Original source · versioned page text
210055 - 327 Kinmond Creek Road, COOTHARABA - Bushfire Risk Assessment
Bushfire Attack Level Assessment 327 Kinmond Creek Road, Cootharaba Prepared for Sarah Pearson Prepared by: M: 0423 081 428 E: [email protected] W: www.greentapesolutions.com.au Client Manager: Kelly Matthews Report Number: PR20257_327 Kinmond Creek Rd, Cootharaba_VerA Green Tape Solutions / ABN 20 162 130 627 PO BOX 222, Moggill, QLD, 4070 / PO BOX 282, Morayfield, QLD, 4506 / www.greentapesolutions.com.au Telephone: 07 5428 6372 / Email: [email protected]
See the original
The page text is free to read. Viewing or downloading an original file needs an account.
Log in to see the originalLog in to download the original file
Large file: the download may take up to a minute.
Searchable page text hides email addresses. Original files are unchanged and may show email addresses.
Full text of the other 15 pages
Page 2
DISCLAIMER
Apart from fair dealing for the purposes of private study, research, criticism, or review as permitted under
the Copyright Act, no part of this report, its attachments or appendices may be reproduced by any process
without the written consent of Green Tape Solutions.
Green Tape Solutions has prepared this report for the sole purposes of the Client. This report is strictly
limited to the purpose and the facts and matters stated in it and does not apply directly or indirectly and will
not be used for any other application, purpose, use or matter. The reproduction, adaptation, use or
communication of the information contained within this report may not be used without the written
permission of Green Tape Solutions.
In preparing this report we have assumed that all information and documents provided to us by the Client,
or as a result of a specific request or enquiry, were complete, accurate and up-to-date. Where we have
obtained information from a government register or database, we have assumed that the information is
accurate. Where an assumption has been made, we have not made any independent investigations with
respect to the matters the subject of that assumption. We are not aware of any reason why any of the
assumptions are incorrect.
In this note, a reference to loss and damage includes past and prospective economic loss, loss of profits,
damage to property, injury to any person (including death) costs and expenses incurred in taking measures
to prevent, mitigate or rectify any harm, loss of opportunity, legal costs, compensation, interest and any
other direct, indirect, consequential or financial or other loss.
Document Records - Quality
TITLE Bushfire Attack Level Assessment for 237 Kinmond Creek Road, Cootharaba
FILED AS PR20257_BAL_327 Kinmond Creek Rd, Cootharaba_VerA
Prepared by Reviewed by Approved by
Revision Date
(name/title) (name/ title) (name/title)
Kelly Matthews, Kelly Matthews,
Carla Perkins,
Version A 5/08/2020 Director/Principal Director/Principal
Senior Ecologist
Ecologist Ecologist
PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 2
Page 3
Table of Content 1. INTRODUCTION ....................................................................................................................... 4 1.1 PROPOSED DEVELOPMENT ........................................................................................................... 4 1.2 SITE DESCRIPTION.......................................................................................................................... 4 2. BUSHFIRE REGULATORY FRAMEWORK ......................................................................... 5 3. BUSHFIRE ATTACK LEVEL ASSESSMENT ........................................................................ 6 3.1 STEP 1 – DETERMINATION OF THE RELEVANT FIRE DANGER INDEX (FDI)........................ 7 3.2 STEP 2 - ASSESSMENT OF VEGETATION COMMUNITIES .......................................................... 7 3.3 STEP 3 - ASSESSMENT OF THE EFFECTIVE SLOPE..................................................................... 8 3.4 STEP 4 - ASSESSMENT OF DISTANCE TO THE VEGETATION ..................................................... 8 3.5 STEP 5 - DETERMINATION OF BUSHFIRE ATTACK LEVEL (BAL) .......................................... 8 4. CONCLUSION ...........................................................................................................................11 5. REFERENCES ...........................................................................................................................12 APPENDIX 1 – PROPOSED DEVELOPMENT CONCEPT PLAN ......................................................................... 13 APPENDIX 2 – FLAMESOL RESULTS.................................................................................................................. 14 FIGURES Figure 1: Site Location (Source: Queensland Globe). ........................................................................... 4 Figure 2: Bushfire Attack Level Map......................................................................................................... 10 PLATES Plate 1: Site vegetation. .................................................................................................................................... 8 Plate 2: Existing access track to development site. .............................................................................. 8 PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 3
Page 4
1. Introduction
1.1 Proposed Development
This Bushfire Attack Level (BAL) assessment has been prepared for Sarah Pearson for a
proposed development located at 327 Kinmond Creek Road, Cootharaba (Lot 1 RP 184574)
hereafter referred as the ‘site’.
The proposed development is for a new dwelling house (Class 1a structure) and associated
outbuildings, including a detached garage and carport (Class 10a structures). An existing cleared
vehicle track provides access to the proposed development site from Richards Road, however
access shall be upgraded as part of the proposed development. The proposed development
concept plan is provided in Appendix 1.
1.2 Site Description
The site comprises a single lot with an area of approximately 33,180 m2 (3.32 ha) zoned as Rural
under the Noosa Plan 2020 (Figure 1). The lot is currently vacant and does not support any
existing infrastructure.
The site is fully vegetated and supports remnant native vegetation. Site vegetation forms part of
a larger patch of remnant vegetation that extends to the south-east and east of the site. The site
and surrounding terrain is characterised as gently undulating to low rolling hills.
Figure 1: Site Location (Source: Queensland Globe).
PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 4
Page 5
2. Bushfire Regulatory Framework
Given that bushfire hazard can cause harm to people and social wellbeing, damage to property
and impacts to the economy and environment, the management of bushfire hazard in
Queensland is considered to be an integral component of land use planning and development
decisions.
There are three regulatory mechanisms/instruments relevant to this site that regulate
development to avoid and mitigate potential impacts associated with bushfire hazard:
• State Planning Policy (SPP) – July 2017 (DILGP, July 2017);
• Noosa Council planning scheme – Noosa Plan 2020 (Noosa Council, 2020); and
• Australian Standard AS3959:2018 – Construction of Buildings in Bushfire-prone Areas
(Standards Australia, 2018).
The SPP 2017 identifies the Queensland Government’s policies about matters of state interest
in land use planning and development. The SPP is a broad and comprehensive statutory
planning instrument. It sits above regional plans, standard planning scheme provisions and local
government planning schemes within the hierarchy of planning instruments outlined in the
Planning Act 2016. The SPP is supported by the SPP State Interest guidance material – Natural
hazards, risk and resilience – Bushfire (DSDMIP, 2019) (‘SPP guidance material’) and the
‘Bushfire Resilient Communities – Technical Reference Guide for the State Planning Policy State
Interest - Natural Hazards, Risk and Resilience – Bushfire’ (Queensland Fire and Emergency
Services (QFES), 2019).
The SPP guidance material is used to assist assessment managers and practitioners in applying
the SPP assessment benchmarks when state interests have not been integrated into the local
planning scheme. The SPP assessment benchmarks outlined in Part E of the SPP and Section
4.0 of the SPP guidance apply to development to the extent that the development is assessable
against a planning scheme and only to the extent that the planning scheme is inconsistent with
the SPP.
Australian Standard AS3959:2018 - Construction of Buildings in Bushfire-Prone Areas
(Standards Australia, 2018) specifies the requirements for the construction of buildings in
bushfire-prone areas in order to improve their resistance to bushfire attack. AS3959:2018 applies
to those areas where a regulated map (e.g. planning scheme overlay map) identifies an area as
a bushfire prone area (or similar), requiring calculation of Bushfire Attack Level (BAL) in
accordance with a methodology outlined in the standard.
AS3959:2018 thus prescribes the particular construction details for buildings depending on the
calculated BAL. The detailed requirements relating to construction methods and materials are
typically dealt with as part of building design and enabled via private certification in accordance
with the Building Code of Australia.
The following section of the report provides an overview of the methodology used to assess
bushfire hazard.
PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 5
Page 6
3. Bushfire Attack Level Assessment
To assess the bushfire hazard for the site and proposed development, the following tasks were
undertaken:
• Assessment of regional ecosystem (RE) mapping for the site and surrounding area
(DNRME, 2020);
• Review of the proposed development layout;
• Review of high-resolution aerial imagery for the site;
• A site-based assessment undertaken on 16th July 2020 to:
o Verify the occurrence, extent, composition and structure of vegetation communities
currently existing within and surrounding the site;
o Measure effective and site slope; and
o Assess adjacent bushland, existing fire breaks / trails and access roads.
• Identify potential bushfire hazards and risks. This includes an assessment of the bushfire
risk and a BAL assessment for the proposed development. The BAL assessment
outlines the AS3959:2018 requirements for the construction of future buildings.
Bushfire attack levels (BALs) are used to quantify the levels of attack (radiant heat
exposures/flux) that built structures may experience during a fire event. The BAL is defined 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 the basis for establishing the requirements for construction to improve protection
of building elements from attack by bushfire’ (Standards Australia, 2018).
AS3959:2018 adopts six BAL categories, which are based on the level of radiant heat flux to
which buildings may be exposed to during a bushfire event. This level of heat flux generally
relates to the type of vegetation, effective slope and how far a building is from hazardous
vegetation. In accordance with Sections 2.1 and 3.2.3 of AS3959:2018, the BAL applies to the
entire building and to any attached or adjacent structures within 6 metres of the building.
BALs are calculated in accordance with either Method 1 or 2 outlined in AS3959:2018. Given
that the proposed development shall require clearing to establish an appropriate separation
distance, Method 2 has been used to calculate the minimum separation distances for each BAL.
The following steps were undertaken to calculate these distances:
• Step 1: Determination of the relevant Fire Danger Index (FDI);
• Step 2: Assessment and classification of vegetation communities, fuel loads and
vegetation height within and surrounding the proposed development;
• Step 3: Assessment of the effective slope beneath classified vegetation and the slope
of the land between the site and classified vegetation;
• Step 5: Assessment of distance to the vegetation; and
• Step 6: Determination of Bushfire Attack Level (BAL).
PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 6
Page 7
AS3959:2018 allows for the use of data sets provided by the relevant authority having jurisdiction for the site i.e. Queensland Fire and Emergency Service (QFES). These datasets are published via the Catalyst Fire Management System portal (Queensland Fire and Emergency Services, 2020) for Fire Danger Index and the Bushfire Resilient Communities technical document (Queensland Fire and Emergency Services (QFES), 2019) for published fuel loads. 3.1 Step 1 – Determination of the relevant Fire Danger Index (FDI) QFES datasets for Fire Danger Index are published via the Catalyst Fire Management System portal (Queensland Fire and Emergency Services, 2020). The relevant FDI value for the site is 47. 3.2 Step 2 - Assessment of Vegetation Communities The different types of vegetation communities determine the rate at which dry fuel accumulates. Some vegetation communities protect fuel from drying out in all but extreme bushfire seasons and can then be susceptible to very destructive bushfires. Alternatively, vegetation communities may expose fuels to drying and therefore be frequently available for burning. Frequent bushfires can result in the development of bushfire-tolerant grassy woodlands or grasslands and these present less destructive bushfire behaviour. The site supports remnant native vegetation which forms part of a larger patch of remnant vegetation that extends to the south-east and east of the site. This vegetation is mapped as Category B (remnant) conforming to the regional ecosystem (RE) 12.11.16 – Eucalyptus cloeziana open forest on metamorphics +/- interbedded volcanics (DNRME, 2020). Site verification of the vegetation community within and surrounding the site confirmed the accuracy of this mapping. The average height of the canopy is 21 – 25 m, with an estimated canopy cover of 70%. The shrub layer is generally absent with some small patches of hickory wattle (Acacia disparrima var. disparrima) and red ash (Alphitonia excelsa) with some native vines. The ground layer is dominated by native species including forest grasstree (Xanthorrhoea johnsonii), blue flax lily (Dianella caerulea) and bracken fern (Pteridium esculentum). The vegetation community on site corresponds to a Vegetation Hazard Class (VHC) of 8.1 – Wet eucalypt tall open forest (Queensland Fire and Emergency Services (QFES), 2019). Published fuel loads for this VHC (Queensland Fire and Emergency Services (QFES), 2019) are 31 t/ha for total surface fuel load and 35 t/ha for total overall fuel load. PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 7
Page 8
Plate 1: Site vegetation. Plate 2: Existing access track to development
site.
3.3 Step 3 - Assessment of the Effective Slope
Studies have shown that fires burn more quickly and with greater intensity up slopes, generally
doubling every 10 degrees of slope. Also, the steeper the slope the more difficult it is to construct
ring roads, firebreaks and provide access for emergency crews. Trees situated downhill from
structures will have their crowns close to the structures. This presents bushfire hazards
particularly for exposed structures such as timber decks.
Effective slope is the slope beneath classified vegetation which most influences the bushfire
attack. The topography of the site is classified as gently undulating with an average effective
slope beneath classified vegetation of 3 degrees to the south of the development site. Average
slope was measured on site and verified using spatial contour data (1 m Lidar-derived data
published by DNRME) and the Maximum Landscape Slope raster dataset published as part of
the Bushfire hazard area – Bushfire Prone Area – Inputs dataset published by QFES.
Vegetation to the south is located downslope of the site.
3.4 Step 4 - Assessment of distance to the vegetation
Given that the proposed development is located within remnant vegetation, clearing shall be
required to provide appropriate separation between the development and adjacent vegetation.
Method 2 of AS3959:2018 has been used to calculate the minimum separation distances for
each BAL. The results of this calculation are provided in Step 5 below.
3.5 Step 5 - Determination of Bushfire Attack Level (BAL)
The Bushfire Attack Levels (BALs) for classified vegetation has been calculated using the
Flamesol Method 2 Minimum Distance calculator published by Fire Protection Association (FPA)
Australia (FPA Australia, 2017). The results from the Flamesol calculator are provided in
Appendix 2 and summarised in Table 1.
Figure 2 also illustrates the BALs for the subject site.
PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 8
Page 9
Table 1: Determination of Bushfire Attack Level (BAL) minimum separation distances.
BAL-FZ
Bushfire attack
BAL-12.5 BAL-19 BAL-29 BAL-40 (Flame
level (BAL) →
Zone)
Minimum
34 - <100m 24 - < 34 m 16 - < 24 m 12 - < 16 m < 12 m
distances required
The assessment benchmarks outlined in the SPP guidance material (DSDMIP, 2019) provide a
radiant heat flux of 29 kW/m2 (BAL-29) as an acceptable outcome for assessable development.
A minimum separation distance of 16 m would achieve BAL-29. Clearing of vegetation shall be
required to achieve the recommended minimum separation distance.
However, we note that the development (MCU for new dwelling house) is not assessable against
the Noosa Plan 2020 Bushfire overlay code (Refer to the Table of Assessment for this code).
Therefore, the dwelling can be built in any BAL as long as the separation buffers between the
dwelling and the vegetation meet the distances outlined in Table 1.
Based on the proposed development concept plan provided, the proposed garage and carport
are located approximately 10.4 m and 36.1 m respectively from the dwelling house. Based on
these distances, only the dwelling house would require construction in accordance with the
construction standard specified for the recommended BAL.
PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 9
Page 10
Figure 2: Bushfire Attack
level Map
Project: PR20257 327 Kinmond Creek
Rd, Cootharaba
Tree Survey
Retain
Remove
Driveway
Proposed development
BAL updated
BAL FZ - 12m
BAL 40 - 16m
BAL 29 - 24m
BAL 19 - 34m
BAL 12.5 - 100m
Notes:
-Flora and Fauna Survey by Green Tape Solutions and NGH
Environmental 2019
-Site Infrastructure and Impact Areas from Client
-Base map Copyright (c) Esri and its data suppliers.
-Regional Ecosystems and QTopo Base map
Copyright (c) State of Queensland (DNRME)
Created By: MM
Date: 28/12/2020
Version: 1
Page 11
4. Conclusion The Bushfire Attack Level (BAL) assessment has been prepared for the construction of a new dwelling house and associated outbuildings on the site at 327 Kinmond Creek Road, Cootharaba. The BAL is 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 meter squared. This forms the basis for establishing the requirements for construction to improve protection of building elements from attack by bushfire. The required minimum separation distances for each BAL was calculated in accordance with Method 2 of the Australian Standard AS3959:2018. A minimum separation distance of 16 m is required to achieve BAL-29, which is the recommended BAL based on acceptable outcomes for assessable development outlined in the State Planning Policy 2017 guidance material assessment benchmarks. Clearing of vegetation shall be required to achieve this minimum separation distance. It is recommended that the new dwelling be constructed to meet the specifications for BAL-29 outlined in Section 7 of AS3959:2018. In accordance with Sections 2.1 and 3.2.3 of AS3959:2018, this BAL applies to the entire building and to any attached or adjacent structures within 6 metres of the building. PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 11
Page 12
5. References
DILGP. (July 2017). State Planning Policy. Brisbane.
DNRME. (2020). Vegetation management regional ecosystem map (version 11.0). Brisbane,
Retrieved from Available from: http://www.dnrm.qld.gov.au/land/vegetation-
management/vegetation-maps/vegetation-map-request, .
DSDMIP. (2019). State Planning Policy - State interest guidance material: Natural hazards, risk
and resilience - Bushfire Department of State Development, Manufacturing,
Infrastructure and Planning Retrieved from
https://dsdmipprd.blob.core.windows.net/general/spp-guidance-natural-hazards-risk-
resilience-bushfire.pdf.
FPA Australia. (2017). Flamesol - AS 3959 calculatos and tools for bushfire consultants.
Retrieved from http://www.flamesol.com.au/
Noosa Council. (2020). Noosa Plan 2020. Retrieved from https://noo-prod-
icon.saas.t1cloud.com/Pages/Plan/Book.aspx?exhibit=Current.
Queensland Fire and Emergency Services. (2020). Catalyst Fire Management System.
Retrieved from https://catalyst.qfes.qld.gov.au/
Queensland Fire and Emergency Services (QFES). (2019). Bushfire Resilient Communities:
Technical Reference Guide for the State Planning Policy State Interest 'Natural
Hazards, Risk and Resilience' (October 2019). Queensland Fire and Emergency
Services.
Standards Australia. (2018). AS 3959-2009 Construction of Buildings in Bushfire-prone Area.
In Construction of Buildings in Bushfire-prone Area. Sydney: Council of Standards
Australia.
PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 12
Page 13
Appendix 1 – Proposed Development Concept Plan PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 13
Page 14
Approximate location of proposed buildings
N
6x8m Carport
13x7m Garage
House
[OCR of page images]
Approximate location of proposed buildings
6x8m Carport
Page 15
Appendix 2 – Flamesol Results PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 14 [OCR of page images] Green ‘TJ ape SOLUTIONS ENVIRONMENTAL CONSULTING Appendix 2— Flamesol Results PR20257_BAL_327 Kinmond Creek Rd, Cootharaba 14
Page 16
29/07/2020 Flamesol - powered by FPA Australia
Calculated July 29, 2020, 7:46 am (MDc v.4.8)
Cootharaba
Minimum Distance Calculator - AS3959-2018 (Method 2)
Inputs Outputs
Fire Danger Rate of
47 2.15 km/h
Index spread
Vegetation
Forest Flame length 18.17 m
classification
Surface fuel 54 °, 64 °, 72 °, 76 °,
31 t/ha Flame angle
load 78 ° & 84 °
6.58 m, 7.14 m, 7.17
Overall fuel Elevation of
35 t/ha m, 6.78 m, 6.5 m &
load receiver
3.52 m
Vegetation
n/a Fire intensity 38,888 kW/m
height
0.866, 0.844,
Effective
3° Transmissivity 0.8159999999999999,
slope
0.79, 0.777 & 0.719
0.6051, 0.4507,
Site slope 3° Viewfactor 0.3058, 0.2073,
0.1688 & 0.0456
Minimum
Flame width 100 m distance to < 12 m
40 kW/m²
Minimum
Windspeed n/a distance to < 16 m
29 kW/m²
Minimum
Heat of
18,600 kJ/kg distance to < 24 m
combustion
19 kW/m²
Minimum
Flame
1,090 K distance to < 34 m
temperature
12.5 kW/m²
Minimum
distance to < 42 m
10 kW/m²
Rate of Spread - Mcarthur, 1973 & Noble et al., 1980
tools.flamesol.com.au/MDc_output.php?CALCTITLE=Cootharaba&EFFECTIVESLOPE=3&SITESLOPE=3&VEGETATION=forest&FDI=47&SURF… 1/2