7.4. Marine Archaeology

7.4.1. Introduction

This section of this Scoping Report presents the relevant marine archaeology considerations of the Array and considers the scope of the assessment on marine archaeology from the construction, operation and maintenance, and decommissioning of the Array.

7.4.2. Study Area

The marine archaeology study area encompasses the site boundary, as well as a 2 km buffer surrounding the site boundary to provide a wider context with regard to marine archaeology and to identify marine archaeology receptors which could be subject to indirect effects ( Figure 7.7 Open ▸ ).

7.4.3. Baseline Environment

This section provides a summary of the baseline environment within the Array, with further detail provided in Appendix 11.
A geophysical survey was undertaken across the whole area comprising the site boundary between March and July 2022. The data was collected to the appropriate specification in order to achieve the following interpretation requirements (as per Wessex Archaeology for The Crown Estate (TCE) (2021)):

magnetometer: identification of contacts > 5 nT (phase 1A), and >10 nT (phase 1b);
Sidescan sonar (SSS): ensonfication of contacts > 0.5 m;
Sub-Bottom Profiler (SBP): penetration 5 m to 10 m; and
Multibeam Echosounder (MBES): ensonification of contacts < 1.0 m.

All data were collected and referenced relative to the WGS84 datum and UTM30N projection, which is the standard coordinate system and map projection for offshore use (Wessex Archaeology for TCE (2021). Archaeological features within the 2 km buffer will be identified from desk based sources.
Appendix 11, Apx Table 11.2 Open ▸ presents the details of the survey specification of the offshore geophysical survey. A summary of the archaeological features of the site boundary is provided below.

Submerged prehistoric archaeology

No prehistoric archaeological material has been recorded within the site boundary to date and it is unlikely that any archaeological material from the Palaeolithic and/or Mesolithic periods will survive within the site boundary due to the effects of repeated glaciations, marine transgressions and associated fluvial activity. It is unlikely that these will be present, however, further assessment of archaeological data will be included within a standalone Marine Archaeology Technical Report which will be produced to inform a robust mitigation strategy (see paragraph 593 for more information).

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Figure 7.7: Marine Archaeology Study Area

Maritime and aviation archaeology

There are no Historic Marine Protected Areas (HMPAs) or designated sites recorded within the limits of the site boundary, and no wrecks or obstructions lie within the site boundary or marine archaeology study area as recorded by the UK Hydrographic Office (UKHO) ( Figure 7.8 Open ▸ ).
A total of four recorded losses attributed to coordinates within the marine archaeology study area are held by Historic Environment Scotland (HES): Svein Jarl (Canmore ID: 314131), Titan (Canmore ID: 328826), Duva (Canmore ID: 313790), and Scottish Queen (Canmore ID: 313238) (Canmore, 2022; see Appendix 11, Apx. Table 11.4). It should be noted that as these are recorded losses, not confirmed wrecks, these may not be present within the site boundary. Further assessment of archaeological data will be included within a standalone Marine Archaeology Technical Report to clarify presence or absence of these wrecks.
Two wrecks were recorded during the initial geophysical survey (Ocean Infinity, 2022a); however, these are not recorded by the UKHO. One wreck (named as ‘Contact S_NM_B_0001’ within the geophysical survey report (Ocean Infinity, 2022a)) has been entered into the Canmore National Records of the Historic Environment (NRHE) database with ID number: 372595. The second wreck will be entered in to the NRHE database in the future. These wrecks are detailed in a gazetteer in Appendix 11 (Apx. Table 11.4). These wrecks may relate to the NRHE records noted in paragraph 587, however, this is not confirmed at present. The data from the initial geophysical survey will be further assessed by a marine archaeology specialist and results presented within a standalone Marine Archaeology Technical Report. Further details are presented in paragraph 593.

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Figure 7.8: Position of UKHO Records in the Vicinity of the Site Boundary

7.4.4. Potential Array Impacts

Potential impacts on marine archaeology which may occur during the construction, operation and maintenance, and decommissioning phases of the Array in the absence of designed in measures have been identified in Table 7.12 Open ▸ .

Table 7.12: Potential Impacts Identified for Marine Archaeology in the Absence of Designed In Measures

Potential Impact	Justification
Construction
Sediment disturbance and deposition leading to indirect impacts on marine archaeology receptors	There is potential for sediment disturbance and deposition as a result of site preparation and construction activities which could lead to indirect impacts on marine archaeology receptors.
Direct damage to maritime archaeology receptors (e.g. wrecks, debris, submerged prehistoric receptors palaeolandscapes and associated archaeological receptors)	As a result of site preparation and construction activities, there is potential for direct damage to maritime receptors on the surface of the seabed.
Direct damage to deeply buried marine archaeology receptors – submerged prehistoric receptors (e.g. palaeolandscapes and associated archaeological receptors)	As a result of site preparation and construction activities, there is potential for direct damage to submerged maritime receptors.
Operation and Maintenance
Sediment disturbance and deposition leading to indirect impacts on marine archaeology receptors	There is potential for sediment disturbance and deposition as a result of operation and maintenance activities such as inter-array and interconnector cable repair and reburial activities and any associated jack-up vessel and vessel anchoring activities.
Direct damage to maritime archaeology receptors (e.g. wrecks, debris, submerged prehistoric receptors palaeolandscapes and associated archaeological receptors)	There is potential for direct damage to maritime receptors during the operation and maintenance phase due to maintenance activities such as component replacement activities using jack-up vessels, inter-array and interconnector cable repair or reburial activities, and any associated vessel anchor deployments.
Alteration of sediment transport regimes leading to indirect impacts on marine archaeology receptors	There is potential for sediment transport regimes to be altered as a result of the presence of infrastructure on the seabed.
Decommissioning
Sediment disturbance and deposition leading to indirect impacts on marine archaeology receptors	The impacts of decommissioning are predicted to be no greater than those for construction, as set out above.
Direct damage to maritime archaeology receptors (e.g. wrecks, debris, submerged prehistoric receptors palaeolandscapes and associated archaeological receptors)	The impacts of decommissioning are predicted to be no greater than those for construction, as set out above.
Direct damage to deeply buried marine archaeology receptors – submerged prehistoric receptors (e.g. palaeolandscapes and associated archaeological receptors)	The impacts of decommissioning are predicted to be no greater than those for construction, as set out above.

7.4.5. Designed In Measures

The following designed in measures, and how these can reduce potential for impact have been considered in the identification of potential impacts associated with the Array assessment:

The implementation of AEZs around sites identified as having a known important archaeological potential to mitigate the potential impacts from offshore infrastructure. The size of the AEZ will be evidence-based and established using the precautionary principle to ensure that it is of sufficient size (likely to be 50 – 100 m buffer) to protect the site from the nature of impact (Wessex Archaeology, 2007; Wessex Archaeology for TCE, 2021).
Archaeological input into specifications for and analysis of future preconstruction geophysical surveys.
Archaeologists to be consulted in the preparation of any preconstruction Remotely Operated Vehicle (ROV) or diver surveys and in monitoring/checking of data, if appropriate based upon the findings of the archaeological assessment of geophysical survey data.
All anomalies of possible archaeological potential will be reviewed against the final layout and design. If they are likely to be impacted, these anomalies would undergo further archaeological investigation. Should these anomalies prove to be of archaeological importance then future AEZs may be implemented following consultation with HES.
Archaeological input into specifications for and analysis of future preconstruction geotechnical surveys, including the presence of a geoarchaeologist on board the survey vessel and a provision for sampling, analysis and reporting of recovered cores, if required. The results of all geoarchaeological investigations to be complied in a final report which includes a sediment deposit model.
Commitment to preparation and agreement on an Offshore Written Scheme of Investigation (WSI) and Protocol of Archaeological Discoveries (PAD), similar to that set out by TCE (2014), prior to any interaction with the seabed.
Archaeologists to be consulted in advance of pre-construction site preparation activities and, if appropriate, to carry out watching briefs of such work. The requirement for watching briefs is determined during the lifecycle of the project. If previously unknown discoveries of archaeological significance are made, an archaeologist may be required on-board to monitor and provide on-site advice of how best to avoid/record/preserve discoveries of archaeological significance.
Micro-siting of wind turbine foundation mooring and anchoring systems, Offshore Substation Platform (OSP) foundations, and inter-array cabling to avoid known wrecks.
Mitigation of unavoidable direct impacts on known sites of archaeological importance. Options include i) preservation by record, ii) stabilisation and iii) detailed analysis and safeguarding of otherwise comparable sites elsewhere.

7.4.6. Potential Impacts After the Implementation of Designed In Measures

Considering the marine archaeology baseline information presented within section 7.4.3 and Appendix 11, the proposed designed in measures, and the project description presented in section 2, it is proposed that all impacts are to be scoped out of the assessment for marine archaeology. Table 7.13 Open ▸ presents these impacts alongside a justification for scoping them out.

Table 7.13: Impacts Proposed to be Scoped Out of the Array Assessment for Marine Archaeology

Impact	Justification
Construction
Sediment disturbance and deposition leading to indirect impacts on marine archaeology receptors.	A Marine Archaeology Technical Report, together with associated data review of the geophysical data for the Array, will provide an overview of the identifiable marine archaeology features within the marine archaeology study area. This Marine Archaeology Technical Report will form the basis of an Outline WSI and PAD, which will be prepared for approval by HES. The Marine Archaeology Technical Report, Outline WSI and PAD will be submitted alongside the Array Environmental Impact Assessment (EIA) Report, with the Outline WSI and PAD updated post-consent. The Outline WSI and PAD will include (as outlined above): the identification of AEZs around sites identified as having a known important archaeological potential; archaeological input into specifications for and analysis of future pre-construction geophysical surveys; archaeologists to be consulted in the preparation of any pre-construction ROV/diver surveys and in monitoring/checking of data if appropriate; all anomalies of possible archaeological potential will be reviewed against the final layout and design; archaeological input into specifications for and analysis of future pre-construction geotechnical surveys; provision of a PAD similar to that set out by TCE (2014) for unexpected archaeological discoveries; archaeologists to be consulted in advance of pre-construction site preparation activities and, if appropriate, to carry out watching briefs of such work; micro-siting of wind turbine foundation anchors and mooring lines to avoid known wrecks; and mitigation of unavoidable direct impacts on known sites of archaeological importance. Options include i) preservation by record, ii) stabilisation and iii) detailed analysis and safeguarding of otherwise comparable sites elsewhere. Therefore, the provision of an Outline WSI and PAD will mitigate any impacts to known, unconfirmed or unexpected discoveries of archaeological potential and will ensure that all impacts are reduced to not significant in EIA terms, and it is proposed to scope marine archaeology out of the Array EIA Report on this basis.
Direct damage to maritime archaeology receptors (e.g. wrecks, debris, submerged prehistoric receptors palaeolandscapes and associated archaeological receptors).
Direct damage to deeply buried marine archaeology receptors – submerged prehistoric receptors (e.g. palaeolandscapes and associated archaeological receptors).
Alteration of sediment transport regimes leading to indirect impacts on marine archaeology receptors.
Operation and Maintenance
Sediment disturbance and deposition leading to indirect impacts on marine archaeology receptors.	Justification as described within construction phase.
Direct damage to maritime archaeology receptors (e.g. wrecks, debris, submerged prehistoric receptors palaeolandscapes and associated archaeological receptors).
Direct damage to deeply buried marine archaeology receptors – submerged prehistoric receptors (e.g. palaeolandscapes and associated archaeological receptors).
Alteration of sediment transport regimes leading to indirect impacts on marine archaeology receptors.
Decommissioning
Sediment disturbance and deposition leading to indirect impacts on marine archaeology receptors.	Justification as described within construction phase.
Direct damage to maritime archaeology receptors (e.g. wrecks, debris, submerged prehistoric receptors palaeolandscapes and associated archaeological receptors).
Direct damage to deeply buried marine archaeology receptors – submerged prehistoric receptors (e.g. palaeolandscapes and associated archaeological receptors).
Alteration of sediment transport regimes leading to indirect impacts on marine archaeology receptors.

7.4.7. Proposed Approach to the Environmental Impact Assessment

A Marine Archaeology Technical Report will be prepared to characterise the baseline conditions for the Array, which will be used in the Outline WSI and PAD. These documents will be prepared and submitted alongside the Array EIA Report, with the Outline WSI and PAD updated post-consent. As noted in Table 7.13 Open ▸ , the Outline WSI and PAD form the basis of the proposal to scope marine archaeology out of the Array EIA Report as their application within the construction, operation and maintenance, and decommissioning phases of the Array will ensure that any impacts to marine archaeology receptors will be mitigated to a non-significant level in EIA terms.
If agreement to scope out marine archaeology from the Array EIA Report is not reached, the Array EIA chapter will follow the methodology set out in section 4 of this Scoping Report.
Specific to the marine archaeology, the following guidance documents and legislation will also be considered:

Protection of Military Remains Act 1986;
Ancient Monuments and Areas Act 1979;
Merchant Shipping Act 1995;
Marine Policy Statement 2011;
Standard and guidance for historic environment desk-based assessment (Chartered Institute for Archaeologists, 2020);
Scottish NMP (Scottish Government, 2015);
Designation Policy and Selection Guidance (HES, 2020);
Code of Conduct (Chartered Institute for Archaeologists, 2014);
COWRIE Historic Environment Guidance for the Offshore Renewable Energy Sector (Wessex Archaeology, 2007);
Offshore Renewables protocol for Archaeological Discoveries (TCE, 2014);
Offshore Geotechnical Investigations and Historic Environment Analysis: Guidance for the Renewable Energy Sector (Gribble and Leather, 2010);
Archaeological Written Schemes of Investigation for Offshore Wind Farm Projects (Wessex Archaeology for TCE, 2021); and
Code of Practice for Seabed Development (Joint Nautical Archaeology Policy Committee (JNAPC), 2006).

Marine Archaeology Technical Report

The Marine Archaeology Technical Report will be submitted as part of the Array EIA Report and will include a description of the baseline conditions of the site boundary with regard to marine archaeology, which will be supplemented by an assessment of the site-specific geophysical survey. The methodology to be followed for these activities is set out below.

Baseline characterisation

The Marine Archaeology Technical Report will include a detailed desktop review of marine archaeology which will be prepared using existing studies and datasets (additional to those presented in this Scoping Report) from the following primary sources:

records of UKHO wrecks and obstructions;
Historic Environment Records (HERs) and NRHE data provided by HES and local councils; and
records of HMPAs held by Historic Environment Scotland in their online Historic Environment Portal.

The Applicant has requested HERs and NRHE data from HES and local authority archaeologists at the time of writing, which will provide additional detail of the archaeological potential within the site boundary and Array for the Marine Archaeology Technical Report. In addition, the geophysical anomalies identified during the geophysical survey will be further discussed and assessed within the Marine Archaeology Technical Report.
The general distribution of known wreck sites and geophysical anomalies with archaeological potential will be identified by plotting the baseline data. Information drawn from secondary sources may be used qualitatively to gain an understanding of the likelihood of unknown and unrecorded maritime archaeological sites.

Geophysical data assessment

A qualified and experienced maritime archaeologist with a background in geophysical and hydrographic data acquisition, processing and interpretation will undertake the archaeological review of the Array geophysical data (see section 7.4.3 and Appendix 11), comprising an initial review of the data (including magnetometer, SSS, SBP and MBES), to gain an understanding of the geological and topographic make-up of the Array and any marine archaeology that is visible on the seabed. This assessment will inform the Marine Archaeology Technical Report and Outline WSI and PAD.
The primary use of SBP and MBES, outside of seabed and paleo-landscape characterisation, is in the corroboration of contacts identified in the SSS and magnetometer data. Therefore, SBP and MBES data will be used alongside the magnetometer data to corroborate all identified contacts of potential anthropogenic origin to assess for archaeological potential.
The criteria outlined in Table 7.14 Open ▸ will be used to assign the archaeological potential to each identified contact.

Table 7.14: Criteria for the Assessment of Archaeological Potential to be applied within the Marine Archaeology Technical Report

Potential	Criteria
Low	An anomaly potentially of anthropogenic origin but that is unlikely to be of archaeological significance – Examples may include discarded modern debris such as rope, cable, chain or fishing gear; small isolated anomalies with no wider context; or small boulder-like features with associated magnetometer readings.
Medium	An anomaly believed to be of anthropogenic origin but that would require further investigation to establish its archaeological significance – Examples may include larger unidentifiable debris or clusters of debris, unidentifiable structures, or significant magnetic anomalies.
High	An anomaly almost certainly of anthropogenic origin and with a high potential of being of archaeological significance – high potential anomalies tend to be the remains of wrecks, the suspected remains of wrecks, or known structures of archaeological significance.

7.4.8. Potential Cumulative Effects

It is currently understood that no potential cumulative impacts will occur as a result of the Array during the construction, operation and maintenance, or decommissioning phases as the application of designed in measures will be sufficient in reducing any potential cumulative impacts. In addition, it is anticipated that other parts of the Ossian project (i.e. the Proposed offshore export cable corridor(s) and Proposed onshore export cable corridor(s)) would implement these designed in measures which would mitigate impacts and potential cumulative impacts, therefore, it is unlikely there will be any significant cumulative impacts between the Ossian projects. Therefore, this will not be considered further within the Array EIA Report.

7.4.9. Potential Transboundary Impacts

Appendix 3 presents the transboundary impacts screening which has been carried out for the Array. There will be no pathway for impacts beyond the 2 km marine archaeology study area and, therefore, no potential for significant transboundary effects with regard to marine archaeology from the Array upon the interests of EEA states. Therefore, it is proposed that this will not be considered further within the Array EIA Report.

7.4.10. Scoping Questions to Consultees

Do you agree with the marine archaeology study area as defined e.g. the site boundary and a wider search area encompassing 2 km from the limits of the site boundary?
Do you agree that the designed in measures described are suitable for managing and mitigating the potential effects of the site boundary on the marine archaeology receptors?
Do you agree that it is appropriate to scope out those impacts proposed to be scoped out, and that the assessment of marine archaeology receptors should be scoped out of the Array EIA Report?

7.4.11. Next Steps

As Marine Archaeology is proposed to be scoped out of the Array EIA Report, the next step will be to reach agreement on this with the stakeholders via consultation. An outline WSI, PAD, and Marine Archaeology Technical Report will be developed for the Array and will be submitted to stakeholders for further discussion and agreement. The over-arching next steps are outlined in section 4.3.4.