Monitoring red-throated

diver distribution in

Liverpool Bay

Allen Risby

DONG Energy

• Burbo Bank Extension Offshore Wind Farm

• Requirement for red throated diver monitoring

• Power analysis & objectives

• Survey method

• Modelling & reporting

• Conclusions

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Agenda

Burbo Bank Extension Offshore Wind Farm

The site was awarded in May 2010 by The

Crown Estate

• Total Area: 40 km²

• Capacity: max 259 MW

• DCO September 2014

• Proposed 32 turbines with 8 MW capacity

• Construction due to commence 2016, with

commissioning Q1 2017.

Other offshore wind farm projects in or near

Liverpool Bay (with operational year)

• North Hoyle (2003)

• Barrow (2006)

• Burbo Bank (2007)

• Rhyl Flats (2009)

• Walney I+II (2011 / 2012)

• Ormonde (2012)

• West of Duddon Sands (2014)

• Gwynt y Mor (under construction)

• Walney Extension (planned)

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Liverpool Bay Special Protection Area

• Burbo Bank Extension lies mostly within

Liverpool Bay SPA;

• Liverpool Bay SPA designated in 2010, for

red-throated diver Gavia stellata and

common scoter Melanitta nigra; and

• North Hoyle, Rhyl Flats, Burbo Bank and

Gwynt-y-Môr also contained within Liverpool

Bay SPA.

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Burbo Bank Extension OWF - Examination

• Planning Inspectorate (PINS) Examination

September 2013 – March 2014

• Nationally significant infrastructure project

• Key ornithological issue is extent of

displacement of red-throated diver,

consequences of displacement and

implications for Liverpool Bay SPA

• Cumulative assessment with Burbo Bank,

Gwynt-y-Môr and Rhyl Flats wind farms

• Outline ornithological survey document agreed

during Examination with Natural England &

Natural Resources Wales

• PINS recommendation and DECC AA

• DCO granted, deemed Marine Licence with

monitoring condition

Agreed approach to RTD Monitoring

Two objectives:

1) Measure displacement effect of Burbo Bank Extension on RTD

• Digital video aerial surveys focussed on the Burbo Bank Extension site and a 4

km buffer at a suitable resolution to assess the displacement effect

2) Measure change in RTD density across the SPA following Burbo Bank

Extension construction

• Digital video aerial surveys covering Liverpool Bay SPA (full extent but not 100%

coverage) at a suitable resolution to assess the change in density across the

SPA

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Scope for RTD Monitoring

• A series of high resolution digital video aerial surveys to compare pre-construction

and post-construction distribution of RTD, the post-construction monitoring to extend

to up to 3 years (which may be non-sequential upon agreement)

• Survey designed to allow comparison with existing Liverpool Bay SPA surveys (such

as Bradbury et al, 2011) and be of sufficient "power" to provide statistical confidence

in the results

• HiDef approach based on the survey intensity and frequency identified in the digital

video aerial surveys carried out in 2011 for JNCC

• Survey methodology for Burbo Extension agreed with MMO, NE and NRW

• Surveys are taking place between November and March, as this is the key time of

year for RTD in Liverpool Bay

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Power analysis

• HiDef undertook a suite of digital aerial surveys in winter 2011 for JNCC to calculate

power to detect change in SPA

• This programme provides good basis for understanding how much survey is required to

detect change at Burbo Bank Extension

• This demonstrates that 2 surveys per winter with 17.5% coverage of the SPA will detect

33% decrease and 50% increase with sufficient power

Scenario Coverage of

site Number of

surveys

Decline to be

detected

Increase to be

detected

Power to detect

change

1 5.83% 2 33% 50% 58.4%

2 17.5% 2 33% 50% 81.0%

3 5.83% 2 50% 100% 96.4%

4 17.5% 2 50% 100% 99.8%

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Objective 1

• To measure the displacement effect from

Burbo Bank and Burbo Bank Extension and

measure the displacement distance in 500 m

bands from boundary

• Eight transects at 2.75 km apart – this is

approximately 20.2% coverage

• Area surveyed five times per winter (monthly

in Nov, Dec, Jan, Feb & Mar)

• One survey season during pre-construction

(now completed) and up to three during post-

construction (2017/18 onwards)

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Objective 2

• To determine displacement effects of Burbo

Bank Extension and other wind farms on

RTD populations in Liverpool Bay SPA

• 44 transects at 2.75km apart – this is

approximately 18.6% coverage

• Area surveyed twice per winter (monthly in

Jan & Feb)

• One survey season pre-construction (now

completed) and up to three years post-

construction

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The survey method

• HiDef bespoke system designed for bird

and marine mammal surveys

• Uses a rig with four ultra high resolution

video cameras (~ 500MPx)

• Cameras always angled away from sun

glare to stop data loss

• Surveys flown at 550m (1800ft) to avoid

flushing RTD and common scoter

• Uses a resolution of 2cm GSD

• Total strip width of 500m along continuous

transects – avoids pseudo-replication of

plot based approach

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Red-throated diver images from Liverpool Bay

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Flock of 6 red-throated divers Red-throated diver flying south-west

Red-throated diver with fish

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January 2015 SPA-wide survey summary of observations (circa 20% coverage)

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Data modelling

• Analysis based on constructing density surface models (DSM) for RTD

• Strip transects broken into 100s of ‘segments’

• Calculates abundance with upper and lower confidence intervals (CI) and coefficient of

variance (CV) in fine matrix of grid cells

• Modern modelling approach uses ‘Complex Regional Spatial Smoother’ (CReSS)

• CReSS well-adapted for birds with patchy distribution, such as seabirds

• This modelling approach has been used at one other UK offshore wind farm, as well as

for a recent series of bird and marine mammal surveys for Marine Scotland

Pre-construction survey report

• The DSM will use bathymetry as a co-

variate for diver distribution

• Combines recent digital and historical

visual aerial survey data going back to

2001

• Report on the ability of model to detect

changes in RTD abundance around

Burbo Bank and Burbo Bank Extension,

as well as within the SPA

• Report on the ability to detect

displacement in 500m or 1km bands from

Burbo Bank Extension

• This is an example output from another

wind farm site where this technique has

been recently used

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Conclusions

• Post consent monitoring that moves

monitoring away from old FEPA-style

Before and After Control Impact (BACI)

licence conditions

• Monitoring at the scale of the Liverpool

Bay SPA is more meaningful for

displacement than wind farm + buffer

monitoring alone

• Ability to incorporate previous (visual)

aerial survey data into the baseline

model

• Digital aerial surveys allow the data to

be subsequently re-analysed for other

target species.

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Thank-You.

Any Questions?

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