4.4.5.2 Option to Route up the Estuaries 39.
Early meetings with the local authorities raised the possibility of routeing the cable up the Deben, the Orwell or the Stour Estuaries in an attempt to reduce disruption onshore. Harwich Haven Authority expressed concerns regarding routeing up the Stour and the Orwell due to the potential for further harbour works in Felixstowe and Harwich and the need for future deepening in these port approaches.
40. A high level assessment of the installation challenges associated with the cabling beneath the Orwell, Stour and Deben estuaries was commissioned. This report concluded that cable routeing through these estuaries was not recommended due to the environmental designations of the Deben, Orwell and Stour, conflicts with harbour requirements in the Orwell and Stour, and conflicts with leisure activities, particularly yacht moorings, in the Orwell and Deben. The width of the channels of all estuaries was also considered unsuitable for multiple parallel cable installations. The option to route up the estuaries was therefore discounted.
4.4.5.3 Onshore Area of Search 41.
Further detailed and finer scale constraints mapping work was undertaken to refine ICCA to an Onshore Area of Search. Key international and national environmental constraints sourced from the public domain were mapped as discrete layers at 1:50,000 scale. These included National Parks, Areas of Outstanding Natural Beauty (AONB), World Heritage Sites, Sites of Special Scientific Interest (SSSI), Ramsar sites, Special Areas of Conservation (SAC), Special Protection Areas (SPA), National Nature Reserves (NNR), Scheduled Monuments and Registered Parks and Gardens. Local environmental constraints were then identified including areas of mature woodland. Potential route corridors, based on environmental constraints, were identified.
42. An engineering feasibility study considered how cables could, in practice, route around, through or under existing infrastructure. This ‘buildability’ assessment complemented the constraints assessment and assisted in the route definition. The following criteria were used
Ease of installation/terrain;
Installation methods required, e.g. the need for directional drilling; Availability of working area required for construction/installation; Presence of other major services, e.g. gas pipelines and transmission circuits;
Number and difficulty of obstacle crossings, e.g. rivers, railways and pipelines and crossing methods; and
Preliminary Environmental Information May 2014
East Anglia THREE Offshore Windfarm
Chapter 4 Site Selection and Alternatives Page 9
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