19. Marine Archaeology
19.1. Introduction
- This chapter of the Array Environmental Impact Assessment (EIA) Report presents the assessment of the likely significant effects (LSE1) (as per the “EIA Regulations”) on marine archaeology as a result of the Ossian Array which is the subject of this application (hereafter referred to as “the Array”). Specifically, this chapter assesses the LSE1 of the Array on marine archaeology during the construction, operation and maintenance, and decommissioning phases.
- The following technical chapter also informs the assessment presented in this chapter:
- volume 2, chapter 7: Physical Processes.
- This chapter summarises information contained within volume 3, appendix 19.1.
19.2. Purpose of the Chapter
- The Array EIA Report provides the Scottish Ministers, statutory and non-statutory stakeholders with adequate information to determine the LSE1 of the Array on the receiving environment. This is further outlined in volume 1, chapter 1.
- The purpose of this marine archaeology Array EIA Report chapter is to:
- present the existing environmental baseline established from desk studies, site-specific surveys, and consultation with stakeholders;
- identify any assumptions and limitations encountered in compiling the environmental information;
- present the potential impacts on marine archaeology arising from the Array and reach a conclusion on the LSE1 on marine archaeology, based on the information gathered and the analysis and assessments undertaken; and
- highlight any necessary monitoring and/or mitigation measures which are recommended to prevent, minimise, reduce or offset the likely significant adverse environmental effects of the Array on marine archaeology.
19.3. Study Area
- Figure 19.1 Open ▸ illustrates the marine archaeology study area for the Array which encompasses the:
- Array (i.e. the area in which the wind turbines will be located); and
- seabed areas that may be influenced by changes to marine archaeology due to the Array, which will encompass a wider domain.
- The marine archaeology study area consists of the Array with an additional 2 km buffer. The marine archaeology study area was used as the search area for obtaining records of known marine archaeology receptors from relevant archive databases and for the Cumulative Effects Assessment (CEA). The marine archaeology study area allows for a greater understanding of the archaeological baseline environment, with the dual purpose of enabling any archaeological trends within the region to be recognised and to allow any archaeological sites identified to be represented in a broader archaeological context. On the advice of Historic Environment Scotland (HES), an additional wider 5 km buffer was used to collect data on recorded losses in the vicinity of the Array. This 5 km recorded losses study area was used for recorded losses only, due to the imprecise spatial information associated with these records (see response in Table 19.4 Open ▸ and discussion of the recorded losses in section 19.7.3). In addition to the marine archaeology study areas, the extent of the geophysical survey data overlaps with the Array and, in places, exceeds it. The extent of these data is referred to as the ‘marine archaeology survey area’.
- Understanding of the physical processes due to the Array (see volume 2, chapter 7) has shown that there are no significant impacts for other fixed-foundation offshore wind farm projects; therefore the impedance on tidal regimes for the Array, with floating foundation wind turbines, will be even less. Changes in marine physical processes beyond the 2 km marine archaeology study area can therefore be considered negligible and so a 2 km buffer is deemed adequate in which to assess potential impacts upon marine archaeology.
19.4. Policy and Legislative Context
- Volume 1, chapter 2 of the Array EIA Report presents the policy and legislation of relevance to renewable energy infrastructure. Policy specifically in relation to marine archaeology, is contained in the Sectoral Marine Plan for Offshore Wind Energy (SMP) (Scottish Government, 2020a), the Scottish National Marine Plan (NMP) (Scottish Government, 2015), the United Kingdom (UK) Marine Policy Statement (MPS) (UK Government, 2011), the overarching National Policy Statement (NPS) for Energy (NPS EN-1) (Department for Energy Security and Net Zero, 2023a) and the National Policy Statement for Renewable Energy Infrastructure (NPS EN-3) (Department for Energy Security and Net Zero, 2023b). Table 19.1 Open ▸ presents a summary of the legislative provisions relevant to marine archaeology, with other relevant policy provisions set out in Table 19.2 Open ▸ and Table 19.3 Open ▸ .
- Further detail is presented in volume 1, chapter 2. Full details of the legislation, policy and guidance relevant to marine archaeology are presented in volume 3, appendix 19.1.
Table 19.1: Summary of Legislation Relevant to Marine Archaeology
Table 19.2: Summary of the MPS, SMP and Scottish NMP
- NPS EN-1 and EN-3 include guidance and what matters are to be considered in the assessment. These provisions are set out in Table 19.3 Open ▸ . While NPS EN-1 and NPS EN-3 do not directly apply to the Array, they highlight a number of factors relating to mitigation measures and determination of applications.
Table 19.3: Summary of NPS EN-1 and NPS EN-3 Provisions and Policy Relevant to Marine Archaeology
Figure 19.1: Marine Archaeology Study Areas
19.5. Consultation
- Table 19.4 Open ▸ presents a summary of the key issues raised during consultation activities undertaken to date specific to marine archaeology for the Array and in the Ossian Array Scoping Opinion (MD-LOT, 2023) along with how these have these have been considered in the development of this marine archaeology EIA Report chapter. Further detail is presented within volume 1, chapter 5.
Table 19.4: Summary of Issues Raised During Consultation and Scoping Opinion Representations Relevant to Marine Archaeology
19.6. Methodology to Inform Baseline
- Topic specific information has been reviewed to inform this marine archaeology baseline ( Table 19.5 Open ▸ and Table 19.6 Open ▸ ). In addition, consultation with stakeholders has been carried out to aid the collection of baseline information, such as the creation of a 5 km buffer recorded losses study area in order to capture additional potential marine archaeology receptors with imprecise positional data.
19.6.1. Desktop Study
- Information on marine archaeology within the marine archaeology study area was collected through a detailed desktop review of existing studies and datasets which are summarised in Table 19.5 Open ▸ . A dataset of wrecks and obstructions held by the United Kingdom Hydrographic Office (UKHO) was consulted, but there were no records within the marine archaeology study area. The marine archaeology technical report (volume 3, appendix 19.1) includes full details of the analysis undertaken to establish the marine archaeology baseline. The data were compiled into gazetteers (see volume 3, appendix 19.1, annexes A, B and C).
- The National Record of the Historic Environment (NRHE) data have been classified between records where material is known to be on the seabed and ‘recorded losses’. Recorded losses are records of vessels that have been lost in the area but have no verifiable positional data. They provide additional information on the historical maritime traffic of the area, but associated material is not known to survive on the seabed. Known losses are presented within a 2 km ‘marine archaeology study area’. At the request of HES, a 5 km ‘recorded losses study area’ was implemented for these records only, in order to take account for the imprecise spatial data associated with these records. Both study areas are shown in Figure 19.1 Open ▸ .
Table 19.5: Summary of Key Desktop Data