Walney Extension Offshore Wind Farm - Planning … · Stage E: CRM for Barrow OWF and apportionment...

March 2014

WALNEY

EXTENSION

OFFSHORE

WIND FARM

Walney Extension Offshore Wind Farm

Offshore Ornithology

Clarification Note: Lesser Black-backed Gull In-combination

Collision Risk Assessment and SPA Apportioning

Walney Extension Offshore Windfarm

Clarification Note – LBBG In-combination CRM

March 2014 Page 1


Clarification Note–Offshore Ornithology lesser black-backed gull

DONG Energy Walney Extension (UK) Ltd.

33 Grosvenor Place, Belgravia, London, SW1X 7HY

Version: 2

Date: March 2014

© DONG Energy Power (UK) Ltd., 2014. All rights reserved.

Pictures: © DONG Energy Power (UK) Ltd., 2014.

Prepared by: Ian Ellis (NIRAS Consulting Ltd)

Checked: Robin Ward (NIRAS Consulting Ltd)

Accepted: Allen Risby (DONG Energy)

Approved: Sally Holroyd (DONG Energy)

Revision history

Version Date Author History

1 06/02/2014 Ian Ellis (NIRAS) First Draft

2 03/03/2014 Allen Risby (DONG Energy) Update and finalisation


Clarification Note – LBBG in-combination CRM

March 2014 Page 2

1. Introduction

1.1 DONG Energy Walney Extension (UK) Ltd (‘the Applicant’) made an application to the Planning

Inspectorate (PINS) in June 2013 for a Development Consent Order (DCO) for the Walney

Extension Offshore Wind Farm (‘the Project’) located in the Irish Sea.

1.2 This Paper provides further clarification on the Walney Extension ornithological impact

assessment, specifically on the information presented concerning the in-combination

assessment for lesser black-backed gull. This Paper has been prepared in response to Natural

England’s Written Representations, dated 16 December 2013; particularly Dr Alex Banks’

Expert Report paragraphs 25–29, 78-79 and 129-135.

1.3 The focus of this paper is the refinement of the analysis of the potential in-combination effect

on Morecambe Bay, Ribble & Alt Estuaries and Bowland Fells SPAs, all of which support a

qualifying feature of breeding lesser black-backed gull. The analytical refinements described in

this paper provide a more accurate and robust interpretation of the potential in-combination

effects on lesser black-backed gull than has previously been available.

1.4 The Paper makes extensive reference to the parallel analysis undertaken for Burbo Bank

Extension Offshore Wind Farm (NIRAS Consulting 2013a&b; DONG Energy 2013a, DONG Energy

2014a&b1). The analysis undertaken for the Burbo Bank Extension project considers the same

set of in-combination projects as the Walney Extension Project and also considers the same set

of lesser black-backed gull SPA colonies. The development of the analysis presented for Burbo

Bank Extension included extensive consultation with Natural England, particular focusing on

the application of several detailed analytical stages with the outcome being a robust

assessment of the potential in-combination effects on this species.

1.5 A further objective of this paper is to update the in-combination assessment using the tiered

approach recently developed by JNCC and Natural England (JNCC and Natural England, 2013a).

1.6 In summary, this paper re-evaluates the in-combination assessment carried out for lesser

black-backed gull taking into account the following:

Updated regional population data;

A more accurate understanding of the location of the breeding colony in relation to the

proposed wind farm and the likelihood that foraging birds from the colony would be

exposed to collision risk;

More accurate information about the actual effects of existing wind farms within foraging

range of the breeding colony;

Apportionment of CRM estimates to all lesser black-backed gull colonies within foraging

range;

Inclusion of apportioned CRM estimates for Gwynt y Môr, Rhyl Flats, Burbo Bank and North

Hoyle offshore wind farms;

1 Documents submitted by DONG Energy to the Burbo Bank Extension Planning Inspectorate Examination and

available on the PINS website http://infrastructure.planningportal.gov.uk/projects/north-west/burbo-bank-extension-offshore-wind-farm/

http://infrastructure.planningportal.gov.uk/projects/north-west/burbo-bank-extension-offshore-wind-farm/

http://infrastructure.planningportal.gov.uk/projects/north-west/burbo-bank-extension-offshore-wind-farm/



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Formulation of a CRM for Barrow Offshore Wind Farm;

Adjustment of the predicted effects of other wind farms in light of historical changes in SPA

population size; and

Application of JNCC and Natural England’s tiered approach to addressing in-combination

effects.

2. Methodology

2.1 For transparency the assessment is undertaken and presented in a series of analytical stages.

Stages A – G all refer to methodological updates to the assessment and investigate corrections

and adjustments applied to collision risk estimates for the Project Site and other sites

considered in the in-combination assessment. Once these refinements have been undertaken,

the tiered approach to in-combination assessment suggested by JNCC and Natural England

(JNCC and Natural England, 2013a) is defined and applied to the established results at each

stage.

2.2 Collision risk estimates for the Project site are taken from the Walney Extension HRA Report2 in

the first instance and are based, according to advice from Natural England3, on Option 24 of the

Band (2012) Collision Risk Model. The Applicant does however consider that Option 3 (or the

‘extended model’) of Band (2012) provides the most mathematically advanced representation

of potential collision risk to bird species currently available. Option 3 allows for consideration

of the distribution of birds within the wide Potential Collision Height (PCH) band in contrast to

the basic Option 1 model which assumes even distribution within this area. Option 3 results

are therefore also provided in this assessment and are fully detailed within Appendices 13.1

and 13.2.

2.3 The following analytical Stages are implemented in this paper:

Stage A : Update of population data, foraging range definition and ‘as built’ scenarios of in-

combination projects;

Stage B : Investigation of breeding period definition in historic CRM assessments;

Stage C : Apportionment of CRM estimates to all colonies within foraging range;

Stage D: Apportionment of CRM estimates as presented in the Gwynt y Môr Appropriate

Assessment;

Stage E: CRM for Barrow OWF and apportionment to source colonies;

Stage F: Investigation of potential effects of breeding colony size changes on historic CRM

estimates; and

2 Annex 2 : Assigning birds to SPAs and Potential Biological Removal (DONG Energy, 2013)

3 Natural England Relevant Representations Paragraph 4.1.5 (Natural England 20 September 2013)

4 There are considered to be too few flight records for this species at the Project site during the breeding

season to support the use of option 1 (DONG Energy, 2014c)



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Stage G: Further considerations of CRM predictions – age structure within recorded gulls.

2.4 At each stage of the analysis the collision predictions will be presented and apportioned to

each of the three relevant SPAs5 which support a breeding lesser black-backed gull qualifying

feature and for which the Project site is considered to be within mean maximum foraging range

for this species (141 km (Thaxter et al., 2012)).

2.5 Consistent with the process undertaken for Appendix 2 of the HRA Report, the estimated

magnitude of collision risk on lesser black-backed gull is assessed through Potential Biological

Removal (PBR). The PBR is updated in this report to take account of the extensive data on

annual survival now available from the Skomer colony of lesser black-backed gull (JNCC, 2013).

All other parameters used to calculate the PBR remain identical to those presented in Appendix

2 of the HRA Report.

2.6 Table 1 presents PBR values for each SPA accounting for the revised survival rate for lesser

black-backed gull. The recovery factor f is an arbitrary value from 1.0 to 0.1 and its purpose is

to allow conservatism in the calculation of PBR or to identify a value for PBR that is intended to

achieve a specific outcome for nature conservation (e.g. population recovery). Dillingham &

Fletcher (2008) link the value of f to conservation status and (following (IUCN status criteria6)

suggest that f=0.1 is adopted for ‘threatened’ species, f=0.3 for ‘near threatened’ species and

f=0.5 for species of ‘least concern’. They further argue that a value of f=1.0 may be suitable for

species of ‘least concern’ that are known to be increasing or stable.

Table 1: PBR values for each SPA using updated annual survival data.

PBR f value Morecambe Bay SPA Ribble & Alt Estuaries SPA Bowland Fells SPA

1.0 1002.3 507.0 673.4

0.5 501.2 253.5 336.7

0.4 400.9 202.8 269.4

0.3 300.7 152.1 202.0

0.2 200.5 101.4 134.7

0.1 100.2 50.7 67.4

2.7 Natural England, within their Written Representations (Paragraphs 132-133) suggest that f

values of 0.1 – 0.3 may be more appropriate in the case of lesser black-backed gulls at

Morecambe Bay SPA. With this uncertainty in mind, and noting that f values represent a

continuous scale, the Applicant in this paper presents a matrix approach showing the CRM

results and the corresponding f value.

2.8 The following sections work through the analysis of collision risk in stages A to G.

5 Morecambe Bay SPA, Ribble and Alt Estuaries SPA, and Bowland Fells SPA

6 http://www.iucnredlist.org/technical-documents/categories-and-criteria

http://www.iucnredlist.org/technical-documents/categories-and-criteria



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3. Stage A : Update of population data, foraging range definition and ‘as built’ scenarios of in-

combination projects

(i) Contemporary population data

3.1 The analysis presented in the HRA Report and Environmental Statement (DONG Energy, 2013)

apportioned collision estimates at the Project site to source colonies. To inform this analysis,

population data held within the JNCC SMP Database were used.

3.2 An atlas survey of the breeding birds of Lancashire and North Merseyside for the period 2008-

2011 (White et al. 2013), was published subsequent to the completion of the HRA Report. The

Atlas provides contemporary data on lesser black-backed gull populations not included in the

JNCC SMP database and, for some colonies, provides data that are more contemporaneous

with the date of the Project site-specific surveys. These data were considered as highly relevant

to the in-combination assessment and this complies with the overarching approach developed

with Natural England7. In some cases, White et al. (2013) count data are given for broadly

defined areas (e.g. ‘Liverpool population’) and not all or some of its constituent colonies. In

such cases, the number of breeding birds have been evenly distributed between the

constituent SMP sites, modified in accordance with any site specific information provided by

White et al. (2013). The inclusion of this updated regional population data of lesser black-

backed gulls leads to adjustment of the apportioning of collision effects predicted for the

Project site and the other wind farm sites considered in-combination.

(ii) Foraging range definition

3.3 The precise location of the breeding colony within the SPA is used to refine the understanding

of the distance between the breeding colony and the proposed wind farm and the likelihood

that birds from the colony will forage within the wind farm area. This updates previous analysis

which used the boundary of the SPA to determine foraging range.

3.4 This update is particularly relevant to Morecambe Bay SPA where the lesser black-backed gull

colony is confined to a single location (South Walney) within this extensive SPA. This allows for

greater precision in determining the likely source of lesser black-backed gulls in a given area.

3.5 In addition, at this stage, the collision risk results obtained for projects considered in-

combination have also been re-apportioned to take account of the colony size at the time of

the survey (e.g. surveys for the Ormonde offshore wind farm were undertaken in 2004 so that

apportionment is now based on the colony size during that year).

(iii) Correction of historic CRM estimates to account for revised built turbine scenarios

3.6 Collision risk estimates sourced from planning application documents were used and presented

in the HRA Report for the Project without further modification. These values were based upon

7 The Project site specific surveys covered the breeding seasons in 2011 and 2012, so colony census data

including those years are likely to be the most appropriate for the assessment of potential effects. This approach is in accordance with the advice received from Natural England.



March 2014 Page 6

collision risk modelling using turbine array design envelopes (the "Rochdale Envelope"),

typically worst case scenarios (for bird collision risk) involving the greatest rotor swept area.

3.7 Modelling outputs and the envelopes used to inform them are available for West of Duddon

Sands (RPS, 2006a) and Walney I and II (RPS, 2006b). The scenarios used in modelling for both

sites are notably different to the arrays that have actually been constructed, in both cases far

fewer turbines were constructed than had originally been proposed (and assessed in their

respective Environmental Statements). Consequently, the predicted collision risk rates of these

projects (as included in the Walney Extension HRA Report and ES Chapter 13) are significant

over-estimates.

3.8 Table 2 presents the number of turbines used in the CRMs presented in the Environmental

Statements for the West of Duddon Sands and Walney I and II offshore wind farms, and that

which was subsequently constructed. It is apparent that 3.6 MW Siemens turbines were used

in both the modelling process and subsequently then deployed at both sites.

Table 2: Walney I & II and West of Duddon Sands modelled and constructed turbine scenarios and the

resulting correction factor to be applied to the in-combination assessment.

Specification Walney I & II turbines West of Duddon Sands turbines

Rochdale Envelope modelled 152 139

As built scenario 102 108

Correction factor -32.9% -22.3%

3.9 The number of turbines constructed at Walney I and II (102) represents a 32.9% reduction from

the scenario modelled. The number of turbines being constructed at West of Duddon Sands

(108) represents a 22.3% reduction from the scenario modelled. It is assumed that a reduction

in turbines will translate into a corresponding reduction in collisions. To investigate the

relationship in the Band (2012) CRM of turbines and collision estimates experimental numbers

of turbines were entered into the model. This indicated a direct linear relationship between the

number of turbines and the collision estimates produced (i.e. if turbine number doubles,

collision risk also doubles). Therefore, for the purposes of this in-combination assessment the

predicted collision rates for Walney I&II and West of Duddon Sands are corrected by the values

given in Table 2.

3.10 Table 3 presents collisions apportioned to each SPA when Option 2 collision risk modelling is

implemented8 according to Stage A of the analysis. Option 3 results are presented in Appendix

13.1. Table 3 shows that 199 collisions per breeding season are apportioned to Morecambe

Bay SPA from projects considered to lie within Tiers 1-3 plus the Project Site. For Projects

within Tiers 1-4 (i.e. including Burbo Bank Extension) 230 collisions are apportioned to the

Morecambe Bay SPA colony.

8 A choice between options 2 and 3 is available for Burbo Bank Extension, Walney Extension and the newly

devised modelling for Barrow (Stage E).



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3.11 Thirteen collisions per breeding season are apportioned to Ribble & Alt Estuaries SPA from

projects considered to lie within Tiers 1-3 plus the Project Site. For Projects within Tiers 1-4 (i.e.

including Burbo Bank Extension) 57 collisions are apportioned to the SPA.

3.12 Fifteen collisions per breeding season are apportioned to Bowland Fells SPA from projects

considered to lie within Tiers 1-3 plus the Project Site. For Projects within Tiers 1-4 (i.e.


3.13 On day 1 of Burbo Bank Extension Issue Specific Hearing III (28th January 2014), the Examining

Authority requested clarification as to whether the analysis performed by the Applicant had

used, for those projects already operational or in-construction, the total consented capacity or

the as-built capacity. Having confirmed that it was the latter, the Applicant was asked by the

Examining Authority whether any of the built projects had ‘spare capacity’ (when comparing

consented vs as-built capacity) that might at some time in the future be built out without

further consent being required, and if that was possible then what implications this might have

for the conclusions drawn in the Applicants in-combination assessment for lesser black-backed

gull.

3.14 The consents granted for each of the relevant offshore wind farm projects have been reviewed

(sourced primarily from the DECC website9) and compared to the as-built characteristics set out

on the respective websites for each of the projects. The sites where there is potential for 'spare

capacity' to exist (based on these published sources) have been identified. For those projects

where ‘spare capacity’ theoretically exists, the as-built plans have been inspected to establish

whether it appears that the projects have been built out to the consented ‘red line area'.

3.15 However, when the areas covered by the built projects are compared to the consented red line

area, it is clear that Rhyl Flats10, Walney I and II and West of Duddon Sands have effectively

built out to the maximum permitted area (when accounting for technical or commercial

constraints). Additionally the Applicant has been advised by the Marine Management

Organisation that in principle any further development to an existing wind farm site would

require a further marine licence consent (and consultation) with a supporting assessment (Greg

Tomlinson, pers. com., dated 31/01/2014).

9 https://www.og.decc.gov.uk/EIP/pages/recent.htm

10 CRM data was not available for Rhyl Flats OWF to allow any correction of outputs



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Table 3: Estimated lesser black-backed gull breeding period collisions (CRM Option 2) at analysis Stage A for Morecambe Bay (MB), Ribble & Alt Estuaries (R&A) and

Bowland Fells (BF) SPAs

Stage Analysis description

SPA

Projects considered in-combination

Tiers 1 - 3 Tier 4 Tier 5

Walney Extension

Walney I & II

West of

Duddon

Sands

Ormonde Gwynt y Môr

Burbo Bank

Rhyl Flats

North

Hoyle

Barrow

Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon

Total

A

Population data, foraging range, and as built updates

MB 17 52 87 43 - - - - - 199 31 230 76 306

R&A 1 4 6 2 - - - - - 13 44 57 26 83

BF 2 4 6 3 - - - - - 15 18 33 24 57



March 2014 Page 9

4. Stage B : Definition of breeding period in historic CRM assessments

4.1 The collision risk to lesser black-backed gull within the breeding season presented in the West

of Duddon Sands Ornithological Impact Assessment (RPS, 2006a) is represented as summed

collisions from April to September. Throughout the assessment for Walney Extension, May to

August has been used to represent the breeding season for lesser black-backed gull having

been defined using appropriate literary sources (e.g. Wernham et al., 2002) and agreed with

Natural England. As such, in order to inform the in-combination collision risk assessment the

collision risk estimates for West of Duddon Sands are analysed to provide a revised estimate

for the likely number of collisions during the breeding season as defined for Walney Extension

(May-August).

4.2 The West of Duddon Sands Ornithological Impact Assessment presents population estimates

for lesser black-backed gull recorded within the study area during boat-based surveys between

May 2004 and September 2005. These population estimates are used to provide guidance on

the monthly number of birds at risk of collision at West of Duddon Sands. As such, the

assumption is made that a large population estimate will directly correspond with an increased

number of collisions calculated from collision risk modelling. Therefore the collision risk

estimate from the breeding season for West of Duddon Sands which is presented in Stage A is

divided proportionally based on average monthly population estimates. The number of

collisions attributed to May to August is then totalled to provide a breeding season collision

risk consistent with that used for Walney Extension.

4.3 A similar analysis had previously been conducted for Walney I & II. The analysis for Walney I

and II has been re-visited to ensure identical processes have been followed to that presented

here for West of Duddon Sands.

4.4 Table 4 presents the calculation for collisions apportioned to Morecambe Bay SPA from West

of Duddon Sands. For the period May – August (breeding period for lesser black-backed gull as

defined for Walney Extension), 56 collisions are predicted. For Walney I and II during the same

time period, 60 collisions are predicted.

4.5 It should be noted that the breeding period defined for the Ormonde Wind Farm assessment

was identical in extent to that for West of Duddon Sands and Walney I & II (ie. April -

September). However, monthly population estimates for the former site are not presented

(Ecology Consulting, 2005) so that re-definition of CRM outputs is not possible. The breeding

season collision estimates for Ormonde offshore wind farm are therefore likely to be an

overestimate.

Table 4: Calculation of breeding season collisions for lesser black-backed gull at West of Duddon Sands

Month Mean population

estimate Proportion Monthly collisions

Breeding season

collisions

April 1,193 0.17 15

May 2,100 0.31 27

56 June 210 0.03 3

July 904 0.13 11

August 1,154 0.17 15



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Month Mean population

estimate Proportion Monthly collisions

Breeding season

collisions

September 1,282 0.19 16

Total 6,843 1 87


implemented according to Stage B of the analysis. Option 3 results are indicated within

Appendix 13.1. Table 5 indicates that 168 collisions per breeding season are apportioned to

Morecambe Bay SPA from projects considered to lie within Tiers 1-3 plus the Project Site. For

Projects within Tiers 1-4 (i.e. including Burbo Bank Extension) 199 collisions are apportioned to

Morecambe Bay SPA.

4.7 Eleven collisions per breeding season are apportioned to Ribble & Alt Estuaries SPA from



4.8 Thirteen collisions per breeding season are apportioned to Bowland Fells SPA from projects





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Table 5: Estimated lesser black-backed gull breeding period collisions (CRM Option 2) at analysis Stage B for Morecambe Bay (MB), Ribble & Alt Estuaries (R&A) and



SPA



Walney Extension

Walney I & II

West of

Duddon

Sands


Burbo Bank

Rhyl Flats

North

Hoyle

Barrow

Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon

Total

B Breeding period definition

MB 17 52 56 43 - - - - - 168 31 199 76 275

R&A 1 4 4 2 - - - - - 11 44 55 26 81

BF 2 4 4 3 - - - - - 13 18 31 24 55



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5. Stage C : Apportionment of predicted collisions to source colonies

5.1 The approach taken to apportioning in the Project Environmental Statement and HRA Report

was to apportion predicted lesser black-backed gull collisions between the three SPAs within

foraging range. There are however many smaller colonies also present in the Irish Sea region

(and also within foraging range) which have the potential to be the source of lesser black-

backed gulls found offshore.

5.2 To provide a robust interpretation of the source colony of gulls deemed to be at collision risk, a

GIS tool has been developed to apportion CRM outputs to all colonies within foraging range.

The overarching methodology is in essence identical to that first detailed in Annex 2 of the HRA

Report (DONG Energy, 2013).

5.3 The collision risk estimates for each project considered in this in-combination assessment are

apportioned to colonies taking into account colony population sizes contemporaneous to the

dates of respective survey work (Table 6). Where surveys spanned more than a single year, the

year in which a full breeding season was surveyed was taken as the source data year. Where

colony data was not available for the year in question (sourced from either the JNCC SMP

database or White et al., 2013) the previous year’s colony count was used.

5.4 CRM estimates presented for Rhiannon OWF11 are based on preliminary figures presented in

the Zonal Appraisal and Planning Report (Centrica Energy, 2011). These figures were

apportioned, for the purposes of this analysis, to the three SPAs within foraging range. Further

apportioning of Rhiannon estimates to all colonies within foraging range is not attempted here.

The results for Rhiannon should therefore be noted as being precautionary and open to

significant change should an analogous apportioning approach be followed by this project.

Table 6: Boat-based ornithological survey dates for wind farms considered within the in combination

assessment of lesser black-backed gull.

Wind Farm Boat-based Survey Dates

Barrow 2008-2010

Burbo Bank Dec 2001-Feb 2002

Burbo Bank Extension 2011

Gwynt y Môr Feb 2003-March 2005

North Hoyle Jan-Dec 2001

Ormonde 2004

Rhiannon Mar 2010-Mar 2012

Rhyl Flats 2002

Walney I & II 2005

Walney Extension 2011

West of Duddon Sands 2005

11

The Rhiannon offshore wind farm project is considered as a 'Tier 5' project because, although known to the Planning Inspectorate, an application has not yet been submitted.



March 2014 Page 13


implemented according to Stage C of the analysis. Table 7 indicates that 165 collisions per

breeding season are apportioned to Morecambe Bay SPA from projects considered to lie within

Tiers 1-3 plus the Project Site. For Projects within Tiers 1-4 (i.e. including Burbo Bank Extension)

196 collisions are apportioned to Morecambe Bay SPA.

5.6 Six collisions per breeding season are apportioned to Ribble & Alt Estuaries SPA from projects



5.7 Twelve collisions per breeding season are apportioned to Bowland Fells SPA from projects





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Table 7: Estimated lesser black-backed gull breeding period collisions (CRM Option 2) at analysis Stage C for Morecambe Bay (MB), Ribble & Alt Estuaries (R&A) and



SPA



Walney Extension

Walney I & II

West of

Duddon

Sands


Burbo Bank

Rhyl Flats

North

Hoyle

Barrow

Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

C Apportionment to all colonies

MB 17 50 56 42 - - - - - 165 31 196 76 272

R&A 1 2 2 1 - - - - - 6 44 50 26 76

BF 2 4 4 2 - - - - - 12 18 30 24 54



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6. Stage D : Apportionment of predicted collisions identified in the Gwynt y Môr Appropriate

Assessment

6.1 The Appropriate Assessment for Gwynt y Môr Offshore Wind Farm (DBERR, 2008) presents an

in-combination collision assessment for lesser black-backed gull. Collision estimates are

presented for Burbo Bank, North Hoyle and Rhyl Flats Offshore Wind Farms in addition to

Gwynt y Môr itself (Table 8). Collision risk values are presented for identified lesser black-

backed gulls and also for unidentified ‘black-backed gull species’, with the latter referring to

unidentified lesser or great black-backed gulls.

6.2 As agreed with Natural England for Burbo Bank Extension (Natural England, 2013) the CRM

estimates given in DBERR (2008) can be apportioned to relevant SPAs within foraging range of

the wind farms included and then added to the in-combination assessment carried out for

Walney Extension.

Table 8: CRM predictions for Irish Sea wind farms as presented in DBERR, 2008.

LBBG LBBG +

BBG

LBBG LBBG +

BBG

LBBG LBBG +

BBG

LBBG LBBG +

BBG

LBBG LBBG +

BBG

Wind farm Gwynt y Môr North Hoyle Rhyl Flats Burbo Bank

Total No. of turbines 250 30 25 25

Avoidance rate Predicted number of collisions per year

95% 27 53 3 6 3 5 10 20 43 84

99% 5 11 1 1 1 1 2 4 9 17

99.5% 3 5 0 1 0 1 1 2 4 9

99.9% 1 1 0 0 0 0 0 0 1 1

LBBG = lesser black-backed gull

BBG = Unidentified black backed gull species

6.3 Avoidance rates presented in DBERR (2008) did not include a 98% level as currently preferred

as the default rate by Natural England and JNCC. CRM predictions at 98% were calculated in

the following analysis alongside a partitioning exercise to account for the proportion of great

black-backed gulls within the values presented in Table 8. It also should be noted that the CRM

predictions in DBERR (2008) is presented on an annual basis rather than breeding season.

Without comprehensive monthly population data as used for Walney I & II and West of

Duddon Sands (Stage B of this Paper's analysis) a correction cannot be made with any degree

of certainty. It is therefore highlighted that the CRM rates taken forward from the DBERR

(2008) are highly precautionary and a likely overestimate.

6.4 To inform a partitioning exercise to correct for the presence of great black-backed gull in the

DBERR (2008) predictions, assessment and monitoring publications were consulted to source

appropriate data. The Environmental Statement for Gwynt y Môr (Npower Renewables,

2006a) presents data relating to the number of birds observed in flight. Surveys were

undertaken between February 2003 and March 2005 with data from June 2003 and March

2005 being used within the Appropriate Assessment. Flight height data was recorded for 385



March 2014 Page 16

lesser black-backed gulls and 262 great black-backed gulls. The values to be used to apportion

the collision risk attributed to lesser black-backed gull only are shown in Table 9.

Table 9: Partitioning values for black-backed gulls at Gwynt y Môr.

Species No. of birds Proportion

Lesser black-backed gull 385 0.6

Great black-backed gull 262 0.4

6.5 Data relating to the number of lesser black-backed gull and great black-backed gull at North

Hoyle are presented in the 2004-05 and 2005-06 monitoring reports for the site (Npower

Renewables, 2006b; Npower Renewables 2007). The combined data from these two data sets

and the resulting gull proportions are shown in Table 10.

Table 10: Partitioning values for black-backed gulls at North Hoyle.




6.6 The Rhyl Flats 2005-07 monitoring report (ESS Ltd., 2007) contains data relating to the number

of lesser black-backed gull and great black-backed gull observed in flight. These data and the

calculated proportions to be applied to collision risk estimates in the DBERR (2008) are shown

in Table 11.

Table 11: Partitioning values for black-backed gulls at Rhyl Flats.




6.7 Data relating to the number of lesser black-backed gull and great black-backed gull at Burbo

Bank is taken from Seascape Energy Ltd. (2002). These data and the calculated proportions to

be applied to collision risk estimates in DBERR (2008) are shown in Table 12.

Table 12: Partitioning values for black-backed gulls at Burbo Bank.




6.8 The overall collision estimates for lesser black-backed gull from the four sites included in

DBERR (2008) are shown in Table 13. These values are at 98% avoidance and include

partitioned ‘black-backed gulls’ using the portioning approach and data described above.



March 2014 Page 17

Table 13: Collision risk at 98% avoidance rate for lesser black-backed gull from Gwynt y Môr, North

Hoyle, Rhyl Flats and Burbo Bank (Stage D)

Wind farm Lesser black-backed gull

collisions

Partitioned black-backed

gull collisions Total collisions

Gwynt y Môr 10.8 6.2 17 (11)

North Hoyle 1.2 0.7 2

Rhyl Flats 1.2 0.5 2

Burbo Bank 4.0 1.4 5

6.9 The built Gwynt y Môr turbine scenario was considerably reduced to that assessed in DBERR

(2008). Correction for this discrepancy was undertaken in line with the process implemented in

Stage A for Walney I&II and West of Duddon Sands. The Gwynt y Môr project has not however

been built out to the full red line area as established for Walney I & II and West of Duddon

Sands in Stage A. It is evident that a part of the consented area to the north-west of Gwynt y

Môr is currently undeveloped. This analysis uses the data on LBBG at the Gwynt y Môr site

from the Appropriate Assessment document but also adjusts for the as built 576MW capacity.

Total breeding season collisions for the as built Gwynt y Môr offshore wind farm are therefore

considered to be 11 birds per annum, compared to 17 birds per annum for the full 250 turbine

750MW modelled scenario (Table 13).

6.10 These results are carried forward to Table 14 as part of the in-combination assessment. This

demonstrates that in the case of the Morecambe Bay SPA there would be an increase

apportionment of a single gull mortality for the full 750MW capacity. The results indicate that

even in the event that a further 90 turbines were installed (which would not be possible in the

space remaining within the consented area) the implications would not, lead to a material

change in the conclusions of the in-combination assessment. A similar effect is applied to

Ribble & Alt Estuaries SPA where a single collision would be added for each breeding season for

the full 750MW capacity. No change to collision rates apportioned to Bowland Fells SPA are

anticipated.


implemented according to Stage D of the analysis. Table 14 indicates that 174 collisions per

breeding season are apportioned to Morecambe Bay SPA from projects considered to lie within

Tiers 1-3 plus the Project Site. For Projects within Tiers 1-4 (i.e. including Burbo Bank Extension)

205 collisions are apportioned to Morecambe Bay SPA.

6.12 Eleven collisions per breeding season are apportioned to Ribble & Alt Estuaries SPA from



6.13 Seventeen collisions per breeding season are apportioned to Bowland Fells SPA from projects





March 2014 Page 18

Table 14: Estimated lesser black-backed gull breeding period collisions (CRM Option 2) at analysis Stage D for Morecambe Bay (MB), Ribble & Alt Estuaries (R&A) and



SPA



Walney Extension

Walney I & II

West of

Duddon

Sands


12

Burbo Bank

Rhyl Flats

North

Hoyle

Barrow

Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

D

Apportionment of CRM figures in DBERR (2008)

MB 17 50 56 42 5 (6) 2 1 1 - 174 31 205 76 281

R&A 1 2 2 1 3 (4) 2 0 0 - 11 44 55 26 81

BF 2 4 4 2 2 1 1 1 - 17 18 35 24 59

12

Gwynt y Môr figures for full 750MW capacity are given in parentheses



March 2014 Page 19

7. Stage E : CRM for Barrow OWF using post-construction monitoring data

7.1 Following the request of Natural England in Issue Specific Hearing III for Burbo Bank Extension,

a collision risk modelling (CRM) exercise for Barrow Offshore Wind Farm (OWF) was

undertaken to inform the in-combination assessment for lesser black-backed gull at the

proposed Burbo Bank Extension offshore wind farm. In response to the Applicant's scope for

this assessment Natural England suggested (Natural England, 2013) that the CRM should:

“Refer to post-construction monitoring (PCM ) data from the OWF. This spans three years and

allows mean densities of LBBGs to be used in a Band Option 2 collision risk model. We are only

concerned with estimates of collision in the breeding season. The approach uses empirical data

from the OWF and makes fewest assumptions. It also inherently incorporates changes in colony

size as data were collected recently (2008-2010), and can reflect an ‘as built’ development

scenario.”

7.2 This analysis is carried forward in order to inform the in-combination assessment presented in

this paper.

7.3 The CRM utilised data collected as part of post-construction monitoring surveys at Barrow

Offshore Wind Farm between 2008 and 2010 (reported in NIRAS Consulting 2013b). Within the

breeding season for lesser black-backed gull, data was available for July and August 2008, May

and August 2009 and May, July and August 2010. Every month, with the exception of June, was

surveyed more than once. As such, an mean monthly density was calculated for use in the

Band (2012) CRM. As no surveys were undertaken in June, the average densities from May and

July provided a proxy density. The densities as used in the CRM are shown in Table 15.

Table 15: Mean monthly densities of lesser black-backed gull as used for the CRM for Barrow OWF

Month May June July August

Density (km2) 1.14 1.16 1.17 0.42

7.4 Biometric data for lesser black-backed gull were consistent with that used in the CRM for

Walney Extension within the HRA Report and Environmental Statement. Data relating to

Barrow OWF for use in the CRM was provided by BoWind and are presented in Table 16. The

monthly proportion of time that turbines will be operational, as advised by BoWind is

presented in Table 17.

Table 16: Barrow Offshore Wind Farm and turbine parameters used in collision risk modelling

Wind farm parameters

Latitude 53.99

Number of turbines 30

Turbine parameters

No. of blades 3

Rotation speed (rpm) 16.1

Rotor radius (m) 45

Hub height (m) 80



March 2014 Page 20

Max blade width (m) 3.512

Pitch (o) 6

Table 17: Monthly turbine operational time as used in the CRM for Barrow OWF

Month May Jun Jul Aug

Monthly proportion of time operational (%) 84 83 86 81

7.5 The breeding season collision risk modelling results for Barrow OWF using post-construction

monitoring data are shown in Table 18. At 98% avoidance 25 collisions / breeding season are

predicted with option 2, while option 3 predicts 15 collisions / breeding season.

Table 18: CRM results for Barrow OWF using post-construction monitoring data (collisions/breeding

season)

Avoidance rate (%) Option 2 Option 3

No avoidance 1,263 767

95 63 38

98 25 15

99 13 8

99.5 6 4


implemented according to Stage E of the analysis. The CRM results for Barrow OWF given in

Table 18 are apportioned to each SPA; at 98% avoidance 22 of the 25 predicted Option 2

collisions are apportioned to Morecambe Bay SPA.

7.7 Table 19 indicates that 196 total collisions per breeding season are apportioned to Morecambe

Bay SPA from projects considered to lie within Tiers 1-3 plus the Project Site. For Projects

within Tiers 1-4 (i.e. including Burbo Bank Extension) 227 collisions are apportioned to

Morecambe Bay SPA.

7.8 Twelve collisions per breeding season are apportioned to Ribble & Alt Estuaries SPA from



7.9 Eighteen collisions per breeding season are apportioned to Bowland Fells SPA from projects





March 2014 Page 21

Table 19: Estimated lesser black-backed gull breeding period collisions (CRM Option 2) at analysis Stage E for Morecambe Bay (MB), Ribble & Alt Estuaries (R&A) and



SPA



Walney Extension

Walney I & II

West of

Duddon

Sands


13

Burbo Bank

Rhyl Flats

North

Hoyle

Barrow

Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

E

Apportionment of Barrow

CRM

MB 17 50 56 42 5 (6) 2 1 1 22 196 31 227 76 303

R&A 1 2 2 1 3 (4) 2 0 0 1 12 44 56 26 82

BF 2 4 4 2 2 1 1 1 1 18 18 36 24 60

13




March 2014 Page 22

8. Stage F : Collision risk tracking breeding population size

8.1 Stage F relates to the adjustment of historic CRM estimates to account for colony size changes

between the time of the baseline surveys to current estimates. This analysis makes the

assumption that colony size has a direct relationship with the density of birds at sea and

corrects previously presented CRM results to account for this projected change in density.

8.2 Stage F includes re-assessment of CRM estimates from the following consented projects:

Gwynt y Môr, North Hoyle, Ormonde, Rhyl Flats, Walney I & II and West of Duddon Sands. The

lesser black-backed gull population size for each of the three SPAs considered in this paper

was determined for each year between 2001 and 2012. This time period was delineated by the

year best representing the oldest pre-application surveys, and the latest census data available

via the JNCC SMP database. Where counts were not available for a year, the data was

extrapolated where possible or most recent count of a previous year used.

8.3 A collision risk conversion rate was calculated for each offshore wind farm by dividing the

number of collisions by each of the SPAs population size at the time of the pre-application

baseline surveys (or post-construction in the case of Barrow). For any other year, the calculated

number of collisions apportioned to a SPA is considered to be the latter’s population size for

the year multiplied by the respective collision risk conversion rate. For each combination of

offshore wind farm and SPA the number of collisions was calculated initially for the year 2011.

The latter year has been used in this in-combination assessment of offshore wind farms as that

contemporaneous with the Project site specific summer surveys (summer 2011). The calculated

number of collisions apportioned to a SPA was summed to provide a total for the year 2011 for

those offshore wind farms considered in combination for Tiers 1-5. When providing its view on

this assessment for Burbo Bank Extension, Natural England (23th January 2014) recommended

the Applicant revised the collision risk tracking of breeding populations of lesser black-backed

gulls with the addition of two survey datasets from 2012.

8.4 The 2012 datasets refer to West of Duddon Sands and Walney I & II wind farms where data has

been extracted from a West of Duddon Sands Pre-construction Monitoring Report (DONG

Energy/Scottish Power Renewables 2013) and a post-construction report for Walney I & II

Offshore Wind Farm (DONG Energy, 2013c).

8.5 In order to underpin the validity of undertaking CRM tracking of breeding populations of lesser

black-backed gulls whilst also describing the relationship, research was undertaken that

compared the Morecambe Bay SPA population with offshore density of this species at various

adjacent offshore wind farm projects. Densities used were from Project specific boat-based

surveys during the breeding season (May - August) at four offshore wind farms (Barrow,

Walney Extension, Walney I & II and West of Duddon Sands) situated in waters within 17 km of

the South Walney colony within Morecambe Bay SPA (Barrow Offshore Wind Limited 2012, RPS

2006, Walney Offshore Windfarm 2012, Walney Offshore Extension Windfarm, 2013). The

species mean-maximum foraging range is 141 km (Thaxter et al., 2012) although on a

precautionary basis only those Projects adjacent to South Walney were analysed in order to

prevent undue influence from other colonies.



March 2014 Page 23

8.6 The survey data assessed were from the time period 2004 – 2012 and depending upon the

wind farm, are from surveys conducted before, during and after construction of the

development (see Appendix 13.3). For a given year and wind farm, survey data were only used

in this analysis where two or more surveys exist, increasing the expectation that the data

provide a more representative sample of offshore density for this species.

8.7 Figure 1 presents, for each year, the mean for all sites of the mean density recorded for lesser

black-backed gulls at sea together with the breeding population size at Morecambe Bay SPA.

Where the mean density of lesser black-backed gull is only available for a combination of

breeding seasons, i.e. for Walney I & II, the statistic provided is used across all years surveyed.

The relationship for lesser black-backed gull between its breeding population size at

Morecambe Bay SPA and mean density recorded at sea is further explored through the use of

an exponential regression analysis, presented in Figure 2. This analysis suggests 56% of the

variation (R2 = 55.52%) can be explained by this exponential regression. In other words, the

data collected implies that the reduction in the Morecambe Bay SPA population has reduced

the at sea density at adjacent wind farms sites in the Irish Sea. This supports the Applicant's

Stage F adjustment of CRM values to track the reduction of the lesser black-backed gull

breeding population at the south Walney colony.

Figure 1: Lesser black-backed gull density at offshore wind farm sites against the Morecambe Bay SPA

population size

0

1

2

3

4

5

6

7

8

9

10

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

1998 2000 2002 2004 2006 2008 2010 2012

Mea

n f

or

all s

ites

of

mea

n s

ite

den

sity

Mo

reca

mb

e B

ay S

PA p

op

ula

tio

n s

ize

Year

Morecambe Bay SPAPopulation

All sites



March 2014 Page 24

Figure 2: Lesser black-backed gulls density at offshore wind farm sites against the Morecambe Bay

SPA population size

In the Issue Specific Hearing III for Burbo Bank Extension, Natural England stated the following with

regards to Stage F:

‘We agree that the adjustment of collisions to account for colony changes at South Walney is

now justified based on best available evidence. As per the amended Appendix 9 submitted to

PINS on 27 Jan 2014, the Applicant has used the best available evidence including data

provided by Natural England, and we agree the adjustments made are appropriate for collisions

apportioned to Morecambe Bay SPA. Collisions apportioned to Bowland Fells SPA have also

been adjusted appropriately as this colony has experienced similar declines. However, as the

Ribble & Alt Estuaries SPA gull colony has not declined, we do not advise applying Stage F to

collisions apportioned to this colony. Applying Stages A – E and G is considered appropriate’.

8.8 Table 20 presents the implications of applying tracking of the breeding population to historic

CRM estimates for lesser black-backed gull (Stage F). This adjustment has been applied to all

Tier 1 - 3 sites (except the Project site). Table 20 indicates that 100 collisions per breeding

season are apportioned to Morecambe Bay SPA from projects considered to lie within Tiers 1-3

plus the Project Site. For Projects within Tiers 1-4 (i.e. including Burbo Bank Extension) 131

collisions are apportioned to Morecambe Bay SPA.

8.9 Nine collisions per breeding season are apportioned to Bowland Fells SPA from projects



y = 0.1185e0.0001x

R² = 0.5552

0

0.5

1

1.5

2

2.5

3

0 5000 10000 15000 20000 25000 30000

Den

sity

at

sea

(bir

ds/

km2

)

Morecambe Bay SPA population size (no. of birds)

Exponential regression



March 2014 Page 25

Table 20: Estimated lesser black-backed gull breeding period collisions (CRM Option 2) at analysis Stage F for Morecambe Bay (MB), Ribble & Alt Estuaries (R&A) and



SPA



Walney Extension

Walney I & II

West of

Duddon

Sands


14

Burbo Bank

Rhyl Flats

North

Hoyle

Barrow

Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

F

CRM tracking breeding

population

MB 17 23 26 17 2 (3) 0 0 0 15 100 31 131 76 207

R&A Considered not applicable by Natural England

BF 2 2 2 1 1 0 0 0 1 9 18 27 24 51

14




March 2014 Page 26

9. Stage G : Population age structure

9.1 Collision risk modelling undertaken for the Project was undertaken using density data of all

lesser black-backed gulls recorded. Breeding adults are the most relevant aspect of the species

population in terms of this assessment; the breeding lesser black-backed gull qualifying

features of each of the three SPAs considered refer to the number of adult birds present. A

limited level of age class identification was undertaken within boat-based surveys of the

Project site where a minimum of 15% of lesser black-backed gulls recorded in the breeding

season referred to juvenile or sub-adult birds. Limited data are available from the other wind

farms considered in this assessment regarding gull age structure within their respective

baseline surveys (no differentiation of ages was made for Burbo Bank Extension for example).

9.2 Lesser black-backed gulls tend to first breed at four years of age (Cramp & Simmons, 2004)

which implies that a significant proportion of the population of this species does not contribute

to breeding on an annual basis. The Habitat Regulations Assessment of the now consented

Galloper Offshore Wind Farm (SSE Renewables / RWE Npower Renewables, 2011) investigated

the age structure of lesser black-backed gulls and sub-adult non-breeders were discounted

from the CRM. Age structure data were available to assign a proportion of the population that

was not part of the breeding population. From March to July the data were heavily skewed

towards adult birds (c.80%), with the proportion highest during June and July. These data

support the analysis from Walney Extension in that a proportion of 15-20% of individuals

recorded in the breeding season are likely to be non-breeding birds. Further supporting

evidence for this approach is given in the Habitats Regulations Assessment for East Anglia One

(SSE Renewables, 2012) which found that 78% of lesser black-backed gulls were adults. Sub-

adult or juvenile gulls were not considered within collision risk modelling of this site.

9.3 stage G of the analysis therefore provides a precautionary correction of 15% of the CRM

estimates to all sites considered, in order to account for the element of non-breeding birds

within the population. This correction was agreed to be suitably precautionary with Natural

England during Issue Specific Hearing III for Burbo Bank Extension.

9.4 Table 21 indicates that 85 collisions per breeding season are apportioned to Morecambe Bay

SPA from projects considered to lie within Tiers 1-3 plus the Project Site when Stage G is

applied. For Projects within Tiers 1-4 (i.e. including Burbo Bank Extension) 111 collisions are

apportioned to Morecambe Bay SPA.

9.5 Twelve collisions per breeding season are apportioned to Ribble & Alt Estuaries SPA from



9.6 Nine collisions per breeding season are apportioned to Bowland Fells SPA from projects





March 2014 Page 27

Table 21: Estimated lesser black-backed gull breeding period collisions (CRM Option 2) at analysis Stage G for Morecambe Bay (MB), Ribble & Alt Estuaries (R&A) and


Stage Description SPA



Walney Extension

Walney I & II

West of

Duddon

Sands


15

Burbo Bank

Rhyl Flats

North

Hoyle

Barrow

Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

G

Correction for

immature birds

MB 14 20 22 14 2 (3) 0 0 0 13 85 26 111 76 187

R&A 1 2 2 1 3 (4) 2 0 0 1 12 37 49 26 75

BF 2 2 2 1 1 0 0 0 1 9 15 24 24 48

15




March 2014 Page 28

10. Potential Biological Removal

10.1 The various analysis stages presented in this paper are related in this section to PBR thresholds

and examination of the associated f value as given in Table 1. The context behind this

presentation is that f is a continuous spectrum from 1 to 0, and presentation in this way allows

greater insight into potential effects. The tables presented below represent all collisions

estimates using (where applicable) Option 2 outputs; Option 3 results are shown in Appendix

13.2.

Morecambe Bay SPA

10.2 Table 22 presents PBR f values for Morecambe Bay SPA considering each analytical stage of this

Paper and also the JNCC and Natural England tiered approach. Following all Stages of the Paper

through to G, the in-combination collision estimate for lesser black-backed gull for projects

included in Tiers 1-3 (i.e. 85 adults / breeding season presented in Table 21) represents f =

0.085. For Tiers 1-4 the in-combination collision estimate of 111 adults / breeding season

represents f = 0.111.

Table 22: Matrix of PBR f values for Option 2 collisions apportioned to Morecambe Bay SPA

Analysis Stage Tiers 1-3 (including

Walney Extension) Tiers 1-4 Tiers 1-5

A 0.199 0.229 0.305

B 0.168 0.199 0.274

C 0.165 0.196 0.271

D 0.174 0.205 0.280

E 0.196 0.226 0.302

F 0.010 0.131 0.207

G 0.085 0.111 0.187

Ribble & Alt Estuaries SPA

10.3 Table 23 presents PBR f values for Ribble & Alt Estuaries SPA considering each analytical stage

of this Paper and also the JNCC and Natural England tiered approach. Following all Stages of

the Paper through to G, the in-combination collision estimate for lesser black-backed gull for

projects included in Tiers 1-3 (i.e. 12 adults / breeding season as presented in Table 21)

represents f = 0.024. For Tiers 1-4 the in-combination collision estimate of 49 adults / breeding

season represents f = 0.097. These values assume the removal of Stage F for this SPA.

Table 23: Matrix of PBR f values for Option 2 collisions apportioned to Ribble & Alt Estuaries SPA

Analysis Level Tiers 1-3 (including


A 0.026 0.112 0.164

B 0.022 0.108 0.160

C 0.012 0.099 0.150

D 0.022 0.108 0.160



March 2014 Page 29



E 0.024 0.110 0.162

F Considered not applicable by Natural England

G 0.024 0.097 0.148

Bowland Fells SPA

10.4 Table 24 presents PBR f values for Bowland Fells SPA considering each analytical stage of this

Paper and also the JNCC and Natural England tiered approach. Following all Stages of the Paper

through to G, the in-combination collision estimate for lesser black-backed gull for projects

included in Tiers 1-3 (i.e. 9 adults / breeding season as presented in Table 21) represents f =

0.013. For Tiers 1-4 the in-combination collision estimate of 24 adults / breeding season

represents f = 0.036.

Table 24: Matrix of PBR f values for Option 2 collisions apportioned to Bowland Fells SPA



A 0.022 0.049 0.085

B 0.019 0.046 0.082

C 0.018 0.045 0.080

D 0.025 0.052 0.088

E 0.027 0.053 0.089

F 0.013 0.040 0.076

G 0.013 0.036 0.071



March 2014 Page 30

11. Conclusion

11.1 This report has presented seven analytical stages (levels A – G) investigating the in-combination

lesser black-backed gull collision risk to Morecambe Bay, Ribble and Alt Estuaries and Bowland

Fells SPAs.

11.2 Collision estimates at each analytical level were related to PBR outputs and are presented to

take account of the tiered approach to in-combination assessment as detailed by Natural

England and JNCC (2013). The analysis is considered to include considerable precaution at all

stages of the assessment. Identified areas where precaution / potential overestimation of

collision effects include the following:

The constructed turbine scenarios for the Project Site and Burbo Bank are likely to

involve a fewer number of larger turbines than assessed here. This will result in a

smaller ‘risk window’ within which collisions are possible compared to the design

envelope assessed in the Environmental Statement.

Collision estimates for Ormonde are based on a broad six month definition for the

breeding period which contrasts with the agree and more accurately defined breeding

season used in analysis of the Project Site. Appropriate data for the Ormonde offshore

wind farm have not be found to be available to correct CRM figures to the refined

lesser black-backed gull breeding season definition. However if the same effect was

applied as determined for West of Duddon Sands it would imply that 37% of collisions

at Ormonde lie outside of the agreed breeding season.

Collision estimates presented in DBERR (2008) are given for the annual cycle. Data

could not be sourced to provide a correction for the agreed breeding season.

However, again if the correction for West of Duddon Sands is taken into consideration

a figure significantly higher than 37% of collisions are likely to be outside of the

breeding season for Gwynt y Môr, Rhyl Flats, Burbo Bank and North Hoyle.

Analysis of Stage F suggests an exponential relationship between colony size and

density at sea may be highly precautionary. The data collected implies that the

reduction in Morecambe Bay SPA population has had a disproportionately negative

effect of at sea density at adjacent wind farms sites in the Irish Sea.

The collision risk values used in this report, that are calculated using the Band (2012)

CRM, are focussed on Option 2 of that model as requested by Natural England.

However, the Applicant maintains that Option 3 provides the most mathematically

advanced model available and its use remains valid. As such, the assessment

incorporating results from Option 3, where applicable16, is presented in Appendices

13.1 and 13.2. For Morecambe Bay SPA, 86 breeding adults at risk of collision using

16

Option 3 results are available for Barrow, Burbo Bank Extension and Walney Extension



March 2014 Page 31

Option 3 estimates for projects within Tiers 1-4 (compared to 111 for Option 2

modelling). Comparable figures for Ribble & Alt Estuaries SPA and Bowland Fells SPA

are 29 and 15 adult Option 3 collisions per breeding season (compared to 49 and 24

Option 2 collisions respectively) (Appendix 13.1).

Collision figures for Rhiannon are estimates based on published ZAP data (Centrica

Energy 2011) and are unrefined with the exception of simple apportioning to the three

SPAs (i.e. Other gull colonies were not considered). The Rhiannon project has not yet

published its assessment and the values presented here can only be considered

provisional and precautionary at this stage.

11.3 Option 2 collisions apportioned to Morecambe Bay SPA represent an f value of between 0.085

(Tiers 1 – 3) and 0.111 (Tiers 1-4). In using Option 3 outputs for the Project Site, Burbo Bank

Extension and Barrow collisions apportioned to Morecambe Bay SPA represent an f value of

between 0.073 (Tiers 1 – 3) and 0.086 (Tiers 1-4).

11.4 Option 2 collisions apportioned to Ribble & Alt Estuaries SPA represent an f value of between

0.024 (Tiers 1 – 3) and 0.097 (Tiers 1-4). In using Option 3 outputs for the Project Site, Burbo

Bank Extension and Barrow collisions apportioned to Morecambe Bay SPA represent an f value

of between 0.022 (Tiers 1 – 3) and 0.057 (Tiers 1-4).

11.5 Option 2 collisions apportioned to Bowland Fells SPA represent an f value of between 0.013

(Tiers 1 – 3) and 0.036 (Tiers 1-4). In using Option 3 outputs for the Project Site, Burbo Bank

Extension and Barrow collisions apportioned to Morecambe Bay SPA represent an f value of

between 0.010(Tiers 1 – 3) and 0.022 (Tiers 1-4).

11.6 This analysis supports a conclusion of "no adverse effect" on the breeding lesser black-backed

gull interest feature of the Morecambe Bay, Ribble and Alt Estuaries, and Bowland Fells SPAs

for the Project alone and in-combination with other projects.



March 2014 Page 32

12. References

Band, B., 2012. Using a collision risk model to assess bird collision risks for offshore wind farms –

with extended method. Report to Strategic Ornithological Support Services, March 2012.

Barrow Offshore Wind Farm Limited, 2012. Post Construction Ornithological Monitoring – Third

Year Report and Overall Conclusions. Barrow Offshore Wind Farm Limited.

Centrica Energy, 2011. Irish Sea Zone Zonal Appraisal and Planning Report : Chapter 13

Ornithology.

DBERR, 2008. Appropriate Assessment with regard to Gwynt y Môr. Department for Business

Enterprise & Regulatory Reform.

Dillingham, P.W. and Fletcher, D. (2008) ‘Estimating the ability of birds to sustain additional

human-caused mortalities using a simple decision rule and allometric relationships’, Biological

Conservation, 141, pp. 1783-1792.

DONG Energy, 2013. Walney Extension offshore wind farm Habitats Regulations Assessment

DONG Energy, 2013a. Burbo Bank Extension Clarification Note: Lesser black-backed gull feature of

Morecambe Bay SPA. NIRAS Consulting Ltd report to DONG Energy.

DONG Energy, 2013b. Walney Extension Clarification Note: SPA apportioning and PBR analysis.

NIRAS Consulting Ltd report to DONG Energy.

DONG Energy, 2013c Walney I & II, post construction monitoring report.

DONG Energy, 2014a. Burbo Bank Extension: Appendix 9 – lesser black-backed gull collision risk

modelling. An update to the in-combination assessment. Amendment 27th January 2014. NIRAS

Consulting Ltd report to DONG Energy.

DONG Energy, 2014b. Burbo Bank Extension: Appendix 7 – updated lesser black-backed gull in-

combination collision risk assessment, following questions related to Issue Specific Hearing #3,

including apportioning of colony data. NIRAS Consulting Ltd report to DONG Energy.

DONG Energy, 2014c. Walney Extension Clarification Note: Collision risk modelling options and

potential collision height - updated. NIRAS Consulting Ltd report to DONG Energy, January 2014.

DONG Energy/Scottish Power Renewables 2013 West of Duddon Sands pre-construction monitoring

report

ESS Ltd. (2007). Rhyl Flats Offshore Wind Farm: Annual FEPA Monitoring Report (2005-6). Interim

report to RWE Group.

JNCC and Natural England, 2013a. JNCC and Natural England Suggested Tiers for Cumulative Impact

Assessment.



March 2014 Page 33

JNCC, 2013. Seabird Population Trends and Causes of Change: 1986-2012 Report (http://www.jncc.defra.gov.uk/page-3201). Joint Nature Conservation Committee. Updated July 2013

Natural England, 2013. Natural England views on revised assessment of lesser black-backed gull

collision mortality in the Irish Sea – in relation to Burbo Bank Extension OWF.

NIRAS Consulting, 2013a. Burbo Bank Extension Offshore Wind Farm Clarification Note: lesser

black-backed gull feature of Morecambe Bay SPA. Cambridge: NIRAS Consulting Ltd.

NIRAS Consulting, 2013b. Burbo Bank Extension Offshore Wind Farm Scope of Works: Further consideration of lesser black-backed gull Morecambe Bay SPA. Cambridge: NIRAS Consulting Ltd.

NIRAS Consulting, 2013c. Barrow Offshore Wind Farm: Post Construction Boat-based Ornithological Monitoring –Third Year Report and Overall Conclusions. Cambridge: NIRAS Consulting Ltd.

Npower Renewables, 2006a. Gwynt y Môr Offshore Wind Farm: Environmental Statement.

Npower Renewables, 2006b. North Hoyle Offshore Wind Farm: Ornithological Monitoring 2004-

2005.

Npower Renewables 2007. North Hoyle Offshore Wind Farm: Ornithological Monitoring 2005-2006.

RPS, 2006a. West of Duddon Sands Offshore Windfarm Ornithological Impact Assessment. St Ives:

RPS.

RWE Npower & SSE Renewables, 2011. Galloper Wind Farm Project: Habitats Regulations

Assessment Report.

Seascape Energy Ltd., 2002. Burbo Offshore Wind Farm – Ornithology Final Report.

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Thaxter, C.B., Lascelles, B., Sugar, K., Cook, A.S.C.P., Roos, S., Bolton, M., Langston, R.H.W. and

Burton, N.H.K., 2012. Seabird foraging ranges as a preliminary tool for identifying candidate Marine

Protected Areas. Biological Conservation 156, 53-61.

Walney Offshore Windfarm, 2012. Walney Construction Boat-based Bird Monitoring Report.

Walney Offshore Windfarm.

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Statement Chapter 13 Offshore Ornithology. DONG Energy Walney Extension (UK) Ltd..

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http://www.jncc.defra.gov.uk/page-3201



March 2014 Page 34

13. Appendices

Appendix 13.1: Full CRM results for Options 2 and 3

Morecambe Bay SPA (using Band (2012) CRM Option 2)

Stage Description



Walney Extension

Walney I & II

West of Duddon Sands


Burbo Bank

Rhyl Flats

North Hoyle

Barrow Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

A

Population, foraging range & as built updates

17 52 87 43 - - - - - 199 31 230 76 306


17 52 56 43 - - - - - 168 31 199 76 275


17 50 56 42 - - - - - 165 31 196 76 272

D Apportionment of CRM in DBERR (2008)

17 50 56 42 5 (6) 2 1 1 - 174 31 205 76 281

E Apportionment of Barrow CRM

17 50 56 42 5 (6) 2 1 1 22 196 31 227 76 303

F CRM tracking breeding population

17 23 26 17 2 (3) 0 0 0 15 100 31 131 76 207

G Correction for immature birds

14 20 22 14 2 (3) 0 0 0 13 85 26 111 76 187



March 2014 Page 35

Morecambe Bay SPA (using Band (2012) CRM option 3) (wind farms in italics have Option 3 results available)

Stage Description



Walney Extension

Walney I & II



Burbo Bank

Rhyl Flats

North Hoyle

Barrow Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

A


8 52 87 43 - - - - - 190 15 205 76 281


8 52 56 43 - - - - - 159 15 174 76 250


8 50 56 42 - - - - - 156 15 171 76 247


8 50 56 42 5 (6) 2 1 1 - 165 15 180 76 256


8 50 56 42 5 (6) 2 1 1 13 178 15 193 76 269


8 23 26 17 2 (3) 0 0 0 9 85 15 100 76 176


7 20 22 14 2 (3) 0 0 0 8 73 13 86 76 162



March 2014 Page 36

Ribble & Alt Estuaries SPA (using Band (2012) CRM Option 2)

Stage Description



Walney Extension

Walney I & II



Burbo Bank

Rhyl Flats

North Hoyle

Barrow Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

A


1 4 6 2 - - - - - 13 44 57 26 83


1 4 4 2 - - - - - 11 44 55 26 81


1 2 2 1 - - - - - 6 44 50 26 76


1 2 2 1 3 (4) 2 0 0 - 11 44 55 26 81


1 2 2 1 3 (4) 2 0 0 1 12 44 56 26 82


Considered not applicable by Natural England


1 2 2 1 3 (4) 2 0 0 1 12 37 49 26 75



March 2014 Page 37

Ribble & Alt Estuaries SPA (using Band (2012) CRM option 3) (wind farms in italics have Option 3 results available)

Stage Description



Walney Extension

Walney I & II



Burbo Bank

Rhyl Flats

North Hoyle

Barrow Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

A


1 4 6 2 - - - - - 13 21 34 26 60


1 4 4 2 - - - - - 11 21

32 26 58


1 2 2 1 - - - - - 6 21

27 26 53


1 2 2 1 3 (4) 2 0 0 - 11 21

32 26 58


1 2 2 1 3 (4) 2 0 0 0 11 21

32 26 58


Considered not applicable by Natural England


1 2 2 1 3 (4) 2 0 0 0 11 18 29 26 55



March 2014 Page 38

Bowland Fells SPA (using Band (2012) CRM Option 2)

Stage Description



Walney Extension

Walney I & II



Burbo Bank

Rhyl Flats

North Hoyle

Barrow Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

A


2 4 6 3 - - - - - 15 18 33 24 57


2 4 4 3 - - - - - 13 18 31 24 55


2 4 4 2 - - - - - 12 18 30 24 54


2 4 4 2 2 1 1 1 - 17 18 35 24 59


2 4 4 2 2 1 1 1 1 18 18 36 24 60


2 2 2 1 1 0 0 0 1 9 18 27 24 51


2 2 2 1 1 0 0 0 1 9 15 24 24 48



March 2014 Page 39

Bowland Fells SPA (using Band (2012) CRM option 3) (wind farms in italics have Option 3 results available)

Stage Description



Walney Extension

Walney I & II



Burbo Bank

Rhyl Flats

North Hoyle

Barrow Sub-Total

Burbo Bank

Extension

Sub-Total

Rhiannon Total

A


1 4 6 3 - - - - - 14 9 23 24 47


1 4 4 3 - - - - - 12 9 21 24 45


1 4 4 2 - - - - - 11 9 20 24 44


1 4 4 2 2 1 1 1 - 16 9 25 24 49


1 4 4 2 2 1 1 1 0 16 9 25 24 49


1 2 2 1 1 0 0 0 0 7 9 16 24 40


1 2 2 1 1 0 0 0 0 7 8 15 24 39



March 2014 Page 40

Appendix 13.2: PBR matrices using Option 3 CRM outputs

Morecambe Bay SPA Option 3

Analysis Level Tiers 1-3 (including Walney Extension)

Tiers 1-4 Tiers 1-5

A 0.190 0.205 0.280

B 0.159 0.174 0.249

C 0.156 0.171 0.246

D 0.165 0.193 0.255

E 0.178 0.193 0.268

F 0.085 0.100 0.176

G 0.073 0.086 0.162

Ribble & Alt Estuaries SPA Option 3


Tiers 1-4 Tiers 1-5

A 0.026 0.067 0.118

B 0.022 0.063 0.114

C 0.012 0.053 0.105

D 0.022 0.063 0.114

E 0.022 0.063 0.114

F Considered not applicable by Natural England

G 0.022 0.057 0.108

Bowland Fells SPA Option 3


Tiers 1-4 Tiers 1-5

A 0.021 0.034 0.070

B 0.018 0.031 0.067

C 0.016 0.030 0.065

D 0.024 0.037 0.073

E 0.024 0.037 0.073

F 0.010 0.024 0.059

G 0.010 0.022 0.058



March 2014 Page 41

Appendix 13.3: Stage F - timing of wind farm surveys and the densities of lesser black-backed gulls recorded during the breeding season

Offshore wind farm Area surveyed Project phase Year Density (birds/km

2)

Mean Peak


Boat-based survey area: Wind farm + buffer (272 km

2)

Pre-construction

2012 0.48 1.36

Boat-based survey area: Wind farm + buffer (512 km

2)

2005 3.52 3.97

2004 1.38 4.10

Walney Extension Aerial survey area: Wind farm + 4km buffer (463 km

2)

Pre-construction 2011 0.061 0.086


Walney I & II Boat-based survey area: Wind farm + buffer (367 km

2)

Post-construction 2012 0.95 1.88

Pre-construction 2008-09 0.68 1.45

During construction 2010-11 0.34 0.84

Barrow

Wind farm + 2km buffer (52 km2)



During construction 2005 2.50 6.13





Reference area (52 km2)


During construction 2005 1.34 3.04





Walney Extension Offshore Wind Farm - Planning … · Stage E: CRM for Barrow OWF and apportionment...

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