Marine Geophysical and Geotechnical Surveys

Tender description

Text to be corrected in the original notice: Place of text to be modified: II.2.7 Instead of: Duration of the contract, framework agreement or dynamic purchasing system: Duration in months: 6 This contract is subject to renewal: No Description of renewals: Not provided Read: Duration of the contract, framework agreement or dynamic purchasing system: Duration in months: 12 This contract is subject to renewal: No Description of renewals: Not provided Place of text to be modified: II.2.4 Instead of: Description of procurement: Description of procurement: Provision of marine geophysical and geotechnical sSurveys for HVDC interconnector cable route between Morocco and the UK. Survey route is approximately 3,600km. Xlinks is developing an HVDC interconnector between Morocco and the United Kingdom. This notice concerns the award of 1 contract for the marine geophysical, geotechnical and environmental route investigation surveys along the interconnector route between Morocco and the United Kingdom. The survey shall be carried out in a designated corridor centred on the cable route. The corridor is expected to vary with water depth but will be no less than 700m wide and the centre line distance of the cable route is expected to be approximately 3,600 km. Though these figures are subject to variation. The route survey must provide a detailed mapping of the bathymetry, of the seabed surface including morphological and geological features and man-made-objects and of the sub-surface geology. The scope of the assignment will include the following: 1) Nearshore and offshore geophysical and hydrographic survey; This survey is to be undertaken along the entire route. The shore-ends will use land-based observations at low tide and shallow draft vessel to ensure data coverage extends across the entire proposed cable route from beach to beach. This will consist of a survey using all of the following geophysical sensors - side scan sonar (SSS), multi-beam echo sounder (MBES), magnetometer, sub-bottom profiling, and grab sampling to support seabed interpretation. Supplementary geophysical and topographic survey methods will be used across the inter-tidal areas and up to the beach at the landfall(s) in each country. 2) UXO survey; Magnetometer survey to detect potential UXO 3) Nearshore and offshore geotechnical investigations; The geotechnical survey will aim to provide information of the characteristics of the subsea soils through core sampling of the seabed with Vibrocorer or Piston corer (3m or 6m below seabed); CPT tests of the seabed (3m or 6m below seabed); T-bar tests; dissipation tests; box coring; deeper boreholes (~25m) at landfall locations (nearshore/onshore) to inform potential HDD requirements; measurement of seabed temperature and conductivity; geotechnical laboratory tests (including carbon dating, x-ray) and tests of thermal properties soil samples. 4) Nearshore and off