23 Offshore and Inter-Tidal Archaeology 23 OFFSHORE AND INTER-TIDAL ARCHAEOLOGY 23.1 Scope of the Assessment 23.1.1 This section of the Environmental Appraisal provides an assessment of the potential impacts to submerged and inter-tidal archaeology during the construction and operational phases of the Hinkley C development. 23.1.2 Figure 23.1 shows the location of the development area and the wider study area considered in this report. 23.1.3 The geographical extent of the development area includes: the location of intake/outfall tunnel heads; and the proposed jetty site located at the western edge of Hinkley Point. 23.1.4 Both areas are contained within the box ‘Development Area’ in Figure 23.1. 23.1.5 A detailed description of the proposed development is provided in Volume 2 Chapter 2. 23.2 Objectives of the Assessment 23.2.1 The objectives of the assessment are: to identify all known heritage assets within the study area boundary below the Mean High Water Mark (MHWM); to assess the potential for submerged and buried archaeological remains and their likely level of preservation; to assess the likely extent of previous impacts on the heritage resource; to assess the potential impact of the proposed development on the heritage resource; and to recommend mitigation strategies aimed at reducing the impacts of the proposed development, if necessary. 23.3 Legislation, Policy and Guidance 23.3.1 The proposal site is located within West Somerset District. 23.3.2 Aspects of International, European and UK legislation, planning policy and guidance of relevance to the site are presented below. 23.3.3 Other relevant UK legislation, planning policy and guidance of relevance to the historic environment are outlined in Volume 2 Chapter 22. a) United Nations Convention on the Law of the Sea (UNCLOS) 23.3.4 UNCLOS became recognised as international law in 1982 and was ratified by the UK on 25 July 1997. Article 303(1) states that: HINKLEY POINT C PRE-APPLICATION CONSULTATION – STAGE 2 | 1 ENVIRONMENTAL APPRAISAL – VOLUME 2 23 Offshore and Inter-Tidal Archaeology “States have the duty to protect objects of an archaeological and historical nature found at sea and shall cooperate for this purpose.” b) Heritage (Revised) The Valetta Convention, (1992) 23.3.5 The Convention defines archaeological heritage as comprising “all remains and objects and any other traces of mankind from past epochs”. This is said to include “structures, constructions, groups of buildings, developed sites, moveable objects, monuments of other kinds as well as their context, whether situated on land or under water.” 23.3.6 This convention binds the UK to implement protective measures regarding the archaeological heritage within its jurisdiction. In particular, Article 1, which addresses inventorying and protection of sites and Article 2, which requires the mandatory reporting of chance finds and providing for “archaeological reserves” on land or underwater. c) The Protection of Wrecks Act (1973) 23.3.7 Under section one of the Protection of Wrecks Act (1973), wrecks and wreckage of historical, artistic and archaeological importance can be protected via designation. Once a wreck/area is designated it is an offence to carry out certain activities (e.g. survey or excavation) unless a licence is obtained. d) Merchant Shipping Act (1995) 23.3.8 This Act establishes the procedures for determining ownership of flotsam, jetsam, derelict and lagan found in, or on the shores of, the sea or any tidal water. If any such material is encountered and recovered it must be reported to the Receiver of Wreck. e) Protection of Military Remains Act (1986) 23.3.9 This Act automatically protects aircraft that have crashed as a part of military service. The Ministry of Defence may also choose to protect any vessel lost during military service. f) England’s Coastal Heritage: a statement on the management of coastal archaeology 23.3.10 This document sets out principles for the management of coastal archaeology. It promotes the adoption of terrestrial standards to the sub-tidal area and a commitment to in situ preservation of material where possible. g) Planning Policy Guidance Note 20, Coastal Planning (1992) 23.3.11 PPG20 covers the character of the coast, its heritage areas, other designated areas and policies for their conservation. 23.4 Methodology h) Assessment 23.4.1 The approach adopted for this assessment has been designed to comply with the requirements of the EIA Directive, relevant UK Regulations and various guidance documents detailed in Volume 1 Chapters 3 and 5, in particular, the Guidelines for Environmental Impact Assessment. 23.4.2 The assessment, and all supporting surveys have been conducted in accordance with standards and guidance issued by the Institute for Archaeologists (IfA, formerly Institute of Field Archaeologists), and English Heritage (EH). These bodies have set standards and guidance for all phases of archaeological assessment. 2 | HINKLEY POINT C PRE-APPLICATION CONSULTATION – STAGE 2 ENVIRONMENTAL STATEMENT – VOLUME 2 23 Offshore and Inter-Tidal Archaeology 23.4.3 There is, as yet, no standard or guidance published by the IfA or EH specifically relating to EIAs for the historic environment. In the absence of this, guidance on assessing the effects of roads schemes on the historic environment, given in the Design Manual for Roads and Bridges (DMRB) (Ref. 23.1), has been adapted as appropriate to inform the preparation of this chapter. 23.4.4 Assessment of the importance of heritage assets is based upon existing designations, the potential to contribute to the aims of the South West Archaeological Research Framework (Ref. 23.2), the Marine and Maritime Research Framework and the criteria described in Table 23.1, which is based on DMRB (Ref. 23.1). Table 23.1: Criteria Used to Determine the Importance of Heritage Assets Importance Description High Ancient monuments scheduled under the Ancient Monuments and Archaeological Areas Act 1979, or archaeological sites and remains of comparable quality, assessed with reference to the Secretary of State’s non-statutory criteria, referred to in PPS5. Sites protected under the Protection of Wrecks Act 1973. Wreckage covered by the Protection of Military Remains Act 1986. Well preserved sites or features not previously detected but considered to be of high importance with reference to relevant research frameworks. Medium Archaeological sites and remains which, while not of national importance, fulfil several of the Secretary of State’s criteria and are important remains in a regional context. Low Archaeological sites and remains that are of low potential or minor importance. Very Low Areas in which investigative techniques have produced negative or minimal evidence for archaeological remains, or where previous large-scale disturbance or removal of deposits can be demonstrated. Unknown Areas that may contain potential for significant archaeological remains. 23.4.5 The magnitude of impact has been based on the consequences that the proposed development will have upon the heritage resource and has been considered in terms of high, medium and low as shown in Table 23.2 (adapted from DMRB). HINKLEY POINT C PRE-APPLICATION CONSULTATION – STAGE 2 | 3 ENVIRONMENTAL APPRAISAL – VOLUME 2 23 Offshore and Inter-Tidal Archaeology Table 23.2: Criteria Used to Determine the Magnitude of Impact Magnitude Impact High Complete removal of an archaeological site. Severe transformation of the setting or context of an archaeological monument or significant loss of key components in a monument group. Medium Removal of a major part of an archaeological site’s area and loss of research potential. Partial transformation of the setting or context of an archaeological site or partial loss of key components in a monument group. Introduction of significant noise, vibration levels or scour to an archaeological monument leading to changes to amenity use, accessibility or appreciation of an archaeological site. Diminished capacity for understanding or appreciation (context) of an archaeological site. Low Removal of an archaeological site where a minor part of its total area is removed, but that the site retains a significant future research potential. Minor change to the setting of an archaeological monument. Very Low No significant physical impact or change. No significant change in setting or context. No impact from changes in use, amenity or access. i) Sources of Information 23.4.6 Heritage assets were identified through analysis and, where appropriate, modelling of the data sets shown in Figure 23.2. Baseline data used in this assessment was collected between 2008 and 2010. j) Consultation 23.4.7 Consultation has been undertaken with appropriate Statutory Bodies, comprising Somerset County Council and English Heritage. 23.4.8 Meetings were held with the English Heritage Marine Planner and the Regional Scientific Advisor for the South West Region to discuss all stages of the assessment. k) Limitations and assumptions 23.4.9 Detailed designs and construction methodologies for the proposed jetty and the intake/outfall tunnels are still being developed. 23.4.10 Potential impacts have been assessed using the data available at this time and will be revised once the detailed designs are finalised. 23.4.11 Details of dredging requirements are being finalised. Assessment of dredging impacts will be included in the ES to accompany the Development Consent Order (DCO) submission. 23.4.12 Impacts to the settings of heritage assets have not been considered in this assessment. These are considered in Volume 22, Chapter 22. 4 | HINKLEY POINT C PRE-APPLICATION CONSULTATION – STAGE 2 ENVIRONMENTAL STATEMENT – VOLUME 2 23 Offshore and Inter-Tidal Archaeology 23.5 Baseline Environmental Characteristics a) Geological Background and Marine Environment 23.5.1 The study area lies on the Somerset coast, incorporating the southern and western edges of Bridgwater Bay, and comprising part of the Outer Severn Estuary.