Moray Firth SAC
Bottlenose dolphin

                        Tier 1

  1. As presented in paragraphs 769 et seq., there were three Tier 1 projects identified with potential for in-combination effects, and two projects (Berwick Bank and Hornsea Project Three) were screened in and assessed as part of the Tier 1 assessment. Bottlenose dolphin was not scoped in as a key species for Hornsea Project Three (Ørsted, 2018a), therefore this project is excluded from the Tier 1 assessment. However, bottlenose dolphin was considered in Berwick Bank Wind Farm (SSE Renewables, 2022c) and therefore can be included in the in-combination assessment for Tier 1.
  2. Berwick Bank Wind Farm (SSE Renewables, 2022c) used a dual metric approach to estimate bottlenose dolphin disturbed. The EIA used noise contours overlaid with 2 m to 20 m depth contours and calculated numbers of animals in those areas, using a density of 0.197 animals per km2 from Peterhead to Farne Islands and 0.294 animals per km2 for the outer Firth of Tay (where the density is higher). Furthermore, the number of bottlenose dolphins potentially disturbed during piling in offshore areas was calculated using densities from SCANS III Block R data (0.0298 animals per km2). Up to five bottlenose dolphins are predicted to have the potential to experience disturbance from concurrent piling in coastal waters (2.25% of the Coastal East Scotland MU population) based upon 1% constant conversion factor and maximum hammer energy of 4,000 kJ (SSE Renewables, 2022c) ( Table 6.65   Open ▸ ). Coastal bottlenose dolphin could also be potentially disturbed during single piling at a wind turbine or an OSPs/Offshore convertor station platform, with up to four (1.49% of the Coastal East Scotland MU population) animals affected (SSE Renewables, 2022c) ( Table 6.65   Open ▸ ).
  3. Potential effects on the offshore bottlenose dolphin population were also assessed in the EIA for Berwick Bank Wind Farm. During concurrent piling at maximum 4,000 kJ hammer energy, up to 102 individuals occurring in offshore waters have the potential to experience disturbance (5.29% of SCANS III Block R). For the single piling scenario, up to 64 individuals have the potential to experience disturbance offshore, which equates to 3.29% of the SCANS III Block R estimated abundance. The EIA did state the densities were considered to be conservative as these are based on highly precautionary coastal and offshore density estimates. Population modelling for bottlenose dolphin against the MU population showed that the median of the ratio of the impacted population to the unimpacted population was a ratio of 1 at 25 years and there was no potential for a long-term effect on this species. The magnitude for Berwick Bank Wind Farm, for behavioural impacts from piling, was considered to be low.
  4. Within the RIAA for Berwick Bank Wind Farm, there was no potential for overlap between the 140 dB and 160 dB (rms) noise disturbance contours and the Moray Firth SAC (SSE Renewables, 2022e). Up to five animals from the Moray Firth SAC population were predicted to experience mild disturbance but this is unlikely to lead to barrier effects as animals are unlikely to be excluded from the coastal areas. Given that modelled noise contours in Berwick Bank Wind Farm did not extend to the Moray Firth SAC and animals are expected to experience only mild behavioural disturbance within the Coastal East Scotland MU, behavioural disturbance is unlikely to alter the distribution of bottlenose dolphin such that recovery cannot be expected, or effects can be considered long term (SSE Renewables, 2022e).
  5. There is potential overlap of one year of piling at the Array with Berwick Bank Wind Farm, which may lead to in-combination effects. Up to ten animals (in the Coastal East Scotland MU) may be disturbed if concurrent piling of wind turbines at Berwick Bank Wind Farm and concurrent piling at the Array occur simultaneously. However, Berwick Bank Wind Farm is located 56.84 km south-east from the Array, and the likelihood of in-combination effects with projects located at large distances is considered to be reduced.
Table 6.65:
Bottlenose Dolphin In-Combination Assessment – Numbers of Animals Predicted to be Disturbed as a Result of Underwater Noise During Piling for Tier 1 Projects

Table 6.65 Bottlenose Dolphin In-Combination Assessment – Numbers of Animals Predicted to be Disturbed as a Result of Underwater Noise During Piling for Tier 1 Projects

 

  1. Population modelling (see volume 3, appendix 10.3 of the Array EIA Report) considered Berwick Bank Wind Farm alongside the Array (a quantitative assessment for Proposed offshore export cable corridor(s) is not available and Hornsea Three did not assess bottlenose dolphin/it lies outside of the Coastal East Scotland MU), with respective numbers of animals potentially impacted against the MU population. For bottlenose dolphin, the Coastal East Scotland MU was used as the relevant reference population for in-combination population modelling. Given the importance of the Moray Firth SAC for bottlenose dolphin in this area, the sensitivity of this population and its known ranging behaviour further south towards St Andrews Bay and the Tay Estuary, and inshore in north-east English waters, it is important to capture the potential impact on this important coastal ecotype which may experience potential barrier effects. Whilst there is an abundance estimate for the Greater North Sea MU (2,022 animals (IAMMWG, 2023)) this large MU extends the entire length of the east coast of the UK and east to Scandinavia, so apportioning numbers of the offshore ecotype to the east coast of Scotland is not possible. It is also unlikely that the Array will create significant barrier effects for this offshore ecotype. Therefore, the in-combination modelling assessment for the Array used the Coastal East Scotland MU as the relevant reference population.
  2. Results of the iPCoD modelling for bottlenose dolphin undertaken for the EIA showed that the median of the ratio of impacted population to unimpacted population approaches had a ratio of 1 at all modelled time points, with ten fewer animals in the impacted population at 25 years after the start of piling, compared to the impacted population. Therefore, it was not considered that there is potential for a long-term effect on this species as a result of piling at the Array and respective Tier 1 projects within the Array EIA Report (volume 2, chapter 10). Furthermore, given the population modelling used the Coastal East Scotland MU, and the site boundary sits outside of this MU (by approximately 50 km west from the site boundary at the closest point), it is considered further unlikely to have long-term effects on the offshore ecotype.

                        Tier 2

  1. The Tier 2 assessment, presented in paragraphs 781 et seq., concluded that in-combination effects as a result of piling in the construction phase are unlikely to occur. This is largely due to the distance between many Tier 2 projects and the site boundary (i.e. often over hundreds of kilometres). Further, piling at the Tier 2 projects will be intermittent, and the effects of behavioural disturbance are reversible. Based on this, it is concluded that piling in-combination at the Array and the Tier 2 projects will not have an adverse effect on the integrity of bottlenose dolphin feature of this SAC.

                        Tier 3

  1. The Tier 3 assessment, presented in paragraphs 792 et seq., highlighted that it was not possible to undertake any quantitative in-combination assessment for the 11 Tier 3 projects identified for this impact. This was due to the lack of publicly available information surrounding piling parameters and lack of information in general about INTOG projects. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 3 projects.
  2. There is no publicly available piling parameters or published assessments for Tier 3 projects (which are at pre-scoping stage), however given the phase of development, temporal overlap with the Array may be limited. Furthermore, given the maximum injury ranges for bottlenose dolphin associated with piling from the Array (maximum PTS range of 171 m modelled for the Array alone), there is low likelihood of any spatial overlap of ranges between the Array and the Tier 3 projects. For example, the closest Tier 3 projects are the Morven Offshore Export Cable Corridor (5.5 km away) and Bellrock Offshore Wind Farm (8.67 km away), which both far exceed the maximum PTS range for bottlenose dolphin. Further, the potential for PTS is reduced through the application of designed-in measures, and animals are expected to be able to flee the injury zone due to ADD activation prior to commencement of soft starts ( Table 6.11   Open ▸ ). Therefore there is limited potential for an in-combination impact associated with the Tier 3 projects, and each project will likely implement their own mitigation to limit injury and disturbance as per the JNCC (2010c) guidelines, thus further reducing the potential for in-combination effects associated with piling.
  3. Based on this, it is concluded that piling in-combination at the Array and the Tier 2 projects will not have an adverse effect on the integrity of bottlenose dolphin feature of this SAC.

                        Conclusion

  1. Adverse effects on the qualifying Annex II marine mammal features of the Moray Firth SAC which undermine the conservation objectives of the SAC will not occur as a result of in-combination underwater noise generated during piling in the construction phase. Potential effects from this activity on the relevant conservation objectives (as presented in section 6.2.3) are discussed in turn below in Table 6.66   Open ▸ .

 

Table 6.66:
Conclusions Against the Conservation Objectives of the Moray Firth SAC from Underwater Noise Generated During Piling in the Construction Phase of the Array In-Combination with other Plans and Projects

Table 6.66: Conclusions Against the Conservation Objectives of the Moray Firth SAC from Underwater Noise Generated During Piling in the Construction Phase of the Array In-Combination with other Plans and Projects

 

  1. It can be concluded, beyond reasonable scientific doubt, that there is no risk of an adverse effect on the integrity of the Moray Firth SAC as a result of underwater noise generated during piling with respect to the construction phases of the Array in-combination with other plans and projects.

6.4.3. Underwater Noise Generated during UXO Clearance

  1. The LSE2 assessment during the HRA Stage One process identified that LSE2 could not be ruled out for underwater noise generated during UXO clearance in the construction phase of the Array in-combination with other plans and projects. This relates to the following sites and relevant Annex II marine mammal features:
  • Berwickshire and North Northumberland Coast SAC;

–           grey seal.

  • Southern North Sea SAC; and

–           harbour porpoise.

  • Moray Firth SAC;

–           bottlenose dolphin.

  1. The MDS considered for this in-combination assessment is shown in Table 6.67   Open ▸ . The designed in measures are presented in Table 6.19   Open ▸ for the assessment of the Array alone.

 

Table 6.67:
MDS Considered for the Assessment of Potential Impacts to Annex II Marine Mammals due to Underwater Noise Generated During UXO Clearance in the Construction Phase of the Array In-Combination with other Plans and Projects

 Table 6.67: MDS Considered for the Assessment of Potential Impacts to Annex II Marine Mammals due to Underwater Noise Generated During UXO Clearance in the Construction Phase of the Array In-Combination with other Plans and Projects

 

                        In-combination assessment

  1. There is the potential for in-combination impacts from underwater noise from UXO clearance in the construction phase of the Array and other plans and projects. For the purposes of this assessment, this potential impact has been assessed using the tiered approach outlined in section 4.6. The plans and projects screened into the in-combination assessment for this potential impact and their respective tiers are outlined in Table 6.67   Open ▸ .
                        Tier 1
  1. There were two Tier 1 projects within the 100 km buffer identified with potential for in-combination effects associated with this impact:
  • the construction phases of the Proposed offshore export cable corridor(s); and
  • the construction phases of Berwick Bank Wind Farm ( Table 6.67   Open ▸ ).
  1. Potential impacts of underwater noise from UXO detonations on marine mammals include mortality, physical injury or auditory injury. The risk of injury in terms of PTS to marine mammal receptors as a result of underwater noise during UXO clearance would be expected to be localised to the vicinity around the boundaries of the respective projects. It also is anticipated that standard offshore wind industry mitigation methods (which include visual and acoustic monitoring of marine mammals as standard and additional mitigation in form of ADDs and/or soft start charges) will be applied based on UXO specific risk assessment and if any residual risk of injury remains it will be mitigated further post-consent, thereby reducing the severity of the potential impact with respect to auditory injury occurring in marine mammals. However, the potential for a residual risk of injury was investigated based on the UXO clearance technique and mitigation proposed for each project.
  2. As previously presented for the Array alone in paragraph 560 et seq. (which uses TTS as a proxy for disturbance), the duration of effect for each UXO detonation is less than one second and behavioural effects are therefore considered to be negligible in this context.
  3. Projects screened in for this in-combination assessment are expected to involve similar construction activities to those described for the Array alone, including UXO clearance activities. It is anticipated that, for all projects, impacts associated with these activities will also require additional assessment under EPS licensing.
  4. Berwick Bank Wind Farm based their assessment on 14 UXOs requiring clearance (SSE Renewables, 2022c) ( Table 6.68   Open ▸ ) (up to 70 UXOs are likely to be found within the Berwick Bank Array Area and the Berwick Bank Proposed offshore export cable corridor(s), however, only 14 of these will require clearance based upon experience at Seagreen Wind Energy Ltd (2021)) and noise modelling was undertaken for UXO clearance (both low order and high order detonation) using the methodology described in Soloway et al. (2014). The EIA did state the precise details and locations of potential UXOs was unknown at the time of assessment. For the purposes of the UXO assessment, it was assumed that the maximum design scenario is UXO size up to 300 kg, and the maximum frequency would be up to two detonations within 24 hours. Berwick Bank Wind Farm stated low order techniques will be applied as the intended methodology for clearance of UXO (in which case in-combination effects would be further reduced) however, highlighted there is a small risk that a low order clearance could result in high order detonation of UXO, and some UXOs may need to be cleared with high order methods and therefore whilst both low and high order clearance was assessed, the MDS was based upon high order clearance (300 kg).

 

Table 6.68:
UXO Clearance Parameters for the Array and Berwick Bank Wind Farm

Table 6.68 UXO Clearance Parameters for the Array and Berwick Bank Wind Farm

Auditory injury (PTS)
  1. For a given marine mammal hearing group, exceedance of the threshold for the onset of PTS may result in a permanent hearing loss which in turn could inhibit ecological functioning, such as communication, foraging, navigation, and predator avoidance. The inability to continue with these important activities could eventually lead to a decline in vital rates of an individual, including growth, reproduction and subsequently survival. Depending on the type of detonation and size of UXO, UXO clearance activities may have residual effects in respect to marine mammals and PTS injury. In November 2021, the UK Government published a joint interim statement advising to use low noise alternatives to high order detonations where possible and it is anticipated that future developments will follow this guidance (JNCC, 2021c, UK Government et al., 2022).
  2. For the Array alone, with measures adopted as part of the Array applied there was predicted to be a small residual effect of PTS based on accidental high order detonation of UXOs. Within the EIA Report (volume 2, chapter 10), the residual magnitude for all species, except for harbour porpoise, was determined to be low. For harbour porpoise, it is expected that small, nominal number of animals could be exposed to PTS threshold ( Table 6.69   Open ▸ ). Given that details about the UXO clearance technique to be used and charge sizes will not be available until after the consent is granted and are currently derived from desk-based study used to develop an MDS for this impact (Ordtek (2022)), it is not appropriate to quantify the effects of UXO detonations which are subject to change, and therefore summing the residual number of animals at multiple projects (prior to secondary mitigation) is not presented within this in-combination assessment. At a later stage, when details about the exact UXO sizes and specific clearance techniques to be used become available following detailed site investigation surveys, it will be possible to tailor the secondary mitigation to specific UXO sizes and species in order to reduce the risk of injury. Therefore, prior to the commencement of UXO clearance works, an EPS licence will be sought as required based on the further detailed information on UXOs available at the time, following site investigation surveys, and with the application of appropriate secondary mitigation measures as a part of the final MMMP (with an outline MMMP given in volume 4, appendix 22 of the Array EIA Report). It is therefore anticipated that following the application of secondary mitigation, the residual potential for potential impact will be reduced to low, and no adverse effect on the integrity of the SACs is predicted.
  3. The assessment for Berwick Bank Offshore Wind Farm determined harbour porpoise were likely to be the most sensitive species to potential injury from high order UXO clearance. The EIA found that the maximum injury (PTS) range estimated for harbour porpoise using the SPLpk metric is 10,630 m for the high order detonation of charge size of 300 kg. Conservatively, the number of harbour porpoise that could be potentially injured during each high order detonation of UXO was up to 293 individuals (0.08% of the North Sea MU population and 0.76% of SCANS III Block R). Using the SELcum metric, the predicted number of animals potentially affected was 38 animals. In the assessment, up to 16 grey seals had the potential to be injured during each high order detonation of the UXO (0.04% of the East Scotland plus Northeast England SMUs). Less than one bottlenose dolphin had the potential to be injured (SSE Renewables, 2022c) ( Table 6.69   Open ▸ ).
  4. The Berwick Bank Wind Farm EIA (SSE Renewables, 2022c) detailed designed in measures will be adopted as part of a MMMP to reduce the potential of experiencing injury. However, the mitigation zones required of 10 km are considerably larger than the standard 1,000 m mitigation zone recommended for UXO clearance (JNCC, 2010a). Visual surveys note that there is often a significant decline in detection rate with increasing sea state (Embling et al., 2010, Leaper et al., 2015). Therefore, the EIA details additional mitigation will be applied in the form of soft start charges and ADDs to reduce residual risk of injury. The assessment therefore determined that with the application of secondary mitigation measures (upon receipt of more detail regarding size and number of UXO post-consent as part of the EPS licence supporting information for UXO clearance), the magnitude of this potential impact will be reduced to low. Therefore, Berwick Bank EIA assessed the residual effect of auditory injury as minor adverse, with the residual magnitude as low following application of secondary measures (the unmitigated magnitude was medium based upon high order UXO clearance).
Table 6.69:
Number of Animals with the Potential to Experience PTS During UXO Clearance at Tier 1 Projects Prior to any Mitigation, and Residual Magnitude assessed in the EIA

Table 6.69: Number of Animals with the Potential to Experience PTS During UXO Clearance at Tier 1 Projects Prior to any Mitigation, and Residual Magnitude assessed in the EIA

 

  1. Although development of the Proposed offshore export cable corridor(s) will also be undertaken by the Applicant, route optioneering work is ongoing and so UXO surveys have not yet been completed. Therefore, there is currently no information by which to determine if UXO is scoped in or out of the impact assessment. Furthermore, 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 any sort of quantitative assessment of UXO clearance. It can be reasonably assumed, however, that the extent of the impacts for the Proposed offshore export cable corridor(s) are expected to be of a similar extent than those represented by the MDS for the Array alone, since 698 kg represents a large munition size for the North Sea (section 6.3.2).
  2. UXO clearance at each of these Tier 1 projects will occur as a discrete stage within the overall construction phase and therefore will not coincide continuously over the duration of temporal overlap. Furthermore, each clearance event results in a very short duration of sound emission (seconds) so the impact will be short in duration and therefore the overlap is unlikely. For example, whilst there is uncertainty in the final grid connection design and location details of the Proposed offshore export cable corridor(s), the Proposed offshore export cable corridor(s) is predicted to begin construction one year prior to the Array construction phase ( Table 6.57   Open ▸ ), and therefore there will be no overlap in UXO clearance.
  3. Given that the risk of injury will be reduced by the appropriate standard industry measures at respective projects to reduce the risk of PTS to marine mammals, the in-combination risk of injury is expected to be reduced further. At the Array with designed-in measures applied ( Table 6.19   Open ▸ ), it is anticipated that all species except harbour porpoise would be deterred from the injury zone and therefore the likelihood of PTS and population-level effects would be unlikely. However, following the application of secondary mitigation as described in paragraph 580 et seq. and more detail regarding size and number of UXO, the risk of in-combination impact is considered to be low, as a reduction in potential impact to a non-significant level will reduce the Array’s contribution to any in-combination impact on harbour porpoise in the North Sea MU (i.e., the in-combination assessment takes into account the Array alone commitments to reducing the potential for significant auditory injury to a non-significant level). Therefore, with the residual magnitude for harbour porpoise for both the Array alone and Berwick Bank Wind Farm as low in their respective EIA Reports, and the residual magnitude for other marine mammal receptors as negligible, it is anticipated that the in-combination impact will be reduced to a non-significant level for all species assessed in this Part of the RIAA.
Behavioural disturbance (TTS as proxy)
  1. For this impact, TTS is applied as a proxy for strong disturbance (although noting that TTS onset could potentially result in a temporary loss in hearing). Whilst some behaviours (e.g. feeding, communication, socialisation) could be inhibited in the short term due to disruptions in ecological function (including a temporary hearing shift), these are reversible and therefore not considered likely to lead to any long-term effects on the individual. As discussed in paragraph 560, the duration of effect for each UXO detonation is less than one second and therefore behavioural effects are considered to be negligible in this context.
  2. For Berwick Bank Wind Fam, the maximum range across which animals have the potential to experience disturbance (using TTS as a proxy) due to high order detonation of a 300 kg charge (as the MDS) was assessed for harbour porpoise as approximately 19 km. The disturbance ranges for bottlenose dolphin and grey seal are relatively small with a maximum of approximately 1 km and 6 km, respectively (SSE Renewables, 2022c).
  3. Production of underwater noise during detonation of UXOs as a part of the in-combination projects as well as the Array have the potential to cause disturbance (TTS) in marine mammal receptors, however, this effect will be very short-lived (during detonation only) and reversible. A spatial MDS would occur where UXO clearance activities occur concurrently at the respective projects considered in the in-combination assessment. Sequential UXO clearance at respective projects could lead to a longer duration of effect. However, as described in paragraph 851, each clearance event results in a very short duration of noise emission (seconds) so the potential impact will be short in duration and therefore the overlap is unlikely, particularly given the construction phases of the Tier 1 projects are likely to be completed several years before the construction phase of the Array begins (i.e. due to safety reasons, UXO clearance activities takes place before other construction activities commence (JNCC, 2023a)).
  4. Since each clearance event results in no more than a one second ensonification event and since animals are anticipated to recover quickly, the potential for in-combination effects with respect to disturbance is considered to be very limited. Furthermore, Berwick Bank Wind Farm lies over ~50 km away from the Array and therefore (given the maximum effect range was modelled as 19 km for harbour porpoise in the Berwick Bank EIA) it is unlikely to lead to in-combination behavioural effects.
  5. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 1 projects. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 1 projects will not have an adverse effect on the integrity of the marine mammal features of the SACs assessed in this Part of the RIAA.
                        Tier 2
  1. There were four Tier 2 projects identified in the 100 km buffer of the Array with potential for in-combination effects associated with this impact:
  • Cenos Offshore Wind Farm;
  • Morven Offshore Wind Farm;
  • Muir Mhor Offshore Wind Farm; and
  • Salamander Offshore Wind Farm ( Table 6.67   Open ▸ ).
  1. The Cenos Offshore Wind Farm (Flotation Energy, 2023) included removal of UXO in construction impacts and stated if UXO is found, an underwater noise assessment specific to the UXO (the current presence and and characteristics of UXO cannot be predicted) found will be completed to inform mitigation and EPS application. The dates of construction at Cenos Offshore Wind Farm are unknown, but potential overlap is unlikely given the short timescales of UXO clearance, and in combination with the distance from the Array (approximately 91.70 km) means that there is minimal spatial overlap from PTS and behavioural disturbance ranges and therefore potential for in-combiantion effects are unlikely.
  2. The Morven Offshore Wind Farm scoped in injury and disturbance from UXO clearance in its Scoping Report (Morven Offshore Wind Limited, 2023). The Scoping Report detailed that a range of UXO sizes and clearance methodologies will be explored to develop the MDS (e.g. largest and most likely size/type of UXO, number of possible UXOs requiring clearance, high order vs low order/low yield clearance methodologies). The Morven construction phase has been assumed from 2031 to 2038, and therefore overlaps fully with that of the Array ( Table 6.57   Open ▸ ).
  3. The EIA Scoping Report for Muir Mhor Offshore Wind Farm (Fred Olsen Seawind et al., 2023) proposed that noise related impacts associated with construction activities resulting in auditory injury (i.e. PTS) and behavioural disturbance are scoped into the EIA, and included UXO clearance. The impact assessment of the risk of auditory injury scoped in as a result of UXO clearance operations will include an assessment for both high order detonations and low order detonations, whilst aligning with recent recommendations and position statements on UXO clearance for similar offshore wind farm developments in the area. Construction at Muir Mhor Offshore Wind Farm is planned from 2027 to 2030, and any UXO clearance is likely to be undertaken prior to the construction phase, therefore it is unlikely there will be overlap of UXO clearance with the Array as it will be carried out prior to the Array construction phase. This, along with the distance from the site boundary (approximately 51.38 km) means that there is minimal spatial overlap from PTS and behavioural disturbance ranges and therefore potential for in-combination effects are unlikely.
  4. The EIA Scoping Report for Salamander Offshore Wind Farm (Simply Blue Energy (Scotland) Limited, 2023) stated while UXO clearance will be subject to a separate Marine Licence application, an indicative assessment of the potential for noise impacts to marine mammals from UXO clearance during the construction phase will be included in the EIA, and therefore scoped in UXO clearance. The underwater noise assessment will likely include a quantitative assessment of the risk of injury and disturbance (using TTS-onset as a proxy) to all species scoped-in as a result of UXO clearance operations, based on indicative example UXO sizes supported by noise propagation modelling. The Salamander Offshore Wind Farm Scoping Report states the MMMP will be implemented for UXO clearance if needed. The dates of construction at Salamander Offshore Wind Farm are unknown, but potential overlap is unlikely given the short timescales of UXO clearance, and in combination with the distance from the Array (approximately 79.49 km) means potential for in-combination effects are unlikely.
  5. It is expected that given that the risk of injury will be reduced by standard industry measures (including visual and acoustic monitoring) at respective projects, the in-combination risk of injury is expected to be reduced further. As discussed in paragraph 852 for the Tier 1 assessment, the in-combination assessment considers the Array’s commitments to reducing any potential significant auditory injury to a non-significant level by implementation of designed in measures described in Table 6.19   Open ▸ (i.e. soft starts to UXO clearance, deployment of ADDs up to 30 mins prior to commencement of UXO clearance, application of low-order deflagration of UXO (where practicable) and implementation of a MMMP) and secondary mitigation measures discussed in paragraphs 580 et seq. (i.e. deployment of ADDs beyond 30 mins for prior to UXO clearance).
  6. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 2 projects. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 2 projects will not have an adverse effect on the integrity of the marine mammal features of the SACs assessed in this Part of the RIAA.
                        Tier 3
  1. There were seven Tier 3 projects identified in the 100 km buffer with potential for in-combination effects associated with this impact:
  • Bellrock Offshore Wind Farm;
  • Bowdun Offshore Wind Farm;
  • Campion Offshore Wind Farm;
  • Flora Floating Wind Farm;
  • Aspen Offshore Wind Farm;
  • Cedar Offshore Wind Farm; and
  • Morven Offshore Export Cable Corridor(s) ( Table 6.67   Open ▸ ).
  1. The construction of the Array, together with construction phase of Tier 1, Tier 2 and Tier 3 projects may lead to in-combination injury and disturbance to marine mammals from underwater noise generated during UXO clearance.
  2. As described in paragraph 795, the data in relation to Tier 3 projects available at the time of writing is limited, this is particularly the case for INTOG projects which as a new concept very little is known about the scale of the potential environmental impacts associated with these projects. Tier 3 projects were screened in precautionarily based on their location within 100 km of the site boundary within the regional marine mammal study area (noting this is a highly precautionary screening area for UXO clearance), though there is limited/no information on the construction/operation dates or project design with regards to UXO clearance. It should be acknowledged that there is a potential for UXO clearance activities to be taking place at these Tier 3 projects, and therefore in-combination effects cannot be discounted. However, at this point in time, is not possible to undertake a detailed quantitative assessment for potential in-combination impacts as a result of underwater noise generated during UXO clearance from the Array and other Tier 3 projects. There is no publicly available UXO clearance parameters or published assessments for Tier 3 projects (which are at pre-scoping stage), however given the phase of development there is likely to be no temporal overlap with the Array. Furthermore, given the maximum un-mitigated UXO ranges from the Array (maximum PTS range of 14.5 km, 26.7 km for TTS) there is low likelihood of any spatial overlap of ranges between the Array and Campion, Flora Floating Wind Farm, Aspen and Cedar.  Therefore there is limited potential for an in-combination impact, and each project will have to implement their own UXO mitigation to limit injury and disturbance, thus further reducing the potential for in-combination effects of UXO clearance.
  3. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 3 projects. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 3 projects will not have an adverse effect on the integrity of the marine mammal features of the SACs assessed in this Part of the RIAA.

                        Construction phase

                        Berwickshire and North Northumberland Coast SAC
Grey seal

                        Tier 1

  1. Of the two Tier 1 projects identified, only Berwick Bank has a publicly available EIA Report and RIAA (SSE Renewables, 2022c, SSE Renewables, 2022e). The RIAA concluded that effects caused by UXO clearance are considered unlikely to cause a change in reproduction and survival rates or alteration in the distribution of the population of grey seal from the Berwickshire and North Northumberland Coast SAC (SSE Renewables, 2022e). Given that this effect is short in duration, connectivity with important habitats within and outside the site is also unlikely to be impaired. Considering the number of animals potentially affected by PTS and TTS, respective proportions of the SAC population potentially affected and designed in measures reducing the risk of adverse effects, it was concluded highly unlikely that UXO clearance would influence grey seal of Berwickshire and North Northumberland population trajectory in the long-term (SSE Renewables, 2022e).
  2. The Tier 1 assessment, presented in paragraphs 841 et seq., concluded that injury and disturbance as a result of underwater noise from in-combination UXO clearance in the construction phase are unlikely to occur. Given that the risk of injury will be reduced by the appropriate standard industry measures at respective projects to reduce the risk of PTS to marine mammals, the in-combination risk of injury is expected to be reduced further. At the Array alone, with designed-in measures applied ( Table 6.19   Open ▸ ), it is anticipated that grey seal would be deterred from the injury zone and therefore the likelihood of PTS and population-level effects would be unlikely. As per the assessment of the Array alone (section 6.3.2), it is also expected that grey seals would move beyond the injury range, thereby reducing the risk of PTS. Grey seals are likely to be able to tolerate the in-combination behavioural disturbance without any risk to the populations (such as by fleeing the affected area), reproduction or survival rates and would be able to return to previous behavioural states or activities once the impacts had ceased.

                        Tier 2

  1. The Tier 2 assessment, presented in paragraphs 858 et seq., concluded that in-combination effects as a result of underwater noise from UXO clearance in the construction phase are unlikely to occur. It is expected that the risk of injury will be reduced by standard industry measures (including visual and acoustic monitoring) at respective projects. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 2 projects. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 2 projects will not have an adverse effect on the integrity of the grey seal feature of this SAC.

                        Tier 3

  1. The Tier 3 assessment, presented in paragraphs 865 et seq., highlighted that it was not possible to confirm with any degree of certainty whether there would be overlap in UXO clearance with Ossian construction activities and the nine Tier 3 projects identified for this impact. This was due to the lack of publicly available information surrounding piling parameters and lack of knowledge in general about INTOG projects. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 3 .
  2. There is no publicly available UXO clearance parameters or published assessments for Tier 3 projects (which are at pre-scoping stage), however given the phase of development there is likely to be no temporal overlap with the Array. Furthermore, given the maximum un-mitigated UXO injury ranges for grey seal from the Array (maximum PTS range of 2,850 m, 6,120 m for TTS) there is low likelihood of any spatial overlap of ranges between the Array and Campion, Flora Floating Wind Farm, Aspen and Cedar. Therefore there is limited potential for an in-combination impact, and each project will have to implement their own UXO mitigation to limit injury and disturbance, thus further reducing the potential for in-combination effects of UXO clearance.
  3. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 3 projects will not have an adverse effect on the integrity of the grey seal feature of this SAC.

                        Conclusion

  1. Adverse effects on the qualifying Annex II marine mammal features of the Berwickshire and North Northumberland Coast SAC which undermine the conservation objectives of the SAC will not occur as a result of in-combination underwater noise generated during UXO clearance in the construction phase. Potential effects from this activity on the relevant conservation objectives (as presented in section 6.2.1) are discussed in turn below in Table 6.70   Open ▸ .

 

Table 6.70:
Conclusions Against the Conservation Objectives of the Berwickshire and North Northumberland Coast SAC from Underwater Noise Generated During UXO Clearance in the Construction Phase of the Array In-Combination with other Plans and Projects

Table 6.70: Conclusions Against the Conservation Objectives of the Berwickshire and North Northumberland Coast SAC from Underwater Noise Generated During UXO Clearance in the Construction Phase of the Array In-Combination with other Plans and Projects

 

  1. It can be concluded, beyond reasonable scientific doubt, that there is no risk of an adverse effect on the integrity of the Berwickshire and North Northumberland Coast SAC as a result of underwater noise generated during UXO clearance in the construction phase of the Array in-combination with other plans and projects.
                        Southern North Sea SAC
Harbour porpoise

                        Tier 1

  1. Of the two Tier 1 projects identified, only Berwick Bank has a publicly available EIA Report and RIAA (SSE Renewables, 2022c, SSE Renewables, 2022e). The RIAA concluded that effects caused by UXO clearance are considered unlikely to cause a change in reproduction and survival rates or alteration in the distribution of the population of harbour porpoise from the Southern North Sea SAC (SSE Renewables, 2022e). UXO clearance activities associated with Berwick Bank will not take place within or nearby to the Southern North Sea SAC (146 km south from Berwick Bank), and therefore will not exclude harbour porpoise from the relevant area of the site (SSE Renewables, 2022e). The Berwick Bank RIAA concluded that behavioural disturbance as a result of UXO clearance is unlikely to alter the distribution of harbour porpoise such that recovery cannot be expected or that effects on Southern North Sea SAC population could be considered long term (SSE Renewables, 2022e). Additionally, since there was no potential for modelled injury ranges or disturbance contours associated with Berwick Bank to reach the SAC, it will not affect foraging habitats and areas important for breeding and calving within the SAC (SSE Renewables, 2022e).
  2. The Tier 1 assessment, presented in paragraphs 841 et seq., concluded that injury and disturbance as a result of in-combination UXO clearance in the construction phase are unlikely to occur. Given that the risk of injury will be reduced by the appropriate standard industry measures at respective projects to reduce the risk of PTS to marine mammals, the in-combination risk of injury is expected to be reduced further. At the Array alone, with designed-in measures applied ( Table 6.19   Open ▸ ), it is anticipated that all species except harbour porpoise would be deterred from the injury zone and therefore the likelihood of PTS and population-level effects would be unlikely. However, following the application of secondary mitigation tailored to take account of the size and number of UXO following further site-specific survey work (paragraph 580), the risk of in-combination impact is considered to be low. Therefore application of secondary mitigation will reduce the Array’s contribution to any in-combination impact resulting from auditory injury on harbour porpoise in the North Sea MU to a non-significant level (i.e., the in-combination assessment takes into account the Array alone commitments (see paragraphs 580 et seq.). Therefore, with the residual magnitude for harbour porpoise for both the Array alone and Berwick Bank Wind Farm as low in their respective EIA Reports, it is anticipated that the in-combination impact will be reduced to a non-significant level. Considering that only up to 29 UXOs cumulatively from Tier 1 projects ( Table 6.68   Open ▸ ) require clearing and with low order techniques being prioritised, it is expected that UXO clearance would not manifest to population-level effects due to the small proportion of the North Sea MU potentially affected.
  3. As undertaken for the assessment of the Array alone, the EDR approach has also been used for the assessment of disturbance associated with UXO clearance during the construction phase for harbour porpoise features in-combination with other plans and projects. Only two in-combination projects were relevant for inclusion: Berwick Bank Wind Farm (Tier 1) and Morven Offshore Wind Farm (Tier 2). This is based on their proximity to the site boundary and public availability of their potential UXO parameters. Although there are some Tier 3 projects in close proximity to the site boundary (such as Bellrock and Bowdun Offshore Wind Farms), there are no publicly available documents, and the construction schedules are still unknown, so it is not possible to confirm with any degree of certainty whether there would be overlap in UXO clearance with Ossian construction activities. As per the JNCC (2020) guidance, 26 km EDRs have been plotted for Berwick Bank Wind Farm and Morven Offshore Wind Farm ( Figure 6.15   Open ▸ ) to assess the potential for in-combination disturbance to the Southern North Sea SAC. It should be noted that as individual UXO locations are not currently available for these projects (or for the Array), and so the 26 km EDRs have been drawn from the southernmost tip of respective project boundaries, which would be the closest possible location to the Southern North Sea SAC. Therefore, these EDRs may be over precautionary as UXO detonations may be concentrated further away from the SAC. Given that there is no overlap between these EDRs and the Southern North Sea SAC ( Figure 6.15   Open ▸ ), the conclusion that there will not be an in-combination impact to this SAC is further supported.

                        Tier 2

  1. The Tier 2 assessment, presented in paragraphs 858 et seq., concluded that in-combination effects as a result of UXO clearance in the construction phase are unlikely to occur. It is expected that the risk of injury will be reduced by standard industry measures (including visual and acoustic monitoring) at respective projects. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 2 projects. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 2 projects will not have an adverse effect on the integrity of the harbour porpoise feature of this SAC.

                        Tier 3

  1. The Tier 3 assessment, presented in paragraphs 865 et seq., highlighted that it was not possible to confirm with any degree of certainty whether there would be overlap in UXO clearance with Ossian construction activities and the nine Tier 3 projects identified for this impact. This was due to the lack of publicly available information surrounding piling parameters and lack of knowledge in general about INTOG projects. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 3 projects.
  2. There is no publicly available UXO clearance parameters or published assessments for Tier 3 projects (which are at pre-scoping stage), however given the phase of development there is likely to be no temporal overlap with the Array. Furthermore, given the maximum un-mitigated UXO injury ranges for harbour porpoise from the Array (maximum PTS range of 14.5 km, 26.7 km for TTS) there is low likelihood of any spatial overlap of ranges between the Array and Campion, Flora Floating Wind Farm, Aspen and Cedar. Therefore, there is limited potential for an in-combination impact, and each project will have to implement their own UXO mitigation to limit injury and disturbance, thus further reducing the potential for in-combination effects of UXO clearance.
  3. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 3 projects will not have an adverse effect on the integrity of the harbour porpoise feature of this SAC.

                        Conclusion

  1. Adverse effects on the qualifying Annex II marine mammal features of the Southern North Sea SAC which undermine the conservation objectives of the SAC will not occur as a result of in-combination underwater noise generated during UXO clearance in the construction phase. Potential effects from this activity on the relevant conservation objectives (as presented in section 6.2.2) are discussed in turn below in Table 6.71   Open ▸ .

Figure 6.15:
Maximum Spatial Overlap of Underwater Noise Impacts upon the Southern North Sea SAC from In-Combination UXO Clearance with the Array and Relevant Plans and Projects Based on the 26 km EDR Approach

Figure 6.15: Maximum Spatial Overlap of Underwater Noise Impacts upon the Southern North Sea SAC from In-Combination UXO Clearance with the Array and Relevant Plans and Projects Based on the 26 km EDR Approach


Table 6.71:
Conclusions Against the Conservation Objectives of the Southern North Sea SAC from Underwater Noise Generated During UXO Clearance in the Construction Phase of the Array In-Combination with other Plans and Projects.

Table 6.71: Conclusions Against the Conservation Objectives of the Southern North Sea SAC from Underwater Noise Generated During UXO Clearance in the Construction Phase of the Array In-Combination with other Plans and Projects.

  1. It can be concluded, beyond reasonable scientific doubt, that there is no risk of an adverse effect on the integrity of the Southern North Sea SAC as a result of underwater noise generated during UXO clearance in the construction phase of the Array in-combination with other plans and projects.
                        Moray Firth SAC
Bottlenose dolphin

                        Tier 1

  1. Of the two Tier 1 projects identified, only Berwick Bank has a publicly available EIA Report and RIAA (SSE Renewables, 2022c, SSE Renewables, 2022e). The Berwick Bank RIAA concluded that the TTS ranges do not extend to the Moray Firth SAC and only small number of animals may experience TTS within the Coastal East Scotland MU. Therefore disturbance will not be significant (SSE Renewables, 2022e). The Berwick Bank RIAA concluded will be no disturbance with areas used by dependant mothers and calves, therefore it is highly unlikely that the reproductive and recruitment capability of the species will be affected (SSE Renewables, 2022e).
  2. The Tier 1 assessment, presented in paragraphs 841 et seq., concluded that injury and disturbance as a result of in-combination UXO clearance in the construction phase are unlikely to occur. Given that the risk of injury will be reduced by the appropriate standard industry measures at respective projects to reduce the risk of PTS to marine mammals, the in-combination risk of injury is expected to be reduced further. At the Array alone, with designed-in measures applied ( Table 6.19   Open ▸ ), it is anticipated that bottlenose dolphin would be deterred from the injury zone and therefore the likelihood of PTS and population-level effects would be unlikely. As per the assessment of the Array alone (section 6.3.2), it is also expected that bottlenose dolphins would move beyond the injury range. Bottlenose dolphins are likely to be able to tolerate the in-combination effect without any potential impact on either reproduction or survival rates and would be able to return to previous behavioural states or activities once the impacts had ceased.

                        Tier 2

  1. The Tier 2 assessment, presented in paragraphs 858 et seq., concluded that in-combination effects as a result of UXO clearance in the construction phase are unlikely to occur. It is expected that the risk of injury will be reduced by standard industry measures (including visual and acoustic monitoring) at respective projects. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 2 projects. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 2 projects will not have an adverse effect on the integrity of the bottlenose dolphin feature of this SAC.

                        Tier 3

  1. The Tier 3 assessment, presented in paragraphs 865 et seq., highlighted that it was not possible to confirm with any degree of certainty whether there would be overlap in UXO clearance with Ossian construction activities and the nine Tier 3 projects identified for this impact. This was due to the lack of publicly available information surrounding piling parameters and lack of knowledge in general about INTOG projects. The CEA presented in the Array EIA Report (volume 2, chapter 10 of the Array EIA Report) concluded a minor significance of effect for this potential impact associated with the Tier 3 projects.
  2. There is no publicly available UXO clearance parameters or published assessments for Tier 3 projects (which are at pre-scoping stage), however given the phase of development there is likely to be no temporal overlap with the Array. Furthermore, given the maximum un-mitigated UXO injury ranges for bottlenose dolphin from the Array (maximum PTS range of 840 m, 1,550 m for TTS) there is low likelihood of any spatial overlap of ranges between the Array and Campion, Flora Floating Wind Farm, Aspen and Cedar. Therefore, there is limited potential for an in-combination impact, and each project will have to implement their own UXO mitigation to limit injury and disturbance, thus further reducing the potential for in-combination effects of UXO clearance.
  3. Based on this, it is concluded that in-combination UXO clearance at the Array and the Tier 3 projects will not have an adverse effect on the integrity of the bottlenose dolphin feature of this SAC.

                        Conclusion

  1. Adverse effects on the qualifying Annex II marine mammal features of the Moray Firth SAC which undermine the conservation objectives of the SAC will not occur as a result of in-combination underwater noise generated during UXO clearance in the construction phase. Potential effects from this activity on the relevant conservation objectives (as presented in section 6.2.3) are discussed in turn below in Table 6.72   Open ▸ .

Table 6.72:
Conclusions Against the Conservation Objectives of the Moray Firth SAC from Underwater Noise Generated During UXO Clearance in the Construction Phase of the Array In-Combination with other Plans and Projects.

Table 6.72: Conclusions Against the Conservation Objectives of the Moray Firth SAC from Underwater Noise Generated During UXO Clearance in the Construction Phase of the Array In-Combination with other Plans and Projects.

 

  1. It can be concluded, beyond reasonable scientific doubt, that there is no risk of an adverse effect on the integrity of the Moray Firth SAC as a result of underwater noise generated during UXO clearance in the construction phase of the Array in-combination with other plans and projects.