The Sizewell C Project 6.3 Volume 2 Main Development Site Chapter 23 Marine Historic Environment Appendices 23A - 23C Revision: 1.0 Applicable Regulation: Regulation 5(2)(a) PINS Reference Number: EN010012 May 2020 Planning Act 2008 Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations 2009 SIZEWELL C PROJECT – ENVIRONMENTAL STATEMENT NOT PROTECTIVELY MARKED VOLUME 2, APPENDIX 23A – OFFSHORE AND INTERTIDAL HISTORIC ENVIRONMENT DESK-BASED ASSESSMENT NOT PROTECTIVELY MARKED Volume 2 Appendix 23A Offshore and Intertidal Historic Environment Desk-based Assessment | NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Sizewell C: Offshore and Intertidal Historic Environment Desk-Based Assessment 34882-C-001 NOT PROTECTIVELY MARKED Report Number 34882-C-001 ii Issue 03 Issue No. 3 October 2014 Date October 2014 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Sizewell C: Offshore and Intertidal Historic Environment DBA Contents Abbreviations and Acronyms iii Executive Summary iv 1 Introduction 1 1.1 Background 1 2 Methodology 2 2.1 Study Area 2 2.2 Scope of this Assessment 2 2.3 Objectives 2 3 Legislation, Policy and Guidance 4 3.1 International Legislation 4 3.2 European Legislation 4 3.3 UK Legislation, Policy and Guidance Notes 5 3.4 Regional and Local Planning Policies and Guidance 7 4 Baseline Environmental Characteristics 9 4.1 Introduction 9 4.2 Previous offshore bathymetric and sub-bottom seismic surveys 10 4.3 Pre-Quaternary and Pleistocene Deposits 10 4.4 Holocene Deposits 13 4.5 Sea-Level History for the Study Area 22 4.6 Modern Coastal Processes and Sediment Dynamics 22 5 Archaeological and Historical Background 27 5.2 Statutory Designations 28 5.3 Period Summaries 29 5.4 Palaeolithic (c. 900,000 BC to 10,000 BC) 29 5.5 Mesolithic (c. 8,700 BC to 4,000 BC) 31 5.6 Neolithic (c. 4,000 BC to 2,000 BC) 32 5.7 Bronze Age (c. 2,000 BC to 700 BC) 33 5.8 Iron Age (c. 700 BC to AD 43) 34 5.9 Romano-British (AD 43 to AD 450) 35 5.10 Early-medieval (AD 450 to AD 1066) 36 5.11 Medieval (AD 1066 to AD 1540) 37 5.12 Post-medieval (AD 1540 to AD 1899) 41 5.13 Modern (20th century onwards) 47 6 Conclusions and Recommendations 53 7 References 54 Tables Table 2.1 Digital data sources used within the DBA 3 Report Number 34882-C-001 i Issue No. 3 Date October 2014 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Sizewell C: Offshore and Intertidal Historic Environment DBA Figures 2.1 Marine Archaeology DBA Study Area. 4.1 Distribution of offshore borehole and core records. 4.2 Distribution of previous seismic sub-bottom surveys. 4.3 Cross-section of Crag deposits (modified from Cullen et al, 2010) and 2013 boreholes projected onto the survey line. 4.4 Coralline Crag outcrop visible in the swath bathymetry data, with corresponding positive identification in boreholes. 4.5 Extent of offshore alluvial deposits in the southern half of the study area, mapped by Brew (1990) and Lees (1980). 4.6 Extent of offshore alluvial deposits in the northern half of the study area, mapped by Brew (1990) and Lees (1980). 4.7 Pollen assemblages from offshore and onshore organic deposits found within the study area. 4.8 Interpretation of the Dunwich Inner Infill and marginal deposits (modified from Lees 1982). 4.9 Thickness of Unit 2 (bank sands) of the Sizewell and Dunwich Banks (from Lees 1977). 4.10 Sizewell C deposit model: a) borehole stratigraphy; b) modelled stratigraphic units, showing Holocene palaeochannel. 4.11 Local sea-level curve derived from dated transgressive / regressive boundaries within boreholes from within the study area. Plotted against the relative sea level curve for East Anglia. 4.12 2009 swath bathymetry and backscatter surveys of the Sizewell-Minsmere coastline. 5.1 The known archaeological resource for the offshore, inter-tidal and terrestrial study area. 5.2 Designated archaeological sites. 5.3 Palaeolithic find spot. 5.4 Distribution of Neolithic sites. 5.5 Bronze Age sites and find spot distribution. 5.6 Iron Age site distribution. 5.7 Roman site distribution. 5.8 Early medieval site distribution. 5.9 Distribution of significant medieval sites and find spots. 5.10 Distribution of significant post-medieval sites and wrecks. 5.11 Swath bathymetry and backscatter data: an area of irregular seabed. 5.12 The Dunwich Bank wreck. 5.13 Linear anomaly off Sizewell Beach. 5.14 Distribution of significant modern sites and wrecks 5.15 Distribution of previously recorded geophysical anomalies within the study area. 5.16 Probable location of the Eva Witte (UKHO 10333 / NMR 1524839) 5.17 Wreck of the Mangara (UKHO 10325 / NMR 912882) 5.18 Unknown wreck at 653430 259375 5.19 Possible wreck at 651272 263395 5.20 Unknown wreck at 653632 258039 5.21 Wreck of the SS Phryne (UKHO 10312 / NMR 912874) 5.22 Wreck, most likely the SS Dulwich (UKHO 10290 / NMR 912706) 5.23 Wreck UKHO 10273 / NMR 912697, possibly the HMS New Comet 5.24 Seabed anomaly at 656704 255019 5.25 Known shipwrecks to the south of the Greater Gabbard and Galloper export cable surveys. Report Number 34882-C-001 ii Issue No. 3 Date October 2014 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Sizewell C: Offshore and Intertidal Historic Environment DBA Abbreviations and Acronyms AD Anno Domini AMAAA Ancient Monuments and Archaeological Areas Act AOD Above Ordnance Datum BEEMS British Energy Estuarine and Marine Studies BGS British Geological Survey BC Before Christ cal BC Calibrated BC (calibrated radiocarbon dates) BP Before Present (AD 1950) c. Circa COARS Coastal and Offshore Archaeological Research Services DBA Desk-based assessment EA Environment Agency EIA Environmental Impact Assessment ES Environmental Statement HER Historic Environment Record HES Historic Environment Service IfA Institute for Archaeologists JNAPC Joint Nautical Archaeology Policy Committee kaBP Thousand years Before Present (AD 1950) LDF Local Development Framework LGM Last glacial maximum LIDAR Light Detection and Ranging MHWM Mean High Water Mark MIS Marine Isotope Stage MPS Marine Policy Statement MSA Merchant Shipping Act Mya Million years ago NMP National Mapping Programme NMR National Monuments Record OD Ordnance Datum ODN Ordnance Datum Newlyn OS Ordnance Survey PAS Portable Antiquities Scheme PMRA Protection of Military Remains Act PPG Planning Policy Guidance PPS Planning Policy Statement PWA Protection of Wrecks Act RCZA Rapid Coastal Zone Assessment RSS Regional Spatial Strategies SA Strategic Aim SCC Suffolk County Council SEA Strategic Environmental Assessment SM Scheduled Monument SZB Sizewell B SZC Sizewell C UNCLOS United Nations Convention on the Law of the Sea UKHO United Kingdom Hydrographic Office UXO Unexploded Ordnance WWII World War Two Report Number 34882-C-001 iii Issue No. 3 Date October 2014 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Sizewell C: Offshore and Intertidal Historic Environment DBA Executive Summary This report presents the results of the offshore and intertidal historic environment desk- based assessment for the Sizewell C Main Development Site and related development as it pertains to the marine environment. Using existing data sources, it identifies all known heritage assets below the Mean High Water Mark (MHWM), and assesses the potential for submerged and buried archaeological remains. The geographical extent of the area directly under consideration includes the site of the proposed Sizewell C new nuclear power station and the inter-tidal/sub-tidal zone adjacent to the proposed site. To facilitate an informed understanding of the data, a broader study area of approximately four hundred square kilometres was defined, with Sizewell C at its central point. The report presents a brief statement of methodology (Section 2); an outline of relevant historic environment legislation and planning guidance, both offshore and on land (Section 3). Section 4 outlines the baseline environmental characteristics of the study area, including pre-Quaternary, Pleistocene and Holocene deposits. The latter utilises both published and unpublished work and existent client reports to reconstruct the Holocene environment, focusing especially upon marine transgressions and regressions. It concludes with a discussion of modern coastal processes, bathymetry and sediment dynamics. These areas are important to understanding the submerged archaeological resource. Section 5 presents period summaries, examining the archaeological potential of the study area from the Palaeolithic to the present day. Of particular significance is the presence of the Dunwich Bank wreck, a designated wreck site of international importance situated approximately 4.5km to the north of the existing Sizewell Power Station Complex. A series of recent offshore surveys, linked to major infrastructure projects, has permitted the location of a number of wrecks, where visible upon the seabed, to be identified with certainty within the study area. This report does not provide a detailed discussion of the impact of the proposed development as development plans for offshore infrastructure at Sizewell C have not yet been finalised. At present, it is concluded that the potential for archaeological remains below MHWM is medium-high. In some locations (particularly those associated with the offshore sand banks), such archaeological remains are likely to be submerged beneath a considerable sedimentary overburden. Report Number 34882-C-001 iv Issue No. 3 Date October 2014 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Sizewell C: Offshore and Intertidal Historic Environment DBA 1 Introduction 1.1 Background 1.1.1 AMEC, commissioned by EDF Energy, appointed Coastal and Offshore Archaeological Research Services (COARS), University of Southampton, to carry out a detailed desk based assessment (DBA) of the area offshore of Sizewell. 1.1.2 The specific aims of this study were to: identify all known heritage assets within the wider marine study area boundary below the Mean High Water Mark (MHWM); identify the potential for submerged and buried archaeological remains and their likely level of preservation from existing data sources; and assess the likely extent of previous impacts on the historic environment resource.