Nautilus Marine Survey

Tender description

Discontinuation of the procurement process for the following project: National Grid Interconnector Holdings Ltd and Elia Asset SA are currently developing proposals for a High Voltage Direct Current (HVDC) interconnector "Nautilus" between England and Belgium in support of ongoing programs for strengthening both the UK and Belgian Transmission Networks. The development process has identified the need for a HVDC Interconnector installation over a cumulative distance of approximately 200km. Survey requirements are thus arisen to establish suitability of a preferred route alignment. Lot 1: Marine geophysical survey including, but not limited to: • Survey design and planning • Multi-beam echo-sounder (MBES) survey • Side-scan sonar (SSS) survey • Sub-bottom-profiler (SBP) survey • Magnetometer (MAG) survey and in support of UXO avoidance prior to geotechnical works • General video inspection to map cable and pipeline crossing locations and inspect UXO incidents and possible benthic habitats • Geophysical Survey reporting and charting • Data delivery including GIS formats • Allocation of geotechnical location selection in collaboration with Employers • Final Integration of geophysics and geotechnics; reporting, charting and data delivery, including GIS formats Shallow marine geotechnical survey (investigation 3-10m below seabed), including but not limited to: • Marine geotechnical survey along the propose cable corridors including the intertidal, • Survey design and planning • Sediment sampling to a nominal up to 6 m below the seabed and preliminary offshore sediment description and basic testing • Proposal (in collaboration with Employers) and conducting of onshore geotechnical lab testing • PCPT survey to a nominal up to 5 m below the seabed and generation of preliminary offshore plots in general for the cable route • PCPT survey to a nominal up to 10 m below the seabed for crossing navigation routes, and generation of preliminary offshore plots • In-situ thermal conductivity measurements to a nominal up to 3 m below the seabed and generation of preliminary offshore plots • Geotechnical survey reporting and charting • Data delivery including GIS formats, • Input into the integration of results with the geophysics