Project Hurunui Wind Construction and Project Overview

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Project Hurunui Wind Construction Effects and Management Report • Requires no stream crossings thereby reducing environmental impacts • Provides access to the site from a local road rather than a State Highway 3 Core Site Construction Works 3.1 Overview and Site Description 3.1.1 General Approach The overall access road design philosophy has been to follow existing tracks and tops of ridges wherever possible. This minimises the volume of excavation (and hence land disturbance), improves geotechnical conditions, reduces the risk of erosion (due to these being the flatter areas) and generally avoids areas such as gullies and undisturbed watercourses. As discussed in Section 2.1 above the width of the core site access roads are largely governed by the crane required to erect the wind turbine components, together with the provision of safe and efficient utilisation for construction traffic. Within the core site two access road widths have been assumed: • 7m wide trafficable width (formation width of 8.5m) for the main access road from the public road network to the core site. • 6m wide trafficable width for core site access roads. 3.2 Land Disturbance The main sources of land disturbance will arise from: • Forming access roads and working platform areas at turbine sites. • Disposing excess excavated material at suitable sites identified within the project area. The identification of spoil fill areas is part of the Supplementary Environmental Management Plan (SEMP) process (Refer Environmental Management Plan in Appendix E). • Establishing borrow areas at suitable locations to be identified within the project area to extract aggregates for road construction. • Forming turbine component lay down areas at strategic locations. • Forming platforms for site offices and a workshop. • Forming a platform for a concrete batching plant. • Forming a platform for the substation. • Laying underground cables, or the construction of overhead lines, between the turbine sites and substations. 5C-1604.02 February 2011 16
Project Hurunui Wind Construction Effects and Management Report • Overhead transmission from the substations to the external transmission network. • Constructing foundations for each turbine. • Constructing wind monitoring tower foundations. The indicative access road and site layout are shown in the drawings in Appendix A (Appendix A.2 – Access Road Plans & Cross Sections). Drawing Sheets 6 and 7 highlight indicative gradients along each of the access road alignments, while Drawing Sheets 8 and 9 show the approximate cross slopes along the roads and cross reference those to typical cross sections on Drawing Sheet 10. Access road plans are also provided from MXRoad which illustrate the construction footprint and location of road cuts and fills. These are shown on Drawing Sheets 11 to 14 with corresponding extreme cross sections shown on Drawing Sheets 15 to 19. Drawing Sheets 11 to 14 also identify the location of the access roads and turbines platforms in relation to areas of higher ecological value identified in the Ecological Values and Assessment of Effects report prepared by Boffa Miskell. These drawing sheets illustrate how the road alignments and turbine platforms have been designed to avoid these areas in all cases apart from the following areas: • The beginning of Road E prior to the junction between Turbines E1 and E2. Although Road E has been designed to avoid the majority of an area identified as having higher ecological value, it passes through the area’s eastern side as shown on Drawing Sheet 12. Avoiding the area completely by aligning Road E either further to the east or to the west would involve a greater impact by significantly increasing road cuts and earthwork volumes. • The northern corner of the platform for Turbine A11 affects a small section identified as having higher ecological value. The area affected may be reduced at detailed design stage when refinements to the turbine platform will be investigated. • One small section on Road A between Turbines A7 and A6. The access road alignments and turbine positions as indicated are based on available topographical and preliminary geotechnical information. During the detailed survey/investigation and design stage, access road alignments and turbine positions will be refined to optimise the design and suit terrain/geotechnical conditions. In this regard, it is recognised that it may be necessary to reposition turbines within a 100m radius placement area. The same 100m placement envelope will also apply to access roads. This approach has been approved by the Councils and Environment Court for Project West Wind and Central Wind. Similarly this approach has been adopted and approved by Council for Project Mill Creek, currently awaiting an Environment Court Hearing decision. 3.2.1 Detailed Description of Core Site Access Roads Project Hurunui Wind is sited in reasonably complex terrain and therefore turbines typically need to be placed on the ridge tops clear of localised topographic obstructions to minimise turbulence and capture higher mean wind speeds. While the total land holding area of this project is approximately 34km 2 , only a small proportion of this is realistically available for turbine placement due to topographic constraints. 5C-1604.02 February 2011 17
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Project Hurunui Wind Construction and Project Overview

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