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Bushfire Hazard Assessment & Management Plan
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Log in to see the plans as drawn BUSHFIRE HAZARD ASSESSMENT &
MANAGEMENT PLAN v2
LOT 70 ON M37807
28 ELKHORN DRIVE
TEWANTIN
FOR
ELKHORN INVESTMENTS QLD PTY LTD
MAY 2016
Tel: (07) 5450 5984 / PO Box 9566 Pacific Paradise QLD 4564 / Email: [email protected]
ABN 44 851 168 122
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04
Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
DOCUMENT CONTROL
Bushfire Hazard Assessment & Management Plan
Client: Elkhorn Investments QLD P/L
Project ELK2016-04 BMP
Number:
Project: 1 into 11 Reconfiguration of a Lot
Site: Lot 70 M37807
28 Elkhorn Drive,
Tewantin, QLD
Version Date Distribution Key changes Author/s Approver
made
1 12th May N/A Nick Willis Joshua Lee
2016 Joshua Lee
2 23rd May Reference Joshua Lee Joshua Lee
2016 updated pan
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04
Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
TABLE OF CONTENTS
1.0 INTRODUCTION 3
1.1 NSC’S TEWANTIN & DOONAN NATURAL HAZARD: LANDSLIDE & FLOODING OVERLAY (MAP
OM9.3) 3
2.0 DEVELOPMENT PROPOSAL 3
3.0 SITE DESCRIPTION 4
3.1 TOPOGRAPHY 5
3.2 VEGETATION 6
3.2.1 VEGETATION UNIT 1 – OPEN EUCALYPT WOODLAND OVER MOWED GRASS. 7
3.2.2 VEGETATION UNIT 2 – OPEN EUCALYPT WOODLAND OVER SHRUBBY/GRASSY
UNDERSTOREY. 8
4.0 RISK ASSESSMENT METHODOLOGY 9
4.1 APPENDIX 3 OF THE STATE PLANNING POLICY 1/03 GUIDELINE: MITIGATING THE ADVERSE
IMPACTS OF FLOOD, BUSHFIRE AND LANDSLIDE 9
4.1.1 TOPOGRAPHY / SLOPE 9
4.1.2 ASPECT 9
4.1.3 VEGETATION 10
4.1.4 HAZARD RATING 11
5.0 RISK ASSESSMENT 11
5.1. SUB UNIT HAZARD AREAS 11
5.2 QUALITATIVE HAZARD ASSESSMENT 12
5.3 QUANTITATIVE HAZARD ASSESSMENT 14
5.3.1 FUEL LOAD ASSESSMENT 14
5.3.2 QUANTITATIVE MODELLING 15
5.3.2.1 Site Specific Input Parameters 15
5.3.2.2 Formulae 15
5.3.2.3 Modelled Output 15
6.0 BUSHFIRE IMPACT REDUCTION MEASURES 16
6.1 ASSET PROTECTION ZONE (APZ’S) 16
6.2 WATER SUPPLY 19
6.3 FIRE BREAKS 19
6.4 VEHICULAR ACCESS 19
6.5 FUTURE LANDSCAPING & REGROWTH 19
7.0 LEGISLATION AND OVERLAYS 20
7.1 NOOSA PLAN OVERLAY – SECTION 13.37 20
8.0 CONCLUSIONS 24
9.0 REFERENCES 25
APPENDIX 1 – SITE LAYOUT 26
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Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
1.0 INTRODUCTION
This Bushfire Hazard Assessment & Management Plan has been prepared to assess and
reduce the degree of potential bushfire hazard risk acting on Lot 70 on M37807, located at 28
Elkhorn Drive, Tewantin (referenced hereafter as ‘the site’). The site is the subject of a
proposed Reconfiguration of a Lot (1 into 11 lots) development application to be submitted to
Noosa Shire Council (NSC).
This assessment is to be used to assist Council with their decision making process.
1.1 NSC’s Tewantin & Doonan Natural Hazard: Landslide & Flooding Overlay (Map
OM9.3)
NSC’s 2009 Noosa Plan Natural Hazard: Landslide & Flooding Overlay Map for Tewantin &
Doonan depicts a Medium Bushfire Hazard Area extending across the eastern half of the site
(refer Plate 1). The Medium Hazard Area extend to the north and south and is associated
with the Noosa River riparian environs.
Plate 1 – Bushfire Prone Areas (Noosa Plan 2014)
In accordance with Part 13 Table 13.9 Bushfire Hazard Areas of the Noosa Plan a site specific
bushfire hazard assessment is required to determine the ‘on ground’ degree of bushfire risk
acting on the site. Determination of the degree of bushfire risk will allow Council to determine
whether the proposed development is appropriate for the site and that the proposed
development’s approval would not unacceptably endanger the lives of future occupants,
infrastructure and emergency services staff.
2.0 DEVELOPMENT PROPOSAL
The site is proposed to be subdivided into 11 residential lots. The proposed plan of
development is depicted on the site plan Drawing No. 15228.1 A by Project Urban dated
12/04/16 (refer Appendix 1).
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The proposed layout locates two new allotments to the south of the existing house, a further
two new allotments to the north-west of the existing house and the remaining six new
allotments to be located along the western boundary of the site.
3.0 SITE DESCRIPTION
The site is located in the north-east fringe of the Tewantin residential area and flanks the
Noosa River on its eastern boundary. The site measures 1.292 ha and is improved by a single
dwelling and a separate garage located adjacent to the centre east boundary. The grounds
of the site are host to a scattering native eucalypt and exotic trees over mown grass with
surface fuels generally absent to sparse.
The site is located within the Urban Footprint under the SEQ Regional Plan and is zoned as
Low Density Residential under the Noosa Plan.
Plate 2 depicts site conditions whilst Plate 3 depicts the site’s position in the landscape and
the extent of surrounding development and bushland areas.
Site
Plate 2 –Site conditions (Source: Google earth)
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Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
Site
Plate 3 –Site context (Source: Google earth)
3.1 Topography
The site is located on gently sloping east facing land that wanes into the Noosa River adjacent
to its eastern property boundary. The sits at approximately 10m ASL. Plate 4 depicts
topography conditions within and adjacent to the site.
Plate 3 – Site Topography (Source: NSC Interactive Mapping)
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin 3.2 Vegetation The site is characterised by a scattering of mature phase mixed eucalypt trees dominated by Eucalyptus tereticornis (forest red gum) over mown grass. Bushland shrub and groundcover strata are absent. No intact bushland areas are present within the site. Approximately 50m width of native vegetation is present flanking the eastern site boundary associated with the Noosa River riparian ecosystem and is host to open eucalypt forest over grassy to shrubby understorey bordered by a narrow band of mangroves below the tidal limit. The land parcel to the immediate west is host to approximately 1ha of selectively thinned mixed eucalypt woodland/ open forest over comprehensively cleared understorey. Figure F1 – Vegetation Units depicts the distribution of observed vegetation within the survey area which includes a 100m extension from the site. A description of the observed vegetation units is presented in Section 3.2.1 -3.2.2 © 2016 6
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KEY
VU1 - Open Eucalypt woodland over mown grass
VU2 - Open Eucalypt woodland over shrubby to grassy understorey
Development Site
PROJECT: BUSHFIRE REPORT FIGURED DIMENSIONS TO SCALE : - SEE INSERT DRAWN J.A.L. Figure No. BMPF1 - v1
APPLICATION: SITE: BE READ IN PREFERENCE
28 ELKHORN DRIVE
DEVELOPMENT PERMIT TO TO SCALING. SHEET NO 1 OF 3 TITLE: VEGETATION COMMUNITIES
RECONFIGURE A LOT (1 INTO 11 LOTS) TEWANTIN QLD DATE : - 23.05.2016
CANCELLING LOT 70 ON M37807
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Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
3.2.1 Vegetation Unit 1 – Open Eucalypt Woodland over mowed grass.
Vegetation Unit 1 represents the sole vegetation unit within the site and also occupies the site
to the immediate west where slightly greater stem density is present.
This community exhibits an average canopy height of 26m with Projective Foliage Canopy
Cover (PFCC) of 15%. Overall, the vegetation community displays indicative species diversity
of Regional Ecosystem 12.5.3 which is described as ‘Eucalyptus racemosa subsp. racemosa
woodland with Corymbia intermedia, E. siderophloia +/- E. tindaliae, E. resinifera, E. pilularis,
E. microcorys, Angophora leiocarpa. Melaleuca quinquenervia is often a prominent feature of
lower slopes.
The vegetation was observed to be of moderate age (40-60 years) and is dominated by
Eucalyptus tereticornis with Corymbia intermedia sub-dominant. Pinus elliottii (exotic) is co-
dominant in the lot to the west of the site. Small populations of Melaleuca quinquenervia and
Lophostemon suaveolens were also represented. The midstorey is absent and the
groundcover dominated by a mix of native and exotic grasses subject to regular mowing. Plate
4 depicts typical conditions within VU1.
Plate 4 – VU1 Open Eucalypt Woodland over grassy understorey
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3.2.2 Vegetation Unit 2 – Open Eucalypt Woodland over shrubby/grassy understorey.
Vegetation Unit 2 is present flanking the eastern site boundary and occupies the western bank
of the Noosa River for considerable distance to the north and south of the site. The unit
averages only 40m east to west width and is differentiated from VU1 by the presence of a
shrubby understorey species assemblage.
This community exhibits an average canopy height of 26m with Projective Foliage Canopy
Cover (PFCC) of 15%. Overall, the vegetation community displays indicative species diversity
of Regional Ecosystem 12.5.3 which is described as ‘Eucalyptus racemosa subsp. racemosa
woodland with Corymbia intermedia, E. siderophloia +/- E. tindaliae, E. resinifera, E. pilularis,
E. microcorys, Angophora leiocarpa. Melaleuca quinquenervia is often a prominent feature of
lower slopes.
The vegetation was observed to be of moderate age (40-60 years) and is dominated by
Eucalyptus tereticornis with Corymbia intermedia sub-dominant. Melaleuca quinquenervia
and Lophostemon suaveolens become increasingly dominant on the lower slopes. The shrub
layer is characterised by Glochidion sumatranum, Alphitonia excelsa, Cupaniopsis
anacardioides and Lophostemon suaveolens. The groundstorey is dominated by Imperata
cylindrica (Blady Grass) and Smilax australis with a mix of native and exotic grasses and ferns
present. A narrow band of mangrove species flanks the edge of VU2 and is restricted to the
tidal limit. Mangrove communities are considered virtually fireproof and therefore they have
been absorbed into VU2 rather than being identified as a discrete vegetation unit requiring
assessment.
Plate 5 depicts typical conditions within VU2.
Plate 5 – VU2 Mixed Eucalypt Open Forest/ Woodland over shrubby/grassy understorey
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4.0 RISK ASSESSMENT METHODOLOGY
The level of bushfire hazard risk acting on the site was assessed in accordance with the
methodology prescribed in PSP1 of the Noosa Plan which specifies the assessment be
undertaken in accordance with the now repealed Appendix 3 of the State Planning Policy 1/03
Guideline: Mitigating the Adverse Impacts of Flood, Bushfire and Landslide
Several investigative tools were utilized to determine the site specific bushfire hazard risk
including:
Review of local aerial photography,
Review of site and local topography,
Review of DNRM’s Vegetation Management Support Map, and
Inspection of the site in May 2016.
4.1 Appendix 3 of the State Planning Policy 1/03 Guideline: Mitigating the Adverse
Impacts of Flood, Bushfire and Landslide
Appendix 3 of SPP 1/03 utilizes a scoring system to assess bushfire risk based on three
loading factors: vegetation type, site aspect and slope. The total of all three loading factors is
used to determine a site’s severity of bushfire hazard.
4.1.1 Topography / Slope
Physical conditions such as slope and terrain can influence important fire behaviour
characteristics such as wind speed and direction, and the rate of spread of fire. Fire is known
to double its rate of spread with each 10% increase in slope, up to 30% (Webster 2000). Slope
also has the effect of ‘tipping’ a flame to an acute angle as it travels upslope, which brings a
flame, and fire front, closer to unburnt vegetation. As a result, tipping facilitates the preheating
of vegetation and can make vegetation combust and burn quicker (Webster 2000). Therefore,
it is desirable to locate developments within bushfire prone areas on terrain which will not
significantly accelerate/intensify fire behaviour (i.e. steep slopes).
Table A3.2: Hazard score for slope has been directly extracted from SPP1/03 and depicts the
hazard scores relevant to slope influence.
4.1.2 Aspect
Sites with west to north aspects are considered at greatest risk to potential bushfire impacts,
given their direct frontage to hot and dry northerly to westerly winds most commonly
associated with bushfire outbreaks.
Table A3.2: Hazard score for aspect has been directly extracted from SPP1/03 and depicts
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin the hazard scores relevant to aspect influence. 4.1.3 Vegetation Vegetation community composition and structure can significantly influence the rate at which dry fuel load accumulates and becomes available to burn. The fire behaviour characteristics of differing vegetation communities is depicted below in Table A3.1 Hazard scores and associated fire behaviours for various vegetation communities, from SPP1/03. © 2016 10
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4.1.4 Hazard Rating
Table 1 specifies the range of prescribed bushfire hazard severities and their respective total
hazard scores.
Table 1 – Hazard Score and Corresponding Severity of Bushfire Hazard (Table A3.4 of
Appendix 3 of the SPP 1/03)
Total Hazard Score Severity of Bushfire Hazard
13 or greater High
6 – 12.5 Medium
1 – 5.5 Low
Note – Land within 50m of a Medium severity bushfire hazard area is included within a Medium
severity bushfire hazard area and land within 100m of a High severity bushfire hazard area is
included within a High severity bushfire hazard area.
5.0 RISK ASSESSMENT
5.1. Sub Unit Hazard Areas
The bushfire risk assessment comprised analyses of the site’s characteristic bushfire risk
loading factors. As a result of variable topography, vegetation extent and composition, the
site and immediately surrounding areas were subdivided into sub-units of similar
characteristics. The bushfire risk assessment was then performed on each sub-unit.
Delineation and hazard analysis of the sub-units is presented in NCES Drawing No BMP F2 -
Sub-Units.
In accordance with the Appendix 3 SPP 1/03 scoring system, and factoring in standard 50m
safety buffers adjacent to Medium bushfire hazard areas, the eastern half of the site is
occupied by a Medium Bushfire Hazard Area with the balance of the site captured in a non-
bushfire prone area (refer NCES Drawing No F3 - Overall Hazard Areas).
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SUB UNIT HAZARD ANALYSIS TABLES SUB UNIT HAZARD AREA MAP
KEY LOW HAZARD AREAS SUB UNITS PROJECT: BUSHFIRE REPORT FIGURED DIMENSIONS TO SCALE : - SEE INSERT DRAWN J.A.L. Figure No. BMP F2 - v1
APPLICATION: SITE: BE READ IN PREFERENCE
28 ELKHORN DRIVE
MEDIUM HAZARD AREAS DEVELOPMENT SITE DEVELOPMENT PERMIT TO
RECONFIGURE A LOT (1 INTO 11 LOTS) TEWANTIN QLD TO SCALING. DATE : - 23.05.2016 SHEET NO 2 OF 3 TITLE: SUB UNITS
CANCELLING LOT 70 ON M37807
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OVERALL HAZARD AREA MAP
KEY LOW HAZARD AREAS DEVELOPMENT SITE
PROJECT: BUSHFIRE REPORT FIGURED DIMENSIONS TO SCALE : - SEE INSERT DRAWN J.A.L. Figure No. BMP F3 - v1
APPLICATION: SITE: BE READ IN PREFERENCE
MEDIUM HAZARD AREAS DEVELOPMENT PERMIT TO
RECONFIGURE A LOT (1 INTO 11 LOTS)
28 ELKHORN DRIVE
TEWANTIN QLD
TO SCALING. DATE : - 23.05.2016 SHEET NO 3 OF 3 TITLE: OVERALL HAZARD AREAS
CANCELLING LOT 70 ON M37807
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5.2 Qualitative Hazard Assessment
The vegetation within the site represents limited risk of ignition or potential for transmission of
fire due to the sparseness of the canopy vegetation, the lack of dry shrub ladder fuels and the
lack of surface and near surface fuels. The hazard acting on the site therefore is restricted to
low intensity grassfire risk within the site and potential for impact from off-site forest hazard
sources.
Two immediate off-site hazard sources and a combined landscape scale hazard source
present a degree of bushfire risk to the site. The immediate off-site hazard sources comprise
the Noosa River riparian environs to the east and the eucalypt woodland contained within the
adjoining allotment to the west (i.e. Lot 6/RP149498). The landscape scale hazard source
comprises the extensive Great Sandy National Park open forest vegetation to the east and
north to north-west of the site and the Moorindil Reserve open forest vegetation to the north-
west of the site. Plate 5 depicts the extent and position of the off-site hazard sources acting
on the site.
Great Sandy NP
Site
Moorindil Reserve
Plate 5 – Available open forest fire pathways (Source: Google Earth)
A narrow, north- south aligned potential fire pathway is present flanking the eastern site
boundary in the form of mixed open eucalypt forest/woodland on the west bank of the Noosa
River. The limited width of the unit at approximately only 40m combined with observed patchy
surface fuel loads due to slope run-off, past clearing and pedestrian traffic act to constrain the
hazard risk of the disturbed bushland unit. The vegetation is bordered by a virtually fireproof
mangrove community and then the Noosa River and therefore has limited opportunity to
transmit fire other than along the bank of the river. The moderate to steep side slope of the
bank exhibits insufficient slope length to significantly influence fire movement.
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin A second potential fire pathway exists to the west of the site, which under predominant regional fire weather winds from the north to west, could carry a fire onto the site. The vegetation to the west comprises Eucalyptus tereticornis and Corymbia intermedia woodland over cleared understorey conditions (mowed) which substantially reduces the available surface fuels to support fire. The western part of the adjoining allotment is host to stands of slash pine which offer flammable surface fuels (pine needles and cones) and therefore represents a possible fuel source to support a low intensity fire. It is noted the site is comprehensively buffered from forest fire ingress from the north, south and west beyond the immediate flanking vegetation. Therefore, apart from the low risk of fire entering the site from the east it is most at risk of ember and advance spotting attack from a fire burning further afield to the north to north-west within the expansive Great Sandy National Park open forest vegetation. Post development conditions within the site will reduce the capacity for intact bushland to regenerate on the site and therefore protection from ember and advance spotting relies on building construction standards and general yard maintenance. The risk of a fire burning from east to west and or south to north toward the site is generally considered low as such weather conditions are rarely associated with hazardous bushfire weather conditions on the Sunshine Coast. The risk of severe fire developing from these directions is constrained by several factors including fragmentation resulting from the presence of existing clearings for housing and roadways, the aquatic environs of Noosa River, flanking low flammability mangrove communities and the low likelihood of a fire developing under southerly or easterly winds, which generally facilitate high humidity, cooler land temperatures and rainfall periods. The site’s position in an urban landscape offers emergency services direct and efficient access to the site which, combined with supply of pressurized town water, infers excellent capacity to defend fire at the site. Overall the Medium and Low hazard rating scores attributed to the investigation area using the SPP methodology is considered warranted. The inclusion of hazard reduction measures into the proposed plan of development is deemed appropriate given the continuous expanse of flammable open forest vegetation flanking the Noosa River further to the north, east and west of the site and therefore the risk of ember attack impacting the site and flaring up a fire in the local vegetation units. © 2016 13
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5.3 Quantitative Hazard Assessment
5.3.1 Fuel Load Assessment
An assessment of the fuel load contained within the bushland units within and bordering the
site was undertaken as per Gould et al. 2007, and consisted of measuring the amount of fuel
present within the various layers of the assessed vegetation communities. The location of the
fuel load plots is shown in Plate 6 with the results presented in Table 2.
Plot 2
Plot 1
Plate 6 – Location of Fuel Load Assessment Plots (Source: Google Earth)
Table 2 – Fuel Assessment
Plot 1 – Plot 2 -
VU1 VU2
Surface Fuel Depth (mm) 0 15
Hazard Score 0 2
Available Fuel (t/ha) 0 6-10
Near-Surface Fuel Hazard Rating Nil Moderate
Hazard Score 0 2
Available Fuel (t/ha) 0 2
Elevated Fuel Hazard Rating 0 High
Hazard Score 0 3
Available Fuel (t/ha) 0 2-3
Bark Hazard Score 1 1
Available Fuel (t/ha) 1 1
Slope (degrees) 0 10
Tree Height (metres) 26 26
Available Fuel (t/ha) 1 11-16
Table 2 illustrates the impact the managed understorey conditions within VU1 has on total
available fuel loads hence fire risk. It is noted that the overall tonnage per hectare in VU2 at
11-16 t/ha is currently lower than the standard input tonnage used for open eucalypt forest in
the AS3959-2009 assessment methodology, which uses 35 t/ha for such forest types. It is
therefore likely that fuel loads will continue to increase within the offsite bushland in the
absence of natural fire and/or controlled fires at the site.
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin 5.3.2 Quantitative Modelling Quantitative modelling of the potential bushfire conditions that may be experienced within the vegetation fronting the eastern site boundary has been undertaken to assist in quantifying the potential risk of impact to the proposed development. The models used comprise industry standard bushfire equations. 5.3.2.1 Site Specific Input Parameters Slope = 5º inclining toward site FDI = 50 (Sunshine Coast) Surface Fuel Load = 12 t/ha, Total Fuel Load = 16 t/ha (Source: Derived from onsite Fuel Load Assessment for VU2 – See Section 5.3.1) 5.3.2.2 Formulae Rate Spread (R) R = 0.0012 *FDI*w *exp (0.069*slope) (Noble et al. 1980) Where: R = rate of spread (km/hr) FDI = Fire Danger Index W = surface fuel load (t/ha), Slope = slope of the land with vegetation (degrees) Fire Intensity I = H*W*R/36 (Byram 1959) Where: I = fire intensity (kW/m) H = heat of combustion (kJ/kg), approximated as 18,600 kJ/kg R = rate of spread (km/hr) W = overall fuel loads (t/ha), Flame Length Lf = (13R+0.24W)/2 (RFS PBP 2001) Where: Lf = flame length (m) R = rate of spread (km/hr) W = overall fuel loads (t/ha), 5.3.2.3 Modelled Output (R) = 0.0012 x FDI (50) x Surface Fuel Load (12) x exp (0.069 x slope (5)) = 1.01km/hr (I) = 18600kj/kg x 16 x 1.01 / 36 = 8.349 kW/m Lf = (13 x 1.01 + 0.24 x 16)/2 = 8.48m The results illustrate that the identified Medium hazard vegetation along the eastern boundary of the site represents potential to exhibit moderate severity bushfire conditions at the time of assessment. Flame length results infer sufficient flame heights could be output to facilitate a crown fire within the open eucalypt forest vegetation. It is noted a slope of 5⁰ was selected as the slope input parameter and that a fire burning along the river bank would predominantly burn across the contour which is equivalent to near flat conditions. A five-degree slope increases forward rate of spread by 30% which would have a corresponding significant influence upon the fire intensity and flame length output results. Therefore, the output results are considered somewhat exaggerative. Wind velocities, atmospheric conditions, and time since last fire would also affect bushfire behaviour, either increasing or decreasing potential bushfire severity. © 2016 15
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6.0 BUSHFIRE IMPACT REDUCTION MEASURES
The following section describes bushfire risk reduction measures to be incorporated into the
proposed development to reduce the risk of bushfire impact to people and property.
Implementation of the identified measures is not implied nor intended to advocate that
residents remain on the site during a bushfire event, nor that people and property will be
protected from bushfire impact. The measures are intended to reduce the potential severity
of bushfire impact to the development zone and not prevent actual bushfire impact.
The scope of referenced management measures have been derived from:
Noosa Plan Bushfire Hazard Overlay Code;
Appendices 5B & 8 of State Planning Policy 1/03 ‘Mitigating the Adverse Impacts of
Flood, Bushfire and Landslide, 2003;
Bushfire Hazard Planning in Queensland (1993). Queensland Fire & Rescue Authority,
Brisbane; and
AS3959-2009 Construction of Buildings in Bushfire Prone Areas.
6.1 Asset Protection Zone (APZ’s)
APZ’s provide a defensive tool to assist in the reduction of potential bushfire impact to people
and property situated in bushfire prone areas. For illustrative purposes Plate 7 depicts the
concept of protection zones about dwellings in bushfire prone areas.
Plate 7 – Bushfire Protection Zones
The proposed allotments within the east of the site are mapped within a Medium Bushfire
Hazard Area on Noosa Council’s Bushfire Hazard Overlay Map and have been confirmed as
being exposed to potential low severity bushfire impact. Therefore, the future buildings in the
east of the site require adequate separation from the hazardous vegetation contained within
the adjoining Noosa River foreshore reserve. It is noted that no hazardous intact bushland
units are present within the development site.
The Noosa Plan Bushfire Hazard Overlay Code stipulates that lots less than 2,500m2
maximise separation of buildings from hazardous vegetation. All proposed lots are less than
2500m2 in area. The Australian Standard 3959-2009 Construction of Buildings in Bushfire
Prone Areas can provide guidance on setbacks. Designation of the site within a Bushfire Prone
Area on Noosa Plan’s Bushfire Hazard Overlay Map triggers building design assessment
under Australian Standard 3959-2009 Construction of Buildings in Bushfire Prone Areas.
AS3959 (2009) provides minimum construction requirements for new dwellings in designated
Bushfire-Prone Areas. The construction requirements are intended to improve the
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin performance of buildings subjected to burning debris, radiant heat or flame contact. New buildings in designated bushfire prone areas must be built to the Bushfire Attack Level construction standard relevant to the building site as identified by the Standard. In this case it is proposed to adopt setbacks which would result in the buildings on the site being sited in no higher category than BAL 29 under Australian Standard 3959-2009 Construction of Buildings in Bushfire Prone Areas. BAL 29 is deemed acceptable in light of the very low likelihood of a significant fire occurring in the easterly adjacent vegetation. In all cases the siting of buildings in BAL Flame Zone category should be avoided wherever possible. Table 2.4.5 from Amdt 1 of AS3959-2009 details required setbacks to vegetation to achieve the different BAL categories (refer below). Type B ‘Woodland’ has been selected as the dominant vegetation classification adjacent to the eastern site boundary and downslope 5-10⁰ conditions selected as the dominant slope conditions. © 2016 17
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin The BAL 29 column in Table 2.4.5 above illustrates that a setback range of 13 - <19m is required to achieve BAL 29 for the proposed new dwellings. The positioning of new dwellings >13m from the eastern site boundary vegetation will provide a suitable outcome which balances fire safety with the practical low threat of direct flame contact from surrounding vegetation. It is noted proposed Lot 9 provides 22m to 25m separation between new dwellings on lots 7, 8, 10 and 11 and the adjoining reserve vegetation. The new dwellings would therefore achieve the recommended maximum BAL 29 setback and would in fact be positioned in BAL 19 (19- <28m). It is therefore considered the subject plan of development provides satisfactory building to vegetation setbacks based on current site conditions. It is important to note continued fuel load management in Lot 9 is necessary to maintain the current low fuel load conditions in the east of the site and to prevent bushland encroachment © 2016 18
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04
Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
toward the proposed new dwellings. Any revegetation works in Lot 9 would be
counterproductive to mitigating bushfire hazard and would require commensurate
repositioning of the dwellings on Lots 7, 8, 10 and 11 further to the west.
The above setback recommendations may require alteration should site conditions and/or the
AS3959-2009 BAL calculation methodology change in the future. The respective landowners
are to be responsible for ensuring the measures prescribed herein are applied and stay up to
date with site conditions and industry standards. Landholders/managers should therefore
liaise with QFRS at regular intervals (i.e. recommended at least every 5 years).
6.2 Water Supply
The availability of a reliable water supply for fire fighting purposes is a vital tool in the defence
of bushfire impact. Reticulated water supply will be available to the proposed development,
which will provide a readily accessible on-site emergency water supply in accordance with
Council’s Bushfire Hazard Overlay Code .
6.3 Fire Breaks
The provision of fire breaks and fire trails within a site located in a bushfire prone area offers
an important bushfire defence measure to assist in reducing the risk and severity of bushfire
ingress onto and through a site. The lack of significant sized bushland units immediately
bordering the proposed development site infers the need to incorporate fire break trails on site
perimeters is unnecessary.
6.4 Vehicular Access
New developments in bushfire prone areas should be serviced by safe access/exit points for
both residents and emergency services personnel. The development plan includes the
construction of a new north-south aligned internal roadway accessed directly from Elkhorn
Avenue on the site’s southern boundary.
Consideration of road design for bushfire safety purposes is not deemed applicable given that
the development will predominantly be accessed over low grades through an area that is
largely devoid of hazardous vegetation. Future housing on the site will buffer the roadway
from possible fire impacts hence the risk of access/egress becoming constrained during a
bushfire is deemed low.
6.5 Future Landscaping & Regrowth
To reduce the potential for bushfire impact to buildings, structures and occupants as a result
of future regrowth and landscaping works within the site, it is recommended:
Future landscaping works/plantings exclusively incorporate locally indigenous, low
flammability species, and
Landholders should consult their local native plant nursery for suitable species
selection regarding non-fire promoting vegetation species.
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Bushfire Hazard Assessment & Management Plan – v2 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin 7.0 LEGISLATION AND OVERLAYS 7.1 Noosa Plan Overlay – Section 13.37 The proposed development is considered assessable development and therefore is assessable against the assessment criteria contained within Section 13.37 of the Bushfire Hazard Overlay Code which has been reproduced as Table 4 below. © 2016 20
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Bushfire Hazard Assessment & Management Plan - v1 NCES REF: NEX 2016-03
Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
Table 4 - Bushfire Hazard Overlay Code (Reconfiguring a Lot)
SPECIFIC OUTCOMES PROBABLE SOLUTIONS PROPOSED SOLUTION
General
O10 The safety of people and property are S10.1 The proposed lots are not located on land that is subject to Medium or High
maintained by Bushfire Hazard on overlay maps OM1.4-OM9.442;
OR
a) Locating house site areas and other S10.2 The proposed lots are sited on land determined as low bushfire risk by a site S10.2 The development site has been identified to
sensitive uses on that part of the land specific bushfire hazard assessment. be captured in a Low hazard sub unit.
least affected by the bushfire hazard; AND
and S10.3 Additional lots are not created where their only vehicular access route is through a S10.3 Vehicular access to the new lots is via a
b) fire mitigation methods are used that are Medium or High Bushfire Hazard area shown on overlay maps OM1.4-OM9.4 new road to be constructed through a Low Hazard
adequate for the Potential Bushfire Area identified on OM1.4 - 9.4.
Hazard rating of the individual site,
having regard to –
i. vegetation type;
ii. slope;
iii. aspect;
iv. on-site and off-site fire hazard
implications of the development;
v. bushfire history;
vi. conservation values of the site; and
vii. ongoing maintenance.
Firebreaks and fire access tracks S11.1 Firebreaks are provided by— Alternative Solution Proposed. The low threat of
O11 Firebreaks or fire access tracks provide— a) a cleared road reserve not less than 20m wide located around the perimeter fire on the site post development does not warrant
a) adequate access for fire fighting and of the subdivision, between the created lots and surrounding vegetated lands; inclusion of fire break trails along the eastern or
other emergency vehicles; and OR western boundaries of the site.
b) adequate width to minimise the risk of b) b) fire access tracks (may be in the form of an access easement) between the
fire crossover. created lots and surrounding vegetated lands that—
i. are a minimum cleared width of 6m;
ii. have a formed pavement;
iii. have access at each end and in other locations where necessary;
iv. have passing areas and turning areas;
v. have clearly identified access points for emergency vehicles; and
vi. are located on public land or within access easements that are granted in
favour of the Sunshine Coast Regional Council and the Queensland Fire and
Rescue Service.
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Bushfire Hazard Assessment & Management Plan - v1 NCES REF: NEX 2016-03
Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
Road network S12.1 Cul-de-sacs or no-through roads are not used in the street network unless— Alternative Solution Proposed. The low threat of
O12 Roads provide for the safe and effective a) a perimeter road reserve with a minimum reserve width of 20m and a formed fire on the site post development indicates inclusion
evacuation of users of premises and access by width of not less than 6m is provided; or of the proposed cul-de-sac design is acceptable.
Emergency services. b) cul-de-sacs or no-through roads are provided with fire trails or access Egress from the site would be in a southerly
easements, capable of being navigated by conventional vehicles, that link to direction away from the likely direction of fire
through roads (see Figures 13.3 and 13.4); encroachment toward the site (i.e. from the north-
AND west).
S12.2 Roads have a maximum grade of 1 in 8 (12:5%).
Figure 13.3—Consistent road network and lot layout
Figure 13.4—Inconsistent road network and lot layout
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Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin
Lot design S13.1 Each residential lot— S13.1 (d) All lots are to be less than 2500m2 in
O13 Lot design and building siting minimises area. Setbacks have been recommended which
bushfire hazard to people and property having a) includes a house site area, identified on the plan of subdivision; result in all buildings being sited no closer than 13m
regard to slope, aspect, existing vegetation and b) is of sufficient size and dimensions to accommodate a dwelling and from the Noosa River foreshore reserve vegetation
adequate separation from hazardous vegetation ancillary buildings and use areas; and in no higher than BAL 29 under AS3959-2009.
c) for lots more than 2,500m—
i. conform with the principles for house site numbers 1, 2 or 3 shown in
Figure 13.5; and
ii. are separated from hazardous vegetation for a distance the
minimum of 1.5 times the predominant mature canopy height
or 10m, whichever is the greater; and
d) for lots less than 2,500m2, maximise separation of buildings from
hazardous vegetation.
S13.2 House sites are on level ground and
S13.2 Residential lots are designed so that their size and shape allow for efficient provided with short length driveway access to the
emergency access to buildings for fire fighting appliances (e.g. by avoiding long narrow proposed new internal road. The layout is
lots with long access driveways). considered compliant with S13.2
Figure 13.5—House sites in bushfire hazard areas
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Bushfire Hazard Assessment & Management Plan - v1 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin 8.0 CONCLUSIONS Assessment of Lot 70 on M37807 located at 28 Elkhorn Drive, Tewantin, in accordance with the Noosa Plan Bushfire Hazard Overlay Code scoring system has identified that the east of the site is captured within a Medium Bushfire Hazard Area with the balance of the site captured in a Low Bushfire Hazard Area. Development of the site is proposed within the identified Medium Bushfire Hazard Area, hence inclusion of hazard reduction measures into the proposed plan of development is warranted. Numerous bushfire reduction measures have been recommended herein, which if adopted, will assist in the protection of people and property during a bushfire emergency. Overall the proposed development design as detailed in the plan of development, in combination with recommendations referenced herein, is deemed suitable for the site and with respect to providing a reasonable level of protection for people and property on the site. Further the plan of development is considered compliant with the provisions of the Noosa Plan Bushfire Hazard Overlay Code. Bushfire is an extremely serious and often unpredictable phenomenon that requires serious preparatory planning and decision making to avoid potential damage to infrastructure and or loss of life. All recommendations made herein have been formulated based on site conditions at the time of writing and therefore may not be appropriate in the event site conditions change over time. Implementation of the bushfire mitigation measures referenced herein is not implied nor intended to advocate that residents remain on the site during a bushfire event nor that people and property will be protected from bushfire impact. The measures are intended to reduce the potential severity of bushfire impact to the development zone and not prevent actual bushfire impact. It is strongly recommended site occupants seek regular advice from local fire authorities to ensure the subject recommendations remain appropriate in future years. The local urban fire authority is the Noosa Heads Urban Fire Brigade located at 2 Langura St, Noosa Heads. Phone: (07) 5473 8484 The nearest Rural Fire Brigade is the Tinbeerwah Fire Brigade located at Sunrise Road, Tinbeerwah. Phone: 07 5442 6999 The first call in the event of a bushfire emergency should always be ‘000’. Joshua Lee Principal Environmental Scientist B. Sc. AES © 2016 24
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Bushfire Hazard Assessment & Management Plan - v1 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin 9.0 REFERENCES Bradstock, Gill & Williams. 2012. Flammable Australia: fire regimes, biodiversity and ecosystems in a changing world. CSIRO, Collingwood, Victoria. Department of Emergency Services (2003). Appendix 3 & 8 State Planning Policy 1/03 Guideline: ‘Mitigating the Adverse Impacts of Flood, Bushfire and Landslide’. Brisbane. Gould, McCaw, Cheney, Ellis & Matthews. 2007. Field Guide – Fuel assessment and fire behaviour in dry eucalypt open forest. Ensis-CSIRO, Canberra, ACT and Department of Environment and Conservation, Perth, WA. Southeast Queensland Fire and Biodiversity Consortium – Operational Manual. Bushfire Hazard Overlay Code. Noosa Plan 2009. Noosa Council. Webster. 2002. The Complete Bushfire Safety Book. Random House (Aust) Pty Ltd. © 2016 25
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Bushfire Hazard Assessment & Management Plan - v1 NCES REF: ELK 2016-04 Lot 70 on M37807 – 28 Elkhorn Drive, Tewantin APPENDIX 1 – SITE LAYOUT © 2016 26
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/ RPIS6 715 90°00'40" 0 5 10 IS 20 25 30 60 Metres OOO I I I I I ] Original Scale 1:600 20-189 ( 21751 2 605m? 8 ' 6 vo x 12-215 iy ‘ Pathway 10-277 3° So s \\ Q Q 2 ® 713m . 5 = House 6 aL 33-498 FEL I-66 RP/49498 § " 9 XN 633m? sl - 8 4249m » 4/ 6 71am? — B y a 43-444 \ a \ 3 S 2 x = 759M 2 5! S \ 45-888 x 80 lm? 1 y w Q 270°0I 26 7 13 /8 RPI49497 RPIB9883 RPIE9883 RPI89883 PROJECT / URBAN Sunshine Coast P | 07 5443 2844 f lllo7 5443 7146 Brisbane P | o7 3257 4371 f llo7 3666 0641 [email protected] www.ProjectUrban.com.au Project Urban Pty Ltd ACN 608 895 923 ABN 97 608 895 923 CLIENT ELKHORN INVESTMENTS (QLD) PTY LTD PROJECT PROPOSED SUBDIVISION OF LOT 70 ON M37807 PARISH OF NOOSA AMENDMENTS DATE O;/m|m!/o/o|o|> DESIGNED DATE SURVEYED DATE DRAWN AMR DATE 120416 NOTES CONTOURS DERIVED FROM KHA FIELD SURVEY CONTOUR INTERVAL = 0.50m THIS IS A PROPOSAL PLAN ONLY AND |S SUBJECT TO LOCAL AUTHORITY SUBDIVISION APPROVAL AND ENGINEERING CONSTRAINTS. AREAS AND DISTANCES ARE APPROX ONLY AND SUBJECT TO FINAL SURVEY COMPUTER FILE 15228_PRO SUB_120416 SCALE 1:600 SHEET 1 OF 1 SHEETS DRAWING No AMEND 15228.1 A /