This content requires Adobe Flash Player version
or later.
Either you do not have Adobe Flash Player installed,
or your version is too old,
or there is a problem with your Flash installation and we were unable to detect it.
Installation using open trenching method – Option 2 Open trenching - assessment assumptions
This option assumes that during the construction of East Anglia ONE the following are undertaken:
Installation of up to four cables along approximately 37km of the onshore cable route (mostly via open trenching) with haul road along the entire length except where cables are installed beneath obstacles using HDD;
5.2
Creation of two jointing pits at up to 40 locations along the cable route; HDD for up to four cables at 10 points along the route; and
Removal of the haul road and reinstatement of land and features along approximately 37km of the onshore cable route.
Creation and use of two primary and seven secondary Construction Consolidation Sites
Therefore for each new project of East Anglia THREE and East Anglia FOUR the above works would be required to be repeated. A working width of approximately 23m is assumed (which is a worst case based on the width assessed for East Anglia ONE but excluding the space required for the ducts for East Anglia THREE and East Anglia FOUR (see Diagram 4-6 in Chapter 4 - Description of Development of the Environmental Statement and included as Appendix C).
6 6.1 Potential impacts associated with each option
The residual impacts presented in detail in the Environmental Statement for East Anglia ONE serve as a basis to compare the two options and their associated impacts. Note that the order of topics (and impacts within each topic) aligns with the Environmental Statement and is not based upon any order of impact.
Table 1.2. Potential Impacts on Ground Conditions and Contamination Option 1: Pre-Installed Ducts
Excavation of material for cable trench
Local changes to geomorphology at open cut watercourse crossings.
Impact to soils from fuel, lubricants, chemicals, waste materials, dust, sediment in surface water and cement slurry
Remobilisation of existing contamination due to construction
Smaller footprint with isolated disruption.
Smaller footprint with isolated disruption.
This would be covered by EMP, therefore no impact/impact mitigated and within compliance limits
Option 2: Open Trenching
Far greater footprint and continuous linear disruption.
Far greater footprint and continuous linear disruption.
This would be covered by Ecological Management Plan (EMP) therefore no
impact/impact mitigated and within compliance limits