Appendix 2: Impacts of Maintenance Activities 2.1 Impacts of Maintenance Activities


1 Section 9.5.2.2 of Volume 2, Chapter 9 of the ES discusses the impacts of maintenance activities on benthic and epibenthic communities.


2 Maintenance vessels attending the East Anglia ONE site throughout the operational phase will drop anchor in the case of work boats and extend jack-up legs to the seabed in the case of the larger irregular vessels. This will occur on a regular basis (estimated worst case of six work boats and two irregular vessels per day to one of the 325 jacket foundations).


3 The effect of jack-up vessel disturbance of the seabed would only occur within the East Anglia ONE site.


4


Jack-up barge spud cans have a greater footprint than anchors, but only 0.1% of the East Anglia ONE site would be affected by this. Individuals crushed beneath the spud cans would not recover in the short term, however, wind turbine foundations would be microsited as embedded mitigation to avoid direct impacts on S. spinulosa reef habitat.


5 Should cable laying or re-burial be required as maintenance, direct effects on Annex I habitat (reef) could occur at the cable lay/burial site, however the area is not considered a ‘hotspot’ for S.spinulosa reef development and therefore the risk of impacts to Annex 1 habitat is considered low. Owing to the low sensitivity in terms of tolerance and recoverability of the SS.SBR.PoR.SspiMx biotope (S.spinulosa on mixed sediment), and based on sediment modelling undertaken for East Anglia ONE, there would be no long lasting effects on Annex I habitats in the wider area.


6 The addition of cable protection and/or scour protection material would directly effect the area impacted, however the area is not considered a ‘hotspot’ for S.spinulosa reef development and therefore the risk of impacts to Annex 1 habitat is considered low.


7


If foundations are removed and replaced, there could be direct impacts on Annex I habitat if alternative foundation locations were utilised, however the area is not considered a ‘hotspot’ for S.spinulosa reef development and therefore the risk of impacts to Annex 1 habitat is considered low.


Outline Operations and Maintenance Monitoring Plan Offshore


Page 14


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