East Anglia ONE Offshore Windfarm Generation Assets Monitoring Plan


September, 2016


effort for gannet in November would also be expected to improve the ability to detect effects on kittiwake (with the power to detect displacement similar to that obtained for gannet).


24.


Thus, on the basis of the baseline surveys and the power analysis conducted, it was concluded that a nonbreeding survey with a focus on October and November (2 surveys per month) and single surveys per month in December to March (a total of 8 surveys per winter) would be able to detect displacement of the species of primary concern at EA ONE.


25.


In addition to spatial modelling of seabird distributions, which will reveal displacement effects at the scale of the wind farm, the proposed survey design and analysis methods will enable turbine avoidance distances to be estimated. This analysis will be conducted at a range of scales, spanning avoidance of individual turbines (e.g. hundreds of metres) up to avoidance of the wind farm as a whole (e.g. several kilometres). The approach is therefore suitable both for species which exhibit high levels of macro-avoidance (e.g. gannet) and also for those species which enter wind farms (e.g. auks) but may avoid approaching close to turbines, leading to lower within wind farm densities. The method is based on comparing the observed bird to turbine distances and densities, with the same measures obtained following random re-location of turbine positions (NB in each simulation the turbines are re-located by the same amount, i.e. as an array). By repeating the random simulations (e.g. 1,000 times), the likelihood that the observed bird locations have been influenced by the turbines rather than having occurred by chance can be estimated. Critically, this component of the analysis does not require a before (pre- construction) and after (post-construction) comparison but can be conducted using a single year of data.


26.


Using this method to analyse seabird densities around the wind farm it is expected that gannet macro-avoidance distances will be estimable to at least the nearest 500m.


27.


The power analysis results were agreed in principle with Natural England in a meeting on 15th April 2016, informing the survey design parameters and enabling EAOL to procure a survey contractor to undertake pre-construction surveys. Although not presented in any detail within this document, EAOL have also ensured, as part of the aerial survey procurement process, that the aerial digital methods which are proposed will also enable flight height data to be collected in order to assess the potential influence of the wind farm on gannet flight heights.


28.


The analysis methods described for the power analysis are those that will be used with the survey data, although this does not rule out additional analysis being conducted, or potential modifications to the methods in line with evolution of analytical methods.


3.1.1.2 Objectives 29.


The objective of this document is to outline the proposed ornithological surveys required to discharge the pre-construction ornithological monitoring condition 17(2)(d) in the generation assets DML.


30.


The purpose of the pre-construction ornithological surveys is to provide a baseline of information on the distribution and abundance of seabirds within and around the EA ONE offshore windfarm. The key species that are the focus of the monitoring are; gannet Morus bassanus, kittiwake Rissa tridactyla, great black-backed gull Larus marinus, guillemot Uria aalge and razorbill Alca torda.


31.


Following construction of the wind farm post-construction surveys will be undertaken to assess the magnitude of effects on these species. As noted above, and in the Aerial Survey Power Analysis report (Appendix B), this will be undertaken through before-after comparisons with the pre-construction data and also through the use of within year analysis methods. The aim of the monitoring is to test some of the key predictions and assumptions used in the assessment through direct estimation of parameters used to model effects. In particular, the monitoring will collect data to test key assumptions underpinning the project level estimates of:


• Collision mortally of gannet, kittiwake and great black-backed gull; and • Displacement of guillemot and razorbill in the non-breeding season.


32. With the primary questions to be addressed being:


a. Are gannet locations and flight heights influenced by the presence of the EA ONE windfarm? (note that this question will be asked for other species too, but gannet has been agreed as the primary focus); and, b. Are auk locations influenced by the presence of the EA ONE windfarm?


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