Decommissioning phase

Magnitude of impact

  1. The magnitude of any residual infrastructure which cannot be removed leading to changes in the hydrodynamic environment and sediment transport during the decommissioning phase, has been assessed as negligible for the Proposed Development alone, in section 7.11.
  2. The offshore wind farm developments considered within the operation and maintenance phase of the Proposed Development have a similar lifespan and would therefore also be in the decommissioning phase with residual infrastructure remaining (such as only those scour and cable protection structures not possible or practical to be removed). Decommissioning activity from the multiple developments would have a negligible magnitude of impact on tidal currents, wave climate and sediment transport, the effects of which would not overlap with other developments as documented in the Neart na Gaoithe EIA Report (Mainstream Renewable Power Ltd, 2012).
  3. The cumulative impact is predicted to be of local spatial extent, long term duration, and highly reversibility. It is predicted that the impact will affect the receptor Firth of Forth Banks Complex ncMPA directly with a low magnitude and other receptors within the Firth of Forth SSSI, Berwickshire and North Northumberland Coast SAC, Berwickshire Coast SSSI, Pease Bay SSSI, St Abb's Head to Fast Castle SSSI and Barns Ness SSSI indirectly with negligible magnitude.

Sensitivity of the receptor

  1. The cumulative effects of the decommissioning of the wind farm infrastructure from multiple offshore wind farm developments in situ does not further impact the Firth of Forth Banks Complex ncMPA or other receptors, more than a single development due to the impacts of decommissioning typically reserved to the vicinity of the developments.

Significance of the effect

  1. The cumulative effect will therefore be of negligible adverse significance for the Firth of Forth Banks Complex ncMPA receptors and of negligible adverse significance for the coastal receptors, which is not significant in EIA terms.

Further mitigation and residual effect

  1. No physical processes mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section Table 7.14   Open ▸ ) is not significant in EIA terms.

Tier 3

Construction phase

Magnitude of impact

  1. The Eyemouth Pontoon is a floating structure sited within Gunsgreen Basin purposed to support the Neart na Gaoithe Offshore Wind Farm and would therefore be decommissioned when no longer in use. Although the development lies within the physical processes CEA study area, due to the diminutive scale and location, no impacts were predicted from the installation, operation and decommissioning of the pontoon to the assessed receptors.

Sensitivity of the receptor

  1. The Eyemouth Pontoon would not contribute to impacts on receptors therefore the cumulative effect will therefore be of negligible to minor significance for the Firth of Forth Banks Complex ncMPA receptors and negligible for the Firth of Forth SSSI, Berwickshire and North Northumberland Coast SAC, Berwickshire Coast SSSI, Pease Bay SSSI, St Abb's Head to Fast Castle SSSI and Barns Ness SSSI coastal receptors.

Significance of the effect

  1. Due to the negligible adverse significance of the Eyemouth Pontoon on the Firth of Forth Banks Complex ncMPA receptors and the negligible adverse significance for the coastal receptors, the is not significant in EIA terms.

Further mitigation and residual effect

  1. No physical processes mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section Table 7.14   Open ▸ ) is not significant in EIA terms.
Operation and maintenance phase

Magnitude of impact

  1. As with the construction phase, the Eyemouth Pontoon has no impact on the assessed receptors.

 

Sensitivity of the receptor

  1. The Eyemouth Pontoon would not contribute to impacts on receptors therefore the cumulative effect will therefore be of negligible to minor significance for the Firth of Forth Banks Complex ncMPA receptors and negligible for the Firth of Forth SSSI, Berwickshire and North Northumberland Coast SAC, Berwickshire Coast SSSI, Pease Bay SSSI, St Abb's Head to Fast Castle SSSI and Barns Ness SSSI coastal receptors.

Significance of the effect

  1. Due to the negligible adverse significance of the Eyemouth Pontoon on the Firth of Forth Banks Complex ncMPA receptors and the negligible adverse significance for the coastal receptors, which is not significant in EIA terms.

Further mitigation and residual effect

  1. No physical processes mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section Table 7.14   Open ▸ ) is not significant in EIA terms.
Decommissioning Phase

Magnitude of impact

  1. As with both the operation and maintenance phase and construction phase, the Eyemouth Pontoon has no impact on the assessed receptors.

Sensitivity of the receptor

  1. The Eyemouth Pontoon would not contribute to impacts on receptors therefore the cumulative effect will therefore be of negligible to minor significance for the Firth of Forth Banks Complex ncMPA receptors and negligible for the Firth of Forth SSSI, Berwickshire and North Northumberland Coast SAC, Berwickshire Coast SSSI, Pease Bay SSSI, St Abb's Head to Fast Castle SSSI and Barns Ness SSSI coastal receptors.

Significance of the effect

  1. Due to the negligible adverse significance of the Eyemouth Pontoon on the Firth of Forth Banks Complex ncMPA receptors and the negligible adverse significance for the coastal receptors, which is not significant in EIA terms.

Further mitigation and residual effect

  1. No physical processes mitigation is considered necessary because the predicted impact in the absence of mitigation is not significant in EIA terms.

7.12.4.              Proposed Monitoring

  1. No additional physical processes monitoring to assess the predictions made within the CEA is considered necessary. The project description (volume 1, chapter 3) includes routine inspection and geophysical surveys of wind turbine and OSP/Offshore convertor station platform foundations. Also, offshore export cables, inter-array and interconnector cables burial and protection will be inspected and surveyed as part of the maintenance programme. A commitment has also been made to monitor sandwave recovery following seabed clearance activities to verify the findings of the assessment in concert with Stakeholder agreement.

7.13. Transboundary Effects

  1. A screening of transboundary impacts has been carried out and has identified that there were no likely significant transboundary effects with regard to physical processes from the Proposed Development upon the interests of other European Economic Area (EEA) States. MS-LOT agreed via Scoping that the transboundary impacts of marine physical processes receptors can be scoped out of any further assessment within the Offshore EIA Report however SFF requested that these be included.
  2. During the construction and maintenance phases suspended sediment plumes associated with the installation of foundations, inter-array and offshore export cables do not migrate more than 20 km from the extent of the Proposed Development. Any changes to tidal current, wave climate or associated sediment transport are limited in both magnitude and extent during the operation and maintenance phase. The wave climate shows the widest effect but does not extend northwards of Aberdeen or south of Amble. Furthermore, the potential for cross-border impacts with England has also been considered, as although Scotland and England have different regulatory systems, impacts on English receptors are considered cross-border rather than transboundary. It is worth noting the Proposed Development array area is adjacent to the English marine border. It was concluded that there are no changes in physical processes east of the Greenwich Prime Meridian (Longitude 0º) hence no potential for significant transboundary effects.

7.14. Inter-Related Effects (And Ecosystem Assessment)

  1. A description of the likely inter-related effects arising from the Proposed Development on physical processes is provided in volume 3, appendix 18.1 of the Offshore EIA Report. For physical processes, the following potential impacts have been considered within the inter-related assessment:
  • increased SSCs and associated deposition on physical features; and
  • changes to tidal currents, wave climate, littoral currents and sediment transport.
    1. Table 7.18   Open ▸ lists the inter-related effects (project lifetime effects) that are predicted to arise during the construction, operation and maintenance, and decommissioning of the Proposed Development and also the inter-related effects (receptor-led effects) that are predicted to arise for physical processes receptors.
    2. As previously noted, effects on physical processes also have the potential to have secondary effects on other receptors and these effects are fully considered in the topic-specific chapters. These receptors and effects are:
  • benthic subtidal and intertidal ecology:

–      increased SSC; and

–      sediment deposition.

  • fish and shellfish ecology:

–      increased SSC; and

–      sediment deposition.

  • marine mammals:

–      changes to tidal current and wave climate;

–      increased SSC; and

–      sediment deposition.

  • infrastructure and other users:

–      increased SSC; and

–      changes to tidal current and wave climate.

Table 7.18:
Summary of Likely Significant Inter-Related Effects on the Environment for Physical Processes from Individual Effects Occurring across the Construction, Operation and Maintenance and Decommissioning Phases of the Proposed Development and from Multiple Effects Interacting Across all Phases (Receptor-led Effects)

Table 7.18: Summary of Likely Significant Inter-Related Effects on the Environment for Physical Processes from Individual Effects Occurring across the Construction, Operation and Maintenance and Decommissioning Phases of the Proposed Development and from Multiple Effects Interacting Across all Phases (Receptor-led Effects)

 

7.15. Summary of Impacts, Mitigation Measures, Likely Significant Effects and Monitoring

  1. Information on physical processes within the physical processes study area was collected through a detailed desktop review of existing studies and datasets. These are summarised in Table 7.5   Open ▸ and Table 7.6   Open ▸ respectively. The baseline was characterised by a combination of literature review of the reports and numerical modelling using the datasets. Full details of the analysis undertaken to develop the physical processes baseline is provided in volume 3, appendix 7.1.
  2. Table 7.19   Open ▸ presents a summary of the potential impacts, mitigation measures and the conclusion of likely significant effects on physical processes in EIA terms. The assessment was undertaken for the Proposed Development as described in volume 1, chapter 3 of the Offshore EIA Report. The impacts assessed included increased SSCs and associated deposition as a result of seabed preparation, foundation installation, cable installation, maintenance activity and decommissioning. Additionally, potential changes to tidal flows, wave climate and sediment transport due to the presence of the Proposed Development were also assessed.
  3. The Firth of Forth Banks Complex ncMPA is a composite site with Berwick and Marr Banks lying within the Proposed Development area, whilst Scalp and Montrose Banks, and the Wee Bankie lie within the wider physical processes study area. These banks are comprised of the following designated features; offshore subtidal sands and gravels, shelf banks and moulds and habitat to aggregations of ocean quahog and moraine formations.
  4. Sediment plumes associated with the array installation phase give rise to increased SSCs however these do not persist in the Firth of Forth Banks Complex ncMPA and do not reach Montrose Bank to the north. Sedimentation is limited to immediate vicinity of the installation and would therefore not affect composite banks beyond the development area (i.e. limited to Berwick and Marr Banks). These plumes do not extend to any of the other designated sites with sediment concentrations settling to background levels within the Proposed Development area.
  5. In terms of the Firth of Forth Banks Complex ncMPA, the structure of the offshore subtidal sands and gravels would remain unchanged as the deposition is of native material and the supporting hydrodynamic processes are not altered by the minimal level of bathymetric change as a result of the construction phase sediment releases. Similarly, shelfs, banks and mound features would remain stable and supporting hydrodynamic processes for ocean quahog colonisation remain unaffected.
  6. The offshore export cable trenching corridor does not pass through designated areas, although plumes resulting from the offshore export cable trenching may reach the outer extent of designated sites. The Firth of Forth SSSI is comprised of features such as mudflat, sand dune, saltmarsh and sea cliffs. Barns Ness Coast SSSI contains a variety of coastal features such as saltmarsh, sand dunes and shingle. The Skateraw landfall site for the offshore export cables borders this SSSI, however, as the trenchless technique has been selected and sedimentation from nearshore cabling occurs off Torness Point. This increase sediment material is native to the sediment cell and will therefore not affect geodiversity. The increased sedimentation from the offshore export cables installation causes little or no sedimentation in the intertidal zone which would be insufficient to affect beach morphology.
  7. Changes to tides, waves, littoral currents and sediment transport due to the presence of the infrastructure are experienced in Firth of Forth Banks Complex ncMPA, however changes are concentrated on the specific location of the wind turbine and do not extent beyond the Proposed Development area. Diminutive changes are observed with the littoral current flow due to the installation of the wind farm. Offshore bank and beach morphology would not be influenced by changes of this magnitude. The limited and localised changes to hydrography seen in relation to the Berwick and Marr Banks, would not result in changes to the hydrodynamic regime or sediment composition. The structure of the offshore subtidal sands and gravels would remain unchanged. Similarly, shelfs, banks and mound features would remain stable and supporting hydrodynamic processes for ocean quahog colonisation remain unaffected. Overall, it is concluded that there will be no likely significant effects arising from the Proposed Development during the construction, operation and maintenance or decommissioning phases.
  8. Table 7.20   Open ▸ presents a summary of the potential cumulative effects, mitigation measures and the conclusion of likely significant effects on physical processes in EIA terms. The cumulative assessment included the potential impacts due to adjacent offshore wind farm installations, marine cable installations along with other projects within a 20 km radius. The cumulative effects assessed include increased suspended sediment, sediment deposition and potential changes to littoral currents and sediment transport. Overall, it is concluded that there will be no likely significant cumulative effects from the Proposed Development alongside other projects/plans.
  9. As no likely significant effects were determined, either from the Proposed Development or cumulatively with other projects, no additional mitigating measures have been proposed. However, a commitment has been made to undertake monitoring of sandwave recovery following seabed clearance activities to add to the body of knowledge on the impact of offshore energy infrastructure. Additionally, the project description (volume 1, chapter 3) includes routine inspection and geophysical surveys of wind turbine and OSP/Offshore convertor station platform foundations. Also, offshore export cables, inter-array and interconnector cables burial and protection will be inspected and surveyed as part of the maintenance programme. No potential transboundary impacts have been identified in regard to effects of the Proposed Development.

 

Table 7.19:
Summary of Likely Significant Environmental Effects, Mitigation and Monitoring

Table 7.19: Summary of Likely Significant Environmental Effects, Mitigation and Monitoring


Table 7.20:
Summary of Likely Significant Cumulative Environment Effects, Mitigation and Monitoring

Table 7.20: Summary of Likely Significant Cumulative Environment Effects, Mitigation and Monitoring

7.16. References

ABPmer Ltd et al. (2008). Guidelines in the use of metocean data through the lifecycle of a marine renewables development. CIRIA C666.

Berx, B. and Hughes, S. (2009). Climatology of Surface and Near-bed Temperature and Salinity on the North-West European Continental Shelf for 1971–2000. Elsevier.

British Oceanographic Data Centre (BODC) (2021). UK tide gauge network. Available at: https://www.bodc.ac.uk/data/hosted_data_systems/sea_level/uk_tide_gauge_network/. Accessed on: 16 April 2021.

Brooks, AJ., Whitehead, PA. and Lambkin, DO. (2018). Guidance on Best Practice for Marine and Coastal Physical Processes Baseline Survey and Monitoring Requirements to inform EIA of Major Development Projects. NRW Report No: 243, 119 pp, Natural Resources Wales, Cardiff.

Centre for Environment, Fisheries and Aquaculture Science (Cefas) (2016). Suspended Sediment Climatologies around the UK, CEFAS. Available at: https://data.cefas.co.uk/view/18133. Accessed on: 24 September 2021

DECC (2017). Guidance on Marine Baseline Ecological Assessments and Monitoring Activities for Offshore Renewable Energy Projects Parts 1 and 2.

EMODnet (2021a). EMODnet Bathymetry. Available at: https://www.emodnet-bathymetry.eu/. Accessed on: 6 August 2021.

EMODnet (2021b). EMODnet Geology. Available at: https://www.emodnet-geology.eu/. Accessed on: 10 September 2021.

Fugro (2012). Seagreen Wind Energy Limited: Firth of Forth Zone Development – Metocean Study.

Fugro (2020a). Seagreen 2 and 3 Windfarm Zones Geophysical Survey – Final Survey Results Report – Export Cable Route. Unpublished report for SSE Seagreen Wind Energy Limited, Fugro Document No: P906089-RESULTS-008 (01).

Fugro (2020b). Seagreen 2 and 3 and ECR Windfarm Zone Geophysical Survey – Final Survey Results Report – Seagreen 2 and Seagreen 3. Unpublished report for SSE Seagreen Wind Energy Limited, Fugro Document No: P906089-RESULTS-012 (01).

HM Government (2011). UK Marine Policy Statement. Available at: 10164_Marine Statement_Cov.indd (publishing.service.gov.uk). Accessed on: 21 October 2021.

HR Wallingford (2009). Firth of Forth and Tay Developers Group, Collaborative Oceanographic Survey, Specification and Design. Work Package 1. Review of existing information.

HR Wallingford (2012). Appendix E3 – Geomorphological Assessment. Seagreen Wind Energy. Available at: http://marine.gov.scot/datafiles/lot/SG_FoF_alpha-bravo/SG_Phase1_Offshore_Project_Consent_Application_Document%20(September%202012)/006%20ES/Volume%20III_Technical%20Appendices/Part%201_Technical%20Appendices/Appendix%20E3.pdf Accessed: September 2021.

Intertek METOC (2011). Coastal Processes Assessment for Neart na Gaoithe Offshore Wind Farm Technical Report.

JNCC (2021). Marine Protected Areas and Designations. Available at: https://jncc.gov.uk/mpa-mapper/. Accessed on: 24 September 2021.

Lambkin, D.O., Harris, J.M., Cooper, W.S. and Coates, T. (2009). Coastal Process Modelling for Offshore Wind Farm Environmental Impact Assessment. Collaborative Offshore Wind Energy Research into the Environment (COWRIE).

Mainstream Renewable Power Limited (2012). Neart na Gaoithe Offshore Wind Farm Environmental Statement.

Marine Environmental Data Information Network (MEDIN) (2021). Bathymetry data. Available at: https://data.admiralty.co.uk/portal/apps/sites/#/marine-data-portal. Accessed on: March 2021.

 

Marine Scotland mapping data (2021). Marine Features. Available at: https://marinescotland.atkinsgeospatial.com/nmpi/. Accessed on: September 2021.

Pye, K., Blott, S.J. and Brown, J. (2017). Advice to Inform Development of Guidance on Marine, Coastal and Estuarine Physical Processes Numerical Modelling Assessments. NRW Report No 208, 139pp, Natural Resources Wales.

Ramsay and Brampton (2000). Coastal Cells in Scotland: Cell 1 - St Abb's Head to Fife Ness. Available at: http://www.dynamiccoast.com/resources. Accessed on: September 2021.

School of Geographical and Earth Sciences (2021). Dynamic Coast. Available at: https://www.dynamiccoast.com. Accessed on: September 2021.

Scottish Government (2015). Scotland’s National Marine Plan A Single Framework for Managing Our Seas. Available at: Scotland's National Marine Plan - gov.scot (www.gov.scot). Accessed on: 21 October 2021.

Scottish Government (2020). Sectoral Marine Plan for Offshore Wind Energy. Available at: Sectoral Marine Plan for Offshore Wind Energy (www.gov.scot). Accessed on: 21 October 2021.

SSER (2021a). Berwick Bank Wind Farm Offshore Scoping Report.

SSER (2022b). Berwick Bank Wind Farm Marine Protected Area (MPA) Assessment.

SSER (2022c). Berwick Bank Wind Farm Report to Inform Appropriate Assessment (RIAA).

SSER (2022e). Cambois connection Scoping Report.

XOCEAN Ltd (2021). 00338 SSE Berwick Bank Lot 1 and 2 Operations and Results Report. Unpublished report for SSER.

 

[1] Meeting on 26 April 2022 between MS-LOT, RPS and the Applicant

[2] C = Construction, O = Operation and maintenance, D = Decommissioning

[3] C = Construction, O = Operation and maintenance, D = Decommissioning

[4] C = Construction, O = Operation and maintenance, D = Decommissioning