Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Operation and maintenance phase
Magnitude of impact
  1. There were three Tier 3 projects identified within the 50 km buffer considered for potential for cumulative effects associated with this impact:
  • Bellrock Offshore Wind Farm;
  • Bowdun Offshore Wind Farm;
  • Campion Offshore Wind Farm, and
  • Morven BP-EnBW Offshore Export Cable Corridor.
  1. Tier 3 projects are in a pre-application phase and no EIA Scoping Report or EIA Report is available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
  2. As described in paragraph 786, maintenance of cables or turbines typically involves considerably smaller numbers of vessels and round trips compared to construction. Considering the vessel activity within the North Sea, it is anticipated that these will not add substantially to the number of vessels present during the operation and maintenance phases of the Array, Tier 1 and Tier 2 projects and that the potential for cumulative effects is unlikely.
  3. It should also be considered that during the operation and maintenance phase of the Array some of the Tier 3 projects may be decommissioned. There may be an increase in vessel numbers associated with the decommissioning phases of the Tier 3 projects outlined above. However, as outlined in paragraph 839, considering the vessel activity within the North Sea, it is anticipated that these will not add substantially to the number of vessels present during the operation and maintenance phases of the Array.
  4. The cumulative impact (elevated underwater noise during vessel use and other noise producing activities) is predicted to be of local to regional spatial extent in the context of the geographic frame of reference, long term duration, intermittent and the effect of behavioural disturbance is of high reversibility (with animals returning to baseline levels soon after they moved from the impact zone). It is predicted that the impact will affect the receptor directly. Whilst there may be effects at an individual level, these are not predicted to be at a scale that would lead to any population-level effects. The magnitude was therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivities of marine mammals to cumulative disturbance from elevated underwater noise during vessel activity and other noise producing activities are as previously described for the assessment of the Array alone (paragraph 396) for the construction phase and therefore is not repeated here.
  2. All marine mammals are deemed to have some resilience to cumulative behavioural disturbance from vessel noise, high recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Decommissioning phase
Magnitude of impact
  1. There were three Tier 3 projects identified within the 50 km buffer considered for potential for cumulative effects associated with this impact:
  • Bellrock Offshore Wind Farm;
  • Bowdun Offshore Wind Farm;
  • Campion Offshore Wind Farm; and
  • Morven BP-EnBW Offshore Export Cable Corridor.
  1. The decommissioning timescale for Tier 3 projects is currently unknown. On the basis of a 35 year operational lifetime, decommissioning will not occur at the Array until 2074. There is therefore unlikely to be temporal overlap between Tier 3 projects currently in pre-planning stage (i.e., not submitted a scoping report) and decommissioning at the Array. Cumulative effects from underwater noise generated during vessel use and other noise producing activities are not anticipated.
  2. The cumulative impact (elevated underwater noise during vessel use and other noise producing activities) is predicted to be of local to regional spatial extent in the context of the geographic frame of reference, medium-term duration, intermittent and the effect of behavioural disturbance is of high reversibility (with animals returning to baseline levels soon after they moved from the impact zone). It is predicted that the impact will affect the receptor directly. Whilst there may be effects at an individual level, these are not predicted to be at a scale that would lead to any population-level effects. The magnitude was therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivities of marine mammals to cumulative disturbance from site-investigation surveys are as previously described above for the assessment of the array alone (paragraphs 395 to 411) for the construction phase and therefore is not repeated here.
  2. All marine mammals are deemed to have some resilience to cumulative behavioural disturbance from vessel noise, high recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Injury Due To Collision With Vessels

                        Tier 1

Construction phase
Magnitude of impact
  1. One Tier 1 project was identified with potential for cumulative effects associated with this impact within the 50 km buffer, in the regional marine mammal study area:
  • Proposed offshore export cable corridor(s) (construction and operation and maintenance phases).
  1. As discussed in paragraph 590, there is uncertainty of the final design and location details of the Proposed offshore export cable corridor(s) and therefore it is not possible to provide a quantitative assessment but it can be reasonably assumed injury due to collision with vessels is scoped in and will be assessed in the Proposed offshore export cable corridor(s) EIA.
  2. High volumes of vessel traffic during construction of the Array have the potential to increase interaction (such as collision or noise disturbance) with marine mammals (see paragraph 443), with the severity of resulting injury generally correlated with the vessel speed. As many as 7,902 return vessel movements may be made during the construction phase within the Array marine mammal study area. With all vessels adhering to the rules (e.g. maximum speeds, no abrupt changes in course etc.) proposed within the NSVMP, volume 4, appendix 24 the risk of collision is anticipated to be reduced, the risk would only be present for transiting vessels to/from and within the Array; with the sound emitted likely to deter animals from the potential zone of impact. The impact during the construction phase is predicted to be localised and intermittent for a medium term duration. It is predicted to affect sensitive receptors directly with medium to low reversibility. The magnitude is therefore considered to be low.
  3. The number and types of vessels associated with construction of Array as well as construction and/or operation and maintenance of projects considered in the CEA is provided in paragraph 786 et seq. Given that vessel movements will be confined to the array areas and/or offshore export cable corridor routes and will follow existing shipping routes to/from port, the risk of collision to marine mammals is expected to be localised to within the boundaries of the respective CEA projects. The types of vessels involved in construction activities at the other offshore wind farms will be similar to those identified for construction of the Array (such as those described in paragraph 776). As previously described for the Array alone (see paragraph 446 et seq.), vessels travelling at 7 m/s or faster are those most likely to cause death or serious injury to marine mammals (Laist et al., 2001). Vessels involved in the construction phase of Array and respective projects are likely to be travelling considerably slower than this, and will be required to adhere to the NSVMP, volume 4, appendix 24 which includes not deliberately approaching marine mammals as a minimum, to avoid abrupt changes in course or speed should marine mammals approach the vessel to bow-ride and remain at safe speeds at all times (as detailed in Table 10.22   Open ▸ ). There is also a potential that the noise emissions from vessels will deter animals from the potential zone of impact.
  4. The Array and respective projects are located in the area of relatively high vessel traffic, particularly cargo vessels (see paragraph 387 et seq.) and therefore it can be expected that marine mammals present in the vicinity of Firth of Forth will demonstrate some degree of habituation to the presence of high number of vessels. Furthermore, the Array is located in proximity to oil and gas structures in the North Sea and as such the traffic of oil and gas vessels is substantial. Considering the baseline levels of vessel traffic, it can be anticipated that marine mammals present in the vicinity of the Array marine mammal study area are familiarised to passing ships in the area.
  5. It is anticipated that the risk of collision at other CEA projects, such as the Proposed offshore export cable corridor(s) would be reduced through the adoption of factored-in measures similar to those for the Array, such as vessel codes of conduct as standard good practice for offshore wind developments. Therefore, even with a cumulative increase in vessel traffic, the type of vessels involved and transit routes is unlikely to impose a much greater risk to marine mammals than baseline levels.
  6. The cumulative impact is predicted to be of local spatial extent in the context of the geographic frame of reference, medium term duration, intermittent and, whilst the risk will only occur during vessel transits, the effect of collision on sensitive receptors is of medium to low reversibility (depending on the extent of injuries). It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described in section 10.11.2, paragraph 449 et seq. and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and not all collisions being fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the NSVMP, volume 4, appendix 24 and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Operation and maintenance phase
Magnitude of impact
  1. One Tier 1 project was identified with potential for cumulative effects associated with this impact within the 50 km buffer, in the regional marine mammal study area:
  • Proposed offshore export cable corridor(s) (construction and operation and maintenance phases).
  1. Vessel use during operation and maintenance phase of Array may lead to injury to marine mammals due to collision with vessels (including CTVs, SOVs, jack-up vessels, cable repair vessels, CSVs and DSVs). The types of vessels are similar to those presented for the maximum design scenario for the construction phase. An overview of the potential impacts due to vessel collision are described in paragraph 443 et seq. for the construction phase for the Array. The maximum scenario for the operation and maintenance phase of the Array is presented in Table 10.17   Open ▸ with up to 508 vessel round trips over the operational lifetime of the Array.
  2. As discussed in paragraph 592 for the Proposed offshore export cable corridor(s), there is no information in the public domain to determine if injury due to collision with vessels is scoped in, but it can be reasonably assumed it will be assessed in the EIA. If a project has not presented quantified information, then it is not appropriate for the Applicant to generate hypothetical numbers on the project’s behalf, however it can be assumed the impact assessment will be comparable or less than the Array.
  3. Given that vessel movements will be confined to the Array and Proposed offshore export cable corridor(s) and will follow existing shipping routes to/from port, the risk of collision to marine mammals is expected to be localised to within the boundaries of the respective projects. There is also a potential that the noise emissions from vessels will deter animals from the potential zone of impact.
  4. The operation and maintenance phase of the Array will temporally overlap with the operation and maintenance phase and decommissioning phase of the Proposed offshore export cable corridor(s). The operational lifetime of the Proposed offshore export cable corridor(s) is expected to run from 2038 to 2062, with decommissioning beginning in 2063. Vessel numbers for decommissioning are likely to be at worst, similar to those for construction phases, and it is expected animals will have some degree of habituation to vessel traffic that has been present throughout the operation and maintenance phases of CEA projects. Additionally, it can be expected that after decades of construction and maintenance activities taking place in the wider vicinity of the Array (within the regional marine mammal study area), marine mammals may have further habituated to higher vessel numbers. Therefore, the cumulative magnitude of the impact of the decommissioning phase of Proposed offshore export cable corridor(s) a result of collision with vessels, for all marine mammal receptors, are considered to be equivalent to and potentially lower than the maximum adverse effects assessed for the cumulative construction phase.
  5. The cumulative impact is predicted to be of local spatial extent, long term duration, intermittent and, whilst the risk will only occur during vessel transits, the effect of collision on sensitive receptors is of medium to low reversibility (depending on the extent of injuries). It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described in section 10.11.2 for the Array alone assessment, paragraph 449 et seq. and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and not all collisions being fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the NSVMP, volume 4, appendix 24 and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Decommissioning phase
Magnitude of impact
  1. One Tier 1 project was identified with potential for cumulative effects associated with this impact within the 50 km buffer, in the regional marine mammal study area:
  • Proposed offshore export cable corridor(s) (operation and maintenance phases).
  1. Vessel use during decommissioning phase of the Array may lead to injury to marine mammals due to collision with vessels. Vessels will be required for activities such as removal of foundation, cables and cable protection. Noise from vessels assumed to be as per vessel activity described for construction phase, with an overview of the potential impacts described in paragraph 443 et seq. for the construction phase.
  2. As discussed in paragraph 590 for the Proposed offshore export cable corridor(s), there is no information in the public domain to determine if injury due to collision with vessels is scoped in, but it can be reasonably assumed it will be assessed in the EIA.
  3. It is anticipated the Proposed offshore export cable corridor(s) will begin decommissioning before the Array and therefore there may be some overlap with the decommissioning phase of the Array, though decommissioning phases are a matter of years and much less than the operational phase of 35 years for the Array. As discussed in paraph 867, it is expected animals will have some degree of habituation to vessel traffic that has been present throughout the operation and maintenance phases of CEA projects. Additionally, it can be expected that after decades of construction and maintenance activities taking place in the wider vicinity of the Array (within the regional marine mammal study area), marine mammals may have further habituated to higher vessel numbers. Therefore, the cumulative magnitude of the impact of the decommissioning phase of the Array and Proposed offshore export cable corridor(s) a result of collision with vessels, for all marine mammal receptors, are considered to be equivalent to and potentially lower than the maximum adverse effects assessed for the cumulative construction phase.
  4. The cumulative impact is predicted to be of local spatial extent in the context of the geographic frame of reference, medium term duration, intermittent and, whilst the risk will only occur during vessel transits, the effect of collision on sensitive receptors is of medium to low reversibility (depending on the extent of injuries). It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described for the construction phase in paragraph 859 et seq. (with detail given in section 10.11.2, paragraph 449) and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and not all collisions being fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the NSVMP, volume 4, appendix 24 and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

                        Tier 2

Construction phase
Magnitude of impact
  1. There was one Tier 2 project identified within the 50 km buffer considered for potential for cumulative effects associated with this impact:
  • Morven BP-EnBW .
  1. The construction of the Array, together with construction phase of Tier 1 and Tier 2 projects ( Table 10.52   Open ▸ ) may lead to cumulative injury due to collision risk with vessels. Morven BP-EnBW is located within 50 km of the Array, all other Tier 2 Projects are located over 50 km away. The other Tier 2 Projects which are located >50 km from the Array are considered to be located at a distance great enough that cumulative impacts are highly unlikely.
  2. The Morven Offshore Scoping Report scopes in injury to marine mammals due to collision with vessels for the construction and decommissioning phase of the Morven Offshore Wind Project (Morven Offshore Wind Limited, 2023). Although there is no information on the numbers and types of vessels which will be associated with the construction phase of the Morven Offshore Wind Project, the types of vessels involved in construction activities at other offshore wind farms will be similar to those identified for the Array (such as those described in paragraph 864), and the number of vessel movements represents a slight increase in the risk of collision for marine mammals over the existing levels of vessel traffic.. As outlined in paragraph 856, the Array and respective projects are located in the area of relatively high vessel traffic, particularly cargo vessels (see paragraph 387 et seq.) and therefore it can be expected that marine mammals present in the area will demonstrate some degree of habituation to the presence of high number of vessels. Furthermore, the Array is located in proximity to oil and gas structures in the North Sea and as such the traffic of oil and gas vessels is substantial. Considering the baseline levels of vessel traffic, it can be anticipated that marine mammals present in the vicinity of the Array marine mammal study area are familiarised to passing ships in the area.
  3. The cumulative impact (injury due to collision risk with vessels) is predicted to be of local spatial extent in the context of the geographic frame of reference, medium term duration, intermittent and, whilst the risk will only occur during vessel transits, the effect of collision on sensitive receptors is of medium to low reversibility (depending on the extent of injuries). It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described for the construction phase in paragraph 859 et seq. (with detail given in section 10.11.2, paragraph 449) and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and not all collisions being fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the VMP and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Operation and maintenance phase
Magnitude of impact
  1. There was one Tier 2 project identified within the 50 km buffer considered for potential for cumulative effects associated with this impact:
  • Morven BP-EnBW
  1. The operation and maintenance phase of the Array, together with construction phase of Tier 1 and Tier 2 projects ( Table 10.52   Open ▸ ) may lead to cumulative injury due to collision risk with vessels. Morven BP-EnBW is located within 50 km of the Array, all other Tier 2 Projects are located over 50 km away. The other Tier 2 Projects which are located >50 km from the Array are considered to be located at a distance great enough that cumulative impacts are highly unlikely.
  2. There is the potential for the operation and maintenance phase of Morven BP-EnBW to overlap with the operation and maintenance phase of the Array. It should be noted that the Morven Offshore Scoping Report scoped out injury due to collision risk with vessels during the operation and maintenance phase on the basis that operation and maintenance vessels will transit slowly through the Morven Array, and the Morven Array will adhere to the Scottish Marine Wildlife Watching Code. This approach was discussed and confirmed by NatureScot via the Morven BP-EnBW Scoping Workshop.
  3. As described in paragraph 786, maintenance of cables or turbines typically involves considerably smaller numbers of vessels and round trips compared to construction. Considering the vessel activity within the North Sea, it is anticipated that these will not add substantially to the number of vessels present during the operation and maintenance phases of the Array, Tier 1 and Tier 2 projects and that the potential for cumulative effects is unlikely.
  4. It should also be considered that during the operation and maintenance phase of the Array some of the Tier 2 projects may be decommissioned. There may be an increase in vessel numbers associated with the decommissioning phases of the Tier 2 projects outlined. However, as outlined in paragraph 839, considering the vessel activity within the North Sea, it is anticipated that these will not add substantially to the number of vessels present during the operation and maintenance phases of the Array.
  5. The cumulative impact (injury due to collision risk with vessels) is predicted to be of local spatial extent in the context of the geographic frame of reference, long term duration, intermittent and is of medium to low reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described for the construction phase in paragraph 859 et seq. (with detail given in section 10.11.2, paragraph 449) and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and not all collisions being fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the NSVMP, volume 4, appendix 24 and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Decommissioning phase
Magnitude of impact
  1. There was one Tier 2 project identified within the 50 km buffer considered for potential for cumulative effects associated with this impact:
  • Morven BP-EnBW.
  1. Based on a 35-year operational lifetime, and the commencement of operation and maintenance phase in 2038, decommissioning at Morven is likely to occur from 2073 and potential overlap with decommissioning phase at the Array. Cumulative effects from underwater noise generated during vessel use and other noise producing activities are not anticipated.
  2. The cumulative impact (injury due to collision risk with vessels) is predicted to be of local extent in the context of the geographic frame of reference, medium-term duration, intermittent and is of medium to low reversibility (depending on the extent of injuries). It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described for the construction phase in paragraph 859 et seq. (with detail given in section 10.11.2, paragraph 449) and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and the argument that not all collisions are fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the NSVMP, volume 4, appendix 24 and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

                        Tier 3

Construction phase
Magnitude of impact
  1. There were three Tier 3 projects identified with potential for cumulative effects associated with this impact:
  • Bellrock Offshore Wind Farm;
  • Bowdun Offshore Wind Farm;
  • Campion Offshore Wind Farm;
  • Morven BP-EnBW Offshore Export Cable Corridor.
  1. Tier 3 projects are in a pre-application phase and no EIA Scoping Report or EIA Report is available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
  2. Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm, Campion Offshore Wind Farm and Morven BP-EnBW Offshore Export Cable Corridor are all located within 50 km of the Array, all other Tier 3 projects are located over 50 km away. The other Tier 3 projects which are located >50 km from the Array are considered to be located at a distance great enough that cumulative impacts are highly unlikely.
  3. There is no information in the public domain on potential numbers of vessels associated with the construction phase of Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm, Campion Offshore Wind Farm and Morven BP-EnBW Offshore Export Cable Corridor, and construction timelines are unknown. If any overlap of the construction phases were to occur, the uplift in vessels would be primarily restricted to within the relevant discrete project footprints, with the implementation of standard industry measures such as PAM and MMOs2 the potential for cumulative effects is very low. The operation and maintenance phase of offshore wind projects typically involves considerably fewer vessels and round trips compared to construction. Therefore, it is anticipated that these will not add substantially to the number of vessels present during the construction of the Array and that the potential for cumulative effects is unlikely.
  4. The cumulative impact (injury due to collision risk with vessels) is predicted to be of local to regional spatial extent in the context of the geographic frame of reference, medium-term duration, intermittent and the effect of behavioural disturbance is of high reversibility (with animals returning to baseline levels soon after they moved from the impact zone). It is predicted that the impact will affect the receptor directly. Whilst there may be effects at an individual level, these are not predicted to be at a scale that would lead to any population-level effects. The magnitude was therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described in paragraph 859 et seq. (with detail given in section 10.11.2, paragraph 449) for construction and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and not all collisions being fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the NSVMP, volume 4, appendix 24 and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

 

Operation and maintenance phase
Magnitude of impact
  1. There were three Tier 3 projects identified within the 50 km buffer considered for potential for cumulative effects associated with this impact:
  • Bellrock Offshore Wind Farm;
  • Bowdun Offshore Wind Farm;
  • Campion Offshore Wind Farm; and
  • Morven BP-EnBW Offshore Export Cable Corridor.
  1. Tier 3 projects are in a pre-application phase and no EIA Scoping Report or EIA Report is available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
  2. As described in paragraph 786, maintenance of cables or turbines typically involves considerably smaller numbers of vessels and round trips compared to construction. Considering the vessel activity within the North Sea, it is anticipated that these will not add substantially to the number of vessels present during the operation and maintenance phases of the Array, Tier 1 and Tier 2 projects and that the potential for cumulative effects is unlikely.
  3. It should also be considered that during the operation and maintenance phase of the Array some of the Tier 3 projects may be decommissioned. There may be an increase in vessel numbers associated with the decommissioning phases of the Tier 3 projects outlined above. However, as outlined in paragraph 839, considering the vessel activity within the North Sea, it is anticipated that these will not add substantially to the number of vessels present during the operation and maintenance phases of the Array.
  4. The cumulative impact (injury due to collision risk with vessels) is predicted to be of local to regional spatial extent, long term duration, intermittent and the effect of behavioural disturbance is of high reversibility (with animals returning to baseline levels soon after they moved from the impact zone). It is predicted that the impact will affect the receptor directly. Whilst there may be effects at an individual level, these are not predicted to be at a scale that would lead to any population-level effects. The magnitude was therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described in paragraph 859 et seq. (with detail given in section 10.11.2, paragraph 449) for construction and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and not all collisions being fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the NSVMP, volume 4, appendix 24 and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Decommissioning phase
Magnitude of impact
  1. There were three Tier 3 projects identified within the 50 km buffer considered for potential for cumulative effects associated with this impact:
  • Bellrock Offshore Wind Farm;
  • Bowdun Offshore Wind Farm;
  • Campion Offshore Wind Farm; and
  • Morven BP-EnBW Offshore Export Cable Corridor.
  1. Tier 3 projects are in a pre-application phase and no EIA Scoping Report or EIA Report is available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
  2. On the basis of a 35 year operational lifetime, decommissioning will not occur at the Array until 2074. There is unlikely to be a temporal overlap between Tier 3 projects and decommissioning at the Array. Cumulative effects from underwater noise generated during vessel use and other noise producing activities are not anticipated.
  3. The cumulative impact (injury due to collision risk with vessels) is predicted to be of local to regional spatial extent, medium-term duration, intermittent and the effect of behavioural disturbance is of high reversibility (with animals returning to baseline levels soon after they moved from the impact zone). It is predicted that the impact will affect the receptor directly. Whilst there may be effects at an individual level, these are not predicted to be at a scale that would lead to any population-level effects. The magnitude was therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to collision risk is as described in for the construction phase in paragraph 859 et seq. (with detail given in section 10.11.2, paragraph 449) and is not repeated here.
  2. All marine mammals are deemed to have some resilience (largely due to avoidance behaviour and not all collisions being fatal), medium recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low (particularly with the adoption of the NSVMP, volume 4, appendix 24 and similar measures for other projects) and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

Effects On Marine Mammals Due To EMFs From Subsea Electrical Cabling In The Water Column

                        Tier 1

Operation and maintenance phase only
Magnitude of impact
  1. One Tier 1 project was identified with potential for cumulative effects associated with this impact within the 10 km buffer, in the regional marine mammal study area:
  • Proposed offshore export cable corridor(s) (construction and operation and maintenance phases).
  1. As discussed in paragraph 590, there is no information in the public domain to determine if effects on marine mammals due to EMFs is scoped in for the Proposed offshore export cable corridor(s), but as a precautionary approach we have included it in the assessment given the potential effects of EMF from a cable project. However, given that the Proposed offshore export cable corridor(s) is a HVDC subsea power cable, they will not include dynamic cabling, and will likely be entirely buried and protected where burial is not practicable. Cable burial and cable protection are common industry practice measures, which can reduce EMF levels in the benthic environment (Chapman et al., 2023, CSA Ocean Sciences Inc and Exponent, 2019, Gill et al., 2005, Gill et al., 2009, Hervé, 2021) and it is unlikely marine mammal receptors will spend any significant amount of time near the seabed (given their highly mobile nature, pelagic lifestyle and need to surface for air periodically) which would lead to any substantial cumulative effects beyond those for the Array alone.
  2. As presented in paragraphs 469 et seq., EMF levels in the vicinity of subsea cables are influenced by a variety of design and installation factors, including distance between cables, cable sheathing, number of conductors, and internal cable configuration. Therefore, the cumulative magnitude of impact with the Tier 1 projects is likely to be highly localised to within metres to tens of metres from cables.
  3. As discussed in paragraph 472, significant knowledge gaps around the estimates of cumulative EMF exist and the magnitude of repeated exposure through time and space (Ocean Science Consulting Ltd., 2022). Therefore, at this stage it is difficult to quantify the exact effects of EMF on marine mammals but it is anticipated the cumulative effect will not lead to any substantial further disturbance to marine mammals due to the factors described above.
  4. The cumulative impact is predicted to be of local spatial extent, long term duration, continuous and high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to EMF is as described for the Array, with detail given in section 10.11.2, paragraph 476 et seq.) and is not repeated here.
  2. All receptors, except humpback whale, are deemed to be of high resilience, high recoverability and adaptability and international value. The sensitivity of these receptors is therefore, considered to be low. Humpback whale is deemed to be of medium resilience and adaptability and high recoverability. The sensitivity of humpback whale is therefore, considered to be medium.
Significance of effect
  1. Overall, for all marine mammal species, the magnitude of the impact is deemed to be low and the sensitivity is considered to be low for all species except humpback whale, which is assessed as medium. Due to the uncertainty associated with the magnitude, the effect for all species is assessed precautionarily as being of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.