GRIDLINK INTERCONNECTOR Scoping Report for a Marine Environmental Appraisal
P2114_R4493_Rev2 | 16 August 2018
Intertek Energy & Water Consultancy Services Exchange House, Station Road, Liphook, Hampshire GU30 7DW, United Kingdom GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
DOCUMENT RELEASE FORM
GridLink Interconnector P2114_R4493_Rev2 Scoping Report for a Marine Environmental Appraisal
Author/s
Jill Hobbs
Project Manager Authoriser
Anna Farley Anna Farley
Rev No Date Reason Author Checker Authoriser Rev 0 24/05/2018 Draft JH AF AF Rev 1 29/06/2018 Addressing client comments JH AF AF Rev 2 16/08/2018 Final for issue JH AF AF
Intertek Energy & Water Consultancy Services is the trading name of Metoc Ltd, a member of the Intertek group of companies.
I P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
CONTENTS
DOCUMENT RELEASE FORM I
1. INTRODUCTION 1 1.1 Background 1 1.2 Scoping Opinion 1
2. THE PROPOSED DEVELOPMENT 3 2.1 Background 3 2.2 French Components of GridLink 3 2.3 Overview of the Proposed Development 3 2.4 Subsea HVDC Cables 8 2.5 Shore Crossing 14 2.6 Converter Station 15 2.7 Onshore HVAC Cables to NGET Kingsnorth Sub-station 17 2.8 Environmental Management of Construction of the Proposed Development 18 2.9 Operation and Maintenance of the Proposed Development 19 2.10 Decommissioning 20
3. REGULATORY CONTEXT 21 3.1 Introduction 21 3.2 Need for EIA in the UK 21 3.3 Need for EIA in France 21
4. SCOPING METHODOLOGY 22 4.1 Introduction 22 4.2 Scoping Methodology 22 4.3 Consultation 24
5. SEABED SEDIMENTS AND PHYSICAL PROCESSES 26 5.1 Introduction 26 5.2 Baseline Conditions 26 5.3 Mitigation Measures 28 5.4 Potential Effects to be Excluded from the EA 28
II P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
5.5 Potential Effects to be Included in the EA 29 5.6 Additional Baseline Information and Collection Methods 30 5.7 Appraisal of Potential Effects 30
6. PROTECTED SITES FOR NATURE CONSERVATION 31 6.1 Introduction 31 6.2 Protected Sites for Nature Conservation 31 6.3 Preliminary Consultations with Natural England and Joint Nature Conservation Committee 43 6.4 Appraisal of Potential Effects 43 6.5 Habitats Regulation Appraisal 44 6.6 Marine and Conservation Zone Assessment 44
7. BENTHIC ECOLOGY 46 7.1 Introduction 46 7.2 Baseline Conditions 46 7.3 Mitigation Measures 47 7.4 Potential Effects to be Excluded from the EA 47 7.5 Potential Effects to be Included in the EA 48 7.6 Additional Baseline Information and Collection Methods 49 7.7 Appraisal of Potential Effects 50
8. MARINE AND COASTAL BIRDS 51 8.1 Introduction 51 8.2 Baseline Conditions 51 8.3 Mitigation Measures 52 8.4 Potential Effects to be Excluded from the EA 52 8.5 Potential Effects to be Included in the EA 53 8.6 Additional Baseline Information and Collection Methods 53 8.7 Appraisal of Potential Effects 54
9. MARINE MAMMALS 55 9.1 Introduction 55 9.2 Baseline Conditions 55 9.3 Mitigation Measures 57 9.4 Potential Effects to be Excluded from the EA 57
III P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
9.5 Potential Effects to be Included in the EA 58 9.6 Additional Baseline Information and Collection Methods 58 9.7 Appraisal of Potential Effects 59
10. FISHERIES 60 10.1 Introduction 60 10.2 Baseline Conditions 60 10.3 Mitigation Measures 66 10.4 Potential Effects to be Excluded from the EA 67 10.5 Potential Effects to be Included in the EA 68 10.6 Additional Baseline Information and Collection Methods 69 10.7 Appraisal of Potential Effects 70
11. HISTORIC ENVIRONMENT 71 11.1 Introduction 71 11.2 Baseline Conditions 71 11.3 Mitigation Measures 83 11.4 Potential Effects to be Excluded from the EA 84 11.5 Potential Effects to be Included in the EA 84 11.6 Additional Baseline Information and Collection Methods 84 11.7 Appraisal of Potential Effects 85
12. OTHER ENVIRONMENT ISSUES 86 12.1 Introduction 86 12.2 Water Quality 86 12.3 Shipping and Navigation 87 12.4 Third Party Infrastructure 88 12.5 Other Marine Users 88 12.6 Air Quality 88
13. SUMMARY 89 13.1 Scoping of Potential Effects of the Proposed Development 89 13.2 EA Structure 89 13.3 Impact Assessment Methodology 90 13.4 Cumulative Effects Assessment 95
IV P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
LIST OF TABLES AND FIGURES
Tables Table 4-1 Pressure Description 23 Table 4-2 Consultations Undertaken to Date 24 Table 5-1 Effects on Seabed Sediments and Physical Processes to be Excluded from the EA 29 Table 5-2 Effects on Seabed Sediments and Physical Processes to be Included in the EA 29 Table 6-1 Natura 2000 sites crossed or within 10 km of the Proposed Development 32 Table 6-2 NATURA 2000 sites crossed or within 10 km of the Proposed Development 40 Table 7-1 Effects on Benthic Ecology to be Excluded from the EA 48 Table 7-2 Effects on Benthic Ecology to be Included in the EA 48 Table 8-1 Effects on Marine and Coastal Birds to be Excluded from the EA 52 Table 8-2 Effects on Marine and Coastal Birds to be Included in the EA 53 Table 9-1 Effects on Marine Mammals to be Excluded from the EA 57 Table 9-2 Effects on Marine Mammals to be Included from the EA 58 Table 10-1 Fish Species with Spawning and/or Nursery Grounds within the cable route 61 Table 10-2 Landing Values by Generic Species Types for ICES Rectangle 31F0 66 Table 10-3 Landing values by Generic Species Types for ICES Rectangle 31F1 66 Table 10-4 Effects on Fisheries to be Excluded from the EA 67 Table 10-5 Effects on Fisheries to be Included from the EA 68 Table 11-1 The details of the wrecks which are of particular interest (two of which are designated wrecks under the Protection of Wrecks Act) in the UKHO records are presented in Figures 11-7 to Figure 11-9.Known and Potential Marine Archaeological Receptors within 2 km of the Cable Route 73 Table 11-2 Known and Potential Marine Archaeological Receptors by Area 73 Table 11-3 Effects on Fisheries to be Excluded from the EA 84 Table 13-1 Summary of the Pressures to be Included Within the EA 89 Table 13-2 Criteria for characterising the magnitude of the impact 92 Table 13-3 Criteria for characterising the sensitivity of the receptor (receptor value) 93 Table 13-4 Significance matrix 94 Table 13-5 Definitions of significance levels 94
Figures Schematic of the GridLink project 3
V P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Overview of the GridLink project 5 Alternative subsea cables routes in outer Thames Estuary 7 Cross-sections of subsea HVDC cable and bundled cable configuration 8 Schematic sectional view of the trench of the submarine cable 9 Schematic sectional view of rock placement over the submarine cable where seabed trenching is not feasible 10 Schematic sectional view of placement of concrete mattresses at crossing of third party infrastructure with protection by rock placement 10 Typical cable-lay vessel used to lay the subsea electricity cables 13 Typical cable-lay barge used to lay the subsea electricity cables 13 Profile of HDD shore crossing at Kingsnorth 14 Profile of HDD shore crossing at Kingsnorth 15 Illustration of HDD process 15 Converter station site within the Kingsnorth industrial area 16 Example of converter station design 16 Figure 2-15 Location of GridLink converter station and National Grid Kingsnorth 400 kV sub-station 17 Figure 2-16 Schematic of alternative configurations of underground double-circuit HVAC cable 18 Schematic Sediment Transport Pathways5 28 Medway Bass Nursery Area 62 Spawning and Nursery Grounds 63 Shellfish waters 65 Archaeological and Cultural Heritage Receptors Identified in the Intertidal Zone 72 Archaeological and Cultural Heritage Receptors Identified in the Medway Estuary 74 Archaeological and Cultural Heritage Receptors Identified in the Outer Thames Estuary Section 1 75 Archaeological and Cultural Heritage Receptors Identified in the Outer Thames Estuary Section 2 76 Archaeological and Cultural Heritage Receptors Identified in the Outer Thames Estuary Section 3 77 Archaeological and Cultural Heritage Receptors Identified in the southern North Sea 78 Potentially Important Wrecks and Aircraft Crashes in the Medway Estuary and Outer Thames Estuary 79 Potentially Important Wrecks and Aircraft Crashes in the Outer Thames Estuary 80 Potentially Important Wrecks and Aircraft Crashes in the southern North Sea 81
VI P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
1. INTRODUCTION 1.1 Background GridLink Interconnector Limited (herein referred to as the “Applicant”) is intending to submit an application for a Marine Licence for the construction, operation and maintenance of a new electricity interconnector (herein referred to as “GridLink”) under the Marine and Coastal Access Act 2009, which will connect the UK and French electricity networks at Kingsnorth in Kent and Dunkerque in Nord region of France respectively. GridLink will be a high voltage direct current (HVDC) electricity interconnector with an approximate capacity of 1,400 megawatts (MW). HVDC is the most effective technology for the import or export of electricity over significant distances, with the system experiencing lower losses than an alternating current (AC) system. It requires a converter station at each end on the interconnector to convert the HVDC power to high voltage alternating current (HVAC) power for use within the UK and French national electricity networks. GridLink will be approximately 140 km long, connecting to the UK transmission system at National Grid’s Kingsnorth 400 kV substation in Kent and the French transmission system at the RTE Warande 400 kV substation in the Nord region of France. The operation of an electricity interconnector is a licensable activity under Section 6(1) of the Electricity Act 1989 (as amended). The Applicant is a holder of an electricity interconnector licence, which was granted on 20 December 2016, under the Act. The European Union has agreed its 2030 energy and climate framework, which refers to Member States achieving 10% interconnection by 2020 and aiming for 15% by 2030. GridLink will contribute to increasing the capacity of interconnection in UK and France to a level of 10% and will enable the import and export of electricity between the two countries. The European Union Regulation on Guidelines for Trans-European Energy Infrastructure (EU 347/2013), known as the TEN-E Regulations, applies to the whole Proposed Development from the converter station in France to the converter station in the UK. The TEN-E Regulations provides a framework for consenting the Proposed Development as a whole. 1.2 Scoping Opinion The Applicant recognises that they will be required to provide environmental supporting information in support of their Marine License application. For example, the application requires applicants to demonstrate the effects of the project on European sites, Marine Conservation Zones, Sites of Special Scientific Interest (SSSI) have been considered; and that the effects of the project have been considered in accordance with the Water Framework Directive. In addition, the MMO will consult with statutory consultees to ensure that due consideration has been given to navigational safety, the historic environment and other marine stakeholders. In addition, to the above requirements, as an interconnector license holder, the Applicant has a duty to preserve amenity. Therefore, as best practice and to ensure environmental assessment is provided to the MMO and statutory consultees in a consolidated and concise manner, the Applicant intends carrying out an Environmental Appraisal (EA) and propose submitting a non-statutory Environmental Report (ER) to support the Marine Licence application. This report provides the MMO and key consultees an opportunity to facilitate their representations regarding the scope of the EA. The specific objectives of this Scoping Report are to:
1 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
1. Describe the nature of the proposed development; 2. Provide a brief baseline for each environmental topic; 3. Describe the likely effects of the proposed development on each topic, including identifying those that are potentially significant. Topics or issues that are proposed to be scoped out of the EA are also described; and 4. Provide the scope of assessment for each topic to be included in the EA.
2 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
2. THE PROPOSED DEVELOPMENT 2.1 Background This chapter provides a description of the wider project and a more detailed description of those elements which will be the subject of the application for a Marine Licence. The Proposed Development is a 1,400 MW at ±525 kV bipole HVDC electricity interconnector between the UK and France. A schematic of the GridLink project is shown in Figure 2-1.
Schematic of the GridLink project
2.2 French Components of GridLink The subsea cable between the UK and French landfalls is approximately 140 km in length. The HVDC cables will make landfall to the northeast of the Port of Dunkerque and from this location approximately 13 km of underground HVDC cables will be laid through predominantly port and agricultural land between the landfall and the converter station. The HVDC converter station is proposed to be located in land designated for heavy industry within the Port of Dunkerque approximately 3 km from the existing RTE Warande 400 kV substation to the south of Dunkerque. The connection by underground HVAC cables between the converter station and sub-station will be implemented by RTE. The subsea cable within French territorial waters and the associated onshore infrastructure in France is subject to the separate consenting regime of France, and therefore it does not form part of this Scoping Report. 2.3 Overview of the Proposed Development The elements of the Proposed Development comprise the following: ▪ Installation and operation of a 1,400 MW High Voltage Direct Current (HVDC) subsea cable between the converter station at Kingsnorth and a similar converter station at a site in Dunkerque, France. The cable will travel from Kingsnorth down the Medway Estuary, through the Thames Estuary, along the north Kent coast around Margate and across the southern North Sea up to the UK/France median line. The cable will then cross into French territorial waters, making landfall at Dunkerque in the Nord region of France;
3 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
▪ Construction and operation of a convertor station at a 4.5 hectare site in the Kingsnorth industrial area. The converter station will convert electricity from direct current to alternating current to allow feed-in to the National Grid at the National Grid Kingsnorth 400 kV sub-station. The converter station will use Voltage Source Converter-High Voltage Direct Current (VSC-HVDC) technology; ▪ Installation and operation of an underground High Voltage Alternating Current (HVAC) cable between the converter station and the National Grid Kingsnorth 400 kV substation. The converter station sites and cable route have been identified through a comprehensive evaluation of alternatives, site selection and cable routing process incorporating environmental, technical and economic criteria. This process has included consideration of alternative sites, landfalls and onshore and offshore HVDC and HVAC cable routes. Currently, the offshore cable route in the outer Thames Estuary is subject to an ongoing evaluation of alternatives: two alternative routes are available to the north and south of the existing BritNed interconnector cable that connects the UK to the Netherlands. Whilst both alternatives are technically and environmentally feasible, in order to reduce cable length and avoid two crossings of the BritNed cable, the preferred cable route is to the south of the BritNed cable. The final selection will be determined after coordination with BritNed and the Port of London Authority. In addition, the final offshore cable route will be optimised to take into account environmental considerations, the requirements of statutory authorities and landowners, and the results of the geophysical and geotechnical surveys of the seabed within a 500 m corridor (250 m either side of the cable route centreline). Whichever cable route is selected in the outer Thames Estuary, the HVDC subsea cable length between the converter stations is approximately 140 km, comprising 108 km in UK waters and 32 km in French waters. The UK converter station site is located in the London Medway Commercial Park within the Kingsnorth industrial area approximately 200 m from the shoreline. The subsea HVDC cable will cross the shoreline by Horizontal Directional Drilling (HDD) to pass underneath the intertidal zone, an existing flood defence bund and nature conservation area. The HDD will emerge at the surface directly at the converter station site, so that there is no requirement for any onshore HVDC cable installation. Approximately 3 km of underground HVAC onshore cable will be installed from the converter station to the existing National Grid 400 kV sub-station at the former E.on coal-fired power station site in Kingsnorth. The underground HVAC cable route will be installed under roads or roadside verges. No new overhead electricity transmission lines will be constructed for the GridLink project. An overview of the GridLink project is shown in Figure 2-2.
4 P2114_R4493_Rev2 | 16 August 2018
360000 400000 440000 GRIDLINK INTERCONNECTOR SCOPING REPORT . Figure 2-2: Project Overview . Legend Converter Station 0 0 0 0 0 0 'South of BritNed' Preferred HVDC Cable Route 0 0 2 2 7 7
5 5 'North of BritNed' Alternative HVDC Cable Route Onshore Route Median Line 12nm Territorial Sea Limit 0 0 0 0 0 0 0 0 8 8 6 6 5 5
NOTE: Not to be used for Navigation
Date Thursday, June 28, 2018 14:38:22 Projection WGS_1984_UTM_Zone_31N Spheroid WGS_1984 Datum D_WGS_1984
Data Source ESRI, ELANENERGY, CDA, UKHO 0 0 0 0
0 0 J:\P2114\Mxd\Scoping_Report\ 0 0 File Reference
4 4 Fig_2_1_Project_Overview.mxd 6 6 5 5 Created By Richard Marlow Reviewed By Jennifer Arthur Approved By Anna Farley
km © Metoc Ltd, 2018. 360000 400000 440000 0 5.5 11 16.5 22 All rights reserved. © Esri, 2018; © Crown Copyright. Contains public sector information licensed under Open Government Licence v3.0. Contains public sector information, licensed under the Open Government Licence v2.0, from the UKHO, 2013. GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
There are two alternative subsea cable routes in the outer Thames Estuary, as shown in Figure 2-3. The routes share a common centreline from Kingsnorth to approximately kilometre point (KP) 13, where they diverge to run either side of the BritNed cable before re-joining at approximately KP57: ▪ ‘South of BritNed’ base case – The cable route lies to the south of the existing BritNed interconnector with a separation distance of approximately 300 m, closing to approximately 150 m at two points due to construction constraints, i.e. Peel Port Great Nore anchorage and a shallow island feature; ▪ ‘North of BritNed’ alternative – The cable route crosses the BritNed cable and then follows the northern side of the Port of London Authority shipping channels, re-crossing the shipping channel and the BritNed cable at approximately KP55. For the purposes of scoping the potential environmental impacts, both subsea cable routes have been evaluated. The subsea cables will be laid within a 30 m corridor that is subject to a Crown Estate license and easement from Peel Ports (for the Medway Estuary only). The final route will be determined within a 500 m corridor (250 m either side of centreline of nominal cable route) after bathymetric, geophysical, geotechnical and environmental surveys have been completed.
6 P2114_R4493_Rev2 | 16 August 2018
350000 375000 GRIDLINK INTERCONNECTOR SCOPING REPORT Figure 2-3: Alternative Subsea Cable Routes . in the Outer Thames Estuary . Legend 0 0 0 0
0 0 'South of BritNed' Preferred HVDC Cable Route 5 5 2 2
7 7 'North of BritNed' Alternative HVDC Cable Route 5 5 Median Line 0 0 0 0 0 0 0 0 0 0 7 7 5 5
NOTE: Not to be used for Navigation
Date Tuesday, June 26, 2018 10:26:06 Projection WGS_1984_UTM_Zone_31N Spheroid WGS_1984 Datum D_WGS_1984
Data Source ESRI, ELANENERGY, CDA, UKHO
J:\P2114\Mxd\Scoping_Report\ File Reference Fig_2_3_Thames_Estuary_Alternative_Routes.mxd Created By Richard Marlow Reviewed By Jennifer Arthur
0 0 Approved By Anna Farley 0 0 0 0 5 5 7 7 6 6 5 5
km © Metoc Ltd, 2018. 350000 375000 0 3 6 9 12 All rights reserved. © Esri, 2018; © Crown Copyright. Contains public sector information licensed under Open Government Licence v3.0. Contains public sector information, licensed under the Open Government Licence v2.0, from the UKHO, 2013. GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
2.4 Subsea HVDC Cables The subsea cable will consist of two high voltage direct current (HVDC) cables of polyethylene (XLPE) or mass impregnated (MI) construction. The diameter of each cable will be approximately 150 mm, with a central part made of copper or aluminium. The cables will be protected to prevent damage by steel wire armouring and an outer sheath. The two cables will be bundled together for cable-lay into a single trench. A smaller fibre-optic cable will be included with the bundled HVDC cables for monitoring and control purposes. An illustration of the subsea HVDC cables is shown in Figure 2-4. Cross-sections of subsea HVDC cable and bundled cable configuration
The cables will be buried bundled together in the same trench at a depth of approximately 2 m below the seabed, increasing to 3 m depending on the geological conditions, in order to protect the cable. Where sand waves are present, the burial depth may be increased further to prevent exposure due to mobile seabed conditions. The offshore geophysical and geotechnical survey will identify the geological conditions and units along the cable route. Based on the results of the survey, a burial risk assessment will be carried out to determine the appropriate burial depth to protect the cable. The illustrative sectional view of the subsea trench is provided in Figure 2-5.
8 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Schematic sectional view of the trench of the submarine cable
In case a geological unit does not allow burial of the cable, the cable will be protected by rock placement or a mattress or similar technique in accordance with Good Industry Practice. At crossings of existing submarine cables, the existing cables will be protected by a mattress allowing the new cables to pass over the top in accordance with Good Industry Practice. The new cables will then be protected by rock placement or similar technique. The trenching below the seabed and/or rock protection will ensure that the cable is not exposed to damage from natural phenomena (sediment transport, extreme weather, tidal or other sea conditions, etc) or human activities (anchoring of vessels or fishing nets). The illustrative sectional view of rock protection and concrete mattress at a third-party crossing is provided in Figure 2-6 and Figure 2-7 respectively.
9 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Schematic sectional view of rock placement over the submarine cable where seabed trenching is not feasible
Schematic sectional view of placement of concrete mattresses at crossing of third party infrastructure with protection by rock placement
The cable installation techniques, including the methods to be used for trenching, cable installation and backfilling, will be determined after the offshore bathymetrical, geophysical, geotechnical and environmental survey and engineering studies have been completed. Different cable installation and burial techniques will be used depending on geological seabed conditions, water depth and environmental considerations along the cable route, in particular the suitability of seabed soil types (granulometry, cohesiveness, density) and maximum operational soil shear strength. Trenching may not be possible in short sections where hard seabed geological units are found, or where surface laid protection such as rock placement or concrete mattressing is required, for example at third party infrastructure crossings. The offshore bathymetrical, geophysical, geotechnical and environmental survey is designed to detect any significant seabed features and obstacles that may be unexploded ordnance (UXO) within the 500 m survey corridor. The cable route will be micro-routed within this corridor with a suitable safety distance away from any UXO finds so that no UXO clearance is necessary. A more detailed pre-construction survey will further investigate the potential for UXO finds along the cable route prior to cable installation. If a potential UXO cannot be avoided for whatsoever reason, clearance
10 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
works will be carried out prior to cable installation by recovery using an electromagnetic grab where safe or otherwise detonation as a last resort. In areas of high mobility sediments and sand waves, pre-sweeping may be carried out prior to cable installation to create a path to enable trenching to the required depth. If required, pre-sweeping by dredging will reduce the height of the sandwaves along the cable route to allow control of the cable burial depth and provide more resistance to sandwave mobility. The spoil volumes resulting from any pre-sweeping will be small and similar to dredging operations for channel or port maintenance, and deposited back on the seabed in the immediate vicinity of the pre-sweeping activity. Cable installation techniques may include trenching before cable installation (pre-lay), simultaneously with the cable installation or after cable installation (post-lay). Pre-lay dredging may be used in non-cohesive soil types, consisting of the pre-lay excavation of a trench prior to cable installation by a dredger, such as a suction hopper dredger, potentially with post-lay mechanical backfilling to provide complete cover over the cable following installation. However, given the nature of the soils along the cable route, the use of pre-lay dredging is expected to be limited. Mechanical trenching may be used to excavate the trench in hard soils, including rock, either pre-lay or simultaneously with the cable installation. Mechanical trenchers are usually mounted on tracked vehicles and use chain saws or wheels with tungsten carbide teeth to cut a defined trench. After cable installation, the trench may be backfilled or recover over time by natural sedimentation. The suitability of this technique depends on the density of the material and the ability of the machine to displace it. Due to the soil conditions along the cable route (where hard rock is generally absent), it is unlikely that there will be a significant need for mechanical trenching but it may be used in gravelly seabed sediments. Jetting trenchers, mounted on a self-propelled remotely operated vehicle (ROV) or towed or coupled to a mechanical trencher, may be used in soft clays and sands typically less than 2 mm particle size. The technique uses water jets to fluidise the seabed and form a trench full of fluidised material so that the cable sinks into the trench through the fluidised material under its own weight or by direction. The jetting action may be augmented by temporary removal of some material out of the trench. The trench created may be partially or completely filled by reconsolidation of the fluidised material, or recover over time through natural sedimentation. For the cable route, a specialised jetting trencher may be required for the intertidal and shallow water sections. Cable ploughing could provide simultaneous cable lay or post-lay trenching. However, although cable ploughing minimises soil disturbance due to the speed of the operation in both creating and backfilling the trench, ploughing has significant risks of cable damage, especially for bundled cables. Therefore, cable ploughing is not considered a suitable cable installation technique. In summary, the trenching techniques used for the subsea cables are expected to be: ▪ Pre-lay dredging – limited use to UK landfall, Medway Estuary and in specific areas of non- cohesive soils; ▪ Mechanical trenchers – general use for gravelly soils; ▪ Jetting trenchers – general use for sand and mud soils, and also intertidal and shallow waters such as the Medway Estuary. None of the alternative cable installation techniques require dredging with disposal of dredged material, as any displaced or excavated material is intended to be reused as backfill to cover the trench. The bundled cable is installed in the trench from a cable-lay vessel. The cable is fed from an on- board spool to over-board at the aft of the vessel. The cable is guided, under hold-back tension, into
11 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
the water to be laid into the pre-lay trench, simultaneously fed to the trenching machine or laid onto the seabed for post-lay trenching and burial. When the cable on the spool is exhausted, the empty spool is replaced with a new full spool and cable lay continues. The cable ends are jointed together to continue as a single, integrated cable system. If the cables are not able to be buried, for example in hard rock seabed conditions or at crossings of existing submarine cables, the cables will be laid on the seabed (or on top of mattresses provided to cover third party infrastructure at crossing points) and protected by rock placement or similar technique. For rock placement, a continuous berm of graded rock will be deposited so as to protect the cable from bottom trawling, anchor drops or anchor drags, dredging, etc. Rock placement will also prevent the cable laid on the seabed from causing scour or changing sedimentation patterns. The cable installation vessels are operated using a dynamic positioning system of thrusters and anchors. Such vessels use multiple propulsion systems to maintain the correct position and alignment. Anchoring may also be employed, using a series of four to six anchors with each anchor 1 to 3 m wide placed within a 10 m radius anchor site. To provide stability for the cable-lay, the anchors are arranged in an anchor spread in accordance with DNV GL-ST-N-001 Marine operations and marine warranty (June/November 2016), supplemented by 0035ND Guidelines for offshore wind farm infrastructure installation (June 2016). The anchors are located a minimum of 100 m away from any existing subsea infrastructure, increasing to 300 m if the potential anchor drag path is towards the infrastructure. A combination of anchored or dynamically positioned vessels may be used, depending on the depth of the draught, the physical condition of the seabed, and navigational restrictions. Depending on the techniques chosen, the cable trenching and installation speed can vary from 200 to 400 m per hour (5 to 9 km per day). In addition, where cable joints are required, the cable-lay vessel may remain stationary to conduct the jointing for up to 10 days. The work to lay the cable will be carried out for 24 hours a day, in order to minimise the impact on navigation and other sea users. This will also allow the installation period to be optimised depending on weather conditions. There are a range of different vessels that may be used for the cable installation, depending on the construction contractor selected for the works. In addition to the cable-laying vessels themselves, research, supply and safety vessels will also be required. Other users of the sea will be notified in accordance with the regulatory procedures which apply, and in collaboration with the French Préfecture Maritime for the Channel and North Sea and UK Port of London Authority and Peel Ports, to guarantee safety for navigation and for the cable-laying works. An example of a typical cable-lay vessel for deep water is shown in Figure 2-8, and a typical cable-lay barge for shallower water is shown in Figure 2-9.
12 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Typical cable-lay vessel used to lay the subsea electricity cables
(source: NKT) Typical cable-lay barge used to lay the subsea electricity cables
(source: NKT)
13 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
2.5 Shore Crossing The shoreline at Kingsnorth in the Medway Estuary will be crossed by horizontal directional drilling (HDD), comprising the drilling of two horizontal boreholes below the intertidal mud-flats, flood defence bund and nature conservation area. The choice of horizontal directional drilling technique ensures that there is no surface disturbance. The horizontal drilling machine will be installed on the landward side, and the drilling will follow an elliptical trajectory at an angle of about 8 to 12°, passing 10-15 m beneath the shoreline and emerging after the low water mark. The HDD length will be approximately 700 m. The converter station site is located approximately 200 m from the shoreline, therefore the HDD drilling rig will be installed at the converter station site. Hence, the subsea cable will emerge from the HDD at the converter station and no underground HVDC cables at Kingsnorth are required. The alignment of the HDD is shown in Figure 2-10. Profile of HDD shore crossing at Kingsnorth
The profile of the HDD under the Kingsnorth shoreline is shown in Figure 2-11.
14 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Profile of HDD shore crossing at Kingsnorth
The HDD process comprises four steps for each borehole: 1. Drilling of a pilot hole by the HDD drilling rig located at the converter station 2. Reaming to enlarge the borehole to sufficient size to accommodate the cable 3. Installation of a duct to line the borehole 4. Pulling of the subsea cable through the pre-installed duct from the cable-lay vessel/barge When the offshore cable-lay approaches the landfall, the subsea cables will be unbundled and separated to allow each cable to be pulled through its own HDD borehole duct. An illustration of the HDD process is shown in Figure 2-12. Illustration of HDD process
2.6 Converter Station The converter station converts direct current to alternating current and vice versa for connection to the UK national grid. The converter station will occupy a site of approximately 4.5 hectares. The electrical equipment is mostly installed in buildings. The maximum building height is 25 m and outdoor equipment may be up to 15 m high. Buildings, outdoor equipment and landscaping will be surrounded by a perimeter security fence. The converter station site is within the Kingsnorth industrial zone known as the Medway Commercial Park, approximately 200 m from the shoreline of the Medway Estuary. The location of the converter station site is shown in Figure 2-13.
15 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
The indicative design of the converter station is provided in Figure 2-14. Converter station site within the Kingsnorth industrial area
Example of converter station design
(source: Siemens Aktiengesellschaft) There are no heat generation, combustion, chemical processes or electricity production activities at the converter station, except for an emergency diesel generator to provide local power to the station in the event of a failure of the mains supply. Noise emissions are also limited, due to the absence of mechanical or rotating machinery or other significant sources of noise. The main electrical equipment will be located inside buildings to provide additional noise attenuation and mitigation. Exterior lighting is only required for operational supervision and security purposes, for example to illuminate site entrance, walkways, operator interfaces and critical or hazardous plant areas. Such
16 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
lighting will be controlled to avoid unnecessary illumination of areas outside the site boundary and minimise any glare and the spread of upward and sideways light. 2.7 Onshore HVAC Cables to NGET Kingsnorth Sub-station The connection point to the UK national electricity grid is defined by National Grid as the cable sealing ends of Spare Bay 3 allocated to GridLink at the Kingsnorth 400 kV sub-station. No extension to the sub-station is necessary to accommodate the connection of GridLink. The connection requires creation of a single-circuit or double-circuit, 400 kV alternating current link laid underground from the GridLink converter station to the Kingsnorth sub-station. The underground cables will be located within the Kingsnorth industrial area, where they will be placed under roads, footpath/verge or adjacent to the easements of other underground cables to reach the sub-station. The cable route and connection point at the sub-station are shown in Figure 2-15.
Figure 2-15 Location of GridLink converter station and National Grid Kingsnorth 400 kV sub-station
The HVAC cable connection to the National Grid Kingsnorth 400 kV sub-station may comprise one or two circuits. Each circuit will consist of three conductor cables, each cable providing one of the three phases of an electrical circuit. The enamelled copper wire cables will have a cross-section of 1,800 to 3,500 mm², depending on the number of circuits. The cables may be laid in HDPE (high-density polyethylene) ducts. The circuit(s) will be laid in a trench approximately 1.5 m deep and 2 m wide. A protective layer of concrete blocks and a warning layer will be placed above the circuits to indicate the presence of the cables. Depending on the number or circuits and final design of the cable, taking into account ground conditions, third-party crossings, etc, the conductor cables may be installed in flat formation or trefoil configuration, as illustrated in Figure 2-16.
17 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Figure 2-16 Schematic of alternative configurations of underground double- circuit HVAC cable
2.8 Environmental Management of Construction of the Proposed Development Construction of the subsea cable comprises mobilisation of the vessels required for the cable-lay spread, including survey vessels, guard vessels, supply vessels, cable-lay vessels and barges and associated victualling and port-related services. The cable-lay process will include pre-lay survey, sand wave sweeping (if required), pre- or post-lay trenching, cable installation, post-lay burial and seabed intervention works, such as rock placement, and post-lay survey. Construction of the converter station comprises civil works for site preparation and foundations, erection of a steel-frame buildings, installation of the HVDC and HVAC electrical equipment and completion of balance of plant and site services. A temporary construction lay down area of approximately 2 hectares will be established on vacant industrial land in the vicinity of the converter station site at Kingsnorth. This area will be returned to its previous condition following completion of construction works. Prior to commencement of construction activities, the Principal Contractor(s) will be required to prepare a Construction Environmental Management Plan (CEMP) and associated implementing procedures. The CEMP will identify control measures to prevent pollution of air, water or
18 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
soil/seabed, manage waste and materials storage, and any permit requirements imposed on the carrying out of these activities. The CEMP will include, as a minimum, the following contents: 1. Environmental policy; 2. Roles and responsibilities of key members of the contractors team; 3. Environmental management and mitigation measures; 4. Consultation and communication strategy; 5. Induction and training strategy; 6. Monitoring and auditing strategy; 7. Non-compliance, corrective and preventative actions procedures. The construction worker induction program will include requirements related to environmental and ecological sensitivities of the subsea cable route and converter station site, their surroundings and actions they should take to reduce potential effects, including identification of potential receptors at worksites and in the vicinity, including qualifying species, and any restrictions on hours of work or methods of work. 2.9 Operation and Maintenance of the Proposed Development In operation, the converter station is managed from a control room, which may be installed on site or elsewhere. A small number of operators will also be present on-site to carry out inspection, maintenance and safety checks. The safety of the station is monitored continuously from the control room to ensure the operations proceed correctly and reliably, and to allow a fast response if any unforeseen incident or emergency should occur. When operational, the transport of electricity through the subsea HVDC cable will generate very low electromagnetic fields (EMF), which are similar in nature and magnitude to the earth’s magnetic field. EMF is limited in the subsea HVDC cable due to the direct current flow and bipole configuration, which means magnetic fields in each cable act to cancel each other out due to the different polarities in each cable. For both the subsea HVDC cable and onshore HVAC cable, the conductors are contained within a metallic outer sheath, which prevent any external electric fields. Therefore, there is no significant change to EMF outside the subsea or onshore cable trenches. Once installed, the subsea cable is designed to require minimal maintenance during its operational lifetime. In the unlikely event of a cable fault a cable repair will be necessary which typically involves recovering a section of the cable, cutting out the faulty section and adding a new section of cable and returning to the seabed for reburial. Depending on the seabed conditions and location of repair rock / concrete mattress protection may also be required. The operations involved will be similar to those during construction but on a lesser scale. Maintenance activities may include inspection surveys to monitor the depth of burial along the cable route and / or any sections of exposed cable; re-burial of exposed cable sections; and reinstatement of any displaced rock or concrete mattressing. These activities will be similar to construction activities but again on a lesser scale. For the purposes of this scoping report (and in line with terminology used by the MMO) repair and maintenance has been collectively referred to as maintenance.
19 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
2.10 Decommissioning After the operational lifetime, the subsea cable will be decommissioned in accordance with applicable industry guidelines, e.g. European Subsea Cables Association guidelines, International Cable Protection Committee (ICPC) Recommendations and guidance notes from similar industries e.g. offshore renewables. The preliminary decommissioning plan assumes recovery and removal of the subsea and onshore cables, and demolition of the converter station. However, the decommissioning plan will be flexible to adopt the least environmentally damaging option, such as leaving the cables in-situ, as may be determined at the time when decommissioning becomes necessary. The decommissioning plan will take into account all permit requirements and contractual commitments to land-owners made on behalf of GridLink.
20 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
3. REGULATORY CONTEXT 3.1 Introduction The laying of power cables within the UK territorial waters (between mean high-water springs tidal mark and 12 nautical miles offshore) requires a Marine Licence under the Marine and Coastal Access Act 2009. The laying of any cable beyond the UK territorial waters does not require a Marine Licence, however, associated works such as pre-lay dredge and disposal and cable protection measures may require a Marine Licence. The Marine Management Organisation (MMO) are obliged to grant a Marine Licence (within UK territorial waters) for power cable applications, however, environmental information can be requested by them to support the application and conditions can be included in any Marine Licence issued. The environmental information prepared to support a Marine Licence application will also be used to support other consent and licence applications, such as River Works Licences. 3.2 Need for EIA in the UK The Environmental Impact Assessment (EIA) Directive 2014/52/EU (amending Directives 2011/92/EU and 85/337/EEC sets out the requirements for EIA and defines in Annex I and Annex II the types of projects where a statutory EIA is mandatory or at the discretion of Member States respectively. The Marine Works (Environmental Impact Assessment) Regulations 2007 (as amended) (the EIA Regulations) and Schedule A1 and A2 of these regulations, transpose the EIA Directive and the two annexes into UK law. The installation of cables or cable protection is not listed on Schedule A1 or A2 of the EIA Regulations therefore a statutory EIA is not required for the marine aspects of the project in English inshore and offshore waters.
Gridlink recognises that they will be required to provide environmental supporting information in support of their Marine License application. In addition, as an interconnector license holder, Gridlink has a duty to preserve amenity. Gridlink is committed to completing appropriate marine surveys, assessments of potential environmental effects and stakeholder consultations to fulfil this duty. Gridlink consider it best practice to meet its obligations by undertaking a non-statutory Environmental Appraisal (EA). Whilst not a statutory EIA, the EA will be undertaken in accordance with relevant best practice. An Environmental Report will be prepared to accompany the Marine Licence application to the MMO. This will report on the environmental appraisal process, its findings and conclusions for the marine components of the project, and also set out proposed mitigation measures to avoid or reduce the level of any possible impacts to an acceptable level. 3.3 Need for EIA in France The elements of GridLink within France are subject to a mandatory requirement for an EIA according to the Code de l’environnement, where an EIA is required for the “construction of an underground cable longer than 15 km and a voltage higher than 225 kV”. The onshore HVDC cable route is approximately 13 km long and the subsea cable route is approximately 32 km from the French coast to the UK-France median line. The cable rating will be 525 kV. Therefore, for the French section of the project. a mandatory EIA is required for the onshore/ offshore cable and also the converter station in order for the entire project to be assessed as a whole.
21 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
4. SCOPING METHODOLOGY 4.1 Introduction The Guidance on EIA (European Commission, 2001) states that scoping is: “the process of determining the content and extent of the matters which should be covered in the environmental information to be submitted to a competent authority for projects which are subject to EIA”. Schedule 4 of the Marine EIA Regulations sets out the procedure for obtaining a Scoping Opinion. It states that: “A request for a scoping opinion must be accompanied by: (a) a chart, plan or map sufficient to identify the location of the regulated activity and of other activities to be carried out in the course of the project; (b) a brief description of the specific characteristics of the regulated activity and the project, including their nature, purpose, location and technical capacity; (c) an explanation of the likely significant effects of the regulated activity and the project on the environment; and (d) such other information or representations as the Applicant may wish to provide or make.” This Scoping report has been prepared in accordance with the guidelines set out in Schedule 4 of the Marine EIA Regulations to seek the opinion of the MMO as competent authority regarding the proposed approach for the non-statutory Environmental Appraisal of the Proposed Development. 4.2 Scoping Methodology Desk-based, publicly available information regarding the baseline environmental topics has been collated to inform the scoping assessment. An assessment of significance of each potential pressure1 resulting from the Proposed Development has been undertaken to decide which of the pressures could potentially be significant and therefore should be taken forward to be assessed and reported in the EA. Those which are deemed to be non- significant are scoped out of the EA and no further assessment will be undertaken. The pressures which are covered in this scoping report are provided in Table 4-1 below. On advice from the Joint Nature Conservation Committee (JNCC), descriptions of pressures for the physical/chemical and biological environment have been taken from the Intersessional Correspondence Group (ICG) pressure list (JNCC 2011). The ICG pressure list does not include human pressures, and therefore, categories have been developed based on industry experience. The pressures relevant to marine cable installation, operation and maintenance have been selected from the list and presented in Table 4-1.
1 A pressure can be defined as “the mechanism through which an activity has an effect on any part of the ecosystem”. The nature of the pressure is determined by activity type, intensity and distribution. A list of marine pressures and their definitions has been formally agreed by the OSPAR Intercessional Correspondence Group on Cumulative Effects (ICG-C).
22 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Table 4-1 Pressure Description
Baseline sections
Pressure description
Physical environment Benthic ecology Marine mammals and Marine birds coastal Fisheries Marine archaeology
Water flow (tidal current) changes – local Wave exposure changes – local (i.e. changes to wave pattern from rock berms) Penetration and/or disturbance of the substrate below the surface of the seabed, including abrasion (change to seabed features) Transition elements and organo-metal contamination Temperature changes – local Physical change (to another seabed type) Changes in suspended solids (water clarity) Siltation rate changes, including smothering (depth of vertical sediment overburden) Electromagnetic changes Underwater noise changes Visual disturbance Displacement Snagging hazard Direct damage to archaeological asset, submerged prehistory and/or palaeolandscapes Indirect damage to archaeological asset
Three pressures are not included in this scoping assessment for the following reasons.
1. Death or injury by collision - Although shipping collision is a recognised cause of marine mammal mortality worldwide, the key factor influencing the injury or mortality caused by collisions is ship size and speed. Ships travelling at 14 knots or faster are most likely to cause lethal or serious injuries. Although the presence of the cable lay vessels and support vessels will marginally increase the level of vessel activity within the area for the duration of the marine works, none of the project vessels will be travelling at speeds exceeding 14 knots. Cable lay vessels move along the cable route at the rate of cable installation, approximately 200-400 m per hour depending on sediment conditions, resulting in a low likelihood of collision. Given that vessels will be operating at less than 14 knots, the pressure is not considered further.
23 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
2. Hydrocarbon and PAH contamination - Unplanned events (accidental oil or chemical spills) have been scoped out of the scoping assessment for the following reasons: ▪ The likelihood of a large oil spill occurring from a Project vessel is extremely low and the risk is no greater than that for any other vessel in the Project area. ▪ All Project vessels will have control measures and shipboard oil pollution emergency plans (SOPEP) in place and will adhere to MARPOL Annex I requirements. ▪ A Construction Environmental Management Plan (CEMP) and an Emergency Spill Response Plan will be developed and implemented for the installation phase. 3. Introduction or spread of non-indigenous species - The introduction of invasive non-native species (e.g. through discharge of ballast water from project vessels) will be managed under the International Convention for the Control and Management of Ship’s Ballast Water and Sediments. The project will complete a biosecurity risk assessment. This would include factors such as origins of the vessels and ensuring that relevant equipment is cleaned before use. The potential significance of an interaction between a receptor and a pressure has been assessed in terms of the relationship between two factors: 1. The magnitude of the potential pressure (direct or indirect), including consideration of duration and reversibility; and 2. The importance of the receptor (identified through the description of the baseline environment) in terms of its importance, adaptability, recoverability and sensitivity. Where mitigation measures that seek to avoid, reduce or compensate for significant effects on the environment are embedded in the design of the Proposed Development, these are described and considered as part of the assessment of significance to determine inclusion within the scope of the EA. 4.3 Consultation Consultations have been undertaken to discuss and agree the contents of this Scoping Report. Table 4-2 details the consultations that have been undertaken to date. Table 4-2 Consultations Undertaken to Date
Consultee Date Purpose of Consultation
Medway Council January 2017 GridLink progress update and ongoing consultation on development consent requirements Marine Management Organisation January 2017 GridLink progress update and ongoing consultation on development consent requirements Medway Council February 2017 Stakeholder Workshop Marine Management Organisation Historic England Kent County Council Archaeology Environment Agency Natural England March 2017 Stakeholder Workshop Kent County Council Ecology Natural England May 2018 Stakeholder Workshop
24 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Consultee Date Purpose of Consultation
Joint Nature Conservation Committee
In addition, relevant land-owners along the Medway Estuary have also been consulted regarding the Proposed Development and specifically the location of the converter station and cable route, including: ▪ Crown Estate; ▪ Port of London Authority; ▪ Peel Ports; ▪ London Thamesport; ▪ Goodmans Logistics; ▪ Scottish Power; ▪ Uniper (formerly E.on). Consultations will continue with the competent authorities, statutory and non-statutory stakeholders during the EA studies and preparation of the Environmental Report.
25 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
5. SEABED SEDIMENTS AND PHYSICAL PROCESSES 5.1 Introduction This chapter describes the seabed sediments and physical processes of the Medway Estuary, Thames Estuary and the southern North Sea. It provides the rationale for excluding certain interactions from further consideration; and for those which are to be considered further, it explains the appraisal of the effects of the offshore elements of the Proposed Development on those aspects of the seabed sediments and physical processes. 5.2 Baseline Conditions The Medway Estuary is part of a coastal system that extends from Harwich to North Foreland and is characterised by eroding cliffs, mud and sand flats and estuary and island units. This area has been strongly influenced by the Thames Estuary throughout the Holocene. The geology of the shoreline and sub-tidal zone is comprised of London Clay overlain in places by glacial drift sediments. The position of the Medway Estuary is largely dictated by the position of outcrops of London Clay2. The underlying geology of the outer Thames Estuary is predominantly comprised of Tertiary London Clay Formation overlain by Quaternary sediments of Pleistocene and Holocene, including sands, gravels, silts, clays and peats. The seabed in the Thames Estuary is characterised by numerous sandbanks. The southern North Sea is a shallow shelf that is dominated by a deep channel to the west, connected to the Straits of Dover, flowing into the English Channel. Holocene sediments are generally present as a thin veneer of mainly sand and gravel, which cover older sediments. Sand ribbons, sandbanks and sand waves are a common feature of the southern North Sea, although the water is shallow enough for wave induced currents with sufficient strength to move bottom sediments these are considered to be of minor importance compared to the stronger influence of the tidal currents. The offshore sandbanks are thought to have formed relatively early in the Holocene period as the sea transgressed through the Dover Straight. Sandy sediments (sandy gravels, sand and gravelly sands) dominate over much of the offshore area and much of this sand is mobile.
5.2.1 Bathymetry The proposed cable route passes through the Medway Estuary, the Thames Estuary and into the southern North Sea before crossing the median line and passing into French territorial waters. Away from the coast, the seabed channel area features relief at water depths varying between 20 m and 55 m. The slopes are generally less than 1 degree and occasionally exceed 5 degrees. The water depth increases to 55 m from 15 km from the coast, with slopes varying between 3 and 6 degrees.
5.2.2 Tides The Medway Estuary is a macro tidal estuary with a spring tidal range of 5.2 m at Sheerness decreasing to 5.1 m at Rochester. Variations in the dimensions of the sub-tidal and intertidal areas in the Medway Estuary result in variations in the propagation of the tidal wave through the Estuary. In the outer and inner areas of the Estuary, the ebb tide is dominant with a shorter duration and higher
2 Halcrow Group Limited. 2010. Medway Estuary and Swale Shoreline Management Plan. Appendix C: Baseline Process Understanding
26 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
velocity, whereas in the middle, the flood tide is more dominant. In the southern North Sea, the tidal wave propagates southwards and is amplified by shallow water effects in the Thames Estuary2. Short term fluctuations in mean sea level (MSL) are often associated with storm surges and seasonal variations, relating to temperature, pressure and wind regimes. The tidal asymmetry affects the tidal flows recorded in the Medway Estuary. In the outer channel, peak ebb velocities reach 0.9 m/s, while flood velocities reach 0.4 m/s. In the middle section, maximum flood tidal velocities of 0.95 m/s and ebb velocities of 0.55 m/s are recorded, whereas within the inner channel velocities of 0.6 m/s and 0.4 m/s were recorded for ebb and flood tidal flows respectively3. The Thames Estuary is also macro-tidal with a tidal range that increases from 5.2 m at Sheerness to 6.6 m in central London as a result of a funnelling effect of the estuary. Tidal currents within the outer Thames Estuary have been recorded up to approximately 1.47 m/s4. Within this area of the southern North Sea, the tidal range is approximately 4.8 m on spring tides and 2.7 m on neap tides. Peak current velocities reach between 1 m/s and 1.5 m/s3.
5.2.3 Waves The Medway Estuary is relatively protected from North Sea waves due to the configuration of sandbanks and the narrow mouth of the estuary. The wave climate within the Medway Estuary is therefore dominated by internally generated wind waves. It is reported that wave heights in the Medway Estuary are usually less than 1 m in height and extreme waves do not exceed 2 m2. The outer Thames Estuary is influenced by both estuarine and open coast processes and is characterised by a relatively mild wave climate. Waves are predominantly influenced by winds from the southwest and the northeast. Significant wave heights are less than 1 m throughout the year, with the highest recorded in winter at 1.17 m3.
5.2.4 Sediment Transport It is estimated that, at any one time, 25,000 m3 of material is suspended within the tidal prism of the Medway Estuary. The most significant source of sediment is the offshore supply of suspended sediment from the Greater Thames Embayment. Potential supplies also include relict sediments contained within saltmarshes, alluvium derived from erosion of chalk and sandstone hills by the Medway River and sediment contained within the London Clay cliffs located along the northern coast of the Isle of Sheppey2. The currents and movement of sediments in the outer Thames Estuary are dominated by tidal flow. The sediment mobility indicators include sand streaks and ribbons, mega ripples and sand waves. Sandbanks are dominant features with the pattern of sand movement around each bank being generally clockwise. Bedforms are often absent in the troughs and interbank areas. The clockwise circulation tends to bring sand into the inner reaches of the estuary and to the more mobile sandbanks5. The presence of sandbanks generates complex sediment transport pathways in certain areas. Sandbanks located off the north Kent coast are believed to influence sediment transport patterns, and sand from these banks feed onshore, replenishing the sand beaches along the Thanet coast, as
3 Institute of Estuarine and Coastal Processes (ICES).1993. The Medway Estuary. Coastal Processes and Conservation. University of Hull. June 1993 4 Department for Business, Enterprise and Regulatory Reform. 2008. Atlas of UK Marine Renewable Energy Resources. Available from: http://www.renewables-atlas.info/ (accessed 08/03/2017) 5 HR Wallingford; CEFAS/UEA; Posford Haskoning, D’Olier, B. 2002. Southern North Sea Sediment Transport Study Phase 2. Sediment Transport Report. Report EX4526. August 2002
27 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
shown in Figure 5-1. Sediment transport along the eastern UK coast is generally northwards, but is directed southwards through the deeper water of the Straits of Dover6. Schematic Sediment Transport Pathways5
5.3 Mitigation Measures Following the results of the offshore bathymetric, geophysical, geotechnical and environmental surveys, the cable will be micro-routed within the survey corridor to avoid areas of seabed features such as sand waves and sand banks wherever possible. If avoidance is not possible, then the distance through which the cable route interacts with these seabed features will be minimised. The cable will be buried, with the burial depth dependent on the results of a burial risk assessment. Sediment will be back filled into the trench following installation of the cable although natural hydrodynamic processes are likely to bury the cable relatively quickly. The extent of the cable route requiring external protection, i.e. by rock placement or concrete mattressing is limited to only where the cable crosses existing third party infrastructure or where seabed conditions inhibit cable burial or increase risk of cable exposure, e.g. by scour effects. The cable lay vessel will utilise dynamic positioning wherever possible, minimising the interaction between the vessel and the seabed due to anchoring. 5.4 Potential Effects to be Excluded from the EA The potential effects on seabed sediments and physical processes that are proposed to be excluded from the EA are defined in Table 5-1.
6 Project Management Support Services Ltd. 2013. NemoLink Environmental Statement Volume I. February 2013
28 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Table 5-1 Effects on Seabed Sediments and Physical Processes to be Excluded from the EA
Potential Effect Phase of Project Rationale for Exclusion
Penetration and/or Construction The ploughing of the seabed associated with cable installation disturbance of the will result in the disturbance of seabed sediments from the substrate below the trench to an area of seabed either side. The material displaced surface of the will then be back filled into the trench following installation of seabed, including the cable. Any changes to the seabed, sediment transport or abrasion (change to hydrodynamics will be temporary in nature during the seabed features) construction phase and natural processes are expected to return the seabed to pre-construction conditions in a short period of time. Note: Effects on the benthic environment are considered separately in this report. Vessels operating within shallow water, e.g the Medway Estuary, are likely to be anchored during cable installation. However, the footprint of the seabed affected by the anchoring is considered to be small and temporary in nature. Further offshore, vessels will utilise dynamic positioning ensuring that there is no interaction with the seabed and therefore no effects are expected. Water flow (tidal Operation Where cables cannot be routed around outcropping bedrock or current) changes - where third-party infrastructure is required to be crossed, local external protection will be used to protect the cable. The requirement for this external protection will be limited as much as possible. Any change in bathymetry as a result of external protection is considered to be insignificant due to the localised application of external protection. Any changes to water flows as a result in local changes to bathymetry are not expected to be noticeable above natural variation. Note: Effects on the reduction of navigable depth and changes to the benthic environment are considered separately in this report.
5.5 Potential Effects to be Included in the EA The potential effects on seabed sediments and physical processes that are proposed to be included in the EA are summarised in Table 5-2. Table 5-2 Effects on Seabed Sediments and Physical Processes to be Included in the EA
Potential Effect Phase of Project Rationale for Inclusion
Wave exposure Construction Where the desired cable trenching depth cannot be achieved, changes – local (i.e. external protection will be used to protect the cable. This will changes to wave include the use of concrete mattresses or rock placement. This pattern from rock may result in localised effects on bathymetry, hydrodynamics berms) and sediment transport. The seabed along the cable route is predominantly sandy mixed sediments, hence potential exists for localised scour down current of any external protection.
29 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
5.6 Additional Baseline Information and Collection Methods Bathymetric, geophysical, geotechnical and environmental surveys will be undertaken along the proposed cable route. The surveys will utilise a range of standard data collection techniques including side-scan sonar, multi-beam echo sounder, sub-bottom profiler, magnetometer, vibrocore, cone penetration tests, grab sampling and video/still photography surveys. Information on the seabed sediment particle size data will be derived from both the geotechnical and environmental surveys. The results of the bathymetric, geophysical, geotechnical and environmental surveys, together with a baseline desk study, will provide information on the following: a. Seabed sediment composition and distribution and variability of sediment thicknesses; b. Shallow sub-seabed conditions; c. Sediment transport pathways; d. Existing coastline and shoreline dynamics, including long term seabed and shoreline stability; e. Scour around adjacent cables and pipelines; f. Natural seabed obstructions and features; g. Man-made seabed obstructions and features; h. Bathymetric setting; i. Oceanographic setting; j. Seasonal variations in climate and weather; k. Typical sea states; l. Seabed currents; and m. Wind and wave data. This information will be provided in the EA. 5.7 Appraisal of Potential Effects The EA will include an assessment of the effect on the seabed sediments and physical processes for those areas of the seabed along the proposed cable route where external protection is likely to be required. Effects will be determined based on a qualitative appraisal, taking into account the scale and extent of the potential effect. Where relevant, the determination of significance will be based on expert judgement, taking into account factors such as sensitivity and vulnerability of receptors, duration of the activity being considered that gives rise to the effect, and the permanence of the effect and recoverability of the receptor. Measures to mitigate potentially significant effects will be proposed as appropriate.
30 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
6. PROTECTED SITES FOR NATURE CONSERVATION 6.1 Introduction This chapter describes the protected sites for nature conservation of the Medway Estuary, Thames Estuary and the southern North Sea. It provides the rationale for excluding certain interactions from further consideration; and for those which are to be considered further, it explains the appraisal of the effects of the offshore elements of the Proposed Development on those aspects of the seabed sediments and physical processes. 6.2 Protected Sites for Nature Conservation
6.2.1 Natura 2000 Sites EC Council Directive 92/43/EC on the conservation of natural habitats and of wild fauna and flora (known as the ‘Habitats Directive’) and EC Council Directive 2009/147/EC on the conservation of wild birds (known as the ‘Birds Directive’) require European Union member states to work together within the same legislative framework to protect Europe’s most valuable species and habitats, irrespective of political or administrative boundaries. At the heart of these Directives is the creation of a network of Europe’s most valuable species and habitat sites, known as Natura 2000 sites. The aim of the Natura 2000 network is to ensure the long-term survival of European threatened species and habitats. The network comprises Special Areas of Conservation (SACs) designated under the Habitats Directive, and Special Protection Areas (SPAs) designated under the Birds Directive. SPAs and SACs are designated by individual member states. In addition, UK Government policy (ODPM Circular 06/2005) states that sites designated under the Convention on Wetlands (Ramsar, Iran 1971) known as the "Ramsar Convention" are also included under the definition Natura 2000 (known as ‘Ramsar sites’). The Ramsar Convention is an intergovernmental treaty that embodies the commitments of its member countries to maintain the ecological character of their Wetlands of International Importance and to plan for the "wise use", or sustainable use, of all of the wetlands in their territories” (RAMSAR 2011). The vast majority of Ramsar sites are also classified as SPAs. The subsea cable route crosses the Medway Estuary, Thames Estuary and southern North Sea, where the cable route crosses the Natura 2000 sites below: ▪ Medway Estuary and Marshes Special Protection Area (SPA) and wetland of international importance designated under the Ramsar Convention (RAMSAR) site; ▪ Outer Thames Estuary SPA; ▪ Margate and Long Sands Special Area of Conservation (SAC); ▪ Southern North Sea candidate Special Area of Conservation (cSAC). In addition, the cable route crosses the Banc des Flancres SPA and Special Conservation Interest (SCI) sites in French territorial waters. The Natura 2000 sites relevant to the Proposed Development are listed in Table 6-1.
31 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Table 6-1 Natura 2000 sites crossed or within 10 km of the Proposed Development
Distance from GridLink Project Site Designation Qualifying Features for Site Designation South of BritNed North of BritNed base case alternative Medway SPA Qualifies under Article 4.1 and 4.2 of the Birds Directive: Site crossed by offshore Site crossed by offshore Estuary and Article 4.1 - Breeding Season: Avocet (Recurvirostra avosetta); and Little tern (Sterna HVDC cable by Horizontal HVDC cable by Horizontal Marshes albifrons). Directional Drilling Directional Drilling Article 4.1 - Over Winter: Avocet (Recurvirostra avosetta) (200 m) (200 m) Article 4.2 - On passage: Ringed plover (Charadrius hiaticula). Article 4.2 - Over winter: Black-tailed godwit (Limosa limosa islandica); Dark-bellied Brent goose (Branta bernicla bernicla); Dunlin (Calidris alpina alpine); Grey plover (Pluvialis squatarola); Northern pintail (Anas acuta); Redshank (Tringa tetanus); Ringed plover (Charadrius hiaticula); Shelduck (Tadorna tadorna). Also qualifies under Article 4.2 by regularly supporting at least 20,000 waterfowl. Medway Ramsar Ramsar Criterion 2: The site supports 10 nationally scarce plants and 14 British Red Site crossed by offshore Site crossed by offshore Estuary and Data Book invertebrates. HVDC cable by Horizontal HVDC cable by Horizontal Marshes Directional Drilling Directional Drilling Ramsar Criterion 5: Assemblages of international importance species with peak (200 m) (200 m) counts in winter of 47,637 waterfowl (five- year peak mean 1998/1999 to 2002/2003). Ramsar Criterion 6: Species/ populations occurring at levels of international importance: Peak Counts in Spring/Autumn - Grey plover (Pluvialis squatarola); Common redshank (Tringa totanus totanus). Peak Counts in Winter - Dark-bellied Brent goose (Branta bernicla bernicla); Common shelduck (Tadorna tadorna), Northern pintail (Anas acuta); Ringed plover (Charadrius hiaticula); Red knot (Calidris canutus islandica); Dunlin (Calidris alpina alpina) Outer SPA Qualifies under Article 4.2: Site crossed by offshore Site crossed by offshore Thames - Red-throated diver (Gavia stellata), Common tern (Sterna hirundo); Little tern HVDC cable HVDC cable Estuary (Sternula albifrons) (49 km) (50 km) Margate and SAC Qualifying features listed within Annex 1 habitats: Site crossed by offshore Site crossed by offshore Long Sands - Sandbanks which are slightly covered by sea water all the time HVDC cable HVDC cable (21 km) (22 km)
32 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Distance from GridLink Project Site Designation Qualifying Features for Site Designation South of BritNed North of BritNed base case alternative Southern cSAC Qualifying Annex ll species: Site crossed by offshore Site crossed by offshore North Sea Harbour porpoise (Phocoena phocoena) HVDC cable HVDC cable (21 km) (21 km) Thames SPA Qualifies under Article 4.1 and 4.2 of the Birds Directive: 200 m 200 m Estuary and Article 4.1 - Over winter: Avocet (Recurvirostra avosetta); Hen harrier (Circus Marshes cyaneus). Article 4.2 - On passage: Ringed plover (Charadrius hiaticula) Article 4.2 - Over winter: Ringed plover (Charadrius hiaticula) Also qualifies under Article 4.2 by regularly supporting at least 20,000 waterfowl. Thames Ramsar Ramsar Criterion 2: The site supports 14 nationally scarce plants and wetland habitat 200 m 200 m Estuary and and 20 British Red Data Book invertebrates. Marshes Ramsar Criterion 5: Assemblages of international importance – species with peak counts in winter of 45,118 waterfowl (five-year peak mean 1998/99- 2002/2003). Ramsar Criterion 6: Species/ populations occurring at levels of international importance: Peak Counts in Spring/Autumn - Ringed plover (Charadrius hiaticula); Black-tailed godwit (Limosa limosa islandica). Peak Counts in Winter - Grey plover (Pluvialis squatarola); Red knot (Calidris canutus islandica); Dunlin (Calidris alpina alpine); Common redshank (Tringa tetanus) Benfleet and SPA Qualifies under Article 4.2 of the Birds Directive: 3 km 2 km Southend Article 4.2 - On passage: Ringed plover (Charadrius hiaticula). Marshes Article 4.2 - Over winter: Black-tailed godwit (Limosa limosa islandica); Grey plover (Pluvialis squatarola); Knot (Calidris canutus). Also qualifies under Article 4.2 by regularly supporting at least 20,000 waterfowl
33 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Distance from GridLink Project Site Designation Qualifying Features for Site Designation South of BritNed North of BritNed base case alternative Benfleet and Ramsar Ramsar Criterion 5: Assemblages of -international importance – species with peak 3 km 2 km Southend counts in winter of 32,867 waterfowl (five-year peak mean 1998/1999-2002/2003). Marshes Ramsar Criterion 6: Species/ populations occurring at levels of international importance: Peak Counts in Spring/Autumn - Dark-bellied Brent goose (Branta bernicla bernicla). Peak Counts in Winter - Grey plover (Pluvialis squatarola); Red knot (Calidris canutus islandica). Species Identified Subsequent to Designation for Possible Future Consideration under Criterion 6: Peak Counts in Winter - Dunlin (Calidris alpina alpina) Essex SAC Qualifying Annex I habitats: 3 km 2 km Estuaries - Atlantic salt meadows (Glauco-Puccinellietalia maritimae) - Estuaries - Mediterranean and thermos-Atlantic halophilous scrubs (Sarcocornetea fruticosi) - Mudflats and sandflats not covered by seawater at low tide - Salcornia and other annuals colonising mud and sand - Sandbanks which are slightly covered by sea water all the time Qualifying Annex II species: - Spartina swards (Spartinion maritimae)
34 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Distance from GridLink Project Site Designation Qualifying Features for Site Designation South of BritNed North of BritNed base case alternative Foulness SPA Qualifies under Article 4.1 and 4.2 of the Birds Directive: 3 km 2 km (mid-Essex Article 4.1 - Breeding Season: Avocet (Recurvirostra avosetta); Common Coast Phase tern (Sterna hirundo); Little tern (Sterna albifrons); Sandwich tern 5) (Sterna sandvicensis). Article 4.1 - Over Winter: Avocet (Recurvirostra avosetta); Bar-tailed godwit (Limosa lapponica); Golden plover (Pluvialis apricaria); Hen harrier (Circus cyaneus). Article 4.2 - On passage: Redshank (Tringa totanus). Article 4.2 - Over winter: Dark-bellied Brent goose (Branta bernicla bernicla); Grey plover (Pluvialis squatarola); Knot (Calidris canutus); Oystercatcher (Haematopus ostralegus). Also qualifies under Article 4.2 of the Directive (79/409/EEC) by regularly supporting at least 20,000 waterfowl Foulness Ramsar Ramsar Criterion 1: This site qualifies by virtue of the extent and diversity of 3 km 2 km (mid-Essex saltmarsh habitat present. This and four other sites in the mid-Essex Coast Ramsar Coast Phase Site complex, include a total of 3,237 ha, which represent 5) 70% of the saltmarsh habitat in Essex and 7% of the total area of saltmarsh in Britain. Ramsar Criterion 2: The site supports 21 nationally important plant species and 12 nationally important invertebrate species. Ramsar Criterion 3: The site contains extensive saltmarsh habitat, with areas supporting full and representative sequences of saltmarsh plant communities covering the range of variation in Britain. Ramsar Criterion 5: Assemblages of international importance – species with peak counts in winter of 82,148 waterfowl (five-year peak mean 1998/99-2002/2003). Ramsar Criterion 6: Species/ populations occurring at levels of international importance include: Peak Counts in Spring/Autumn - Common redshank (Tringa totanus totanus). Peak Counts in Winter - Dark-bellied Brent goose (Branta bernicla bernicla); Eurasian oystercatcher (Haematopus ostralegus ostralegus); Grey plover (Pluvialis squatarola); Red knot (Calidris canutus islandica); Bar-tailed godwit (Limosa lapponica)
35 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Distance from GridLink Project Site Designation Qualifying Features for Site Designation South of BritNed North of BritNed base case alternative Thanet Coast SAC Qualifying Annex 1 Habitats: 3 km 3 km - Reefs - Submerged or partially submerged sea caves The Swale SPA Qualifies under Article 4.1 and 4.2 of the Birds Directive: 9 km 10 km Article 4.1 - Breeding Season: Avocet (Recurvirostra avosetta); Marsh harrier (Sterna albifrons); Mediterranean gull (Larus melanocephalus). Article 4.1 - Over Winter: Avocet (Recurvirostra avosetta); Bar-tailed godwit (Limosa lapponica); Golden plover (Pluvialis apricaria); Hen harrier (Circus cyaneus). Article 4.2 - On passage: Ringed plover (Charadrius hiaticula). Article 4.2 - Over winter: Black-tailed godwit (Limosa limosa islandic); Grey plover (Pluvialis squatarola); Pintail (Anas acu); Knot (Calidris canutus); Redshank (Tringa tetanu); Shoveler (Anas clypea). Also qualifies under Article 4.2 by regularly supporting at least 20,000 waterfowl The Swale Ramsar Ramsar Criterion 2: The site supports nationally scarce plant species and seven 9 km 10 km nationally important invertebrate species. Ramsar Criterion 5: Assemblages of international importance – species with peak counts in winter of 77,501 waterfowl (five-year peak mean 1998/99-2002/2003). Ramsar Criterion 6: Species/populations occurring at levels of international importance: Peak Counts in Spring/Autumn - Common redshank (Tringa totanus totanus). Peak Counts in Winter - Dark-bellied Brent goose (Branta bernicla bernicla); Grey plover (Pluvialis squatarola). Species Identified Subsequent to Designation for Possible Future Consideration under Criterion 6: Peak Counts in Spring/Autumn - Ringed Plover (Charadrius hiaticula). Peak Counts in Winter - Black-tailed godwit (Limosa limosa islandica); Eurasian wigeon (Anas penelope); Northern pintail (Anas acuta); Northern shoveler (Anas clypeata)
36 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Distance from GridLink Project Site Designation Qualifying Features for Site Designation South of BritNed North of BritNed base case alternative Thanet Coast SPA Qualifies under Article 4.2 of the Birds Directive: 15 km 15 km and Sandwich Article 4.2 - Over winter: Turnstone (Arenaria interpres) Bay Thanet Coast Ramsar Ramsar Criterion 2: Supports 15 British Red Data Book wetland invertebrates 19 km 19 km and Sandwich Ramsar Criterion 6: Species/ populations occurring at levels of international Bay importance include: Peak Counts in Winter – Ruddy turnstone (Arenaria interpres interpres) Dungeness, SPA Qualifies under Article 4.1 and 4.2 of the Birds Directive: 46 km 46 km Romney Article 4.1 - Over winter: Bewick’s swan (Cygnus columbianus bewickii); Bittern Marsh and (Botaurus stellaris); Hen harrier (Circus cyaneus); Golden plover (Pluvialis apricaria); Rye Bay Ruff (Philomachus pugnax) Article 4.1 - On passage: Aquatic warbler (Acrocephalus paludicola) Article 4.1 - Breeding: Marsh harrier (Circus aeruginosus); Avocet (Recurvirostra avosetta); Mediterranean gull (Larus melanocephalus); Sandwich tern (Sterna sandvicensis); Common tern (Sterna hirundo); Little tern (Sterna albifrons). Article 4.2 - Over wintering: Shoveler (Anas clypeata) Also qualifies under Article 4.2 by regularly supporting at least 20,000 waterfowl Bancs de SPA Qualifies under Article 4 of the Birds Directive: Site crossed by offshore Site crossed by offshore Flandres - Red throated loon (Gavia stellata); Leach's storm petrel (Oceanodroma leucorhoa); HVDC cable HVDC cable (France) Mediterranian gull (Larus melanocephalus); Little gull (Larus minutus); Sandwich tern (31 km) (31 km) (Sterna sandvicensis); Common tern (Sterna hirundo); Arctic tern (Sterna paradisaea); Little tern (Sterna albifrons); Black tern (Chlidonias niger) Bancs de SCI Qualifying habitats: Site crossed by offshore Site crossed by offshore Flandres - Habitat type 1110: Sandbanks which are slightly covered by sea water all the time HVDC cable HVDC cable (France) Priority habitat sub-types present on the site: (31 km) (31 km) - 1110-2 Sand dunes (Atlantic coast) (Sables moyens dunaires (façade atlantique)) - 1110-4 Poorly sorted sands (Atlantic coast) (Sables mal triés (façade atlantique))
37 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Distance from GridLink Project Site Designation Qualifying Features for Site Designation South of BritNed North of BritNed base case alternative Platier d’Oye SPA Qualifying under Article 4 of the Birds Directive: 9 km 9 km (France) - Red throated loon (Gavia stellata); Eurasian bittern (Botaurus stellaris); Great egret (Egretta alba); Purple heron (Ardea purpurea); Black stork (Ciconia nigra); White stork (Ciconia ciconia); Eurasian spoonbill (Platalea leucorodia); Berwick's swan (Cygnus columbianus bewickii ); Barnacle goose (Branta leucopsis); Smew (Mergus albellus); European honey buzzard (Pernis apivorus); Black kite (Milvus migrans); White-tailed eagle (Haliaeetus albicilla); Western marsh harrier (Circus aeruginosus); Hen harrier (Circus cyaneus); Seahawk (Pandion haliaetus); Merlin (Falco columbarius); Peregrine falcon (Falco peregrinus); Common crane (Grus grus); Black winged stilt (Himantopus himantopus); Pied avocet (Recurvirostra avosetta); Kentish plover (Charadrius alexandrinus); European golden plover (Pluvialis apricaria); Ruff (Philomachus pugnax); Bar tailed godwit (Limosa lapponica); Wood sandpiper (Tringa glareola); Terek sandpiper (Xenus cinereus); Red-necked phalarope (Phalaropus lobatus); Mediterranean gull (Larus melanocephalus); Sandwich tern (Sterna sandvicensis); Common tern (Sterna hirundo); Arctic tern (Sterna paradisaea); Little tern (Sterna albifrons); Whiskered tern (Chlidonias hybridus); Black tern (Chlidonias niger); Common kingfisher (Alcedo atthis); and Woodlark (Lullula arborea) Acronyms:
SAC – Special Area of Conservation designated under Council Directive 92/43/EC (known as the “Habitats Directive”) for specific habitats listed on Annex I and for species listed on Annex II SCI – Site of Community Importance designated under Council Directive 92/43/EC (known as the “Habitats Directive”) for specific habitats listed on Annex I and for species listed on Annex II adopted by the EC but not formally designated by the Member State government SPA – Special Protection Area designated under Council Directive 2009/14/EC (known as the “Birds Directive”) for rare, threatened or vulnerable bird species listed in Article 4 of the Directive, and for regularly occurring migratory species Ramsar – sites designated under the Convention on Wetlands (known as the "Ramsar Convention") to protect wetlands of international importance.
38 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
6.2.2 National Designated Sites The UK Government designates sites for nature conservation as below: ▪ Marine Conservation Zone (MCZ) under Marine and Coastal Access Act 2009 as sites of nationally important marine wildlife, habitats, geology and geomorphology; in addition, prior to formal adoption, an area may be designated a Recommended Marine Conservation Zone (rMCZ) ▪ Site of Special Scientific Interest (SSSI) under the Wildlife and Countryside Act 1981 (as amended) as nationally important areas of land and water (above mean low water) The cable route crosses the national sites of nation conservation interest below: ▪ Medway Estuary and Marshes Site of Special Scientific Interest (SSSI); ▪ Medway Estuary Marine Conservation Zone (MCZ); ▪ Goodwin Sands recommended Marine Conservation Zone (rMCZ); ▪ Offshore Foreland rMCZ The national designated sites of nature conservation interest relevant to the Proposed Development are listed in Table 6-2.
39 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Table 6-2 NATURA 2000 sites crossed or within 10 km of the Proposed Development
Distance from GridLink project Site Designation Reason for Designation South of BritNed North of BritNed base case alternative Medway SSSI Reason for notification: Site crossed by offshore Site crossed by offshore Estuary and Large area of intertidal habitats representative of the estuarine habitats found on the HVDC cable by Horizontal HVDC cable by Horizontal Marshes North Kent coast Directional Drilling Directional Drilling (200 m) (200 m) Complex of mudflats and saltmarsh with grazing marsh intersected by dykes and fleets The site holds internationally important populations of wintering and passage birds, for example, shelduck (Tadorna tadorna), brent goose (Branta bernicla), grey plover (Pluvialis squatarola), ringed plover (Charadrius hiaticula), pintail (Anas acuta), dunlin (Calidris alpine), redshank (Tringa totanu) and is nationally important for breeding birds, for example, turnstone (Arenaria interpres), black-tailed godwit (Limosa limosa), curlew (Numenius arquata), great crested grebe (Podiceps cristatus), shoveler (Anas clypeata), teal (Anas crecca), wigeon (Anas Penelope) and white-fronted goose (Anser albifrons) An outstanding assemblage of plant species also occurs, including sea aster (Aster tripolium), sea lavender (Limonium vulgare), cord-grass (Spartina anglica) and saltmarsh-grass (Puccinellia maritima), and scarce species such as golden samphire (Inula crithmoides), perennial glasswort (Salicornia perenni) and oneflowered glasswort (Salicornia pusilla) Medway MCZ Qualifying features: Site crossed by offshore Site crossed by offshore Estuary - Intertidal mixed sediments; Intertidal sand and muddy sand; Subtidal coarse HVDC cable HVDC cable sediment; Subtidal mud; Subtidal sand; Low energy intertidal rock (12 km) (12 km) - Estuarine rocky habitats - Peat and clay exposures - Tentacled lagoon-worm (Alkmaria romijni) Goodwin rMCZ Qualifying features: Site crossed by offshore Site crossed by offshore Sands - Moderate energy infralittoral rock; Moderate energy circalittoral rock; Subtidal HVDC cable HVDC cable coarse sediment; Subtidal sand (10 km) (10 km) - Blue mussel (Mytilus edulis) beds - Ross worm (Sabellaria spinulosa) reefs - Eastern English Channel outburst flood features
40 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Distance from GridLink project Site Designation Reason for Designation South of BritNed North of BritNed base case alternative Offshore rMCZ Qualifying features: Site crossed by offshore Site crossed by offshore Foreland - High energy infralittoral rock; High energy circalittoral rock; Moderate energy HVDC cable HVDC cable circalittoral rock; Subtidal coarse sediment; Subtidal sand (4 km) (4 km) - Eastern English Channel outburst flood features The Swale MCZ Qualifying features: 1 km 1 km Estuary - Estuarine rocky habitats - Low energy intertidal rock South SSSI Reason for notification: 3 km 3 km Thames Extensive mosaic of grazing marsh, saltmarsh, mudflats andshingle characteristic of the Estuary and estuarine habitats of the north Kent marshes. Freshwater pools and some areas o f Marshes woodland provide additional variety and complement the estuarine habitats The site supports outstanding numbers of waterfowl with total counts regularly exceeding 20,000, and many species regularly occuring in nationally important numbers and some species regularly using the site in internationally important numbers. Breeding birds are also of particular interest The diverse habitats also support a number of nationally rare and scarce invertebrate species and an assemblage of nationally scarce plants Thanet MCZ Qualifying features: 3 km 3 km Coast - Subtidal coarse sediment; Subtidal mixed sediments; Subtidal sand; Moderate energy infralittoral rock; Moderate energy circalittoral rock - Blue mussel (Mytilus edulis) beds - Peat and clay exposures - Ross worm (Sabellaria spinulosa) reefs - Subtidal chalk - Stalked jellyfish (Haliclystus auricula) - Stalked jellyfish (Lucernariopsis cruxmelitensi)
41 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Distance from GridLink project Site Designation Reason for Designation South of BritNed North of BritNed base case alternative Thames rMCZ Qualifying features: 7 km 7 km Estuary - Intertidal sand/muddy sand; Intertidal mixed sediments; Subtidal coarse sediment; Subtidal sand; Subtidal mud; Sheltered muddy gravels - Tentacled lagoon worm (Alkmaria romijni) - European eel (Anguilla anguilla) - Smelt (Osmerus eperianus) Note: rMCZ has been split into two separate sites; Upper Thames important for smelt (Osmerus eperianus); and Swanscombe important for Tentacled lagoon worm (Alkmaria romijni) Acronyms: MCZ – Marine Conservation Zone under Marine and Coastal Access Act 2009 as sites of nationally important marine wildlife, habitats, geology and geomorphology rMCZ – Recommended Marine Conservation Zone under Marine and Coastal Access Act 2009 as sites of nationally important marine wildlife, habitats, geology and geomorphology SSSI – Site of Special Scientific Interest under the Wildlife and Countryside Act 1981 (as amended) as nationally important areas of land and water (above mean low water) NNR – National Nature Reserve LNR – Local Nature Reserve
42 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
6.3 Preliminary Consultations with Natural England and Joint Nature Conservation Committee The key issues raised during consultations to date (in terms of pressures exerted on protected sites and species) with Natural England in their Discretionary Advice Service (DAS) Letter (see Appendix A) and Natural England and JNCC at meeting on 15 May 2018 are summarised below. 1. Physical change to another seabed type: Rock placement at i) cable crossings and ii) in areas where seabed conditions prevent burial to the target depth. The placement of rock represents the introduction of a new substrate which has a long-term impact on the receiving environment. Figure 2-2 provides an indication of the cable crossing locations the proposed cable route crosses in relation to protected sites. The location of rock placement other than for crossings is not yet known and will be investigated further after a cable burial risk assessment has been undertaken following receipt of seabed survey results. However, due to the seabed geology comprising sediments with a general absence of hard rock that would inhibit burial, the need for additional rock placement is expected to be limited and not significant. 2. Penetration and / or disturbance of the substrate below the surface of the seabed, including abrasion: Cable installation activities which may damage sensitive habitats in protected sites designated for their habitats, in particular Margate and Long Sands SAC, such as Sabellaria reef and other protected / priority habitats. 3. Underwater sound changes: Disturbance from underwater noise on marine mammals and fish, including taking into consideration in-combination effects. 4. Visual disturbance: Visual and noise disturbance from the physical presence of vessels and equipment on sensitive species of birds, such as the red-throated diver. 5. Electromagnetic changes: Effects of EMF from the operation of the cables on marine life. The following text whilst not an exhaustive list of protected sites which will be considered in the HRA and MCZ assessments, highlights key concerns in relation to the proposed cable: Margate and Long Sands SAC: The proposed cable route has the potential to impact the biotope SS.SCS.ICS.SLan through pressures 1 and 2 above, which has variable sensitivity for S.spinulosa reef. Targeted sampling within this SAC within the survey corridor during the benthic survey is recommended to identify the presence of any S.spinulosa reef. Southern North Sea cSAC: The main concern is from possible in-combination effects of underwater noise (pressure 1) on harbour porpoise from noisy activities such as geophysical surveys and UXO detonation. Outer Thames Estuary SPA: There is potential for pressure 4 - visual and noise disturbance to adversely affect over wintering red-throated diver and breeding foraging tern species. Medway Estuary and Marshes SPA/Ramsar: There is potential for pressure 4 - visual and noise disturbance to adversely affect over wintering waterfowl. Goodwin Sands and Offshore Foreland rMCZs: The proposed cable route has the potential to impact rock habitats, sabellaria reef and mussel beds through pressures 1 and 2 above. 6.4 Appraisal of Potential Effects Protected sites and species will be characterised and assessed within the relevant chapters of the EA (Benthic Ecology, Marine and Coastal Birds, Marine Mammals and Fisheries).
43 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Additionally, a standalone Habitats Regulation Appraisal (HRA) and Marine Conservation Zone (MCZ) Assessment will be undertaken to provide an assessment of potential effects on protected sites and species. These will be appended to the EA. In recognition that it is useful to have all the information in one central place, a summary of the findings of these assessments will be presented in the EA. 6.5 Habitats Regulation Appraisal
6.5.1 The ‘Habitat Regulations’ Each EU Member State must implement the EU legislation in national law. In the UK, obligations under the Habitats and Birds Directives are transposed in the UK offshore area (broadly from the 12 nautical mile limit outwards) through The Offshore Marine Conservation (Natural Habitats, & c) Regulations 2017 (OMR), and in territorial waters (coastal waters up to 12 nautical miles) by The Conservation of Habitats and Species Regulations 2017. Collectively they are referred to as the ‘Habitats Regulations’. The Habitat Regulations transpose Article 6(3) of the Habitats Directive into UK law. This requires project-related activities within Natura 2000 sites to be assessed with regard to their implications for the site conservation objectives. Under regulation 28(3) of the OMR and regulation 63(2) of the Conservation of Habitats and Species Regulations 2017, a person applying for consent, permission or other authorisation must provide such information as the competent authority may reasonably require for the purposes of assessment or to enable them to determine whether an Appropriate Assessment (AA) is required. The three tests set out to determine if a proposal will affect a Natura site are: ▪ Is the proposal directly connected with or necessary for site management for nature conservation? ▪ Is the proposal likely to have a significant effect on the site either alone or in-combination with other plans or projects? (this is the Screening Stage); ▪ Can it be ascertained that the proposal will not adversely affect the integrity of the site? (this is the Appropriate Assessment stage). The tests are known as the Habitats Regulations Appraisal (HRA) process. Wherever a project that is not directly connected to, or necessary to, the management of a Natura 2000 site has the potential to have a significant effect on the conservation objectives of the site (directly, indirectly, alone or in-combination with other plans or projects) then an Appropriate Assessment (AA) must be undertaken by the competent authority. The EA will include a stand-alone HRA to inform the Appropriate Assessment for the Proposed Development. 6.6 Marine and Conservation Zone Assessment
6.6.1 Marine Conservation Zones Marine Conservation Zones (MCZs) are designated under the Marine and Coastal Access Act 2009 (MCAA) to protect a range of nationally important marine habitats, species and geological formations in English and Welsh territorial waters and UK offshore waters. In conjunction with other existing international and national designations, these sites contribute to an ecologically coherent network of Marine Protected Areas (MPA) in the North East Atlantic.
44 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
6.6.2 MCZ Assessment Process Section 126 of the MCAA places a regulatory duty on the Marine Management Organisation (MMO) to take into consideration MCZs during marine licence decision making. The assessment of a project’s effects upon any relevant MCZs or recommended Marine Conservation Zones (rMCZs) is necessary prior to the granting of a marine licence, demonstrating that potential environmental effects have been identified and if necessary, measures agreed between the Applicant and the regulator to reduce effects to an acceptable level. There are three stages to the MCZ assessment process: ▪ Screening ▪ Stage 1 assessment ▪ Stage 2 assessment These stages are described below.
6.6.2.1 Screening The first step is to determine whether the proposed project will take place within or near to any MCZs or rMCZs. The second step is to determine whether the activities of the proposed project are capable of affecting (other than insignificantly) either (i) the protected features of an MCZ; or (ii) any ecological or geomorphological process on which the conservation of any protected feature of an MCZ is (wholly or in part) dependent.
6.6.2.2 Stage 1 Assessment MCZs that are screened as being of relevance will be assessed within a Stage 1 Assessment. The Stage 1 Assessment determines whether: a. There is no significant risk of the activity hindering the achievement of the conservation objectives stated for the MCZ; and b. The MMO can exercise its functions to further the conservation objectives stated for the MCZ (The MMO has a responsibility to regulate proposed project activities to ensure the conservation objectives of a MCZ will not be compromised and can still be achieved if the activities go ahead). This stage includes consideration of relevant mitigation measures. If after considering mitigation measures the conditions of Section 126 cannot be met a Stage 2 Assessment is required.
6.6.2.3 Stage 2 Assessment This stage will determine whether the benefit to the public of proceeding with the project clearly outweighs the risk of damage to the environment; and if so, then whether, the Applicant can satisfy the MMO that they will undertake or make compensatory arrangements for measures of equivalent environmental benefit to the damage in or on the MCZ. The EA will include a stand-alone MCZ Assessment, including screening, Stage 1 and Stage 2 as appropriate, to inform the MMO regarding the potential impacts of the Proposed Development on MCZs.
45 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
7. BENTHIC ECOLOGY 7.1 Introduction This chapter describes the benthic environment, including habitats and species of conservation concern. It provides the rationale for excluding certain interactions from further consideration; and for those which are to be considered further, it explains the proposed approach to additional baseline characterisation and to the subsequent appraisal of the effects of the Proposed Development on those aspects of the benthic environment. 7.2 Baseline Conditions The intertidal habitats comprise a mosaic of mud and sandflats, saltmarsh, seagrass beds, shingle and coastal grazing marshes that support a wide range of bivalve and gastropod molluscs, polychaete and oligochaete worms. These habitats, especially saltmarsh and intertidal muds, are known to provide a wide range of ecosystem services including: ▪ Nutrient and carbon storage; ▪ Attenuating waves and tides acting as flood defence systems; ▪ Feeding and roosting grounds for birds; and ▪ Nursery and feeding grounds for ecologically and commercially important fish stocks. A large area of saltmarsh (Stoke Saltings) has developed in the Medway Estuary and is reported to be accreting7. This and other intertidal habitats of the Medway Estuary are of local, regional and national significance as a nursery area for a number of key commercial fish stocks8 and they are internationally designated Natura 2000 sites. The Medway Estuary is also recognised as one of only a few locations within the southeast where the tentacled lagoon worm (Alkmaria romijni) is known to occur9. This species is protected under Schedule 5 of the Wildlife and Countryside Act 1981, as they are known to be vulnerable to changes to their habitat10. It has been found at two locations, both close to Chatham and upstream of the landfall. The tentacled lagoon worm occurs within subtidal mud and in areas which are less saline than the middle and lower reaches of the Medway Estuary and the vicinity of the landfall11 12 13. Regional seas are being defined for implementing UK nature conservation strategy. The proposed cable route is situated within Regional Sea No. 2, ‘Southern North Sea’14. In addition, Natural
7 Halcrow Group Limited, (2010). Medway Estuary and Swale Shoreline Management Plan. [online] Available at: http://www.medway.gov.uk/pdf/Medway%20Estuary%20and%20Swale%20Shoreline%20Management%20Plan%202010.pdf (accessed 16/01/2017) 8 Kent and Essex IFCA, (2015) Impact Assessment of measures to protect a fish nursery area in the Medway Draft 31/07/2015 9 Joint Nature Conservation Committee (JNCC) and Natural England (NE) (2012). JNCC and Natural England’s advice to Defra on recommended Marine Conservation Zones. Peterborough: Joint Nature Conservation Committee(JNCC) 10 Institute of Environmental Management and Assessment (IEMA), (no date). [online]. Available at: http://www.iema.net/assets/uploads/EIA%20Articles/campbellreith_article_out_of_sight_out_of_mind.pdf (accessed 13/01/2017). 11 Worlsfold T M, Grist N C and Hunter P. (2004). Review of intertidal invertebrate data available for the Medway, Swale and North Kent Marshes estuary systems, with recommendations for future work. Unicomarine Report to the Medway and Swale Estuaries Partnership. 12 Rooks C, Schmid M C, Mehsaha W and Trimmer M. (2012). The depth specific significance and relative abundance of anaerobic ammonium oxidizing bacteria in estuarine sediments (Medway Estuary, UK). FEMS Microbiology Ecology, 80, 19-29 13 Natural England (2015) The Medway Estuary Marine Conservation Zone DRAFT supplementary advice on conserving and restoring site features. [online]. Available at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/485002/medway-estuary- mzc- supplementary-advice.pdf (accessed 13/01/2017) 14 JNCC (Joint Nature Conservation Committee), (2009). Developing regional seas for UK waters using biogeographic principles. Report by Joint Nature Conservation Committee to the Department for Environment, Food and Rural Affairs (DEFRA), 12pp
46 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
England has developed Marine Natural Areas which take account of natural processes and interaction between them, the underlying geology and wildlife. They offer a biogeographic framework within which to develop and implement an ecosystem approach to managing human uses of the marine environment. GridLink is within the ‘Southern North Sea Marine Natural Area’15. Benthic data derived from the European Marine Observation Data Network (EMODnet) Seabed Habitats project shows that the proposed cable route coincides with commonly occurring infralittoral and circalittoral habitats that are widely distributed within the southern North Sea region. A range of different sediment types are recorded along the proposed cable route, including coarse, sand, muddy and mixed sediments. Broad-scale trawling of seabed communities throughout the North Sea has previously identified characteristic faunal groups in the different regions16 17. Stations located in the most southerly section of the southern North Sea and corresponding to the location of the proposed cable route were typified by epifaunal species, including common hermit crab Pagurus bernhardus, flying crab Liocarcinus holsatus, brown shrimps Crangon allmanni and C. crangon, brittlestar Ophiura albida and common starfish Asterias rubens. Infauna species included polychaetes Glycera lapidum, Polycirrus spp., Ross worm Sabellaria spinulosa, catworms Nephtys caeca and N. cirrosa, mysid shrimp Gastrosacchus spinifer, shovelhead worm Magelona johnstoni and the gammarid amphipod Urothoe brevicornis. 7.3 Mitigation Measures The proposed method of cable installation through the intertidal zone will be Horizontal Directional Drilling (HDD) to pass underneath intertidal benthic communities without disturbing the surface. Where possible, vessels operating within the Medway Estuary will also utilise dynamic positioning, which will minimise the interaction with the seabed. This will reduce the interactions between the benthic ecology and the vessels operating during the construction phase of the Proposed Development. Furthermore, following the benthic survey of the proposed cable route, should areas of importance to benthic ecology be identified, wherever practicable the cable will be micro-routed to avoid direct effects. If it is not possible to avoid direct impact then a cable route will be chosen which minimises the effects of the Proposed Development on these areas as much as possible. 7.4 Potential Effects to be Excluded from the EA The potential effects on benthic ecology that are proposed to be excluded from the EA are defined in Table 7-1.
15 Jones L A, Coyle M D, Evans D, Gilliland P M and Murray A R. (2004). Southern North Sea Marine Area Profile: A contribution to regional planning and management of the seas around England. English Nature: Peterborough 16 Callaway R, Alsvåg J, De Boois I, Cotter J, Ford A, Hinz H, Jennings S, Kröncke I, Lancaster J, Piet G, Prince P and Ehrich S. (2002). Diversity and community structure of epibenthic invertebrates and fish in the North Sea. ICES Journal of Marine Science, 59, 1199-1214 17 Reiss H, Degraer S, Duineveld G C A, Kröncke I, Aldridge J, Craeymeersch J, Eggleton J D, Hillewaert H, Lavaleye M S S, Moll A, Pohlmann T, Rachor E, Robertson M, vanden Berghe E, van Hoey G, and Rees H L. (2010). Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea. ICES Journal of Marine Science, 6, 278–293
47 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Table 7-1 Effects on Benthic Ecology to be Excluded from the EA
Potential Phase of Project Rationale for Exclusion Effect Siltation rate Construction and There are two pathways for species to be smothered through changes, maintenance temporary sediment disturbance due to project activities: by including displaced sediments during trenching and by the re-deposition of smothering suspended sediment. The impact from displaced sediment will be (depth of very localised, only effecting species in the immediate vicinity of cable vertical trenches. The generation of suspended sediments followed by re- sediment deposition during trenching are expected to be minimal with any overburden): material deposited likely to be quickly re-suspended and distributed by natural hydrodynamic processes. Changes in Construction and Construction works will displace sediment which will temporarily suspended maintenance increase turbidity before being rapidly dispersed through natural solids (water hydrodynamic processes. Any increase in turbidity is likely to be clarity) within natural variability and benthic species will be accustomed to such variations Temperature Operation The cable will either be buried or protected by rock placement. Any changes – temperature changes will be localised to the immediate soil local surrounding the cable and undetectable against natural temperature fluctuations in the surrounding sediments and water column. Electromagne Operation Benthic communities are typified by sessile or low-mobility species, tic changes which are unlikely to navigate using magnetic fields, therefore they are less likely to be impacted than more mobile species such as teleost fish, elasmobranchs and cetaceans. However, given stakeholder feedback and concern surrounding EMF on other recent cable projects, effects of EMF on benthic communities will be assessed.
7.5 Potential Effects to be Included in the EA The potential effects on benthic ecology that are proposed to be included in the EA are summarised in Table 6.2.
Table 7-2 Effects on Benthic Ecology to be Included in the EA
Potential Effect Phase of Project Rationale for Inclusion
Physical change (to Construction External protection using rock placement or concrete another seabed type) mattresses will be used to protect the cable in certain areas where burial is not possible, in particular third party infrastructure crossings. This may alter the benthic habitats either directly through a change in the substrate (e.g. form sand to rock), or indirectly as a result in changes to hydrodynamic processes effecting sediment transport, which in turn may result in changes to the community structure.
48 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Potential Effect Phase of Project Rationale for Inclusion
Penetration and/or Construction Benthic communities in the zone of influence of the marine disturbance of the cables will be impacted through substratum loss and direct substrate below the displacement during cable laying and maintenance surface of the seabed, operations. The significance of the impact varies according including abrasion to the technique of cable burial employed (e.g. jet or plough (change to seabed trenching) and the sensitivity of the habitat. It is likely that in features) most cases any impacts to species and habitats will be localised and short term and once installed the substratum will be reinstated over the cable. There will be no disturbance to intertidal species due to the used of horizontal directional drilling (HDD) to cross the shoreline. However, the benthic environment may be disturbed as a result of vessel anchoring and at the HDD break out location. The effects on the seabed will be highly localised and temporary in nature. It is also highly likely that the habitats and species disturbed during anchoring will recolonise the area once the anchors have been removed. However, notwithstanding the above, it is recognised that localised disturbance of species within the Margate and Long Sands SAC, Goodwin Sands rMCZ and Offshore Foreland rMCZ is of concern to Natural England. Transition elements Construction Whilst the increase in turbidity is not considered to be a and organo-metal potentially significant effect, the Medway Estuary is likely to contamination be polluted due to its historic activities. Indirect effects from the mobilisation of contaminants may affect the benthic ecology and may enter the food chain.
7.6 Additional Baseline Information and Collection Methods A desk-based assessment will be undertaken to determine the existing information with regards to the proposed cable route and benthic ecology. Consultation will be undertaken with the following bodies to ensure that the most up to date information is collated regarding the existing benthic environment: ▪ MMO; ▪ Medway Council; ▪ Cefas; ▪ Natural England; ▪ Joint Nature Conservation Committee; ▪ Kent and Essex Inshore Fisheries and Conservation Authority; and ▪ Kent Wildlife Trust A benthic survey will be undertaken to characterise the proposed cable route and its immediate vicinity. The survey utilises techniques such as drop down video (DDV) and benthic grabs. The scope of the survey will be confirmed with the MMO, Natural England and JNCC prior to the survey being undertaken to confirm acceptability for the purposes of supporting the EA. It is anticipated that once
49 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
the benthic survey is complete, the results will be used to micro- route the proposed cable route within the survey corridor to avoid any previously unknown protected or notable species or habitats. 7.7 Appraisal of Potential Effects Following completion of the benthic survey and micro-routing of the proposed cable route within the survey corridor, a risk-based assessment will be undertaken to identify any potentially significant ecological effects of the Proposed Development on the benthic habitats and species. Effects will be determined based on a qualitative appraisal of the potential for sensitive receptors to be affected by the Proposed Development. The determination of significance will be based on expert judgement, taking into account factors such as sensitivity and vulnerability of receptors, duration of the activity being considered that gives rise to the effect, permanence of the effect and recoverability of the receptor. Measures to mitigate potentially significant effects will be proposed as appropriate.
50 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
8. MARINE AND COASTAL BIRDS 8.1 Introduction This chapter describes the marine and coastal birds present near the proposed cable route and in the wider area encompassing the Medway Estuary, Outer Thames Estuary and southern North Sea due to the mobile nature of these receptors. It provides the rationale for excluding certain interactions from further consideration; and for those which are to be considered further, it explains the proposed approach to additional baseline characterisation and to the subsequent appraisal of the effects of the Proposed Development. 8.2 Baseline Conditions The southern North Sea (SNS) and its adjacent coastlines are important for a wide range of nationally and internationally important seabird populations, acting as both breeding sites and foraging areas. Seabird distribution is influenced by various factors, probably the most important of which is the availability of food18. The distribution and abundance of all seabird species varies throughout the year. Due to the highly mobile nature of seabirds and their food sources, any areas of high density are likely to change between seasons and years19.
8.2.1 Protected sites The proposed cable route passes through the Medway Estuary and Marshes SPA/Ramsar site for 200 m by horizontal directional drilling, the Outer Thames Estuary SPA for 49-50 km and is 200 m from the Thames Estuary and Marshes SPA/Ramsar site, all of which are designated for the protection of birds. ▪ The Medway Estuary and Marshes SPA/Ramsar is important for waterfowl throughout the year and for little tern during the breeding season. The SPA also regularly supports internationally or nationally important wintering assemblage of waterfowl. ▪ The Outer Thames Estuary SPA is classified for the protection of the largest aggregation of wintering red-throated diver (Gavia stellate) in the UK with an estimated population of 6,466 individuals, which is 38% of the wintering population of Great Britain. It also protects foraging areas for common tern (Sterna hirundo) and little tern (Sternula albifrons) during the breeding season. ▪ The Thames Estuary and Marshes SPA/Ramsar supports an internationally important assemblage of wintering waterbirds including grebes, geese, ducks and waders within the estuary and adjacent grazing marsh areas. The site is also important in spring and autumn migration periods and is important for over wintering hen harrier. Other protected sites for birds close to the cable route are summarised below: ▪ Benfleet and Southend Marshes SPA, which is 2-3 km from the cable route, is important over winter for individual waterfowl individual species and an internationally important assemblage. ▪ The Swale SPA/Ramsar, which is 9-10 km from the cable route, is important for waterfowl throughout the year including an over winter assemblage of international importance; marsh harrier (Circus aeruginosus) and Mediterranean gull (Larus melanocephalus) during the breeding season; and hen harrier (Circus cyaneus) over winter.
18 Stone, C.J., Webb, A., Barton, C., Ratcliffe, N., Reed, T.C., Tasker, M.L., Camphuysen, C.J. and Pienkowski, M.W. 1995. An atlas of seabird distribution in north-west European waters, ISBN 1 873701 94 2, 324pp. 19 Forewind (2013). Dogger Bank Creyke Beck Environmental Statement Chapter 11 Appendix A- Ornithology Technical Report. BTO Research Report No 630.
51 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
▪ Foulness (mid-Essex Coast Phase 5) SPA/Ramsar, which is 2-3 km from the cable route, supports important populations of waterfowl throughout the year; common tern (Sterna hirundo), little tern (Sterna albifrons), and Sandwich tern (Sterna sandvicensis) during the breeding season; and hen harrier over winter. ▪ Thanet Coast and Sandwich Bay SPA, which is 15 km from the cable route, is important for over wintering Turnstone (Arenaria interpres) a wader. It is also used by large numbers of migratory birds in spring and autumn. ▪ Dungerness, Romney Marsh and Rye Bay SPA, which is approximately 46km from the cable route, during the breeding season supports marsh harrier, Mediterranean gull, Sandwich tern, common tern and little tern. It also supports a number of waterfowl over winter and Avocet during the breeding season. Marsh harrier is a terrestrial species known to breed within the Medway Estuary and Marshes SPA/Ramsar and Thames Estuary and Marshes SPA/Ramsar; although it is not a qualifying feature of either sites designation. Marsh harrier is listed on Schedule 1 of the Wildlife and Countryside Act 1981, therefore it is an offence to intentionally or recklessly disturb breeding and nesting birds. The effects of the Proposed Development on this species will be assessed within the Environmental Appraisal of the onshore components of the project. 8.3 Mitigation Measures The proposed method of cable installation through the intertidal zone will be Horizontal Directional Drilling (HDD) to minimise impacts on intertidal benthic communities. This in turn will mitigate any indirect effects on prey items of intertidal birds. The cable will be buried wherever possible, with the burial depth dependent on the results of a burial risk assessment. The extent of cable route requiring external protection, i.e. by rock placement or concrete mattressing, will be minimised. Sediment will also be back filled into the trench following installation of the cable although natural hydrodynamic processes are likely to bury the cable relatively quickly. Where practicable, cable laying operations and maintenance activities will be scheduled at times of the year that minimises the likelihood of marine and coastal birds being disturbed. 8.4 Potential Effects to be Excluded from the EA The potential effects on marine and coastal birds that are proposed to be excluded from the EA are defined in Table 8-1. Table 8-1 Effects on Marine and Coastal Birds to be Excluded from the EA
Potential Effect Phase of Project Rational for Exclusion Penetration Construction and Changes in prey availability is a potential indirect and/or maintenance pressure on marine and coastal birds which could disturbance of arise from impacts on fish and shellfish and benthic the substrate species through the disturbance of sediments during below the surface cable installation and maintenance activities. The of the seabed, preferred method of cable installation within the including intertidal area is horizontal directional drilling (HDD) abrasion (change at 10-15 m below ground level, and therefore there to seabed will be no impacts to species. Disturbance to the features) seabed at the breakout point of the HDD and along the cable installation trench will be localised and short term. Given the wider availability of habitat any
52 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Potential Effect Phase of Project Rational for Exclusion temporary effects on changes to prey availability are unlikely to be significant.
8.5 Potential Effects to be Included in the EA The potential environmental effects on marine and coastal birds that are proposed to be included in the EA are summarised in Table 8-2. Table 8-2 Effects on Marine and Coastal Birds to be Included in the EA
Potential Effect Phase of Project Rational for Inclusion Physical change Construction Changes in prey availability is a potential indirect (to another pressure on marine and coastal birds which could seabed type) arise from impacts on fish and shellfish and benthic species through the introduction of rock protection. The placement of rock protection at cable crossings and any areas of the cable route where, due to seabed conditions, target burial depths cannot be achieved, will result in an introduction of a new substrate and possible new habitat with long term effects. Visual Construction During cable installation and maintenance (repair) disturbance Maintenance activities, the presence of project vessels/equipment could result in a temporary disturbance to birds in the immediate vicinity of the works. Noise is the primary cause of disturbance although the physical presence of vessels/equipment can also cause a disturbance effect due to physical and visual intrusion. Disturbance may result in displacement of birds from an area of use (for feeding, breeding, resting, passage etc.). Given the localised and temporary nature of disturbance, this impact is unlikely to be significant for disturbance of feeding and foraging birds as they are likely to be able to find alternative feeding grounds. This impact would be of potential concern where disturbance could have implications for breeding success, for example disturbance of nesting birds during the breeding season, given the proximity of a number of protected sites designated for birds to the cable route.
8.6 Additional Baseline Information and Collection Methods A desk-based review of publicly available information will be used to characterise the sensitivity of coastal and marine birds in and around the proposed marine cable route. Over-wintering, breeding and nesting bird surveys have been conducted to inform the EA. Relevant information, such as bird counts, will be requested from relevant consultees such as Natural England and JNCC, which will inform the assessment of sensitivity of birds near the proposed cable route.
53 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
8.7 Appraisal of Potential Effects Following collation of information on the baseline environment, an assessment will be undertaken to identify any potentially significant effects of the Proposed Development on marine and coastal birds. Effects will be determined based on a qualitative appraisal of the potential for sensitive receptors to be affected by the Proposed Development. The determination of significance will be based on expert judgement, taking into account factors such as sensitivity and vulnerability of receptors, duration of the activity being considered that gives rise to the effect, permanence of the effect and recoverability of the receptor. Measures to mitigate potentially significant effects will be proposed as appropriate.
54 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
9. MARINE MAMMALS 9.1 Introduction This chapter describes the marine mammals present in the immediate vicinity of the proposed cable route as well as the wider area encompassing the Medway Estuary, Outer Thames Estuary and southern North Sea due to the mobile nature of these receptors. It provides the rationale for excluding certain interactions from further consideration and, for those which are to be considered further, it explains the proposed approach to additional baseline characterisation and to the subsequent appraisal of the effects of the Proposed Development. 9.2 Baseline Conditions Marine mammals occurring in UK waters comprise two groups: cetaceans (whales, dolphins and porpoises) and pinnipeds (true seals and eared seals). In terms of diversity in UK waters, 29 species of cetacean20 have been recorded and two species of seal live and breed21.
9.2.1 Cetaceans Cetacean fauna found within the southern North Sea is considered to be low in diversity and abundance compared to other areas of UK territorial waters. Fourteen species of cetacean have been recorded in the waters of the southern North Sea with the most frequently sighted species in nearshore waters (within 60 km of the coastline) being harbour porpoise (Phocoena phocoena) and bottlenose dolphin (Tursiops truncatus)22. Offshore, white- beaked dolphin (Lagenorhynchus albirostris) have been recorded23 and short-beaked common dolphin (Delphinus delphis) are recorded occasionally. Sperm whale (Physeter macrocephalus), humpback whale (Megaptera novaeangliae), northern bottlenose whale (Hyperoodon ampullatus), killer whale (Orcinus orca), fin whale (Balaenoptera physalus), minke whale (Baleanoptera acutorostrata), long-finned pilot whale (Globicephala melas), Risso’s dolphin (Grampus griseus), Atlantic white-sided dolphin (Lagenorhynchus acutus), and striped dolphin (Stenella coeruleoalba) are uncommon visitors to the southern North Sea24 25.
9.2.2 Pinnipeds Grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina) (also called common seals) live and breed in UK waters. Both species breed at haul out sites along the Kent coast, Thames Estuary and Norfolk coast18.
20 Sea Watch Foundation (2017). Species Fact Sheets [online]. Available at: http://www.seawatchfoundation.org.uk/information-and-fact- sheets/ (accessed 09/01/2017) 21 SCOS (2015). Scientific Advice on Matters Related to the Management of Seal Populations: 2015 [online]. Available at: http://www.smru.st- andrews.ac.uk/research-policy/scos/ (accessed 09/01/2017) 22 Sea Watch Foundation (undated). Cetaceans of south-east England [online]. Available at: http://seawatchfoundation.org.uk/wp- content/uploads/2012/07/South-eastEngland.pdf (accessed 09/01/2017) 23 Galloper Windfarm Limited (2011). Galloper Windfarm Project Environmental Statement – Chapter 14 Marine Mammals [online]. Available at: https://infrastructure.planninginspectorate.gov.uk/projects/eastern/galloper-offshore-wind- farm/?ipcsection=docs&stage=app&filter1=Environmental+Statement (accessed 10/01/2017) 24 Reid J B, Evans P G H and Northridge SP, (2003). Atlas of Cetacean distribution in north-west European waters, 76 pages, colour photos, maps. Paperback, ISBN 1 86107 550 2 25 DECC (2009). UK Offshore Energy Strategic Environmental Assessment: Future Leasing for Offshore Wind Farms and Licensing for Offshore Oil and Gas and Gas Storage Environmental Report. DECC, London, 339p (excluding appendices)
55 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
There are an estimated 1,000 seals in the south and southeast regions, two thirds of which are grey seals with a smaller number of harbour seals26. The Special Committee on Seals (SCOS) (2015)18 reports an increase in grey seal pup production in colonies in southeast England and a stable population of harbour seals. This harbour seal population has returned to its pre-2002 Phocine Distemper Virus (PDV) epidemic levels, but is still lagging behind the rapid recovery of other harbour seal populations.
9.2.3 Presence of Marine Mammals Recent opportunistic sightings data reported to the Sea Watch Foundation recorded the presence of cetaceans in the vicinity of the proposed cable route and the coastline of southeast England from Burnham-on-Crouch to Dover. These data totalled eight sightings of 13 harbour porpoise in 2016, and four sightings of six harbour porpoise in 201527. A report by the Kent Mammal Group (201228) records two sightings of approximately nine white- beaked dolphin in the eastern English Channel that year. However, no recent opportunistic sightings of this species near the proposed cable route and the coastline of southeast England from Burnham- on-Crouch to Dover were reported to the Sea Watch Foundation. Recent research by the Zoological Society of London (ZSL) shows a relatively stable population of harbour seals in the Greater Thames area (Felixstowe, Suffolk to Deal, Kent) with populations of grey seals in the summer months believed to be increasing29. The Thames Estuary harbour seal population is becoming increasingly important at a national level26 and currently represents approximately 14% of the recorded English harbour seal population (using SCOS18 figures).
9.2.4 Sites with Marine Mammals as Qualifying Features The southern North Sea candidate Special Area of Conservation (cSAC) has been designated for harbour porpoise. The proposed cable route crosses this site for approximately 21 km. Stretching from the central North Sea (north of Dogger Bank) to the Straits of Dover, the site includes key winter and summer habitat for the species. It covers an area of 36,951 km2 and includes a mix of habitats, such as sandbanks and gravel beds. The cSAC site has been proposed to assist in the management of harbour porpoise numbers in UK waters, and is part of a larger suite of sites. Based on data collected during the SCANS-II survey, it is estimated that the cSAC site potentially supports approximately 18,500 harbour porpoise for at least part of the year. The European Atlantic Shelf harbour porpoise population is estimated to be 375,358 individuals, with the UK sector of the North Sea Management Unit population estimated to be 110,433 individuals. The cSAC site therefore potentially supports 17.5% of the harbour porpoise population within the UK sector of the North Sea Management Unit. Population estimates have been re-assessed recently and the latest SCANS-III surveys indicate that the whole North Sea population could be as high as 345,373 individuals30.
26 Balanced Seas (2011). Goodwin Sands rMCZ Selection Assessment Document [online]. Available at: http://webarchive.nationalarchives.gov.uk/20120502155440/http:/www.balancedseas.org/page/RSG%20Resources.html (accessed 10/01/2017) 27 Sea Watch Foundation (2017). Recent sightings Eastern England [online]. Available at: http://seawatchfoundation.org.uk/legacy_tools/region.php?output_region=6 (accessed 09/01/2017) 28 Kent Mammal Group (2012). 2012 Mammal Report. John Young, KMG Mammal Recorder [online]. Available at: http://www.kentmammalgroup.org.uk/index.php?option=com_docman&task=cat_view&gid=44&Itemid=86 (accessed 09/01/2017) 29 ZSL (2015). Greater Thames Estuary Seal Surveys Report [online]. Available at: http://www.zsl.org/sites/default/files/media/2015- 07/2015_July_Greater%20Thames%20Estuary%20Seal%20Survey%20Report.pdf (accessed 09/01/2017) 30 BEIS (2017). Scoping for Southern North Sea cSAC Review of Consents. September 2017 [online] Available at: https://itportal.beis.gov.uk/EIP/pages/ola/Annex_B_HRA_Review_of_consents_scoping_document.pdf (Accessed April 2018)
56 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
The cSAC has been recognised as an area with predicted persistent high densities of harbour porpoise. Seasonal differences in the relative use of the site have been identified; with the north of the site being of greater importance during the summer season (April to September), and the south being of greater importance during the winter (October to March). The cable route traverses through the southern part of the cSAC that is more important in winter. Heinanen and Skov (2015)31 provides distribution maps that indicate observed summer densities of harbour porpoise in the region surrounding the cable route are <0.3 animals per km2 for the period 1994 – 2011. In winter, predicted densities increase to >3 animals per km2 (modelled data for 1997, 2004 and 2009). 9.3 Mitigation Measures As the distribution and abundance of marine mammals (both cetaceans and pinnipeds) in the wider area of the southern North Sea varies seasonally, where practicable cable-laying activities with the potential to affect these receptors will be scheduled at times of the year that minimises the likelihood of marine mammal presence along the cable route. Vessels operating during the construction phase of the development are also likely to be slow moving at 200-400 m per hour, which will allow time for any marine mammals to avoid interaction. In accordance with best practices following the JNCC guidelines (2017)32 and in consultation with Natural England and JNCC, the following mitigation measures will be implemented: ▪ A Marine Mammal Observer (MMO) will be deployed for the offshore survey within the southern North Sea cSAC. ▪ Soft starts will be used for the sub bottom profiler equipment within the southern North Sea cSAC and delayed if marine mammals are present with the mitigation zone (as per the JNCC guidelines). 9.4 Potential Effects to be Excluded from the EA The potential effects on marine mammals that are proposed to be excluded from the EA are defined in Table 9-1. Table 9-1 Effects on Marine Mammals to be Excluded from the EA
Potential effect Phase of Project Rational for Exclusion
Temperature changes Operation The cable will either by buried or protected by rock placement. (local) Any residual effects are considered to be localised and undetectable against natural temperature fluctuations in the surrounding sediments and water column. These will mitigate any potential effects as a result of thermal changes to marine mammals.
31 Heinanen, S. and Skov, H. (2015). The identification of discrete and persistent areas of relatively high harbour porpoise density in the wider UK marine area. JNCC report No. 544. [online] Available at: http://jncc.defra.gov.uk/pdf/JNCC_Report%20544_web.pdf (Accessed April 2018). 32 JNCC (2017). JNCC guidelines for minimising the risk of injury to marine mammals from geophysical surveys. August 2017. [online] Available at: http://jncc.defra.gov.uk/pdf/jncc_guidelines_seismicsurvey_aug2017.pdf (Accessed January 2018)
57 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Potential effect Phase of Project Rational for Exclusion
Visual disturbance Construction The physical presence of project vessels during construction Maintenance and maintenance (repair) has the potential to disturb marine mammals. Harbour porpoise are the designating feature of the southern North Sea cSAC and may be present along the cable route and grey seal are known to haul out on Goodwin sands. The region is already used by large ships and ferries, particularly in the area surrounding the proposed cable route. The addition of installation / maintenance vessels is unlikely to be noticeable against the background of normal shipping activity fluctuations. In addition, the activities will be temporary and transient, with the vessel moving slowly through the region. Therefore, no likely significant effects of disturbance to harbour porpoise or pinniped are expected from the presence of project vessels.
9.5 Potential Effects to be Included in the EA The potential effects on marine mammals that are proposed to be included from the EA are defined in Table 9-2. Table 9-2 Effects on Marine Mammals to be Included from the EA
Potential Effect Phase of Rationale for Inclusion Project Electromagnetic Operation Electromagnetic fields have the potential to interfere with changes electro-sensitive marine species. Due to the bundled, bi-polar design of the cable with the current in each cable flowing in opposite directions, the magnetic fields in each cable will cancel each other out. The electric field generated by the cables will be mitigated through metallic screening of the cables and burial below the seabed. However, any possible effect on electro- sensitive marine species is a sensitive issue. Underwater noise Construction Both cetaceans and pinnipeds are sensitive to increased levels of changes Maintenance underwater noise, which can induce a range of effects on animals. These range from behavioural changes to non-injurious effects, such as masking communication signals, to temporary or permanent auditory injuries. Project vessels, cable burial machinery, cable protection placement, marine surveys and, if necessary, detonation of UXO will all generate underwater noise.
9.6 Additional Baseline Information and Collection Methods Extensive information is available regarding marine mammals near the proposed cable route and the sea areas that it passes through. It is therefore proposed to use this information for the assessment of the effects of the Proposed Development on marine mammals. No site-specific field survey is proposed. The impact assessment will be undertaken using baseline data on distribution, abundance and species-specific information on marine mammal sensitivities, behaviour and habitats. Consultation
58 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
will be undertaken with the following bodies, as a minimum, to ensure that the most up to date information is collated regarding the existing baseline environment: ▪ MMO; ▪ Cefas; ▪ Natural England; ▪ Joint Nature Conservation Committee; ▪ Kent Wildlife Trust; ▪ Whale and Dolphin Conservation; ▪ British Divers Marine Life Rescue; ▪ Kent and Essex Inshore Fisheries Conservation Authority; and ▪ Zoological Society of London. 9.7 Appraisal of Potential Effects Following collation of information on the baseline environment, an assessment will be undertaken to identify any potentially significant effects of the Proposed Development on marine mammals. Effects will be determined based on a qualitative appraisal of the potential for sensitive receptors to be affected by the Proposed Development, taking into account the scale and extent of the potential effect. The determination of significance will be based on expert judgement, taking into account factors such as sensitivity and vulnerability of receptors, duration of the activity being considered that gives rise to the effect, permanence of the effect and recoverability of the receptor. Measures to mitigate potentially significant effects will be proposed as appropriate. A marine mammal risk assessment, using injury criteria proposed by NMFS (2016), will be conducted as part of the EA to assess the potential for noise to harm or disturb different species of marine mammals.
59 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
10. FISHERIES 10.1 Introduction This chapter describes fish and shellfish ecology, including species of conservation concern and commercial fisheries. It provides the rationale for excluding certain interactions from further consideration and, for those which are to be considered further, it explains the proposed approach to additional baseline characterisation and to the subsequent appraisal of the effects of the Proposed Development on those aspects of fisheries. 10.2 Baseline Conditions
10.2.1 Fish and Shellfish Ecology The estuaries and subtidal habitats of the Medway Estuary support a variety of fish and shellfish. Fish species present range from adventitious freshwater species, i.e. freshwater species with no estuarine requirement, to adventitious marine species, i.e. marine species with no estuarine requirement. The intertidal area is an important nursery area for many of these commercially important fish species, and the intertidal area of the Medway Estuary performs a key local, regional and national role as a nursery area for a number of key commercial fish stocks. Many of the species listed below use the intertidal areas of the estuary during juvenile stages33. The Medway Estuary has two protected nursery grounds for bass34; these are adjacent to the power station outfalls at Kingsnorth and Isle of Grain (Figure 10-1). Diadromous species which migrate between freshwater and marine environments are also known to occur within the vicinity of the proposed cable route. These include the European eel (Anguilla Anguilla), smelt (Osmerus eperlanus) and Sea lamprey (Petromyzon marinus). Important shellfish within the area include the cockle (Cardium edule), native oyster (Ostrea edulis), Pacific oyster (Crassostrea gigas) and the blue mussel (Mytilus edulis). The Proposed Development directly interacts with several fish spawning and nursery areas as the proposed cable route passes through the spawning and nursery grounds of 12 commercially important fish species, as presented in Table 10-1. High intensity spawning grounds for plaice and sole and high intensity nursery grounds for herring, sole and seabass have been identified. The peak spawning period for plaice is January-February and for sole April. This first third of the year is also a time that coincides with the peak upstream (inshore) movements of smelt, sea lamprey and European eel, which are listed under Annex II of the EC Habitats Directive and the UK Biodiversity Action Plan (BAP) list.
33 Environment Agency (2010). Marine fish nursery function in the Medway Estuary. Report for Environment Agency. In: Impact Assessment of measures to protect a fish nursery area in the Medway Draft report. Kent and Essex IFCA (2015) 34 The Bass Order (1990). The Bass (Specified Areas) (Prohibition of Fishing) Order 1990. Statutory Instrument 1990 No. 1156 [online]. Available at: http://www.uklaws.org/statutory/instruments_05/doc05265.htm (accessed 13/01/2017)
60 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Table 10-1 Fish Species with Spawning and/or Nursery Grounds within the cable route35 36 37
Species Spawning Grounds Nursery Grounds
Cod (Gadus morhua) Low intensity Low intensity Herring (Clupea herrengis) Present High intensity Lemon sole (Microstomus kitt) Present Present Mackerel (Scromber scrombus) No interaction Present Plaice (Pleuronectes platessa) High intensity Low intensity Sandeels (Ammodytidae) Low intensity Low intensity Sole (Solea solea) High intensity High intensity Sprat (Sprattus sprattus) Present Present Thornback Ray (Raja clavata) Insufficient data Low intensity Tope (Galeorhinus galeus) Insufficient data Low intensity Whiting (Merlangius merlangus) No interaction Low intensity Seabass (Dicentrarchus labrax) Insufficient data High intensity (intertidal)
Data Source: Ellis et al (2012), Spawning and nursery grounds of selected fish species in UK waters. The terms: present, low intensity, high intensity and insufficient data are used to describe the survey results in terms of occurrence and relative abundance of eggs or juveniles found in a given area.
35 Ellis J R, Milligan S P, Readdy L, Taylor N and Brown M J. (2012). Spawning and nursery grounds of selected fish species in UK waters. Cefas Scientific Series Technical Report 147. Available at: http://www.cefas.defra.gov.uk/publications/techrep/TechRep147.pdf 36 Coull K A, Johnstone R, and Rogers SI. (1998). Fisheries Sensitivity Maps in British Waters. Published and distributed by UKOOA Ltd. 37 Kent and Essex IFCA (2015). Impact Assessment of measures to protect a fish nursery area in the Medway Draft 31/07/2015
61 P2114_R4493_Rev2 | 16 August 2018
332000 336000 GRIDLINK INTERCONNECTOR 0 0 0 0
0 0 SCOPING REPORT 4 4 0 0 7 7 5 . 5 Figure 10-1: Medway Bass Nursery Area . Legend 'South of BritNed' Preferred HVDC Cable Route 'North of BritNed' Alternative HVDC Cable Route Median Line Medway Bass Nursery Area 0 0 0 0 0 0 0 0 0 0 7 7 5 5
NOTE: Not to be used for Navigation
Date Friday, June 29, 2018 09:23:29 Projection WGS_1984_UTM_Zone_31N Spheroid WGS_1984 Datum D_WGS_1984
Data Source ESRI, ELANENERGY, CDA, UKHO, CEFAS
J:\P2114\Mxd\Scoping_Report\ File Reference Fig_10_1_Bass_Nursery_Area.mxd Created By Jennifer Arthur 0 0 0 0
0 0 Reviewed By Richard Marlow 6 6 9 9
6 6 Approved By Anna Farley 5 5
km © Metoc Ltd, 2018. 332000 336000 0 0.5 1 1.5 2 All rights reserved. © Esri, 2018; © Crown Copyright. Contains public sector information licensed under Open Government Licence v3.0. Contains public sector information, licensed under the Open Government Licence v2.0, from the UKHO, 2013. Contains public sector information licensed under the Open Government Licence v3.0. 360000 450000 360000 450000 360000 450000 360000 450000 GRIDLINK INTERCONNECTOR Sprat Sandeel Plaice Cod SCOPING REPORT
Figure 10-2 Spawning and Nursery Grounds 5760000 . 5760000 Legend 'South of BritNed' Preferred Route Tope Shark
'North of BritNed' Alternative Route Nursery Median Line Thornback Ray 12nm Territorial Sea Limit Nursery Sprat Mackerel 5670000 5670000 Nursery Nursery Spawning Herring Whiting Nursery Nursery Lemon Sole Spawning Nursery Sole Spawning Nursery Sole Tope Shark Thornback Ray Mackerel Horse Mackerel Spawning Spawning Sandeel
5760000 5760000 Nursery Spawning Plaice
Nursery Spawning
High Intensity
5670000 5670000 Low Intensity Cod
Nursery Spawning
High Intensity Low Intensity Whiting Herring Lemon Sole Horse Mackerel
NOTE: Not to be used for Navigation
Date Friday, June 29, 2018 09:24:09 5760000 5760000 Projection WGS_1984_UTM_Zone_31N Spheroid WGS_1984 Datum D_WGS_1984
Data Source ESRI, ELANENERGY, CEFAS, IFCA
J:\P2114\Mxd\Scoping_Report\ File Reference Fig_10_2_Spawning_and_Nursery.mxd Created By Richard Marlow
5670000 5670000 Reviewed By Jennifer Arthur Approved By Anna Farley
km © Metoc Ltd, 2018. 360000 450000 360000 450000 360000 450000 360000 450000 0 30 60 90 120 All rights reserved. © Esri, 2018; © Crown Copyright. Contains public sector information licensed under Open Government Licence v3.0. Contains public sector information, licensed under the Open Government Licence v2.0, from the UKHO, 2013.Contains public sector information licensed under Open Government Licence v3.0. Data from Ellis, J.R. et al. (2012) Spawning and Nursery Grounds of Selected Fish Species in UK Waters. CEFAS Lowestoft Science Series Technical Report, 147: 55pp. GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
10.2.2 Commercial Fisheries The proposed cable route is located within the Kent and Essex Inshore Fisheries and Conservation Authority (KEIFCA) District, which is comprised mainly of <10 m vessels working daily within the 6 nm or 12 nm limits, and occasionally up to about 25 nm from their home port38. The main fishing ports within the district include Dungeness, Folkestone, Ramsgate, and Whitstable in Kent, and Leigh-on- Sea, West Mersea and Harwich in Essex. A number of other smaller ports are also used for beach landing by small vessels, including Herne Bay, Deal, and Hythe39. There is limited fishing activity from the Port of Dover, with two part-time vessels operating in recent years. A variety of static and mobile gears are used within the KEIFCA District including trawling, pair trawling, drift/fixed netting, potting, scallop and oyster dredging and cockle dredging. Different gear is deployed according to the target species, and the type of gear used varies with the seasonal fluctuations of each fishery40. A variety of fish is landed from trawling and netting vessels including Dover sole Solea solea, plaice Pleuronectes platessa, dab Limanda limanda, bass Dicentrarchus labrax, cod Gadus morhua, herring Clupea harengus, sprat Sprattus sprattus, thornback ray Raja clavata, whiting Merlangius merlangus, horse mackerel Trachurus trachurus, Atlantic mackerel Scomber scombrus, lesser weaver Echiichthys vipera, solenette Buglossidium luteum, dragonet Callionymus lyra, and sand goby Pomatoschistus minutus 35 41. Other vessels also land scallops (Aequipecten opercularis and Pecten maximus), native and Pacific oysters (Ostrea edulis and Crassostrea gigas), whelks Buccinum undatum, lobster Homarus gammarus and, to a lesser extent, mussels (Mytilus edulis) and crab. Cockle harvesting in the Thames Estuary is one of the most productive fisheries within the KEIFCA District37. The Thames Estuary supports important commercial fisheries, with the most important commercially fished species being the Dover sole, and the Greater Thames, including Medway and Blackwater estuaries, supports a herring fishery that is recognised as distinct to this region. The Outer Thames Estuary in conjunction with the Medway and Essex estuaries constitutes one of the most important spawning areas in the North Sea, helping to produce fish larvae that support important commercial Channel and southern North Sea fish stocks8. There is also a well-established cockle industry, believed to be the largest in the UK. Other shellfish species harvested in the estuary include mussels and native and Pacific oysters. Parts of the estuary are designated Shellfish Waters (see Figure 10-2). Shellfish waters are designated for the protection of shellfish growth and production. Good water quality is important for the production of high quality shellfish. Water bodies can be impacted by pollution from various sources such as run-off from agricultural land or discharges from sewage treatment works. The Rochester Oyster and Floating Fishery (ROFF) exercises its rights to control the trawling and netting activities in the river as well as fishing of oysters. The Medway Estuary, specifically the intertidal and saltmarsh habitat, performs a key local, regional and national role as a nursery area for a number of key commercial fish stocks. Many of the species listed above use the intertidal areas of the estuary during juvenile stages 27. The estuary has two protected nursery grounds for bass designated under The Bass Order 1990; these are adjacent to the power station outfalls at Kingsnorth and Isle of Grain, in which fishing activity is seasonal, with the main period being March to October.
38 Kent and Essex Sea Fisheries Committee (undated). About the fleet [online]. Available at: http://www.kentandessex- sfc.co.uk/id23.html (accessed 11/01/2017) 39 Callaway R, Alsvåg J, De Boois I, Cotter J, Ford A, Hinz H, Jennings S, Kröncke I, Lancaster J, Piet G, Prince P and Ehrich S. (2002). Diversity and community structure of epibenthic invertebrates and fish in the North Sea. ICES Journal of Marine Science, 59, 1199-1214 40 Reiss H, Degraer S, Duineveld G C A, Kröncke I, Aldridge J, Craeymeersch J, Eggleton J D, Hillewaert H, Lavaleye M S S, Moll A, Pohlmann T, Rachor E, Robertson M, vanden Berghe E, van Hoey G, and Rees H L. (2010). Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea. ICES Journal of Marine Science, 6, 278–293 41 Joint Nature Conservation Committee (2010). DEPARTMENTAL BRIEF: OUTER THAMES ESTUARY Special Protection Area [online]. Available at: http://publications.naturalengland.org.uk/file/3264082 (accessed 10/01/2017)
64 P2114_R4493_Rev2 | 16 August 2018
320000 360000 400000 GRIDLINK INTERCONNECTOR SCOPING REPORT . Figure 10-3: Shellfish Waters WALTON . Legend BACKWATERS 'South of BritNed' Preferred HVDC Cable Route 'North of BritNed' Alternative HVDC Cable Route PYEFLEET Median Line COLNE_E SALCOTT CHANNEL 12nm Territorial Sea Limit TOLLESBURY CHANNEL Shellfish Water
OSEA BLACKWATER ISLAND DENGIE
UPPER CROUCH 0 0
0 ROACH AND 0 0 0
0 LOWER CROUCH 0 2 2 7 7
5 UPPER ROACH 5
OUTER THAMES
FOULNESS
SOUTHEND
SHEPPEY
SWALECLIFFE MARGATE
SWALE CENTRAL SWALE EAST
STOUR ESTUARY (KENT) 0 0
0 0 NOTE: Not to be used for Navigation 0 0 0 0 8 8
6 6 Date Friday, June 29, 2018 09:22:48 5 5 Projection WGS_1984_UTM_Zone_31N Spheroid WGS_1984 Datum D_WGS_1984
Data Source ESRI, ELANENERGY, CDA, UKHO, CEFAS
J:\P2114\Mxd\Scoping_Report\ File Reference Fig_10_3_Shellfish_Waters.mxd Created By Jennifer Arthur Reviewed By Richard Marlow Approved By Anna Farley
km © Metoc Ltd, 2018. 320000 360000 400000 0 5 10 15 20 All rights reserved. © Esri, 2018; © Crown Copyright. Contains public sector information licensed under Open Government Licence v3.0. Contains public sector information, licensed under the Open Government Licence v2.0, from the UKHO, 2013. Contains public sector information licensed under the Open Government Licence v3.0. GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
10.2.3 ICES Rectangle Landings Data The proposed cable route is located within the International Council for the Exploration of the Sea (ICES) fisheries rectangles 31F0 and 31F1. A high-level review of landings data from 2012 to 2016 provided information on the economic importance of commercial fish species, and also an indication of the presence/absence of commercial fish species in the area. The landings data for the period 2012 to 2016 indicate that, in terms of quantity landed and commercial value, the main commercial fish species in these two rectangles are whelks, cod, sole, thornback ray and bass. Other important species include scallops, native oyster, smoothhound (Mustelus spp), Pacific oyster, crabs, skates, rays and plaice. Table 10-2 and Table 10-3 show the landing values (in £GBP) by generic species type for ICES rectangles 31F0 and 31F1 (from MMO UK fleet landings by ICES rectangle data). Table 10-2 Landing Values by Generic Species Types for ICES Rectangle 31F0
Species Value in £ (GBP)
2012 2013 2014 2015 2016
Shellfish 96,451 399,376 839,932 289,736 683,703
Demersal 109,523 58,983 59,429 47,572 48,370
Pelagic 42,164 7474 33,018 16,117 3793
Total landed 248,138 465,833 932,379 353,425 735,866
Table 10-3 Landing values by Generic Species Types for ICES Rectangle 31F1
Species Value in £ (GBP)
2012 2013 2014 2015 2016
Shellfish 911,077 1,828,907 2,632,938 1,844,897 2,091,363
Demersal 1,285,074 1,195,773 1,084,379 1,077,996 1,146,186
Pelagic 3082 68,187 541,064 157,074 54,276
Total landed 2,199,233 3,092,867 4,258,381 3,079,967 3,291,825
10.3 Mitigation Measures The method of cable installation through the intertidal zone is Horizontal Directional Drilling (HDD), which will pass 10-15 m below ground level and avoid any effects on the high intensity fish nursery grounds and the intertidal zone. To inform commercial fishermen of the construction activities, safety information will be provided in accordance with the Maritime and Coastguard Agency (MCA) guidelines and through the United Kingdom Hydrographic Office (UKHO), including Local and National Notice to Mariners. Safety information and notices will include a description of the operation and will be regularly updated to show accurate information on the current location of the construction activities and names of operating vessels, including guard vessels. A Fisheries Liaison Officer (FLO) will be appointed for the duration of the construction works to coordinate the cable lay activities with local fishing organisations and commercial fishing vessels.
66 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
The Kingfisher Information Service (KIS) will also be notified with details of the works and final cable route published in their bulletins. The location of the cable following construction will also be marked on navigational charts to raise awareness of its presence to commercial fishing vessels in the area. 10.4 Potential Effects to be Excluded from the EA The potential effects on fisheries that are proposed to be excluded from the EA are defined in Table 10-4. Table 10-4 Effects on Fisheries to be Excluded from the EA
Potential Effect Phase of Project Rationale for Exclusion Siltation rate Construction and There are two pathways for species to be smothered through changes, including maintenance temporary sediment disturbance due to project activities: by smothering (depth displaced sediments during trenching and by the re-deposition of vertical sediment of suspended sediment. The impact from displaced sediment overburden) will be very localised, only effecting species / eggs in the immediate vicinity of cable trenches. The generation of suspended sediments followed by re-deposition during trenching has the potential to smother sessile and low mobility species or eggs. Suspended sediment settlement levels are expected to be minimal, within levels associated with natural variation, and any material deposited likely to be quickly re- suspended and distributed by natural hydrodynamic processes. Changes in Construction and The suspension of sediments within the water column from suspended solids maintenance cable installation may cause small, localised and temporary (water clarity) turbidity before being re-deposited on the seabed. A temporary reduction in the feeding capability of species relying on sight to locate their prey may occur. Most species are likely to be tolerant to any changes in turbidity levels (likely to be equivalent to those experienced during storm events) and the significance of the impact is likely to be negligible. Physical change (to Construction and External protection will be used to protect the cable in certain another seabed Operation areas where burial is not possible. However, due its limited type) extent, it is unlikely to significantly change the distribution of targeted fish and shellfish species. Temperature Operation Operation of the cables will produce heat as a consequence of changes – local the internal resistance of the conductors. The cables will either by buried or protected by rock placement and it is expected that cable heat will be rapidly dissipated and any heating of the seabed immediately surrounding the cables will be insignificant. Demersal fish species and shellfish in close contact with the seabed are not expected to be impacted. Electromagnetic Operation Electromagnetic fields have the potential to interfere with changes navigational compasses of fishing vessels. Due to the bundled, bi-polar design of the cable with the current in each cable flowing in opposite directions, the magnetic fields in each cable will cancel each other out. The electric field generated by the cables will be mitigated through metallic screening of the cables and burial below the seabed. Near the landfall location, where the cables separate to enter the HDD ducts in shallow water there is the greatest risk of compass deviation being
67 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Potential Effect Phase of Project Rationale for Exclusion experienced; however, no commercial fishing vessels are likely to use this area due to very shallow water depths within Damhead Creek.
Snagging hazard Operation The cable will be buried except where it crosses hard rock seabed or third party infrastructure. As these points, the cable will be protected by rock placement. A post-installation inspection survey will be carried out to ensure that the cables are correctly buried/protected.
10.5 Potential Effects to be Included in the EA The potential effects on fisheries that are proposed to be included from the EA are defined in Table 10-5. Table 10-5 Effects on Fisheries to be Included from the EA
Potential Effect Phase of Project Rationale for Inclusion
Penetration and/or Construction Activities that physically disturb the seabed e.g. cable trenching, disturbance of the have the potential to disturb species with demersal life stages substrate below (i.e. those that lay their eggs on specific seabed types) such as the surface of the herring, larval or juvenile ages, or species that live in contact seabed, including with the seabed like sandeel. Although disturbed, the abrasion (change to composition of sediments is unlikely to significantly change and seabed features) the habitat should be suitable for demersal spawning again once activities have been completed. The utilisation of HDD under the intertidal zone will minimise the amount of habitat disturbance during construction that is important for fish and shellfish species. Where possible, cable routing will avoid areas that are used by fish species that have substrate specific requirements, such as herring and sandeel. Transition elements Construction Whilst the increase in turbidity is not considered to be a and organo-metal potentially significant effect, the Medway Estuary is likely to be contamination polluted due to its historic activities. Indirect effects from the mobilisation of contaminants may affect the fish and shellfish ecology and may enter the food chain.
Underwater noise Construction Noise will be generated from project vessels including from changes dynamic positioning (DP) systems and during cable trenching, ploughing and rock placement operations. Noise will also be generated should any UXO detonations be required.
68 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Potential Effect Phase of Project Rationale for Inclusion
Displacement Construction The cable lay vessel will be slow moving and have a safety zone in placed around it during the construction of the Proposed Development. This may result in the temporary displacement of commercial fishing vessels to other fishing grounds during the construction phase.
10.6 Additional Baseline Information and Collection Methods Extensive information is available regarding fish and shellfish ecology of the southern North Sea. Therefore, no site-specific field survey is proposed. A desk-based assessment will be undertaken to determine the existing information with regards to the cable route and fisheries. Consultation will be undertaken with the following bodies as a minimum to ensure that that most up to date information is collated regarding the existing baseline environment: ▪ MMO; ▪ Cefas; ▪ Natural England; ▪ Joint Nature Conservation Committee; ▪ Environment Agency; ▪ Kent and Essex Inshore Fisheries and Conservation Authority; ▪ Collaborative Offshore Wind Research into the Environment (COWRIE). A baseline study to assess commercial fishing activity will be undertaken to understand the spatial and temporal distribution of fishing activity within this region. Relevant stakeholders will be consulted, including: ▪ Kent and Essex Inshore Fisheries and Conservation Authority (IFCA); ▪ Essex Shell Fishermen’s Association; ▪ Ramsgate Fishermen’s Association; ▪ Thanet Fishermen’s Association; ▪ Harwich Fishermen’s Association; and ▪ Rochester Oyster and Floating Fishery (ROFF). Interviews conducted with local and regional fishermen’s associations to obtain additional information on fishery statistics including fishing vessels operating in the area, types and sizes of vessels and fishing gear(s) used, fishing effort, target species and location of fishing grounds will also be undertaken to inform the baseline study. Collection of baseline data will focus on the most local and relevant ports to the Proposed Development, including Leigh-on-Sea, Whitstable, Herne Bay, Margate, Broadstairs, Ramsgate, Deal, Dover and Folkestone. Automatic Identification System (AIS) data from UK and European fishing vessels over 15 m in length and Voluntary Monitoring System (VMS) data from UK registered commercial fishing vessels over 12 m in length will also be obtained and interrogated to assess the
69 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
distribution of fishing effort. Aerial surveillance data gathered by the MMO will also be used to augment a qualitative assessment of the smaller fishing boats operating in the area. 10.7 Appraisal of Potential Effects Following collation of information on the baseline environment, an assessment of the effects on fisheries (including fish and shellfish ecology and commercial fisheries) in the vicinity of the Proposed Development will be undertaken. The assessment will also be undertaken using baseline data on commercial fishing activity. A risk- based assessment will be undertaken to identify any potentially significant impacts of the Proposed Development on commercial fisheries encompassing the Medway Estuary, Outer Thames Estuary, and southern North Sea. Effects will be determined based on a qualitative appraisal of the potential for sensitive receptors to be affected by the Proposed Development. The determination of significance will be based on expert judgement, taking into account factors such as sensitivity and vulnerability of receptors, duration of the activity being considered that gives rise to the effect, permanence of the effect and recoverability of the receptor. Measures to mitigate potentially significant effects will be proposed as appropriate.
70 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
11. HISTORIC ENVIRONMENT 11.1 Introduction This chapter describes the existing marine historic environment. It provides the rationale for excluding certain interactions from further consideration; and for those which are to be considered further, it explains the proposed approach to additional baseline characterisation and to the subsequent appraisal of the effects of the Proposed Development on those aspects of the historic environment. 11.2 Baseline Conditions The marine baseline can be characterised as comprising three fundamental categories: seabed prehistory, maritime archaeology and aviation archaeology. Source data for the marine baseline environment was assessed within a 2 km study area around the proposed cable route, delimited by the High Water Mark landward and the Median Line seaward. This data collection has been completed in line with Chartered Institute for Archaeologists (CIfA) standards of Desk Based Assessment42. Figures 11-1 to 11-9 below plot all known wrecks as held by the UK Hydrographic Office (UKHO) and all archaeological monuments as held by Historic England National Record of the Historic Environment (NRHE) Monument records, along the cable route.
11.2.1 Intertidal Archaeology No known archaeological/cultural heritage receptors in the intertidal zone are directly affected by the Proposed Development. However, the study area contains a number of known archaeological/cultural heritage receptors within 2 km. These include: ▪ Jetties and other structures associated with the now demolished Berry Wiggins Oil Refinery; ▪ Post-medieval sea walls around Oakham Ness; ▪ 17th Century battery on the southeast end of Oakham Ness ▪ Two Roman cremations, with associated Roman artefacts, together with a number of post- medieval enclosures and sea walls, as well as a probable saltern, to the north of Damhead Creek; ▪ Remains of German submarine UB-122, with a wooden barge Swale, located to the north of Damhead Creek, close to the hulk of a wooden barge, the Sophy; ▪ Five wrecks/hulks of unidentified craft to the south of Damhead Creek; ▪ A number of bomb craters dating to the Second World War identified by aerial photography analysis by English Heritage43.. The known archaeological/cultural heritage receptors are shown in Figure 11-1.
42 Chartered Institute for Archaeologists (CIfA), 2014, Standards and guidance for historic environment desk-based assessment, Reading, Chartered Institute for Archaeologists (http://www.archaeologists.net/sites/default/files/CIfAS&GDBA_2.pdf (accessed 30/01/2017) 43 Newsome, S, Carpenter, E and Kendall, P, 2015, The Hoo Peninsula Landscape Swindon, Historic England (https://content.historicengland.org.uk/images-books/publications/hoo-peninsula-landscape/hoo-peninsula-landscape.pdf/ (accessed 30/01/2017)
71 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Archaeological and Cultural Heritage Receptors Identified in the Intertidal Zone
72 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
11.2.2 Seabed Prehistory The potential for seabed prehistory in the Medway Estuary, Thames Estuary and southern North Sea is known to be high44. A high probability for Palaeolithic and Mesolithic submerged landscapes associated with the Palaeo-Medway and Palaeo-Thames river systems is also noted45, and there has been a high potential for prehistoric human and hominin exploitation of these landscapes for around 1 million years.
11.2.3 Maritime Archaeology Overall the UKHO records 270 wrecks or obstructions and the NRHE records 524 maritime archaeology receptors and known losses within 2 km of the proposed cable route, as summarised in Table 11-1. However, it should be noted that there is expected to be a degree of overlap between the two datasets for many of these receptors and losses. The UKHO and NRHE records of marine archaeological receptors are summarised by area in Table 11-2. The locations of recorded wrecks and other marine archaeological receptors are shown in Figure 11- 2 to Figure 11-6. Table 11-1 The details of the wrecks which are of particular interest (two of which are designated wrecks under the Protection of Wrecks Act) in the UKHO records are presented in Figures 11-7 to Figure 11-9.Known and Potential Marine Archaeological Receptors within 2 km of the Cable Route
UKHO NRHE
Dangerous wreck 126 Recorded loss 449 Non-dangerous wreck 6 Aircraft 24 Wreck showing any portion of hull or superstructure 55 Artefact 39 Foul ground 82 Feature 13 Diffuser 1 Other feature 112 TOTAL 382 524
Table 11-2 Known and Potential Marine Archaeological Receptors by Area
Area UKHO NRHE
Medway 116 329
Thames Estuary 218 125
Goodwin Sands 33 61
English Channel 15 9
Total 382 524
44 Bicket A and Tizzard L. (2015) A review of the submerged prehistory and palaeolandscapes of the British Isles. Proceedings of the Geologists’ Association 126, 643–663. 45 Wessex Archaeology (2013) Audit of Current State of Knowledge of Submerge Palaeolandscape and Sites, Salisbury, Wessex Archaeology (https://content.historicengland.org.uk/images-books/publications/audit-current-state-knowledge-submerged- palaeolandscapes- sites/84570-03_PalaeolandscapeAudit_01112013.pdf/ (accessed 30/01/2017)
73 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Archaeological and Cultural Heritage Receptors Identified in the Medway Estuary
74 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Archaeological and Cultural Heritage Receptors Identified in the Outer Thames Estuary Section 1
75 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Archaeological and Cultural Heritage Receptors Identified in the Outer Thames Estuary Section 2
76 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Archaeological and Cultural Heritage Receptors Identified in the Outer Thames Estuary Section 3
77 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Archaeological and Cultural Heritage Receptors Identified in the southern North Sea
78 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Potentially Important Wrecks and Aircraft Crashes in the Medway Estuary and Outer Thames Estuary
79 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Potentially Important Wrecks and Aircraft Crashes in the Outer Thames Estuary
80 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Potentially Important Wrecks and Aircraft Crashes in the southern North Sea
81 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
The cable route has been designed to ensure a minimum separation distance of 100 m from the location of known wrecks and other archaeological sites. In particular, the cable route has considered two key wrecks: ▪ The wreck of the SS Richard Montgomery (NRHE 904735 and UKHO 12800) is designated under section 2 of the Protection of Wrecks Act 197343. The wreck lies to the north of Sheerness and is a US freighter containing approximately 1400 tons of high explosives. The proposed cable route passes 1 km away from the position of the wreck. ▪ The battleship HMS Bulwark (NRHE 904919 and UKHO 12743, which exploded in the Medway in 1914 killing 736 on board, is designated under the Protection of Military Remains Act 1986 and has a 100 m radius exclusion zone. The proposed cable route passes 212 m to the south-east of the position of the wreck.
11.2.3.2 The River Medway and its Estuary The River Medway has the densest concentration of maritime archaeology with 116 UKHO records and 329 NRHE records. The recorded wreck site of HMS Princess Irene (NRHE 904923 and UKHO 12748), a converted minelayer that exploded in 1915 killing 350 people, lies 100 m north of the proposed cable route. The recorded wreck of the RN depot ship HMS Tyne (NRHE 904921 and UKHO 12746) which foundered close to the mouth of Damhead Creek, lies 300 m to the west of the proposed cable route. In addition, there are wrecks of at least eleven Royal Navy (RN) requisitioned drifters and trawlers from both wars within 2 km of the proposed cable route. The mouth of the Medway Estuary contains a concentration of early post-medieval recorded wrecks including eleven RN ships of the line, sloops and fireships sunk in the 1667 Battle of the Medway. At least six 17th, 18th and 19th Century RN wooden ships of the line sunk as breakwaters around Sheerness, including the 3rd Rates HMS Nottingham (NRHE 895125) and HMS Lenox (NRHE 1545831), and the 5th Rate HMS Aigle (NRHE 1256486), have also been recorded in the mouth of the Medway Estuary. All of these wrecks are of considerable significance. In the outer Medway Estuary, a group of seven wrecks on the Grain Flats, including the wooden English cargo vessel Katerine (NRHE 1445836), which sank in this area in 1320 with a cargo of iron, jewels and wine. This wreck will be of high significance as very few located wrecks of this period are known in UK waters.
11.2.3.3 The Thames Estuary The proposed cable route runs through the Outer Thames Estuary. This section contains 218 UKHO records and 125 NRHE records. The 1574 Gresham Ship (NRHE 1587680), was discovered during dredging in Princes Channel at the south-west end of Girdlers Sand by the Port of London Authority. Six wooden cargo vessels from the 1780s and 1790s that sank in the Thames Estuary, as well as the 1690 sloop Dragon that sank off North Foreland (NRHE 882633) and a 1345 wreck of a cargo ship carrying wine that sank off the Shivering Sands (NRHE 1447834) have been recorded. The remains of two Second World War RN Destroyers, HMS Blanche to the north of Margate (NRHE 904727 and UKHO 13972) and HMS Vimiera to the north of the Cant in the Medway Approach Channel (NRHE 904752 and UKHO 12820/12827) are within 2 km of the proposed cable route.
82 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
The wreck site of HMSM Truculent (UKHO 12853), a British submarine that sank after a collision in 1950, is also located within 2 km of the proposed cable route, although records show the wreck has been salvaged.
11.2.3.4 The Goodwin Sands The proposed cable route passes to the northeast and east of the Goodwin Sands. This navigation hazard to the east of Margate and Ramsgate off the Kent coast contains the densest concentration of recorded wrecks in UK waters, including a large number of post-medieval timber wrecks covered and uncovered by the shifting sands. Goodwin Sands contains 31 UKHO records and 61 NRHE records within 2 km of the proposed cable route. The location of these wrecks, as well as unrecorded wrecks, is often imprecise due to sediment movements within the Goodwin Sands.
11.2.3.5 The Southern North Sea 15 UKHO records and 9 NRHE recorded losses were identified within 2 km of the proposed cable route in the southern North Sea. These include the wrecks of two WWI German submarines sunk in 1915 (UC-7: UKHO 58795, U-37: NRHE 904860 and UKHO 13769.
11.2.4 Aviation Archaeology Twenty-four reported aircraft crashes have been recorded within 2 km of the proposed cable route, all of which are military, although the location of all of these is not known with any accuracy as the locations were often reported by witnesses located on land during the Second World War: ▪ Sheerness Point: 3 RAF Hawker Hurricanes, 1 RAF Handley Page Hampden bomber, 1 Messerschmidt 109 fighter, 1 Heinkel HE-111 bomber and 2 Junkers 88 bombers; ▪ Grain Flats: 1 Heinkel HE-111 bomber; ▪ Kingsnorth: 1 Supermarine Spitfire; ▪ Minster: 1 RAF Hawker Hurricane; ▪ Medway Approach Channel: 1 unidentified aircraft wreck; ▪ Margate Roads: 1 RAF Hawker Hurricane; and ▪ North Foreland: 4 RAF Supermarine Spitfires, 3 RAF Hawker Hurricanes, 1 RAF P-41 Mustang fighter, 1 RAF Armstrong Whitworth Whitley bomber, 1 RAF Short Stirling bomber and 1 RAF Vickers Wellington bomber. There is also potential for the discovery of previously unknown aircraft material dating from the early 1900s to the present day, especially for aircraft dating to the Second World War. This area saw significant aerial activity and associated losses occurred during the Second World War, due to its association with the Blitz raids on London. Furthermore, there is potential in the offshore areas of the proposed cable route in the Thames Estuary and southern North Sea, where aircraft crashes may not have been witnessed or reported46. All British RAF aircraft that crashed while in military service are automatically protected under the Protection of Military Remains Act 198647. 11.3 Mitigation Measures The proposed cable route has been delineated based on desk-top studies to maintain a distance of at least 100 m from any recorded wreck or other archaeological site. In addition, the cable will be
46 Wessex Archaeology, 2008, Aircraft Crashes at Sea. A Scoping Study. Salisbury, Wessex Archaeology (http://archaeologydataservice.ac.uk/catalogue//adsdata/arch-857- 1/dissemination/pdf/Aircraft_crash_sites_at_sea_final_Feb08.pdf – (accessed 30/01/2017) 47 Maritime & Coastguard Agency, Protected Wrecks designated under the Protection of Military Remains Act 1986 (https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/303274/Protected_wrecks_under_the_Pro tection_of_Milita ry_Remains_Act_86.pdf (accessed 30/01/2017)
83 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
micro-routed within the 500 m survey corridor following completion of the bathymetric, geophysical, geotechnical and environmental surveys to ensure that this separation is maintained from the actual surveyed extent of the site and any debris field. Any additional, specific Archaeological Exclusion Zones around significant known archaeological/cultural heritage receptors will also be observed by the cable route. Provision for mitigating adverse effects to unknown receptors will be aided by the implementation of a Protocol for Archaeological Discoveries (PAD). The PAD will provide a means for archaeological assessment of encountered chance-finds, sites and other material of interest and a mechanism to record, conserve and report on significant receptors if encountered during offshore survey, pre- construction, construction or maintenance of the Proposed Development. 11.4 Potential Effects to be Excluded from the EA None of the potential effects on historic environment are proposed to be excluded from the EA. 11.5 Potential Effects to be Included in the EA The potential effects on fisheries that are proposed to be included from the EA are defined in Table 11-3. Table 11-3 Effects on Fisheries to be Excluded from the EA
Potential Effect Phase of Project Rationale for Inclusion
Direct damage to Construction Although the proposed cable route has taken into account archaeological asset known archaeological sites, the precise location of many cultural heritage assets is not known so it is possible for previously unknown assets to be discovered during the construction phase of the Proposed Development.
Direct damage to Construction There is high potential for the Proposed Development to submerged prehistory interact with submerged prehistory and palaeolandscapes. and palaeolandscapes
Indirect damage to Construction External protection will be used to protect the cable in archaeological asset certain areas where burial is not possible. This may alter the hydrodynamic processes effecting sediment transport, which in turn may result in heritage assets becoming exposed.
11.6 Additional Baseline Information and Collection Methods An archaeological assessment of marine geophysical and geotechnical survey data will be undertaken by an appropriately qualified and experienced archaeological specialist, to identify any seabed features of potential marine archaeological interest.
84 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
11.7 Appraisal of Potential Effects The assessment of the effects of the Proposed Development on marine archaeological and cultural heritage assets will be conducted with reference to the relevant guidance, including COWRIE484950, JNAPC51 as well as technical guidance provided by Historic England52. Effects will be determined based on a qualitative appraisal of the potential for sensitive receptors to be affected by the Proposed Development, taking into account the scale and extent of the potential effect. The determination of significance will be based on expert judgement, taking into account factors such as sensitivity and vulnerability of receptors, duration of the activity being considered that gives rise to the effect, permanence of the effect and recoverability of the receptor. Measures to mitigate potentially significant effects will be proposed as appropriate.
48 Wessex Archaeology, 2007, Historic Environment Guidance for the Offshore Renewable Energy Sector. Salisbury, Wessex Archaeology (https://www.thecrownestate.co.uk/media/5876/km-ex-pc-historic-012007-historic-environment-guidance-for- the-offshore-renewable- energy-sector.pdf (accessed 31/01/2017) 49 Oxford Archaeology, 2007, Guidance for Assessment of Cumulative Impact on the Historic Environment from Offshore Renewable Energy. Commissioned by COWRIE Ltd (project reference CIARCH-11-2006) 50 Gribble J and Leather S for EMU Ltd, 2011, Offshore Geotechnical Investigations and Historic Environment Analysis: Guidance for the Renewable Energy Sector, Commissioned by COWRIE Project reference GEOARCH-09 (https://www.thecrownestate.co.uk/media/5901/km- ex-pc-historic-012011-offshore-geotechnical-investigations-and- historic-environment-analysis-guidance-for-the-renewable-energy- sector.pdf (accessed 31/01/2017) 51 JNAPC, 2006, JNAPC Code of Practice for Seabed Development, York, Joint Nautical Archaeology Policy Committee. (http://www.jnapc.org.uk/jnapc_brochure_may_2006.pdf (accessed 31/01/2017) 52 Plets R, Dix J and Bates R, 2013, Marine Geophysics Data Acquisition, Processing and Interpretation, English Heritage (https://content.historicengland.org.uk/images-books/publications/marine-geophysics-data-acquisition-processing- interpretation/MGDAPAI- guidance-notes.pdf/ (accessed 31/01/2017)
85 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
12. OTHER ENVIRONMENT ISSUES 12.1 Introduction The sections below provide the rationale for including or excluding certain effects on specific groups of environmental receptors from any further consideration within the EA. 12.2 Water Quality The nearest designated bathing waters are over 1.9 km from the proposed cable route at Sheerness. It is unlikely that localised increases in suspended solids as a result of the cable installation will breach any mandatory standards and no residual effects that are significant are predicted, as compliance with Directive 2006/7/EC of the European Parliament and of the Council of 15 February 2006 concerning the management of bathing water quality and repealing Directive 76/160/EEC (Bathing Waters Directive (2006/7/EC)) is determined based on potential faecal matter derived bacteria. Since the Proposed Development will not affect bacterial concentrations in seawater, the designated bathing waters are not considered to be a receptor of relevance and therefore they will not be considered further in the EA. The proposed cable route also passes through areas previously designated under Directive 2006/113/EC of the European Parliament and of the Council of 12 December 2006 on the quality required of shellfish waters (the Shellfish Water Directive (2006/113/EC) now repealed and subsumed under Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for the Community action in the field of water policy (The Water Framework Directive (WFD, 2000/60/EC), including Swalecliffe, Outer Thames and Margate areas. Shellfish Waters largely align with “shellfish harvesting areas” that are monitored by the Food Standards Agency for bacterial content only. Since the Proposed Development will not affect bacterial concentrations in seawater, the designated shellfish waters are not considered to be a receptor of relevance and therefore they will not be considered further in the EA. There is the potential for accidental fuel or oil spills from vessels during construction activities; however, all vessels operating as part of the Proposed Development will comply with the international requirements of the International Convention for the Prevention of Pollution from Ships 1973 (as amended) (MARPOL 73/78), as well as best practice for works in the marine environment, thereby minimising the risks of accidental spills. Leaching of materials from the Proposed Development is also highly unlikely given the use of modern cable armour and protection. Therefore, accidental spills will not be considered further in the EA. The horizontal directional drilling (HDD) for the landfall shore crossing will use industry standard barite based drilling fluids. As drilling reaches the predicted breakout point onto the seabed, the drilling fluids will be replaced with fresh water in order to minimise the release of any drill chemicals into the seabed or water column. As a result, the release of drill fluids into the seabed or water column is not expected to be significant and will not be considered further in the EA. However, in line with the requirements of a Marine Licence application, a Water Framework Directive (WFD) Screening Assessment will be undertaken to confirm that there are no significant effects on the waterbodies within 1 nm of the shore designated under the WFD and ensuring that the Proposed Development complies with the River Basin Management Plan. The WFD Assessment will follow the staged approach outlined in the Environment Agency guidance issued in December 2016. Hence, whilst water quality as a topic will not be considered as part of the EA, a WFD Assessment will be prepared as part of the documentation to support the Marine Licence application.
86 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
12.3 Shipping and Navigation The proposed cable route in the Medway Estuary passes the Port of Sheerness and Thamesport, as well as being located approximately 8 to 11 km from the municipal ports of Whitstable, Herne Bay, Margate, Broadstairs and Ramsgate. There are dense shipping routes and anchorages within the Thames Estuary that are located adjacent to the Proposed Development. The Proposed Development also crosses International Maritime Organisation (IMO) Dover Strait Traffic Separation Scheme (TSS) which handles vessel movements through the English Channel at the Strait of Dover. The proposed cable route also passes through the sea area controlled by the London Vessel Traffic Service (VTS). All vessels operating as part of the Proposed Development will adhere to International Regulations for Preventing Collisions at Sea 1972 (COLREGS), including displaying the lights and shapes required. Furthermore, Rule 10 of COLREGS requires that vessels crossing a traffic separation scheme must do so on a heading as near as practicable to right angles to the direction of traffic flow. Furthermore, during construction, safety information will be provided in accordance with the Maritime and Coastguard Agency (MCA) guidelines and through the United Kingdom Hydrographic Office who update nautical publications including Local and National Notice to Mariners. Safety information and notices will include a description of the activity and will be regularly updated to show accurate information on the current location of the construction activities and names of operating vessels, including guard vessels. The Kingfisher Information Service will also be notified with details of the works and final cable route published in their bulletins. The location of the cable following construction will also be marked on navigational charts to raise awareness of its presence to shipping and recreational craft in the area. In order to comply with the requirements of Marine Guidance Note 345, a Navigational Risk Assessment (NRA) will be undertaken. The NRA will provide a baseline study focussing on the key shipping routes and anchoring areas in the vicinity of the proposed cable route, and also consider commercial fishing activity. Consultation will be undertaken with relevant stakeholders including: ▪ Maritime Coastguard Agency (MCA); ▪ Trinity House Lighthouse Services; ▪ Dover Channel Navigation Information Service; ▪ London VTS; ▪ Port of London; ▪ Peel Ports; and ▪ Other port operators. The consultations will be used to agree the planned approach for the assessment and verify the desk- based data sources and fill in any information gaps. A burial risk assessment will be undertaken, taking into account the seabed sediment characteristics and external risks, to determine the optimal burial depths and additional protection measures required if deemed necessary. If cable protection by rock placement or concrete mattresses is used in areas where water depth is less than 30 m, there is the potential that chart datum could be reduced by more than 5%; the value recommended by the MCA as an acceptable change. The NRA will assess the implications on shipping and commercial fisheries of a change to water depth if necessary.
87 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
The potential effects of the Proposed Development on shipping and navigation will be considered by the NRA submitted as part of the documentation to support the Marine Licence application. The findings of the NRA will be summarised in the EA. 12.4 Third Party Infrastructure Infrastructure near the proposed cable route includes: a. Medway Approach Channel Disposal Site: closed, directly interacted; b. Garrison Point Disposal Site: closed, 160 m to the east; c. Medway Approach Channel B: disused, 225 m to the south; d. 11 active or in operation cables directly intersected (increasing to 13 for the alternative cable route); e. Five active cables within 250 m; and f. 16 decommissioned cables: directly intersected. Crossing and/or Proximity Agreements will be made with the operators of the infrastructure that are intersected by the Proposed Development in accordance with the requirements of The Crown Estate licence granted to GridLink. On this basis, no significant effects on the operation of existing infrastructure are anticipated and therefore this issue will not be considered as part of the EA. It should be noted that the effects of external protection used in the crossing of the infrastructure will be considered in the EA. 12.5 Other Marine Users Other sea users are likely to include recreational boating, recreational angling, marine aggregate extraction and offshore wind farms. However, the cable route has been designed to avoid crossings areas of known aggregate extraction and offshore wind farms. During the construction phase, a temporary safety zone will be put in place around the cable-laying spread which may result in some localised access restrictions for the duration of the cable-laying along that section of the route. However, the safety zone will be highly localised to the area of active working and limited in spatial extent as much as possible. The safety zone will move with the transit of the cable-lay spread at a nominal rate of 200-400 m per hour. On this basis, no significant environmental effects are anticipated and impacts on other marine users will not be considered as part of the EA. 12.6 Air Quality There are no air quality data available for the offshore environment, although local air quality is expected to be good. The North Sea is designated as an Emissions Control Area (ECA) under IMO International Convention for the Prevention of Pollution from ships (MARPOL) Annex VI (Regulations for the Prevention of Air Pollution from Ships). Since 1 January 2015, IMO MARPOL Annex VI requires that all vessels located inside of the ECA to use fuel with a sulphur content not exceeding 0.1% sulphur, or to employ an abatement technology that can be used to reduce SOx limits to a level that would be produced by the sulphur-in-fuels limit. Vessels operating during the construction or maintenance phases of the Proposed Development will adhere to this standard. On this basis, no significant environmental effects are anticipated on air quality and therefore this issue will not be considered as part of the EA.
88 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
13. SUMMARY 13.1 Scoping of Potential Effects of the Proposed Development Table 13-1 provides a summary of the effects of the Proposed Development that have been scoped in and out of the EA. Table 13-1 Summary of the Pressures to be Included Within the EA
Proposed Development Activity
d Sedimentsd and Seabe Processes Physical Ecology Benthic Coastal and Birds Marine MammalsMarine Fisheries Historic Environment
Water flow (tidal current) changes – local x - - - - - Wave exposure changes – local (i.e. changes to wave pattern from rock - - - - - berms) Penetration and/or disturbance of the substrate below the surface of the x x - - seabed, including abrasion (change to seabed features) Transition elements & organo-metal contamination - - - - Temperature changes – local - x - x x - Physical change (to another seabed type) - x - x - Changes in suspended solids (water clarity) - x - - x - Siltation rate changes, including smothering (depth of vertical sediment - x - - x - overburden) Electromagnetic changes - - - Underwater noise changes - - - - Visual disturbance - - x - - Displacement - - - - - Snagging hazard - - - - x - Direct damage to archaeological asset, submerged prehistory and/or - - - - - palaeolandscapes Indirect damage to archaeological asset - - - - - - No potential for interaction identified x Low potential interaction, to be excluded from EA Potential interaction, to be carried forward to EA. 13.2 EA Structure The structure proposed for the EA is as follows: i. Non-Technical Summary ii. Introduction iii. The Need for the Development and Project Alternatives
89 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
iv. Project Description v. Appraisal Methodology and Scope vi. Physical Environment a. Seabed Sediments and Physical Processes vii. Biological Environment a. Protected Sites for Nature Conservation b. Benthic Ecology c. Fish and Shellfish Ecology d. Marine and Coastal Birds e. Marine Mammals viii. Human Environment a. Commercial Fisheries b. Navigation Risk Assessment c. Historic Environment ix. Cumulative Effects Assessment x. Summary of Mitigation Measures xi. Conclusions Additional documents that will be prepared to support the EA and also accompany the Marine Licence application will comprise: 1. Water Framework Directive Screening Assessment; 2. Habitat Regulations Assessment Screening; 3. Marine Conservation Zone Assessment; and 4. Navigational Risk Assessment. 13.3 Impact Assessment Methodology The EA will cover all phases of the Proposed Development including construction, operation and maintenance/repair. The EA will be prepared in accordance with the following guidance documents: ▪ The Institute of Environmental Management and Assessment (IEMA) Environmental Impact Assessment Guide to: Delivering Quality Development, 2016 ▪ The Institute of Environmental Management and Assessment (IEMA) Guidelines for Environmental Impact Assessment, 2004 ▪ The Chartered Institute of Ecology and Environmental Management (CIEEM) Guidelines for Ecological Impact Assessment in Britain and Ireland: Marine and Coastal, 2010; and ▪ Scottish Natural Heritage (SNH), A handbook on environmental impact assessment: Guidance for Competent Authorities, Consultees and others involved in the Environmental Impact Assessment (EIA) Process in Scotland, 2013. [This guidance is also relevant to EA in other parts of the UK].
90 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
The assessment process will involve the following steps:
The steps are described in more detail below.
13.3.1 Characterisation of the existing baseline In order to assess the potential pressures resulting from the project it is necessary to first establish the physical, biological, and human conditions that currently exist along and within the vicinity of the proposed cable route. A good understanding of the baseline for each environmental receptor will be achieved through four activities: ▪ Review of primary baseline studies (field). ▪ Review of additional specialist baseline studies (desk-based). ▪ Detailed review of all secondary sources (i.e. existing documentation and literature). ▪ Stakeholder consultation. The key data sources used to establish the baseline. For each receptor, the baseline will be described in sequence following the proposed cable route from the landfall to the median line.
13.3.2 Establish potential pressures and zone of influence For each pressure identified in this Scoping report as to be taken forward for assessment in the EA the zone of influence – the spatial extent over which the activities are predicted to have an effect on the receiving environment will be established. This will vary for different activities and for the different stages of the project (cable installation, operation and maintenance/repair). Establishing the zone of influence for different pressures and receptors will be undertaken quantitatively wherever possible, but also qualitatively where necessary based on the project description, project experience and literature reviews. Zones of influence will be established in the project description.
91 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Where a number of project activities have the same pressures (e.g. pre-sweeping, pre-lay grapnel run, trenching, etc that all result in seabed disturbance) or the installation technique has not been determined, the worst-case spatial extent will be applied.
13.3.3 Characterisation of the change and effect In order to fully characterise an effect or level of change from baseline conditions the scale of change, spatial extent and duration / frequency of the change will be considered. These parameters are used to define the magnitude of change or the magnitude value for the impact based on the definitions provided in Table 13-2. Table 13-2 Criteria for characterising the magnitude of the impact
Magnitude Definition Value High Long term (> 5 years) and/or regional level loss or major alteration to key elements /features of the baseline condition, such that post development character/composition of baseline will be fundamentally changed. Medium Medium term (1- 5 years) loss and/or local level change (greater than the project footprint) or alteration to one or more key elements/features of the baseline conditions, such that post development character/composition of the baseline condition will be materially changed. Low Short term (<1 year), site specific and/or minor shift away from baseline conditions. Changes arising from the alteration will be detectable but not material, such that the underlying character /composition of the baseline condition will be similar to the pre-development situation. Negligible Very little change from baseline conditions. Change is barely distinguishable, approximating to a “no change” situation.
13.3.4 Characterisation of the receptor The significance of an effect on a receptor or feature is characterised by the sensitivity, recoverability and importance of the receptor or feature. Characterisation of the receptor is achieved by balancing these three considerations to determine the ‘Receptor Value’. Criteria to be used for the assessment are presented in Table 13-3.
92 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Table 13-3 Criteria for characterising the sensitivity of the receptor (receptor value)
Receptor Definition Value High Receptor has little or no ability to absorb change without fundamentally altering its character. For example: Physical Biological Human One or more combinations of: One or more combinations of: One or more combinations of: ▪ Receptor has low / no capacity ▪ Receptor has low tolerance to ▪ Receptor has low / no capacity to return to baseline condition change e.g. the species population to return to baseline e.g. low within project life e.g. low is likely to be killed or destroyed by tolerance to change and low tolerance to change and low the project activity (MarLin 2016). recoverability such as loss of recoverability such as a access with no alternatives. ▪ Recovery to baseline conditions physical feature formed over a over a very long period i.e. > 10 ▪ Damage to asset(s) e.g. at geological time scale. years or not at all (MarLin 2010). cable crossing, resulting in ▪ The receptor is a designated major financial consequences ▪ The receptor is a designating feature of a protected site, or for the company. feature of an International is rare or unique. protected site e.g. European ▪ Receptor is economically Natura 2000 or RAMSAR site valuable. ▪ Receptor is very rare / unique / or ecologically important.
Medium Receptor has moderate capacity to absorb change without significantly altering its character; however some damage to the receptor will occur. For example: Physical Biological Human One or more combinations of: One or more combinations of: One or more combinations of: ▪ Receptor has intermediate ▪ Receptor has intermediate ▪ Receptor has intermediate tolerance to change. tolerance to change e.g. some tolerance to change e.g. loss individuals of the species may be of access but acceptable ▪ Medium capacity to return to killed/destroyed by the project alternatives, alteration to baseline condition e.g. >5 of activity and the viability of a route but with no significant up to 10 years. species population may be reduced economic consequences. ▪ The receptor is valued but not (MarLin 2016). ▪ Damage to asset(s) e.g. at protected. ▪ Recovery to baseline conditions cable crossings, resulting in over a long period i.e. > 5 or up to financial consequences for the 10 years (MarLIN 2010). company. ▪ The receptor is designated as a national site e.g. NHA ▪ Uncommon or moderately valuable economically or ecologically but not rare or unique.
Low The receptor is tolerant to change without significant detriment to its character. Some minor damage to the receptor may occur. For example:
Physical Biological Human One or more combinations of: One or more combinations of: One or more combinations of: ▪ Noticeable but short-term, ▪ Localised or short term damage / ▪ May affect behaviour but is localised change in baseline disturbance to portion of the not a nuisance to users. condition e.g. within population / habitat ▪ Minor / no financial environmental quality ▪ Recovery to baseline conditions consequence to the company. standards or regulatory within 1 year compliance levels, disturbance to seabed sediments, seabed ▪ The receptor is neither rare,
93 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
Receptor Definition Value features, geomorphological unique or of significance in terms features, coastal processes or of economic or ecological value. quality change within zone of
influence. ▪ High capacity to return to baseline condition e.g. <1 year ▪ The receptor is common and/or widespread.
Negligible The receptor is tolerant to change with no effect on its character. The project activity does not have a detectable effect on survival or viability of a species (MarLIN 2016). The habitat or species is expected to recover rapidly i.e. within a week (MarLIN 2010)
13.3.5 Assessment of significance of effect Having established the magnitude of change (magnitude value) and the sensitivity of the receptor (receptor value), the significance of the effect will be assessed using the significance matrix adapted from the SNH (2003) Handbook on EIA, as presented in Table 13-4. Table 13-4 Significance matrix
Magnitude of change
Negligible Low Medium High
High Negligible Moderate Major Major
Medium Negligible Minor Moderate Major
Low Negligible Negligible Minor Moderate
Negligible Negligible Negligible Negligible Minor Sensitivity of Sensitivity receptor
The result of using this matrix approach is the assignment of the level of significance of the effect for all project potential pressures. This is done prior to any mitigation. Definitions of the significance levels are provided in Table 13-5 below. Table 13-5 Definitions of significance levels
Significance Definition Negligible Generally considered as insignificant. Minor Generally considered as insignificant and adequately controlled by best practice and legal controls. Opportunities to reduce effects further through mitigation may be limited and are unlikely to be cost effective. Moderate Generally effects are those people are prepared to tolerate. However, it is expected that the residual effect has been subject to feasible and cost effective mitigation, and has been reduced to as low as reasonably practicable (ALARP) and that no further measures are feasible. Major Generally regarded as unacceptable prior to any mitigation measures being considered.
94 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
The significance assessment is repeated taking into consideration the application of legal compliance and appropriate mitigation. This determines whether there is likely to be a residual impact. When applied after mitigation, the resulting significance level is referred to as the residual significant effect. Residual effects assessed as moderate or major after consideration of proposed mitigation measures will be subject to additional analysis and consultation in order to further mitigate impacts where possible. Where further mitigation is not possible, the residual effect will be specified.
13.3.6 Establishment of mitigation Mitigation measures are the actions or systems proposed to manage or reduce the potential negative impacts that are identified. Mitigation measures are sometimes confused with measures taken to ensure legal compliance, which can be similar. Legislation is often designed to ensure impacts to the environment are minimised. Legal compliance can therefore avoid or abate negative impacts. Measures which are considered legal compliance will be listed as appropriate. Typically, mitigation measures are applied following the hierarchy below: ▪ Avoid or Prevent: In the first instance, mitigation should seek to avoid or prevent the adverse effect at source for example, by routing the cables away from a sensitive receptor. ▪ Reduce: If the effect is unavoidable, mitigation measures should be implemented which seek to reduce the significance of the effect. ▪ Offset: If the effect can neither be avoided nor reduced, mitigation should seek to offset the effect through the implementation of compensatory mitigation. Mitigation measures fall into two categories: mitigation which forms part of the project design; and mitigation which is part of the construction and operation of the project. Mitigation measures which form part of the design are an inherent part of the project and are considered the ‘base case’. Mitigation measures which are to be adopted and implemented during the construction and operation of the project are measures put in place to mitigate adverse effects, over and above legal compliance. Appropriate, feasible and cost-effective mitigation measures will be specified as part of the assessment.
13.3.7 Assessment of significance of residual effect For those potential pressures which are determined to require project-specific mitigation measures, a further assessment will be made to determine if, after the application of the specified mitigation measures, any residual effects will remain. The assessment process described above will be repeated to determine the significance of any residual effects. 13.4 Cumulative Effects Assessment The EA will assess cumulative and indirect impacts and interactions. For the purposes of the assessment, the definitions proposed by the European Commission (1999) will be used. The definitions are as follows: ▪ Indirect Impacts (secondary impacts) – 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. ▪ Cumulative Impacts – Impacts that result from incremental changes caused by other past, present or reasonably foreseeable actions together with the project.
95 P2114_R4493_Rev2 | 16 August 2018
GridLink Interconnector Scoping Report for a Marine Environmental Appraisal
▪ Impact Interactions – The reactions between impacts whether between the impacts of just one project or between the impacts of other projects in the area. For the purposes of the EA, the potential impacts of the development are considered in terms of impacts on each of the discrete environmental subjects. In reality, subjects such as ‘water quality’ or ‘ecology’ cannot always be considered in isolation since changes affecting one factor may often have secondary implications for other areas. Thus, if one impact of the development is to alter the quality of a watercourse, flora and fauna may be affected as a secondary effect. The EA will identify and assess potential indirect or cumulative impacts and interactions between environmental subjects. The assessment of cumulative impacts will consider other projects that have been granted development consent. In-combination effects is a term used specifically in relation to the Habitats Regulation Appraisal which requires effects of a project to be assessed alone and ‘in-combination’ with other plans or projects. An in-combination assessment will be included within the HRA and MCZ assessments. The projects to be considered in the cumulative effects assessment and in-combination will be agreed with the MMO prior to commencement of the assessment.
96 P2114_R4493_Rev2 | 16 August 2018