home | city of fremantle - 170239 rocky bay & cypress hill ......north fremantle city of...

BPP Group Pty Ltd | ABN: 39 166 551 784

1/42 Victoria Street Midland WA 6056

PO Box 3489 Midland WA 6936

08 6477 1144 | [email protected]

Rocky Bay Reserve & Cypress HillBushfire Risk Management Report

North Fremantle

City of Fremantle

Project Number: 170239

Assessment Date: 28 April 2017

Report Date: 13 June 2017

170239 Rocky Bay & Cypress Hill Bushfire Risk Management Report Final V1.0

©2016 BPP Group Pty Ltd Page | 1

Plan Details

Plan Version Submitted to Submitted Date

Draft v1.0 Landowner 27-May-17

Plan Version Amendment Record Submitted Date

v1.1Draft report to be presented to Public consultation, City of Fremantleand DPAW

13-Jun-17

v1.2 Final Report after review and integration of comments 19-Jun-17

Author/Assessor Bushfire Planning and Design (BPAD) Accreditation Signature

Alex Aitken Level 2 Bushfire Planning Practitioner BPAD37739

BPP Group Pty Ltd t/a Bushfire Prone Planning ACN: 39 166 551 784

Author/Approved Bushfire Planning and Design (BPAD) Accreditation Signature

Kathy NastovLevel 3 Bushfire Planning and Design

PractitionerBPAD27794

BPP Group Pty Ltd t/a Bushfire Prone Planning ACN: 39 166 551 784



Contents

1 INTRODUCTION ...................................................................................................................... 4

2 SITE DETAILS AND BUSHFIRE CONTEXT.................................................................................... 5

DOCUMENT CONSTRUCTION AND CONTENT ........................................................................................6

3 METHODOLOGY...................................................................................................................... 8

VEGETATION IDENTIFICATION AND CLASSIFICATION ...............................................................................8METHOD 2 DETAILED BUSHFIRE ATTACK LEVEL (BAL)...........................................................................8BUSHFIRE ATTACK LEVEL (BAL) ASSESSMENT – BAL CONTOUR MAP ......................................................9

4 ASSESSMENT OF BUSHFIRE RISK............................................................................................ 11

VEGETATION CLASSIFICATION .........................................................................................................11METHOD 2 BAL CONTOUR INTERVAL CALCULATIONS..........................................................................18

5 BUSHFIRE RISK MANAGEMENT RECOMMENDATIONS ........................................................... 23

VEGETATION MANAGEMENT ..........................................................................................................24BUSHFIRE RISK MANAGEMENT RECOMMENDATIONS BY ZONE ..............................................................25

5.2.1 Management Zone 5: Cypress Hill ......................................................................................255.2.2 Management Zone 5: Rocky Bay Cliff Top (also known as Rocky Bay Heritage Trail)........285.2.3 Management Zone 6: Rule Park..........................................................................................305.2.4 Management Zone 6: Rocky Bay Principal Shared Path.....................................................315.2.5 Management Zone 7: Rocky Bay Cliffs and Slopes .............................................................335.2.6 Management Zone 7: Waugyl Cave....................................................................................345.2.7 Vegetation Area 8- recommendations................................................................................35

6 REFERENCES ......................................................................................................................... 36

7 APPENDICES ......................................................................................................................... 37



Appendices

APPENDIX 1.................................................................................................................................. 37

METHODS 2 BAL CALCULATIONS AND ASSUMPTIONS .....................................................................................37

APPENDIX 2.................................................................................................................................. 49

BUSHFIRE ATTACK LEVEL ASSESSMENT METHODOLOGY ...................................................................................49

APPENDIX 3.................................................................................................................................. 51

VEGETATION CLASSIFICATION EXCLUSIONS (AS 3959-2009 S2.2.3.2) .............................................................51

APPENDIX 4.................................................................................................................................. 52

ASSET PROTECTION ZONES (APZ) - DESCRIPTION, ESTABLISHMENT, MAINTENANCE AND STANDARDS......................52

DisclaimerThe measures contained in this Bushfire Management Plan are considered to be minimum standards and they do notguarantee that a building will not be damaged in a bushfire. This is substantially due to the unpredictable nature andbehaviour of fire and extreme weather conditions. Additionally, the achievement of and level of implementation ofbushfire management measures will depend, among other things, on the actions of the landowners or occupiers overwhich Bushfire Prone Planning has no control.

All surveys, forecasts, projections and recommendations made in this report associated with the project are made in goodfaith on the basis of information available to Bushfire Prone Planning at the time.

All maps included herein are indicative in nature and are not to be used for accurate calculations.

Notwithstanding anything contained therein, Bushfire Prone Planning will not, except as the law may require, be liablefor any loss or other consequences (whether or not due to the negligence of their consultants, their servants or agents)arising out of the services provided by their consultants.

Copyright NoticeThe format and certain content of this work is copyright. Apart from any use permitted under the Copyright Act 1968,none of these parts may be reproduced by any process, nor may any other exclusive right be exercised, without thepermission of BPP Pty Ltd of PO Box 3489 Midland WA 6936. This work was made in 2016.

As this material is in an electronic format, the removal or alteration of this material is prohibited by the Copyright Act incertain circumstances.



1 Introduction

The City of Fremantle commissioned Bushfire Prone Planning to undertake a bushfire risk assessment

utilising the detailed method for determining the Bushfire Attack Level (BAL) from AS3959-2009

(Method 2) and to prepare an associated Bushfire Management Plan (Plan) for Rocky Bay Reserve and

Cypress Hill, North Fremantle. These requirements follow on from the development and review of the

North Fremantle Foreshore Vegetation Management (NFFVM, 2016), prepared by Ecoscape and Lush

Fire and Planning in 2016.

Through the development of the NFFVM (2016) it was determined that minor fires of negligible

consequence have historically occurred on the site, however the areas of Rocky Bay Reserve and

Cypress Hill are subject to an Extreme Bushfire Hazard rating based on the Bushfire Hazard Level

Mapping as per the Guidelines for Planning in Bushfire Prone Areas v1.1 (WAPC 2017). It is important

to better understand this risk through more detailed bushfire behaviour modelling and apply

appropriate mitigation measures where feasible with consideration of the determined risk factors.

This Plan sets out the approach for assessing the risk utilising a Method 2 BAL assessment, taking into

consideration the complexities of the site of Rocky Bay Reserve and Cypress Hill including the narrow

width of vegetation along the Rocky Bay Reserve and associated slopes greater than 20 degrees. The

aims and objectives of this Plan are to provide recommendations for bushfire risk management based

on this detailed methodology, and include:

• determining or indicating the Bushfire Attack Levels (BAL’s) that existing Lots and buildings,

within the subject site, are subject to

• using methodology 2 according to AS3959 –2009 to determine the BAL’s including

• providing consideration of the impact on houses adjacent to the subject area both before and

after mitigation recommendations have been implemented;

• providing consideration for ecological value of the site;

• recommendations species for revegetation within the asset protection zone with reference to

the draft North Fremantle Foreshore Vegetation Management (2016);

• separating the recommendations according to the following vegetation management zones;

• Management Zone 5: Cypress Hill;

• Management Zone 5: Rocky Bay Cliff Top (also known as Rocky Bay Heritage Trail);

• Management Zone 6: Rule Park;

• Management Zone 6: Principal Shared Path;

• Management Zone 7: Rocky Bay Cliffs and Slopes; and

• Management Zone 7: Waugyl Cave.

• Identifying the landowner responsibilities for both the reserve land (Rocky Bay Reserve and

Cypress Hill) and the adjacent landowners.

This Plan has been prepared in accordance with all relevant legislation, regulations, policies and

guidelines as outlined in Section 2.1



2 Site Details and Bushfire Context

The subject site is the open space reserve of Rocky Bay adjacent to the Swan River, north of HarvestRoad and south of the Town of Mosman Park boundary, adjacent to Westmeath Street, NorthFremantle, which includes the site of Cypress Hill (see Figure 2.1).

The North Fremantle foreshore is a multi-use site, providing the community with recreational uses aswell as hosting areas of ecological, historical and cultural significance. The balance of managing the sitefor these uses and for its significant values are challenging, with bushfire management of the site beingone of the greatest challenges. Bushfire management is typically focussed on managing vegetation toreduce the impact of bushfire on ecological, cultural, heritage and other assets including neighbouringproperties in the area. The management of bushfire risk through vegetation control is complicated bythe extreme slopes of the cliff areas. Furthermore, the area has significant cultural heritage sites suchas caves that requires due consideration in the landscape. The bushfire risk management measuresrequired to reduce the risk to an acceptable level are detailed in this Plan, with the focus on managingthis land use balance.

The site has been broken up into Management Zones as defined in the NFFVM (2016). As relevant tothis study site, the following Management Zones are discussed in this Plan (Figure 2.2);

• Management Zone 5: Cypress Hill;

• Management Zone 5: Rocky Bay Cliff Top (also known as Rocky Bay Heritage Trail);

• Management Zone 6: Rule Park;

• Management Zone 6: Rocky Bay Principal Shared Path;

• Management Zone 7: Rocky Bay Cliffs and Slopes; and

• Management Zone 7: Waugyl Cave.

Bushfire Hazard Level mapping contained within the NFFVM (2016) has indicated an Extreme bushfirerisk for both the Rocky Bay Reserve and Cypress Hill. This is based on Bushfire Hazard Level mappingrequirements contained within the Guidelines for Planning in Bushfire Prone Areas and influenced by anumber of factors, namely vegetation type. Historically, numerous small fires have occurred along thereserve, either purposely lit or ignited from discarded cigarettes, however none of the occurrences areknown to have caused significant damage (North Fremantle Foreshore Management Plan 2013).Bushfire risk is a concern to the local community as covered in the North Fremantle ForeshoreManagement Plan (2013) during the community consultation process.

The subject area is comprised of Crown Land. Cypress Hill is Freehold tenure that is currently vestedwith the WAPC however, it is proposed that the City of Fremantle request a Management Order overCypress Hill to manage the site for conservation and recreation (NFFVM (2016). In accordance withSection 12 of the Swan and Canning Rivers Management Act 2006 the Department of Parks and Wildlifehave shared management responsibility for the Riverpark shoreline 2m above and below the highwater mark measured horizontally above the surface of the land.

Parks and Wildlife are the statutory approval authority for development in the Swan and Canning RiversDevelopment Control Area as prescribed in the Swan and Canning Rivers Management Act 2006. TheCity of Fremantle are required to apply for a permit to undertake fire hazard reduction works and



vegetation removal within the Rocky Bay Reserve in accordance with Swan and Canning RiversManagement Regulations 2007

Document Construction and Content

This report has been prepared with consideration of the following policies, guidelines and standardsand has been prepared within the parameters for interpretation of the document as outlined below;

Relevant Policies, guidelines and standards

• Overall Fuel Hazard Assessment Guide, 4th Edition July 2010 (Department of Sustainability and

Environment, Victoria 2010)

• AS3959-2009 Construction of buildings in bushfire-prone areas (Standards Australia, 2009)

• Visual Guide for Bushfire Risk Assessment in WA (Western Australian Planning Commission,

February 2016)

• Corporate Policy Statement No.42: Planning for land use, development and permitting affecting

the Swan Canning Development Control Area (Department of Parks and Wildlife and Swan River

Trust, 2016)

• City of Fremantle Fire Prevention (Firebreak Notice)

• Guidelines for Preparing a Bushfire Risk Management Plan, November 2015 (Department of

Fire & Emergency Services)

• The State Planning Policy No. 3.7: Planning in Bushfire Prone Areas (SPP 3.7) (Western

Australian Planning Commission and Department of Planning, 2015)

• Guidelines for Planning in Bushfire Prone Areas (Western Australian Planning Commission v1.1,

2017)

Parameters for interpretation

This report is to be read in conjunction with the NFFVM (2016). This report should be reviewed 5 yearlyby the City of Fremantle for currency and to monitor ongoing requirements.

The requirement for a Local Government to undertake a bushfire risk assessment and prepare anassociated Bushfire Risk Management Pan falls under the State Hazard Plan for Fire (Westplan Fire).SPP 3.7 is not an applicable policy to be utilised in the preparation of this report as SPP 3.7 is solely forthe purposes of planning and development (under the Planning and Development Act, 2005). Certainelements of the Policy and the respective Guidelines however have assisted in the development of thisreport.The Guidelines for Preparing a Bushfire Risk Management Plan (DFES, 2015) are applicable to a broaderstudy area, being a whole Local Government area, rather than a specific site such is this case. Again,elements of these guidelines have been adopted and utilised in this report to best deliver the requiredoutcomes.

THOMPSONRD

RULE ST

COVENTRY PDECOVENTRY PDE

HARVEST RDAINSLIE RD

THOMPSON RD

BURFORD PL

ALFRED RD

FOUNDRY CT

KEELPL

STAPLES ST

CORKHILL ST

CHRISTINA PDE

ALFRED RD

BURFORD PL

PHYLLIS ST

PAMMENT ST

BINNS CT

EUCLA CT

HIGHAM RD

STAPLES ST

LETITIA RD

WESTMEATH ST

___________ LEGEND ___________

Subject LotsOther Lots

Management Zones (NFFVM, 2016)Cypress Hill / Rocky Bay Cliff TopRocky Bay Cliffs and SlopesRocky Bay Principal Shared Path

Disclaimer and Limitation: This map has been prepared for bushfire management planning purposes only. All depicted areas, contours and any dimensions shown are subject to survey. Bushfire Prone Planning does not guarantee that this map is without flaw of any kind and disclaims all liability for any errors, loss or other consequence which may arise from relying on any information depicted.

Lot 447 on Plan 217041 - Reserve 7077Lot 511 on Plan 23640 - Reserve 46369Lots 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30 on Plan 4461North Fremantle

Figure 2.1Subject Site

0 25 50 75 100 125 150 175 200

Metres

_________ SCALE (A3) _________

B I B R AB I B R AL A K EL A K E

SOUTHNEDLANDS

WEST WARD

BICTON

CORBETT

NORTHFREMANTLE

APPLECROSSMOSMAN PARK

MOSMAN PARK

COTTESLOE

FREMANTLE

__________ LOCALITY __________

pMap created on: 13/06/2017Map compiled by: Russell Wornes

Coordinate System: GDA 1994 MGA Zone 50Projection: Universal Transverse Mercator Units: Metre

Aerial Image: Landgate Feb 2017

Rocky Bay Reserve &

Cypress Hill



3 Methodology

The bushfire risk assessment of the North Fremantle Foreshore is derived from the DFES bushfire pronearea map (May 2017) and the NFFVM (2016) with the areas identified to be assessed for bushfire riskwas undertaken using the methodology detailed below.

Vegetation Identification and Classification

All vegetation within 100 metres of the subject site has been identified and classified or excluded and

presented in Table 4.1. This has been done in accordance with AS 3959-2009 and reference to the

Visual Guide for Bushfire Risk Assessment in WA (WAPC February 2016).

The vegetation has been assessed as it will be in its mature state and where deemed appropriate, in

its unmanaged state. The areas of classified vegetation that will determine bushfire risk are defined on

the topography and vegetation map Figure 4.1. Representative photos of each vegetation area is

presented in Section 4.1.

Certain areas and vegetation may be assessed as ‘low threat or non-vegetated’. These are to be

excluded from classification and are therefore rated BAL-LOW. They must be managed to maintain the

specifications set out in AS3959-2009 s2.2.3.2 in perpetuity (refer to Appendix 3 ‘Vegetation

Classification Exclusions’).

In assessing vegetation for bushfire threat, consideration must be given to possible future vegetation

changes likely on the site that is being assessed and in particular those that would have the potential

to increase the bushfire risk. This may be due to growth of existing vegetation or growth of planned

landscape plantings, including future roadside and foreshore re-vegetation. In particular, there must

be careful consideration of the creation of vegetation corridors where they join offsite vegetation and

may provide a route for fire to enter an area of development.

Method 2 Detailed Bushfire Attack Level (BAL)

AS 3959-2009 Construction of Buildings in Bushfire Prone Areas, provides the methodology for

determining the potential radiant heat flux from a bushfire with respect to vegetation type, slope and

climatic conditions. The bushfire attack assessment mathematical model used comprises two sub-

models - one that models bushfire behaviour (to calculate flame length) and the other that models

radiation (to predict the radiation level at a given distance). It provides two methods of using the model

– BAL Method 1 and BAL Method 2. This bushfire risk management plan has utilised BAL Method 2 to

calculate the potential/indicative radiant heat flux impacting on assets and infrastructure within the

bushfire prone areas of the NFFVM (2016).

The Method 1 assessment procedure is a simplified procedure that limits the number of inputs

required, applies various default values and focuses on radiant heat. The outcome is a streamlined

process that provides a useful but coarse and conservative result. The Method 2 assessment procedure



is a more rigorous assessment and involves the use of engineering analysis and judgement. It considers

a site’s specific situation and improves on the accuracy of the bushfire risk assessment.

These key variables in the Method 2 BAL calculations are the Fire Danger Index; Vegetation

Classification/Fuel Loads/Height; Effective Slope; Site Slope; Separation Distance; Flame Width; and

Elevation of Receiver.

The primary limitations that remain with the Method 2 assessment procedure are:

1. Method 2 can only be used where the effective slope under the classified vegetation is no more

than 300 down slope and the slope of the land between the site and the classified vegetation is

no more than 200, regardless of slope type; and

2. Radiant heat shielding from the surrounding landscape is not considered (i.e. from physical

structures/landforms).

The Method 2 BAL assessment has considered the steep slopes associated with the river cliff lines and

the narrow vegetation corridors between the existing residential areas and water line. As a result of

the narrow vegetation corridors, a potential worst case scenario has been utilised in the calculations

for the vegetation areas with respect to the potential impact on the residential lots. The longest

potential direct fire run with the estimated effective slope calculated was from 1m contour data. The

use of the short fire run calculations to estimate head fire width as opposed to the presumed the

standard 100m width used in the Method 1 BAL calculation was a major input into the Method 2 BAL

ratings that feed into the BAL contour map. For further detail on BAL Method 2 calculations and

assumptions utilised see Appendix 1 of this plan.

Bushfire Attack Level (BAL) Assessment – BAL Contour Map

Description and Purpose of the BAL Contour Map

The BAL Contour Map is a scale map of a site which identifies indicative BAL ratings across the

development site and within the immediate surrounding area. The map illustrates potential bushfire

attack levels and radiant heat impacts in relation to any classified vegetation that exist within 150

metres of the assessment area.

BAL Contour Map Interpretation

The contour map will present different coloured contour intervals constructed around the classified

bushfire prone vegetation. These represent the different Bushfire Attack Levels (BAL’s) that exist as the

distance increases away from the classified vegetation. Each BAL represents a set range of radiant heat

flux that can be generated by the bushfire in that vegetation. The width of each shaded contour

interval (i.e. the applicable vegetation separation distances corresponding to a BAL rating) will vary and

is determined by calculations involving vegetation type, fuel structure, ground slope, and climatic

conditions (i.e. the expected fire behaviour). They are unique to a site and can vary across a site.

BAL Contour Map Pre and post Bushfire Risk Management

BAL Contour Maps have been prepared over the subject site to show current BAL ratings, and BAL

ratings post the application of bushfire risk management recommendations as detailed in Section 5 of



this Plan. It was not feasible to prepare a BAL Contour Map- post management for the area of Rocky

Bay Reserve north of the Rule Street Carpark as the recommendations to manage the bushfire risk

would reduce overall bushfire intensity but not be sufficient to reduce the BAL’s on the adjacent

residential lots due to the proximity of the houses to the vegetation.



4 Assessment of Bushfire Risk

Vegetation Classification

The vegetation classification has been based on AS3959-2009 with respect to the bushfire behaviour

of the most appropriate vegetation type and highest potential impact. The following section details the

information and data collected and interpreted from the site visit.

Table 4.1: Vegetation types identified, the applied classification and effective slope

All Vegetation Within 100 metres of the Site

Vegetation

Area

Identified Types (AS3959) or Description if

‘Excluded’Applied Classification

Effective

Slope Under

Classified

Vegetation

(degrees)

1 Woodland B-05 Class B Woodland 0

2 Closed Scrub D-13 Class D Scrub 0

3 Open Heath C-11 Class C Shrubland 0

4 Open Scrub D-14 Class D Scrub 0


6 Woodland B-05 Class B Woodland 15 (-15)


8 Open Woodland B-06 Class B Woodland 0

Managed areas, parklands, gardens Exclusion 2.2.3.2 (f) -

Note: When more than one vegetation type is present each type is classified separately with the

worst case scenario being applied. The predominant vegetation is not necessarily the worst case

scenario.



Vegetation Area 1 Classification Applied: Class B Woodland

Photo 1a Photo 1b

Photo 1c Photo 1d

Vegetation Area 2 Classification Applied: Class D Scrub

Photo 2a Photo 2b



Vegetation Area 3 Classification Applied: Class C Shrubland

Photo 3a Photo 3b

Vegetation Area 4 Classification Applied: Class D Scrub

Photo 4a Photo 4b


Photo 5a Photo 5b




Photo 6a Photo 6b


Photo 7a Photo 7b


Photo 8a Photo 8b

AREA : 1Class (B) WoodlandEffective slope: 0°

AREA : 2Class (D) Scrub

Effective slope: 0°

AREA : 3Class (C) ShrublandEffective slope: 0°

AREA : 5Class (B) Woodland

Effective slope: >5° to 10°

AREA : 4Class (D) Scrub

Effective slope: 0°









THOMPSONRD

RULE ST


HARVEST RD

AINSLIE RD

THOMPSON RD

BURFORD PL

ALFRED RD

FOUNDRY CT

KEELPL

STAPLES ST

CORKHILL ST

CHRISTINA PDE

ALFRED RD

BURFORD PL

PHYLLIS ST

PAMMENT ST

BINNS CT

EUCLA CT

HIGHAM RD

STAPLES ST

LETITIA RD

WESTMEATH ST

220 0mm

11 55mm

15 m15 m1 10 0mm

1100mm

25 m25 m

2255 mm

11 55 mm

5 m5 m

20 m

20 m

10 m10 m

10 m10 m

11 55 mm

11 00mm

5 m5 m

___________ LEGEND ___________


Classified VegetationClass (B) WoodlandClass (C) ShrublandClass (D) Scrub

E E EExclusion 2.2.3.2



Figure 4.1Topography &Classified Vegetation

0 25 50 75 100 125 150 175 200

Metres

_________ SCALE (A3) _________


SOUTHNEDLANDS

WEST WARD

BICTON

CORBETT

NORTHFREMANTLE


MOSMAN PARK

COTTESLOE

FREMANTLE

__________ LOCALITY __________




Rocky Bay Reserve &

Cypress Hill

STIRL

ING

HWY

THOM

PSON

RD

CHRISTINA PDE

CRAIG ST


PAMMENT ST

MATHIESON AV

LIME

ST

SALUSTRI PL

FOUNDRY CT

STONE ST

BURFORD PL

KEELPL

MCCABE ST

TYRO

NEST

BINNS CT

LESLIE RD

EUCLA CT RULE ST

THE CUTTING

WESTMEATH ST

AREA1

AREA2

AREA3

AREA4

AREA8

AREA9

___________ LEGEND ___________


E EE E Exclusion 2.2.3.2




Figure 4.1aManagement Areas &Vegetation Areas

0 25 50 75 100 125 150 175 200

Metres

_________ SCALE (A3) _________

SOUTHNEDLANDS

WEST WARD

BICTON

CORBETT

NORTHFREMANTLE


MOSMAN PARK

COTTESLOE

FREMANTLE

__________ LOCALITY __________




Rocky Bay Reserve &

Cypress Hill

THOMPSON RD

HARVEST RD

AINSLIE RD

JOHN ST

RULE ST

THOMPSON RD

BURFORD PL

ALFRED RD

HERBERT ST

CORKHILL ST

STAPLES ST

ALFRED RD

PASSMORE AV

FAY ST

BURFORD PL

PHYLLIS ST

WHITE ST

HEVRON ST

EUCLA CT

HIGHAM RDSTAPLES ST

LETITIA RD

TURTON ST

DIRECTION WAY

AREA3

AREA5

AREA4

AREA7

AREA6

AREA8

___________ LEGEND ___________


E EE E Exclusion 2.2.3.2




Figure 4.1bManagement Areas &Vegetation Areas

0 25 50 75 100 125 150 175 200

Metres

_________ SCALE (A3) _________


SOUTHNEDLANDS

BICTON

CORBETT

NORTHFREMANTLE


MOSMAN PARK

COTTESLOE

FREMANTLE

__________ LOCALITY __________




Rocky Bay Reserve &

Cypress Hill



Method 2 BAL Contour Interval Calculations

For the subject site, the vegetation separation distance range that corresponds to each BushfireAttack Level (and represented by Figure 4.2, 4.2a and 4.2b, the BAL Contour Map), has been derivedfrom:

1. An AS3959-2009 Method 2 assessment as per AS3959-2009 Appendix B.

.

Table 4.2: Construction of the BAL contours

Statement of Site Data and ‘Separation Distance Range’ Applied

Vegetation

Area

BAL Assessment Method

Used

Site Data Applied in the BAL

Assessment

Separation Distance Range

Applied/Determined

1

AS3959-2009 Method 2

Refer to Table 4.1 and

Section 4.

A summary of the applied

data is presented in the

appendices for each

relevant Vegetation Area.

The range determined by

Method 2 calculations

and presented in the

appendices for each

relevant Vegetation Area.

2

3

4

5

6

7

Vegetation areas 1 to 4 have been applied an effective slope of 0 degrees. This is due to the slope under

the vegetation (effective slope) being cross slope as it has been assumed that fire will traverse the site

diagonally to the houses rather than parallel (which would assume a short fire run) or perpendicular to

the houses from the bottom of the cliff side (which can’t be modelled as the vegetation here is

discontinuous and greater than 30 degrees slope in many areas), as this bushfire behaviour is unlikely.

Vegetation areas 5 to 7 have been applied variable cross slopes based on potential fire run and worst

case scenario of bushfire impact. The risk of ignition along the river edge is highly unlikely and will be

focussed around areas where people are as has been shown from the historical fire reports.

The main restriction on reducing the risk of bushfire in the area is the steep slopes associated with theRocky Bay area and the narrow width of the vegetation corridors/areas. By completing any mitigationworks as proposed in Section 5 for the areas north of Rule Street Park the vegetation types are notproposed to be modified or separation distances increased due to the potential impact on the erosionof the steep slopes. In the area within Cypress Hill and adjoining areas along the river post mitigation



BAL assessment was completed based on the modification of the vegetation type and therefore areduction in the bushfire intensity and potential impact on the nearby residential lots.

Area 8 has not been included in the BAL contour mapping as it is outside of the Scope of Works for theNorth Fremantle Foreshore plan, however recommendations for management of this area are detailedin Section 5 of this Plan.

For further technical details on the BAL Method 2 calculations and assumptions utilised see Appendix

1.

STIRL

ING

HWY

THOM

PSON

RD

CHRISTINA PDE

CRAIG ST


PAMMENT ST

MATHIESON AV

LIME

ST

SALUSTRI PL

FOUNDRY CT

STONE ST

BURFORD PL

KEELPL

MCCABE ST

TYRO

NEST

BINNS CT

LESLIE RD

EUCLA CT RULE ST

THE CUTTING

WESTMEATH ST

___________ LEGEND ___________

Subject LotsOther Lots Area of Interest - 150m extent

Bushfire Attack LevelsVegetation edge (Indicative only)BAL FZ (Indicative only)BAL 40 (Indicative only)BAL 29 (Indicative only)BAL 19 (Indicative only)BAL 12.5 (Indicative only)BAL LOW (Indicative only)


Figure 4.2BAL Contour (Method 2) Map


0 25 50 75 100 125 150 175 200

Metres

_________ SCALE (A3) _________

SOUTHNEDLANDS

WEST WARD

BICTON

CORBETT

NORTHFREMANTLE


MOSMAN PARK

COTTESLOE

FREMANTLE

__________ LOCALITY __________




Rocky Bay Reserve &

Cypress Hill

THOMPSONRD

HARVEST RD

AINSLIE RD

JOHN ST

RULE ST

THOMPSON RD

BURFORD PL

ALFRED RD

HERBERT ST

CORKHILL ST

STAPLES ST

ALFRED RD

PASSMORE AV

FAY ST

BURFORD PL

PHYLLIS ST

WHITE ST

HEVRON ST

EUCLA CT

HIGHAM RD

STAPLES ST

LETITIA RD

TURTON ST

DIRECTION

WAY

___________ LEGEND ___________




Figure 4.2aBAL Contour (Method 2) Map


0 25 50 75 100 125 150 175 200

Metres

_________ SCALE (A3) _________


SOUTHNEDLANDS

BICTON

CORBETT

NORTHFREMANTLE


MOSMAN PARK

COTTESLOE

FREMANTLE

__________ LOCALITY __________




Rocky Bay Reserve &

Cypress Hill

THOMPSONRD

HARVEST RD

AINSLIE RD

JOHN ST

RULE ST

THOMPSON RD

BURFORD PL

ALFRED RD

HERBERT ST

CORKHILL ST

STAPLES ST

ALFRED RD

PASSMORE AV

FAY ST

BURFORD PL

PHYLLIS ST

WHITE ST

HEVRON ST

EUCLA CT

HIGHAM RD

STAPLES ST

LETITIA RD

TURTON ST

DIRECTION

WAY

___________ LEGEND ___________




Figure 4.2bBAL Contour (Method 2) Map


0 25 50 75 100 125 150 175 200

Metres

_________ SCALE (A3) _________


SOUTHNEDLANDS

BICTON

CORBETT

NORTHFREMANTLE


MOSMAN PARK

COTTESLOE

FREMANTLE

__________ LOCALITY __________




Rocky Bay Reserve &

Cypress Hill

Post Mitigation



5 Bushfire Risk Management Recommendations

Bushfire risk within the City of Fremantle has been identified by the DFES Bushfire Prone Area map and

quantified in Section 4 of this plan with the classification of the vegetation and calculation of BAL

ratings based on BAL Method 2 from AS3959-2009 presented as BAL contour maps.

Mitigation strategies for bushfire risk can be broken into several management areas as indicated by

the DFES Guidelines for Planning a Bushfire Risk Management Plan. These are listed below:

• Fuel management - Treatment reduces or modifies the bushfire fuel through manual, chemical

and prescribed burning methods;

• Ignition management - Treatment aims to reduce potential human and infrastructure sources

of ignition in the landscape;

• Preparedness - Treatments aim to improve access and water supply arrangements to assist

firefighting operations;

• Planning - Treatments focus on developing plans to improve the ability of firefighters and the

community to respond to bushfire; and

• Community Engagement - Treatments seek to build relationships, raise awareness and change

the behaviour of people exposed to bushfire risk.

For this report, mainly fuel management and community engagement strategies are recommended to

be implemented by the responsible agencies to reduce or mitigate against bushfire risk.

The BAL contour maps indicate that a number of existing houses are subject to a BAL rating above BAL-

29. The vegetation impacting on these houses is a priority to consider with respect to reducing the BAL

exposure to the subject houses.

The following section details the recommendations to manage the bushfire risk on all houses that may

potentially be impacted by bushfire but primarily those that are subject to BAL’s greater than BAL-29.

As the houses in the subject area are existing it is important to mitigate the risk as far as practically

possible without compromising the aesthetics, environmental and cultural values of the area. There

are a small number of vacant Lots situated in the vicinity that are potentially exposed to a BAL of BAL-

12.5 or greater. Future houses on these Lots will be required to be constructed to the standard

appropriate to the BAL for the site. This is to be determined prior to construction and is to be

undertaken as a BAL Method 2 assessment.

The recommendations for bushfire risk management detailed in this Section are to be read in

conjunction with the NFFVM (2016). Furthermore, it is recommended that neighbouring residents of

the North Fremantle foreshore are made aware of bushfire safety precautions throughout the summer

months. This should entail heightened awareness of suspicious activity in the area and information for

property preparedness and actions during a bushfire in the area, to include actions such as closing all

doors and windows to prevent impact from smoke and ember attack. Information regarding property

preparedness and bushfire precautions can be accessed from the DFES website.



Recommendations made throughout this report are to be undertaken on an ongoing basis to maintain

vegetation structures where changes in the vegetation and fuel structure are recommended to provide

continuous management of bushfire risk in perpetuity.

Vegetation Management

Asset Protection Zones

Implementing an Asset Protection Zone (APZ) creates a low fuel area surrounding any current or future

buildings. This will decrease the potential bushfire’s intensity, minimise the likelihood of direct flame

contact and reduce the exposure of the buildings to radiant heat. It will also be important for firefighter

and occupant’s safety during fire suppression activities.

An APZ is an area maintained as either a non-vegetated area or as low threat vegetation managed in a

minimal fuel condition as per AS 3959-2009 s2.2.3.2 (e) and (f). A minimal fuel condition is stated in

the standard as meaning “there is insufficient fuel available to significantly increase the severity of the

bushfire attack” and being “recognisable as short cropped grass for example to a nominal height of

100mm.” Refer to Appendix 4 of this Plan for further detail. The size of an APZ surrounding buildings is

dependent on the BAL, so as to achieve a BAL of no greater than BAL-29 where possible within the lot

boundary. With reference to the site of Rocky Bay Reserve and Cypress Hill, due to a number of

restrictions including the size of the reserves it is unfeasible to install APZ’s to the full extent required

and the intent is rather to reduce BAL’s by modifying vegetation types and undertaking other mitigation

measures to reduce bushfire impact.



Bushfire Risk Management Recommendations by Zone

5.2.1 Management Zone 5: Cypress Hill

Existing EnvironmentManagement Zone 5- Cypress Hill contains Classified Vegetation Area 6 being Class B- Woodland(AS3959-2009). Cypress Hill predominantly comprises native remnant vegetation and revegetation,and along with the remainder of Management Zone 5, being the Rocky Bay Cliff Top, is the mostsignificant area for bushfire risk management considerations due to the size of the reserve and abilityfor significant fire spread that would impact neighbouring residential lots.

Recommendations for ManagementThis area is currently classified as Woodland Vegetation (AS3959:2009), and to reduce the BAL on

properties surrounding this reserve it is recommended the vegetation be modified to meet the criteria

of Class D- Scrub (refer Table 2.3 of AS3959-2009), that is shrub and scrub vegetation to 4m in height.

This will change the extent of the BAL into a number of Lots but is not enough to alter the overall BAL

for any of the lots impacted by a BAL above 12.5 (see Figure 4.2a and 4.2b) for pre and post mitigation

BAL Contours). The occasional tree can remain but should be managed (see Section 5.2.2 for tree

management). Residential landowners are required to maintain APZ’s within their lot boundary which

should include reducing fuel build-up and removal of dead materials (see Appendix 4 for reference).

Acacia rostellifera should be removed and replaced with low to tall shrubs, with ongoing management

undertaken to control regrowth.

A network of paths, gardens and open areas making up a semi- managed landscape and providingdiscontinuous fuel can be created to further reduce bushfire intensity. This recommendation alignswith those detailed in the North Fremantle Foreshore Vegetation Management Plan, City of Fremantle(Ecoscape, 2016). Vegetation modification in this area is unlikely to be enough to be able to excludethe Vegetation Classification in accordance with AS3959-2009 Exclusions 2.2.3.2 (f) as there is likely tobe sufficient fuel in the area to sustain a fire run.

Woodland vegetation (trees) within the Rocky Bay Cliffs and Slopes Management Zone portion of

Cypress Hill including along the edge of Harvest Street, can remain as Woodland. Altering this section

of vegetation from Woodland to Scrub by removing trees in unfeasible due to erosion issues and access

constraints.

Ongoing management of the area of Cypress Hill will be required. This is to ensure the area is

continually managed for bushfire risk and is to include measures such as ongoing weed control,

management of regrowth of Acacia that has been removed, removal of dead vegetation and ongoing

management of firebreaks. Firebreaks are to be maintained along the north west and south west

boundaries of Cypress Hill (abutting residential lots), with reference to the City of Fremantle Fire

Prevention notice.



Species Recommended for RevegetationTable 22 -Management Zone Five revegetation recommendations column for Cypress Hill of the NFFVM(2016) refer to a number of tree species to be replanted in the area. The tree species listed should notbe planted within Classified Vegetation Area 6 of Cypress Hill itself, with the exception of the Cliffs andSlopes areas as these areas will remain as Woodland Vegetation Classification. It is preferable that TallShrubs from the Cypress Hill species list are not planted within 20m of the residential houses.

Photo 9: Acacia requiring removal and management Photo 10: Acacia requiring removal and management

Photo 11: Harvest Road Woodland and slopes Photo 12: Harvest Road

Photo 13: Maintained firebreak (APZ) at Cypress Hill Photo 14: Firebreaks to be managed

Implementation & Maintenance ResponsibilitiesResidential Lot owners are responsible for maintaining APZ’s within their Lot boundary. The WAPC isresponsible for bushfire risk management recommendations listed above, including maintenance of afirebreak where possible. The City of Fremantle should work closely with the WAPC to manage the areaof Cypress Hill as a continuous landscape.

HARVEST RD

CORKHILL ST

AINSLIE RD

PHYLLIS ST

ALFRED RD

DIRECTIONWAY

HIGHAM RD

AREA6

AREA6

AREA5

AREA5

AREA7

AREA6

___________ LEGEND ___________


FirebreakManagement Zones (NFFVM, 2016)

Cypress Hill / Rocky Bay Cliff TopRocky Bay Cliffs and Slopes

Post Modified VegetationClass (D) ScrubClass (C) ShrublandClass (B) Woodland



0 25 50 75 100

Metres

_________ SCALE (A3) _________


SOUTHNEDLANDS

BICTON

CORBETT

NORTHFREMANTLE


MOSMAN PARK

COTTESLOE

FREMANTLE

__________ LOCALITY __________




Rocky Bay Reserve &

Cypress Hill

Figure 5.1Modified Vegetation Areas



5.2.2 Management Zone 5: Rocky Bay Cliff Top (also known as Rocky Bay HeritageTrail)

Existing EnvironmentManagement Zone 5 contains Classified Vegetation Areas 4 (Scrub), 5 (Woodland), 6 and 7 (Woodland)as per AS3959:2009 Vegetation Classification. It contains some heavy fuel loads ranging from 15 to30tn/ha. Management Zone 5 is the most significant area for bushfire risk management and poses thegreatest bushfire risk due to the extent of the vegetation and relatively high fuel loads of the area.

Recommendations for ManagementClassified Vegetation Area 4- currently Classified as Scrub (AS3959-2009) can remain as is, with theexception of general maintenance including the removal of dead vegetation. Any revegetation withinthis area will need to be undertaken to not increase the Vegetation Classification from Scrub toWoodland, therefore no trees should be introduced into the area.

Classified Vegetation Area 5 is currently Classified as Woodland (AS3959-2009). It is recommended thisarea be modified to Shrubland Vegetation Classification. This will change the extent of the BAL into anumber of Lots but is not enough to alter the overall BAL for any of the lots impacted by a BAL above12.5 (see Figure 4.2a and 4.2b) for pre and post mitigation BAL Contours. Acacia rostellifera should beremoved and the area replanted with species described below. Continual management of resproutingacacia will need to be undertaken. The area should be landscaped to encompass limestone paths tocreate separation between vegetation areas, not only between the Woodland of Vegetation Area 7and the Shrubland of the Rocky Bay Heritage Trail but also within the Shrubland (Vegetation Area 5)itself. Furthermore, a firebreak should be installed and maintained between the vegetation and theresidential lots or the managed garden beds at the rear of the residential lots (See Figure 5.1). Thisshould be limestone surface to approximately 2m wide to create adequate access to the rear of thelots as required (with reference to the City of Fremantle Fire Prevention notice).

A number of large trees can remain in this area, but will need to be pruned so that branches are notoverhanging buildings or areas containing other flammable materials or vegetation. Ladder fuels fromaround the base of the trees are to be removed to reduce the likelihood of crowning from these treesduring a bushfire. Dead material should also be removed from the trees. General maintenance of thesetrees should be ongoing. Appendix 4 refers to management of trees within APZ’s and this is deemedappropriate management for trees that are retained in this area.

There are a number of managed gardens adjacent to the residential lots that are currently managed inaccordance of an APZ (see Photo 15). These garden areas should be continued to be maintained inaccordance with APZ criteria (refer Appendix 4).

Recommendations specific for Rule Park itself are detailed in a separate section below, however as thearea of Rule Park is linked to Management Zone 5 this needs to be taken into consideration so that anyfuture revegetation at Rule Park does not increase the bushfire risk linking into Management Zone 5.

Species Recommended for RevegetationSpecies referred to in Table 22, (Management Zone Five revegetation recommendations) column forRocky Bay Trail of the NFFVM (2016) can be planted within this zone with the exception of the TallShrubs as these species are greater than 2m in height and will contribute to a greater BAL than thatmodelled on Shrubland of this area (refer Appendix 1 of NFFVM, 2016).



Photo 15: Managed area forming APZ Photo 16: Paths creating breaks between vegetation

Photo 17: Low fuel- managed areaPhoto 18: Build up of fuel including dead material

adjacent to residential lots

Implementation & Maintenance ResponsibilitiesThe City of Fremantle is responsible for management of this area, including maintenance of thefirebreak at the back of the residential lots where feasible. Residential landowner responsibilities areto maintain appropriate APZ’s within residential lot boundaries, as per Appendix 4.



5.2.3 Management Zone 6: Rule Park

Existing EnvironmentThis area comprises parkland that is currently primarily managed in a low threat state (Photo 19).Vegetation Areas 4 (Scrub) and 5 (Woodland) border Rule Park which itself is Low threat vegetation(managed lawns).

Recommendations for ManagementIt is recommended that the resprouting Acacia (as shown in Photo 20 below) be removed, as once thisvegetation has grown to its full potential it may result in an increased BAL to the houses located alongRule Street and the rear of Phyllis Street. If Rule park is planned for revegetation as discussed in theNFFVM (2016), it is recommended that shrub species be selected and a buffer with a minimum of 22mto the houses on Rule Street and the rear of Phyllis Street be applied so that the BAL is not increasedgreater than that of the current BAL - 12.5 rating for these houses. Alternatively, it is recommendedthat the area be planted out and maintained in accordance with AS3959:2009 Exclusions s2.2.3.2 (f)apply (refer Appendix 3).

Species Recommended for RevegetationSpecies referred to in Table 22, (Management Zone Five revegetation recommendations) column forRule Park of the NFFVM (2016) are recommended as suitable species from a bushfire risk managementperspective, with the exception of the tree species (Eucalyptus and Melaleuca). Planting tree speciesin this zone has potential to increase the BAL rating on properties surrounding Rule Park, thereforeshrub species <2m in height are more appropriate to be planted in this area.

Photo 19: Managed areas of Rule Park Photo 20: Resprouting Acacia to be removed

Implementation & Maintenance ResponsibilitiesThe City of Fremantle is responsible for management of this area.



5.2.4 Management Zone 6: Rocky Bay Principal Shared Path

Existing EnvironmentThis area contains identified vegetation Areas 1 (Woodland), 2 (Scrub) and 3 (Shrubland), perAS3959:2009 Vegetation Classification. The area is primarily used for recreation, running parallel to theshared path and is generally readily accessible, with the exception of some areas located on the otherside of the fence line where the slopes begin to increase to the cliff face.

Recommendations for ManagementRemoval of dead vegetation, pruning and managing vegetation in close proximity of houses are theprimary bushfire risk management requirements for this area (Photo 21) this will assist in improvingthe aesthetics of the area.

Vegetation overhanging the shared path should be trimmed along with the vegetation between thepath and the fence line where vegetation is overhanging the fence line (See Photo 21). Additionally,the vegetated areas between the fence line and the shared path should be reduced and managed to astate that is in accordance with AS3959:2009 exclusions 2.2.3.2 (f) (refer Appendix 3). The managementof the vegetation along the path should be treated as a managed garden to be reticulated, there iscurrently some reticulation in the area and could be reinstated to assist in the management of thearea, the use of mulch and low shrubs is recommended.

The removal of Victorian Teatree will significantly reduce the fire risk in this area. Where VictorianTeatree is removed, revegetation should be undertaken so at to not increase the Vegetation Type fromthe existing classified Vegetation Types (Figure 4.1a) which would subsequently increase the BAL’s ontoadjacent houses. Species that may result in a lower BAL, for example replanting with shrub species,rather than those considered to be scrub or woodland, is recommended.

Species Recommended for RevegetationAll species referred to in Table 23 (Management Zone 6 revegetation recommendations) of the NFFVM(2016) are recommended as suitable species to be planted in this zone from a bushfire riskmanagement perspective. In areas between the fence line and the waterline, replanting with selectedspecies from this list will not increase the BAL. In areas between the fence line and the shared pathreplanting should only be undertaken where it can be managed in a state in accordance withAS3959:2009 exclusions 2.2.3.2 (f) (refer Appendix 3) and example shown in Photos 23 and 24 below.

Implementation & Maintenance ResponsibilitiesThe City of Fremantle is responsible for management of this area. Residential lot owners areresponsible for maintaining APZ’s within their lot boundary.



Photo 21: Dead vegetation contributing toincreased fire risk

Photo 22: Vegetation overhanging fence line

Photo 23: Example of managed garden Photo 24: Managed garden – low threat

Photo 25: Proximity of vegetation to existing houses



5.2.5 Management Zone 7: Rocky Bay Cliffs and Slopes

Existing EnvironmentThe vegetation contained within this management zone is primarily on the cliff face associated withsteep slopes and inaccessible areas. It contains Vegetation Areas 1, 2, 3, 6 and 7, classed as beingWoodland, Scrub and Shrubland Vegetation Classification (AS3959-2009) (Figure 4.1). Significantmanagement of the vegetation to reduce bushfire risk is unfeasible due to inability to access much ofthe area. Erosion through vegetation removal is also of concern in this area, therefore removal ofvegetation will need to be undertaken with due consideration and replanting undertaken to maintainsoil stability.

Recommendations for ManagementWhere it is safe to do so, species such as Victorian Teatree and False Bamboo should be removed andreplaced with species that will not increase the BAL’s onto adjacent houses. Specifically, vegetationArea 3 should be replaced with Shrub species no greater than 2 metres in height. Species can includeground covers and low shrubs. Dead material should also be removed if access permits.

Species Recommended for RevegetationSpecies referred to in Table 24 (Management Zone Seven revegetation recommendations) of theNFFVM (2016) are recommended as suitable species to be planted in this zone from a bushfire riskmanagement perspective. Tree species from the selection for both Rocky Bay Cliffs and Rocky BaySlopes should only be planted within Classified Vegetation Areas 1, 6 and 7 (Figure 4.1a and 4.1b).Planting tree species in Vegetation Areas 2 and 3 will increase the bushfire risk of these areas and willpotentially increase the BAL ratings for adjacent houses.

Photo 26: Cliffs and Slopes Photo 27: Dead material requiring removal

Implementation & Maintenance ResponsibilitiesThe City of Fremantle is responsible for management of this area.



5.2.6 Management Zone 7: Waugyl Cave

Existing EnvironmentWaugyl Cave is mostly clear from surface vegetation within the cave entrance and the cave itself. It islocated within the Rocky Bay Cliffs and Slopes Management Zone 7 and is situated on the side of thecliff face accessed by stairs and a short path leading to the cave. Due to the proximity of the cave tothe bottom of the cliff and the water’s edge there is no significant bushfire risk to the cave itself.

Recommendations for ManagementThe area surrounding the entrance to the cave should be maintained to keep dead and overgrownvegetation away from the caves entrance. The cave is frequented by squatters and the North FremantleForeshore Management Plan (2013) details a number of fires that were lit within the cave (2001-2012FESA Fire Callout Records). With respect to this and its frequent use by the public, consideration mustbe given to the risk associated of an illegally lit fire escaping, resulting in a broader fire in the area. It istherefore recommended, that due to the potential increased bushfire risk and subsequent damage tothe cave itself through the instability of the limestone exposed to radiant heat from a bushfireperspective, that revegetation at the caves entrance is avoided.

If revegetation is however undertaken to achieve alternative outcomes, consideration should be givento replanting species that will retain the current BAL rating rather than increasing it. This would includeplanting shrub and scrub species rather than woodland (tree species).

Photo 28: Access to Waugyl Cave Photo 29: Entrance to Waugyl Cave

Implementation & Maintenance ResponsibilitiesThe City of Fremantle is responsible for management of this area and collaboration with TraditionalOwners.



5.2.7 Vegetation Area 8- recommendations

Classified Vegetation Area 8 (Figure 4.1) does not form part of a Management Zone and does not havean associated BAL determined for the area however it is recommended that some level of managementbe undertaken of this area to reduce bushfire risk posed by this vegetation on adjacent properties.

Bushfire management measures should incorporate removal of dead vegetation, trimming ofvegetation overhanging neighbouring properties and overhanging the footpath. The area should bemodified to create the area into a maintained garden state to reduce bushfire attack and to reducelikeliness of a bushfire from the Rocky Bay Principal Shared Path travelling through this area.

Photo 30: Overhang pruning required Photo 31: Dead material requiring removal

Implementation & Maintenance ResponsibilitiesCity of Fremantle and residential lot owners for maintenance of APZ’s within lot boundaries.



6 References

• AS3959-2009 Construction of buildings in bushfire-prone areas (Standards Australia, 2009).

• Corporate Policy Statement No.42: Planning for land use, development and permitting affecting

the Swan Canning Development Control Area (Department of Parks and Wildlife and Swan River

Trust, 2016).

• City of Fremantle Fire Prevention (Firebreak Notice) http://www.fremantle.wa.gov.au/

residents/ community-safety/fire-prevention

• North Fremantle Foreshore Vegetation Management Plan, Ecoscape (2016) .

• North Fremantle Foreshore Management Plan, UDLA (2013).

• Overall Fuel Hazard Assessment Guide, 4th Edition July 2010 (Department of Sustainability and

Environment, Victoria).

• The State Planning Policy No. 3.7: Planning in Bushfire Prone Areas (SPP 3.7) (Western

Australian Planning Commission and Department of Planning, 2015).

• Visual Guide for Bushfire Risk Assessment in WA (Western Australian Planning Commission,

February 2016).

• BAL Contour Maps- Factsheet Version 2 January 2016 (western Australian Planning Commission

2016).

• Estimating the length to breadth ratio of elliptical forest fire patterns, M.E. Alexander (1985)



7 Appendices

Appendix 1

Methods 2 BAL Calculations and AssumptionsThe BAL Method 2 calculations and assumptions that have been utilised in the bushfire risk

management plan for the North Fremantle Foreshore area are summarised in the tables following for

each vegetation area. Overall the default AS3959-2009 fuel loads have been retained for the

calculations with the mitigation works proposed to change vegetation types by modifying the fuel

structure of the vegetation area.

The effective slope that has been applied to the specific vegetation areas is the ground slope under the

classified vegetation and is determined for each area of classified vegetation. The slope was measured

or assessed that will significantly influence fire behaviour and the potential impact on the assets with

reference to actual potential fire runs.

Flame width is assumed to be 100 m in vegetation areas were a fire can run >100m, in areas where the

vegetation is restricted to narrow strips such as those along the river have had the head fire/flame

width modified. The modification has utilised the short run calculator based on the methods from

Alexander (1985) as approved by DFES.

The schematic images below show the areas of Rocky Bay and Cypress Hill with estimated flame width

calculations and transects where cross slopes and flank fires were utilised.

Schematic of Rocky Bay area



Schematic of Cypress Hill area

Vegetation Area 1

Derivation of Vegetation Separation Distances for the Mapped BAL Contours

BAL Determination

MethodMethod 2 as per AS 3959-2009 Appendix B.

Refer to Appendix 2 this Plan

Calculation Variables

Input Values Applied

AS 3959 Default Value(Table 2.4.1 & Appendix

B)

Assessed / ModifiedValue

Fire Danger Index 80

Vegetation Classification Class B Woodland

Vegetation Fuel Load - Surface -

Vegetation Fuel Load - Overall -

Vegetation Height -

Effective Slope 0 degrees

Site Slope 30

Flame Width 20m

Elevation of Receiver -

Separation Distances Represented by the Mapped BAL Contours

Calculated Separation Distances(metres) - Method 2 (AS3959-2009 Appendix B)

BAL Rating

BAL-FZ BAL-40 BAL-29 BAL-19 BAL12.5

<9.59.5-

<11.911.9-<15.3

15.3-<19.2

19.2-<100



Vegetation Area 2


BAL Determination MethodMethod 2 as per AS 3959-2009 Appendix B.




AS 3959 Default Value(Table 2.4.1 & Appendix B)

Assessed / Modified Value


Vegetation Classification Class D Scrub



Vegetation Height -

Effective Slope 0o

Site Slope 30

Flame Width 20m



Calculated Separation Distances(metres) - Method 2 (AS3959-2009Appendix B)

BAL Rating


<9 9-<11.3 11.3-<14.6 14.6-<18.518.5-<100



Vegetation Area 3


BAL Determination






Assessed / ModifiedValue


Vegetation Classification Class C Shrubland



Vegetation Height -

Effective Slope 0o

Site Slope 00

Flame Width 2.2m



Calculated Separation Distances(metres) - Method 2 (AS3959-2009 Appendix B)

BAL Rating


<4.8 4.8-<5.3 5.3-<6 6-<6.86.8-<100



Vegetation Area 4


BAL Determination











Vegetation Height -

Effective Slope 0o

Site Slope 00

Flame Width 7.32m




BAL Rating


<8.1 8.1-<9.3 9.3-<11.111.1-<13.2

13.2-<100



Vegetation Area 5- Pre-Mitigation works












Vegetation Height -

Effective Slope 6o

Site Slope 00

Flame Width 7.32m




BAL Rating


<11.211.2-<12.5

12.5-<14.514.5-<16.9

16.9-<100



Vegetation Area 5- Post-Mitigation works









Vegetation Classification Class C Shrubland



Vegetation Height -

Effective Slope 6o

Site Slope 00

Flame Width 7.32m




BAL Rating


<6.8 6.8-<7.9 7.9-<9.5 9.5-<11.511.5-<100



Vegetation Area 6- Pre-Mitigation works












Vegetation Height -

Effective Slope 15o

Site Slope 00

Flame Width -




BAL Rating


<23.523.5-<30.6

30.6-<41.941.9-<55.5

55.5-<100



Vegetation Area 6- Pre-Mitigation works, Harvest St area












Vegetation Height -

Effective Slope -15o

Site Slope 00

Flame Width -




BAL Rating


<5.4 5.4-<7.3 7.3-<10.910.9-<16.1

16.1-<100



Vegetation Area 6- Post-Mitigation works












Vegetation Height -

Effective Slope 15o

Site Slope 00

Flame Width -




BAL Rating


<15.415.4-<20.5

20.5-<29.229.2-<40.2

40.2-<100



Vegetation Area 6- Post-Mitigation works, Harvest St area












Vegetation Height -

Effective Slope -15o

Site Slope 00

Flame Width -




BAL Rating


<6.1 6.1-<8.3 8.3-<12.412.4-<18.2

18.4-<100



Vegetation Area 7












Vegetation Height -

Effective Slope 16o

Site Slope 00

Flame Width 21.96




BAL Rating


<21.721.7-<25.1

25.1-<30 30-<35.835.8-<100



Appendix 2Bushfire Attack Level Assessment Methodology

The Australian Standard AS 3959-2009 Construction of Buildings in Bushfire Prone Areas defines a

Bushfire Attack Level (BAL) as:

“A means of measuring the severity of a building’s potential exposure to ember attack, radiant heat

and direct flame contact, using increments of radiant heat expressed in kilowatts per metre squared,

and is the basis for establishing the requirements for construction to improve protection of building

elements from attack by bushfire.”

AS 3959-2009 defines six categories of Bushfire Attack Level (BAL) (AS 3959 Appendix G); provides the

assessment methodology (AS 3959 s2 and Appendix B); and specifies constructions standards

corresponding to each BAL (AS 3959 s3 Table 3.1). The BAL’s and corresponding descriptions of the

predicted levels of exposure and heat flux exposure thresholds are contained in the table on the

following page.

AS 3959-2009 provides two methods to calculate Bushfire Attack Levels:

1. Method 1 - a simplified procedure that involves five procedural steps to determine the BAL.

It is subject to some limitations of the circumstances in which it can be used.

2. Method 2 - a detailed procedure using calculations to determine BALs where a more specific

result is sought or site conditions are outside the scope of Method 1. In particular, the use of

Method 2 is to apply if the effective slope under the classified vegetation is greater than 200

down slope (and no more than 300 down slope) and the slope of the land between the site

and the classified vegetation is no more than 200 regardless of slope type.

Method 1 – Summarised Procedure

• Determination of the area to be assessed

• Determine predominant vegetation type(s) within 100 metres of the site and classify

• Determination of distance of the site, building or building envelop from the classified

vegetation type(s)

• Determination of the effective slope under the classified vegetation type(s)

• Determination of BAL’s - Forest Fire Danger Index (FFDI) of 80 is used for WA

Separation Distance: The distance from a subject site (or building) to a specific area of classified

vegetation (i.e. the bushfire threat) is labelled in the tables of this Plan as a separation distance. This

distance is measured to a point in the vegetation area represented by the “edge of the vegetation” as

per AS 3959 -2009 s2.2.4 and the “base of the bushfire prone vegetation (not the canopy)” as per the

BAL Assessment [Basic] Factsheet Version 1 December 2015 WAPC. The exact point of measurement is

then decided by the assessor on the basis of the fuel structure and expected fire behaviour. If a

precautionary approach is considered appropriate to a given situation the measurement will be taken

at the canopy line.



Bushfire Attack Level Definitions and Corresponding Sections Specifying Construction Requirements (Source:AS 3959-2009, Appendix G and Table 3.1)

BushfireAttackLevel(BAL)

Description of Predicted Bushfire Attack and Levels of Heat Flux ExposureConstruction

Section ofAS 3959

BAL - LOWThere is insufficient risk to warrant specific construction requirements but there

is still some risk.4

BAL - 12.5

There is risk of ember attack.

The construction elements are expected to be exposed to a heat flux not greaterthan 12.5 kW/m2

3 and 5

BAL - 19

There is a risk of ember attack and burning debris ignited by wind borne embersand a likelihood of exposure to radiant heat.

The construction elements are expected to be exposed to a heat flux not greaterthan 19 kW/m2

3 and 6

BAL - 29

There is an increased risk of ember attack and burning debris ignited by windborne embers and a likelihood of exposure to an increased level of radiant heat.


3 and 7

BAL - 40

There is a much increased risk of ember attack and burning debris ignited bywind borne embers, a likelihood of exposure to a high level of radiant heat and

some likelihood of direct exposure to flames from the fire front.


3 and 8

BAL - FZ

There is an extremely high risk of ember attack and burning debris ignited by windborne embers, a likelihood of exposure to an extreme level of radiant heat and

direct exposure to flames from the fire front.

The construction elements are expected to be exposed to a heat flux greater than40 kW/m2

3 and 9



Appendix 3Vegetation Classification Exclusions (AS 3959-2009 s2.2.3.2)

Certain vegetation can be excluded from being classified in which case the Bushfire Attack Level shall

be rated as BAL-LOW and no bushfire specific construction requirements apply. Such vegetation is one

or a combination of the following:

a) Vegetation of any type that is more than 100m from the site.

b) Single areas of vegetation less than 1ha in area and not within 100m of other areas

of vegetation being classified.

c) Multiple areas of vegetation less than 0.25ha in area and not within 20m of the site

or each other.

d) Strips of vegetation less than 20m in width regardless of length and not within 20m

of the site or each other, or other areas of vegetation being classified.

e) Non-vegetated areas, including waterways, roads, footpaths, buildings, and rocky

outcrops.

f) Low threat vegetation, including grassland managed in a minimal fuel condition (i.e.

insufficient fuel available to significantly increase the severity of a bushfire attack –

recognisable as short cropped grass to a nominal height of 100mm for example),

maintained lawns, golf courses, maintained public reserves and parklands, vineyards,

orchards, cultivated gardens, commercial nurseries, nature strips and windbreaks.



Appendix 4Asset Protection Zones (APZ) - Description, Establishment, Maintenance and

Standards

Source: Guidelines for Planning in Bushfire Prone Areas (DoP/DFES v1.1 2017) Appendix 4 Element 2

Description: An APZ is an area surrounding a building that is managed to reduce the bushfire hazard

to an acceptable level (by reducing fuel loads). The width of the required APZ varies with slope and

vegetation. The APZ should at a minimum be of sufficient size to ensure the potential radiant heat

impact of a fire does not exceed 29kW/m² (BAL-29). It should be lot specific.

(For subdivision planning, hazard separation in the form of using subdivision design elements or

excluded and low threat vegetation adjacent to the lot may be used to reduce the dimensions of the

APZ within the lot).

Defendable Space: The APZ includes a defendable space which is an area adjoining the asset within

which firefighting operations can be undertaken to defend the structure. Vegetation within the

defendable space should be kept at an absolute minimum and the area should be free from

combustible items and obstructions. The width of the defendable space is dependent on the space

which is available on the property, but as a minimum should be 3 metres.

Establishment: The APZ should be contained solely within the boundaries of the lot on which the

building is situated, except in instances where the neighbouring lot or lots will be managed in a low-

fuel state on an ongoing basis, in perpetuity. The APZ may include public roads, waterways,

footpaths, buildings, rocky outcrops, golf courses, maintained parkland as well as cultivated gardens

in an urban context, but does not include grassland or vegetation on a neighbouring rural lot,

farmland, wetland reserves and unmanaged public reserves.

Native Vegetation: APZ’s can adversely affect the retention of native vegetation. Where the loss of

vegetation is not acceptable or causes conflict with landscape or environmental objectives, such as

waterway foreshore areas and wetland buffers, reducing lot yield may be necessary to minimise the

removal and modification of remnant vegetation.

Responsibility: It is the responsibility of the landowner/proponent to maintain their APZ in

accordance with Schedule 1 ‘Standards for Asset Protection Zones’. It is likely that this requirement

is also contained in the firebreak notice issued by local government under s33 of the Bushfire Act

1954.

.

Regardless of whether an Asset Protection Zone exists in accordance with the acceptable solutions

and is appropriately maintained, it should be noted that fire fighters are not obliged to protect an

asset if they think the separation distance between the dwelling and vegetation is unsafe.



Standards for Asset Protection Zones

Fences: within the APZ are constructed from non-combustible materials (e.g. iron, brick, limestone,

metal post and wire). It is recommended that solid or slatted non-combustible perimeter fences are

used.

Objects: within 10 metres of a building, combustible objects must not be located close to the

vulnerable parts of the building i.e. windows and doors.

Fine Fuel Load: combustible dead vegetation matter less than 6 mm in thickness reduced to and

maintained at an average of two tonnes per hectare. The visual guide below shows a fuel load that

equates to approximately 2t/ha (source: Shire of Augusta Margaret River’s Firebreak and Fuel

Reduction Hazard Notice).

Trees (> 5 metres in height): trunks at maturity should be a minimum distance of 6 metres from all

elevations of the building, branches at maturity should not touch or overhang the building, lower

branches should be removed to a height of 2 metres above the ground and or surface vegetation,

canopy cover should be less than 15% with tree canopies at maturity well spread to at least 5 metres

apart as to not form a continuous canopy. Diagram below represents tree canopy cover at maturity.

Shrubs (0.5 metres to 5 metres in height): should not be located under trees or within 3 metres of

buildings, should not be planted in clumps greater than 5m2 in area, clumps of shrubs should be

separated from each other and any exposed window or door by at least 10 metres. Shrubs greater than

5 metres in height are to be treated as trees.

Ground covers (<0.5 metres in height): can be planted under trees but must be properly maintained

to remove dead plant material and any parts within 2 metres of a structure, but 3 metres from windows

or doors if greater than 100 mm in height. Ground covers greater than 0.5 metres in height are to be

treated as shrubs.



Grass: should be managed to maintain a height of 100 mm or less.

Note that individual local governments may increase the APZ standard compared to the standard

stated above. These would be additional requirements and will be contained in their annual firebreak

notice issued under s33 of the Bushfires Act 1954 and are to be complied with.

The example diagrams below illustrate how the required dimensions of the APZ will be determined by

the type and location of the vegetation

Additional DFES Guidancea) Store firewood at least 20 metres away from the building.

b) Keep gutters free of leaves and other combustible material.

c) Roof mounted evaporative coolers to be fitted with ember screens.

d) Gas cylinders to vent away from a building and be tethered to prevent falling over.

e) Driveways and access ways must allow for safe passage of a fire appliance to all buildings on

the land.

f) Land owners/occupiers must maintain compliance with the local government’s annual

firebreak notice issued under s33 of the Bush Fires Act 1954.

home | city of fremantle - 170239 rocky bay & cypress hill ......north fremantle city of...

Documents