We are testing a new beta website for gov.scot go to new site

Strategic Environmental Assessment (SEA) of Draft Plan for Offshore Wind Energy in Scottish Territorial Waters: Volume 1: Environmental Report

Listen

8 Assessment of Environmental Effects

8.1 Introduction

This chapter identifies the likely significant effects on the environment of the reasonable alternative options considered in Chapter 7 and the draft Plan for offshore wind development, both alone and in combination with other relevant plans and strategies. The assessment tests compliance of the options against the seven SEA objectives presented in Chapter 6.

Where a significant effect has been identified, this chapter also describes where further action is needed i.e. the measures envisaged to prevent, reduce and as fully as possible offset any identified significant negative effects. The methodologies used for this assessment are described in Section 8.2.

8.2 Assessment Methodologies

8.2.1 Overview

Section 2.7 describes the overall SEA assessment methodology.

Potential strategic impacts that are likely to arise from pre-construction, construction, operation and decommissioning activities associated with offshore wind development are listed in chapter 4. These potentially significant 'generic' impacts have been used to guide the assessment, and evaluate the significance of the short term alternative options, taking into account the various environmental constraints and sensitivities at each site.

The reasonable alternatives (i.e. to do nothing or to do maximum at each of the sites within the short term and medium term options) have been assessed against the range of environmental issues set out in Schedule 3 of the Environmental Assessment (Scotland) Act 2005.

Ten sites proposed by The Crown Estate for progressing offshore wind (and where it is proposed to grant commercial leases subject to successfully meeting the consenting requirements) have been considered as alternatives for assessment in the short term (see Section 7.3 and Figure 7.1).

The impact assessments of each of the 10 short term options and the 30 medium term options identified in each of the six regions are presented in tables in Appendices 8.2 and 8.3.

Table 8-1 is the key to 'significance' values used and Table 8-2 summarises and compares the strategic environmental impacts of the alternative options under consideration.

8.2.2 Impact Assessment Procedure

The following procedure was used to assess and evaluate the environmental impacts of the alternative options considered as part of this SEA:

  • overlay of the option onto the baseline information;
  • identification of environmental receptors affected by the option; and
  • identification and assessment of the nature (positive, negative or neutral) of the potential effects and significance of the impact using Table 8-1, applying the SEA objective to each alternative option.

Table 8-1: Key to Potential Significance of Alternative Options Assessment

Symbol

Impact Significance

Description of Impact Significance

Moderate to Major Positive

Moderate to Major Positive

The option would significantly benefit the SEA objective by resolving an existing environmental issue and/or maximising opportunities for environmental enhancement

Minor Positive

Minor Positive

The option would be partially beneficial to the SEA objective by contributing to resolving an existing environmental issue and/or offering opportunity for some environmental enhancement

Neutral

Neutral

The option would not significantly affect the SEA objective

Uncertain

Uncertain

There is insufficient detail available on the option or receptor in order to assess how significantly the SEA objective would be affected by the option. Where uncertainty is identified, an assessment of the significance is not possible without further survey work or scheme level detail.

Minor Negative

Minor Negative

The option would partially undermine the SEA objective by contributing to an environmental problem and/or partially undermine opportunities for environmental enhancement

Moderate to Major Negative

Moderate to Major Negative

The option would severely undermine the SEA objective by creating an environmental problem and/or undermine opportunities for environmental enhancement

In addition to the impact significance criteria defined above, it was considered that there were additional benefits in differentiating between moderate and major impacts for the landscape and visual amenity receptor (see Appendix 8.1 for assessment methodology).

Moderate change (Landscape and visual)

Moderate change (Landscape and visual)

This option would result in a moderate change in landscape or visual amenity.

Impact significance is the product of the sensitivity of the receptor and the magnitude and nature of the change. In determining significance, the precautionary principle has been applied.

Those impacts that have been identified as 'neutral' during the assessment are not considered significant.

In addition to the impact significance criteria defined in Table 8.1, it was considered that there were additional benefits in differentiating between moderate and major impacts for the landscape and visual amenity receptor (see Appendix 8.1 for assessment methodology).

For some SEA receptors, specific assessment methodologies have been devised to enable assessment of the SEA objective. These are described in detail together with the assumptions made during the assessment in Appendix 8.1.

  • consideration of the reversibility of the potential effect on the receptor:
    • a reversible effect (R) is an environmental effect that can be reversed, for example an incident of water pollution can be cleaned up over time.
    • an irreversible effect (I) is an environmental effect that cannot be reversed such as the loss of a historic feature.
  • consideration of the duration of the potential effect:
    • a permanent effect (P) is one which results from a physical change that is anticipated to last beyond the life of the development.
    • a temporary/intermittent (T) effect is one which results from an operational change which could change if there is a change of policy, or a short term condition such as a construction phase related impact.
  • consideration of the spatial scale:
    • local (L): effect is restricted to the immediate location of the development sites
    • regional (R): effect is anticipated to be limited to the assessment area (i.e. west, north west, north, north east, east, south east)
    • national (N): effect covers the whole of Scotland and/or the UK.
    • international (I): effect is anticipated to affect assets of international importance.
  • where potentially significant effects were identified, establishment of appropriate mitigation and enhancement measures needed to ameliorate or reduce potential strategic impacts to an acceptable level.

The source and pathway of potential impacts relevant to offshore wind farms in general on the various SEA receptors are described in Chapter 4, where consideration has been given to the various stages of a development when an impact may occur i.e. during construction, whilst operating and during decommissioning.

8.3 Evolution of Baseline in the Absence of the Plan

The likely evolution of the baseline in the absence of the Plan is summarised below: -

  • there would be a continuation of existing coastal processes, hydrodynamics and sediment regime and any change in the existing environmental resource would be as a result of existing processes; and
  • no contribution to the wider energy and climate change objectives, with increasing reliance on fossil fuel combustion and alternative renewable energy sources such as onshore wind, tidal, solar, geothermal and wave energy.

The Environmental Assessment (Scotland) Act 2005 requires that the evolution of the study area in the absence of the Plan is considered. This scenario therefore provides a baseline against which the impacts of the alternative options can be compared and the need for a Plan can be identified.

8.4 Assessment of Short Term Options

Table 1 in Appendix 8.2 presents the full impact assessment of each of the individual ten short term options. These describe the SEA environmental receptors at risk within the ten sites, the potentially significant environmental impacts of these short term options (including the potential cumulative impacts associated with them), mitigation measures and the residual impacts following mitigation.

Table 8-2 summarises the potential impacts (both significant and non-significant) of the ten short term sites prior to mitigation.

Table 8-2: Potentially Significant Impacts of Alternative Options (Prior to Mitigation)

OPTION

Area (km2)

Climatic Factors

Water

Geology Sediments & Coastal Processes

Biodiversity, Flora & Fauna

Landscape & Visual Amenity

Population & Human Health

Cultural Heritage

Material Assets

Natura 2000 & National Sites

European Protected Species

Wildlife

Seascape Character

Internationally/ nationally designated landscapes

Visual Amenity

RYA Cruising/ Sailing Areas

Marine & Coastal Recreation

Designated sites or features & military remains

Navigation and Anchorage

Absence of Plan

N/A

Moderate to Major NegativeNeutralNeutralNeutralNeutralNeutralNeutralNeutralNeutralNeutralNeutralNeutralNeutral

Short Term Options

Beatrice

121

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeMinor NegativeNeutralMinor NegativeMinor NegativeNeutralNeutralMinor Negative

Inch Cape

150

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate change (Landscape and visual)NeutralMinor NegativeNeutralMinor NegativeNeutralModerate to Major Negative

Bell Rock

93

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate change (Landscape and visual)NeutralModerate change (Landscape and visual)Minor NegativeMinor NegativeNeutralModerate to Major Negative

Neart na Gaoithe

105

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate change (Landscape and visual)NeutralMinor NegativeMinor NegativeModerate to Major NegativeModerate to Major NegativeModerate to Major Negative

Forth Array

128

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate change (Landscape and visual)Minor NegativeMinor NegativeMinor NegativeNeutralNeutralModerate to Major Negative

Solway Firth

61

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

Wigtown Bay

51

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralMinor Negative

Kintyre

69

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

Islay

95

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate to Major NegativeMinor NegativeMinor NegativeNeutralModerate to Major NegativeNeutralModerate to Major Negative

Argyll Array

361

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major NegativeModerate to Major NegativeModerate to Major Negative

Key

Symbol

Impact Significance

Moderate to Major Positive

Moderate to Major Positive

Minor Positive

Minor Positive

Neutral

Neutral

Uncertain

Uncertain

Minor Negative

Minor Negative

Moderate to Major Negative

Moderate to Major Negative

Symbol

Impact Significance

Moderate change (Landscape and visual)

Moderate change (relates to landscape and visual amenity only)

A summary of the potentially significant environmental impacts that may result from all short term options (prior to mitigation) is provided below, and is followed by a list of more 'site specific' impacts that may be experienced at each of the individual 10 sites:

All short term options

  • major beneficial impacts on climate, reducing greenhouse gas emissions and Scotland's carbon footprint, and will contribute to future renewable energy targets. These are global and permanent solutions to managing climate change, and its associated effects on the environment. Conventional energy production has a construction and decommissioning carbon cost, which would be reduced as a result of developing offshore wind farms and, in the case of carbon-based fuel, the carbon cost is ongoing.
  • potential changes to coastal processes and sediment circulation/dispersion, which may affect (positively or negatively) geomorphological features, nationally designated coastal geological sites in parts of the STW and the existing good or excellent water quality. Any changes in water quality, predominantly during the construction stage, have the potential to indirectly affect wildlife dependent on existing water conditions and parameters, and the ability of fish species to spawn, respire and feed.

Any potential adverse impacts on shellfish growing waters through changes in sediment dispersion and deposition would predominantly occur during construction and decommissioning at sites in the east of Scotland (e.g. Bell Rock, Inch Cape, Neart na Gaoithe and Forth Array) and west of Scotland (e.g. Argyll Array, Islay and Kintyre) where shellfish waters are prevalent.

Effects on water quality resulting from the introduction of turbines will last for the duration of their presence and some will be reversible.

The significance of these impacts is currently uncertain (see Table 9-1).

  • beneficial impacts on biodiversity including the creation of artificial habitat for marine organisms and new fish spawning and nursery areas, resulting from the presence of new structures. In addition, the lack of commercial fishing (e.g. trawling) in areas where wind farms are sited may enhance biodiversity. The permanence of these potentially beneficial effects has to be considered in terms of the life of the infrastructure (and artificial habitat and ecological assemblages), which may be removed during decommissioning.
  • potential for adverse effects on nature conservation including marine mammals, birds, benthic ecology and fish during construction, operation and decommissioning though many of the impacts remain uncertain due to our limited understanding of the sensitivity, distribution and behaviour of these species e.g. to noise/vibration generating activities (see Table 9-1 for further work recommended). It is anticipated that adverse impacts may result from the displacement/disturbance of birds, mammals, fish, benthic communities and flora through a combination of factors including noise, vibration, visual and light intensity changes, water quality changes, habitat disturbance and/or the presence of structures and vessels. Additional cumulative impacts may occur, particularly affecting mammals and migratory fish from an increased number of barriers affecting fish movement, multiple noise sources audible to marine mammals and fish during construction and increased vessel disturbance. It is anticipated that many of the construction and decommissioning effects may be temporary and reversible. However, some impacts on biodiversity experienced during operation of wind farms are likely to be permanent and irreversible.
  • potential for significant impacts on international (and national) nature conservation sites; these will be considered further within a Habitats Regulations Appraisal.
  • direct adverse affects on benthic habitat (potentially including sub-littoral BAP habitats, sabellaria reefs) and associated species, although the importance of subtidal biotopes is uncertain without further survey work at project level.
  • temporary changes in landscape and visual amenity during construction as a result of the presence of delivery vessels and construction works associated with building new infrastructure. However, the majority of strategic impacts (e.g. from the introduction of new wind turbines) will result in permanent changes in landscape and visual amenity during the operation of the wind farms.

The greatest permanent impacts on seascape character are likely to occur at sites in the west of Scotland (Islay, Kintyre, Argyll Array) and the south-west (Solway Firth and Wigtown Bay) due to the presence of new offshore wind structures in medium-high and high sensitivity seascapes, which are sensitive to development. These options (except Islay) would also have major visual impacts due to their proximity to land. Solway Firth and Wigtown Bay may also experience cumulative landscape and visual impacts due to their proximity to the Robin Rigg wind farm and their potential for major adverse impacts on nationally designated coastal landscapes.

  • provision of a new renewable energy supply for the projected increase in the Scottish population. This beneficial impact will be experienced throughout the life of an operating wind farm.
  • potential significant adverse impacts (including cumulative impacts) on recreation resulting from the short term options are likely to occur in and around the Firths, where recreational activity is greatest. Potentially adverse effects identified on recreation from all short term options include disturbance during construction to, or loss of, coastal and marine recreational areas (including light or moderately used RYA cruising/sailing routes) and activities during operation of a wind farm. There would be associated effects on the enjoyment and potentially the safety of marine users.

Only Beatrice and Forth Array lie outside areas identified by SNH (2007) to be of great importance for recreation.

  • potential adverse effects on unknown, submerged or non-designated archaeological features (including non-designated wrecks) or palaeo-landscapes, which may be present within their footprint, and therefore have the potential to be affected by construction.
  • potential adverse effects on navigation and shipping during construction and operation of offshore wind developments (see Table 9-1). However, it is assumed that the Maritime and Coastguard Agency and the Northern Lighthouse Board will only allow development that is considered safe and therefore it is likely that this issue will be considered further at the appropriate stage.

A summary of the potentially significant environmental impacts that may result from each specific short term option is provided below.

Beatrice

  • potentially adverse impacts on marine mammals that are known to occur around the waters of Beatrice including a resident population of bottlenose dolphins in the Moray Firth (that use areas further south), common and grey seals along the adjacent coasts of Morayshire and Caithness, harbour porpoise and various species of dolphin and whale. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impact on birds including internationally important resident, breeding and migratory birds (including divers, seaduck, gannets, swans and geese) that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on cod, plaice, lemon sole and sandeel spawning grounds and herring, whiting, saithe and sandeel nursery areas, which will be permanently affected by the footprint of the works and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • minor changes in views for land-based receptors (which lie a minimum of 13km away) through changes in the physical elements of the seascape and minor adverse impacts on East Caithness and Sunderland seascape.

Inch Cape

  • potentially adverse impacts on marine mammals that are known to occur around the waters of Inch Cape including a population of bottlenose dolphins resident in the Moray Firth (that use areas further south). These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds including internationally important resident, breeding and migratory birds (including divers, seaduck, gannets, swans and geese) that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on mackerel, plaice, whiting and sandeel spawning grounds and plaice, cod, whiting, saithe and sandeel nursery areas that will be permanently affected by the footprint of the works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • minor changes in view for land-based receptors that lie a minimum of 13km away, minor adverse impacts on a low to medium sensitivity seascape off the north east coast and moderate adverse impacts on a medium sensitivity seascape off east Fife/Forth of Tay.
  • adverse impacts on shipping routes associated with access to the ports of the Firths of Forth and Tay.

Bell Rock

  • potentially adverse impacts on marine mammals that are known to occur around the waters of Bell Rock including a population of bottlenose dolphins resident in the Moray Firth (that use areas further south). These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds within Important Bird Areas to the west of the site, which support large numbers of wintering waders and wildfowl and internationally important breeding seabirds (including divers, seaduck, gannets, swans and geese) that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on plaice, whiting, lemon sole and sandeel spawning grounds and plaice, cod, whiting, saithe and sandeel nursery areas that will be permanently affected by the footprint of the works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • moderate adverse impacts on seascape/landscape character and a minor change in visual amenity due to its proximity to land (land-based receptors lie a minimum of 13km away) and the medium sensitivity seascape of Fife/Forth of Tay.
  • potential adverse impact on the setting of Bell Rock Lighthouse, which occupies Bell Rock reef; this is the world's second oldest lighthouse and an A-Listed Building.
  • adverse impacts on shipping routes associated with access to the ports of the Firths of Forth and Tay.

Neart na Gaoithe

  • potentially adverse impacts on marine mammals that are known to occur around the waters of Neart na Gaoithe including a population of bottlenose dolphins resident in the Moray Firth (that use areas further south). These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds including internationally important resident, breeding and migratory birds (including divers, seaduck, gannets, swans and geese) that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on plaice, whiting, lemon sole and sandeel spawning grounds and cod, whiting, saithe, nephrops, lemon sole and sandeel nursery areas that will be permanently affected by the footprint of the works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. As with the previous two options, it should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • moderate adverse impacts on seascape/landscape character due to the presence of the medium sensitivity seascapes of East Fife/Forth of Tay and Forth of Forth.
  • adverse impacts on shipping routes associated with access to the ports of the Firths of Forth and Tay.

Forth Array

  • potentially adverse impacts on marine mammals that are known to occur around the waters of Forth Array including a population of bottlenose dolphins resident in the Moray Firth (that use areas further south). These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds including internationally important resident, breeding and migratory birds (including divers, seaduck, gannets, swans and geese) that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on mackerel, whiting, plaice and sandeel spawning grounds and cod, whiting and sandeel nursery areas that will be permanently affected by the footprint of the works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. As before, it should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • moderate adverse impacts on seascape/landscape character due to the presence of Berwick-upon-Tweed low-medium sensitivity seascape
  • adverse impacts on shipping routes associated with access to the ports of the Firths of Forth and Tay.

Solway Firth

  • potentially adverse impacts on marine mammals, which may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds including wintering wildfowl and waders in adjacent international nature conservation sites and Upper Solway Flats and Marshes Important Bird Area that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on sole and whiting spawning grounds and herring and whiting nursery areas that will be permanently affected by the footprint of the works in this area. These areas, together with cockle, mussel and winkle fisheries on the Solway shores, could be adversely impacted upon by changes in sediment deposition and turbidity. As before, it should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • major visual and seascape impacts due to its proximity to land (6.7km away), the high sensitivity seascape of the Outer Solway and nationally designated landscapes (including two NSAs and the Solway Coast AONB), and potentially cumulative impacts (notably visual) associated with the Robin Rigg windfarm, which borders the north-eastern boundary of the site.

Wigtown Bay

  • potentially adverse impacts on marine mammals, which may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds including wintering wildfowl and waders in adjacent international nature conservation sites and Important Bird Areas in the Solway Firth that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on whiting spawning grounds and herring, plaice and whiting nursery areas that will be permanently affected by the footprint of the works in this area. These areas, together with a Regulated Cockle Fishery area and mussel and winkle fisheries on the Solway shores, could be adversely impacted upon by changes in sediment deposition and turbidity. Again, it should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • major visual and seascape impacts due to its proximity to land (only 2.6km away), proximity to Fleet Valley NSA, and the presence of the high sensitivity seascape of Outer Solway.

Kintyre

  • potentially adverse impacts on marine mammals that are known to occur around the waters of Kintyre including harbour porpoise, white-beaked dolphin and grey and harbour seals. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds including wintering birds in the adjacent Machrihanish Important Bird Area to the east of the site and internationally important breeding seabirds off the Irish coastline, that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on saithe and cod nursery areas and sprat and nephrops spawning grounds in the footprint of the works and which could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • major visual and seascape impacts due to its proximity to land (only 0.9km away), high sensitivity seascape of West Kintyre and nationally designated landscapes (including three NSAs and two AONBs).

Islay

  • potentially adverse impacts on marine mammals, which may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds including several species of wintering geese that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on plaice spawning grounds and saithe and cod nursery areas in the footprint of the works. These could also be adversely affected by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • major changes in seascape due to the presence of the high sensitivity seascape of West Islay.

Argyll Array

  • Argyll Array would provide the greatest area for wind generation out of all of the short term options (and is sited in the west of Scotland where wind speeds are high), thus providing the greatest contribution to a reduction in greenhouse gases and a major beneficial impact.
  • potentially adverse impacts on marine mammals that are known to occur around the waters of Argyll Array including harbour porpoise, white-beaked dolphin and grey and harbour seals. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • potentially adverse impacts on birds including breeding storm petrel, auks and terns that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • direct adverse impact on sandeel, plaice and mackerel spawning grounds and saithe, sandeel, whiting and cod nursery areas in the footprint of the works. These could also be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds and consideration should be given to areas that may previously have been disturbed by other marine uses (e.g. trawling).
  • major visual and seascape impacts due to its proximity to land and a high sensitivity seascape of West Mull/East Tiree and West Coll/Tiree.
  • potential adverse impact on the setting of Skerryvore Lighthouse, an A-Listed Building, which lies within the boundary of this option.

The development of any of the short term options will require extensive consultation on any particular constraint identified, and they will require investigation on their own merits.

Screening for HRA has identified that all of the short term options have potential to affect designated international nature conservation sites and strategic HRA is therefore recommended for all options taken forward (i.e. 'The Plan'). The results of a full HRA will be required to identify whether adverse affects on international nature conservation sites are likely, and whether alternative offshore wind sites should be sought.

As there are many data limitations and uncertainties regarding environmental impacts at this strategic level, further work is required in relation to the development of any short term options (see Section 8.8).

8.5 Assessment of Medium Term Options

A description of the medium term options is provided in Chapter 7 and these are shown on Figure 7.2.

Tables 1- 6 in Appendix 8.3 present the impact assessment of each of the medium term options within the six areas. These tables describe the environmental receptors in each of the assessment areas, the potentially significant impacts on SEA receptors of these medium term options and the potential cumulative impacts associated with them.

Table 8-3 summarises the potential impacts (both significant and non-significant) of the medium term options prior to mitigation.

Table 8-3: Potentially Significant Impacts of Alternative Medium Term Options (Prior to Mitigation)

OPTION

Area (km2)

Climatic Factors

Water

Geology Sediments & Coastal Processes

Biodiversity, Flora & Fauna

Landscape & Visual Amenity

Population & Human Health

Cultural Heritage

Material Assets

Natura 2000 & National Sites

European Protected Species

Wildlife

Seascape Character

Internationally/ nationally designated landscapes

Visual Amenity

RYA Cruising/ Sailing Areas

Marine & Coastal Recreation

Designated sites or features & military remains

Navigation and Anchorage

Medium Term Options

W1

1491

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major NegativeNeutralModerate to Major Negative

W2

1039

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate to Major NegativeMinor NegativeMinor NegativeNeutralModerate to Major NegativeUncertainModerate to Major Negative

W3

57

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major NegativeNeutralModerate to Major Negative

W4

253

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate change (Landscape and visual)Minor NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

SW1

7

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate change (Landscape and visual)Minor NegativeMinor NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

SW2

93

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeNeutralMinor NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

SW3

354

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

SW4

24

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate change (Landscape and visual)Minor NegativeModerate to Major NegativeNeutralMinor Negative

SW5

55

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate change (Landscape and visual)Minor NegativeModerate to Major NegativeNeutralMinor Negative

SW6

16

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeMinor NegativeMinor NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

N1

1671

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Minor NegativeMinor NegativeUncertainNeutralUncertainMinor Negative

N2

449

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Minor NegativeModerate change (Landscape and visual)UncertainUncertainUncertainModerate to Major Negative

N3

1535

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Moderate change (Landscape and visual)Moderate to Major NegativeMinor NegativeNeutralUncertainModerate to Major Negative

N4

776

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Moderate change (Landscape and visual)UncertainNeutralNeutralMinor Negative

N5

1079

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Moderate to Major NegativeUncertainNeutralNeutralMinor Negative

N6

222

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeMinor NegativeModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Moderate to Major NegativeUncertainNeutralNeutralMinor Negative

N7

1729

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Moderate change (Landscape and visual)UncertainNeutralModerate to Major NegativeMinor Negative

N8

300

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeMinor NegativeModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate change (Landscape and visual)UncertainNeutralNeutralMinor Negative

E1

2022

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate change (Landscape and visual)Moderate to Major NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeUncertainModerate to Major Negative

NW1

206

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainMinor NegativeModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Minor NegativeNeutralModerate to Major NegativeMinor Negative

NW2

1278

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeMinor NegativeMinor NegativeNeutralModerate to Major Negative

NW3

277

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Minor NegativeMinor NegativeMinor NegativeModerate to Major NegativeModerate to Major Negative

NW4

156

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeMinor NegativeMinor NegativeMinor NegativeMinor NegativeNeutralMinor Negative

NW5

324

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Moderate to Major NegativeModerate to Major NegativeMinor NegativeNeutralModerate to Major Negative

NW6

914

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Moderate to Major NegativeModerate to Major NegativeMinor NegativeNeutralModerate to Major Negative

NW7

2554

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Moderate to Major NegativeMinor NegativeMinor NegativeNeutralMinor Negative

NW8

2531

Moderate to Major PositiveUncertainUncertainModerate to Major NegativeUncertainModerate to Major NegativeModerate to Major NegativeNeutralNeutralMinor NegativeNeutralNeutralMinor Negative

NE1

387

Moderate to Major PositiveUncertainUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)Minor NegativeModerate to Major NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

NE2

170

Moderate to Major PositiveUncertainUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)NeutralModerate change (Landscape and visual)Minor NegativeModerate to Major NegativeNeutralModerate to Major Negative

NE3

131

Moderate to Major PositiveUncertainUncertainUncertainModerate to Major NegativeModerate to Major NegativeModerate change (Landscape and visual)NeutralMinor NegativeMinor NegativeModerate to Major NegativeNeutralModerate to Major Negative

A summary of the potentially significant environmental impacts that may result from all medium term options (prior to mitigation) is provided below, and is followed by a list of more 'site specific' impacts that may be experienced in each of the six areas:

  • major beneficial impacts on climate, reducing greenhouse emissions and Scotland's carbon footprint, and will contribute to future renewable energy targets. These are global and permanent solutions to managing climate change, and its associated effects on the environment. Conventional energy production has a construction and decommissioning carbon cost, which would be reduced as a result of developing offshore wind farms and, in the case of carbon-based fuel, the carbon cost is ongoing.
  • potential to result in changes to coastal processes and sediment circulation/dispersion, which may affect geomorphological features, nationally designated geological sites in parts of the STW and the existing good or excellent water quality. Any changes in water quality have the potential to affect wildlife dependent on existing water conditions and parameters, and the ability of fish species to spawn, respire and feed. Effects on water quality resulting from the introduction of turbines will last for the duration of their presence and some will be reversible.

All options have the potential to affect shellfish growing waters during construction and decommissioning of offshore wind farms.

The significance of these impacts is currently uncertain without further work (see Table 9-1).

  • beneficial impacts on biodiversity including the creation of artificial habitat for marine organisms and new fish spawning and nursery areas, resulting from the presence of new structures. In addition, the lack of commercial fishing (e.g. trawling) in areas where wind farms are sited may enhance biodiversity. The permanence of these potentially beneficial effects has to be considered in terms of the life of the infrastructure (and artificial habitat and ecological assemblages), which may be removed during decommissioning.
  • potential for adverse effects on nature conservation including marine mammals, birds, benthic ecology and fish during construction, operation and decommissioning, though many of the impacts remain uncertain due to our limited understanding of the sensitivity, distribution and behaviour of these species e.g. to noise/vibration generating activities (see Table 9-1 for further work recommended). It is anticipated that adverse impacts may result from the displacement/disturbance of birds, mammals, fish, benthic communities and flora through a combination of factors including noise, vibration, visual and light intensity changes, water quality changes, habitat disturbance and/or the presence of structures and vessels. Additional cumulative impacts may occur, particularly affecting mammals and migratory fish from an increased number of barriers affecting fish movement, multiple noise sources audible to marine mammals and fish during construction and increased vessel disturbance. It is anticipated that many of the construction and decommissioning effects may be temporary and reversible. However, some impacts on biodiversity experienced during operation of wind farms are likely to be permanent and irreversible.
  • direct adverse affects on benthic habitat (potentially including sub-littoral BAP habitats, sabellaria reefs) and associated species, although the importance of subtidal biotopes is uncertain without further survey work at project level.
  • temporary changes in landscape and visual amenity during construction as a result of the presence of delivery vessels and construction works associated with building new infrastructure. However, the majority of strategic impacts (e.g. from the introduction of new wind turbines), will result in permanent changes in landscape and visual amenity during the operation of the wind farms.
  • The greatest permanent impacts on seascape/landscape and visual amenity are likely to occur at NW5 and NW6 in the north west, due to the presence of high sensitivity seascapes, the proximity to land and the proximity to NSAs.

All medium term options (with the exception of E1, which lies in a low to medium sensitivity seascape), have the potential to affect medium or high sensitivity seascapes.

All medium term options (with the exception of SW2) have the potential to affect nationally designated landscapes.

  • provision of a new renewable energy supply for the projected increase in the Scottish population. This beneficial impact will be experienced throughout the life of an operating wind farm.
  • potential significant adverse impacts (including cumulative impacts) on recreation resulting from the medium term options are likely to occur in and around the Firths, where recreational activity is greatest. Potentially adverse effects identified on recreation from all medium term options include disturbance during construction to, or loss of, coastal and marine recreational areas (including light or moderately used RYA cruising/sailing routes) and activities during operation of a wind farm. There would be associated effects on the enjoyment and potentially the safety of marine users.

All medium term options (with the exception of options W1, W2 and W3) have the potential to significantly affect moderate or light use RYA cruising routes and/or sailing areas during construction, operation and decommissioning of an offshore wind development.

  • potential adverse effects on unknown, submerged or non-designated archaeological features (including non-designated wrecks) or palaeo-landscapes, which may be present within their footprint, and therefore have the potential to be affected by construction.
  • potential adverse effects on navigation and shipping during construction and upon operation of offshore wind developments (see Table 9-1). However, it is assumed that the Maritime and Coastguard Agency and the Northern Lighthouse Board will only allow development that is considered safe and therefore it is likely that this issue will be considered further through the evolution of development plans, which take into account shipping requirements.

A summary of the potentially significant environmental impacts that may arise in each region is provided below:

East Area

  • Potentially adverse impacts on marine mammals including cetaceans and seals. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • Potentially adverse impacts on birds including migratory and breeding birds that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • Direct adverse impact on spawning grounds and nursery areas (e.g. for cod, herring, whiting and saithe) for fish species that will be permanently affected by the footprint of works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds.
  • Major visual and seascape impacts due to proximity to land and nationally designated landscapes.

South West Area

  • Potentially adverse impacts on marine mammals including cetaceans and seals. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • Potentially adverse impacts on birds including migratory birds and internationally breeding birds off the Irish coastline and elsewhere (with the exception of SW2 and SW6 which do not lie offshore from SPAs designated for breeding birds) that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • Direct adverse impact on spawning grounds and nursery areas (e.g. for whiting) for fish species that will be permanently affected by the footprint of works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds.
  • Moderate or major seascape impacts due to the presence of medium and high sensitivity seascapes and nationally designated landscapes. However, SW1, 2 and 6 are considered to have the least visual impacts on coastal receptors. SW2 is the only option in the south west which would be unlikely to adversely affect a nationally designated landscape.

Based on the existing available data outlined in this SEA, the medium term option SW2 is considered to have the least strategic adverse impacts on the environment in comparison with the other medium term options.

West Area

  • Potentially adverse impacts on marine mammals including cetaceans and seals. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • Potentially adverse impacts on birds including migratory birds and breeding birds that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • Direct adverse impact on spawning grounds and nursery areas (e.g. for cod and saithe) for fish species that will be permanently affected by the footprint of works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds.
  • Moderate or major adverse impacts on seascape as all options lie within medium or high sensitivity seascapes that are sensitive to offshore wind development, and W1, W3 and W4 are likely to have significant visual impacts on coastal receptors due to the proximity to the coastline.

North West Area

  • Potentially adverse impacts on marine mammals including cetaceans and seals. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • Potentially adverse impacts on birds including migratory birds and breeding birds that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • Direct adverse impact on spawning grounds and nursery areas (e.g. for cod, mackerel, saithe and whiting) for fish species that will be permanently affected by the footprint of works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds.
  • Major adverse impacts on seascape as all options lie within medium-high or high sensitivity seascapes that are vulnerable to offshore wind development, and NW1 lies within 7km of St Kilda NSA and WHS. Visual amenity from Loch Druidibeg National Nature Reserve/ UNESCO Biosphere Reserve may also be affected by new offshore developments. NW8 is the only option to not adversely affect a nationally designated landscape or adversely impact on visual amenity.
  • Potential for high collision risk with ships using the Minch and the deep water shipping route west of the Outer Hebrides.
  • Potential for NW1 to have major adverse impacts on the Outstanding Universal Value of St. Kilda World Heritage Site, which lies within 7km of this option. Given the sensitivity of the seascape and environment in this area, it is recommended that this option is removed from the medium term plan at this stage.
  • Potential for NW3 to have major adverse impacts on the Outstanding Universal Value of St. Kilda World Heritage Site, through effects on the inter-relationship of St. Kilda and the Western Isles. Given the sensitivity of the environment in this area, it is recommended that this option is removed from the medium term plan at this stage.

North East Area

  • Potentially adverse impacts on marine mammals including cetaceans and seals. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • Potentially adverse impacts on birds including migratory birds and breeding birds that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • Direct adverse impacts on spawning grounds and nursery areas (e.g. for cod, herring, saithe and whiting) for fish species that will be permanently affected by the footprint of works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds. NE1, NE2 and NE3 are close to spawning grounds and nursery areas for several BAP marine fish species.
  • Moderate adverse impacts on medium sensitivity seascapes. NE1 lies only 3km from the coastline, thus major visual changes could be experienced by land-based receptors.

North Area

  • Potentially adverse impacts on marine mammals including cetaceans and seals. These species may be injured, displaced or disturbed by noise, vibration, increased vessel movements and electromagnetic field effects throughout the lifecycle of the wind farm or injured through collision with vessels or new structures.
  • Potentially adverse impacts on birds including migratory birds and breeding birds that may be displaced through a loss of feeding habitat or injured/killed through bird strike with new barriers.
  • Direct adverse impacts on spawning grounds and nursery areas (e.g. for saithe, mackerel and whiting) for fish species that will be permanently affected by the footprint of works in this area and could be adversely impacted upon by changes in sediment deposition and turbidity. It should be noted that the footprint of the works will be small in comparison to the overall area of the spawning and nursery grounds. NE1, NE2 and NE3 are close to spawning grounds and nursery areas for several BAP marine fish species.
  • Moderate to major adverse impacts on medium and high sensitivity seascapes resulting from options N1, N2, N3, N4 and N7. Other options are not located in areas with seascape units. All options apart from N1 could result in moderate visual impacts on land-based receptors on the coastline.
  • Moderate adverse impacts on the visitor experience from the Heart of the Neolithic WHS on Orkney Mainland. However, these options are unlikely to significantly affect the Outstanding Universal Value of this WHS.
  • Potential for adverse impacts on two designated wrecks, protected under the Protection of Wrecks Act 1973, within the footprint of option N7. Further consideration would be needed to ensure that these wrecks and their exclusion zones will not be affected by works associated with offshore wind development.

8.5.1 Long Term

The long term options are described in Chapter 7 and in the draft Plan. Due to the timescales involved in potentially developing long term options, these have not been assessed at this stage.

8.6 Cumulative Impacts

8.6.1 Introduction

A range of in-combination and cumulative impacts associated with the short and medium term options (see Appendices 8.2 and 8.3) have been identified and are described below.

In this context, cumulative impacts are considered to be those effects of the options in association with other types of the same development (e.g. other offshore wind developments).

In-combination effects are considered to be the effects of the options in combination with other different plans, programmes and strategies (e.g. the impacts of the options in combination with other energy activities such as tidal).

There will be a need to manage the cumulative and in-combination impacts within STW and consequently it will be important to monitor other plans, programmes, activities and strategies throughout the duration of the Plan. Any impacts of other schemes or strategies on the European nature conservation sites can be assessed through the 'in-combination' part of the HRA process.

8.6.2 Cumulative Impacts of Short Term Options

With the exception of the short term options located on the west coast of Scotland (e.g. Kintyre, Islay and Argyll Array), the short term options have the potential for cumulative impacts associated with other offshore wind developments. These offshore wind developments include other short term options, medium term options, the Round 3 Offshore Wind Zones, the Beatrice demonstrator project (Beatrice option only) and the Robin Rigg wind farm (Wigtown Bay and Solway Firth options only).

Other plans and strategies such as oil and gas development, increased vessel activity in STW (e.g. associated with other new development), new developments on the coast (e.g. harbour development) or offshore (e.g. aggregate extraction areas) also have the potential to have in-combination impacts.

The cumulative impacts have been described by SEA receptor as many of the cumulative impacts are generic and are relevant to one or more of the short term options. Where cumulative or 'in-combination' effects are particularly relevant to one or more short term options in a particular locality, the locality or option is noted. Potential cumulative or in-combination impacts occurring as a result of the short term options together with other existing or future offshore wind development proposals and/or other plans and strategies include:

  • Water - the construction and decommissioning of offshore wind development at different locations in close proximity within the STW has the potential to increase sediment disturbance and elevate background turbidity levels. These changes, which remain uncertain at the strategic level (i.e. the likelihood of changes occurring and the significance of impact is currently unknown), may affect wildlife that is dependent on existing water conditions and parameters, and the ability of commercial fish species to spawn, respire and feed.
  • Geology, sediments and coastal processes - potential cumulative disturbance from offshore wind developments to the seabed (e.g. from scouring), which may affect water quality and sediment in the water column, with associated impacts on wildlife and fisheries, and on coastal geological SSSIs. These strategic impacts are likely to be localised.

The short term options lying on the east coast of Scotland (e.g. Inch Cape, Bell Rock, Neart na Gaoithe and Forth Array) are likely to have the highest potential to result in 'in-combination' adverse impacts on sediment circulation from other plans and strategies, notably harbour and waterfront developments at Edinburgh and Bo'ness, and the Firth of Forth licensed aggregate extraction area. The proposed new Forth replacement crossing and offshore sewage outfalls may also affect turbidity and together with the short term options on the east coast, may affect the morphology of subtidal beds and the shoreline.

  • Biodiversity, flora and fauna - (see Appendix 3 of the HRA Screening Report for in-combination effects on Natura 2000 sites):

o increased number of physical and disturbance barriers to fish movement/migration from offshore wind developments and other plans and strategies.

o multiple noise sources audible to marine mammals, particularly during construction, may occur at the same time and extend over a long period, adversely affecting marine mammals. Timing of construction of short term options with other developments is therefore crucial to avoid unnecessary adverse cumulative impacts.

o increased vessel disturbance to marine mammals, particularly during the construction phase.

o bird increased collision risk.

o potential for beneficial cumulative impacts of options through increased structures providing new reef habitat and new substrate and potential to act as fish aggregation devices.

Further consideration of cumulative impacts of the short term options on biodiversity is required and will be carried out as part of the HRA.

  • Landscape/seascape and visual amenity - potential for cumulative adverse effects on seascape character, as a result of options lying within high sensitivity seascapes or within 13km of nationally designated landscapes, and on visual amenity for receptors along the coastline.

The greatest potential cumulative landscape/seascape and visibility impacts are likely to occur at Solway Firth and Wigtown Bay. However the significance of the cumulative impacts will be dependent on their degree of separation, the number of wind farms progressed and their similarity in design. Both options lie within a vulnerable area i.e. a high sensitivity seascape, within 8km of a nationally designated landscape, within 8km of visual receptors on the coastline and the Robin Rigg offshore wind site borders the north eastern section of the Solway Firth. Both short term options together with the Robin Rigg site may be visible from a single point on the coastline.

Further consideration of the combined presence of existing and proposed wind farms in this southern part of Scotland will therefore require further consideration (using SNH's guidance on assessing the cumulative effects of wind farms) at project level. The combined effects of other types of developments in conjunction with wind generation proposals need to be considered at a detailed scale on a site by site basis.

Indirect impacts on recreation and tourism may also be experienced as a result of a significant change in visual amenity and landscape/seascape character.

  • Population and human health - potential combined pressures of those using the sea for recreation, i.e. increasing number of vessels being displaced from areas due to new offshore developments.

The greatest cumulative recreational pressures are likely to originate from potential offshore wind farms at Wigtown Bay and Solway Firth together with the Robin Rigg site, as the Solway Coast is considered of great importance for informal recreation (including sea angling) and visual amenity/seascape may be significantly affected. Vessel traffic may cause disturbance to or displacement of recreational users.

The greatest cumulative impacts on recreation may occur during the offshore wind construction and decommissioning phases when vessel traffic is likely to be higher.

  • Cultural heritage - potential combined pressures on setting of listed structures from various offshore wind zones/developments.

Bell Rock is likely to be the short term option most likely to result in cumulative impacts on cultural heritage requiring further consideration at project level. Construction of an offshore wind farm at Bell Rock may disturb a listed lighthouse and in-combination with Round 3 Offshore Wind Farms in the Firth of Forth, and the short term options of Inch Cape and Neart na Gaoithe, may affect the setting of this listed structure.

Further consideration of the landscape and visual impacts of any existing or future on-shore developments will require cumulative impact assessment due to the proximity of the closest part of Kintyre lying within 1km of the coastline and the high sensitivity seascape within which this option lies.

8.6.3 Cumulative Impacts of Medium Term Options

The generic cumulative and in-combination impacts described in section 8.6.2 are likely to be applicable to the medium term options.

Specific cumulative and in-combination impacts associated with particular medium term options are considered further in this section.

  • East Area - The footprint of E1 is large (2022 km2) and together with the short term options of Bell Rock, Inch Cape, Neart na Gaoithe and Forth Array would be likely to have significant cumulative impacts on biodiversity, flora and fauna and other SEA receptors, as described in section 8.6.1.

The medium term option would have a potentially adverse cumulative impact on Bell Rock listed lighthouse and its setting taking into account the short term options of Bell Rock, Neart na Gaoithe and Inch Cape, and the Round 3 Offshore Wind Farms in the Firth of Forth.

  • South West Area - All of the medium term options in this area would cumulatively provide the smallest area for offshore wind generation.

Together with the short term options (Wigtown Bay and the Solway Firth) and the Robin Rigg wind farm development, the medium term options are likely to have adverse cumulative visual amenity and landscape/seascape impacts due to their proximity to land and each other. Potentially adverse cumulative impacts on recreation in this area may also occur.

  • West Area - There are no known proposals for other offshore wind developments in this area that would have apparent in-combination effects. However, there is potential for cumulative impacts on the SEA receptors described in section 8.6.2 from developing all of the medium term options in this area, and potential for in-combination effects associated with the South of Islay Tidal Energy Project.
  • North West Area - All of the medium term options in this area would cumulatively provide the greatest area for offshore wind generation of all the regional combinations covered by the assessment, thus helping to reduce the impacts of climate change. This is considered a major beneficial cumulative impact. In addition, no short term options are considered in this area, thus limiting the cumulative impacts that may be experienced.

However, as all medium term options lie within medium to high or high sensitivity seascapes, there is potential for cumulative impacts on the already fragile landscape/seascape around the Hebridean islands.

  • North East Area - Together with the short term option of Beatrice, there is potential for the medium term options NE1 and NE2, which lie in close proximity to each other in this area, to have cumulative impacts on biodiversity receptors in and around the Moray Firth, as described in section 8.6.2.

In addition, there is potential for cumulative impacts on navigation as these options lie within an area of high shipping activity. In particular, vessel traffic associated with fisheries and important ports such as the Nigg oil terminal and Beatrice oil field, and ferry terminals at Kirkwall, Scrabster and Aberdeen, could be compounded by shipping associated with offshore wind development. This is considered further within the draft Plan.

  • North Area - There is potential for the medium term options, which lie in close proximity to each other (and some border each other) in this area, to have cumulative impacts on biodiversity receptors such as around Shetland and Orkney, as described in section 8.6.2.

The medium term options of N1, N2 and N3 could have potentially adverse cumulative impacts on Sule Skerry listed lighthouse and its setting.

8.6.4 Long Term Options

The cumulative impacts of the long term options have not been assessed at the strategic level due to the uncertainties involved in progressing the long term plan but may be considered further in the future.

8.7 Mitigation Measures

8.7.1 Overview

In accordance with Schedule 3 of the Environmental Assessment (Scotland) Act 2005, this section describes the measures proposed to manage (by preventing, reducing or offsetting) the significant adverse environmental effects described in Section 8.6. Implementation of these actions is required to ensure that the adverse environmental effects of the Plan are minimised where possible.

During the implementation of the Plan, the SEA process will continue through the following three stages to ensure that the predicted environmental effects of the Plan are managed:

  • implementation of proposed mitigation measures (identified at a high level within this chapter and to be detailed at the subsequent project level);
  • monitoring and evaluation of the environmental performance (i.e. principally the predicted effects) of the Plan (see Chapter 9); and
  • revision of the Plan during its review cycle (in 2 years time) to address any adverse effects identified during the proposed monitoring and evaluation activities.

These processes are likely to take place over a number of years and to involve periodic updates of the SEA and the Plan to ensure that significant adverse effects are mitigated in the most effective and efficient way. This will require the involvement of a range of key stakeholders in order to take their views into account and allow for transparent procedures.

The mitigation measures identified within this chapter are intended to provide a framework for further action, at either a strategic or a project level, during the Plan implementation. Actions recommended at a strategic level include the need for further assessment of the overall Plan itself and the need for extensive consultation with stakeholders during both the scheme development and subsequent Environmental Impact Assessment stages.

Specific measures to mitigate the adverse effects identified for each option and receptor have not been identified for this SEA, as these will be identified at the project level when the appropriate level of detailed information is available. Instead, the mitigation measures are identified within three over-arching categories:

  • A need for further assessment work where the information available to predict the likely effects of an option is uncertain - including strategic and site-specific studies/investigations recommended in Chapter 9;
  • Recommendations to avoid impacts on sensitive environmental receptors (e.g. World Heritage Sites, shipping routes) through the positioning of the development within the identified option boundary;
  • A need to reduce the identified impacts through the design development process and the proposed construction (including installation and decommissioning) and operational methods. Specific measures for each environmental receptor will be identified at the project level.

Under each category, specific targeted mitigation measures must be developed on a case by case basis for individual projects to ensure that the specific effects on sensitive environmental receptors are addressed.

The mitigation measures recommended for the identified significant adverse environmental effects are set out in detail for each option and environmental receptor in Appendices 8.2 and 8.3. Measures are recommended only where significant adverse effects have been predicted. Therefore, measures are recommended for all options and environmental receptors except climatic factors, as no significant strategic negative effects associated with offshore wind development in STW have been identified on climate. Instead, the Plan is likely to significantly contribute to achieving a greater proportion of renewable energy with respect to mitigating Scotland's contribution to climate change.

8.7.2 Strategic mitigation measures

The following strategic mitigation measures have been identified, in addition to the project-level mitigation recommended in Section 8.7.3, to ensure that the adverse effects of the draft Plan are avoided or minimised. These are as follows:

  • there may be a requirement to remove further options from the Plan on the basis of the findings of a strategic level Habitats Regulations Appraisal ( HRA). This would assess the likely significant effects of the draft Plan on internationally protected sites ( SPAs, SACs and Ramsar Sites). It may be necessary to change the draft Plan where adverse effects on European nature conservation sites are identified in this process, and other forms of mitigation are considered insufficient to avoid such effects arising;
  • continue communications (consultation and participation) with the SEA consultation authorities ( SEPA, SNH and Historic Scotland), regulators, key organisations (e.g. Scottish Fishermen's Federation), developers (including those that have been awarded exclusivity leases for areas inside STW), Offshore Wind Industry Group and the public to seek appropriate site-specific mitigation. Developers must be engaged in the process as early as possible together with the shipping and commercial fishing industries to develop appropriate mitigation;
  • consider the potential requirement to identify and provide habitat to help offset non-designated/nationally designated habitat losses resulting from offshore wind farm development;
  • consider the implementation and scheduling of components of offshore wind projects within STW (in combination with other planned offshore developments) to minimise strategic adverse impacts on species (e.g. migratory fish, marine mammals etc, habitats and landscape), including consideration of the cumulative and in-combination effects with other identified schemes, projects or activities;
  • undertake the further work recommended at the strategic level as described in Chapter 9.

8.7.3 Specific project-level mitigation

In general terms, the following mitigation measures are recommended (based on the three categories of measures described in Section 8.7.1) to address the predicted significant effects on environmental receptors. Details of the measures recommended for each option are provided in Appendices 8.2 and 8.3. Specific measures would be developed at the project-level.

(a) Water

  • Further assessment work is required for all options to reduce uncertainty regarding potential impacts on water quality (including Shellfish Waters). This includes a recommendation for hydrodynamic and water quality modelling at project level (see Table 9-1).
  • Specific impacts during construction, operation and decommissioning should be reduced through the selection and use of appropriate methods to reduce pollution risks, e.g. through the use of best practice marine construction procedures for prevention and control of spillages and discharges of harmful substances (such as antifouling agents, sacrificial anodes, biocides, grouts etc) to the marine environment; for sediment mobilisation and associated turbidity and secondary impacts to avoid unacceptable impacts on marine and benthic fauna.

(b) Geology, sediments and coastal processes

  • Further assessment work is required for all options to reduce uncertainty regarding potential impacts on coastal processes. This includes a recommendation for sediment dynamic modelling at project level (see Table 9-1).
  • Optimise the location and arrangement of structures and their arrangement during the design process to mitigate any issues of erosion or deposition and resulting impacts on sensitive receptors.

(c) Biodiversity, flora and fauna

  • Key areas for species and habitats of nature conservation (e.g. legally designated sites, Important Bird Areas, flight corridors and migratory routes) and fisheries value (e.g. spawning grounds) should be avoided, where known, through the positioning and subsequent design of the development.
  • Specific impacts on species and habitats (including fisheries) should be reduced through appropriate design (e.g. minimising footprint of the development to minimise loss or damage to seabed habitat), and selection and use of appropriate construction (e.g. timing to avoid key seasons; selection of low noise and minimal vibration installation technologies; utilisation of 'soft start' practices for plant and vessels to minimise disturbance and allow mobile species to move away from areas of disturbance) and operation methods (e.g. use of noise attenuation technologies);
  • Further work is required at a strategic and project level to determine impacts on international nature conservation sites - to be assessed through the HRA process.

(d) Landscape and seascape

  • Where wind farms are visible from the coastline or in high sensitivity seascapes, specific impacts on visual receptors (from the coast or at sea) should be avoided, if possible, or reduced through appropriate design (e.g. minimising footprint of the construction and decommissioning works; reducing turbine heights where feasible) and positioning of development within the option boundary.
  • Developments within the vicinity of NSAs and AONBs should be avoided through appropriate positioning within the option boundary.

(e) Population and human health

  • Developments should avoid RYA cruising routes and areas of known high recreational activity/importance where possible through appropriate positioning within the option boundary.
  • Specific impacts should be reduced through appropriate design and selection and use of appropriate construction and operation methods.

(f) Cultural heritage

  • Developments should avoid WHS, listed buildings (and their settings) and wrecks (both designated and non-designated) where possible through appropriate positioning within the option boundary, and where impacts cannot be avoided, these should be reduced through appropriate design.

(g) Material assets

  • Developments should avoid shipping routes, other renewable energy developments (e.g. wind, wave), etc, where possible through appropriate positioning within the option boundary. Where impacts cannot be avoided, these should be reduced through appropriate design.

8.8 Residual effects

The potential effectiveness of the mitigation measures recommended in Section 8.7 have been considered to determine, at a high level, the potential residual environmental effects of the short and medium term options.

Where further work has been recommended because the potentially significant effects remain uncertain; the residual effect remains uncertain and there is no change from the conclusions of the assessment undertaken prior to mitigation. This is the case for all options where the likelihood of significant impacts on water quality (including that in Shellfish Waters) and coastal processes remain uncertain.

In addition, due to considerable uncertainty regarding the potential effects on biodiversity, flora and fauna, in particular pending the outcome of the HRA process and further assessment work; the significance of the residual effect (identified as moderate/major prior to mitigation) has been identified as uncertain for all options.

For all predicted significant effects, it has been assumed that the recommended mitigation to avoid or reduce impacts (details of which would be developed at the project level) described in Section 8.7 would reduce the significance from major/moderate to minor where legal requirements/Government policy would ensure that impacts would be avoided (e.g. there would be restrictions on development that would pose an unacceptable risk to navigational safety); and to moderate (in the case of landscape) where the mitigation opportunities are more limited (e.g. where it may not be possible to site a development in a location that could effectively avoid a sensitive receptor).

On this basis, the recommended mitigation has reduced the significance of the effects on environmental receptors for the majority of the short and medium term options. A summary of the predicted residual environmental effects following mitigation of all options is presented in Table 8-4.

It should be noted that the identification of additional environmental sensitivities following consultation, additional work and the maintenance review of the SEA may increase or decrease the severity of the identified residual impacts.

Table 8.4. Residual effects

Site

Area (km2)

Climatic Factors

Water

Geology Sediments & Coastal Processes

Biodiversity, Flora & Fauna

Landscape & Visual Amenity

Population & Human Health

Cultural Heritage

Material Assets

Absence of Plan

Moderate to Major NegativeNeutralNeutralNeutralNeutralNeutralNeutralNeutral

Short Term Option

Beatrice

121

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

Inch Cape

150

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

Bell Rock

93

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeMinor NegativeMinor Negative

Neart na Gaoithe

105

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

Forth Array

128

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

Solway Firth

61

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

Wigtown Bay

51

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

Kintyre

69

Moderate to Major PositiveUncertainUncertainUncertainModerate to Major NegativeMinor NegativeNeutralMinor Negative

Islay

95

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

Argyll Array

361

Moderate to Major PositiveUncertainUncertainUncertainModerate to Major NegativeMinor NegativeMinor NegativeMinor Negative

Medium Term Option

W1

1491

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

W2

1039

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeUncertainMinor Negative

W3

57

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

W4

253

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

SW1

7

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

SW2

93

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

SW3

354

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

SW4

24

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

SW5

55

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

SW6

16

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

N1

1671

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeMinor NegativeMinor Negative

N2

449

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeMinor NegativeMinor Negative

N3

1535

Moderate to Major PositiveUncertainUncertainUncertainModerate to Major NegativeMinor NegativeModerate to Major NegativeMinor Negative

N4

776

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

N5

1079

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

N6

222

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

N7

1729

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeMinor NegativeMinor Negative

N8

300

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

E1

2022

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeMinor NegativeMinor Negative

NW1

206

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeModerate to Major NegativeMinor Negative

NW2

1278

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

NW3

277

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeModerate to Major NegativeMinor Negative

NW4

156

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

NW5

324

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

NW6

914

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

NW7

2554

Moderate to Major PositiveUncertainUncertainUncertainModerate change (Landscape and visual)Minor NegativeNeutralMinor Negative

NW8

2531

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

NE1

387

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeUncertainMinor Negative

NE2

170

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

NE3

131

Moderate to Major PositiveUncertainUncertainUncertainMinor NegativeMinor NegativeNeutralMinor Negative

Key

Symbol

Impact Significance

Moderate to Major Positive

Moderate to Major Positive

Minor Positive

Minor Positive

Neutral

Neutral

Uncertain

Uncertain

Minor Negative

Minor Negative

Moderate to Major Negative

Moderate to Major Negative

Symbol

Impact Significance

Moderate change (Landscape and visual)

Moderate change (relates to landscape and visual amenity only)