Decommissioning phase
  1. Increases in SSC and associated sediment deposition may occur during the decommissioning phase as a result of the cutting and removal of wind turbines/OSP-Offshore convertor station platform foundations and the removal of inter-array, interconnector, and offshore export cables (although this will be informed by best practice and guidance at the time). Full details on the project envelope assumptions and maximum design scenario with respect to foundation and cable decommissioning are provided section 1.4.
  2. The potential impact of increased SSC and the associated deposition have not been modelled specifically in volume 2, chapter 7 of the Offshore EIA Report, the activities involved in decommissioning are expected to result in increase in SSC and associated deposition of a similar or lower level of effect as the construction phase.

Offshore subtidal sands and gravels/shelf banks and mounds

  1. The level of impacts on the physical and ecological attributes of the offshore subtidal sands and gravels feature and the shelf banks and mounds feature in the decommissioning phase is similar to that which is predicted during the construction phase (for offshore subtidal sands and gravels see paragraphs 277 to 282, and for shelf banks and mounds see paragraphs 284 to 283). This assessment predicted that due to the low levels of SSC and deposition, the limited extent of the highest levels of SSC and deposition as well as the temporary and intermittent nature of the impact and the tolerance of the characteristic community the sensitivity of the physical and ecological attributes would be low. As discussed in paragraph 287 for offshore subtidal sands and gravels and in paragraph 281 for shelf banks and mounds, with respect to the conservation objectives of these protected features, it can be concluded that wind turbines foundation and cable removal leading to increases in SSC and associated deposition will not result in a significant risk of hindering the achievement of the conservation objectives set out in paragraphs 175 and 176.

Long Term Subtidal Habitat Loss

Construction and operation and maintenance phase
  1. Long term subtidal habitat loss may occur within the Firth of Forth Banks Complex MPA during the construction phase, as infrastructure is gradually installed, and will extend into the operation and maintenance phase due to the presence of foundations (from wind turbines and OSPs/Offshore convertor station platforms). There may also be long term habitat alteration within the MPA as a result of the installation of cable protection for cables and cable crossings. Where there is the potential for structures such as cable and scour protection to be colonised over time during the projects lifetime this has been referred to as habitat alteration. As ocean quahog however cannot colonise this habitat cable and scour protection are referred to habitat loss for the assessment of this feature. Table 1.42   Open ▸ presents the maximum design scenario for long term habitat loss and habitat alteration within the Firth of Forth Banks Complex MPA. The maximum design scenario assumes long term habitat loss associated with suction caisson jacket foundations for the larger scenario wind turbines and suction caisson jacket foundations OSPs/Offshore convertor station platforms. Full details of why the suction caisson jacket foundations and the larger wind turbines represent the maximum design scenario are presented in annex A.
  2. This assessment is equivalent to the following pressure identified by JNCC's Advice on Operations for the Firth of Forth Banks Complex MPA for ‘Renewable Energy: offshore wind’ and ‘Power cables: laying burial and protection’ (JNCC, 2018c):
  • Physical change to another seabed type.

 

Table 1.42:
Maximum Design Scenario for Long Term Habitat Loss/Alteration within Firth of Forth Banks Complex MPA

Table 1.42: Maximum Design Scenario for Long Term Habitat Loss/Alteration within Firth of Forth Banks Complex MPA

1 For the purposes of replicating the calculations in this table, 31.33% is calculated as 316.5 km2/1010.2 km2 (i.e. overlap between Proposed Development array area / total Proposed Development array area).

2 For the purposes of replicating the calculations in this table, 13.08% is calculated as 114.08 km/872 km (i.e. proportion of total length of offshore export cables that could occur within the part of the Proposed Development export cable corridor that overlaps with the MPA).

 

  1. On the basis of the assumptions outlined in paragraph 189, there may be up to 1.96 km2 of long term habitat loss within the Firth of Forth Banks Complex MPA during the construction phase and operation and maintenance phase, equating to 0.09% of the total area of the MPA. Of this total, up to 0.61 km2 may occur within the Scalp and Wee Bankie section (0.03% of the total area of the MPA and 0.07% of the Scalp and Wee Bankie component) and up to 1.36 km2 within the Berwick Bank section of the MPA (0.06% of the total area of the MPA and 0.25% of the Berwick Bank component); see Table 1.43   Open ▸ . An indicative layout of the wind turbines within the MPA is included in Figure 1.15, however this has not been used to determine the proportion of long term habitat loss that will occur in each section of the MPA as it is not finalised.

 

Table 1.43:
Summary of the Extent of Long Term Habitat Loss/Alteration within the Firth of Forth Banks Complex MPA (as a Whole, and for the Component Sites) During the Construction and Operation and Maintenance Phase

Table 1.43: Summary of the Extent of Long Term Habitat Loss/Alteration within the Firth of Forth Banks Complex MPA (as a Whole, and for the Component Sites) During the Construction and Operation and Maintenance Phase

1Calculated as 30.81% of the 1.96 km2 total on the basis of the overlap with the Scalp and Wee Bankie (see paragraph 170).

2 Calculated as 69.19% of the 1.96 km2 total on the basis of the overlap with the Berwick Bank (see paragraph 188).

3 Calculated as 43.82% of total 0.61 km2 of disturbance within the Scalp and Wee Bankie section (i.e. 43.82% of the total area of Scalp and Wee Bankie that overlaps with the Proposed Development and contains the shelf banks and mounds feature).

4 Calculated as 8.64% of total 1.36 km2 of disturbance within the Berwick Bank section (i.e. 8.64% of the total area of Berwick Bank that overlaps with the Proposed Development and contains the shelf banks and mounds feature).

5 Calculated as 71.59% of total 0.61 km2 of disturbance within the Scalp and Wee Bankie section (i.e.71.59% of the total area of Scalp and Wee Bankie that overlaps with the Proposed Development and contains the moraines feature).

6 Calculated as 0.16% of total 1.36 km2 of disturbance within the Berwick Bank section (i.e. 0.16% of the total area of Berwick Bank that overlaps with the Proposed Development and contains the moraines feature).



Offshore subtidal sands and gravels

  1. On the basis of the assumptions outlined in paragraph 190, and for the purposes of this assessment, it is assumed that all of the potential long term habitat loss (associated with the presence of wind turbine/OSP-Offshore convertor station platform foundations and scour protection) and long term habitat alteration (associated with cable protection for cables and cable crossings) will occur within this feature ( Table 1.42   Open ▸ ). This equates to 1.96 km2 and 0.09% of the total extent of the offshore subtidal sands and gravels feature. Of this 0.61 km2 will occur within Scalp and Wee Bankie (0.03% of the area of this feature in the MPA) and 1.36 km2 in the Berwick Bank part of the MPA (0.06% of the area of this feature in the MPA); see Table 1.43   Open ▸ .
  2. The installation of infrastructure resulting in long term habitat loss and habitat alteration will commence during the 96 month construction phase and will continue for the full 35 year operation and maintenance phase.
  3. The biotopes identified in association with the offshore subtidal sands and gravel feature, as described previously in paragraphs 203 and 204, have a high sensitivity to the pressure of ‘physical change to another substratum’. As these biotopes are typically characterised by infaunal species the physical change to another substrate type, i.e. the hard surface of foundations and cable protection for cables and cable crossings, would not allow for the continued presence of these communities at those locations, therefore they are highly intolerant of changes to new substrate. The long term habitat loss and alteration, however, represents only 0.09% of the Firth of Forth Banks Complex MPA therefore the impact on this feature within the regional ecosystem will be small, representing a highly localised change in community.
  4. Based on the information presented above, the following can be concluded with respect to the physical attributes of the offshore subtidal sands and gravels feature of the Firth of Forth Banks Complex MPA:
  • The extent and distribution of offshore subtidal sands and gravels feature will be largely maintained within the MPA. While the Proposed Development is predicted to result in long term habitat loss and alteration of a very small proportion of the protected feature (i.e. up to 0.09% of the offshore subtidal sands and gravels feature; see Table 1.43   Open ▸ ), the effect will be highly localised to discrete areas within the MPA. The majority will be habitat alteration associated with cable protection for cables and cable crossings which represents a shift in substrate type rather than a total loss of habitat. It can be assumed that epifaunal communities will in time colonise these areas, potentially providing some recovery of communities in areas where cable protection for cables and cable crossings is placed and reducing the extent of long term habitat loss in the MPA. This is consistent with the ‘conserve’ objective of the extent and distribution attribute for this feature.
  • The hydrodynamic regime is key to a number of the physical and biological attributes of this feature, the long term loss or alteration of habitat will not be a contributor to any change in the prevailing regime as the change is of such a limited impact. Sediment transport may be minorly altered with changes in residual current and sediment transport of approximately ±15% which is largely sited within close proximity to the wind turbine foundation structures, however this is considered unlikely to impact upon this large-scale feature as the effects will be highly localised. This is consistent with the ‘conserve’ objective of the supporting processes attribute for this feature.
  • The fine scale topographic features within this habitat will be minimally impacted by the long term habitat loss and alteration as they rely on supporting processes such as sediment transport enabled by the prevailing hydrodynamic regime which, as discussed above, will remain predominantly unchanged as a result of long term habitat loss and alteration. Any minor changes to substrate availability or hydrodynamic regime may impact on sand ripples but on a small scale. The larger banks and mounds feature is too large to be impacted by changes of this magnitude (see paragraphs 272 to 275 and 397 for more detail). This is consistent with the ‘recover’ objective of the structure and function attribute for this feature.
  • The sediment composition of this site involves a range of substrate, the loss and alteration of this substrate in 0.09% of the MPA area is unlikely to result in a change to the sediment composition of this large scale feature, especially as the hydrodynamic regime which enables sediment transport into this feature remains functional. The seabed infrastructure will be deployed in discrete areas with only a localised effect on sediment transport but unlikely to result in changes to sediment composition. This is consistent with the ‘recover’ objective of the structure and function attribute for this feature.
    1. The following can be concluded with respect to the ecological attributes of the offshore subtidal sands and gravels feature of the Firth of Forth Banks Complex MPA:
  • The key and influential species of this protected feature will be minimally impacted by the loss of a small proportion of their habitat and are likely to maintain their populations throughout the construction and operation and maintenance phases of the Proposed Development. The majority of the (i.e. >99%) of this protected feature within the Firth of Forth Banks Complex MPA will be unaffected by long term habitat loss or alteration. This is consistent with the ‘recover’ objective of the structure and function attribute for this feature.
  • The characteristic communities associated with this feature will, overall, be maintained following the placement of infrastructure, as only a small proportion of this habitat (0.09%) will be affected in discrete locations. Due to these localised impacts and the wide extent of this feature, the characteristic communities are likely to be maintained throughout the feature. This is consistent with the ‘recover’ objective of the structure and function attribute for this feature.
  • The function of the feature depends upon a combination of a number of the attributes discussed above (paragraphs 297 and 298). The biological productivity of this feature will not be disturbed as it is controlled by the upwelling currents which are a part of the hydrodynamic regime which will be unaffected by long term habitat loss and habitat alteration. The small scale and localised nature of the impact (0.09% of total area of this feature) will enable the feature to retain its function as it pertains to climate regulation. Applying these effects to the features function as a spawning ground and feeding ground for commercial species, volume 2, chapter 9 of the Offshore EIA Report found sandeels to be the most sensitive any long term habitat loss due to their preference for sandy habitats and laying their eggs on the seabed. However, monitoring at Horns Rev I, located off the Danish coast, has indicated that the presence of operational wind farm structures has not led to significant adverse effects on sandeel populations in the long term (van Deurs et al., 2012; Stenberg et al., 2011). Initial results of a pre to post-construction monitoring study have reported that in some areas of the Beatrice Offshore Wind Farm, there was an increase in sandeel abundance (BOWL, 2021). These studies provide encouraging evidence to support the conservancy of this function across the feature. Volume 2, chapter 9 of the Offshore EIA Report also discusses monitoring from a Belgian offshore wind farm which reported that fish assemblages do not experience drastic changes due to the presence of offshore wind farms (Degraer et al., 2020). This is consistent with the ‘recover’ objective of the structure and function attribute for this feature.
    1. Volume 2, chapter 8 of the Offshore EIA Report concluded that due to the limited extent of the impact of long term habitat loss and alteration, and the relatively small proportion of the protected features to be affected during operation and maintenance, the magnitude of the impact on the features of the Firth of Forth Banks Complex MPA was low. The offshore subtidal sands and gravels protected feature of the Firth of Forth Banks Complex MPA is considered to be of high vulnerability, low recoverability and national importance and therefore was considered to have a high sensitivity. Therefore, the significance of effect was considered to be minor adverse.
    2. Based on the information presented here, it can be concluded that long term habitat loss and habitat alteration during the Proposed Development construction and operation and maintenance phase will not lead to a significant risk of hindering the achievement of the overall conservation objective for the offshore subtidal sands and gravels (i.e. “recover to favourable condition”) feature of the Firth of Forth Banks Complex MPA for the following reasons:
  • Long term habitat loss and habitat alteration is predicted to affect a very small proportion of the habitat feature (0.09%) over the duration of the construction and operation and maintenance phase. This feature will, therefore, maintain its extent, and distribution; and
  • The structures and functions, quality, and the composition of characteristic communities will remain in (or recover to) a condition which is healthy and not deteriorating. Only a small proportion of the overall habitat will become unavailable to the characteristic communities. The key and influential species are predicted to recolonise the areas around the new infrastructure, with full recovery of characteristic communities following the decommissioning of some infrastructures. These communities will be supported by an undisturbed hydrodynamic regime which will continue to form the fine scale features of the MPA.

Shelf banks and mounds

  1. On the basis of the assumptions outlined in paragraph 191, and for the purposes of this assessment, it is assumed that 19.48% of the maximum long term habitat loss and habitat alteration associated with the Proposed Development within the MPA could occur in this feature. This would result in a maximum of 0.38 km2 of long term habitat loss/alteration within the Firth of Forth Banks Complex MPA (this impact can be divided by activity, the figures for which are in Table 1.43   Open ▸ ). This would equate to this long term habitat loss and alteration of up to 0.14% of the total extent of this protected feature within the MPA. Of this, up to 0.27 km2 may occur within Scalp and Wee Bankie (0.10% of the total area of the feature in the MPA) and up to 0.12 km2 may occur within the Berwick Bank section of the MPA (0.04% of the total area of the feature in the MPA) (see Table 1.43   Open ▸ ).
  2. The duration of the habitat loss and alteration is detailed in paragraph 295 and the biotopes and their sensitivity are the same as for the offshore subtidal sand and gravel feature (paragraph 296).
  3. Based on the information presented above, the following can be concluded with respect to the physical and biological attributes of the protected features of the Firth of Forth Banks Complex MPA:
  • The extent and distribution of the shelf banks and mounds feature would be largely maintained as only a very small proportion of the total extent of this feature will be affected by long term habitat loss and alteration (0.14%), preserving the majority of the feature. This is consistent with the ‘conserve’ objective of the extent and distribution attribute for this feature.
  • The hydrodynamic regime of this area is not expected to be disrupted by long term habitat loss and alteration within this feature, enabling the sediment transport which forms these features to continue throughout the operation and maintenance phase of the Proposed Development, maintaining the supporting processes. Volume 2, chapter 7 of the Offshore EIA Report modelled changes to tidal and wave conditions of 2% at peak flow and <1% of wave height. Sediment transport may be minorly altered with changes in residual current and sediment transport of approximately ±15% which is largely sited within close proximity to the wind turbine foundation structures, however this is considered unlikely to impact upon this large-scale feature as the effects will be highly localised. This is consistent with the ‘conserve’ objective of the structure and function attribute for this feature.
  • The physical nature of this protected feature formed by the hydrodynamic regime and sediment transport processes of the wider environment and as noted above neither the extent not supporting processes will experience major deterioration due to long term habitat loss and alteration. Instead, the minimal area of long term habitat loss/alteration and minimal disturbance of the hydrodynamic regime will enable the maintenance of the physical nature of the protected feature. This is consistent with the ‘conserve’ objective of the supporting processes attribute for this feature.
    1. Volume 2, chapter 8 of the Offshore EIA Report concluded that due to the limited extent of the impact of long term habitat loss and alteration, and the minor proportion of the protected features to be affected during operation and maintenance, the magnitude of the impact on the features of the Firth of Forth Banks Complex MPA was low. The shelf banks and mounds protected feature of the Firth of Forth Banks Complex MPA is considered to be of high vulnerability, low recoverability and national importance and therefore was considered to have a high sensitivity. Therefore, the significance of effect was considered to be minor.
    2. Based on the information presented here, it can be concluded that long term habitat loss and habitat alteration during the construction and operation and maintenance phases will not lead to a significant risk of hindering the achievement of the overall conservation objective for this feature of the Firth of Forth Banks Complex MPA (i.e. “maintain in favourable condition”) for the following reasons:
  • Long term habitat loss and alteration is predicted to affect a very small proportion (0.14%) of the habitat feature over the duration of the construction phase within the MPA during the operation and maintenance phase. Therefore, the extent and distribution of the protected feature will be maintained;
  • The function will remain in a condition which is healthy and not deteriorating due to the limited extent of habitat loss and alteration. This will ensure that the feature continues to support its characteristic biological communities and their use of the site for feeding, courtship, spawning, or use as nursery ground; and
  • The supporting processes which enable the formation of these large features and create the necessary environmental conditions to enable its structure and function will be maintained.

Ocean quahog aggregations

  1. On the basis of the assumptions outlined in paragraph 190, and for the purposes of this assessment, it is assumed that all of the potential long term habitat loss occurring within the MPA (i.e. 1.96 km2) may occur within supporting habitat for ocean quahog aggregations (see Table 1.43   Open ▸ ) which would equate to a loss of 0.09% of supporting habitat for this protected feature within the MPA.
  2. The infrastructure resulting in long term habitat loss will be installed in the construction phase and remain present for the full 35 year operation and maintenance phase.
  3. The ocean quahog aggregations protected feature is expected to have a high sensitivity to physical change to another substratum. This is because they rely upon their sedimentary habitat for feeding as suspension/deposit feeders as well as shelter from predators and high energy currents by burrowing. Ocean quahogs would be intolerant of replacing this habitat with hard structure (Tyler-Walter and Sabatini, 2017).
  4. The installation of the infrastructure associated with the Proposed Development may, however, have some beneficial effects on ocean quahog, As discussed in paragraph 221, there will be no safety zones enforced during the operation and maintenance phase (except during maintenance events), however a 50 m safe passing distance for logistical and safety reasons (i.e. to account for the offset/drifting of fishing gear that happens as a result of the tide) can be assumed for fishing vessels in the vicinity of wind turbines. As a result, ocean quahog in the vicinity of the offshore infrastructure may potentially experience a reduced level of disturbance from commercial fishing in the long term (i.e. over the operational lifetime of the Proposed Development and potentially beyond), which may aid with the recovery of the wider population to the impact of habitat loss.
  5. Based on the information presented above, the following can be concluded with respect to the physical and biological attributes of the protected features of the Firth of Forth Banks Complex MPA:
  • The extent and distribution of ocean quahog aggregations largely be maintained despite the loss of a very small portion of supporting habitat (0.09%) within the entire MPA. This will minimise as far possible the change in substrate type across the MPA. Beyond this initial loss of habitat, ocean quahog aggregations will still be provided with a stable environment in which to feed and reproduce with no major ongoing disturbance from the infrastructure. This is consistent with the ‘conserve’ objective of the extent and distribution attribute for this feature.
  • The structure of the ocean quahog aggregations is dependent on the continued ability of ocean quahogs to reproduce at the site. The small proportion of habitat loss will not result in any long term impacts upon ocean quahogs to reproduce in the area as >99% of suitable habitat will be maintained. Furthermore, as noted in paragraph 309, a likely reduction in fishing pressure in the immediate vicinity of the wind turbines will likely aid the recovery of the ocean quahog population within the MPA. This is consistent with the ‘conserve’ objective of the structure and function attribute for this feature.
  • The long term loss of habitat will not change the prevailing hydrodynamic conditions of the site however it may cause a localised change in sediment transport and a very small change to wave and tidal conditions (paragraphs 297 and 303), the limited scale of these changes is unlikely to compromise the conditions which ocean quahog rely upon. This is consistent with the ‘conserve’ objective of the supporting processes attribute for this feature.
  • The continued availability of suitable habitat due to limited long term habitat loss, as well as minimal disturbance to its supporting processes will maintain the habitats which support ocean quahog aggregations. This is consistent with the ‘conserve’ objective of the structure and function attribute for this feature.
  • While there is no evidence of the function that ocean quahog aggregations provide there are a number of potential examples to consider (JNCC, 2018b). The maintenance of the population structure and extent within the MPA contributes to the food web providing food for a number of fish and invertebrate species as well as providing a link for the recycling of nutrients between the pelagic and benthic environments. The highly limited extent of the impact also prevents damage to the features function as a carbon store by ensuring the majority of sediment is undisturbed. Overall, by maintaining the population throughout the MPA through minimal habitat loss ocean quahogs can continue to be studied in relation to historical environmental change and pollution. This is consistent with the ‘conserve’ objective of the structure and function attribute for this feature.
    1. Volume 2, chapter 8 of the Offshore EIA Report concluded that due to the limited nature of the impact of long term habitat loss, and the minor proportion of the protected features to be affected during operation and maintenance, the magnitude of the impact on the features of the Firth of Forth Banks Complex MPA was low. The ocean quahog protected feature of the Firth of Forth Banks Complex MPA is considered to be of high vulnerability, low recoverability and national importance and therefore was considered to have a high sensitivity. Therefore, the significance of effect was considered to be of minor adverse significance.
    2. Based on the information presented here, it can be concluded that long term habitat loss/habitat alteration during the construction and operation and maintenance phases will not lead to a significant risk of hindering the achievement of the overall conservation objective for this feature of the Firth of Forth Banks Complex MPA (i.e. “recover to favourable condition”) for the following reasons:
  • Long term habitat loss is predicted to affect a very small proportion (0.09%) of supporting habitat for ocean quahog during the operation and maintenance phase, but the quality and quantity of ocean quahog habitat will be maintained. Whilst some ocean quahog individuals may be directly affected by the loss of habitat, this is predicted to be to an extent that will not affect the composition of its population in terms of number, age and sex ratio or its ability to thrive in the future and a likely reduction in fishing pressure in the immediate vicinity of the wind turbines will potentially aid the recovery of the ocean quahog population within the MPA.

Wee Bankie key geodiversity area (moraines)

  1. On the basis of the assumptions outlined in paragraph 192, and for the purposes of this assessment, it is assumed that 22.17% of the maximum long term habitat loss/habitat alteration predicted to occur within the MPA could occur in this feature. This equates to a maximum of 0.44 km2 of long term habitat loss within the Wee Bankie Key Geodiversity Area, or 0.06% of the total area of this feature within the MPA. Of this, up to 0.43 km2 may occur within Scalp and Wee Bankie (0.0575% of the total area of this feature within the MPA) and up to 0.002 km2 may occur within the Berwick Bank part of the MPA (0.0003% of the total area of this feature within the MPA) (see Table 1.43   Open ▸ ).
  2. Based on the information presented above, the following can be concluded with respect to the physical and biological attributes of the Wee Bankie Key Geodiversity Area feature of the Firth of Forth Banks Complex MPA:
  • The extent and distribution of the Wee Bankie Key Geodiversity Area (Moraines) feature will be largely maintained throughout the operation and maintenance phase through the preservation of >99% of the protected feature. A very small proportion (0.06%) of the feature may experience long term habitat loss and alteration as a result of cable protection for cables and cable crossings and wind turbines/OSP-Offshore convertor station platform foundations however these areas will be discrete and localised and not impact on the overall large-scale distribution of the feature. This is consistent with the ‘conserve’ objective of the extent and distribution attribute for this feature.
  • The structure of the protected feature was determined during the last glaciation and resulted in the moraines extending ~20 m above the surrounding seabed, with a width of ~20 km and a length of ~70 km. The highly limited extent of habitat loss and alteration within this feature (0.06%) will result in a near negligible impact on its structure. This is consistent with the ‘conserve’ objective of the structure and function attribute for this feature.
  • The function of the moraines lies in their scientific study and the habitat they provide. The limited extent of habitat loss and alteration will not result in structural or extent change enabling scientific study of this feature to continue through the operation and maintenance phase. Additionally, the introduction of wind turbine/OSP-Offshore convertor station platform foundations and scour/cable protection for foundations, cables and cable crossings will not result in large scale changes to the structural composition of the sand and gravel-based feature, and it will still be able to complete its function as a habitat to sedimentary communities. This is consistent with the ‘conserve’ objective of the structure and function attribute for this feature.
    1. Based on the information presented here, it can be concluded that long term habitat loss/alteration during the construction and operation and maintenance phases will not lead to a significant risk of hindering the achievement of the overall conservation objective for the Wee Bankie Key Geodiversity Area feature of the Firth of Forth Banks Complex MPA (i.e. “maintain in favourable condition”) for the following reasons:
  • Long term habitat loss and alteration is predicted to affect a very small proportion (0.06%) of the protected feature during the operation and maintenance phase. Overall, the extent, component elements and integrity as a relict feature within the MPA will be maintained;
  • The structure and function will remain unimpaired by the activities as only a small proportion of the feature will be affected by the long term habitat loss and alteration impact; and
  • The surface of the feature will remain sufficiently unobscured due to the limited extent of the impact as a proportion of the overall feature within the MPA.
Decommissioning phase

The maximum design scenario for permanent habitat alteration during the Proposed Development decommissioning phase assumes that all offshore infrastructure will be removed except for scour protection and some cable protection for cables and cable crossings, which, it is assumed for the purposes of this assessment, will be left in situ. Cable protection for cables and cable crossings and scour protection will be fully removed where it is possible and appropriate to do so noting this will depend on the type of protection used and condition of the protection at the time of removal. Cables will be removed where it is possible and appropriate to do so. As it is difficult to determine the proportion of cable protection for cables and cable crossings which will be removed it has been assumed as a maximum design scenario that all cable protection for cables and cable crossings will remain in situ. The Applicant will however continue to discuss the need for, and feasibility of, the removal of scour and cable protection for cables and cable crossings in sensitive areas such as the MPA as the Proposed Development progresses, with any final plans taking account of best practice at the time of decommissioning. Assessments will be updated accordingly to take account of any such discussions ahead of the final application. Table 1.46   Open ▸ presents the maximum design scenario for long term habitat loss and habitat alteration within the Firth of Forth Banks Complex MPA.

Table 1.44:
Maximum Design Scenario for Permanent Habitat Alteration within Firth of Forth Banks Complex MPA Post Decommissioning

Table 1.44: Maximum Design Scenario for Permanent Habitat Alteration within Firth of Forth Banks Complex MPA Post Decommissioning

1 For the purposes of replicating the calculations in this table, 31.33% is calculated as 316.5 km2/1010.2 km2 (i.e. overlap between Proposed Development array area / total Proposed Development array area).

2 For the purposes of replicating the calculations in this table, 13.08% is calculated as 114.08 km/872 km (i.e. proportion of total length of offshore export cables that could occur within the part of the Proposed Development export cable corridor that overlaps with the MPA).

 

  1. On the basis of the assumptions outlined in paragraph 189, there may be up to 1.89 km2 of permanent habitat alteration within the Firth of Forth Banks Complex MPA following the decommissioning phase, equating to 0.09% of the total area of the MPA. Of this total, up to 0.58 km2 may occur within the Scalp and Wee Bankie section (0.03% of its total area of the MPA or 0.07% of the area of Scalp and Wee Bankie) and up to 1.31 km2 within the Berwick Bank part of the MPA (0.06% of its total area of the MPA or 0.24% of the area of Berwick Bank); see Table 1.45   Open ▸ .

 

Table 1.45:
Summary of the Extent of Permanent Habitat Alteration within the Firth of Forth Banks Complex MPA (as a Whole, and for the Component Sites) Following the Decommissioning Phase

Table 1.45: Summary of the Extent of Permanent Habitat Alteration within the Firth of Forth Banks Complex MPA (as a Whole, and for the Component Sites) Following the Decommissioning Phase

1 Calculated as 30.81% of the 1.89 km2 total on the basis of the overlap with the Scalp and Wee Bankie (see paragraph 170).

2 Calculated as 69.19% of the 1.89 km2 total on the basis of the overlap with the Berwick Bank (see paragraph 188).

3 Calculated as 43.82% of total 0.58 km2 of disturbance within the Scalp and Wee Bankie section (i.e. 43.82% of the total area of Scalp and Wee Bankie that overlaps with the Proposed Development and contains the shelf banks and mounds feature).

4 Calculated as 8.64% of total 1.31 km2 of disturbance within the Berwick Bank section (i.e. 8.64% of the total area of Berwick Bank that overlaps with the Proposed Development and contains the shelf banks and mounds feature).

5 Calculated as 71.59% of total 0.58 km2 of disturbance within the Scalp and Wee Bankie section (i.e.71.59% of the total area of Scalp and Wee Bankie that overlaps with the Proposed Development and contains the moraines feature).

6 Calculated as 0.16% of total 1.31 km2 of disturbance within the Berwick Bank section (i.e. 0.16% of the total area of Berwick Bank that overlaps with the Proposed Development and contains the moraines feature).

 

Offshore subtidal sands and gravels

  1. On the basis of the assumptions outlined in paragraph 190, and for the purposes of this assessment, it is assumed that up to 1.89 km2 of permanent habitat alteration may persist within the offshore subtidal sands and gravels feature of the Firth of Forth Banks Complex MPA following the decommissioning phase. This equates to 0.09% of the total area of this feature within the Firth of Forth Banks Complex MPA. Of the total area of seabed which will be affected, up to 0.58 km2 may be within Scalp and Wee Bankie (0.03% of the total area of the feature within the MPA) and up to 1.31 km2 will occur within the Berwick Bank part of the MPA (0.06% of the total area of the feature within the MPA) (see Table 1.45   Open ▸ ).
  2. An assessment of the impact of long-term habitat loss for this protected feature is presented in paragraph 297. This assessment is directly applicable to the decommissioning phase of the Proposed Development. In the decommissioning phase however, there will be a reduction the total area of habitat loss compared to the operation and maintenance phase (as foundations will be removed) which will reduce the extent of the impact on this feature, with some habitat recovering where infrastructure was removed. Furthermore, it can be assumed that epifaunal communities will in time colonise the cable and scour protection, potentially providing some recovery of communities in areas where cable protection for cables and cable crossings is placed and reducing the extent of permanent habitat alteration in the MPA.
  3. Additionally, the impact on the hydrodynamic regime in the decommissioning phase was modelled in volume 2, chapter 7 of the Offshore EIA Report and was found to have a reduced magnitude compared to the operational and maintenance phase as there will be no structures remaining in the water column after the removal of wind turbines/OSP-Offshore convertor station platform foundations. Overall, the chapter found the impact of the infrastructure on the wave and tidal currents to be negligible, resulting in the no change to the hydrodynamic regime from the pre-construction baseline in the long term/permanent basis in relation to permanent habitat alteration, which helps to conserve other elements such as supporting processes, function, and distribution of features.
  4. Volume 2, chapter 8 of the Offshore EIA Report concluded that due to the limited extent of the impact of permanent habitat alteration following decommissioning, and the relatively small proportion of the protected features to be affected during decommissioning, the magnitude of the impact on the features of the Firth of Forth Banks Complex MPA was low. The offshore subtidal sands and gravels protected feature of the Firth of Forth Banks Complex MPA is considered to be of high vulnerability, low recoverability and national importance and therefore was considered to have a high sensitivity. Therefore, the significance of effect was considered to be minor adverse significance.
  5. Based on the information presented here, it can be concluded that permanent habitat alteration as a result of the cable and scour protection remaining in situ following decommissioning will not lead to a significant risk of hindering the achievement of the conservation objectives for this feature of the Firth of Forth Banks Complex MPA for the reasons detailed in paragraph 300. Principally the overall extent and integrity of the feature will not be hindered as a result of this impact allowing for the unimpaired study of the feature.

Shelf banks and mounds

  1. On the basis of the assumptions outlined in paragraph 191, and for the purposes of this assessment, it is assumed that 19.48% of the maximum permanent habitat alteration within the MPA could occur in this feature. This would result in a maximum of 0.37 km2 of permanent habitat alteration within this feature which equates to 0.14% of the total area of the shelf banks and mounds feature within the MPA. Of this, up to 0.26 km2 may occur within Scalp and Wee Bankie (0.10% of the total area of the feature within the MPA) and up to 0.11 km2 may occur within the Berwick Bank section of the MPA (0.04% of the total area of the feature within the MPA) (see Table 1.45   Open ▸ ).
  2. An assessment of the impact of permanent habitat alteration for this protected feature during the operation and maintenance phase is presented in paragraphs 294 to 302. The differences between the decommissioning phase and the operational phase are described in paragraph 318. The reduced area of the impact, and potential for recovery where infrastructure was removed, and the associated negligible impact on the hydrodynamic regime both will contribute to the conservation of this protected feature.
  3. Volume 2, chapter 8 of the Offshore EIA Report concluded that due to the limited extent of the impact of permanent habitat alteration, and the minor proportion of the protected features to be affected during decommissioning, the magnitude of the impact on the features of the Firth of Forth Banks Complex MPA was low. The shelf banks and mounds protected feature of the Firth of Forth Banks Complex MPA is considered to be of high vulnerability, low recoverability and national importance and therefore was considered to have a high sensitivity. Therefore, the significance of effect was considered to be minor adverse significance.
  4. Based on the information presented here, it can be concluded that permanent habitat alteration following the decommissioning phase, within the shelf banks and mounds feature, will not lead to a significant risk of hindering the achievement of the conservation objectives for this feature of the Firth of Forth Banks Complex MPA for the reasons detailed in paragraph 305.

Ocean quahog aggregations

  1. On the basis of the assumptions outlined in paragraph 190, and for the purposes of this assessment, it is assumed that all of the permanent habitat alteration that may occur in the Firth of Forth Banks Complex MPA in the decommissioning phase may occur within this protected feature. Up to 1.89 km2 of permanent habitat alteration may persist within supporting habitat for ocean quahog within the Firth of Forth Banks Complex MPA following the decommissioning phase. This equates to 0.09% of the total area of this feature within the Firth of Forth Banks Complex MPA. Of the total area of seabed which will be affected, up to 0.58 km2 may be within Scalp and Wee Bankie (0.03% of the total area of the feature within the MPA) and up to 1.31 km2 will occur within the Berwick Bank part of the MPA (0.06% of the total area of the feature within the MPA) (see Table 1.45   Open ▸ ). Whilst this has been described here as habitat alteration with respect to the supporting subtidal sands and gravels habitats, it is noted that this would effectively represent a reduction in the extent of soft sediment habitat available for colonisation by ocean quahog in the post-decommissioning phase.
  2. An assessment of the impacts of permanent habitat alteration for this protected feature can be found in paragraph 310. This assessment is directly applicable to this phase of the Proposed Development. The changes in the magnitude of the impact are described in paragraph 318. These changes will result in a reduced pressure on ocean quahog aggregations and provide greater habitat with a negligible impact on the surrounding environment and its supporting processes.
  3. Volume 2, chapter 8 of the Offshore EIA Report concluded that due to the limited nature of the impact of permanent habitat loss, and the minor proportion of the protected features to be affected during decommissioning, the magnitude of the impact on the features of the Firth of Forth Banks Complex MPA was low. The ocean quahog protected feature of the Firth of Forth Banks Complex MPA is considered to be of high vulnerability, low recoverability and national importance and therefore was considered to have a high sensitivity. Therefore, the significance of effect was considered to be of minor adverse significance.
  4. Based on the information presented here, it can be concluded that permanent habitat alteration, as a result of scour and cable protection for cables and cable crossings being left in situ following decommissioning, will not lead to a significant risk of hindering the achievement of the conservation objectives for this feature of the Firth of Forth Banks Complex MPA for the reasons detailed in paragraph 312.

Wee Bankie key geodiversity area

  1. On the basis of the assumptions outlined in paragraph 192, and for the purposes of this assessment, it is assumed that 22.17% of the maximum permanent habitat alteration resulting from scour and cable protection being left in situ could occur in this feature. This equates to a maximum of 0.42 km2 of permanent habitat alteration within the Wee Bankie Key Geodiversity Area, or 0.06% of the total area of this feature within the MPA. Of this up to 0.417 km2 may occur within Scalp and Wee Bankie (0.06% of the total area of the feature within the MPA) and 0.002 km2 may occur within the Berwick Bank section of the MPA (0.0003% of the total area of the feature within the MPA) (see Table 1.45   Open ▸ ).
  2. An assessment of the impact of permanent habitat alteration for this protected feature is presented in paragraph 314. The differences between the decommissioning phase and the operation and maintenance phase are described in paragraph 318. The Wee Bankie Key Geodiversity Area feature is unlikely to recover following the completion of decommissioning as the processes which formed this feature are no longer active and therefore the feature cannot recover to its previous state when some of the infrastructure is removed however it may become less obvious as it is filled in by the current sediment transport processes, but this sediment may not be representative of the original structure.
  3. In relation to the size of the feature (~750 km2), the loss of 0.06% of this area to permanent habitat alteration as a result of scour and cable protection for cables and cable crossings being left in situ is very small, and it can be concluded that during, and post, the decommissioning phase this will not lead to a significant risk of hindering the achievement of the conservation objectives for this feature of the Firth of Forth Banks Complex MPA for the same reasons detailed in paragraph 315.

Colonisation of Hard Structures