THE PALMER GROUP - busselton.wa.gov.au · The south west of Western Australia has a Mediterranean...

PREPARED FOR THE PALMER GROUP MAY 2015

14154. VERSION B

Carbunup Hamlet Bushfire Hazard Assessment

DOCUMENT CONTROL

JOB NO.

Issue Date Issue Details Author Checked Approved

A 24/04/2015 Draft GL

B 12/05/2015 Note regarding plantations GL

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TABLE OF CONTENTS

1 INTRODUCTION ............................................................................................................... 1

2 EXISTING CONDITIONS .................................................................................................. 2

2.1 General ................................................................................................................... 2 2.2 Climate .................................................................................................................... 2 2.3 Vegetation ............................................................................................................... 4

3 POLICY FRAMEWORK ..................................................................................................... 6

3.1 Bushfire Management ............................................................................................. 6 3.2 Planning For Bush Fire Protection Guidelines ........................................................ 6 3.3 Australian Standard AS3959 (2009) ....................................................................... 7 3.4 Local Planning Policy No 9 ..................................................................................... 8 3.5 Fire Break and fuel reduction Notice ....................................................................... 9

4 HAZARD ASSESSMENT ................................................................................................ 10

5 CONCLUSION ................................................................................................................. 12

FIGURES Figure 1 Location Plan ............................................................................................................... 1 Figure 2 Aerial Plan ................................................................................................................... 3 Figure 3 Contour Plan ................................................................................................................ 3 Figure 4 Vegetation ................................................................................................................... 5 Figure 5 Council Bushfire Prone Mapping ................................................................................. 8 Figure 6 Bushfire Hazard ......................................................................................................... 11

TABLES Table 1 Land Details .................................................................................................................. 2 Table 2 Vegetation Descriptions ................................................................................................. 4

JOB NO. | REPORT | CLIENT CARBUNUP HAMLET | 1

1 INTRODUCTION

Town Planning Management Engineering Pty Ltd trading as Calibre Consulting (Aust) has been engaged to prepare a Bushfire Hazard Assessment of the site of the proposed Carbunup Hamlet. The subject land is located on Wildwood Road approximately one kilometre west of Bussell Highway and the Carbunup townsite as shown in Figure 1. This report has been prepared to demonstrate that appropriate regard will be given to Planning for Bush Fire Protection (2010) in the design and development of the subdivision. The aim is to ensure that bush fire hazards are considered at all stages of the planning process so as to avoid increased fire risk to life and property through inappropriately located or designed land use and development.

Figure 1 Location Plan

14154 | Bushfire Hazard Assessment | Palmer Group CARBUNUP HAMLET | 2

2 EXISTING CONDITIONS

2.1 GENERAL

The existing conditions of the site and the surrounding area are shown in Figure 2. The subject land has an area of approximately 115 hectares and is comprised of multiple freehold allotments, crown reserves and road reserves as shown in Table 1. It bounded by Lewis Road on the western boundary and R38582 on the eastern boundary. Lennox Road is an unconstructed road reserve which bisects the site. The subject land is relatively flat and has been developed for rural purposes predominantly being broad acre grazing with some plantations and horticulture. There are existing dwellings and improvements on the site. There are areas of remnant vegetation both within and adjoining the subject land.

Table 1 Land Details

Lot Plan Area(ha)

1490 140494 37.018

1 54704 15.453

2 54704 12.136

1575 153333 2.843

Part 115 73357 41.000

Part 334 103664 8.000

Lot 1575 is Crown reserve managed by the City of Busselton for ‘gravel purposes’. Reserve 38582 on the eastern boundary of the site is managed by the City of Busselton for ‘park and recreation’ and has an area of 31 hectares. The topography of the site is shown in Figure 3. There is an elevation of 20m AHD on the corner of Lewis and Wildwood Roads. This increases to 24m AHD in the western portion of Lot 1490 before dropping to 17m AHD in association with the drainage line. It rises to 27m AHD along the southern boundary. The slopes on the site are generally between 2 and 3 %.

2.2 CLIMATE

The south west of Western Australia has a Mediterranean climate with mild wet winters and hot dry summers. The temperature ranges from average maximum of 28.5°C in the hottest months of January and February to an average of 16.3°C in the colder month of July. Busselton has an average annual rainfall of 809mm with the majority falling between May and August (1). During summer there are morning breezes from the south east and southerly breezes in the afternoon. Wind speeds in summer are typically between 20 to 30 kph. January morning breezes tend to be from the south west or south with afternoon breezes generally from either the south or north west.

1 Bureau of Meteorology – Busselton Weather Station


Figure 2 Aerial Plan

Figure 3 Contour Plan


2.3 VEGETATION

A flora and vegetation survey was undertaken by Eco Logic Environmental Services in October 2014. This identified seven native vegetation types (excluding scattered, isolated and planted trees) being:

1 Open Forest of Jarrah (Eucalyptus marginata), (Marri) Corymbia calophylla, Peppermint (Agonis flexuosa) and Sheoak (Allocasuarina fraseriana);

2 Open Forest of Corymbia calophylla, Agonis flexuosa and Eucalyptus patens;

3 Open Woodland of Agonis flexuosa with scattered trees of Melaleuca

4 Woodland/Scattered trees of Agonis flexuosa (planted), *Melaleuca nesophila (planted) and Melaleuca lanceolata;

5 Open Woodland of Agonis flexuosa and Corymbia calophylla;

6 Closed Shrubland of Pteridium esculentum with scattered Corymbia calophylla and Agonis flexuosa;

7 Closed Shrubland of Pteridium esculentum Areas of planted trees include:

Blue gum trees (Eucalyptus globulus)

Olive Trees

Macadamia trees

Mix of planted Eucalyptus species and Peppermint trees

Planted Garden Trees and Shrubs The areas of remnant vegetation have been highly modified through past clearing, stock grazing and general disturbance to be in a Degraded to Completely Degraded condition. The understorey is generally dominated by introduced pasture grasses and herbs, with few native shrubs or groundcover species. The vegetation units are shown on Figure 4. These classifications are described in terms of tree height and canopy coverage in Table 2.

Table 2 Vegetation Descriptions

Classification Tree Height Canopy Coverage

Open Forest 10-30m 30 – 70%

Woodland 10-30m 10 - 30%

Open Woodland 10-30m 2 – 10%

Closed Shrubland 1 – 2m More than 30%

Scattered Trees 10-30m Less than 2%


Figure 4 Vegetation


3 POLICY FRAMEWORK

3.1 BUSHFIRE MANAGEMENT

Draft State Planning Policy 3.7 Planning for Bushfire Risk Management has been advertised by the Western Australian Planning Commission and is considered to be a seriously entertained planning proposal. The draft State Planning Policy 3.7 Planning for Bushfire Risk Management (SPP 3.7) and the revised draft Planning for Bushfire Risk Management Guidelines have been prepared to strengthen bushfire risk management measures in the planning and development process. Specifically, the documents address the land use planning elements arising from the Keelty Inquiry into the Perth Hills Bushfire in February 2011. The key measures in the framework are:

1. Elevating bushfire issues to be addressed in the highest level of planning policy available,

2. Emphasising the need to consider bushfire management measures in strategic level policy documents, and

3. Seeking to achieve the consistent implementation of bushfire risk management measures across the community.

The SPP applies to all planning proposals located in bushfire-prone areas. A bushfire-prone area is an area that is:

Designation on the proposed State Bushfire Prone Maps; or

Identified on a local government bushfire prone map; or

Land within 100m of an area of bushfire-prone vegetation equal to or greater than one hectare. In summary the SPP requires that:

a) Planning or development applications within bushfire-prone areas are to undertake a bushfire hazard assessment, in accordance with the methodology set out in the Planning for Bushfire Risk Management Guidelines;

b) Planning proposals for land that has a bushfire hazard level above low are to comply with the policy measures;

c) Development is to be designed so as to apply construction standards at or between BAL-12.5 and BAL-29. in an Development in an area that has an extreme bushfire hazard level, and/or requires construction standards of BAL-40 or BAL-FZ, will not be supported unless it can be demonstrated that the risk can be reduced; and

d) Any planning proposal or development application to which this policy applies shall be accompanied by a Bushfire Management Plan.

3.2 PLANNING FOR BUSH FIRE PROTECTION GUIDELINES

Planning for Bush Fire Protection (DFES & WAPC - 2010) is the principal reference document in Western Australia for fire management in subdivisions and related development in rural and in urban/rural communities. It promotes five key principles which are summarised below:

Principle 1 Bush fire hazards must be considered in planning decisions at all stages of the planning

process to avoid increased fire risk to life and property through inappropriately located or designed land use and development.

Principle 2 Local governments are to identify bush fire hazard levels in their structure plans, local planning

strategies and local planning schemes, based on the bush fire hazard assessment methodology in the guidelines.

Principle 3 Subdivision and development in areas with an extreme bush fire hazard level or a bush fire

attack level between BAL- 40 and BAL- FZ, is to be avoided unless specific fire protection requirements can be implemented to the satisfaction of the WAPC, DFES and/or the local government.


Principle 4 In areas with an extreme bush fire hazard level where more intensive subdivision/development is considered unavoidable, permanent hazard reduction measures need to be implemented to reduce the hazard level to low or moderate or bush fire attack levels between BAL- Low and BAL- 29.

Principle 5 Structure plans, subdivision and development in areas with a moderate to extreme bush fire hazard

level needs to be supported by an assessment of the bush fire risk and compliance with the performance criteria and acceptable solutions set out in these guidelines.

The guidelines contain a set of performance criteria and acceptable solutions that new subdivision and developments are required to meet in bush fire prone areas. The main elements relate to:

1.0 Location:- hazard rating.

2.0 Vehicular access:- two access routes; public road design; cul-de-sacs; Battleaxes; private driveways; emergency accessways; fire access routes; gates; firebreaks and signs.

3.0 Water supply:- reticulated areas; non reticulated areas; and dams.

4.0 Siting of development:- hazard separation zones; AS3959 construction standards; building protection zones; and shielding.

5.0 Design of development:- compliant and non compliant development.

3.3 AUSTRALIAN STANDARD AS3959 (2009)

AS3959 Construction of Building in Bush Fire Prone Areas (2) provides measures for improving the ability of buildings to withstand burning debris, radiant heat and flame contact during a bush fire. The lower the separation distance from bushfire prone vegetation, the higher the standard of construction is required for buildings. The construction requirements relate to:-

Subfloor Supports;

Floor;

External Walls;

External Elements and Doors

Roofs;

Verandas, Decks, Steps; and

Water and gas pipes. The Standard contains six Bushfire Attack Levels (BAL) categories as follows:

BAL Low The risk is considered to be very low and does not warrant any specific construction requirements.

BAL 12.5 The risk is considered to be low but there is still a risk of ember attack.

BAL 19 The risk is considered to be moderate. There is risk of ember attack and burning debris by wind borne embers and a likelihood of exposure to radiant heat.

BAL 29 The risk is considered to be high. There is an increased risk of ember attack and burning debris by wind borne embers and a likelihood of exposure to an increased level of radiant heat.

BAL 40 The risk is considered to be very high.

BAL FZ The risk is considered to be extreme.

2 Standards Australia (2009) AS 3959 – Construction of Buildings in Bush Fire Prone Areas. Sydney. Standards Australia International Ltd.


3.4 LOCAL PLANNING POLICY NO 9

Council adopted Local Planning Policy No 9 Environment and Heritage Conservation Policy in 2010. This was subsequently amended in 2013 to include bushfire provisions and local bushfire prone mapping. Clause 2.1 of the Policy stipulates that any amendment on bushfire prone land shall be accompanied by a bush fire hazard assessment consistent with guidance statement A1 of the Guidelines, and, depending on the findings of that assessment and the nature of the proposal, may need to be accompanied by a fire management plan. The Policy also varies the provisions of the Guidelines by requiring:

A 25m building protection zone;

A minimum Bushfire Attack Level rating of BAL19;

A public road or, where that is not practicable, fire service access route shall be provided around the perimeter (either on, or in close proximity to, the boundary of the site) of all subdivisions,

All fire service access routes to be provided as a reserve for bush fire protection and pedestrian access, with a minimum width of 8.0 metres and vested with the City at time of subdivision; and

That emergency access ways are not greater than 100 metres in length unless they are designed as fire service access routes.

Figure 5 is an estimated extract from the Council’s mapping.

Figure 5 Council Bushfire Prone Mapping


3.5 FIRE BREAK AND FUEL REDUCTION NOTICE

The principal method for implementing fire measures on developed land is through Council’s annual Hazard Reduction Notice (Firebreak Order) which requires the occupiers of all land to undertake fire prevention work as set out in the notice. The Notice generally requires that:

1 For urban residential land which is less than 2,024 sqm in area, all hazardous materials must be removed from the land except for live standing trees. Other vegetation is to be maintained to a maximum height of 10 centimetres and trees shall be pruned to provide a setback of 3m from all buildings.

2 For urban residential land which exceeds 2,024 sqm in area a 3m wide mineral earth firebreak is to be constructed inside of all boundaries.

3 A 20m wide building protection zone must be provided in bush fire prone areas unless varied by the provisions of a fire management plan.

The building protection zone is also to:

Be 25m wide for all buildings constructed after 2011;

Located within the lot boundary;

Have fuel loads maintained at 2 tonnes per hectare;

Ensure that the first 5m around all buildings is clear of flammable material;

Reticulated gardens are to be maintained to a maximum height of 500mm;

Woodpiles are to be 10m from the dwelling; and

Trees must be pruned to ensure a separation of at least 3m from the eves of all buildings and 5m above the top of the roof.


4 HAZARD ASSESSMENT

The attached bushfire hazard assessment has been prepared base upon the existing site conditions, vegetation and flora report. The bush fire hazard primarily relates to the vegetation on the site, the type and extent (area) of vegetation and its characteristics. Appendix 1 of the Planning for Bushfire Protection Guidelines provides the methodology for determining the bush fire hazard. This classifies vegetation based on tree height and the percentage of canopy cover. The characteristics of the different hazard categories are:- 1 Low hazard areas will generally be:

areas devoid of standing native vegetation (less than 0.25 ha cumulative area);

areas which due to climatic or vegetation (eg rainforest) conditions, do not experience bush fires;

inner urban or suburban areas with maintained gardens and very limited native standing vegetation (less than 0.25 ha cumulative area); or

pasture or cropping areas with very limited native standing vegetation that is a shrubland, woodland or forest.

2 Moderate hazard areas will generally be:

areas containing pasture or cropping areas with slopes in excess of 10°;

open woodlands;

open shrublands;

low shrubs with slopes of less than 10° or flat land; or

suburban areas with some native tree cover. 3 Extreme hazard areas will generally be forests; woodlands or tall shrubs. Figure 6 shows the bush fire hazard rating for the subject land based upon the above classifications.

The uncleared areas within and adjoining the site are classified as having an extreme fire hazard rating; and

The cleared areas are classified as having a low hazard rating. This will occur where the grasslands / paddock area are managed by cropping, grazing or slashing prior to the fire season so that the grasses do not exceed 100mm in height.

The cleared areas which are within 100m of the areas with an extreme or moderate hazard rating are to be assigned a moderate hazard rating to reflect the increased level of risk.

REF NO 14154P

F

E

D

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A Draft GL 15/04/2015

REVISION DESCRIPTION AUTHOR DATE

TME Town Planning Management Engineering Pty. Ltd. trading as Calibre Consulting (Aust) (08) 9791 4411 calibreconsulting.co

FIGURE 6 CARBUNUP RIVER BUSHFIRE HAZARD ASSESSMENT

COPYRIGHT

THIS DOCUMENT IS AND SHALL REMAIN THE PROPERTY OF CALIBRE CONSULTING (AUST). THE

DOCUMENT MAY ONLY BE USED FOR THE PURPOSE

FOR WHICH IT WAS COMMISSIONED AND IN ACCORDANCE WITH THE TERMS OF ENGAGMENT

FOR THE COMMISSION, UNAUTHORISED USE OF THE DOCUMENT IN ANY FORM IS PROHIBITED.

THIS PLAN HAS BEEN PREPARED FOR PLANNING PURPOSES AREAS, CONTOURS AND DIMENSIONS

SHOWN ARE SUBJECT TO SURVEY.

LEGEND Subject Land

Extent of Mapping (100m past the Subject Land)

Extreme Hazard Rating Moderate Hazard Rating Moderate Hazard Rating (Land within 100m of land with a Moderate or Extreme hazard rating) Low Hazard Rating Scale

L

NOTES Hazard mapping prepared in accordance with the methodology contained in Appendix 1 of Planning for Bush Fire Protection Guidelines (2010). The hazard mapping is required to extend for 100m past the property boundary. Based upon site inspections; aerial photography and flora survey.

LOW HAZARD

areas devoid of standing native vegetation;

inner urban or suburban areas with maintained gardens and limited native vegetation; or

pasture or cropping areas with very limited native vegetation.

MODERATE HAZARD

areas of pasture or cropping areas with slopes in excess of 10°;

open woodlands and open shrublands;

low shrubs with slopes of less than 10° or flat land;

suburban areas with some native tree cover.

EXTREME HAZARD

forests;

woodlands; or

tall shrubs.

The draft 2014 Bushfire Risk Management Guidelines Appendix 2 designates that land with a “low” hazard rating which is located within 100m of land with an “extreme” or “moderate” hazard rating shall be classified as having a “medium” hazard rating.

0 100m

L

L

L

L

Note: The proponent intends harvesting the bluegum plantation prior to Hamlet development - thereby minimising the bushfire hazard


5 CONCLUSION

In general a bush fire hazard can be mitigated by:

Reducing vegetation fuel loads;

Maintaining fire breaks;

Providing adequate separation distances between buildings and bush fire fuel areas; and

Ensuring that new buildings in bush fire prone areas are built in accordance with Australian Standard 3959 Construction of Buildings in Bushfire-Prone Areas (AS 3959).

As the majority of the subject land has a moderate or extreme bushfire hazard rating it is necessary under both SPP 3.7 and Council’s Policy to ensure that permanent hazard reduction measures be implemented to ensued that development only occurs in areas with a to low or moderate hazard rating or bush fire attack levels between BAL- Low and BAL- 29. As the subject land is defined as being bushfire prone it is necessary for any structure plan, amendment or subdivision application to comply with the provisions of State Planning Policy 3.7 Planning for Bushfire Risk Management and specifically that:

a) All subdivision applications, Scheme amendments or structure plans must be accompanied by a bushfire management plan. This is in order to ensure that appropriate fire management measures are incorporated into the design and any statutory provisions.

b) All dwellings will be required to be constructed in accordance with AS3959 Construction of Buildings in Bushfire Prone Land.

c) All building applications must be accompanied by a BAL assessment. Where bushland areas are intended to be retained or where revegetation and landscaping occurs it will be necessary to provide appropriate separation distances to the development. Where these distances are less than 100m then residential development will have to be constructed in accordance with AS3959 Construction of Buildings in Bushfire Prone Areas. It is noted that the BCA only applies AS3959 to the following building classes:

Class 1(a) - single dwelling;

Class 1(b) - a boarding house, guest house, hostel or 4 or more single dwellings located on one allotment and used for short-term holiday accommodation;

Class 2 - a building containing 2 or more sole-occupancy units each being a separate dwelling;

Class 3 - a residential building, other than a building of Class 1 or 2, which is a common place of long term or transient living for a number of unrelated persons; and

Class 10 - a non-habitable building being a private garage, carport, shed, or the like. The BCA does not apply AS3959 to other classes including commercial or industrial buildings. Where such buildings are proposed in the development and if they are closer than 100m to classified bushfire prone vegetation then it will be necessary for the amendment or structure plan to provide a statutory means of applying bushfire construction standards. There are two areas of remnant bushland immediately adjacent to the site being:

Reserve 20554 on the north western corner of the subject land; and

Reserve 38582 on the eastern boundary. Reserve 38582 (Carbunup Reserve) is subject to a formal management plan as it has very high regional conservation values. It has an area of approximately 31 hectares. The management plan notes that the reserve poses a significant threat to the town’s residents and their property in the event of an unplanned, summer wildfire.


It is recommended that any amendment or structure plan for the subject land:

1) Incorporate appropriate bushfire protection measures in accordance with SPP3.7, the Planning for Bushfire Protection Guidelines and Council’s Local Planning Policy.

2) That the fire management plan be prepared in conjunction with any structure plan to ensure that the spatial requirements for bushfire management are included in the design.

3) That any subdivision be designed to ensure that development can be provided with a maximum BAL29 rating.

4) That the design of public open space areas and landscaping recognise fire management requirements including the provision of hazard separation zones and low threat vegetation as required by any fire management plan.

5) That a strategic low fuel zone and increased separation distance be provided along the eastern boundary of the development adjacent to Reserve 38582.

6) Include statutory provisions to ensure that any non residential buildings are developed with appropriate bushfire construction measures as the BCA only applies AS3959 to Class 1, 2, 3 and 10 buildings.

7) That the inclusion of any vulnerable or high risk land uses within the development will require detailed fire management provisions.

JOB NO. | REPORT | CLIENT CARBUNUP HAMLET | 14

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THE PALMER GROUP - busselton.wa.gov.au · The south west of Western Australia has a Mediterranean...

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