LionLink Marine Survey

Description

National Grid Interconnector Holdings Limited and TenneT are developing proposals for a High Voltage Direct Current (HVDC) Multi Purpose Interconnector "Lion (Euro) Link" between England and Netherlands in support of ongoing programs for strengthening both the UK and Dutch Transmission Networks. The development process has identified the need for a HVDC Interconnector installation over accumulative 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 pUXO 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