Export Cable Route Survey

Bibby HydroMap were commissioned to undertake a detailed geophysical survey along two proposed cable export route corridors.

The site is situated in the central North Sea, approximately 30km southeast of Montrose on the southeast coast of Scotland.

The main objectives of the survey were to:

  • Acquire data that conforms to IHO S44 Standard Order 1a Surveys (to 40m), with regards to error budgets.
  • Measure seabed topography and morphology and identify the nature of the seabed sediments.
  • Undertake shallow geophysical surveys using sub-bottom profiler to identify sub-seabed geology, to provide data for the design of a subsequent programme of geotechnical sampling, in particular to derive cable burial assessment
  • Identify the location, extent and nature of any impediments to the installation of the export cables such as wrecks, sea floor debris, rock outcrops and other cables/pipelines.

These objectives were achieved by utilising multibeam echo sounder, side scan sonar, marine magnetometer and surface-towed ‘boomer’ sub-bottom profiler, run simultaneously on all survey lines. The survey was undertaken using Bibby HydroMap's own dedicated survey vessels, Freja and Chartwell, with Freja surveying the inshore sections to the 30m contour and Chartwell surveying offshore of the 3 nautical mile limit.

The export cable route corridors were planned with a total of 11 longitudinal lines at 100m line spacing, covering a corridor 1km wide.  Lines were generated at 50m line spacing from inshore of the 20m contour for multibeam coverage, where required.  The survey lines were projected 200m into the development area to ensure adequate overlap.  The Southern Route corridor overlapped into the northern corridor by 200m except for the route centreline, which was extended to the common offshore point to aid geological centreline profiling during the processing and reporting phase of the project.

Related Pages: Hydrographic and Geophysical Survey Subsea Cable Survey and Inspection