Page 174 - Alderney Regional Environmental Assessment of Renewable Energy: Environmental Report

Alderney Regional Environmental Assessment of Renewable Energy:
Environmental Report
considering the unconfined nature of the area, the turbines are not considered likely to act as a
barrier to movement. Exposure to change is therefore considered low, and the overall impact
is insignificant to minor adverse impact.
5.6.2.11Introduction of new structures
The operation of tidal stream turbines and offshore substations has the potential to introduce
new structures that could become surfaces for the settlement of designated features and may
even have the potential to act as a benefit to their receiving environment. Reference should be
made to Fish and Shellfish (Section 5.3.2.9) for further details. However, this potential benefit
needs to be studied in greater detail, allowing it to be taken into consideration when
undertaking project-level impact assessments on the benthic community. Overall, sensitivity to
change is considered low to moderate and exposure to change is low resulting in a potential
insignificant to minor beneficial impact.
5.6.2.12Seal haul-out damage
Damage to seal haul-out sites could potentially occur as a result of the construction, operation
and decommissioning of cable routeing. Reference should also be also made to Marine
Mammals (see Sections 5.5.2.2 and 5.5.2.10). There is a known seal colony to the north of
Burhou Island within the designated Ramsar site, and other seal colonies that qualify for
designation under Natura 2000 sites in the wider study area. Small numbers of grey seals haul-
out at sites on the Channel Islands including the Nannels and Renonquet rocks to the west of
Burhou Island near Alderney (Alderney Wildlife Trust, 2012; Open Hydro, 2008). Additionally
the most southern European colonies of harbour seals are located in France in the Baie du
Mont Saint Michel, Baie des Veys and Baie de Somme with a total count of 295 seals hauled
out at these sites recorded in 2008 (Hassani et al, 2010).This assessment considers that in
general, ships more than 1,500m away from grey seal haul-out areas are unlikely to evoke any
reactions from grey seals and therefore exposure to change is considered to be low. Between
900m and 1,500m, grey seals could be expected to detect the presence of vessels and at
closer than 900m a flight reaction could be expected (Scottish Executive, 2007). Overall,
sensitivities are considered to be moderate and importance of marine mammals features are
high resulting in a minor adverse impact.
5.6.2.13Electromagnetic field
The operation of cable routeing has potential to create Electromagnetic fields (EMFs) and have
associated effects on Fish and Shellfish (See 5.3.2.10) and Marine Mammals (see Section
5.5.2.9). This assessment considers that designated features may be affected by the
production of EMF such as altering migration patterns. Whilst sensitivity of mammals is
considered to be low fish species such as salmon are designated features and have been
identified as electro sensitive and potentially effected by EMF and sensitivity is therefore
considered to be moderate. Due to limited area potentially affected by EMF exposure as a
result of a single turbine is considered low resulting in a minor adverse/insignificant impact.
However, the level of exposure associated with the potential full build out of the Draft Plan is
considered to be moderate resulting in an insignificant to moderate adverse impact.
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