Environmental statement - Flyndre and Cawdor - Maersk Oil

Flyndre and Cawdor Environmental Statement
Section 6 Hydrocarbon Releases
Hydrocarbon
source
Drilling rig
Flyndre well
Cawdor well
Wind direction
Time take to cross
median
Evidence of
beaching
Offshore 30 knot westerly wind 15 hours No
Onshore 30 knot easterly wind 6.5 days No
Offshore 30 knot westerly wind 18 hours No
Onshore 30 knot easterly wind 1.5 days No
Offshore 30 knot westerly wind 13 days No
Onshore 30 knot easterly wind 11.5 days No
Note: In the presence of onshore winds subsea currents will cause the oil to cross the UK/Norwegian median line
Table 6‐7 Deterministic onshore and offshore modelling results summary.
6.4. ENVIRONMENTAL SENSITIVITIES
6.4.1. SEABIRDS
The effects of oil on birds has been widely studied and includes both immediate chronic impacts
which can kill birds or longer‐term, sub‐lethal, impacts that could affect individuals and populations
over many years (e.g. Camphuysen, et al. 2005, Perez, et al. 2009). To assist in determing the likely
impact on birds from a release of oil, the JNCC has produced an Oil Vulnerability Index (OVI) from
which it is possible to indicate the sensitivities of bird families that could be impacted (Section 3.5.4).
The OVI of seabirds within each offshore licence block in the vicinity of the Flyndre and Cawdor
development are shown in Table 3‐12. The JNCC monthly seabird vulnerability Index indicates an
overall low vulnerability in the area of the development; all the spring and summer months are
categorised as being of low vulnerability whic hmay be associated with a higher proportion of birds
moving inshore to breed. The OVI increases to moderate to high in some of the winter months as
particular seabird species are present in greater densities. This higher OVI index may also be due to
the annual moult in feathers when birds are more susceptible to the impacts of any surface oil.
Coastal seabirds would be vulnerable to surface oil that could coat feathers and thereby reduce
buoyancy or be ingested through preening, causing illness and other sub‐lethal effects. While
reduced survival cannot be ruled out, the fact that any oil that may reach the coastline would be of
very low concentrations, the effects are likely to be small and rehabilitation of any affected birds
would have a reasonable chance of success.
6.4.2. MARINE MAMMALS
Marine mammals that come into contact with oil may be impacted in a number of ways. The
insulation properties of fur are greatly reduced when covered in oil. The loss of insulation properties
is not considered to be a significant risk for seals and cetaceans that have relatively little fur, although
it is of significance for seal pups. Where oil does come in contact with the skin there is the potential
for it to cause irritation to the eyes or burns to mucous membranes. Ingestion of oil by marine
mammals can damage the digestive system or affect the functioning of livers and kidneys. If inhaled,
hydrocarbons can impact the respiratory system. Section 3.5.5 summarises the marine mammals
associated with the area of the development. The main species occurring in the area are cetaceans
with seals being infrequently recorded. There are no concentrations of breeding seals that appear to
be at risk from the any accidental releases. No significant risk to marine mammal populations is
anticipated such that any adverse impacts to individual cetaceans would not affect the species at a
population level.
D/4114/2011 6‐15