11.5 Information to Inform Assessment of Adverse Effects on Integrity
11.5.1 Berwickshire and North Northumberland Coast SAC
European Site information
167 The Berwickshire and North Northumberland Coast SAC extends from Alnmouth in north-east England to north of St Abbs head in Scotland and is located 34.69 km from the Proposed Development array area and 4.14 km from the Proposed Development export cable corridor. The site contains a complex mix of marine habitats, associated species and communities which is unusually diverse for the North Sea. The SAC is designated for the following Annex I habitats: large shallow inlets and bays; mudflats and sandflats not covered by seawater at low tide; reefs; and submerged or partially submerged sea caves.
168 A feature condition assessment was undertaken in 2014 and submerged or partially submerged sea caves were assessed as “favourable maintained[7]”. The condition of the SAC’s other Annex I features has not been assessed at the time of writing.
169 Further information on this European site is presented in appendix A.
Conservation objectives
170 The conservation objectives for the Berwickshire and North Northumberland Coast SAC have been developed by Natural England and NatureScot and apply to the site and the individual species and/or assemblage of species for which the site has been classified. These high-level objectives are to ensure that, subject to natural change, the integrity of the site is maintained or restored as appropriate, and that the site contributes to achieving the Favourable Conservation Status of its Qualifying Features, by maintaining or restoring:
- the extent and distribution of qualifying natural habitats and habitats of qualifying species;
- the structure and function (including typical species) of qualifying natural habitats;
- the structure and function of the habitats of qualifying species;
- the supporting processes on which qualifying natural habitats and the habitats of qualifying species rely;
- the populations of qualifying species; and,
- the distribution of qualifying species within the site.
171 Supplementary advice on conservation objectives, last updated by Natural England and NatureScot on 13 March 2020, provide the site-specific attributes and targets specific to the Annex I habitat features of the site.
172 The attribute targets show that the current objective is to ‘maintain’ the attributes for each Annex I feature. These supplementary attributes and targets are considered in the assessments below and are provided for reference in appendix A.
Features and effects for assessment
173 Table 11.6 Open ▸ summarises the LSEs that were identified for the Annex I habitat features of the Berwickshire and North Northumberland Coast SAC and the features and effects which have been considered in the assessment of adverse effects on Integrity for this site. Table 11.6 Open ▸ also takes account of the project specific assessment information presented in sections 7.1 and 11.4 and where modelling has demonstrated no pathway to effect for particular features.
Table 11.6: Summary of Features and Effects Considered in the Assessment of Adverse Effects on Integrity for the Berwickshire and North Northumberland Coast SAC
Construction and decommissioning
Increased SSC and associated sediment deposition
Mudflats and sandflats not covered by seawater at low tide
174 As discussed in section 11.3.1, pre installation sand wave clearance and installation of the offshore export cables will lead to increases in SSC and associated sediment deposition. As outlined in paragraph 115, however, the qualifying Annex I habitat mudflats and sandflats not covered by seawater at low tide feature of the Berwickshire and North Northumberland Coast SAC are located out with the predicted ZoI of increased SSC and sediment deposition. There is, therefore, considered to be no pathway to effect on the Annex I habitat mudflats and sandflats not covered by seawater at low tide feature as a result of increased SSC and sediment deposition. Effects arising from SSC and sediment deposition, as a result of the construction and decommissioning of the Proposed Development will not undermine the conservation objectives for this feature.
175 The extent and distribution of the mudflats and sandflats not covered by seawater at low tide feature will not be reduced, and the population and distribution of qualifying species will not be reduced. The supporting processes on which the Annex I mudflats and sandflats not covered by seawater at low tide feature rely will also not be adversely affected. The structure and function of mudflats and sandflats not covered by seawater at low tide feature will be unaffected. There will be no significant adverse effects on the qualifying Annex I habitat mudflats and sandflats not covered by seawater at low tide feature of the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts during the construction or decommissioning phases.
Large shallow inlets and bays
177 The extent and distribution of the large shallow inlets and bays feature will not be reduced, and the population and distribution of qualifying species will not be reduced. The supporting processes on which the feature rely will also not be adversely affected. The structure and function of the large shallow inlets and bays feature will be unaffected. There will be no significant adverse effects on the qualifying Annex I habitat large shallow inlets and bays feature of the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts during the construction or decommissioning phases.
Reefs
178 As discussed in section 11.2.5, subtidal reefs within the Berwickshire and North Northumberland Coast SAC include the sub-features kelp forest communities and subtidal faunal turf communities. These sub features of the reef have been assessed as having medium sensitivity to smothering and siltation rate change and water quality changes. Siltation can clog or block feeding/respiratory organs of animals, and increased water turbidity influences the ability of kelp and other algal species to photosynthesise. Intertidal species can also be adversely affected by reduced water clarity and siltation rate changes and have been assessed as having medium sensitivity to the impact.
179 The results of project specific modelling, discussed in paragraphs 110 to 112, shows that sedimentation at the coastline is predicted to be typically <3 mm and SSCs are predicted to reduce to background levels on slack tides. The Berwickshire and North Northumberland Coast SAC site is located 4.12 km from the Proposed Development export cable corridor, therefore the effects resulting from changes to water quality and light smothering and siltation rate change will be reduced due to dispersal.
180 The extent and distribution of the Annex I reefs feature will not be reduced, and the population and distribution of qualifying species will not be reduced. The supporting processes on which the Annex I reef feature rely will also not be adversely affected. The structure and function of the reef habitats will also be unaffected. Given the above, there will be no significant adverse effects on the qualifying Annex I reefs feature of the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts during the construction or decommissioning phases.
Submerged or partially submerged sea caves
182 The results of project specific modelling, discussed in paragraphs 110 to 112, shows that sedimentation at the coastline to be typically <3 mm and SSCs are predicted to reduce to background levels on slack tides. The Berwickshire and North Northumberland Coast SAC is located 4.12 km from the Proposed Development export cable corridor, therefore the effects resulting from changes to water quality and light smothering and siltation rate change will be reduced due to dispersal.
183 The extent and distribution of habitats associated with the Annex I submerged or partially submerged sea caves feature will not be reduced, and the population and distribution of qualifying species will not be reduced. The structure and function of the submerged or partially submerged sea cave habitats will be unaffected. The supporting processes on which the Annex I feature rely will also not be adversely affected. Given the above, therefore will be no significant adverse effects on the qualifying Annex I submerged or partially submerged sea caves feature of the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts during the construction or decommissioning phases.
Conclusion
184 The assessment has concluded that there is no pathway to effect for increased SSC and sediment deposition on the Annex I mudflats and sandflats not covered by seawater at low tide feature or the Annex I large shallow inlets and bays feature during the construction and decommissioning phases. As such, the conservation objectives will not be undermined for these features. For the Annex I reefs and Annex I submerged or partially submerged sea caves features, there is no direct spatial overlap of the Proposed Development and the site, so the extent and distribution of habitats associated with these features will not be reduced, and neither will be the population and distribution of qualifying species. Given that levels of increased SSC and deposition predicted at the coast are very low, the structure and function of the features will be unaffected and the supporting processes will be maintained.
185 Therefore, it can be concluded that there is no risk of an adverse effect on the integrity on the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts with respect to the construction and decommissioning of the Proposed Development acting alone.
Operation and maintenance
Increased SSC and associated sediment deposition
186 As detailed in section 11.4.1, maintenance activities associated with the offshore export cable may lead to increases in SSCs and associated sediment deposition over the operational lifetime of the Proposed Development. For the offshore export cables the total length of works would be approximately 0.4% of the length assessed for the construction phase with events being undertaken over the Proposed Developments lifetime. The sediment plumes and sedimentation footprints would be dependent on which section of the cable is being repaired. For the purposes of this assessment, the impacts of the operation and maintenance activities (i.e. cable repair and reburial) are predicted to be no greater than those for construction but in reality, given the reduced scale of the works associated with maintenance, will be of a lower magnitude compared to construction.
Mudflats and sandflats not covered by seawater at low tide
187 As outlined in paragraph 115, the qualifying Annex I habitat mudflats and sandflats not covered by seawater at low tide feature of the Berwickshire and North Northumberland Coast SAC are located out with the predicted ZoI of increased SSC and sediment deposition. There is, therefore, considered to be no pathway to effect on the Annex I habitat mudflats and sandflats not covered by seawater at low tide feature as a result of increased SSC and sediment deposition during the operation and maintenance phase. Effects arising from SSC and sediment deposition, as a result of the operation and maintenance of the Proposed Development will not undermine the conservation objectives for this feature.
188 The extent and distribution of the mudflats and sandflats not covered by seawater at low tide feature will not be reduced, and the population and distribution of qualifying species will not be reduced. The structure and function of the mudflats and sandflats not covered by seawater at low tide feature will be unaffected. The supporting processes on which the Annex I mudflats and sandflats rely will also not be adversely affected. There will, therefore, be no significant adverse effects on the qualifying Annex I habitat mudflats and sandflats not covered by seawater at low tide feature of the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts during the operation and maintenance phase.
Large shallow inlets and bays
189 The Berwickshire and North Northumberland Coast SAC is located 4.12 km from the Proposed Development export cable corridor, and the qualifying Annex I large shallow inlets and bays feature of the Berwickshire and North Northumberland Coast SAC are located out with the predicted ZoI of increased SSC and sediment deposition. There is, therefore, considered to be no pathway to effect on the Annex I large shallow inlets and bays feature as a result of increased SSC and sediment deposition as a result of maintenance activities. Effects arising from SSC and sediment deposition, as a result of the operation and maintenance of the Proposed Development will not undermine the conservation objectives for this feature.
190 The extent and distribution of the habitats associated with the large shallow inlets and bays feature, and the population and distribution of qualifying species will not be reduced. The supporting processes on which the feature rely will also not be adversely affected. The structure and function of habitats associated with the large shallow inlets and bays feature will be unaffected. There will, therefore, be no significant adverse effects on the qualifying Annex I habitat large shallow inlets and bays feature of the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts during the operation and maintenance phase.
Reefs
191 The impact of increased SSC and associated sediment deposition on reefs will be the same or less than those predicted for construction and decommissioning (see paragraph 179 for a summary and section 11.3.1 for full details). The sensitivity of this Annex I habitat to this impact will also be the same as that described for construction and decommissioning (see paragraphs 118 to 121, and paragraph 178 for a summary).
192 The extent and distribution of the Annex I reefs feature, and the population and distribution of qualifying species will not be reduced as there is no physical overlap between the Proposed Development and the site. The results of project specific modelling, discussed in paragraphs 110 to 112, shows that, the supporting processes on which the Annex I reefs feature rely will also not be adversely affected. The structure and function of reefs will be unaffected. There will, therefore, be no significant adverse effects on the qualifying Annex I reefs feature of the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts during the operation and maintenance phase.
Submerged or partially submerged sea caves
193 The impact of increased SSC and associated sediment deposition on submerged or partially submerged sea caves will be the same or less than those predicted for construction and decommissioning (see paragraph 182 for a summary and section 11.3.1 for full details). The sensitivity of this Annex I habitat to this impact will also be the same as that described for construction and decommissioning (see paragraphs 122 to 123, and paragraph 181 for a summary).
194 Significant adverse effects on the qualifying Annex I habitat submerged or partially submerged sea caves of the Berwickshire and North Northumberland Coast SAC are not predicted to occur as a result of increased SSC and associated sediment deposition impacts during operation and maintenance. The extent and distribution of the habitats associated with submerged or partially submerged sea caves, and the population and distribution of qualifying species will not be reduced. The structure and function of habitats associated with submerged or partially submerged sea caves will be unaffected. The supporting processes on which the Annex I feature rely will also not be adversely affected.
Conclusion
195 The assessment has concluded that there is no pathway to effect for increased SSC and sediment deposition on the Annex I mudflats and sandflats not covered by seawater at low tide feature or the Annex I large shallow inlets and bays feature during the operation and maintenance phase, As such, the conservation objectives will not be undermined for these features. For the Annex I reefs and Annex I submerged or partially submerged sea caves features, there is no direct spatial overlap of the Proposed Development and the site, so the extent and distribution of habitats associated with these features will not be reduced, and neither will be the population and distribution of qualifying species. Given that levels of increased SSC and deposition predicted at the coast are very low and will likely be lower than those arising during the construction phase, the structure and function of the features will be unaffected and the supporting processes will be maintained.
196 Therefore, it can be concluded that there is no risk of an adverse effect on the integrity of the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts with respect to the operation and maintenance of the Proposed Development acting alone.
Alteration of seabed habitats arising from effects of physical processes
197 As discussed in section 11.4.2, alteration of seabed habitats may arise from the effects of changes to physical processes, including scour effects and changes in the sediment transport and wave regimes resulting in potential effects on benthic receptors. As detailed in section 11.4.2, the modelling presented in volume 3, appendix 7.1 of the offshore EIA Report demonstrates that tidal flows will not be affected in the nearshore. For some wave climates (predominately storms approaching from the northerly sectors), there is predicted to be a very small change at the coast, but these are for specific storm directions and would be imperceptible from natural variation. The combination of the two (littoral currents) and thus the impact on sediment transport is also not predicted to give rise to any discernible change in physical processes at the coast and, therefore, within the Berwickshire and North Northumberland Coast SAC.
Mudflats and sandflats not covered by seawater at low tide
198 Whilst mudflats and sandflats not covered by seawater at low tide have been assessed to have medium sensitivity to this impact, as outlined in paragraphs 148 to 152 modelling has demonstrated that changes to tides, waves, littoral currents and sediment transport due to the presence of the infrastructure are not predicted to extend to the Berwickshire and North Northumberland Coast SAC. Any changes to physical processes are predicted to be localised around the array structures.
199 The extent and distribution of the mudflats and sandflats not covered by seawater at low tide feature will not be reduced as a result of this impact, and the population and distribution of qualifying species will not be reduced. Given that impacts on physical processes are predicted to be largely localised within the Proposed Development array area, the supporting processes on which the Annex I mudflats and sandflats not covered by seawater at low tide feature rely will also not be adversely affected. The structure and function of mudflats and sandflats will be unaffected. There will, therefore, be no significant adverse effects on the qualifying Annex I habitat mudflats and sandflats not covered by seawater at low tide feature of the Berwickshire and North Northumberland Coast SAC are not predicted to occur as a result of alteration of seabed habitats arising from effects of physical processes impacts during operation.
Large shallow inlets and bays
200 Large shallow inlets and bays has been assessed as being of negligible sensitivity to this impact. As outlined in paragraphs 148 to 152 modelling has demonstrated that changes to tides, waves, littoral currents and sediment transport due to the presence of the infrastructure are not predicted to extend to the Berwickshire and North Northumberland Coast SAC.
201 The extent and distribution of habitats associated with the large shallow inlets and bays feature will not be reduced as a result of this impact, and the population and distribution of qualifying species will not be reduced. Given that impacts on physical processes are predicted to be largely localised within the Proposed Development array area, the supporting processes on which the feature rely will also not be adversely affected. The structure and function of the habitats associated with the large shallow inlets and bays feature will be unaffected. There will, therefore, be no significant adverse effects on the qualifying Annex I large shallow inlets and bays feature of the Berwickshire and North Northumberland Coast SAC as a result of alteration of seabed habitats arising from changes in physical processes during the operation and maintenance phase.
Reefs
202 As described in paragraphs 159 to 162, reefs have been assessed to have medium sensitivity to this impact. Modelling has, however, demonstrated that changes to tides, waves, littoral currents and sediment transport due to the presence of the infrastructure are not predicted to extend to the Berwickshire and North Northumberland Coast SAC. Any impacts on physical processes are predicted to be localised around the array structures.
203 The extent and distribution of the reefs feature will not be reduced as a result of this impact, and the population and distribution of qualifying species will not be reduced. Given that impacts on physical processes are predicted to be largely localised within the Proposed Development array area, the supporting processes on which the Annex I reef feature rely will also not be adversely affected. The structure and function of the reefs feature will be unaffected. There will, therefore, be no significant adverse effects on the qualifying Annex I reefs feature of the Berwickshire and North Northumberland Coast SAC as a result of alteration of seabed habitats arising from changes in physical processes during the operation and maintenance phase.
Submerged or partially submerged sea caves
204 As described in paragraphs 163 to 166, submerged or partially submerged sea caves has been assessed as being of negligible sensitivity to this impact. Modelling has also demonstrated that changes to tides, waves, littoral currents and sediment transport due to the presence of the infrastructure are not predicted to extend to Berwickshire and North Northumberland Coast SAC.
205 The extent and distribution of habitats associated with the Annex I submerged or partially submerged sea caves feature will not be reduced as a result of this impact, and the population and distribution of qualifying species will also not be reduced. The structure and function of the habitats associated with the Annex I submerged or partially submerged sea caves feature will be unaffected. Given that impacts on physical processes are predicted to be largely localised within the Proposed Development array area, the supporting processes on which the Annex I feature rely will also not be adversely affected. There will, therefore, be no significant adverse effects on the qualifying Annex I submerged or partially submerged sea caves feature of the Berwickshire and North Northumberland Coast SAC as a result of alteration of seabed habitats arising from changes in physical processes during the operation and maintenance phase.
Conclusion
206 The assessment has concluded that there is no direct spatial overlap between the Proposed Development and the Berwickshire and North Northumberland Coast SAC, and so for all Annex I habitat features assessed, there is no risk of the extent and distribution conservation objectives being hindered. Similarly, the habitats associated with these features will not be reduced, and neither will be the population and distribution of qualifying species. Given that any changes to tides, waves, littoral currents and sediment transport due to the presence of the infrastructure are predicted to be localised and to not extend to the site, the structure and function of the features will be unaffected and the supporting processes will be maintained.
207 Therefore, it can be concluded that there is no risk of an adverse effect on the integrity of the Berwickshire and North Northumberland Coast SAC from changes in physical processes with respect to the operation and maintenance of the Proposed Development acting alone.
Effects in-combination
208 An assessment of in-combination effects upon the qualifying Annex I habitats of the Berwickshire and North Northumberland Coast SAC arising from each identified impact is provided below.
Assessment of in-combination effects during construction and decommissioning
Increased Suspended Sediment Concentrations and Associated Sediment Deposition
209 There is potential for in-combination effects from increased SSC and associated sediment deposition to Annex I habitats during the construction phase of the Proposed Development with activities associated with the following projects:
- Tier 2:
– Inch Cape Offshore Wind Farm (construction and operation and maintenance phases);
– Seagreen 1 (operation and maintenance phase only);
– Seagreen 1A Project (construction and operation and maintenance phases);
– Seagreen 1A Export Cable Corridor (operation and maintenance phase);
– Neart na Gaoithe Offshore Wind Farm (operation and maintenance phase only);
– Eastern Link 1 (construction and operation and maintenance phases);
– Eastern Link 2 (construction and operation and maintenance phases); and
– Eyemouth disposal site.
- Tier 3:
– Cambois connection (construction and operation and maintenance phases).
210 During the decommissioning phase of the Proposed Development, there is potential for in-combination effects from increased SSC and associated sediment deposition to Annex I habitats with activities associated with the following projects:
- Tier 2:
– Decommissioning of Inch Cape Offshore Wind Farm);
– Decommissioning of Neart na Gaoithe Offshore Wind Farm;
– Decommissioning of Seagreen 1;
– Decommissioning Seagreen 1A Project;
– Decommissioning Seagreen 1A Export Cable Corridor; and
– Use of Eyemouth disposal site.
- Tier 3:
– Decommissioning of Cambois connection.
Tier 2
211 As described in paragraph 113, increases in SSC and associated sediment deposition arising from the installation of wind turbines and OSP/Offshore convertor station platform foundations, inter-array cables and offshore export cables during the construction phase, have been assessed as being of negligible magnitude on features of the Berwickshire and North Northumberland Coast SAC as a result of the Proposed Development alone. Impacts of increased SSC and associated sediment deposition are predicted to be negligible within the Berwickshire and North Northumberland Coast SAC given most sediment deposition will be localised, focussed within the Proposed Development export cable corridor. Any fines reaching the coast within the SAC are predicted to be <3 mm in thickness and SSCs are predicted to reduce to background levels on slack tides. Furthermore, as outlined in paragraph 115 and paragraph 117 respectively, the qualifying Annex I mudflats and sandflats not covered by seawater at low tide feature and the Annex I large shallow inlets and bats feature of the Berwickshire and North Northumberland Coast SAC are located out with the predicted ZoI of increased SSC and sediment deposition from the Proposed Development alone.
212 Seagreen 1A Project will be installing wind turbines until the end of 2025 which will overlap with the construction phase of the Proposed Development. The Inch Cape Offshore Wind farm will be in the final year of construction, with the programme for the installation of the offshore export cable overlapping with the Proposed Development. Neart na Gaoithe Offshore Wind Farm and the Seagreen 1A Export Cable Corridor will be in operational phase and maintenance activities during the construction phase of the Proposed Development. All of these projects are located further from the Berwickshire and North Northumberland Coast SAC than the Proposed Development export cable corridor. Sediment plumes arising from installation of the Inch Cape Offshore Wind Farm are not predicted to interact with those from the Proposed Development and increases in SSC from maintenance activities at other offshore wind farm projects in Tier 2 would be of limited spatial extent and frequency and unlikely to interact with sediment plumes from the Proposed Development.
213 Eastern Link 2 is also further away from the SAC than the Proposed Development and although Eastern Link 1 is closer to the SAC than the Proposed Development, any increases in SSC and associated sediment deposition reaching the SAC will be similarly temporary and negligible as the Proposed Development and therefore not predicted to result in notable in-combination effects.
214 Although the Eyemouth disposal site is close to the Berwickshire and North Northumberland Coast SAC at 0.88 km distance to the east, it is located 16.5 km from the Proposed Development export cable corridor. If offshore cable installation and dredge material disposal coincided, both resultant plumes would be advected on the tidal currents, they would travel in parallel, and not towards one another, and are unlikely to interact in the event that offshore cable installation coincides with the use of the licensed sea disposal site.
215 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts with respect to the Proposed Development acting in-combination with Tier 2 projects.
Tier 3
216 During the construction phase of the Proposed Development there is the potential for cumulative impacts with one Tier 3 cable installation. The Cambois connection is a 170 km cable route extending southwards from the Proposed Development array area. Scoping indicates the project will consist of up to four cables installed in 2 m wide trenches up to 3 m in depth. Installation techniques may include jet trenching, cable ploughing and mass flow excavator, as ground conditions dictate. Site preparation will be required, such as boulder and sand wave clearance as part of the approximately two year construction programme. Any increases in SSC and associated sediment deposition reaching the SAC will be similarly temporary and negligible to the Proposed Development and therefore not result in significant in-combination effects. Additionally, the Cambois connection export cable corridor approach to the landfall is south of the SAC compared with the Proposed Development export cable corridor which is north of the SAC therefore any increases in SSC from these projects are unlikely to interact or result in anything other than negligible increases in SSC and sediment deposition within the SAC as a whole.
217 During the decommissioning phase of the Proposed Development all structures above the seabed would be removed. It is proposed to remove all export, inter-array and inter-connector cables and scour protection where possible and appropriate to do so. During decommissioning cables would be removed by similar processes as undertaken during installation therefore increases in SSC would be of a similar form and magnitude. Following decommissioning, changes in suspended sediments concentration and sedimentation would return to baseline levels as it is anticipated that all structures above the seabed level will be completely removed and no further operation to disturb the seabed would be required. Therefore, the assessment described for the construction phase above is deemed equally applicable for the decommissioning phase.
218 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts with respect to the Proposed Development acting in-combination with Tier 3 projects.
Assessment of in-combination effects during operation and maintenance
Increased Suspended Sediment Concentrations and Associated Sediment Deposition
219 There is potential for in-combination effects from increased SSC and associated sediment deposition to Annex I habitats during the operation and maintenance phase of the Proposed Development with activities associated with the following projects:
- Tier 2:
– Inch Cape Offshore Wind Farm (operation and maintenance phase only);
– Seagreen 1 (operation and maintenance phase only);
– Seagreen 1A (operation and maintenance phase only);
– Neart na Gaoithe Offshore Wind Farm (operation and maintenance phase only);
– Eastern Link 1 (operation and maintenance phase only);
– Eastern Link 2 (operation and maintenance phase only); and
– Eyemouth disposal site.
- Tier 3:
– Cambois connection (operation and maintenance phase only).
Tier 2
220 As described in paragraph 135, increases in SSC and associated sediment deposition arising from the maintenance of offshore export cables for the Proposed Development alone has been assessed as being of negligible magnitude on features of the Berwickshire and North Northumberland Coast SAC. During the operation and maintenance phase of the Proposed Development there is the potential for in-combination effects with the maintenance activities at other offshore wind farms, any required maintenance of the Eastern Link 1 and Eastern Link 2 cables, and use of the Eyemouth disposal site. Any increases in SSC and associated sediment deposition as a result of maintenance activities will be temporary, intermittent and highly localised. Any increases reaching the SAC will be similarly temporary and negligible as the Proposed Development and therefore not result in significant in-combination effects.
221 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts with respect to the Proposed Development acting in-combination with Tier 2 projects.
Tier 3
222 During the operation and maintenance phase of the Proposed Development there is the potential for in-combination effects with the maintenance activities with all Tier 2 projects and also maintenance of the Cambois connection. Maintenance activities may result in increased SSC; however, these activities would be of limited spatial extent and frequency and lower in magnitude than the construction phase. Any increases reaching the SAC will be similarly temporary and negligible as the Proposed Development and therefore not result in significant in-combination effects.
223 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Berwickshire and North Northumberland Coast SAC as a result of increased SSC and associated sediment deposition impacts with respect to the Proposed Development acting in-combination with Tier 3 projects.
Alteration of seabed habitats arising from effects of physical processes
- Tier 2:
– Inch Cape Offshore Wind Farm (52.0 km from the SAC);
– Seagreen 1 (64.5 km from the SAC);
– Seagreen 1A Project (66.6 km from the SAC); and
– Neart na Gaoithe Offshore Wind Farm(28.5 km from the SAC).
Tier 2
225 As described in paragraph 154, changes in physical processes for the Proposed Development alone has been assessed as being of negligible magnitude on features of the Berwickshire and North Northumberland Coast SAC.
226 Assessment of the Proposed Development was carried out with and without the presence of infrastructure. It can be inferred that during the construction phase there will be gradual changes to tidal currents, wave climate, littoral currents and sediment transport as infrastructure is built. With changes occurring from the baseline environment (no presence of infrastructure) to the operation and maintenance phase (maximum design scenario). This would also be the case for the offshore wind farm developments under construction during this period (i.e. Inch Cape and Seagreen 1A Project). Although, construction of subsea elements such as foundations and cable installation will be largely completed prior to commencing the construction phase of the Proposed Development.
227 The introduction of wind farm infrastructure into areas of predominantly soft sediments has the potential to alter the seabed through changes in the physical processes. This impact is only relevant to the operation and maintenance phase.
228 The modelling and assessment for Neart na Gaoithe included Neart na Gaoithe, Inch Cape, Seagreen 1, and the Seagreen 1A Project in addition to the Proposed Development which is referred to in the documentation as Seagreen Phase 2 and Phase 3. Within the modelling, the Proposed Development was modelled with 725 wind turbines each with an 8 m tower diameter relating to 6 MW devices. The Proposed Development however incorporates a maximum of 307 wind turbines which is significantly less than the scenario modelled and therefore the impacts would, in reality, be less than those reported. The impact of multiple developments on tidal currents was predicted by the study to be low and localised to the near field of each development.
229 The Neart na Gaoithe study also showed that with all offshore wind farms in situ, the cumulative impact on the wave climate is low (<3% average significant wave height) but the effect on wave climate has a larger extent than a single offshore wind farm. The cumulative impact from the combined wind farm developments on sediment transport processes is low, resulting in a 1% to 3% exceedance in the typical critical bed shear stress. Changes are within the immediate vicinity of each of the developments and it is not expected that there would be changes to the far field sediment regimes.
230 Given the other offshore wind farm projects are further from the Berwickshire and North Northumberland Coast SAC than the Proposed Development (see paragraph 224) no significant in-combination effects from this impact are anticipated.
231 Therefore, it can be concluded that there is no risk on an Adverse Effect on Integrity on the Berwickshire and North Northumberland Coast SAC as a result of alteration of seabed habitats arising from effects of physical processes potential impact can be concluded with respect to the Proposed Development acting in-combination with Tier 2 projects.