Review of Cabling Techniques and Environmental Effects Applicable

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