Project Hurunui Wind Construction and Project Overview

Meridian Energy Ltd 

Project Hurunui Wind 

Construction and Project Overview 

Construction Effects & Management Report 

February 2011

Meridian Energy Ltd 

Project Hurunui Wind 

Construction and Project Overview 

Construction Effects & Management Report 

February 2011 

Prepared By 

Len Wiles 

Project Engineer 

Opus International Consultants Limited 

Wellington Office 

Level 9, Majestic Centre, 100 Willis Street 

PO Box 12 003, Wellington 6144, 

New Zealand 

Reviewed By Telephone: +64 4 471 7000 

Gareth McKay Facsimile: +64 4 471 1397 

Project Manager 

Date: 14 Feb 2011 

Reference: 5C-1604.02 

Status: Final 

© Opus International Consultants Limited 2011

Project Hurunui Wind Construction Effects and Management Report 

Contents 

1 Introduction .......................................................................................................................... 1 

2 Access Route, Turbine and Fill Site Selection ................................................................... 4 

2.1 Preliminary Design Criteria ........................................................................................... 4 

2.2 Geotechnical Appraisal ................................................................................................. 7 

2.3 Core Site Access Route & Turbine Site Selection ......................................................... 7 

2.4 Spoil Fill Site Selection ................................................................................................. 9 

2.5 Assessment of Effects & General Consultation ........................................................... 10 

2.6 Implementation Team Review ..................................................................................... 11 

2.7 Access Options ........................................................................................................... 12 

3 Core Site Construction Works .......................................................................................... 16 

3.1 Overview and Site Description .................................................................................... 16 

3.1.1 General Approach ....................................................................................................... 16 

3.2 Land Disturbance ........................................................................................................ 16 

3.2.1 Detailed Description of Core Site Access Roads ......................................................... 17 

3.2.2 Access Road Formation .............................................................................................. 21 

3.2.3 Turbine Platforms ....................................................................................................... 26 

3.2.5 Spoil Fill Sites ............................................................................................................. 29 

3.2.6 Concrete Works .......................................................................................................... 31 

3.2.7 Borrow Areas .............................................................................................................. 32 

3.2.8 Soil Stockpile Areas .................................................................................................... 33 

3.2.9 Site Lay Down Areas .................................................................................................. 34 

3.2.10 Internal Cable Reticulation ................................................................................... 34 

3.2.11 Substation ............................................................................................................ 35 

3.2.12 66 kV Transmission Line Connection ................................................................... 36 

3.2.13 Services Building .................................................................................................. 36 

3.2.14 Meteorological Masts (Wind Monitoring Towers) .................................................. 37 

3.3 Discharges .................................................................................................................. 40 

3.3.1 Erosion, Sediment and Dust Control ........................................................................... 40 

3.3.2 Permanent Stormwater Run-off .................................................................................. 43 

3.3.3 New Culverts at Stream or Gully Crossings in the Core Site ....................................... 44 

3.3.4 Upgrading Existing Culverts Along Motunau Beach Road ........................................... 45 

3.3.5 Culvert Construction Methodology .............................................................................. 45 

4 Minor Shoulder Widening At Motunau Beach Road ........................................................ 45 

4.1 Shoulder Road Widening Opposite Site Entrance ....................................................... 45 

5 Geotechnical Assessment ................................................................................................ 46 

5.1 Geotechnical Appraisal ............................................................................................... 46 

5.2 Geotechnical Risk ....................................................................................................... 46 

5.2.1 Potential Slope Instability ............................................................................................ 46 

5.2.2 Seismic Hazard........................................................................................................... 47 

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6 Other Proposed Activities ................................................................................................. 49 

6.1 Detailed Geotechnical Investigations .......................................................................... 49 

6.2 Controlled Blasting ...................................................................................................... 49 

7 Indicative Construction Methodology, Noise and Lighting............................................. 49 

7.1 Indicative Construction Methodology .......................................................................... 49 

7.2 Construction Noise ..................................................................................................... 51 

7.3 Lighting and Night Works ............................................................................................ 51 

7.4 On Site Project Office ................................................................................................. 52 

7.5 Bulk Fuel Storage Facility ........................................................................................... 52 

7.6 On Site Batching Plant ................................................................................................ 52 

8 Summary and Conclusions ............................................................................................... 53 

Appendix A – 

Appendix B – 

Appendix C – 

Appendix D – 

Appendix E – 

Appendix F – 

Drawing Plans 

A.1 – Overall Site Development Plans 

A.2 – Access Road Plans & Cross Sections 

A.3 – Landowner Boundary Plan 

A.4 – Culvert Location Plans & Typical Details 

A.5 – Typical Turbine Platform & External Turbine Transformer Details 

A.6 – Hydrological Catchment Area Plan 

A.7 – Substation, Underground Cabling & Transmission Line Details 

A.8 – Indicative Site Office & Lay-down Area Plan 

A.9 – Indicative Wind Monitoring Mast Details 

Site Photographs 

Typical Transport Details 

Preliminary Geotechnical Appraisal 

Environmental Management Plan 

Photographs Illustrating Representative Construction Requirements 

and Effects 

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ii


1 Introduction 

Meridian Energy Ltd (Meridian) proposes to develop, build and operate a wind farm 66km 

north of Christchurch as shown on the site location plan on Drawing Sheet 200 in Appendix 

A (Appendix A.1 – Overall Site Development Plans). The proposed core site comprises five 

properties, identified on Drawing Sheet 5 in Appendix A (Appendix A.3 – Landowner 

Boundary Plan), covering approximately 34km 2 and is bounded by: 

• Reeces Road to the southwest. 

• Motunau Beach Road to the northeast. 

• State Highway 1 to the west. 

The core site measures approximately 6km and 5km at its longest and widest points 

respectively. The core site is approximately 30km south of Cheviot and approximately 34km 

north of Amberley. The preferred access to the core site is from Motunau Beach Road off 

State Highway 1. 

The core site is primarily located along two main ridgelines running in a north-east to south 

west direction with some short minor spurs running from the main ridgelines. Both of the 

main ridgelines are typically characterised by sections of eastern facing escarpments. The 

majority of the site is relatively steep undulating countryside interspaced with numerous 

valleys and ridges. The overall site is farm land mainly covered in pasture with some 

occasional tussock at higher altitudes and scrub and shrubland vegetation in some of 

the gullies. The ridgelines lie between 300m and 550m above sea level. Soil depths within 

the area vary typically between 0.5m and 1.0m in thickness, overlying the greywacke 

bedrock. Exposures of naturally occurring bedrock are generally slightly to moderately 

weathered. Road cuts have exposed some areas of moderately to highly weathered 

bedrock. Rock outcrops can be found scattered throughout the site. 

The core site is predominantly covered with pasture, and is used for farming. In addition to 

tracks (typically 2m to 3m in width), and stock fences that have been established by the 

landowners, a water mains network owned by the Hurunui District Council runs through the 

project area. 

The proposed Project Hurunui Wind will consist of thirty three (33) wind turbine generators 

(WTGs) located within the site. The turbines being considered for this site have a 

generation capacity of 2.3MW each and a rotor diameter of 101m. The maximum height of 

each turbine to the tip of a rotor blade when vertical will be approximately 130.5m. 

Each turbine will typically consist of the following components as illustrated in Figure 1 

below: 

• Foundation, typically completely buried. 

• Tapered tubular steel tower. 

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• Nacelle which sits on top of the tower and houses the control gear, generator and 

the main rotor shaft that transmits the rotating energy from the turbine rotor to the 

main gearbox. 

• 3 bladed turbine rotor. 

• External turbine transformer unit at ground level adjacent to the turbine tower (refer 

Drawing Sheet 100 in Appendix A (Appendix A.5 Typical Turbine Platform & 

External Turbine Transformer Details) for details. 

Figure 1 below illustrates the various components of a typical wind turbine generator. 

Figure 1: Typical Wind Turbine Generator (Project West Wind Example) 

Construction of an internal core site road network of approximately 22.2km will be required 

in order to construct and service the WTGs. In addition minor access tracks will be required 

to construct the transmission towers supporting the transmission line between the site 

substation and external 66kV transmission line. Existing farm tracks are to be upgraded 

wherever possible to reduce the net earthworks required to form core site access roads 

thereby minimising the overall impact of earthworks. Upgraded roads, farm tracks and new 

access roads are expected to range in widths from approximately 6m wide, in the majority 

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of cases, to a maximum of 10m at tight bends. In order to reduce construction effects 

access road widths will be kept to a practical minimum. 

At each turbine, a flat platform will be formed to provide a cranage area as well as to 

contain the turbine foundation. Excavated material from these earthworks would be used 

as roading fill, if suitable, while any excess material would be disposed of at appropriate 

locations across the core site. Conversely, where there is a shortfall of materials for access 

road construction, borrow areas will be established at suitable locations. 

Other facilities required in addition to the turbines include: 

• Temporary lay down areas during construction. 

• Temporary concrete batching plant. 

• Temporary erosion and sediment control measures. 

• Temporary offices, workshops, stores and staff facilities. 

• Electricity substation. 

• Temporary mobile crushing plant. 

• An underground transmission & fibre optic communication network between the 

turbines and substation. 

• Overhead transmission between the substation and the external transmission 

network. 

• A maintenance and operations building. 

• Two Meteorological masts (wind monitoring towers). 

In general, power from the site will be fed into the local Main Power 66kV Line which runs 

parallel to State Highway 1 from the south before following Burrows Road. An internal wind 

farm 33kV or 22kV network will be constructed to channel power generated by the WTGs to 

the substation. The internal network will generally be underground, typically following the 

access roads. One overhead circuit will be incorporated within the internal transmission 

network to span a gully between the substation near Road D and Road A as an 

underground route is impractical due to significant construction requirements. 

This Construction Effects and Management Report has been prepared to support the 

application for resource consent. It deals specifically with the civil and access road work 

required to construct the wind farm, together with the expected management measures that 

will be undertaken during construction and site rehabilitation. Transport of oversized and 

overweight turbine components from the Port of Timaru to the site together with any effects 

on public roads are addressed in a separate Traffic Impact Assessment report. 

Drawing Sheets 1 and 2 in Appendix A (Appendix A.1 Overall Site Development Plans) 

illustrates the proposed site location and layout. 

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2 Access Route, Turbine and Fill Site Selection 

2.1 Preliminary Design Criteria 

Preliminary design criteria for road access to turbine sites and the turbine platforms are 

governed by: 

1. The movement of equipment and materials that are necessary for installing WTGs. 

2. The size and weight of the tower sections, blades and nacelle units. 

3. The mobility of the main erection crane along access roads and at the turbine 

platform. 

Equipment sizes and transport needs were discussed with potential turbine manufacturers, 

haulage companies and cranage service providers to derive preliminary design criteria for 

the access roads. Meridian has gained significant experience from the construction of 

Project Te Apiti (completed in 2004), Project White Hill (completed in 2007), Project West 

Wind (completed in 2009) and Te Uku (currently under construction). This experience has 

also contributed to deriving the preliminary design criteria. Typical characteristics of these 

plant items and indicative access road/platform requirements are described as follows: 

(a) Tubular tower sections and blades 

Based on data provided by New Zealand haulage companies and experience from similar 

wind farm projects (Project Te Apiti, White Hill and West Wind), a minimum internal 

horizontal radius of 30m has been adopted for preliminary design purposes. A road width of 

up to 10m has been provided at such minimum curves. 

On a straight section of road, a minimum road/running surface of approximately 6m will be 

adopted to accommodate transporters hauling the tower sections and to ensure the safe 

passing of other vehicles and the main erection crane as described below. This minimum 

road width is adequate where the internal horizontal radius of the access road is greater 

than approximately 55m. The main access road from the public road network to the core 

site will be approximately 7m wide as it will be more trafficked than the internal core roads. 

In addition to providing an adequate road surface width, clearance beyond the edge of the 

road surface needs to be provided for the sweep of the overhanging blade where the road 

is on a curve. In general, if the internal horizontal radius of the road is less than 175m, the 

clearance required is examined on a case by case basis considering the following factors: 

• Road width. 

• Angle of departure. 

• Final trailer configuration. 

• Selected turbine type. 

• Height of blade above ground when transported. 

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Currently a minimum vertical curve radius of 200m has been adopted based on the ground 

clearance of a multi-axle platform trailer with 0.5m wheel articulation. It is recognised that 

this may be further reduced if the final trailer configuration permits. 

Where access road grades exceed 12.5%, we envisage that haulage of the heavier turbine 

components, such as tower sections and nacelles, may require additional tractor units, 

dozers, or assistance by winching. An upper bound gradient of 15% has generally been 

adopted. Steeper gradients may be applied at straight or broad sweeping sections if 

unavoidable, subject to a maximum limit of 20%. At tighter horizontal curves, the gradient 

has generally been limited to less than 12.5%. 

Appendix C illustrates typical tower and blade transport configurations. Actual transport 

configurations will depend on the selected turbine. 

(b) Nacelle units 

Depending on the turbine, nacelle units typically weigh 90 tonnes (which typically includes 

an 8 tonne transport frame). Typical road transportation details/schematics (provided by 

turbine manufacturers) are attached in Appendix C. An example of an off-road 

configuration is also illustrated. 

The minimum geometric criteria for transport of the nacelle units around the site are within 

the parameters assessed for the blade and tower sections. 

(c) Main erection crane 

An erection crane capable of lifting the tower sections, nacelle unit and rotors to the top of 

the towers (typically 80m) will need to access each turbine site. The erection crane 

proposed for this project may have a crane track width of up to approximately 5m. A 

photograph of a typical crane is shown on Photograph F1 in Appendix F. 

An access road width of approximately 6m is expected to accommodate the main erection 

crane based on its operational requirements. This width has been assumed for all roads 

within the core site although further detailed design may reduce this width down to 4.5m 

towards the end of roads and along spur roads depending on the final crane configuration. 

Based on feedback from cranage service providers, a maximum access road grade of 17% 

(5.7H:1V or 10 o ) is considered negotiable by a crawler crane that is unloaded with the boom 

up. The crane can also negotiate road grades in excess of 17% by removing the crane’s 

boom which may be required along a limited number of road sections. 

(d) Turbine platform at turbine locations 

The turbine platform at each turbine location is an integral part of the road access. The 

turbine platform merges with the road access to enable transporters to deliver turbine 

components and provide a working platform to both construct the turbine foundation and 

erect the turbine components. Turbine platforms and the access roads are constructed at 

the same time and therefore the preliminary design criteria for both are considered 

together. 

Based on experience gained at Project Te Apiti, Project White Hill and Project West Wind 

together with feedback from turbine manufacturers and cranage service providers, a 

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minimum platform size of between 40m x 20m and 50m x 35m will be required for turbines 

depending on the specific crane selected and ridge positions. 

Examples of typical foundation working platforms at Project White Hill and Project West 

Wind, during the turbine component erection phase are shown on Photographs F2 to F6 in 

Appendix F. 

The proposed approach for rotor assembly is to fit the hub followed by the rotor blades one 

blade at a time. An alternative option, also known as the single lift approach, is to assemble 

the rotor and hub on the ground before lifting the assembly as one unit onto the turbine. 

The turbine platforms have been sized based on the proposed approach as the platform 

area can be reduced which is beneficial given the site’s hilly terrain. 

Photograph F7 and F8, from Project White Hill and Project West Wind respectively, in 

Appendix F illustrate the blades being lifted and assembled on to the turbine one at a time. 

Based on the above requirements, the parameters outlined in Table 1 have been adopted 

for preliminary design. 

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Design Aspect 

Main Construction Access 

Road To Turbine A11 

Internal Construction 

Access Roads (traversable 

by crawler crane) 

Maintenance road (postconstruction) 

Preliminary Criteria Adopted 

Approximately 7m wide with a 1.0m drainage channel. 

Drainage channel to be provided on both sides in box 

cuts. 

Localised widening to approximately 10m at internal 

radii approaching 30m. 

Approximately 6m wide with a 1.0m drainage channel. 

Drainage channel to be provided on both sides in box 

cuts. 

Similar to construction access. 

Pavement maintenance to 5m central strip only. 

Gradient Preferred < 5% 

Normal


All planning and wind modelling studies leading to this final layout have focused on 

achieving the maximum number of technically feasible turbine sites on the ridges based on 

the design criteria, landowner consent and site geology. The design process adopted to 

develop the feasibility layout is described below. 

(a) Wind Model 

Meridian developed initial turbine positions based on minimum turbine separation of 

approximately 5 rotor diameters and 4 rotor diameters to the prevailing upwind and 

crosswind direction respectively. This clearance is necessary to avoid turbulence effects 

and ensure a smooth laminar air flow. When combined with the terrain/layout of the ridges, 

this separation requirement places a constraint on turbine placement. 

(b) Desktop Review 

Initial turbine positions were reviewed against aerial photographs and 5m contour data 

which were obtained specifically for the site. The primary focus of this desktop review was 

to identify terrain constraints and potential encumbrances (survey trigs, transmission line, 

etc) to the proposed turbine positions in view of the preliminary design criteria for access 

roads and turbine platforms summarised in Table 1. Turbines which appeared to be 

physically located on or near steep slopes, gullies, local depressions, watercourses, or 

other potentially unfavourable terrain were noted prior to the micrositing phase which is 

described below. 

Other criteria and key aspects considered in developing the turbine and access road layout 

included: 

• Where possible, access routes were chosen to follow existing tracks, disturbed 

areas such as fence lines, contours and ridgelines to reduce environmental effects 

and to minimise the earthwork footprint. 

• Generally a cut-to-fill approach was adopted where practicable. On steeper terrain, 

a cut-to-waste approach was adopted given the difficulty of fill containment on 

steeper slopes. 

• Taking into account or avoiding where possible: 

 

 

 

 

 

 

Existing trigonometric stations. 

Large rock outcrops/formations or other significant natural features. 

Undisturbed watercourses. 

Damp or boggy areas. 

Areas of high ecological value. 

Steep slopes which are typically slopes > 28 o (refer Figure 4 – Site Slope 

Analysis Plan in Appendix D). 

• Any landowner requirements. 

(c) Micrositing 

Micrositing involved both Opus and Meridian locating each turbine position in the field to 

confirm access and turbine platform feasibility. Turbines were located in the field using a 

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hand held GPS receiver with an accuracy of +/- 6 to 12m. Turbines located in unfavourable 

positions as described above were moved to a more suitable position within the constraints 

of optimal wind generation. Turbines which were repositioned following micrositing are 

described below: 

• Turbine E1 was relocated approximately 20m away from a prominent rocky outcrop 

(Refer Photograph 12 in Appendix B). 

• Turbine A4 was relocated approximately 20m to the west to reduce excavation and 

ensure the turbine platform was integrated with Road A as indicated on Photograph 

17 in Appendix B. 

(d) Access Tracks 

Following the site-based micrositing exercise, sections of the road that were on particularly 

complex terrain were modelled to confirm feasibility. Earthworks quantities were 

subsequently derived using the following approach: 

• All sections of road were modelled using MXRoad (computer-aided three 

dimensional road design package) to derive preliminary longitudinal alignments and 

cross sections. For sidling cuts in steeper terrain, a cut to waste philosophy was 

generally adopted with cross sections examined for areas of unacceptable cut or fill. 

At areas of unacceptable cut or fill minor refinements to the preliminary longitudinal 

alignments and cross sections were made to ensure these areas remained within 

acceptable limits. 

• All earthworks have been estimated using MXRoad generally using a cut-to-waste 

approach including areas of gentler terrain to give an upperbound earthworks 

quantity and demand on fill site capacity. Fill embankments have been adopted only 

along sections of the route where longitudinal gradient and vertical curvature 

requirements (refer Table 1 Preliminary Design Criteria) could not be met. However 

during detailed design a cut-to-fill approach is envisaged which would result in a 

reduction of cut-to-waste earthworks. 

Drawing Sheets 11 to 14 in Appendix A (Appendix A.2 Access Road Plans & Cross 

Sections) illustrate the proposed turbine locations and derived access road layout from 

MXRoad. Roads indicated in the drawings have been identified alphabetically, while 

turbines are referenced to the road on which they are located. The final access layout and 

position of the turbines will be confirmed following a site survey, detailed design and the 

geotechnical/foundation conditions as encountered at each site. 

Approximately 22% of the proposed access roads will comprise upgraded existing tracks 

(with some localised corner smoothing and widening to approximately 10m). 

2.4 Spoil Fill Site Selection 

Selecting fill sites for excess excavated material will be generally driven by the following 

criteria: 

1. Environmental- Sites suitable as fill sites include: 

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• Local shallow depressions or the tops and upper reaches of natural dry gullies with 

good containment are favoured for compaction, aesthetics, rehabilitation and to 

reduce the risk of erosion and damming of natural drainage paths. 

• Well drained, broad and gentle terrain is also suitable to ensure minimal impact to 

natural flow paths. Fill material can be shaped to reinstate natural flow paths or to 

create alternative drainage paths as well as blend into the terrain. 

Sites not suitable as fill sites are: 

• Boggy or wet areas. 

• Gullies or valleys with perennial watercourses. 

• Steeper areas where fill cannot be contained in particular slopes. 

• Areas of high ecological value. 

2. Haul Length - The haul length to and from fill sites needs to be minimised wherever 

possible to maximise efficiency and to minimise plant traffic. 

3. Geotechnical – Avoid obvious areas of seepage and soft, steep or unstable areas. 

Several potential fill sites, near turbine positions and along proposed access roads, have 

been identified within the site to accommodate the projected volume of earthworks. These 

have been identified by desk top study and site visits. Photographs 50 to 58 in Appendix B 

illustrate some of these potential fill sites. 

The extent and final position of each fill site will be determined during the detailed design 

phase and will be based on the criteria outlined above and the proposed construction 

methodology. Refinement of fill site layouts will take place under the framework of the 

Environmental Management Plan (EMP) for the site which is outlined in Appendix E. 

As part of the process for selecting final fill sites, the design/construction team will discuss 

the location, size and depth of potential fill sites with respective landowners, relevant 

stakeholders (Councils or other) and the project environmental team to incorporate their 

requirements. The fill site selection strategy will involve selecting sites of limited size to 

control the area of disturbance and control later re-generation. The site selection strategy 

will also consider visual effects by aiming to keep fill areas “internal” to the site so that they 

are obscured from external view as far as possible. 

2.5 Assessment of Effects & General Consultation 

During the development of the preliminary engineering plans, the proposed wind farm 

layout was discussed amongst Meridian's assessment of environmental effects (AEE) team 

comprising transmission, ecological, noise, planning, traffic, landscape, cultural and 

archaeological specialists. 

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The AEE team also met on site to discuss the project layout. A key outcome of the process 

was the endorsement of the identified turbine sites and road alignments by the assessment 

team, in particular: 

• Identification and the accurate location of any archaeological, cultural and ecological 

sites of significance. 

• Identifying preferred main access routes and turbine locations (if necessary) to avoid 

environmentally, culturally and archaeologically sensitive areas. 

• Criteria for fill site (and borrow area) selection: Avoiding (as identified in Ecological 

Values and Assessment of Effects report prepared by Boffa Miskell): 

 

 

Covenanted areas such as the recently covenanted QEII land within the 

Turnbull property. 

A totara forest remnant within the Batchelor property. 

• Avoiding where possible (as identified in Ecological Values and Assessment of Effects 

report prepared by Boffa Miskell): 

 

 

Areas of higher ecological value. 

2.6 Implementation Team Review 

Areas for fill sites and construction works within the Motunau and Cave 

hydrological catchment areas by locating these areas in neighbouring 

northern catchments. This is because the northern catchment areas have 

been assessed as having less sensitive receiving environments than the 

Motunau and Cave receiving environments. This is generally feasible where 

these construction areas straddle both catchments. 

Meridian’s project construction implementation team completed a site visit on 15 April 2009 

and 30 July 2009 to provide input and feedback on the proposed layout based on 

experience from other Meridian wind farm projects including Project Te Apiti, Project White 

Hill and Project West Wind. 

Input from this process contributed to: 

• Refining the layout of access roads and turbine positions. 

• Updating construction timeframes and construction sequencing (discussed in Section 

6). 

• Refining the lay down area strategy and selection. 

• Identifying a potential site office area and lay down areas. 

• Identifying potential substation area. 

• Identifying internal transmission route options. 

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• Refining the criteria for fill site selection criteria as well as identifying potential fill sites. 

2.7 Access Options 

This section describes the access options considered for hauling wind turbine components 

to the core site together from the public road network with a description of the preferred 

route. A separate Traffic Impact Assessment (TIA) has been compiled to: 

• Assess any impact on traffic together with any proposed means of mitigating impacts. 

• Assess route options to transport components from port to site. 

2.7.1 Access Objectives 

The principal objectives in determining the main access from the local road network are: 

• To minimise impact on the environment. 

• To manage disruption to other road users and the public road network. 

• To maximise the efficiency of material transport. 

2.7.2 Core Site Access Options From The Local Public Road Network 

This section describes the access options considered from the local public road network to 

the core site. 

Several potential access options were assessed as indicated below and on Drawing Sheets 

3 and 4 in Appendix A (Appendix A.1 Overall Site Development Plans). 

Southern Access Options via Reeces Road 

1) Southern Access Road Option 1 via Reeces Road (Stevenson Property) 

2) Southern Access Road Option 2 via Reeces Road (Turnbull Property) 

3) Southern Access Road Option 3 via Reeces Road (Turnbull Property) 

Western Access Options via SH1 

1) Western Access Road Option 1 via SH1 (MacFarlane Property) 

2) Western Access Road Option 2 via SH1 (MacFarlane Property) 

3) Western Access Road Option 3 via SH1 (Sowden Property) 

Northern Access Options via Motunau Beach Road 

1) Northern Access Option 1 Road via Motunau Beach Road (Batchelor Property 

2.8km from SH1) 

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Each option is discussed below. 

Southern Access Options via Reeces Road 

1) Southern Access Road Option 1 via Reeces Road (Stevenson Property) – Approx 

2.2km Long 

This route begins at the entrance to the Stevenson’s residence on Reeces Road 

approximately 5.9km from the intersection of Reeces Rd with SH1. This route utilises the 

existing driveway up to the Stevenson residence, approximately 600m long, before 

following a newly formed access road approximately 1.6km long to access the southern end 

of Road D at turbine D1. 

The majority of this southern access option route involves moderate earthworks with 

minimal road cuts apart from the initial section of this route as it climbs the side of the ridge 

in a sidling cut. This route was ruled out as it utilised the existing Stephenson driveway and 

there are no other viable options to circumvent this section of the route. 

2) Southern Access Road Option 2 via Reeces Road (Turnbull Property) - Approx 

2.4km Long 

This route begins at the Turnbull entrance off Reeces Road, approximately 7km from the 

intersection of Reeces Rd and SH1. This route is approximately 2.4km long and generally 

follows an established farm track to Road A between turbines A1 and A2. 

This option involves extensive earthworks, significant geotechnical risks and environmental 

concerns associated with 2 stream crossings and working along the valley floor adjacent to 

a stream. This option was ruled out due to the geotechnical risks associated with the road 

cuttings along the steep sided ridge to Turbine A1 and the environmental impact associated 

with the stream crossings and section along the valley floor. 

3) Southern Access Road Option 3 via Reeces Road (Turnbull Property) - Approx 

2.7km Long 

This option commences at the southwest end of the Turnbull property, approximately 7.6km 

from the intersection of Reeces Rd and SH1. Rather than traverse the side of the main 

ridge to reach Road A, as does the previous option, this route generally runs along the main 

ridge following 2 stream crossings, both requiring culverts, at the beginning of the route. 

This option was also ruled out due to extensive earthworks and the environmental impact 

associated with the 2 stream crossings at the beginning of this route. 

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Western Access Options via SH1 

1) Western Access Road Option 1 via SH1 (MacFarlane Property) - Approx 3.1km 

Long 

The western access begins at the main entrance to the MacFarlane property, approximately 

4.4km north from the junction of SH1 with Reeces Road. This route passes over a railway 

crossing and typically follows an existing farm track which generally runs along side the 

MacFarlane property’s southern boundary up to Road D between turbines D2 and D3. This 

section is illustrated on Photographs 64, 65 and 66 in Appendix B. 

This option was also ruled out due to extensive earthworks, the environmental impact 

associated with the stream crossing at the beginning of this route and the potential issues 

associated with the rail crossing. 

2) Western Access Road Option 2 via SH1 (MacFarlane Property) - Approx 2.5km 

Long 

This option begins approximately 7.8km north from the junction of SH1 with Reeces Road 

and generally follows an existing farm track to Road D between turbines D10 and D11. 

Sections of this route are illustrated on Photographs 67 and 68 in Appendix B. 

This option was also ruled out due to extensive earthworks and the environmental impact 

associated with the stream crossing at the beginning of this route. 

3) Western Access Road Option 3 via SH1 (Sowden Property) - Approx 1.8km Long 

This option begins approximately 11km from the junction of SH1 with Reeces Road and 

climbs a low lying ridge to Road D at Turbine D14. This option involves less earthworks and 

less environmental impacts than the other western access options described above but still 

requires significant earthworks with gradients up to approximately 20% and a maximum cut 

height of approximately 20m. 

This option was ruled out in favour of the northern access options described below. 

Northern Access Options via Motunau Beach Road 

Four access options from the north were considered and are described below. The first 

option considered provided the most direct route to the turbines but passed close to 

neighbouring landowners the Guards and the Symmonds. Three further options were 

considered following consultation with these landowners. These three options are also 

described below. 

1) Northern Access Option 1 via Motunau Beach Road (Batchelor Property) – Approx 

2.2km Long 

This route commences at the intersection of Motunau Beach Road and the Batchelor/Daly 

property approximately 2.8km from SH1. The initial section of this route avoids the main 

access to the Batchelor residence and nearby farm buildings by running parallel to the 

existing Batchelor/Daly access before linking up with and generally following the main farm 

track along an east to west running ridgeline to Road A near Turbine A11. 

5C-1604.02 

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This route has no stream crossings and the least earthworks of all the northern options 

investigated. However the initial section of this route passes close to the boundaries of two 

adjacent landowners (Guard and Symmonds) to the north. 


2.2km Long 

This route commences at the intersection of Motunau Beach Road and the Batchelor/Daly 

property approximately 3.2km from SH1. This route was considered following consultation 

with the adjacent landowners identified above. The initial section of this route commences 

approximately 400m further south of the Option 1 above and offers a significant separation 

from the adjacent landowners. The route travels west across two stream crossings and 

climbs the next ridgeline south of Option 1 in deep box cuts to meet Road A at Turbine A11. 

This route requires extensive cuts reaching approximately 30m and steep gradients up to 

20%. 

This option was ruled out due to extensive cuts, steep gradients and the environmental 

impact associated with two stream crossings. 


2.4km Long 

This route commences at the same location of Option 2 above and was also considered 

following consultation with the adjacent landowners identified above. This route also travels 

west across one stream crossing but climbs another east to west running ridgeline south of 

Option 2. This route requires significant earthworks and steep gradients up to 20%. The box 

cuts required along this route are not as deep as Option 2 and are expected to reach 

approximately 16m. 

This option was ruled out due to significant earthworks and the environmental impact 

associated with the stream crossing. 


2.5km Long 

This route also commences at the same location of Options 2 and 3 above following 

consultation to provide a significant separation from the adjacent landowners. However this 

route avoids the stream crossings associated with Options 2 and 3 above by following the 

same ridgeline utilised by Option 1 to meet Road A at Turbine A11. To maintain a 

reasonable separation between the adjacent landowners this option climbs along the 

southern side of ridgeline for approximately 800m before following the same route as 

Option 1 to reach Turbine A11 at Road A. The maximum gradient expected along this route 

is approximately 15% and a maximum box cut of approximately 18m. 

This route requires greater earthworks than Option 1 as a result of providing a reasonable 

separation from the adjacent landowners but like Option 1 involves no stream crossings. 

This option was selected for the following reasons: 

• Provides the most technically feasible option with respect to earthworks while 

maintaining a reasonable separation from adjacent landowners. 

5C-1604.02 

February 2011 15


• 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. 

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• 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. 

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February 2011 17


Approximately 22.2km of internal access roads will be required to access the turbine sites. 

These roads, designated alphabetically from Road A to H, have been planned with nominal 

widths of 6m and 7m. Roads on which main cranes are expected to traverse fully rigged 

have been planned with a nominal road width of 6m. The main access road which leads to 

the core site roads has also been planned with a nominal width of 7m. Additional minor 

tracks are required for construction of the transmission towers that support the transmission 

line between the proposed substation and external 66kV transmission line. These will be 

approximately 3.0m wide. 

The 22.2km of roads comprise approximately 5.2km of upgrading of existing farm tracks 

with the balance, approximately 17km, being new roads. 

The northern access road is the primary internal access road into the site and links with 

Road A at the northeastern section of the site. Road C provides the east to west link from 

Road A to Roads D, E, F, G and H. 

The layout of the roads to turbine sites will be reassessed during detailed design to align 

with the final turbine positions and terrain as determined after detailed survey and 

geotechnical investigations. Each core site access road is described in detail below with 

references to photographs in Appendix B illustrating the location of roads and turbines in 

relation to the topography. The relationship between access roads and turbine platforms to 

the topography is also illustrated in the Truescape graphical attachments to the Landscape 

Assessment Report prepared by Peter Rough Landscape Architects Ltd. 

Northern Access Road 

The northern access road, at nominally 7m wide along its entire length, will be the principal 

access into site for all the construction plant, materials and WTG components. This road 

commences at a new entrance off Motunau Beach Road approximately 3.2km from SH1. 

From Motunau Beach Road this route runs across the Batchelor/Daly property. The initial 

section of this route runs west across a flat paddock before turning north in a wide 

sweeping bend adjacent to the proposed laydown area and site offices (refer Photographs 

1 and 2 in Appendix B). 

From this point the route runs just to the west of the Batchelor/Daly dwelling before turning 

west and climbing the beginning of a gentle ridge adjacent to some farm buildings as shown 

on Photograph 3 in Appendix B. From this point the route continues to ascend along the 

southern side of this gently rising ridge in a series of moderate sidling and box cuts at a 

gradient of approximately 11% to just prior to the forested section. The route then traverses 

through the forested section in a large box cut with a maximum height of approximately 

18m at a gradient of approximately 15%. This section is illustrated on Photograph 4 in 

Appendix B. 

The northern access road rejoins the existing track as it leaves the forested section and 

follows it in a tight horizontal curve around a steep sided ridge in a sidling cut as illustrated 

in Photograph 5 in Appendix B. Just prior to the bend the route steepens to approximately 

16% before easing to approximately 7% as it enters the curve. Along with the section of cut 

through the forest this is the most technically challenging section of the route and will 

5C-1604.02 

February 2011 18


comprise extensive earthworks with sidling cuts up to approximately 17m in height as 

shown on Photograph 5 in Appendix B. 

Once the route leaves the tight bend it continues to traverse the ridge in a sidling cut to the 

ridge top at a gradient of approximately 15%. From this location the route generally follows 

the ridge in a series of cuts and fills to join with Road A at Turbine A11 as shown on 

Photographs 6, 7 and 8 in Appendix B. 

Road A 

Road A is typically 6m wide (apart from the section between Turbines A11 and A9) and 

generally runs along one of the two main project ridgelines running in a north-east to southwest 

direction. Road A begins in the northeast section of the site at turbine A11 and 

terminates at the southwest section of the site at turbine A1. 

Road A runs along gentle to moderately undulating terrain in a series of moderate cuts and 

fills from Turbine A11 to Turbine A8. The maximum gradient along this section is 

approximately 15% just prior to Turbine A8 with a corresponding maximum cut height of 

approximately 5m. Photograph 23 in Appendix B illustrates Road A between Turbines A9 

and A10 while the section just prior to Turbine A8 is shown on Photograph 13 in Appendix 

B. 

Between turbines A8 and A7 Road A generally descends following the ridgeline reaching a 

maximum gradient of about 13% prior to leveling out at Turbine A7. Beyond Turbine A7 

Road A descends at approximately 14% before rising along the ridgeline south towards 

Road C and Turbine A6. The section of Road A beyond Turbine A7 is illustrated on 

Photograph 14 in Appendix B. 

From Turbine A6 Road A descends gradually to turbine A2 generally following the broad 

ridgeline in minor cuts and fills. This section is shown on Photographs 15 to 20 in Appendix 

B. 

The final section of Road A from turbine A2 descends at a moderate gradient before rising 

sharply to turbine A1 which is located at the top of a steep sided knoll. In order to reach 

turbine A1 a box cut with a maximum cut height of approximately 7m will be required at a 

maximum gradient of approximately 20%. This section is illustrated on Photographs 21 and 

22 in Appendix B. 

Road B 

Road B follows a secondary ridgeline which branches off from Road A between turbines A4 

and A3. Road B crosses the upper reaches of a gully, which will require a fill embankment 

and culvert, approximately 100m from its intersection with Road A. Road B descends at a 

moderate gradient reaching a maximum of 13% before leveling off to access Turbine B1. 

This section is shown on Photograph 24 in Appendix B. From Turbine B2 Road B 

descends for approximately 300m before climbing at a gradient of about 15% in a box cut 

with a maximum cut height of 5m over a distance of approximately 100m. The remaining 

section of Road B is relatively flat as it terminates at Turbine B1. Photograph 25 in 

Appendix B illustrates Road B at Turbine B1 while Photograph 26 shows Road B as viewed 

from Turbine A1. Road B is 6m wide. 

5C-1604.02 

February 2011 19


Road C 

Road C links Road A with Road D as well as servicing turbine C1. Road C runs at a 

relatively flat gradient from Road A and rises at approximately 15% prior to traversing the 

upper slopes of a steep knoll. A maximum cut height of approximately 10m is reached as 

Road C traverses this knoll to access the turbine platform for Turbine C1. Beyond Turbine 

C1 Road C descends in a moderate gradient winding gently between knolls to Road D. 

Road C crosses the upper reaches of a small gully, which will require culverting, just prior to 

Road D. This section is illustrated on Photograph 27 in Appendix B. 

Road D 

Road D is approximately 6m wide and typically follows one of the main project ridgelines 

(the other being Road A) running in a north-east to south-west direction. Road D begins in 

the northeast section of the site at turbine D14 and terminates at the southwest section of 

the site at turbine D1. 

The route between turbines D14 and D13 descends at a maximum gradient of 

approximately 5% before leveling at a saddle. From the saddle Road D steadily climbs to 

reach the short link road to Turbine D13. A maximum gradient of approximately 20% is 

expected along this section prior to the link to Turbine D13. This section is illustrated on 


Road D rises gently from Turbine D13 to Turbine D12 along moderately undulating terrain. 

Between Turbines D12 and D11 Road D rises in an embankment fill at a maximum gradient 

of about 17% and a corresponding maximum embankment fill of approximately 5m in depth 

before leveling off just prior to Turbine D11. From Turbine D11 to Turbine D10 the 

horizontal alignment of the route is relatively straight and the gradients relatively flat. Minor 

earthworks are expected along this section. 

Between Turbine D10 and Turbine D7 Road D comprises sections of cuts and fills to 

maintain acceptable gradients as it continues to follow a broad ridgeline along gently 

undulating terrain. The cut heights along this section are modest and remain under 5m. 

Photograph 29 in Appendix B illustrates the terrain along this section of Road D. 

The topography changes between Turbines D7 and D2 where the ridgeline narrows and 

undulates sharply constraining Road D to run in a succession of sidling cuts and saddle fills 

to achieve acceptable grades and alignments. Photograph 30 illustrates the section of 

Road D between Turbines D7 and D5 while Photograph 31 shows the section of Road D in 

the vicinity of Turbine D5. In order to ease the gradient of Road D prior to Turbine D5 a fill 

embankment is proposed across a narrow saddle as shown in Photograph 31. The 

maximum height of this fill embankment is approximately 16m and it is expected that 

suitable material from nearby road cuts will be used as structural fill. From Turbines D5 to 

D4 Road D descends along the sharply undulating ridgeline reaching a maximum gradient 

of approximately 15%. The maximum cut height along this section is approximately 10m 

which represents the largest road cut along Road D. Between turbines D4 to D2 the 

ridgeline, although narrow, is less undulating and road D descends in a series of modest 

cuts and fills reaching a maximum gradient of 15% over a length of approximately 300m. 

Photograph 32 shows this section of Road D between turbines D4 and D3 while 

Photograph 33 shows Road D between Turbines D3 and D2. 

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February 2011 20


The route between Turbines D2 and D1 is relatively flat with minor earthworks expected. 

Road D comprises gently undulating broad ridgelines at the northeast and southwest ends 

of this route but more complex and technically challenging terrain along the middle section 

as described above. 

Road D1 

Road D1 provides access to Turbines D6 and D7 and runs along gently undulating terrain. 

Minor earthworks are expected along this route which is shown on Photographs 38 and 39 

in Appendix B. This road is approximately 6m wide. 

Road D2 

Road D2 comprises a short section of road to access Turbine D9. This route is relatively 

flat and only minor earthworks are expected. Road D2 and Turbine D9 are shown on 


Road E 

Road E at approximately 6m wide commences at the intersection with Road D between 

Turbines D5 and D7 and circles around the outside of steep sided localised ridge in both 

sidling and box cuts to a point where both Turbines E1 and E2 can be accessed along 

alignments with reasonable gradients. The maximum cut height is approximately 7m with a 

corresponding maximum gradient of approximately 15% as Road B circles outside a steep 

sided ridge. Road E is shown on Photographs 34 and 35 in Appendix B. 

Road F 

Road F runs along a spur running approximately perpendicular to Road D near turbine D11. 

A series of moderate cuts and fills characterise Road F as it descends along moderately 

undulating terrain to reach turbine F1. Road F is approximately 6m wide. 

Road G 

Road G is approximately 6m wide and services turbine G1 which is located along a spur 

running perpendicular to the Road D ridgeline as shown on Photograph 36 in Appendix B. 

This route descends from Road D in a moderate sidling cut reaching a maximum down 

slope gradient of about 12% before leveling off in a fill embankment across a narrow 

saddle. Road G rises at a gentle gradient of approximately 5% from this saddle in a 

shallow box cut to reach turbine G1. The maximum cut height along Road G is 

approximately 6m. 

Road H 

Road H descends along a gently undulating spur running in a southeast direction 

perpendicular to Road D. The majority of the earthworks are concentrated at the latter 

section of this route where a maximum cut height of approximately 6m is expected. Road H 

is shown on Photograph 32 in Appendix B. Road H is approximately 6m wide. 

3.2.2 Access Road Formation 

Typical Cross Sections and Extent of Cuts 

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Table 2 indicates the typical access road cross sections for the different terrain types with 

cut slopes expected in the region of 1H:2V to 1H:4V. Fill slopes, where applied, are 

expected to be in the region of 2H:1V as tabulated in Table 3. Typical cross sections are 

illustrated on Drawing Sheet 10. Drawing Sheets 8 and 9 illustrate the sections of access 

road where these typical cross sections apply. The longitudinal extent of cuttings (length 

along the access roads) can be approximated to the linear length of each section identified. 

Side Slope at Road Location Typical Cut Slope Typical Cut Height 

Road running on ridgeline, in shallow 

box cut, or relatively flat land. 

(Section A – Drawing Sheet 10) 

None 

through to 1H : 4V. 

Up to approximately 

1.5m. 

Road in sidling cut with side slopes up 

to 20% (1V:5H) 

(Section B – Drawing Sheet 10) 

Road in sidling cut with side slopes up 

to 40% (1V:3H) 

(Section C – Drawing Sheet 10) 

Box cuts on ridges, or in sidling cut 

situations. (Drawing Sheet 10) 

1H:2V 

1H:2V 

1H:2V 

2.5 to 3.5 metres. 

5 to 6 metres. 

1.5 to 6 metres. 

Table 2: Typical Cut Slope and Height 

Side Slope at Road Location Typical Fill Slope Typical Fill Depth 

Road running on relatively flat land or 

gentle slopes. 

(Typical Section in Fill – Drawing 

Sheet 10) 

Table 3: Typical Fill Slope and Height 

2H:1V 

Varies, up to 5m 

Typical cut heights of 2.5m to 6m described in Table 2 will be similar in scale to some of 

those visible along the existing tracks. Photograph 6 in Appendix B illustrates such a cut on 

the existing track following the proposed alignment of the northern access road. 

Photographs F9 (taken at project Te Apiti) and F10 and F11 (taken at Project West Wind) in 

Appendix F illustrate road cuts with approximate heights between 7m to 8m. 

Table 4 summarises sections where extremities of cut height are expected (ie batter heights 

greater than or equal to approximately 6m. 

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Location 

(approx) 

Approx. 

Maximum 

Batter 

Height of 

Cut (m) 

Approx. 

Length of 

Individual 

Extreme 

Cuts (m) 

Approx. 

Maximum 

Earthworks 

Width & 

Location 

Indicative 

Section in 

Drawing 

Sheets 15 

to 18 

Northern Access Road (1.0km 

from Motunau Beach Road) 18 350 31m @ 1300m 

Section 1 

Northern Access Road (1.5km 

from Motunau Beach Road) 17 140 20m @ 1550m 

Section 2 

Road A (Between A1 & A2) 7 130 

14m @ 350m Section 3 

Road A (Between Road C & A2) 7 40 



19m@890m Section 5 




19m @2710 Section 7 

Road C 10 150 


Road D (Between D1 & D3) 9 60 





18m @ 1020m Section 11 


18m @ 1510m Section 12 


17m @ 1730m Section 13 


15m @ 2020m Section 14 

Road E (Between Road D & E1) 7 50 


Road E (Between Road D & E1) 7 70 14m @ 290m Section 16 

Road G (Between Road D & G1) 6 100 


Table 4: Extremities of Cut Height (Batter Cut Heights >= 6m) 

Typical Cut 

Slope 

1H:2V (Benching at 5m intervals) 

The cumulative length of sections where the cut height is greater than or equal to 6m is 

approximately 1.6km, which equates to approximately 7% of the proposed total access road 

network. In this respect, sections with cut heights greater than 6m only occur along a relatively 

small proportion of the entire access road network. We note that preliminary geotechnical 

investigations suggest that cut faces greater than 5m height should be benched at 5m intervals. 

Therefore these sections identified in Table 4 will be benched. 

The maximum batter height referred to in Table 4 is represented as the height of the cut face from 

the toe of the cut to the top of the batter. This measurement is illustrated in Figure 2 below. 

5C-1604.02 

February 2011 23


Figure 2 – Batter Height of Cut 

Table 5 tabulates sections where fill depths are expected to exceed typical depths. Typical 

cross sections at these extremes are illustrated in Drawing Sheets 15 to 18. The total 

length of road with cuts greater than or equal to 6m is 1.58km. 

Location 

(approx) 

Approx. 

Maximum 

Fill 

Depth(m) 

Approx. 

Length of 

Individual 

Fill Sections 

(m) 



Road E (Between Road D & E1) 5 40 

Table 5: Extremities of Fill Depth (Fill Depths >= 5m) 

Approx. 

Maximum 

Earthworks 

Width & 

Location 

60m @ 

STA1370 

13m @ STA 

2250 

22m @ STA 

50 

Indicative 

Section in 

Drawing 

Sheet 18 

Section 21 

Section 22 

Section 23 

Typical Fill 

Slope 

2H:1V 

Geotechnical investigations and observation during construction will also identify any areas 

of cutting with a potential for seepage, such as any areas with high groundwater pressure 

within the bedrock. Where seepage is likely to occur, measures such as horizontal 

drainage, or subsoil drains can be provided to control erosion. However, given the geology 

of the formation and observations on site, groundwater is unlikely to be of significant 

concern. 

As the works progress, the aim will be to rehabilitate (as appropriate) exposed cut and fill 

slopes as soon as is reasonably practicable. A requirement to this effect will be included in 

the construction contract documentation and will be included as part of the proposed 

conditions of consent. Rehabilitation for cuts in soil and fill slopes will use the most 

practical and effective re-vegetation techniques available at the time the work is required. 

Revegetation techniques are discussed in more detail in the Ecological Values and 

Assessment of Effects report prepared by Boffa Miskell and incorporated in the 

Environmental Management Plan prepared by Tonkin and Taylor. 

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Estimated Cut Volumes 

The pessimistic volume of earthworks associated with formation of the access roads, based 

on the preliminary investigations to-date, is summarised in Table 6 below. The pessimistic 

earthworks volumes are calculated as 15% over and above the “most likely” earthworks 

volumes determined from MXRoad (computer-aided three dimensional design package). 

The volumes presented represent the upper bound of materials as we have assumed that 

earthworks will be undertaken on a cut-to-waste approach. Actual excess excavated 

material will be lower given that a cut-to-fill approach will be applied during detailed design. 

Table 6 below also shows that approximately 5.2km of access roading comprise of existing 

tracks which equates to approximately 22% of the total length of access roads. 

Road 

Approximate 

Length (km) 

Approx portion 

comprising upgraded 

existing tracks (km) 

Cut Only 

(m 3 ) 

Northern Access Road 2.5 1.8 123,000 

Road A 5.8 1.4 98,000 

Road B 1.9 17,000 

Road C 1.4 30,000 

Road D 7.3 1.8 121,000 

Road D1 0.5 6,000 

Road D2 0.3 4,000 

Road E 0.9 11,000 

Road F 0.6 4,000 

Road G 0.8 16,000 

Road H 0.5 0.2 5,000 

Project Total 22.5 5.2 435,000 

Table 6: Estimated Access Road Excavation Volumes 

Access Road Surfacing 

Access roads will typically be unsealed with a basecourse running surface. Roads will be 

categorised as to the level of construction traffic on them with an expected design depth of 

basecourse between 100mm and 200mm depending on traffic levels and ground 

conditions. 

Initial geotechnical investigations suggest that material sourced within the project area from 

excavations for the access roads, working platforms and foundations is unlikely to be of 

sufficient strength to provide an adequate source of basecourse. We have observed that 

the quality of bedrock is variable (ranging from fresh and unweathered to exposed and 

weathered). Further detailed geotechnical investigations will be required to confirm 

whether on-site material is suitable for use as a basecourse. In the event suitable material 

is available on site excavated materials can be stockpiled at localised processing areas 

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where a mobile crushing plant will be employed to produce the required grade of 

basecourse material. This is discussed in more detail in Section 3.2.8 on borrow areas. 

In some circumstances, where longitudinal grades of principal roads exceed 15-18%, it is 

possible that the 5m central portion of the road may be sealed to improve traction and 

reduce maintenance needs. Any pavement seal is likely to comprise chip seal depending 

on the maintenance strategy developed during the detailed design stage. 

3.2.3 Turbine Platforms 

While the maximum foundation base is expected to be approximately 16m to 18m in 

diameter (depending on final turbine and ground conditions), a larger flat area is required to 

accommodate the main tower and turbine erection cranes. Drawing Sheet 80 of Appendix 

A.5 shows generic requirements for a flat working platform. The area required will depend 

on the final crane configuration and any site specific constraints. 

The pessimistic volume of excavation associated with platform construction based on an 

upper bound 50m x 35m platform is summarised in Table 7. 

Road Nos. of Turbines Cut (m 3 ) 

Road A 11 84,000 

Road B 2 11,000 

Road C 1 13,000 

Road D 12 69,000 

Road D1 1 6,000 

Road D2 1 2,000 

Road E 2 20,000 

Road F 1 3,000 

Road G 1 10,000 

Road H 1 7,000 

Project Total 33 225,000 

Table 7: Estimated Turbine Platform Excavation Volumes 

A maximum excavation depth of approximately 1.5m to 3m is typically required at sites on 

flat to gently rolling terrain to create the required platform area. However, sites with more 

undulating terrain require excavation greater than or equal to approximately 5m to create 

the required working platform area and/or to interface with the access road. Table 8 

summarises approximate average and maximum turbine platform excavation depths where 

the maximum platform cut height is expected to equal or exceed 5m. The approximate 

maximum cut depth presented, which represents the maximum height of cut that is likely to 

occur at the respective platform location, is illustrated in Figure 3 for three typical terrain 

types. 

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Photographs F12 and F13 in Appendix F show a turbine foundation at Project West Wind 

before and after concreting and backfilling. Photographs F14 and F15 in Appendix F show 

a turbine foundation and platform at the operational stage of Project White Hill. 

Approx Max 

Cut 

Hillside cut 

Approx Max 

Cut 

Ridge cut 

Approx Max 

Cut 

Saddle cut 

Figure 3: Approximate Maximum Cut Depth Definition 

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Road 

Turbine 

Approx. Cut Depth (m) 

Average 

Maximum 

A2 4 7 

A3 4 10 

A7 3 8 

Road A 

A8 4 5 

A9 3 5 

A10 5 10 

A11 3 6 

Road B B1 3 5 

Road C C1 5 9 

D5 2 6 

D6 3 5 

Road D 

D7 3 5 

D10 3 5 

D12 4 5 

D14 4 7 

Road E 

E1 5 7 

E2 4 5 

Road G G1 3 5 

Table 8: Turbine Platforms - Excavation Expected to Equal or Exceed 5m in Height 

3.2.4 Construction Footprint of Roads & Turbine Platforms 

The construction footprint of core site access roads including turbine platforms calculated 

from MXRoad and illustrated on Drawing Sheets 11 to 14 in Appendix A (Appendix A.2 

Access Road Plans & Cross Sections) is shown in Table 9 Below. 

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February 2011 28


Road 

Approximate 

Length (km) 

No. of Turbines 

Const. 

Footprint 

(m 2 ) 

Northern Access Road 2.5 33,000 

Road A 5.8 11 82,000 

Road B 1.9 2 21,000 

Road C 1.4 1 9,000 

Road D 7.3 11 111,000 

Road D1 0.5 2 8,000 

Road D2 0.3 1 4,000 

Road E 0.9 2 13,000 

Road F 0.6 1 6,000 

Road G 0.8 1 11,000 

Road H 0.5 1 7,000 

Project Total 22.5 33 305,000 

Table 9: Construction Footprint of Core Site Roads and Turbine Platforms 

3.2.5 Spoil Fill Sites 

During the earthmoving operation excess excavated material will be placed at clearly 

defined spoil fill sites. These locations will be selected during detailed design/construction 

in accordance with the criteria outlined in Section 2.4. In some locations material may also 

be utilised to aid localised shaping of the adjacent ground to blend in the construction 

works. 

Based on observations of the site, the majority of spoil fill sites will occupy areas of pasture. 

The total area required to dispose of the pessimistic earthworks cut volumes, within the site 

assuming a conservative average fill depth of 2.5m, would be in the order of 250,000m 2 

(0.25km 2 ). This represents just under 1% of the total land holding area of the site (34km 2 ). 

Given the landform’s potential to provide well contained sites, the fact that earthworks 

quantities are likely to be lower than the pessimistic value quoted and the sites are 

generally capable of holding greater than 2.5m depth of fill, the total area of potential fill 

sites is expected to be smaller than the figure estimated above. Photographs 50 to 58 in 

Appendix B provide examples of typical well contained fill sites throughout the core site. 

The criteria for avoiding areas of high ecological value (areas not suitable for spoil fill sites) 

have been assessed in the Ecological Values and Assessment of Effects report. The 

detailed design/construction team will consult landowners and other relevant stakeholders 

in the process of identifying and selecting the location and number of fill sites in accordance 

with the process outlined in the draft Environmental Management Plan (EMP) in Appendix 

5C-1604.02 

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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. 

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• 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. 

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Concrete 

Component 

Estimated Demand 

(Turbine 

Foundations) 

Estimated 

Demand Per 

Pour (Same 

Day) 

Approximate 

Indication of Average 

Demand 

Cement 3,200 tonnes 94 tonnes 3 x 23 tonne bulk 

carriers per day 

Sand and 

Aggregate 

27,000 tonnes 800 tonnes 13 x 23 tonne trucks 

per day 

Water 2.4 million litres 72,000 7 tankers (10,000 litre 

capacity) per day 

Table 11: Indicative Batching Plant Demand on Materials 

We envisage that measures to contain any dust, spillage and wash down of plant or trucks 

will be outlined in the contractor’s management plan. Such measures are likely to include 

cement storage within a silo, aggregate storage bins, a temporary concrete slab beneath 

the loading area and containment bunding around the plant. 

3.2.7 Borrow Areas 

Basecourse material may be sourced within the project area from excavations for the 

access roads, working platforms and foundations wherever practicable. Basecourse 

material may also be sourced from borrow areas within the site. However, an appraisal on 

the availability of suitable material on-site for processing roading and platform basecourse 

would be undertaken at the detailed design phase to determine whether suitable material is 

available on site. 

In the event that locally won materials will be suitable for road construction, borrow areas 

would be established at locations within the site which meet the same criteria established 

for fill sites (outlined in Section 2.4). Extracted materials will be stockpiled at localised 

processing areas where a mobile crushing plant will be used to produce the required grade 

of basecourse material. Material may also be extracted from these borrow areas for 

roading fill where there is a shortfall of suitable material excavated from road construction. 

The total pessimistic volume of basecourse required for roads, turbine platforms and 

laydown areas is approximately 41,000m 3 . Assuming this involves approximately 90% of 

the equivalent volume in overburden to extract this material and an average borrow site 

depth of approximately 3m the following construction footprint expected is approximately 

25,000m 2 . These details are summarised in Table 12 below. 

Total Volume of 

Basecourse (m 3 ) 

Equivalent Volume 

of Overburden (m 3 ) 

Total Combined 

Volume (m 3 ) 

Construction 

Footprint (m 2 ) 

41,000 35,000 76,000 25,000 

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Table 12: Potential Basecourse Volumes and Borrow Areas 

Should all basecourse be sourced on site the potential construction footprint would be 

approximately 25,000m 2 . This is minimal compared to the construction footprint of 285,000 

m 2 estimated for disposal fill areas associated with core site access roads and turbines 

(less than 10%). 

We expect the following activities and typical measures would be incorporated into the 

identification, design and operation of borrow areas, as appropriate: 

 

 

 

 

 

 

 

 

A site appraisal by the design/construction team, in consultation with landowners 

and other relevant stakeholders, to identify suitable borrow areas in line with the 

EMP. Areas of ecological value, particularly around rocky outcrops, as described in 

the road layout and fill site selection (Sections 2.3 and 2.4), will be avoided. 

Detailed soil investigation involving deep boring and trial pits at identified locations 

to confirm suitability for material extraction. 

Initial establishment of borrow area by site clearance followed by stripping and 

stockpiling topsoil. 

Establishing a mobile crushing plant. A typical mobile crushing plant comprises a 

hopper, jaw crusher, conveyor and screen attached to a tracked wheel vehicle. An 

excavator generally fills the hopper with material for processing into basecourse. 

Excavation, processing and stockpiling of materials. 

Fill of excess or unwanted materials at suitable fill site locations. 

Mitigation to control run-off and sedimentation. Sediment control measures, as 

discussed in Section 3.3 below, will be provided to manage sediment run-off during 

operation and until ground cover is established after rehabilitation of the borrow 

area.. 

Reshaping the borrow areas to blend in with the surrounding terrain, re-topsoiling 

(with material which has been removed and stockpiled) and re-vegetating. Measures 

will be discussed and agreed with landowner. Note that the overburden material 

extracted from borrow areas and other surplus material from the civil works may be 

used to fill in borrow areas prior to topsoiling. 

At Project West Wind a mobile crushing plant was established on site at a borrow area near 

Oteranga Bay to produce materials for core site access roading and turbine platform 

basecourse. This mobile crushing plant and borrow area is illustrated on Photograph F21 

in Appendix F. 

3.2.8 Soil Stockpile Areas 

Topsoil will be stockpiled throughout the site for re-topsoiling fill sites, platform areas and so 

on. Long-term stockpiles will be temporarily stabilised by hydroseeding or hydro-mulching, 

if necessary, to reduce erosion and sediment generation. 

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3.2.9 Site Lay Down Areas 

WTG components will be delivered from port to site ahead of installation. Therefore lay 

down or stockpile areas will be required for temporary storage of turbine components, as 

well as other materials such as electrical cables. Rather than creating multiple large lay 

down areas for the bulk storage of turbine components, Meridian proposes to store turbine 

components near turbine locations using the turbine platforms and storage lay-bys adjacent 

to access roads where possible. This is to allow for sufficient components/materials to be 

stockpiled on site to meet the demand of construction crews as well as to accommodate the 

arrival of several large shipments of components. Photographs F2 to F6 in Appendix F 

show how turbine platforms have been used to store turbine components while being lifted 

and assembled at both Project White Hill and Project West Wind. Photograph F22 shows a 

typical lay down area to store turbine blades at Project West Wind. 

The optimum and most strategic locations for storage lay-bys will be dependent on a more 

detailed study of the construction and installation sequences. At this stage potential 

storage lay-bys have been identified at the following locations: 

Near Turbine A9 along existing air strip as shown on Photograph 23 in Appendix B. 

 

Adjacent to the initial section northern access road as shown on Photograph 2 in 

Appendix B. 

3.2.10 Internal Cable Reticulation 

A 33kV or 22kV and fibre optic internal cable reticulation system is required to link the 

turbines to the substation. The internal cable layout developed for this project is a series of 

separate cable strings leading from the substation connecting all turbines along each main 

access road. These cables will generally be placed in trenches running along the formed 

access roads. It may be necessary to adopt some overhead reticulation to avoid hard, 

unstable or boggy ground or avoid a longer underground route only where the overhead 

line can be masked, or hidden from the skyline. For example an overhead line will be 

required to span a gully between Road D and Road A. Note this overhead line is internal to 

the site and any overhead reticulation would be constructed from monopole structures no 

taller than 20m. 

Typical trench dimensions could be 400mm to 600mm wide and 800mm to 1000mm deep. 

Where two cables run along a common road trenches will be located on either side of the 

road. Where off-road routes are required, trenching operations may require a working 

corridor of up to 5m (to form a cable trench) depending on the number and type of cables. 

Cable trenches will typically have a granular backfill to meet required thermal resistivity and 

engineered fill with pavement or topsoil (material which has been removed and stockpiled) 

layer above as appropriate. 

Where overhead routes are employed, routes will be selected to follow the access road and 

existing tracks/fencing corridors where possible. In the event a cross country route cannot 

be avoided, it is envisaged that overhead line construction will require the establishment of 

an appropriate corridor including access to any transmission poles. 

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Indicative cable trenching details are illustrated on Drawing Sheet 102 in Appendix A 

(Appendix A.7 Substation, Underground Cabling & Transmission Line Details). Photograph 

F23 in Appendix F shows a typical buried cable being constructed. 

3.2.11 Substation 

Substation Platform 

A substation will be required to connect the turbines to the Transmission grid. The 

proposed location for the substation is just south of Turbine D11 on the western side of 

Road D as shown on Drawing Sheets 81, 82 and 83 in Appendix A (Appendix A.7 

Substation, Underground Cabling & Transmission Line Details). The substation compound 

area will occupy an area approximately 79m by 46m. A maximum cut height of 

approximately 5m will be required on the edges of the construction footprint to create a 

single level platform for this substation as shown on Drawing Sheet 83. The indicative 

construction footprint, including batter slopes, and the pessimistic volume of excavated cut 

are shown in Table 13 below. 

Indicative Substation Footprint (m 2 ) Cut (m 3 ) 

5,000 16,000 

Table 13: Substation Construction Footprint and Cut Volumes 

Although detailed geotechnical assessment of the site has not been completed at this 

stage, ground conditions are unlikely to present any problems. Once the substation site is 

established, the surrounding area that has been disturbed will be re-vegetated as 

appropriate. 

Substation Buildings & Construction Activities 

The following activities will be required at this substation: 

 

 

Construction, maintenance and use of a substation switch room for housing a 

switchgear suite and associated equipment. The dimensions of the switchgear 

building are approximately 14m long, 11m wide and a height of no more than 6m. 

The switchgear building will be located within the substation perimeter fence. 

Construction, maintenance and operation of a switchyard located within the 

climb/predator/pest-proof fenced substation area. The switchyard will include 

switching gear, insulators, circuit breakers and a main transformer, lightning 

protection masts up to 20m tall), communication equipment and other associated 

equipment. The communication equipment will consist of either a maximum of two 

dishes mounted on the side of the substation building or on a 5m mast beside the 

building. 

The transformer will be oil filled and located within appropriately designed bunds to retain 

any oil leakage and avoid any contamination of the stormwater runoff in the unlikely event 

of an oil spillage. As such, it is envisaged that a low concrete bund will be provided around 

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the transformer together with a concrete ground slab. Oil-water interceptor tanks will be 

constructed below the bunded area to separate and collect any spilt oil from rainwater. 

The substation switching gear, insulators, circuit breakers and main transformers will be 

less than 7m in height. 

A boundary stock proof fence (approximately 1.2m high wire mesh) will be constructed 

around the perimeter of the substation site and an internal 2.3m high wire mesh security 

fence at a distance of 10m within the boundary fence. 

Drawing Sheet 84 in Appendix A (Appendix A7 Substation, Underground Cabling & 

Transmission Line Details) shows indicative layout details of the substation facilties 

together with the services building discussed below. 

3.2.12 66 kV Transmission Line Connection 

A multi span single line 66 kV overhead connection is proposed to connect the substation to 

the Mainpower 66kV Line, which runs adjacent to the western side of the project. The 

proposed transmission line is approximately 2.7km long and supported on 12 transmission 

line structures. The transmission line structures proposed are concrete double pole 

structures, known as Pi Poles, no greater than 22m high. Indicative details on the layout 

and the proposed structures are shown on Drawing Sheets 85 and 103 in Appendix A 

(Appendix A.7 Substation, Underground Cabling & Transmission Line Details). The 

majority of pole structures will be supported by guy wires to reduce the size of the pole 

foundations. We expect each pole foundation will comprise a bored hole approximately 

800mm in diameter and approximately 2 metres deep filled with concrete. It is likely the 

foundations supporting the guy wires will also be concrete filled bored holes. The total 

volume of concrete per pole structure is expected to be minimal at approximately 10m 3 . 

The potential effects of the proposed transmission line route and structures have been 

minimised by: 

• Reducing visual impact by avoiding ridgelines. 

• Avoiding constructing access roads to each transmission structure by locating the 

transmission structures near existing established farm tracks. 

• Reducing the number of structures by reducing the number of turn angles 

Within the substation a single gantry no greater than 20m high will provide the overhead 

link to the main 66kV transmission line. Photograph F24 in Appendix F shows a typical 

gantry structure (Project White Hill) similar to the one proposed for this project. It is 

important to note that the gantry structure shown in Photograph F24 is a double gantry 

whereas this project proposes a single gantry structure. 

3.2.13 Services Building 

A permanent services building, including car-parking, for post construction maintenance is 

required. The services building will house a workshop, control room (for managing 

turbines) and amenities. The dimensions of the services building are approximately 33m x 

11m. The services building will be single story portal frame structure with steel cladding. 

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The maximum height of the services building is 7m. The services building will be serviced 

for water, sewerage and stormwater as described above for the switchgear building. The 

Services building will also support some communication equipment for operation of the 

wind farm site. This equipment may include up to two communications dishes mounted on 

the side of the building. 

The services building will be serviced in the following manner: 

 

 

 

Water supply: It is likely the building will rely on a rainwater collection system with 

on-site storage tank or tanks, or use the local mains supply if authorised by the 

Hurunui District Council. 

Sewerage: Any foul water will be directed to a septic tank located within the site 

area. Foul water flows are expected to be minimal, being generated from a single 

toilet, washbasin and kitchen area. Flows are likely to be managed easily by the 

soakage field contained within the site. Prior to design a soakage test will be 

undertaken to confirm the size of soakage field required. 

Stormwater: Runoff is expected to be minimal given the intention to collect rainfall 

runoff. Excess rainwater will be directed on to land/adjacent undisturbed areas. 

3.2.14 Meteorological Masts (Wind Monitoring Towers) 

Two wind monitoring towers up to approximately 80m in height will be installed on the site 

to provide wind data for operational purposes. The proposed location of the wind monitoring 

masts are shown on Drawing Sheet 1 in Appendix A (Appendix A.1 Overall Site 

Development Plans). 

The wind tower is likely to comprise a steel truss structure on a concrete foundation pad of 

approximately 8.6m x 8.6m x 1m thick. Indicative wind monitoring tower details of a lattice 

tower is presented on Drawing Sheet 101 in Appendix A (Appendix A.9 Indicative Wind 

Monitoring Mast Details). Guyed towers may also be utilised. 

The position of the wind monitoring tower is determined by the location of the turbines and it 

may be necessary to reposition the wind monitoring tower within a 150m radius of the 

indicated placement area. 

Construction of the tower will require the preparation of a flat working platform of 

approximately 12m x 12m to accommodate a crane and other construction vehicles. The 

sites as indicated have been selected in view of their relatively gentle grades in order to 

minimise earthworks. Working platform preparation and rehabilitation is envisaged to be 

similar to that for turbine platforms (but minor in comparison) as described in Section 3.2.3 

above. 

3.2.15 Estimated Earthwork Volumes & Construction Footprint - Summary 

The pessimistic estimate of the all land disturbing activities within the core site is 

summarised in Table 14 below. 

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Land Disturbing Activity Cut (m 3 ) 

Footprint 

(m 2 ) 

Footprint/ 

Landholding 

Area (34km 2 ) 

Core Site Access Roads 435,000 

Turbine Platforms 225,000 

305,000 0.90% 

Substation & Services Building 16,000 5,000 0.01% 

Lay down Areas & Site Office 9,000 26,000 0.08% 

Trenching & New Tracks for Transmission Line 12,000 6,000 0.02% 

Borrow Areas 76,000 25,000 0.07% 

Spoil Fill Sites n/a 309,000 0.91% 

Erosion & Sediment Controls at Spoil Fill Sites n/a 15,000 0.04% 

Project Total 773,000 691,000 2.03% 

Table 14: Summary of Pessimistic Excavation Volumes within Core Site 

3.2.16 Construction Footprint in Relation to Hydrological Catchment Areas 

Drawing Sheet 22 in Appendix A (Appendix A.6 Hydrological Catchment Area Plan) 

identifies the various hydrological catchment areas which encompass the project area. This 

drawing illustrates the proportion of the project footprint to the catchment area and the 

remoteness of the project footprint to streams within each catchment area. Table 15, 

below, complements this drawing and shows: 

• Pessimistic earthworks cut volumes generated within each hydrological catchment 

area based on a pessimistic earthworks cut-to-waste volume of 683,000m 3 derived 

from Table 14. 

• Corresponding disposal fill areas from earthworks cut volumes within each 

hydrological catchment area based on an average fill site depth of 2.5m. 

• The construction area footprint within each hydrological catchment area. 

• The percentage of construction area to catchment area including the overall 

construction area to catchment area. 

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Hydrological 

Catchment 

Catchment 

Area (km 2 ) 

Cut-to-Waste 

(m 3 ) 

Disposal Fill 

Area (From 

Cut-to - 

Waste 

Material) 

(m 2 ) 


Area (Turbine 

Platform, 


Road & Other 

Footprint (m 2 ) 

Total 

Area (m 2 ) 

Total 

Area/Catch 

ment Area 

(%) 

1 (North) 6.16 72,000 40,000 39,000 79,000 1.28% 

2 (Tipapa) 3.79 107000 25,000 40,000 65,000 1.72% 

3 (Cave) 6.89 196,000 45,000 89,000 134,000 1.94% 

4 (Motunau 

East) 

5 (Motunau 

Upper) 

4.32 48000 28,000 21,000 49,000 1.13% 

12.11 210000 79,000 105,000 184,000 1.52% 

6 (West) 4.26 17000 28,000 9,000 37,000 0.87% 

7 (North 

West) 

9.96 123,000 65,000 78,000 143,000 1.44% 

Project Total 47.49 773,000 310,000 381,000 691,000 1.46% 

Table 15: Earthworks Volumes and Areas Summarised by Catchment Area 

Table 15 illustrates that the proportion of the total construction footprint area to hydrological 

catchment area is very minor and overall represents approximately just 1.34% of the total 

hydrological catchment area. However Table 15 also identifies that hydrological catchment 

area No.3 (Cave) has the highest proportion of construction footprint area to catchment 

area followed by No.2 (Tipapa) and No.5 (Motunau Upper). Where possible the 

construction footprint area has been redirected from the more ecologically sensitive areas 

such as Cave and Motunau Upper to the less sensitive northern catchment areas including 

Tipapa. At detailed design more refinement to the road alignments and turbine platforms 

should result in more of the construction area positioned in the less sensitive catchment 

areas. 

A large fill site is proposed at a saddle along Road D just north of Turbine D5. This site will 

be a combination of structural fill to form the core of Road D as well as spoil fill to form the 

batters. This fill straddles the northwest catchment area and the more sensitive Motunau 

Upper catchment. Specific controls at this fill site will be required to manage sediment 

particularly where sediment run-off is within the Motunau Upper catchment. 

Measures to avoid, remedy or mitigate the potential adverse effects from discharges, 

including sediment run-off are discussed in the next section and in Appendix E (draft 

Construction Environmental Management Plan). 

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3.2.17 Water Demands 

As discussed in section 3.2.6 a water supply will be required to supply any onsite concrete 

batching, together with other site construction activities including dust suppression, 

stabilization and re-vegetation, pavement construction and for any mobile crushing plant. 

Indicative estimates of potential water demand are summarised below in table 16. 

Activity 

Peak Daily 

Demand (m 3 ) 

Maximum 

Total Water 

Demand (m 3 ) 

Time Period 

Dust Suppression (non potable) 80 17,000 26 days per month for 8 months 

Stabilisation & Revegetation (non 

potable) 

15 3,100 26 days per month for 8 months 

Pavement Construction (non potable) 10 1,300 26 days per month for 5 months 

Mobile Crushing Plant (non potable) 5 1,000 26 days per month for 8 months 

Turbine Foundations & Other 

Concreting (potable) 

80 2,600 2 per week over 4 months 

Total 190 25,000 

Table 16: Indicative Estimates of Potential Water Demand 

Preliminary discussions with Hurunui District Council (HDC) suggest that a significant 

proportion of this demand may be met via supply from the HDC water mains. Water supply 

from the mains and permitted abstraction rates will need to be negotiated with HDC at the 

appropriate time, however it is envisaged that temporary water storage tanks would be 

established on site to enable the buildup of water storage volume. 

Any shortfall in water requirement can be met via tanker delivery from offsite, from the 

creation of temporary stock ponds, or by stream abstraction within any consented or 

permitted limits. 

3.3 Discharges 

3.3.1 Erosion, Sediment and Dust Control 

We recognise that the construction of this wind farm will require extensive earthworks. 

However, the potential impact from erosion, sediment run-off and dust emissions are likely 

to be minor given the environmental management measures that will be applied. Details on 

the environmental management measures are discussed in detail in Appendix E (draft 

Environmental Management Plan) while the impact from erosion, sediment run-off and dust 

emission is addressed in the Ecological Values and Assessment of Effects report prepared 

by Boffa Miskell. One of Meridian’s prime objectives for the construction of this wind farm is 

to ensure that any potential adverse effects on the environment from any erosion, or 

sediment and dust discharges are avoided, remedied or mitigated. To achieve this 

Meridian will: 

 

Ensure that environmental management is a core requirement in the management 

process. 

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Prepare and implement a robust EMP and site specific SEMPs. 

Ensure a partnership approach between Meridian and the contractor(s). 

Ensure adequate resourcing of environmental management activities. 

Monitor and audit the project works to determine the effectiveness of the 

environmental management activities being undertaken. 

Ensure all incidents are reported to the Project Environmental Manager. 

The following outlines the approach that Meridian will implement to mitigate the impact of 

construction activities on the environment. 

a) Contract Requirements 

Although Meridian will be ultimately responsible for ensuring EMP and consent condition 

compliance, the construction contract will place specific responsibilities on the contractor for 

environmental management. The contract will require the contractor to: 

 

 

 

 

 

 

 

Comply with the Environmental Management Plan (EMP) and Supplementary 

Environmental Management Plans (SEMPs). Refer to Appendix E for details on the 

EMP and SEMPs process. 

Have read and comply with resource consent conditions. 

Take all necessary measures to ensure no adverse effects arise from dust 

discharges. 

Attend environmental compliance meetings. 

Ensure all plant and equipment is clean and well maintained. 

Foster an environmentally responsible attitude on behalf of the contractor and his 

employees. 

Follow Meridian’s Accidental Discovery Protocol for archaeological or cultural 

remains. 

b) Erosion, Sediment and Dust Control Plans 

The main tool for avoiding or mitigating potential adverse effects from erosion, sediment 

and dust discharges is by preparing and implementing SEMPs for each major component of 

the work. There are four steps in preparing and implementing each SEMP: 

Plan Preparation 

Separate SEMPs will be prepared for specific locations and activities (as outlined in the 

EMP). To get construction underway as soon as possible, plans for partial sections of 

works may be prepared. 

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The first stage in plan preparation will be a walk over of the area to be covered by the plan. 

The walk over will involve the contractor, Meridian’s Construction Manager, Meridian’s 

Engineer, Meridian’s Environmental Manager, and an Environment Canterbury 

representative/s and Hurunui District Council representative/s (for some components). The 

purpose of the walk over is to identify the measures needed for minimising erosion and 

sediment generation, e.g. cut off drains and treatment options for storm water runoff such 

as silt ponds, grit traps and so on. Based upon these discussions a draft SEMP will be 

prepared by the contractor assisted by Meridian’s Environmental Manager. 

The SEMP will include the following: 

 

 

 

 

A method statement covering health and safety matters, construction method, 

monitoring and contingencies. 

A plan or series of plans showing spoil areas to be used, cut off drains, culverts, 

surface water control works, silt ponds and any other sediment control measures. 

Inspection and reporting schedule particularly in response to adverse weather 

conditions. 

A list of maintenance activities. 

In addition, the SEMP will cover revegetation requirements, storage and handling of fuel, 

and management of waste. 

There are five location specific SEMP areas proposed for this project. At this stage an 

indicative SEMP plan for one of these areas has been prepared demonstrating the intended 

approach for such plans. Details on the SEMP area boundaries and the indicative SEMP 

plan are provided in Appendix E. 

Review 

The draft SEMPs will be submitted to both Environment Canterbury and Hurunui District 

Council as well as Meridian's Engineer and Environmental Manager for review. Comments 

from the review will be provided to the contractor who will finalise the plan. The final plan 

will be provided to the regional and district councils for their information and to satisfy any 

resource consent requirements. 

Implementation & Monitoring 

Implementing the SEMPs will be the responsibility of the contractor. Where required the cut 

off drains, silt ponds and other similar works will be installed in advance of earthworks 

commencing. 

The construction works will be monitored on a regular basis by Meridian or Meridian’s 

advisors. The frequency of this monitoring will be dictated by the work programme. A 

summary of the inspection will be copied to Meridian's Engineer. Work will only commence 

once Meridian’s Construction Manager is satisfied that appropriate measures to avoid 

potential adverse effects are in place or planned to be implemented. Examples of erosion 

and sediment control measures proposed for this project are detailed in the draft EMP in 

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Appendix E. Erosion and sediment controls will be designed and installed in accordance 

with Environment Canterbury's Erosion and Sediment Control Guidelines (2007). 

Auditing 

Ensuring an audit of compliance with the SEMPs will be the responsibility of Meridian’s 

Environmental Manager. It is proposed the audit will involve an inspection of site works and 

a meeting that involves the contractor, Meridian’s Construction Manager and Environmental 

Manager. Environment Canterbury and Hurunui District Council will be invited to be part of 

this audit process. 

A programme for the audit meetings will be set once the construction programme is known. 

Any recommendations resulting from the audit process will be recorded and used to modify 

the current and subsequent SEMPs. 

(c) Reporting 

Initially, a weekly report shall be prepared by the contractor to identify the erosion, sediment 

and dust control activities undertaken, to provide comment on their effectiveness, and to 

identify any improvements which are required. This report will be reviewed by Meridian's 

Engineer. The reporting timetable will be reviewed on an ongoing basis as the project 

progresses. 

3.3.2 Permanent Stormwater Run-off 

Access roads 

Stormwater runoff control through cut sections of road will consist of unlined open side 

drains at the base of each cut. Depending on the ground conditions at any steep sections 

of access road, there may be a need to incorporate short lengths of concrete lining to limit 

erosion. On steeper sections, it is envisaged that stormwater flow velocity will be controlled 

(to minimise scour) with the use of rip-rap dissipaters or other similar devices. 

Water from the side drains will be discharged by either 300mm (approximately) diameter 

culverts under the access roads and fluming to gullies, or by fluming direct to gullies as 

appropriate. Given that the access roads are generally located at the upper reaches of 

catchment areas, water from most side drains will be discharged on to land in dry gullies. 

However, where existing streams are present, such as that indicated by existing culverts, 

water will be discharged into the stream. 

Riprap or other similar stabilisation measures will be utilised at points of discharge. The 

position and intervals of the culverts will be determined during detailed design. The aim is 

to retain run-off within the existing natural catchment area. 

Turbine platforms 

Given the general nature of platform areas (e.g. small areas at the top of catchments), no 

particular permanent stormwater drainage measures are envisaged other than ensuring 

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that platform areas around the basecourse hardstand areas are backfilled with top soil with 

a slight cross fall, and regrassed to avoid erosion. 

Drainage provision may be provided to the foundation excavation by way of a trench or filter 

drain with suitable stabilised outlet. 

Fill sites and lay down areas 

The proposed treatment for fill sites is discussed in Section 2.4. Finished ground profiles 

will be shaped to ensure that natural drainage paths are maintained. On completion of 

construction, these sites will be re-topsoiled (with material which has been removed and 

stockpiled) and re-vegetated as appropriate with runoff direct onto grassed land on 

surrounding catchments. 

Lay down areas will have a general crossfall, allowing stormwater run off in the direction of 

the general slope of the land. Sedimentation and erosion control measures as described in 

Section 3.3.1 above will be applied. On completion of construction, lay down areas will be 

rehabilitated in the same manner as fill sites. 

3.3.3 New Culverts at Stream or Gully Crossings in the Core Site 

No stream crossings have been identified within the core site however there are locations 

where upper gully crossings and existing open channel drain crossings will require culverts. 

Table 15 below summarises the proposed culverts identified along core site access roads. 

Culvert sizes have been based on flows for flood return periods of 20 years with provision 

for secondary flow paths across purposely lowered sections of the access road (for 

overtopping for longer return periods). 

We envisage no gully crossings in addition to those tabulated given the layout of the access 

roads are generally close to or on ridge tops where the terrain is relatively gentle. However, 

where new culverts are required per the detailed design (consequent to adjusting the 

turbine platforms and access roads within a 100m radius placement area), culverts will be 

sized as described above. 

The approximate height of the embankment at the culvert inlet of the majority of all culverts 

is less than 1m apart from one culvert on Road D which has an embankment height of 

approximately 1.5m at the culvert inlet. Given the embankment heights at culvert inlets are 

not significant no locations have been identified where an embankment fill could essentially 

form a ‘dam’ across upper valleys. However, if a significant embankment fill arises 

consequent to adjusting the turbine platforms and access roads (within a 100m radius 

placement area) the culvert will be sized on flows for flood return periods of 100 years to 

address the effects of ‘heading up’ associated with culverts with significant embankment 

fills. 

Based on this design criteria, the required culvert sizes are indicated in the following table. 

The final size of the culvert, where required, will be determined during the detailed design 

stage. This table also identifies a range of characteristics associated with each culvert. 

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An ecological assessment of these locations is discussed in the Ecological Values and 

Assessment of Effects report prepared by Boffa Miskell. 

Road 

Culvert 

ID 

Indicative 

Culvert Size 

(mm dia.) 

Indicative 

Culvert 

Length (m) 

Approx 

Catchment 

Area (Ha) 

Approx Height of 

Embankment at 

Inlet (m) 

(from ground 

level) 

Northern A1A 375 15 4 ≤1.0 

Access Road A1B 375 14 4 ≤1.0 

Road A A1 300 15 1.2 ≤1.0 

A2 450 14 3.0 ≤1.0 

A3 600 13 3.8 ≤1.0 

A4 300 11 0.7 ≤1.0 

A5 300 11 0.5 ≤1.0 

Road B B1 375 13 2.1 ≤1.0 

Road D D1 300 20 1.1 1.5 

D2 300 18 0.3 ≤1.0 

D3 300 20 0.7 ≤1.0 

Road G G1 600 14 4.4 ≤1.0 

Table 17: Culverts at Gully Crossings within the Core Site 

The culvert location plan is shown on Drawing Sheets 23 to 26 while typical culvert details 

are shown on Sheet 27 in Appendix A (Appendix A.4 Culvert Location Plans & Typical 

Details). 

3.3.4 Upgrading Existing Culverts Along Motunau Beach Road 

One culvert along Motunau Beach Road, just south of the proposed site entrance, will 

require lengthening to accommodate the proposed widening of the road shoulder along this 

section. The existing 450 diameter concrete culvert, which serves an open channel drain 

from within the Batchelor/Daly property will require lengthening on the eastern side of 

Motunau Beach Road as shown on Drawing Sheet 205 in Appendix A8. 

3.3.5 Culvert Construction Methodology 

Installing culverts will involve bed preparation, laying of pipe culverts, construction of 

headwalls and backfilling/compaction. There are no stream crossings therefore stream 

diversions will not be required. 

4 Minor Shoulder Widening At Motunau Beach Road 

4.1 Shoulder Road Widening Opposite Site Entrance 

Directly opposite the proposed site entrance the shoulder of the southbound lane will be 

widened approximately 3m to provide an overall sealed width of approximately 6m from the 

centerline as shown on Drawing Sheet 205 in Appendix A8. The widening is provided to 

facilitate vehicles turning right into the site from the south. The proposed widening will 

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extend over an existing road culvert which will need to be lengthened as described in 

Section 3.3.4 above. 

The existing permanent stormwater network of side drains will be maintained on the eastern 

side of Motunau Beach Road by forming a new side drain at the toe of the proposed 

widened section. This side drain will also discharge into the existing open channel drain just 

east of Motunau Beach Road. On the western side the existing side drain will follow a new 

side drain formed at the site entrance and will discharge into the existing open channel 

drain in the Batchelor/Daly property. 

The widened area will be formed with minor quantities of compacted basecourse and 

sealed with chipseal or harder wearing asphaltic concrete surfacing to match the existing 

surfacing. 

5 Geotechnical Assessment 

5.1 Geotechnical Appraisal 

A preliminary geotechnical appraisal of the site was completed in 23 August 2009 and is 

presented in Appendix D. This appraisal primarily examined the seismic risk of the site and 

the potential slope instability along access roads and at turbine locations. Seismic risk and 

potential instability are discussed below. 

5.2 Geotechnical Risk 

5.2.1 Potential Slope Instability 

Slopes observed in the preliminary geotechnical appraisal visits were considered to be 

stable. The site reconnaissance did not identify any areas of deep-seated instability in the 

areas proposed for use as access roads or turbine sites. Shallow seated slides (up to 1.0m 

deep) and creep-type failures within the overburden material on slopes were observed at 

localised areas throughout the site but restricted to slopes over 28 degrees. Turbine sites 

and access roads are setback from steep slopes, generally located on ridge tops (where 

the overburden is relatively thin). Construction activities will be outside the areas of shallow 

seated slides and creep-type failures and therefore unlikely to be affected by any slope 

instability. 

Where road cuttings are close to, or down slope of turbine foundations, roads are 

positioned so that cuttings are adequately set back from the base of the foundations. This 

is to reduce the risk of undermining turbine foundations. Access routes have been chosen 

to follow existing tracks, ridge lines and to generally avoid steep slopes (slopes equal to, or 

greater than 28 degrees in the project area) to minimise the potential for creating instability 

due to slope undercutting. Avoiding areas with steep side slopes also serves to minimise 

the height of cuts, and therefore maximise stability. Drawing Sheet 10 in Appendix A 

(Appendix A.2 Access Road Plans & Cross Sections) shows the typical cross slopes along 

each road length. In addition, Figure 4 in Appendix D demonstrates that all turbine 

platforms and the vast majority of all access roads avoid slopes equal to, or greater than 28 

degrees. However any access roads which run through these areas will typically be 

5C-1604.02 

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assigned an acceptable risk profile of “low” at the detailed design stage and special 

measures taken to reduce the risk of instability. Therefore the construction effects of this 

project on shallow seated instability will be no more than minor. 

Siting the turbine foundations will involve detailed geotechnical investigation of each 

platform to refine each turbine’s position and setback from any adjacent slopes. Such siting 

will ensure there is a very low risk for any natural slope instability to undermine a turbine 

foundation. For road cuttings geotechnical investigation will ensure global stability of 

cuttings through appropriate batter design. Some small localised material loss from the 

face can be tolerated given the low accessibility of the roads beyond the construction 

period. 

Existing farm access tracks were typically at grade, with some generally low height (1.0 – 

1.5 m) cuts. In general the low height cuts stand at close to vertical. Deeper existing road 

cuts range in height between approximately 3.0m to 4.5m high at slope angles 

approximately 63 degrees (1H:2V). The bedrock was observed to be stable at these slope 

angles up to heights of about 8m. No obvious rock failures were observed in existing cuts. 

Photograph 6 in Appendix B shows a cut slope on an existing track ranging up to 

approximately 4m to 5m cut height. 

In view of such observations of the site, the process proposed, and based on knowledge of 

proposed road and turbine positioning, the risk of landslides, or large scale soil movement 

being mobilised by the proposed works is considered low. This preliminary assessment of 

slope failure risk is also affirmed by the generally shallow depth of surficial soils overlying 

the more stable (barring bedding planes) bedrock. Final cut batter angles, or requirements 

for benching will be adjusted as necessary during detailed design to suit any geotechnical 

recommendations. 

Local bearing capacity can affect the feasibility of turbine sites in some situations. Since 

these turbines are typically located on ridge tops where the bedrock is relatively shallow, 

bearing capacity of the soil/rock is unlikely to constrain turbine positioning. 

Detailed geotechnical investigations at the detail design stage and on-site assessment 

during construction will be undertaken to confirm the above preliminary conclusions and to 

establish appropriate cut slopes around the road network. We recognise that some 

ongoing maintenance of steeper cut slopes may be necessary during the life of the wind 

farm. 

5.2.2 Seismic Hazard 

With reference to the preliminary geotechnical appraisal in Appendix D, the seismicity of the 

site is governed by the presence of the following faults: 

• Omihi Fault (borders the northwest of the site) 

• Kaiwara Fault (5 km to the north of the site) 

• Hurunui Bluff Fault (15 km to the northwest of the site) 

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• Hope Fault (45 km to the north of the site) 

• The southern Alpine Fault (95 km northwest of the site) 

• Pegasus Bay Fault (an offshore fault, which lies approximately 30km to the 

southeast of the site) 

Other minor faults are mapped within the wind farm area, some of which may be active. 

Fault Rupture 

Based on geological evidence, the recurrence interval for the Omihi and Kaiwara Fault is 

2000 to 5000 years, having last ruptured more than 10,000 years ago. The southern Alpine 

Fault has a recurrence interval of 500 years and evidence suggests it last ruptured between 

340 and 410 years ago. The Hope Fault is considered to have the shortest recurrence 

interval of 120 years, with the last rupture 121 years ago. Records of the Hope fault 

earthquake indicate magnitudes greater than 7. 

An interim guideline to assist resource management planners in New Zealand “Planning for 

Development of Land on or Close to Active Faults”, Ministry for the Environment, 2003 

defines the fault avoidance zone as a zone that extends 20m on either side of the active 

fault line, shown on a plan as an active fault trace. The guideline requires that structures 

with special post disaster functions (Building Importance Category 4 structures) are not built 

in the fault avoidance zone. For this project, all turbines will be located at distances 

substantially larger than 20m from active faults and therefore are not expected to be 

adversely affected by rupture of the known faults. In addition to separation from fault 

zones, wind loading and operational fatigue dominate the foundation design for the 

turbines. Therefore, the risk of damage to wind turbines associated with fault rupture is 

assessed to be low. Roads and cables crossing the fault rupture zones would be affected, 

but these can be readily repaired and reinstated following such an event. 

Ground Shaking 

Wind turbines are designed to withstand the large wind forces imposed by extreme wind 

storms that may occur during the life of the turbines. Therefore the turbines have a large 

reserve of strength available to resist the forces imposed by earthquake ground shaking, 

including shaking resulting from rupture of any of the faults listed above. 

Liquefaction 

There is no possibility that the ground beneath the turbine foundations will liquefy under 

earthquake as they will be founded on rock. 

Earthquake Induced Slope Failures 

Earthquake-induced failures (in the form of debris flow and slips) can be expected in the 

weaker overburden materials, but such failures would not affect the wind turbine 

foundations, as all the wind turbines will be founded on the bedrock, or set back from slope 

edges. 

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6 Other Proposed Activities 

6.1 Detailed Geotechnical Investigations 

As part of the detailed design investigations there will be a need to undertake more 

comprehensive site investigations and testing to determine site specific geotechnical design 

parameters for road and turbine platforms as well as turbine foundations. Types of intrusive 

testing that are likely to be employed include: 

• Trial pits and borehole investigations in the vicinity of potential borrow areas, large 

cuts, embankments, the substation location and at turbine sites. 

• Borehole and possible rock anchor pullout tests to confirm detail design 

assumptions for turbine foundations. 

• Trial pits to test the suitability of material for thermal bedding / backfill for 

transmission cables 

6.2 Controlled Blasting 

Based on visual inspection of the site, together with the preliminary geotechnical appraisal, 

excavation is most likely to be achieved by the use of hydraulic excavators, large bulldozers 

with ripping attachments, and motor scrapers. 

In the event that harder material (particularly moderately/slightly weathered or intact rock) is 

encountered it may be necessary to utilise controlled blasting operations to achieve 

economic working rates. 

If employed, it is anticipated that small amounts of explosives will be used to break up rock 

masses into more manageable pieces. Rock drilling to plant the explosives will also be 

required. Management measures and methodologies for controlled blasting operations will 

be documented in the contractor’s management plan in advance of any work commencing. 

This will set out management measures, OSH requirements, blast design, methods, site 

protocols, storage requirements, warning systems, and noise monitoring requirements as 

required under current HSNO Regulations. 

7 Indicative Construction Methodology, Noise and Lighting 

7.1 Indicative Construction Methodology 

The project implementation timeframe, based on experience from other wind farm projects 

(Te Apiti, White Hill and West Wind) is likely to be in the order of 18 months depending on 

the sequencing adopted and weather conditions. 

The initial construction priorities are likely to focus on civil earthworks for the key access 

route (Northern Access Road), platforms and the substation. Following on from the initial 

construction phase the construction priorities are likely to focus on turbine foundation 

construction and erection as well as civil earthworks on the remaining access roads 

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sequenced over the project implementation timeframe. The likely sequence of construction 

for the site is: 

• Site mobilisation including establishment of temporary site offices, workshops, 

stores and other facilities. 

• Installing erosion & sedimentation control measures. 

• Upgrading key access routes to core site. 

• Preparing initial fill sites and haulage routes. Haulage routes will typically follow the 

proposed access routes and existing access tracks, as appropriate. 

• Excavating and forming access roads with any surplus cut material transported, 

placed and compacted at fill sites. 

• Upgrading existing and constructing new culverts. 

• Preparing lay down areas and substation platform. 

• Constructing the substation. 

• Constructing the overhead transmission line from the substation to existing external 

66kV transmission line. 

• Constructing cranage and turbine platforms. 

• Progressive excavation and construction of reinforced concrete turbine foundations, 

as platforms become available. 

• Cut/fill slope and fill site rehabilitation (this will be undertaken on a progressive 

basis). 

• Progressively installing internal transmission network (cables) typically along the line 

of formed access roads, or across country as appropriate. 

• Progressively delivering turbine towers and generators. 

• Progressively installing and commissioning (turbines and substation). 

• Removing temporary services and site offices, rehabilitating lay down areas and 

general site reinstatement. 

Figure 4 below shows an indicative project implementation timeline, with broad construction 

activities, over an 18 month period. A more detailed programme will be developed by the 

Meridian Implementation Team prior to construction. 

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Construction Activity 

Construction Period (Months) 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 

Site Establishment/Civil Mobilisation 

Civil Earthworks/Roading 

Concrete Batching 

Substation & O/H Transmission 


Turbine Foundation Construction & 

Turbine Installation 

Turbine Commissioning 

Site Rehabilitation 

End Project 

Figure 4: Indicative Construction Timeline 

7.2 Construction Noise 

Typical plant likely to be employed for the construction work may include: 

• Hydraulic excavators. 

• Scrapers and dumpers. 

• Bulldozers (with ripping attachments). 

• Mobile crushers for processing basecourse. 

• Main and assistant turbine erection cranes Graders and rollers. 

• On-site batching plant with concrete mixer trucks. 

• Portable generators. 

• Drilling rigs for detailed geotechnical investigations, possible installation of rock 

anchors and testing. 

Construction noise may also result from blasting if employed. 

Construction works will require a noise management plan in accordance with NZS 

6803:1999 to manage noise emissions from construction activities involving the above 

types of plant and activities. Potential noise impacts are assessed and discussed in the 

Project Hurunui Acoustic Assessment report by URS. 

7.3 Lighting and Night Works 

Certain works may take place at night (outside regular working hours). In this respect, it is 

envisaged that work may progress on a 24 hour basis for turbine sites and access roads 

remote from any dwellings while complying with the recommended noise limits at any 

neighbouring dwellings. 

Where works after sunset or night works are permissible, portable lighting rigs will be 

employed. 

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7.4 On Site Project Office 

The location of the main project site office including stores and initial lay down area is 

proposed in the front paddock of the Batchelor/Daly property adjacent to the initial section 

of the Northern Access Road. The layout of any other temporary site offices, workshops, 

stores and other construction facilities, such as the concrete batching plant, will be 

determined following further detailed investigations of the construction and installation 

strategy. 

One security gatehouse will be located just in from the Northern Access Road, off Motunau 

Beach Road, to control access in and out of the site. 

An indicative main site office layout is shown on Drawing Sheet 203 in Appendix A 

(Appendix A.8 Indicative Site Office & Lay-down Area Plan). This drawing shows the 

indicative dimensions and layout of the proposed structures which make up the temporary 

site office facilities. In general the site office structures will comprise single storey sandwich 

panel prefabricated structures with a combined area of approximately 380m 2 . These 

structures are typically 2.8m high (not including the footings) and come in two standard 

colours, green and white. Allowance has been made for a communication mast 

(approximately 6m high), diesel generator and diesel fuel tank. The diesel generator and 

fuel tank will be located in a bunded area to retain any fuel leakage. Sewerage and waste 

water will be directed to a holding tank and removed off site. At completion of the 

construction phase these temporary buildings will be removed off site. 

7.5 Bulk Fuel Storage Facility 

A bulk storage facility will be located at or near the site offices or close to the active 

construction area. The bulk storage facility will provide fuel to specialist mini tankers that 

will service all vehicles on site. In special circumstances where mini tanker access is not 

possible, a towable tanker will be used to service the vehicles. This facility is discussed in 

more detail in the EMP in Appendix E of this report. 

7.6 On Site Batching Plant 

The contractor will require a concrete batching plant to minimise the number of truck trips 

on the public road network and increase efficiency. Photograph F25 in Appendix F shows 

the concrete batching plant established at Project West Wind. This photograph illustrates 

an indicative layout and the structures which comprise a typical concrete batching plant 

proposed for this project. 

The likely structures and facilities which comprise a typical concrete batching plant 

including indicative dimensions are: 

• Control room and storage building (6m long, 2.8m high, 2.4m wide). 

• Prefabricated office and amenities structure (4.8m long, 2.8m high, 3m wide). 

• Mobile batching plant unit which includes, but is not limited to, hoppers, aggregate 

storage bins, compressor, cement silos and conveyors (18m long, 4m wide, 7m high 

(highest point)). 

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• Water tank. 

• Aggregate stockpile area (50m x 20m). 

• Truck washdown area. 

A concrete batching plant occupies a relatively small area for a relatively short duration 

(approximately 5 months) of the construction period as the plant is only on site during the 

foundation construction stage of the construction programme. The concrete batching 

process proposed under this application is a dry batching process which involves mixing 

dry materials in the batching plant. The dry material is then transferred into a normal 

concrete mixing truck and only then is water added. Minor dust discharges potentially arise 

from the transfer of materials into the plant and again, into the mixing truck. It is envisaged 

that measures to contain any dust will be outlined in the EMP or relevant SEMP. Such 

measures are likely to include cement storage within a silo and aggregate storage bins. 

Given that the concrete is mixed in the truck, rather than in the batching plant, the wash 

down requirements associated with conventional concrete batching plants are significantly 

reduced. The dry batching process ensures that there are no requirements to wash down 

wet concrete within the batching plant. Measures to contain any dry cement spillage in the 

event of a batching plant failure will be outlined in the EMP or relevant SEMP. Such 

measures are likely to include a temporary concrete slab beneath the loading area and 

containment bunding around the plant incorporating a 2 stage settling pond or sediment 

control pond. The concrete batching plant will not be located within 100m of any 

permanent watercourse. 

On completion of the works the site office areas and batching plant areas will be stripped of 

any basecourse, re-topsoiled (with material which has been removed and stockpiled) and 

ground cover replanted as appropriate. 

8 Summary and Conclusions 

Construction of the civil works elements for Project Hurunui Wind will require excavation; fill 

site creation; potential on-site extraction; potential crushing and processing of basecourse 

pavement materials; construction of culverts; substation and transmission line construction; 

internal site cable trenching and placement; concreting works and site regeneration. 

The key measure we have proposed to minimise the overall environmental effect of 

construction is to adopt the general design philosophy of following existing tracks and tops 

of ridges wherever possible. Following this general design philosophy will typically 

• Minimise the volume of excavation. 

• Avoid gullies & undisturbed watercourses. 

• Improve geotechnical aspects. 

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This report has demonstrated that potential effects within the site resulting from 

construction activities typically include: 

• Site stability issues. 

• Discharges to land and water from sediment run-off. 

• Stormwater discharges. 

• Flooding within the catchments affected by road embankments incorporating 

culverts. 

• Visual effects. 

• Local traffic effects. 

• Dust & noise nuisance. 

The potential effects and measures proposed to avoid, remedy or mitigate these effects are 

summarised as follows: 

Potential Effects 

Land disturbance 

at the recently 

covenanted QEII 

within the Turnbull 

property and the 

totara forest 

remnant within the 

Batchelor/Daly 

property 

Site Stability of 

Roads, Turbine 

Platforms, 

Substation, 

Transmission and 

Met Masts 

Site Stability of 

Disposal Fill Sites 

Measures to Avoid, Remedy 

or Mitigate Effects 

Avoid construction works within 

these areas. 

Avoid large slips and steep 

slopes. 

Avoid sidling fill situations on 

steep cross slopes. 

Avoid access roads undercutting 

turbine platforms. 

Ensure detailed geotechnical 

investigations are carried out at 

detailed design. 

Avoid steep areas. 

Select sites to suit depressions, 

Comments 

These two areas are recognised as having 

significant natural features. However these 

areas are outside the construction 

footprint. 

Natural slopes and existing cuttings in the 

project area are generally observed to be 

stable. In this respect the risk of 

landslides or large scale soil movement is 

considered low. 

Damp (soft) ground is not expected to be 

an issue as turbines and roads have been 

placed to avoid these areas. 

Road, Turbine & Substation Platforms 

Typical cut slopes to form roads and 

platforms are not typically expected to 

exceed 6m in height. Extreme cut heights 

of between 6m and 18m account only for 

approximately 7% of the total road length 

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or tops of natural gentle sided 

small or shallow valleys with 

good containment. 

Key and compact fill into 

surrounding land. 

Install subsoil drainage. 

in the core site area (24km). Based on 

materials observed on site, cut slopes of 

1H:4V are expected to be stable up to 

1.5m in height and cut slopes of 1H:2V are 

expected to be stable up to 5m in height 

and stable beyond this provided benching 

is employed at 5m intervals. 

Further geotechnical investigation and 

observation will be completed during 

detailed design to confirm design 

parameters. 

Site Stability – 

Seismic Risk 

Locate wind farm site away from 

major active faults. 

Disposal Fill Sites 

Fill site selection and design will follow a 

structured approach, as suggested in this 

report and will take place under the 

framework of the Environmental 

Management Plan (EMP) and 

Supplementary 

Environmental 

Management Plan (SEMPs). There is 

sufficient fill site capacity to accommodate 

the pessimistic earthworks cut volume. 

Overhead Transmission to 66kV Main 

The construction effects of the connection 

to the 66kV Mainpower Line on 

undisturbed land are expected to be minor 

and will remain within proposed 

transmission line construction envelope. 

Internal 33/22 kV cable reticulation 

Apart from one overhead section all 

33/22kV cables are expected to be 

installed under the access roads. As 

trenching works are typically undertaken 

within the road corridor, underground 

cabling is not expected to cause any 

additional land disturbance. 

Given the active faults are outside the 

wind farm area, no structural or foundation 

failure is expected in relation to rupture of 

any of the faults 

Discharges 

Land & Water 

to 

Staged construction. 

Revegetation and site 

A layer of basecourse will be provided to 

roads and platforms during construction. 

At steeper road sections, a sealed 

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rehabilitation throughout the 

construction phase. 

Environmental Management 

Plans to control erosion and 

treat sediment run-off. 

pavement may be provided. This will 

provide a clean running/working surface 

as well as minimise erosion. 

Turbine platforms will be rehabilitated upto 

the edge of basecourse hardstand areas 

with appropriate ground cover after 

construction. 

Sediment Run-off 

Discharges to the 

Cave and Motunau 

Catchment Areas 

Avoid where possible by 

redirecting works and/or 

discharges from sediment 

control structures to northern 

(including Tipapa) catchments 

assessed as having lower 

comparable ecological values. 

Ensure specific erosion and 

sediment controls at fill site just 

north of Turbine D5, in particular 

Some potential fill areas and lay down 

areas will involve the removal of existing 

topsoil and vegetation. The measures 

outlined in this report will ensure that these 

fill sites and lay down areas are blended 

back into the existing environment 

following their rehabilitation. 

In the likely event that an on-site batching 

plant is deployed, an SEMP will be 

developed to outline measures to manage 

any dust, sediment, cement and wash 

water discharges. Such measures are 

likely to include cement storage within a 

silo, aggregate storage bins, a temporary 

concrete slab beneath the loading area 

and containment bunding around the 

plant. 

Appropriate substation design such as 

bunding and interceptor tanks will ensure, 

in the unlikely event of transformer oil 

spillage, that the risk of oil discharge is 

low. 

Sewerage and waste water from the 

services building will be directed to a 

septic tank. Flows are expected to be low. 

In areas where the construction works 

border catchments, road alignments and 

fill sites can be adjusted to remain within 

catchments with lower comparable 

ecological values. 

The draft SEMP details specific measures 

at this area. 

5C-1604.02 

February 2011 56


Flooding 

Catchments 

Affected 

Culverts 

Within 

by 

where run-off is directed within 

the Motunau Upper catchment. 

Provide for overflows. 

Select road alignments which 

minimize catchment areas. 

Stormwater 

Discharges From 

Roads and Turbine 

Platforms 

Visual Effects of 

Roads, Disposal 

Fill Sites & 

Substation 

Provide permanent stormwater 

runoff management. 

Provide unlined open side 

drains, sumps, culverts & 

flumes. 

Direct discharges to land or 

adjacent undisturbed areas. 

Retain runoff within each 

existing natural catchment area. 

Select fill sites in areas “internal” 

to the site. 

Select substation site in low 

lying areas internal to the site. 

Utilise internal access roads and 

farm tracks as much as 

possible. 

Select alignments of new roads 

and platforms to be visible 

internal to the site as much as 

possible. 

Appropriate roadside drainage design 

employing measures such as fluming and 

riprap will reduce the risk of scouring and 

erosion. Roadside drains will generally 

discharge on to land. However, roadside 

drains may discharge into existing streams 

(ephemeral or otherwise) if located 

nearby. 

Measures as described in this report to 

mitigate stormwater run-off from turbine 

platforms, fill sites and lay down areas will 

ensure that natural drainage paths are 

maintained and erosion minimised. As 

platforms will be graded to the fall of the 

land, runoff will generally discharge 

directly into undisturbed land. 

As most new roads are close to or on 

ridge tops, new roads generally do not 

cross any streams or dam gullies. Where 

natural flow paths are affected by new 

roads, appropriate cross culverts will be 

provided to ensure that drainage paths are 

maintained. 

Some potential fill areas and lay down 

areas will involve the removal of existing 

topsoil and vegetation. The measures 

outlined in this report will ensure that these 

fill sites and lay down areas are blended 

back into the existing environment 

following their rehabilitation. 

5C-1604.02 

February 2011 57


Avoid rocky outcrops, significant 

natural features and areas of 

higher ecological value 

Local Traffic 

Effects of 


Works 

Reduce truck trips by exploring 

potential to source on site 

materials for roading 

basecourse. 

Reduce truck trips by utilising on 

site concrete batching plant. 

Dust & Noise 

Nuisance 

Adopt environmental control 

measures under the framework 

of the Environmental 

Management Plan (EMP) and 

Supplementary Environmental 

Management Plans (SEMPs). 

Appropriate requirements will be 

incorporated into the construction works 

documents to manage noise emissions 

from construction activities, including, but 

not limited to, preparation of a noise 

management plan in accordance with NZS 

6803:1999 to manage emissions from 

construction activities. 

We recognise that works to create Project Hurunui Wind will result in visible cuttings, soil 

disturbance, vegetation clearance as well as associated discharges to land and water. 

However, most of the construction effects are short term as opposed to long term, and 

potentially adverse effects resulting from such construction effects can be mitigated by the 

approach to design/construction and application of measures identified in this report. 

. 

5C-1604.02 

February 2011 58

Project Hurunui Wind Construction and Project Overview

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