108. These impacts would mostly be temporary, small scale and localised for the proposed East Anglia THREE project. Given the distances to other activities in the region (e.g. other offshore windfarms, aggregate extraction) and the localised nature of the impacts there is no pathway for interaction between impacts cumulatively. Whilst it is recognised that across the East Anglia Zone or southern North Sea there would be additive impacts, the overall combined magnitude of these would be negligible relative to the scale of the wider area.


109. Therefore, given that the impacts assessed for proposed the East Anglia THREE project (i.e. project level impacts) are considered negligible, or would be avoided by design, it is considered that at a cumulative (i.e. additive) level, impacts upon the water and sediment quality would be negligible.


110. There is potential for the installation of the offshore export cables to act cumulatively with dredging activities within dredging licence area 430 to reduce water quality. The dredging site is located approximately 930m from the offshore cable corridor and therefore in the event that dredging activities were being conducted in the southern extent of area 430 simultaneously with the export cable installation in the northern most extent of the offshore cable corridor elevated levels of sediment may occur. The installation of the offshore export cable was predicted to be of negligible magnitude and the likelihood of the scenario described occurring is low, therefore the cumulative impact would be negligible.


8.8 Transboundary Impacts


111. The eastern boundary of the East Anglia THREE site lies in close proximity to the Netherlands international marine boundary. As per the cumulative impacts listed above, it is considered that the temporary, small scale and localised nature of the impacts means that there is no pathway for transboundary impacts to occur (i.e. any impacts would remain largely with the East Anglia THREE site). For the offshore cable corridor the impacts would be temporary, small scale and localised and as this is fully within UK waters there is no pathway for transboundary impact. As a result, no potential transboundary impacts have been identified.


8.9 Inter-relationships


112. In order to address the environmental impacts of the proposed development as a whole, this section establishes the inter-relationships between marine water and sediment quality and other physical, environmental and human receptors.


113. There is the potential for an inter-related impact between marine physical processes and marine water and sediment quality during all phases of development. For example, changes to hydrodynamics may cause the re-suspension of contaminants


Preliminary Environmental Information May 2014


East Anglia THREE Offshore Windfarm


Chapter 8 Marine Water and Sediment Quality Page 33


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