13.7. Baseline Environment

13.7.1. Overview of Baseline Environment

  1. The following sections provide a summary of the shipping and navigation baseline environment. The NRA (volume 3, appendix 13.1) includes full details of the analysis undertaken to develop the shipping and navigation baseline.
  2. Any proposed developments that have not yet begun construction are not considered baseline but have been considered cumulatively in section 13.12.

                        Navigational features

  1. A plot of navigational features in proximity to the Array is presented in Figure 13.2   Open ▸ based on the Admiralty Charts (UKHO, 2023) and Sailing Directions (UKHO, 2021).
  2. Three charted buoy positions are located within the site boundary, noting these are metocean buoys deployed on site. There are three additional aids to navigation in proximity to the site boundary, each equipped with an AIS transmitter; two inshore of the site boundary and within the shipping and navigation study area, and one offshore of the site boundary (approximately 1 nm outside of the shipping and navigation study area).
  3. There are charted wrecks and obstructions in vicinity of the site boundary, more commonly seen inshore. The closest is a charted wreck located 3 nm from the north-western corner of the site boundary, at an approximate depth of 67 m below Chart Datum (CD). Further details of wrecks, including non-charted wrecks which are not considered in this chapter, are provided in volume 2, chapter 19 (which classified two wrecks and one potential wreck in the Array).
  4. Seagreen 1 Offshore Wind Farm is the closest baseline offshore wind farm to the Array, located approximately 27 nm inshore of the site boundary.
  5. The Catcher Area Development (a development area, i.e. an area charted around some oil and gas fields) is charted approximately 21 nm to the east of the site boundary. Within the limits of this development area is the BW Catcher Floating, Production, Storage and Offloading (FPSO) unit with a chains and anchors zone surrounding it, as well as templates (subsea oil and gas infrastructure). A pipeline connecting to the FPSO exits the development area to its east.
  6. A subsea power cable lies south-east of the site boundary, at a minimum distance of approximately 19 nm.
  7. Further details on navigational features can be found in the NRA (volume 3, appendix 13.1).

                        Emergency response and incident overview

  1. The SAR helicopter service is operated by the Bristow Group, with the nearest base being located at Inverness Airport, approximately 113 nm north-west of the site boundary. A total of two helicopter taskings were located within the shipping and navigation study area between April 2015 and March 2023, with neither within the site boundary itself. This corresponds to an average frequency of one every four years.
  2. The closest RNLI station to the site boundary is at Aberdeen (approximately 44 nm to the north-west), where both an All-Weather Lifeboat (ALB) and Inshore Lifeboat (ILB) are in use. A total of three incidents were documented by the RNLI within the shipping and navigation study area between 2013 and 2022, corresponding to an average of one incident every three years. One of these incidents occurred within the site boundary, in 2016.
  3. A total of four incidents documented by the MAIB occurred within the shipping and navigation study area between 2012 and 2021, corresponding to an average of one incident every two to three years. Two of these incidents occurred within the site boundary, in 2015 and 2018.
  4. Further details on emergency response resources and maritime incidents can be found in the NRA (volume 3, appendix 13.1).

                        Vessel traffic movements

  1. A plot of vessel traffic survey data recorded within the shipping and navigation study area, colour-coded by vessel type, is presented in Figure 13.3   Open ▸ .
  2. During the winter survey period, an average of nine vessels per day was recorded within the shipping and navigation study area with two to three vessels per day recorded within the site boundary. During the summer survey period, an average of 11 vessels per day was recorded within the shipping and navigation study area with three to four vessels per day recorded within the site boundary.
  3. The most common vessel type across the 28 days was cargo, with four vessels per day within the shipping and navigation study area, followed by oil and gas, with three to four vessels per day. Fishing vessel and recreational vessel activity was low due to the distance of the Array offshore, which aligns with input received during consultation (see section 13.5). Within the shipping and navigation study area, there was one fishing vessel every two to three days (the majority of which were likely in transit based on speed and behaviour) and one recreational vessel every three to four days.
  4. There was broad correlation between the vessel traffic surveys and the long term data, i.e. oil and gas and cargo vessels being the most common vessel types, with minimal levels of fishing and recreational vessels.
  5. Using the principles of MGN 654 (MCA, 2021a), a total of 11 main commercial routes were identified from the long term data, presented in Figure 13.4   Open ▸ . The busiest routes were 1 and 2, which each comprised approximately two vessels per day. Routes 3 and 4 comprised approximately one vessel per day, all other routes comprised less than one vessel per day. 
  6. Detailed analysis of the vessel traffic data and the methodology behind the collection and preparation of this data are provided in the NRA (volume 3, appendix 13.1).

Figure 13.2:
Navigational Features in the Vicinity of the Array

Figure 13.2: Navigational Features in the Vicinity of the Array

Figure 13.3:
Vessels by Type (28 Days, Winter 2022 and Summer 2023)

Figure 13.3: Vessels by Type (28 Days, Winter 2022 and Summer 2023)

Figure 13.4:
Main Commercial Routes (Pre Wind Farm)

Figure 13.4: Main Commercial Routes (Pre Wind Farm)

13.7.2. Future Baseline Scenario

  1. The EIA Regulations require that “a description of the relevant aspects of the current state of the environment (baseline scenario) and an outline of the likely evolution thereof without implementation of the project, as far as natural changes from the baseline scenario can be assessed with reasonable effort on the basis of the availability of environmental information and scientific knowledge” is included within the Array EIA Report.
  2. If the Array does not come forward, an assessment of the ‘without development’ future baseline conditions has therefore also been carried out and is described within this section.
  3. For commercial vessels, potential future changes in traffic volumes are complex to predict, noting actual changes will be based on multiple factors including general market trends. Therefore, the NRA (volume 3, appendix 13.1) has considered two independent scenarios of potential growth in commercial vessel movements of 10% and 20%, with the outputs of this process accounted for within this chapter. It is likely that commercial vessels will deviate to avoid any other future wind farm developments that are under construction or in operation. This is in line with vessel behaviours observed at other UK offshore wind farms including Seagreen 1 Offshore Wind Farm and Neart na Gaoithe Offshore Wind Farm (Anatec, 2016).
  4. It should also be considered that there may be an increase in vessels associated with offshore wind farm construction and operation as further future wind farm developments are developed. Furthermore, fluctuations in oil and gas vessel activity will depend on future development and/or decommissioning, which again is heavily dependent on market conditions and is therefore difficult to predict. Precautionary future case assumptions have therefore been made with taking into account 10% and 20% increases in traffic.
  5. For commercial fishing and recreational vessel activity, there is similar uncertainty associated with long-term predictions given the limited reliable information on future trends upon which any firm assumptions can be made. Therefore, to ensure a conservative approach, 10% and 20% growth scenarios in commercial fishing vessel and recreational vessel movements have also been assumed in the NRA (volume 3, appendix 13.1).

13.7.3. Data Limitations and Assumptions

  1. Data limitations and assumptions are summarised below, with further details presented in the NRA (volume 3, appendix 13.1).

                        Automatic identification system data

  1. It is assumed that vessels under an obligation to broadcast information via AIS have done so, across all vessel traffic datasets. It has also been assumed that the details broadcast via AIS (such as vessel type and dimensions) are accurate unless clear evidence to the contrary was identified.

                        Historical incident data

  1. Although all UK commercial vessels are required to report incidents to the MAIB, this is not mandatory for non-UK vessels unless they are in a UK port, within UK territorial waters or carrying passengers to a UK port. There are also no requirements for non-commercial recreational craft to report incidents to the MAIB. Nevertheless, the MAIB incident database is considered to be a suitable source for the characterisation of historical incidents and adequate for the assessment.
  2. The RNLI incident data cannot be considered comprehensive of all incidents in the shipping and navigation study areas. Although hoax and false alarms are excluded, any incident to which a RNLI resource was not mobilised has not been accounted for in this dataset. Nevertheless, the RNLI incident data is considered to be a suitable source for the characterisation of historical incidents and adequate for the assessment.

                        United Kingdom Hydrographic Office Admiralty Charts

  1. The Admiralty charts published by the UKHO are updated periodically, and therefore the information shown may not reflect the real-time features within the region with total accuracy. Taking into account consultation undertaken, the characterisation of navigational features is considered to be suitably comprehensive and adequate for the assessment. For aids to navigation and wrecks/obstructions, only those charted and considered key to establishing the shipping and navigation baseline are shown.