Presence of man-made assets
Presence of man-made assets
Man-made assets include all artificial structures and objects which are present during different phases of infrastucture lifecycle, such as wind turbines, subsea cables, platforms, and different types of vessels. Mere presence of these assets can interfere with various biodiversity receptors in marine ecosystems.
Lifecycle phase
Impact
Biodiversity receptor
Measure for wind turbine
Measure for grid
Avoidance or minimisation
Status offshore
Planning
Avoidance, displacement and injury
All
During geophysical surveys necessary for site characterisation, consider using least-intrusive equipment and doing surveys outside of sensitive periods for threatened species available at the site.
Avoidance / minimisation
Implemented
Planning
Collision
Bats
Siting: Avoid migration flyways or areas used frequently by bats when siting.
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Avoidance/minimisation
Concept
Planning
Collision, avoidance and displacement
Birds
Design: Combine blade height with the increase of the
lowest tip height
—
Minimisation
Concept
Planning
Collision
Birds
Vision-based collision mitigation: Applying achromatic patterns to the blades to enhance the detectability of turbines, painting blades in black, using UV colors.
—
Minimisation
Tested
Planning
Collision
Birds
Micro-siting/Layout design: Arranging turbines in clusters because common eider birds are more likely to avoid a group of turbines than a single row of turbines - alignment should take into account flight paths of migrating birds and their migratory routes.
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Minimisation
Concept
Planning
Collision
Birds
Careful siting based on sensitivity mapping: avoiding valuable areas for sensitive seabird species (e.g. near to seabird breeding colonies), avoding migration flyways for vulnerable species and routes that seabirds use to commute between their colonies and foraging areas.
—
Avoidance
Implemented
Planning
Collision
Birds
Use standardised bird surveys when siting
Avoidance
Implemented
Planning
Avoidance, displacement and injury
Fish
Siting: Avoid spawning and nursery habitats and species-rich habitats. If information on where these are located is not available, do a dedicated survey within EIA.
Avoidance
Implemented
Planning
Avoidance, displacement and injury
Marine mammals
—
Siting: Avoid haul out sites in general, but especially during sensitive periods such as breeding season.
Avoidance
Implemented
Construction
Avoidance, displacement and injury
All
Prepare detailed and comprehensive construction protocols that include all vessel movements and activities. The aim should be to reduce the number of trips to only necessary ones. Helicopters should fly at the altitude which avoids collisions with birds.
Minimisation
Implemented
Construction
Avoidance, displacement and injury
Birds
Having contact with a bird watcher on land who can monitor bird traffic so collision or disturbance of animals can be avoided or minimised
Minimisation
Implemented
Construction
Avoidance, displacement and injury
Birds
Employing bird watcher on installation vessels to observe, react and avoid potential collision
Minimisation
Implemented
Construction
Avoidance, displacement and injury
Birds
Timing: Avoid doing construction in areas important for birds during specific times (e.g. migratory period, over-wintering period, breeding periods).
Avoidance
Implemented
Construction
Avoidance, displacement and injury
Fish, marine mammals and sea turtles
Vessel regulations and restrictions: Construction vessels should adjust their speed and routes to reduce the noise emissions and minimise the chances of animal disturbances.
Minimisation
Implemented
Construction
Avoidance, displacement and injury
Fish, marine mammals and sea turtles
—
Speed: Cable burial vessel should not travel at over 10 knots during installation operations to reduce the risk of fatal injury.
Minimisation
Implemented
Construction
Avoidance, displacement and injury
Fish, marine mammals and sea turtles
Employ Marine Mammal Observer (MMO) on the installation vessel to ensure no animal is being distrubed or injured.
Avoidance
Implemented
Construction
Habitat disturbance
Benthos
In soft sediment areas, place scour protection around the foundations in order to avoid the sediment resuspension which can affect benthic communities (and subsequently plankton).
Minimisation
Implemented
Operation
Collision
Birds and bats
Shutdown/curtailment during already determined periods according to time of day/night (e.g. 1 hour after sunset), ambient environmental factors (e.g. westerly wind and low temperatures).
—
Minimisation
Concept
Operation
Collision
Birds
Shutdown on demand/curtailment using either camera (e.g. DTBird, IdentiFlight) and/or radar technology (e.g. Robin Radar Max, STRIX Birdrack) to do post-construction monitoring and identify which turbines should have rotation halted at what times (e.g. migratory periods or other periods of high activity).
—
Minimisation
Tested
Operation
Collision
Birds
Observer-led shutdown on demand/curtailment during which bird surveyors observe field and identify prority bird species and their risk for collision.
—
Minimisation
Concept
Operation
Collision
Birds
Shutdown/curtailment (reduction of speed of the turbine blades to a maximum of two revolutions per minute) during migration.
—
Minimisation
Tested
Operation
Collision
Birds
Preventing bird collisions through active control of wind turbines: making small adjustments to the rotor speed of wind turbines after detecting the presence of birds within a certain distance of the blades.
—
Minimisation
Concept
Operation
Attraction
Bats and birds
Using deterrent devices to prevent birds and bats from approaching offshore wind farms, such as ADD and visual deterrents.
Minimisation
Implemented
End of life
Avoidance, displacement and injury
All
Prepare detailed and comprehensive decommissioning protocols that include all vessel and helicopter movements and activities. The aim should be to reduce the number of trips to only necessary ones. Helicopters should fly at the altitude which avoids collisions with birds.
Minimisation
Implemented
End of life
Avoidance, displacement and injury
Birds
Having contact with a bird watcher on land who can monitor bird traffic so collision or disturbance of animals can be avoided or minimised.
Minimisation
Implemented
End of life
Avoidance, displacement and injury
Birds
Employing bird watcher on decommissioning vessels to observe, react and avoid potential collision.
Minimisation
Implemented
End of life
Avoidance, displacement and injury
Fish, marine mammals and sea turtles
—
Speed: Cable removal vessel should not travel at over 10 knots during installation operations to reduce the risk of fatal injury.
Minimisation
Implemented
End of life
Avoidance, displacement and injury
Fish, marine mammals and sea turtles
Employ Marine Mammal Observer (MMO) on the decommissioning vessel to ensure no animal is being distrubed or injured.
Avoidance
Implemented
