Project Hurunui Wind Construction and Project Overview

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Project Hurunui Wind Construction Effects and Management Report E. The extent and fill depths for each site will also be confirmed on the ground with landowners/relevant stakeholders prior to construction and included within the Supplementary Environmental Management Plan. It is expected that the following typical measures would be incorporated into the design and construction of the fill sites, as appropriate: • Strip topsoil and soft materials from the ground surface and stockpile. • Bench slopes as required to key in fill. • Install subsoil drainage in the base of gullies with branches to areas of observed seepage • Prepare surface drains within and on the periphery of the site to prevent erosion and mitigate run-off as applicable. • Compact the fill adequately to ensure sufficient strength for stability and minimise settlements. • Adopt an appropriate fill profile for stability by considering the nature of the material and proposed fill height. The outer profile of the fill may vary between 3H:1V to 2H:1V. • Where appropriate, surface cut off drains will be formed around the head of fill sites. Such drains are to have controlled outlets in stable locations clear of the fill area and any areas of hillside instability. • Shape final surface of the fill to blend into the landform. • The surface of the fill will generally be covered in topsoil (which has been previously removed and stockpiled) and vegetated with suitable and appropriate ground cover. The plant species shall be consistent with the species in the immediate vicinity of the exposed area, replacing “like with like”. Generally the site is covered in pasture and this is expected to be the predominant ground cover, with some areas of silver tussock. • Sediment control measures, as discussed in Section 3.3, will be installed to manage sediment run-off during construction and until ground cover is established. Examples of fill sites at other Meridian Wind Farm Projects are provided in Appendix F. These are described as follows: • Photograph F16 illustrates a fill site being prepared with benched slopes at Project White Hill. • Photographs F17 and F18 show fill sites being prepared at Project West Wind. • Photograph F19 shows a disposal fill site at Project West Wind under rehabilitation. 5C-1604.02 February 2011 30
Project Hurunui Wind Construction Effects and Management Report • Photograph F20 illustrates a rehabilitated fill site at Project Te Apiti. 3.2.6 Concrete Works Two foundation types may be used within the site depending on bedrock competency and the depth of any overburden. These are a standard gravity pad or a rock anchor solution. Specific foundation details will be developed during the detailed design in conjunction with detailed geotechnical investigations and site specific testing. Indicative reinforced concrete foundation concepts are illustrated in Drawing Sheet 80 in Appendix A (Appendix A.5 Typical Turbine Platform & External Turbine Transformer Details). The pessimistic volume of reinforced concrete associated with the gravity pad and rock anchor solution, respectively, is estimated to be approximately 400m 3 and 120m 3 per foundation. In order to provide an indication of resource inputs to the foundation construction a conservative scenario based on the use of standard gravity pad foundations at all sites has been adopted. Table 10 below summarises the approximate total volume of concrete and the total number of concrete truck trips required based on this foundation type. We have assumed that concrete trucks will only be 75% full due to the gradients present (ie 4.5m 3 per truck). Volume of Each Pad (m 3 ) Total Volume of 33 Pads (m 3 ) (Including site concrete) No. of Trucks per pad Total No. of Trucks 400 13,200 94-96 3,200 Table 10: Concrete Pad Foundation Volumes and Truck Trips At these production volumes it is envisaged the contractor will establish an on-site concrete batching plant to minimise the number of truck movements on the public road network and increase efficiency, i.e. fewer larger trucks delivering cement and aggregate. Such an approach on Project Te Apiti, White Hill and West Wind has demonstrated these benefits. Employing concrete batching plants is discussed in more detail in Section 7. We have assumed concrete aggregates will be sourced off site. Potential sources of concrete aggregates have been identified from quarries at local rivers such as the Hurunui to the north/northwest and the Waipara to the south. Subject to approval from the Hurunui District Council, water supply for the batching plant may be sourced from the mains water supply network located throughout the site. Otherwise water will be delivered to site by tankers(Refer to section 3.2.17 for further information). It is estimated that 72,000 litres (72m 3 ) of water will be required for each 400m 3 foundation. Based on 33 gravity pad foundations, Table 11 indicates the average demand on resources during turbine foundation construction. 5C-1604.02 February 2011 31
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Project Hurunui Wind Construction and Project Overview

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