Download - AS 3959 Bushfire Attack Level (BAL) Compliance Report ...€¦ · BAL rating Recommended setback to achieve lower BAL New BAL rating* 28 14 m BAL-29 6 m front setback BAL-19 29 14

Level 1, 50 Subiaco Square Road, Subiaco, WA 6008 P.O. Box 243, Subiaco, WA 6904 Phone: (08) 9380 3100 Fax: (08) 9380 4606 177 Spencer Street, Bunbury, WA 6230 P.O. Box 287, Bunbury, WA 6231 Phone: (08) 9792 4797 Fax: (08) 9792 4708

Email: [email protected] Web: www.strategen.com.au ABN: 32 056 190 419

To: Daniel Calderwood Date: 13 July 2018

Company: Cedar Woods Properties Limited Project No: CED18260.01

Email: [email protected] Inquiries: Zac Cockerill

AS 3959 Bushfire Attack Level (BAL) Compliance Report Stage 1B Millars Landing, Baldivis

Site Details

Address: Lots 1–36 and 38–42, Stage 1B Millars Landing

Suburb: Baldivis State: Western AustraliaLocal Government Area: City of RockinghamDescription of building works: Class 1a buildings with associated Class 10a buildings

Report details

Report/Job number: CED18260.01 Report reference: CED18260_01 R002 Rev AAssessment date: 10 May 2018 Report date: 13 July 2018 Endorsement/Review Zac Cockerill BPAD Level 2: 37803

Introduction

This Bushfire Attack Level (BAL) compliance report has been prepared for 41 residential lots within Stage 1B Millars Landing (hereon referred to as the project area), located in Baldivis, City of Rockingham.

This report provides a post-subdivisional works update of the BAL ratings for individual lots within the project area and has been prepared for the benefit of the developer, future lot purchasers and decision-makers. BAL certificates for each individual lot have been prepared based on the final site compliance check and are appended to this report for use at the building permit stage.

The BAL assessment outlined in this report is the most up to date assessment relating to the project area and therefore supersedes any previous BAL assessments undertaken within the project area, including previous BAL contour mapping contained in Bushfire Management Plans (BMPs) prepared by RUIC Fire (2017) to accompany both the Structure Planning and Stage 1B subdivision planning applications.

This BAL compliance report also takes into consideration the proposed landscaping, drainage and planting regime detail outlined in the most up to date versions of the relevant landscape concepts for POS Areas 1 and 2 to account for the reintroduction of classified vegetation and associated BAL response.

The approach for preparation of this BAL compliance report is consistent with Section 4.2 and Appendix 3 of Guidelines for Planning in Bushfire Prone Areas.

The BAL compliance assessment has been completed by a Level 2 accredited Bushfire Planning and Design practitioner (Zac Cockerill, BPAD37803) in accordance with Method 1 of AS 3959–2009 Construction of Buildings in Bushfire-prone Areas (AS 3959) and results are consistent with on-ground conditions observed at the time of inspection on 10 May 2018.

Should subdivision design or the classified vegetation extent be further modified prior to building construction, then an updated BAL assessment for the affected lots may need to be undertaken to account for these changes.

AS 3959 Bushfire Attack Level (BAL) Compliance Report

CED18260_01 R002 Rev A

13-Jul-18 2

BAL compliance assessment

Results of the BAL compliance assessment are provided in Figure 1 in the form of a BAL contour map and a summary of assessment inputs are provided in the following subsections.

Fire Danger Index

A blanket rating of FDI 80 is adopted for Western Australian environments, as outlined in AS 3959 and endorsed by Australasian Fire and Emergency Service Authorities Council.

Classified vegetation

The spatial extent of classified vegetation and exclusion plots are depicted in Figure 1, along with site photo points to validate site observations. The photo points depicted in Figure 1 relate to the georeferenced site photographs provided in Appendix 1.

Subdivisional and landscaping works have or will result in the following classified vegetation and exclusions within and adjacent to the project area:

• Class B woodland (Plot 1) occurs to the west, northwest and southwest of the project area comprising mixed open canopy eucalypts or banksias over low shrubs or grass

• Class G grassland (Plot 2) occurs to the southwest of the project area throughout cleared, unmanaged areas

• Class D scrub (Plot 3) occurs to the far southwest of the project area comprising revegetated verge areas of Baldivis Road

• POS 1, situated east and southeast of the project area, is currently excluded from classification under a combination of Clause 2.2.3.2 (b) for the central wetland area (Plot 5) and Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

• following full implementation of POS 1 landscaping works as per Appendix 2, future exclusions for POS 1 will include a combination of Clause 2.2.3.2 (b) for the central wetland area (Plot 5), Clause 2.2.3.2 (c) for the two small drainage basins situated either side of the central wetland area (Plot 6) and Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

• POS 2 situated north of the project area is currently excluded from classification under a combination of Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

• following full implementation of POS 2 landscaping works as per Appendix 2, future classified vegetation for POS 2 will include Class G grassland throughout planted drainage areas (Plot 2) and future exclusions will include a combination of Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

• all proposed residential lots and road reserves are in a cleared, non-vegetated state and are excluded from classification under Clause 2.2.3.2 (e) (Plot 4)

• 100 m wide staging buffers, as documented in the RUIC (2017) BMP, have been implemented where possible within future development areas adjacent to the project area and are excluded from classification under a combination of Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

• adjacent land beyond the 100 m wide staging buffer (particularly to the north), has been classified as Class G grassland (Plot 2) due to the unmanaged status of these areas.

Effective slope

All current and future areas of classified vegetation occur on flat land (i.e. effective slope of 0 degrees) as depicted in Figure 1.


CED18260_01 R002 Rev A

13-Jul-18 3

BAL calculations

The BAL impact to the project area has been assessed in the form of BAL contours, utilising assessment results as outlined above. Results of the BAL contour assessment are outlined in Table 1 and depicted in the BAL contour map (Figure 1).

Table 1: BAL contour assessment Classified vegetation Effective slope BAL contour width (m) BAL rating Comment

Class B woodland Flat/ upslope

<10 BAL–FZ No development is proposed in this area

10–<14 BAL–40 No development is proposed in this area

14–<20 BAL–29 Development may occur in this area

20–<29 BAL–19 Development will occur in this area

29–<100 BAL–12.5 Development will occur in this area

Class G grassland Flat/ upslope

<6 BAL–FZ No development is proposed in this area

6–<8 BAL–40 No development is proposed in this area

8–<12 BAL–29 Development may occur in this area

12–<17 BAL–19 Development will occur in this area

17–<100 BAL–12.5 Development will occur in this area

BAL certificates

BAL certificates are provided in Appendix 3 for all 41 residential lots situated within Stage 1B Millars Landing as per the BAL contour assessment outlined in Figure 1. Where more than one BAL rating applies to a single lot, the highest (worst case) BAL rating has been applied, except for Lots 1 and 25–30, which will achieve a worst-case rating of BAL-29 through 1 m building setbacks off the adjacent road enforced through standard R-code setbacks (this is consistent with approved BMP provisions for the Asset Protection Zone, or APZ).

Should a lower BAL rating be realistically achievable through building setbacks then the landowner can refer to detailed advice for recommended setbacks in Table 2. The lower BAL rating may be achieved if the recommended building setback is reflected on the building plan for that lot and a revised BAL certificate can be issued at that time.

Table 2: Recommended setbacks to achieve a lower BAL rating Lot

number Current separation

distance Current

BAL rating Recommended setback to achieve lower BAL New BAL rating*

2 26 m BAL-19 3 m side setback BAL-12.53 12 m BAL-19 5 m tapered rear setback BAL-12.5

4 8 m BAL-29 4 m tapered rear setback BAL-19

5 11 m BAL-29 1 m tapered rear setback BAL-19

5 11 m BAL-29 6 m tapered rear setback BAL-12.5




9 46 m BAL-12.5 4 m side setback BAL-LOW

12 97 m BAL-12.5 3 m side setback BAL-LOW

25 14 m BAL-29 6 m front setback BAL-19




CED18260_01 R002 Rev A

13-Jul-18 4

Lot number

Current separation distance

Current BAL rating Recommended setback to achieve lower BAL New BAL

rating*



*The new BAL rating in Table 2 can only be confirmed once the building plan for the relevant lot has been prepared to demonstrate compliance with the recommended setback. Once the setback has been confirmed, a new BAL certificate for the lower BAL rating can be prepared and issued to accompany the building permit application.

Conclusion and recommendations

This BAL compliance report has been prepared for 41 residential lots within Stage 1B Millars Landing to provide a final BAL check for individual lots for use at the building permit stage. Assessment results are consistent with current on-ground conditions observed at time of inspection on 10 May 2018 and account for future areas of classified vegetation within POS. From these results, Strategen can confirm that the existing BMPs over the site (RUIC 2017) have been implemented as intended throughout the duration of subdivisional works to achieve the bushfire management outcome as planned for in these documents.

In the absence of any change in development design or post-development classified vegetation extent that has not already been accounted for, Strategen considers that the BAL assessment and BAL certificates outlined in this report are accurate to inform individual lot building permit applications.

Should the extent of classified vegetation change or new vegetation be introduced within 100 m of proposed development that has not already been accounted for, then the BAL should be reassessed at the building permit stage to ensure accuracy with on-ground conditions.

Should it be determined through demonstration on the building plan that compliance with the recommended building setbacks has been achieved and subsequently a lower BAL rating has been achieved (as per Table 2), then the lower BAL rating should apply and be reflected in an updated BAL certificate prepared at that time.

The BAL assessment outlined in this report is the most up to date assessment relating to the project area and therefore supersedes any previous BAL assessments undertaken within the project area.

Ongoing requirements of the RUIC (2017) BMPs and current City of Rockingham annual firebreak notice should continue to be implemented as required, particularly with regards to ongoing fuel management of vacant land, POS, road reserves and APZs.

Figure 1 BAL compliance: Stage 1B Millars Landing

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Path: Q:\Consult\2018\CED\CED18260\01_GIS_documents\ArcMap_documents\CED18260_G002_RevF.mxd

[email protected]

Scale at A4

Source: Aerial image: Nearmap, flown 02/2018. Existing cadastre: Landgate 2017. Subdivision layout: Client 05/2018.

Note that positional errors may occur in some areas

0 50 100m

1:3,500

Coordinate System: GDA 1994 MGA Zone 50

Date: 12/07/2018Author: JCrute

¹

Legend

!(

Photo point and direction

Proposed POS

Project area

Proposed lots

100m wide assessment area

150m wide assessment area

Existing cadastre

Surrounding subdivisions

Vegetation classPlot 1: Class B Woodland, flat/upslope

Plot 2: Class G Grassland, flat/upslope

Plot 3: Class D Scrub, flat/ upslope

Plot 4: Excluded under Clauses2.2.3.2. (e) and (f)

Plot 5: Excluded under Clause2.2.3.2 (b)

Plot 6: Excluded under Clause2.2.3.2 (c)

BAL contoursBAL FZ

BAL 40

BAL 29

BAL 19

BAL 12.5

BAL Low

POS 2POS 2

Appendix 1 Site photographs

Photo 1: Plot 1: Class B Woodland



Photo 8: Plot 2: Class G Grassland

Photo 9: Plot 4: Excluded – Non-vegetated & Low threat (Clauses 2.2.3.2 [e] and [f])



Photo 14: Plot 2: Existing exclusion as non-vegetated and low threat (Clauses 2.2.3.2 [e] and [f]). Proposed

revegetation will result in a Class G grassland classification within POS 2.


Photo 16: Plot 2: Existing exclusion as non-vegetated and low threat (Clauses 2.2.3.2 [e] and [f]). Proposed

revegetation will result in a Class G grassland classification within POS 2.

Photo 19: Plot 4: Excluded – Non-vegetated (Clause 2.2.3.2 [e])

Photo 20: Plot 4 and Plot 6 Excluded Clause 2.2.3.2 (f): low threat managed grassland within POS 1. Future

landscaping will introduce small pockets of drainage vegetation excluded under Clause 2.2.3.2 (c).

Photo 21: Plot 4, Plot 5 and Plot 6 Excluded Clause 2.2.3.2 (f): low threat managed grassland within POS 1. Future

landscaping will introduce small pockets of drainage vegetation excluded under Clause 2.2.3.2 (c). Existing wetland vegetation in background excluded under Clause 2.2.3.2 (b)

Photo 22:

Plot 4: Excluded Clause 2.2.3.2 (f): low threat managed grassland within POS 1. Future landscaping will introduce small pockets of drainage vegetation excluded under Clause 2.2.3.2 (c). Existing wetland vegetation in background excluded under Clause 2.2.3.2 (b)


Appendix 2 POS landscape concept plans

N O R T H B A L D I V I S P O S 1

L A N D S C A P E C O N C E P T P L A N

P R E P A R E D F O R C E D A R W O O D S

5 10 20 30 50m0

FEB 2018REV JC1.101JOB NO. 1308505

1:500 @ A1

L A N D S C A P E A R C H I T E C T SL A N D S C A P E A R C H I T E C T S4 1 4 R O K E B Y R D S U B I A C O W A 6 0 0 8T : ( 0 8 ) 9 3 8 8 9 5 6 6 E : m a i l @ p l a n e . c o m . a uL A N D S P A C E P T Y L T D A C N 0 5 6 5 3 8 6 7 9COPYRIGHT This document i s and sha l l rema in the property o f P lan E

EX

TE

NT

OF

S IT

E

EXTENT OF S ITE

FEATURE SHADE STRUCTURE

FORMAL PARK ENTRY

SHADE SHELTER OVERLOOKING REW WETLANDWITH BOARDWALK.

CONCRETE FOOTPATHS

FEATURE PLAYGROUND WITH INDICATIVE LAYOUT PROVIDED

SHADE STRUCTURE & BARBECUE

MANAGED LANDSCAPE PLANTING OF LOW SHRUBS AND GROUNDCOVERS



MANAGED LANDSCAPE PLANTING OF LOW SHRUBS

AND GROUNDCOVERS

TIMBER BOARDWALK TO PATH CROSSINGS

WETLAND BUFFER PLANTING. REEDS AND SEDGES

1.5M GRAVEL MAINTENANCE STRIP

MANAGED LOW WETLAND GROUNDCOVER PLANTING @ 100MM HIGH WITH GRAVEL MULCH

RESOURCE ENHANCEMENT WETLAND

EXISTING VEGETATION TO BE RETAINED & PROTECTED

1 : 5 YR DRAINAGE

REW = 8720m 2

REW + PLANTED BUFFER = 99975m2

1 : 1 YR BASIN560m 2

1 : 1 YR BASIN860m 2

TURFKICKABOUT

AREA

REW

RESOURCE ENHANCEMENT WETLAND PLANTED WITH

NATIVE REEDS AND SEDGES

FUTURE 1:1 YEAR BASIN, PLANTED WITH APPROPRIATE NATIVE REEDS AND SEDGES

DRAINAGE OVERFLOW TO REW.

TURF

TURF

TURF

26m

27.5m

TURF

+5.60

+5.60

+RL5.10

+RL5.10

TURF

TURF

TURFTURF

DRAINAGE OVERFLOW TO REW.

1:1 YEAR BASIN, PLANTED WITH APPROPRIATE NATIVE REEDS AND SEDGES

BOARDWALK THROUGH EXISTING VEGETATION.

BOARDWALK THROUGH EXISTING VEGETATION.

A

B

A

B

+5.60

+5.60

EXTENT OF S ITE

TURF

TURF

TURF

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2.5 5 10 15 25m0

NOV 2017REV KC1.101JOB NO. 1308506

1:250 @ A1

N O R T H B A L D I V I S P O S 2

L A N D S C A P E C O N C E P T P L A N

P R E P A R E D F O R C E D A R W O O D S

L A N D S C A P E A R C H I T E C T SL A N D S C A P E A R C H I T E C T S4 1 4 R O K E B Y R D S U B I A C O W A 6 0 0 8T : ( 0 8 ) 9 3 8 8 9 5 6 6 E : m a i l @ p l a n e . c o m . a uL A N D S P A C E P T Y L T D A C N 0 5 6 5 3 8 6 7 9

COPYRIGHT This document i s and sha l l rema in the property o f P lan E

SHADE STRUCTURE

BOARDWALK

13M MIN OFFSET

CONCRETE FOOTPATHS

FULLY IRRIGATED GARDEN BED

TURF

TURF

TURF TURF MAX 1:6

TURF MAX 1:6

1:1 YEAR BASIN, PLANTED WITH APPROPRIATE NATIVE

REEDS AND SEDGES1:1 TOP WATER LEVEL 5.75

1:1 BASE LEVEL 5.40

AGGREGATE MULCH WITH SPARSE PLANTING TO BASE OF CONVEYANCE SWALE WHERE LOCATED WITHIN FIRE SEPARATION ZONE

Conveyance Swale5 Year ARI (20% AEP)Volume detained (m3) 38Maximum depth (m) 0.21TWL (m AHD) 5.21Inundated Area (m2) 396

100 Year ARI (1% AEP)Volume detained (m3) 274Maximum depth (m) 0.56TWL (m AHD) 5.56Inundated Area (m2) 947

Bio Retent ion bas in1 Year ARIVolume detained (m3) 103Maximum depth (m) 0.35TWL (m AHD) 5.75Inundated Area (m2) 295

STONE PITCHED 1:1 BASIN OVERFLOW

LEVEL 5.75

BC

BC

EXTENT OF WORKS/SITE

EXTENT OF WORKS/SITE

13M MIN OFFSET

EXTE

NT

OF

WO

RK

S/SI

TE

+ 5 .00

EXISTING TREES POTENTIALLY SUITABLE FOR RETENTION PENDING ASSESSMENT

BY A QUALIFIED ARBORIST

FUTURE FOOTPATH CONNECTIONS

EXISTING TREES POTENTIALLY SUITABLE FOR RETENTION PENDING ASSESSMENT BY A QUALIFIED ARBORIST

RL 5.33

RL 5.35

RL 5.15

RL 5.19RL 5.05

RL 5.06

RL 5.28RL 5.30

RL 5.35

RL 5.49

RL 5.67

+ 5.15

+ 5.65

+ 5.65

+ TW 5.60+ BW 5.10

+ TW 5.95

Download - AS 3959 Bushfire Attack Level (BAL) Compliance Report ...€¦ · BAL rating Recommended setback to achieve lower BAL New BAL rating* 28 14 m BAL-29 6 m front setback BAL-19 29 14

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