Amended Bushfire Risk Assessment and Risk Management Plan

                          Ecological Natural Area Management

Patch and corridor filtering
Leonard et al (2014) specify a filtering process to remove or downgrade hazard levels of small
patches and narrow corridors of hazardous vegetation as fire-line intensity in these small patches
is unlikely to reach the level predicted for large contiguous patches of vegetation (Leonard et al
(2014), page 5). Using the map below, patch and corridor filtering was conducted.




Figure 10: Map of the patches of vegetation used for patch and corridor filtering


Patch filtering tabulation
Patch     Initial class               Merge class                   Reason for merge                           Potential load
Patch 1 Melaleuca woodlands           Melaleuca woodlands           No merge as patch is large. Remains as        19.7 t/ha
        on coastal swamps             on coastal swamps             Melaleuca woodlands on coastal swamps
Patch 2 Melaleuca woodlands           Melaleuca woodlands           No merge as patch is large. Remains as        19.7 t/ha
        on coastal swamps             on coastal swamps             Melaleuca woodlands on coastal swamps
Patch 3 Low grass or tree cover Low grass or tree cover No merge as patch is large. Remains as                     5 t/ha
        in rural areas          in rural areas          Low grass or tree cover in rural areas
Patch 4 Melaleuca woodlands           Melaleuca woodlands           No merge as patch is large. Remains as        19.7 t/ha
        on coastal swamps             on coastal swamps             Melaleuca woodlands on coastal swamps


6.4     Tabulation of the Potential Bushfire Intensity Class
Table 5: Tabulation of the potential bushfire intensity classes for each of the patches
      Patch      Vegetation class         Fuel load        Slope         FDDI     Fireline Intensity     Potential Bushfire
                                                                                                          Intensity Class
   Patch 1     Melaleuca                   19.7 t/ha        1.7 0          52        14054 kW/m               Medium
               woodlands on
   Patch 2     coastal swamps
               Melaleuca                   19.7 t/ha        1.0 0          52        13364 kW/m               Medium
               woodlands on
   Patch 3     coastal swamps
               Low grass   or tree            5 t/ha        1.0 0          52           861 kW/m                Low
               cover in rural areas
   Patch 4     Melaleuca                   19.7 t/ha        1.9 0          52        14274 kW/m               Medium
               woodlands on
               coastal swamps




Bushfire Risk Assessment and Management Plan for a small rural subdivision at 15 Jirrama Cr, Cooroibah             March 2022

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