Frequency of occurrence

278. The frequency of occurrence is considered to be negligible given very low frequency of baseline anchoring, the use of cable burial / protection and charting, and increased familiarity with the project post construction.

                        Severity of consequence

279. The severity of consequence is considered to be moderate.

                        Significance of the effect

280. Overall, the severity of consequence is deemed to be moderate and the frequency of occurrence is considered to be negligible. The effect will, therefore, be of broadly acceptable significance, which is not significant in EIA terms.

                        Secondary mitigation and residual effect

281. No secondary shipping and navigation mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 13.10) is of broadly acceptable significance and ALARP which is and not significant in EIA terms.

Anchor Interaction with Mooring Lines

                        Construction phase

282. Noting water depths in the vicinity of the site boundary, the visible presence and display on charts of the buoyed construction area and promulgation of information, it is considered unlikely that vessels would attempt to anchor in the vicinity of the mooring lines (which may be wet stored during the construction phase). It is noted that this aligns with the baseline anchoring assessment undertaken on the 12 months of vessel traffic data which did not identify any anchoring activity based on the information broadcast via AIS (see volume 3, appendix 13.1).
283. As for vessel anchors, there is a risk that fishing gear may interact with any mooring lines. It is the responsibility of fishers to dynamically risk assess whether it is safe to undertake fishing activities within the Array and to make a decision as to whether or not to fish. This decision will be informed by a number of factors, which will include the charted locations of infrastructure within the Array (e.g., on UKHO charts, and other electronic charts as appropriate). Further assessment of impacts associated with fishing gear is provided in volume 2, chapter 12.
284. There is limited data available with regard to anchor and gear interaction with mooring lines and floating substructures due to lack of precedent of large scale floating wind farms, however, consequences are likely to be similar to that of the cables.

                        Frequency of occurrence

285. The frequency of occurrence is considered to be negligible given very low frequency of baseline anchoring and charting of infrastructure.

                        Severity of consequence

286. The severity of consequence is considered to be moderate.

                        Significance of the effect

287. Overall, the severity of consequence is deemed to be moderate and the frequency of occurrence is considered to be negligible. The effect will, therefore, be of broadly acceptable significance, which is not significant in EIA terms.

                        Secondary mitigation and residual effect

288. No secondary shipping and navigation mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 13.10) is of broadly acceptable significance and ALARP which is not significant in EIA terms.

                        Operation and maintenance phase

289. During the operation and maintenance phase, vessels may be more likely to enter into the Array following removal of the buoyed construction area, however consultation input indicates entry may be less frequent than at fixed foundation offshore wind farm developments (see section 13.5).
290. Noting water depths in the vicinity of the Array, the visible presence of the surface aspects of the floating substructures and display on charts of the infrastructure, it is considered unlikely that vessels would attempt to anchor in the vicinity of the mooring lines.
291. As for vessel anchors, there is a risk that fishing gear may interact with any mooring lines. It is the responsibility of fishers to dynamically risk assess whether it is safe to undertake fishing activities within the Array and to make a decision as to whether or not to fish. This decision will be informed by a number of factors, which will include the charted locations of infrastructure within the Array (e.g., on UKHO charts, and other electronic charts as appropriate).
292. As noted during the equivalent construction phase impact, there are limited data available with regards to anchor interaction with mooring lines and floating substructures, however, consequences are likely to be similar to that of the cables.

                        Frequency of occurrence

293. The frequency of occurrence is considered to be negligible given very low frequency of baseline anchoring and charting of infrastructure.

                        Severity of consequence

294. The severity of consequence is considered to be moderate.

                        Significance of the effect

295. Overall, the severity of consequence is deemed to be moderate and the frequency of occurrence is considered to be negligible. The effect will, therefore, be of broadly acceptable significance, which is not significant in EIA terms.

                        Secondary mitigation and residual effect

296. No secondary shipping and navigation mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 13.10) is of broadly acceptable significance and ALARP which is not significant in EIA terms.

                        Decommissioning phase

297. Since the methods used to remove infrastructure are expected to be similar to those used for installation, this impact is expected to be similar in nature to the equivalent construction phase impact. In particular, a buoyed decommissioning area analogous to the buoyed construction area will be in place and it is anticipated that third-party vessels will not enter. It is also noted that it is intended that all mooring lines will be removed as part of the decommissioning process.

                        Frequency of occurrence

298. The frequency of occurrence is considered to be negligible given very low frequency of baseline anchoring and charting of infrastructure.

                        Severity of consequence

299. The severity of consequence is considered to be moderate.

                        Significance of the effect

300. Overall, the severity of consequence is deemed to be moderate and the frequency of occurrence is considered to be negligible. The effect will, therefore, be of broadly acceptable significance, which is not significant in EIA terms.

                        Secondary mitigation and residual effect

301. No secondary shipping and navigation mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 13.10) is of broadly acceptable significance and ALARP which is not significant in EIA terms.

Reduction in Search and Rescue Capability

                        Construction phase

302. The construction phase will lead to an increased level of vessels and personnel in the area over baseline levels. On this basis there may be an increase in the number of incidents requiring emergency response over baseline rates.
303. Up to 7,902 return trips from construction vessels (including site preparation) may be made throughout the construction phase and will include vessels which are RAM. The presence of project vessels will increase the likelihood of an incident, with the potential to diminish emergency response capability.
304. Baseline incident rates are considered low in the area based on the data studied, with an average of less than one incident per year indicated within the MAIB, RNLI and helicopter taskings datasets. It is also noted that to date, there have only been 13 reported allision or collision incidents associated with offshore wind farms in the UK as detailed in the NRA (volume 3, appendix 13.1). While it should be considered that this only covers allisions and collisions, it is still not anticipated that the construction phase would notably increase the observed baseline incident rates.
305. Any on-site project vessels and resources associated with the construction phase will form additional resource to respond to any incidents in the area in liaison with the MCA, both in terms of incidents associated with construction activities (i.e. self-help resources), but also incidents occurring outside of the Array to third‑party vessels.
306. As required under MGN 654, the Applicant will produce and submit an ERCoP to the MCA detailing how they would cooperate and assist in the event of an incident including consideration of additional project resources that will be available (e.g. project vessels associated with construction activities). The initial ERCoP will specifically cover the construction phase.
307. The most likely consequence is a delay caused emergency response request but without notable impact on the operation. As a worst case the delay could lead to PLL.

                        Frequency of occurrence

308. The frequency of occurrence is considered to be remote based on consideration of the historical incident data and the designed in measures in place including compliance with MGN 654.

                        Severity of consequence

309. The severity of consequence is considered to be serious.

                        Significance of the effect

310. Overall, the severity of consequence is deemed to be serious and the frequency of occurrence is considered to be remote. The effect will therefore be of tolerable significance and ALARP, which is not significant in EIA terms.

                        Secondary mitigation and residual effect

311. No secondary shipping and navigation mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 13.10) is of tolerable significance and ALARP which is not significant in EIA terms.

                        Operation and maintenance phase

312. The operation and maintenance phase will lead to an increased level of vessels and personnel in the area over baseline levels, however, it is likely to be considerably less than during the construction phase (when more vessels will be present and more activity being undertaken). On this basis there may be an increase in the number of incidents requiring emergency response over baseline rates, albeit likely at lower rates than during the construction phase.
313. As per the equivalent construction phase discussion, baseline incident rates are considered low in the area, and it is considered unlikely that incident rates will rise notably based on the study of allision and collision incidents that have occurred at other UK offshore wind farms (further details provided in volume 3, appendix 13.1).
314. Any on-site project vessels and resources associated with the operation and maintenance phase will form additional resource to respond to any incidents in the area in liaison with the MCA, both in terms of incidents associated with the ongoing operation and maintenance activities (i.e. self-help resources), but also incidents occurring outside of the Array to third‑party vessels.
315. As required under MGN 654 (MCA, 2021a), the Applicant will produce and submit an ERCoP to the MCA detailing how they would cooperate and assist in the event of an incident including consideration of additional project resources that will be available (e.g. project vessels associated with operation and maintenance activities). The ERCoP will be updated on a regular basis as required by the MCA, and this will include the transfer of the construction phase ERCoP into the operation and maintenance phase ERCoP in advance of the completion of construction. The Applicant will also agree a SAR checklist with the MCA post consent, which will set out the required mitigations of relevance to SAR that will be implemented.
316. To ensure suitable SAR access is maintained, the final layout of structures will be agreed with the MCA post consent. This will include application of the SAR layout requirements within MGN 654 (MCA, 2021a), noting that there may also be a need for use of Helicopter Refuge Areas given the size of the site boundary. The consideration of MGN 654 in addition to agreement of the layout positions with the MCA will ensure that suitable SAR access is maintained.
317. The most likely consequence is a delay caused emergency response request but without notable impact on the operation. As a worst case the delay could lead to PLL.

                        Frequency of occurrence

318. The frequency of occurrence is considered to be remote based on consideration of the historical incident data and the designed in measures in place including compliance with MGN 654.

                        Severity of consequence

319. The severity of consequence is considered to be serious.

                        Significance of the effect

320. Overall, the severity of consequence is deemed to be serious and the frequency of occurrence is considered to be remote. The effect will, therefore, be of tolerable significance and ALARP, which is not significant in EIA terms.

                        Secondary mitigation and residual effect

321. No secondary shipping and navigation mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 13.10) is of tolerable significance and ALARP which is not significant in EIA terms.

                        Decommissioning phase

322. Since the methods used to remove infrastructure are expected to be similar to those used for installation, this impact is expected to be similar in nature to the equivalent construction phase impact. In particular, a buoyed decommissioning area analogous to the buoyed construction area will be in place and it is anticipated that third-party vessels would be unlikely to enter on a regular basis.
323. This also includes the assumption that the vessels on site associated with decommissioning activities will form additional resource to respond to any incidents in the area in liaison with the MCA, both in terms of incidents associated with the decommissioning activities (i.e. self-help resources), but also incidents occurring outside of the Array to third‑party vessels.
324. As required under MGN 654 (MCA, 2021a), the Applicant will produce and submit an ERCoP to the MCA detailing how they would cooperate and assist in the event of an incident including consideration of additional project resources that will be available (e.g. project vessels associated with decommissioning). The ERCoP will be updated on a regular basis as required by the MCA, and this will include an update prior to decommissioning.
325. The most likely consequence is a delay caused emergency response request but without notable impact on the operation. As a worst case the delay could lead to PLL.

                        Frequency of occurrence

326. The frequency of occurrence is considered to be remote based on consideration of the historical incident data and the designed in measures in place including compliance with MGN 654.

                        Severity of consequence

327. The severity of consequence is considered to be serious.

                        Significance of the effect

328. Overall, the severity of consequence is deemed to be serious and the frequency of occurrence is considered to be remote. The effect will, therefore, be of tolerable significance and ALARP, which is not significant in EIA terms.

                        Secondary mitigation and residual effect

329. No secondary shipping and navigation mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 13.10) is of tolerable significance and ALARP which is not significant in EIA terms.