172. As both the magnitude of temporary physical disturbance and the sensitivity of receptors within the offshore cable corridor are considered to be low, the significance of the impact is likely to beminor adverse (Table 10.9).
173. At the cable landfall, the worst case scenario for physical disturbance would be the installation of the ‘short’ HDD option (see Chapter 5 description of the Development for further detail). Disturbance to the intertidal habitats would occur where machinery, i.e. the tracked excavator, is required. However, given the small scale and very temporary nature of this impact the magnitude is considered to be low.
174. Much of the lower shore at the landfall site has been described as ‘littoral coarse sediment’ (A2.1) using the EUNIS codes and
LS.LCS.Sh.Bar.Sh (Barren littoral shingle) using the MNCR scheme. This habitat is very common along North Sea coastline and due to the barren nature of the existing ecology, this biotope is not considered sensitive to disturbance. This area of coastline regularly experiences physical disturbance from natural sources and therefore is considered to have a negligible sensitivity.
175. Taking into consideration the embedded mitigation of using the HDD method, the low sensitivity and low magnitude of the impact along with the low value of the receptor it is predicted that the impact to intertidal ecology would be negligible.
10.6.1.1.3Summary of impact 1 176. To conclude, the greatest magnitude of impact of physical disturbance that would be caused by the proposed East Anglia THREE project to benthic ecology is low and the greatest sensitivity is low. It is unlikely that there would be any interactions between the different study areas and therefore the overall worst case impact of physical disturbance is considered to be ofminor adverse significance. As a result, no mitigation over that which is embedded (section 10.3.3) within the project design is suggested. Furthermore due to the comprehensive survey work conducted across the study areas the confidence in this assessment is high.
10.6.1.2 Impact 2: Increased Suspended Sediment Concentrations 177. Increases in suspended sediment concentrations within the water column may occur through the installation of foundations and inter-array cables in the East Anglia THREE site, and through the installation of export cables in the offshore cable corridor.
178. Other activities such as the disturbance of the sea bed by jack up vessels or the placement of cable protection, are not likely to increase the suspended sediment concentrations levels to an extent where they would cause an impact to benthic
Preliminary Environmental Information May 2014
East Anglia THREE Offshore Windfarm
Chapter 1 Introduction Page 62
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104