2008, Harrison Geotechnical Engineering, Sheringham Shoal Offshore Wind Farm, Site Investigation

Description

The work covered by this report was undertaken on behalf of SCIRA Offshore Energy Limited in
accordance with Tender No. 1117 and associated Contract No. 1117, the letter of intent relating to
which was dated 9 January 2008. The work was detailed in Harrison Geotechnical Engineering
quotation reference GN12582/AS, dated 30 November 2007, subject to alterations and additions
detailed in subsequent correspondence. The project includes a desk study, direct investigation and
testing. The purpose of this report was to provide a summary of the background information, soil
data and laboratory results relevant to the site area, which constitutes the initial section of cable.
This report includes reference to a previous invasive investigation undertaken by Harrison Group
Environmental at the site in April 2006 (ref. GN10814).
The project to which this investigation relates involves the construction of an offshore windfarm, with
cables from the facility coming ashore at the site location, just to the west of the village of
Weybourne. The town of Sheringham lies around 4km to the east. The cable route proceeds in a
generally southerly direction, terminating at the Salle substation to the north-west of Reepham,
approximately 21km from the coastline. Information was required on the ground conditions along
the route of this cable in addition to data on thermal resistivity of the soils in question. It is intended
that the majority of the cable will be laid in a trench at a depth of around 1.5m, the removed material
used as backfill if possible. Directional drilling or similar methods will be used for some sections,
such as at obstructions (roads, watercourses etc.), and also for the coastline section beneath the
gravel/shingle bank. The cables are to be pulled ashore at this location, rising to a manhole from
which a trench will extend southwards.
This report provides information on the landfall section between the coastline and the intersection of
the proposed route with the A149 (The Street) at National Grid Reference 610650 342900, as
depicted on drawing GN12582/006/ACS. For the purposes of this report the term ‘site’ refers to the
proposed route of the new cable together with the immediate surrounding area.