20.1. Introduction

20.1.1.              Overview

  1. This chapter of the Offshore Environmental Impact Assessment (EIA) Report presents the assessment of the likely significant effects (as per the “EIA Regulations”) on the environment of the Berwick Bank Wind Farm offshore infrastructure which is the subject of this application (hereafter referred to as “the Proposed Development”) in relation to inter-related effects. Specifically, this chapter considers the potential impacts of the Proposed Development seaward of Mean High Water Springs (MHWS) during the construction, operation and maintenance, and decommissioning phases.
  2. Likely significant effect is a term used in both the “EIA Regulations” and the Habitat Regulations. Reference to likely significant effect in this Offshore EIA Report refers to “likely significant effect” as used by the “EIA Regulations”. This Offshore EIA Report is accompanied by a Report to Inform Appropriate Assessment (RIAA) which uses the term as defined by the Habitats Regulations Appraisal (HRA) Regulations.
  3. The assessments presented within this chapter have drawn upon individual chapters relevant assessment of effects and conclusions and their associated appendices in this Offshore EIA Report including:
  • volume 2, chapter 7: Physical Processes;
  • volume 2, chapter 8: Benthic Subtidal and Intertidal Ecology;
  • volume 2, chapter 9: Fish and Shellfish Ecology;
  • volume 2, chapter 10: Marine Mammals;
  • volume 2, chapter 11: Offshore and Intertidal Ornithology;
  • volume 2, chapter 12: Commercial Fisheries;
  • volume 2, chapter 13: Shipping and Navigation;
  • volume 2, chapter 14: Aviation, Military and Communications;
  • volume 2, chapter 15: Seascape, Landscape, Visual Resources;
  • volume 2, chapter 16: Cultural Heritage;
  • volume 2, chapter 17: Infrastructure and Other Users;
  • volume 2, chapter 18: Offshore Socio-Economics and Tourism; and
  • volume 2, chapter 19: Water Quality.
    1. This chapter is split into two parts. The first part contains a receptor based inter-related effects assessment (section 20.6), and the second part provides an ecosystem effects assessment (20.7). In addition to volume 2, chapters 7 to 19 listed above, the Ecosystem Effects Assessment draws upon volume 3, appendix 20.1.

20.1.2.              Purpose of this Chapter

  1. The primary purpose of the Offshore EIA Report is outlined in volume 1, chapter 1. It is intended that the Offshore EIA Report will provide the Scottish Ministers, statutory and non-statutory stakeholders with sufficient information to determine the LSEs of the Proposed Development on the receiving environment.
  2. In particular, this Offshore EIA Report chapter presents:
  • the receptor groups considered within the inter-related effects assessment;
  • the potential for effects on receptor groups across the three key project phases (construction, operation and maintenance and decommissioning);
  • the potential for multiple effects on a receptor group, as presented within the topic specific chapter, to interact to create inter-related effects; and
  • the inter-related effects across different trophic levels of the ecosystem, from prey species to predators.
    1. This chapter follows the ecosystem based approach, which is defined as “a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way” (SCBD, 2012). The purpose of the ecosystem based approach is to assess how the LSEs associated with the Proposed Development may interact through the ecosystem, affecting the environment.

20.1.3.              Study Area

  1. Due to the differing spatial extent of effects experienced by different offshore receptors, the study area for potential inter-related effects varies according to topic and receptor. The potential inter-related effects considered in this chapter are, therefore, also limited to the study areas defined in each of the topic specific chapters outlined in paragraph 3.
  2. As the largest study area relates to offshore ornithology, this is the maximum limit of the inter-related effects study area.
  3. As part of the consultation process, some topic chapters from those included in paragraph 3 have been excluded from further inter-related effects assessment. The rationale for this exclusion is presented in section 20.3 (see Table 20.1   Open ▸ ).

20.2. Policy and Legislative Context

  1. The policy and legislative context for the Proposed Development is set out in volume 1, chapter 2 of the Offshore EIA Report.
  2. Of particular relevance, Article 3(1) of the EIA Directive requires that the interaction between the environmental (e.g. human health, biodiversity, land, soil, water, air and climate etc) is identified, described and assessed in an EIA report.
  3. Under the EIA Regulations, there is a requirement to consider inter-relationships between topics that may lead to environmental effects. Other than this, there is no policy relevant to inter-related effects in Scotland, thus this chapter has been compiled following advice from stakeholders as detailed in section 20.3 ( Table 20.1   Open ▸ ).

20.3. Consultation

  1. A summary of the key issues raised during consultation activities undertaken to date specific to inter-related effects is presented in Table 20.1   Open ▸ . Topic chapters which are relevant to the ecosystem based approach include physical processes, benthic ecology, fish and shellfish, marine mammals and offshore ornithology.
  2. For each of these topics a Road Map process has been used as a tool to facilitate early and on-going engagement with stakeholders throughout the pre-application phase of the Proposed Development including on reaching points of agreement on scoping impacts out of the assessment, and/or agreeing the level of assessment which will be presented for impacts, so that the focus of the Offshore EIA Report is on likely significant environmental effects as defined by the EIA Regulations. The Road Map for these topics (up to date at the point of Application) are presented in volume 3 as follows:
  • volume 3, appendix 8.2: Benthic Ecology, Fish and Shellfish Ecology and Physical Processes Road Map;
  • volume 3, appendix 10.3: Marine Mammal Road Map; and
  • volume 3, appendix 11.8: Offshore Ornithology Road Map.
    1. At the request of Marine Scotland Licensing Operations Team (MS-LOT)[1], an audit document (Audit Document for Post-Scoping Discussions (volume 3, appendix 5.1)) has been produced and submitted alongside the application to document discussions on key issues, post-receipt of the Berwick Bank Wind Farm Scoping Opinion (MS-LOT, 2022).

Table 20.1:
Summary of Key Issues Raised During Consultation Activities Undertaken for the Proposed Development Relevant to Inter-Related Effects

Table 20.1: Summary of Key Issues Raised During Consultation Activities Undertaken for the Proposed Development Relevant to Inter-Related Effects

20.4. Data Sources

  1. The baseline environments for the receptor groups considered in section 20.6 of this chapter are specific to each receptor group and are, therefore, set out in detail in the relevant topic specific chapters. For the purposes of the ecosystem effects assessment in section 20.7, a summary of the baseline informed by volume 2, chapters 7 to 11 and their respective technical reports is described to provide an overview of the ecosystem baseline conditions.
  2. This chapter draws on the conclusions made within the technical chapters for the assessment of impacts acting in isolation on the receptor groups. The relevant sections drawn upon in this interrelated effects assessment are presented in the Offshore EIA Report in volume 2 chapters 7 to 19.

20.5. Assessment Methodology

  1. The assessment presented in this chapter has been split into two parts, Part One: Receptor Based Inter-Related Effects Assessment and Part Two: Ecosystem Effects Assessment.

20.5.1.              Part One: Inter-Related Effects Assessment Method

  1. The following sections present the approach for the inter-related effects assessment for the Proposed Development. For the purpose of this assessment, the following definition of inter-related effects has been applied throughout this chapter:
  2. Multiple effects upon the same receptor arising from the Proposed Development occur either where a single effect acts upon a receptor over time to produce a potential additive effect or where a number of separate effects, such as underwater noise and habitat loss, affect a single receptor, for example marine mammals.
  3. Two types of inter-related effects have therefore been identified:
  • project lifetime effects - individual effects on each of the key receptor groups across the three Proposed Development phases (construction, operation and maintenance, and decommissioning); and
  • receptor-led effects - multiple effects on the same receptor.
    1. Table 20.2   Open ▸ presents a full definition of the above terms.


Table 20.2:
Definitions of Proposed Development Lifetime Inter-Related Effects and Receptor-led Inter-Related Effects

Table 20.2: Definitions of Proposed Development Lifetime Inter-Related Effects and Receptor-led Inter-Related Effects



  1. There is limited guidance available relating to assessment of inter-related effects however the following guidance documents have been followed:
  • The Guidelines for the Assessment of Indirect and Cumulative Impacts as well as Impact Interactions (EC, 1999); and
  • Institute of Environmental Management and Assessment (IEMA) Environmental Impact Assessment Guide to Shaping Quality Development (IEMA, 2016).

Approach to assessment

  1. The approach to assessing inter-related effects within Part One of this chapter has followed a four stage process, as summarised in Table 20.3   Open ▸ and outlined below. More details of the approach summarised above and used to develop this chapter are presented in volume 1, chapter 6.


Table 20.3:
Staged Approach to Assessing Inter-Related Effects

Table 20.3: Staged Approach to Assessing Inter-Related Effects


Stage 1: Topic specific assessments
  1. The first stage of the assessment of inter-related effects is presented in each of the individual Offshore EIA topic chapters and comprises the individual assessments of effects on receptors across the construction, operation and maintenance and decommissioning of the Proposed Development.
Stage 2: Identification of receptor group
  1. Stage 2 involved a review of the assessments undertaken in the topic specific chapters to identify ‘receptor groups’ requiring assessment within the inter-related effects assessment. The term ‘receptor group’ is used to highlight that the approach taken for the inter-related effects assessment will not assess every individual receptor assessed at the EIA stage, but rather potentially sensitive groups of receptors. The receptor groups assessed can be broadly categorised as those relating to the physical environment, the biological environment and the human environment, as follows:
  • physical environment:

-        physical processes; and

-        water quality.

  • biological environment:

-        benthic subtidal and intertidal ecology;

-        fish and shellfish ecology;

-        marine mammals; and

-        offshore and intertidal ornithology.

  • human environment:

-        commercial fisheries;

-        shipping and navigation;

-        aviation, military and communication;

-        seascape and visual resources;

-        cultural heritage;

-        infrastructure and other users; and

-        offshore socio-economics and tourism.

Stage 3: Identification of potential interactions on receptor groups
  1. Following the identification of receptor groups, the potential inter-related effects on these receptor groups have been identified via review of the assessment of effects sections for each topic chapter. The judgement as to which impacts may result in inter-related effects upon receptors associated with the Proposed Development was exercised using a precautionary approach and was based on the professional judgement and experience of the technical author.
Linked receptor groups
  1. It is important to recognise potential linkages between the topic-specific chapters, whereby effects assessed in each chapter have the potential for secondary effects on any number of other receptors. Examples include:
  • volume 2, chapter 8 addresses effects on benthic habitats and species arising from changes to the physical environment (as described in volume 2, chapter 7);
  • volume 2, chapters 10 and 11 assess the effects on marine mammal and seabird receptors arising from potential changes in the distribution of fish, which form their principal prey (as described in volume 2, chapter 9);
  • volume 2, chapter 12 assesses the effects on commercial fisheries receptors arising from potential impacts on commercial species of fish and shellfish as a result of a combination of effects caused by Electromagnetic Fields (EMFs), suspended sediments, habitat alteration/loss and underwater noise impacts; and
  • volume 2, chapter 17 assesses the effects on aggregate extraction areas arising from potential impacts on aggregate resource as a result of potential increase in suspended sediment concentrations (SSC) and deposition and effects on sediment transport pathways (as described in volume 2, chapter 7).
    1. Where such linked relationships arise these have been fully assessed within the individual topic chapters. This chapter on inter-related effects therefore summarises the consideration of these inter-related effects on linked receptors already set out in the topic specific chapters.
    2. It should be noted that it is not considered that there are likely to be any cumulative receptor led effects from onshore and offshore activities associated with the Project. This is primarily due to offshore export cable installation using trenchless techniques (such as Horizontal Directional Drilling (HDD)) through the intertidal area between Mean Low Water Springs (MLWS) and MHWS. As a result this has not been considered further in this Inter-Related Effects Offshore EIA Report chapter or the inter-related effects chapter of the Onshore EIA Report (volume 4, chapter 15.2) (SSER, 2022a).
Stage 4: Assessment of interactions on each receptor group
  1. Individual effects on each of the key receptor groups have been identified across the three Proposed Development phases (i.e. Proposed Development lifetime effects) as well as the interaction of multiple effects on a receptor (i.e. receptor-led effects), as defined in Table 20.2   Open ▸ . The assessment of these interactions has been presented in this chapter using a matrix approach, (see Table 20.4   Open ▸ to Table 20.15   Open ▸ ).
  2. It is important to note that the interactions assessment in Part One considers only those effects produced by the Proposed Development and not those effects arising from other projects, which are considered within the Cumulative Effects Assessment (CEA) sections of each topic chapter. However, cumulative effects between projects have been considered in Part Two: Ecosystem Effects Assessment.
  3. Within the interactions matrix for each topic, the significance of the individual effects, as concluded within the topic specific chapters, have been presented for each receptor group. A descriptive assessment of the scope for these individual effects to interact to create a different or greater effect has then been undertaken and presented (see Table 20.4   Open ▸ to Table 20.15   Open ▸ ). This assessment incorporates qualitative and, where reasonably possible, quantitative assessments. The assignment of significance of effect to any such interactive effect is not undertaken, rather, any interactive effects that may be of greater significance than the individual effects acting in isolation on a given receptor are identified and discussed within this chapter.
  4. The interactions assessment presents and utilises the maximum significant adverse effects for the Proposed Development (i.e. the maximum design scenarios including implementation of any further mitigation where appropriate), noting that individual effects may not be significant at the topic-specific level but could become significant when their interactive effect is assessed. Effects of negligible significance or greater (slight, moderate, major or profound) may occur in only one phase of the project lifecycle (e.g. during the construction phase, but not during the operation and maintenance or decommissioning phases). Where this is the case, it has been made clear that, as a result, there will be no interactive effects across the project phases. Effects of imperceptible significance identified in the individual topic assessments have been included, since there is the potential for interactive effects to increase the level (significance) of effect when considered with other sources.

20.5.2.              Part Two: Ecosystem Based Effects Assessment Method

  1. The purpose of the ecosystem-based assessment is to qualitatively assess the potential impacts of the Proposed Development at the ecosystem level, to better understand how predator – prey relationships could be altered and how this could impact the functioning of the ecosystem.
  2. The method applied to undertake this assessment has been led by the questions NatureScot raised in the ornithology Road Map Meeting 5, January 2022 ( Table 20.1   Open ▸ ). It should be noted, however, that it was agreed during the Ornithology Road Map Meeting 5, that an ecosystem modelling approach or ecosystem services approach were not deemed appropriate for this assessment. Part Two has therefore been broadly structured around these questions: “What are the predators? What are the prey species? How does the whole food chain operate? What other pressures are on these prey species? For example, certain fish prey on other fish species - what are all the impacts on prey species before an Offshore Wind Farm is built? What effect will an Offshore Wind Farm have on these prey species, in relation to these other impacts? What are the knock-on effects on predators? If prey species increase following construction of an Offshore Wind Farm, where are they? Does this new distribution draw more predators in? (volume 3, appendix 11.8, annex A).”
  3. The structure of Part Two is as follows:
  • section 20.7: Part Two: Ecosystem Effects Assessment;
  • section 20.7.1: Overview;
  • section 20.7.2: Ecosystem baseline;
  • section 20.7.3: The Marine Food Web;
  • section 20.7.4: The Key Predator Species;
  • section 20.7.5: The Key Prey Species;
  • section 20.7.6: How the Whole Ecosystem Works;
  • section 20.7.7: Future Ecosystem Baseline;
  • section 20.7.8: Existing Pressures on Prey Species;
  • section 20.7.9: Effects of the Proposed Development on Prey Species; and
  • section 20.7.10: Effects of the Proposed Development on Predators.
    1. Information and conclusions from the relevant chapters of the Offshore EIA Report and their corresponding technical reports, along with volume 3, appendix 20.1 and the Firth of Forth Banks Complex (FFBC) MPA Report, have been used to build up a picture of the marine ecosystem in the locality of the Proposed Development. This information has also been used to inform the assessments within these sections to ultimately conclude whether the Proposed Development, and cumulatively with other plans and projects, has the potential to result in changes to prey species which in turn will result in changes to predator species.
    2. Currently our understanding of how offshore wind farms impact marine food webs is limited.
    3. The Ecological Consequences of Offshore Wind research programme (ECOWind) will investigate all possible effects of offshore wind farms on the marine environment. The outcomes of this research will be used to inform policy measures to minimise negative impacts on marine life while tackling climate change and will be key to informing ecosystem assessment approach.
    4. The Aberdeen and Grampian Chamber of Commerce (2022) commented that “Preliminary studies indicate that windfarms may influence the food production at the base of the marine food chain and our range of real data collection and modelling approaches will take this new understanding from physics to fish, to ecosystems to help ensure we make the most efficient use of our marine spaces.” (Aberdeen & Grampian Chamber of Commerce, 2022)).