Decommissioning phase

529. There are no Tier 2 projects active in the Proposed Development decommissioning phase to consider for cumulative impacts based on current knowledge. Any programme changes resulting in decommissioning overlap with the Proposed Development are considered in paragraph 482.

Tier 3

Construction phase

Magnitude of impact

Subtidal Habitat IEFs

530. The Tier 3 projects which have been identified in the CEA with the potential to result in cumulative temporary habitat loss with the Proposed Development is the Cambois connection.
531. Values for the temporary habitat disturbance/loss associated with the construction of the Cambois connection are detailed in Table 8.37   Open ▸ . The values for the Cambois connection are based on information presented in the Scoping Report submitted in October 2022.

Table 8.37: Total Area and Component Parts of Temporary Habitat Disturbance of the Relevant Tier 3 Cumulative Impact Projects in the Construction Phase of the Proposed Development

532. Figure 8.7   Open ▸ shows that the Cambois connection extends beyond the Proposed Development benthic subtidal and intertidal cumulative study area, therefore the majority of this disturbance will not spatially overlap with the Proposed Development. Up to 180 km of Cambois connection cables (i.e. four cables each up to 45 km in length) may however be installed within the Proposed Development array area which could result in up to 4.5 km2 of repeat disturbance to benthic habitats within the Proposed Development array area previously impacted during the construction of the Proposed Development. The disturbance associated with the Cambois connection cable installation will however be highly localised (25 m width of potential disturbance) and so the potential for repeat disturbance is considered low and unlikely to lead to cumulative impacts.
533. The cumulative impact is predicted to be of local spatial extent, short term duration, intermittent and high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be medium.

Firth of Forth Banks Complex MPA

534. In addition to the 4,582,171 m2 of temporary habitat disturbance from the construction of Seagreen 1 and the Seagreen 1A Project, up to 6.3 m2 of temporary habitat disturbance/loss will result from the installation of Cambois connection which represents 0.30% of the total area of the FFBC MPA or 1.16% of Berwick Bank part of the MPA. The construction phases of Seagreen 1 and Seagreen 1A Project will not however overlap with the construction of Cambois connection, and so will not interact.
535. The cumulative impact is predicted to be of regional spatial extent, medium term duration, intermittent and high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be medium.

Sensitivity of the receptor

Subtidal Habitat IEFs

536. The sensitivities of the subtidal habitat IEFs are detailed in paragraphs 498 to 503.

Firth of Forth Banks Complex MPA

537. The sensitivities of the Firth of Forth Banks Complex MPA IEFs are detailed in paragraphs 504 to 506.

Significance of the effect

Subtidal Habitat IEFs

538. Overall, for the subtidal sand and muddy sand sediments IEF, the subtidal coarse and mixed sediments IEF, moderate energy subtidal rock IEF, cobble/stony reef outside of an SAC IEF and rocky reef outside an SAC IEF the magnitude of the cumulative impact is deemed to be medium, and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of moderate adverse significance in the short term (i.e. within two years of completion of construction activities), with this decreasing to minor adverse significance in the medium to long term as the sediments and communities are predicted to recover. Therefore, minor effects are predicted in the long-term which are not significant in EIA terms.
539. Overall, for the seapens and burrowing megafauna IEF and Sabellaria reef outside of an SAC IEF, the magnitude of the cumulative impact is deemed to be medium, and the sensitivity of the receptor is considered to be high. The effect will, therefore, be of moderate adverse significance in the short term (i.e. within two years of completion of construction activities) because of the high likelihood of recovery for these communities despite an increase in disturbance which is spread over a large area, with this decreasing to minor adverse significance in the medium to long term as the sediments and communities are predicted to recover. Therefore, minor effects are predicted in the long-term which are not significant in EIA terms.

Firth of Forth Banks Complex MPA

540. Overall, for the subtidal sands and gravels IEF and the shelf banks and mounds IEF, the magnitude of the cumulative impact is deemed to be medium, and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of moderate adverse significance in the short term (i.e. within two years of completion of construction activities), with this decreasing to minor adverse significance in the medium to long term as the sediments and communities are predicted to recover. Therefore, minor effects are predicted in the long-term which are not significant in EIA terms.
541. Overall, for ocean quahog IEF the magnitude of the cumulative impact is deemed to be medium, and the sensitivity of the receptor is considered to be high. The effect will, therefore, be of moderate adverse significance in the medium term (i.e. within ten years of completion of construction activities) because of the increase in magnitude leading to more widespread disturbance, with this decreasing to minor adverse significance in the long term as the sediments and ocean quahog populations are predicted to recover. Therefore, minor effects are predicted in the long-term which are not significant in EIA terms.

Further mitigation and residual effect

542. No benthic subtidal and intertidal ecology mitigation is considered necessary for the impact of temporary habitat loss/disturbance during the operation and maintenance phase because the predicted effects, in the absence of further mitigation (beyond the designed in measures outlined in section 8.10), are not significant in EIA terms.

Operation and maintenance phase

543. The Tier 3 projects which have been identified in the CEA with the potential to result in cumulative temporary habitat loss with the operation and maintenance of the Proposed Development is Cambois connection. There are also no specific values for the operation and maintenance of Cambois connection which will occur during the operation and maintenance phase of the Proposed Development. No quantification of Tier 3 cumulative impacts is possible at this stage.as a result, no assessment of the cumulative impacts of these projects can be made.

Decommissioning phase

544. There are not any Tier 3 projects active in the Proposed Development decommissioning phase to consider for cumulative impacts based on current knowledge. Any programme changes resulting in decommissioning overlap with the Proposed Development are considered in paragraph 482.

Increased Suspended Sediment Concentrations and Associated Sediment Deposition

545. Increased suspended sediment concentrations and associated deposition may arise due to the seabed preparation, installation of the wind turbines and OSP/Offshore convertor station platform foundations, the installation and/or maintenance of inter-array cables and the offshore export cables and associated decommissioning activities. Should the other projects cited take place concurrently with the Proposed Development construction or maintenance, there is potential for cumulative increases in suspended sediment concentrations and sediment deposition.

Tier 2

Construction phase

Magnitude of impact

Subtidal Habitat IEFs

546. The magnitude of the increase in suspended sediment concentrations and associated deposition arising from the installation of wind turbines and OSP/Offshore convertor station platform foundations, inter-array cables and offshore export cables during the construction phase, has been assessed as low for the Proposed Development alone, as described in section 8.11.
547. The construction phase of the Proposed Development coincides with the construction phase of the Seagreen 1A Project and the Inch Cape Offshore Wind Farm. It is noted that the Seagreen 1A Project is due for completion in the third quarter of 2025 with the installation of wind turbines being undertaken in the final months. Therefore, the installation of cables and foundations for this project will not coincide with the Proposed Development construction phase. The Inch Cape Offshore Wind Farm will be in the final year of construction, with the installation of the offshore export cables being programmed for the period of overlap. The offshore export cable corridor for Inch Cape is located to the east of the Proposed Development, beyond the Firth of Forth Banks Complex MPA and should trenching activities be undertaken simultaneously the sediment plumes would not interact with those from the Proposed Development.
548. During the Proposed Development’s construction phase the Neart na Gaoithe Offshore Wind Farm and the Seagreen 1A Export Cable will be in the operational phase and maintenance activities may result in increased SSCs, however these activities would be of limited spatial extent and frequency and unlikely to interact with sediment plumes from the Proposed Development.
549. The Eastern Link 1 Cable has Scottish landfall near Thorntonloch Beach, East Lothian. The landfall installation is proposed to be by HDD and although it is not yet confirmed which subsea trenching techniques will be used to install the cables, it is anticipated that mechanical ploughing or cutting and/or water jetting or Mass Flow Excavation (MFE) techniques will be used at different points along the route, in response to the seabed sediment conditions. Installation of the cables into soft sediments will seek to achieve a target burial depth of at least 1.5 m to 2 m and below the depth of mobile sediments depending on the nature of the seabed and potential hazards.
550. The Eastern Link 2 Cable runs to the east of the Proposed Development, skirting the FFBC MPA. For the extent of the overlap with the benthic subtidal and intertidal ecology cumulative study area this is an offshore marine cable. The preferred subsea cable protection method is burial through trenching. It is not yet confirmed what subsea trenching equipment will be used to install the cables; however, it is anticipated similar methods to those proposed for Eastern Link 1 may be required, but this is dependent on the seabed conditions present within the Proposed Development export cable corridor.
551. The CEA considers sea disposal of dredged material at the Eyemouth disposal site, located 31 km and 16.5 km from the Proposed Development array area and Proposed Development export cable corridor respectively. If offshore cable installation and dredge material deposition coincided both resultant plumes would be advected on the tidal currents, they would travel in parallel, and not towards one another, and are unlikely to interact in the event that offshore cable installation coincides with the use of the licensed sea disposal site.
552. The cumulative impact is predicted to be of local spatial extent, short term duration and intermittent and of high reversibility. The additional impact of the cumulative projects is negligible therefore the magnitude considered to be low.

Intertidal Habitat IEFs

553. The magnitude of the increase in suspended sediment concentrations and associated deposition arising from the installation of wind turbines and OSP/Offshore convertor station platform foundations, inter-array cables and offshore export cables during the construction phase in the project alone was expected to be negligible. The impact of the cumulative Tier 2 projects is also expected to be minimal with other projects located further offshore or using the same intermittent and temporary methods of installation.
554. The cumulative impact is predicted to be of local spatial extent, short term duration and intermittent and of high reversibility. The magnitude is therefore, considered to be negligible.

Firth of Forth Banks Complex MPA

555.  A number of the projects in Tier 2 will create an increase in suspended sediment and associated deposition during the Proposed Development construction period which may result in an impact upon the FFBC MPA. Activities contributing to this impact include wind turbine and OSP/Offshore convertor station platform foundation installation, cable installation and maintenance works. One such example is the offshore export cable corridor for Inch Cape which is located to the east of the Proposed Development, beyond the Forth Banks Complex ncMPA. However, it the event that trenching activities be undertaken simultaneously, the sediment plumes would not interact with those from the Proposed Development. Seagreen 1 and Seagreen 1A may have maintenance works within the FFBC MPA during the Proposed Development construction phase which may interact with the plume created by the Proposed Development however the likelihood of a temporal overlap is very low and is unlikely to result effects greater than those assessed for the project alone assessment.
556. The cumulative impact is predicted to be of local spatial extent, short term duration and intermittent and of high reversibility. The magnitude is therefore, considered to be low.

Berwickshire and North Northumberland Coast SAC

557. It is predicted that the impact would not affect the SAC or other receptors as the resultant plumes from offshore cable installation for the Proposed Development and dredge material deposition at the Eyemouth disposal site are unlikely to interact and create a cumulative impact.
558. The cumulative impact is predicted to be of local spatial extent, short term duration and intermittent and of high reversibility. The magnitude is therefore, considered to be negligible.

Sensitivity of receptor

Subtidal Habitat IEFs

559. The sensitivity of the IEFs are as detailed in paragraphs 161 to 170, as well as Table 8.21   Open ▸ .
560. The moderate energy subtidal rock IEF, cobble/stony reef outside of an SAC IEF, and rocky reef outside an SAC IEF is deemed to be of low vulnerability, medium recoverability, and national value. The sensitivity of the IEF is therefore, considered to be medium.
561. The subtidal sand and muddy sand sediments IEF and the subtidal coarse and mixed sediments IEF are deemed to be of low vulnerability, high recoverability, and regional value. The sensitivity of the IEFs is therefore, considered to be low.
562. The seapens and burrowing megafauna IEF and the Sabellaria reef outside of an SAC IEF are deemed to be not sensitive and of national value. The sensitivity of the IEFs is therefore, considered to be negligible.
563. Although there is an impact on PMF(s) this will not create significant impact on the national status of these features because of the negligible to low sensitivity of the IEFs and the limited scale of the impact only noticeably impacting habitats in the immediate vicinity of new infrastructure installation.

Intertidal Habitat IEFs

564. The sensitivity of the IEFs are as detailed in paragraphs 171 to 173, as well as Table 8.21   Open ▸ .
565. The intertidal rock IEF and fucus dominated intertidal rock IEFs are deemed to be of medium vulnerability and medium recovery and national value. The sensitivity of the IEFs is therefore, considered to be medium.
566. The intertidal sands IEF is deemed to be not sensitive and of national value. The sensitivity of the IEF is therefore, considered to be negligible.

Firth of Forth Banks Complex MPA

567. The sensitivity of the IEFs are as detailed in paragraphs 176 to 180, as well as Table 8.22   Open ▸ .
568. The subtidal sands and gravels IEF, and the shelf banks and mounds IEF are deemed to be of low vulnerability, high recoverability, and national value. The sensitivity of the IEFs is therefore, considered to be low.
569. The ocean quahog IEF is deemed to be not sensitive and of national value. The sensitivity of the IEF is therefore, considered to be negligible.

Berwickshire and North Northumberland Coast SAC

570. The sensitivity of the IEFs are as detailed in paragraphs 181 to 189, as well as Table 8.23   Open ▸ .
571. The mudflats and sandflats not covered by seawater at low tide IEF is deemed to be of low vulnerability, high recoverability and international value. The sensitivity of the IEF is therefore, considered to be low.
572. The reefs (subtidal and intertidal rocky reef) IEF is deemed to be of low vulnerability, high recoverability and international value. The sensitivity of the IEF is therefore, considered to be medium.
573. The submerged or partially submerged sea caves IEF is deemed to be of medium vulnerability, medium recoverability and international value. The sensitivity of the IEF is therefore, considered to be medium.
574. The large shallow inlets and bays IEF is deemed to be of low vulnerability, high recoverability and international value. The sensitivity of the IEF is therefore, considered to be low.

Significance of effect

Subtidal Habitat IEFs

575. Overall, for the cobble/stony reef outside of an SAC IEF, the rocky reef outside an SAC IEF and the moderate energy subtidal rock IEF, the magnitude of the impact is deemed to be low and the sensitivity of the receptors is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery for these IEF to this short-term impact.
576. Overall, for the subtidal sand and muddy sand sediments IEF, and the subtidal coarse and mixed sediments IEF, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery for these IEF to this short-term impact.
577. Overall, for the seapens and burrowing megafauna IEF and the Sabellaria reef outside of an SAC IEF, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery for these IEF to this short-term impact. 

Intertidal Habitat IEFs

578. Overall, for the intertidal rock IEF and the fucus dominated intertidal rock IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery for these IEF to this short-term impact.
579. Overall, for the intertidal sands IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery for these IEF to this short-term impact. 

Firth of Forth Banks Complex MPA

580. Overall, for the subtidal sands and gravels IEF, and the shelf banks and mounds IEF, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery for these IEF to this short term impact. 
581. Overall, for the ocean quahog IEF, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery for these IEF to this short term impact. 

Berwickshire and North Northumberland Coast SAC

582. Overall, for the mudflats and sandflats not covered by seawater at low tide SAC IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery from this impact and the large distance between this IEF and any potentially active construction activities.
583. Overall, for the reefs (subtidal and intertidal rocky reef) IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery from this impact and the large distance between this IEF and any potentially active construction activities. 
584. Overall, the submerged or partially submerged sea caves IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery from this impact and the large distance between this IEF and any potentially active construction activities.
585. Overall, for the large shallow inlets and bays IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the high likelihood of recovery from this impact and the large distance between this IEF and any potentially active construction activities. 

Further mitigation and residual effect

586. No benthic subtidal and intertidal ecology mitigation is considered necessary for the impact of increases in SSC and associated sediment deposition during the construction phase because the predicted effects in the absence of further mitigation (beyond the designed in measures outlined in section 8.10), are not significant in EIA terms.

Operation and maintenance phase

Magnitude of impact

Subtidal Habitat IEFs

587. The magnitude of the increase in suspended sediment concentrations and associated deposition arising from maintenance activities, has been assessed as negligible for the Proposed Development alone, as described in section 8.11.
588. The Tier 2 projects outlined in Table 8.34   Open ▸ will all be in their operation and maintenance phases during the operation and maintenance phase of the Proposed Development. Therefore, as previously, maintenance activities associated with these projects may result in increased SSCs, however these activities would be of limited spatial extent and frequency. The cumulative impacts would therefore be of a lesser magnitude than the Tier 2 construction phase assessment (i.e. also negligible).
589. Potential cumulative impacts may relate to maintenance and reburial of the offshore export cables coinciding with the use of the Eyemouth disposal site. Maintenance activities are both intermittent and of smaller scale than the construction phase and therefore any potential cumulative impacts are less likely to occur and be of a smaller scale.
590. The cumulative impact is predicted to be of local spatial extent, short term duration, intermittent and of high reversibility. The magnitude is therefore, considered to be negligible.

Intertidal Habitat IEFs

591. The magnitude of the increase in suspended sediment concentrations and associated deposition arising from the installation of wind turbines and OSP/Offshore convertor station platform foundations, inter-array cables and offshore export cables during the operation and maintenance phase for the Proposed Development alone was predicted to be negligible. The impact of the cumulative Tier 2 projects is also expected to be minimal with other projects located further offshore or using the same intermittent and temporary methods of installation.
592. The cumulative impact is predicted to be of local spatial extent, short term duration and intermittent and of high reversibility. The magnitude is therefore, considered to be negligible.

Firth of Forth Bank Complex MPA

593. It is predicted that the impact from the cumulative projects would result in additional impact upon the FFBC MPA although the overall effect is likely to similar to the Proposed Development.
594. The cumulative impact is predicted to be of local spatial extent, short term duration, intermittent and of high reversibility. The magnitude is therefore, considered to be low.

Berwickshire and North Northumberland Coast SAC

595. It is predicted that the impact would not affect the MPA or other receptors as increased suspended sediments from maintenance activities at the Proposed Development and at the Eyemouth disposal site are likely to be intermittent and on a smaller scale than the construction phase.
596. The cumulative impact is predicted to be of local spatial extent, short term duration, intermittent and of high reversibility. The magnitude is therefore, considered to be negligible.

Sensitivity of the receptor

Subtidal Habitat IEFs

597. The sensitivity of the IEFs are as detailed in paragraphs 161 to 170, as well as Table 8.21   Open ▸ in the project alone assessment, and in paragraphs 561 to 563 of the CEA assessment.

Intertidal Habitat IEFs

598. The sensitivity of the IEFs are as detailed in paragraphs 171 to 173, as well as Table 8.21   Open ▸ in the project alone assessment, and in paragraphs 565 and 566 of the CEA assessment.

Firth of Forth Banks Complex MPA

599. The sensitivity of the IEFs are as detailed in paragraphs 176 to 180, as well as Table 8.22   Open ▸ in the project alone assessment, and in paragraphs 568 and 569 of the CEA assessment.

Berwickshire and North Northumberland Coast SAC

600. The sensitivity of the IEFs are as detailed in paragraphs 181 to 189, as well as Table 8.23   Open ▸ in the project alone assessment, and in paragraphs 571 to 574 of the CEA assessment.

Significance of the effect

Subtidal Habitat IEFs

601. Overall, for the cobble/stony reef outside of an SAC IEF, the rocky reef outside an SAC IEF and the moderate energy subtidal rock IEF, the magnitude of the impact is deemed to be negligible, and the sensitivity of the receptors is considered to be low. The effect will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase.
602. Overall, for the subtidal sand and muddy sand sediments IEF and the subtidal coarse and mixed sediments IEF, the magnitude of the cumulative impact is deemed to be negligible, and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase.
603. Overall, for the seapens and burrowing megafauna IEF and the Sabellaria reef outside of an SAC IEF, the magnitude of the cumulative impact is deemed to be negligible, and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms. 

Intertidal Habitat IEFs

604. Overall, for the intertidal rock IEF and the fucus dominated intertidal rock IEF, the magnitude of the cumulative impact is deemed to be negligible, and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase.
605. Overall, for the intertidal sands IEF, the magnitude of the cumulative impact is deemed to be negligible, and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms. 

Firth of Forth Banks Complex MPA

606. Overall, for the subtidal sands and gravels IEF, and the shelf banks and mounds IEF, the magnitude of the cumulative impact is deemed to be low, and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase. 
607. Overall, for the ocean quahog IEF, the magnitude of the cumulative impact is deemed to be low, and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms. 

Berwickshire and North Northumberland Coast SAC

608. Overall, for the mudflats and sandflats not covered by seawater at low tide SAC IEF, the magnitude of the impact is deemed to be negligible, and the sensitivity of the receptors is considered to be low. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase as well as the large distance between this SAC and the Proposed Development.
609. Overall, for the reefs (subtidal and intertidal rocky reef) IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase as well as the large distance between this SAC and the Proposed Development, which is not significant in EIA terms.
610. Overall, the submerged or partially submerged sea caves IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase as well as the large distance between this SAC and the Proposed Development.
611. Overall, for the large shallow inlets and bays IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms. 

Further mitigation and residual effect

612. No benthic subtidal and intertidal ecology mitigation is considered necessary for the impact of increases in SSC and associated sediment deposition during the construction phase because the likely effects in the absence of further mitigation (beyond the designed in measures outlined in section 8.10), are not significant in EIA terms.

Decommissioning phase

613. As per the maximum design scenario for the Proposed Development, during the decommissioning phase all structures above the seabed would be removed. It is proposed to remove all export, inter-array and inter-connector cables and scour protection where possible and appropriate to do so. During decommissioning cables would be removed by similar processes as undertaken during installation therefore increases in SSC would be of a similar form and magnitude. Following decommissioning, changes in suspended sediments concentration and sedimentation would return to baseline levels as it is anticipated that all structures above the seabed level will be completely removed and no further operation to disturb the seabed would be required. Therefore, the assessment for the construction phase is deemed equally applicable for the decommissioning phase and is not repeated here (see paragraphs 546 to 586).

Tier 3

Construction phase

Magnitude of impact

Subtidal Habitat IEFs

614. During the construction phase of the Proposed Development there is the potential for cumulative impacts with three Tier 3 cable installations. The Cambois connection is a 170 km cable route extending southwards from the Proposed Development array area. Scoping indicates the project will consist of up to four cables installed in 2 m wide trenches up to 3 m in depth. Installation techniques may include jet trenching, cable ploughing and mass flow excavator, as ground conditions dictate. Site preparation will be required, such as boulder and sand wave clearance as part of the approximately two year construction programme.
615. The cumulative impact is predicted to be of local spatial extent, short term duration, intermittent and of high reversibility. The magnitude is therefore, considered to be low.

Intertidal Habitat IEFs

616. The installation parameters, described in paragraph 613, are similar to those of the Proposed Development and therefore the magnitude of the impact on the coastal receptors this would be negligible. The other projects described in this tier are unlikely to affect the intertidal habitats.
617. The cumulative impact is predicted to be of local spatial extent, short term duration, intermittent and of high reversibility. The magnitude is therefore, considered to be negligible.

Firth of Forth Banks Complex MPA

618. The Cambois connection export cable route extending southwards from the Proposed Development array area will directly impact the Firth of Forth Banks Complex MPA, however the scoping report does not provide detail on the potential increase in suspended sediment and associated deposition. It can be assumed that the impact will likely be similar to the installation of the offshore export cables and is unlikely to result in a cumulative impact greater than the project alone assessment.
619. The cumulative impact is predicted to be of local spatial extent, short term duration and intermittent and of high reversibility. The magnitude is therefore, considered to be low.

Berwickshire and North Northumberland Coast SAC

620. As a coastal SAC the magnitude as discussed in paragraph 616 is applicable and therefore the cumulative impact is predicted to be of local spatial extent, short term duration and intermittent and of high reversibility. The magnitude is therefore, considered to be negligible.

Sensitivity of the receptor

Subtidal Habitat IEFs

621. The sensitivity of the IEFs are as detailed in paragraphs 161 to 170, as well as Table 8.21   Open ▸ in the project alone assessment, and in paragraphs 561 to 563 of the CEA assessment.

Intertidal Habitat IEFs

622. The sensitivity of the IEFs are as detailed in paragraphs 171 to 173, as well as Table 8.21   Open ▸ in the project alone assessment, and in paragraphs 565 and 566 of the CEA assessment.

Firth of Forth Banks Complex MPA

623. The sensitivity of the IEFs are as detailed in paragraphs 176 to 180, as well as Table 8.22   Open ▸ in the project alone assessment, and in paragraphs 568 and 569 of the CEA assessment.

Berwickshire and North Northumberland Coast SAC

624. The sensitivity of the IEFs are as detailed in paragraphs 181 to 189, as well as Table 8.23   Open ▸ in the project alone assessment, and in paragraphs 571 to 574 of the CEA assessment.

Significance of the effect

Subtidal Habitat IEFs

625. Overall, for the cobble/stony reef outside of an SAC IEF, the rocky reef outside a SAC IEF and the moderate energy subtidal rock IEF, the magnitude of the impact is deemed to be low, and the sensitivity of the receptors is considered to be medium. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase.
626. Overall, for the subtidal sand and muddy sand sediments IEF, and the subtidal coarse and mixed sediments IEF, the magnitude of the cumulative impact is deemed to be low, and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase.
627. Overall, for the seapens and burrowing megafauna IEF and the Sabellaria reef outside of an SAC IEF, the magnitude of the cumulative impact is deemed to be low, and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase. 

Intertidal Habitat IEFs

628. Overall, for the intertidal rock IEF and the fucus dominated intertidal rock IEF, the magnitude of the cumulative impact is deemed to be negligible, and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase.
629. Overall, for the intertidal sands IEF, the magnitude of the cumulative impact is deemed to be negligible, and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms. 

Firth of Forth Banks Complex MPA

630. Overall, for the subtidal sands and gravels IEF, and the shelf banks and mounds IEF, the magnitude of the cumulative impact is deemed to be low, and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms. 
631. Overall, for the ocean quahog IEF, the magnitude of the cumulative impact is deemed to be negligible, and the sensitivity of the receptor is considered to be negligible. The cumulative impact will, therefore, be of minor adverse significance, which is not significant in EIA terms. 

Berwickshire and North Northumberland Coast SAC

632. Overall, for the mudflats and sandflats not covered by seawater at low tide SAC IEF, the magnitude of the cumulative impact is deemed to be negligible, and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms, because of the very small magnitude and intermittent nature of this impact in this phase as well as the large distance between this SAC and the Proposed Development.
633. Overall, for the reefs (subtidal and intertidal rocky reef) IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms. 
634. Overall, the submerged or partially submerged sea caves IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms.
635. Overall, for the large shallow inlets and bays IEF, the magnitude of the cumulative impact is deemed to be negligible and the sensitivity of the receptor is considered to be low. The cumulative impact will, therefore, be of negligible adverse significance, which is not significant in EIA terms. 

Further mitigation and residual effect

636. No benthic subtidal and intertidal ecology mitigation is considered necessary for the impact of increases in SSC and associated sediment deposition during the construction phase because the likely effects in the absence of further mitigation (beyond the designed in measures outlined in section 8.10), are not significant in EIA terms.