7.6.2.7.1 Assessment of effect magnitude and/or impact significance 377. Taking the aforementioned considerations into account, the worst case changes to the sea bed morphology and sediment transport due to cable protection measures for offshore cables are likely to have the following magnitudes of effect (Table 7.34):


Table 7.34Magnitude of effect on sea bed morphology and sediment transport due to cable protection measures for offshore cables under worst case scenario


Location


Inshore of cable


crossings


Offshore of cable


crossings Scale Low


(up to 2.5% cable burial)


Low


(up to 10% cable burial)


High High Negligible Low High High Negligible Low Duration Frequency


Reversibility Magnitude of Effect


378. At the location of the potential cable crossings with the Galloper Offshore Wind Farm and Greater Gabbard Offshore Wind Farms, and for around 20km further east, these effects could potentially affect parts of the ‘Suffolk Natura 2000’ site (specifically parts of the Outer Thames Estuary SPA located within).


379. Similarly, these effects inshore of the cable crossings could also directly affect parts of the ‘Suffolk Natura 2000’ site (specifically parts of the Outer Thames Estuary SPA located within) and indirectly affect parts of the ‘East Anglia’ coast.


380. Given these aspects, the sensitivity and value of the ‘Suffolk Natura 2000’ site (specifically parts of the Outer Thames Estuary SPA located within) and ‘East Anglia’ coast are presented in Table 7.35.


Table 7.35 Sensitivity and Value assessment for the ‘Suffolk Natura 2000’ site and ‘East Anglia’ coast Receptor ‘Suffolk


Tolerance


Natura 2000’ site


‘East Anglia’ coast


Low Low Adaptability Recoverability Low Low Negligible Negligible Value High Medium Sensitivity Medium Low


381. The significance of impacts relating to sea bed morphology and sediment transport arising from the presence of cable protection measures for offshore export cables would differ depending on the location of the works and the identified receptor groups under consideration.


Preliminary Environmental Information May 2014


East Anglia THREE Offshore Windfarm Chapter 7 Marine Geology, Oceanography and Physical Processes Page 74


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