Pentland Firth and Orkney Waters Enabling Actions Report: Ornithological Cumulative Impact Assessment Framework


Title: Pentland Firth and Orkney Waters Enabling Actions Report: Ornithological Cumulative Impact Assessment Framework
Publication Date:
May 30, 2013
Pages: 207
Sponsoring Organization:

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MacArthur, D.; Furness, B.; Trinder, M.; MacArthur, K. (2013). Pentland Firth and Orkney Waters Enabling Actions Report: Ornithological Cumulative Impact Assessment Framework. Report by MacArthur Green. pp 207.

MacArthur Green has been commissioned by The Crown Estate to produce a methodological framework for the assessment of ornithological cumulative and in combination impacts of the Pentland Firth and Orkney Waters (PFOW) wave and tidal projects. This work is part of The Crown Estate’s Enabling Actions work to accelerate and de-risk the development of the PFOW wave and tidal projects.


This report details the Ornithological CIA Framework and is supported by the following three appendices:

  • Appendix 1: Ornithological Cumulative Impact Assessment Framework. Pentland Firth and Orkney Waters Wave and Tidal Projects; Supporting Information. This report contains all associated appendices and the Strategic Review completed as part of this project.
  • Appendix 2: Ornithological Cumulative Impact Assessment Framework. Pentland Firth and Orkney Waters Wave and Tidal Projects; Worked Example Scoping Report. This report provides a scoping report for a hypothetical wave site.
  • Appendix 3: Ornithological Cumulative Impact Assessment Framework. Pentland Firth and Orkney Waters Wave and Tidal Projects; Worked Example. This report provides a worked example of an Ornithological CIA for a hypothetical wave site.


The conclusion of the Strategic Review included in Appendix 1 is that wave and tidal current developments will have a relatively low impact on PFOW seabird populations, particularly in comparison to other factors affecting seabird populations.


This guidance has been developed through detailed consultation with the Project Steering Group and wider consultation with various organisations through a workshop held on 11 October 2012. The Project Steering Group comprised representatives from The Crown Estate, from the regulators and their advisors (Marine Scotland Science, Marine Scotland Licencing and Scottish Natural Heritage) and the renewables industry (Niras Consulting [as adviser to The Crown Estate for this project], ScottishPower Renewables, Aquamarine Power and SSE Renewables). MacArthur Green and The Crown Estate wish to thank the Project Steering Group and the various attendees of the workshop who have contributed valuable input to the development of this guidance. We also wish to thank JNCC for their helpful advice and previews of reports in preparation.


Marine Scotland and SNH, as part of the Project Steering Group, have reviewed the documents and have indicated their broad support of the approach adopted in the framework and worked example.


The Environmental Impact Assessment (EIA) Regulations and Habitats Regulations both require the full consideration of cumulative impacts. Although the Habitats Regulations refer to ‘in combination’ impacts instead of cumulative impacts, this report refers to these as ‘Ornithological Cumulative Impact Assessment’ (Ornithological CIA).


Ornithological CIA has proven to be challenging. In the context of Ornithological CIA for offshore wind farm developments, King et al. (2009) found that the approach lacked a systematic, standardised method and data. The approach was often qualitative rather than quantitative. This created uncertainty over conclusions, and ultimately caused delays in the consenting process. Causes of these issues were:

  1. Inadequate scoping;
  2. Lack of understanding of which species/populations were involved;
  3. Lack of understanding of which projects should be included;
  4. Lack of systematic assessment methodology;
  5. Tendency for CIA to be left to the end of the consenting process as an ‘add-on’ rather than being approached in the same strategic way as EIA.


The reason that this Ornithological CIA method has been prepared is to provide guidance to avoid similar issues arising for wave and tidal developments in the PFOW. This will help developers to submit comprehensive and proportional Ornithological CIA as part of their Environmental Statement (ES) , and will ultimately help to speed up the consenting process by ensuring regulators and their advisors receive sufficient information on which to make consenting decisions in a timely fashion.


The invitation to tender from The Crown Estate detailed the aim of this Project:

‘The aim of the Project is to produce a methodological framework to help guide, in an agreed and consistent manner and in the potential absence of information on other projects and/or species abundance, PFOW developer Cumulative Impact Assessments (CIA) in the identification and analysis of ornithological cumulative and in-combination impacts at the project level.’


The aim is achieved by the following objectives:


(Objective 1) Define the Ornithological CIA Framework and detail clearly the stages involved within it.

(Objective 2) For each relevant stage of the Ornithological CIA Framework, provide guidance on the recommended approach and methods to address areas of uncertainty.

(Objective 3) Make recommendations as to the need for, and benefits of, further strategic work regarding Ornithological CIA and the consenting of wave and tidal projects in the PFOW.

(Objective 4) Complete a high level strategic review of the factors influencing the dynamics of seabird populations, putting potential cumulative impacts of wave and tidal current projects into the wider context of changing background numbers of seabirds (Appendix 1, Section 5).


The following Ornithological CIA Framework and associated stages are identified under Objective 2 and recommendations provided for each of these stages where relevant.


Stage Description

  1. Scoping
  2. Define the Target Bird Populations and designated sites to include in the Ornithological CIA
  3. Defining the plans and projects to include in the Ornithological CIA
  4. Identifying relevant Cumulative Impacts to consider in the Ornithological CIA
  5. Define Vulnerability of Target Bird Populations to development
  6. Establish Conservation Status of Target Bird Populations and their respective baselines for the assessment
  7. Detail relevant data collection methods
  8. Data acquisition from other developments
  9. Detail relevant data analysis methods, compatibility and presentation
  10. Determine the significance of Cumulative Impacts
  11. Mitigation Measures
  12. Residual Effects


Ornithological CIA should be fully integrated into the EIA and Habitats Regulations Appraisal (HRA) processes. It is important to emphasise here that it should not be seen as a separate process; the intention of the EIA Regulations and the Habitats Regulations is that cumulative / in combination impacts are an integral part of the assessment and should therefore be considered from the very beginning of the assessment process. It is essential therefore that the Ornithological CIA should be clearly integrated into these established processes and related methodologies. The intention is that this Framework serves to help with this and serves to create a more consistent, proportionate and certain process for all.


Recommendations are given for further strategic work for Ornithological CIA under Objective 3. It is recommended that it would be beneficial to undertake further strategic work on the following issues:

  • Identifying Target Bird Populations and projects relevant to each PFOW wave and tidal project;
  • Data acquisition;
  • Assessment of existing data that could inform on impacts on seabirds;
  • Determination of thresholds for acceptable population change; and,
  • Updated data on SPA populations.


A strategic review is completed under Objective 4 as noted above (Framework Section 6). This review concludes that wave and tidal current energy developments will have a relatively low impact on PFOW seabird populations when compared with other impacts. These include food abundance, fisheries, mammal predation and climate change. Against this backdrop of large scale effects on seabird populations, any impacts from wave and tidal current energy pro jects may be too low to detect, even when considering changes to the most vulnerable seabird populations. In light of this conclusion, it is our view that Ornithological CIA for wave and tidal current energy developments and statutory authorities should take into consideration the relatively minor nature of the predicted ornithological impacts.


Finally, it is important to note that information on bird sensitivities, population vulnerability, population sizes and conservation status will continue to be updated, and information presented in this report will need to be revised regularly to take account of new information, rather than being considered a static resource. Post-construction monitoring at developed sites will play an important role in refining our understanding of the potential (cumulative) impacts and also, therefore, this guidance.


The Ornithological CIA Framework and supporting information has been developed through a workshop and detailed engagement with key stakeholders. However, it is important to stress that it is not statutory guidance and is not intended to detail a specific process/approach which developers are required to follow.


Developers will of course take their own approach to ornithological CIA, and that approach will no doubt need to reflect relevant issues on a site-specific basis. The aim of the framework and supporting information is to assist those involved in consenting and ornithological CIA and promote a more consistent, proportional and practical approach to ornithological CIA.

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