Gills Bay 132 kV Consultation Document
July 2013
Scottish Hydro Electric Transmission plc
Gills Bay – 132 kV
Consultation Document
Published by Scottish Hydro Electric Transmission plc 10 Henderson Road Inverness IV1 1SN
July 2013
Scottish Hydro-Electric Transmission plc Gills Bay 132 kV Consultation Document
CONTENTS
GLOSSARY I
EXECUTIVE SUMMARY I 1 INTRODUCTION 1 1.2 The Next Stages 1 1.3 Statutory Consents Procedure 2
2 THE NEED FOR THE PROPOSALS 3 3 ROUTING STUDY 4 3.1 Background to the Routing Study 4 3.2 Objectives of the Routing Study 4 3.3 Methodology 4 3.4 Identification of Environmental Sensitivities and Constraints 5 3.5 Connection Options Development 6 3.6 Environmental Analysis of Route Options 7 3.7 Comparison of Preferred Connection Options 7 3.8 Draft Limits of Deviation 7
4 ENVIRONMENTAL FEATURES AND SENSITIVITY OF THE STUDY AREA 8 4.1 Introduction 8 4.2 Key Environmental Features 8 4.3 Environmental Sensitivity within the Study Area 12
5 SUMMARY OF ROUTING STUDY FINDINGS 16 5.1 Introduction 16 5.2 Environmental Analysis of Connection Options 16 5.3 Comparison of Lattice Steel tower and Twin Trident (woodpole) supports 17
6 THE PROPOSALS 20 6.1 Draft Limits of Deviation 20 6.2 Line Design and Construction 20
7 CONSULTATION ON THE PROPOSALS 24 7.1 The Proposals 24 7.2 Questions for Consideration by Consultees 24
ANNEX A: FIGURES
ANNEX B: ENVIRONMENTAL BASELINE DATA SOURCES
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Caithness Reinforcements - Consultation Document Gills Bay 132 kV
Comments on this document should be sent to: Gavin Steel Scottish Hydro Electric Transmission plc 10 Henderson Road Inverness IV1 1SN e-mail address for representations: [email protected]
Copies of this document can be found online at: www.sse.com/GillsBay
Copies will be placed on deposit for public viewing during normal opening hours at the following locations:
Thurso Service Point Caithness Planning and Building Council Offices Standards Office Rotterdam Street Market Square Thurso Wick KW14 8AB KW1 4AB
Caithness Horizons Mey Village Hall High Street Thurso Caithness KW14 8AJ
Public consultation exhibitions will be held in late August 2013 and the details of these will be advertised shortly. Please submit comments by: 9 September 2013
Published by: Scottish Hydro Electric Transmission plc (SHE Transmission)
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GLOSSARY 132 kV 132 kilovolt capacity of an electricity power line AOD Above Ordnance Datum BGS British Geological Society Conductor (wires) support type The type of structure used to support overhead conductors, typically either lattice steel towers or trident wood poles, that is to be used for connection of the electricity transmission network Connection option A combination of route alignment and conductor support type Consent application An application for development consent under section 37 of the Electricity Act 1989 EIA Environmental Impact Assessment ES Environmental Statement GWDTE Groundwater Dependent Terrestrial Ecosystem Holford Rules A set of principles, first developed in 1959 by Sir William Holford, which guide the route selection process and which continue to inform transmission line routing in the UK LCT Landscape Character Type Listed Building A building that has been recognised through the Planning (Listed Buildings and Conservation Areas) (Scotland) Act 1997 as of special architectural or historical interest. LOD Limit of Deviation, an area which defines the practical limits within which micro-siting of the OHL infrastructure can occur within the terms of the s37 consents which are to be sought. The purpose of Limits of Deviation is to allow flexibility within a s37 consent for the final micro-siting of individual towers to respond to localised ground conditions, topography, engineering and environmental constraints Micrositing The process by which the final position of a structure is defined within the LOD, taking account of a range of localised engineering, technical and environmental factors. NCN National Cycle Network OHL Overhead line Planning application An application for planning permission under the Town and Country Planning (Scotland) Act 1997, as amended by the Planning etc. (Scotland) Act 2006 Preferred route The route option which is considered to represent the optimum balance between the various environmental, technical and economic factors considered herein
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Preferred connection option The preferred route and conductor support type combination (the Proposals) The Proposals The preferred connection option and key design parameters on which consultation is now sought. Proposed Development The final connection option which will be brought forward with an application for consent Proposed route The final route alignment which will be brought forward with an application for consent Route alignment The route followed by a transmission line across the land Route option One of several possible alignments which a new transmission line could follow Routing Study The process of selecting a preferred connection option for a new transmission line Scoping Report A report submitted under regulation 7 of the EIA Regulations providing information of the information to be included within the Environmental Statement (ES) Section 37 application (s37) An application for development consent under section 37 of the Electricity Act 1989 SAC Special Area of Conservation SAM Scheduled Ancient Monument; a monument of national importance that Scottish ministers have given legal protection under the Ancient Monuments and Archaeological Areas Act 1979 SHE Transmission Scottish Hydro Electric Transmission plc SLA Special Landscape Area SPA Special Protection Area SSSI Site of Special Scientific Interest Study area The area of land, at its widest extent, which was considered within the route selection process, defined here as the broad area between Thurso to the west, Gills Bay to the east, the coast to the north and Durran and Reaster to the south. SEPA Scottish Environment Protection Agency SNH Scottish Natural Heritage VP Vantage Point locations overlooking the study area from which ornithology surveys were carried out. ZTV Zone of Theoretical Visibility
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EXECUTIVE SUMMARY This consultation document invites all interested parties to comment on the proposals by Scottish Hydro Electric Transmission plc (SHE Transmission) to construct a new 22 km double circuit 132 kV overhead line (OHL), supported by lattice steel towers, between a proposed new substation south of Thurso (Thurso South substation) and a new substation at Gills Bay (Gills Bay substation). The proposals will provide connection to the transmission system for two new marine electricity generation projects currently under development to the north of Wick. This consultation document outlines the process by which the preferred connection option has been selected. Comments are now sought from a range of statutory authorities, key stakeholders, elected representatives and the general public. In early 2013 SHE Transmission completed a routing study to select a preferred connection option, comprising a preferred route alignment and a preferred conductor support type. The objectives of the routing study were:
to identify alternative route options between the proposed Thurso South substation and the proposed Gills Bay substation capable of supporting a 132 kV OHL;
to assess the environmental implications of connection options, i.e. each combination of route option and conductor support type (lattice steel tower or twin Trident woodpole); and
to select a preferred connection option likely to cause least disturbance to the environment and amenity. The proposed 132 kV OHL between Thurso and Gills Bay will be constructed using lattice steel towers. The towers will vary in height, to accommodate changes in topography and where the line crosses roads and rivers, although the standard height will generally be in the region of 26 m up to a maximum of 40 m. An initial study area was defined for the consideration of environmental constraints, which covered the broad area between Thurso to the west, Gills Bay to the east, the coast to the north and Durran and Reaster to the south. Identified environmental constraints in this area included (amongst Others): Special Areas of Conservation (SAC); Special Protection Areas (SPA); Special Landscape Areas (SLA) Sites of Special Scientific Interest (SSSIs); listed buildings; scheduled monuments; sensitive ecological habitat types; areas of concentrated bird activity; areas of grade 3 agricultural land; watercourses; various major and minor roads; proposed wind farms; areas of flood risk; and areas of recreational amenity. The preferred connection option which has been identified extends from the proposed new Thurso South substation near Geiselittle to a proposed new substation south of Gills Bay (Philips Mains), via the south side of the Hill of Olrig and Moss of Greenland, and comprises a lattice steel tower configuration. The design of the proposals will be informed by this consultation exercise and through continuing detailed surveys, which may identify any as yet unknown engineering, environmental or land use constraints which may require modifications to the route alignment before finalising the proposed route. A proposed route will then be brought forward with an application for consent.
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When providing your comments and feedback, SHE Transmission would be grateful for your consideration of the questions below:
Is the rationale for the project clearly set out in the consultation document?
Is the approach to the selection of the preferred route, identifying the optimum balance of technical, economic and environmental feasibility, clearly set out?
Are there any factors you consider may have been overlooked or given either insufficient or too much consideration during the selection process?
Do you have any other comments about the preferred route?
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1 INTRODUCTION
1.1.1 This consultation document invites interested parties to comment on the proposals by Scottish Hydro Electric Transmission plc (SHE Transmission) to construct a new 22 km double circuit 132 kV overhead line (OHL) supported by lattice steel towers between a proposed new substation south of Thurso (Thurso South substation)1 and a new substation proposed at Philips Mains, south of Gills Bay (new Gills Bay substation) (Figure 1).
1.1.2 This consultation document outlines the process by which both the preferred route and the preferred conductor support type (the ‘preferred connection option’) have been selected. Comments are now sought from statutory authorities, key stakeholders, elected representatives and the public on the routing process and the preferred route described. These comments will inform further consideration of the route and the eventual selection of a proposed route for which consent will be sought.
1.1.3 A separate 'Scoping Report' will be issued to consult specifically on the proposed scope of and approach to the Environmental Impact Assessment (EIA) which will be undertaken according to the provision of the Electricity Works (Environmental Impact Assessment) (Scotland) Regulations 2000 (as amended). Structure of the Document
1.1.4 This Consultation Document includes:
Section 1: Introduction: describes the purpose of the consultation document.
Section 2: The Need for the Proposal
Section 3: Routing Study: summarises the main stages and key considerations of the routing study.
Section 4: Environmental Character: describes the environmental characteristics of the study area within which the preferred connection option has been developed, based on desktop and detailed site surveys.
Section 5: Summary of the Routing Study Findings: provides a summary of the findings of the routing study, including rationale supporting the selection of the preferred connection option.
Section 6: The Proposals: provides an overview of the proposals including the anticipated general design and typical construction methods.
Section 7: Consultation on the Proposals: invites comments on the route and the routing study.
1.2 The Next Stages
1.2.1 Following the completion of the consultation process, SHE Transmission will review all comments received. Together with the assessment of environmental impacts undertaken as part of the EIA process, the comments will be used to develop and
1 SHE Transmission submitted a planning application for the Thurso South substation in February 2013.
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refine the preferred route and select a proposed route to bring forward for consent application.
1.2.2 SHE Transmission will apply for consent under Section 37 of the Electricity Act 1989 (The 1989 Act). The intention is to bring an application for consent to the Scottish Ministers in early 2014.
1.3 Statutory Consents Procedure
1.3.1 Applications for consent for the construction of OHLs are considered by the Scottish Ministers under the terms of the 1989 Act. As part of the application for consent, SHE Transmission will also request that planning permission for ancillary works associated with OHLs, such as the establishment of access requirements, be deemed to be granted under section 57(2) of the Town and Country Planning (Scotland) Act 1997 (the 1997 Act).
1.3.2 Following receipt of all views and representations, the Scottish Government will determine the application for consent in one of two ways:
Consent the proposal, with or without conditions attached; or
Reject the proposal.
1.3.3 The new substation development at Gills Bay has been part of an earlier consultation exercise undertaken by SHE Transmission and is not considered as part of this consultation document. The substation site will be the subject of a separate application for planning permission under the Town and Country Planning (Scotland) Act 1997 and further consultation will be undertaken in due course.
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2 THE NEED FOR THE PROPOSALS
2.1.1 SHE Transmission is the transmission license holder in the north of Scotland and has a duty under Section 9 of the Electricity Act 1989 to facilitate competition in the generation and supply of electricity. The company also has obligations to offer non- discriminatory terms for connection to the transmission system, both for new generation and for new sources of electricity demand.
2.1.2 In March 2010, the Crown Estate announced the successful companies that will develop marine generation in the Round 1 lease areas in the Pentland Firth and Orkney Waters. This includes a generation potential of up to 1600 MW (wave and tidal). Initial applications from marine developers suggest the earliest developments could be ready for connection by 2016 growing thereafter up to the full capacity potentially by 2020, assuming successful proving of the technology in the early years.
2.1.3 Two tidal developers have accepted SHE Transmission’s connection offers, phased between 2016 and 2018/2019.
2.1.4 System studies performed by SHE Transmission System Planning have established that this anticipated capacity exceeds that available within the existing network in the north of Scotland; further, there is currently no transmission infrastructure in the Gills Bay area where some of the marine generation is to be located.
2.1.5 Subsequent studies have established the need for a new 132/33 kV substation in the Gills Bay area, and a new overhead double circuit 132 kV connection between this and the proposed new substation to be developed at Thurso South.
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3 ROUTING STUDY
3.1 Background to the Routing Study
3.1.1 In order to address the need for the proposals as set out within section 2, a series of studies have been carried out. These have included:
High level corridor studies were completed to examine options for the reinforcement of transmission infrastructure in Caithness, including but not limited to the connection considered here. 2 Site selection studies were completed and identified a proposed substation location at Philips Mains, and initial consultations have been held with The Highland Council (THC), Scottish Natural Heritage (SNH) and Scottish Environment Protection Agency (SEPA). An initial public exhibition was also held in 2011.
A routing study was also completed which comprised evaluation of alternative route alignments and constructor support type capable of accommodating a new 132 kV double circuit connection, independent of tower design. The findings of this study are presented within this document.
3.2 Objectives of the Routing Study
3.2.1 The objectives of the routing study were:
to identify alternative route options between the proposed Thurso South substation and the proposed Gills Bay substation capable of supporting a 132 kV OHL, independent of conductor support type;
to assess the environmental implications of each connection option (i.e. route option and conductor support type combination); and
to select a preferred connection option likely to cause least disturbance to the environment and amenity.
3.3 Methodology
3.3.1 The approach adopted has been informed by SHE Transmission guidance3, which sets out the key routing principles for high voltage lattice steel tower transmission OHLs. The flowchart below summarises the routing study methodology.
3.3.2 The guidance refers to the application of the “Holford Rules” to inform routing. These rules advocate the application of a hierarchical approach to routing which first avoids major areas of highest amenity, then avoids smaller areas of high amenity, and finally considers factors such as backdrop, woodland and orientation.
2 The substation site will be the subject of a separate application for planning permission under the Town and Country Planning (Scotland) Act 1997 and further consultation will be undertaken in due course. 3 SHE Transmission (2004) Electricity Transmission Development Proposals in Scotland, The Scottish Hydro-Electric Transmission Limited (SHETL) Approach. A Guidance Document Outlining the SHETL Approach to the Routeing of High Voltage Steel Lattice Tower Transmission Lines, Leading to an Application for Consent in Scotland.
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Flowchart 1: Approach to Route Selection
3.4 Identification of Environmental Sensitivities and Constraints Study Area
3.4.1 The study area was defined as the broad area between Thurso to the west, Gills Bay to the east, the coast to the north and Durran and Reaster to the south. Baseline Conditions
3.4.2 Initial desk studies established the key environmental features of the study area, specifically:
areas, sites, features (designated or otherwise) protected at the international, national and local level;
known areas outwith designations, which support designated species (particularly ornithology);
settlements with visibility within and towards the study area (based on Zone of Theoretical Visibility (ZTV) plans);
agricultural land;
areas prone to flooding (1:200 year return);
water bodies;
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existing wayleaves;
existing and consented wind farms; and
existing infrastructure (roads, footpaths). Baseline Environmental Sensitivity
3.4.3 For ease of description and interpretation, the study area was divided into four sections as described below:
Thurso to Hill of Olrig;
Hill of Olrig to Wester Olrig Cottages;
Wester Olrig Cottages to Greenland; and
Greenland to Gills Bay.
3.4.4 With reference to the identified environmental characteristics of the study area, overall environmental sensitivity for the four parts of the study area was established. This is presented in Chapter 4 of this report.
3.5 Connection Options Development Conductor Support Types
3.5.1 Three conductor support types were considered initially:
lattice steel towers; 4 twin Trident (woodpole) configuration ; or 5 dual Trident (woodpole) configuration :
3.5.2 Initial engineering and business case studies concluded that the dual Trident configuration did not present a feasible alternative. This configuration was therefore not considered further. Route Options
3.5.3 Initial route options were generated based on a series of engineering led parameters in order to identify technically feasible connection options for consideration.
3.5.4 Figure 2 illustrates the different connection options considered.
3.5.5 Four options were selected capable of accommodating a connection using either lattice steel towers or twin Trident (woodpole) supports (Options 1, 1A, 2 and 3). One further option (Option 4) was identified capable of accommodating a twin Trident (woodpole) structure only.
4 Comprising two 132 kV OHL circuits supported on Trident woodpole supports, running in parallel along a single route alignment. 5 Comprising two 132 kV HL circuits support on Trident woodpole supports following different alignments between the two substations.
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3.5.6 Engineering site visits were conducted throughout the Spring and Summer of 2012 and in early 2013. All route options were inspected to ground truth desk-based information and to confirm the engineering feasibility of each.
3.6 Environmental Analysis of Route Options Route Options for Lattice Steel Towers
3.6.1 Each route option (Options 1, 1A, 2 and 3) was examined to establish the anticipated interaction of a lattice steel tower OHL with key environmental features and sensitivities.
3.6.2 Analysis was completed by section, as described above.
3.6.3 For each section, (as described in paragraph 3.3.3) a qualitative appraisal was made of the interaction of lattice steel towers along each route option with the identified environmental features and sensitivities focussing on factors which helped to differentiate the options. For some environmental features, no clear preference emerged. In some cases, preferences were marginal only. In general however, the appraisal allowed a preferred route through each section to be identified.
3.6.4 Following this, the relative sensitivity of the receiving environment through each section was considered in order to ensure that the overall preferred route favoured the least environmentally constrained option, particularly through areas of highest environmental sensitivity. Route Options for Twin Trident (woodpole) structures
3.6.5 The same process of environmental analysis as described above was also applied for twin Trident configuration (Options 1, 1A, 2, 3 and 4) resulting in the identification of a preferred route option for twin Trident OHL configuration.
3.7 Comparison of Preferred Connection Options
3.7.1 The preferred route option for lattice steel tower OHL was then compared against the preferred option for twin Trident (woodpole) OHL, to establish an overall preferred connection option (i.e. route option and conductor support type combination) (‘’the proposals’).
3.7.2 This was completed via a systematic process of considering environmental constraints, topic by topic, against key design parameters (e.g. height, width, span length) for each conductor support type.
3.8 Draft Limits of Deviation
3.8.1 Finally, through an iterative process of design and subsequent appraisal, indicative draft three dimensional Limits of Deviation (LOD) have been developed capable of accommodating the proposals in a manner which minimises the potential for adverse environmental impact whilst giving sufficient flexibility for establishing access, tower siting and final routing. This draft LOD remains indicative at this stage, and will be developed further during the detailed design process and during consultation and may be subject to amendment before the proposed LOD which will form part of the s37 application can be confirmed.
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4 ENVIRONMENTAL FEATURES AND SENSITIVITY OF THE STUDY AREA
4.1 Introduction
4.1.1 This chapter sets out the key features of the existing environment and the overall environmental sensitivity within the study area.
4.2 Key Environmental Features Ecology
4.2.1 There are a number of designated sites within the study area. These are listed in Table 4.1 below in order of size and shown in Figures 3a and 3b.
Table 4.1: Ecologically Designated Sites Designation Name Site Site Area Comments Centre (ha) Location SAC, SPA, Ramsar Caithness and 333403 1,410 South-east of study and SSSI Sutherland Peatlands 967943 area (Stroupster Peatlands) SAC, SPA, Ramsar Caithness and 331958 1,385 South-east of study and SSSI Sutherland Peatlands 964434 area (Stroupster Peatlands) SPA, Ramsar and Caithness Lochs (Loch 325434 101 In eastern part of SSSI Heilen) 968419 study area SAC River Thurso 314200 353 Western extent of 949000 study area SPA North Caithness Cliffs 319109 14,063 Northern part of study (Dunnet Head) 976324 area (at Dunnet Head) SPA, Ramsar and Loch of Mey 327052 68 Northern part of study SSSI (biological) 973610 area SSSI (biological and Dunnet Links 322243 792 Northern part of study geological) 969176 area SSSI (biological) Philips Mains Mire 330736 59 Eastern extent of 970730 study area SSSI (biological) Loch of Durran 320777 39 Central study area 965542 SSSI (biological) River Thurso 311112 49 Western extent of 966314 study area SSSI (biological) Dunnet Head 318696 61 Northern part of study 975749 area
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4.2.2 An Extended Phase 1 Habitat Survey was undertaken across the study area, (July 2011)6. Habitats within the study area predominantly comprise improved/semi- improved grassland with occasional areas of marshy grassland, wetland, coniferous plantation, waterbodies and very occasionally dry heath. For the purposes of this report, areas of marshy grassland have been considered to have potential to be Groundwater Dependent Terrestrial Ecosystems (GWDTE).
4.2.3 Bog habitats (considered to be of greater sensitivity than other habitats in the study area) are predominately located in the eastern and north-east of the study area. The majority of bog habitats were identified to be Wet Modified Bog with the remaining habitats Blanket Bog.
4.2.4 There are no major watercourses in the study area; a number of drains, ditches and burns do exist however. The River Thurso is to the immediate west of the study area. A Protected Species survey, carried out in September 2012, confirmed certain watercourses within the study area as suitable to support water voles and also have the potential to support otter populations. Ornithology
4.2.5 Ornithology surveys were carried out from selected vantage points (VPs). Between 50 and 54 survey hours were completed over a 12-month survey period at each VP location, and each VP watch was 2 hours long. One complete passage-winter- passage seasons (September 2011 – April / May 2012) and one complete summer breeding season (April / May 2012 - August 2012) were surveyed.
4.2.6 Ornithology data identifies flight lines and roaming survey data for selected species including Greylag, White-fronted and Pink-footed geese, Whooper swan and Hen harrier within the study area.
4.2.7 Hen harrier flight lines were predominately recorded in the southern part of the study area. However, some flights were recorded in the north-east and western parts.
4.2.8 Geese and Whooper swan flight lines were recorded within the majority of the study area to varying degrees. Flight activity was found to be more prevalent in the south and north-eastern areas. Landscape
4.2.9 The study area includes a variety of landscape character types. The majority of the area is occupied by Mixed Agriculture and Settlement with occasional smaller areas of Small Farms and Crofts. The north-eastern part of the study area lies within the Sweeping Moorland landscape character type (LCT). There are small patches of Coniferous Woodland Plantation in the central and north-eastern parts of the study area and an Inland Loch (Loch Heilen) in the eastern part of the study area. In the wider area to the north of the study area is the Dunnet Head Special Landscape Area (SLA) which covers 2,350 ha around a prominent headland with vertical cliffs and moorland. North of the study area, and within the SLA area, is an area of Long Beaches, Dunes and Links landscape character type.
6 ENVIRON UK Ltd (July 2011) Caithness Reinforcements: Preliminary Environmental Appraisal and Proposed Scope and Methods of Further Survey
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Visual Amenity
4.2.10 The topography of the study area generally consists of gradually undulating terrain with few significant hills or impediments to views. The exception to this is the Hill of Olrig (NGR 317957 965657) which reaches an elevation of 141 m AOD, and also an extensive area of forestry which exists in the north-eastern part of the study area.
4.2.11 The topography of the area allows for long range views which include the two main centres of population in the area, Thurso and Castletown. Archaeology and Cultural Heritage
4.2.12 Features of cultural heritage interest are shown on Figures 3a and 3b. The majority of Scheduled Ancient Monuments (SAMs) in the vicinity of the study area are recorded as small “mounds”, “cairns” and remains of “brochs”. A cluster of SAMs has been identified associated with Olrig House located to the south-west of Castletown, including the scheduled remains of St Trothan’s Church.
4.2.13 Listed Buildings in the vicinity of the study area are predominantly Category B and C; however there are two Category A buildings in the wider area; Dunnet Parish Church and Castle of Mey. A number of Category B and C listed buildings are in close proximity to the route options in the area around Olrig, south-west of Castletown.
4.2.14 Additional features of potential archaeological interest identified include Fryster and Easter Durran farmsteads at Durran; a hut circle and possible broch at Red Moss; and two farmsteads at Greenland. Recreation and Tourism
4.2.15 Key tourism and recreation features within the study area are shown on Figures 3a and 3b. National Cycle Network (NCN) route 1 is present within the study area, running from Thurso in the west, in a south-easterly direction on Mount Pleasant Road to Mayfield then north-east to Castletown from where the route continues in a general north-easterly direction past Greenland, Inkstack and on to Rigifa.
4.2.16 Within the study area, a Core Path (CA03.05) is located on the Hill of Olrig (NGR 317957 965657) and is 0.3 km in length.
4.2.17 South of the study area a second Core Path (CA02.01) follows part of the B876 road for 0.7 km at Bower (NGR 323624 962974)
4.2.18 To the west of the study area the River Thurso is considered to be important for salmon fishing.
4.2.19 A visitor centre, campsite and forest walk (within Dunnet Forest) are located north of the study area near to Dunnet (NGR 322125 970332). Agricultural Land and Landholdings
4.2.20 Agricultural land capacity and known land ownership have been considered. Within the study area agricultural land is predominately of Class 3.2 (suitable for a moderate range of crops) though some scattered areas of Class 6.2/6.3 (suitable only for rough grazing) are present along the route options. There is no Class 1, Class 2 or Class 3.1 land (capable of supporting arable agriculture) within the study
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area. There are scattered areas of Class 4 (suitable for a moderate range of crops) and Class 5 (capable of supporting improved grassland) to the north of the study area.
4.2.21 A large area of forestry occupies land in the north-east of the study area surrounding Philip Mains and the proposed sub-station at Gills Bay.
4.2.22 Significant wetland is present in the eastern part of the study area with some wetland extending northward along the edges of the forest area. Additional wetland areas are located in proximity to the Hill of Olrig. Geology, Hydrology and Hydrogeology
4.2.23 Potential geological and hydrological constraints are shown on Figures 3a and 3b. There are two sites designated for geological interest within the study area, as detailed in Table 4.2.
Table 4.2: Geologically Designated Sites Designation Name Site Centre Site Area Comments Location (ha) SSSI (biological and Dunnet Links 322243 792 Northern part of study geological) 969176 area SSSI (geological) Weydale Quarry 314507 3 Western part of study 965399 area
4.2.24 The geology in the vicinity of the study area typically comprises drift deposits of diamiction, boulder clay with isolated pockets of peat. The BGS mapping for the area shows peat outcropping more heavily towards Gills Bay to the east. Alluvium deposits are located around Durran and Borgie Mains. Further Alluvium is located around Loch Heilen. These drift deposits are further underlain by bedrock comprising Upper Caithness flagstone group, including Scrabster Flagstone, Achrscrabster Flagstone, and Sandside Bay sandstone. The Upper Caithness flagstone group is generally described as laminated carbonate rich siltstones and shales with subordinate fine-grained, thinly bedded sandstones. The BGS 1: 625 000 mapping for the area groups the solid geology over the study area into the Middle Old Red Sandstone
4.2.25 The BGS Hydrogeology and Groundwater Vulnerability Maps (1: 625 000) indicate that the site is underlain by a moderately permeable aquifer. While the Upper Caithness Flagstone Group will seldom produce large quantities of water for abstraction, it is important for local supplies and for supplying base flow to rivers. Within the Caithness area the bedrock is classified as a locally important aquifer, and groundwater is largely confined to a shallow zone of weathered rock and borehole yields are limited.
4.2.26 Potential GWDTE habitats (marshy grassland) are located throughout the study area (see paragraph 4.1.65).
4.2.27 Surface water features within the study include the named Murkle Burn and Gill of Broynach, near Mayfield, the Burn of Garth, near Wester Olrig and the Burn of Hollandmey, near Bowermadden. In addition, there are various drainage ditches and smaller streams throughout the study area. Loch Heilen is situated in the central
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study area, and Loch of Mey is located to its north, in the northern part of the study area.
4.2.28 Flood risk areas have been identified with reference to the Scottish Environment Protection Agency (SEPA) online flood risk mapping, which shows area at risk of flooding in the 1 in 200 year flood event. There are two identified areas of flood risk within the study area. These correspond to areas adjacent to the River Thurso and an area surrounding the drain which becomes the Burn of Durran, producing a flood plain of approximately 100 m in width between Wester Olrig and Borgie Mains. Other Infrastructure
4.2.29 The following proposed wind farm sites occur within the study area:
Earl’s Cairn wind farm: scoping stage; and
Lyth wind farm; scoping stage.
4.2.30 In addition, the proposed Meygen tidal project is located to the east of Gill’s Bay, which includes a proposed Power Conversion Centre and underground cable in the eastern-most extent of the study area.
4.2.31 These are shown on Figure 3b.
4.3 Environmental Sensitivity within the Study Area
4.3.1 As described above environmental sensitivities exist throughout the entire study area, although not uniformly. In order to identify areas of highest overall environmental sensitivity the environmental features specific to each section (as described in paragraph 3.3.3) have been considered below.
4.3.2 Environmental sensitivity has been considered qualitatively, based on professional judgement and with reference to the frequency and type of ‘Areas of Highest Amenity Value’, as set out within the Holford Rules as shown in Table 4.3 below:
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Table 4.3: Indicative parameters for considering overall environmental sensitivity Sensitivity Indicators High Multiple occurrences of ‘Areas of Highest Amenity Value’ as defined within the Holford Rules. International/European/Nationally designated sites, features or species. Key views and or open/sensitive landscape character. Multiple sensitivities across a range of environmental topics.
Medium Some occurrences of ‘Areas of Highest Amenity Value’ as defined within the Holford Rules. Some sensitivities, limited to a small range of environmental topics and mostly at regional or local level. Low Regional or Local level environmental sensitivities only. No occurrences of ‘Areas of Highest Amenity Value’ as defined within the Holdford Rules. Few environmental sensitivities identified.
Thurso South to Hill of Olrig
4.3.3 The main environmental designations in this part of the study area are limited to the Weydale Quarry geological SSSI, and the Tulloch of Shalmstry Scheduled Monument. Habitat representing potential for GWDTE, as protected under the Water Framework Directive, has also been identified in this area.
4.3.4 No ecologically designated sites (International/European/National level) have been identified in proximity to the route options in this part of the study area, although the River Thurso SAC and the North Caithness Cliffs SPA are located c. 50 m and 4 km, respectively, from the proposed Thurso South substation which marks the western extend of the options under consideration.
4.3.5 Ornithology data suggests that bird activity by designated bird species (Greylag Goose; White Fronted Goose; Whooper swan; and Hen harrier) associated with the identified SPAs (North Caithness Cliffs SPA and Caithness Lochs SPA) is limited throughout this part of the study area.
4.3.6 A number of regional and/or local environmental sensitivities exist including residential receptors scattered throughout this part of the study area.
4.3.7 The overall sensitivity of the environment in the area between Thurso South and Hill of Olrig, based on the parameters set out in Table 4.3 above, is therefore considered to be Medium. Hill of Olrig to Wester Olrig Cottages
4.3.8 A number of environmental designations exist within this part of the study area, including Loch of Durran SSSI and the western extent of the Dunnet Links SSSI. The Dunnet Head element of the North Caithness Cliffs SPA lies to the north of Castletown. Dunnet Head is also designated as a Special Landscape Area (SLA).
4.3.9 Ornithology data shows pronounced clusters of bird activity within this area, relating to both feeding/loafing and flights of SPA designated bird species, including Greylag geese and Whooper swan. Hen harrier activity is also noted within this part of the study area.
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4.3.10 Habitat representing potential for GWDTE, as protected under the Water Framework Directive, has also been identified in this area.
4.3.11 In addition, a number of Scheduled Monuments and Listed Buildings exist associated with Olrig House, which are sensitive to potential effects either through direct disturbance or as a result of effects on setting.
4.3.12 The Hill of Olrig is considered to be sensitive as it is an area of open, elevated topography providing limited opportunity for natural screening of new infrastructure.
4.3.13 In addition, a number of regional and/or local environmental sensitivities exist through this part of the study area, including the settlement at Castletown and other residential receptors scattered throughout the area.
4.3.14 The overall sensitivity of the environment in the area between Hill of Olrig and Wester Olrig Cottages, based on the parameters set out in Table 4.3 above, is considered to be High. Wester Olrig Cottages to Greenland
4.3.15 Dunnet Head SSSI is located within the north of this part of the study area, with the Dunnet Head SLA and North Caithness Cliffs (Dunnet Head) SPA designations beyond that, to the north. The Earney Hillock chambered cairn SAM is located near Bowermadden.
4.3.16 Ornithology data indicates some activity within this part of the study area; roaming data indicates some activity of Greylag goose and Whooper swan in the northern part, with Pink Footed geese (not an SPA designated species), noted in the southern part. Recorded flight activity is concentrated towards the Loch of Durran SSSI and around the Moss of Greenland. Small areas of habitat representing potential for GWDTE, as protected under the Water Framework Directive, have also been identified within this part of the study area particularly associated with the Moss of Greenland at the easternmost extent.
4.3.17 The overall sensitivity of the environment in the area between Wester Olrig Cottages and Greenland, based on the parameters set out in Table 4.3 is considered to be Medium. Note that the environmental sensitivity in the northern part of this area is considered greater than the southern part, due to the concentration of ‘Areas of High Amenity Value’ in the northern part. Greenland to proposed Gills Bay substation (Philips Mains)
4.3.18 A number of environmental designations exist within this part of the study area, including both the Loch of Heilen and the Loch of Mey, which form component parts of the Caithness Lochs SPA and Ramsar site. In addition, the majority of the area designated as Dunnet Links SSSI lies within this part of the study area. The Dunnet Head element of the North Caithness Cliffs SPA lies to the north of Castletown. Dunnet Head is also designated as a SLA.
4.3.19 Habitat representing potential for GWDTE, as protected under the Water Framework Directive, has also been identified in this area.
4.3.20 Ornithology data indicates pronounced activity with this part of the study area, relating to both feeding/loafing activity of SPA designated bird species, particularly around Loch Heilen and also at the proposed Gills Bay substation site. Flight
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activity for Greylag goose and Whooper swan is concentrated to the south of Lochend and then again around the proposed Gills Bay substation. A further focus of activity for Pink Footed goose (not an SPA designating species) has been recorded to the north of Lochend at Syster. Hen harrier activity has also been recorded on Hill of Slickly.
4.3.21 In addition, a number of Scheduled Monuments and Listed Buildings exist in this part of the study area, including the Castle of Mey (Grade 1 Listed Building) and the Earl’s Cairn scheduled monument which are sensitive to potential effects either through direct disturbance or as a result of effects on setting.
4.3.22 The landscape in this part of the study area is categorised as sweeping moorland character type, which is also considered sensitive to change as a result of its open and undeveloped characteristics. There are also areas of plantation forestry located towards the proposed Gills Bay substation.
4.3.23 The overall sensitivity of the environment in the area between Greenland and the proposed Gills Bay substation (Philips Mains), based on the parameters set out in Table 4.3, is considered to be High.
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5 SUMMARY OF ROUTING STUDY FINDINGS
5.1 Introduction
5.1.1 As described in Chapter 3, a range of connection options was identified based on engineering feasibility. These are shown on Figure 2.
5.1.2 The baseline data described in Chapter 4 were used to assign a level of sensitivity to various parts of the study area, as described in section 4.3. The levels of sensitivity fed into a process of environmental analysis relating to each of the identified connection options.
5.1.3 This section summarises the findings of the environmental analysis of the connection options, as well as providing a summary of the preferred connection option.
5.2 Environmental Analysis of Connection Options Lattice Steel Tower 132 kV OHL
5.2.1 The preferred route (shown as Option 1A on Figure 2) was identified as the least environmentally constrained route option for the installation of a lattice steel tower 132 kV OHL. This was based on the following environmental analysis:
The alignment followed by the preferred route was considered preferable in the area between the proposed Thurso South substation and the Hill of Olrig. Although a number of potentially significant constraints were identified, (particularly relating to landscape and visual amenity, as well as land use and landowner preferences) this alignment provides the opportunity to avoid the attractive and small scale area of agricultural landscape around Mayfield; it also offers an opportunity to avoid sensitive ecology associated with a potential area of GWDTE at Bullimore.
Between the Hill of Olrig and Wester Olrig Cottages the preferred route was selected in landscape and visual amenity terms as well as when considered against archaeology and cultural heritage interests, recreational interests and in terms of agricultural land and indicative landowner preferences. However, the environment is considered to be of high sensitivity and a number of potentially significant constraints were identified affecting all of the route options for lattice steel towers (ecological and ornithological constraints) in this section.
Between Wester Olrig Cottages and Greenland, a preference was identified for Option 3 in landscape and visual terms as well as when considered against archaeology and cultural heritage interests and against recreational interests. However, potentially significant ornithological constraints were identified affecting all route options through this section.
From Greenland through to the proposed Gills Bay substation a clear preference was identified in terms of ecology, ornithology, landscape, visual amenity, recreation, archaeology and cultural heritage, and land use.
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Twin Trident (woodpole) 132 kV OHL
5.2.2 The preferred route (shown as Option 1A on Figure 2) was also identified as the least environmental constrained route option for the installation of a twin Trident woodpole structure, based on the following environmental analysis:
As above, the alignment followed by the preferred route in the area between the proposed Thurso South substation and the Hill of Olrig was considered preferable in landscape terms as it provides the opportunity to avoid the attractive and small scale area of agricultural landscape around Mayfield. Although a number of potentially significant constraints were identified with all of the route options, it was also considered that the ecological benefit brought about by the alignment of the preferred route away from the corner of a potential GWDTE at Bullimore was sufficient to weigh the balance in favour of the alignment of the preferred route.
Between the Hill of Olrig and Wester Olrig Cottages, potentially significant constraints were identified affecting all the route options. The preferred route was selected in landscape and visual amenity terms, as well as when considered against archaeology and cultural heritage interests, recreational interests and in terms of agricultural land and indicative landowner preferences.
Between Wester Olrig Cottages and Greenland, a preference was identified for Option 3 in landscape and visual terms as well as when considered against ecology, archaeology and cultural heritage interests and against recreational interests. However, potentially significant ornithological constraints were identified affecting all route options through this section.
From Greenland through to the proposed Gills Bay substation a clear preference for the preferred route was identified in terms of ecology, ornithology, landscape, visual amenity, recreation, archaeology and cultural heritage, and land use.
5.3 Comparison of Lattice Steel tower and Twin Trident (woodpole) supports
5.3.1 Following the environmental analysis above, route Option 1A was identified as the most appropriate route option for either conductor support type. A subsequent comparison was then completed of whether the preferred route could better accommodate lattice steel towers or twin Trident woodpoles.
5.3.2 The comparison of conductor support type was based on the following key design assumptions7:
7 These parameters are illustrative only and do not constitute a design commitment at this stage.
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Table 5.1: Key Design Parameters Parameter Lattice Steel Tower double Twin Trident double circuit H circuit 132 kV OHL pole 132 kV OHL Standard Height (Max Height) 26 m (40 m) 13 m Width of Wayleave required 70 m 70 m Span Length 250 m 110 m Construction Footprint per 50 m x 50 m (2,500 m2) 20 m x 20 m (400 m2) pole/tower Estimated no of poles/towers 90 to 100 towers 420 to 460 double poles 8
5.3.3 A lattice steel tower configuration was considered preferable, based on the following analysis:
Between Thurso South substation and the Hill of Olrig, no differentiator between conductor support types was identified in terms of ornithology and recreation and tourism. Lattice steel towers were anticipated to have less effect on landscape, visual amenity and archaeology and cultural heritage interests. Lattice steel towers were also preferred in terms of land use and potential to affect agricultural land and farming patterns. By contrast, a twin Trident woodpole configuration was anticipated to result in less direct impact on sensitive ecological habitats. A preference was also identified for a twin, Trident woodpole configuration in terms of geology, hydrology and hydrogeology, due to the shallower, less extensive and less intrusive foundation requirements, particularly in areas with shallow groundwater and areas of potential GWDTE. On balance, a lattice steel tower configuration was considered preferable along this part of the route.
Between the Hill of Olrig and Wester Olrig Cottages, no differentiator between conductor support types was identified in terms of ornithology, archaeology and cultural heritage and recreation and tourism. Lattice steel towers were anticipated to have less impact in terms of land use and potential to affect agricultural land and farming patterns. In addition, although lattice steel towers were anticipated to have a greater direct footprint impact on sensitive habitats (GWDTE), a tower configuration would provide the opportunity to span over the designated habitat associated with the Loch of Durran SSSI. By contrast, a twin Trident woodpole configuration was anticipated to have less impact on visual amenity. A preference was also identified for a twin Trident woodpole configuration in terms of geology, hydrology and hydrogeology, due to the shallower, less extensive and intrusive foundation requirements, particularly in areas with shallow groundwater and areas of potential GWDTE. Overall, it was considered that the potential opportunity to avoid direct impact on the designated Loch of Durran SSSI offered by the longer span length of the lattice steel tower, and the potential for less disruption to farming activity and
8 210 to 230 double poles per circuit. With two circuits in parallel this will require 420 to 460 double poles (H pole configuration)
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practices, supports the preference for lattice steel towers.
Between Wester Olrig and Greenland, each configuration would interact differently with the environmental setting. In terms of ecology, a larger area of habitat, particularly habitat identified as potential GWDTE, was estimated to be affected by steel lattice towers than by Trident wood poles. However, a steel lattice tower configuration was anticipated to have a direct effect on the Earney Hillock chambered cairn than a Trident woodpole configuration. A preference was identified for a twin Trident woodpole configuration in terms of geology, hydrology and hydrogeology, due to the shallower, less extensive and intrusive foundation requirements, particularly in areas with shallow groundwater and areas of potential GWDTE. However, a preference for lattice steel towers was identified in terms of land use and potential to affect agricultural land and farming patterns. Therefore, no strong preference for either configuration was identified.
From Greenland to the proposed Gills Bay substation, a larger area of habitat, particularly habitat identified as potential GWDTE, was estimated to be potentially affected by steel lattice towers than by Trident woodpoles. However, it was considered that lattice steel towers could have a lesser effect in terms of bird collision risk as a lattice steel tower configuration would result in a vertical configuration of wires, with less potential effect on known low level bird activity. Interaction with bird activity would however require careful consideration for either option. In addition, a lattice steel tower configuration might be expected to interact less with the proposed wind farms in this area and would be preferred in landscape terms.
Overall, a lattice steel tower was considered preferable in this part of the study area.
5.3.4 The analysis summarised above shows that, although clear preferences exist relating to each individual environmental topic, a balance of considerations must be reached and a lattice steel tower configuration would be preferable between Thurso South substation and Wester Olrig cottages, and also between Greenland and Gills Bay substation. No clear preference exists between Wester Olrig and Greenland.
5.3.5 An overall preference for a lattice steel tower configuration has therefore been identified along the preferred route.
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6 THE PROPOSALS
6.1 Draft Limits of Deviation
6.1.1 Following identification of the preferred connection option, indicative draft Limits of Deviation (LOD) have been developed which describe the horizontal area in which the preferred connection option would be developed and will eventually define the s37 area in which the final Proposed Development would be constructed9.
6.1.2 The proposed horizontal dimensions of the LOD are shown on Figure 4. A vertical height of 40 m applies for the full length of the LOD at this stage.
6.1.3 In developing the indicative LOD, consideration was given to the following principles:
Presumption towards the narrowest possible LODs whilst providing engineering flexibility for future construction micro-siting;
Presumption towards avoiding sensitive environmental features;
Presumption towards avoiding residential properties, allowing a 100 m buffer where possible; and
Where sensitive environmental receptors cannot be avoided, such as in the case of potential GWDTE (marshy grassland) habitat, the LOD provide sufficient flexibility for micro-siting to avoid and/or minimise any impact.
6.2 Line Design and Construction Typical Tower Design
6.2.1 As with the majority of high voltage OHL in the United Kingdom, the proposed 132 kV OHL between Thurso South substation and the new Gills Bay substation would be constructed using self-supporting lattice steel towers.
6.2.2 Lattice steel towers would vary in height to accommodate changes in topography and where the line crosses roads and rivers, although the standard height would generally be in the region of approximately 26 m up to a maximum of 40 m.
6.2.3 Figure 5 below illustrates the type of tower which may be used.
6.2.4 The spacing between towers would vary depending on topography, altitude and land usage. The height and distance between towers will be determined later in the design process; however an average span of 250 m is estimated.
9 Note that this does not include an allowance for areas in which construction activity, access tracks etc. will be required.
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Figure 5: Key Characteristics of the Proposed Towers
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High voltage OHL Construction
6.2.5 High voltage OHL construction typically follows a standard sequence of events as follows:
complete pre-construction surveys, as required by a construction environmental management plan;
establish access (including any necessary vegetation management);
install tower foundations;
assemble and erect towers;
erect temporary scaffolds and protection to roads, railways and rivers;
string conductors (wires);
dismantle and remove temporary scaffolds and protection; and
re-instate tower sites and remove temporary access tracks. Access Strategy
6.2.6 Temporary tracks capable of taking a crane and other heavy plant, including concrete deliveries, are generally required for the construction of a tower. Where ground conditions permit, it is preferable to construct the towers without an access track (e.g. on dry and level pasture). Matting may be used in some sensitive areas subject to an assessment of gradients and ground conditions.
6.2.7 Tracks would generally be constructed using a geotextile, with approximately 200 mm of crushed and compact stone laid on top. Tracks may be floated over areas of peat, or may use cut and fill approaches, subject to ground conditions and gradients. It is likely that, for most of the route, a temporary track would be established along the route, with access back to the local road network at intermittent locations.
6.2.8 The requirement for permanent access tracks will be minimised. Permanent tracks will only be considered where access will be required for maintenance once the OHL is operational.
6.2.9 Temporary construction compounds would also be required along the route, the location of which will be determined through further on-going design works. Foundation installation
6.2.10 A tower compound would be established at each tower location, within which foundation installation and subsequent tower erection would take place. Each compound would be fenced for safety reasons. There are three different types of foundations available:
Spread type e.g. pad and chimney and pyramid and chimney;
Piled type e.g. tube, augured shaft and micro pile; or
Rock anchor.
6.2.11 The majority of the foundations would likely be of a spread type. However, depending on particular ground conditions, there may be the requirement to use mini-piled, auger or rock anchor foundations. Foundation types and designs for
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each tower would be confirmed following detailed geotechnical investigation at each tower position.
6.2.12 For the majority of towers using spread type foundations, excavations are advanced for each leg of the tower. The size of excavation would vary according to the foundation design; however excavations are typically 3-4 m deep, with excavation carried out by mechanical excavator, and rock breaking required in some locations. The foundation stub is then concreted into position using the foundation formwork.
6.2.13 After the concrete has cured, the excavations can be backfilled using the excavated materials. Tower Assembly and Erection
6.2.14 Tower steelwork is generally delivered to site either as individual steel members or as prefabricated panels, dependent on the method of erection for the tower.
6.2.15 If the access is suitable, a crane would be used to complete the assembly and erection of the tower. If there is no vehicular access or it is unsuitable for a crane then a helicopter would be used to deliver an erection derrick, winch and ancillary equipment to site to effect the tower erection. Conductor Stringing
6.2.16 Prior to stringing the conductors, temporary protection measures (normally netted scaffolds), would be erected if necessary for features such as roads, railways and existing transmission infrastructure to be crossed. The heavy plant and equipment required, including heavy towing tractors, winches, tensioners, pilot reels and conductor drums would be taken to the conductor stringing machine sites along the ground using a mixture of low-loaders and 4x4/6x6 'Hiab' crane lorries.
6.2.17 Conductor stringing equipment i.e. winches, tensioners and ancillary equipment, is generally set up at either end of pre-selected sections of the OHL. Firstly, pilot wires are pulled through the section to be strung. The pilot wires are hung in blocks (wheels) at each suspension tower in the section and connected to a winch and tensioner at the respective end of the section. The winch in conjunction with the tensioner is used to pull the pilot wires which are connected to the conductor at the tensioner end. The conductor is pulled via the pilot wires through the section and under controlled tension to avoid contact with the ground and any under-running obstacles including protection scaffolds. Once the conductor has been strung between the ends of the section it is then tensioned to provide the necessary sag and then permanently clamped at each tower. Construction programme
6.2.18 It is anticipated that the construction programme would last approximately 18 months. A notional start date in July 2015 would allow the completion of construction by December 2016. The detailed construction phasing and programme will be subject to change as the design progresses and also due to necessary consents and wayleaves being agreed.
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7 CONSULTATION ON THE PROPOSALS
7.1 The Proposals
7.1.1 As described in Chapter 5, the proposals have been developed through a detailed environmental analysis of various route options, followed by an environmental analysis of potential impacts from different conductor support types.
7.1.2 The preferred connection option which has been identified extends from the proposed new Thurso South substation near Geiselittle to a proposed new substation south of Gills Bay (Philips Mains), via the south side of the Hill of Olrig and Moss of Greenland, and comprises a lattice steel tower structure.
7.1.3 The potential for significant environmental effects remains, and the EIA and design process will be important in giving detailed consideration to the development and integration of mitigation measures to address potentially significant environmental effects which have been identified.
7.2 Questions for Consideration by Consultees
7.2.1 When providing comment and feedback, SHE Transmission would be grateful for your consideration of the questions below:
Is the rationale for the project clearly set out in the Consultation Document?
Is the approach to the selection of the preferred connection option, identifying the optimum balance of technical, economic and environmental feasibility, clearly set out?
Are there any factors you consider may have been overlooked or given either insufficient or too much consideration during the selection process?
Do you have any other comments about the preferred route?
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Annex A: Figures Figure 1: Study Area Figure 2: Connection Options Considered Figures 3a and 3b: Environmental Constraints Figure 4: Preferred route with Limits of Deviation (LOD) Figure 5: Typical Steel Lattice Tower Design
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Annex B: Environmental Baseline Data Sources
ENVIRON UK Ltd (July 2011) Caithness Reinforcements: Preliminary Environmental Appraisal and Proposed Scope and Methods of Further Survey
Highland Archaeology Services Ltd (August 2011) Caithness Electricity Distribution Reinforcement – Dounreay - Gills Bay 132kV (Revised Route) Cultural Heritage Baseline Assessment
Highland Council planning portal: http://wam.highland.gov.uk/wam/
Historic Scotland website:
http://data.historic-scotland.gov.uk/pls/htmldb/f?p=2000:10:0:
Macaulay Land Use Research Institute (June 2010) Land Capability for Agriculture in Scotland map
Ordnance Survey mapping at 1:50,000 scale, 1:10,000 scale and 1:250,000 scale
SEPA Flood Risk mapping: http://www.sepa.org.uk/flooding/flood extent maps.aspx
SNH Sitelink website: http://gateway.snh.gov.uk/sitelink/index.jsp
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