National Grid Grain LNG Limited Grain LNG Phase 3B
APPENDIX 1.3: ARCHAEOLOGICAL DESK BASED ASSESSMENT
ES Volume 2: Technical Appendices
GRAIN LNG PHASE 3B Isle of Grain Hoo Peninsula
County of Kent
Archaeological desk based assessment
November 2020
© Museum of London Archaeology 2020 Museum of London Archaeology Mortimer Wheeler House 46 Eagle Wharf Road, London N1 7ED tel 020 7410 2200 | fax 020 410 2201 https://www.mola.org.uk general enquiries: [email protected]
GRAIN LNG PHASE 3B Isle of Grain Hoo Peninsula Kent
Archaeological Desk Based Assessment
NGR 587080 175798
Historic Environment Record search reference: Isle of Grain, Medway
Sign-off history issue Issue date Prepared by Reviewed by Project Manager Notes no. 1 03/11/2020 Melissa Cutting Rupert Featherby Philip Stastney First issue (Archaeology) Lead Consultant Archaeology 2 06/11/2020 Melissa Cutting - Philip Stastney Second issue (Archaeology) Ashley Blair (Graphics)- 3 10/11/2020 Melissa Cutting Project name revised (Archaeology)) 4 27/11/2020 Philip Stastney Philip Stastney Minor revisions, and updated site outline 5 09/12/2020 Philip Stastney Minor revision.
MOLA code: P20-345
www.mola.org.uk © MOLA Mortimer Wheeler House, 46 Eagle Wharf Road, London N1 7ED tel 0207 410 2200 email: [email protected] Museum of London Archaeology is a company limited by guarantee Registered in England and Wales Company registration number 07751831 Charity registration number 1143574 Registered office Mortimer Wheeler House, 46 Eagle Wharf Road, London N1 7ED Contents
Executive summary 1
1 Introduction 2 1.1 Origin and scope of the report 2 1.2 Designated heritage assets 2 1.3 Aims and objectives 3
2 Methodology and sources consulted 4 2.1 Sources 4 2.2 Methodology 4
3 The site: topography and geology 6 3.1 Site location 6 3.2 Topography and geology 6
4 Archaeological and historical background 8 4.1 Overview of past investigations 8 4.2 Chronological summary 8
5 Statement of significance 14 5.1 Introduction 14 5.2 Factors affecting archaeological survival 14 5.3 Archaeological potential, and significance of likely remains 17
6 Impact of proposals 19 6.1 Proposals 19 6.2 Implications 19
7 Conclusion and recommendations 21
8 Gazetteer of known historic environment assets 22
9 Planning framework 27 9.1 National Planning Policy Framework 27 9.2 Local planning policy 29
10 Determining significance 31
11 Non-archaeological constraints 32
12 Glossary 33
13 Bibliography 35 13.1 Published and documentary sources 35 13.2 Other Sources 36 13.3 Cartographic sources 36 13.4 Available site survey information checklist 36
Archaeological Desk Based Assessment © MOLA 2020 i Grain LNG Phase 3B3B 09/12/2020 Figures
Cover: Grain Parish Tithe Map of 1839
Fig 1 Site location Fig 2 Historic environment features map Fig 3 Geological features, geotechnical survey data (Soil Mechanics 2010) and historic borehole data (BGS 2020) map Fig 4 Grain Parish Tithe Map of 1839 Fig 5 Ordnance Survey 1st edition 5”: mile map of 1863 Fig 6 Ordnance Survey 1:2,500 scale map of 1967 Fig 7 Ordnance Survey 1:10,000 scale map of 1993 Fig 8 Site Layout, showing existing site and surrounding area layout and proposed new T355 Tank location (National Grid 2020) Fig 9 Tank Layout Plan showing existing and proposed Phase 3B construction (National Grid, PL3/PLA/108, Rev A1, 31/08/2007) Fig 10 LNG Storage Tank Section and Plan View (National Grid, Figure 3.3, June 2006)
Note: site outlines may appear differently on some figures owing to distortions in historic maps. North is approximate on early maps.
Archaeological Desk Based Assessment © MOLA 2020 ii Grain LNG Phase 3B3B 09/12/2020 Executive summary
National Grid Grain LNG Limited has commissioned MOLA to carry out an Archaeological Desk Based Assessment in advance of development at the Grain LNG Importation Facility, Isle of Grain in the County of Kent in support of the discharge of planning conditions for Phase 3B. The scheme comprises the construction of a LNG storage tank, installation of three submerged combustion vaporisers and provision of related infrastructure, including a temporary laydown area for the construction phase of the LNG storage tank and associated plant, referred to as “Phase 3B”. Grain LNG Phase 3B received permission under wider proposals which also included the construction of a jetty, internal access roads and other infrastructure. These components and the first LNG storage tank have already been built (i.e. Phase 3A). This assessment will focus on the site of the second permitted LNG storage tank and associated laydown area south and east of the tank location which are proposed and have not yet been constructed. This desk-based study assesses the impact of the scheme on archaeological remains (buried heritage assets). Above ground heritage assets (historic structures) are not discussed in detail, but they have been noted where they assist in the archaeological interpretation of the site. Archaeological remains that may be affected by the proposals comprise: • Palaeoenvironmental evidence. The geology of the Phase 3B area is comprised of thick alluvial deposits with lenses of peat and organic material. There is high potential for encountering remains of likely geoarchaeological interest which can be utilised to reconstruct past local environments, indirect evidence of local human activity and useful data to assist our understanding of past sea level changes. Minerogenic deposits such as alluvial silts and clays have the potential for preservation of diatoms that can provide information on the salinity status of the depositional environments that would enhance interpretation of the sedimentary sequence. These remains would be of low or medium significance, depending on the presence of datable material and their historic and evidential value. • Prehistoric remains. The Phase 3B area is located within the intertidal marshland area. There is low potential for remains of associated structures such as platforms, bridge piers, jetties, and fish traps which may have been constructed. The ephemeral nature of these activities suggests that little tangible and/or visible evidence may remain. There is moderate potential for undisturbed alluvial deposits within the site which could contain evidence of successive episodes of prehistoric activity. The significance of the any prehistoric remains would depend on their nature and extent. Extensive and well preserved features may be of low to medium significance, depending on their evidential and historical value. Isolated and/or residual artefacts would likely be of low significance. There is low potential for remains from all other periods as the Phase 3B area was located in low-lying marshland prone to flooding and then existed as pastoral agricultural land during the later medieval and post-medieval periods. The Phase 3B area and surrounding area have been extensively developed and levelled since the mid-1950s during industrial expansion. The main impact from the scheme will be the piled foundation of the LNG storage tank base, which would remove archaeological/palaeoenvironmental remains within the footprint of each pile. Other site works, including obstruction removal, below ground vaporisers and other minor foundations, may also impact the upper levels of surviving alluvium deposits. The Phase 3B area is not located in an Archaeological Priority Area. Although the proposed development has high potential to contain palaeoenvironmental evidence of low to medium significance and low to moderate potential to contain prehistoric remains of low to medium significance, in light of the localised area of the proposed impact, it is unlikely that the local authority would require further preliminary site-specific archaeological evaluation. It is likely, however, that given the uncertainty of site-specific geological remains archaeological monitoring of intrusive works (below ground) would be requested in order to confirm the precise level of natural deposits along with presence and depth of any archaeological remains. The previously proposed mitigation of a watching brief, as recommended during the 2006 and 2007 assessments, remains appropriate. Any archaeological work would need to be undertaken in accordance with an approved Written Scheme of Investigation (WSI) and be carried out under the terms of Discharge of Condition 27 as set out in decision notice MC/07/1683.
Archaeological Desk Based Assessment © MOLA 2020 1 Grain LNG Phase 3B3B 09/12/2020 1 Introduction
1.1 Origin and scope of the report
1.1.1 National Grid Grain LNG Limited has commissioned MOLA (Museum of London Archaeology) to prepare an Archaeological Desk Based Assessment in advance of development at the Grain LNG Importation Facility, Isle of Grain in the County of Kent; National Grid Reference (NGR) 587080 175798: Fig 1. It has been prepared in support of the discharge of planning conditions (Planning Ref: MC2007/1683, amendment of MC2006/1428) for the construction of Phase 3B at the Grain LNG Importation Facility on the Isle of Grain, Kent. 1.1.2 The scheme comprises the construction of a LNG storage tank, the installation of three submerged combustion vaporisers and the provision of related infrastructure, including a temporary laydown area for the construction phase of the LNG storage tank and associated plant. Grain LNG Phase 3B (sitting within an area formerly known as Phase 3 Northern Zone) received permission under wider proposals which also included the construction of a jetty, internal access roads and other infrastructure. These components and the first LNG storage tank have already been built. This assessment will focus on the site of the second permitted LNG storage tank and associated laydown area south and east of the tank location. 1.1.3 This desk-based study assesses the impact of the scheme on archaeological remains (buried heritage assets). It forms an initial stage of investigation of the area of development (hereafter referred to as ‘Phase 3B area’) and may be required in relation to the planning process in order that the local planning authority (LPA) can formulate an appropriate response in the light of the impact on any known or possible heritage assets. These are parts of the historic environment which are considered to be significant because of their historic, evidential, aesthetic and/or communal interest. 1.1.4 This report deals solely with the archaeological implications of the development and does not cover possible built heritage issues, except where buried parts of historic fabric are likely to be affected. Above ground assets (i.e., designated and undesignated historic structures and conservation areas) in the Phase 3B area or in the vicinity that are relevant to the archaeological interpretation of the site are discussed. Whilst the significance of above ground assets is not assessed in this archaeological report, direct physical impacts upon such assets arising from the development proposals are noted. The report does not assess issues in relation to the setting of above ground assets (e.g., visible changes to historic character and views). 1.1.5 The assessment has been carried out in accordance with the requirements of the National Planning Policy Framework (NPPF) (MHCLG 2019; see section 9 of this report) and to standards specified by the Chartered Institute for Archaeologists (CIfA 2014, 2017) and Historic England (EH 2008, HE 2015). Under the ‘Copyright, Designs and Patents Act’ 1988 MOLA retains the copyright to this document. 1.1.6 Note: within the limitations imposed by dealing with historical material and maps, the information in this document is, to the best knowledge of the author and MOLA, correct at the time of writing. Further archaeological investigation, more information about the nature of the present buildings, and/or more detailed proposals for redevelopment may require changes to all or parts of the document.
1.2 Designated heritage assets
1.2.1 Historic England’s National Heritage List for England (NHL) is a register of all nationally designated (protected) historic buildings and sites in England, such as scheduled monuments, listed buildings and registered parks and gardens. The NHL does not include any nationally designated heritage assets within the Phase 3B area. The closest designated asset to the Phase 3B area is the Grade II listed Grain Crossing signal box (NHL1415162), 925m to the south-west. The Phase 3B area is situated approximately 2.2km west of a Scheduled Monument (NHL1019955), comprising coastal artillery defences east and south-east of the village of Grain.
Archaeological Desk Based Assessment © MOLA 2020 2 Grain LNG Phase 3B3B 09/12/2020 1.2.2 The Phase 3B area is located c 710m south of the Medway Estuary and Marshes Special Protection Area (SPA), which is also a Ramsar site (protected wetland) and Site of Special Scientific Interest (SSSI). 1.2.3 The Phase 3B area is not within any Area of Archaeological Interest as defined by the local authority. 1.3 Aims and objectives
1.3.1 The aim of the assessment is to: • identify the presence of any known or potential buried heritage assets that may be affected by the proposals; • describe the significance of such assets, as required by national planning policy (see section 9 for planning framework and section 10 for methodology used to determine significance); • assess the likely impacts upon the significance of the assets arising from the proposals; and • provide recommendations for further assessment where necessary of the historic assets affected, and/or mitigation aimed at reducing or removing completely any adverse impacts upon buried heritage assets and/or their setting.
Archaeological Desk Based Assessment © MOLA 2020 3 Grain LNG Phase 3B3B 09/12/2020 2 Methodology and sources consulted
2.1 Sources
2.1.1 For the purposes of this report, documentary and cartographic sources including results from any archaeological investigations in the Phase 3B area and the area around it were examined in order to determine the likely nature, extent, preservation and significance of any buried heritage assets that may be present within the site or its immediate vicinity. This information has been used to determine the potential for previously unrecorded heritage assets of any specific chronological period to be present within the site. 2.1.2 In order to set the Phase 3B area into its full archaeological and historical context, information was collected on the known historic environment features within a 1km-radius study area around it, as held by the primary repositories of such information within Kent. These comprise the Kent Historic Environment Record (KHER) and the Museum of London Archaeological Archive (MoL Archaeological Archive). The KHER is managed by Kent County Council (KCC) and includes information from past investigations, local knowledge, find spots, and documentary and cartographic sources. The MoL Archaeological Archive includes a public archive of past investigations and is managed by the Museum of London. The study area was considered through professional judgement to be appropriate to characterise the historic environment of the Phase 3B area. Occasionally there may be reference to assets beyond this, where appropriate, e.g., where such assets are particularly significant and/or where they contribute to current understanding of the historic environment. 2.1.3 The extent of investigations as shown on Fig 2 may represent the site outline boundary for planning purposes, rather than the actual area archaeologically investigated. Where it has not been possible from archive records to determine the extent of an archaeological investigation (as is sometimes the case with early work), a site is represented on Fig 2 only by a centrepoint. 2.1.4 In addition, the following sources were consulted: • MOLA – in-house Geographical Information System (GIS) with statutory designations GIS data, the locations of all ‘key indicators’ of known prehistoric and Roman activity across Greater London, past investigation locations, projected Roman roads; burial grounds from the Holmes burial ground survey of 1896; georeferenced published historic maps; Defence of Britain survey data, in-house archaeological deposit survival archive and archaeological publications; • Historic England – information on statutory designations including scheduled monuments and listed buildings, along with identified Heritage at Risk; • Groundsure – historic Ordnance Survey maps from the first edition (1860–70s) to the present day; • British Geological Survey (BGS) – solid and drift geology digital map; online BGS geological borehole record data; • Project briefing from National Grid (Greengage, 10/09/2020), ES Briefing Note (Greengage 09/2020) and ground investigation report (Soil Mechanics, 2010); • Internet – web-published material including the LPA local plan, and information on conservation areas and locally listed buildings. 2.1.5 A site visit was not considered necessary. Plans of the existing structures were available for the assessment.
2.2 Methodology
2.2.1 Fig 2 shows the location of known historic environment features within the study area. These have been allocated a unique historic environment assessment reference number (DBA 1, 2, etc), which is listed in a gazetteer at the back of this report and is referred to in the text. Where there are a considerable number of listed buildings in the study area, only those within the
Archaeological Desk Based Assessment © MOLA 2020 4 Grain LNG Phase 3B3B 09/12/2020 vicinity of the Phase 3B area (i.e. within 100m) are included, unless their inclusion is considered relevant to the study. Conservation areas and archaeological priority areas are not shown. All distances quoted in the text are approximate (within 5m) and unless otherwise stated are measured from the approximate centre of the Phase 3B area. 2.2.2 Section 10 sets out the criteria used to determine the significance of heritage assets. This is based on four values set out in Historic England’s Conservation principles, policies and guidance (EH 2008), and comprise evidential, historical, aesthetic and communal value. The report assesses the likely presence of such assets within (and beyond) the site, factors which may have compromised buried asset survival (i.e. present and previous land use), as well as possible significance. 2.2.3 Section 11 includes non-archaeological constraints. Section 11.1.1 contains a glossary of technical terms. A full bibliography and list of sources consulted may be found in section 13 with a list of existing site survey data obtained as part of the assessment.
Archaeological Desk Based Assessment © MOLA 2020 5 Grain LNG Phase 3B3B 09/12/2020 3 The site: topography and geology
3.1 Site location
3.1.1 The Phase 3B area is located on the Isle of Grain in Medway, Kent, within a larger area of land currently owned and used as a Grain LNG importation facility, between the estuaries of the River Thames and Medway, within the eastern extent of the Hoo Peninsula (NGR 587080 175798: Fig 1). The Phase 3B area covers an area of 4.0ha and the adjacent construction laydown area to the south east covers an area of 6.0ha; these areas are bounded by an existing National Grid Grain LNG storage tank to the north-west and additional National Grid Grain LNG facilities to the south, Grain Road to the east and open fields to the north. The Phase 3B area falls within the historic parish of ‘Graine’ or Grain, within the county of Kent, prior to being absorbed into the administration of the borough of Medway. 3.1.2 The Phase 3B area is located 2.2km north of the nearest stretch of coastline.
3.2 Topography and geology
3.2.1 Topography can provide an indication of suitability for settlement, and ground levels can indicate whether the ground has been built up or truncated, which can have implications for archaeological survival. The underlying natural geology of a site can also provide an indication of suitability for early settlement, and potential depth of remains. 3.2.2 Legacy OS (Ordnance Survey) spot heights within the study area are limited to elevations taken along Grain Road to the east and south. It shows that the ground level in the study area rises gradually from 3.1m OD c 975m south of the Phase 3B area to 10.6m OD along a north- eastern route towards the gravel island of the Isle of Grain. The ground level of the village of Grain, situated on higher ground, some 1.8km north-east of the Phase 3B area, is at c. 11– 12m OD. The Phase 3B area is relatively flat and low-lying; it has been raised in level from its former land uses. Some stockpiles of spoil from other works are also present on site (Soil Mechanics 2010). 3.2.3 Site-specific topographic information on the location of the of the proposed LNG storage tank in the northern quarter of the Phase 3B area is included in the Soil Mechanics 2010 Factual Report on Ground Investigation. The Factual Report on Ground Investigation shows the topography of the storage tank location slopes upward to the south from 2.3m OD to 3.2m OD. A single historic borehole has also been conducted within the eastern corner of the adjacent construction laydown area (TQ87NE43), at a ground level of 5.1m OD. This indicates that the rest of the site continues sloping upward toward the south, and likely the eastern portion of the site also begins to slope upward to the east, towards the gravel island of the Isle of Grain. 3.2.4 The Phase 3B area sits within a larger area of land currently owned and used by the applicant as a Grain LNG importation facility, which was formerly a BP oil refinery, decommissioned in 1984. The Phase 3B area has likely been levelled for previous construction and is surrounded by extensive, low-lying remnants of former large-scale industrial complexes now derelict and unmanaged. The dominant feature in the landscape, the Grain Power Station, was decommissioned in 2012. 3.2.5 The British Geological Survey (BGS) digital data shows that the Phase 3B area lies immediately west and south-west of an elevated gravel island, where the village of Grain is located. The geology of the site comprises tertiary bedrock of the London Clay Formation, which is overlain in the western three quarters of the site by Quaternary alluvium containing lenses of peat and capped by modern made-ground/ topsoil overburden. In the eastern quarter of the site, Head Deposits, also formed during the Quaternary Period, are mapped over the London Clay. 3.2.6 The Phase 3B area is located to the south-west of the Isle of Grain, an outcrop or island of river terrace gravels formed at the confluence of the River Medway and the River Thames. Alluvial sediments would have built up across the area through the interaction of the marine and fluvial environments. A mosaic of different habitats and ecotonal environments would have existed at this interface. Palaeochannels likely flowed to the north of the site boundary into the
Archaeological Desk Based Assessment © MOLA 2020 6 Grain LNG Phase 3B3B 09/12/2020 river, incising channels in the underlying London Clay. 3.2.7 The depth of natural geology in the Phase 3B area as an indicator of possible archaeological survival is discussed in detail in section 5.2.
Archaeological Desk Based Assessment © MOLA 2020 7 Grain LNG Phase 3B3B 09/12/2020 4 Archaeological and historical background
4.1 Overview of past investigations
4.1.1 The KHER notes 11 past investigations which have been carried out within the 1km study area surrounding the Phase 3B area, mostly limited to the south and south-east, except two walk- over surveys and aerial photographic and LiDAR survey which covered much of the Isle of Grain (DBA 1a). These investigations mostly comprise geoarchaeological surveys, watching briefs, and landscape surveys. Geoarchaeological borehole monitoring provides valuable information about geological sequences that can be used to infer changes to sea level, climate, and vegetation from the early Holocene to the present day. However, predominate use of this method of investigation has resulted in an unrepresentative archaeological record. Borehole monitoring investigates a specific form of data and will not capture and record the full-extent of archaeological features. Furthermore, the spatial representation of borehole monitoring is relatively poor as data can only be captured within the footprint of each borehole. No formal archaeological excavation has been undertaken within the Phase 3B area or study area. Much of the artefactual record has been derived from chance observations during ground works in the early 20th century (Evans, 1950). This has likely resulted in the removal of stratigraphic understanding at these sites of discovery. Other artefacts have been discovered by metal detectorists, operating under the Portable Antiquities Scheme. Equally, stratigraphic relationships at these sites are unlikely to have been recorded and are therefore considered lost. Currently understanding of past human activity within the study area is limited, particularly of prehistoric, Roman, early medieval periods. 4.1.2 The Phase 3B area and surrounding area were part of three large scale assessments of the Hoo Penisula: two walkover surveys and an historic landscape assessment (DBA 1a). The two walkover surveys were conducted in 2001 and 2004, as part of the North Kent Coast Rapid Coastal Zone Assessment Survey and of the Grain Power Station as part of proposed new plant, respectively. There is no further information available regarding the earlier survey and the later recorded no archaeological features or remains. In 2009–12 Historic England undertook an aerial photographic and Lidar mapping assessment of the Hoo Peninsula, which recorded archaeological features dating from the prehistoric to modern era. 4.1.3 The closest past investigations involving ground disturbance are two watching briefs 140m south of the southern boundary of the Phase 3B area and laydown. During monitoring of groundworks associated with the removal of contaminated soils and deep drilling at Grain Power Station in 2007, no archaeological remains were observed (DBA 2). Along Grain Road in 2003, 13 geotechnical test pits extending to 0.9m below ground level (bgl) were monitored (DBA 3). No archaeological remains were identified however likely alluvial deposits were encountered. 4.1.4 The results of these investigations, along with other known sites and finds within the study area, are discussed by period, below. The date ranges given are approximate.
4.2 Chronological summary
Prehistoric period (800,000 BC–AD 43) 4.2.1 The Lower (800,000–250,000 BC) and Middle (250,000–40,000 BC) Palaeolithic saw alternating warm and cold phases and intermittent perhaps seasonal occupation. During the Upper Palaeolithic (40,000–10,000 BC), after the last glacial maximum, and in particular after around 13,000 BC, further climate warming took place and the environment changed from steppe-tundra to birch and pine woodland. It is probably at this time that Britain first saw continuous occupation. Erosion has removed much of the Palaeolithic land surfaces and finds are typically residual. There are no known finds dated to this period within the study area. 4.2.2 The Mesolithic hunter-gatherer communities of the postglacial period (10,000–4000 BC) inhabited a still largely wooded environment. The river valleys and coast would have been favoured in providing a dependable source of food (from hunting and fishing) and water, as well as a means of transport and communication. Evidence of activity is characterised by flint
Archaeological Desk Based Assessment © MOLA 2020 8 Grain LNG Phase 3B3B 09/12/2020 tools rather than structural remains. There is no known artefactual evidence dated to this period within the study area, however palaeoenvironmental evidence within deep alluvial and peat deposits may be present. Marine transgressions (rise in sea level) at the end of the early prehistoric period resulted in inundation of the low-lying areas, creating an intertidal marshland landscape crossed by numerous small creeks and fleets. Areas of open marsh, reed formation and small outcrops of woodland would have also existed. This would have made permanent occupation difficult except for areas of higher ground (Rippon 2000, 1). 4.2.3 The Neolithic (4000–2000 BC), Bronze Age (2000–600 BC) and Iron Age (600 BC–AD 43) are traditionally seen as the time of technological change, settled communities and the construction of communal monuments. Farming was established and forest cleared for cultivation. An expanding population put pressure on available resources and necessitated the utilisation of previously marginal land. 4.2.4 Three undated cropmarks of ring ditches have been identified by aerial photography and Google Earth Imagery (DBA 29–31), 500-740m north-east of the Phase 3B area. The ring ditches are not dated but likely date to the Bronze or Iron Age. 4.2.5 Excavations (Britannia XIII, 1982, 393–395) undertaken by the Kent Archaeological Rescue Unit approximately 1.9km north-east of the site (beyond the study area), along the north edge of the gravel island recorded evidence of an Iron Age settlement, comprising enclosure ditches, post-holes, refuse pits and occupation layers. 4.2.6 The Phase 3B area and surrounding area lay within the intertidal marsh characterised with several, possibly braided, palaeochannels. The marshland would have been unsuitable for settlement but likely have been used for a broad range of activities typically observed within the Thames and Medway basins, including grazing, fishing, fowling, and salt exploitation. Resources such as willows, reeds and rushes would likely have been exploited as well as clays for pottery manufacture. There is, however, no known evidence of these activities within the study area. Evidence of these periods is more likely to be derived from deep alluvial and peat sequences.
Roman period (AD 43–410) 4.2.7 At this time, as with earlier periods, the Phase 3B area was situated on low-lying intertidal marshland that is unlikely to have attracted substantial habitation. Settlements are more likely to have been situated on higher-ground like the gravel island 330m north-east of the site boundary. The 1981 excavation undertaken on northern edge of the gravel island, c 1.9km north-east of the site boundary (Britannia XIII, 1982, 393–395) recorded a late Roman cemetery of at least 47 individual inhumations. The associated grave goods provided a tentative date-range of 250–300 AD. The implication that it is highly likely that a small agricultural settlement would have been situated nearby. 4.2.8 Evans (1950, 145–146) notes that extensive ground works undertaken in the early 20th century by the Anglo-Iranian Oil Company, approximately 835m east of the Phase 3B area (DBA 28), revealed evidence of Iron Age and Romano-British occupation. Roman brick was observed within a deposit of burnt clay along with a single pot sherd, identified by Mr. E. Greenfield as an Iron Age South-Eastern B type likely belonging to an omphalos bowl. Evan’s observations regarding this site were made several years after the event and it is likely that stratigraphic understanding following unwitting destruction by ground works. However, Evan’s did investigate another area (DBA 28), ‘only a few yards to the east’ (Evans 1950, 146), where he recorded a large pit filled with hundreds of oyster, whelk and cockle shells, along with skeletal remains of ox and sheep. Pot sherds were also encountered and identified as provincial Roman domestic ware. 4.2.9 Two Roman cordoned flasks dating to the 1st–2nd centuries were found in 1951 during excavations for the Anglo Iranian Oil Company, 400m north-east and 900m south of the Phase 3B area (DBA 14 and 26). The southern location also revealed two gold quarter stater coins, weighing approximately 1.3 grams each, recovered by workmen. These were identified as belonging to the late Iron Age. It is impossible to discern whether these artefacts were encountered in-situ or were residual. Consequently, it is not possible to affirm Roman occupation with this evidence. However, coupled with the evidence cited above, it is plausible that the area was utilised during the Roman period. The coastal marshes were important areas of economic activities during this period, including pottery manufacturing and salt-making
Archaeological Desk Based Assessment © MOLA 2020 9 Grain LNG Phase 3B3B 09/12/2020 industries, along with oyster fishing and salt boiling used in the processing of fish, rough grazing and farming (Monoghan 1987, 18). 4.2.10 North Kent marshes on the Thames Estuary to the north-west was a notable centre of pottery manufacture, with production sites located on marshland, below the water table, or below high tide marks in the estuaries (Monaghan 1987, 10). The alluvial clay provided the raw material for the pottery and shell and sand were used for the temper. Most of the known kiln sites in the region are located adjacent to navigable creeks, which were used to transport the finished products (ibid, 18). A possible Roman (or medieval) pottery kiln was found by workmen in 1939 while digging a trench to take an oil pipeline “south of Wallend Farmhouse”, approximately 950m south-east of the Phase 3B area (DBA 27). The finds included kiln bricks and potsherds at a depth of “3 and 4 feet OD”. Other Roman remains within the marshland might include causeways, waterfront installations, evidence of salt manufacture (from evaporation), mills and boats.
Early medieval (Saxon) period (AD 410–1066) 4.2.11 Following the withdrawal of the Roman administration from England in the early 5th century AD there was a period of relative socio-economic decline. Germanic (‘Saxon’) settlers arrived from mainland Europe, with occupation in the form of small villages and an economy initially based on agriculture. By the end of the 6th century a number of Anglo-Saxon kingdoms had emerged, and as the ruling families adopted Christianity, endowments of land were made to the church. Landed estates (manors) can be identified from the 7th century onwards; some, as Christianity was widely adopted, with a main ‘minster’ church and other subsidiary churches or chapels. In the 9th and 10th centuries, the Saxon Minster system began to be replaced by local parochial organisation, with formal areas of land centred on settlements served by a parish church. 4.2.12 The etymology of the ‘Isle of Grain’ is most likely derived from the Anglo-Saxon word Greon, meaning ‘gravel’ or ‘sandy ground’. There may have been a small settlement on the island. The surrounding marshes, including the site, would have been marshland prone to flooding. As with other periods, the marshland was probably exploited for various riverine resources. 4.2.13 The Domesday Book (1086) notes that prior to the Norman Conquest of 1066 the Manor of Gillingham was under the control of the Archbishop of Canterbury. The Isle of Grain at this time was within the Churches possession and formed an additional part of the Manor of Gillingham (Hasted, 1798, 226–249). 4.2.14 The KHER notes the chance discovery of two Saxon coins by a metal detectorist in 1984 along the western boundary of the Phase 3B area (DBA 1b). Both coins were silver sceattas, deriving from the Old English word ‘Sceatt’, meaning ‘wealth’ or ‘coin’. One coin was identified as one of the London series, diademed bust to the right and cup in foreside. On the reverse side the coin face displayed the image of a king with head turned to the right, holding a cross in one hand and a bird in the other. This coin was dated to the 8th–9th centuries. The other coin is a ‘Kentish’ type dated to circa. 690–725 AD. The identity of the ruler, mint and moneyer of either coin is uncertain. Similar to the Roman artefactual evidence, it is unclear in what context they were found in, what the relationship between the coins may be, or whether they were residual finds. The KHER cites that one coin was discovered beneath ‘an old wall’, while the other was found on the gravel island. 4.2.15 Approximately 215m west of the western boundary of the Phase 3B area a large copper-alloy D-shaped cast buckle, measuring 45mm in length and 40mm in width, was unearthed by a metal detectorist under the Portable Antiquities Scheme in a complete and good condition (DBA 9). The buckle is thought to be of late Saxon date, likely 900–1100 AD. A decorated pin rests in a square housing on the frame that has a zoomorphic knob. The buckle face had an intricate decoration depicting ‘biting beasts’. The frame of the buckle is fashioned like the segmented or furry necks of two dragons or other beasts; their jaws grip the bar around which the strap fitted. Similarly to the evidence presented above the context in which this find was discovered is uncertain. The limitations of the current archaeological record means little can be confidently ascribed as evidence of occupation and activity during the Early Medieval period. The most likely evidence of this period would derive from geoarchaeological remains within alluvial deposits that would help detail climate conditions and vegetation types during this period.
Archaeological Desk Based Assessment © MOLA 2020 10 Grain LNG Phase 3B3B 09/12/2020 Later medieval period (AD 1066–1485) 4.2.16 The site was situated within the parish of ‘Graine’. The church of St James’ in the village of Grain, approximately 2.0km north-east of the Phase 3B area, is dated to the 13th century. The church served a small settlement on the gravel island. The Isle of Grain remained in the possession of the Archbishopric of Canterbury until the reign of Queen Elizabeth I in the late 16th century (Hasted, 1798, 226–249). 4.2.17 The site and surrounding area was within the intertidal marshland and was probably drained and gradually reclaimed over this period. Reclamation is likely to have taken place in stages, with a number of successive seas walls being constructed as more and more of the marshland was reclaimed out from the edge of the higher ground. This would have provided additional fertile land for permanent grazing pastures and arable agriculture. It is likely that the site was used for these agricultural purposes throughout the medieval period. 4.2.18 Both cartographic evidence and the KHER note Redhouse Farm, Wilford’s Farm and farmsteads at Wallend (DBA 12–15, 19, and 20), in the post-medieval period, the origin of these farms is not known and they may indicate the location of earlier medieval farmsteads. 4.2.19 A small kitchen midden (DBA 17) was recorded 860m east of the Phase 3B area. Identified in the edge of a borrow pit in 1950, four shards of a 13th century jug were collected from among hundreds of oyster, whelk and cockle shells, as well as animal bones. 4.2.20 An embankment marked on the Ordnance Survey map of 1863 as ‘Hooks Wall’ extends through the southern edge of the construction laydown area and extends across the intertidal marshes from the higher ground of the gravel island. A second embankment, the ‘Old Counter Wall’, is located 785m south of the Phase 3B area. The latter provided the main access route across the marsh to the Isle of Grain from the west. These former sea walls/embankments were probably of medieval origin and would have followed the creek edges that have since been silted or infilled. No upstanding remains of the embankments were noted during a fieldwork survey undertaken in 2014 by MOLA for a Historic Environment Assessment (MOLA 2014). Above surface features were most likely levelled during 20th century development however sections of buried remains of these earthworks may be extant.
Post-medieval period (AD 1485–present) 4.2.21 At the beginning of this period the Phase 3B area and laydown was within an area of reclaimed former marshland, in an extensive area crossed by creeks, drains, gullies and flood defences. Predominant land use would have been a combination of pastoral and arable agricultural practises. 4.2.22 The significance of the Isle of Grain as a place of strategic importance was appreciated during the 16th century when a series of coastal beacons were established in the surrounding area and up the Thames valley. The site of one such beacon is noted by the KHER along the western boundary of the Phase 3B area (DBA 1b). William Lambarde’s ‘Carde’ map of circa 1570 marked a total of 52 beacons distributed along the Kent coast. These beacons were used as an early communication system that was designed to signal if the threat of invasion by foreign power was imminent, specifically Spanish or French threats. This system was generally abandoned by 1640 as the threat of Spanish invasion diminished. There is no evidence of survival of the beacon within the Phase 3B area or surrounding area. 4.2.23 The Isle of Grain continued to be used as a strategic asset into the 17th century as two coastal batteries were installed c 2.5km east-south-east of the Phase 3B area. One was named the ‘Buda Battery’ and built in circa 1688, the other was contemporary with the first and named the ‘Middle Battery’, which may imply it formed part of a series of military installations lining the coast. During the Napoleonic wars of 1803–1805 Britain anticipated an invasion and redoubts of fortified towers and fortifications were built within the Medway area. ‘Grain Tower’ (Grade II listed; NHL1204520) was constructed in 1865, c 3.0km east of the Phase 3B area. Additional batteries were built in 1867 and 1869 known as the ‘Dummy Battery’. In cooperation with Grain Fort, it was able to cross artillery fire with the guns at Sheerness. The Dummy Battery was constructed in a J-shaped earthwork. The Grain Battery was rebuilt in 1901 for four 6-inch BL guns. This fortification continued in a military use until 1935 when it was decommissioned. 4.2.24 It is unlikely that any substantial historic military footprint was established within the Phase 3B area or immediate vicinity. The Tithe map of 1839 (Fig 4) shows that ‘Old Counter Wall’ runs south and east of the Phase 3B area and laydown, following a similar alignment to present-day
Archaeological Desk Based Assessment © MOLA 2020 11 Grain LNG Phase 3B3B 09/12/2020 Grain Road, B2001, which most likely was and is the main land route from the village of Grain towards the Hoo Peninsula. The Phase 3B area was characterised by open space, likely a field system. This essentially reflected pre-existing late medieval configurations of irregular land parcels subdivided by drainage ditches and tributary channels, set behind flood defence embankments. Immediately to the north-east and east of the site was a complex of various buildings and structures representing Wallend Farm (DBA 12, 13, 14 and 15). 4.2.25 The 1st edition Ordnance Survey 6”: mile edition map of 1863 (Fig 5) shows the Phase 3B area and laydown located within fields west of Grain Road, with the southern boundary overlapping Hook’s Wall and the south-eastern corner overlapping a farm plot associated with Wallend Farm (DBA 14). The Phase 3B area was situated within irregular parcels of open land subdivided by meandering streams and drainage ditches, several within the site. Mockels Fleet waterway is immediately south of the site. To the west of the site ‘Homemarsh Pounds’ is labelled; a small timber enclosure likely for impounding sheep that grazed on the marshland. 4.2.26 Several features in the surrounding area (not shown on the extent of Fig 5) provide an indication of the other types of activities taking place in the former marshland. These include a complex of earthworks associated with ‘Old Salt Works’ (DBA 18), 790m to the north-west of the Phase 3B area. The salt works would have comprised an extensive series of clay-lined pools or trenches used to collect salt water at high tide. The water was run out for boiling in lead pans in small buildings housing furnaces. A ‘Saltpan House’ located 1.8km south-east of the Phase 3B area, beyond the study area, along the coast, is shown on late 19th century maps. This building probably contained the furnaces and racks used to lay out the salt for drying. The coastal salt industry largely disappeared at the end of the 18th century as it was not able to compete with the quality and ease of processing of mined Cheshire rock salt (Crossley 1994, 224). 4.2.27 Clay and gravel extraction on the Isle of Grain also developed during the 19th century (English Heritage, 2014, 13), as a reference in the 1851 census to a Gravel Pit House indicates. The extraction industry continued through to the early 20th century when gravel was being removed from the Yantlet area, approximately 2.0km north of the Phase 3B area and on land at Whitehall Farm, approximately 2.0km north-east of the Phase 3B area. 4.2.28 The 2nd edition Ordnance Survey 5”: mile map of 1897 and 3rd edition Ordnance Survey 5”: mile map of 1908 (not reproduced) shows no change within the Phase 3B area and laydown. The main change to the surrounding area was the construction of the Hoo Hundred Branch railway line in the late 19th century (DBA 10), running north-west to south-east, 855m to the south-west of the site. The Grain Crossing, 900m south-west of the Phase 3B area, was contemporary with the construction of the railway (DBA 21). 4.2.29 By the 20th century, numerous coastal batteries had been built in the area. During the First World War further defences against possible invasion were constructed. These included pillboxes and defensive Stop Lines (lines of enhanced defences (MacDougal 1980; RCHME 1998)). A boom defence, comprising a line of chains or similar obstacles to prevent unauthorised ship access, was constructed between Grain and Sheerness, with the Grain Tower as an anchor point. 4.2.30 The oil industry expanded on the Isle of Grain in the 20th century. Storage of oil by the Admiralty started in 1908 and in 1923 the Medway Oil and Storage Company (MOSCO; later the Power Petroleum Company) acquired land from the South Eastern Railway to open a refinery 1.0km south of the Phase 3B area and laydown. MOSCO acquired additional land in the area, part of Wallend Farm 600m east of the construction laydown area, to build a modern underground petroleum storage installation. The refinery closed in 1932 but continued to operate as a storage facility. 4.2.31 During the Second World War, the River Medway was one of the main routes for Luftwaffe aircraft towards London. The principal anti-invasion defences on the Isle of Grain comprised a series of pillboxes and defensive Stop Lines. There were various anti-aircraft batteries around the coast, some protecting specific oil depots, power stations and military installations. The KHER notes the site of a military installation 690m east of the boundary of the construction laydown area (DBA 24). No upstanding remains of this feature were noted during a field walking survey undertaken in 2014 (MOLA 2014). Grain airfield was not used directly for military activities during the war. Additionally, the KHER notes that a Luftwaffe Heinkel He 111H-2 bomber aircraft crashed on 7th September 1940 along the western edge of the Phase 3B area (DBA 1b), likely after suffering fire damage from anti-aircraft guns emplaced on the
Archaeological Desk Based Assessment © MOLA 2020 12 Grain LNG Phase 3B3B 09/12/2020 Isle of Grain, and was burnt out by the surviving crew. The crew were subsequently captured and detained by British military authorities. 4.2.32 The MOSCO’s petroleum storage installation at Wallend was eventually incorporated into the terminal for the Pipe Line Under the Ocean (PLUTO) installation. Built in 1944, PLUTO was used to move large quantities of fuel oil to the Continent. A 30-mile long 3-inch diameter pipe ran under the English Channel from a main pumping station at Dungeness. It drew fuel oil from various sites, including Grain. The terminal was located within the boundary of the former Kent Oil Refinery, approximately 700m north-east of the Phase 3B area boundary, forming a series of earth mounds that concealed the tanks. No upstanding remains of this feature were noted during a field walking survey undertaken in 2014 (MOLA 2014). 4.2.33 The Anglo-Iranian Oil Company, part of British Petroleum (BP) group, began planning for a new oil refinery at Grain in 1947. An area of marshland was purchased, including the MOSCO site and remains of Port Victoria, south of the Phase 3B area. Known as the Kent Oil Refinery, the refinery became fully operational in 1953 and continued to expand during the 1950s and 1960s, including a power station, a new railway station, several deep-water jetties and an administrative block. 4.2.34 The Ordnance Survey 1:2,500 scale map of 1967 (Fig 6) shows the dramatic change within the construction laydown area caused by the construction of the oil works. The construction laydown area has been divided into four areas, sectioned by access roads. Three of the areas contain multiple tanks and buildings, whilst the majority of the Phase 3B area is a mostly empty lot, containing only a small out building. 4.2.35 The Kent Oil Refinery was closed in 1981 and was decommissioned in 1984 as shown on the Ordnance Survey 1:2,500 scale map of 1993 (Fig 7). The majority of the above surface structures within the construction laydown area and surrounding areas have been removed. The oil refinery was purchased from BP in 1986 for the purposes of LNG importation, though not all of the area was redeveloped at this time and parts of this site remain vacant and underused, including the Phase 3B area. 4.2.36 Based on Google Earth Imagery, most of the Phase 3B area remains undeveloped. Several paved roadways intersect the site and there is chainlink fencing adjacent to the roadways. The eastern half of the construction laydown area appears to be occupied by several small temporary buildings and two parking lots.
Archaeological Desk Based Assessment © MOLA 2020 13 Grain LNG Phase 3B3B 09/12/2020 5 Statement of significance
5.1 Introduction
5.1.1 The following section discusses historic impacts on the Phase 3B area which may have compromised archaeological survival from earlier periods, identified primarily from historic maps, and information on the likely depth of deposits. 5.1.2 This is followed by an assessment of the likely potential for archaeological remains to be present in the Phase 3B area (high, moderate, low, or no potential if it is clear that any archaeological remains will have already been removed by past ground disturbance); and – in accordance with the NPPF – a statement of the significance (high, medium, low, or negligible) of the known or likely remains in the Phase 3B area. This is based on current understanding of the baseline conditions, past impacts, and professional judgement.
5.2 Factors affecting archaeological survival
Levels of natural geology, and past truncation 5.2.1 The ground level at the Phase 3B area is assumed to be between 2.3m OD and 5.1m OD, sloping upward to the south, with the construction laydown area to the east also likely sloping upward to the east, towards the elevated gravel island where the town of Grain is located. 5.2.2 A geotechnical survey was undertaken on the location of the proposed LNG storage tank in 2010 by Soil Mechanics. Borehole logs indicate that the upper most sections of alluvial deposits have been truncated, likely by the construction of the mid-20th century Kent Oil Refinery and capped with redeposited gravels and clays. Peat lenses within the alluvial deposits were recorded in BH1B (between 3.1m to 5.5mbgl and BH2 (2.4m to 6.0mbgl). Rare to frequent pockets of organic material were encountered in all the boreholes which extended into the alluvium (BH1B: 1.7m to 3.1mbgl; BH2: 2.4m to 3.0mbgl and 5.0mbgl; BH3: 2.5m to 3.0mgbl; and BH4: 4.7mbgl and 6.6m to 7.2mbgl). 5.2.3 One historic borehole has also been conducted within the eastern corner of the construction laydown area (TQ87NE43). The date of the borehole was not recorded and information regarding the upper levels ground deposits is limited. Ground level of the borehole was 5.1m OD and London Clay was reached at 5.5mbgl, the depths and thicknesses of the overlying made ground, alluvium and gravels were not recorded. 5.2.4 The closest past investigations to the Phase 3B area and construction laydown are two watching briefs 140m south of the southern boundary of the construction laydown area (DBA 2 and 3). DBA2, conducted by Archaeology South East in 2007 at the Isle of Grain Power Station, revealed 0.8m of made ground overlying 0.9m of alluvium, below which were gravels. 5.2.5 DBA3, conducted by MoLAS on Grain Road in 2003, involved monitoring three test pits on the north-west side of Grain Road where ground level was 1.3m OD. The earliest deposit in these tests was Gravel which was encountered at 1.0mbgl (0.3m OD) overlain by alluvium with a maximum thickness of 0.7m (to 1.0m OD). This was capped by 0.3m of peat to the approximate ground level. These pits were contaminated with asbestos and other unknown substances. A further 10 test pits were monitored on the south-east side of Grain Road where the ground level was recorded as 2.2m OD. Three of the tests were comprised entirely of modern made ground, the deposits having been truncated for services. Four additional test pits were only excavated to 0.9mbgl. Alluvium was encountered at 0.7mbgl (1.2m OD) below made ground. The remaining test pits monitored encountered Gravels at 1mbgl (1.2m OD) overlain by 0.6m of alluvium and 0.4m of made ground. The peat encountered was not obviously woody, which is characteristic of prehistoric material, and there was a sharp contact with the underlying alluvium though close examination was not possible due heavy hydrocarbon contamination. The view of the MoLAS Geoarchaeologist is that, when these characteristics are considered in conjunction with the elevation of the deposit, the material is likely to represent the deposition of ‘fen’ peat in the historic period. Recently, ‘late’ (c. 700 BP) peats in the Chatham area have been noted at an elevation of c 0.00 m OD, whereas prehistoric peats
Archaeological Desk Based Assessment © MOLA 2020 14 Grain LNG Phase 3B3B 09/12/2020 on the Medway Tunnel Approach at Chatham were noted at depths of between –9.5m and – 8.0m OD for Mesolithic deposition, while peats between –3.3m and –4.4m OD were likely to be of Neolithic/Bronze Age date. It is possible that the peat may have formed in localised pooling rather than as a widespread deposit given its absence to the south-east. 5.2.6 At the location of earlier LNG storage tanks, 560m west of the western boundary of the Phase 3B area, nine test piles were monitored by MoLAS in 2005, and revealed a sequence of alluvial clays overlain by a thin layer of peat and capped by modern concrete structures and vegetation (DBA 7). The former were deposited under conditions of lower and higher mean sea levels (marine regressions and transgressions). These deposits were probably laid down in the prehistoric period from approximately 12,000 years ago to the historic period. The alluvial clays were observed approximately at a height of between –17.6m to –2.6m OD. A peat horizon, which survived to a height of 2.4m OD, was the latest deposit and was probably formed in the historic period. This sequence of alluvial clays and peats is of limited palaeoenvironmental significance (MoLAS 2005), and is likely to represent the deposition of ‘fen’ peat in the historic period, as discussed above. It is likely that a similar sequence lies on the site. 5.2.7 Work undertaken by Bates (1999), at Kingsnorth Power Station site c 6.7km south-west of the Phase 3B area, identified three previously recorded gravel terraces at the Isle of Grain, a High terrace, Intermediate terrace, and a Low terrace. The general consensus suggests that the High terrace is likely to the oldest and the Low terrace is the youngest, dating to the final episode of the Devensian cold period (post–20,000yrs BP) and equated to the Shepperton gravels. If correct the Intermediate and High terraces may be of early Devensian or earlier date (equivalent to the East Tilbury Marshes terrace). 5.2.8 Table 1 differentiates between modern made ground (i.e. containing identifiably modern inclusions such as concrete and plastic) and undated made ground, which may potentially contain deposits of archaeological interest. This distinction was not apparent in the original report as it was commissioned for engineering purposes. In all likelihood, the undated made ground also dates to the modern period when the site was developed.
Table 1: summary of geotechnical data (ref Soil Mechanics 2010 and BGS 2020) Levels are in metres below ground level (mbgl)
BH/TP ref. Ground Modern Undated Natural Natural Top of level m OD made ground made ground alluvium Gravels natural clay BH1 3.1 <1.3 *test - - - - terminated due to obstruction BH1A 3.1 <1.3 *test - - - - terminated due to obstruction BH1B 2.5 <1.7 - 1.7–6.8 6.8– 11.7 11.7 BH2 2.5 <1.5 - 1.5–6.4 6.4– 11.1 11.1 BH3 2.4 <1.0 - 1.0–9.5 9.5– 10.2 10.2 BH4 3.1 <1.0 1.0–1.2 1.2–7.2 7.2– 11.1 11.1 TQ87NE43 5.1 <5.5 (BH5)
5.2.9 Based on the limited topographic survey and previous investigations and an historic borehole the ground levels of the Phase 3B area and laydown are assumed to be between 2.3m and 5.1m OD, rising to the south and east, the variation across the site is likely the result of ground consolidation and truncation. The geotechnical data suggests that the top of truncated alluvium at between 1.0m to 1.7mbgl (truncation is possibly deeper in some parts based on obstructions encountered); peat deposits will be encountered in the upper levels of the alluvial deposit. The
Archaeological Desk Based Assessment © MOLA 2020 15 Grain LNG Phase 3B3B 09/12/2020 alluvium is expected to be up to 8.5m thick in parts. Below which are gravels at between 6.4– 9.5mbl. The entire area appears to be artificially levelled, with areas covered by hard standing, paved roads and temporary modern buildings.
Past impacts 5.2.10 Due to the areas rural setting and long-established agricultural use it is unlikely that any major truncation impacts were incurred prior to the mid-20th, except possibly the construction of Hook’s Wall embankment along the southern extent of the construction laydown which may date back to the medieval period. The excavation of drainage ditches may have created shallow truncations along localised transects. These may have partially or totally damaged archaeological assets within their footprint however the ditch cuts are unlikely to have penetrating deep into archaeological strata. The embankment would have required extensive quarrying for ballast material. Neither the Tithe map nor 1st edition Ordnance Survey map provides evidence of nearby quarrying. It is more likely that material was imported from the gravel island east/north-east of the site or from further afield. Alternatively, as these embankments may actually be of medieval origin it may be that quarrying had taken place within the site area or vicinity earlier but evidence of pitting had been infilled by the time of detailed cartography in the late 19th century. If quarrying had taken place within the site, it would have truncating any earlier remains within its footprint. 5.2.11 Major localised disturbances were made during the construction works of the Kent Oil Refinery (Anglo-Iranian Oil Company Ltd.) in the mid-1950s. The construction of a tarmac/ metalled road surface, which sections off the site, would have required ground stripping and bedding material laid to ensure the road could cope with the possible heavy traffic and/or plant expected while the refinery was in use. The construction of tanks and buildings on the site likely would have required ground levelling and some foundations. Given that the site sits on possible alluvium it is likely that these foundations are relatively deep and would have removed any remains of archaeological interest within its footprint. 5.2.12 The Phase 3B area was used a laydown yard during construction of the adjacent LNG storage tank immediately west of the site (Kent County Council, Heritage Maps, 2008 aerial photography). All above ground structures and equipment associated with the old oil refinery or historical site works having been cleared; however the majority of below ground foundations likely remain in-situ, as with other areas of the previous refinery and suggested by the obstructions encountered during the geotechnical survey. Some parts of the Phase 3B area and laydown were covered with hardstanding, at least a portion of the section of the site south of the proposed LNG storage tank location and part of the construction laydown area to the east. The easternmost hardstanding survives, while most of the other area of hardstanding has been removed, except for an access road and seven parking spots. Numerous temporary buildings were also constructed on the site, most of which have since been removed. 5.2.13 The Phase 3B area and construction laydown is currently brownfield land, except for the hardstanding and temporary buildings which surviving as outlined above. The roadways through the area are also still present and probably actively used. The edge of the south-west corner of the area is overlapped by the route of an above ground pipeline leading from the constructed LNG storage tank to the south-east. 5.2.14 Any leaching of chemical substances such as petroleum oil during the operation of the refinery may have contaminated the upper-most alluvial deposits and subsequently reduced the significance of any potential geoarchaeological remains within the path of contamination to negligible.
Likely depth and thickness of archaeological remains 5.2.15 Any archaeological remains present would be expected within remaining alluvial deposits beneath made ground at 1.0–1.7mbgl, depending on the severity of past truncating impacts. Available geotechnical data suggests that remaining alluvium would measure 4.9–8.5m thick. However, within the localised footprints of palaeochannels alluvium may extend further. 5.2.16 Any evidence of early prehistoric (Upper Palaeolithic/Early Mesolithic) activity would be located at the alluvium/gravel interface and cut into the underlying gravel at c 6.4m to–9.5m OD. Later prehistoric, Roman, and later remains would be located progressively higher up in the alluvial sequence. Post-medieval deposits/features potentially survive directly below any modern
Archaeological Desk Based Assessment © MOLA 2020 16 Grain LNG Phase 3B3B 09/12/2020 made ground, depending on the severity of past truncations. Alluvial deposits within former palaeochannels may contain later prehistoric, Roman and later remains as earlier sediments may have been washed away by the currents. The location of palaeochannels may be assumed by examination of the study areas topography and gradient, however it likely that the position of palaeochannels altered over time.
5.3 Archaeological potential, and significance of likely remains
5.3.1 The nature of possible archaeological survival in the area of the development is summarised here, taking into account the levels of natural geology and the level and nature of later disturbance and truncation discussed above.
Statement of Significance 5.3.2 The Phase 3B area has high potential for encountering palaeoenvironmental remains. The Phase 3B area is located within the reclaimed marshland that would have once been intertidal marshes comprised of silty clay alluvial deposits overlying sloping gravels, which are gradually eroded away towards the course of the present-day River Medway. Palaeochannels would have cut deep through the marshland clays and underlying natural gravels, resulting in localised areas of deep alluvial sequences, potentially with lenses of peat deposits. These palaeochannels were likely subject to frequent flooding episodes that may have led to earlier deposits being washed away. Minerogenic deposits such as alluvial silts and clays have the potential for preservation of diatoms that can provide information on the salinity status of the depositional environments that would enhance interpretation of the sedimentary sequence. Organic remains, such as peat, are likely to contain microfossils (e.g. pollen) and floral and faunal macrofossils such as molluscs and occasionally ostracods, seeds, plant fragments and pollen which can be utilised to reconstruct past local environments, provide indirect evidence of local human activity and useful data to assist our understanding of past sea level changes. Additionally, peat, if present, may contain late prehistoric timber remains of trackways or platforms. Wood and organic sediment can be dated by radiocarbon, to establish the chronology of the sequence. Lenses of peat and/or organic material were recorded in the alluvial deposits collected during the geotechnical investigation of the location of the LNG storage tank. However, any leaching of chemical substances such as petroleum oil during the operation of the refinery may have contaminated the upper-most alluvial deposits and subsequently reduced the significance of any potential geoarchaeological remains within the localised path of contamination to negligible. The significance of such remains is low, unless deposits of peat or other datable material is present, which would be of medium significance, based on their likely archaeological and historic value in providing evidence of past environments and human activity at a local and wider regional scale. 5.3.3 The Phase 3B area has a low to moderate potential for encountering prehistoric remains. The site is located within the intertidal marshland area. This area would have been subject to flooding and the geology would not have conducive to habitation unlike the gravel outcrop on higher ground to the east and north-east of the site (Britannia XIII, 1982, 393–395). However, resource exploitation activities such as fishing, fowling, and grazing would have taken place. There is low potential for remains of associated structures such as platforms, bridge piers, jetties, and fish traps which may have been constructed. The ephemeral nature of these activities suggests that little tangible and/or visible evidence may remain. There is moderate potential for undisturbed alluvial deposits within the site which could contain evidence of successive episodes of prehistoric activity. Prehistoric remains may be present at deeper levels in the alluvium than later remains, however, due to the truncating impacts of the Kent Oil Refinery, particularly deep made-ground redeposits and the excavation of the access road. The significance of the any prehistoric remains would depend on their nature and extent. Extensive and well-preserved features may be of low to medium significance, depending on their evidential and historical value. Isolated and/or residual artefacts would likely be of low significance. 5.3.4 The Phase 3B area has a low potential to contain Roman, medieval and post-medieval remains. The Phase 3B area was located in low-lying marshland prone to flooding with settlement focused on the higher, elevated gravel island nearby to the north-east. Cartographic evidence suggests that, apart from ‘Hook’s Wall’ which overlaps the southern boundary of the
Archaeological Desk Based Assessment © MOLA 2020 17 Grain LNG Phase 3B3B 09/12/2020 site, the site was not built upon until the expansion of the Kent Oil Refinery in the mid-1950s. Pastoral agricultural activity in the later medieval and post-medieval periods, including the construction of drainage ditches; grazing leaves little visible traces and the drainage ditches were likely shallow cut features that may have been removed or infilled following extensive levelling and clearing activities prior to the construction of the 20th century refinery.
Archaeological Desk Based Assessment © MOLA 2020 18 Grain LNG Phase 3B3B 09/12/2020 6 Impact of proposals
6.1 Proposals
6.1.1 Phase 3B comprises the construction of the following elements as previously approved as part of Phase 3 under permission Ref: MC2007/1683: construction of one LNG storage tank; installation of three submerged combustion vaporisers; and provision of related infrastructure. 6.1.2 The LNG storage tank will be built east of the existing LNG storage tank, which was also previously approved as part of Phase 3 (Fig 9), and on existing hardstanding. As with previously built LNG storage tanks, the base of the tank will be formed of a concrete base slab supported by concentric rings of 800mm diameter piles. Taking into account the ground conditions and the load exerted by the tanks, it is estimated that 700 piles, each to a depth of approximately 37m below finished ground level, will be required to support the tank base. The slab diameter of the tank will be approximately 94.8m and the tank will stand approximately 50.1m high. 6.1.3 Vaporisers and other minor infrastructure foundation depth is likely to be minimal, and the footings for these are already in place. The ancillary infrastructure associated with the tank consists of wall and roof platforms, ladders, walkways and handrails, internal and external pipes and fitting, internal tank pumps and other necessary electrical and instrumental equipment. A temporary laydown area for the construction phase of the LNG storage tank and associated plant is to be situated east of the tank location. 6.1.4 If levelling of the land is required for the development, it is assumed a ‘cut and fill’ exercise could be carried out. This would utilise material that is above the required final land levels as infill for those area that need raising up, subject to the material being suitable (deemed non- hazardous).
6.2 Implications
6.2.1 The identification of physical impacts on buried heritage assets within a site takes into account any activity which would entail ground disturbance, for example site set up works, remediation, landscaping and the construction of new foundations. As it is assumed that the operational (completed development) phase would not entail any ground disturbance there would be no additional archaeological impact and this is not considered further. 6.2.2 It is outside the scope of this archaeological report to consider the impact of the development on upstanding structures of historic interest, in the form of physical impacts which would remove, alter, or otherwise change the building fabric, or predicted changes to the historic character and setting of historic buildings and structures within the site or outside it.
Site preparation, ground breaking and obstruction removal 6.2.3 Works carried out as part of the initial site set up, including preliminary site stripping and demolition, the installation of site fencing and welfare facilities, is assumed for the purposes of this assessment to cause localised ground disturbances to a maximum depth of 0.5mbgl. This would extend into modern made ground only have no archaeological impact. 6.2.4 The impact of obstruction removal would depend on the size and depth of existing obstructions. Boreholes BH1 and BH1A were both terminated at 1.3mbgl due to an obstruction. Any removal excavations that exceed the depth and/or dimensions of installation excavations (see below) would truncate adjacent alluvium remains and entirely remove any archaeological remains within their footprint.
Vaporisers and other minor infrastructure foundations 6.2.5 The foundations for the vaporisers and other auxiliary buildings are already in place and are assumed for the purposes of this assessment to be similar to standard shallow foundations, i.e. strip and pad/raft foundations. Such foundations are assumed to extend to a depth of c 1.5m below ground level and would affect only the upper levels of surviving alluvium;
Archaeological Desk Based Assessment © MOLA 2020 19 Grain LNG Phase 3B3B 09/12/2020 truncating only post-medieval agricultural remains.
Piling 6.2.6 Any archaeological remains within the footprint of each pile would be removed as the pile is driven downwards. The severity of the impact would therefore depend on the pile size, type and pile density. Where the piling layout is particularly dense, it is in effect likely to make any surviving archaeological remains, potentially preserved between each pile, inaccessible in terms of future archaeological investigation. 6.2.7 Continuous flight auger (CFA) piles are proposed and would minimise the impact upon possible archaeological remains whereas vibro-compacted piles may cause additional impact through vibration and deformation of fragile surrounding remains, in particular at the level of the water table. 6.2.8 The insertion of pile caps and connecting ground beams, along with the excavation of a pile guide trench, typically extend no more than 1.0–1.5mbgl, would remove or truncate any archaeological remains within the footprint of these works to this depth, impacting made ground and alluvial deposits.
Archaeological Desk Based Assessment © MOLA 2020 20 Grain LNG Phase 3B3B 09/12/2020 7 Conclusion and recommendations
7.1.1 The Phase 3B area does not contain any nationally designated (protected) heritage assets, such as scheduled monuments, listed buildings or registered parks and gardens. Nor is the site located within an APA or conservation area. 7.1.2 The findings of this desk-based assessment are consistent with past assessments of the Phase 3B development area as included in the 2006 Grain LNG Phase 3 Expansion Environmental Statement (Planning Ref: MC2006/1428) and the 2007 Grain LNG Expansion Project Northern Zone Update (Planning Ref: MC2007/1683). 7.1.3 The Phase 3B area and laydown has high archaeological survival for palaeoenvironmental remains as recorded during a geotechnical investigation of part of the site in 2010. Any earlier remains are likely to have been removed during major past truncations on the site including ground consolidation, levelling and construction related to industry development between the mid-20th century and present. 7.1.4 The main impact from the scheme will be the piled foundation of the LNG storage tank base, which would remove archaeological/palaeoenvironmental remains within the footprint of each pile. Other site works, including obstruction removal, below ground vaporisers and other minor foundations, may also impact the upper levels of surviving alluvium deposits. 7.1.5 Table 2 summarises the known or likely buried assets within the Phase 3B area and laydown, their significance, and the impact of the scheme on asset significance.
Table 2: Impact upon heritage assets (prior to mitigation) Asset Asset Impact of proposed scheme Significance Palaeoenvironmental evidence within alluvial Low to Medium Piled foundations deposits (High potential) Overall significance reduced to Prehistoric evidence of activity in alluvial Low to Medium negligible deposits (Moderate potential) and remains of marshland/intertidal zone exploitation (i.e. Obstruction removal; construction trackways, jetties, fish traps; Low potential) of buried vaporisers and minor foundations
Significance of the asset would be reduced to negligible within the impacted areas.
7.1.6 Although the proposed development has high potential to contain palaeoenvironmental evidence of low to medium significance and low to moderate potential to contain prehistoric remains of low to medium significance, in light of the localised area of the proposed impact, it is unlikely that the local authority would require further preliminary site-specific archaeological evaluation. It is likely, however, that given the uncertainty of site-specific geological remains archaeological monitoring of intrusive works (below ground) would be requested in order to confirm the precise level of natural deposits along with presence and depth of any archaeological remains. The previously proposed mitigation of a watching brief, as recommended during the 2006 and 2007 assessments, remains appropriate. 7.1.7 Any archaeological work would need to be undertaken in accordance with an approved Written Scheme of Investigation (WSI) and be carried out under the terms of Discharge of Condition 27 as set out in decision notice MC/07/1683.
Archaeological Desk Based Assessment © MOLA 2020 21 Grain LNG Phase 3B3B 09/12/2020 8 Gazetteer of known historic environment assets
8.1.1 The gazetteer lists known historic environment sites and finds within the 1km-radius study area around the site. The gazetteer should be read in conjunction with Fig 2. Note: as DBA 1a covers the entire site and study area it is not included in Fig 2 for clarity. 8.1.2 The KHER data contained within this gazetteer was obtained on 15/10/2020 and is the copyright of Kent County Council 2020. 8.1.3 Ordnance Survey data © Crown copyright and database right 2020. Historic England statutory designations data © Historic England 2020. The Historic England GIS Data contained in this material was obtained in November 2019. The most publicly available up to date Historic England GIS Data can be obtained from http://www.historicengland.org.uk.
Abbreviations ASE – Archaeology South East CAT – Canterbury Archaeological Trust DGLA – Department of Greater London Archaeology (Museum of London) EH – English Heritage (now Historic England) EKE – KHER unique event identifier EWX – KHER unique event identifier HA – Headland Archaeology HER – Historic Environment Record MKE – KHER unique monument identifier MoLAS – Museum of London Archaeology Service (now MOLA) MWX – KHER unique monument identifier NHL – National Heritage List for England (Historic England) WA – Wessex Archaeology
DBA Description Site code/ No. HER/NHL No. 1a Hoo Peninsula, Kent EWX8090 Walkover Survey, WA, 2001 A walkover or fieldwalking survey was conducted across the extent of the Isle of Grain as part of the North Kent Coast Rapid Coastal Zone Assessment Survey (RCZAS). No further information regarding this investigation is currently available.
Walkover Survey, ASE, 2004 EKE8888 A walkover or fieldwalking survey was undertaken at the installation site of a proposed new plant to ‘re-power’ the existing units at the Grain Power Station. No archaeological features or residual artefacts were recorded.
Historic Landscape Assessment, EH, 2009–2012 EKE15020; An aerial photographic and Lidar mapping assessment was undertaken across the EKE15021 whole of the peninsula and included features in the intertidal zone. The work used National Mapping Programme methods and systematically examined a wide range of aerial photographs dating from the 1940s to the 2000s. The aerial photographic work recorded archaeological features with a date range from prehistory to the modern era including buried remains visible as cropmarks, and surface remains seen as earthworks and structures, the latter mainly relating to 20th-century military remains. The features visible on the photographs were accurately transcribed and the details recorded in English Heritage's National Record of the Historic Environment (NRHE). A series of aerial reconnaissance flights over the peninsula, undertaken as part of the project, revealed further previously unknown sites and provided general views of the landscape, villages, architectural and inter-tidal remains.
Archaeological Desk Based Assessment © MOLA 2020 22 Grain LNG Phase 3B3B 09/12/2020 DBA Description Site code/ No. HER/NHL No. 1b Two Anglo Saxon Sceattas, Isle of Grain MKE3177 A metal detector encountered two Anglo-Saxon coins in 1984, ‘under an old wall’ and MKE3186 on the gravel island. Both coins were silver sceattas, however one coin was a London MKE76591 derived series, diademed bust to the right and a cup in front. On the reverse side is an image of a king standing with head turned to the right holding a cross in one hand and a bird in the other; however the identity of the king displayed, the mint and the moneyer are uncertain. The other coin is a ‘Kentish’ type dated to circa. 690–725.
Site of 16th Century Beacon, Isle of Grain MKE3177 Cartographic evidence, William Lambarde’s ‘Carde’ of c. 1570 illustrates the position of coastal beacon sites, totalling 52 sites across Kent. The beacon system dropped out of use as communication system after 1640. No further information is available about the survival of a 16th century beacon located within the vicinity.
Crash Site of Heinkel He 111H-2 MKE89757 The KHER note that within this approximate location a Luftwaffe Heinkel He 111H-2 bomber aircraft crashed on 7th September 1940 and was burnt out by the surviving crew. The crew were subsequently captured and detained by British military authorities 2 Grain Power Station, Isle of Grain EKE12631 Watching Brief, ASE, 2007 Archaeological monitoring of groundworks associated with the removal of contaminated soils and deep drilling observed no archaeological finds or features. 3 Grain Road, Isle of Grain EKE16407 Watching Brief, MoLAS, 2003 KT-IOG03 Archaeological monitoring of 13 geotechnical test pits, each 1m square and extending 0.9mbgl, revealed no archaeological features however deposits of ‘local significance’, likely alluvial deposits, were encountered. 4 Grain to Shrone/ Gravesend Gas Pipeline, Isle of Grain EKE17316 Field-walking Survey, CAT, 2006 A programme of field-walking was undertaken along the route of the proposed pipeline. No detailed information is currently available.
Geophysical Survey, Stratascan, 2006 EKE17318 Stratascan undertook a magnetic geophysical investigation on behalf of Canterbury Archaeological Trust. Fourteen scattered responses were detected, however none of these appeared to follow a coherent pattern and it is believed that they represent geological or pedological anomalies rather than evidence of archaeological activity. 5 B2001 Culvert, Isle of Grain EKE9729 Watching Brief, SecondSite, 2004 Archaeological watching brief undertaken during the construction of a new pipeline that ran through the existing B2001 culvert recorded no archaeological features. Ground contamination was observed, specifically a concentration of hydro-carbons. Gravel layers appeared intact, which may suggest potential for prehistoric remains. 6 Grain LNG Second Cryogenic Pipeline, Isle of Grain EKE10128 Geotechnical Survey, Atkins, 2007 Boreholes and test pits were dug along the route of a proposed pipeline. 7 Additional LNG Storage Tanks, Grain LNG, Isle of Grain EKE9724 Watching Brief, MoLAS, 2005 During a watching brief undertaken prior to the sites further development no archaeological remains or features were identified.
Archaeological Desk Based Assessment © MOLA 2020 23 Grain LNG Phase 3B3B 09/12/2020 DBA Description Site code/ No. HER/NHL No. 8 Proposed Windfarm, Wallend, Isle of Grain EKE15641 Geoarchaeological Survey, HA, 2007 The investigation recorded a potential sequence of Pleistocene and Holocene sediments however no definite dating evidence, ecofacts or artefacts were identified. The site investigation has provided a model for sequence development that spans a considerable period of time. The history of sedimentation has varied from cold climate to temperate and a range of different environments of deposition are represented. At present age estimates are based on previous work which is based on limited surveys and inadequate data sets. Many of the sediment bodies or environments of deposition have not been identified previously for the Medway region and consequently it is important to verify the conclusions drawn in this study through the recovery of samples for palaeoenvironmental assessment and dating. Indeed some of these contexts of deposition may represent ideal situations for past human exploitation (e.g. high energy beach environments, back beach situations) and in others ideal situations for sequence preservation (i.e. those areas buried by cliff collapse and erosion perhaps indicated in BH 6). Given this current level of uncertainty about the nature and potential of the deposits and the predicted impact of piling on these deposits. 9 Crash site of Dornier Do17Z-3 MKE89755 A World War II Luftwaffe light bomber aircraft. 10 Hoo Junction and Port Victoria Railway MKE44047 Single track railway from Hoo Junction on the North Kent Line to Port Victoria on the Isle of Grain. Passengers alighting at Port Victoria caught a ferry across to Queensborough to connect with the Dutch Steamers. The line opened in 1882 but never flourished. The ferry ceased to operate in 1901 and in 1916 Port Victoria pier was closed due to decay. Despite a double track branch line to Allhallows opening in 1932, the attempt to turn Allhallows into an attractive resort failed and the branch line closed in 1961. The opening of the Isle of the Grain oil refinery in 1951 gave the line a new lease of life, and it continues to transport oil to and from the refinery. 11 Early Medieval copper alloy buckle MKE71855 A large cast copper-alloy D-shaped buckle, thought to be of late Anglo-Saxon date (900–1100), was found by a metal detectorist under the Portable Antiquities Scheme. The artefact was complete and in good preservation. The buckle face had an intricate decoration depicting ‘biting beasts’. A decorated pin rests in a square housing on the frame that has a zoomorphic knob. The frame of the buckle is fashioned like the segmented or furry necks of two dragons or other beasts; their jaws grip the bar around which the strap fitted. The buckle was 45mm long and 40mm wide. 12 Home Farm, Wallend, Isle of Grain MKE83394 A 19th century courtyard with working agricultural buildings on one side and with additional detached elements to the main plan was recorded by the Hoo Peninsula, Isle of Grain Historic Area Assessment undertaken by English Heritage in 2014. The structure was completely destroyed following 20th century development on the site. 13 Farmstead, Wallend, Isle of Grain MKE83391 A 19th century detached farmhouse with ancillary structures was recorded by Isle of Grain Historic Area Assessment conducted by English Heritage in 2014. The farmsteads lay outside of the Grain village area and the report notes that: ‘By the 18th century, if not earlier, much of the farming was done by tenants for absent owners… In the 1840s only two properties, White House Farm and Whitehall Farm, were farmed by their owners’. The farmhouse and curtilage has been completely destroyed following 20th century development on the site. 14 Farmstead, Wallend, Isle of Grain The Kent farmsteads and landscape project undertaken by Forum Heritage Services in MKE83392 2012 recorded a loose farmstead cluster which was completely demolished, likely for the construction of the Medway Power Station. 15 Outfarm, Wallend, Isle of Grain A field barn with no associated yard was recorded by the Kent Farmsteads and MKE83393 Landscape Project, undertaken by Forum Heritage Services in 2012. The structure was completely destroyed following 20th century development on the site. 16 1st/2nd Upchurch flask, near Wallend Farm, Isle of Grain MKE3173 A 1st or early 2nd century cordoned flask vessel of Upchurch ware. Found in 1951 near Wallend Farm during excavations for the Anglo Iranian Oil Company.
Archaeological Desk Based Assessment © MOLA 2020 24 Grain LNG Phase 3B3B 09/12/2020 DBA Description Site code/ No. HER/NHL No. 17 Site of a 13th century midden, near Wallend, Isle of Grain MKE3175 A small medieval kitchen midden was found in 1950 on the eastern bank of a large borrow pit. The c. 2m by 2m hollow feature contained hundreds of oyster, whelk and cockle shells, with ox and sheep bones and four sherds of a jug dated to the 13th century. 18 Site of salt-pans, windpump and buildings, near Newlands MKE3172 A group of about 10 salt-pans, with a wind-pump and three buildings is shown on Hasted’s map of 1782 and shown on later historic maps as ‘Old Salt Works’. 19 Redhouse Farm, Isle of Grain MKE83388 Mentioned in Isle of Grain Historic Area Assessment conducted by English Heritage in 2014 as a loose courtyard plan farmstead with buildings to two sides of the yard and part of a group of farms located in the marshes on the Isle of Grain. 20 Wilford’s Farm, Isle of Grain MKE83400 An 18th century or earlier loose courtyard plan farmstead with building to two sides of the yard was recorded in the Isle of Grain Historic Area Assessment conducted by English Heritage in 2014. Described as part of a group of farms outlying in the countryside around the village of Grain. 21 Grain Crossing Signal Box, Isle of Grain NHL1415162 Grain Crossing Signal Box, an 1882 signal box built for the South Eastern Railway by contractors Stevens & Sons, is designated at Grade II because it is the only surviving example in the country of a Stevens & Sons signal box. Unusually it is single storeyed above ground, the timber frame clad in Stevens & Sons trademark vertical boards with the joints covered by battens, but the locking room is below ground. The structure is externally intact except that the windows were replaced in the later 20th century. Moreover, it retains an operational South Eastern Railway lever frame of 9 levers, and a cast iron token machine.
The KHER note that a railway station was present at this location and marked on 2nd, MKE8342 3rd and 4th edition Ordnance Survey maps, from 1891–1940. The station formed part MKE8365 of the Hoo Hundred Railway Line and was completed in 1892, however passenger services ended in 1961. A level crossing was also present here from the inception of the station and was still visible from aerial photography taken in 2000. 22 Disused oil refinery railway station, Isle of Grain MKE98874 The Isle of grain Historic Area Assessment, undertaken by English Heritage in 2014, noted a disused railway station, constructed by British Petroleum to service the nearby oil refinery, still extant. Evidence of the station came from aerial photography from 1960-2015. 23 Enclosure near Old Salt Works, near Yantlet Creek, Isle of Grain MWX18147 A rectangular enclosure marked on historic Ordnance Survey maps (c. 1858-1940) near the site of an ‘Old Salt Works’. It was also identified from aerial photographs taken shortly after the end of World War II. 24 Military Installation, Isle of Grain MWX18161 Military installation identified from aerial photographs taken after the end of World War II. Located near Grain Power Station, present condition unknown. 25 Unidentified feature, near Wallend, Isle of Grain MWX18481 An unidentified feature was noted on aerial photographs taken in 1942. No further information relating to this record is currently available. 26 Wallend, Isle of Grain MWX17253; A Cordoned Flask was unearthed by workmen during construction works on the Isle of MKE71909; Grain in 1951. The flask was dated to the 1st to early 2nd centuries AD. Iron Age MKE71910 coinage was also encountered within the vicinity comprising two gold quarter stater coins, weighing approximately 1.3 grams. 27 Grain Marshes, Isle of Grain MKE3216 The remains of a suspected pottery kiln were discovered during excavations by workmen in 1939 in the Grain Marshes at 0.9–1.2m OD. The finds included thin kiln bricks and a mixture of Roman and medieval sherds, as well as the handle of a large jug. No subsequent archaeological investigations have been undertaken here.
Archaeological Desk Based Assessment © MOLA 2020 25 Grain LNG Phase 3B3B 09/12/2020 DBA Description Site code/ No. HER/NHL No. 28 Site of Wallend Petroleum Tank Farm, Isle of Grain MWX17261 Ground work undertaken by workmen in the early 20th century unearthed possible Iron Age/ Roman archaeological remains. Workers reported a seam of burnt clay with burnt brick and one ceramic pottery sherd. Mr. E. Greenfield argued that the sherd was an Iron Age South-Eastern B type, probably from an omphalos bowl with tooled semicircles of impressed concentric rings. Inspection by Mr. J. Evans in 1950 suggested that archaeological deposits here may have been 1.4m thick, extending to 7.1m OD. 29 Cropmark of ring ditch to the west of Grain MKE77362 A ring ditch visible as a cropmark in aerial photos of 1990 to the west of Grain. It is 22m x 20m and consists of a single ring with no interruption. 30 Cropmark of ring ditch to the west of Grain MKE91138 A ring ditch visible as a cropmark in a Google Earth image of 2013. It is 19m x 19m and consists of a single circular ditch with one interruption by the road. 31 Cropmark of ring ditch to the west of Grain MKE91139 A ring ditch visible as a cropmark in a Google Earth image of 2013. It is 11m x 11m and consists of a single circular ditch.
Archaeological Desk Based Assessment © MOLA 2020 26 Grain LNG Phase 3B3B 09/12/2020 9 Planning framework
9.1 National Planning Policy Framework
9.1.1 The Government issued the National Planning Policy Framework (NPPF) in March 2012 (DCLG 2012) and supporting Planning Practice Guidance in 2014 (DCLG 2014). The 2012 NPPF was revised and a new NPPF published in July 2018, with minor revisions in February 2019 (MHCLG 2019).
Conserving and enhancing the historic environment 9.1.2 The NPPF section concerning “Conserving and enhancing the historic environment” (section 12 of the NPPF 2012) has been replaced by NPPF 2018 Section 16 (unchanged in February 2019), reproduced in full below: Para 184. Heritage assets range from sites and buildings of local historic value to those of the highest significance, such as World Heritage Sites which are internationally recognised to be of Outstanding Universal Value. These assets are an irreplaceable resource, and should be conserved in a manner appropriate to their significance, so that they can be enjoyed for their contribution to the quality of life of existing and future generations. Para 185. Plans should set out a positive strategy for the conservation and enjoyment of the historic environment, including heritage assets most at risk through neglect, decay or other threats. This strategy should take into account: • a) the desirability of sustaining and enhancing the significance of heritage assets, and putting them to viable uses consistent with their conservation; • b) the wider social, cultural, economic and environmental benefits that conservation of the historic environment can bring; • c) the desirability of new development making a positive contribution to local character and distinctiveness; and • d) opportunities to draw on the contribution made by the historic environment to the character of a place. Para 186. When considering the designation of conservation areas, local planning authorities should ensure that an area justifies such status because of its special architectural or historic interest, and that the concept of conservation is not devalued through the designation of areas that lack special interest. Para 187. Local planning authorities should maintain or have access to a historic environment record. This should contain up-to-date evidence about the historic environment in their area and be used to: • a) assess the significance of heritage assets and the contribution they make to their environment; and • b) predict the likelihood that currently unidentified heritage assets, particularly sites of historic and archaeological interest, will be discovered in the future. Para 188. Local planning authorities should make information about the historic environment, gathered as part of policy-making or development management, publicly accessible.
Proposals affecting heritage assets Para 189. In determining applications, local planning authorities should require an applicant to describe the significance of any heritage assets affected, including any contribution made by their setting. The level of detail should be proportionate to the assets’ importance and no more than is sufficient to understand the potential impact of the proposal on their significance. As a minimum the relevant historic environment record should have been consulted and the heritage assets assessed using appropriate expertise where necessary. Where a site on which development is proposed includes, or has the potential to include, heritage assets with archaeological interest, local planning authorities should require developers to submit an appropriate desk-based assessment and, where necessary, a field evaluation. Para 190. Local planning authorities should identify and assess the particular significance of any heritage asset that may be affected by a proposal (including by development affecting the setting of a heritage asset) taking account of the available evidence and any necessary
Archaeological Desk Based Assessment © MOLA 2020 27 Grain LNG Phase 3B3B 09/12/2020 expertise. They should take this into account when considering the impact of a proposal on a heritage asset, to avoid or minimise any conflict between the heritage asset’s conservation and any aspect of the proposal. Para 191. Where there is evidence of deliberate neglect of, or damage to, a heritage asset, the deteriorated state of the heritage asset should not be taken into account in any decision. Para 192. In determining applications, local planning authorities should take account of: • a) the desirability of sustaining and enhancing the significance of heritage assets and putting them to viable uses consistent with their conservation; • b) the positive contribution that conservation of heritage assets can make to sustainable communities including their economic vitality; and • c) the desirability of new development making a positive contribution to local character and distinctiveness.
Considering potential impacts Para 193. When considering the impact of a proposed development on the significance of a designated heritage asset, great weight should be given to the asset’s conservation (and the more important the asset, the greater the weight should be). This is irrespective of whether any potential harm amounts to substantial harm, total loss or less than substantial harm to its significance. Para 194. Any harm to, or loss of, the significance of a designated heritage asset (from its alteration or destruction, or from development within its setting), should require clear and convincing justification. Substantial harm to or loss of: • a) grade II listed buildings, or grade II registered parks or gardens, should be exceptional; • b) assets of the highest significance, notably scheduled monuments, protected wreck sites, registered battlefields, grade I and II* listed buildings, grade I and II* registered parks and gardens, and World Heritage Sites, should be wholly exceptional. Para 195. Where a proposed development will lead to substantial harm to (or total loss of significance of) a designated heritage asset, local planning authorities should refuse consent, unless it can be demonstrated that the substantial harm or total loss is necessary to achieve substantial public benefits that outweigh that harm or loss, or all of the following apply: • a) the nature of the heritage asset prevents all reasonable uses of the site; and • b) no viable use of the heritage asset itself can be found in the medium term through appropriate marketing that will enable its conservation; and • c) conservation by grant-funding or some form of not for profit, charitable or public ownership is demonstrably not possible; and • d) the harm or loss is outweighed by the benefit of bringing the site back into use. Para 196. Where a development proposal will lead to less than substantial harm to the significance of a designated heritage asset, this harm should be weighed against the public benefits of the proposal including, where appropriate, securing its optimum viable use. Para 197. The effect of an application on the significance of a non-designated heritage asset should be taken into account in determining the application. In weighing applications that directly or indirectly affect non-designated heritage assets, a balanced judgement will be required having regard to the scale of any harm or loss and the significance of the heritage asset. Para 198. Local planning authorities should not permit the loss of the whole or part of a heritage asset without taking all reasonable steps to ensure the new development will proceed after the loss has occurred. Para 199. Local planning authorities should require developers to record and advance understanding of the significance of any heritage assets to be lost (wholly or in part) in a manner proportionate to their importance and the impact, and to make this evidence (and any archive generated) publicly accessible. However, the ability to record evidence of our past should not be a factor in deciding whether such loss should be permitted. Para 200. Local planning authorities should look for opportunities for new development within Conservation Areas and World Heritage Sites, and within the setting of heritage assets, to enhance or better reveal their significance. Proposals that preserve those elements of the setting that make a positive contribution to the asset (or which better reveal its significance) should be treated favourably.
Archaeological Desk Based Assessment © MOLA 2020 28 Grain LNG Phase 3B3B 09/12/2020 Para 201. Not all elements of a Conservation Area or World Heritage Site will necessarily contribute to its significance. Loss of a building (or other element) which makes a positive contribution to the significance of the Conservation Area or World Heritage Site should be treated either as substantial harm under paragraph 195 or less than substantial harm under paragraph 196, as appropriate, taking into account the relative significance of the element affected and its contribution to the significance of the Conservation Area or World Heritage Site as a whole. Para 202. Local planning authorities should assess whether the benefits of a proposal for enabling development, which would otherwise conflict with planning policies but which would secure the future conservation of a heritage asset, outweigh the disbenefits of departing from those policies.
9.2 Local planning policy
9.2.1 Following the Planning and Compulsory Purchase Act 2004, Planning Authorities have replaced their Unitary Development Plans (UDPs), Local Plans and Supplementary Planning Guidance with a new system of Local Development Frameworks (LDFs). UDP policies have been either ‘saved’ or ‘deleted’. In most cases archaeology policies are likely to be ‘saved’ because there have been no significant changes in legislation or advice at a national level. 9.2.2 The following planning policies are derived from the Medway Council Local Plan, adopted in 2003:
Policy S3: River Medway Proposals which are consistent with nature conservation, landscape and hydrological policies and which have no adverse impact upon coastal archaeology will be permitted that develop the River Medway for: (i) public access along the riverbank through the construction of riverside walks and cycle-ways; (ii) use as a transportation corridor, both for freight and passengers; (iii) appropriate commercial, tourism and leisure development along the river’s edge of a high quality design; (iv) recreational and tourism purposes. The inter-tidal habitats of the Medway are an important natural resource. Where any proposed development would affect the inter-tidal habitats, an assessment of its impact will be required. Where development is proposed that will result in any loss of inter-tidal habitats, proposals must include compensatory inter-tidal habitats sufficient to mitigate any loss.
Policy BNE21: Archaeological Sites Development affecting potentially important archaeological sites will not be permitted, unless: (i) the developer, after consultation with the archaeological officer, has arranged for an archaeological field evaluation to be carried out by an approved archaeological body before any decision on the planning application is made; and (ii) it would not lead to the damage or destruction of important archaeological remains. There will be a preference for the preservation of important archaeological remains in situ. (iii) where development would be damaging to archaeological remains, sufficient time and resources are made available for an appropriate archaeological investigation undertaken by an approved archaeological body. Such investigations should be in advance of development and in accordance with a specification and programme of work approved by the council. Resources should also be made available for the publication of the results of the investigation.
Supporting Text
Archaeology Paragraph 3.4.55. The lower reaches of the Thames and Medway estuaries have played a strategic role in the development of Kent from prehistoric times onwards and sites of all periods from the Palaeolithic to the modern are represented. The local plan needs to address
Archaeological Desk Based Assessment © MOLA 2020 29 Grain LNG Phase 3B3B 09/12/2020 this legacy which is represented by Scheduled Ancient Monuments and other important archaeological sites.
Nationally Important Archaeological Sites Paragraph 3.4.56. The planning system must protect nationally important archaeological remains, some of which enjoy special protection as Scheduled Ancient Monuments. National policy, as set out in PPG16, makes a presumption in favour of the physical preservation, in situ, of nationally important remains and their settings. In view of their intrinsic worth as historic sites and buildings, it is essential that the monuments themselves are protected and that unsympathetic or damaging development is not allowed in their immediate vicinity. In addition to planning controls, separate Scheduled Ancient Monument consent from the First Secretary of State is required before specified works are carried out which would affect an Ancient Monument. The sites which were scheduled in May 1999 are set out in Appendix 1 and their general locations are identified on the proposals map. The policy will also apply to monuments which are subsequently scheduled.
Other Important Archaeological Sites Paragraph 3.4.57. On the basis of information from the Kent Archaeological Sites and Monuments Record, Areas of Archaeological Potential have been identified. These cover broad areas of land which might contain archaeological remains, although there is no indication of their relative importance. It is not the intention of Medway Council to prevent development in such areas, but to provide an opportunity for their importance to be assessed at the earliest possible stage and for development to be designed to minimise destruction as a first preference. Where this approach is not warranted, arrangements for excavation and recording of details should be made, and any important artefacts removed for curating, usually in a museum. Paragraph 3.4.58. Development within Areas of Archaeological Potential which involves disturbance of below ground deposits could damage or destroy archaeological remains. For this reason, planning applications for development within these sites and others where archaeological remains are believed to be present will be the subject of consultation with the archaeological officer in order to assess the potential archaeological importance of the site. The council will seek to protect important archaeological remains in situ, and to avoid or minimise damage to these deposits. However, where damage is unavoidable, appropriate archaeological investigation will be required in advance of development. In some cases this may take the form of initial evaluation work followed by more formal excavation. Paragraph 3.4.59. The importance of coastal archaeology should also be borne in mind. There is a need for further survey work to assess coastal archaeology. 9.2.3 A new Local Plan Future Medway (2019 to 2037) is underway and will replace the 2003 Medway Local Plan. The draft Local Plan publication is due in 2021.
Archaeological Desk Based Assessment © MOLA 2020 30 Grain LNG Phase 3B3B 09/12/2020 10 Determining significance
10.1.1 ‘Significance’ lies in the value of a heritage asset to this and future generations because of its heritage interest, which may be archaeological, architectural, artistic or historic. Archaeological interest includes an interest in carrying out an expert investigation at some point in the future into the evidence a heritage asset may hold of past human activity, and may apply to standing buildings or structures as well as buried remains. Known and potential heritage assets within the site and its vicinity have been identified from national and local designations, HER data and expert opinion. The determination of the significance of these assets is based on statutory designation and/or professional judgement against four values (EH 2008): • Evidential value: the potential of the physical remains to yield evidence of past human activity. This might take into account date; rarity; state of preservation; diversity/complexity; contribution to published priorities; supporting documentation; collective value and comparative potential. • Aesthetic value: this derives from the ways in which people draw sensory and intellectual stimulation from the heritage asset, taking into account what other people have said or written; • Historical value: the ways in which past people, events and aspects of life can be connected through heritage asset to the present, such a connection often being illustrative or associative; • Communal value: this derives from the meanings of a heritage asset for the people who know about it, or for whom it figures in their collective experience or memory; communal values are closely bound up with historical, particularly associative, and aesthetic values, along with and educational, social or economic values. 10.1.2 Consultation on draft revisions to the original Conservation Principles document which set out the four values was open from November 2017 until February 2018. The revisions aim to make them more closely aligned with the terms used in the NPPF (which are also used in designation and planning legislation): i.e. as archaeological, architectural, artistic and historic interest. This is in the interests of consistency, and to support the use of the Conservation Principles in more technical decision-making (HE 2017). 10.1.3 Table 2 gives examples of the significance of designated and non-designated heritage assets.
Table 2: Significance of heritage assets Heritage asset description Significance World heritage sites Very high Scheduled monuments (International/ Grade I and II* listed buildings national) Historic England Grade I and II* registered parks and gardens Protected Wrecks Heritage assets of national importance Historic England Grade II registered parks and gardens High Conservation areas (national/ Designated historic battlefields regional/ Grade II listed buildings county) Burial grounds Protected heritage landscapes (e.g. ancient woodland or historic hedgerows) Heritage assets of regional or county importance Heritage assets with a district value or interest for education or cultural appreciation Medium Locally listed buildings (District) Heritage assets with a local (i.e. parish) value or interest for education or cultural Low appreciation (Local) Historic environment resource with no significant value or interest Negligible Heritage assets that have a clear potential, but for which current knowledge is Uncertain insufficient to allow significance to be determined
10.1.4 Unless the nature and exact extent of buried archaeological remains within any given area has been determined through prior investigation, significance is often uncertain.
Archaeological Desk Based Assessment © MOLA 2020 31 Grain LNG Phase 3B3B 09/12/2020 11 Non-archaeological constraints
11.1.1 It is anticipated that live services will be present on the site, the locations of which have not been identified by this archaeological report. 11.1.2 Note: the purpose of this section is to highlight to decision makers any relevant non- archaeological constraints identified during the study, that might affect future archaeological field investigation on the site (should this be recommended). The information has been assembled using only those sources as identified in section 2 and section 13.4, in order to assist forward planning for the project designs, working schemes of investigation and risk assessments that would be needed prior to any such field work. MOLA has used its best endeavours to ensure that the sources used are appropriate for this task but has not independently verified any details. Under the Health & Safety at Work Act 1974 and subsequent regulations, all organisations are required to protect their employees as far as is reasonably practicable by addressing health and safety risks. The contents of this section are intended only to support organisations operating on this site in fulfilling this obligation and do not comprise a comprehensive risk assessment.
Archaeological Desk Based Assessment © MOLA 2020 32 Grain LNG Phase 3B3B 09/12/2020 12 Glossary
Alluvium Sediment laid down by a river. Can range from sands and gravels deposited by fast flowing water and clays that settle out of suspension during overbank flooding. Other deposits found on a valley floor are usually included in the term alluvium (e.g. peat). Archaeological Areas of archaeological priority, significance, potential or other title, often designated by Priority Area/Zone the local authority. Brickearth A fine-grained silt believed to have accumulated by a mixture of processes (e.g. wind, slope and freeze-thaw) mostly since the Last Glacial Maximum around 17,000BP. B.P. Before Present, conventionally taken to be 1950 Bronze Age 2,000–600 BC Building recording Recording of historic buildings (by a competent archaeological organisation) is undertaken ‘to document buildings, or parts of buildings, which may be lost as a result of demolition, alteration or neglect’, amongst other reasons. Four levels of recording are defined by Royal Commission on the Historical Monuments of England (RCHME) and Historic England. Level 1 (basic visual record); Level 2 (descriptive record), Level 3 (analytical record), and Level 4 (comprehensive analytical record) Built heritage Upstanding structure of historic interest. Colluvium A natural deposit accumulated through the action of rainwash or gravity at the base of a slope. Conservation area An area of special architectural or historic interest the character or appearance of which it is desirable to preserve or enhance. Designation by the local authority often includes controls over the demolition of buildings; strengthened controls over minor development; and special provision for the protection of trees. Cropmarks Marks visible from the air in growing crops, caused by moisture variation due to subsurface features of possible archaeological origin (i.e. ditches or buried walls). Cut-and-cover Method of construction in which a trench is excavated down from existing ground level [trench] and which is subsequently covered over and/or backfilled. Cut feature Archaeological feature such as a pit, ditch or well, which has been cut into the then- existing ground surface. Desk-based A written document whose purpose is to determine, as far as is reasonably possible from assessment existing records, the nature of the historic environment resource/heritage assets within a specified area. Devensian The most recent cold stage (glacial) of the Pleistocene. Spanning the period from c 70,000 years ago until the start of the Holocene (10,000 years ago). Climate fluctuated within the Devensian, as it did in other glacials and interglacials. It is associated with the demise of the Neanderthals and the expansion of modern humans. Early medieval AD 410–1066. Also referred to as the Saxon period. Evaluation A limited programme of non–intrusive and/or intrusive fieldwork which determines the (archaeological) presence or absence of archaeological features, structures, deposits, artefacts or ecofacts within a specified area. Excavation A programme of controlled, intrusive fieldwork with defined research objectives which (archaeological) examines, records and interprets archaeological remains, retrieves artefacts, ecofacts and other remains within a specified area. The records made and objects gathered are studied and the results published in detail appropriate to the project design. Findspot Chance find/antiquarian discovery of artefact. The artefact has no known context, is either residual or indicates an area of archaeological activity. Geotechnical Ground investigation, typically in the form of boreholes and/or trial/test pits, carried out for engineering purposes to determine the nature of the subsurface deposits. Head Weathered/soliflucted periglacial deposit (i.e. moved downslope through natural processes). Heritage asset A building, monument, site, place, area or landscape positively identified as having a degree of significance meriting consideration in planning decisions. Heritage assets are the valued components of the historic environment. They include designated heritage assets and assets identified by the local planning authority (including local listing). Historic Environment Archaeological and built heritage database held and maintained by the County authority. Record (HER) Previously known as the Sites and Monuments Record Holocene The most recent epoch (part) of the Quaternary, covering the past 10,000 years during which time a warm interglacial climate has existed. Also referred to as the ‘Postglacial’ and (in Britain) as the ‘Flandrian’. Iron Age 600 BC–AD 43
Archaeological Desk Based Assessment © MOLA 2020 33 Grain LNG Phase 3B3B 09/12/2020 Later medieval AD 1066 – 1500 Last Glacial Characterised by the expansion of the last ice sheet to affect the British Isles (around Maximum 18,000 years ago), which at its maximum extent covered over two-thirds of the present land area of the country. Locally listed A structure of local architectural and/or historical interest. These are structures that are not building included in the Secretary of State’s Listing but are considered by the local authority to have architectural and/or historical merit Listed building A structure of architectural and/or historical interest. These are included on the Secretary of State's list, which affords statutory protection. These are subdivided into Grades I, II* and II (in descending importance). Made Ground Artificial deposit. An archaeologist would differentiate between modern made ground, containing identifiably modern inclusion such as concrete (but not brick or tile), and undated made ground, which may potentially contain deposits of archaeological interest. Mesolithic 12,000 – 4,000 BC National Record for National database of archaeological sites, finds and events as maintained by Historic the Historic England in Swindon. Generally not as comprehensive as the county HER. Environment (NRHE) Neolithic 4,000 – 2,000 BC Ordnance Datum A vertical datum used by Ordnance Survey as the basis for deriving altitudes on maps. (OD) Palaeo- Related to past environments, i.e. during the prehistoric and later periods. Such remains environmental can be of archaeological interest, and often consist of organic remains such as pollen and plant macro fossils which can be used to reconstruct the past environment. Palaeolithic 700,000–12,000 BC Palaeochannel A former/ancient watercourse Peat A build-up of organic material in waterlogged areas, producing marshes, fens, mires, blanket and raised bogs. Accumulation is due to inhibited decay in anaerobic conditions. Pleistocene Geological period pre-dating the Holocene. Post-medieval AD 1500–present Preservation by Archaeological mitigation strategy where archaeological remains are fully excavated and record recorded archaeologically and the results published. For remains of lesser significance, preservation by record might comprise an archaeological watching brief. Preservation in situ Archaeological mitigation strategy where nationally important (whether Scheduled or not) archaeological remains are preserved in situ for future generations, typically through modifications to design proposals to avoid damage or destruction of such remains. Registered Historic A site may lie within or contain a registered historic park or garden. The register of these Parks and Gardens in England is compiled and maintained by Historic England. Residual When used to describe archaeological artefacts, this means not in situ, i.e. Found outside the context in which it was originally deposited. Roman AD 43–410 Scheduled An ancient monument or archaeological deposits designated by the Secretary of State as Monument a ‘Scheduled Ancient Monument’ and protected under the Ancient Monuments Act. Site The area of proposed development Site codes Unique identifying codes allocated to archaeological fieldwork sites, e.g. evaluation, excavation, or watching brief sites. Study area Defined area surrounding the proposed development in which archaeological data is collected and analysed in order to set the site into its archaeological and historical context. Solifluction, Creeping of soil down a slope during periods of freeze and thaw in periglacial Soliflucted environments. Such material can seal and protect earlier landsurfaces and archaeological deposits which might otherwise not survive later erosion. Stratigraphy A term used to define a sequence of visually distinct horizontal layers (strata), one above another, which form the material remains of past cultures. Truncate Partially or wholly remove. In archaeological terms remains may have been truncated by previous construction activity. Watching brief A formal programme of observation and investigation conducted during any operation (archaeological) carried out for non-archaeological reasons.
Archaeological Desk Based Assessment © MOLA 2020 34 Grain LNG Phase 3B3B 09/12/2020 13 Bibliography
13.1 Published and documentary sources
Atkins, 08–2019 Isle of Grain Business Park: Interpretative Site Investigation Report. Unpublished grey literature Bates M.R 1999 A geoarchaeological assessment of a borehole from the Kingsnorth Power Station site, Hoo St. Werburgh, Rochester-upon-Medway. Unpublished grey literature Bridgland D.R 2006 The Middle and Upper Pleistocene sequence in the Lower Thames: a record of Milankovitch climatic fluctuation and early human occupation of southern Britain. Proceedings of the Geologists’ Association, 117, 281–306. Burnett C.B 1906 History of the Isle of Grain CIfA [Chartered Institute for Archaeologists] 2014a, Standards and guidance for commissioning work or providing consultancy advice on archaeology and the historic environment, Published December 2014, Reading. CIfA [Chartered Institute for Archaeologists] 2017, Standards and guidance for historic environment desk-based assessment, Published December 2014, updated January 2017, Reading DCLG [Department of Communities and Local Government], March 2012 National Planning Policy Framework DCLG [Department of Communities and Local Government], March 2014 Conserving and Enhancing the Historic Environment: Planning Practice Guide Domesday Book, A Complete Translation, eds Williams, A. and Martin, G.H. 1992, 2002. London: Penguin Books EH [English Heritage], 2008 Conservation principles, policies and guidance. Swindon EH [English Heritage], 2014 Isle of Grain, Hoo Peninsula, Kent – Historic Area Assessment, London Evans J.H 1949 ‘Roman remains from Upchurch Marshes’ in: Archaeologia Cantiana, 62, 146–7 Evans J.H 1950 ‘Researches and Discoveries in Kent, 1950’ in: Archaeologia Cantiana, 63, 145–6 Evans J.H 1953 ‘Archaeological horizons in North Kent Marshes’ in: Archaeologia Cantiana, 66, 103–4 Gray A, 1974, Isle of Grain Railways Gibbard PL, 1994 The Pleistocene history of the lower Thames valley, Cambridge Hasted, E. 1798, ‘Parishes: Gillingham’, in The History and Topographical Survey of the County of Kent: Volume 4. Canterbury: W Bristow. British History Online http://www.british- history.ac.uk/survey-kent/vol4/pp226-249 [accessed 6 September 2019 HM Government, March 2011 UK Marine Policy Statement. London: The Stationery Office. HE [Historic England] 2015a, The Setting of Heritage Assets – Historic Environment Good Practice Advice in Planning: 3. Historic England in collaboration with the Historic Environment Forum, second edition, Historic England July 2015. HE [Historic England] 2015b Managing Significance in Decision-Taking in the Historic Environment – Historic Environment Good Practice Advice in Planning: 2. Historic England in collaboration with the Historic Environment Forum, second edition, Historic England July 2015. HE [Historic England] 2017 Conservation Principles for the Sustainable Management of the Historic Environment, Consultation Draft, 10th November 2017 https://content.historicengland.org.uk/content/docs/guidance/conservation-principles-consultation- draft.pdf Humphery-Smith C, 1984 The Phillimore Atlas and Index of Parish Registers. MacDougal P, 1980 The Isle of Grain Defences Medway Council, May 2003 Medway Local Plan. Adopted May 2003 MHCLG [Ministry of Housing, Communities and Local Government], 2019 National Planning Policy Framework, revised February 2019 Monaghan J, 1987 Upchurch and Thameside Roman Pottery. A ceramic typology of northern Kent, 1st to 3rd centuries AD. BAR Series 173. Oxford: BAR MoLAS [Museum of London Archaeology Service], 2000 The archaeology of Greater London: an assessment of archaeological evidence for human presence in the area covered by modern Greater London. London MoLAS, 2005 Additional LNG Storage Tanks – Grain LNG, Isle of Grain: An archaeological watching brief. MoLAS: Unpublished grey literature
Archaeological Desk Based Assessment © MOLA 2020 35 Grain LNG Phase 3B3B 09/12/2020 MoLAS, 2006 Grain LNG Storage Site, Isle of Grain, Kent: An archaeological desk-based assessment. MoLAS: Unpublished grey literature MOLA, 2014 Grain Business Park, Isle of Grain, Kent: Historic Environment Assessment. MOLA: Unpublished grey literature MOLA, 2019 Sub-Phase 1A Grain Business Park, Isle of Grain, Kent: Historic Environment Assessment. MOLA: Unpublished grey literature National Grid, 2006, Grain LNG Importation Facility Environmental Impact Assessment Volume 1 Environmental Statement: Grain LNG Phase 3 Expansion. Nation Grid: Unpublished grey literature Newman J, 1976 (2nd ed.) The Buildings of England: West Kent and the Weald Rankov N, 1982. ‘Roman Britain in 1981’ in: Britannia Vol. XIII, 1982, London: Society for the Promotion of Roman Studies RCHME 1998 Coastal Artillery Fortifications on the Isle of Grain, Kent Coastal Artillery Fortifications Rippons S, 2000 ‘The Transformation of the Coastal Wetlands’ in: Exploitation and management of marshland landscapes in North West Europe. Oxford Saunders A and Smith V, 2001 Kent’s Defensive Heritage Soil mechanics, 2010 Grain LNG Phase 4 Ground Investigation, Isle of Grain, Kent: Factual report on Ground Investigation Wessex Archaeology, 2005 North Kent Coast Rapid Coastal Zone Assessment Survey, Phase II: Field Assessment, Year One Report. KCC: Unpublished grey literature Williams J and Brown N, (eds.) 1999 An Archaeological Research Framework for the Greater Thames Estuary. Essex County Council: Kent County Council: English Heritage Whittaker K, 1991 A Report on the Archaeological and Historical Significance of the North Kent Marshes
13.2 Other Sources
British Geological Survey online historic geology borehole data and digital drift and solid geology data Kent County Historic Environment Record Historic England designation data Groundsure historic Ordnance Survey mapping Museum of London Archaeological Archive
13.3 Cartographic sources
Grain Parish Tithe Map of 1839
Ordnance Survey maps Ordnance Survey 1st edition 5”: mile map (1863) Ordnance Survey 1:2,500 scale maps (1967, 1993)
Engineering/Architects drawings Redline Boundary Plan (National Grid 2020) Northern Zone Plot Plan LNG Storage and Regasification Area (National Grid, PL3/PLA/108, Rev A1, 31/08/2007) Section Through LNG Tank (National Grid, Figure 3.3, June 2006)
13.4 Available site survey information checklist
Information from client Available Format Obtained Plan of existing site services (overhead/buried) not known - N Levelled site survey as existing (ground and not known - N buildings) Contamination survey data ground and buildings (inc. Y pdf Y asbestos) Geotechnical report Y pdf Y Envirocheck report T pdf Y
Archaeological Desk Based Assessment © MOLA 2020 36 Grain LNG Phase 3B3B 09/12/2020 Information obtained from non-client source Carried out Internal inspection of buildings Site inspection N N
Archaeological Desk Based Assessment © MOLA 2020 37 Grain LNG Phase 3B3B 09/12/2020 Archaeological desk-based assessment © MOLA 2020
Brentwood Billericay Rayleigh
Havering Basildon Southend-on-Sea London Canvey Island the site Grays Bexley Sheerness Gravesend Dartford
Bromley Rochester Gillingham
Sittingbourne Chatham Canterbu
Sevenoaks Maidstone
010km Tonbridge 0 500m
586500 586600 586700 586800 586900 587000 587100 587200 587300 587400 587500 176500 176400 176300 176200 the site 176100
Phase 3B area 176000 175900 175800
construction laydown area 175700 175600 175500 175400 175300
Contains Ordnance© Crown CopyrightSurvey data 2020. All rights reserved. 0250m © Crown copyrightLicence and database Number right 100047514 2014 scale 1:7,500 @ A4
Fig 1 Site location
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past archaeological investigation (KHER area) study area 174000 )" past archaeological investigation (KHER point) site outline Phase 3B area archaeological feature (KHER line) construction laydown area (! archaeological feature/findspot (KHER point) Archaeological Priority and Conservation Areas not shown
Contains Ordnance Survey data 0550m © Crown copyright and database right 2020 scale 1:15,000 @ A4
Fig 2 Historic environment features map
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head (undifferentiated)
river terrace deposits, 2 Licence No. 2002/140 British Geological Survey © NERC. All rights reserved
Contains Ordnance Survey data 0250m © Crown copyright and database right 2020 scale 1:7,000 @ A4
Fig 3 Geological features, geotechnical survey data (Soil Mechanics 2010) and historic borehole data (BGS 2020) map
KENT2045DBA20#03 Archaeological desk-based assessment © MOLA 2020
the site
Fig 4 Grain Parish Tithe Map of 1839
Phase 3B area
construction laydown area
Fig 5 Ordnance Survey 1st edition 25”:mile map of 1863 (not to scale)
KENT2045DBA20#04&05 Archaeological desk-based assessment © MOLA 2020
Phase 3B area
construction laydown area
Fig 6 Ordnance Survey 1:2,500 scale map of 1967 (not to scale)
Phase 3B area
construction laydown area
Fig 7 Ordnance Survey 1:2,500 scale map of 1993 (not to scale)
KENT2045DBA20#06&07 T355 Tank
the site
Fencing Export Facility Laydown Area
Archaeological desk-based assessment
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Fig 8 Site Layout, showing existing site and surrounding area layout and proposed new T355 Tank location (National Grid 2020) Archaeological desk-based assessment MOLA 2020 the site Tank Layout Plan showing existing and proposed Phase 3B construction (National Grid, PL3/PLA/108, RevTank A1, 31/08/2007) Fig 9
KENT2045DBA20#09 Archaeological desk-based assessment MOLA 2020 LNG Storage (National Grid, Figure 3.3, June 2006) Section and Plan View Tank Fig 10
KENT2045DBA20#10 National Grid Grain LNG Limited Grain LNG Phase 3B
APPENDIX 1.4: WATER RESOURCES TECHNICAL NOTE
ES Volume 2: Technical Appendices
Technical Note
Project: Isle of Grain - Grain LNG Expansion Northern Zone Project (planning application ref. MC2007/1683, amendment of MC2006/1428)
Subject: Water Resource Commentary on the Environmental Statement 2006
Author: Atkins
Date: 11/12/2020 Project No.: 5186422
Distribution: Andy Collins Representing: National Grid GLNG James Bumphrey Greengage
Document history Revision Purpose description Originated Checked Reviewed Authorised Date Rev 1.0 Draft CB PJB KB LH 30/10/20 Rev 2.0 Final CB PJB KB LH 10/11/20 Rev 3.0 Final CB PJB KB LH 11/11/20 Rev 4.0 Final CB PJB KB LH 24/11/20 Rev 5.0 Final CB PJB KB LH 27/11/20 Rev 6.0 Final CB PJB KB LB 11/12/20
Client signoff Client National Grid Project Isle of Grain - Grain LNG Expansion Northern Zone Project (planning application ref. MC2007/1683, amendment of MC2006/1428) Project No. 5186422
Client signature / date
IoG_EIAreview_Water Resources | 6.0 | 11/12/2020 Atkins | ES Water Technical Note_v6_FINAL_LB Page 1 of 6
1. Introduction Atkins Limited (Atkins) has been instructed by National Grid Grain LNG Limited (GLNG) to review and appraise existing information relating to water for two liquefied natural gas (LNG) storage tanks at the Grain LNG Importation Facility located on the Isle of Grain, Kent (“the Site”). This review has been prepared to support planning condition discharge associated with the existing planning permission as part of an updated Environmental Statement (ES) being coordinated by Greengage Environmental Limited (Greengage). A 2006 ES [1] and 2007 ES update [2] were originally prepared in support of the development, which included the construction of two LNG storage tanks, associated processing equipment, a jetty and other related infrastructure (Planning Ref: MC2006/1428, amended to MC2007/1683). One of LNG storage tanks (known as Phase 3A) has now been constructed, with GLNG currently progressing works in preparation for the construction of the second tank (known as Phase 3B). Given the time that has passed since the original ESs were produced, Atkins have been instructed to review the ES and subsequent site assessments to determine if baseline conditions and proposed mitigation measures are still applicable and confirm, or otherwise, that no significant water impacts are anticipated in relation to construction of the Phase 3B storage tank. Given that the Phase 3A tank and associated infrastructure has already been constructed and has been operational since 2010, the Phase 3A area has been considered as part of the updated baseline. 2. Commentary Regarding Planning Policy/ Legislative Context
National Planning Policy The original Flood Risk Assessment was prepared in accordance with PPS25 Development & Flood Risk. This was superseded in March 2012 by the NPPF with the content of PPS25 being transferred into the NPPF Technical Guidance. Subsequently, in March 2014, the Technical Guidance was replaced by Planning Practice Guidance. The Flood & Water Management Act 2010 was introduced after the 2006 and 2007 ESs had been prepared. The various parts of this are progressively becoming enacted. This does not affect any of the conclusions of the assessments within the 2006 and 2007 ESs; however, there have been a number of changes in Environment Agency policy and requirements as a result. These are primarily associated with drainage systems, the use of sustainable drainage techniques (SuDS) and adoption, ownership and maintenance arrangements.
Regional & Local Planning Policy Medway Council have become the Lead Local Flood Authority for the area including the development site. The Medway Local Plan 2003 remains the current planning policy document for the development site. The relevant policies are listed below: S3 River Medway S13 Isle of Grain ED1 Existing employment areas ED5 Proposed employment areas BNE35 International and national nature conservation sites BNE36 Strategic and local nature conservation sites CF13 Tidal flood risk areas The Plan includes the following specific information relevant to this Assessment: It is expected that sea defences will need to be raised over time to provide ongoing protection from tidal surges. Where there is a risk of tidal flooding, the development should be designed such that the maximum depth of flooding will be no more than 1.2m. Sustainable drainage systems, designed in accordance with guidance published by several local authorities in the south-east of England, are encouraged.
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Emerging Medway Local Plan Pre-Consultation Draft (2018-2035) The following sections are drawn from the Development Options consultation document and could potentially become relevant in addressing in order to comply with future Medway Council policy.
Policy Approach: Economic Development The proposed policy has a focus on the use of the future development of the Isle of Grain site: Secure sustainable employment uses for the strategic sites at Grain and Kingsnorth, achieving value from the specific location offer and the access to water and rail for freight movements.
Policy Approach: Strategic Access Management and Monitoring The Medway Estuary had another environmental designation applied and as such there will be continued scrutiny of the operators who use or discharge into the Medway and their compliance with standards: The Medway Estuary from Rochester to the Isle of Grain was designated as a Marine Conservation Zone (MCZ) in the first round of designations in 2013. This protects a nationally scarce species of tentacled lagoon-worm and a number of habitats and their associated wildlife. The health of the MCZ will largely be achieved through the licensing regimes that manage activities taking place on the river or seabed, but the council as local planning authority must consider the potential impact of developments proposed along the coast. Medway Council adopted an interim Policy Statement in November 2015 to provide a basis for its implementation of the Strategic Access Management and Mitigation programme. It is the council’s intention that the new Local Plan will include a policy on this matter to seek to avoid damage to the protected characteristics of the Thames, Medway and Swale SPA and Ramsar sites.
Policy Approach: Flood Risk The approach to Flood Risk Management remains and will be further covered in future policies: Much of the land along the shoreline of the Isle of Grain, the south side of the River Medway and lower lying land towards Cuxton and Halling is within Flood Zone 3. Large areas of Strood and Medway City Estate lie within either Flood Zones 2 or 3. A Local Plan policy to manage flood risk from all sources will be developed in partnership with the Environment Agency and other flood risk management bodies. In line with the NPPF and PPG, the policy will apply a sequential, risk-based approach and prioritise the use of sustainable drainage systems. The policy will draw on the Environment Agency’s Thames Estuary 2100 Plan, South East Coastal Group’s Shoreline Management Plans and the forthcoming Medway and Swale Estuary Strategy. It will also be supported by the Strategic Flood Risk Assessment, the Local Flood Risk Management Strategy and associated policies in progress.
Habitat Regulations Assessment: Screening Report (April 2017) This report details the HRA Screening undertaken for Medway Council’s Local Plan Development Options consultation report. This should be read in conjunction with the interim Sustainability Appraisal published in March 2017. The following text is an extract from the HRA report 2017, at Section 3.14. This report recognises the existing planning permission for Phase 3b and the current employment land boundaries, but stresses that any alteration to those boundaries would be subject to a “robust assessment”. It should be noted that the boundaries for the development remain unchanged. The Development Options policy approach to Economic Development notes the role of the strategic employment sites at Grain and Kingsnorth. Both sit adjacent to the Medway Estuary and Marshes SPA and Ramsar site. These sites have extant employment allocations and there are existing planning consents that have included Appropriate Assessments of the potential for adverse impacts on the integrity of the designated European sites. There is a risk that any expansion of the employment areas could result in the loss of designated or supporting habitats. Any changes to the employment area boundaries that may be considered through the emerging Local Plan would need to be subject to robust assessment to avoid the loss or fragmentation of designated or supporting habitats.
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3. Commentary Regarding the Environment Statement 2006 & 2007
Baseline Conditions The principles of the surface water discharge from the site have not changed since the 2006 and 2007 ESs were prepared. There remains the two original gravity ditch systems and the pumped surface water drainage system. However, there have been maintenance works undertaken to the pumped surface water drainage system. Sump 8 (located within the assessment area) was replaced with a gravity system to a new pump Sump 9A (outside the assessment area, approximately 40m from the red line boundary). This lifted surface water into the existing Sump 9 (located immediately adjacent to Sump 9A). From there, nearly 1,000 m of the existing pumped main was replaced, in order to provide increased longevity and reduce pipe bursts on the older pumped system. This will provide the site environment with a greater protection from flooding (due to pipe bursts) and provides associated water quality protection. During the civils works, monitoring of materials and groundwater was undertaken regularly. The results showed that groundwater occurring within the excavation was of sufficient quality to pass through the interceptors and be discharged into the Medway.
Potential Impacts, Mitigation, Residual Impact & Cumulative Impacts In headline terms, the conclusions reached in the 2006 and 2007 ESs regarding: surface hydrology, water quality, sediment release, materials storage for both the Construction activities and the Operational activities related to surface water and foul water are considered to remain unaltered. These potential risks have been identified and the mitigation and residual risks are still relevant and are correctly identified. Examples of these mitigations are captured in the implementation of the Construction Environmental Management Plan (CEMP) which will be prepared in accordance with best practice, although this is not a specific planning requirement. This will mitigate environmental risk through measures such as: Not storing such materials within 30m of “main” watercourses, 10m of all other watercourses and 50m of any borehole; No refuelling of mobile plant within these areas; Mobile plant being integrally bunded or placed on drip trays; Mobile bowsers to be bunded; Plant to be regularly checked for leaks and is well maintained; Crews will be issued with spill control measures and booms; Crews will be inducted with environmental management procedures and how to use appropriate control equipment; and a permit to pump system will be put in place to ensure that pumps are set up, operated and controlled by suitably trained personnel. 4. Commentary Regarding Flood Risk On an adjacent part of the GLNG site (near to Phase 3B), a Reserved Matters submission was made in 2014/15 to Medway Council for a proposed Employment Development, pursuant to an approved outline planning submission from 2010. The flood risk was identified for that development and the following issues are relevant to the Phase 3B proposals. The Phase 3B and Laydown area is located within defended Flood Zone 3. The principle sources of flood risk affecting the site are tidal, surface water and groundwater. All other sources are considered to present either a low or negligible risk.
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The development site benefits from sea defences both around the coast and further inland. The coastal defences have a crest level of approximately 6.0m AOD. Extreme (1 in 200-year) sea levels for 2010 and 2070 are both shown to be below this level hence the risk of direct overtopping of the defences is considered minimal. Analysis has shown that wave overtopping will occur; however, the resultant flood extents only encroach into the area south of Grain Road, east of the internal sea wall which is not proposed for development. On this basis, it is concluded that the risk of flooding of the development from wave overtopping is minimal. Analysis of breaches in the sea defences during an extreme high tide also demonstrated that flooding did not affect the Phase 3A nor Phase 3B site areas. The risk of surface water flooding is considered to be low and capable of being mitigated using appropriate flood risk management measures. Over the majority of the development site the depth of flooding is minimal, while a greater depth occurs around drainage ditches and low lying areas, such as former storage tank bases. Following periods of prolonged rainfall, as a result of high groundwater levels beneath much of the development site, groundwater has been known to emerge onto the surface. In general, the depths of flooding are shallow; however, due to the nature of this type of flooding, the flooding remains for a prolonged period of time. Due to the shallow depth of flooding, the risk to the development is considered to be low; flood risk management measures will assist in reducing the duration of the flooding. The existing surface water drainage system comprises a combination of gravity and pumped systems. The site drains to outfalls into the River Medway. It is proposed that these will continue to be used post-development. There are currently no discharge rate restrictions into the river; therefore, the development will also have an unrestricted discharge rate. The surface water drainage system serving the development will incorporate SuDS, primarily for water treatment purposes but also to provide storage in order to manage particular outfall conditions. The River Medway has a number of conservation designations; therefore, the quality of the water discharged from the development is important. As regards the design of new surface water features to address flood risk, under the original planning approval: PC13 The development hereby permitted shall not be commenced until details of the means of control and disposal of foul and surface water during the construction and operational phases of the development have been submitted to and approved in writing by the Local Planning Authority. The submitted scheme of details shall include the provision of petrol/oil inceptors as appropriate. The approved scheme of details shall be implemented to accommodate foul and surface water during construction and retained thereafter. and the subsequently granted non material amendment MC/20/2664, Planning Condition 11: No development shall take place within a phase until a scheme showing details of the disposal of surface water based on sustainable drainage principles, including detail of the design, implementation. maintenance and management of the surface water drainage scheme for both the construction and operational phases of the development have been submitted to and approved in writing by the Local Planning Authority. Those details shall include provision of petrol/oil inceptors as appropriate and the following: i. a timetable for its implementation, and ii. a management and maintenance plan for the lifetime of the development which shall include the arrangements for adoption by any public body or statutory undertaker, or any other arrangements to secure the operation of the sustainable drainage scheme throughout its lifetime. The development shall be implemented in accordance with the approved details and shall thereafter be retained. the EA/LLFA have the option to revisit any design work and its satisfactory implementation through the wording of these planning conditions. This will mean that the LPA (Medway Council, who are also the Lead Local Flood Authority, LLFA) could and probably will consult with the EA for their approval to discharge MC/2006/1428 PC13 and MC/20/2664 PC11. Generally, in this situation, the EA/LLFA will ensure that the most recent policies, standards and guidance are being used. The most pertinent change in design standards relates to the application of a climate change factor to the design rainfall. This is set out on the following government website: https://www.gov.uk/guidance/flood- risk-assessments-climate-change-allowances and requires a 40% increase to the peak design rainfall event.
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5. Conclusions The development has an existing planning approval and the recently-granted NMA 2020 for which the proposed mitigations will address the updates that have been made in the intervening years to the relevant planning policies and guidelines. The Environmental Statement Reports of 2006 & 2007 are considered to remain valid and it is not considered to be necessary to undertake any revision to those reports. As stated in Section 4 above, relating to the design associated with the surface water run-off and the surface water drainage strategy, this should include for the new climate change allowance of 40% for rainfall intensity. This may require larger attenuation to be provided for the surface water discharging from the site via the gravity/ditch course system, but the overall strategy is still considered appropriate.
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National Grid Grain LNG Limited Grain LNG Phase 3B
APPENDIX 1.5: SOILS, GROUNDWATER AND CONTAMINATION
TECHNICAL NOTE
ES Volume 2: Technical Appendices
Technical Note
Project: Isle of Grain - Grain LNG Expansion Northern Zone Project (planning application ref. MC2007/1683, amendment of MC2006/1428)
Subject: Review of chapters on Soil Conditions, Groundwater and Contamination within the Environmental Statement (2006 and 2007)
Author: Atkins
Date: 27/11/2020 Project No.: 5186422
Distribution: Andy Collins Representing: National Grid GLNG James Bumphrey Greengage
Document history Revision Purpose description Originated Checked Reviewed Authorised Date Rev 1.0 Draft HM LB LB LH 30/10/20 Rev 2.0 Final HM LB LB LH 10/11/20 Rev 3.0 Final HM LB LB LH 11/11/20 Rev 4.0 Final HM LH LH LH 25/11/20 Rev 5.0 Final HM LH LH LH 27/11/20
Client signoff Client National Grid Project Isle of Grain - Grain LNG Expansion Northern Zone Project (planning application ref. MC2007/1683, amendment of MC2006/1428) Project No. 5186422
Client signature / date
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1. Introduction Atkins Limited (Atkins) has been instructed by National Grid Grain LNG Limited (GLNG) to review and appraise existing information relating to soils, groundwater and contamination for two liquefied natural gas (LNG) storage tanks at the Grain LNG Importation Facility located on the Isle of Grain, Kent (“the Site”). This review has been prepared to support planning condition discharge associated with the existing planning permission as part of an updated Environmental Statement (ES) being coordinated by Greengage Environmental Limited (Greengage). A 2006 ES [1] and 2007 ES update [2] were originally prepared in support of the development, which included the construction of two LNG storage tanks, associated processing equipment, a jetty and other related infrastructure (Planning Ref: MC2006/1428, amended to MC2007/1683). One of LNG storage tanks (known as Phase 3A) has now been constructed, with GLNG currently progressing works in preparation for the construction of the second tank (known as Phase 3B). Given the time that has passed since the original ESs were produced, Atkins have been instructed to review the ES and subsequent site assessments to determine if baseline conditions and proposed mitigation measures are still applicable and confirm, or otherwise, that no significant soils, groundwater or contamination impacts are anticipated in relation to construction of the Phase 3B storage tank. Given that the Phase 3A tank and associated infrastructure has already been constructed and has been operational since 2010, the Phase 3A area has been considered as part of the updated baseline. The methodology adopted herein has included the following: 1. Review the historic planning documentation: a. ES 2006 [1] Soil Conditions, Groundwater & Contamination chapter, b. ES 2007 [2] Soils, Groundwater & Contamination chapter. 2. Research the following elements for the Technical Notes: a. review the 2006/7 ESs and current Site Baseline and identify changes; b. review of any pertinent legislative changes since 2006/7, along with changes to Technical Design Guides, Standards and Policy which may impact on the ES; c. review of known onsite “works” undertaken from 2006/7 to the present day; and their potential impact to the ES; and d. review of site ground conditions information obtained since 2006/7. The majority of the original proposed works under Planning Ref: MC2007/1683, amendment of MC2006/1428 have now been completed. As such, this technical note focuses only on the Phase 3B area and associated laydown area. In Atkins’ assessment of the 2007 ES [2] submission, no updates to the soil conditions, groundwater and contamination chapter were noted compared to the 2006 ES [1]. Therefore, Atkins’ review of historical findings focuses on the 2006 ES [1]. 2. Ground Investigation Works 2006 – Present Further to the review of the 2006 ES, Atkins also reviewed the following documents: Isle of Grain Land Contamination Assessment Final Interpretative Report, Atkins (2008) [3], produced to provide a generic land contamination assessment of potential risks to human health and controlled water receptors associated with the NGPL site in its current usage and with regard to an industrial/commercial redevelopment scenario; and Factual Report on Ground Investigation (Phase 4 (now known as Phase 3B)), Soil Mechanics (2010) [4], produced to provide geotechnical information for the Phase 3B LNG Storage Tank. 3. Legislation and Planning Policy Context Since the 2006 ES [1], on a national scale: the Contaminated Land (England) Regulations (2006) and the Contaminated Land (England) (Amendment) Regulations 2012 have replaced the Contaminated Land (England) Regulations (2000);
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the Water Environment (Water Framework Directive) (England and Wales) Regulations 2017 are now implemented; and The National Planning Policy Framework [5] was released in 2012 and updated in 2019. The National Planning Policy Framework sets out how local planning policies must be implemented from a ground conditions and water quality perspective. As detailed in the 2006 ES [1], Part IIA of the Environmental Protection Act 1990 provides the legislative framework within which land quality issues associated with the site should be assessed. The national legislative and policy changes identified above are not considered to significantly impact the findings of the 2006 ES [1], in relation to the soils, groundwater and contamination assessment. On a regional and local level, no policy changes are considered to impact the findings of the original ES. The Medway Local Plan (2003) [6] detailed in the 2006 ES [1] is still valid. A new local plan is being developed and is scheduled for adoption in 2022. It is not anticipated that the new local plan will affect the findings of the 2006 ES. 4. Assessment Methodology Since 2006, the assessment area has been further investigated by Atkins providing additional site-specific data. The Isle of Grain Land Contamination Assessment Final Interpretative Report, Atkins (2008) [3] has been reviewed to determine if the site baseline set out in the 2006 ES [1] adequately characterises the site. The Soil Mechanics Factual Report on Ground Investigation (Phase 4 (now known as Phase 3B)) [4], which had a geotechnical focus, was also reviewed to provide additional site-specific detail on geological conditions. Atkins are not aware of any other site investigation pertinent to the application site. The Atkins ground investigation was completed in 2007 and comprised 39 No. mechanically excavated trial pits and 3 No. boreholes progressed across the assessment area. Land contamination was assessed based on a range of ground investigation data including soil samples, ground gas, groundwater samples and site investigation logs. As part of the assessment, the site was split into smaller land parcels; the application site falls within Area 4. Both human health and controlled waters risk assessments were undertaken for Area 4. It should be noted that historical risk assessments, including those discussed in the 2006 ES [1] and 2008 site investigation report [3], were undertaken based on the relevant guidance at the time. Since 2006, a number of guidelines have been updated and amended. Land Contamination: Risk Management [7], published in 2020 sets out the current framework under which the risks posed by land contamination should be assessed. The soil screening values used to assess the risks posed by contaminated soils to human health [3] were based on guidance set out in Contaminated Land Reports 7-10 [8] [9] [10]. Since 2008, soil assessment guidelines have been updated [11] [12] and as such, soil screening values used in the human health risk assessment [3] may not be current. Ground gas guidance used in the human health risk assessment [3] has also been updated since 2008, with the replacement of CIRIA 659 [13] with CIRIA 665 [14] and the introduction of the Ground Gas Handbook. However, these updates are not considered to have an impact on the outcome of the assessment. The water screening values used to assess the risks posed by contaminated groundwater to controlled waters [3] were based on historical water quality standards. Since 2008, environmental quality standards (2015) and drinking water standards (2016) have been published and as such, water quality standards used in the 2008 controlled waters risk assessment may not be current. 5. Baseline Conditions In general, the baseline conditions set out in the 2006 ES [1] are considered to remain valid. This section provides a summary of key findings since the ES was produced. Geological logs from the 2007 ground investigation [3] show most of the assessment area is underlain by Made Ground, Alluvial Clay and London Clay (where excavations are sufficiently deep to penetrate the London Clay). Occasionally River Terrace Deposits overly London Clay and Made Ground is absent. A 2010 Soil Mechanics ground investigation included progression of 6 No. boreholes on the proposed site of the LNG storage tank. The geological logs consistently note Made Ground at surface, underlain by Alluvium followed by River Terrace Deposits then London Clay. The deepest borehole extended 70 m bgl, encountering London Clay at approximately 12 m bgl and not fully penetrating it (thickness of over 58 m).
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The findings of the 2007 and 2010 ground investigations generally align with the geological sequence laid out in the 2006 ES [1]. The ES notes that groundwater strikes were encountered 1-2 m below ground level (bgl). In Atkins (2008) [3], groundwater was recorded between 0.8 and 2.6 m bgl, associated with the River Terrace Deposits or perched water within Made Ground and Alluvium. Since the ES was written, aquifer designations that are more consistent with Water Framework Directive have been introduced. As such, the Minor Aquifer classification designated to the Alluvium, River Terrace Deposits and Lambeth Group changes to a Secondary Aquifer classification, and the Major Aquifer classification designated to the Chalk changes to Principal Aquifer. These changes have no impact to the risk designations assigned in the ES and are changes in terminology only. The human health risk assessment completed by Atkins [3] concluded that statistically representative contaminant concentrations calculated for Area 4 were generally below human health commercial/industrial generic assessment criteria. It indicated that any remediation works required for protection of human health under the site’s current use would be confined to the hotspot area to the southeast of the assessment area in the vicinity of TP3118 (see Figure 1 below). Elevated soil free cyanide concentrations were noted at this location. Figure 1 – Extract from site location plan [3] (see TP3118 circled in orange)
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General ground gas concentrations detected in Area 4 were indicative of a Characteristic Situation 1 indicating that no remedial works or gas protection measures would be required. As part of the 2007 ground investigation [3], near surface asbestos was found extensively across Area 4, including nine locations within the assessment area (TP3074, TP3096, TP3101, TP3090, TP3075, TP3094, TP3104, TP1311 and TP3113). The controlled waters risk assessment in Atkins (2008) [3] found concentrations of metals, inorganic compounds and hydrocarbon compounds exceeded groundwater assessment criteria in leachate and groundwater samples collected from Area 4, including the assessment area. No new sources, pathways or receptors beyond those detailed in the 2006 ES [1] are considered to exist. 6. Potential Impacts In general, the potential construction phase impacts set out in the 2006 ES [1] are considered to remain valid. These include impacts to: groundwater and surface water from Made Ground / historical activity on site (minor negative significance); construction workers from Made Ground / historical activity on site (minor to major negative significance); adjacent sites / adjacent site users from Made Ground / historical activity on site (negligible to minor negative significance); flora and fauna from Made Ground / historical activity on site (minor negative to major negative significance); and current site users and construction workers from landgas (now referred to as ground gas). This impact was considered to have minor negative significance to current site users and construction workers in the 2006 ES [1]. Based on the findings of the Atkins site investigation [6] it is considered that a negligible significance designation is more appropriate. Operational phase impacts set out in the 2006 ES [1] also remain valid. These include impacts to: groundwater and surface water from storage or use of maintenance materials (negligible or minor negative significance); future site workers from storage or use of maintenance materials (negligible significance); and future site workers from ground gas (negligible significance). 7. Mitigation Measures In the 2006 ES [1], further ground investigation was recommended to better characterise the site. This will ensure all the risks are fully characterised and any unacceptable risks can be mitigated. It is still considered that a targeted ground investigation may be requested by the Local Authority to supplement the data collected and presented during previous phases of work, focussing on areas of the site where intrusive work is proposed, however sufficient ground investigation data is likely to be available through previous phases of work assuming this can now be presented in an updated assessment. Prior to construction, production of a construction environmental management plan (CEMP) will also be prepared in accordance with best practice; although this is not a specific planning requirement. The CEMP will be designed to ensure construction complies with the requirements of: Environmental legislation; The Environment Agency; Medway Council Environmental Health Department; and Planning permissions and associated environmental conditions. All mitigation measures detailed in the 2006 ES [1] are still considered valid. 8. Residual Effects In the 2006 ES [1] it was stated that any residual effects at the application site relating to soil and groundwater quality will be subject to strict environmental risk assessment in line with risk modelling (CLEA and EA R&D
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P20) and agreed with the EA and / or the Medway Council. Consequently, residual impacts were considered to be acceptable within the context of the proposals as a commercial development. The context to the management of any residual effects under the current Planning regime has not changed significantly and therefore this section of the ES is still considered valid. 9. Conclusions With the exception of changes to the legislative and Planning policy framework since the 2006 ES [1] and 2007 ES update [2] no significant changes to the baseline conditions, potential impacts or mitigation measures are considered to have occurred at the time of preparing this technical note. It is therefore considered that the ES does not need to be updated and the overall mitigation strategy for the continuation of the consented works is still appropriate.
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References
[1] Environmental Perspectives, “Grain LNG Phase 3 Expansion, Environmental Impact Assessment, Volume 1 Environmental Statement,” National Grid, 2006. [2] Environmental Perspectives, “Environmental Statement, Grain LNG Expansion Project Northern Zone Update,” National Grid, 2007. [3] Atkins, “Isle of Grain Land Contamination Assessment Final Interpretative Report,” National Grid Property Ltd, 2008. [4] Soil Mechanics, “Factual Report on Ground Investigation (Phase 4),” National Grid, 2010. [5] Ministry of Housing, Communities and Local Government, “National Planning Policy Framework,” Ministry of Housing, Communities and Local Government, 2019. [6] Medway Council, “Medway Local Plan,” Medway Council, 2003. [7] Environment Agency, “Land Contamination: Risk Management,” Environment Agency, 2020. [8] DEFRA and Environment Agency, “Assessment of Risks To Human Health from Land Contamination: An Overview of the Development of the Guideline Values and related research, Report CLR7,” Environment Agency, 2002. [9] DEFRA and Environment Agency, “Priority Contaminants Report, Report CLR8.,” Environment Agency, 2002. [10] DEFRA and Environment Agency, “The Contaminated Land Exposure Assessment Model (CLEA): Technical Basis and Algorithms, Report CLR10,” Environment Agency, 2002. [11] Environment Agency, “Updated technical background to the CLEA model Science Report: SC050021/SR3,” 2009. [12] DEFRA, “Development of Category 4 Screening Levels for Assessment of Land Affected by Contamination,” 2013. [13] CIRIA, “CIRIA Report 659. Assessing Risks Posed by Hazardous Ground Gases to Buildings.,” 2006. [14] CIRIA, “Assessing risks posed by hazardous ground gases to buildings (C665),” 2007. [15] Greengage, “Grain LNG Phase 4 ES Briefing Note,” 2020. [16] Atkins, “Isle of Grain Former BP Oil Refinery Landfill Environmental Liability Assessment,” National Grid Property Limited, 2008. [17] Atkins, “Isle of Grain Controlled Waters Detailed Quantitative Risk Assessment,” National Grid Property Ltd, 2008.
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National Grid Grain LNG Limited Grain LNG Phase 3B
APPENDIX 1.6: INFORMAL SCOPING REPORT
ES Volume 2: Technical Appendices
National Grid Grain LNG Limited LNG Grid NationalGrain
Grain Grain LNG 3B Phase Environmental Statement Informal Scoping Report, November 2020 November Report, Scoping Informal Statement Environmental National Grid Grain LNG Limited Grain LNG Phase 3B
QA
Grain LNG Phase 3B – Environmental Statement Informal Scoping Report
Issue/Revision: Draft Final
Date: November 2020 November 2020
Comments:
Prepared by: Nina Cooper Nina Cooper
Signature:
Authorised by: James Bumphrey James Bumphrey
Signature:
File Reference: 551468NC21JUL20D01_EIA_Scop 551468NC21JUL20F01_EIA_Scop
EIA Scoping Report ii
National Grid Grain LNG Limited Grain LNG Phase 3B
CONTENTS
1.0 INTRODUCTION 1
2.0 DEVELOPMENT CONTEXT 7
3.0 SCOPE OF ES 15
4.0 SCOPE OF TECHNICAL ASSESSMENTS 33
FIGURE 1 SITE LOCATION PLAN
REFERENCES
EIA Scoping Report iii
National Grid Grain LNG Limited Grain LNG Phase 3B
1.0 INTRODUCTION
1.1 This Environmental Statement (ES) has been prepared on behalf of National Grid Grain LNG Limited (the ‘applicant’) in support of the preparation of condition discharge documents associated with an existing permission for a Development known as Phase 3 (Planning Ref: MC2007/1683, amendment of MC2006/1428) at the Grain liquefied natural gas (LNG) importation facility. This is an informal scoping report which sets out the scope for the ES and the reasoning behind the approach taken.
1.2 A Non Material Amendment (NMA) has been submitted and approved (Ref: MC/20/2644) to formalise the phasing of Phase 3 which predominately comprises two LNG storage tanks, permitted under permission MC2007/1683, at the Grain LNG Importation facility. The phases are known as Phase 3A and Phase 3B. Phase 3A was completed in 2010 with work due to commence on Phase 3B in 2021.
1.3 The ES Informal Scoping report has been prepared on behalf of National Grid Grain LNG Limited (the ‘applicant’).
1.4 The applicant is a wholly owned subsidiary of National Grid, an international utility company whose core business is the management of large and complex energy networks across England and Wales. The applicant owns and operates the Grain LNG importation facility at the Isle of Grain, Kent, which is used for the importation of LNG.
1.5 ESs were previously prepared in support of applications MC2006/1428 (the 2006 ES) and MC2007/1683 (the 2007 ES1). These permissions are hereafter known in this ES as ‘the First Permission’ (Ref: MC2006/1428) and ‘the Second Permission’ (Ref: MC2007/1683). The 2006 ES was prepared in support of a wider development which included the two liquified LNG storage tanks in an area known as the ‘Northern Zone’. The arrangement of these was amended in the Second Permission with the 2007 ES prepared in support of this. The 2007 ES largely comprised a review undertaken by relevant technical consultants confirming that the findings of the 2006 ES remained valid in light of the amended arrangements of the tank, however updated assessments were undertaken where relevant.
1.6 Given the time since Phase 3A was completed, and the 2006 and 2007 ESs were prepared, it is considered that the baseline and methodology used for these will now likely be out of date. An updated ES will therefore be produced utilising updated baseline and assessment methodology to support the submission of condition discharge documentation required for Phase 3B. As such this is considered to be other environmental information with regards to Regulation 25 of the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, and an EIA is being undertaken with an ES submitted accordingly.
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1.7 In addition to an updated baseline and methodology, the ES will consider relevant new environmental topics introduced as part of the Town and Country Planning (Environmental Impact Assessment) Regulations 2017. The 2006 ES and 2007 ES were produced under the previous EIA Regulations (Town and Country Planning (Environmental Impact Assessment) Regulations 1999).
1.8 The EIA will also consider additional cumulative schemes that have emerged since the production of the 2006 ES and 2007 ES.
1.9 The site occupies approximately 26 hectares (ha) and is located at the existing Grain LNG Importation Facility on the north bank of the Medway Estuary on the Isle of Grain, Kent.
1.10 The assessment area for the EIA described as ‘the site’, is the same as that assessed in the 2007 ES and comprises the areas shown in Figure 1 at the end of this report and Figure 1.1 below:
• The area of the Development consented under the Second Permission (MC2007/1683); the consented redline boundary; and
• An area of temporary construction laydown area shown edged blue, which was initially consented as part of the First Permission (MC2006/1428).
Figure 1.1 Site location plan
Note: Redline boundary shown in red, temporary construction laydown area in blue.
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THE EIA REGULATIONS AND NEED FOR AN ENVIRONMENTAL IMPACT ASSESSMENT
The EIA Regulations
1.11 EIA is a systematic process during which potential significant environmental impacts from a development project are identified, assessed and the scope for minimising potential adverse impacts are presented to the relevant decision maker (the 'competent authority') within an ES accompanying a planning application.
1.12 The revised EIA Directive (2014/52/EU), adopted by the European Parliament in 2014, was transposed into UK law through the Town and Country Planning (Environmental Impact Assessment) (England and Wales) Regulations 2017 (the 'EIA Regulations 2017') on 16th May 2017. These regulations replaced the Town and Country Planning (Environmental Impact Assessment) (England and Wales) Regulations 2011.
1.13 The updated ES will present findings from an Environmental Impact Assessment (‘EIA’) that has been carried out in accordance with the Town and Country Planning (Environmental Impact Assessment) Regulations 2017 (EIA Regulations 2017), to assess the impacts of the Development. The 2006 ES and 2007 ESs were produced under the previous EIA Regulations (Town and Country Planning (Environmental Impact Assessment) Regulations 1999). The application to discharge is a subsequent application for the EIA Regulations and therefore up to date information is being provided notwithstanding the transitional provisions in Regulation 76 of the EIA Regulations 2017.
1.14 Regulation 4(2) of the EIA Regulations 2017 covers EIA process and states:
‘The EIA must identify, describe and assess in an appropriate manner, in light of each individual case, the direct and indirect significant effects of the proposed development on the following factors—
(a) population and human health;
(b) biodiversity, with particular attention to species and habitats protected under Directive 92/43/EEC(1) and Directive 2009/147/EC(2);
(c) land, soil, water, air and climate;
(d) material assets, cultural heritage and the landscape;
(e) the interaction between the factors referred to in sub-paragraphs (a) to (d).’
1.15 Schedule 4 of the EIA Regulations 2017 sets out the information for inclusion within an ES. This is summarised in the table below and is to be included within the updated ES.
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Table 1.1 Legal Minimum Requirements for the Contents of an ES
Requirement of Regulations 18(3) and Schedule 4 of the 2017 EIA Regulations for the inclusion in Environmental Statements
Regulation 18(3)
(a) A description of the proposed development comprising information on the site, design, size and other relevant features of the development.
(b) A description of the likely significant effects of the proposed development on the environment.
(c) A description of any features of the proposed development, or measures envisaged in order to avoid, prevent or reduce and, if possible, offset likely significant adverse effects on the environment.
(d) A description of the reasonable alternatives studied by the developer, which are relevant to the proposed development and its specific characteristics, and an indication of the main reasons for the options chosen, taking into account the effects of the development on the environment.
(e) A non-technical summary of the information referred to in sub-paragraphs (a) to (d).
(f) Any additional information specified in Schedule 4 relevant to the specific characteristics of the particular development or type of development and to the environmental features likely to be significantly affected.
Schedule 4
1 A description of the development, including in particular: (a)a description of the location of the development; (b)a description of the physical characteristics of the whole development, including, where relevant, requisite demolition works, and the land-use requirements during the construction and operational phases; (c)a description of the main characteristics of the operational phase of the development (in particular any production process), for instance, energy demand and energy used, nature and quantity of the materials and natural resources (including water, land, soil and biodiversity) used; (d)an estimate, by type and quantity, of expected residues and emissions (such as water, air, soil and subsoil pollution, noise, vibration, light, heat, radiation and quantities and types of waste produced during the construction and operation phases.
2 A description of the reasonable alternatives (for example in terms of development design, technology, location, size and scale) studied by the developer, which are relevant to the proposed project and its specific characteristics, and an indication of the main reasons for selecting the chosen option, including a comparison of the environmental effects.
3 A description of the relevant aspects of the current state of the environment (baseline scenario) and an outline of the likely evolution thereof without
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Requirement of Regulations 18(3) and Schedule 4 of the 2017 EIA Regulations for the inclusion in Environmental Statements implementation of the development as far as natural changes from the baseline scenario can be assessed with reasonable effort on the basis of the availability of environmental information and scientific knowledge.
4 A description of the factors specified in regulation 4(2) likely to be significantly affected by the development: population, human health, biodiversity (for example fauna and flora), land (for example land take), soil (for example organic matter, erosion, compaction, sealing), water (for example hydromorphological changes, quantity and quality), air, climate (for example greenhouse gas emissions, impacts relevant to adaptation), material assets, cultural heritage, including architectural and archaeological aspects, and landscape.
5 A description of the likely significant effects of the development on the environment resulting from, inter alia:
(a) the construction and existence of the development, including, where relevant, demolition works;
(b) the use of natural resources, in particular land, soil, water and biodiversity, considering as far as possible the sustainable availability of these resources;
(c) the emission of pollutants, noise, vibration, light, heat and radiation, the creation of nuisances, and the disposal and recovery of waste;
(d) the risks to human health, cultural heritage or the environment (for example due to accidents or disasters);
(e) the cumulation of effects with other existing and/or approved projects, taking into account any existing environmental problems relating to areas of particular environmental importance likely to be affected or the use of natural resources;
(f) the impact of the project on climate (for example the nature and magnitude of greenhouse gas emissions) and the vulnerability of the project to climate change;
(g) the technologies and the substances used.
The description of the likely significant effects on the factors specified in regulation 4(2) should cover the direct effects and any indirect, secondary, cumulative, transboundary, short-term, medium-term and long-term, permanent and temporary, positive and negative effects of the development. This description should take into account the environmental protection objectives established at Union or Member State level which are relevant to the project, including in particular those established under Council Directive 92/43/EEC(1) and Directive 2009/147/EC(2).
6 A description of the forecasting methods or evidence, used to identify and assess the significant effects on the environment, including details of difficulties (for example technical deficiencies or lack of knowledge) encountered compiling the required information and the main uncertainties involved.
7 A description of the measures envisaged to avoid, prevent, reduce or, if possible, offset any identified significant adverse effects on the environment and, where appropriate, of any proposed monitoring arrangements (for example
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Requirement of Regulations 18(3) and Schedule 4 of the 2017 EIA Regulations for the inclusion in Environmental Statements the preparation of a post-project analysis). That description should explain the extent, to which significant adverse effects on the environment are avoided, prevented, reduced or offset, and should cover both the construction and operational phases.
8 A description of the expected significant adverse effects of the development on the environment deriving from the vulnerability of the development to risks of major accidents and/or disasters which are relevant to the project concerned. Relevant information available and obtained through risk assessments pursuant to EU legislation such as Directive 2012/18/EU(3) of the European Parliament and of the Council or Council Directive 2009/71/Euratom(4) or UK environmental assessments may be used for this purpose provided that the requirements of this Directive are met. Where appropriate, this description should include measures envisaged to prevent or mitigate the significant adverse effects of such events on the environment and details of the preparedness for and proposed response to such emergencies.
9 A non-technical summary of the information provided under paragraphs 1 to 8.
10 A reference list detailing the sources used for the descriptions and assessments included in the environmental statement.
STRUCTURE OF THE EIA SCOPING REPORT
1.16 The remainder of this EIA Scoping Report is structured as follows:
• Section 2 provides background to the development and the context of the site;
• Section 3 details the scope of the ES, overall assessment methodology, including determination of significance; and
• Section 4 details the scope of the technical assessments.
• .
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2.0 DEVELOPMENT CONTEXT
SITE LOCATION AND SETTING
2.1 The site currently occupies approximately 26 ha and is centred on National Grid Reference TQ 868759, OS Co-ordinates 586891, 175929. The assessment area for the EIA described as ‘the site’, is the same as that assessed in the 2007 ES and comprises of the following areas:
• The area of the Development consented under the Second Permission (MC2007/1683); the consented redline boundary; and
• An area of temporary construction laydown area shown edged blue, which was initially consented as part of the First Permission (MC2006/1428).
2.2 The site sits within a larger area of land owned by National Grid Property Holdings Ltd. (the ‘Grain LNG site’), which is now used as an LNG Importation Facility. To the west of the site are the existing LNG Phase 2 storage tanks and associated infrastructure. Scrub habitat sits to the northeast with Grain Road and hardstanding to the south.
2.3 The eastern end of the Hoo Peninsula, on which the Isle of Grain is located, has a long established industrial heritage. In the wider area, located to the south of the site are Medway Power Station (1km south), Thamesport Container Terminal (1km south), Bardon Aggregates aggregate business (1.2km south) and BP Oil's aviation fuel depot (800m southwest). Located to the southeast of the site is Grain Power Station (1.1km). Further to the east lies the Medway Estuary and Marshes Special Protection Area (SPA), Ramsar Site and Site of Special Scientific Interest (SSSI) (all 1.9km away).
2.4 The land use across the Isle of Grain is predominantly agricultural. The nearest settlement to the application site is Grain village, located 1.5km to the east of the Development. The area surrounding the assessment site is flat and low-lying (generally between 3m - 5m Above Ordnance Datum – AOD). It is interspersed with creeks, marshland and low tidal flats, which form part of the South Thames Estuary 2km to the north and the Medway Estuary 1.9km to the south. The Isle of Grain is linked to the mainland by the A228 and B2001 roads, which connect to the A2 / M2 and the M25. A single track freight railway line known as the North Kent Line also serves the Isle of Grain.
2.5 A site location plan is provided at Figure 1.1 below and Figure 1 at the end of this report.
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EXISTING LNG IMPORTATION FACILITY
2.6 The existing Grain LNG Importation Facility adjacent to the site is used for the importation and processing of LNG from overseas, which supports the energy supply network of the region and the UK.
2.7 LNG is formed from Natural Gas by a super-cooling process known as ‘cryogenic cooling’. This liquefies and condenses the Natural Gas allowing its efficient transportation because the volume of liquid is less than that of the equivalent gas. LNG is transported by sea in purpose-built ships. LNG is offloaded and pumped to the LNG storage tanks and process plant by means of two existing above ground LNG transfer pipeline serving Jetty 10 and Jetty 8. LNG is stored in LNG storage tanks within the boundary of the LNG storage and processing site in the Northern Zone (see Figure 1.1). When required, LNG is pumped from the tanks and turned back into Natural Gas (through a process called “vaporisation”). It is then fed into the existing high pressure Natural Gas pipeline that connects the LNG process plant to the UK gas National Transmission System (NTS). The NTS is a system of high pressure pipelines, buried underground, that transport gas from the main coastal terminals to local distribution networks and major industrial gas consumers.
DESCRIPTION OF DEVELOPMENT
First Permission
2.8 The First Permission (Ref: MC2006/1428) was granted on 14th May 2007 for the expansion of the Grain LNG Importation Facility (referred to as the Grain LNG Phase 3 Expansion) which was supported by an ES (the '2006 ES').
2.9 The First Permission granted consent for an LNG importation storage, vaporisation and distribution facility, comprising:
• Demolition and construction of a new jetty (New Jetty 8);
• Construction of jetty approach consisting of a LNG pipe rack and vehicular access;
• Existing internal access road extended to connect vehicular deck access via a deck access ramp;
• Reinstatement by dredging of existing berth box to accommodate LNG carriers;
• Erection of equipment landwards of the existing sea wall comprising a nitrogen generator, jetty control room, security gatehouse, diesel generator and electricity sub- station;
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• Construction of pipeline to connect jetty head passing above the sea wall to the existing LNG transfer pipeline;
• Construction of two LNG storage tanks, each having a capacity of 190,000m3;
• Installation of six additional submerged combustion vaporisers;
• Provision of related infrastructure; and
• Temporary lay down area in the northern and central zones.
2.10 The following infrastructure was then constructed under the First Permission:
• Demolition and construction of a new jetty (New Jetty 8);
• Construction of jetty approach consisting of a LNG pipe rack and vehicular access;
• Existing internal access road extended to connect vehicular deck access via a deck access ramp;
• Reinstatement by dredging of existing berth box to accommodate LNG carriers;
• Erection of equipment landwards of the existing sea wall comprising jetty control room, security gatehouse, diesel generator and electricity sub-station; and
• Construction of pipeline to connect jetty head passing above the sea wall to the existing LNG transfer pipeline.
Second Permission
2.11 The Second Permission (Ref: MC2007/1683) was then granted on 21st December 2007 to reflect a new arrangement of the LNG storage tanks and associated process plant (known as the ‘Northern Zone Amendment’) which was supported by an ES (the ‘2007 ES’). This Second Permission allowed for the relocation of the consented Phase 3 LNG storage tanks and associated equipment approximately 40m to the south east from their permitted location, and change the orientation of the vaporisation and process equipment by 90 degrees, plus the addition of a submerged combustion vaporiser (SCV) hot water sump and drainage water holding pond.
2.12 The Second Permission, known as the Phase 3 development, therefore comprised of the following:
• Construction of two LNG storage tanks, each having a capacity of 190,000m3;
• Installation of six additional submerged combustion vaporisers;
• Provision of related infrastructure including:
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i. Pipe racks connecting the new tanks to the existing site racks;
ii. Unloading line from the closest point to the tanks;
iii. External tank pumps;
iv. Boil off gas compressors;
v. An impounding basin;
vi. Flow meters to monitor volume of natural gas;
vii. Power connections for generated power;
viii. Provision of internal site access roads;
ix. 2.5m palisade security fence topped with barbed wire surrounding the new facilities and contiguous with the existing boundary fence;
x. A vent stack;
xi. A compressor shelter;
xii. A holding pond; and
xiii. An SCV circulation water tank.
Non Material Amendment
2.13 A NMA has been submitted and approved (Ref: MC/20/2644) to formalise the phasing of Phase 3 permitted under the Second Permission. Phase 3A was completed in 2010 with work due to commence on Phase 3B in 2021.
Development
2.14 The Development consists of the Phase 3 Development identified under the Second Permission and amended under the NMA. The Development therefore consists of Phase 3A and Phase 3B.
2.15 The elements of the above construction in Phases 3A and Phase 3B are set out in the table below:
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Table 2.1 Infrastructure for Phase 3A and Phase 3B
Phase 3A Phase 3B
Construction of one LNG storage tank with a Construction of one LNG storage tank with a capacity of 190,000m3 capacity of 190,000m3
Installation of four submerged combustion Installation of two submerged combustion vaporisers vaporisers
Provision of related infrastructure including: Provision of related infrastructure including:
• Pipe racks connecting the new tank to the Two external tank pumps. existing site racks; • Unloading line from the closest point to the tanks; • Four external tank pumps; • Boil off gas compressors; • An impounding basin; • Flow meters to monitor volume of natural gas; • Power connections for generated power; • Provision of internal site access roads; • 2.5m palisade security fence topped with barbed wire surrounding the new facilities and contiguous with the existing boundary fence; • A vent stack; • A compressor shelter; • A holding pond; and • An SCV circulation water tank.
2.16 A phasing plan is provided at Figure 2.1 below.
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Figure 2.1 Phasing Plan
Key Phase 3A Phase 3B
CONSTRUCTION
Programme
2.17 The construction of Phase 3A was completed in 2010.
2.18 The current indicative construction programme for the Phase 3B development is set out in Table 2.2 below.
Table 2.2 Summary Construction Programme
Stage Start End Length
Ground Preparation and December 9 months April 2021 Piling 2021
Outer concrete wall and May to 2 to 6 months March 2022 concrete roof construction August 2022
Inner tank and tank top 24 months June 2022 June 2024 equipment
Hydrotesting, drying and 5 months December purging of the tank ready June 2024 2024 for commissioning
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Methodology
2.19 The construction of the Phase 3B development will comprise:
• Piling the base structure;
• Casting the tank base onto the piles;
• Casting the outer concrete wall;
• Installation of the bottom liner, insulation and screed;
• Construction of the steel roof and inner tank suspended deck;
• Construction of concrete compression rings; and concreting of lower haunch;
• Installation of roof temporary support;
• Roof sectors erection;
• Raising the inner roof and suspended deck to the top of the outer wall and fixing;
• Pouring of upper haunch (transition between wall and roof);
• Nozzle erection, ring beam main concrete pouring and corner protection starting;
• Pre-stressing and roof steel reinforcement fixing;
• Wall liner/corner protection erection;
• Casting the concrete outer roof over the inner roof;
• Installation of carbon steel liners;
• Construction of the inner tank: Inner tank annular plates erection, shell courses;
• Installation of the inner tank infrastructure (excluding LNG pumps);
• The installation of ancillary infrastructure;
• Preparation for hydraulic test;
• Hydrostatic test;
• Resilient blanket installation;
• Pneumatic and vacuum tests;
• Perlite installation;
• Insulation installation on suspended deck;
• Filling the interspace between the inner and outer tank with insulation;
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• External piping, structures, jib crane and equipment;
• Tank electrical and instrumentation works;
• Drying, nitrogen purging and cool down;
• The installation of vaporisers and other non-tank infrastructure; and
• Tank testing and commissioning.
PLANNING CONTEXT
2.20 The following development policies have been identified as being of particular relevance to the site and Development. The policies will be discussed in further detail within the individual technical chapters of the ES where relevant.
National Policy
2.21 National Planning Policy Framework (NPPF)1 2019 Paragraphs/Sections:
• Paragraph 8 – Overarching objectives for achieving sustainable development;
• Paragraph 11 – Presumption in favour of development;
• Section 2 – Achieving sustainable development;
• Section 4 – Decision-making;
• Section 6 – Building a strong, competitive economy;
• Section 9 – Promoting sustainable transport;
• Section 14 – Meeting the challenge of climate change, flooding and coastal change.
2.22 The Planning Practice Guidance (PPG)2 provides important information for any user of the planning system, linking the Framework with necessary guidance.
Local Policy
2.23 The following documentation from Medway Council and Kent County Council will be referred to when preparing the ES:
• Medway Local Plan (2003)3;
• Emerging Medway Local Plan Pre-Consultation Draft (2018)4;
• Medway Local Transport Plan (2011)5; and
• Kent Local Transport Plan 4 (2017)6.
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3.0 SCOPE OF ES
ENVIRONMENTAL TOPICS NOT BEING ASSESSED
3.1 The process of scoping determines the topics or areas of potential likely impacts to be addressed and the geographical area and timeframe over which they will be considered. It sets out the methods to be used to determine the likely significant environmental effects that will arise as a result of the operation of the Development. The scoping process also enables certain potential impacts to be scoped out as not being likely to give rise to significant environmental effects.
3.2 To assist with determining the scope of this updated EIA, a review has been undertaken of the scope of the 2007 ES as this ES focussed specifically on the Phase 3 area. Given that a significant amount of mitigation has already been implemented, to enable and as part of the construction and subsequent operation of Phase 3A, it was considered that there were likely to be topics that do not require further detailed assessment as part of this updated EIA. A review was therefore undertaken by relevant technical consultants to support this (this will be included as appendices to the ES). In large part this is because, the part of the Development (that gives rise the potential for such effects by topic) have already been carried out and/or the balance of the Development in Phase 3B is such (by scale, nature and/or extent) is not expected to change the outcome of the previous assessment in the 2007 ES. In relation to topics that are not updated, a technical note of the effects associated with Phase 3B is to be produced and appended to the ES.
3.3 A review was also undertaken of environmental topics introduced in the EIA Regulations 2017 that were not previously assessed.
3.4 The findings of this review are presented in Table 3.1 below.
Table 3.1 Scope for this Updated EIA
Topic Scoped In/ Justification Out for further assessment Topics Included in 2007 EIA
Ecology Out As part of the Phase 3A development, extensive ecological mitigation was implemented in accordance with Condition 23 and 24 of the Second Permission. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for ecology.
The current baseline condition for the Phase 3B area and construction laydown area is reflective of site / habitat
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clearance and ecological mitigation undertaken as part of Phase 3A pursuant to the Second Permission which created the development platform and lay-down areas for Phase 3B.
Mitigation required under the 2007 ES is secured through existing planning conditions which has largely been implemented as part of Phase 3A. As a result of the Phase 3A works, the site is now subject to regular maintenance and fenced to prevent ingress of Great Crested Newts and reptiles in particular.
Based on the updated baseline, the Phase 3B area and construction laydown area is of limited intrinsic ecological value, being dominated by recolonising ground and hardstanding. Construction laydown area has some value in the context of it being a component part of the BAP habitat ‘Open Mosaic on Previously Developed Land’ however, it is a very small part of a wider area of previously developed land.
In relation to faunal species, it is considered that the Phase 3B area and construction laydown area provides very little opportunity for protected or notable species based on updated ecological surveys carried out in 2020.
It is considered that the potential for ecological impacts associated with Phase 3B will not be likely significant and no further detailed EIA assessment of the Phase 3B area is necessary. A technical statement has been produced to confirm the updated baseline and mitigation for the Phase 3B area and construction laydown area, and concludes that no significant ecological effects are anticipated from the works associated with Phase 3B.
Matters concerning European designated sites (and Ramsar sites) and the associated consideration of Appropriate Assessment are considered to be separate to EIA. This has will be addressed in detail in an appendix to the ES for information.
Landscape In The Phase 3A development was built in accordance with and Visual Condition 2 and 3 of the Second Permission. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Landscape and Visual.
The Phase 3B development will have significant landscape and visual impacts as a result of the size of the Phase 3B tank, the flat topography of the surrounding landscape and the presence of nearby landscape and visual receptors.
These will be assessed in Chapter 5.0 Landscape and Visual of the ES based on the updated baseline.
Archaeology Out Given that all construction works for Phase 3A have now been undertaken, no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for archaeology.
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A preliminary appraisal of the site and surroundings indicates that the site does not contain any designated or non- designated heritage assets. The site is located on the Hoo Peninsula which was the subject of an in-depth study by Historic England (then English Heritage) to investigate the agricultural, military and historic development of the peninsula.
MOLA (the consultant for Phase 3B) has carried out a number of archaeological investigations within 1km of the Phase 3B area and construction laydown which found sequences of alluvial clays and peat likely deposited 12,000 years ago. No archaeological features were found.
Given the limited potential for archaeological remains in the Phase 3B area based on the 2007 ES, the nature of the archaeological baseline and the very limited prospect of any change since the assessment in 2007, it is considered that the archaeological impacts associated with Phase 3B will not be likely significant and no further detailed EIA assessment of the Phase 3B area is necessary.
An Archaeological Desk Based Assessment has been produced which includes an updated review of desk-based information and concludes that that no significant archaeological impacts are anticipated from the works associated with Phase 3B.
Transportation In As part of the Phase 3A development, a Construction Travel and Transport Plan was implemented in accordance with Condition 22 of the Second Permission. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Transportation. The limited operational effects of traffic associated with the use of the Phase 3A development are now within the baseline.
The Phase 3B development has the potential to result in significant Transportation impacts during construction due to the volume of traffic associated with the Phase 3B development during peak construction periods.
These will be assessed in Chapter 6.0 Transportation of the ES based on the updated baseline.
Noise and In As part of the Phase 3A development, construction works and Vibration the subsequent operation of Phase 3A were undertaken in accordance with Condition 15 and Condition 17-20 of the Second Permission. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Noise and Vibration. The operational effects of noise and vibration associated with the use of the Phase 3A development are now within the baseline.
The Phase 3B development has the potential to result in significant Noise impacts during construction and operation
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due to construction traffic, construction plant noise and operational plant noise.
Vibration effects from construction activity have been scoped out of the assessment due to the relative distance between source and receivers (the nearest residential properties are more than 800 m from the site), and unlikelihood of any significant vibratory methods of construction being used on the site.
While construction vibration was previously considered in the 2007 ES, vibrational impacts in the 2007 ES only considered the nearest residential receptors to the site at Harvest Cottages which are no longer occupied.
These will be assessed in Chapter 7.0 Noise and Vibration of the ES based on the updated baseline.
Air Quality In As part of the Phase 3A development, construction works of Phase 3A were undertaken in accordance with Condition 16 and 17. Mitigation was also implemented during operation as set out in the 2007 ES and emissions were monitored under the IPPC License. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Air Quality.
The Phase 3B development has the potential to result in significant Air Quality impacts during construction, due to dust generation and exhaust emissions, as well as during operation due to exhaust emissions. The Air Quality Assessment scope has included human receptors and sensitive ecology receptors at nearby designated sites due to the location of the Development.
These will be assessed in Chapter 8.0 Air Quality of the ES based on the updated baseline.
Water Out As part of the Phase 3A development, mitigation was Resources implemented and additional monitoring carried out in accordance with Condition 6a-6c and Condition 13 of the Second Permission. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for water resources.
The principles of the surface water discharge from the site have not changed since the 2006 and 2007 ESs were prepared. There remains the two original gravity ditch systems and the pumped surface water drainage system.
However, there have been maintenance works undertaken to the pumped surface water drainage system; these were undertaken under Permitted Development rights in 2015/16. These provide the site environment with a greater protection from flooding (due to pipe bursts) and provides associated water quality protection.
The drainage systems on the Grain LNG site are designed to capture any water and through a series of interceptors
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remove any contamination before returning the water to the estuary. The resulting discharge into the estuary is under a permitting regime controlled by the Environment Agency (EA) and an existing Environmental Management Plan (EMP) is in place for the site and has been operational for over 15 years. This EMP requires ongoing monitoring of the water quality, regular submission of the water quality to the EA, and water discharge to be within water quality parameters set within the applicants permit levels.
Material encountered during excavation works for Phase 3B that has the potential to be contaminated will be disposed of in accordance with all relevant updated regulation and updated good practice (as will contaminated groundwaters), removing the potential source of contamination.
Updated best practice construction practices will be implemented for Phase 3B in accordance with a Construction Environmental Management Plan (CEMP) and relevant planning condition discharge documents for Phase 3B associated with the Second Permission.
Any residual effects associated with Phase 3B are not anticipated to be different from those identified in the 2007 ES in respect of water resources and as such no further detailed EIA Chapter is proposed in this updated ES.
A technical statement has been produced which confirms the updated baseline and mitigation for the site and concludes that no additional significant contaminated water resources are anticipated from the works associated with Phase 3B.
Soils, Ground Out As part of the Phase 3A development, mitigation was Water and implemented and additional monitoring carried out in Contamination accordance with Condition 6a-6c and Condition 13 of the Second Permission. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for soils, groundwater and contamination.
The potential soils, groundwater and contamination impacts relate primarily to the construction phase where activities, such as piling, could recreate pathways for potentially contaminated groundwater to move into the drainage ditches and system on the Grain LNG site. The drainage systems on the Grain LNG site are designed to capture any water and through a series of interceptors remove any contamination before returning the water to the estuary. The resulting discharge into the estuary is under a permitting regime controlled by the Environment Agency (EA) and an existing EMP is in place for the site and has been operational for over 15 years. This EMP requires ongoing monitoring of the water quality, regular submission of the water quality to the EA, and water discharge to be within water quality parameters set within the applicants permit levels.
Construction activities associated with the Phase 3B development will follow updated best practice construction
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practices and be implemented and in accordance with a Construction Environmental Management Plan (CEMP) and relevant planning condition discharge documents associated with the Second Permission.
Any residual effects associated with Phase 3B are not anticipated to be different from those identified in the 2007 ES in respect to soils, groundwater and contamination and as such no further detailed EIA Chapter is proposed in this updated ES.
A technical statement has been produced and will be appended to the ES which confirms the baseline and mitigation for the site, and conclude that no additional significant contaminated soils, groundwater and contamination effects are anticipated from the works associated with Phase 3B.
An updated Contaminated Land Assessment is being prepared and will be submitted for discharge of condition 6 of the Second Permission.
Socio- In As part of the Phase 3A development, mitigation set out in economic the 2007 ES was implemented in accordance with restrictions on construction worker accommodation and the operational benefits of this phase of development are still being realised as assessed as it remains in operation for the foreseeable future. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Socio-economic.
Considering the nature of the Phase 3B development, it is likely that it will have significant beneficial effects due to construction employment, operational employment and maintaining a secure supply of energy. These impacts along with consideration of the impact of employees on education services and housing provision have therefore been scoped into the assessment.
These are assessed in Chapter 9.0 Socio-economic of the ES based on the updated baseline.
Risk In The mitigation described in 2007 ES Chapter for risk (in accordance with COMAH and HSE frameworks) has continued to be implemented as part of the operation of the Phase 3A development over the last 10 years.
Due to the nature of the Development it is considered necessary to include a review of all risks during the construction of Phase 3B and operation of the Development including updated HSE and COMAH information and emergency procedures.
These are assessed in Chapter 10.0 Risk of the ES based on the updated baseline and regulatory requirements.
Topics Previously Scoped Out of 2007 ES
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Wind Out The 2007 ES stated that the Development does not Microclimate incorporate structures that are adjacent or in close proximity to residential or other sensitive receptors where they are likely to give rise to overshadowing (daylight or sunlight issues), or unwanted wind patterns.
As a result this issue was scoped out of the 2007 ES.
Changes to the baseline since the 2007 ES have not resulted in the introduction of new residential or other sensitive receptors adjacent to the Development.
Therefore, given the location of the Development, it is still considered that the height and scale of the Development will not bring about any unwanted changes to wind patterns at pedestrian level, or create any potential risks to jeopardise the creation of a safe and comfortable wind environment in the vicinity.
Therefore there are no potentially significant Wind Microclimate effects for Phase 3B even when considering updates to technical guidance.
Daylight Out The 2007 ES stated that the Development does not Sunlight incorporate structures that are adjacent or in close proximity to residential or other sensitive receptors where they are likely to give rise to overshadowing (daylight or sunlight issues), or unwanted wind patterns.
As a result this issue was scoped out of the 2007 ES.
Changes to the baseline since the 2007 ES have not resulted in the introduction of new residential or other sensitive receptors adjacent to the Development.
Therefore, given the location of the Development, is not considered likely that the Development will have a significant effect on the local daylight and sunlight conditions on any neighbouring properties and open spaces, nor will the quality of light conditions be significantly changed to any sensitive receptors nearby. This is due both to the anticipated scale of the tank and to the existing site surroundings which constitute the main control on light quality in and around the site.
Therefore there are no potentially significant Daylight Sunlight effects for Phase 3B even when considering updates to technical guidance.
Marine Out This topic was scoped out in the 2007 ES for reasons set out Transport in paragraph 1.38 which explains:
‘the scope of this ES addresses the same environmental issues that were applicable to the Phase 3 Northern Zone [in the 2006 ES]. As a consequence of the proposed Northern Zone updates not including a jetty, this ES does not however, address marine transportation, as this is not applicable to the proposed development.’
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There has been no change in circumstance and it is not considered relevant to Phase 3B for the same reasons given above.
Topics Introduced in 2017 EIA Regulations
Climate In Climate change was not previously considered as a separate Change and topic area in the previous ES’ although climate change Greenhouse impacts associated with the operation of the Phase 3 Gases development were considered in the Air Quality ES Chapter.
As a result of the EIA regulations 2017, potentially significant Climate Change and Greenhouse Gas impacts associated with Phase 3B require separate consideration. The principle of the Phase 3 development is already consented. However, as a precautionary measure as it is considered that there is the potential for significant effects associated with the Phase 3B development owing to (i)Greenhouse gas emissions during construction and operation and (ii) Climate Change resilience impacts on the Phase 3B development, an appropriate assessment of effects has been carried out. These will therefore be assessed in Chapter 11.0 Climate Change and Greenhouse Gases of the ES based on the updated baseline and regulatory requirements.
Human Health In The potential for human health impacts will be assessed as part of updated ES as part of other topic chapters within the following updated ES Chapters: • Chapter 7.0: Noise and Vibration • Chapter 8.0: Air Quality • Chapter 10.0: Risk
Waste Out Waste was not previously assessed as a separate topic chapter in the 2007 ES. The quantum of waste was not defined in the 2007 ES but its potential removal was taken into account as part of considering construction, including transportation effects of the Development in the topic chapters of the 2007 ES.
Waste may be generated through the construction phase of the Phase 3B development.
Based on updated best practice guidance on IEMA7, waste impacts are only considered significant when: • Non-hazardous and inert waste generated by the development will reduce regional landfill void capacity baseline by 1% or more; or • Hazardous waste generated by the development will reduce national landfill void capacity baseline 0.1% or more. It is not envisaged that volumes of waste will be generated of this magnitude.
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Condition 21 for a Construction Waste Management Strategy was previously discharged site wide as part of the Phase 3A works.
An updated Construction Waste Management Strategy has been prepared and is submitted for approval by the local planning authority to control Phase 3B which will be implemented during the construction phase. This will maximise reuse of waste in accordance with the waste hierarchy.
Therefore, given that mitigation will be implemented during construction and the likely low volumes of anticipated waste relative to assessment thresholds this topic has been scoped out for further assessment as it is not likely to give rise to likely significant effects associated with Phase 3B for waste.
ES TECHNICAL CHAPTERS
3.5 Following the review of the EIA scope (Error! Reference source not found.) the following s cope of technical assessments is proposed:
• Landscape and Visual;
• Transportation;
• Noise and Vibration;
• Air Quality;
• Socio-economic;
• Risk;
• Climate Change and Greenhouse Gases; and
• Cumulative Impacts.
3.6 Detailed scope for the assessments described above is provided in section 4.
GENERAL ES METHODOLOGY
Guidance Documents
3.7 In addition to the EIA Regulations 2017, the ES will be prepared with reference to currently available policy guidance and good practice, where appropriate, including:
• Online Planning Practice Guidance8;
• Guidelines for Environmental Impact Assessment9; and
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• Topic specific guidance referred to in each technical Chapter of this ES where appropriate.
Cumulative Impacts
3.8 Chapter 13.0: Cumulative Impacts of the ES will address impacts likely to result from the cumulative interaction of impacts from the Development, in addition to those arising from other developments that are either under construction, approved or likely to be approved, in the vicinity of the site.
3.9 Various criteria have been adopted for establishing the scope of the cumulative assessment of impacts from more than one development. The scope of the assessment has been guided by the screening criteria listed in Error! Reference source not found.2. In screening c umulative impacts to be included within the cumulative impact assessment, other developments under consideration must, when taken in isolation, generate an impact (positive or negative) of at least minor significance for a particular issue and, in addition meet all the following criteria in Error! Reference source not found. below.
Table 3.2 Criteria for Inclusion of Developments within Cumulative Impact Assessment
Screening Criteria
To be considered within the cumulative impact assessment other development schemes must meet the following criteria: • Generate their own residual impacts of at least minor significance; • Be likely to be constructed or operate over similar time periods; • Be spatially linked to the approved development (for example using the same local road network as the site); and • Be either consented or be the subject of applications with the relevant statutory authority in the area or be the subject of another statutory procedure.
3.10 Planning applications which have the potential for cumulative impacts to occur have been identified and these will be considered against criteria to determine their potential significance. The significance criteria identified below will be used to assess cumulative impacts.
3.11 The online planning register for the Medway has been used to identify projects that are under construction or approved within the vicinity of the site. A number of schemes identified are pending determination however, given their proximity to the Development it has been determined that these are to be included within the cumulative assessment. Further detail on methodology used is provided in Chapter 13.0.
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3.12 From this search (Completed October 2020) the following schemes have been identified:
• Gas Fired Electricity Generating Facilities, National Grid (MC/19/2870 and MC/19/2871);
• Grain Business Park (MC/09/1628 and MC/15/0702);
• Land At Thamesport Grain Road (MC/19/0299);
• Land Northeast of Kingsnorth Industrial Estate (MC2008/0370);
• Land West of Grain Road Adjoining Electricity Substation (MC/20/1047);
• Land West of Grain Road and South Of West Lane Medway Power Station (MC/19/3015); and
• Aggregate Industries UK Limited (MC/20/0554).
3.13 The cumulative schemes will supersede the cumulative schemes assessed in the 2007 ES as any cumulative schemes that have been constructed since the 2007 ES (including the Grain LNG Phase 2 Development) now form part of the baseline for each technical area and are taken into account in topic chapters in relation to the assessment of Phase 3B where an updated assessment has been provided.
Means of Assessment
3.14 For each of the environmental topic areas assessed as part of the preparation of the ES, an assessment will be made in relation to the relative significance of the likely environmental effects identified. These will be carried out with reference to definitive standards and legislation, where available. Where it not possible to quantify effects, qualitative assessments will be carried out, based on available knowledge and professional judgement.
3.15 Baseline conditions, including the sensitivity and importance of those environmental aspects likely to be significantly affected by the Development, are determined to provide a context for the analysis. The baseline condition establishes a benchmark for impact prediction. Any change from the baseline informs the magnitude of the potential impact and its significance.
3.16 For the environmental elements under detailed consideration within the ES, the current (Q3/Q4 2020 unless otherwise stated) baseline conditions will be established using a combination of desk-top studies (drawing on published databases, maps, and reports, survey techniques and monitoring) and surveys, where relevant. The specific methods employed to record the baseline conditions will be detailed within the corresponding chapters of the ES.
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Impact Prediction and Significance Criteria
3.17 Schedule 4 of the EIA Regulations refers to describing:
‘likely significant effects on the factors specified in regulation 4(2) should cover the direct effects and any indirect, secondary, cumulative, transboundary, short-term, medium-term and long-term, permanent and temporary, positive and negative effects of the development...’
3.18 The significance of predicted effects will be determined with reference to assessment criteria for each environmental topic considered.
3.19 The significance of effects is assessed, taking into consideration a range of criteria, including:
• Performance against environmental quality standards;
• Relationships with international, national and local planning policy;
• Sensitivity of the receptor;
• Reversibility and duration (short, medium, long-term) of the impact;
• Nature of the impact (direct/indirect, positive/negative);
• Permanence of effect (temporary or permanent);
• Extent of influence and magnitude of the impact; and
• Inter-relationship between impacts.
3.20 The effects that will be considered to be significant prior to and following mitigation will be identified in the ES. The significance of residual impacts following mitigation reflects judgements as to the importance or sensitivity of the identified receptor(s) and the nature and magnitude of the predicted changes. For example, a large adverse impact on a feature or site of low importance will be of lesser significance than the same impact on a feature or site of high importance.
3.21 In order to provide a consistent approach in reporting the outcomes of the various studies undertaken as part of the preparation of the ES, the following terms will be used to describe impacts throughout the ES which were also used in the 2006 and 2007 ESs::
• Major Positive or Negative Impact - where the Development is likely to have a significant effect on the environment;
• Moderate Positive or Negative Impact - where the Development would cause a moderate effect;
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• Minor Positive or Negative Impact - where the Development would cause a minor effect; and
• Negligible – where there is no discernible effect on the environment.
3.22 Where significant environmental effects are identified, mitigation measures will be set out and the significance of the residual effect (with the mitigation measures implemented) will be stated within the ES. The significance of residual effects will also be determined in line with the assessment criteria established for each environmental topic and using the terminology provided above.
3.23 The duration of effects resulting from the Development is one of the factors to be considered in determining their significance. In order to distinguish between permanent and temporary, permanent effects are defined as those that result from irreversible change to the environmental baseline or which persist for the foreseeable future.
3.24 The significance of residual effects following mitigation will reflect judgements as to the importance or sensitivity of the affected receptors and the nature and magnitude of the predicted changes. Impacts that are considered significant prior to and following mitigation will be identified in the ES, as shown at Table 3.3 below.
Table 3.3 Classification of Duration of Impacts
Significance Definition Temporary The period over which the impact is experienced lasts for the period of construction or less
Permanent Impacts that are experienced without reduction or removal over time
Short-term Less than 5 years (but longer than the full period of construction)
Medium-term 5–10 years
Long-term The impact remains for a substantial time, for the duration of the operation of the Development
3.25 The following terms will be used to define the nature of impacts (note that specific definitions of the following terms will be provided in the detailed assessment methodologies for each ES chapter):
• Direct – effects as a result of the development construction or operation activities;
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• Indirect - Impacts on the environment, which are not a direct result of the project, often produced away from or as a result of a complex pathway. Sometimes referred to as second or third level impacts, or secondary impacts;
• Cumulative - Impacts that result from incremental changes caused by other past, present or reasonably foreseeable actions together with the project;
• Primary – Impacts that result upon a receptor as a direct environmental change or disturbance to a specific element; and
• Secondary – The result of primary impacts on the first receptor having a knock-on impact upon secondary receptors.
3.26 Where the above criteria are not used, the criteria that will be used will be stated within the methodology section of the technical chapters, giving reasons for their use.
3.27 The ES will also distinguish the geographical extent of impacts; the following definitions will be adopted (bold and capitalise each word) as per Table 3.4.
Table 3.4 Classification of Different Geographical Extents
Significance Definition Local The site and its immediate surroundings
County/Borough The wider area of Medway/ Kent
Regional The region (i.e. Southeast England)
National United Kingdom
International Europe and beyond
3.28 There have been no material changes to impact prediction and significance criteria for the updated ES as a result of the EIA Regulations 2017 compared to the 2007 ES. Where any material changes to impact prediction and significance criteria occur in individual ES Chapters, these are as a result of changes to specific best practice guidance for relevant technical areas. The updated technical guidance that has been used for the preparation of this ES will be out in the methodology section for each technical chapter.
Assumptions and Limitations
3.29 Certain assumptions will be made during the preparation of the ES, which are set out below. Assumptions and limitations specific to individual environmental aspects will be set out and discussed in the relevant chapters of the ES. It is assumed that:
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• Baseline conditions are accurate at the time of the physical surveys but due to the dynamic nature of the environment, conditions may change during the construction and operational phases;
• The assessment of any cumulative impacts has been based upon the information available at the time of writing (October 2020) and currently available assessment techniques; and
• The anticipated date of completion of construction of the Development would be in December 2024.
ES Structure
3.30 The proposed structure of the ES is set out below:
• Volume 1: Main Text and Figures;
• Volume 2: Technical Appendices; and
• Volume 3: Non-Technical Summary (NTS).
ES Volume 1: Main Text and Figures
3.31 The technical chapters will be collated into one document that will present the full text of the ES and will be illustrated throughout by a series of figures. The proposed chapters will be structured as listed below.
3.32 Each ES technical chapter will generally include:
• An introduction and brief summary of the topic under consideration in the chapter;
• The up to date policy and legislative context relevant to the topic;
• Details of the up to date impact assessment methodology employed and the scope of the assessment, with any limitations highlighted;
• Details of the relevant study area;
• The significance criteria employed to evaluate the magnitude of potential impacts;
• A description of the relevant up to date baseline conditions (Q3/4 2020) accompanied by details of the method employed to record those conditions;
• Impact prediction, both beneficial and adverse, during the construction and operational phases of the Development (based on proposed delivery of future phases). The data required to identify and assess the main effects which the development is likely to have. Any uncertainties will be described and, where assumptions have been used in the
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prediction of impacts, these will be highlighted and accompanied with an indication of the certainty that can be applied to those assumptions;
• A summary of the mitigation measures that are required to avoid, reduce or compensate for and if possible remedy, any significant adverse effects. These measures have been secured through the existing planning conditions; and
• A conclusion.
ES Volume 2: Technical Appendices
3.33 This will include the full text (or appropriate section) of any reports referenced within the ES technical chapters, such as the Technical Reports undertaken as part of the assessment and other relevant documents.
ES Volume 3: NTS
3.34 This document will provide a summary of the ES. The NTS will be presented using non- technical language to assist the reader to understand the site context, the Development, the environmental issues arising, and the mitigation measures to be implemented.
PROFESSIONAL TEAM
Competent Assessors
3.35 Table 3.5 sets outs a summary of the competent experts’ and their relevant experience, along with qualifications and experience of all the technical consultants who will contribute to the preparation of the ES. The ES will be written and co-ordinated by Greengage with contributions from the technical consultants described below.
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Table 3.5 ES Competent Experts’ Relevant Qualifications and Experience
Name and Technical Qualifications Relevant Experience Company Area Name
Mitch Cooke EIA BSc Over 20 years’ experience in the environment Coordination, sector. Leads a multidisciplinary team and is Greengage MSc Socio-Economic, expert in managing complex development Environmental Climate Change projects. EIA schemes include Grain Business & Risk Park, Grain LNG Phase 3, Brentford Community Stadium, Clapham Park, and Stratford Central.
James EIA BSc (Hons) Over 7 years’ experience managing EIA projects. Bumphrey Coordination Developments include Goldsworth Road, MSc Clapham Park, Pincents Lane, Thorpe Lea Road Greengage Egham and Cricklewood. Environmental
Andrew Landscape and BA (Hons) Over 18 years’ experience in landscape planning Tempany Visual and assessment and in providing landscape and Dip.LA visual impact assessment for EIAs for various RSK CMLI (Chartered developments, including nationally significant Environmental Member of the infrastructure projects and hybrid Bill schemes. Ltd Landscape Expert witness experience. EIA schemes include Institute). HS2 Phase 2a, North Stoneham Park and Meridian Water Phase 1 and Phase 2.
Chris Frain Landscape and BA (Hons) Over 21 years’ experience in landscape planning Visual and assessment and in providing landscape and RSK BLA visual impact assessment for EIAs for various Environmental CMLI (Chartered developments, including nationally significant Ltd Member of the infrastructure projects. DCO Expert witness Landscape experience. EIA schemes include Rail Central Institute). Strategic Rail Freight Interchange; Rampion offshore wind farm (onshore element) and Triton Knoll offshore wind farm (onshore element).
Duncan Stuart Transportation BSc (Hons) Over 5 years’ experience in the transport sector. Has worked on a diverse range of projects in all Vectos MSc aspects of transport planning including ES Transport Chapters. EIA schemes include Oval Gasworks and Tesco Kennington.
Daniel Clare Noise and BSc (Hons) Over 16 years’ experience in the acoustics Vibration industry. Leads the RSK Acoustics team and has RSK MIOA managed the acoustic element on a number of Environmental MIEnvSc DCO, EIA and internationally IFC funded projects Ltd throughout the UK, Africa, Middle East and Europe.
Relevant project experience includes Centrica Storage at its Easington Terminal, various Northern Gas Network sites, various Alkane Energy sites and the onshore electrical
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infrastructure components associated with the Rampion Offshore Wind Farm.
Graeme Noise and BSc (Hons) Over 11 years’ experience in the environment Parker Vibration sector. Has extensive experience of assessing MIOA noise for energy developments including coal RSK power, biomass, recycling, agricultural and Environmental renewable energy installations including wind Ltd farms, solar farms, anaerobic digestion units and energy from waste installations.
Dr Srinivas Air Quality BEng Over 28 years’ experience in the environment Srimath sector. Leads the air quality and permitting team MEng and is a technical expert in managing air quality RSK PhD matters related to large infrastructure projects. Environment EIA schemes include large mixed-use/residential Ltd developments in Sittingbourne and Dartford. Provided air quality support to energy sector clients including Shell, Centrica, BP, National Grid and TOTAL in respect of planning and environmental permitting matters.
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4.0 SCOPE OF TECHNICAL ASSESSMENTS
4.1 The following section sets out the scope of assessment for each technical Chapter of the ES.
LANDSCAPE AND VISUAL IMPACT ASSESSMENT
Known Baseline
4.2 The site is located on the Isle of Grain which is separated from the wider Hoo Peninsula by Yantlet Creek. The southern half of the Isle of Grain is defined as Urban and Industrial Areas in the Medway Landscape Character Assessment10, and the northern half is defined as being part of the Medway Marshes landscape character area. The settlement of Grain village is located on the eastern side of the Isle of Grain and forms part of the Urban and Industrial character area, there is a swathe of arable agricultural land that separates the village from the Combined Cycle Gas Plant, Grain LNG and brownfield sites associated with former industrial uses.
4.3 Yantlet Creek and its expansive low-lying floodplain consist of mudflats and marshes that forms part of the Medway Estuary and Marshes; this extends around the peninsula and it designated as a Ramsar Site, Site of Special Scientific Interest (SSSI) and Special Protection Area (SPA) due to the outstanding and internationally important bird habitat it provides. Qualifying features of the designated habitat have a notable expression on landscape character, these include a mosaic of wetland and scrub habitats, saltmarsh, grazing marsh, mudflats, pasture, and an intricate pattern of creeks and dykes.
4.4 The local landscape is characterised essentially by the flat topography and expansive skylines. The exposed open character of the landscape is dominated in the southeast by the massing and scale of the existing industrial facilities and infrastructure. The most prominent existing feature is the Combined Cycle Gas Plant and its associated chimneys, electricity transmission lines and pylons. These transmission lines and pylons cross the flat landscape and serve to visually define the edge of the industrialised area. Other major industrial developments on the Isle of Grain are the large Phase 3A tank on-site, the other large tanks of the existing Grain LNG Importation Facility adjacent to the site and the large cranes of Thamesport. Many features within these complexes protrude well above the skyline and, as a consequence, are dominant relative to many other features in the landscape, such as trees and residential developments.
4.5 The Development is remote from settlements and residential development. However within 2km of the site, farmsteads at Perrys Farm and Rosecourt Farm are located to the northeast, along with a very small residential development adjacent to the B2001 on the outskirts of
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Grain village including the properties known as Yantlet Range to the east of the site. The nearest properties to the site are those positioned along the B2001 at a distance of approximately 1km to the east. The outskirts of Grain village lie approximately 1.3km to the east of the site. Other, smaller settlements include Allhallows-on-Sea and Allhallows, located approximately 3.3km to the north-west; Lower Stoke, located approximately 3.6km to the west; the very small settlement of Middle Stoke, located approximately 3.8km to the south- west; and Stoke, located approximately 4.6km to the south-west. The Development is also remote from the larger centres of population, such as Queensborough and Sheerness, on the southern banks of the River Medway, with Queensborough being approximately 6km distant, and across the Thames, Southend being some 9km distant.
4.6 Ground preparation and fencing works have previously been partially completed as a part of the Phase 3A works. The construction laydown area is located on the semi-derelict, brownfield land of the former BP Kent Oil Refinery Complex. This area is flat, open and almost featureless, it appears to be unmanaged and has consequently been colonised by grasses and ruderal vegetation, with occasional areas of scrub vegetation. The resultant landscape character of the Grain site is somewhat degraded, although the surrounding network of ditches and waterbodies provides habitat for water vole.
4.7 The Grain LNG site is dominated by a series of storage tanks, the larger of which are the four 50m high tanks constructed in Phases 2 and 3A; together with the five smaller tanks to the south, the site is prominent in views within the low-lying surrounding landscape. The cluster of existing tanks are particularly prominent in views from the west, where roads and PRoWS are at a similar elevation to the tanks, and from the villages in the northwest where the topography is slightly higher and the site remains highly visible, however the higher topography also increases views of the industry that is inextricably linked to the estuarine corridor; resulting in far more visual detractors. The prominence of the existing tanks within the landscape is a result of their scale, form and colour. The metallic construction and the off white colouring contribute to the prominence of these tanks due to the reflective properties, particularly in bright, sunny conditions.
4.8 As part of a previous planning consent for the Grain LNG site, linear belts of trees and shrubs were planted in the late 1980’s providing a vegetated buffer between the site and the B2001 Grain Road. These are now well established and generally screen views towards the site, there are some breaks associated with access points and the site becomes more visible where the planting ends on the eastern boundary. The site will also be more visible during the winter when trees are out of leaf, however this would be limited to filtered views.
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4.9 There are a number of consented and emerging schemes in the surrounding area that will affect the existing landscape. The impact of the Development within this cumulative context will also be considered by the Landscape and Visual Impact Assessment (LVIA) ES Chapter.
Potential Effects
4.10 As the Phase 3A development has been operational since 2010 there are no further Landscape and Visual effects that will be associated with the Phase 3A development and it is proposed to scope this out of the Landscape and Visual Assessment. Mitigation has already been incorporated for Phase 3A in accordance with the 2007 ES and secured through Condition 2 and 3 of the Second Permission.
4.11 The Phase 3A development will therefore be considered as part of the baseline based on updated visualisations.
4.12 Phase 3B will include one LNG storage tank with an approximate height of 50.1m and slab diameter of 94.8m, plus ancillary structures and pipework associated with 2No submerged combustion vaporisers. The Phase 3B LNG tank will sit adjacent to the Phase 3A tank and will be of the same scale, form and colour; it does not therefore materially change the arrangement and appearance of the existing permission.
4.13 The Phase 3B development is likely to give rise to a significant impact by virtue of the effect on the surrounding landscape character and visual impacts on nearby receptors. The Phase 3B development will be seen in the context of the existing earlier development and the Phase 2 and Phase 3A LNG tanks on the Grain LNG site.
4.14 There are a number of consented and emerging schemes in the surrounding area that will alter the existing landscape.
Assessment Methodology
4.15 The methodology for the assessment will be based on nationally accepted, industry wide good practice guidance contained within the Guidelines for Landscape and Visual Impact Assessment, 3rd Edition (or ‘GLVIA3’)11. Account will also be taken of other relevant good practice guidance, notably updated approaches to landscape characterisation12 and landscape sensitivity analysis13 from Natural England, plus industry guidance on the production of visual representations14.
4.16 Given the changes in methodology and guidance since GLVIA2 which the previous Landscape and Visual ES Chapters were based on, some aspects of the methodology (particularly around value and susceptibility to inform sensitivity) have changed considerably since the previous Landscape and Visual ES Chapters produced for the 2006 and 2007 ESs.
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4.17 This assessment consider will consider the following, within a 6km study area (which is consistent with the 2006 and 2007 ESs and is appropriate to capture the range of likely significant landscape and visual effects arising from the construction and operation of the Phase 3B development):
• Landscape character baseline from national to local, including discussion of landscape value and sensitivity (including susceptibility to change arising from the Phase 3B development).
• Visual baseline, in terms of agreed specific, representative and illustrative viewpoints including discussion of view value and receptor sensitivity including susceptibility to visual change arising from the Phase 3B development). Due to the project programme, consultation has not been undertaken with the Local Planning Authority with regard to the viewpoints, however the viewpoints are the same as those agreed as part of the scoping process for the 2006 ES which essentially addressed the elements of the scheme now being brought forward for Phase 3B.
• The magnitude of change to landscape receptors and visual receptors respectively arising from the construction and operation of the Phase 3B development.
• The level or significance of effect upon landscape receptors and visual receptors respectively, resulting from the construction and operation of the Phase 3B development, and with consideration to receptor sensitivity and magnitude of change.
• Appropriate proposed landscape and visual mitigation, plus an assessment of residual or remaining effects after implementation of mitigation, as appropriate.
• An assessment of cumulative landscape and visual effects, considering the Phase 3B development in the context of other comparable consented and/or proposed schemes.
4.18 The assessment will be supported by appropriate visualisations, to Landscape Institute Type 3 format, to give an indication of likely visual appearance and effect, and to inform the impact assessment.
Mitigation
4.19 Construction mitigation will be determined based on existing planning conditions and the preparation of a CEMP in accordance with best practice.
4.20 During operation, mitigation measures will be embedded into the design in terms of materials and finishes.
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4.21 Due to the operational requirements of the scheme and the need to maintain fire safety buffers to the LNG tank and avoidance of flammable material, boundary planting, whilst helpful in masking ground level components of the scheme, is not considered practicable.
TRANSPORTATION
Known Baseline
4.22 The impact that any particular change in traffic conditions has on the environment is dependent on a wide range of factors, including volume, speed, composition and operational characteristics.
4.23 Similarly, the perception of change in highway conditions varies according to factors such as existing traffic levels, road layout, time of day and land-use activities adjacent to the route under assessment.
4.24 In this context, any assessment of traffic related environmental impacts requires an assessment of future conditions relative to an established baseline position.
4.25 The location of the site and the layout of the road network is such that only one traffic route exists to provide access to the site from the strategic road network (to the west of the Development).
4.26 Road access relies upon the A228/B2001 Grain Road. At the A228/A289 junction, referred to locally as the Four Elms roundabout, there is a choice of strategic routes with the A289 (west) providing access to/from London via the A2 and the A289 (east) providing access to the Medway Towns via the Gillingham Northern Link Road.
4.27 The A228 from Four Elms roundabout to Ropers Lane is a dual two-lane carriageway with a speed limit varying between 40mph and 70mph.
4.28 From Ropers Lane to Christmas Lane, the A228 is a wide single carriageway road. This section of the A228 route provides a bypass to Sharnal Street. A speed limit of 60mph applies.
4.29 From Christmas Lane roundabout, the A228 route continues east towards Hoo Peninsula and the site. Along this section of the route, the horizontal alignment of the single carriageway road varies considerably. The A228 from Christmas Lane to the site is subject to a 40mph speed limit and is enforced by a SPECS average speed camera system. Overtaking restrictions also operate between Christmas Lane and the site.
4.30 The A228 north of Christmas Lane connects with Fenn Street by way of a roundabout junction.
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4.31 East of Lower Stoke the A228 route alignment is less varied. Immediately east of Stoke village, an approximate 2.5km length of the A228 passes through the North Kent Marshes Special Landscape Area. The A228 then passes over a railway by way of a bridge, which previously operated as a level crossing.
4.32 In the vicinity of the access points to the Thamesport and the wider Grain site, the alignment of the road turns sharply towards the north east and the route is reclassified as the B2001.
4.33 There are limited bus services that currently serve the development site or sites adjacent to the development area. There are a number of existing bus services i.e. 191, 196 and 796 that serve the Grain village; however, the development site does not form an official stop on any of these routes.
4.34 There are currently no passenger rail services that directly serve the site. The nearest railway stations are located in Higham and Strood and provide a number of services to both local destinations, i.e. the Medway Towns and further afield to London. The location of both of these stations and frequency of services provide an opportunity to commute to the site, albeit as part of a multi-modal journey.
4.35 A number of local settlements i.e. Grain, Stoke and Allhallows have the potential to be accessed either on foot or by bike, although it is considered due to the site’s location and use, these modes will not form a significant proportion of trips being made to the site.
4.36 Highway safety improvement measures have been implemented by Kent County Council, including average speed cameras and road markings which should also help improve the overall environment.
4.37 Observed traffic flows have been obtained from Automatic Traffic Counts (ATCs) undertaken on a number of highway links within the study area during the period of 3rd to 9th November 2014 at the following locations:
• ATC A – A289 Wainscott Bypass, approximately 200m northwest of Four Elms roundabout (dual-carriageway);
• ATC B - A289 Wainscott Bypass, approximately 200m southeast of Four Elms roundabout (dual-carriageway);
• ATC C - A228 Four Elms Hill approximately 200m east of Four Elms roundabout (dual-carriageway);
• ATC D - A228 between Chattenden Lane and Main Road junctions (dual- carriageway);
• ATC E - A228 between Main Road and Bells Lane junctions (dual-carriageway);
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• ATC F - A228 between Roper’s Lane and Christmas Lane junctions;
• ATC G - Christmas Lane, approximately 200m west of the junction with the A228;
• ATC H - A228 between Fenn Corner and Lower Stoke junctions;
• ATC J - A228 between Lower Stoke and Thamesport site access junctions; and
• ATC K - B2001 approximately 50m northeast of Thamesport access.
4.38 Due to COVID-19 creating the potential for irregular traffic flows the 2014 flows are deemed more representative of the highway network. The results of the ATC surveys are tabulated in table 6.2, providing a detailed summary of the two-way flows at each ATC location.
Table 6.2 Summary of ATC Traffic Two-way Flow Data (Total Vehicles)
Time ATC ATC ATC ATC ATC ATC ATC ATC ATC ATC Period A B C D E F G H J K Annual Average 39,75 42,71 31,39 29,85 20,81 12,26 Weekday 1,849 6,775 5,383 3,903 8 0 6 5 4 3 Traffic (AAWT)
Annual Average 36,18 39,17 29,16 27,59 19,04 11,13 Daily 1,762 5,900 4,548 3,430 3 0 9 3 9 0 Traffic (AADT)
18-hour 37,35 40,76 30,14 28,65 19,86 11,70 Weekday 1,812 6,357 5,050 3,748 1 9 5 9 0 2 Flow
07:00 08:00 07:00 07:00 07:00 07:00 08:00 07:00 07:00 07:00 AM Peak ------Hour 08:00 09:00 08:00 08:00 08:00 08:00 09:00 08:00 08:00 08:00
AM Peak 3,308 3,525 2,466 2,267 1,794 1,025 155 683 568 408 Hour Flow
AM traffic as a % of 8.3% 8.3% 7.9% 7.6% 8.6% 8.4% 8.4% 10.1% 10.6% 10.5% 24-hour traffic
AM Proportio 6.7% 5.4% 5.6% 4.8% 5.2% 6.6% 2.9% 7.9% 10.4% 4.6% n of HGVs (%)
16:00 16:00 17:00 17:00 17:00 16:00 16:00 16:00 16:00 16:00 PM Peak ------Hour 17:00 17:00 18:00 18:00 18:00 17:00 17:00 17:00 17:00 17:00
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PM Peak Hour Flow 3,033 3,219 2,517 2,450 1,681 1,058 155 605 456 350 (17:00- 18:00)
PM traffic as a % of 7.6% 7.5% 8.0% 8.2% 8.1% 8.6% 8.4% 8.9% 8.5% 9.0% 24-hour traffic
PM Proportio 6.9% 5.6% 3.3% 3.8% 3.0% 2.9% 2.5% 3.6% 5.0% 2.5% n of HGVs (%)
18 hour flow 37,35 40,76 30,14 28,65 19,86 11,70 1,812 6,357 5,050 3,748 (0600 – 1 9 5 9 0 2 0000)
18 hour traffic as a % of 94.0% 95.5% 96.0% 96.0% 95.4% 95.4% 98.0% 93.8% 93.8% 96.0% 24-hour traffic
18 hour HGV 7.0% 5.2% 4.9% 4.7% 3.9% 6.1% 2.8% 8.2% 10.2% 4.1% proportio ns (%)
24 hour 39,75 42,71 31,39 29,85 20,81 12,26 1,849 6,775 5,383 3,903 flow 8 0 6 5 4 3
24 hour HGV 6.9% 5.3% 5.0% 4.8% 5.5% 6.5% 2.8% 9.4% 10.4% 4.0% proportio n (%)
Potential Impacts
4.39 Given that the Phase 3A development has been operational since 2010, the operational traffic is considered as part of the baseline flows provided above. As part of the Phase 3A development, a Construction Travel and Transport Plan was also implemented in accordance with Condition 22 of the Second Permission. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Transportation.
4.40 The Phase 3B development has the potential to result in significant transportation impacts during construction due to the volume of traffic associated with the Phase 3B development during peak construction periods.
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4.41 Potentially significant impacts therefore include the impacts of construction traffic from Phase 3B on:
• Changes in traffic flows;
• Severance;
• Driver Delay;
• Pedestrian Delay;
• Pedestrian and Cyclist Amenity;
• Fear and Intimidation;
• Accidents and Safety; and
• Hazardous Loads.
4.42 No significant operational transportation effects were identified in the 2007 ES.
4.43 The operation of the Phase 3B development is expected to require 12 permanent staff and consequently will not require assessment for additional vehicle movements. The operation of the Phase 3B development will not be associated with any HGV movements. Therefore no likely significant transportation impacts are predicted during the operation of Phase 3B although this will be confirmed in the updated ES.
4.44 The assessment will also consider the traffic flows generated by the construction and continuing operation of the committed cumulative developments.
Mitigation
4.45 Mitigation measures for Phase 3B will include the preparation and implementation of a Construction Transport and Travel Plan (in accordance with Condition 16 and Condition 22) incorporating details the following:
• Wheel washing;
• Access arrangements;
• Provisions for deliveries; and
• Pedestrian segregation.
4.46 A CEMP will also be prepared and implemented by the contractor in accordance with best practice.
4.47 Given the low number of additional permanent operational staff for Phase 3B, it is considered unlikely that any operational transport mitigation will be required.
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Assessment Methodology
4.48 The assessment will be undertaken in accordance with the Institute of Environmental Management and Assessment (IEMA) publication ‘Guidelines for Environmental Impact Assessment’ (2004). Those criteria will be based on the net change in journeys as a result of the Phase 3B development. The significance criteria will establish the magnitude of any beneficial or adverse traffic and transport effects of the Phase 3B development.
The key areas which will be assessed for construction operational traffic from Phase 3B are as follows:
• Changes in traffic flows;
• Severance;
• Driver Delay;
• Pedestrian Delay;
• Pedestrian and Cyclist Amenity;
• Fear and Intimidation;
• Accidents and Safety; and
• Hazardous Loads.
4.49 The method of assessing the impacts of the construction and operational phases of the Phase 3B development on traffic and transport involves:
• Describing the existing transport network, existing road traffic flows and the receptors that are potentially sensitive to traffic and transport impacts;
• Identifying the future baseline conditions based on factored survey information and the expectations of public transport;
• Predicting the traffic impacts that are likely to arise during the construction and operation of the Development; and
• Identify measures to mitigate any predicted impacts.
4.50 Within the IEMA Guidelines, two broad rules are suggested to be used as a screening process to limit the scope of assessment:
• ‘Rule 1: include highway links where traffic flows or HGVs would increase by more than 30%; and
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• Rule 2: include any other specifically sensitive areas where traffic flows have increased by 10% or more.’
4.51 The above criteria will be used to identify links to be assessed as part of the Transportation ES Chapter. Where assessment confirms that increase in HGV or traffic flows fall below the 30% / 10% threshold on any link then the environmental assessment of that link in the context of this assessment is not required.
4.52 The impact of development (both construction and operational) traffic on the highway network is represented by determining the impact of the two-way development traffic as a percentage of the two-way baseline year traffic on the links within the study area.
4.53 It should be recognised that the percentage impact on an existing highway does not always accurately assess the appropriateness of a development, such as in situations where roads have been constructed prior to implementation of a development and therefore, have no or very low volume of traffic flow on them.
4.54 In the absence of criteria designed to specifically assess the impacts from the construction phase on existing traffic conditions, a common-sense approach and professional judgement will be used to identify any impacts that may occur in the event of exceeding the criteria. Therefore, although the criteria described above are designed to assess long-term traffic impacts, this will also be used to assess the impacts associated with construction of the Phase 3B development.
4.55 These criteria are not prescriptive, and consideration needs to be given to local conditions, existing flows and the temporary nature of any potential impacts in determining the likely magnitude of traffic impacts.
4.56 The impacts of the development traffic are defined in terms of ‘levels of significance’. They are described as either positive or negative and are reproduced in the table below. These definitions and their associated level of change are based on guidance found within the Guidelines on the Environmental Assessment of Road Traffic as shown in Table 6.1.
Table 4.1 Impact Definitions
Degree of Impact Definition
Development traffic would create a major Major Negative increase in traffic movements above 90% during the peak hours
Development traffic would create a moderate Moderate Negative increase in traffic movements above 60% during the peak hours
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Degree of Impact Definition
Development traffic would create a minor Minor Negative increase in traffic movements above 30% during the peak hours
Development traffic is likely to create only Negligible marginal changes in traffic movements.
Development traffic would create a minor Minor Positive decrease in traffic movements above 30% during the peak hours
Development traffic would create a moderate Moderate Positive decrease in traffic movements above 60% during the peak hours
Development traffic would create a major Major Positive decrease in traffic movements above 90% during the peak hours
4.57 A worst-case estimate of traffic generation will be presented, which assumes that the majority of employees and construction traffic arrive by road. There is, however, the opportunity for a number of employees to arrive by public transport and other modes including car sharing and as such, there is potential for the volume of construction vehicles to reduce. There is also potential for a number of construction HGV trips that would otherwise be undertaken by road to be undertaken via rail, again further reducing the volume of construction traffic on the adjacent highway.
4.58 With the presentation of a worst-case traffic generation profile, any uncertainty surrounding the derivation of trip generation associated with the Phase 3B development has been minimised.
NOISE AND VIBRATION
Known Baseline
4.59 A field assessment of the local area has identified the following residential receptors in the vicinity of the site boundary (both to the northeast of the site):
• ‘Perry’s Farm Cottages’ (2x residential properties) (approx. E587910, N176492)
o Approximately 800 m from the site
• ‘Westbere’ (residential property) (approx. E588235, N176281)
o Approximately 1000 m from the site
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Figure 4.1 Noise Sensitive Receptors
4.60 Given the relative distance between the site and sensitive receptors (the nearest residential properties are more than 800 m from the site), baseline vibration monitoring was not considered necessary.
4.61 A background noise survey has been undertaken to define the noise levels in absence of the Phase 3B development at the Grain LNG importation facility. The resultant measurement data has been used to inform the assessment. The survey comprised unattended measurements at two locations at representative locations of the closest noise sensitive receptors (UT1 and UT2).
4.62 UT2 has been used as a proxy location to quantify the existing noise environment for the considered noise sensitive receptors at Perry’s Farm Cottages as it was not possible to monitor adjacent to the considered receptor.
4.63 The noise environment at the unattended measurement locations were both dominated by traffic movements on the surrounding road links. Other less prominent sources of noise were noted to be attributable to bird calls / song and wind-blown foliage. Additionally, the LNG site was noted to be not audible during installation or retrieval of equipment at UT1 or UT2.
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4.64 A series of short duration attended noise measurements were carried out on 20th October 2020 externally along the north eastern boundary of the existing site, between the existing site and the nearest noise sensitive receptors.
4.65 An unattended baseline noise level survey was undertaken between 15th October 2020 and 19th October 2020. An unattended sound level meter was positioned on the north eastern boundary of the site to quantity typical noise levels emanating from the existing site.
4.66 Furthermore, attended short term noise monitoring was conducted at a proxy location as close as practicable to the nearest noise sensitive receptors.
Potential Impacts
4.67 Given that Phase 3A has been operational since 2010, the baseline noise surveys have included any noise from existing Phase 3A plant along with other existing plant noise as part of the wider Grain LNG importation facility. In addition, as part of the Phase 3A development, construction works and the subsequent operation of Phase 3A were undertaken in accordance with Condition 15 and Condition 17-20. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Noise and Vibration.
4.68 The Noise and Vibration assessment will include a Construction Phase Noise Assessment and an Operational Phase Plant Noise Assessment for Phase 3B based on the impact of these on nearby sensitive receptors. The Noise and Vibration Assessment will also consider the impact of traffic noise during the construction and operation of Phase 3B.
4.69 Vibration effects from Phase 3B construction activity have been scoped out of the assessment due to the relative distance between source and receivers (the nearest residential properties are more than 800 m from the site), and unlikelihood of any significant vibratory methods of construction being used on the site.
4.70 While construction vibration was previously considered in the 2007 ES, vibrational impacts in the 2007 ES only considered the nearest residential receptors to the site at Harvest Cottages which are no longer occupied.
Mitigation
4.71 Planning conditions 17 and 20 of the Second Permission have already been discharged. However, based on the mitigation identified as part of the updated construction noise assessment noise control measures will be incorporated into an updated ‘Control of Construction Noise’ report for Phase 3B. These measures will reflect those set out in BS 5228:2009.
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4.72 A CEMP will also be prepared and implemented by the contractor in accordance with best practice.
4.73 Mitigation measures during the operational phase will be identified, if required, based on the results of the operational noise assessment.
Assessment Methodology
4.74 Guidance regarding the assessment of the magnitude of noise impacts is available within IEMA’s ‘Guidelines for Environmental Noise Impact Assessment’. This document sets out key principles and advice on how to effectively integrate noise impacts and effects into the consenting process of all types of development. The document provides advice on how to categorise the significance of the noise impact based on noise change. The document indicates that generally there is no precise guidance for determining the overall significance of the noise impact. The magnitude of noise impact should be stated as the predicted noise level and not simply as an impact category.
4.75 At this stage, a building contractor is not currently involved with the project. However, an initial estimate of the expected noise levels over a representative period will be provided using the currently available information. The effects of noise during the construction phase will be assessed qualitatively in accordance with the British Standard 5228-1:2009+A1:2014 ‘Code of Practice for Noise and Vibration Control on Construction and Open sites – Part 1: Noise’15. This enables predictions to be made of the noise emissions from the construction activities for given distances from the works. The assessment assumes that all plant would operate at a given location within the site, which is a highly precautionary assessment as plant would typically be distributed over a wider work area.
4.76 An operational phase plant noise assessment will also be undertaken.
4.77 BS 4142: 2014+A1:2019 describes the methods for rating and assessing noise from industrial or commercial sources, including manufacturing processes, fixed installations and plant equipment, loading of goods and sound from mobile plant. The standard is applicable for the purpose of assessing sound at proposed new dwellings, through the determination of a rating level of an industrial or commercial noise source.
4.78 Where certain acoustic features are present at the assessment location, a character correction should be applied to the specific sound level to give the rating level to be used in the assessment.
4.79 BS 8233 provides good internal design threshold for new developments, including residential. This standard is derived from the WHO Guidelines for Community Noise. For
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the use of BS 4142 in assessing new residential development applications, ProPG (Paragraph 2.43) states that:
‘Professional judgement will have to be exercised in addressing these sorts of issues. One possible approach may be to apply BS 4142:2014 character corrections to the noise level guideline values in order to derive suitable effect thresholds and/ or mitigation design targets and to use the same reference time periods recommended in the standard’.
4.80 Where the initial estimate of the impact needs to be modified due to the context, all pertinent factors should be taken into account, including:
• The absolute level;
• The character and level of the residual sound;
• The sensitivity of the receptor and whether dwellings will already (or likely) to incorporate design measures that secure good internal and/or outdoor acoustic conditions, such as: i) façade insulation treatments, ii) ventilation and/or cooling, and iii) acoustic screening.
4.81 It is therefore not considered appropriate to use the BS 4142 impact assessment method as a means of solely determining suitability for the development site. Based on the guidance provided in BS 4142, the context and incorporated design measures should be the primary features of determining suitability and therefore, BS 8233 and WHO are considered to be the principle standards for derivation of design targets and subsequent assessment. However, the contextual nature of the noise sources and the penalty corrections for nearby commercial activity (for tonality, impulsive or intermittent noise sources) should be considered and applied to the noise source predictions/measurements or to the BS 8233/WHO design target.
4.82 The noise levels generated by the Phase 3B LNG storage tank and ancillary equipment will be calculated using a noise prediction model. This will been calculated in isolation from the rest of the existing site to provide a contribution at the boundary and nearest receptors. The contribution will then be compared with existing LNG values to determine impact.
4.83 The noise predictions (specific sound levels at noise sensitive receptors) are based on International Standard ISO 9613-2:1996 ‘Attenuation of sound during propagation outdoors – general method of calculation’. ISO 9613 provides a method for the prediction of noise levels in the community from sources of known sound emission.
4.84 The ISO 9613-2 method predicts noise levels under meteorological conditions favourable to noise propagation from the sound source to the receiver, such as downwind propagation, or equivalently, propagation under a moderate ground-based temperature inversion as commonly occurs at night.
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4.85 A computer noise model of the site has been produced using SoundPLAN v8.2 based on the most up to date site layout with consideration of the positioning/orientation of all buildings and external structures.
4.86 Input data in the form of noise emission levels will be assigned to the Phase 3B plant, adjusted to the geometry and nature of the site operations for the site.
4.87 The noise prediction method described in ISO 9613 is suitable for a wide range of engineering applications where the noise level outdoors is of interest. The noise source(s) may be moving or stationary and the method considers the following major mechanisms of noise attenuation:
• Geometrical divergence (also known as distance loss or geometric damping);
• Atmospheric absorption;
• Ground effect;
• Reflection from surfaces; and
• Screening by obstacles, barriers and buildings.
AIR QUALITY
Known Baseline
4.88 Existing or baseline air quality refers to the concentrations of relevant substances that are already present in ambient air. These substances are emitted by various sources, including road traffic, industrial, domestic, agricultural and natural sources.
4.89 There are currently four Air Quality Management Areas (AQMAs) declared within Medway,
due to exceedances of the annual mean nitrogen dioxide (NO2) objective. The nearest AQMA is the Four Elms Hill AQMA, which is located approximately 11.5km away. Therefore, the site is not located within an AQMA.
4.90 The main pollution sources in the vicinity of the site are the existing Grain LNG importation facility including the existing Phase 3A tank and vehicles travelling on the local road network.
Potential Impacts
4.91 The construction of Phase 3A was completed in 2010 and construction works of Phase 3A were undertaken in accordance with Condition 16 and 17 of the Second Permission.
4.92 Given that Phase 3A has been operational since 2010, the operational phase impacts of the Phase 3A development are now considered as part of all baseline air quality data and
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mitigation has already been incorporated into the operation of Phase 3A in accordance with that set out in the 2007 ES including:
• SCVs with low NOx technology;
• A regular maintenance programme for fixed equipment has been implemented to ensure that their operation is efficient and within the design specification; and
• Emissions have been and continue to be monitored for compliance with the limits set by the Environment Agency under the IPPC licence.
4.93 Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Air Quality.
4.94 The potential impacts as a result of the Phase 3B development have been determined as:
• Potential temporary increase in dust generated by on-site activities during the construction phase of the Phase 3B development;
• Potential increase in particulate matter (PM10) concentrations generated by on-site activities during the site earthworks and construction phase of the Phase 3B development;
• Potential increase in air pollutants (NO2 and particulate matter PM10) generated from construction plant and vehicle exhaust emissions during the site preparation, earthworks and construction phase of the Phase 3B development; and
• Potential change in pollutant concentrations (notably NOx NO2 and CO) due to exhaust emissions generated during the operational phase of the Phase 3B development.
4.95 The assessment will consider sensitive human receptors as well as the impact of NOx concentrations at sensitive ecological receptors within any special areas of conservation (SACs), special protection areas (SPAs) and Ramsar sites within 10km of the site, and at any sites of special scientific interest (SSSIs) within 2km of the site.
4.96 The assessment will therefore consider 8 representative ecological receptors at the following designated sites:
• South Thames Estuary and Marshes SSSI;
• Thames Estuary and Marshes Ramsar/SPA;
• Medway Estuary and Marshes SSSI/Ramsar/SPA;
• Benfleet and Southend Marshes SSSI/Ramsar/SPA; and
• Foulness SSSI/SPA/Ramsar & Essex Estuaries SAC.
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Mitigation
4.97 Condition 16 and 17 of the Second Permission have already been discharged through the approval of the ‘Air Quality and Dust Measures’ report for Phase 3A.
4.98 Mitigation measures during the construction phase will be recommended in-line with the Institute of Air Quality Management (IAQM) guidance16, and be incorporated into an updated ‘Air Quality and Dust Measures’ report as well as the CEMP for the Phase 3B development.
4.99 Mitigation measures during the operational phase will be identified, if required, based on the results of the modelling assessment.
Assessment Methodology
4.100 The assessment will be based on the following best practice guidance:
• Institute of Air Quality Management (IAQM), Guidance on the Assessment of Dust from Demolition and Construction, 2016;16
• Environmental Protection UK (EPUK) and IAQM, Land-Use Planning and Development Control: Planning for Air Quality, 2017;17
• Department for Environment, food and Rural Affairs, Technical Guidance LAQM.TG (16), 2018;18 and
• Department for Environment, food and Rural Affairs, Air emissions Risk Assessment for Your Environmental Permit, 201619.
4.101 An assessment of the likely significant effects of construction phase dust and particulate matter at sensitive receptors will be undertaken following the IAQM’s construction dust guidance, the available information for this phase of the Phase 3B development provided by the project team and professional judgement.
4.102 Exhaust emissions from construction vehicles and plant may have an effect on local air quality adjacent to the routes used by these vehicles to access the site and in the vicinity of the site itself. As information on the number of vehicles and plant associated with each part of the construction phase was not available at the time of assessment, a qualitative assessment of their effect on local air quality will be undertaken using professional judgement and by considering the following:
• The number and type of construction traffic and plant likely to be generated by this phase of the Phase 3B development;
• The number and proximity of sensitive receptors to the site and along the likely routes to be used by construction vehicles; and
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• The likely duration of the construction phase and the nature of the construction activities undertaken.
4.103 Once operational, the Phase 3B development will generate additional exhaust emissions in the local area, which will have the potential to impact on nearby sensitive receptors. In order to predict the effect of exhaust emissions arising from the Phase 3B development, the dispersion model BREEZE AERMOD (Version 9.0.0.23) will be used. This model uses detailed information regarding the pollutant releases, local building effects and local meteorological conditions, to predict pollutant concentrations at specific locations selected by the user and is approved by the Environment Agency (EA) for regulatory applications.
SOCIO-ECONOMIC
Known Baseline
4.104 The site is located within the unitary authority of Medway in the County of Kent. According to data from the Office for National Statistics, the site is located with the Medway Travel to Work Area (TTWA)20. This area encompasses the unitary authority of Medway and surrounding areas including Maidstone and the Isle of Sheppey.
4.105 According to the 2011 census, Medway has a total population of 263,925 persons, of which 49.6% are males and 50.4% are females21.
4.106 The employment and unemployment figures for the 2011 census show that in Medway, 71.1% of residents are economically active, compared to 72.1% in the South East and 69.9% in England22.
4.107 In Medway, according to the 2011 census, 19.1% of residents hold Level 4 qualifications and above, the highest level in this category encompassing different types of university degrees23. The proportion of residents with Level 4 qualifications or above in Medway is lower than the regional and national averages of 29.9% in the South East and 27.4% in England. The proportion of residents in Medway with no qualifications (22.9%) is also slightly higher than in the South East (19.1%) and but similar to England (22.5%).
Potential Impacts
4.108 As part of the Phase 3A development, mitigation set out in the 2007 ES was implemented around restrictions on construction worker accommodation. In addition, as the Phase 3A development has been operational for the last 10 years no new operational employment are now likely to come forward as a result of Phase 3A. Therefore, no updates to the
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environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Socio-economic impacts.
4.109 For the Phase 3B development, potential impacts are considered to include the following:
• The quantum of construction work and its anticipated employment generation;
• The quantum of operational employment opportunities generated on-site;
• Associated impacts on social infrastructure (including housing provision and education services) due to incoming employees during construction and operation; and
• Indirect socio-economic impacts due to increasing the capacity of the Grain LNG importation facility.
4.110 The 2006 ES and 2007 ES considered the impacts of the Development and wider Phase 3 proposals under the First Permission on recreation. However, the only significant effects were identified as a result of the construction and operation of the Jetty which has now been built and is no longer a part of the Development considered under the Second Permission. Therefore, considering the distance to recreational receptors and the updated baseline, further consideration of the recreational impacts of the Phase 3B development is proposed to be scoped out of this updated ES.
Mitigation
4.111 Mitigation set out in the 2007 ES around restrictions on construction worker accommodation will also be implemented for Phase 3B. The Socio-economic assessment will update the baseline and policy context to identify if any new mitigation is required to mitigate against any significant negative impacts.
Assessment Methodology
4.112 The likely socio-economic effects generated from the Phase 3B development will be examined and accompanied by an assessment of their relative significance. In particular, the assessment will address the direct and indirect employment opportunities generated during the construction and operational phases, and potential impacts upon the social infrastructure of the area. The findings of the assessment will be presented in a Socio- economic ES Chapter.
4.113 The baseline conditions for the site will first be established through undertaking a policy review and a desktop review. The desk top review will provide information on current socio- economic conditions using relevant local, sub-regional, regional and national data, including employment demographics. The primary data sources will be the 2011 Census and 2019-
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2020 Annual Population Survey. Comparisons will be provided with data used in the 2006 ES and 2007 ES where appropriate.
4.114 The socio-economic analysis will include assessment of how the Phase 3B development will impact on the existing conditions of the area, including direct and indirect employment generation. It will also include an assessment of the indirect socio-economic impacts of increasing the capacity of the Grain LNG importation facility.
4.115 The assessment will present the quantitative and qualitative evaluations of the social and economic effects of the Phase 3B development and where appropriate will identify the relevant mitigation measures that will be applied during both the construction and operational phases of the Phase 3B development to reduce any potential negative impacts.
RISK
Known Baseline
4.116 During the course of the ~40 years that an LNG Facility has been operating on the Isle of Grain, there has not been a major safety or environmental incident on facility. During this period the site has been required to demonstrate to the HSE and other relevant statutory authorities that the facility is designed, constructed and operated to appropriate Health & Safety and environmental standards.
Potential Impacts
4.117 The mitigation described in 2007 ES Chapter for risk (in accordance with COMAH and HSE frameworks) has continued to be implemented as part of the operation of the Phase 3A development over the last 10 years. Therefore no updates to the environmental information provided in the 2007 ES with respect to Phase 3A are considered necessary for Risk.
4.118 In accordance with the relevant methodology (see below) Risk ES Chapter will include a review of the following impacts during the construction of the Phase 3B tank:
• Hydrology;
• Poor Air Quality;
• Disease Epidemics;
• Industrial Accidents; and
• Manmade Hazards (including pollution accidents, system failures, fires and unexploded ordnance).
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4.119 The Risk ES Chapter will also include a review of the following impacts during the operation of Phase 3B:
• Hydrology;
• Climatological and Metrological risks;
• Extreme temperatures;
• Poor Air Quality;
• Disease Epidemics;
• Industrial Accidents; and
• Manmade Hazards (including pollution accidents, system failures, fires and unexploded ordnance).
Mitigation
4.120 The Risk ES Chapter will consider all mitigation that will already be embedded into the construction and operation of Phase 3B. This includes consideration of the condition discharge reports for Phase 3B, measures that will be incorporated into the CEMP, the Grain LNG site COMAH Safety Report and the Grain LNG Risk Assessment. The Risk ES Chapter will identify any additional mitigation if required.
Assessment Methodology
4.121 There is currently no published guidance for the application of the legal requirements to major accidents and disasters. However, reference will be made to the following documents:
• Guidelines for Environmental Risk Assessment and Management, Defra, 2011; and
• Major Accidents and Disasters in EIA: A Primer, IEMA, 2020,
4.122 Information will also be sourced from the following:
• The Cabinet Office National Risk Register of Civil Emergencies, 2017;
• The International Federation of Red Cross & Red Crescent Societies Early Warning, Early Action, 2008; and
• The International Disaster Database.
4.123 The extent of the study area used for the assessment is the COMAH Consultation Zone.
4.124 Events to be included in the assessment are those which fall within the high consequence category with a low likelihood of occurrence (Figure 4.2 below).
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Figure 4.2 Risk events considered within the scope of this assessment
Source: IEMA – Major Accidents and Disasters – A Primer
4.125 Low consequence events, such as minor spills, will be scoped out as these events are unlikely to result in significant adverse effects as they do not fall into the definition of a major accidents and disasters. Furthermore, high likelihood and high consequence events are also scoped out, as it is assumed that existing legislation and regulatory controls would not permit the project to be progressed under these circumstances.
CLIMATE CHANGE AND GREENHOUSE GASES
Known Baseline
4.126 The United Kingdom’s Climate Impact Programme (UKCIP) highlights the key climate projections over the next 80+ years and these can be summarised as follows:
• Summers will become hotter and drier;
• Winters will become milder and wetter;
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• Soils will become drier on average;
• Snowfall and the number of very cold days will decrease;
• Sea levels will rise; and
• Storms, heavy and extreme rainfall, heatwaves and extreme winds will become more frequent.
4.127 The assessment will establish the climatic data surrounding current seasonal temperatures and precipitation from the Met Office. This data will be used to analyse the current climate and compare these findings, in relation to the Development, to the high emission (RCP 8.5) climate change projections identified in the UK Climate Change Projections 2018 (UKCP18)24. Based on the 25-year lifecycle of the Development, baseline climate change data will be obtained for the 2030s and 2050s.
4.128 The existing Grain LNG importation facility results in the emission of greenhouse gases through its direct operation (including carbon dioxide and methane) and the provision of LNG as a fuel source which results in off-site greenhouse gas emissions through its combustion. However, LNG is recognised as an important fuel to provide a secure and flexible supply of energy to facilitate the transition to a low carbon economy.
Potential Impacts
Climate Change Resilience
4.129 The Phase 3B development will need to be resilient to future climate change. During construction, due to the timescales and nature of the Phase 3B development, the impacts of climate change on the construction of infrastructure and pedestrian comfort of construction workers are predicted to be not significant.
4.130 If climate change resilience is not embedded into operational processes and the design of the Phase 3B development, there will be potential impacts on infrastructure, human receptors and operational procedures.
4.131 Due to the short construction timeframe, climate change impacts due to changes in average climatic conditions are predicted to be minimal.
4.132 During operation, potential climate change impacts may relate to:
• Risks to LNG storage tank and associated infrastructure due to prolonged and higher extreme temperatures;
• Risks to LNG storage tank and associated infrastructure from extreme events including extreme wind;
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• Risks to LNG storage tank and associated infrastructure from tidal flooding due to storm surges and sea level rise;
• Risks to LNG storage tank and associated infrastructure from surface water and fluvial flooding; and
• Risks of site worker travel to and from the site being impacted due to extreme cold and snowfall.
In-Combination Climate Impacts
4.133 Any potentially significant in-combination climate impacts will be considered as part of the Climate Change and Greenhouse Gas ES Chapter based on information provided by the relevant technical consultants.
Greenhouse Gas impacts
4.134 The Phase 3A development has been operational since 2010 and will therefore be considered as part of the GHG baseline. GHG mitigation was previously embedded into the operation of Phase 3A through the 2007 ES Air Quality Chapter.
4.135 The Phase 3B development will release additional greenhouse gases through:
• Construction (including construction transport, the embodied carbon of materials and waste); and
• Operation (through on-site energy consumption, fugitive emissions, transport emissions and off-site LNG combustion).
4.136 Based on the IEMA Greenhouse Gas Assessment criteria, all of these impacts have the potential to be significant (and negative) at the local level. The magnitude of predicted emissions arising from the Development will also be quantified where possible including:
• Quantification of the embodied carbon used for materials during the construction of the Phase 3B development;
• Estimation of transport emissions during construction and operation; and
• Estimation of the Scope 1 and Scope 2 emissions arising from the Phase 3B development will based on the existing register of emissions from Grain LNG Phase 1- 3A.
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Mitigation
4.137 Mitigation measures to address climate change risk will be embedded into the design of the Phase 3B development. Mitigation to reduce greenhouse gas emissions from the Phase 3B development during construction will be embedded into the design and also incorporated into the Construction Transport and Travel Plan (in accordance with Condition 22). In addition, mitigation measures to reduce greenhouse gas emissions during operation will also be embedded into the Phase 3B development’s operations through the Grain LNG site wide Energy Management System. The Climate Change and Greenhouse Gas ES Chapter will outline these measures.
Assessment Methodology
4.138 The assessment will follow guidance within the:
• IEMA EIA Guide to Climate Change Resilience and Adaptation (2020)25; and
• IEMA EIA Guide to Assessing Greenhouse Gas Emissions and Evaluating their Significance (2017)26.
4.139 In accordance with the above guidance documents, the assessment will include:
• An assessment of the climate change resilience of the Phase 3B development;
• An assessment of the greenhouse gas impacts of the Phase 3B development; and
• A description of any predicted in combination climate change impacts with input from relevant technical specialists.
4.140 The climate change resilience assessment will be based primarily on the Phase 3B area.
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FIGURE 1 SITE LOCATION PLAN
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GRAIN LNG PHASE 3B
Redline Area Construction Laydown Area
Greengage Environmental Ltd 9 Holyrood Street, London SE1 2EL
www.greengage-env.com
Fig 1. Location Plan
Project Number 551468 November 2020 1 to 4,000 at A3 Basemap Data: Google Earth National Grid Grain LNG Limited Grain LNG Phase 3B
REFERENCES
1 Ministry of Housing, Communities & Local Government (2019) National Planning Policy Framework 2 Ministry of Housing, Communities & Local Government (2019) Planning Practice Guidance, www.gov.uk/government/collections/planning-practice-guidance 3 Medway Council (2003) Local Plan, www.medway.gov.uk 4 Medway Council (2018) New Local Plan, https://www.medway.gov.uk/info/200149/planning_policies/519/future_medway _local_plan 5 Medway Council (2011); Local Transport Plan. 6 Kent County Council (2017); Kent Local Transport Plan 4. www.kent.gov.uk 7 IEMA (2020) Materials and Waste in EIA 8 Ministry of Housing, Communities & Local Government (2019) Guidance Environmental Impact Assessment 9 The Institute of Environmental Management and Assessment (IEMA), (2004); Guidelines for Environmental Impact Assessment. IEMA. 10 Medway Council, 2011, Op Cit 11 Landscape Institute and Institute of Environmental Management and Assessment, 2013, Guidelines for Landscape and Visual Impact Assessment, Third Edition 12 Tudor, C and Natural England, 2014, An Approach to Landscape Character Assessment 13 Tudor, C and Natural England, 2019, An approach to landscape sensitivity assessment – to inform spatial planning and land management 14 Landscape Institute, 2019, Technical Guidance Note 06/19: Visual Representation of Development Proposals 15 British Standard 5228-1:2009+A1:2014 Code of practice for noise and vibration control on construction and open sites. Noise 16 Holman et al, (2016); ‘IAQM Guidance on the Assessment of Dust from Demolition and Construction V1.1’, Institute of Air Quality Management, London
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17 Moorcroft et al, (2017); ‘Land-Use Planning & Development Control: Planning for Air Quality v1.2’, Environmental Protection and Institute of Air Quality Management, London 18 Department for Environment, Food and Rural Affairs, (2018); ‘Local Air Quality Management: Technical Guidance (TG16)’, London: Crown. 19 Environment Agency and Department for Environment, Food & Rural Affairs, (2016); ‘Air Emissions Risk Assessment for Your Environmental Permit’ [Online]. [30 October 2020]. Available from: https://www.gov.uk/guidance/air-emissions-risk- assessment-for-your-environmental-permit 20 Newcastle University, (2015); Travel to Work Areas, United Kingdom, 2011. https://ons.maps.arcgis.com/apps/MapSeries/index.html?appid=397ccae5d5c74 72e87cf0ca766386cc2 21 ONS (2011) 2011 Census: Usual resident population (KS101EW) Medway, www.nomisweb.co.uk 22 ONS (2011) 2011 Census: Economic Activity (KS601EW) Medway, South East, England. www.nomisweb.co.uk 23 ONS (2011) Qualifications and students (KS501EW) Medway, Southeast, England, www.nomisweb.co.uk 24 UKCIP (2018) Climate Change Projections 25 IEMA (2020) EIA Guide to Climate Change Resilience and Adaptation 26 IEMA (2017) EIA Guide to Assessing Greenhouse Gas Emissions and Evaluating their Significance
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