4.4 Terrestrial Fauna
4.4.2 Database Searches
Searches of DPaW’s NatureMap database and the Commonwealth Department of the Environment’s Protected Matters Search Tool were undertaken to identify species of conservation significant fauna recorded or likely to occur within a 5 km radius of the site using the search coordinates 115°57ʹ33ʺE, 31°51ʹ29ʺS (Appendix 3).
Based on ecological requirements, known distributions and the type and quality of fauna habitats, the key species that could potentially be directly impacted by future residential development of the site, include:
forest red tailed black cockatoo (Calyptorhynchus banksii naso)
Carnaby’s Black-Cockatoo (Calyptorhynchus latirostris)
Baudin’s black cockatoo (Calyptorhynchus baudinii).
Additionally, the Bennett Brook and foreshore environments may support the following conservation significant species:
southern brown bandicoot (Isoodon obesulus / Isoodon obesulus subsp. fuscinventer) (Priority 5)
water-rat (Hydromys chrysogaster) (Priority 4)
rainbow bee-eater (Merops ornatus) (Migratory).
Given the 120 ha extent of Bush Forever Site 305 – Bennett Brook, Eden Hill to West Swan, which includes the Bennett Brook and foreshore environments (Figures 1 and Figure A), and the Bush Forever Site’s direct linkages to Bush Forever Site 304 – Whiteman Park in the north and Site 302 – Swan River and Jane Brook in the east which form part of contiguous and fragmented bushland / wetland linkage, it is considered unlikely that the southern brown bandicoot, water rat or rainbow bee-eater would be significantly impacted by the proposed development (if present in the Bennett Brook and foreshore environments adjacent to the site).
4.4.2.1 Black Cockatoo Habitat
The Level 1 Flora and Vegetation Survey and Significant Tree Inventory (RPS 2015) identifies that there were five Eucalyptus gomphocephala, eight Corymbia calophylla and two Eucalyptus marginata recorded (Appendix 2).
It is considered likely that the native trees may be utilised opportunistically by black cockatoo species moving through the Bennett Springs landscape, however given that the native trees occur in a predominantly cleared landscape it is considered unlikely that the trees would be utilised on a permanent basis.
Potential black cockatoo habitat on the site comprises of approximately 0.31 ha of foraging habitat with one Eucalyptus marginata tree, within Lot 46, was identified as having hollows (Figure 7). Figure 7 indicates that approximately 0.10 ha of potential foraging habitat, and the one Eucalyptus marginata tree with hollows, is located within the 50 m buffer of Conservation Category wetland (UFI15259).
Potential black cockatoo habitat within the Conservation Category wetland’s 50 m buffer will be retained by the LSP (Figure 3). Scattered Eucalypt trees have also been retained within POS areas where possible.
The implementation of the LSP will result in the loss approximately 0.21 ha of potential foraging habitat from the site (Figure 7).
It is considered that the implementation of the LSP will not result in a significant impact, as defined under the Matters of National Environmental Significance: Significant Impact Guidelines 1.1 (Commonwealth of Australia 2013) occurring to black cockatoos.
5.0 WATER-THEMED FACTORS
5.1 Hydrological Processes
5.1.1 Groundwater
The site is located within the Swan and Mirrabooka Groundwater areas. Both are extensively allocated with some small available volumes, predominately in the superficial aquifers (TME 2011).
Groundwater levels fluctuate seasonally with the highest groundwater levels, recorded during winter, being close to the ground’s natural surface (TME 2011).
Groundwater flow through the West Swan “West” general area is eastwards from the Gnangara mound to the Swan River. There is however localised deviations from this due to the effects of other drains and waterways such as Bennett Brook. This results in groundwater moving generally through the site in a south-westerly direction towards the Bennett Brook. Groundwater level contours across the West Swan “West” general area range from 19 m AHD down to 13 m AHD (TME 2011).
5.1.1.1 Groundwater Quality
Groundwater pH below the site is likely to be generally slightly acidic. The levels of nutrients in groundwater are likely elevated above the targets of the Healthy Rivers Action, which are 0.1 mg/L total phosphorous and 1.0 mg/L total nitrogen (TME 2011).
5.1.2 Surface Water
In relation to the site, the key surface water feature is the Bennett Brook, which lies adjacent to the site’s western boundary. Bennett Brook drains a total catchment of 69 square kilometres (km2). Where Bennett Brook first borders the site its catchment is approximately 40.7 km2. The site is approximately 2.5% of the total catchment (TME 2011).
5.1.2.1 Flood Levels
TME (2011) identifies that the 100 year Average Recurrence Interval (ARI) flood fringe of the Bennett Brook extends to the 18.65 m AHD contour where Bennett Brook borders the site. The flood level drops to 10.84 m AHD along the southern boundary of the site, prior to discharging under Reid Highway. The water then drops again to 9.93 m AHD, shortly after Reid Highway (TMW 2011).
Figure 8 shows the extent of the Bennett Brook 100 year ARI flood plain in relation to the site.
5.2 Inland Water Environmental Quality
5.2.1 Wetlands
Table 5 identifies the management objectives for all the three categories of geomorphic wetland.
Table 5: Wetland Management Categories and Objectives Management
Category General
Description Management Objectives Conservation Wetlands support a
high level of ecological attributes and functions
Highest priority wetlands. Objective is preservation of wetland attributes and functions through various mechanisms including:
reservation in national parks, Crown reserves and state-owned land
protection under Environmental Protection Policies
wetland covenanting by landowners.
These are the most valuable wetlands and the Commission will oppose any activity that may lead to the further loss or degradation. No development.
Resource
Enhancement Wetlands which may have been partially modified but still support substantial
ecological attributes and functions
Priority wetlands. Ultimate objective is for management, restoration and protection towards improving their conservation value. These wetlands have the potential to be restored to conservation category. This can be achieved by restoring wetland structure, function and biodiversity. Protection is recommended through a number of mechanisms.
Multiple Use Wetlands with few important ecological attributes and functions remaining
Use, development and management should be considered in the context of ecologically sustainable development and best management practice catchment planning through land care. Should be considered in strategic planning.
Source: Water and River Commission 2001
5.2.1.1 Swan Coastal Plain Geomorphic Wetland Mapping
Figure 9 presents the current Swan Coastal Plain geomorphic wetland mapping for the site and the buffer requirements for the Conservation Category and Resource Enhancement wetlands.
Conservation Category Wetland
The mapped Conservation Category wetland (UFI15259) is located within the Bennett Brook and foreshore (Figure A).
Figure A: Bennett Brook Foreshore Setback
Figure A illustrates that the Bennett Brook watercourse and the Conservation Category wetland (UFI15259) are not correctly aligned. The LSP has accommodated over a 100 m buffer from the Bennett Creek and 50 m buffer from the mapped Conservation Category wetland boundary (Figure A and Figure 9).
Resource Enhancement Wetland
Located within Lot 41 Marshall Road the Resource Enhancement wetland (UFI14129) consists of a stand of Melaleuca sp. with a mixed exotic Closed Grassland consisting of pasture species underneath (Plate B).
The Resource Enhancement wetland is currently utilised for agricultural purposes (e.g.
sheep paddock).
Plate B: Existing Resource Enhancement Wetland Environment
6.0 PEOPLE-THEMED FACTORS
6.1 Amenity
6.1.1 Noise
Figure 2 identifies that land holdings abutting Reid Highway, to the south of the site.
Additionally, the Reid Highway and Lord Street, which lie adjacent to the site in the south and east, respectively, are both reserved under the MRS as “Primary Regional Roads”.
An Acoustic Assessment was undertaken in 2015 by Herring Storer Acoustics for the site to determine the extent to which potential noise impacts received from road traffic would impact future residential development (Appendix 4).
Herring Storer Acoustics (2015) determined that without any noise amelioration, noise received at the majority of future residences located adjacent to the roads would exceed the noise targets, as set out in SPP 5.4: Road and Rail Transport Noise and Freight Considerations in Land Use Planning.
Herring Storer Acoustics (2015) recommended the following measures to address the identified road traffic noise:
implementation of Quiet House Design along Marshall Road
construction of a 1.8–2.0 metre high barrier and Quiet House Design along Lord Street
construction of a 2.0 metre high barrier and Quiet House Design along the Reid Highway
notification on Titles for those residences that receive a noise level that exceeds noise targets.
6.1.2 Odour
A poultry farm is located approximately 530 m north of the site on Lot 60 Cheltenham Street, Bennett Springs.
Figure 10 shows the extent of the 500 m buffer in relation to the site and demonstrates that the site is not located within the poultry farm buffer. This buffer distance is consistent with the EPA’s draft separation distances between industrial and sensitive land uses (EPA 2015).
It is also noted there is an approved subdivision approximately 520 m east of the poultry farm.
6.2 Heritage
6.2.1 Aboriginal Heritage
A search of the Department of Aboriginal Affairs (DAA) Aboriginal Heritage Inquiry System database was undertaken on 20 July 2015 and identified that the following three Registered Sites intersect or overlay the site whilst Other Heritage Place (West Swan Isolated Artefacts; Site ID: 22643) lies within the site (Figure 11; Appendix 5):
Bennett Brook: in toto (Site ID: 3692)
Marshalls Paddock (Site ID: 3744)
Bennett Brook: Camp Area (Site ID: 3840).
An ethnographic consultant has been engaged to undertake a section 18 application and engagement with the Traditional Owners in accordance with the Aboriginal Heritage Act 1971.
6.2.2 European Heritage
A search of the Heritage Council’s inHerit database and the City of Swan’s Municipal Inventory was undertaken on 20 July 2015 and no matches were recorded for the site.
6.3 Human Health
6.3.1 Potential Contamination
A search of the DER’s Contaminated Sites database was undertaken on 20 July 2015 and no recorded contaminated site was identified for the LSP site.
The site has been historically used for agricultural practices and contains aged infrastructure associated with agricultural land uses. Potentially, this infrastructure may have been made from materials containing asbestos.
After the removal of the existing infrastructure from the site, the areas subject to demolition works will be remediated in accordance with the Contaminated Sites Act 2003 to be suitable for residential land uses.
6.4 Bushfire Risk
A Bushfire Management Plan has been prepared by Strategen to manage the potential bushfire risk posed by vegetation within, and adjacent, to the site through the implementation of a raft of mitigation measures.
The vegetation assessed by Strategen (2015) primarily consists of the stand of Melaleuca sp. with a mixed exotic Closed Grassland extent associated with the Resource Enhancement wetland within the site and the four vegetation units that comprise the Bennett Brook foreshore environment adjacent to the site. The vegetation associated with the mapped extent of the Resource Enhancement wetland and the foreshore vegetation of Bennett Brook present permanent bushfire hazard considerations.
Strategen (2015) classified the bushfire hazard presented by these vegetation extents in accordance with Guidelines for Planning for Bushfire Prone Areas (Department of Planning and WAPC 2015a), SPP 3.7: Planning in Bushfire Prone Areas (Department of Planning and WAPC 2015b) and Australian Standard 3959:2009: Construction of Buildings in Bushfire-prone Areas (Standards Australia 2009). Bushfire hazard ratings, based on the vegetation classifications, were used to inform the Bushfire Attack Level assessment and subsequently define the necessary responses for future development within the LSP.
Strategen (2015) concluded that the LSP is expected to meet the stated objectives of SPP 3.7: Planning in Bushfire Prone Areas (Department of Planning and WAPC 2015b).
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7.0 POTENTIAL ENVIRONMENTAL IMPACTS AND MANAGEMENT MEASURES
7.1 Introduction
This section details potential environmental impacts and proposes management measures to address the identified impact. Each environmental factor is addressed in the same format, using a series of four sub-headings as follows.
Environmental Objective – States the EPA’s objective for the identified environmental factor in accordance with Environmental Assessment Guideline No. 8: Environmental factors and objectives (EPA 2013).
Applicable Guidelines, Standards and Policies – The environmental factor is placed in context of the appropriate policy framework.
Potential Impacts – Describes the identified potential environmental impacts that might arise from the proposed development. This may take the form of impacts of the development on the environment, or constraints the environment might represent to successfully realise the project.
Management Response – Details proposed environmental management responses to address the potential impacts.
7.2 Land-themed Factors
7.2.1 Flora and Vegetation
7.2.1.1 Environmental Objective
To maintain representation, diversity, viability, and ecological function at the species, population and community level.
7.2.1.2 Applicable Guidelines, Standards and Policies
Environment Protection and Biodiversity Conservation Act 1999
Wildlife Conservation Act 1950
Position Statement No. 2: Environmental Protection of Native Vegetation in Western Australia (EPA 2000).
7.2.1.3 Potential Impacts
The site’s historical use for agriculture has completely degraded the vegetation and reduced the native vegetation cover to minimal areas containing scattered trees with no native understorey. Consequently, it is anticipated that the LSP would have very little impact on native vegetation.
7.2.1.4 Management Response
The following management measures have been developed and incorporated into the LSP to reduce the likelihood of impacts to vegetation and flora:
portion of Conservation Category wetland and its associated buffer within the site, and the Resource Enhancement wetland and its associated buffer to be managed in accordance with a Foreshore Management Plan and Wetland Management Plan, respectively
placement of POS on Lot 44 to retain as many trees as possible
planting trees / vegetation as part of the development’s landscaping works.
7.2.2 Terrestrial Environmental Quality – Acid Sulfate Soils
7.2.2.1 Environmental Objective
To maintain the quality of land and soils so that the environment values, both ecological and social, are protected.
7.2.2.2 Applicable Guidelines, Standards and Policies
Assessment Levels for Soil, Sediment and Water (Department of Environment and Conservation [DEC] 2010)
Acid Sulfate Soils Guideline Series. Treatment and Management of Soils and Water in Acid Sulfate Soil Landscapes (DEC 2011)
Identification and Investigation of Acid Sulfate Soils and Acidic Landscapes (DEC 2013).
7.2.2.3 Potential Impacts
ASS soils are stable when left undisturbed, but when they are exposed to air, during excavation or dewatering, this can set off a reaction resulting in acidity (sulfuric acid) being produced.
The potential impacts relate to the potential for oxidation of excavated or in-situ ASS generating acidic conditions, and possibly releasing metals into groundwater and surrounding freshwater environment of Bennett Brook.
7.2.2.4 Management Response
The final fill levels and engineering service excavation requirements will determine if an ASS and Dewatering Management Plan (ASSDMP) is required to be prepared prior to subdivision.
If required, the ASSDMP will outline the soil management measures, the groundwater and dewatering effluent monitoring measures and the contingency management measures required to minimise any environmental impacts to the satisfaction of the DER.
7.3 Water-themed Factors
7.3.1 Hydrological Processes
7.3.1.1 Environmental Objective
To maintain the hydrological regimes of groundwater and surface water so that existing and potential uses, including ecosystem maintenance, are protected.
7.3.1.2 Applicable Guidelines, Standards and Policies
Better Urban Water Management (WAPC 2008).
7.3.1.3 Potential Impacts
The identified key potential impacts include:
change in hydrological regime as a result of changed landforms (from earthworks), which may alter natural flows and levels
discharge of stormwater may affect the quality of groundwater and surface water.
7.3.1.4 Management Response
Stormwater and drainage generated within the site will be managed in accordance with the provisions of the WAPC’s Better Urban Water Management framework, which establishes the requirement for a LWMS to be prepared to support a LSP.
A LWMS (RPS 2016) has been prepared for the site, to manage stormwater drainage and potential impacts to surface water and groundwater, in accordance with the West Swan “West” DWMS (TME 2011) and WAPC (2008).
Urban Water Management Plan(s) are required to be completed at subdivision stage to the satisfaction of the CoS, on advice from the DoW.
7.3.2 Inland Waters Environmental Quality
7.3.2.1 Environmental Objective
To maintain the quality of groundwater and surface water, sediment and biota so that the environmental values, both ecological and social, are protected.
7.3.2.2 Applicable Guidelines, Standards and Policies
Bulletin 686: A Guide to Wetland Management in the Perth and Near Perth Swan Coastal Plain Area (EPA 1993).
Position Statement No 4: Environmental Protection of Wetlands (EPA 2004a).
Draft Guideline for the Determination of Wetland Buffer Requirements (WAPC 2005).
7.3.2.3 Potential Impact
The identified key potential impacts to Bennett Brook include:
altered hydrological regimes.
7.3.2.4 Management Response
Foreshore Management Plan for Bennett Brook and its associated buffer (adjacent to the LSP) to be prepared at subdivision stage.
Wetland Management Plan for the Resource Enhancement wetland and its associated buffer to be prepared at subdivision stageby the landowner(s).
7.4 People-themed Factors
7.4.1 Noise
7.4.1.1 Environmental Objective
To ensure that impacts to amenity are reduced as low as reasonably practicable.
7.4.1.2 Applicable Guidelines, Standards and Policies
Environmental Protection (Noise) Regulations 1997
Environmental Assessment Guideline 13: Consideration of Environmental Impacts from Noise (EPA 2014)
SPP 5.4: Road and Rail Transport Noise and Freight Considerations in Land Use Planning (WAPC 2009).
7.4.1.3 Potential Impact
Noise associated with road traffic has the potential to impact the amenity of future residential development within the site.
7.4.1.4 Management Response
In accordance with the findings of Herring Storer Acoustics (2015), the following noise mitigation measures will be incorporated into the subdivision design and / or the constructed development to address the identified road traffic noise:
implementation of Quiet House Design along Marshall Road
construction of a 1.8–2.0 metre high barrier and Quiet House Design along Lord Street
construction of a 2.0 metre high barrier and Quiet House Design along the Reid Highway
notification on Titles for those residences that receive a noise level that exceeds noise targets.
7.4.2 Heritage
7.4.2.1 Environmental Objective
To ensure that historical and cultural associations are not adversely affected.
7.4.2.2 Applicable Guidelines, Standards and Policies
Aboriginal Heritage Act 1972
Guidance Statement No. 41: Assessment of Aboriginal Heritage (EPA 2004b).
7.4.2.3 Potential Impact
The potential impacts of the proposed development on Aboriginal Heritage sites are related primarily to direct disturbance of sites including excavation / construction activities unearthing and / or damaging artefacts or other items of cultural Aboriginal significance.
7.4.2.4 Management Response
Apply for approval to disturb the Aboriginal archaeological site under Section 18 of the Aboriginal Heritage Act 1972.
Be vigilant during earthworks and stop work immediately should any items be discovered.
7.4.3 Human Health
7.4.3.1 Environmental Objective
To ensure that human health is not adversely affected.
7.4.3.2 Applicable Guidelines, Standards and Policies
Contaminated Sites Act 2003
DER Contaminated Sites Guidelines series.
7.4.3.3 Potential Impact
The site has been historically used for agricultural practices and contains aged infrastructure associated with agricultural land uses. Potentially, this infrastructure may have been made from materials containing asbestos.
7.4.3.4 Management Response
After the removal of the existing infrastructure from the site, the areas subject to demolition works will be remediated in accordance with the Contaminated Sites Act 2003 to be suitable for residential land uses.
7.4.4 Bushfire Risk
7.4.4.1 Objectives
To reduce the risk of bushfire to people, property and infrastructure.
7.4.4.2 Applicable Guidelines, Standards and Policies
Australian Standard AS 3959:2009, Construction of Buildings in Bushfire-prone Areas (Standards Australia 2009)
Guidelines for Planning in Bushfire Prone Areas (Department of Planning and WAPC 2015a)
SPP 3.7: Planning in Bushfire Prone Areas (Department of Planning and WAPC 2015b).
7.4.4.3 Potential Impacts
The implementation of subdivisions and development within the site will result in an increased risk to people, property and infrastructure being impacted by potential bushfires in the Bennett Brook foreshore environments and the Resource Enhancement wetland.
7.4.4.4 Management Response
A Bushfire Management Plan (Strategen 2015), inclusive of bushfire hazard assessment, has been prepared. The management measures and works program within the approved Bushfire Management Plan will be implemented during construction.