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208.


It is anticipated that any hard substrate associated with of the installation of 100 GBS foundations and scour protection, other windfarm associated infrastructure and inter-array and offshore export cable protection (including cable crossings) would be in discrete areas and would not be continuous along large lengths of either inter- array or offshore export cables. The magnitude of effect of the introduction of hard substrate in this case is therefore considered to be low.


209. Based on the results of the post monitoring surveys cited above, any changes in the community structure and abundance of fish and shellfish species within the East Anglia THREE project are likely to be small. Therefore the sensitivity of fish and shellfish receptors to the introduction of hard substrate is considered to be low to medium. As a result of the negligible magnitude and the low to medium sensitivity of the receptors, the impact is expected to be of minor adverse significance.


210. Table 11.27 summarises the potential impact of introduction of hard substrate during the operational phase.


Table 11.27 impact of introduction of hard substrate during the operational phase Receptor Group


Fish and Shellfish


Receptor sensitivity Low to Medium


Magnitude of Effect Low


Impact Significance Minor adverse


11.6.2.3 Impact 3: Operational noise 211. Sources of operational noise would include wind turbine vibration, the contact of waves with offshore structures and maintenance vessel engines. It is likely that these would increase noise levels above existing baseline levels (i.e. pre- construction).


212. Background levels of noise in coastal waters in the UK are commonly 130 dB re μPa (Nedwell et al. 2003). Noise monitoring studies in the UK have shown operational noise levels from North Hoyle, Scroby Sands, Kentish Flats and Barrow windfarms to be only marginally above ambient noise levels (Cefas. 2010, Nedwell et al. 2007a and Edwards et al. 2007). Operational noise measurements undertaken in Germany have also found that noise levels were similar to background ambient noise levels (Betke et al. 2004).


213. A review of monitoring data from operational UK offshore wind farms by CEFAS (2009) indicated that there was no evidence from post-construction fish surveys that operational noise had resulted in significant impacts on fish populations, either in terms of changes to species composition or reductions in abundance. Furthermore, recent studies involving comprehensive fish surveys in operational wind farm sites


Preliminary Environmental Information May 2014


East Anglia THREE Offshore Windfarm


Chapter 11 Fish and Shellfish Page 72


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