Review of Cabling Techniques and Environmental Effects Applicable
Review of Cabling Techniques and Environmental Effects Applicable
Review of Cabling Techniques and Environmental Effects Applicable
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The potential release <strong>of</strong> contaminants, previously retained in the sediment;<br />
Disturbance to important fisheries habitats such as spawning grounds,<br />
nursery grounds, feeding grounds, over-wintering areas for crustaceans,<br />
migration routes <strong>and</strong> shellfish beds;<br />
Disturbance to sensitive habitats, such as saltmarshes, biogenic reefs <strong>and</strong> eel<br />
grass beds;<br />
Noise <strong>and</strong> vibration impacts to fish <strong>and</strong> marine mammals;<br />
Electromagnetic field generation impacts to benthic species, fish <strong>and</strong> marine<br />
mammals;<br />
Risk <strong>of</strong> collision <strong>of</strong> marine mammals with cable installation vessels / support<br />
vessels; marine mammals may be disturbed by the presence <strong>of</strong> vessels <strong>and</strong><br />
cable burial equipment; <strong>and</strong>, cable entanglement with marine mammals;<br />
Marine <strong>and</strong> coastal bird species, particularly at sites <strong>of</strong> importance to nature<br />
conservation, may be disturbed by the presence <strong>of</strong> vessels <strong>and</strong> human<br />
activities;<br />
Navigational risks such as collision with cable installation vessels;<br />
Direct loss or disturbance to artefacts <strong>of</strong> importance to marine <strong>and</strong> coastal<br />
archaeology <strong>and</strong> cultural heritage; <strong>and</strong><br />
Seascape <strong>and</strong> visual impacts related to the cable installation activities <strong>and</strong><br />
the presence <strong>of</strong> cable installation vessels; <strong>and</strong> possible sea surface aesthetic<br />
effects arising from sediment plumes, particularly in areas <strong>of</strong> chalk bedrock.<br />
This study concludes that, although cabling can cover large areas <strong>of</strong> seabed, the<br />
associated environmental impacts are highly transitory, localised in extent <strong>and</strong><br />
temporary in duration. Although the corridor for cable installation impacts can<br />
be long, the footprint <strong>of</strong> impact is narrow, generally restricted to 2-3m width. For<br />
the majority <strong>of</strong> installation scenarios, the seabed <strong>and</strong> associated fauna <strong>and</strong> flora<br />
would be expected to return to a state similar to the pre-disturbance conditions.<br />
Exceptions could occur in hard clays <strong>and</strong> rock seabed types, where the cable<br />
trench would not naturally backfill, requiring intervention to backfill as part <strong>of</strong><br />
construction works or else leaving permanent scarring <strong>of</strong> the seabed.<br />
The environmental impacts associated with the installation, operation <strong>and</strong><br />
maintenance <strong>of</strong> cables associated with <strong>of</strong>fshore wind farms must be considered<br />
in the context <strong>of</strong> other influencing factors. Natural perturbations such as storm<br />
activity can have a significant effect on the structure <strong>and</strong> functioning <strong>of</strong> the<br />
seabed, as can other activities such as oil <strong>and</strong> gas exploration <strong>and</strong> infrastructure,<br />
telecommunication cable installations, certain fishing activities, aggregate<br />
extraction, <strong>and</strong> other sources <strong>of</strong> change to the physical environment. In many<br />
cases, such influencing factors may lead to related environmental impacts <strong>of</strong><br />
greater extent, duration <strong>and</strong> significance than those observed or suspected to<br />
arise as a result <strong>of</strong> the installation <strong>of</strong> <strong>of</strong>fshore wind farm cable infrastructure.<br />
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