site specific bushfire hazard risk
including:

        Review of local aerial photography,
        Review of site and local topography,
        Review of DNRM’s Vegetation Management Support Map, and
        Inspection of the site in May 2016.

4.1 Appendix 3 of the State Planning Policy 1/03 Guideline: Mitigating the Adverse
Impacts of Flood, Bushfire and Landslide
Appendix 3 of SPP 1/03 utilizes a scoring system to assess bushfire risk based on three
loading factors: vegetation type, site aspect and slope. The total of all three loading factors is
used to determine a site’s severity of bushfire hazard.

4.1.1 Topography / Slope
Physical conditions such as slope and terrain can influence important fire behaviour
characteristics such as wind speed and direction, and the rate of spread of fire. Fire is known
to double its rate of spread with each 10% increase in slope, up to 30% (Webster 2000). Slope
also has the effect of ‘tipping’ a flame to an acute angle as it travels upslope, which brings a
flame, and fire front, closer to unburnt vegetation. As a result, tipping facilitates the preheating
of vegetation and can make vegetation combust and burn quicker (Webster 2000). Therefore,
it is desirable to locate developments within bushfire prone areas on terrain which will not
significantly accelerate/intensify fire behaviour (i.e. steep slopes).

Table A3.2: Hazard score for slope has been directly extracted from SPP1/03 and depicts the
hazard scores relevant to slope influence.




4.1.2 Aspect
Sites with west to north aspects are considered at greatest risk to potential bushfire impacts,
given their direct frontage to hot and dry northerly to westerly winds most commonly
associated with bushfire outbreaks.

Table A3.2: Hazard score for aspect has been directly extracted from SPP1/03 and depicts




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