Draft BPAM WA Standard Section 7 and Associated Appendix

Draft BPAM WA Standard Section 7 and associated Appendix:

7.  IDENTIFYING THE BUSHFIRE-PRONE AREA

7.1  Intent

The purpose of the State-wide Bushfire-Prone Area Map (State Map) being a binary methodology (designation being either bushfire-prone area or not applicable), identifies bushfire prone vegetation with the intent to inform the application of AS 3959-2009 Construction of building in bushfire prone areas (AS3959) in accordance with (draft) State Planning Policy 3.7: Planning for Bushfire Risk Management (SPP3.7).

Developments within bushfire-prone areas and buffers will be required to undergo a Bushfire Attack Level (BAL) assessment by an accredited BAL 1 Assessor (using the simplified method within AS3959). The State Map does not measure bushfire fuels or bushfire risk. Bushfire risk and subsequent treatments and controls will be determined through the application of AS/NZS ISO 31000 Risk management - Principles and guidelines (ISO 31000).

7.2  Identifying the Bushfire-Prone Area

The bushfire-prone vegetation and the bushfire-prone buffer collective is a dataset and used to create the bushfire-prone areas identified on the State Map. These areas will be used for the purposes of applying SPP3.7, the (draft) Planning for Bushfire Risk Management Guidelines and AS3959.

In most cases, desktop assessment and utilising existing local knowledge is an adequate process for verifying the bushfire-prone vegetation data. A field assessment would be appropriate where data or local knowledge is not sufficient to make a determination.

The methodology for generating the bushfire-prone vegetation and bushfire-prone buffer datasets is identified below.

7.3  Assessing Bushfire-Prone Vegetation

As previously mentioned the bushfire-prone vegetation is classified in accordance with the AS3959. It was initially derived through existing datasets, and will be further improved by a range of measures including local level verification, aerial photography interpretation and some field validation. The vegetation identification process includes the following vegetation communities [1] (refer to Appendix 2 – Vegetation Key):

a.  Forest

b.  Woodland

c.  Shrubland

d.  Scrub

e.  Mallee/Mulga

f.  Rainforest

g.  Grassland

In addition to the AS3959, other vegetation for consideration includes:

h.  Bare areas

i.  Isolated areas

j.  Wetlands

k.  Managed Grasslands

7.3.1  Inclusions Areas

Land containing at least one of the bushfire-prone vegetation communities identified in the Vegetation Key – Appendix 2 shall be identified as bushfire-prone vegetation in accordance with the following criteria:

1.  All parcels of the above vegetation that are greater than 1 hectare in size shall be identified as bushfire-prone vegetation.

2.  Single areas of bushfire-prone vegetation that are between 0.25 and 1 hectare in area and are within 100 metres of other parcels of vegetation in the identified communities greater than 1 hectare in size shall also be identified as bushfire-prone vegetation.

7.3.2  Exclusions Areas

Land containing the above vegetation communities shall NOT be identified as bushfire-prone vegetation in accordance with the following criteria:

1.  Single areas of vegetation less than 1 hectare in area and not within 100 metres of other parcels of vegetation shall be omitted.

2.  Multiple areas of vegetation less than 0.25 hectare in area and not within 20metres of each other shall be omitted.

3.  Strips of vegetation less than 20 metres in width regardless of length and not within 20metres of each other or other areas of bushfire-prone vegetation shall be omitted.

In addition to the above criteria, any areas of managed grassland that are maintained in a minimal fuel condition in perpetuity, or that are free from vegetation, are not to be identified as bushfire-prone vegetation and will not be shown in the bushfire-prone area dataset. This will be monitored by the respective local government.

7.3.3  Grasslands

AS3959 currently includes building construction requirements for grasslands where the vegetation is not managed below a height of 100mm (i.e. grassland that is considered ‘unmanaged’ or ‘natural/undisturbed’). At this point in time it is not possible to accurately map areas of unmanaged grasslands due to limitations with the vegetation datasets currently available. However, there is a need to ensure that buildings in close proximity to such areas are constructed appropriately.

To ensure that unmanaged grasslands are appropriately taken into consideration, DFES and local governments are strongly encouraged to advise OBRM of areas of unmanaged grassland they consider to present a bushfire hazard and wish to have identified as such in the bushfire-prone area dataset.

7.4  Precautionary Principle

The decision maker will need to apply the precautionary principle in identifying bushfire-prone vegetation. There may be situations where additional information becomes available during the verification of the draft data/map bushfire-prone vegetation, where the precautionary principle should be applied if doubt exists.

7.5  Bushfire-Prone Buffer

Once the consolidated bushfire-prone vegetation dataset has been determined, a 100 metre bushfire-prone buffer will be created by Landgate around the bushfire-prone vegetation.

Buffering of the bushfire-prone vegetation may create overlapping polygons. Where two or more buffers overlap, they shall be merged to form a single polygon.

The bushfire-prone area, which is comprised of the bushfire-prone vegetation and the bushfire-prone buffer, will be displayed in accordance with Section 8 of this Standard.

Appendix 1 – Vegetation Key

Pictorial Example of Vegetation

Vegetation Classifications
(AS 3959-2009 Construction of buildings in bushfire-prone areas) / Vegetation Type / Bushfire-Prone Vegetation / Application of ‘Precautionary Principle’
(refer to section 7.4) /

Vegetation Example

a.  Forest / Tall open forest
Tall woodland
Open forest
Low open forest
Pine Plantation / Yes / Image is coming soon!
b.  Woodland / Woodland
Open woodland
Low woodland
Low open woodland
Open shrubland / Yes / Isolated clumps of trees maybe possible BPV if unmanaged grasslands flammability changes due to ephemeral grass growth following above-normal rainfall events. / Image is coming soon!
c.  Shrubland / Closed heath
Open heath
Low shrubland / Yes / Isolated clumps of shrubs maybe possible BPV if unmanaged grasslands flammability changes due to ephemeral grass growth following above-normal rainfall events. / Image is coming soon!
d.  Scrub / Closed scrub
Open scrub / Yes / Image is coming soon!
e.  Mallee / Mulga / Tall shrubland / Yes / Image is coming soon!
f.  Rainforest / Tall closed forest
Closed forest
Low closed forest
Fernland / No / Vegetation may vary due to changing weather conditions, requires monitoring with consideration to climate change. / Image is coming soon!
g.  Grassland / Low open shrubland
Hummock & grassland
(e.g. spinifex, porcupine)
Savannah grasslands
Closed tussock grassland
Tussock grassland
Open tussock
Sparse open tussock
Open herbfield
Sparse open herbfield / Yes / Flammability may change due to ephemeral grass growth following above-normal rainfall events or none/inadequate management/maintenance.
Woodland species intermixed with grasses increases potential for spotting. / Image is coming soon!
h.  Bare areas / Freshwater lakes
Mud flats
Rock outcrops
Salt lakes
Salt affected vegetation (e.g. Forbland) / No / If possible to isolate this vegetation type from surrounding BPV, it is likely that vegetation in between rocks within the outcrop is BPV. / Image is coming soon!
i.  Isolated areas / Chenopod shrubs
Clumps of shrubs
Clumps of trees
Samphire shrubs / Yes / If unmanaged, flammability may change due to ephemeral grass growth following above-normal rainfall events.
Vegetation greater than 1 hectare in size and greater than 20 metres in width shall be considered as bushfire-prone. / Image is coming soon!
j.  Wetlands / Sedgeland / No / Vegetation may vary due to changing weather conditions, requires monitoring with consideration to climate change. / Image is coming soon!
k.  Grasslands (Managed) / Golf Course*
Road Verge*
Town Parks*
Crop
Sown pasture / No / Grass, whether exotic or native, which is regularly maintained at or below 100 mm. Grassland, managed in this minimal fuel condition.
*Unmanaged vegetation greater than 1 hectare in size and greater than 20 metres in width (e.g. bushland within a golf course) shall be considered as bushfire-prone. / Image is coming soon!

[1] AS3959-2009: Construction of buildings in bushfire-prone areas, Standards Australia, 2009, p. 15-16.