ENVIRONMENTAL STATEMENT BARDOLINO DEVELOPMENT

Bardolino Development Environmental Statement
It is likely that the noise effects of the vessels associated with the proposed activities would
be similar in character to normal commercial shipping activities. Consequently, cumulative or
global impacts would be unlikely.
6.7.5 Consultee concerns
During the informal consultation process (Section 1.6), JNCC advised that within the ES,
Shell should consider whether any of the proposed activities are likely to cause 'deliberate
disturbance’ to a European Protected Species (EPS). JNCC advised that whilst Shell needed
to carry out the assessment, the use of mitigation measures (including the use of a Marine
Mammal Observer (MMO), the restriction of piling activities to daylight hours, and those other
measures included within the Shell agreed procedure for offshore piling activities), are likely
to be sufficient mitigation measures to ensure that the proposed activities do not cause
disturbance to any EPS.
6.7.6 Adequacy of proposed mitigation measures
Noise during the Bardolino development activities would be generated underwater primarily
by piling activities during the installation of the manifold, production tree and valve skid. The
duration of the main piling activities will be around 24 hours in total, over two periods of
activity. Modelling has shown that various species of marine mammals within 10 m to 1.5 km
of the site could experience received noise levels that might cause a strong avoidance
reaction (Table 6.11); that is, the animals would move away from the source of noise.
Evidence suggests, however, that marine mammals disturbed temporarily in this way would
readily move back into the area once the noise ceased.
The area in which marine mammals might be exposed to received noise levels that might
elicit a strong avoidance reaction is very small in comparison with the area of the central
North Sea. The densities of marine mammals in this area are low, and the proposed period
for piling does not coincide with any peaks of marine mammal abundance (Section 4.4.4). It
is therefore expected that the overall potential impact of piling operations, even without the
mitigation measures described below, would not be significant.
Modelling has also shown that the area within which received noise levels may be loud
enough to cause a TTS would extend to approximately 50 m for a Minke whale, and that
piling noise would not be expected to result in a TTS for harbour porpoise, bottlenose dolphin
or killer whale (Table 6.11). The mitigation measures that the project would employ would be
designed to ensure as far as possible that piling did not begin while marine mammals were
within this zone, that marine mammals were gradually exposed to increasing levels of noise
so that they could move away from the source of noise, and finally that piling would be halted
if marine mammals were observed within a pre-defined zone around the site.
The JNCC has developed guidelines for use during seismic survey operations, and these can
be modified and applied to piling operations in order to reduce the likelihood that marine
mammals would be exposed to significantly elevated noise levels. Shell has developed a set
of guidelines in line with the JNCC guidelines, to be used for all offshore piling operations
within the UKCS (Shell, July 2007). These procedures are included in Appendix 4. These
Guidelines for Minimising Acoustic Disturbance to Marine Mammals from Piling Operations
have been discussed and agreed with JNCC, and will be followed during the piling operations
at Bardolino. Important mitigation features from these guidelines, that would be incorporated
into the Bardolino piling operations, are:
• Piling would only begin during daylight hours.
• A qualified and experienced marine mammal observer (MMO), whose suitability has
been agreed with the JNCC prior to the operation, would be present on the standby
vessel throughout the operations, to monitor the presence of marine mammals in the
area.
April 2008 Page 6-31