Brookton¢â€¬Highway¢â€¬Upgrade (221.6¢â€¬¢â‚¬â€œ226.0¢â€¬SLK) Brookton¢â€¬Highway¢â€¬Upgrade¢â€¬(219¢­226¢â€¬SLK)

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  • June 2005

    Main Roads Wheatbelt South Region

    Brookton Highway Upgrade (221.6 –226.0 SLK)

    Environmental Impact Assessment and Environmental Management Plan

  • Brookton Highway Upgrade (219.6-226.0 SLK) Environmental Impact Assessment and Environmental Management Plan



    Executive Summary 1

    1. Introduction 4

    2. Project Description and Justification 6

    3. Environmental Impacts and Management 9 3.1 Natural Environment 9

    3.2 Social Environment 19

    3.3 Pre-construction Phase 23

    3.4 Construction Phase 23

    4. Consultation 27 4.1 Adjacent Landowners 27

    4.2 Environmental Protection Authority 27

    4.3 Department of Conservation and Land Management 27

    5. Environmental Approvals 29 5.1 Commonwealth Government 29

    5.2 Western Australian Government 29

    6. Environmental Compliance and Monitoring 30

    7. References 31

    Table Index Table 1 Brookton Highway Widening and Realignment Project Key

    Characteristics Table 6

    Table 2 Vegetation Communities intersected by the Brookton Highway- Corrigin Upgrade (After Beard, 1980). 11

    Table 3 Vegetation Type, Extent and Conservation Status 13

    Figure Index Figure 1 Project Locality Plan

    Figure 2 Reserve Boundaries

    Figure 3 Project Design and Aerial

    Figure 4 Gorge Rock Re-alignment Option

  • Brookton Highway Upgrade (219.6-226.0 SLK) Environmental Impact Assessment and Environmental Management Plan


    Appendices A Project Environmental Aspects Table

    B Environmental Management Responsibilities and Actions Table (Environmental Management Plan)

    C Bush Forever (2000) Vegetation Condition Rating of Site Vegetation

    D Photographs of the Project Area

    E Appendix E F List of Declared Rare and Priority Flora Potentially Occuring in the Project


  • 1Brookton Highway Upgrade (219-226 SLK) Environmental Impact Assessment and Environmental Management Plan


    Executive Summary

    GHD Pty Ltd (GHD) was commissioned by Main Roads WA Wheatbelt South Region (Main Roads) to prepare an Environmental Impact Assessment and Environmental Management Plan (EIA & EMP) for the proposed upgrade of a seven kilometre section of the Brookton Highway (221.6 – 226.0 SLK) located 17 km east of Corrigin.

    The project under assessment was included within the Brookton Highway (Corrigin to Kalgarin) project which was formally referred to the WA Environmental Protection Authority (EPA) by Main Roads in May 2003 (EPA reference CRN 188905). The EPA set a level of assessment at the level of Not Assessed – Public Advice Given. Two appeals were raised against the proposed level of assessment by members of the community. Due to the timing of the appeals resolution process and Main Roads road construction timing the proposal was subsequently withdrawn from the assessment process by Main Roads.

    This EIA & EMP has been prepared to:

    ª Describe the significant aspects of the existing project environment;

    ª Detail the primary environmental impacts of the proposed roadworks, and

    ª Provide actions to manage and minimise the identified environmental impacts.

    The proposed roadworks consist of widening 3.45 km of the existing road on its present alignment and a 0.95 km re-alignment through Water Reserve 9 425 and Recreation and Hall Reserve 18 318. The land requirement from Reserves 9 425 and 18 318 is 4.7 ha from a total of 91.7 ha. No land will be required or impacted from the adjacent “A” Class Gorge Rock Nature Reserve (Reserve 16 714).

    Main Roads considered an alternative alignment to the proposed works to minimise impacts on Reserves 18 318 and 9 425. This alternative route south of the reserve areas was considered unacceptable for the following reasons:

    ª The alternative re-alignment would cross a watercourse located to the south twice. This watercourse is identified by DoE as an Environmentally Sensitive Area and would require the construction of two floodways at the crossing point;

    ª The alternative option would result in significant land acquisition and severance impacts on private property. Land owners are expected not to agree to the land acquisition. Land acquisition and compensation costs are are expected in the vicinity of $200 000;

    ª The alternative alignment would require 3.7 km of additional road to be constructed; and

    ª Estimated additional costs of $470 000 for roadworks and intersections, and $400 00 for floodways.

    Main Roads also considered the option of widening the existing highway on its current alignment rather than a re-alignment. This option was considered unacceptable due to the road’s poor horizontal geometry (i.e. sharp curve), which would not improve road safety at the site.

    The vegetation of the project area was assessed during the Spring of 2005 conforming to methodologies stipulated in the Bush Forever’s Vegetation Condition Rating System (Department of Environmental Protection 2000). It is anticipated that some 2.43 ha of native vegetation will be cleared to provide for the

  • 2Brookton Highway Upgrade (219-226 SLK) Environmental Impact Assessment and Environmental Management Plan


    proposed roadworks. Of the expected clearing impact approximately 34% (0.82 ha) is of vegetation in good condition (Bush Forever Condition 3), 36 % (0.88 ha) is of moderate condition (Bush Forever Condition 4) while the remaining 30% (0.73 ha) of vegetation could be described as degraded to severely degraded (cleared) (Bush Forever Condition 5-6). The remainder of the roadworks footprint is 0.6 ha which is currently cleared land.

    The vegetation of the project area can be considered as four vegetation associations based on the vegetation decriptions of Shepherd et al (2002). All four of these vegetation associations are considered to be poorly regionally represented, being below the 30% threshold level set by the Environmental Protection Authority (EPA, 2000).

    Main Roads propose to widen the existing 20m wide road reserve to 60m where it traverses private property, with the widened reserve being revegated with endemic native vegetation. It is expected that approximately 6 ha of widened road reserve and redundant sections of Brookton Highway and the Bullaring Gorge Rock Road will be available for revegetation at the completion of roadworks.

    Based on flora surveys in 2000 and 2004 it is expected that five Priority 4 Metallic Flowered Eremophila (Eremophila veneta) plants and two Priority 4 Daviesia purpurascens will be taken by the roadworks.

    A search of CALM’s Threatened Ecological Communities database revealed that no such communties are believed to occur within the project area.

    A search of CALM’s Threatened and Priority Fauna species database identified the following species of conservation significance as potentially occuring within the project area: ª Malleefowl (Leipoa ocellata);

    ª Peregrin Falcon (Falco peregrinus);

    ª Australian Bustard (Ardeotis australis); and

    ª White-browed babbler (Pomatastomus temporalis).

    In addition, Carnaby’s Cockatoo (Calyptorhynchus latirostris), although not identified within the CALM database search, has been observed throughout the WA Wheatbelt.

    No mallefowl nest sites were identified within the, or in close proximity to the project area. The works will require the removal of 18 potential Carnaby’s Cockatoo nesting trees and should be timed to avoid the nesting period for this species. After consideration of the fauna habitat to be impacted by roadworks, fauna species mobility and habitat preference, it is considered unlikely that any of the local populations of these threatened or specially protected fauna species will suffer major impacts or their populations be put at threat by the proposed works.

    Dieback disease (Phytophthora cinnamomi) is not considered to be an issue within this project as the project area falls within a rainfall zone of less than 400 mm (Dieback Consultative Council, 2000).

    A variety of weed species were observed during the 2000 and 2004 vegetation surveys of the project area. Most are pasture grasses which have spread from neighbouring paddocks and displaced native

  • 3Brookton Highway Upgrade (219-226 SLK) Environmental Impact Assessment and Environmental Management Plan


    groundcovers. No Declared Weeds listed under the Agriculture and Related Resources Protection Act (1926) were recorded within the site.

    An Aboriginal Heritage Survey of the Brookton Highway between Corrigin and Hyden was conducted for Main Roads in 2000. One previously recorded archaeological site (Site ID 5444) was identified in close proximity to the project area. This site will not be impacted by the proposed works. The ethnographic survey, conducted in consultation with local Aboriginal community group members identified a new site - the Gorge Rock Camp and Hunting Grounds north of the existing highway. This site is not expected to be impacted by roadworks, although may be disturbed by the possible develeopment of a construction camp at the Gorge Rock Hall site. The Ethnographic survey resulted in two conditions being set by the community regarding the Gorge Rock Hall Site and Site S810 ‘Gorge Rock’. These conditions have been included a management measures in the EIA and EMP.

    According to the Heritage Commission of Western Australia, four Heritage listed places were identified within the vicinity of the project, north of the existing