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


3         BUSHFIRE HAZARD ASSESSMENT

3.1       Hazard Assessment Methodology
A site-specific hazard assessment has been undertaken using a combination of methodologies from
the following sources:
      ·    A new methodology for State-wide mapping of bushfire prone areas in Queensland (Leonard
           et al., 2014) for:
                o    Attribution of Vegetation Hazard Classes;
                o    Calculation of Potential Bushfire Intensity; and
                o    Patch and corridor filtering.
      ·    State Planning Policy Guideline – Mitigating the Adverse Impacts of Flood, Bushfire and
           Landslide (June, 2003) which was used as a guide for undertaking natural hazard
           assessment on a site-specific scale; and
      ·    The Noosa Plan’s 2006 Bushfire Hazard Overlay Code.
The following sections detail the methodology used to determine the bushfire hazard risk acting on
the site.
3.2       Local Bushfire Hazard Mapping
A Local Hazard Area Map was prepared in two stages by adopting the following methodology:
      ·    Categorizing the vegetation within the site in accordance with the vegetation hazard classes
           derived from Leonard et al. (2014);
      ·    Subdividing the identified vegetation hazard classes into bushfire hazard sub-units based on
           slope categories and vegetation hazard classes. All upslope and across slope vegetation
           units relative to building positions, are allocated an underlying slope of 0 degrees as per
           methodology prescribed within the State Planning Policy Guideline – Mitigating the Adverse
           Impacts of Flood, Bushfire and Landslide (2003). Narrow vegetated gullies aligned parallel
           to the direction of attack upon buildings have also been applied a 0-degree slope category
           given the equalizing impact of both positive and negative creek bank slopes;
      ·    Using the patch and corridor filtering process identified in Leonard et al. (2014 and 2017) to
           amend the bushfire hazard sub-units1. Patch filtered sub units are denoted by dashed sub
           unit boundaries on Figure 3; and
      ·    Application of 100m Potential intensity buffers to the amended sub-units to derive an overall
           Local Hazard Area Map.
The sub-unit level Local Hazard Area Map is presented in Figure 2 and the overall Local Hazard
Area Map is presented in Figure 3. The subsequent Local Hazard Area Map identifies the following
Potential Bushfire Intensity areas within the assessment area:
      ·    Medium Potential Bushfire Intensity area; and
      ·    Potential Impact Buffer.
The Local Hazard Area Map presented in Figure 3 supersedes the SPP broadscale mapping
attributed to the site and has been used to guide the formulation of appropriate site-based bushfire
management measures herein.

1
  The patch and corridor filtering process to remove or downgrade hazard levels of small patches and narrow corridors involves the
following three stages:
      ·    Merging small patches of a single Vegetation Hazard Class less than 0.5 ha;
      ·    Merging small Vegetation Hazard Class patches between 0.5 and 1 ha with higher or moderate fuel loads (greater than 8
           tonnes/ha); and
      ·    Removing narrow corridors of vegetation less than 100m wide through a process of patch erosion and dilation. These small
           patches are merged with surrounding vegetation by allocating a patch to the Vegetation Hazard Class that is most common to
           the patch boundary (Leonard et al., 2014).




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