CEFAS24-145 RFQ for Bathymetry Surveys at Sizewell C

Tender description

Request for Quotation for Bathymetry Surveys at Sizewell C Background: The BEEMS (British Energy Estuarine and Marine Studies) programme is funded by Sizewell C Limited. Through this programme, Cefas provide authoritative scientific information on the marine and transitional waters in the vicinity of potential new build nuclear power stations and require the Supplier to deliver the elements described below. Requirement: The purpose of this project is to provide bathymetric data for the Greater Sizewell Bay (GSB) to assess the geomorphological changes of the region, hence contributing to the ongoing monitoring of the Sizewell Coastline. Cefas require two Multibeam Echosounder (MBES) bathymetric surveys to IHO Special Order (at a minimum) within the Greater Sizewell Bay (GSB) in 2025. Exact survey locations will be agreed between Cefas and the supplier during the pre-survey kick off meetings. Survey 1 will be in April 2025 and will require nearshore transects to be undertaken to assess the geomorphological changes shown by two longshore bars. Therefore, care should be taken to maximise landward extent, and the survey should be undertaken during a Spring tide window to extend the coverage in the landward sense as far as practicable. Three further East to West Corridors (‘Radar Calibration Corridors’) are included in the scope for Multibeam survey (Figure 1). For areas of survey overlap between nearshore or calibration corridors, the expectation is that coverage shall only be acquired once, and hence supplier’s should provide details of a proposed survey plan to meet this requirement and ensure that there are no gaps in coverage. Survey 2 would be undertaken in July 2025. The final area to be surveyed will be confirmed by Cefas in spring 2025, but will broadly cover the area between the two lines in Figure 2. The expected maximum survey extent would be 2 km2 but this may be reduced once areas of interest are identified, so therefore expected that this survey to be costed per day. This survey is likely to be required on spring tides to enable any shallow water areas to be accessed. Survey Strategy: Cefas aim to confirm the finalised survey areas in a kick-off meeting with the supplier prior to each of the surveys. The supplier should note that the survey due to occur in April 2025 will be required on Spring Tides. The supplier should provide a line plan two weeks prior to the survey for Cefas to review and provide comment. The regular system of sounding lines shall be supplemented by a series of crosslines for verifying and evaluating the accuracy and reliability of surveyed depths and plotted locations in April. In July, a survey plan and/or dynamic line plans will be required but can be provided nearer the time of survey. The spacing between crosslines should typically be no more than 15 times that of the main sounding lines. The supplier will be required to attend a Marine Induction meeting with the Sizewell Harbour Master prior to the survey and will be expected to adhere to the conditions set by the Harbour Master for approval for works. This includes any requirement to attend Simultaneous Operations (SIMOPS) calls, submission of Daily Reports and adherence to exclusion zones within the area. Cefas require the vessel(s), vessel crew, hydrographic survey team, and suitable equipment to undertake the surveys described. Cefas also require a lead hydrographic surveyor, with at least 5 years industry experience, to be present on the vessel(s) for the duration of each of the above surveys. Suppliers should also be aware that a client representative may join for part, or all, of the surveys. This will be confirmed within the pre-survey meeting. Cefas requires the supplier’s survey team to manage the planning (including access), notifications (including liaison with the Marine Coordination Centre (MCC) and Notice to Mariners), and safe execution of the surveys. Should licences or consents be required (e.g. a Marine Licence) these will be obtained by Cefas and provided to the supplier’s survey team prior to the survey. Coordinate Reference System (CRS): The CRS for this project shall be British National Grid (BNG) with depths reduced to Ordnance Datum Newlyn (ODN) with transformations of acquired data from geodetic coordinates referenced to the ETRF89 ellipsoid derived using the OSTN15/OGM15 transformation model. Vessel specification – Nearshore bathymetry work: Cefas require that the vessel be as a minimum MCA (MISW "small workboat” class) Category or 4, 5 and of minimum 6m length. The vessel should have a weatherproof cabin and 220-240 v AC UK mains as standard, for operation of the chosen MBES system. Daytime operations from a local port for this vessel are expected. Positioning equipment: Horizontal control (with a minimum accuracy of 0.25m or less) should be achieved by using a Real Time Kinetic (RTK) Global Navigation Satellite System (GNSS) (either dual antenna or incorporating a gyro compass to provide heading solutions) with real time corrections supplied via continuous connection to a RTK correction service. The survey spread shall also include a fully integrated Inertial Measurement Unit (IMU). Preference will be given to more modern systems. A full navigation check must be undertaken against a known point during mobilisation, and the results shared with Cefas before survey operations commence. Depth sounding equipment: For all surveys vertical control (bathymetric data) shall be acquired using an appropriate MBES system. All depths should be reduced to ODN. Whilst Cefas is open to suggestion as to the system to be used, preference will be given to multifrequency / multispectral acquisition platforms. Furthermore, Cefas is also willing to consider use of interferometric systems such as the Edgetech 6205. MBES Backscatter data is to be acquired for all survey extents. Sound Velocity Profiles (SVPs): Cefas expect SVP data to be acquired ‘as required’ during survey operations (i.e. with a new SVP collected at the start of day’s days operations and on each occasion that the Sound Velocity (SV) measured at the transducer head deviates by more than 2m/s from the near surface SV obtained from the most recent SVP). As such, we expect multiple SVP to be collected during MBES/SSS operations. Cefas anticipate SVP deployments will be made during spring tides to capture variations in the SV profile over the water column at peak ebb and peak flood as a minimum. Calibration: Cefas would expect to be provided with vessel offsets (detailing distances to phase centres, acoustic centres and rotational centres) and patch test results for the multibeam system together with other calibration checks that occurred as part of survey mobilisation within the deliverables (noting that such data can be presented within survey report). This would include checks over a feature or area of stable ground day to day and survey- survey (this does not have to be on site but can be completed en-route to survey site). Online / survey acquisition and processing software: Cefas do not require any specific navigation / MBES acquisition packages to be used, however expect those proposed to be from industry standard developers (e.g. Qinsy, Hypack, SIS or Beamworx). The survey navigation package shall provide the means of continuously monitoring the performance of the survey spread and the instruments within it as well as the quality of data being captured throughout each day of survey operations. Any variations in configuration or performance of the survey spread as well as factors impacting on the quality of data acquired shall be recorded in the surveyor’s online logs which will form part of the deliverables for the survey. Survey reporting shall provide details of the processing workflow applied to the data including any compensation/adjustments made to the data which may be applied either online or offline as part of the post processing of acquired data. The supplier shall provide details of their proposed survey system together with the hit count and other appropriate quality metrics (Total Vertical Uncertainty, Total Horizontal Uncertainty) indicating the accuracies they expect to achieve in the nearshore and offshore survey areas, noting that IHO Special Order is the minimum requirement for this project, and shall anticipate inclusion of such quality metrics in the survey deliverables with a discussion of the survey accuracy achieved provided as part of survey reporting. Data standard: The data must comply with the International Hydrographic Organization (IHO) s-44 Special Order, edition 6.1.0 (IHO, 2022) as outlined in Table 2. This standard specifies total horizontal uncertainty (THU) horizontal accuracy of 2 m and total vertical uncertainty (TVU) of 0.25m plus 0.0075% of water depth. A proposed line plan should be supplied that will meet the requirement of 100% in sonification of the survey area. With an overlap of at least 15% between adjacent swathes. A suitable number of cross lines are required. Data is to be reduced vertically to ODN using or Chart Datum (CD) by utilising the Vertical Offshore Reference Frame (VORF) model and shall either be a RTK or post-processed methodology. Processed raster, vector and charting products are to be produced using the Ordnance Survey OSTN15 / OSGM15 transformation models. Where possible, this information shall be embedded into any digital file formats or provided with a suitable ESRI ArcMap projection (.prj) file. Weather and equipment downtime: The supplier should include an indication of the vessel(s) weather limits and provide for a reasonable “Day rate for weather downtime or client standby for vessel and crew” and separate “Day rate for weather downtime or client standby for vessel only (if applicable)”. It is expected these bathymetric survey’s will be completed over a Spring-tide window, and it is the responsibility of the supplier to schedule the survey to meet forecast and predicted weather and tidal conditions, confirming these with Cefas. Costs supplied should include any charges payable by Cefas in the event of poor weather affecting operations or in the event that client standby is required. The expectation is that the survey campaigns will vary in duration. Preference will be given to responses which emphasise flexibility in mobilisation to achieve the highest data quality; for example, adapting each survey where required (e.g. into two phases due to weather) to ensure the highest possible data quality. Any permission to accrue weather downtime costs given must be in writing or by email from Cefas to the supplier. Any charges for weather downtime where no evidence of prior approval exists will not be approved and will not be reimbursed. Communications: Daily progress reports, alongside representative screenshots of raw/ unprocessed data, are to be sent to the Cefas representative via email at the end of each survey day from commencement of the survey work. These progress reports should detail any weather or equipment related down-time, plus any incidents or near misses. Quality control: The supplier’s survey team will be expected to inspect the bathymetric data in the field or immediately after (at the end of each working day) to ensure that high quality data is acquired. It is expected that where weather conditions or equipment malfunction result in compromised data the affected lines will be “re-run”. Cefas have the right to request re-runs after review of the data presented along with the DPRs. The supplier shall ensure integrity of data at all times, on a system that is secure and regularly backed up. Acquired imagery and metadata are to be delivered to Cefas (Lowestoft) on completion of the survey work via encrypted hard drive or a shared server space which will be made available for data delivery by Cefas. Health and Safety: A Risk Assessment and Method Statement (RAMS) document will be required, which will require sign off from Cefas and Sizewell C Limited prior to the survey. Typical review periods are around two weeks; therefore RAMS should be made available at least two weeks before the planned survey date. Cefas will provide a template for the supplier to complete if required. It is expected that the S=supplier complies with the review and administrative processes imposed by Cefas and Sizewell C Limited. Please note there may be several rounds of review and update required prior to sign off. A completed Vessel Safety Assessment and Inspection Document (VSAID) and vessel inspection will be required prior to survey commencement; a copy of which is included in the Bidder Pack for information, please note this can take up to one month to complete. This may not be required if the vessel has an in date CMID inspection. Cefas requires that the vessel and the crew is able to undertake the contracted activity in the stated waters in line with the requirements of the Maritime and Coastguard Agency (MCA). This relates to having suitable vessel registration and licencing plus vessel owners’ standards for complying with regulations on crew competency (including survival at sea) and their meeting of medical standards plus current training to support first aid in the event of an accident. Suitable lifesaving equipment is to be on board, suitably maintained and worn in line with maritime best practice Please see RFQ Part 1 Technical document included in the Bidder Pack for full list of deliverables