Main Roads Western Australia Report for Great Northern Highway
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Main Roads Western Australia Report for Great Northern Highway Rehabilitation Project: Colourstone, Erskine and Ellendale Sections Environmental Impact Assessment and Environmental Management Plan March 2007 Contents Executive Summary 1 1. Introduction 4 1.1 Project Description 4 1.2 Scope of Report 4 2. Existing Environment 7 2.1 Study Area 7 2.2 Climate 7 2.3 Geology, Soils and Topography 8 2.4 Hydrology 9 2.5 Reserves and Conservation Areas 10 2.6 Environmentally Sensitive Areas 10 2.7 Vegetation 10 2.8 Flora 11 2.9 Fauna 14 2.10 Acid Sulfate Soils 21 2.11 Contaminated Sites 21 2.12 Heritage 21 2.13 Surrounding Land Use 22 2.14 Noise and Vibration 23 2.15 Ambient Air Quality 23 2.16 Review of Shire Information 23 3. Results of Field Investigations 24 3.1 Methodology 24 3.2 Hydrology and Drainage 24 3.3 Vegetation 25 3.4 Fauna 30 4. Clearing of Native Vegetation 32 4.1 Assessment against the Clearing Principles 32 5. Management of Environmental Impacts 35 5.1 Vegetation 35 5.2 Risks to Fauna 36 61/18564/63923 Great Northern Highway Rehabilitation Project: Colourstone, Erskine and Ellendale Sections i Environmental Impact Assessment and Environmental Management Plan 5.3 Aboriginal Heritage 37 5.4 Visual Amenity 37 5.5 Construction Issues 38 5.6 Water and Drainage 39 5.7 Rehabilitation 40 5.8 Environmental Management 40 6. Requirement for Referral 41 6.1 Commonwealth Government 41 6.2 Western Australian Government 41 7. Conclusions 42 8. Report Limitations 44 9. References 45 Table Index Table 1 Conservation codes and descriptions for the DEC’s Declared Rare and Priority flora species. 12 Table 2 Significant flora present within the Colourstone, Erskine and Ellendale Sections of the Great Northern Highway as recorded by the DEC’s Rare Flora Databases. 13 Table 3 Threatened fauna occurring, or likely to occur, in the three study sections as indicated by the EPBC Act Protected Matters Search Tool and the DEC’s Rare Fauna Database 15 Table 4 Vegetation types present along the Colourstone, Erskine and Ellendale Sections of the Great Northern Highway. 26 Table 5 Vegetation extent and status. 28 Table 6 Assessment against the Ten Clearing Principles. 33 Table 7 WA Museum Records (21•12•2006) • Colourstone, Erskine and Ellendale Sections of the Great Northern Highway 55 Table 8 Environmental Protection And Biodiversity Conservation Act 1999 Categories 59 Table 9 Western Australian Wildlife Conservation Act 1950 Codes 59 61/18564/63923 Great Northern Highway Rehabilitation Project: Colourstone, Erskine and Ellendale Sections ii Environmental Impact Assessment and Environmental Management Plan Table 10 Western Australian Department of Environment and Conservation Priority Fauna Codes (Species not listed under the Wildlife Conservation Act 1950, but for which there is some concern). 60 Table 11 Flora list for the Colourstone, Erskine and Ellendale Sections of the Great Northern Highway Rehabilitation Project. 63 Table 12 Fauna list for the Colourstone, Erskine and Ellendale Sections of the Great Northern Highway Rehabilitation Project. 70 Figure Index Figure 1 Locality map of the Colourstone, Erskine and Ellendale sections of the Great Northern Highway. 48 Figure 2 Declared Rare and Priority Flora species within the vicinity of the Colourstone section of the Great Northern Highway. 49 Figure 3 Declared Rare and Priority Flora species within the vicinity of the Erskine section of the Great Northern Highway. 50 Figure 4 Declared Rare and Priority Flora species within the vicinity of the Ellendale section of the Great Northern Highway. 51 Figure 5 Aboriginal heritage sites within the vicinity of the Colourstone Section of the Great Northern Highway. 52 Figure 6 Aboriginal heritage sites within the vicinity of the Erskine Section of the Great Northern Highway. 53 Plate Index Plate 1 Juvenile Boab Tree (~2 • 3m) 75 Plate 1 Young Boab tree (~5 – 6m) 76 Plate 2 Medium sized, multi•stemmed Boab tree (~5 • 6m) 77 Plate 3 Medium sized Boab tree (~7 • 10m) 78 Plate 5 Large, multi•stemmed Boab tree (~15 m) 79 Appendices A Figures B Fauna 61/18564/63923 Great Northern Highway Rehabilitation Project: Colourstone, Erskine and Ellendale Sections iii Environmental Impact Assessment and Environmental Management Plan C Heritage D Field Survey E Boab Trees 61/18564/63923 Great Northern Highway Rehabilitation Project: Colourstone, Erskine and Ellendale Sections iv Environmental Impact Assessment and Environmental Management Plan Executive Summary An Environmental Impact Assessment (EIA) and Environmental Management Plan (EMP) was prepared by GHD Pty Ltd on Behalf of Main Roads Western Australia for three sections of the Great Northern Highway Rehabilitation Project. The three sections investigated were: » Colourstone Section: SLK 2237.1 – 2250.1 » Erskine Section: SLK 2370.6 – 2381.8 » Ellendale Section: SLK 2415.3 – 2435.4 The following is a summary of the environmental aspects relevant to the project: » No reserves or conservation areas are located within or near the vicinity of the study areas; » A floodplain area is located within the Ellendale Section, and is associated with Mount Wynne Creek, which transects this section at approximately SLK 2431.0. Tributaries of the Little Logue River cross the Colourstone Section. These drainage lines and floodplains are ephemeral features and flow following heavy summer rainfall events. » The Canning•Kimberley Groundwater Area covers the entire Kimberley sub•region. Where dewatering, obstruction of groundwater or modification of stream banks is required for roadworks and bridge construction, Main Roads will need to compete the relevant application forms available from the Department of Water. » Construction works are likely to temporarily increase runoff and sedimentation. With appropriate management actions in place, surface hydrology and drainage is not considered likely to be adversely impacted by this project; » No Environmentally Sensitive Areas are located within or near the vicinity of the study areas; » The Department of Indigenous Affairs (DIA) Aboriginal Heritage Inquiry System indicates that the following known Aboriginal heritage sites are located within two of the three study areas; o Colourstone Section: Nilli Bubbaca Well (Camp, Water Source); and o Erskine Section: Erskine Ranges (Artefacts / Scatter, Rockshelter). » A field survey conducted in October 2006 delineated the following broad vegetation types for each of the study areas: o Colourstone Section: Pindan Woodland o Erskine Section: Hummock Grass Steppe o Ellendale Section: Pindan Shrubland » The condition of vegetation within the study areas was generally homogenous and was assessed to range from Pristine•Excellent to Very Good. Recently burnt 61/18564/63923 Great Northern Highway Rehabilitation Project: Colourstone, Erskine and Ellendale Sections 1 Environmental Impact Assessment and Environmental Management Plan vegetation present at a number of survey locations sites made rating the condition of the vegetation difficult; » Each study area is wholly surrounded by continuous vegetation, with major disturbances being from fire or livestock grazing; » Vegetation extent is considered to be intact with 100% of the pre•European extent of vegetation remaining. The vegetation is poorly conserved within conservation areas, but the considerable extent of the vegetation and the remote nature of the study areas limit the threats to these vegetation types; » No Threatened Ecological Communities were recorded within the study areas; » A total of 117 species from 36 families were recorded from the study areas. Vegetation within the study areas is considered moderately diverse; » The flora survey was conducted outside the peak flowering season for flora in the Kimberley region. During this time annual plant species are typically absent, grass species senescent, and most perennial flora species have ceased flowering, reducing the capability for identification purposes and limiting the effectiveness of the flora survey; » No Declared Rare or Priority Flora species were recorded within the study areas, however; there are culturally significant flora species (Adansonia gregorii, Boab) within each of the surveyed areas and individual plants should not be disturbed where possible. » No threatened fauna species were recorded from the study areas. Field surveys did however observe evidence to suggest the presence of the Schedule 1 fauna species Petrogale lateralis (Black•footed Rock Wallaby (West Kimberley Race)) within the Erskine Section. Faecal matter observed within the rocky outcrops of the Erskine Ranges was noted to be distinctively different from Macropus spp. The Erskine Ranges is one of three known locations for populations of this wallaby. The project will not directly impact this species, however; care should be taken around the Erskine Ranges as it is likely that the wallaby would cross the highway at this point during foraging or when accessing a water point south of the road alignment. Any habitat disturbance should also be minimised within this section; » Fauna habitat and linkages will not be significantly disturbed or disrupted by the works planned for these sections. It is not considered that the extraction of material for the highway upgrade will significantly alter the fauna habitat of the region. It can be considered that a disturbance will occur on a local scale, which is likely to impact on individual animals, rather than a population; » Noise, dust and vibration from construction works are not likely to cause an impact, however