Environmental Statement Chapter 12 Appendix A - GEMS Geophysical Survey Report

Transcription

1 DOGGER BANK CREYKE BECK April 2013 Environmental Statement Chapter 12 Appendix A - GEMS Geophysical Survey Report F-OFC-CH-012 Appendix A Issue 1 Chapter 12 Page i 2013 Forewind

2 DOGGER BANK CREYKE BECK Title: Dogger Bank Creyke Beck Environmental Statement Chapter 12 Appendix A - GEMS Geophysical Survey Report Contract No. (if applicable) Forewind Document Number: F-ONC-CH-012 Appendix A Issue No: 1 Issue Date: 19-Oct-12 Status: Issued for 1st. Technical Review Issued for PEI3 Issued for 2nd. Technical Review Issued for Application Submission Prepared by: GEMS Survey Ltd. Approved by: GEMS Survey Ltd. Checked by: (Forewind) Sophie Barrel Signature / Approval (Forewind) Approval Date: 1-Dec-12 Gareth Lewis Revision History Date Issue No. Remarks / Reason for Issue Author Checked Approved 19-Oct-12 1 Issued for Approval GEMS F-OFC-CH-012 Appendix A Issue 1 Chapter 12 Page ii 2013 Forewind

3 GEMS International Group of Companies Geotechnical, Geophysical and Metocean Expertise around the World GEOPHYSICS RESULTS REPORT VOLUME 4 OF 9 DOGGER BANK TRANCHE A ACOUSTIC AND GEOPHYSICAL SURVEY PREPARED FOR FOREWIND LIMITED DOCUMENT REF.: REVISION: OCTOBER GEMS Survey Limited St. James House, St. James Place, Gains Lane Devizes, Wiltshire, SN10 1FB United Kingdom Registration Number: T: F: [email protected]

4 DOCUMENT CONTROL AND REVISION STATUS Document Title Geophysics Results Report Volume 4 of 9 Project Client Project No. Document Ref. Dogger Bank Tranche A Acoustic and Geophysical Survey Forewind Limited GSL10109 Revision No. 03 Document Distribution Copy Number Distributed to Date Master GEMS Server 19 October GEMS 19 October This report is copy number: Signed: Revision History Date Orig. Chk. Appr. Client 00 Draft 20 September 2011 JMO/LJE/JTI JST 01 Issue to Client for Review 23 September 2011 JMO/LJE/JTI JST PHA 02 Issue to Client After Review 17 February 2012 JMO/LJE/JTI JST PHA 03 Issue to Client After Review 19 October 2012 JMO/LJE/JTI BBR PHA Signatory Legend: JMO Joseph Morris LJE Louise Jemmett JTI Jenny Tippin JST Jon Steer JMO Joseph Morris BBR Ben Barton PHA Phil Hayles The following personnel are the designated contacts for any queries regarding this document: Name Job Title Telephone Heath Turck Project Manager [email protected] Ed Weare Project Manager [email protected] GEMS International Group of Companies i

5 TABLE OF CONTENTS 1. INTRODUCTION Project Overview Objectives Document Overview Forewind Client Feedback GEMS Response SCOPE OF WORK Site Definition Line Plans Equipment Simultaneous Operations PROJECT CONTROL Horizontal Datum Vertical Datum Time Datum Units Datum BATHYMETRY Depths SEABED FEATURES Sediment Overview Sediment Transportation Existing Infrastructure Contacts SUB-BOTTOM GEOLOGY Unit a Unit b Unit c Unit d Unit e Unit f Unit g GEOPHYSICAL AND HYDROGRAPHIC INTERPRETATION Overview Slopes Near Surface Geological Discussion Sediment Sampling and In-Situ Testing POTENTIAL HAZARDS Shallow Gas Potential Peats Faults Small Bodies of Sand GEMS International Group of Companies ii

6 8.5 Channels / Soft Channel Infill Cobbles / Boulders Surface Obstructions LIST OF FIGURES Figure 1 Dogger Bank Zone...1 Figure 2 Lines Run by Kommandor Jack Figure 3 Lines Run by Aquarius Figure 4 Grid of fictional tidal stations Figure 5 Tidal Level Contours Figure 6 Colour banded bathymetry overview of Tranche A Figure 7 Shallow sandwaves observed in the bathymetric dataset Figure 8 Bathymetric profile across symmetrical sandwaves Figure 9 Low relief flat area, with WD 20-25m observed in the East of the Tranche A site Figure 10 Depths of 30m-40m in southeast of site, highlighting the base of the valley forms Figure 11 Depths of 30-40m along northwest boundary, delineating the base of valley forms Figure 12 Adapted Folk Sediment Classification Figure 13 SSS record of stiff clay with frequent cobbles and occasional boulders Figure 14 Predominance of sand across the Tranche A site Figure 15 SSS record of sand Figure 16 SSS record of stiff clay (occasional) and gravel Figure 17 Megaripples observed in the SSS mosaic Figure 18 SSS record of mixed sediment classification Figure 19 SSS record of mixed sediment classification Figure 20 SSS record of isolated gravel patches Figure 21 SSS mosaic of gravel patches Figure 22 Megaripple variations Figure 23 SSS record of sediment migration, 03 December Figure 24 SSS record of sediment migration, 21 December 2010; Figure 25 Areas of sandwaves identified in bathymetry (encircled in black) Figure 26 Sandwave direction, wavelength and amplitude Figure 27 Sandwave direction, wavelength and amplitude Figure 28 Magnetometer detected gas pipeline Figure 29 SSS mosaic of the detected SEAL gas pipeline Figure 30 Isolated Boulder (3.1x1.5x0.7m) Figure 31 Boulder Cluster (image extent 50 x 90m) Figure 32 Trawling activity in evident in gravel sediment Figure 33 Trawl scar termination at sediment boundary Figure 34 Wreck (ID 1000) identified in the bathymetric data (top) and SSS record (bottom) Figure 35 Wreck (ID 1001) identified in the bathymetric data (top) and SSS record (bottom) Figure 36 Wreck (ID 1002) identified in the bathymetric data (top) and SSS record (bottom) GEMS International Group of Companies iii

7 Figure 37 Geological schematic of Interpreted Sub-seabed Geology in Tranche A Figure 38 Shallow sub-bottom profile showing Unit a overlying Unit b Figure 39 Shallow sub-bottom profile showing the sand waves with exposed Horizon B Figure 40 Base of Unit b (depth in metres bsb) Figure 41 Thinning of Unit c in localised area of faulting; Figure 42 Acoustically transparent and chaotic internal structure of Unit c Figure 43 Base of Unit c (depth in metres bsb) Figure 44 Spatial illustration of depth BSB (m) to Horizon E, the base of Unit e Figure 45 Spatial illustration of depth BSB (m) to Horizon F, the base of Unit f. The red polygon depicts the area disturbed by faulting Figure 46 Representative sparker interpreted profile Figure 47 Overall Spatial Representation of Sediment Types in Tranche A Figure 48 Site slope values (degrees from horizontal) which highlights the valley locations Figure 49 Valley profile B-B (as indicated in Figure 48) Figure 50 Shaded colour depth BSB to Horizon B, interpreted to mark the surface of Unit c Figure 51 Colour banded illustration of bathymetry across Tranche A Figure 52 Zone A as defined from Seabed Features Interpretation Figure 53 Pinger SBP profile of Unit b overlying Unit c with evident seabed valleys Figure 54 Pinger SBP profile of sub-cropping/outcropping Unit c with incised Unit ci Figure 55 Bathymetric image of observed bedforms Figure 56 Zone B as defined from the Seabed Features Interpretation Figure 57 Shaded colour bathymetry with delineated gravel boundary located within a valley Figure 58 Sub-bottom profile showing sandwaves overlaying Unit c and seabed valleys coincident with outcrops of Unit c Figure 59 Zone C as defined from Seabed Features Interpretation Figure 60 Shaded colour bathymetry with delineated gravel boundary located within valley Figure 61 Shallow SBP profile showing surface geology within Zone C as found to the north Figure 62 Shallow SBP profile showing surface geology within Zone C as found in the west Figure 63 Shallow SBP profile showing surface geology within Zone C as found in the southwest Figure 64 Zone D as defined from Seabed Features Interpretation (South) Figure 65 Zone D as defined from Seabed Features Interpretation (West) Figure 66 Zone D as defined from Seabed Features Interpretation (North) Figure 67 Shaded colour bathymetry with the delineated Unit c exposure boundary coincident with a topographic valley Figure 68 Shallow sub-bottom profile showing the sub- outcrop of Unit c Figure 69 Shallow SBP profile showing sub-outcrop of Unit c and correlation with valley topography Figure 70 Profile showing apparent reverberation and acoustic blanking associated with gas presence. 75 Figure 71 Spatial illustration of the high amplitude anomalies observed across the site Figure 72 High amplitude anomalies present GEMS International Group of Companies iv

8 LIST OF TABLES Table 1 Report Volumes...2 Table 2 Dogger Bank Zone Coordinates...9 Table 3 Tranche A Boundary Coordinates (created from rev 1 line plan)...9 Table 4 Met Mast Locations...9 Table 5 Simultaneous Operations Table 6 Geodetic Parameters Table 7 Tidal Heights Table 8 Sediment Transport Definitions Table 9 Wrecks As found Table 10 Observed Depths of Geological Units Table 11 Slope Categories Appendix A Seabed Features Target Database Appendix B Figure Base Map LIST OF APPENDICES GEMS International Group of Companies v

9 GLOSSARY OF TERMS AND ABBREVIATIONS A list of abbreviations that may have been used within the main body of the report λ Wavelength ATT Admiralty Tide Table BSB Below Sea Bed C-O Computed - Observed CAD Computer Aided Design CM Central Meridian CPT Cone Penetrometer Testing DF Dual Frequency DGPS Differential Global Positioning System GSL GEMS Survey Ltd GPS Global Positioning System HAT Highest Astronomical Tide HF High Frequency HSE Health Safety and Environment KHz Kilohertz km Kilometre LAT Lowest Astronomical Tide LF Low Frequency m Metre MBES Multibeam Echo Sounder MRU Motion Reference Unit MSL Mean Sea Level MV Motor Vessel OPM Offshore Project Manager OTS Over the Side QA/QC Quality Assurance / Quality Control QINSy Quality Integrated Navigation System SBP Sub Bottom Profiler SSS Side Scan Sonar SVP Sound Velocity Profile UK United Kingdom UTC Universal Time Co-ordinated UTM Universal Transverse Mercator WD Water Depth (corrected to LAT) WGS84 World Geodetic System 1984 GEMS International Group of Companies vi

10 1. INTRODUCTION 1.1 Project Overview GEMS Survey Ltd. (GEMS) were contracted by Forewind Limited (the Client) to undertake a bathymetric and geophysical survey of the Tranche A development area and two met mast locations (which were later revised) within the Dogger Bank Zone, in addition to a cable reconnaissance from Tranche A to the Yorkshire coastline. The Dogger Bank Zone is located 122km off the coast of Yorkshire and extends to the median line between UK and European waters, as illustrated in Figure 1. Figure 1 Dogger Bank Zone Tranche A is an area of approximately 2000km 2 and lies in the southwest section of the Dogger Bank Zone. The Tranche A and met mast surveys comprised acquisition of side scan sonar, sub-bottom profilers, bathymetric, acoustic ground discrimination (AGDS) and magnetic anomaly data. The cable reconnaissance survey consisted of bathymetric and sub-bottom profilers. GEMS International Group of Companies 1

11 1.2 Objectives The primary objectives of the survey were to produce sufficiently high resolution bathymetric and geophysical data and interpretations to allow regional interpretation for planning and modelling purposes; for met mast design to commence and to provide high quality data to inform further benthic and environmental surveys. These objectives were met by acquisition of the following datasets: Bathymetric data to establish the site depths and bathymetric profiles. This data is also used for acoustic ground discrimination (ADGS), in order to identify different environmental habitats and sedimentation patterns at the seabed to inform the design of the environmental survey. Side scan sonar to identify any seabed features and verify the position of existing infrastructure (e.g. pipelines), with a particular emphasis on identifying hazards to future engineering works, and to inform the design of the environmental survey and of appropriate ground truthing locations. Sub-bottom profiler data in order to characterise in high resolution the stratigraphy of the site to a minimum depth of 50m below seabed. This was achieved by utilising both pinger and sparker profilers, and the characterisation placed particular emphasis on identifying hazards, such as gas charged bodies and faults, to future engineering works, and to identify suitable locations for subsurface sampling. Magnetic data to verify the position of existing infrastructure and identify any unknown ferrous bodies that may pose an obstruction or hazard to future engineering works. Drop down camera transects to allow seabed habitat classification (at met mast locations). 1.3 Document Overview The reporting of this survey campaign has been broken down in to aid accessibility. The full listing of all final reports is available in Table 1. Table 1 Report Volumes Volume Description Document Reference 1 Operations Report: MV Aquarius GSL10109-OPS Operations Report: MV Kommandor Jack GSL10109-OPS Processing and Interpretation Report GSL10109-OPS Geophysical Results Report 5 Original Met Mast W Report GSL10109-GPH-OF002 6 Original Met Mast X Report GSL10109-GPH-OF004 7 Alternate Met Mast W Report GSL10109-GPH-OF006 8 Alternate Met Mast X Report GSL10109-GPH-OF007 9 Cable Route Reconnaissance KP Descriptions GSL10109-GPH-OF003 GEMS International Group of Companies 2

12 1.4 Forewind Client Feedback GEMS Response The following Client Feedback / Response was issued 22nd February 2012: The following client comments have been addressed along with the report and charts. Missing volumes Delivered to client on 27 th January. Volume 1 Operations report M/V Aquarius Volume 2 Operations report MV Kommandor Jack Volume 3 Processing and interpretation report Multibeam Bathymetry Data The multibeam bathymetry data displayed evidence of minor tidal correction discrepancies, the result being stripy looking data grids with differences of over 0.5m identified between some lines (Figure 1). This does not significantly affect the appearance of large scale features, but could make identification of smaller objects such as small wrecks problematic, especially if such features cross between survey lines. Even if such features can be identified, any absolute depth readings taken would be inaccurate. The tidal correction problem also makes the provided gradient analysis spurious, as the only real areas identified by this analysis are the data steps observed between survey lines. Additionally, one file (DBA_425_6070) appears to have data missing, both from the.sd files and the original.xyz file. All depth readings below -32.8m are not present, meaning data from a significantly large area of this section of Tranche A is missing from the data supplied to WA. Please add any abbreviations to the glossary - and refer to LAT Please take section Zone A to Zone D and place it in here with each section split into Bathymetry, Seabed Features including sediment transport and near subsurface soils these should incorporate all the relevant sections of bathymetry and seabed features & sediment transport that are currently in separate sections because there is a huge amount of duplication. For example Figure 7 and 47 are the same! Please move part of section 6 to here call it 'Geophysical and Hydrographic Interpretation' - then section 6.1 Overview with Figure 41 and Figure 44 the zones of similarity are the best way to describe the bathymetry and seabed features of the region. This does not match the 'as supplied' slope information' there are a huge number of artefacts in the data which suggest slopes of in excess of 30 degrees. Please define how the slope information was derived and the filters used to remove the artefacts in order to get this information out Acknowledged and agreed but data reduced by predicted tides resulting in these errors. GEMS now operate using real time tidal corrections. Corrected and to be delivered to client in the final data drop. WD added to glossary. Vertical datum section states that all depths are corrected to LAT. Duplicate Figure removed. Each system / dataset has been introduced prior to the detailed zonal section. For clarity the whole document cannot be discussed in zones as the same features would need to be introduced for each zone, an overview prior to the zones is preferred. This has been discussed with Leo James. Some reconfigurations of the sections have been made to help clarify and avoid duplication. Bathymetry is introduced for the whole area described in water depths of 10-20, 20-30, etc then in detail in the zones of similarity (as above comment). The slope image in Figure 12 is a result of data that has been gridded at a larger (10m bin) interval than in the data issued digitally (1m bin). This explains why there appears to be slopes in excess of 30 degrees in the supplied 5km x 5km block digital data. A comment to this affect has been added to the report to explain the process. Sidescan Sonar Data The sidescan sonar data were provided as.xtf files. Although no survey or operations report were provided, the survey logs indicate that the data were positioned using a mixture of a cable counter and USBL data and the positioning appears to have been included with the data files. A number of problems were encountered with the sidescan sonar data, though judging by the quality of the mosaics created by GEMS (provided as images), it is unclear whether this is a reflection of the data quality itself or is an artefact of how Coda has visualised these particular files. There appears to be a problem with the navigation in All data acquired using USBL positioning but cable counter recorded as standard practice and for verification purposes. The GEMS in house software InfoX was utilised for SSS processing. Online acquisition is set up with the strings necessary for InfoX processing. The processed xtfs were exported from InfoX and have a slightly reduced resolution to that in InfoX. The final navigation used to generate the mosaics is GEMS International Group of Companies 3

13 most of the files which prevents the data being displayed correctly in mosaic. However, this again can be corrected for by a number of processing steps. Although this processing flow does not take a particularly long time to work through for an individual file, the sheer number of files for this project would mean a significant amount of extra processing time would be required to correct all of the files should further interpretation work be deemed necessary. The sidescan sonar data itself is often very spiky, causing problems when attempting to equalise the gains and display the data. Additionally, the speed of sound in water for the survey seems to have been recorded incorrectly, as the data files show a range that is twice that recorded in the survey logs. Additional to the data display problems, the data itself appears of an average quality, with a degree of sea surface noise, interferences from other equipment and snatching visible on many of the records viewed. Further differences in interpretation processes were highlighted during the gap analysis. The first were two anomalies, one a large contact 5m high and the other a depression 7m deep (GEMS ID DBA_S3130 and DBA_S1314 respectively), that could not be identified at their given positions on the sidescan sonar data, nor could they be identified on the multibeam bathymetry data. This suggests either a positioning or measurement error, but either way highlights inconsistencies between two different interpretation processes. identical to that included in the processed xtfs. It is unfortunate that you have to take additional steps to read in the data correctly. If the format of the xtfs is incorrect then please give further feedback so our software developer can address this. Similar corrections have been made during processing. Variable gains believed to be a function of the influence of the towed magnetometer and associated cabling, which causes the fish to list, and also the variable currents experienced. This problem has been identified. The XTF header has been populated with the correct speed of sound 1507m/s however it appears that some packages do not take TWTT into account. The velocity will be halved in the headers for the next issue of the data to ensure that it reads into Coda correctly providing the correct range. Surface noise and cable snatch is apparent in some cases and is unfortunately unavoidable in shallow water (with undamped small cable outs), particularly when operating in marginal weather. Interference is also an issue as the cable out in shallow water is insufficient to provide separation from the Sparker source. These contacts are visible in the high resolution dataset of InfoX however the heights are inaccurate and have been revised to 2.7 and 3.4 for S3130 and S1314, shown as follows (both close to the water column) Furthermore, it is unclear why a large pipeline clearly identifiable on both the sidescan sonar and multibeam bathymetry data was not highlighted by GEMS, though it is present in their gazetteer of magnetic anomalies. Any other anomalous target sizes have been verified. The pipeline and 2 cables have been digitised as part of the geophysical interpretation and has been included in the charts. It appears that this digitisation may have been omitted from the latest shape file delivery. This has now been included. Sub-Bottom Profiler Data The pinger data is of good quality and shows shallow features in high resolution. Despite this, however, one problem was encountered. The Kingdom projects were provided in a number of blocks. Of these, Block 3 appears to be of significantly lower quality than the others, with very little penetration, poorer resolution and a higher degree of background noise. Given the good quality of the other data, it is possible that this is the result of the use of a different processing sequence and is not a reflection of the data itself; though without raw data this cannot be verified. During the review of these data sets, a number of features/layers of potential archaeological interest (e.g. small channels, possible peat layers) appear to have been omitted from the provided interpretation (Figure 3). This would obviously prove problematic For the duration of Block 3 the Aquarius was utilised. The initial set up onboard was a 2x2 pinger array as the moonpool was adapted to carry both the pinger elements and the MBES system. The pinger data was identified to be of poor quality in relation to the Kommandor Jack and the onboard systems were later reconfigured to allow the installation of a 4x4 array, to match the Kommandor Jack. The high data quality, data volume and geological complexity limited the interpretation of the dataset to the critical lithostratigraphy. Attempts were made to identify shallow GEMS International Group of Companies 4

14 were this interpretation solely used for an archaeological review. It is understood that the provided interpretation was not the final version, though the frequency with which such features were omitted suggest they would also be missing from the final interpretation, as whilst they are of archaeological importance they may not be critical to defining the lithostratigraphy and associated geotechnical attributes. Following investigation of the GEMS geophysical survey report, the major concerns regarding the interpretation presented are a series of channels that do not appear to have been identified. Sub-Surface Geology Interpretation Unit b A number of instances of missing data are marked on the unit b isopach provided. However, there is no mention of how much data is missing. This information should be contained within the report. Other areas in unit b are marked Uninterpretable in record. GEMS define unit b as Holocene sediments. In this area, Holocene sediments are generally sandy in nature (see BGS Swallow Hole and California Quaternary Geology charts). Figure 64, in the GEMS geophysical survey report, presents the interpreted base of unit b. An area of approximately 170 km2 in the central east of the Tranche is labelled Horizon B main lines not interpretable. The relevant isopach shapefile provided, shows large areas where unit b has not yet been interpreted by GEMS. On page 65 of the GEMS geophysical survey report it states that: The depth of the horizon in the centre of Zone A is beyond the penetration of the pinger and can be seen as a very shallow horizon in the Sparker data. If this is the case then unit b should be interpreted from the sparker and not the pinger data. As it stands there is no information concerning the thickness of the top sedimentary unit for a large proportion of the Tranche. It seems likely from reading the zonal survey and geotechnical reports that these areas marked uninterpretable in record correspond to the shallow channel system observed by Gardline and the sandy unit recorded in geotechnical samples recovered by Fugro. Horizon B recognised as likely Bligh Bank Sands only top section of the Holocene sequence included within GEMS interpretation - additional work has been completed on Holocene sands section report and latest image included for reference. Unit c Figure 67, in the GEMS geophysical survey report, displays the interpretation of Horizon C (the interpreted base of unit c ). The stated scale is Depth in metres. It is assumed that this refers to depth below seabed (mbsb). However, this requires clarification. It is also noted that the displayed depth range is 15 to 60 m and that at times the horizon is interpreted to be within <1 m of the seabed. These two ranges are contradictory. If the base of unit c shallows to within 1 m of the seabed then it follows that it must be present between 15 and 1 m. However, this horizon does not appear to have been interpreted at these depths. It is also noted that Horizon C (base of unit c ) is interpreted as not present over an area of approximately 180 km2 in the west of Tranche A. From investigation of the isopach C shapefile, provided, it is apparent that Horizon C is interpreted at between 25 and 35 mbsb on the boundary between presence/absence of unit c. This implies that, in this location, unit c is truncated at depth and replaced in the sedimentary column by another unit. GEMS explain this by suggested glacial faulting (see p. 67). However, the OMM geologist is sceptical of this interpretation for a number of reasons: not least because in the zonal survey, Gardline identify a major channel at this location. In any case, the interpretation presented by GEMS is not consistent with truncation via faulting. features but we appreciate we may have omitted the interpretation of features critical to archaeological review. Further insight into archaeological surveys has been beneficial to GEMS development. In future projects more time will be set aside to achieve this. The missing lines are to be identified clearly in the charts so that remaining interpretation gaps correspond to uninterpretable alone. Data has been interpreted in a conservative way to try to avoid misinterpretation, in areas where horizons are unclear. This has a significant effect on the areas acquired with the 2x2 array. It is acknowledged that Forewinds have continued the interpretation in these areas. Attempts were made to use the sparker data to complete the pinger interpretation however the wide seabed pulse, which overwrites the data, and the increased wavelength of the data made accurate delineation too difficult to continue. See previous comment regarding shallow features. GEMS acknowledge this discrepancy in light of the new interpretation and geotechnics, where horizon B now represents the likely base of the Bligh Bank Sands and Unit A the base of the Holocene sediments. A comment in the report has been added to explain. The scales on all of the depth below seabed images have been checked and tally with the table. Depth below seabed has been stated in the vertical datum section of the report. Faulting of the glacial deposits is observed as most clearly shown in Figure 41. This has now been identified by the BGS study. It is possible that Horizon C occurs at shallower depths but the record is difficult to interpret without geotechnical input. 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15 From the data presented in the GEMS geophysical survey report, it is noted that the other units interpreted as being present in this location are b, e and f. Unit b is interpreted as being relatively shallow (generally 2 4 m, though with a maximum thickness of 14 m in the far west). It is difficult to assess the thicknesses of units e and f as OMM have not been provided with isopachs for these. However, using values based on figures 68 and 69 in the GEMS geophysical survey report, unit e has a minimum depth value of 100 mbsb and unit f seems to have a depth of somewhere between 15 and 50 mbsb (from the symbology used in Figure 69 it is very hard to tell). GEMS interpret unit c as the Dogger Bank Formation, unit e as the Yarmouth Roads Formation and unit f as the Swarte Bank Formation. Of these, the Dogger Bank Formation is the most recent, followed by Swarte Bank Formation, with the Yarmouth Roads Formation the oldest. Again the scales on all of the depth below seabed images have been checked and tally with the table. Unit e is in fact the Swarte Bank formation and Unit f the Yarmouth Roads. BGS checking/re-mapping GEMS horizon C within Tranche A First activity was to identify large buried mound that sits atop horizon C (Fig 1) and to separate it from actual horizon C. Feature is clearly distinct. Unfortunately there is no core atop the mound to test its composition. o We ve made a separate, coarse interpretation of this feature and removed it from the GEMS Horizon. (Fig 2) Picking discrepancies: The next task was to check the GEMS horizon and try and fill in blank areas where the interpretations had not made. This analysis revealed a fair amount of inconsistency in the GEMS pick but also the complexity of mapping the base Dogger Bank. Rather than correct their horizon, we decided to create a new coarse (every 5-10 lines) in the interest of time. o This horizon is intrinsically difficult to map due to regular interference of seabed multiple. o Summary: We believe that what they have mapped as C is largely the Top of Egmond Ground (EG), rather than base Dogger Bank (DB). Where they have mapped base Dogger Bank, they have not mapped the top Egmond Ground. We have gone back and mapped this horizon in this area (Fig 3). We suggest that the base DB is often a weaker reflector than top EG. According to several boreholes (eg 1014), there is an irregular sand body sitting between what is presumably EG and DB. Laterally, it is of varying thickness 0-20m). (Fig 4). So where this unit is absent (or can t be distinguished on seismic), the GEMS C horizon is the base DB. We have begun to coarsely map the base DB, where GEMs have only mapped the top EG (Fig 5). I ve done a quick difference map (Fig 6) Colour scheme on seismic interpretation: Pink (GEMS horizon C); Purple (BGS interpreted top Egmond Ground); Red (BGS reinterpreted base Dogger Bank); Yellow (Seabed and seabed multiple); light blue (GEMS D); dark blue (GEMS E - Swarte Bank). Channels: Sometimes GEMS pick channels dropping off top EG, and sometimes they draw straight line across. In our re-mapping exercise, we will not incorporate channels into our re-interpretation of the base DB. Blank Areas: We broadly find that areas they have not mapped are either due to presence of channels, or deformation in the DB which has deformed underlying units as well. As a note, this deformation of underlying units is quite common. GEMS value the feedback received from Forewinds. The potential Esker mound is of particular interest and was not reported during the interpretation of the main stratigraphic units. GEMS appreciate that the interpretation is evolving and that mistakes have been made due to the complexity of picking the base of the Dogger Bank. An additional explanation has been added to the report to reflect this. We find often that it is possible to coarsely trace across these areas joining reflectors either side. But it should be noted that the geotechnical properties within these zones will almost certainly be different from undisturbed strata. GEMS International Group of Companies 6

16 The following Client Feedback (to Rev.2 of this report, February 2012) was subsequently received 8 th October 2012, with comments incorporated into the current document. Document Geophysical Survey Report - Document Review GEMS International Dogger Bank Tranche A:- Acoustic and Geophysical Survey Geophysics Results Report Volume 4 of 9 Document No. Revision 2:- Issue to Client after review Date of issue 17 th Feb By:- RAB Date:- 5 th October 2012 Approved:-LJ Date:-8 th October 2012 Overall Comments There has been considerable development of the geological model, however what is presented is fair reflection of what is present and has contributed significantly to the development of the model. There needs to be a consistent approach to the report as regards naming conventions, text and Figure presentation. Page Section Location Comment Action General When discussing directions e.g. section Correct throughout South East write as southeast (all one word). Other points of the compass should be written as south and SSE etc. General All figs that include sonar data need an along Add throughout. track and cross track scale. Mosaic data examples will need a scale. General All figs that include examples of the seismic data Add where applicable. need a vertical scale in metres. At the very least it needs to be annotated what the vertical scale is(two way time but preferably meters). 2 (new) 1.4 New section Can you insert the document dated 22 nd Feb 2012 as section 1.4 and give it the same title ie.. Add. Response is acknowledged. Forewind Client Feedback GEMS response vii glossary WD Water Depth (corrected to LAT) add rd para. 1 st Sub-bottom profiles should read Sub-bottom correct sentence profilers st para Survey data for Alternate Mast West (previously correct W) nd para Survey data for Alternate Mast East (previously correct X) rd para, last.but stiff clay. correct sentence New section Insert section title Stiff clay outcops add New section Insert section title Stiff clay and gravel add rd para, 1 st Change boulder clay to stiff clay correct sentence New section Insert section title Mixed sediments add New section Insert section title Gravel patches add Table 8 Add λ to the Glossary as Wavelength add 29 Fig 25 Add an X to mark location of figs 26 and 27 and add annotate relevant X st para, 2 nd Sub bottom profiler dataset but should be correct sentence changed to and nd para,2 nd Anomaly amplitudes should be changed to correct sentence magnetic anomalies 32 Fig 29 SEAL should be in capitals Correct also in List of Figs page iv nd para, 2 nd Anomaly amplitudes should be changed to correct sentence magnetic anomalies rd para, 2 nd Anomaly amplitudes should be changed to correct sentence magnetic anomalies th para Place these details into a table. Along with as amend given and as found positions st para, 1 st 3 identified wrecks discussed in section 0 correct GEMS International Group of Companies 7

17 Page Section Location Comment Action sentence should be section st para Move to next page so it goes with the trawl scar amend figs Table 9 In the coloumn header Height. (Depth) should be correct changed to (m) 41 6 Fig 37 Change cartoon to schematic needs to be amend done in the Figure list as well on page v nd para, 1 st Delete the s on the end of Forewinds correct sentence rd para, Shouldn t it be Dave Long not Brian Long? Check. last sentence rd para. Formation should have a capital F Correct all nd para. 2 nd 2 examples were boulder clay should read stiff correct sentence clay nd para. 3rd Change higher water depths to greater water correct sentence depths rd para. Beginning the relative benign. Move so it amend comes after Fig50 56 Fig 50 Add note as in fig40 regards uninterpretable add section nd para Mention Botney Cut channels at the surface in add Zone A st Para 2 nd Beginning The average amplitude. Remove amend sentence this but ensure it is covered in the SBF section nd para. 2 nd Beginning the bathymetry indicates amend sentence Remove this but ensure it is covered in the bathy section nd para. 5 th Remove the word thin from in front of veneer, amend sentence a veneer is by definition, thin th para Beginning few sonar contacts Remove this amend but ensure it is covered in the SBF section nd para 1 st Rewire to focus less on bathy.suggest amend and 2 nd sentences Sandwaves are present only in 20% of the zone, mainly in the shallow areas st Para Beginning few sporadic sonar contacts amend Remove this but ensure it is covered in the SBF section rd para, 2 nd Beginning the average amplitude Remove amend sentence this but ensure it is covered in the bathy section rd para, 1 st, again oriented with the flow regime should be correct sentence orientated st Para Beginning There are few. Remove this but amend ensure it is covered in the SBF section. 71 Check page numbering as there are two page Amend 71 s nd para, 2 nd sentence the interpreted Dogger Bank Formation capital F correct GEMS International Group of Companies 8

18 2. SCOPE OF WORK 2.1 Site Definition Tranche A The Dogger Bank Zone, and Tranche A are defined by the coordinates (WGS 84, UTM 31N) in Table 2 and Table 3. Easting Table 2 Dogger Bank Zone Coordinates Northing Table 3 Tranche A Boundary Coordinates (created from rev 1 line plan) Easting Northing Met Mast Locations The Met Mast locations are 1km by 1km surveys based around the locations in Table 4, provided in WGS84, UTM Zone 31N. Table 4 Met Mast Locations Met Mast Easting Northing Original Met Mast W Original Met Mast X Alternate Met Mast West (previously W) Alternate Met Mast East (previously X) GEMS International Group of Companies 9

19 2.1.3 Cable Route Reconnaissance Cable route reconnaissance lines were run during periods of marginal weather when work on Tranche A was not possible. Lines were run at arbitrary 5km intervals within the Project One corridor. No lines were run within the 12 nautical mile limit from the UK coast. 2.2 Line Plans Line plans were provided by RPS, a consultant to Forewind, and were designed to run perpendicular to the expected strike of the geology across the region. The line orientations matched the Zone Wide Survey (ZWS) performed in spring Tranche A Survey Main lines were orientated at 43 /223 and spaced at 100m intervals. Cross lines were orientated at 133 /313 and spaced at 500m intervals. All systems were logged concurrently during the single pass survey Met Mast Surveys (Original) Surveys were based on a 1km square orientated in-line with the Tranche A mainlines. Main lines were orientated as 43 and spaced at 100m intervals. Cross lines were orientated at 313 and spaced at 150m intervals. All systems were logged concurrently during the single pass survey. A more detailed magnetometer survey was conducted over the 100m immediately surrounding both proposed locations, with line spacing at 10m intervals for both main and cross lines. Environmental surveys were performed via drop down camera work at locations selected from the side scan sonar Met Mast Surveys (Alternate) Survey data for Alternate Met Mast West (previously W) was extracted from the main Tranche A survey data, with line spacing as per Tranche A (100m main lines, 500m cross lines). Survey data for Alternate Met Mast East (previously X) was acquired as a separate survey as it is outside of the Tranche A limits. The 1km square was orientated in-line with Tranche A mainlines, and line spacing as per Tranche A. All systems were logged concurrently during a single pass survey. No separate magnetometer survey was performed. No environmental investigations were performed. GEMS International Group of Companies 10

20 2.3 Equipment A full list of equipment is available in the operations reports; equipment types varied slightly by vessel but the following types of systems were run Seabed Topography Information on seabed topography was acquired using the following systems: Singlebeam Echosounder R2Sonic 2024 Multibeam Echosounder SEA SWATHplus interferometry system Seabed Features Information on seabed features was acquired using the following systems: Edgetech 4200 FS multi-pulse side scan sonar G882 or SeaSpy Magnetometer Geophysics Information on geophysics was acquired using the following systems: GeoAcoustics Hull Mounted Pinger Geo-Spark 800 Geo-Resources sparker (Geo-Spark 200 as redundant spare), with a TL3 multichannel recording system. 2.4 Simultaneous Operations Both the MV Kommandor Jack and the MV Aquarius undertook acoustic and geophysical operations as part of the Tranche A surveys. Tasks were completed as per Table 5. The terminology used to describe the areas completed by the vessels was Blocks 1 through 4. The Aquarius completing the northern most Block 1 and central Block 3 and the Kommandor Jack an adjacent central Block 2 and southern most Block 4. This is illustrated in Figure 2 and Figure 3. GEMS International Group of Companies 11

21 Table 5 Simultaneous Operations Single Pass Survey Separate Survey Singlebeam Echosounder Multibeam Echosounder SEA Swath Side Scan Sonar Magnetometer Pinger Sparker Environmental Magnetometer Tranche A Mainlines Tranche A Crosslines Original Met Mast W Original Met Mast X Alternate Met Mast W Alternate Met Mast X Cable Route Reconnaissance KJ/AQ KJ/AQ KJ/AQ KJ/AQ KJ/AQ KJ/AQ KJ/AQ - - KJ (infill only) KJ KJ KJ KJ KJ - - KJ - KJ KJ KJ KJ KJ AQ KJ KJ - KJ KJ KJ KJ KJ AQ KJ KJ/AQ KJ/AQ KJ/AQ KJ/AQ KJ/AQ KJ/AQ KJ/AQ - - AQ AQ AQ AQ AQ AQ AQ - - KJ KJ KJ KJ = MV Kommandor Jack AQ = MV Aquarius GEMS International Group of Companies 12

22 Figure 2 Lines Run by Kommandor Jack Figure 3 Lines Run by Aquarius GEMS International Group of Companies 13

23 3. PROJECT CONTROL 3.1 Horizontal Datum Geodetic parameters were specified by Forewind and entered into the online (and other relevant systems) as displayed in Table 6. All Easting and Northings are provided in the working projection (UTM 31). Table 6 Geodetic Parameters Working Spheroid Datum: WGS84 Projection: Spheroid: WGS84 (GRS1980) Conversion Factor to metres: Working Projection Universal Transverse Mercator Zone Semi-major, a: Longitude Origin: E Semi-minor, b: Latitude Origin: N Flattening, 1/f: False Easting: Eccentricity, e 2 : False Northing: 0 Comments/notes Scale Factor on CM: Units: m 3.2 Vertical Datum The vertical datum for this project is LAT using predicted tides. Twenty seven fictional stations were spaced across the site using co-tidal charts on predicted tide from the River Tyne station. The following was supplied to the vessel to enable this to take place: UKHO Admiralty Tide Table NP UKHO Admiralty Chart 5058 (Co-Tidal / Co-Range North Sea) QINSy Software Figure 4 Grid of fictional tidal stations Predicted tide was calculated for the survey period using harmonics for River Tyne which was the closest primary port to the survey area and also proved to be the most suitable station, as it provided the largest GEMS International Group of Companies 14

24 tidal range for the co-tidal model calculations. Chart 5058 was then used to calculate the Mean High Water Interval (MHWI) and Mean Spring Range (MSR) for each fictional station. Adjustments for the twenty seven fictional stations using the predicted tide at River Tyne were then made and a linear co-tidal model was built in QINSy which was then applied to the data. LAT and HAT tidal values at each fictional station can be found in Table 7 below. All figures quoted below are in relation to MSL. Table 7 Tidal Heights Station Number Easting Northing LAT (m) HAT River Tyne GEMS International Group of Companies 15

25 Figure 5 shows the relationship between LAT and HAT throughout the site depicted in contour form. Again all heights are quoted in relation to MSL. Figure 5 Tidal Level Contours Sub-bottom profiler depths are provided with respect to the seabed. Values for all horizons are stated in metres below seabed (mbsb). 3.3 Time Datum All systems have been interfaced to the DGPS system, with critical systems being linked to the 1 Pulse Per Second (PPS). All systems are set to log in UTC. Daily Progress Reports (DPRs) are in Local Time (BST). 3.4 Units Datum All systems are set to log using the SI (metric) system. All units in this report are in SI units unless quoted otherwise. GEMS International Group of Companies 16

26 4. BATHYMETRY The bathymetric data set was collected with an R2 Sonic 2024 Multibeam Echosounder interfaced through QINSy and processed using Fledermaus. The following sections provide a brief introduction to the Bathymetry observed across the entire Tranche A site. The bathymetry is then discussed in more detail in the Geophysical and Hydrographic Interpretation, Section 7, where the Tranche A site has been split into similarity zones A through D. 4.1 Depths Figure 6 shows the Tranche A site, colour banded by depth (LAT), as follows: < 20m (red) 20 to 30m (green) 30 to 40m (blue) > 40m (white) Figure 6 Colour banded bathymetry overview of Tranche A The following sections outline the major bathymetric features and characteristics associated with the aforementioned depths bands defined across the site. GEMS International Group of Companies 17

27 4.1.1 Less Than 20m WD The areas of less than 20m WD predominantly reside in the south and west of the Tranche A site at the summit of the valley forms which can be observed in the locality. Sandwaves are occasionally observed in depths less than 20m. Such occurrences are illustrated in Figure 7 and are centred on E, N (19.87m WD) and E, N (19.94m WD). Figure 7 Shallow sandwaves observed in the bathymetric dataset. GEMS International Group of Companies 18

28 These sandwaves are predominantly symmetrical in cross section as illustrated in Figure 8. Figure 8 Bathymetric profile across symmetrical sandwaves. Centred on E, N. GEMS International Group of Companies 19

29 m-30m WD Depths of 20-30m dominate the site, as illustrated by the green areas of Figure 6. There is a large low relief area of seabed in the Southeast of Tranche A, which shows depths ranging from 20-25m as outlined in Figure 9. 1 km Figure 9 Low relief flat area, with WD 20-25m observed in the East of the Tranche A site. The sandwaves observed across the site are most dominant in this water depth range. The nature of the seabed in WD 20-30m is of relatively low relief in comparison to the features observed at deeper depths. GEMS International Group of Companies 20

30 m-40m WD Depths of 30m-40m can be observed towards the base of the valley features to the southeast and northwest, as displayed in Figure 10 and Figure 11 respectively. Figure 10 Depths of 30m-40m in southeast of site, highlighting the base of the valley forms. Figure 11 Depths of 30-40m along northwest boundary, delineating the base of valley forms GEMS International Group of Companies 21

31 5. SEABED FEATURES Side scan sonar and magnetometer data were reviewed in conjunction with the bathymetric datasets in order to analyse the seabed characteristics. These characteristics include the following: Interpreted sediment type Sedimentary bedforms Sonar contacts Magnetometer contacts Potential hazards at the seabed Side scan sonar data was acquired using an Edgetech 4200MP towfish. Magnetometer data were acquired with a Marine Magnetics SeaSpy or GeoMetrics G882 magnetometer. The magnetometer was towed directly behind the side scan sonar towfish with a layback of 10m. Correlations were then made between identified magnetic anomalies and the side scan sonar record. The figures provided in this and subsequent sections have been provided with a centre position for reference. An accompanying base map to show these locations is provided in Appendix B for spatial reference to the Tranche A site. GEMS International Group of Companies 22

32 5.1 Sediment Overview Sediments were classified using the character and acoustic reflectivity exhibited in the side scan sonar mosaic record. No ground-truthing was carried out during survey operations. Seabed sediments have been classified using an adapted Folk Classification (R.L. Folk, 1954) as shown in Figure 12. Additional major sediment types of Tranche A are also shown at the base of the Folk triangle which have been agreed with RPS QC representatives. The major sediment types are discussed in this section but are then discussed spatially in the Geophysical and Hydrographic Interpretation, Section 7, where the Tranche A site has been split into similarity zones A through D. Figure 12 Adapted Folk Sediment Classification The stiff clay category has been revised for the second issue of the report and charts. Boulders were not detected in the sub bottom record, nor the follow up geotechnical campaign. When observed at the seabed it is cobbles which dominate the course sediments observed at the seabed not boulders, which are occasional. For these reasons it is therefore no longer classified as a Boulder Clay but stiff clay with cobbles and boulders (or varying frequency). GEMS International Group of Companies 23

33 The following sonar record waterfall displays and mosaics are indicative of the acoustic characteristic of the sediment classifications. For scale the blue range lines are 20m apart. The along track scale is the same Stiff Clay Outcrops 20m N Figure 13 SSS record of stiff clay with frequent cobbles and occasional boulders. Line DBA10AQM140901A; centred on E, N Figure 13 typifies an acoustically rough area of seabed classified as stiff clay with frequent cobbles and boulders, where reflectivity varies greatly over a short range, giving an overall high relief. As can be observed in this Figure there are frequent patches of sand and gravel, too small to be digitised, which reside within the stiff clay areas. Both boulders and cobbles of differing frequency are observed within these areas. The stiff clay areas have been split into frequent and occasional depending on the seabed surface occurrence of cobbles and boulders. The frequent areas have numerous point contacts within them; the majority of which are boulders and these have been chosen due to their appreciable magnitude, readily measurable in the side scan sonar record. GEMS International Group of Companies 24

34 Although the stiff clay is of highest relief in the sonar record it is sand which is the main sediment classification of the Tranche A site, covering over 85% of the total area. Figure 14 illustrates the predominance of sand (yellow) in comparison to the remaining sediment types in black. Figure 14 Predominance of sand across the Tranche A site GEMS International Group of Companies 25

35 Figure 15 shows the acoustic character of the interpreted sand, of low uniform reflectivity. 20m N Figure 15 SSS record of sand Line DBA10AQM145; centred on E, N It is to be noted that some acoustic noise from the Sparker system can be observed at the distal ranges of the record due to their close proximity in shallow water. GEMS International Group of Companies 26

36 5.1.2 Stiff Clay and Gravel Figure 16 shows the acoustic character of the interpreted stiff clay (with occasional cobbles and boulders) towards the bottom of the Figure but also the medium reflectivity acoustic return representative of gravel to the centre and top. N 20m Figure 16 SSS record of stiff clay (occasional) and gravel Line DBA10KJM155501A; centred on E; N The gravel can be smooth in nature however as in the above example, we see varying returns indicative of megaripples. The strong variation in reflectivity of the troughs and peaks of these bedforms may indicate that finer material populates the peaks leaving the courser material behind in the troughs. Megaripples mainly reside in areas of gravel and in particular on the eastern margins of the observed gravel areas. GEMS International Group of Companies 27

37 Megaripples can be observed to populate large regions, the largest of which is in the east of Tranche A, covering an area over 50km². A large area of megaripples can be observed in the side scan sonar mosaic in Figure 17. N c. 1 km Figure 17 Megaripples observed in the SSS mosaic Mosaic with bottom left corner at E; N; 2km field of view The megaripple transport direction is predominantly NNW to SSE, although this is discussed more thoroughly in the Sediment Transport, section 5.2 of this report. Evidence for megaripples can also be found in the stiff clay and mixed sediment type classifications, but are less dominant in the record. These instances are typically more localised. GEMS International Group of Companies 28

38 5.1.3 Mixed Sediments The far left of Figure 18 indicates evidence of the occurrence of megaripples in a predominantly mixed area of seabed. 20m N Figure 18 SSS record of mixed sediment classification Line DBA10AQM1380; Image centred on E, N The complex nature and mixture of the interpreted seabed sediment types has led to areas being classified as mixed, with each sediment type being identified with roughly equal percentages. These areas portray the characteristics of the sand, gravel and stiff clay, none of which dominate the record. GEMS International Group of Companies 29

39 Another example of a largely mixed sediment classification is illustrated in Figure 19. N 20m Figure 19 SSS record of mixed sediment classification Line DBA10AQM1536; Image centred on E; N In the above instance there is equal evidence for gravel, sand and stiff clay in accumulations too small and/or complex to be digitised individually. This Figure is therefore representative of mixed sediment. GEMS International Group of Companies 30

40 5.1.4 Gravel Patches Gravel patches can be observed across the Tranche A survey area. Figure 20 and Figure 21 are representative of gravel patches amongst large regions of sand. Figure 20 SSS record of isolated gravel patches Line DBA10AQM1454; Image centred on E; N N N 20m c. 1 km Figure 21 SSS mosaic of gravel patches Mosaic with bottom left corner at E; N. Field of view: 3km GEMS International Group of Companies 31

41 The gravel patches across the site are typically infrequent, indistinct and with little or no evidence for bedforms. Areas where bedforms have not developed may indicate that these patches comprise a more compacted, harder sediment. 5.2 Sediment Transportation As noted in the previous section, bedforms are observed across the Tranche A survey area due to the transportation of sediment at the seabed. The majority of the bedforms identified comprise megaripples residing in the interpreted gravel areas however sandwaves are also evident in the side scan sonar and bathymetric datasets. The sandwaves are visible in the side scan sonar mosaic due to the apparent change in sediment type at the peaks of each sandwave resulting in a significantly higher acoustic reflectivity in comparison with the ambient seabed. The presence of sandwaves was confirmed by their apparent relief evidenced in the bathymetric data. Bedforms are classified using the standard definitions displayed in Table 8. Table 8 Sediment Transport Definitions Terminology Ripple Megaripple Sandwave Definition Undulations (<0.5m λ) produced by fluid movement (waves and currents) over sediments Undulations (0.5m to 25m λ) produced by fluid movement (waves and currents) over sediments Undulations (>25m λ) produced by fluid movement (waves and currents) over sediments Bedforms typically exhibit a low amplitude of less than 0.5m. Currents are strong enough to move and potentially erode the interpreted sand and/or gravel grade material. Although no major erosional features or scours have been observed, the underlying stiff clay has been exposed in bathymetric lows where there is no surficial sediment cover. GEMS International Group of Companies 32

42 Megaripple transport direction (observed in the side scan sonar record) is predominantly NNW to SSE, which is thought to be a function of the strong North to South tidal flow regime operating in this area. However, the transport direction does vary locally across the survey area, along with the wavelength of the megaripples, which varies over a 100m range and in particular at the boundary of the areas they occupy, as displayed in Figure m B N A N N Figure 22 Megaripple variations Line DBA10AQM1480; Image centred on E; N The megaripple wavelength can be observed to change to the west from 1-1.2m at point A in Figure 22 to 1.5-2m at point B. The transport direction also noticeably rotates to an orientation closer to northsouth rather than the general NNW to SSE direction observed across the site as a whole. This is thought to be a function of the dynamic seabed currents acting in the area. The dynamic nature of the evolving bedforms has been observed due to adjacent or repeated survey lines being performed over a time period of up to 1 month apart. Figure 23 and Figure 24 show the migration of fine sediment over an 18 day period, from the lee slope of a sediment build up associated with megaripples. GEMS International Group of Companies 33

43 20m N Figure 23 SSS record of sediment migration, 03 December 2010 Line DBA10AQM145701A; Image centred on E; N 20m N Figure 24 SSS record of sediment migration, 21 December 2010; Line DBA10AQM145701B; Image Centred on E; N GEMS International Group of Companies 34

44 In Figure 24 fine sand, as identified by its very low reflectivity, is observed to have migrated locally to the north east, leaving behind the coarser gravel grade material characterised by an increased reflectivity. The predominant flow regime is therefore assumed to be towards the north east on this occasion. As shown in Figure 24, megaripples often populate large swaths or ribbons of gravel, and when compared with the bathymetric datasets many of these swaths form symmetric sandwaves, making definitive transport direction measurements, whether towards the north east or the southwest, of many of these sandwaves difficult. The megaripples are superimposed upon these sandwaves predominantly at an orientation approximately perpendicular to the sandwaves. These sandwaves are found to have a wavelength averaging 115m, overall wavelengths ranging from m and amplitudes of m (average 0.6m). The superimposed megaripples that were observed within the geophysical data sets were not identified in the bathymetric data, but the bathymetry did identify sandwaves that are not easily visible in the geophysical data. Clearly depicted sediment changes are also not discernible in the bathymetry. Figure 25 below shows the different areas of sandwaves throughout the site. The sandwaves are found to occur mostly in depths of 20-25m on the edge of valleys, as illustrated in Figure 26 and Figure 27. Figure 25 Areas of sandwaves identified in bathymetry (encircled in black) GEMS International Group of Companies 35

45 North South Figure 26 Sandwave direction, wavelength and amplitude Image centred on E; N, 20m WD Figure 27 Sandwave direction, wavelength and amplitude Image centred on E; N, 25m WD Further study needs to be carried out to understand the sedimentary processes acting across the wider Dogger Bank area, to identify and analyse any other trends and phenomena. Seasonal variation is also likely to add to this dynamic sedimentary process. GEMS International Group of Companies 36

46 5.3 Existing Infrastructure Three cables and one pipeline can be observed in the Tranche A survey area. These linear features can be observed in the side scan sonar record when at the seabed, by parabolic returns in the pinger sub bottom profiler dataset and most clearly in the magnetometer record. 696 magnetometer contacts have been identified across Tranche A. Of these, 176 delineate the position of the PL1570-Shearwater to Bacton SEAL 34" gas pipeline. Magnetic anomalies range from nT with an average of 121nT. The as found pipeline position appeared to lie approximately 80m east of the client provided database position, as shown in Figure 28 but this was attributed to an incorrect Geodesy ED50 and the revised database provided by the client matches the as found position. Superseded database position Figure 28 Magnetometer detected gas pipeline Centred on E, N The anomalies above and below the background magnetic field are denoted by the red and green peaks. The peaks or inflections were picked by the onboard geophysicist and represent the interpreted as found pipeline position. The as found positions have been depicted in the charts. GEMS International Group of Companies 37

47 The pipeline was clearly detected, when at the seabed, by side scan sonar and these occurrences have been digitised in the seabed features chart. Of the km of pipeline within the survey area, 9.685km can be found at the seabed. A side scan sonar image across the pipeline is displayed in Figure 29. c. 1 km Figure 29 SSS mosaic of the detected SEAL gas pipeline Image centred on E; N 152 magnetometer contacts delineate the position of the UK-Germany 6 cable. Magnetic anomalies range from 5-40nT with an average of 15nT. The maximum distance between adjacent picks is 650m with picks closely matching the provided database position, which is therefore believed to be reliable. 96 magnetometer contacts delineate the position of the Tata North Europe cable. Magnetic anomalies range from 4-37nT with an average of 11nT. The distance between adjacent picks is significant, reaching a maximum of 2.3km towards site centre however; picked values closely match the provided database positions, helping to validate the position between anomaly picks. There is just one possible magnetometer hit on the out of service UK-Denmark 4 BT cable Contact DBA_M2208 at 22nT although this could be a chance contact which falls close to the provided database position. This cable is likely to have deteriorated, carries little or no armour, or is buried too deep to be detected with the magnetometer. Wellhead (status) As-found E As-found N As-given E As-given N Difference (from As-given) Anomaly (nt) 43/05-1 (abandoned) m S (185 ) 743nT 43/10-1 (active?) m SW (242 ) 79nT 43/02-1 (abandoned) Not detected 43/03-1 (abandoned) Not detected 44/06-1 (abandoned) Not detected GEMS International Group of Companies 38

48 5.4 Contacts Magnetometer Point Contacts The remaining 271 magnetometer contacts which are were not related to infrastructure are spread across the entire area and 18 of these are associated with side scan sonar contacts of various classifications, including the 3 identified wrecks discussed in section There are some localised concentrations of the remaining magnetometer contacts which may suggest that the results have been influenced by local geology, bathymetry and deployment geometry (including proximity to the survey vessel) as discussed in the later part of the processing methodology of GSL10109-OPS Side Scan Sonar Contacts There have been a total of 1914 side scan sonar contacts identified across Tranche A. Of this number, 856 sonar contacts were classified as boulders or boulder clusters, thought to be of glacial origin. Boulders and boulder clusters are present throughout the area, although within the areas of significant megaripples their presence is lessened. Although it was not possible to target all boulders across the site, boulders dominant in the record were picked as Isolated Boulders, as illustrated in Figure 30, or Boulder Clusters as shown in Figure 31. c. 10 m Figure 30 Isolated Boulder (3.1x1.5x0.7m). Line DBA10AQM1073, centred on E, N GEMS International Group of Companies 39

49 c. 10 m v Figure 31 Boulder Cluster (image extent 50 x 90m). Line DBA10AQM1021, centred on E, N. GEMS International Group of Companies 40

50 Other non-geological contacts in the area include trawl scars, which were observed towards site centre and the Southeast (Figure 32 and Figure 33). These appear different to the sand bars and megaripples by the character of the light and shadow return. The trawl scars do not appear to be steep sided suggesting that they are not recent and/or have been recently reworked. Other than trawl scars, there was little evidence of fishing activity within the Tranche A; there were no disruptions to the survey due to fishing activity throughout the course of operations. 20m Figure 32 Trawling activity in evident in gravel sediment Line DBA10AQM104201A; Image centred on E; N Figure 32 has been interpreted to be representative of trawling activity in this region due to the engrained markings in megarippled gravel. GEMS International Group of Companies 41

51 Trawl scars are observed mainly in areas where there is an increased gravel content as displayed in Figure 33. c. 50 m Figure 33 Trawl scar termination at sediment boundary. Line DBA10AQM104201A; Image centred on E; N GEMS International Group of Companies 42

52 5.4.3 Observed Wrecks 3 wrecks were provided in the SeaZone database; Unidentified ( E; N), U66 ( E; N) and William and John ( E, N). No wrecks were discovered in the immediate vicinity of these provided in the SeaZone database. 3 additional wrecks were found at the seabed in the side scan sonar record. These wrecks were also identified in the bathymetric data and magnetometer data, and hence have associated magnetometer contact ID s. Primary positioning is taken from the bathymetric data. Table 9 outlines the wreck attributes, including their least depths. Wreck ID (SSS) Wreck ID (Mag) Easting Northing Table 9 Wrecks As found Least Depth (m LAT) Length (m) Width (m) Height (m) Identified from Admiralty / Seazone Data No ; No ; No The following figures show bathymetric and SSS data examples of wrecks GEMS International Group of Companies 43

53 Figure 34 Wreck (ID 1000) identified in the bathymetric data (top) and SSS record (bottom) Images centred on E; N (6x Exaggeration for bathymetry). SSS record from line DBA10KJM118501A. Wreck ID 1000 is 19.5km from the database position (bearing 283 ) of U66 however the character of the wreck suggests it may be U66. The vessel specification yields a vessel length of 70m, less than the SSS measured length, however vessel break up, debris, seabed scaring and sedimentation could account for GEMS International Group of Companies 44

54 this. There appear to be features within the target which could represent railings, which are set well in from the external limits of the vessel, as commonly observed on a U66 due to side flotation tanks. Figure 35 Wreck (ID 1001) identified in the bathymetric data (top) and SSS record (bottom) Images centred on E; N (6x Exaggeration for bathymetry). SSS record from line DBA10KJM136201A. GEMS International Group of Companies 45

55 Figure 36 Wreck (ID 1002) identified in the bathymetric data (top) and SSS record (bottom) Images centred on E; N (6x Exaggeration for bathymetry). SSS record from line DBA10KJM158101C. GEMS International Group of Companies 46

56 6. SUB-BOTTOM GEOLOGY A geological schematic of the GEMS delineated sub-seabed units is as follows; Figure 37 Geological schematic of Interpreted Sub-seabed Geology in Tranche A. This model was used during acquisition and processing, with final interpretation submitted to Forewind on 23 rd September It is understood that with the input of the British Geological Society (BGS) that this model has since been reviewed. BGS acknowledge that deviations occur from the published map sheets which were used to formulate this initial model. BGS confirm that the 1:250,000 maps cannot be used exclusively for high resolution surveys, Dave Long (18/11/2011). 6 horizons (A through G) were identified across the Tranche A site by GEMS, which signify distinct variation in seismic character. These horizons bound Units a through g, where Horizon A marks the base of Unit a. GEMS International Group of Companies 47

57 The following table summarises the main geological units identified across the Tranche A site. Table 10 Observed Depths of Geological Units Horizon ID Interpreted Geological Formation Unit ID Horizon Depth (m) A Holocene Channel Infill a <1-10 Holocene Sediments b B <1-15 Dogger Bank Formation / Twente Formation c (overlain by b / ci ( ci assumed to be the Dogger Bank Volans Member)) C Cleaver Bank Formation / Egmond Ground Formation d D Swarte Bank Formation e E Yarmouth Roads Formation f (overlain by d / e ) F Aurora Formation g (overlain by e / f ) G 41->350 The GEMS interpretation has focussed on these main lithographic units critical to defining the geotechnical attributes of the sub-bottom geology. These units are discussed in the following sub sections. The profiles which follow are displayed in time below seabed, where 10ms can be assumed to represent 8m for near seabed depth approximations. Shot points are 5m apart, therefore 100 shots represent 500m. GEMS International Group of Companies 48

58 6.1 Unit a The base of Unit a (Horizon A), is a strong reflector close to the seabed and could be interpreted as the Botney Cut Formation. Unit a reaches a maximum depth of 10m BSB. Unit a is more evident to the west of the region and its occurrence reducing the intensity of the underlying Horizon B (Figure 38). West East Unit a Seabed Unit b 10ms (c. 8m) Unit c Figure 38 Shallow sub-bottom profile showing Unit a overlying Unit b. Line DBA10AQM1087, centred on E, N 6.2 Unit b The base of Unit b (Horizon B), assumed to be the top of the Dogger Bank Formation, is defined by a moderate to strong horizon, where it is nears the seafloor (less than 1m), and comprises Holocene sediments. The base of the unit reaches a maximum depth of 33m (Zone A). The internal characteristics of Unit b are variable with depth and generalised as acoustically transparent. In deeper sections there are sub-parallel reflectors indicative of channel infill (Zone A east). Horizon B can be observed as the erosional base of the sandwaves observed on the seabed and can be seen to terminate at the seabed where sandwaves are not present (Figure 39). West East Seabed Unit b 10ms (c. 8m) Unit c Figure 39 Shallow sub-bottom profile showing the sand waves with exposed Horizon B. Line DBA10AQM1121, centred on E, N. Figure 40 shows the isopach of Horizon B. It is understood from recent client feedback, received from Forewind on 18/01/2012 that this horizon may form the base of the Bligh Bank Formation. The depth of the horizon in the centre of Zone A is beyond the penetration of the pinger and can be seen as a very shallow horizon in the Sparker data (Figure 46). Unit b also shows thickening associated with channel infill. GEMS International Group of Companies 49

59 Horizon B not present Horizon B exposed at surface Horizon B main lines not interpretable Figure 40 Base of Unit b (depth in metres bsb) GEMS International Group of Companies 50

60 6.3 Unit c The base of Unit c (Horizon C), assumed to be the Dogger Bank Formation, is defined by a characteristically strong but discontinuous reflector. The base of the unit is generally found between 25m and 40m BSB but does reach depths of 60m in some parts of the site, and may be present at 16m below the surface, or eroded away completely where localised faulting is interpreted to have occurred (Figure 41). Southwest Northeast 50ms (c. 40m) Figure 41 Thinning of Unit c in localised area of faulting; Line DBA10AQM111401A, centred on E, N. The depth below seabed of Horizon C is illustrated in Figure 43. Shallow channels are occasionally observed cutting through the top of the unit across the site, the base of which has been defined as Horizon Ci (internal). This is thought to be evidence of the Volans Member of the Dogger Bank Formation. Unit c is observed across most of the Tranche A site, however it appears to be absent in the extreme west of the site. GEMS International Group of Companies 51

61 The internal characteristics of Unit c are found to be highly variable across the site although there is a general tendency towards acoustically transparent or chaotic characteristics (Figure 42). In areas toward the north and east of the site however, sub-parallel reflectors are common. Shallow internal channels are found across the site within the Dogger Bank Formation. Infill of many of these channels is acoustically transparent although sub-parallel reflectors are observed within some of the channels. In the southern and western areas of the site, strong internal reflectors are observed close to the base of the formation, thought to be evidence of gravel beds. West East Seabed Unit b 10ms (c. 8m) Acoustically Transparent Unit c Chaotic Internal Structure Figure 42 Acoustically transparent and chaotic internal structure of Unit c Line DBA10AQM123901A, centred on E, N. Horizon C is typically sub-horizontal, though this characteristic is not true across the whole site. Horizon C deepens towards the centre of the site, and a shallowing is observed in the east and west of the site (Figure 43) to an interpreted minimum of 16m. In these areas Horizon C is not interpretable. The region appears to be characterised by a series of interconnected channels of deltaic structure between 40m and 60m below the seabed. At the western limit of Horizon C near surface faulting can also be observed throughout Unit c which makes interpretation too difficult without geotechnical input. It is to be noted that Horizon C was believed to form the base of the Dogger Bank Formation, however feedback received from the British Geological Society via Forewind on 18/01/2012 explains the complexity of mapping Horizon C. It is apparent that when not clearly evident in the record the GEMS interpretation has mapped the underlying top of the Egmond Ground Formation. In these instances the Cleaver Bank Formation can be observed overlying the Egmond Ground Formation, and it is in fact the base of the Cleaver Bank Formation which has been mapped in these instances. The difficulty arises from the GEMS interpretation of Unit d which represents both the Cleaver Bank and Egmond Ground Formations. Further feedback received from Forewind indicates that the lack of sub seabed boulders identified by the survey and the results from the follow up geotechnical works has led to a change in the interpreted geological setting of Unit c, from having a mainly glacial marine depositional environment to that of a glacial lacustrine, pro-glacial water laid deposit. For instances where Unit c is observed at the seabed, the seabed features charts have been changed for this revision to reflect the change in geological understanding, with all reference to boulder clay changing to stiff clay with associated cobbles and boulders. GEMS International Group of Companies 52

62 Horizon C not interpretable Horizon C not interpretable Horizon C not interpretable Figure 43 Base of Unit c (depth in metres bsb) GEMS International Group of Companies 53

63 6.4 Unit d Unit c and Unit e / Unit f are separated by the relatively thin Unit d, which is characterised by its acoustically chaotic nature. The basal reflector is relatively weak and uneven across the site, and consequently the horizon has not been mapped fully. The basal reflector was also observed to have significant changes in amplitude across the site, with the most significant increases coincident with truncation of the underlying channel infill. It is believed that the unit is a combination of the Egmond Ground Formation and the Cleaver Bank Formation. Although Unit d is generally chaotic in character, in some places sub-parallel reflectors can be observed. Units d and c are acoustically and geologically very similar, making it difficult to delineate the boundary between the two in some areas of the site, as evident in Figure 46. The basal reflector of the unit (Horizon D) was observed to change depth across Tranche A fairly rapidly; hence the thickness of the unit is variable across the site. 6.5 Unit e Horizon E marks the base of Unit e, which is assumed to be the Swarte Bank Formation, a unit of scaphiform infill channels, cut into the underlying Unit f. This unit is present as a single, complex channel system running East-West across the site. The horizon generally lies between 50m and 210m BSB. The unit generally comprises two or more channelling phases, of which the earliest, deepest phase has been represented as Horizon E. The infill between the two main phases of channelling has differing acoustic characteristics. The primary phase of channelling infill tends to be more acoustically transparent, while the later phases appear to consist of sub-parallel internal reflectors. Additionally, the primary phase is typically characterised by a v-shaped asymmetric form, compared to the more rounded, symmetrical profile found in the later phase. The channel system features several major tributaries joining into a single central flow direction towards the west of the site. In the east of the site adjacent to the main-channel system a shallow, broad channel system has been observed with distinct sub-parallel reflectors (Figure 44). It is not clear as to whether this is linked with the larger deeper channel complex. GEMS International Group of Companies 54

64 Figure 44 Spatial illustration of depth BSB (m) to Horizon E, the base of Unit e 6.6 Unit f Unit f, which is thought to represent the Yarmouth Roads Formation, has been identified in all areas of the site, although the upper- and lower-most limits of the unit are both observed to be discontinuous uninterpretable on occasion. Between Horizon D/E and Horizon F, the unit was found to have a basal surface between 100m and 200m below seabed. The unit appears to thicken towards the east of the site, from around 50m BSB in the west, to approximately 130m BSB in the east. Unit f was observed to be chaotic through most of the site however there are some areas of sub-parallel reflections. There appears to one prominent internal reflector within the unit, with numerous other discontinuous reflectors. The formation is incised by the large channel system defined as Unit e (previous section). 6.7 Unit g Unit g, which is assumed to represent the Aurora Formation, is the earliest identified quaternary unit in Tranche A. The unit is overlain by Unit f and overlies a geological unconformity. The unit is typically observed at a depth of 100m to 200m BSB, deepening in an easterly direction. Horizon G is a geological unconformity, which is defined as the base of the unit. This horizon is seen to shallow significantly to the northwest of the site. Unit g is characterised internally by widespread sub-parallel reflectors, although in some places the unit can be chaotic. The Horizon G is relatively weak and is often not present. The horizon is frequently incised by initial phases of channelling associated with Unit e (Figure 45). Towards the East of the site the complex faulting which has occurred above has disturbed Unit g and this area has been highlighted in Figure 45. GEMS International Group of Companies 55

65 Figure 45 Spatial illustration of depth BSB (m) to Horizon F, the base of Unit f. The red polygon depicts the area disturbed by faulting GEMS International Group of Companies 56

66 Figure 46 summarises the units identified across the Tranche A site. The characteristics shown are representative to those experienced across the site. 50ms (c. 40m) Figure 46 Representative sparker interpreted profile Line DBA10AQM147501A, centred on E, N. GEMS International Group of Companies 57

67 7. GEOPHYSICAL AND HYDROGRAPHIC INTERPRETATION 7.1 Overview The Tranche A survey area has been split into zones of similarity using the seabed features interpretation and the bathymetry. The seabed sediment type has been interpreted from the side scan sonar mosaic record with observations of the acoustic intensity and characteristics. Although a desktop study was carried out, no ground-truthing was performed as part of the survey. The following four seabed features zones have been identified; Zone A - Benign seabed of predominantly SAND with gravel patches and abundant megaripples and sandwaves. Zone B - Predominantly SAND with some gravel, stiff clay (with associated cobbles and surface boulders) and mixed sediment with some sandwaves. Zone C - Predominantly SAND with some gravel and mixed sediment with areas of sandwaves. Zone D Chaotic outcrops of stiff clay (with associated cobbles and surface boulders), gravel and mixed sediment. Figure 47 shows the delineation of these areas within the Tranche A survey bounds. Figure 47 Overall Spatial Representation of Sediment Types in Tranche A A full description of these zones has been compiled in the following sections. GEMS International Group of Companies 58

68 7.2 Slopes Slopes across the site have been analysed with reference to Table 11 and are presented in Figure 48 Table 11 Slope Categories % Slope Range Slope Range Descriptor 0% to 5% 0 to 2.9 slightly 6% to 10% 3 to 5.9 gently 11% to 15% 6 to 8.9 moderately 16% to 20% 9 to 11.9 steeply 20% 12 very steeply or extremely There are no slopes in Tranche A that can be defined as greater than gently sloping. The majority of the site can be classified as slightly sloping, with slopes ranging from 0 to 2%. However, in areas of sandwaves and in the valleys, localised gentle slopes have been identified and there are potentially small isolated slopes associated with sediment transportation, in particular the lee slopes of sandwaves in all Zones. Slope values were calculated using DMagic on a 10m grid. The slope surface is computed so that it represents the maximum slope from each cell to any of its neighbouring cells. Slope values are displayed in decimal degrees. GEMS International Group of Companies 59

69 Figure 48 below is a slope shaded image that has been draped over the bathymetry DTM. It illustrates the variation in slope throughout the site, highlighting the areas in Zones B, C and D as well as the localised sandwaves and valleys within Zone A as being irregular and rough in texture. Zone C Zone B Zone D Zone A Zone C B-B Zone D Figure 48 Site slope values (degrees from horizontal) which highlights the valley locations There are no significant depressions throughout the site however a number of valleys can be observed striking predominantly Zones C and D with depths of approximately 3m and residing in water depths of 23-26m. The observed valleys cover approximately 50% of the site with the only significant area of clear relief being in Zone A to the East. Figure 49 shows the profile character of the valleys labelled in Figure 48, where a rough seabed texture and irregular bathymetry is evident. These valleys are found in the geophysical datasets to be coincident with outcrops of underlying stiff clay material. GEMS International Group of Companies 60

70 Figure 49 Valley profile B-B (as indicated in Figure 48) Centred on E, N. GEMS International Group of Companies 61

71 7.3 Near Surface Geological Discussion The sub bottom geology clearly interacts with the seabed and affects the seabed features observed. Figure 50 and Figure 51 illustrates how the surface of Unit c, as identified in the sub-bottom data, and the water depth as analysed from the bathymetric data respectively, show significant trends in relation to the zones introduced in Section 7.1. Here Tranche A is split into similarity Zones (A through D). Zone D, defined as being characterised by chaotic outcrops of stiff clay, gravel and mixed sediment, coincides with a large area where Unit c (which comprises of stiff clay sediment) beneath the surficial sediments appears to sub- or outcrop at the seabed. Overall these occurrences correspond with greater water depths than the surrounding areas and the valley bottoms, as described in the Bathymetry Section 4 of this report. Horizon B main lines not interpretable Figure 50 Shaded colour depth BSB to Horizon B, interpreted to mark the surface of Unit c The relatively benign seabed of Zone A coincides with deeper occurrences of Unit c and a largely flat, featureless seabed observed in the bathymetry (Figure 51). This contrasts with sub- or outcrop of Unit c across Zone D where the nature of the seabed bathymetry is undulating. GEMS International Group of Companies 62

72 Figure 51 Colour banded illustration of bathymetry across Tranche A A breakdown of each of the zones and their individual characteristics follows; Zone A Zone A can be found in the East of Tranche A (Figure 52) and characterises 38% of the survey area at approximately 740km². The seabed is relatively benign and of low acoustic reflectivity, interpreted to indicate a sand seabed, with less than 1% of the area representing high reflectivity sediments. These acoustically high reflectivity sediments are characterised by a considerable presence of high relief boulders, and are thought to represent small outcrops of the underlying Unit c as described previously. Unit c is interpreted to represent the widespread Dogger Bank Formation however this does not dominate the seabed features in this zone. GEMS International Group of Companies 63

73 Figure 52 Zone A as defined from Seabed Features Interpretation Towards the centre of Zone A, covering approximately 65km² is a concentration of medium reflectivity interpreted to be gravel patches amongst the SAND. These gravels are likely to comprise gravel grade shell fragments. Within this concentration, megaripples can clearly be observed in the sonar record as predominantly sub-metre scale variations / linear concentrations of gravel. The crest orientation indicates an overall NNW to SSE flow regime. Central, northwestern and southeastern areas of Zone A exhibit significant localised depressions in the interpreted Horizon B (uppermost bound of Unit c ). In the southernmost part of the zone, there appears to be linear valleys with amplitudes of up to 10m (Figure 50). There are several predominantly North-South orientated seabed valleys evident in both sub-bottom and bathymetric datasets, where coarse sediment (GRAVEL) is identified at the seabed in the base of the valleys. An internal channel is observed within the interpreted Unit c, the infill of which has been defined as Unit ci and is thought to represent the Volans Member of the Dogger Bank Formation as illustrated in the following pinger profiles. Infilled channels, identified as Botney Cut Formation, are also observed near the surface within Zone A. Southwest Northeast ~ 500m 10ms (c. 8m) Seabed Seabed Valley Unit B Unit C Figure 53 Pinger SBP profile of Unit b overlying Unit c with evident seabed valleys GEMS International Group of Companies 64

74 Southwest Line DBA10KJM136701A, centred on E, N. Northeast ~ 500m Unit B Seabed 20ms (c. 16m) Unit Ci Unit C Unit C Figure 54 Pinger SBP profile of sub-cropping/outcropping Unit c with incised Unit ci Line DBA10KJM116701A, Centred on E, N. Few sporadic sonar contacts are observed in this zone with many of these attributed to minor geological depressions. Several magnetic anomalies are observed in this zone with the majority associated with the East-West running UK-Germany 6 cable and the remainder likely to be associated with minor debris or sub surface geology. The bathymetry in the rest of the area is predominately flat ranging 20m-30m with some shallow valleys to the Southeast approximately 2m deep. Figure 55 Bathymetric image of observed bedforms. Centred on E, N with vertical exaggeration of six times. GEMS International Group of Companies 65

75 7.3.2 Zone B Zone B can be found in the North of Tranche A and characterises 20% of the survey area at approximately 380km² (Figure 56). The seabed is a relatively complex mixture of varying acoustic return. High relief boulders can be observed at the seabed in areas of localised high acoustic reflectivity, interpreted to be outcrops of the defined Unit c. These occasional outcrops of stiff clay (with cobbles and boulders of varying frequency) can be observed in thin (<500m) ribbons orientated NNW to SSE, and make up approximately 20% of the Zone B area. These outcrops are also evident in the sub-bottom profiler record (Figure 50). The outcrops identified in the side scan sonar record may be smaller in area than those identified in the sub-bottom profiler record due to a veneer of finer sediment (Unit a / b ) overlying Unit c. The majority of these outcrops are less than 1km². The sediment type adjacent to these stiff clay ribbons is often interpreted as sandy gravel or gravel of medium reflectivity. This gravel often provides a gradational change from the high relief stiff clay and surrounding benign sand seabed of low acoustic reflectivity, which remains the predominant seabed type of Zone B covering approximately 300km². Surficial sediments have an average thickness throughout Zone B of approximately 2m. Figure 56 Zone B as defined from the Seabed Features Interpretation Megaripples can be observed in the interpreted gravel, but they are not as dominant as those observed in Zone A and often cover isolated areas of <1km². The megaripples are of a wavelength of predominantly 1-2.5m and the crest orientation indicates a NNW to SSE flow regime. The bathymetry in this area shows valleys in the southwest of the zone that are approximately 3m deep which has been interpreted as outcrops of the defined Unit c, where stiff clay is exposed at the seabed in the base of the valleys. An example of the valley topography with the gravel boundary overlain is illustrated in the following figure; GEMS International Group of Companies 66

76 N Figure 57 Shaded colour bathymetry with delineated gravel boundary located within a valley Centred on E, N with vertical exaggeration of thirty times. Sandwaves are present only in 20% of the zone, mainly in the shallow areas, and can be observed in the following sub-bottom profile where there is also evidence of Unit c exposure within a topographic low. Southwest Northeast ~ 500m Unit B Seabed 10ms (c. 8m) Unit C Figure 58 Sub-bottom profile showing sandwaves overlaying Unit c and seabed valleys coincident with outcrops of Unit c Line DBA10KJM120502A, centred on E, N. GEMS International Group of Companies 67

77 7.3.3 Zone C Zone C can be found along the Southwest boundary of Tranche A and characterises 18% of the survey area at approximately 340km² (Figure 59). The seabed within this zone has very similar characteristics to Zone B, which is also adjacent to Zone D. However there is little evidence for high relief boulders and seabed characteristics which are clearly indicative of stiff clay. Where boulders do occur they reside in areas of mixed sediments. The interpreted mixed and gravel areas observed are often thin (<500m) ribbons orientated NNW to SSE, stretching 1-3km, as in Zone B. The majority of these outcrops are less than 1km² and are surrounded by low relief benign sand seabed of low acoustic reflectivity, which remains the predominant seabed type, covering approximately 280km² of Zone C. The underlying Unit c is generally identified at between 0.5m and 3m BSB, deepening towards the centre of Zone C. Zone C Figure 59 Zone C as defined from Seabed Features Interpretation Megaripples are again observed in the medium relief interpreted gravel sediments, with the same dominant NNW to SSE flow regime. The megaripples observed here are of variable wavelength. GEMS International Group of Companies 68

78 The bathymetry in Zone C is similar to that of Zone B; valleys are observed in the southeast of the area, that are approximately 4m deep, where gravel can be observed to reside. Water depths range from 20m-30m. N Figure 60 Shaded colour bathymetry with delineated gravel boundary located within valley Centred on E, N with vertical exaggeration of thirty times. Sandwaves are only present in 10% of the Zone. The sandwaves to the north east of the zone are along the western flank of a ridge in approximately 20m water depth. There is little exposure of Unit c within Zone C, as evident by the lack of high reflectivity sediment in the side scan sonar record and a prominent layer of surficial sediments exhibited in the sub-bottom profiler record. Sediments overlying the interpreted Unit c appear to deepen significantly as shown in the pinger sub-bottom profile of Figure 61. Southwest Northeast ~ 500m Seabed Unit b 10ms (c. 8m) Unit c Figure 61 Shallow SBP profile showing surface geology within Zone C as found to the north Line DBA10AQM111401A, centred on E, N. Further south in Zone C, the interpreted Unit c typically is observed at less than 7m BSB, occasionally outcropping (Figure 62 and Figure 63). The extent of exposure of the underlying unit through the surficial low reflectivity sediments is approximately 10% in the southernmost area of Zone C. Other features of note observed within the sub-bottom record include North-South orientated valleys where underlying sediment is exposed. Southwest Northeast ~ 500m GEMS International Group of Companies 69

79 Seabed Unit b 10ms (c. 8m) Unit c Figure 62 Shallow SBP profile showing surface geology within Zone C as found in the west Line DBA10KJM123601A, centred on E, N. Southwest Northeast ~ 500m Seabed 10ms (c. 8m) Unit c Unit b Figure 63 Shallow SBP profile showing surface geology within Zone C as found in the southwest Line DBA10KJM153501A, centred on E, N GEMS International Group of Companies 70

80 7.3.4 Zone D Zone D can be found in a NW to SE orientated band which stretches across the entire length of the Tranche A area, comprising 24% of the survey area, equating to approximately 430km² (Figure 64, Figure 65 and Figure 66). The seabed here is distinctly different than the adjacent zones; sand is no longer the predominant sediment type observed, while approximately 75% of the seabed within the zone comprises outcropping harder material of Unit c. Where there is a presence of surficial sand overlying Unit c, its thickness is typically between 3m and 7m, however this thins towards the northernmost section of Zone D. The acoustic intensity and character across this zone is highly variable, where stiff clay, gravel and mixed seabed types dominate the seabed equally, adjacent to one another in ribbons which are often orientated NNW to SSE. Cyclical variations in these thin (<500m) ribbons can be observed to the South of this zone where sediment interpretation changes frequently, from gravel to stiff clay and back, but also from stiff clay to gravel to Mixed and back. This cyclical behaviour is clearest in Figure 64. Figure 64 Zone D as defined from Seabed Features Interpretation (South) Megaripples can be observed in all of these major sediment types, again orientated with a flow regime of NNW to SSE and of variable wavelength. There are few sporadic sonar contacts observed to the south of this zone but several towards the north. The majority of these can be attributed to large isolated boulders predominantly in the mixed classification. Variations in sediment classification in the north and centre of Zone D are no longer cyclical as in the south of the zone, but appear more random and not in the ribbon forms observed elsewhere. Mixed sediment classification dominates the record in the centre of the area where the acoustic character is most chaotic. GEMS International Group of Companies 71

81 Figure 65 Zone D as defined from Seabed Features Interpretation (West) The largest interpreted outcrop of stiff clay is observed north of the centre of Zone D; covering an area of approximately 6.5km², orientated North-South (Figure 65). This is consistent with the exposure of Unit c observed in the pinger sub-bottom profiler record (Figure 50; Figure 68). At the northernmost extent of Zone D, sediment classifications show fewer noticeable trends, although the NNW to SSE orientation of a given sediment type can still be observed. The complicated character of the seabed here is attributed to the chaotic nature of Unit c which outcrops frequently in this area and is also understood to be reworked by seabed currents. GEMS International Group of Companies 72

82 Figure 66 Zone D as defined from Seabed Features Interpretation (North) Bathymetry in Zone D is at its deepest ranging from 35m-40m and shows large areas of Unit c outcropping at the seabed. There are no sandwaves identified in this zone. N Figure 67 Shaded colour bathymetry with the delineated Unit c exposure boundary coincident with a topographic valley Centred on E, N with vertical exaggeration times thirty. GEMS International Group of Companies 73

83 Southwest Northeast ~ 500m 10ms (c. 8m) Seabed Unit b Unit c Figure 68 Shallow sub-bottom profile showing the sub- outcrop of Unit c Line DBA10KJM132601A, centred on E, N. Southwest Northeast ~ 500m 10ms (c. 8m) Seabed Unit b Unit c Figure 69 Shallow SBP profile showing sub-outcrop of Unit c and correlation with valley topography Line DBA10KJM153501A, centred on E, N 7.4 Sediment Sampling and In-Situ Testing No sediment sampling was performed during survey operations, thus the seabed sediment type has been interpreted purely from the SSS mosaic record with observations of the acoustic intensity and characteristics. A desktop study of the region and the British Geological Society charts were used as an aid to interpretations. Client feedback received on 18/02/2012 indicates that the seabed features interpretation and the camera work correlate well. GEMS International Group of Companies 74

84 8. POTENTIAL HAZARDS 8.1 Shallow Gas There are numerous small areas of high amplitude anomalies, interpreted as potential pockets of shallow gas, throughout the site. The majority of these high amplitude anomalies are isolated although a broad scale area is observed to the Southeast of the site (Figure 71) and the isolated occurrences do appear to form a North-South linear trend across site centre. These areas have been identified due to the presence of high amplitude reflections immediately overlying an instance of acoustic blanking or where coherent signal is reduced and significant reverberation is evident. The broad scale region is considered to be widespread diffuse gas and is shown in Figure 70. Southwest Northeast ~ 500m Seabed 100ms Reverberation / Acoustic Blanking Figure 70 Profile showing apparent reverberation and acoustic blanking associated with gas presence Line DBA10KJM159501A, centred on E, N. GEMS International Group of Companies 75

85 Figure 71 Spatial illustration of the high amplitude anomalies observed across the site GEMS International Group of Companies 76

86 8.2 Potential Peats Peat and shallow gas exhibit similar qualities in the sub-bottom profile data, thus the appearances of shallow gas in the areas described in Section 8.1 may indicate a presence of shallow buried peat. Another example of a high amplitude anomaly is presented in Figure 72 which may be explained by a possible near seabed peat layer (as indicated). Southwest Northeast High Amplitude Anomaly Possible Peat Layer Multiples Acoustic Blanking 100ms Figure 72 High amplitude anomalies present Line DBA10KJM153501A, centred on E, N. GEMS International Group of Companies 77

87 8.3 Faults Significant evidence of faulting is interpreted within the uppermost 100m of the sub-bottom record at the Northwest of the site (as illustrated in section 6.4 unit f ). The faulting has been interpreted due to the complexity of the substrate within the top 100m, which is locally characterised by significant vertical offsets and folding as shown in the previous Figure 41. Further study needs to be carried out to investigate the complex fault structures and their timings, observed here. There have been no instances of lithified sediments identified at the seabed within the survey area. 8.4 Small Bodies of Sand Small bodies of sand can be observed amongst areas of differing classification (e.g. mixed or boulder clay ). These localise metre scale bodies could provide differing conditions to the generalised sediment type depicted in the charts. Isolated sands / sediment patches may be a function of the erosion/attrition of cobbles and boulders exposed at the seabed. GEMS International Group of Companies 78

88 8.5 Channels / Soft Channel Infill The area has been heavily channelized in numerous phases throughout the site. Shallow channels within the uppermost layer of surficial sediments are evident and the majority are likely to comprise of similar sediments to the surrounding material. Compaction rates of the channel infill may differ, however the similarity of the sediment type and its generally course calibre would suggest that these instances do not pose a threat to operations. Feedback received from Forewind on 18/01/2012 indicates that as the understanding of the geology has developed, post-acquisition, occurrences of the Botney Cut Formation have been identified. These are observed as soft clay infilled channels which often reside within pre-existing sand filled channels. These instances would be significant for engineering purposes. Channels are also observed towards the top of Unit c. Infill of these channel features has been described as Unit ci (internal) and is interpreted to represent the Volans Member of the Dogger Bank Formation. The most significant channels are those interpreted as Unit e, the interpreted Swarte Bank Formation. This unit is incised into the underlying Unit f over widespread linear areas across Tranche A (as section 6.4 Unit e ). The steep sided nature of these channel forms will result in distinct lateral variations in installation and geotechnical properties. 8.6 Cobbles / Boulders Cobbles and boulders are observed when stiff clay is observed at the seabed. The largest accumulation of stiff clay is within Zone D, where sediment cover is lacking and the underlying substrate is exposed. Zone D, as described in Section 6, which is present in a NW-SE orientation across the entire western flank of the survey area, is characterised by numerous outcrops of this substrate, interpreted as stiff clay with cobbles and boulders. This area, as well as large areas at the southern and northern ends of the site (mainly within Zone C), also feature widespread thin sediment cover, where the clay is present just beneath the seabed. Boulders are not evident in the sub bottom record beyond the seabed. Feedback received from Forewind on 18/01/2012 indicates that this has led to a change in the geological setting of Unit c, the interpreted Dogger Bank Formation, from having a mainly glacio-marine depositional environment to that of a glaciolacustrine, pro-glacial water laid deposit. It is however still possible that sub seabed boulders exist within Unit c undetected in the sub-bottom record, and may therefore pose a risk to installation. No such instances have been encountered when completing the recent geotechnical works. 8.7 Surface Obstructions Three cables and one pipeline can be observed in the Tranche A survey area. These linear features can be observed most prominently in the magnetometer record although also observed in the pinger and side scan sonar record when at the seabed. Section 5.3 Existing infrastructure and section 5.4 Contacts goes into more detail about existing infrastructure seabed hazards (including well heads and wrecks). Of note fishing activity may also pose a threat to future operations particular in shallow areas where long line pot fishing may be favourable. Post survey fishing debris must also be considered as the Dogger Bank forms a popular fishing ground with shallow waters forming nurseries for fish populations. Sediment transportation (Section 5.2) may also provide surface obstructions and these forms are likely to have relocated / changed in form, post survey. Erosion of superficial sediments may also reveal further obstructions beneath. GEMS International Group of Companies 79

89 GEMS International Group of Companies Geotechnical, Geophysical and Metocean Expertise around the World APPENDIX A SEABED FEATURES TARGET DATABASE GEMS Survey Limited St. James House, St. James Place, Gains Lane Devizes, Wiltshire, SN10 1FB United Kingdom Registration Number: T: F: [email protected]

90 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 ID Average E Average N Length (m) Width (m) Height Azimuth (Depth) (deg.) Class Type Comment Associations DBA_S Point Contact Wreck DBA_M6221 (60m), W40002 (58m), M10069 (100m) DBA_S Point Contact Wreck DBA_M6130 (45m), DBA_M6131 (84m) DBA_S Point Contact Wreck DBA_M6043 (20m), DBA_M6047 (64m), W40001 (27m) DBA_S nmd 99.2 Linear Contact Scar (Trawl or Anchor) DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S nmd 84.1 Linear Contact Scar (Trawl or Anchor) DBA_S nmd 87.0 Linear Contact Scar (Trawl or Anchor) DBA_M6022 (57m) DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20007 (32m) DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_M6007 (32m) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Linear Contact Linear Debris Possible buried object or sediment disturbance DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression Page 1 of 40

91 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S nmd Geological Depression DBA_S nmd Geological Depression DBA_S nmd Geological Area of Depressions DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S nmd Geological Area of Depressions DBA_S nmh Point Contact Unit Debris DBA_S nmd Geological Depression DBA_S nmh Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Area of Depressions DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Double shadow on target DBA_S Geological Boulder B20009 (8m) DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Area of Depressions DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Geological Boulder DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S nmd Geological Depression DBA_S Point Contact Unit Debris Page 2 of 40

92 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Depression DBA_S nmd Geological Depression DBA_S nmd Geological Depression DBA_S Geological Depression DBA_S nmd Geological Depression DBA_S Geological Depression DBA_S nmh Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Linear Contact Linear Debris DBA_M5102 (19m) DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S nmd Geological Depression DBA_S Geological Boulder DBA_S nmh Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S nmh Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S nmh 96.0 Point Contact Unit Debris DBA_S nmh 66.1 Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S nmd Geological Depression DBA_S nmh 68.2 Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S nmh Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Page 3 of 40

93 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S nmh Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S nmw nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmh Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S nmd 90.7 Linear Contact Scar (Trawl or Anchor) DBA_S nmh Environmental Fish Return from fish shoal DBA_S Linear Contact Linear Debris DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Linear Contact Scar (Trawl or Anchor) DBA_S nmd Geological Depression DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Page 4 of 40

94 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster Page 5 of 40

95 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Geological Boulder Cluster DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Boulder Cluster DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 6 of 40

96 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris B20018 (6m) DBA_S Geological Boulder B20019 (2m) DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_M6136 (41m) DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_M6138 (9m) DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 7 of 40

97 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 8 of 40

98 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Linear Contact Linear Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 9 of 40

99 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder B20021 (6m) DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 10 of 40

100 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Cluster Contact Unit Debris 3 small items, maximum DBA_S1594 dimension (60m) 2x2x2m, possibly associated with 1594 DBA_S Point Contact Unit Debris DBA_S Cluster Contact Unit Debris 3 small items, possible DBA_S1592 associated with (60m) 1592 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 11 of 40

101 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Area of Depressions DBA_S Geological Area of Depressions DBA_S Geological Boulder Cluster DBA_S Geological Depression DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris With scouring around base DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20030 (9m) DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 12 of 40

102 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S nmh Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Scar (Trawl or Anchor) DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20041 (11m) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20056 (5m) DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20072 (5m) DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 13 of 40

103 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd 94.0 Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Depression DBA_S Geological Boulder DBA_S Linear Contact Linear Debris DBA_S Geological Depression DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder B20148 (4m) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Area of Depressions DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmh Linear Contact Linear Debris DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S Point Contact Unit Debris DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) Page 14 of 40

104 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S nmh Linear Contact Linear Debris Associated with 1752 DBA_S1752 (71m) DBA_S nmh Linear Contact Linear Debris Associated with 1751 DBA_S1751 (71m) DBA_S Geological Depression DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Area of Depressions DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Area of Depressions DBA_S Geological Boulder DBA_S Geological Area of Depressions DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% Page 15 of 40

105 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Linear Contact Linear Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Area of Depressions DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% Page 16 of 40

106 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20036 (18m) DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster Page 17 of 40

107 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 18 of 40

108 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% Page 19 of 40

109 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20047 (11m) DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Linear Contact Linear Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 20 of 40

110 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20053 (36m) DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20068 (15m) DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Depression DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 21 of 40

111 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder B20034 (3m) DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% Page 22 of 40

112 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris Possible Debris from Small Wreck DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Cluster Contact Unit and Linear Debris Cluster of various objects DBA_M6244 (45m) DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Page 23 of 40

113 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% Page 24 of 40

114 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris Page 25 of 40

115 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20051 (5m) DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 26 of 40

116 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster Page 27 of 40

117 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder B20077 (4m) DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris Page 28 of 40

118 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Depression DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder Page 29 of 40

119 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder Page 30 of 40

120 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Page 31 of 40

121 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% Page 32 of 40

122 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Point Contact Unit Debris DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Linear Contact Linear Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder Page 33 of 40

123 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S nmh Linear Contact Linear Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Isolated Rock <5% DBA_S Geological Isolated Rock <5% DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder Page 34 of 40

124 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Page 35 of 40

125 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder B20099 (33m) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Linear Contact Wire Rope or cable partially dug into seabed DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Page 36 of 40

126 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_M5011 (29m) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder M10079 (25m) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Page 37 of 40

127 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder M10080 (9m) DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S nmw nmd 52.3 Linear Contact Scar (Trawl or Anchor) DBA_S nmw nmh 42.5 Linear Contact Wire Rope or cable, associated DBA_S3081 with (132m) DBA_S nmw nmh 73.8 Linear Contact Wire Rope or cable, associated DBA_S3080 with (132m) DBA_S nmw nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmw nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmw nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmw nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmw nmd 20.8 Linear Contact Scar (Trawl or Anchor) DBA_S nmw nmd Linear Contact Scar (Trawl or Anchor) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder Page 38 of 40

128 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Depression DBA_S Geological Boulder Cluster DBA_S Geological Boulder B20128 (11m) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S nmw nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd Linear Contact Scar (Trawl or Anchor) DBA_S nmd 16.0 Linear Contact Scar (Trawl or Anchor) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S nmw nmd 88.2 Linear Contact Scar (Trawl or Anchor) DBA_S Geological Boulder B20071 (4m) DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Linear Contact Scar (Trawl or Anchor) DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S nmw nmd 32.9 Linear Contact Scar (Trawl or Anchor) DBA_S Geological Boulder Page 39 of 40

129 Project: Dogger Bank Tranche A Target Database Contract No.: GSL10109 DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Linear Contact Linear Debris DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Point Contact Unit Debris DBA_S Geological Boulder DBA_S Geological Boulder Cluster DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Boulder DBA_S Geological Depression DBA_S Geological Boulder Page 40 of 40

130 GEMS International Group of Companies Geotechnical, Geophysical and Metocean Expertise around the World APPENDIX B FIGURE BASE MAP GEMS Survey Limited St. James House, St. James Place, Gains Lane Devizes, Wiltshire, SN10 1FB United Kingdom Registration Number: T: F: [email protected]

131 400000E E E N N DBA10AQM104201A DBA10AQM1087 DBA10AQM111401A DBA10AQM1121 DBA10KJM118501A DBA10KJM123601A DBA10KJM123901A DBA10AQM104201A DBA10KJM116701A DBA10KJM136201A DBA10AQM DBA10KJM136701A DBA10AQM140901A DBA10AQM111401A 42 DBA10AQM DBA10AQM1454 DBA10AQM145701B DBA10AQM145701A DBA10AQM1480 DBA10KJM116701A DBA10AQM1536 DBA10KJM118501A DBA10KJM120502A DBA10KJM120502A 58 DBA10KJM155501A DBA10KJM123601A DBA10KJM123901A DBA10AQM145701B DBA10KJM132601A DBA10KJM132601A DBA10AQM DBA10AQM147501A DBA10KJM153501A DBA10KJM136201A DBA10KJM136701A DBA10AQM140901A DBA10AQM1454 DBA10AQM145701A DBA10AQM DBA10AQM1536 DBA10KJM155501A DBA10KJM158101C DBA10KJM158101C DBA10KJM159501A DBA10AQM DBA10AQM147501A LEGEND 70 DBA10KJM153501A DBA10KJM159501A 67 Survey Limit Track L ine DBA10KJM155501A Track Line Name Extent of sub bottom data 21 Location of figure in report N N N E Grid: UTM Zone 31N, WGS84 Scale: 1:250, E E N Chart showing location of relevant report figures