M4687 20130503 Route Corridor Report

North Wales Wind Farm ConnectionsRoute Corridor Report

May 2013

Route Corridor Report 43

ContentsSection 1.0 Introduction

Section 2.0 Approach & Routeing Principals

Section 3.0 Overview of Routeing Methodology

Section 4.0 Application of Routeing Methodology

Section 5.0 Findings of Corridor Appraisal

Section 6.0 Conclusion

Figures:Figure 1.1 Wind Farm Development

Figure 1.2 Connection Types: Double Wood Poles, Steel Tower, Undergrounding

Figure 4.1 Project Study Area

Figure 4.2 Highest Environmental Value

Figure 4.3 Technical Constraints

Figure 4.4 Landscape Sensitivity (LANDMAP)

Figure 4.5 Broad Route Corridors

Figure 4.6 Biodiversity and Geology

Figure 4.7 Landscape and Visual Resources

Figure 4.8 Field Based Landscape Sensitivity

Figure 4.9 Historic Environment

Figure 4.10 Residential Amenity

Figure 4.11 Flood Risk

Figure 4.12 Forestry and Woodland

Appendices:Appendix 1: The Holford Rules

Appendix 2: Visibility Appraisal

Appendix 3: Corridor Appraisal Tables

North Wales Wind Farms Connection

Figure 01 - Wind Farm Development

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Moel maelogen

BrenigClocaenog

Myndd Mynyllod

St Asaph Substation

Llys Dymper

Nant Bach

Gorsedd Bran

Derwedd Bach

Foel Goch

Tir Mostyn

Wern Ddu

Braich Ddu

St Asaph Substation!(!(

County Boundary

Existing Wind Farm!(Possible Wind Farm requiring SP Connection!(

Key:Study Area

TAN8 Strategic Renewables Energy Areas

Proposed Wind Farm Substation

400kV Overhead Lines132kV Overhead Lines33kV Overhead Lines

Distribution Network

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Moel maelogen

BrenigClocaenog

Myndd Mynyllod

St Asaph Substation

Llys Dymper

Nant Bach

Gorsedd Bran

Derwedd Bach

Foel Goch

Tir Mostyn

Wern Ddu

Braich Ddu

St Asaph Substation!(!(

County Boundary

Existing Wind Farm!(Possible Wind Farm requiring SP Connection!(

Key:Study Area

TAN8 Strategic Renewables Energy Areas

Proposed Wind Farm Substation

400kV Overhead Lines132kV Overhead Lines33kV Overhead Lines

Distribution Network


Overview of the Project1.1 In July 2005, the Welsh Assembly Government

(WAG) published Technical Advice Note No 8 Planning for Renewable Energy (TAN 8). This document identified seven broad Strategic Search Areas (SSAs) for onshore wind farms in Wales. Four of these are in the SP Manweb network operating area. Of these, TAN 8 SSA A is in North Wales as shown in Figure 1.1.

1.2 Following publication of TAN 8, four wind farm developers have applied and agreed terms for SP Manweb to provide them with connections to the electricity grid network. As discussed in SP Manwebs Strategic Systems Options Report, after consideration of a number of options, these terms are based on SP Manweb providing a collector substation, to connect the power from the wind farms to a shared 132kV single circuit overhead line connection to the national transmission network at St Asaph.

1.3 The four contracted wind farm connections and their approximate Megawatt (MW) outputs are detailed below and shown in Figure 1.1. All wind farms are located within TAN 8 SSA A.

Clocaenog Forest (SJ013578)RWE NPower renewables have submitted a Development Consent Order application to the Planning Inspectorate to develop a new wind farm in Clocaenog Forest in North Wales. The forest is managed by Forestry Commission Wales on behalf of the Welsh Assembly Government. Clocaenog Forest wind farm is expected to generate between 64 and 96 MW, from 32 turbines. The turbines will have a total height (to tip) of 145m. The application was submitted at the end of March 2013.

Brenig (SJ021742)In February 2007, Brenig Wind Ltd received consent to build a 16 turbine wind farm at Llyn Brenig, with an installed generating capacity of 40MW. The turbines will have a total height (to tip) of 100m.

Nant Bach (SJ989470)In July 2011, Vattenfall received consent to build an 11 turbine wind farm at Nant Bach, with an installed generating capacity of up to 27.5 MW. The turbines will have a total height to tip of 100m. The 33kV connection to the SP Manweb collector hub will run underground through the Clocaenog Forest.

Derwedd Bach (SJ030500)Tegni received consent to build a 10 turbine wind farm at Derwedd Bach, with an installed generating capacity of 23 MW. The turbines will have a total height to tip of 120.5m. The windfarm connection to the SP Manweb collector hub will run underground through the Clocaenog Forest.

1.4 The proposed 132kV overhead line will connect into the recently extended SP Manweb substation at St Asaph (SJ021742). Because the connection can be accommodated within the SP Manweb ownership boundary, it is permitted under Part 17 Class G of the Town and Country Planning (GPD) 0rder 1995 and therefore no formal consent is required for the substation works at St Asaph.

1.5 As the project is required to connect new generation to the distribution network, the study is based on the current (April 2013) understanding of the status of the developers connection agreements. Under the terms of its distribution licence, SP Manweb is under contract to design and build the overhead line by the end of 2016.

Section 1.0: Introduction

North Wales Wind Farms Connection2

Figure 1.2- Connection Types: Double Wood Poles, Steel Tower, Undergrounding

Double Wood Poles p Double wood poles average 15m in height

and are spaced on average 100m apart.

p The poles carry three cables with an additional earth wire. The conductors are supported on a steel structure which sits on top of the double wood poles.

p This method of connection offers the greatest potential for sensitive routeing, in hilly, small scale landscapes.

Steel Towers L4p L4 towers average 26m in height and are

spaced on average 180m apart. The tower is slender in profile with a narrow base (4m x 4m). The towers can either be single circuit, carrying a 132kV line on one side, or double circuit, carrying two 132kV lines, one on either side.

p Steel towers offer less scope for sensitive routeing and are more suited to expansive, relatively flat landscapes. Their longer spans make them useful for crossing steep sided valleys which would be too steep for wood poles.

15m

Undergroundingp The trench for an underground cable is

approximately 1.5m wide. In agricultural land the overall working width would be approximately 15-20m. Cables can be laid in ducts in roads or across agricultural fields.

p Undergrounding may be appropriate where there are serious concerns about the potential adverse landscape and visual effects of an overhead line.

1.5m

Minimum2.0m


1.6 This Route Corridor Report, which has been prepared by Gillespies LLP on behalf of SP Manweb, forms part of SP Manwebs project development. Its aim is to:

p Outline the type of development for which routeing is required.

p Set out the routeing methodology used to develop the routeing options.

p Identify and assess the technical, economic, planning and environmental constraints to be taken into account in developing routeing options.

p Identify, describe and appraise routeing options, culminating in the selection of a Preferred Option.

About SP Manweb1.7 SP Manweb is part of the ScottishPower group

of companies responsible for the distribution of electricity in North Wales and is the network license holder for North and Mid Wales and Merseyside, Cheshire and parts of Shropshire. SP Manweb also maintains and manages the network in the same areas.

1.8 Within North Wales, SP Manweb works with customers who may require a connection for additional electricity supply or are looking to provide generation, which needs to be exported onto the network. Section 16 of the Electricity Act 1989 requires SP Manweb to provide such connections as and when it is asked to do so by any of its customers and this can lead to new network being built in areas where it doesnt exist already.

1.9 SP Manweb has established an approach to developing connection projects, which takes account of statutory procedures as well as the companys own objectives for achieving wide-ranging consultation throughout the project planning stages. The process starts by considering strategic scheme alternatives for connecting a customer onto the electricity network and then, once a preferred alternative is identified, work begins on identifying and appraising a number of route options. This then progresses to the selection and identification of a Preferred Route prior to formal Environmental Impact Assessment (EIA) and production of an Environmental Statement (ES).

Other Planned & Existing Wind Farms1.10 Additional wind farm developers have also been in

discussion with SP Manweb for connections onto the grid in and around SSA A. These developers are at different stages of the planning process and do not have signed connection agreements with SP Manweb. As such, they are not currently included in this project. The location and status of these projects (as of Spring 2013), together with existing wind farms in the area, is detailed below and shown in Figure 1.1.

p Gorsedd Bran scheme refused on appeal. Llys Dymper submitted to Conwy Council.

p Mynyd Mynyllod request for scoping submitted to IPC.

p Moel Maelogen existing wind farm with 33kV overhead line to Llanwrst.

p Tir Mostyn and Foel Goch existing wind farm with 33kV cable to Denbigh (25 turbines 21.25MW)

1.11 The routeing methodology has necessarily remained flexible to take account of these other wind farms and respond to any changes in the status of their connections. It will not now include any new wind farm connections as the circuit capacity is full with the four wind farms that have signed connection agreements. Any new wind farm will require a separate connection onto the Grid.

Project Description1.12 The proposed corridors from the collector

substation in the vicinity of the wind farms to the national transmission network at St Asaph, would allow for the connection to be made by overhead lines, underground cables or a combination of the two. Overhead lines could be built on steel towers (pylons) or double wood poles however the farmland through which the majority of the line would be built is considered to be more suitable for wood poles than steel towers. Steel towers may be considered in selected locations for example, crossing steep sided valleys such as the Elwy. Wood poles are preferred where technically feasible as they are less visually intrusive, less likely to be visible on the skyline and are more flexible for detailed routeing, providing a better fit with the landscape. Undergrounding may be appropriate where there are technical difficulties or serious concerns about the potential adverse landscape and visual effects of an overhead line.


1.13 The wood pole overhead line design proposed for the 132kV circuit is of double wood pole (OHL-132-03) design. These double wood poles have a maximum angle of line deviation of 35 degrees and are particularly suited to wind farm connections, which tend to be on higher ground and are subject to more adverse weather conditions. They are generally 15m in height (i.e. a 12.5m pole with 2.5m in the ground) and have an average span length of around 80m. However, both the height and span can be extended or reduced, as required to meet statutory clearance requirements or to address factors such as sloping ground. The poles carry 3-phase conductors (cables) in a single circuit network with an underslung earth wire, which incorporates a fibre optic cable for protection signaling and communication purposes. The four conductors are supported on a steel structure which sits on top of the double wood pole and are made of aluminium with the phase conductors having an overall diameter of 24mm and the earth/fibre optic wire being 14mm in diameter.

1.14 Where necessary to overcome technical issues, steel towers may be used. These are lattice towers of the L4 series, which are used widely across the UK. They are generally 26m in height and support three conductors (wires) suspended from the side arms of each tower with a four earth/fibre optic wire usually carried across the top of the towers. The towers have a standard height of 26m with a span of approximately 200m, but these dimensions can be extended or reduced as required, to meet statutory clearance requirements or to address factors such as sloping ground.

1.15 Underground cables may also be required to overcome technical issues or in areas of highest visual sensitivity. The trench for the underground cable is approximately 1.5m wide, with a working width for installation of 15-20m if a haul road is required. Cables can be laid in ducts in roads or across agricultural fields.

1.16 The three proposed connection methods are illustrated in Figure 1.2.

Role of this Document1.17 This Route Corridor Report is part of a suite of

documents, which will be developed over the course of the project and together demonstrate SP Manwebs commitment to developing a technically feasible and economically viable overhead line route, which causes the least disturbance to the environment and the people who live work and re-create within it. The suite of documents is outlined below, however these documents are not all currently complete and will be made available over time.

p Strategic Options Report - This document provides evidence of the need for the wind farm connections and sets out the strategic system options considered by SP Manweb for connecting the wind farms to the distribution network. A summary of the options considered and conclusions reached is set out below.

p North Wales Wind Farm Connection Strategic Environmental Alternatives - The purpose of this report is to inform the connection strategy by comparing a number of connection options from a landscape and visual perspective.

p Relative Landscape Sensitivity in Relation to 132kV Overhead Lines - This sets out an appraisal of the study area in terms of its theoretical landscape sensitivity to accommodating overhead lines of the type proposed.

p Route Corridor Report (this report) - This document forms the basis for the pre-application consultations and is supported by the Baseline Appendix, covering Landscape, Ecology and Cultural Heritage.

p Substation Siting Report This document carries out an appraisal of the potential siting locations for the collector substation at Brenig.

p Statement of Community Consultation (SOCC) - This document sets out the SP Manwebs agreed strategy for consultation - providing details of when, where, how and with whom does the consultation take place, including details of how feedback will be provided.

p Feedback Report This report sets out the consultation undertaken and the feedback received to date. It will be followed by further feedback reports as the consultation process moves forward in line with the SOCC.

p Consultation Report - This Reports document the outcome of the consultation(s) and SP Manwebs response to them.

p Environmental Statement - The project falls within the scope of the Electricity Works (Environmental Impact Assessment) (England and Wales) Regulations 2000 (Amended 2008) and the Infrastructure Planning (Environmental Assessment Regulations) 2009. These require formal Environmental Impact Assessment (EIA), with production of an Environmental Statement (ES) and accompanying Screening and Scoping Reports.


Strategic Options1.18 SPMs Strategic Options Report (May 2013)

presents the system option studies undertaken to identify the new network and infrastructure required to facilitate the customer connections. As the capacity of the existing network in the area is already fully utilised by the existing connected wind generation, the North Wales Wind Farms connection will require new infrastructure in the form of an additional 132kV circuit and new 33/132kV substation.

1.19 A number of options were considered to connect the four wind farms onto the existing grid network. Existing grid substations sites with the potential to connect to were considered in Wrexham and Flintshire as well as the chosen site at St Asaph.

1.20 The evaluation set out in the Strategic Options Report has confirmed that a new 33/132kV substation and a new 132kV circuit from SSA A to St Asaph are the appropriate distribution network reinforcements. This option is considered to be the most efficient, co-ordinated and economical way to connect wind generation in North Wales. The route corridor studies have been undertaken on this basis.

Undergrounding 1.21 SP Manweb has a licence obligation to develop

an efficient, coordinated and economical system. An overhead line solution typically facilitates compliance with these obligations. Overhead line solutions are more economical than cable alternatives to develop, as well as providing shorter return to service times under fault conditions.

1.22 SP Manweb accepts however that the justification for undergrounding should be considered on a case by case basis. These considerations would take into account cost and system design requirements, and the specific factors involved in each particular proposal, such as areas of high technical environmental constraint and areas of the highest recognised amenity value.

1.23 For 132kV projects cost estimates for underground cables are approximately four times more expensive than overhead lines. This can vary depending on ground conditions with it being more expensive to install cables within roads. It must also be recognised that the use of cable sections within a connection introduces additional technical issues within the network.

1.24 In terms of high amenity value, the approach in this project has been to develop a routeing methodology with the objective of avoiding areas of highest environmental value where possible.

This has resulted in route corridor options, as presented in the consultation, considered to be environmentally viable for the purposes of routeing overhead lines.

1.25 On the basis of the above, SP Manweb concludes that the economical cost of a wholly undergrounded option is not outweighed by the cost of the environmental impacts. However SP Manweb has not ruled out using some cable sections. The extent of cabling required will be guided by the outcome of more detailed environmental assessments in respect of the line design.

Statutory Consenting Requirements 1.26 The Planning Act 2008 (as amended by the

Localism Act 2011) (the Act) amended the existing planning system in England and Wales for consenting overhead lines.

1.27 The Act established the Planning Inspectorate within the National Infrastructure Directorate (NID) as the body responsible for examining and deciding development consents for large-scale infrastructure proposals, which qualify as Nationally Significant Infrastructure Projects (NSIPs). In accordance with Section 14(1)(b) of the Act, overhead lines installed above ground with a nominal voltage of greater than, or equal to, 132kV were considered NSIPs, to be determined by the Planning Inspectorate in accordance with the requirements of the Act. The overhead line component of this project falls within the parameters of a NSIP.

1.28 Applications will be determined in the context of the National Policy Statements, designated in July 2011. Those relevant to the North Wales Wind Farms Connections project are the Overarching National Energy Infrastructure Policy (EN-1) and draft Electricity Networks (EN-5).

1.29 The Substation component of this project is not classed as a NSIP and the planning application will therefore be determined by the Local Authority, in this case Denbighshire County Council. The potential location of the substation is discussed in more detail in the separate Substation Siting Report.

Structure of the ReportThe structure of the report is as follows:

Section 1.0 Introduction

Section 2.0 Approach & Routeing Principals

Section 3.0 Overview of Routeing Methodology

Section 4.0 Application of Routeing Methodology

Section 5.0 Findings of Corridor Appraisal

Section 6.0 Conclusion


SP Manwebs Statutory Duties2.1 As holder of the distribution licence for North

Wales, SP Manweb has a statutory duty, under Section 9 of the Electricity Act 1989, to:

develop and maintain an efficient, co-ordinated and economical system of electricity transmission.

2.2 Under Section 38 and schedule 9 of the 1989 Act, when planning new works, SP Manweb is also required to:

To have regard to the desirability of preserving natural beauty, of conserving flora, fauna and geological or physiographical features of special interest and of protecting sites, building and objects of architectural, historic or archaeological interest.

Do what it reasonably can to mitigate any effect which the proposals would have on the natural beauty of the countryside or on any such flora, fauna, features, sites, buildings or objects.

Approach2.3 The approach adopted for this project builds on

SP Manwebs experience in routeing overhead electricity transmission and distribution lines and uses established routeing methodologies. Recent SP Manweb projects in Wales include individual 132kV overhead line wood pole connections at Rhyl Flats (built), Llandinam (proposed) and Legacy/Oswestry (planned) and an ongoing major connection project for a number of wind farms in Mid Wales, comprising both tower and wood pole designs.

2.4 SP Manwebs approach is based on the principal that the major effects of an overhead line result from the individual or cumulative visibility of the towers or wood pole support structures along the route. The effects experienced by viewers vary depending on parameters such as viewing distance, cumulative effects, design, skyline position or backdrop. Since there is no technical way of reducing visual effects other than choice of towers or poles and only limited ways of achieving screening through planting, the most effective way of reducing visual intrusion is by careful routeing.

2.5 The approach developed for routeing the overhead line therefore takes account of the following:

p The Holford Rules, together with the National Grid Company and Scottish Hydroelectricity Ltd (SHETL) clarification notes.

Section 2.0: Approach & Routeing Principalsp R. Marshalls and R. Baxters 2002,

Strategic Routeing and Environmental Impact Assessment for Overhead Electrical Transmission Lines.

p Discussions held by SP Manweb with Conwy Council, Denbighshire Council and Wrexham Council.

p Discussions held by SP Manweb with NRW, Cadw and Denbighshire Council.

p Discussions held by SP Manweb with Forestry Commission Wales.

p SP Manwebs recent experience of routeing overhead lines in Wales including the Mid Wales Connections Routeing Study (2009-ongoing), Llandinam (2008-2010) and Tirgwynt (2008-2009).

2.6 The methodology comprises a number of broadly sequential steps (see flow chart below). As the Preferred Route must be technically and economically viable, the following checks are undertaken at each step:

p A review by SP Manwebs engineering design teamp A review by SP Manweb in relation to other

connections being developed within the study area.

2.7 It is important to note, however, that the methodology is iterative in nature, with the output of one stage informing the routeing and appraisal work of subsequent stages. Steps may be re-visited several times before a balance is achieved between technical, economic, planning and environmental considerations, with professional judgement being used to balance the factors. Flexibility is also required to allow any other connections that have been agreed, any changes to existing SP Manweb connections and any other connections that have come forward within the planning process.

2.8 Considerations, which have informed the development of the routeing methodology, are outlined below.

Technical Considerations2.9 Technical considerations relate to both construction

and operation of the overhead line. They include the location of operational and proposed turbines, existing overhead lines, altitude, rock outcrops, flood risk areas, steep slopes and peat deposits. Whilst not all of these technical considerations are absolute constraints, there is a presumption to avoid them wherever possible. The approach taken is to identify preferred environmental options informed by a staged review of technical issues.


2.10 Further details in relation to these technical constraints are provided within Step C of Chapter 4.0.

Economic Considerations2.11 In compliance with Section 9 of the Electricity

Act 1989, the proposed connections must be economical. This is interpreted by SP Manweb as meaning that as far as is reasonably possible, and all other things being equal, the connections should be as direct as they can be, and the routes should avoid areas where technical difficulty or compensatory requirements would render the schemes uneconomic.

Planning Considerations 2.12 A number of current planning policies set the

context within which electricity infrastructure proposals must be considered. These include UK wide and Welsh policy considerations such as the National Policy Statements (NPSs), the WAG Technical Advice Notes (TANs) and other planning policies and technical advice.

2.13 At a local level, the area is covered by two planning authorities. Denbighshire County Council covers the southern, eastern and northern parts of the study area and Conwy County Borough Council covers part of the western half. Both councils are currently in the process of producing Local Development Plans (LDP), to replace their current adopted development plans. Denbighshire have submitted their LDP to the Planning Inspectorate and are carrying out updates and Conwy are looking to adopt their LDP by August 2013.

2.14 For Denbigh, the Unitary Development Plan is the current adopted plan. For Conwy the current adopted plans comprise the Clwyd Structure Plan Second Alteration (Conwy Version), the Gwynedd Structure Plan, the Colwyn Borough Local Plan and the Llandudno/Conwy District Plan. Until 2004, the Council was preparing the Conwy Unitary Development Plan, which would have replaced the four adopted plans. Following advice from the Welsh Assembly Government, work on this plan has now ceased. Whilst it carries less weight than an adopted plan, it is still used in some circumstances in deciding planning applications.

2.15 The local plans refer to a number of planning policies and land allocations, which may have implications for routeing overhead lines in the area. These include:

p Flood Risk Areasp Housing Allocationsp Employment Allocationsp Mineral Sitesp Green Barriers/Protected Open Spacesp Open Space/Recreational Allocations

Environmental Considerations2.16 Statutory duties imposed by Schedule 9 of the

Electricity Act 1989 require licence holders to seek to preserve features of natural and cultural heritage interest and mitigate where possible any effects which their development may have on such features. The construction and operation of the overhead line will potentially have effects on the environment and the people who live, work and recreate within it, including effects on:

p Geology and Hydrology p Soils, forestry and agriculturep Visual amenity and viewsp Landscape characterp Tourism and recreationp Ecology including woodlandsp Cultural heritage including archaeologyp Traffic and transportp Residential amenity p EMFs and noise

2.17 Some of these environmental considerations are given more consideration at the later, more detailed, routeing and EIA stages.

Consultation Feedback Considerations2.18 The SOCC will set out the SP Manwebs agreed

strategy for formal consultation, including details of how feedback will be provided throughout the development of the project. Statutory agencies with an environmental remit including NRW, CADW, the Environment Agency Wales and Denbighshire and Conwy County Councils were advised of the emerging corridor designs and invited to respond to assist SP Manweb with its choice of preferred corridor.

2.19 The SOCC will also set out how future Public consultation events will be managed and feedback from the five public exhibitions in June 2012, three meetings with Community Councils and a further public exhibition in January 2013 have been recorded and analysed in the Feedback Report This feedback has been used to appraise the proposed corridors and assist SP Manweb with its choice of preferred corridor.


3.1 This chapter sets out the methodology for the identification of potential route corridors, the appraisal of those corridors and the identification of a preferred route corridor. It adopts the methodology developed by LUC and Gillespies for the current Mid Wales Connections Project for SP Manweb, adjusted as required to be appropriate to the North Wales Wind Farms Connection project.

Approach3.2 The primary objective of route selection is to

identify a technically feasible and economically viable overhead line route between specified points, which causes the least disturbance to the environment, and to the people who live, work, visit and enjoy the area.

3.3 The methodology for this study has been developed to meet the specific needs of this study although it builds upon SP Manwebs experience in planning and constructing new overhead line connections in Wales, England and Scotland and is based on both established methodologies and best practice. The approach is iterative and the steps taken may be revisited several times, applying professional judgement in order to achieve the best balance between environmental, technical and economic considerations. Consultation is an inherent part of the process as set out in the Statement for Community Consultation and supporting feedback reports.

3.4 SP Manwebs approach to routeing is based on the principle that the major effect of an overhead line relates to the visibility of the wooden poles or steel towers and the associated insulators and conductors. The effect experienced by a viewer will vary along the route corridor, dependant on factors including viewing distance, cumulative impact, design, skyline position and backdrop. Visual impact can be reduced through the choice of tower or pole(s) and through limited opportunities for screen planting; however the most effective way of reducing the degree of visual intrusion is by careful routeing.

Key Steps & Objectives3.5 The steps used in developing a methodology to

identify potential routes for the overhead line were developed based on the hierarchical Holford Rules, which were adapted to reflect the characteristics of the study area. The key steps of the routeing methodology for this project are summarised below. Steps were undertaken sequentially, with each step informing the next, culminating in the identification of a Preferred Route for the connection.

Section 3.0: Overview of Routeing Methodology

3.6 Further details of each step are provided in Chapter 4.0: Implementation of The Routeing Methodology.

3.7 In developing the methodology, the main objectives were to:

p Develop a methodology, which takes account of commercial considerations and the regulatory framework.

p Ensure that the project is responsive to changing design scenarios, which may emerge from SP Manweb connection agreements within TAN 8 SSA A.

p Progressively refine the potential options for the route of the overhead line, culminating in a Preferred Route.

3.1Phase Two

3.1Phase one

Technical Review

Consultation

step a: Identification of Broad Study Area

step B: Identification of Areas of Highest Environmental Value

step C: Identification of Technical Considerations

step D: Identification of Route Corridor Search Area

step e: Identification of Route Corridors

step F: Comparative Appraisal of Route Corridors

step G: Identification of Route Options

step h: Appraisal of Route Options to Identify Preferred Route

Routeing Methodology Key Stages


Established Practice for Overhead Line RouteingThe Holford Rules

3.8 It is generally accepted across the electricity industry that the guidelines developed by the late Lord Holford in 1959 for routeing overhead transmission lines, The Holford Rules, should continue to be employed as the basis for routeing high voltage overhead lines. The Holford Rules were reviewed circa 1992 by the National Grid Company (NGC) plc (now National Grid Transmission (NGT)) as owner and operator of the electricity transmission network in England and Wales, with notes of clarification added to update the Rules.

3.9 A subsequent review of the Holford Rules (and NGC clarification notes) was undertaken by Scottish Hydro Electric Transmission Limited (SHETL) and SP Transmission Ltd (SPT) in 2003. This review concluded that the Holford Rules should be used as originally formulated but with the NGCs notes of clarification modified and expanded to meet Scottish circumstances. Given the similarities between the Scottish and Welsh landscapes, the SHETL and SPT approach is considered relevant as the basis for this routeing study. References to the Holford Rules throughout this document therefore mean the Holford Rules (with NGC and SHETL notes). To relate to the Welsh situation, the SHETL and SPT notes have been amended where reference is made to designations. The Holford Rules and NGC and SHETL clarification notes are included in Appendix 1.

3.10 Whilst the Holford Rules relate specifically to steel tower lines, many of the principles can also be used as a guide to routeing wood pole connections.

LANDMAP3.11 LANDMAP1 is an information system devised

by the Natural Resources Wales (NRW), which comprises the nationwide collation and evaluation of information about the landscape, for use as a reference tool in developing landscape policy and assessing development schemes in the context of landscape impact. LANDMAP is advocated by Planning Policy Wales (PPW, 2002) which sets out the land use policies for the Welsh Government. PPW establishes the Governments objectives for conservation and improvement of natural heritage, in particular the protection of native habitats, trees and woodlands and landscapes with statutory designations.

1 LANDMAP data and background information is obtained from www.ccw.gov.uk/landmap.

3.12 LANDMAP provides detailed spatial information about five related datasets or aspects:

p Geological Landscape: the study of the geology, geomorphology and hydrology of the area.

p Landscape Habitats: the distribution of vegetation and habitats and the basis for landscape ecology.

p Visual & Sensory: identifies those landscape qualities that are perceived through the senses. It deals with the individual physical attributes of landform and land cover, as well as their visual patterns of distribution and sensory characteristics, and the relationships between them in a particular area.

p Historic Landscape: focuses on how archaeological and historical sites relate to each other and to the surrounding landscape.

p Cultural Landscape: considers the relationship that exists between people and places; how people have given meaning to places, how the landscape has shaped their actions and their actions have shaped the landscape.

3.13 Information is provided at several levels, allowing examination of broader areas (Level 2) and then a more detailed examination at Level 3. LANDMAP datasets recently achieved complete coverage of Wales and are now able to be considered in emerging projects.

3.14 A series of LANDMAP Guidance Notes provide advice on how LANDMAP can be used within a particular context. Whilst there is no specific guidance on the use of LANDMAP in routeing overhead lines, SP Manweb views LANDMAP as an invaluable tool in informing each step of the routeing process, in part as a resource for baseline environmental information but particularly as an appraisal/evaluation tool in the more defined routeing stages. On this basis, LANDMAP is used to inform the determination of landscape sensitivity as part of the initial stages of the routeing study (namely Steps A-E) with the use of LANDMAP also being proposed for the appraisal of the route corridors (Step F). Further to this, LANDMAP will also be used during detailed routeing (Steps G and H) and again as part of the EIA phase in terms of the assessment of likely significant environmental effects arising from the North Wales Wind Farms Connection project in accordance with the Infrastructure Planning (Environmental Impact Assessment) Regulations 2009.


Figure 4.1 - Project Study Area

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Foel Greon (390m)

Foel Gasyth (378m)

Moel Fodiar (390m)

Moel Tywysog (400m)

Mynydd y Gaer (270m)

BrenigClocaenog

Denbigh

St AsaphSt Asaph Substation

St Asaph Substation

Project Wind Farm Substation

Key:Study Area

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County Boundary

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Forestry Comission OwnedOpen Access Land

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TAN 8 SSA - Area A

AONB

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Foel Greon (390m)

Foel Gasyth (378m)

Moel Fodiar (390m)

Moel Tywysog (400m)

Mynydd y Gaer (270m)

BrenigClocaenog

Denbigh


St Asaph Substation


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County Boundary

Clocaenog Forest

Clwydian RangeAONB

LlynBrenig

Wind Farm Turbines:!( Foel Goch

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Forestry Comission OwnedOpen Access Land

Pentre-Llanrhaeadr

Vale of Clwyd

Hill Peaks!

TAN 8 SSA - Area A

AONB


Step A: Identification of Broad Study Area4.1 The first step of the routeing process is to identify a

broad study area, predominantly for the purposes of gathering data. In identifying the broad study area, it is important that this reflects known technical, economic, planning and environmental parameters at the outset, whilst retaining the flexibility to ensure that routeing is not constrained in any way by these parameters, through application of the iterative process outlined above.

4.2 The broad study area includes the maximum area across which a potential connection route was likely to be routed. It therefore included the proposed Clocaenog Forest and Brenig wind farms, which comprised the project as at December 2010, the northern part of TAN 8 SSA A and the existing St Asaph substation. Two additional wind farms at Nant Bach and Derwedd Bach are now included within the project, but as these lie to the south of the proposed study area and will be connected by underground cable the study area has not been extended to include them.

4.3 The study area is based upon making an informed decision about practical connection routes throughout the area, influenced by the distribution of higher ground and lower valleys.

4.4 Based on the parameters outlined above, the broad study area for the project is shown in Figure 4.1. The broad study area is the output of Step A. It was subject to review by SP Manweb, before being progressed to inform Step B.

Step B: Identification of Areas of Highest Environmental Value

4.5 Areas of Highest Environmental Value were mapped to further focus the study area, to highlight potential search areas for broad route corridors and identify potentially constrained areas.

4.6 This approach reflects the guidelines presented in The Holford Rules (as referred to in NPS EN-5), which have been adapted to reflect the characteristics of the study area for this project as described below. However where the Holford Rules use the term amenity this routeing study uses the term environmental to reflect more recent thinking which aims to recognise the intrinsic value of such areas.

Section 4.0: Application of Routeing Methodology

4.7 The Holford Rules are broadly hierarchical, with Rule 1 deemed the first rule to be considered in routeing. Rule 1 relates to the avoidance, where possible, of major areas of highest amenity value. Holford Rule 2 makes the following recommendation: avoid smaller areas of high amenity value or scientific interest by means of deviation. As the Holford Rules do not define what constitutes a major area (Rule 1) and the importance of an area is often irrespective of size, smaller areas (Rule 2) of high amenity value are also mapped at this stage alongside the larger areas.

4.8 The Holford Rules do not identify which designated areas constitute areas of highest amenity value. However, SHETL clarification note b) states that areas of highest amenity value require to be established on a project-by-project basis considering Schedule 9 of the Electricity Act, 1989 and provides examples to be considered.

4.9 The National Policy Statement EN-1 sets out a need to avoid the most important environmental sites, including those designated at international, European and national level. However the need to give due consideration to sites of regional and local importance is also outlined in EN-1, although these designations should not be used in themselves to refuse consent.

4.10 Areas of highest environmental value located within the broad study area, and therefore considered within the routeing process, comprise the international, European and national level designations listed below and shown on Figure 4.2:

p Areas of Outstanding Natural Beauty (AONBs)p Special Areas of Conservation (SACs)p Sites of Special Scientific Interest (SSSIs) p National Nature Reserves (NNRs)p Regionally Important Geodiversity Sites (RIGS)p Scheduled Monuments (SAMs)p Historic Landscapes p Registered Parks and Gardens p Conservation Areas p Listed Buildings


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Conservation Area

Scheduled Monuments

AONB

Parks & Garden -Essential Setting

SAC

NNR

Historic Landscapes

RIGs Areas

SSSIRegistered Parks & Gardens

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Conservation Area

Scheduled Monuments

AONB

Parks & Garden -Essential Setting

SAC

NNR

Historic Landscapes

RIGs Areas

SSSIRegistered Parks & Gardens

Figure 4.2 - Highest Environmental Value


4.11 The following international and national level designations are not present within the broad study area:

p National Parks p Ramsar Sitesp Special Protection Areas (SPAs)p World Heritage Sitesp Registered Battlefields (not presently defined in

Wales)

4.12 Whilst Historic Parks and Gardens are non-statutory designations, they are referred to in the notes accompanying Holford Rule 1, and these designated areas are included as Areas of Highest Environmental Value.

4.13 Similarly Conservation Areas (a local level designation) and clusters of Listed Buildings, are included as Areas of Highest Environmental Value, as these correspond generally with population centres and are listed as examples of areas of highest amenity value. Individual buildings will be considered during the later routeing stages when deviation around them is required.

4.14 The Supplementary Notes to the Holford Rules state avoid routeing close to residential areas as far as possible on grounds of general amenity. At this stage in the routeing study, principal settlements, towns and villages as identified in the relevant local plans (Denbighshire and Conwy) are mapped and included as constraints at this level as areas of primarily residential amenity.

4.15 Based on the geographic locations of the Areas of Highest Environmental Value in relation to the proposed wind farms and St Asaph substation, it is considered likely that broad corridors can be identified, which avoid passing through these areas1.

4.16 As a material consideration in the determination of applications and given their non-statutory designated status, registered Historic Landscapes are also considered as Areas of Highest Environmental Value to be avoided where possible. Where such areas cannot be avoided, due to their size and location in relation to the wind farms, an appraisal, known as an ASIDHOL, of each registered Historic Landscape may need to be undertaken at the detailed routeing stage to seek to ensure that effects on these areas are minimised during routeing.

4.17 As discussed above, small areas of highest environmental value, as defined by Rule 2 of the

1 It is recognised that the legislative requirements for SACs (and SPAs) extend to the protection of the integrity of the site including qualifying habitats or species and these areas will be reflected at the detailed routeing stage.

Holford Rules, have been mapped and included in this step of the routeing study. SHETL note a) on Holford Rule 2 also states that other areas of regional or local high amenity value should be identified from development plans. For this routeing study, these include the following areas identified as being of high local value:

p Wildlife Trust Site (WTS)p Local Wildlife Site (LWF)p Ancient Woodlands

4.18 For clarity, the following local level designations are not present within the study area:

p Local Nature Reserves (LNRs)

Step C: Identification of Technical & Planning ConstraintsTechnical Constraints

4.19 Areas of high ground and steep slopes form a technical and environmental constraint to routeing. Guidance provided by Rules 4 and 5 of the Holford Rules, states overhead line infrastructure is more widely visible when located on higher ground, particularly ridges and skylines.

4.20 To identify topography, a Digital Elevation Model (DEM) employed for mapping topography is used which maps gridded Ordnance Survey (OS) Panorama data with a resolution of 50m. To identify slope angles the slope is calculated from the Panorama DEM using ArcGIS Spatial Analyst.

4.21 Based on the above, topography and slope angle are categorised in relation to the technical constraint posed to routeing of wood poles and steel towers as advised by SP Manweb in the table below:

Topographic Feature

Wood Pole Constraint

Steel Tower Constraint

Slope Angle o22 degrees Avoid where possible

Minimise lengths

Height (AOD)450m Avoid where

possibleMinimise lengths

Technical constraints are shown in Figure 4.3.


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> 451m AOD301 - 400m AOD

Height

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Slope Over 22Slope Between 15-22

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> 451m AOD301 - 400m AOD

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Slope Over 22Slope Between 15-22

Figure 4.3 - Technical Constraints


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Landscape Sensitivity (LANDMAP)

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Medium (30-32)

Medium-Low (26-29)

Low (22-25)


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Figure 4.4 - Landscape Sensitivity (LANDMAP)


Figure 4.5 - Broad Route Corridors

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Link: Links and Creates Blue / Red Corridorand Blue / Green Corridor

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LANDMAP4.28 LANDMAP is used as an information tool to inform

an appraisal of the theoretical sensitivity of the landscape within the broad study area to overhead lines. The method used is described in North Wales Wind Farms Connection; Relative Landscape Sensitivity in Relation to 132kV Overhead Lines (Gillespies on behalf of SP Manweb 2011). The approach builds on work produced by landscape architects at Gillespies and LUC for the on-going Mid Wales Connections Project and earlier projects at Llandinam and Tir Gwynt. The outcome of the appraisal is a map categorising the broad study area into one of five sensitivity categories, ranging from low through medium-low, medium, medium-high to high, as shown in Figure 4.4. This map is used to help identify the Route Corridor Search Area, and in more detail at the corridor appraisal stage as outlined below.

Iterative Analysis4.29 The desk based work, including multiple layers

of mapped information (including topography, elevation, drainage pattern, environmental designations, and landcover, including forestry) were considered alongside field work to obtain a thorough understanding of the character of the landscape and its sensitivities.

4.30 The Areas of Highest Environmental Value and technically constrained areas were comparatively unrestrictive in identifying areas where potential Overhead Line Corridors should be avoided. Therefore it was also necessary to supplement the information obtained from the desk top appraisal with a more extensive field based critique of the study area landscape to develop and narrow down potential corridors.

4.31 This iterative routeing process culminated in the identification of three broad route corridors linking the proposed wind farms to the St Asaph substation as shown in Figure 4.5, all of which are considered to be both technically and environmentally viable at this preliminary stage. A link between corridors also introduces a further two combination routes, giving a choice of five potential corridors.

Step D: Identification of Route Corridor Search Area

4.22 Those areas which are not considered to be of Highest Environmental Value or technically constrained are considered to be viable for routeing at this stage.

4.23 Where Areas of Highest Environmental Value or technically constrained areas cannot be avoided entirely, the aim is to minimise the potential impacts on these areas. For example, where there was a requirement to pass over a topographical feature, the smallest practical extent was crossed via a low point or watershed. Linear environmental features (eg SSSIs which follow watercourses) were crossed at a perpendicular angle where feasible.

Step E: Identification of Route Corridors4.24 Taking into account the constraints identified above

and informed by the intrinsic characteristics of the landscape, a number of route corridors were identified between the Brenig and Clocaenog Forest wind farm substations and the St Asaph substation.

4.25 This process comprised desk based work, initially taking account of guidance provided by the Holford rules and additionally considering:

p The Tan 8 Strategic Search Areasp The sensitivity of the landscape to overhead line

development informed by analysis of LANDMAP.

4.26 The use of LANDMAP and the TAN 8 Strategic Search Areas to inform routeing at this stage are discussed further below.

TAN 8 SSAs4.27 The TAN 8 SSAs were mapped as shown in Figure

4.1 to understand where a considerable degree of landscape change is, or will be happening driven by policy and national need for wind energy generation. As such the sensitivity of the landscapes in these areas to further changes through the development of connection infrastructure may be lower. The addition of new overhead line infrastructure may also constrain future wind farm development. However given the location of the Brenig and Clocaenog Forest wind farm substations on the northern edge of TAN8 SSA A this criteria does not usefully inform the routeing process for this project.


Broad Route Corridor descriptionsRed Corridor

4.32 Initially this corridor runs north-east from the Brenig wind farm substation across the high ground north of Clocaenog Forest to a tee point at Hafotty-las where it joins with the corridor running north west from the Clocaenog Forest wind farm. From here it runs broadly parallel to the B4501 before swinging to a more northerly direction west of Saron, crossing the B5435 east of Nantglyn and continuing on through the farmland of the Rhos Hills. At Segrwyd Goch the corridor then turns to run in a north westerly direction, crossing the A543 north east of Groes. At Waen Fawr the corridor turns to continue in a more northerly direction across rolling and open farmland below Moel Fodiar to the west and Hafod Wood and Cefn Berain to the east. Llannefydd lies to the west of the corridor and as the corridor passes to the east of this settlement and Mynydd y Gaer it swings back to a north-easterly direction. The corridor then crosses the wooded valley of the River Elwy where it joins the route of a 33kV overhead line, which it then parallels as far as the existing 400kV overhead line near St Asaph Business Park. From here the line will be undergrounded into the existing SP Manweb St Asaph substation.

Green Corridor 4.33 This corridor departs from Red Corridor (described

above) to the east of Groes, running more directly north, passing to the east of Eriviat Hall and Park and to the west of Henllan. From here the corridor runs slightly to the north-west, re-joining Red Corridor west of Bont-newydd.

Blue Corridor4.34 This corridor departs from Red Corridor (described

above) near Saron where, instead of swinging to the north-west, it continues to follow the B4501 through rolling farmland to the east of Foel Gasyth. At Peniel the corridor crosses the B4501, west of Segrwyd Ucha, and crosses the wooded valley of the River Ystrad near Kings Mill Wood. From here it runs northwards, skirting the western edge of Denbigh and the eastern edge of Denbigh Golf Club, before joining the route of a 33kV overhead line north of the town. It then runs broadly parallel to this line passing Plas Heaton to the west and Nant-y-Patrick to the east and crossing the Elwy valley at Chapel Wood. From the existing 400kV overhead line on the south-west side of St Asaph the line will be undergrounded into the existing SP Manweb St Asaph substation.

Blue/ Red Link Corridor4.35 This corridor departs from Blue Corridor (described

above) near Peniel and cuts north west to join the Red Corridor at Bach, just above Serwyd Goch, following the Red Corridor to St Asaph Business Park.

Blue/ Green Link Corridor4.36 This corridor similarly departs from Blue Corridor

near Peniel and cuts north west to join the Green Corridor at Bach, running north and following the Green Corridor to St Asaph Business Park.

Step F: Comparative Appraisal of Route Corridors

4.37 The comparative environmental appraisal of the route corridors from the wind farms onto the existing network was undertaken in stages as set out below.

p Identification of appraisal criteria, objectives and appraisal indicators as set out in Table 4.1:

p Application of appraisal criteria to all corridors following the method for appraising in Table 4.1 to present the factual environmental appraisal baseline;

p Comparative appraisal of corridor options for each connection, (Red, Green, Blue, Blue/Red and Blue/Green), to identify the corridor with the least environmental impacts;

4.38 A subsequent appraisal of the potential location for the collector substation will be carried out following selection of the preferred corridor, and including any potential cumulative effects.

4.39 The above methodology follows that developed by Gillespies and LUC on behalf of SP Manweb for the current Mid Wales Connections Project.

4.40 An appropriate level of information and appraisal for this strategic routeing stage of the project has been included, where further information is required to refine the project during the detailed line routeing and/or EIA stages this has been highlighted within the report.

4.41 The overall methodology is based on the three aspects influencing route selection; environment, technology and consultation. A review of the environmental criteria for each corridor and an appraisal of those criteria is carried out to determine the corridor which has the least environmental effects. The corridors are also reviewed by SP Manweb to assess any technical criteria which could affect the choice of corridor. Feedback back from the consultation process is appraised and the corridors are given an order of preference


for this aspect. The corridor selection is then determined by weighing the three aspects against each other to select the preferred corridor which has the preferred balance between environmental, technical and consultation response.

4.42 Table 4.1 gives the environmental criteria applied, the reason for the inclusion of those criteria (objectives) and an outline methodology for appraising each corridor against the criteria.

4.43 The criteria are identified to:

p Continue to reflect both the overall routeing objective which is to identify technical and economical routes for electrical connections that meet the technical requirements of the electricity network and cause, on balance, the least disturbance to the environment and the people who live work and recreate within it

p Continue to reflect the Holford Rules p Consider policy on the assessment of impacts

set out in Part 5 of the overarching National Policy Statement for Energy EN-1 and Part 2 of National Policy Statement for Electricity Networks Infrastructure EN-5. NPS EN-5 is specific to electricity networks and specifically

lists biodiversity and geological conservation (including ornithology), landscape and visual assessment and technology specific information. NPS EN-1, in setting out policy for a range of energy infrastructure, includes a range of criteria to be included in assessments and in addition to the ones already mentioned in EN-5, includes topics such as historic environments and flood risk.

p Draw out distinctions between the corridors to enable the relative strengths and weaknesses of each to be identified.

4.44 The environmental appraisal is based on seeking to minimise impacts using a qualitative approach supported by quantitative information where appropriate. Qualitative appraisals with support from SPM have been made through applying professional judgement by ecologists, landscape experts and archaeologists to comment on biodiversity, landscape and visual impacts and historic environments respectively. Where expert professional judgement can be supported by data/information in a quantitative format this has been included, for example the number of designated sites potentially affected.

Table 4.1: Criteria for Environmental Appraisal of Route CorridorsCRITeRIon sUB-CRITeRIa MeThoD FoR aPPRaIsInGLength of Corridor

None Calculate length using Geographical Information Systems (GIS).

Biodiversity and Geological Conservation

(Holford Rules 1 & 2 & Supplementary Note b.)

NPS EN-1 and NPS EN-5

p Special Area Conservation (SAC) p Site of Special Scientific Interest

(SSSI)p National Nature Reserve (NNR) p Wildlife Trust Sites (WTS) (WTNR)p Local Wildlife Site (LWS)p European Protected Species and

Ornithologyp Peatland Habitats

GIS based quantitative assessment and qualitative appraisal i.e. descriptive text in relation to potential for a route to be identified to avoid direct and indirect impacts on these designated areas.

Strategic scale appraisal of European Protected Species and ornithological activity within the study area and professional judgement applied in relation to potential routeing issues.

Potential effects on peat are considered to relate to loss of peatland habitats e.g. blanket bog.


CRITeRIon sUB-CRITeRIa MeThoD FoR aPPRaIsInG

Landscape and Visual amenity

(Holford Rules 1, 2, 3, 4 & 5 & Supplementary Note b.)

EN1 and EN5

p AONB GIS based quantitative assessment and qualitative appraisal including descriptive text in relation to potential for a route to have indirect impacts on these designated areas i.e. if corridor located


4.46 Further information in relation to each criterion is provided below.

i. Length of Corridor4.47 Holford Rule 3 states that other things being equal,

choose the most direct line, with no sharp changes of direction and thus few angle towers. This indicates that a shorter length of corridor is likely to lead to lower potential environmental impacts than a longer route, once other constraints and issues have been examined. The length of each Route Corridor is calculated as part of the appraisal.

ii. Biodiversity and Geological Conservation 4.48 Figure 4.6 indicates designated sites and locations

of other areas of biodiversity and geological conservation interest included within the appraisal in accordance with Rule 1 and Rule 2 of the Holford Rules. As the figure shows, the identification of route corridors seeks to avoid areas of nature conservation value where possible. However, due to their size, nature and location, some of these are difficult to avoid in this process. Where relevant, these are identified in the appraisal and the potential implication for future routeing and assessment, i.e. scope to avoid these at the detailed routeing stage, noted.

4.49 The appraisal has been carried out using GIS based identification of the location and nature of the important area, in relation to the route corridor and then considering the potential for a route to be identified that avoids these areas within the corridor. This enables an appraisal of how constraining such areas might be whilst having regard to the reason why particular sites are designated or highlighted as being of conservation importance.

4.50 The Supplementary Note b) of the Holford Rules relating to Designations of Regional and Local Importance states where possible choose routes which cause the least disturbance to Areas of Great Landscape Value and other similar designations of Regional or Local Importance. For this study,

these areas of relevance for nature conservation are Wildlife Trust Sites(WTS) and Local Wildlife Sites (LWS). At this strategic level, this appraisal has been carried out with reference to the Baseline Report, which will be updated to feed into the Environmental Statement, prepared for SP Manweb by Gillespies in association with Peak Ecology.

4.51 Whilst towers and poles can be readily constructed on peat, potential environmental effects associated with construction on peat are considered to relate to loss of peatland habitats and loss of carbon storage with implications for climate change. NRW has produced a LANDMAP based Phase 1 Habitat for the whole of Wales. From this, peatland related habitats are mapped and used as a proxy for peatlands and a semi-quantitative appraisal undertaken.

iii. Landscape and Visual Amenity4.52 In accordance with Rule 1 of the Holford Rules

and the Routeing Objective, routeing should seek to avoid compromising the purposes of designations of nationally designated landscapes such as Areas of Outstanding Natural Beauty and National Parks. Whilst the routeing stages have ensured no proposed corridors are located within a nationally designated landscape, there are some areas of the Clwydian Range AONB where the overhead line may be visible and the distance of a corridor to these areas is highlighted. The AONB is mapped on Figure 4.1. As outlined above, the Supplementary Note b) of the Holford Rules relating to Designations of Regional and Local Importance states where possible choose routes which cause the least disturbance to Areas of Great Landscape Value and other similar designations of Regional or Local Importance. Special Landscape Areas (SLAs2), and other locally designated landscapes are being replaced in the Local Development Frameworks (LDFs), and it is understood that local landscape designations will be superseded

2 A non-statutory designation applied by the local plan-ning authority to define areas of high landscape impor-tance.

CRITeRIon sUB-CRITeRIa MeThoD FoR aPPRaIsInG

Flood Risk

EN1

Flood Zones B and C Flood Zones B and C are considered.

Forestry and woodland

(Holford Rules 4 & 5)

p Ancient and Semi-Natural Woodland

p Other Forestry and Woodland

GIS based qualitative appraisal woodland areas in relation to Ancient and Semi-Natural Woodland data and March 2011 National Forest Inventory (NFI) data.


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Route Corridors

Link: Links and CreatesBlue / Red Corridorand Blue / Green Corridor

Red Corridor

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SACWindfarm Habitat ManagementPlan Areas: T.B.C - awaitinglayer

Local Wildlife Site (LWS)

Wildlife Trust Sites#*

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Peatland Habitat (LANDMAP phase 1 survey)

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SACWindfarm Habitat ManagementPlan Areas: T.B.C - awaitinglayer

Local Wildlife Site (LWS)

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SSSI

Peatland Habitat (LANDMAP phase 1 survey)

Figure 4.6 - Biodiversity and Geology


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Historic LandscapeLandscape Habitats

Cultural Landscape

Visual & Sensory

Regional TrailNational Footpath

Regional Cycle Route

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National Cycle Route

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Figure 4.7 - Landscape and Visual Resources


Figure 4.8- Field based Landscape Sensitivity

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by the application of Quality Assured LANDMAP data following LANDMAP Guidance Note 1. As the Denbighshire UDP (1996-2011) is due to be replaced by the Local Development Plan and does not identify any Special Landscape Areas no local landscape designations are mapped and taken account of during this stage of routeing. The Conwy Local Development Plan- Revised Deposit 2011 Strategic Policy NTE/1 seeks to respect, retain and enhance the local character and distinctiveness of the Landscape Character Areas. It recognises that LANDMAP will be used to review and amend Landscape Character Areas as that information becomes available and no locally designated landscape areas identified within the LDP.

4.53 Whilst areas evaluated as LANDMAP Outstanding and High areas were taken account of during identification of the route corridors (steps A E above), these do not form constraints to avoid where possible as:

i) some of the wind farms requiring connection are located within these areas, and

ii) LANDMAP does not currently identify areas with the same status as designated sites.

4.54 To aid the appraisal of corridors LANDMAP areas evaluated as Outstanding for all five aspects as shown on Figure 4.7 have been taken account of. This is appraised using GIS based quantitative assessment, i.e. length of corridor within the area and qualitative appraisal, i.e. descriptive text in relation to potential for a route to be identified to avoid areas of higher sensitivity to overhead lines.

4.55 A desk based theoretical landscape sensitivity study was undertaken to inform Phase 1 of the routeing process, based on LANDMAP data. This was an initiative proposed in consultation with NRW as a tool for applying LANDMAP and for which no other sensitivity mapping existed previously. The development and outcome of this study is detailed in the North Wales Wind Farms Connection: Relative Landscape Sensitivity in Relation to 132kV Overhead Lines (March 2011). Following on from this, a detailed field based study was undertaken to inform Phase 2 routeing. This sought to identify at a more local scale, the relative sensitivity of areas within which the corridors are located, to overhead line routeing. Sensitivity is assessed as low, medium-low, medium, medium-high or high.

4.56 The methodology used for judging sensitivity in the field is based on consideration of a number of criteria. These have been applied to the selected route corridors in order to enable comparisons to be made. The findings of the field-based landscape sensitivity assessment differ from those of the LANDMAP derived sensitivity in a number

of ways. Overall, the field-based assessment is considered to better reflect the relative landscape sensitivity of the corridors within the study area, as informed by desk based study and targeted field based evaluation undertaken by experienced landscape architects who are familiar with the proposed development. This is thought to be a more appropriate and focused basis for appraisal, compared with one based purely on theoretical sensitivity.

4.57 The field based landscape sensitivity of the identified corridors to overhead lines is mapped on Figure 4.8.

4.58 Further Notes on Clarifications to The Holford Rules c) states minimise the visual effect perceived by users of roads and public rights of way, paying particular attention to the effects of recreational, tourist and other well-used routes. On this basis, views from National Trails, roads, and visitor attractions have been taken into consideration when appraising route corridors, whereby potential visibility of the overhead line from these areas has been highlighted through professional judgement and presented in a qualitative format. This includes trails such as the Clwydian Way, key tourist roads such as the B4501 and locally known scenic viewpoints, such as Llyn Brenig and Moel Fodiar, which may also comprise nature conservation sites and gardens open to the public where their setting may potentially be affected. National/Regional walking and cycling trails are mapped on Figure 4.7 along with key roads and viewpoints marked on the OS map.

iv. Historic Environment4.59 The identification of route corridors sought to avoid

areas of cultural heritage value where possible, for example Listed Buildings, Scheduled Ancient Monuments and Conservation Areas. However, owing to their numbers, size and location, some of these were difficult to avoid in their entirety, and potential implications for future routeing and assessment will be considered in more detail at the detailed routeing stage.

4.60 This appraisal involved GIS based identification of the location and type of each designated cultural heritage asset including its setting and principal views where relevant, supported by descriptive text in relation to the potential for a route to be identified within the corridor to avoid these. Cultural heritage features included within the appraisal of the Historic Environment are shown on Figure 4.9. At this strategic level, this appraisal has been carried out with reference to the Baseline Report, which will be updated to feed into the Environmental Statement, prepared for SP Manweb by Gillespies in association with CPAT.


Figure 4.9 - Historic Environment

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Figure 11 - Flood Risk

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4.61 Cadw, NRW and the International Council on Monuments and Sites UK have collaborated to produce a Register of Landscapes of Historic Interest in Wales, the use of which is outlined in the Guide to Good Practice on Using the Register of Landscapes of Historic Interest in Wales in the Planning and Development Process, Cadw (2007). The Register, which contains 58 historic landscapes in total, was issued in two parts, with 36 outstanding and 22 special historic landscapes; although the Guide states that both are considered to be of equal value and all registered historic landscapes should be considered in the same way.

4.62 The Guide states that all Landscapes of Historic Interest identified on the Register are of national importance in the Welsh context, and although the Register does not currently impose statutory controls, Cadw has advised that these may be given statutory status in the near future. There are three Historic Landscapes in the study area; the Denbigh Moors, the Vale of Clwyd and the Lower Elwy Valley and the constituent character of the first two of these designations are reflected in their Historic Landscape Character Areas (HLCAs). A HLCA has not been prepared for the Lower Elwy Valley.

4.63 Given the broad nature of the route corridors and the status of the detailed technical design, in seeking to assess the likely effects on registered Historic Landscapes at this stage, SP Manwebs advisers have developed a preliminary approach, and a strategic level assessment has been undertaken. This appraisal is undertaken through GIS based quantitative assessment i.e. the area likely to be visually affected as a proportion of the Historic Landscape.

v. Residential Amenity4.64 In addition to avoiding settlements in accordance

with the Holford Rules (Rule 7 and residential areas supplementary note a)), proximity to both settlements and individual properties is taken account of within the appraisal of route corridors, with the aim of avoiding proximity to residential properties as far as possible on the grounds of general amenity. The location of residential properties has been mapped as shown on Figure 4.10 and the potential for avoiding effects on residential amenity during detailed routeing has been identified through professional judgement. This work has been supported by an appraisal of potential impacts on visual amenity which is included in Appendix 2: North Wales Wind Farms Connection: Route Corridor Visibility Appraisal.

4.65 The Route Corridor Visibility Appraisal mapped the location of residential properties within the corridor

and a 1km buffer, locating the principle view from each property and the nature of that view. The resulting plans were used to identify areas of potential impact to inform the corridor appraisal process.

vi. Flood Risk4.66 In relation to potential conflicts with policy relating

to flooding, flood zones B and C for Wales have been mapped using GIS and the potential for avoiding locating steel towers and wood poles within the floodplain identified as shown on Figure 4.11.

vii. Forestry and Woodland4.67 Two of the Notes in respect of Rules 4 and 5 of the

Holford Rules state where possible follow open space and run alongside, not through woodland or commercial forestry and consider opportunities for skirting edges of copses and woods. Protect existing vegetation, including woodland and hedgerows.. In addition to protected woodland such as ancient and semi-natural woodland, woodland and commercial forestry identified within the National Forest Inventory (NFI) is also being avoided where possible during routeing. Forestry and woodlands have been mapped as shown on Figure 4.12 and the potential for avoiding these areas during detailed routeing identified.

Additional Considerations - Technical Review: 4.68 As shown in the routeing flow chart in Section One,

SP Manwebs methodology includes technical feedback. Therefore, the comparative appraisal has included a review of possible technical issues within each corridor.

4.69 SP Manwebs technical team has considered criteria which it considers influences the general buildability of connections as follows:

p length;p altitude (i.e. ground conditions and exposure to

climate/weather);p topography;p windfarm development areas;p access (for construction and maintenance);p proximity to existing electrical infrastructure;p major road/railways crossings;p flood risk areas and/or river crossings;p proximity to dwellings.

4.70 For each to the identified corridors these criterion have been considered assuming the majority of the line would comprise double wood poles, with possible sections of undergrounding and/or steel towers being used as appropriate as the line design develops.


Figure 12 - Forestry and Woodland

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4.71 The findings of the technical review for each corridor are presented within the appraisal tables. The outcome of the appraisal indicates that all the corridors are technically viable, although all three cross the Elwy valley where steel towers may be required locally to span the steep slopes and valley sides. In addition, the Blue route may be constricted above Denbigh Quarry and further south where the corridor crosses the steep sided valley of the Afon Ystrad.

Additional Considerations - Consultation Feedback:

4.72 The consultation process has also been carried out as an inherent part of the iterative routeing process including consultation with both statutory stakeholders and the local communities. The comments received from both have been used to inform the selection of the preferred route corridor.

4.73 Statutory agencies with an environmental remit were advised of the emerging Project design and the proposed routeing methodology in the early planning stages during 2010 and 2011. SP Manweb presented the Project to Natural Resources Wales, Conwy and Denbigh County Council, Cadw, Clwyd Powys Archaeological Trust and the Welsh Assembly Government (Department of Economy) who, collectively, SP Manweb refers to as stakeholders for the purpose of this Report.

4.74 The stakeholders were invited to a workshop event in February 2011 and feedback was received from these bodies both within the work shop, in further written responses and in discussion at the public exhibitions (see below). The stakeholders response where given has been fed into the tables below.

4.75 Community consultation was held through a number of public exhibitions held in June 2012 with an additional event in January 2013. The exhibitions were visited by approximately 400 people and 254 responses were received. Four additional meetings were held with Llansannan, Bodelwyddan, Llannefydd and Henllan Community Councils. The findings of the consultation are detailed in the Public consultation feedback on broad route corridor options report. The main principles and findings of the consultation are detailed below.

4.76 The feedback was analysed in a number of ways:

p Route Corridor Preferences: The feedback form asked respondents to rank their preference for the three broad route corridors from 1 to 3. The report includes those preferences broken down by corridor and preference.

p Written Feedback Analysis: Written feedback was received in a variety of ways including the

feedback forms, individually drafted letters and form letters signed by members of the public. In order to produce useful data to feed into the selection of a route corridor all the written feedback has been analysed statistically by how they related to 15 key issues and which corridors they are in relation to.

p Detailed Comments: While empirical analysis of written feedback is very useful for p

M4687 20130503 Route Corridor Report

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