6.4.4. Disturbance due to Site-Investigation Surveys (Including Geophysical Surveys)

894. The LSE2 assessment during the HRA Stage One process identified that LSE2 could not be ruled out for disturbance due to site investigation surveys (including geophysical surveys) in the construction and operation and maintenance phases 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.

895. The risk of injury in terms of PTS to marine mammal receptors as a result of underwater noise due to site-investigation surveys would be expected to be localised to within the boundaries of the respective projects. The assessment for the Array alone found that the maximum impact range was 310 m for geophysical surveys and 45 m for geotechnical surveys (based on harbour porpoise) and this highly localised, with numbers of animals impacted will be extremely low (section 6.3.3). Furthermore, any risk of injury will be mitigated via the MMMP (volume 4, appendix 22 of the Array EIA Report) and there will no potential for in-combination injury. The in-combination assessment provided in this section therefore focuses on disturbance only.
896. The MDS considered for this in-combination assessment is shown in Table 6.73   Open ▸ . The designed in measures are presented in Table 6.33   Open ▸ for the assessment of the Array alone.

 Table 6.73: MDS Considered for the Assessment of Potential Impacts to Annex II Marine Mammals due to Disturbance due to Site-Investigation Surveys in the Construction and Operation and Maintenance Phases of the Array In-Combination with other Plans and Projects

                        In-combination assessment

897. There is the potential for in-combination impacts from site-investigation surveys in the construction and operation and maintenance phases 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 6.73   Open ▸ .

                        Tier 1

898. One Tier 1 project was identified with potential for in-combination effects associated with this potential impact within the 50 km buffer, during the construction and operation and maintenance phases:

• Proposed offshore export cable corridor(s) (construction and operation and maintenance phases) ( Table 6.73   Open ▸ ).

899. As discussed in section 4.6, 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 of the in-combination impact from site-investigation surveys. It can be reasonably assumed the extent of the impacts for the Proposed offshore export cable corridor(s) are expected to be similar to those of the Array alone (see section 6.3.3), as, whilst the geographical location of the geophysical survey areas of other projects will differ, the extent of the disturbance per survey equipment at any one point will likely be very similar. The construction phase (and associated pre-construction surveys) of the Proposed offshore export cable corridor(s) (2030 to 2037) overlaps with that of the Array and therefore there is the potential for temporal overlap in site-investigation surveys. However, it should be noted that site-investigation survey equipment will not be operating continuously, it will be used when required for investigations of particular areas of the seabed where additional information is required to inform the construction. Site-investigation surveys for Proposed offshore export cable corridor(s) are likely to be carried out at the start of the construction phase (2030) and therefore direct overlap with the site-investigation surveys for the Array is unlikely (particularly given the need for limited resource to undertake site-investigation surveys).
900. For the Array alone, the maximum disturbance range across all geophysical surveys was estimated as 1,340 m (SBP) activity and the maximum range across geotechnical activities was 9,101 m (vibrocoring) for all species (see section 6.3.3). Given that the distance between the Array and the Proposed offshore export cable corridor(s) is less than the estimated disturbance ranges from geophysical surveys, there is potential for spatial overlap. However, the likelihood of temporal overlap of site investigation surveys at these projects is very low, and it is therefore unlikely, due to the temporal separation, that site-investigation surveys at the Array and Proposed offshore export cable corridor(s) will spatially overlap at any one time.
901. Site-investigation surveys are anticipated to be short term in nature (weeks to a few months) and occur intermittently over the construction phase. For example, the site-investigation surveys for the Array will be carried out over 5 months within a 3 year period.
902. This potential impact has also been considered for the operation and maintenance phase. For the Array, routine geophysical surveys will take place once every 24 months for wind turbines and OSP foundations as well as wind turbines interior and exterior. For inter-array cables and interconnector cables routine geophysical surveys will be undertaken annually for the first three years, then every 24 months. The duration of routine geophysical survey campaign is up to three months. It is possible that routine geophysical surveys for the Proposed offshore export cable corridor(s) will be similar to those of the inter-array cables and interconnector cables for the Array and therefore, there is potential for geophysical surveys during the operation and maintenance phase to temporally overlap with the Proposed offshore export cable corridor(s). As for the construction phase, surveys are anticipated to be short term in nature (weeks to a few months) and occur intermittently over the operation and maintenance phase.
903. For construction and operation and maintenance activities, it is likely that the Proposed offshore export cable corridor(s) will also include an MMMP as a designed in measure, similar to that adopted for the Array alone ( Table 6.33   Open ▸ ). While this primarily mitigates against injury (which has not been assessed in-combination, see paragraph 895) it will also aid in reducing disturbance to marine mammals. In addition, this potential impact is of high reversibility, with animals returning to baseline levels shortly after surveys have ceased. As such, and in consideration of the potential designed in measure of an MMMP, population-level effects associated with this potential impact are unlikely for the marine mammal features of the SACs.

                        Tier 2

904. In addition to Tier 1 projects, one Tier 2 project was identified with potential for in-combination effects associated with this impact, which lies within the 50 km buffer used for site-investigation surveys:

• Morven Offshore Wind Farm ( Table 6.73   Open ▸ ).

905. Disturbance to marine mammals from pre-construction site-investigation surveys is scoped in for Morven Offshore Wind Farm (Morven Offshore Wind Limited, 2023). The Scoping Report details comparative sound modelling for geophysical activities will be undertaken to inform an assessment of possible effects from elevated levels of underwater noise. At this point in time, there is not quantitative information upon which to take a more detailed assessment of site-investigation surveys. The site boundary lies, at the closest point, 5.5 km from the Morven Array and based on the maximum disturbance range predicted for the Array (9,101 m for vibrocoring for all species) there is potential for spatial overlap between these two projects for vibrocoring surveys. However, the likelihood of temporal overlap of site investigation surveys at the Array and Morven Offshore Wind Farm is very low (e.g. there are limitations on the number of survey vessels that could carry out such surveys at one time) and it is therefore unlikely, due to the temporal separation, that site-investigation surveys at Morven Offshore Wind Farm would overlap with the area disturbed during site-investigation surveys at the Tier 1 project, Proposed offshore export cable corridor(s) (see paragraph 631 for detail). Within the Morven Offshore Wind farm Scoping Report (Morven Offshore Wind Limited, 2023), this potential impact was not scoped in for the operation and maintenance phase, and has thus not been discussed further in this Tier 2 assessment.
906. For construction activities, it is likely that Morven Offshore Wind Farm will also include an MMMP as a designed in measure, similar to that adopted for the Array alone ( Table 6.33   Open ▸ ). While this primarily mitigates against injury (which has not been assessed in-combination, see paragraph 895) it will also aid in reducing disturbance to marine mammals. In addition, behavioural disturbance is of high reversibility, with animals returning to baseline levels shortly after surveys have ceased. As such, and in consideration of the potential designed in measure of an MMMP, population-level effects associated with this potential impact are considered unlikely for the marine mammal features of the SACs.

                        Tier 3

907. Four Tier 3 projects were identified with potential for in-combination effects associated with this impact, which lie within the 50 km buffer used for site-investigation surveys:

• Bellrock Offshore Wind Farm;
• Bowdun Offshore Wind Farm;
• Campion Offshore Wind Farm;
• Morven Offshore Export Cable Corridor(s) ( Table 6.73   Open ▸ ).

908. Tier 3 projects are in a pre-application phase and no EIA Scoping Report, EIA Report, or HRA documentation are available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
909. Whilst there is no information on the timeline for construction at Bellrock Offshore Wind Farm and therefore it cannot be excluded from the in-combination assessment, the likelihood of direct temporal overlap with site-investigation surveys at Bellrock Offshore Wind Farm and the Array is unlikely given the different stages of status of development. Furthermore, surveys are likely to be short term and intermittent and disturbance ranges associated with these projects would be highly localised. Bellrock Offshore Wind Farm is located 8.57 km north-west from the Array and therefore site-investigation surveys will have no spatial overlap given the small disturbance ranges presented for the Array assessment (see section 6.3.3).
910. Whilst there is no information on the timeline for construction at Bowdun Offshore Wind Farm and therefore it cannot be excluded from the in-combination assessment, the likelihood of direct temporal overlap with site-investigation surveys at Bowdun Offshore Wind Farm and the Array is unlikely given the different stages of status of development. Furthermore, surveys are likely to be short term and intermittent and disturbance ranges associated with these projects would be highly localised. Bowdun Offshore Wind Farm is located 25.35 km north-west from the Array and therefore site-investigation surveys will have no spatial overlap given the small disturbance ranges presented for the Array assessment (see section 6.3.3).
911. The likelihood of direct temporal overlap with site-investigation surveys at Campion Offshore Wind and the Array is unlikely given the different stages of status of development. Furthermore, surveys are likely to be short term and intermittent and disturbance ranges associated with these projects would be highly localised. Campion Offshore Wind Farm is located 44.15 km north-east from the Array and therefore site-investigation surveys will have no spatial overlap given the small disturbance ranges presented for the Array assessment (see section 6.3.3).
912. Further, site-investigation surveys associated with the Morven Offshore Export Cable Corridor(s) are likely to occur during its construction phase, however it is unknown whether they will persist over the operation and maintenance phase, as is assumed for the Tier 3 offshore wind farm projects. It is likely that these surveys will be completed prior to those associated with the construction of the Array, however, overlap has been assumed as a precaution.
913. For site-investigation surveys, it is likely that Tier 3 projects will also include an MMMP as a designed in measure, similar to that adopted for the Array alone ( Table 6.33   Open ▸ ). While this primarily mitigates against injury (which has not been carried forward for assessment in-combination, see paragraph 895) it will also aid in reducing disturbance to marine mammals. In addition, behavioural disturbance is of high reversibility, with animals returning to baseline levels shortly after surveys have ceased. As such, and in consideration of the potential designed in measure of an MMMP, population-level effects associated with this potential impact are unlikely for the marine mammal features of the SACs.

                        Construction and operation and maintenance phases

                        Berwickshire and North Northumberland Coast SAC

Grey seal

                        All Tiers

914. There was no species or SAC specific information available for any of projects identified for in-combination effects for this impact, therefore all Tiers have been addressed here.
915. As detailed in paragraphs 898 et seq., site-investigation surveys for the Tiers 1, 2, and 3 projects are expected to be short term in nature and occur intermittently. In addition, behavioural disturbance is of high reversibility, with animals returning to baseline levels shortly after surveys have ceased. As per the values modelled for the Array alone (section 6.3.3), disturbance ranges are likely to be within the metres to low kilometres depending on the survey technique. For the Array alone, the maximum disturbance range across all geophysical surveys was estimated as 1,340 m for SBP activity and the maximum range across geotechnical activities was 9,101 m for vibrocoring) for all species (see Table 6.37   Open ▸ ). Therefore, the potential for in-combination effects is reduced, particularly for projects that are tens of kilometres away from the site boundary (such as Bowdun and Campion Offshore Wind Farms in Tier 3). In-combination behavioural disturbance ranges are therefore highly unlikely to overlap with the Berwickshire and North Northumberland Coast SAC, which is a minimum of 113.95 km south-west from the site boundary.
916. For construction and operation and maintenance activities, it is likely that the Tier 1, 2, and 3 projects will also include an MMMP as a designed in measure, similar to that adopted for the Array alone ( Table 6.33   Open ▸ ). As such, and in consideration of the potential designed in measure of an MMMP, population-level effects associated with this potential impact are unlikely for the grey seal feature of this SAC.

                        Conclusion

917. 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 disturbance due to site-investigation surveys during the construction and operation and maintenance phases. Potential effects from this activity on the relevant conservation objectives (as presented in section 6.2.1) are discussed in turn below in Table 6.74   Open ▸ .

Table 6.74: Conclusions Against the Conservation Objectives of the Berwickshire and North Northumberland Coast SAC from Disturbance due to Site-Investigation Surveys (Including Geophysical Surveys) during the Construction and Operation and Maintenance Phases of the Array In-Combination with other Plans and Projects

918. 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 disturbance due to site-investigation surveys during the construction and operation and maintenance phases of the Array in-combination with other plans and projects.

                        Southern North Sea SAC

Harbour porpoise

                        All Tiers

919. There was no species or SAC specific information available for any of projects identified for in-combination affects for this impact, therefore all Tiers have been addressed here.
920. As detailed in paragraphs 898 et seq., site-investigation surveys for the Tiers 1, 2, and 3 projects are expected to be short term in nature and occur intermittently. In addition, this potential impact is of high reversibility, with animals returning to baseline levels shortly after surveys have ceased. As per the values modelled for the Array alone (section 6.3.3), disturbance ranges are likely to be within the metres to low kilometres depending on the survey technique. For the Array alone, the maximum disturbance range across all geophysical surveys was estimated as 1,340 m for SBP activity and the maximum range across geotechnical activities was 9,101 m for vibrocoring) for all species (see Table 6.37   Open ▸ ). Therefore, the potential for in-combination effects is reduced, particularly for projects that are tens of kilometres away from the site boundary (such as Bowdun and Campion Offshore Wind Farms in Tier 3). In-combination behavioural disturbance ranges are therefore highly unlikely to overlap with the Southern North Sea SAC, which is a minimum of 129.86 km south-east from the site boundary.
921. For construction and operation and maintenance activities, it is likely that the Tier 1, 2, and 3 projects will also include an MMMP as a designed in measure, similar to that adopted for the Array alone ( Table 6.33   Open ▸ ). As such, and in consideration of the potential designed in measure of an MMMP, population-level effects associated with this potential impact are unlikely for the harbour porpoise feature of this SAC.

                        Conclusion

922. 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 disturbance due to site-investigation surveys during the construction and operation and maintenance phases. Potential effects from this activity on the relevant conservation objectives (as presented in section 6.2.2) are discussed in turn below in Table 6.75   Open ▸ .

Table 6.75: Conclusions Against the Conservation Objectives of the Southern North Sea SAC from Disturbance due to Site-Investigation Surveys (Including Geophysical Surveys) during the Construction and Operation and Maintenance Phases of the Array In-Combination with other Plans and Projects

923. 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 disturbance due to site-investigation surveys during the construction and operation and maintenance phases of the Array in-combination with other plans and projects.

                        Moray Firth SAC

Bottlenose dolphin

                        All Tiers

924. There was no species or SAC specific information available for any of projects identified for in-combination affects for this impact, therefore all Tiers have been addressed here.
925. As detailed in paragraphs 898 et seq., site-investigation surveys for the Tiers 1, 2, and 3 projects are expected to be short term in nature and occur intermittently. In addition, this potential impact is of high reversibility, with animals returning to baseline levels shortly after surveys have ceased. As per the values modelled for the Array alone (section 6.3.3), disturbance ranges are likely to be within the metres to low kilometres depending on the survey technique. For the Array alone, the maximum disturbance range across all geophysical surveys was estimated as 1,340 m for SBP activity and the maximum range across geotechnical activities was 9,101 m for vibrocoring) for all species (see Table 6.37   Open ▸ ). Therefore, the potential for in-combination effects is reduced, particularly for projects that are tens of kilometres away from the site boundary (such as Bowdun and Campion Offshore Wind Farms in Tier 3). In-combination behavioural disturbance ranges are therefore highly unlikely to overlap with the Moray Firth SAC, which is a minimum of 175.86 km north-west from the site boundary.
926. For construction and operation and maintenance activities, it is likely that the Tier 1, 2, and 3 projects will also include an MMMP as a designed in measure, similar to that adopted for the Array alone ( Table 6.33   Open ▸ ). As such, and in consideration of the potential designed in measure of an MMMP, population-level effects associated with this potential impact are unlikely for the bottlenose dolphin feature of this SAC.

                        Conclusion

927. 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 disturbance due to site-investigation surveys during the construction and operation and maintenance phases. Potential effects from this activity on the relevant conservation objectives (as presented in section 6.2.3) are discussed in turn below in Table 6.76   Open ▸ .

Table 6.76: Conclusions Against the Conservation Objectives of the Moray Firth SAC from Disturbance due to Site-Investigation Surveys (Including Geophysical Surveys) during the Construction and Operation and Maintenance Phases of the Array In-Combination with other Plans and Projects

928. 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 disturbance due to site-investigation surveys during the construction and operation and maintenance phases of the Array in-combination with other plans and projects.

6.4.5. Changes in Prey Availability

929. The LSE2 assessment during the HRA Stage One process identified that LSE2 could not be ruled out for changes in prey availability due to underwater noise from piling and 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.

930. The MDS considered for this in-combination assessment is shown in Table 6.77   Open ▸ . The designed in measures are presented in Table 6.43   Open ▸ for the assessment of the Array alone.

 Table 6.77: MDS Considered for the Assessment of Potential Impacts to Annex II Marine Mammals due to Changes in Prey Availability in the Construction Phase of the Array In-Combination with other Plans and Projects

                        In-combination assessment

931. There is the potential for in-combination impacts due to changes in prey availability 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 6.77   Open ▸ .
932. As concluded in the Array HRA Stage One LSE2 Screening Report (Array RIAA Part 1, appendix 1A) Annex II grey seal, harbour porpoise, and bottlenose dolphin are likely to be present within the Array marine mammal study area and may forage within the area. Effects on prey fish populations across all phases of the Array alone, and in-combination with other plans and projects, are likely to be temporary, of a short duration, localised and not significant (as per the conclusions presented for the assessment on Annex II diadromous fish; section 5.3). The widest ranging effect was concluded to be of increased underwater noise during the construction phase (mainly due to piling) and is unlikely to be significant in other phases (Array RIAA Part 1, appendix 1A). However, as impacts to prey species have been assessed as part of the underwater noise modelling assessment that has been undertaken for the EIA, this potential impact was included for the construction phase in the in-combination assessment as a precaution for the Annex II marine mammal features of their respective SACs.

                        Tier 1

933. There were two Tier 1 projects identified with potential for in-combination effects associated with this impact:

• Proposed offshore export cable corridor(s); and
• Berwick Bank Offshore Wind Farm ( Table 6.77   Open ▸ ).

934. Currently, there is no EIA Report available for the Proposed offshore export cable corridor(s), though construction is likely to be of medium duration, with noise being intermittent. Although there is no information on construction activities associated with the Proposed offshore export cable corridor(s), it is not expected that piling will be included in the project description (as this is a cable project). As such, noise impacts which have the potential to affect prey species are expected to be limited to UXO clearance operations during site preparation. While there is no site-specific information on these impacts, it is expected they would be similar to those assessed for the project alone (i.e. minor significance, see volume 2, chapter 9 of the EIA Report).
935. The Berwick Bank Offshore Wind Farm underwater noise assessment considered effects (including mortality, injury and behavioural effects) on a similar range of fish and shellfish receptors as the Array alone (volume 2, chapter 9 of the Array EIA Report). The Berwick Bank assessment predicted that injurious effects on fish would be limited in extent and behavioural effects would occur across a wider area of up to tens of kilometres (SSE Renewables, 2022b). The effects would be temporary, reversible and would not result in significant effects on fish and shellfish receptors (SSE Renewables, 2022b). In the marine mammal assessment for the Berwick Bank EIA, changes in prey availability was therefore concluded to be of minor adverse significance for all species (SSE Renewables, 2022c).
936. The construction of the Array, and of Berwick Bank Offshore Wind Farm, will coincide for only two years (2031 and 2032). Furthermore, due to the large distance between the projects (56.84 km), there is limited potential for noise contours to interact. Given that UXO clearance is typically undertaken at the beginning of the construction phase, there is likely to be no temporal overlap in UXO clearance associated with the Array and Berwick Bank Offshore Wind Farm (where the construction phase is currently anticipated as 2025 to 2032 ( Table 6.57   Open ▸ ).
937. It is likely that the Tier 1 projects will involve similar designed in mitigation as the Array ( Table 6.43   Open ▸ ), such as piling soft starts and low order UXO disposal. These will reduce the risk of injury to prey fish species in the immediate vicinity of piling or UXO operations, either by allowing some species/individuals to flee the area before noise levels reach a level at which injury may occur, and/or by limiting the total amount of noise energy entering the environment.
938. With respect to indirect effects on marine mammals, no additional in-combination effects due to changes in prey availability are predicted (with no significant cumulative effects predicted for fish and shellfish species in the EIA Report). As discussed in the alone assessment (section 6.3.4), all marine mammals in this assessment are considered to be generalist opportunistic feeders and are thus not reliant on a single prey species. Given that marine mammals are wide-ranging in nature with the ability to exploit numerous food sources, there would be a variety of prey species available for marine mammal foraging.

                        Tier 2

939. In addition to the Tier 1 projects, there were three Tier 2 projects identified with potential for in-combination effects associated with this impact:

• Morven Offshore Wind Farm;
• Cenos Offshore Wind Farm; and
• Salamander Offshore Wind Farm ( Table 6.77   Open ▸ ).

940. Currently, only Scoping Reports are available for the Tier 2 projects, though piling activities during their construction phases are expected to be similar in nature as that of the Array. Although information on hammer energies and piling durations are not available for the Tier 2 projects, the potential impact is likely to be of medium duration, with noise being intermittent during the construction phase. As detailed in Table 6.57   Open ▸ , the construction phase of the Morven Offshore Wind Farm is anticipated to largely overlap temporally with that of the Array, however dates are currently unavailable for the other two Tier 2 projects.
941. It is likely that the Tier 2 projects will involve similar designed in mitigation as the Array ( Table 6.43   Open ▸ ), such as piling soft starts and low order UXO disposal. These will reduce the risk of injury to prey fish species in the immediate vicinity of piling or UXO operations, either by allowing some species/individuals to flee the area before noise levels reach a level at which injury may occur, and/or by limiting the total amount of noise energy entering the environment.
942. Within the fish and shellfish ecology CEA (volume 2, chapter 9 of the Array EIA Report), cumulative effects from underwater noise were assessed as being of minor adverse significance for all fish and shellfish receptors in the Tier 2 assessment. With respect to indirect effects on marine mammals, no additional in-combination effects due to changes in prey availability are predicted (as no significant cumulative effects predicted for fish and shellfish in the EIA Report). As discussed in the alone assessment (section 6.3.4), all marine mammals in this assessment are considered to be generalist opportunistic feeders and are thus not reliant on a single prey species. Given that marine mammals are wide-ranging and highly mobile in nature with the ability to exploit numerous food sources, there would be a variety of prey species available for marine mammal foraging.

                        Tier 3

943. In addition to the Tier 1 and Tier 2 projects, there were seven Tier 3 projects identified with potential for in-combination effects associated with this impact:

• Morven Offshore Export Cable Corridor(s);
• Bellrock Offshore Wind Farm;
• Bowdun Offshore Wind Farm;
• Campion Offshore Wind Farm;
• Cedar Offshore Wind Farm;
• Flora Floating Wind Farm;
• Aspen Offshore Wind Farm ( Table 6.77   Open ▸ ).

944. Tier 3 projects are in a pre-application phase and no EIA Scoping Report, EIA Report, or HRA documentation are available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
945. As these are Tier 3 projects, there are no Scoping Reports in the public domain. Therefore, there is no information available on the potential impact that these Tier 3 projects will have on prey fish species, although piling activities during the construction phase are expected to be similar in nature as that of the Array. Whilst information on hammer energies and piling durations are not available for the Tier 3 projects, the potential impact is likely to be of medium duration, with noise being intermittent during the construction phase.
946. The maximum duration of the offshore construction phase for the Array is up to eight years (2031 to 2038). There is currently no information available on the various Tier 3 projects; therefore, a precautionary assumption has been made that these may have overlapping piling phases with the Array ( Table 6.57   Open ▸ ). Therefore, there may be minimal temporal overlap between the construction activities of the Array and that of the Tier 3 projects, and thus, reduced potential for in-combination effects associated with this impact.
947. It is likely that the Tier 3 projects will involve similar designed in mitigation as the Array ( Table 6.43   Open ▸ ), such as piling soft starts and low order UXO disposal. These will reduce the risk of injury to prey fish species in the immediate vicinity of piling or UXO operations, either by allowing some species/individuals to flee the area before noise levels reach a level at which injury may occur, and/or by limiting the total amount of noise energy entering the environment.
948. Within the fish and shellfish ecology CEA (volume 2, chapter 9 of the Array EIA Report), cumulative effects from underwater noise were assessed as being of minor adverse significance for all fish and shellfish receptors in the Tier 3 assessment. With respect to indirect effects on marine mammals, no additional in-combination effects due to changes in prey availability are predicted (as no significant cumulative effects predicted for fish and shellfish in the EIA Report). As discussed in the alone assessment (section 6.3.4), all marine mammals in this assessment are considered to be generalist opportunistic feeders and are thus not reliant on a single prey species. Given that marine mammals are wide-ranging and mobile in nature with the ability to exploit numerous food sources, there would be a variety of prey species available for marine mammal foraging.

                        Construction phase

                        Berwickshire and North Northumberland Coast SAC

Grey seal

                        Tier 1

949. The results of the underwater noise modelling for the Array alone suggest that prey species may be impacted due to underwater noise up to tens of kilometres from the site boundary (volume 2, chapter 9 of the EIA Report). Similarly, ranges of injury and disturbance to prey species from piling and UXO clearance at Berwick Bank were predicted to be limited in extent, with behavioural effects potentially occurring over a wider area of up to tens of kilometres (SSE Renewables, 2022b). Although there is no information on construction activities associated with the Proposed offshore export cable corridor(s), it is expected they would be similar to those assessed for the project alone (i.e. minor significance, see volume 2, chapter 9 of the EIA Report). Therefore, underwater noise only has the potential to impact prey species over a relatively small area in terms of the regional marine mammal study area as a whole.
950. As detailed in the assessment on the Array alone (section 6.3.4), the availability of wider suitable foraging habitat across the regional marine mammal study area suggests that grey seals would not be impacted by any localised and intermittent changes in prey availability associated with the Array in-combination with the Tier 1 projects. It is expected that the grey seal population would be able to tolerate the effect without any potential impact on reproduction and survival rates.
951. Overall, this potential impact is not predicted to result in adverse effects (i.e. disruption to foraging) for the grey seal feature of this SAC as a result of the Array in-combination with the Tier 1 projects.

                        Tier 2

952. The Tier 2 assessment, presented in paragraphs 939 et seq., concluded that in-combination effects are unlikely to occur. 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 changes in prey availability associated with 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

953. The Tier 3 assessment, presented in paragraphs 943 et seq., highlighted that it was not possible to undertake any meaningful in-combination assessment for the nine Tier 3 projects identified for this impact. This was due to the lack of publicly available information surrounding piling and UXO clearance parameters. 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 changes in prey availability associated with 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

954. 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 changes in prey availability during the construction phase. Potential effects from this activity on the relevant conservation objectives (as presented in in section 6.2.1) are discussed in turn below in Table 6.78   Open ▸ .

Table 6.78: Conclusions Against the Conservation Objectives of the Berwickshire and North Northumberland Coast SAC from Changes in Prey Availability during the Construction Phase of the Array In-Combination with other Plans and Projects

955. 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 changes in prey availability in the construction phase of the Array in-combination with other plans and projects.

                        Southern North Sea SAC

Harbour porpoise

                        Tier 1

956. The results of the underwater noise modelling for the Array alone suggest that prey species may be impacted due to underwater noise up to tens of kilometres from the site boundary (volume 2, chapter 9 of the EIA Report). Similarly, ranges of injury and disturbance to prey species from piling and UXO clearance at Berwick Bank were predicted to be limited in extent, with behavioural effects potentially occurring over a wider area of up to tens of kilometres (SSE Renewables, 2022b). Although there is no information on construction activities associated with the Proposed offshore export cable corridor(s), it is expected they would be similar to those assessed for the project alone (i.e. minor significance, see volume 2, chapter 9 of the EIA Report). Therefore, underwater noise only has the potential to impact prey species over a relatively small area in terms of the regional marine mammal study area as a whole.
957. As detailed in the assessment on the Array alone (section 6.3.4), the availability of wider suitable foraging habitat across the regional marine mammal study area and the generalist feeding habits of harbour porpoise suggests that individuals would not be impacted by any localised and intermittent changes in prey availability associated with the Array in-combination with the Tier 1 projects. It is expected that the harbour porpoise population would be able to tolerate the effect without any potential impact on reproduction and survival rates.
958. Overall, this potential impact is not predicted to result in adverse effects (i.e. disruption to foraging) for the harbour porpoise feature of this SAC as a result of the Array in-combination with the Tier 1 projects.

                        Tier 2

959. The Tier 2 assessment, presented in paragraphs 939 et seq., concluded that in-combination effects are unlikely to occur. 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 changes in prey availability associated with 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

960. The Tier 3 assessment, presented in paragraphs 943 et seq., highlighted that it was not possible to undertake any meaningful in-combination assessment for the nine Tier 3 projects identified for this impact. This was due to the lack of publicly available information surrounding piling and UXO clearance parameters. 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 changes in prey availability associated with 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

961. 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 changes in prey availability during 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 6.79   Open ▸ .

Table 6.79: Conclusions Against the Conservation Objectives of the Southern North Sea SAC from Changes in Prey Availability during the Construction Phase of the Array In-Combination with other Plans and Projects

962. 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 changes in prey availability in the construction phase of the Array in-combination with other plans and projects.