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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Physical change<br />
along the cable route <strong>and</strong> reduce to less than 20 mg/l within 1000ft <strong>of</strong> the cable<br />
route.<br />
It is interesting to note that the results <strong>of</strong> the above modelling exercise completed<br />
in the USA are broadly in agreement with the modelling <strong>and</strong> site measurements<br />
discussed above for a number <strong>of</strong> wind farms in the UK.<br />
4.5.3 CONCLUSIONS AND FURTHER RESEARCH<br />
The findings from the studies undertaken for a number <strong>of</strong> UK <strong>of</strong>fshore wind farms<br />
indicate that the disturbance to seabed sediments during cable burial operations<br />
are likely to be short term <strong>and</strong> relatively localised, particularly if ploughing<br />
techniques are employed. It is unlikely that cumulative or in-combination<br />
impacts will present significant problems because <strong>of</strong> the short term nature <strong>of</strong><br />
the burial operations.<br />
As noted earlier there is limited research <strong>and</strong> advice on the quantification <strong>of</strong><br />
material arising from cable burial operations, particularly if jetting, dredging or<br />
cutting/excavating methods are adopted. This lack <strong>of</strong> base information on the<br />
release <strong>of</strong> sediment into suspension limits the benefits that could arise from the<br />
use <strong>of</strong> more sophisticated modelling techniques to establish the fate <strong>of</strong> released<br />
sediment. It is, therefore, suggested that this is an area where further research<br />
would be <strong>of</strong> value. It is appreciated that monitoring requirements included in<br />
FEPA licences for UK Round 1 <strong>and</strong> 2 <strong>of</strong>fshore wind farms will provide valuable<br />
data for the quantification <strong>of</strong> the impacts <strong>of</strong> cable burial operations.<br />
4.6 Mitigation Measures<br />
The previous sections have discussed the influence <strong>of</strong> cable burial operations<br />
on sediment disturbance. In practice the main areas where mitigation measures<br />
can be adopted to reduce this disturbance are during the selection <strong>of</strong> the cable<br />
route <strong>and</strong> cable burial method. Both the route <strong>and</strong> burial methods adopted will<br />
be a balance between the engineering issues associated with the route corridor<br />
(see Section 3.10 on the Burial Assessment Surveys) <strong>and</strong> the key environmental<br />
issues associated with the site. The range <strong>of</strong> environmental issues likely to be<br />
encountered is discussed in Section 5.<br />
An appropriate level <strong>of</strong> site investigation (see Section 4.2.1) is an essential to<br />
ensure that the optimum route <strong>and</strong> burial methods are selected for the cable.<br />
The level <strong>of</strong> data gathered should be sufficient to provide confidence in the<br />
selected route <strong>and</strong> burial method <strong>and</strong> allow the assessment <strong>of</strong> the potential<br />
environmental impacts. It is at this stage that mitigation (e.g. re-routing) may<br />
be considered should the environmental impacts be significant. The completion<br />
<strong>of</strong> an appropriate level <strong>of</strong> site investigation in the early stages <strong>of</strong> the project<br />
will reduce the risks <strong>of</strong> delays during the consenting process <strong>and</strong> the risk <strong>of</strong><br />
major changes in the later stages <strong>of</strong> a project. It will also allow a more strategic<br />
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