PHASE ONE

DraFt EnvironmEntal StatEmEnt Community Forum Area Report 6 | South Ruislip to Ickenham HS2 London-West Midlands May 2013

ENGINE FOR GROWTH DRAFT ENVIRONMENTAL STATEMENT Community Forum Area Report ENGINE FOR GROWTH 6 I South Ruislip to Ickenham High Speed Two (HS2) Limited, 2nd Floor, Eland House, Bressenden Place, London SW1E 5DU

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Printed in Great Britain on paper containing at least 75% recycled fibre. CFA Report – South Ruislip to Ickenham/No 6 I Contents Contents

Draft Volume 2: Community Forum Area Report – South Ruislip to Ickenham/No 6 5 Part A: Introduction 6 1 Introduction 7 1.1 Introduction to HS2 7 1.2 Purpose of this report 7 1.3 Structure of this report 9 Part B: South Ruislip to Ickenham – overview of the area and description of the Proposed Scheme 10 2 South Ruislip to Ickenham 11 2.1 Overview of the area 11 2.2 Description of the Proposed Scheme 15 2.3 Construction of the Proposed Scheme 17 2.4 Operation of the Proposed Scheme 28 2.5 Community forum engagement 29 2.6 Route section main alternatives 29 2.7 Proposals for further consideration 34 Part C: Environmental topic assessments 35 3 Agriculture, forestry and soils 36 3.1 Introduction 36 3.2 Policy framework 36 3.3 Assessment scope and key assumptions 36 3.4 Environmental baseline 36 3.5 Construction 37 3.6 Operation 38

1 CFA Report – South Ruislip to Ickenham/No 6 I Contents

4 Air quality 39 4.1 Introduction 39 4.2 Policy framework 39 4.3 Assessment scope and key assumptions 39 4.4 Environmental baseline 39 4.5 Construction 40 4.6 Operation 41 5 Community 42 5.1 Introduction 42 5.2 Policy framework 42 5.3 Assessment scope and key assumptions 42 5.4 Environmental baseline 42 5.5 Construction 44 5.6 Operation 45 6 Cultural heritage 47 6.1 Introduction 47 6.2 Policy framework 47 6.3 Assessment scope and key assumptions 47 6.4 Environmental baseline 47 6.5 Construction 48 6.6 Operation 50 7 Ecology 51 7.1 Introduction 51 7.2 Policy framework 51 7.3 Assessment scope and key assumptions 51 7.4 Environmental baseline 52 7.5 Construction 54 7.6 Operation 57 8 Land quality 58 8.1 Introduction 58 8.2 Policy framework 58 8.3 Assessment scope and key assumptions 58 8.4 Environmental baseline 58 8.5 Construction 60 8.6 Operation 62

2 CFA Report – South Ruislip to Ickenham/No 6 I Contents

9 Landscape and visual assessment 64 9.1 Introduction 64 9.2 Policy framework 64 9.3 Assessment scope and key assumptions 64 9.4 Environmental baseline 65 9.5 Construction 66 9.6 Operation 69 10 Socio-economics 73 10.1 Introduction 73 10.2 Policy framework 73 10.3 Assessment scope and key assumptions 73 10.4 Environmental baseline 73 10.5 Construction 74 10.6 Operation 76 11 Sound, noise and vibration 77 11.1 Introduction 77 11.2 Policy framework 77 11.3 Assessment scope and key assumptions 77 11.4 Environmental baseline 78 11.5 Construction 78 11.6 Operation 79 12 Traffic and transport 82 12.1 Introduction 82 12.2 Policy framework 82 12.3 Assessment scope and key assumptions 82 12.4 Environmental baseline 83 12.5 Construction 85 12.6 Operation 88 13 Water resources and flood risk assessment 89 13.1 Introduction 89 13.2 Policy framework 89 13.3 Assessment scope and key assumptions 89 13.4 Environmental baseline 90 13.5 Construction 91 13.6 Operation 94 14 References 96

2 3 CFA Report – South Ruislip to Ickenham/No 6 I Contents

List of figures

Figure 1: HS2 Phase One route and community forum areas 8 Figure 2: Area context map 12 Figure 3: Indicative construction programme for the area 28 Figure 4: Business Sector Composition in LBH and London 74

List of tables

Table 1: Location of construction site compounds, 18 Table 2: Demolition works 21 Table 3: Footpath, cycleway and bridleway diversions 24 Table 4: Holdings that would be affected by the Proposed Scheme 37 Table 5: Preliminary evaluation of likely value of protected and/or notable species occurring within this study area 53 Table 6: Significant residual construction effects on ecological receptors within the study area 56 Table 7: Significant residual operational effects on ecological receptors within this study area 57 Table 8: Significant landscape effects during construction 67 Table 9: Significant visual effects during construction 68 Table 10: Significant landscape effects during operation year 1 (2026) 70 Table 11: Significant visual effects during operation year 1 (2026) 71 Table 12: Options for further mitigation 81 Table 13: Typical vehicle trip generation for site compounds in this area 85

4 CFA Report – South Ruislip to Ickenham/No 6 I Contents Draft Volume 2: Community Forum Area Report South Ruislip to Ickenham/No 6 Structure of the HS2 draft Environmental Statement The draft ES documentation for the purpose of this consultation comprises: • A non-technical summary (NTS) – providing a summary of the Proposed Scheme, the likely significant effects of the Proposed Scheme, both beneficial and adverse, and the means to avoid or reduce the adverse effects; • A main report – consisting of two volumes: ȃȃ Volume 1: Introduction to the Environmental Statement and Proposed Scheme which provides an introduction to HS2, an overview of the hybrid bill process and the environmental impact assessment (EIA) methodology, an introduction to consultation and engagement, the main strategic and route-wide alternatives considered; and ȃȃ Volume 2: Includes 26 Community Forum Area (CFA) reports, each with a separate corresponding set of drawings, which together provide the assessment of local environmental effects. An assessment of the effects of the Proposed Scheme on a route-wide basis is presented in Report 27.

HS2 Ltd set up 26 community forums along the line of route of the Proposed Scheme, as a regular way of engaging with local communities1. Volume 2 of this draft ES supports this engagement strategy by providing a draft ES report for each CFA. This is a report for the South Ruislip to Ickenham area, CFA6.

The draft ES has been written in a clear and accessible manner; however, on occasion it has been necessary to use technical terms. Given this, a glossary of terms and list of abbreviations for all draft ES documentation is provided.

1 Details of these community forums are provided on the HS2 Ltd website at http://www.hs2.org.uk/have-your-say/forums/community-forums.

5 CFA Report – South Ruislip to Ickenham/No 6 I Contents Part A: Introduction

6 CFA Report – South Ruislip to Ickenham/No 6 I Introduction 1 Introduction 1.1 Introduction to HS2 1.1.1 HS2 is planned to be a Y-shaped rail network with stations in London, Birmingham, Leeds, Manchester, South Yorkshire and the East Midlands, linked by high speed trains running at speeds of up to 360 kilometres per hour (kph) (225 miles per hour (mph)).

1.1.2 HS2 is proposed to be built in two phases. Phase One (the Proposed Scheme), the subject of this draft ES, would involve the construction of a new railway line of approximately 230km (143 miles) between London and Birmingham that would become operational by 2026, with a connection to the West Coast Main Line (WCML) near Lichfield and to the existing HS1 line in London. The Phase One route and the 26 CFAs are shown in Figure 1.

1.1.3 On opening, Phase One would run up to 14 trains per hour (tph). HS2 trains would be up to 400 metres (m) long with 1,100 seats during peak hours. Beyond the dedicated high speed track, these high speed trains would connect with and run on the existing WCML to serve passengers beyond the HS2 network. A connection to HS1 would also allow some services to run to mainland Europe via the Channel Tunnel.

1.1.4 Phase Two would involve the construction of lines from Birmingham to Leeds and Manchester; with construction commencing around 2027, and planned to be operational by 2033. After Phase Two opens, it is expected that the frequency of train services on some parts of the Phase One route could increase up to 18tph.

1.1.5 The Government believes that the HS2 network should link to Heathrow and its preferred option is for this to be built as part of Phase Two. However, the Government has since taken the decision to pause work on the Heathrow link until after 2015, when it expects the Airports Commission to publish its final report on recommended options for maintaining the country’s status as an international aviation hub. 1.2 Purpose of this report 1.2.1 This report presents the likely significant environmental effects as a result of the construction and operation of the Proposed Scheme that have been identified to date within the area of South Ruislip to Ickenham (CFA6). It provides a summary of the likely environmental issues and proposed mitigation measures that are being addressed during the design development process within the South Ruislip to Ickenham area.

1.2.2 The final details of the Proposed Scheme and assessment of its environmental impacts and effects will be presented in the formal ES submitted in accordance with the requirements of Parliamentary Standing Order 27A (SO27A)2.

2 Standing Order 27A of the Standing Orders of the House of Commons relating to private business (environmental assessment), House of Commons.

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Figure 1: HS2 Phase One route and community forum areas

8 CFA Report – South Ruislip to Ickenham/No 6 I Introduction

1.3 Structure of this report 1.3.1 This report is divided into three parts: • Part A – an introduction to HS2 and the purpose of this report; • Part B – overview of the area, description of the Proposed Scheme within South Ruislip to Ickenham and its construction, community forum engagement, and a description of the main local alternatives; and • Part C – environmental topic assessments – overview of the policy framework, the environmental baseline within the area, an assessment of construction and operational effects, the proposed mitigation measures, and significant residual effects for the following environmental topics: ȃȃ Agriculture, forestry and soils; ȃȃ Air quality; ȃȃ Community; ȃȃ Cultural heritage; ȃȃ Ecology; ȃȃ Land quality; ȃȃ Landscape and visual assessment; ȃȃ Socio-economics; ȃȃ Sound, noise and vibration; ȃȃ Traffic and transport; and ȃȃ Water resources and flood risk.

1.3.2 The maps relevant to South Ruislip to Ickenham are provided in a separate corresponding document entitled Volume 2: CFA6 Maps, which should be read in conjunction with this report.

1.3.3 In addition to the environmental topics covered in Part C of this report, Report 27 also addresses climate, electromagnetic interference and waste and material resources on a route- wide basis.

9 CFA Report – South Ruislip to Ickenham/No 6 I Introduction Part B: South Ruislip to Ickenham – overview of the area and description of the Proposed Scheme

10 CFA Report – South Ruislip to Ickenham/No 6 I South Ruislip to Ickenham 2 South Ruislip to Ickenham 2.1 Overview of the area 2.1.1 The South Ruislip to Ickenham CFA covers a 6.7km section of the Proposed Scheme in the London Borough of Hillingdon (LBH). The route extends from a point to the south of Rabournmead Drive in the east to Harvil Road in the west (see maps CT‑01-07 to CT‑01-09).

2.1.2 As shown in Figure 2, Northolt Corridor (CFA5) lies to the east and Colne Valley (CFA7) lies to the west. Settlement, land use and topography

2.1.3 The area is predominantly suburban in character in the east and becomes more rural in character north and north-west of Ickenham. The area has a mixed land use pattern of residential properties, industry, open space, farmland and road and rail links. The route would pass to the south of South Ruislip and Ruislip Manor and to the north of Ruislip Gardens and Ickenham (see CT‑01-07 to CT‑01-09).

2.1.4 The area is located in a part of London that remained rural in character until the early 20th century, when a number of Royal Air Force (RAF) bases and aerodromes were constructed (between 1915 and 1920). Following the development of the railway network, the area saw steady inter-war suburban development, including the construction of residential estates at Ruislip Gardens and Ruislip Manor.

2.1.5 South Ruislip and Ruislip Manor are divided by Yeading Brook and comprise large areas of terraced housing with some light industry on Victoria Road. The majority of the Ruislip Gardens area is occupied by RAF Northolt and Northolt Aerodrome. Ickenham mainly comprises inter-war housing with wide streets.

2.1.6 The eastern and western arms of Yeading Brook flow in a north to south direction through the area and cross the route in the vicinity of Victoria Road/Civic Way and to the west of Ruislip Gardens Station respectively. The River Pinn also flows in a north to south direction through the area and crosses the route to the east of the Breakspear Road South. The Newyears Green Bourne stream crosses Harvil Road at the western end of this section of the Proposed Scheme. Water features are shown on map CT‑04-05.

2.1.7 The topography of the Ruislip and Ickenham area is generally flat with a small rise and fall between Breakspear Road South and Harvil Road at the western end of this section of the route.

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Figure 2: Area context map

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Key transport infrastructure

2.1.8 The Marylebone to Aylesbury Line runs through the area in an east to west direction. The London Underground Central Line runs in an east to west direction parallel to the alignment of the Marylebone to Aylesbury Line, between the boundary of CFA5 (south of Rabournmead Drive) and West Ruislip Station which is the western terminus of the Central Line. The London Underground Metropolitan and Piccadilly Lines also run north-south through the area crossing the route to the east of Ickenham Road.

2.1.9 South Ruislip, Ruislip Gardens and West Ruislip London Underground stations and South Ruislip and West Ruislip Network Rail stations are located in the area. Ruislip Rail Depot is located between Ruislip Gardens and West Ruislip stations.

2.1.10 RAF Northolt and Northolt Aerodrome are located to the south of the route and accommodate both military and civilian private aircraft.

2.1.11 Western Avenue (A40) runs in an east to west direction through the area to the south of the route. In addition, West End Road (A4180) runs in a north-west to south-east direction through the area and crosses the route at Ruislip Gardens. Ickenham Road/Long Lane (A437/B466) runs in a north to south direction through the area and cross the route at West Ruislip.

2.1.12 The key transport infrastructure is shown on map CT‑02-05. Demographic profile

2.1.13 The resident population within 500m of the centre line of the route is estimated to be approximately 16,000. The population is expected to increase 35% in this area by 2035.

2.1.14 There is a moderate level of ethnic diversity in the population with 24% consisting of non- white ethnic groups.

2.1.15 The majority of people (68%) are of working age (16-64), although this is lower than most outer London boroughs.

2.1.16 The employment rate in the area is 74%. This is higher than the rate for Hillingdon (65%) and England (65%).

2.1.17 Most of the housing stock in the area is owner-occupied or privately rented (94%)3. Notable community facilities

2.1.18 The main shops and services are located on Civic Way, Stonefield Way and also Ruislip High Street, which is located just outside the study area. In addition, neighbourhood shops are located throughout the residential parts of the area. There are no community centres or halls in the area. However, Blenheim Day Care Centre is located on Ickenham Road. The area includes one church, the South Ruislip Christian Fellowship Centre, approximately 250m from the proposed route on Deane Avenue.

2.1.19 Educational facilities in the area include three early-years educational facilities, five primary schools and three secondary schools. West London Tutorial College is located in Hill Rise. There are two doctor’s surgeries and one dental practice in the area.

2.1.20 Numerous bridges over the existing Marylebone to Aylesbury Line and London Underground Central Line provide important community links between the residential areas to the north and south of the route.

3 Office for National Statistics (2012), Census 2011, http://www.ons.gov.uk/ons/guide-method/census/2011/index.html; Accessed: 1 February 2013.

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Recreation, leisure and open space

2.1.21 There are a wide range of sports and recreational facilities in the area. These include: three football grounds/clubs; a branch of the Sea Cadets; two sports and social clubs; a golf course; a rifle club; and a fitness centre. Informal recreational space is provided by open space to the south of Ruislip High School and Ickenham Green. Playgrounds are located throughout the residential areas.

2.1.22 Public rights of way (PRoW) are mainly limited to the area around the Ruislip Golf Course. There is one existing PRoW which crosses the route from north to south across the Ruislip Golf Course and adjacent to the canal feeder (also known locally as the Ickenham Stream).

2.1.23 The principal open spaces in the vicinity of the Proposed Scheme comprise: Ruislip Golf Course; King George V Playing Fields/Ickenham Green; Ickenham Marshes Complex (to the northwest of RAF Northolt); and Islip Manor Local Nature Reserve (LNR), which lies just beyond the eastern boundary of this section of the Proposed Scheme in the Northolt Corridor (CFA 5). Some of these areas have ecological designations which are discussed in more detail in Section 7 Ecology. Planning context and key designations

2.1.24 Volume 1 sets out the national policies under which HS2 has been developed. Given that the Proposed Scheme has been developed on a national basis and to meet a national need, it is not included or referred to in many local or regional plans. Nevertheless, in seeking to consider the Proposed Scheme in the local context, relevant local plan documents and policies have been taken into account in relation to environmental topics.

2.1.25 The London Plan is the overall strategic plan for London. It sets out a fully integrated economic, environmental, transport and social framework for the development of the capital to 20314. London boroughs’ Local Development Frameworks need to be in general conformity with the London Plan, and its policies guide decisions on planning applications by councils and the Mayor.

2.1.26 The CFA6 area falls within the administration of the LBH where local policies apply. This includes the adopted Hillingdon Local Plan Part 1, (2012) and Saved Unitary Development Plan (UDP) policies (2007) – Hillingdon Local Plan: Part 2, which make up the Local Development Framework (LDF) for the borough5,6,7.

2.1.27 Relevant policies from these documents have been taken into account in relation to technical assessments reported in Sections 3 to 13.

2.1.28 Emerging policies are not considered in this report. However, it should be noted that during 2013 the LBH intends to prepare and consult on various components of Part 2 of the Hillingdon Local Plan, which will consist of the Development Management Policies, Site- Specific Allocations and an associated Policies Map. However there are no firm timeframes provided for these emerging policy documents.

2.1.29 There are a number of key planning designations in the area: • The A40 and M4 corridors to the south of the route have been designated an Air Quality Management Area (AQMA) by LBH on the basis of the widespread nature of elevated nitrogen dioxide (NO2) concentrations (maps CT‑02-05);

4 GLA (2011), The London Plan: Spatial Development Strategy for Greater London. 5 LBH (2012), Adopted Hillingdon Local Plan Part 1. 6 LBH (2007), Saved Unitary Development Plan policies, Hillingdon Local Plan: Part 2. 7 LBH (1998), Adopted Unitary Development Plan Saved Policies (now Hillingdon Local Plan Part 2).

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• The route runs through or is adjacent to areas of designated green belt which lie to the north and south of the Proposed Scheme and includes various open and green spaces, such as Ruislip Gardens Recreational Grounds, New Pond Playing Field, South Ruislip Farmland, Ickenham Green Ickenham Cricket Club Ground, King George V Playing Field, Mad Field Covert, and Ruislip Gardens Farmland; • There are three designated conservation areas: Ickenham Village, Ruislip Village; and Ruislip Manor Way; • Nationally designated buildings and structures include two scheduled monuments and seven Grade II listed buildings. These are discussed in more detail in Section 7 Cultural Heritage (maps CT‑01-07 to CT‑01-09); and • Ruislip Woods National Nature Reserve; Ruislip Golf Course and Old Priory Meadows Site of

Borough Importance Grade I (SBII); Newyears Green SBII; and Brackenbury Railway Cutting

Grade II (SBIII) (maps CT‑01-07 to CT‑01-09). 2.2 Description of the Proposed Scheme 2.2.1 The general design of the Proposed Scheme is described in Volume 1. The following section describes the main features of the Proposed Scheme in the South Ruislip to Ickenham area, including the main environmental mitigation measures. Overview

2.2.2 The Proposed Scheme would commence at the boundary with Northolt Corridor (CFA5) directly south of Rabournmead Drive, South Ruislip. It would then proceed north-west in tunnel for 4.4km at a depth of approximately 30m below ground level.

2.2.3 A tunnel portal would be constructed in West Ruislip, approximately 70m west of Ickenham Road. After gradually returning to the surface on a ramp within the portal structure, the route would be on embankment with bridges across the River Pinn and Breakspear Road South. West of Breakspear Road South the route would initially be on embankment and then in cutting which would extend to the boundary with the Colne Valley (CFA7) at Harvil Road, Ickenham. Sidings to facilitate construction works would be provided between Breakspear Road South and Harvil Road. A ventilation and intervention shaft (vent shaft) would be located at South Ruislip. Key features of the Proposed Scheme are shown on maps CT‑06-014 to CT‑06-018.

2.2.4 Since the January 2012 scheme was announced by the Secretary of State, route development work has continued, and the route now differs in some respects, i.e.: • The tunnel entrance is located further west from Ickenham Road; • The realignment of Harvil Road; and • There is passive provision for a rail link to Heathrow Airport.

2.2.5 Design development continues on this section of route. Any further changes resulting from this would be assessed in the formal ES if accepted into the Proposed Scheme. Proposed Scheme – Section by section

2.2.6 From the boundary with the Northolt section of the Proposed Scheme in the south-east the route would be in tunnel for 4.4km between South Ruislip and West Ruislip. Key design features of this section (see maps CT‑06-014 to CT‑06-016) would include: • Twin bored tunnels of 8.8m internal diameter with connecting cross passages at regular intervals at a depth of approximately 30m below ground level;

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• A rectangular box shaft to a depth of 30m below ground level at South Ruislip on an unoccupied industrial site (former Arla Dairy, see map CT‑06-015) and a connection to the running tunnels by adits (horizontal connection tunnels). The head house building would be approximately 40m by 20m and approximately 13m high. This building would accommodate mechanical and electrical equipment rooms, emergency intervention and other infrastructure; • An auto-transformer station and an area of hardstanding would be located adjacent to the head house; • Unoccupied former industrial land adjacent to the existing Marylebone to Aylesbury Line tracks would accommodate a construction site compound to facilitate shaft construction; and • Protection of utilities crossing the tunnel corridor where required.

2.2.7 The tunnel portal at West Ruislip (see map CT‑06-017) would begin approximately 70m west of the Ickenham Road bridge and West Ruislip station and to the north of the Marylebone to Aylesbury Line. Key design features at this location would include: • A 120m covered section, a 90m propped section and a 260m open approach ramp; • On top of the covered section a 30m by 35m head house building, approximately 9m high, would be located to the south-east of the Ruislip Golf Course. This structure would accommodate mechanical and electrical equipment rooms, emergency intervention and other facilities; and • An area of hardstanding for maintenance and emergency vehicles at ground level adjacent to the head house building.

2.2.8 The tunnel portal would require the following additional key design features (see map CT‑06- 017): • Severance of the Ickenham Stream and diversion into a channel to the north of the route that would flow west to the River Pinn; • Diversion of an existing footpath adjacent to the Ickenham Stream to a new footbridge over the tunnel portal at a location approximately 135m to the east of the existing underpass8; and • Where required, protection or diversion of utilities in the vicinity of the Proposed Scheme. This would include a Thames Water sewer to the west of the existing footpath.

2.2.9 Continuing in a westerly direction, the route would diverge north-west, away from the Marylebone to Aylesbury Line on a section of retained embankment to Breakspear Road South (see map CT‑06-017 and CT‑06-018). Key design features of this section would include: • A new bridge over the River Pinn, approximately 25m north of the existing Marylebone to Aylesbury Line crossing; • Construction of a new bridge over Breakspear Road South, approximately 50m north of the existing Marylebone to Aylesbury Line crossing; • Works to Breakspear Road South and the existing utilities contained beneath it; and • Provision of new access arrangements to the research facility (Merck Sharp site) to the north of the route off Breakspear Road South.

2.2.10 After passing over Breakspear Road South the route would initially run west on embankment. It would then be at ground level for a short section before entering a cutting. The route would

8 Ickenham Stream is also referred to in this report as ‘the canal feeder’.

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be in cutting through the southern part of Newyears Green Covert to Harvil Road, the western boundary of the area (see map CT‑06-018). Key design features of this section would include: • A main construction site between Breakspear Road South and Harvil Road; • Realignment of Harvil Road to the east of the existing alignment including embankment, cutting and new bridges over the Proposed Scheme, the Marylebone to Aylesbury Line and Newyears Green Bourne stream; • A retained cutting north of the Marylebone to Aylesbury Line between Breakspear Road South and Harvil Road; and • Demolition of property in the south of the research facility (presently occupied by Merck Sharp). Land required for the Proposed Scheme

2.2.11 The Proposed Scheme would require land on both a temporary and permanent basis. The land required for construction is shown on the construction maps (map series CT‑05) and will be subject to review as the engineering design and formal ES is prepared. The final permanent and temporary land requirements will be set out in the formal ES. 2.3 Construction of the Proposed Scheme 2.3.1 This section sets out the key construction activities that are envisaged to build the Proposed Scheme in the South Ruislip to Ickenham area and the control measures that are proposed to manage the works. General descriptions of construction works that are relevant to the whole of the Proposed Scheme are provided in Volume 1. Environmental management and Code of Construction Practice

2.3.2 All contractors would be required to comply with the environmental management regime for the Proposed Scheme, which would include: • Code of Construction Practice (CoCP)9; and • Local environmental management plans (LEMP), which would apply within each CFA.

2.3.3 The CoCP, in conjunction with associated LEMPs, would be the means of controlling the construction works associated with the Proposed Scheme, with the objective of ensuring that the effects of the works upon people and the natural environment are eptk to a practicable minimum. The CoCP will contain generic control measures and standards to be implemented throughout the construction process.

2.3.4 A draft CoCP has been prepared and is published alongside this document. It will be kept under review as the design of the Proposed Scheme develops and further engagement with stakeholders is undertaken. Construction site operation Working hours

2.3.5 Core working hours would be from 08:00 to 18:00 on weekdays (excluding bank holidays) and from 08:00 to 13:00 on Saturdays. While there would not normally be any construction activity on Sundays, some activities (e.g. weekend possessions, tunnelling and vent shaft construction) would be undertaken. Site-specific variations to core hours and/or additional hours likely to be required would be included within LEMPs following consultation with the relevant local planning authority (LPA). To maximise productivity within the core hours, HS2

9 Arup/URS (2013), Phase One: Draft Code of Construction Practice. HS2 Ltd, London.

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Ltd’s contractors would require a period of up to one hour before and up to one hour after the core working hours for start-up and close down of activities. These activities would be subject to controls set out in the CoCP.

2.3.6 Track-laying activities and work requiring possession of major transport infrastructure (e.g. highways) may be undertaken during night-time, Saturday afternoon, Sunday and/or bank holidays for reasons of safety or operational necessity and would often involve work on consecutive nights, including over weekend possessions.

2.3.7 Bored tunnelling and directly associated activities (such as removal of excavated material, supply of materials and maintenance of tunnel boring machines (TBM) and other equipment) would be carried out on a 24-hour day, 7-day week basis. Where reasonably practicable, material would be stockpiled within the site boundary for removal during normal working hours. Construction site compounds

2.3.8 Main site compounds would be used for core project management (engineering, planning and construction delivery), commercial, and administrative staff.

2.3.9 Satellite site compounds would generally be smaller in size, providing office commodationac for limited numbers of staff. The satellite site compound would provide local storage for plant and materials and limited car parking would be provided for staff and site operatives. Limited welfare facilities would be provided at each site.

The location of all site compounds along with their duration of use and a broad current estimate of the number of workers likely to work at the construction sites is set out in Table 1 and shown in maps CT‑05-014 to CT‑05-018. Construction site details and arrangements are continuing to be refined and will be confirmed in the formal ES.

Compound Location Typical use Estimated Estimated number of type duration of workers use Average Peak working periods day10

Main Site Vent shaft at South Shaft construction 7 years To be 50 Ruislip confirmed (map CT‑05-015)

Main Site Tunnel portal at Portal construction 7 years To be 60 West Ruislip Tunnel drive launch site towards confirmed (map CT‑05-017) Greenpark Way

Main Site Between Tunnel construction and rail construction 7 years To be 260 Breakspear support, construction rail sidings, tunnel confirmed Road South and lining precasting Harvil Road in West Ruislip and connecting corridor to tunnel drive site at the portal at West Ruislip (maps CT‑05-017 and CT‑05-018)

10 Information relating to the estimated number of workers on an average working day will be confirmed in the formal ES.

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Compound Location Typical use Estimated Estimated number of type duration of workers use Average Peak working periods day10

Satellite Site Diversion of Bridge construction and stream diversion 1 year To be 20 Ickenham Stream confirmed to River Pinn and footbridge south of Ruislip Golf Course (maps CT‑05-017 and CT‑05-018)

Satellite Site Retained Piling, diaphragm wall and retaining wall 7 years To be 20 embankment construction confirmed south of Ruislip Golf Course and continuing directly west of Breakspear Road South (maps CT‑05-017 and CT‑05-018)

Satellite Site River Pinn Bridge construction. 1 year To be 20 underbridge confirmed (maps CT‑05-017 and CT‑05-018)

Satellite Site Breakspear Road Bridge construction 1 year To be 20 South underbridge confirmed (maps CT‑05-017 and CT‑05-018)

Satellite Site Private access west Road construction 0.5 years - - of Breakspear Road South (maps CT‑05-017 and CT‑05-018)

Satellite Site Cutting north Piling, diaphragm wall and retaining wall 1 year To be 50 of Marylebone construction confirmed to Aylesbury Line between Breakspear Road South and Harvil Road (maps CT‑05-017 and CT‑05-018)

Satellite Site Harvil Road Piling, earthworks, bridge construction 0.5 years To be 15 realignment confirmed (map CT‑05-018)

Satellite Site Harvil Road bridge Piling, earthworks, bridge construction 0.5 years To be 15 over Newyears confirmed Green Bourne (map CT‑05-018)

Satellite Site Harvil Road bridge Piling, earthworks, bridge construction 0.5 year To be 15 over Marylebone to confirmed Aylesbury Line (map CT‑05-018)

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Compound Location Typical use Estimated Estimated number of type duration of workers use Average Peak working periods day10

Satellite Site Harvil Road bridge Piling, earthworks, bridge construction 1.5 years To be 15 over Proposed confirmed Scheme (map CT‑05-018)

Table 1: Location of construction site compounds11

2.3.10 At the vent shaft and tunnel portal sites it is anticipated that the construction site compounds would be used to service preparatory and enabling works, earthworks, piling and in construction of the vent shaft and portal over the course of approximately 2.5 years. The remaining time would be required for fit out and commissioning. During this period the construction site compounds would remain in place. However, the total number of workers at each site would reduce and work at each site would be undertaken on an intermittent basis.

2.3.11 All main site compounds would contain space for the storage of bulk materials (aggregates, structural steel, steel reinforcement), an area for the fabrication of temporary works equipment and finished goods, fuel storage, plant and equipment storage and necessary operational parking. Buildings would be generally temporary modular units and layout would maximise construction space and limit land required. In urban areas it may be necessary to stack these units due to space restrictions. Hard standing areas would be installed at all site compounds.

2.3.12 The choice of construction site compound locations has been influenced by a number of factors, including the following: • Proximity to locations of major construction activities; • Proximity to major trunk roads; • Preference for disused industrial/commercial or previously developed land, where available; • Proximity of existing utilities or ease of establishing temporary services; • Ease of establishing and maintaining security; and • Considerations with respect to the amenity of communities including visual intrusion, light and noise pollution. Fencing and lighting

2.3.13 Security fencing would be provided on the perimeter of each site compound. Individual site compounds for offices, welfare and storage would generally be demarcated and secured with fences and gates. Fence type and construction would be appropriate to the level of security required, likelihood of intruders, level of danger, and visual impact to the environment.

2.3.14 Lighting of site compounds during hours of darkness would seek to minimise light pollution to the surrounding area, in accordance with the requirements of the CoCP.

11 The duration for each site compound is currently based on a draft programme, which will be refined for the formal ES.

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Temporary worker accommodation sites

2.3.15 There would be no accommodation sites in this area. Workers would be expected to travel to and from site on a daily basis using public transport or ride-share schemes. Construction traffic and access

2.3.16 The following lorry routes are currently proposed to access each of the site compounds: • The route to the compound between Harvil Road and Breakspear Road would be via Western Avenue (A40) continuing onto Breakspear Road South or Harvil Road. Vehicles unable to pass under the Breakspear Road South bridge would access the site via Swakeleys Road (B467) continuing onto Ickenham Road (B466), the A4180 and Breakspear Road South; • The route to the compound at the proposed tunnel portal at West Ruislip would be via Western Avenue (A40) continuing onto Swakeleys Road (B467) and Ickenham Road (B466); • The route to the compound for the vent shaft at South Ruislip would be via the A40 continuing onto Mandeville Road (A312), Eastcote Lane (turning in Field End Road) and Victoria Road; • The route to the compound at the River Pinn underbridge would be via Western Avenue (A40) continuing onto Breakspear Road South. Vehicles unable to pass under the Breakspear Road South bridge would access the site via Swakeleys Road (B467) continuing onto Ickenham Road (B466), the A4180 and Breakspear Road South; • The route to the compound for the Breakspear Road South underbridge would be via Western Avenue (A40) continuing onto Breakspear Road South. Vehicles unable to pass under the Breakspear Road South bridge would access the site via Swakeleys Road (B467) continuing onto Ickenham Road (B466), the A4180 and onto Breakspear Road South; • The route to the compound for the Harvil Road realignment and bridges would be via Western Avenue (A40) continuing onto Swakeleys Road (B467) and Harvil Road; • The route to the compound for the cutting between Breakspear Road South and Harvil Road would be via Western Avenue (A40) continuing onto Swakeleys Road (B467) and Harvil Road; and • The route to the compound for the embankment south of Ruislip Golf Course and directly west of Breakspear Road South would be via the A40 Western Avenue, Swakeleys Road (B467) and then directly from Ickenham Road or Breakspear Road South. Preparatory and enabling works Demolition works

2.3.17 It is anticipated that the Proposed Scheme would require the demolition of 10 structures in the area. These works are outlined in Table 2.

Description of structure Location

Commercial Ruislip Rifle Club

Commercial Ruislip Golf course driving range, Ickenham Road partial demolition

Commercial Ruislip Golf course outbuilding, north-east of club house

Residential Garage associated with 107 The Greenway

Residential The Lodge (owned by Merck Sharp and within the site boundary), west of Breakspear Road South

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Description of structure Location

Commercial Buildings to the west of Breakspear Road South (presently owned by Merck (multiple buildings) Sharp)

Infrastructure Harvil Road overbridge (bridge over Marylebone to Aylesbury Line)

Infrastructure Harvil Road Newyears Green Bourne underbridge

Residential Gatemead Farm

Residential Barn at Oak Farm

Table 2: Demolition works Drainage and culverts

2.3.18 It is anticipated that drainage ponds would be required for both railway track and highway drainage. Indicative locations are shown on maps CT‑06-014 to CT‑06-018. Watercourse diversions

2.3.19 The route of the Proposed Scheme and associated highway works require two diversions of watercourses as follows: • Ickenham Stream (canal feeder) located to the west of the portal at Ruislip (see maps CT‑05-017 and CT‑06-017) which would require a permanent diversion of approximately 600m; and • It may be necessary to temporarily divert the Newyears Green Bourne during construction of the new Harvil Road bridge (see map CT‑06-018). Utility diversions

2.3.20 There are a number of major items of utility infrastructure in proximity to the Proposed Scheme, including: high pressure gas mains; large diameter water mains; large diameter sewers; and high and low voltage electricity lines. In summary, the main utilities which are proposed to be protected or diverted in the area would be: • Protection of water and sewer utilities at Rabournmead Drive; • Protection of sewer between Victoria Road and Cedar Avenue; • Diversion of telecoms cables at South Ruislip Station cutting; • Protection of Thames Water sewers at Station Approach; • Protection of Affinity Water’s water main at Long Drive; • Protection of water main and sewer at Bridgewater Road; • Protection of Thames Water sewers at the Yeading Brook; • Diversion of Scottish and Southern Energy electricity cables (including a high voltage cable) and Protection of Affinity Water pipes and Thames Water sewers at West End Road; • Protection of National Grid gas main at West End Road overbridge; • Protection of British Telecom cable at Herlwyn Avenue; • Diversion and protection of Thames Water sewers and protection of Affinity Water pipes at West Ruislip Station; • Protection of Thames Water sewers and surface water drain parallel to London Underground Line;

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• Diversion of Scottish and Southern Energy electricity cables (including a high voltage cable), protection of British Telecom cables and protection of National Grid gas pipes at Ickenham Road overbridge; • Diversion of fibre optic cables alongside footpath at southern edge of uislipR golf course; • Diversion of Thames Water sewers to the east of Ickenham Stream; • Diversion of Thames Water sewer at the Greenway; • Diversion of Scottish and Southern Energy electricity cables (including a high voltage cable) to east of Breakspear Road South; • Diversion of Scottish and Southern Energy high voltage cable, British Telecom cable and National Grid gas pipe at Breakspear Road South underbridge; • Diversion of Affinity Water’s water mains and protection of Thames Water sewer at Breakspear Road South; • Diversion of Scottish and Southern Energy high voltage cable, National Grid gas main and Affinity Water’s water main to west of Breakspear Road South; • Diversion of Scottish and Southern Energy high voltage cables and line, Affinity Water’s water main and protection of Thames Water sewer at Harvil Road overbridge; • Diversion of National Grid gas main running north to south between Harvil Road and Breakspear Road South; • Diversion of Scottish and Southern Energy high voltage cable, National Grid gas main and Affinity Water’s water main to west of Breakspear Road South; and • Diversion of Scottish and Southern Energy high voltage cables and line, Affinity Water’s water main and protection of Thames Water sewer at Harvil Road overbridge.

2.3.21 Discussions with utility providers are underway to confirm whether plant and/or apparatus would need to be realigned away from the area of work; protected from the works; or have sufficient clearance from the work that they would not be affected.

2.3.22 Wherever practicable, temporary connections for construction site compounds would be made to local existing utility services (i.e. electricity, water, data, sewerage and surface water drainage, to reduce the need for generators, storage tanks and associated traffic movements for fuel tankers). Highway and road diversions

2.3.23 Proposed highway and road diversions are shown on map CT‑06-018 and include: • The permanent diversion of Harvil Road for 800m to the east of the existing road; and • The permanent diversion of the access road to the agricultural research facility (Merck Sharp site).

2.3.24 Generally, where roads would be affected by the Proposed Scheme, phased construction involving either permanent or temporary realignments or diversions, would be used to reduce disruption resulting from highway works.

2.3.25 Temporary highway diversions using the existing highway network would be implemented where these existing networks allow a relatively short diversion, with minimum disruption to travellers. Diversion duration would be reduced so far as practicably possible.

2.3.26 The preference is to maintain the existing alignment of a road which would require a bridge over or under the route. This approach requires suitable alternative routes to allow the road to

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be temporarily closed while the works are being undertaken. Where no suitable alternative routes are available a replacement road would be constructed near the existing road (an offline replacement) which would be open to traffic before the existing road is closed. Footpath, cycleway and bridleway diversions

2.3.27 Proposed footpath, cycleway and bridleway diversions are shown on map CT‑06-017 to CT‑06- 018 and shown in Table 3.

Name Location Permanent reinstatement or diversion

Route Approximate additional journey length12

PRoW adjacent to Ickenham Ickenham 135m east of existing route 270m Stream Stream, West Ruislip

Bridleway to east of Breakspear West Ruislip North of existing route Approximately Road South the same as existing

Table 3: Footpath, cycleway and bridleway diversions12 Restricted accesses

2.3.28 There would be no restricted accesses in the local area. Main construction works – Earthworks Earthworks

2.3.29 Major earthworks in the area would include: • Tunnel excavation; • Construction of the rectangular box shaft at South Ruislip; • Cutting south of Ruislip Golf Course (this is the ramp up from the portal and approximately 570m long); • Embankment from a point south of Ruislip Golf Course to Breakspear Road South (approximately 600m long); • Embankment from Breakspear Road South to a point 200m to the west; • Cutting between a point 200m west of Breakspear Road South to west of Harvil Road (approximately 1km in length and up to 20m deep); and • Embankment works from Newyears Green Bourne to south of proposed Harvil Road Marylebone to Aylesbury Line overbridge (approximately 300m long).

2.3.30 Works would be carried out in a sequence, taking due consideration of the impacts of road and footpath closures, flows within watercourses; and vehicle movements by road.

2.3.31 If a shortfall of fill material arises in this section of the ProposedScheme, where reasonably practicable, materials would be imported from surpluses generated on other sections of the Proposed Scheme. Where this is not possible due to the material being unsuitable, or the benefits of importing material are outweighed by the impacts of transportation, local sources of material would be identified.

12 Diversions of less than 50m are reported as negligible in this table.

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Main construction works – Structures Overview

2.3.32 The locations for the proposed structures are illustrated on maps CT‑06-014 to CT‑06-018. Underbridges

2.3.33 The Proposed Scheme would adopt underbridges and/or culverts to cross other linear infrastructure and watercourses. Generally (but not exclusively) of concrete construction, these structures under the railway would allow for the clearances required by other modes (e.g. typically 5.8m for highways) and/or flood clearance. In the case of watercourse crossings, the type of crossing at each location varies depending on the status and importance of the watercourse taking into account flood risk, the length of crossing, third party requirements and local environmental constraints.

2.3.34 A simplified construction sequence for a typical viaduct or underbridge is provided in Volume 1.

2.3.35 New underbridges would be required, as illustrated on maps CT‑06-017 and CT‑06-018 at: • Breakspear Road South (permanent); • River Pinn (permanent); • Breakspear Road South (temporary); and • Harvil Road Newyears Green Bourne stream (permanent).

2.3.36 Provision would be made for the passage of aquatic wildlife along all crossings of ordinary watercourses and main rivers. Overbridges

2.3.37 Bridges over the route of the Proposed Scheme would generally (but not exclusively) be of concrete construction. Structures over the railway would provide a minimum clearance of 7.15m.

2.3.38 Some existing bridges would be modified or replaced to accommodate the Proposed Scheme.

2.3.39 New overbridges, as illustrated on maps CT‑06-017 and CT‑06-018 would be required at: • The foot bridge over the tunnel portal at West Ruislip; • Harvil Road – Proposed Scheme highway crossing; and • Harvil Road – Marylebone to Aylesbury Line crossing. Bored tunnels

2.3.40 The tunnels would be excavated using a TBM and segmental concrete lining to support the tunnel.

2.3.41 Two TBMs would be launched from the construction site compound at West Ruislip (see map CT‑05-017) and run in an easterly direction towards the shaft site at Greenpark Way (located in CFA5).

2.3.42 The TBM works by excavating the ground in front of the cutter-head and pushing forward on hydraulic rams. A construction railway would be progressively installed as the TBM advances, allowing concrete segments to be transported to the tunnel face and excavated material to be taken away. The excavated ground is supported by concrete segments erected within the TBM shield, bolted together and then grouted into their final position as theTBM advances.

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2.3.43 Once each tunnel has been excavated, the TBMs would be removed from the site at Greenpark Way in Ealing and decommissioned. The tunnels would then be cleared before being installed with track, signal and electrical equipment, ready for the railway line to be commissioned, following testing. Vent shaft

2.3.44 The construction of the vent shaft at South Ruislip (see map CT‑06-015) would be undertaken using diaphragm walls. Where adits are required to provide connections to the running tunnels, sprayed concrete lining (SCL) techniques would be used.

2.3.45 Diaphragm wall shaft construction methods require that a concrete guide wall is constructed at ground level, around the perimeter of the shaft. This marks out its shape and would be used to guide the digging machine. The digging machine is likely to be a vehicle/crane which controls a ‘grab’ bucket. The grab is suspended from the vehicle/crane and digs a trench from the surface, down to the required depth of the walls. Each trench would be dug in a series of panels.

2.3.46 As the depth of the trench increases, a non-hazardous bentonite fluid is used to temporarily fill and support the trench and stop it collapsing in on itself. This fluid would be mixed on site and reused following treatment.

2.3.47 Once the trench is at its required depth, a steel reinforcement frame would be lowered into place in the trench and surrounded by concrete to complete the diaphragm wall. The bentonite fluid that is displaced by the concrete and steel being introduced would be collected via a pumping system and reused.

2.3.48 On completion, the diaphragm walls would form the sides of a box that sits below the ground surface. The soil between the walls would be excavated in a series of “lifts” to start creating the shaft space. As the excavation gets deeper permanent and temporary propping between the walls would be installed to ensure stability of the structure. A roof slab and base slab would be created to complete the shaft and any temporary propping removed.

2.3.49 The construction sequence can be divided into the following main activities: • Enabling works, including utility diversions, site clearance and demolition; • Site establishment; • Construction of the box shafts using diaphragm wall techniques; • Construction of the remaining shaft internal works and installation of heavy machinery; • Connection to the rail tunnels would be completed with short adits, constructed using SCL techniques; and • Following installation of the ventilation equipment and construction of the head house over the shaft, the site would be demobilised, landscaped and commissioned. Tunnel portal

2.3.50 A tunnel portal would be constructed at West Ruislip. This structure would comprise a head house, approach ramp (with covered, propped and open sections) and retaining walls. The general sequence of construction would be as follows: • Retaining walls would be constructed to support the sides of the approach ramp using two methods. At the eastern end, where the ramp would be at its deepest, the retaining walls of the ramp structure would be formed by installing diaphragm walls. At the western end of the structure, the retaining walls would be formed either by smaller diaphragm walls or by secant or contiguous bored piles;

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• The ramp would be created by bulk excavation of material between the retaining walls in two phases; • At the eastern end of the ramp, initial ramp excavation work would be followed by construction of a slab to create a cover over the ramp. The excavation of the ramp would then continue and on completion, the base slab would be installed; • To the west of the covered section of ramp, props would be installed between the retaining walls and the ramp excavated beneath the propped section; • At the western end of the ramp a base slab would be installed (this would ultimately form the base for the tracks); and • The base slabs over the east end of the portal would be reinforced, concreted and the portal head house structure constructed over this part of the covered ramp. Rail infrastructure fit out

2.3.51 The principal elements of rail infrastructure to be constructed are track, overhead line equipment, communications equipment and power supply. The installation of track in open areas would be of standard ballasted track configuration, comprising principally of ballast, rail and sleepers. Further details are set out in Volume 1. Power supply

2.3.52 HS2 trains would draw power from overhead line equipment, requiring feeder stations and connections to the 400kV National Grid network. There is one feeder station within the local area (located within CFA7). In addition to feeder stations, smaller auto-transformer stations would be required at more frequent intervals. The anticipated location of the proposed auto- transformer station at South Ruislip is shown on map CT‑06-015. Landscaping and permanent fencing

2.3.53 Landscaping (i.e. earthworks, seeding and planting) would be provided to address visual and noise impacts, as well as to provide screening for intrinsically important ecological habitats and heritage features. Where appropriate, the engineering embankments and/or cuttings would be reshaped to integrate the alignment sympathetically into the character of the surrounding landscape. The planting would reflect tree and shrub species native to the local landscape. Opportunities for ecological habitat creation would be considered.

2.3.54 Permanent fencing would be erected and will be shown on maps to accompany the formal ES. Construction programme

2.3.55 A construction programme that illustrates indicative periods for each core construction activity in this area is provided in Figure 3.

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Figure 3: Indicative construction programme for the area Commissioning

2.3.56 Commissioning is the process of testing the infrastructure to ensure that it operates as expected. This would take place in the year prior to opening. Further details are provided in Volume 1. 2.4 Operation of the Proposed Scheme 2.4.1 In this area, HS2 trains would run at speeds up to 320kph in open sections, but slower in the tunnel. During Phase One of HS2, up to 14 trains per hour (tph) would pass in each direction. This would increase to a potential maximum of 18tph in each direction should Phase Two also become fully operational.

2.4.2 The trains would be either 200m (one-unit train) or 400m (two-unit train) long. They would run between the hours of 05:00 and 24:00 (Monday to Saturday) and between 08:00 and 24:00 (Sunday). When required, maintenance would be conducted outside those operating hours.

2.4.3 The operation of the Proposed Scheme is described in more detail in Volume 1.

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2.5 Community forum engagement 2.5.1 HS2 Ltd’s approach to engagement on the Proposed Scheme is set out in Volume 1.

2.5.2 A series of community forum meetings and discussions with individual landowners, organisations and action groups were undertaken. Community forum meetings were held on: • 20 March 2012 at Ruislip Manor Sports and Social Club; • 14 June 2012 at The Barn Hotel, Ruislip; • 26 September 2012 at The Barn Hotel, Ruislip; • 27 November 2012 at The Barn Hotel, Ruislip; and • 25 February 2013 at The Barn Hotel, Ruislip. 2.5.3 In addition to HS2 Ltd representatives, attendees at these community forum meetings typically included local residents (and residents groups), public representatives, representatives of local authorities, action groups, affected landowners and other interested stakeholders.

2.5.4 The main themes to emerge from these meetings were: • The relocation of services including the need to coordinate the works with third party utilities to avoid longer than necessary localised disruption; • The Heathrow spur location being above ground and the construction timetable associated with this; • Methods of tunnel construction; • Environmental surveys; • The position of the tunnel portal at West Ruislip and the potential extension of the tunnel westward, under the River Pinn; • Noise and vibration during construction and operation, particularly for homes near cuttings and at the tunnel portal; and • The location of construction sites and a proposed sub-station. 2.6 Route section main alternatives 2.6.1 The main strategic alternatives to the Proposed Scheme are presented in Volume 1. The main local alternatives considered for the Proposed Scheme within the local area are set out within this section.

2.6.2 Since April 2012, as part of the design development process, a series of local alternatives have been reviewed within workshops attended by engineering, planning and environmental specialists. During these workshops, the likely significant environmental effects of each design option have been reviewed. The purpose of these reviews has been to ensure that the Proposed Scheme draws the right balance between engineering requirements, cost and potential environmental impacts. Tunnel vent shaft

2.6.3 At West Ruislip the Proposed Scheme would include a single vent shaft on a previously developed site within a partially derelict retail park. Directly to the east of this vent shaft location is the disused South Ruislip ‘Arla Dairy’ site and to the south is the London Underground Central Line. Access to the site would be via Victoria Road to the north. This vent shaft location is one of two locations proposed in the January 2012 announced scheme.

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2.6.4 The second vent shaft location proposed in the January 2012 announced scheme was a site located in Ruislip Manor on a triangle of woodland between Herlwyn Avenue and Lawn Close. The London Underground Central Line runs directly to the south. This location was discounted at an early stage of alternatives evaluation because construction access was not possible.

2.6.5 Three alternative sites to the two sites proposed in the January 2012 announced scheme were considered as follows: • A site located to the west of Beechwood Avenue and Herlwyn Avenue in West Ruislip. The site is currently amenity grassland and lies to the north of the LUL Central Line; • A site located within a large area of public open space directly north of Ruislip Gardens Station and the existing railway. Yeading Brook runs to the west of the site and existing access is from Bridgewater Road; and • A site located in South Ruislip on a public car park directly to the south of Sainsbury’s superstore and accessed from Long Drive.

2.6.6 The configuration options that were considered as alternatives to the configuration proposed in the January 2012 announced scheme were: • A single vent shaft at the site located directly north of Ruislip Gardens Station; • Two shafts, one each at the site located to the west of Beechwood Avenue and Herlwyn Avenue and the site located in South Ruislip south of Sainsbury’s superstore; • Two shafts one each at locations west of Beechwood Avenue and Herlwyn Avenue and the Arla Dairy site; and • Three shafts, one each at the site located to the west of Beechwood Avenue and Herlwyn Avenue, the site located directly north of Ruislip Gardens Station and the site located in South Ruislip south of Sainsbury’s superstore.

2.6.7 Specific issues relating to the location of individual options were also considered: • The site located to the west of Beechwood Avenue and Herlwyn Avenue is close to a primary school; • The site located directly north of Ruislip Gardens Station is close to residential property, on grassland and in an area with a potential for flooding; and • The site located in South Ruislip south of Sainsbury’s superstore would result in a permanent loss of car parking spaces.

2.6.8 The use of one vent shaft, if sited in the appropriate location, was found to meet the engineering design specification requirements. In addition, constructing one site as opposed to two would reduce the cost.

2.6.9 Environmentally, the development of one site reduces the potential for impacts. The site identified was considered suitable as it is located on previously developed land in an industrial setting which is suitable for regeneration. Tunnel portal at West Ruislip

2.6.10 The Proposed Scheme would site the tunnel entrance (tunnel eye) approximately 70m west of Ickenham Road. The tunnel eye was originally sited directly west of Ickenham Road in the January 2012 announced scheme. The revised location avoids replacement of Ickenham Road bridge and temporary closure of Ickenham Road during tunnel portal construction. Five alternatives were considered for the position of the tunnel eye as follows: • 650m to the west of the January 2012 announced scheme location;

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• 1.15km to the west of the January 2012 announced scheme location with portal ramp rising at a gradient of 1.75%; • 1.15km to the west of the January 2012 announce scheme location with portal ramp rising at a gradient of 3.11%; • 1.15km to the west of the January 2012 announced scheme location with portal ramp rising at a gradient of 3.35%; and • 1.15km to the west of the January 2012 announced scheme location with portal ramp rising at a gradient of 3.5%.

2.6.11 A tunnel eye 1.15km to the west of the January 2012 announced scheme location with portal ramp rising at a gradient of 3.5% was considered to be the preferred option on environmental grounds as it reduces the effects of operational activities on the residential properties onThe Greenway (south of the route). However, this option was not selected due to engineering and cost reasons (see below).

2.6.12 The five options with the tunnel eye further to the west were considered to have significant engineering and cost consequences for the alignment of the route both inside this area and extending into the Colne Valley area and were rejected. Ickenham Stream diversion

2.6.13 The Proposed Scheme would involve the diversion of Ickenham Stream westwards towards the River Pinn. Two alternatives were considered as follows: • Diversion and pumped aqueduct over Proposed Scheme; and • Diversion and pumped aqueduct over Proposed Scheme and Network Rail lines.

2.6.14 Both of these alternatives would require an additional structure as well as a diversion.

2.6.15 The preferred option would not require visible above ground structures and the diversion could be integrated into the landscape mitigation options. In addition this option would not require any construction to the south of the route. Ickenham Stream footpath

2.6.16 The Proposed Scheme would include a new footbridge over the Proposed Scheme level with the top of the portal structure which would link by footpath to the existing underpass beneath the Marylebone to Aylesbury Line. Five alternatives were considered as follows: • A subway under the Proposed Scheme; • A subway under the Proposed Scheme and Marylebone to Aylesbury Line; • Closure of the footpath and diversion around existing footpath routes; • Closure of the footpath and diversion to new a footpath route along the Marylebone to Aylesbury Line corridor to Ickenham Road; and • A footbridge over the Proposed Scheme and Marylebone to Aylesbury Line.

2.6.17 Construction of both subway options was not considered feasible.

2.6.18 A footbridge is the preferred option on environmental grounds as it would retain a footpath close to the existing footpath alignment. A footbridge over the Proposed Scheme was considered to be the preferred option when compared to a footbridge over both the Proposed Scheme and the Marylebone to Aylesbury Line. The rejected footbridge option has the potential to impact on habitat to the south of the Marylebone to Aylesbury Line and, being raised above ground level, would create a structure with a potential visual impact.

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River Pinn bridge

2.6.19 The Proposed Scheme would include a crossing over the River Pinn. This would comprise a single-span bridge, with a minimum span length (less than 8m) to accommodate the river and the adjacent footpath. This differs from the structure proposed in the January 2012 announced scheme which was a viaduct with abutments outside the area at risk of flooding.Three alternatives were considered as follows: • A single-span bridge with a span length to allow for an 8m buffer from banks of the River Pinn; • A three-span bridge, to allow for an 8m buffer from banks of the River Pinn; and • A two-span bridge with a minimum bridge length to accommodate river and footpath.

2.6.20 The alternative options would result in greater construction and maintenance costs when compared with the preferred option.

2.6.21 The viaduct structure with abutments located outside the area at risk of flooding was the preferred option on environmental grounds as it would reduce the footprint in the flood zone compared to other options. All options would require some compensatory flood storage.

2.6.22 The Proposed Scheme is a single span bridge, with a minimum span length (less than 8m) to accommodate the river and the adjacent footpath. This was selected as the other options were considered to have significant engineering and cost consequences. Breakspear Road South bridge

2.6.23 The Proposed Scheme would retain the road on the existing alignment and level and the route raised on an embankment to meet the headroom requirements, as proposed in the January 2012 announced scheme. Three alternatives were considered as follows: • The Proposed Scheme level would remain on the same horizontal alignment and the road level would be lowered below existing level in order to provide required headroom; • A new rail bridge over the road with the road permanently realigned to the east of the existing alignment; and • A new rail bridge over the road with the road permanently realigned to west of the existing alignment.

2.6.24 Specific engineering considerations included the headroom required under the bridge.

2.6.25 Specific environmental considerations included the potential disruption to traffic movements on Breakspear Road South and Marylebone to Aylesbury Line operations; the size of the construction area and land take requirements and the potential for the Proposed Scheme to be visible from Brackenberry Farm and residential properties.

2.6.26 The Proposed Scheme avoiding road realignment was selected as it would cause the least disruption to the road network. Harvil Road

2.6.27 The Proposed Scheme would realign Harvil Road to the east and would create three new road crossings over the Proposed Scheme, Marylebone to Aylesbury Line and Newyears Green Bourne Stream as follows: • The realignment of the road or replacement of the Harvil Road bridge (a three-span masonry arch structure) over the Marylebone to Aylesbury Line. The bridge was assessed in 2001 and found to have 40 tonne live load capacity. Although the January 2012 scheme had

32 CFA Report – South Ruislip to Ickenham/No 6 I South Ruislip to Ickenham

no such proposals, it is expected that there would be a requirement to use the bridge for loads heavier than 40 tonnes and the bridge would therefore require replacement; • The realignment of Harvil Road would necessitate construction of a new road bridge over the Newyears Green Bourne Stream; and • A new bridge carrying Harvil Road over the Proposed Scheme.

2.6.28 Eight alternatives were considered for the new crossing and road alignment as follows: • Permanent realignment of the road to the west of the existing road and the construction of a new bridge over the Proposed Scheme and Newyears Green Bourne Stream; • The road maintained on the present horizontal alignment and the construction of a new bridge over the Proposed Scheme only; • The permanent realignment of the road to west of the existing road and construction of new bridges over the Proposed Scheme, Marylebone to Aylesbury Line and Newyears Green Bourne Stream; • The permanent realignment of the road to east of existing road and construction of new bridges over the Proposed Scheme, Marylebone to Aylesbury Line and Newyears Green Bourne Stream; • The permanent realignment of the road to west of the existing road and construction of new bridges over the Proposed Scheme and Newyears Green Bourne Stream; • The permanent realignment of the road to east of the existing road and construction of a new bridge over the Proposed Scheme only; • The road maintained on the present horizontal alignment and construction of new bridges over the Proposed Scheme and Marylebone to Aylesbury Line; • The permanent realignment of the road to the west of the existing road and construction of new bridges over the Proposed Scheme and Newyears Green Bourne Stream; and • The road maintained on the existing alignment across the Marylebone to Aylesbury Line but with new Marylebone to Aylesbury Line bridge.

2.6.29 Options retaining the existing Marylebone to Aylesbury Line crossing and retaining Harvil Road on its current alignment were considered to be a major risk to the project due to the 40 tonne weight restriction on the existing bridge. Options requiring closure of Harvil Road would involve road diversions during a seven-year construction period. All three options requiring road realignment were considered feasible.

2.6.30 Options requiring realignment of Harvil Road were identified as having the potential for increased habitat loss, including edge habitat to the Marylebone to Aylesbury Line with direct

impacts on Newyears Green SBII and Brackenbury Rail Cutting SBIII. A road maintained on the present horizontal alignment with a new bridge over the Proposed Scheme only was the preferred option on environmental grounds due to the reduced potential for environmental impacts. Newyears Green Bourne Stream bridge at Harvil Road

2.6.31 The Proposed Scheme would comprise a single-span bridge with abutments 8m clear of the stream. This bridge was not proposed as part of January 2012 announced scheme. Three alternatives were considered during the bridge option evaluation process as follows: • Single-span culvert (the existing 3m-4m culvert); • Multi-span culvert; and

33 CFA Report – South Ruislip to Ickenham/No 6 I South Ruislip to Ickenham

• Multi-span bridge crossing the floodplain.

2.6.32 The single-span bridge with abutments 8m clear of the stream was the preferred engineering option as this reduces the risk of flooding to Harvil Road.

2.6.33 A multi-span culvert was the preferred option on environmental grounds as the flood risk would not be altered upstream or downstream of the culvert. 2.7 Proposals for further consideration 2.7.1 The following proposals are to be considered for inclusion within the Proposed Scheme pending further assessment prior to issue of the formal ES: • Diversion of a National Grid high voltage power line; and • Location of a ‘Yellow’ plant rail maintenance siding.

34 CFA Report – South Ruislip to Ickenham/No 6 I South Ruislip to Ickenham Part C: Environmental topic assessments

35 CFA Report – South Ruislip to Ickenham/No 6 I Agriculture, forestry and soils 3 Agriculture, forestry and soils 3.1 Introduction 3.1.1 This section of the report provides a summary of the impacts and the likely significant effects to agriculture, soils and forestry arising from the construction and operation of the Proposed Scheme. The section covers soils, agricultural land quality, farm enterprises, forestry and agri- environment schemes. 3.2 Policy framework 3.2.1 Policy 7.22 of the London Plan seeks to encourage and support farming and land-based sectors, particularly in the green belt.

3.2.2 Saved Policy OL12 of the Hillingdon Local Plan: Part 2 seeks to prevent the irreversible loss of the best and most versatile (BMV) agricultural land and sets criteria for the acceptability of development on agricultural land. 3.3 Assessment scope and key assumptions 3.3.1 The assessment scope and key assumptions for the farm impacts and agricultural land quality assessments are set out in Volume 1. 3.4 Environmental baseline 3.4.1 The Proposed Scheme would pass under agricultural land lying at approximately 40m Above Ordnance Datum (AOD) at the eastern end of the area. This section of the Proposed Scheme would be in tunnel below a predominantly urban area. At the western end of the route, where the route would be above ground, it would cross into farmland to the north and north-west of Ickenham.

3.4.2 The underlying geology is the London Clay Formation and the Lambeth Group, which give rise to stoneless and clayey soils of the Windsor association which are seasonally wet and poorly drained13.

3.4.3 Provisional ALC mapping shows the area to comprise undifferentiated Grade 3 agricultural land, which is of good to moderate quality14. Detailed surveys confirm that the majority of the agricultural land within the study area is of Subgrade 3b quality, which accords with the Department for Environment, Food and Rural Affairs (Defra) predictions that area has a less than 20% likelihood of being of BMV quality, as shown on map CT‑02-0515.

3.4.4 The land use in the area is predominantly urban. Agricultural land uses are limited to areas of mixed grassland and arable in the east, and grassland in the west.

3.4.5 The agricultural surveys to date have identified six holdings in the study area, as set out below in Table 4, though limited data are currently available for three of these farms. These include a mixed commercial farm in the eastern part of the study area and grassland farms in the western part of the study area, to the north and south of the existing railway. Two smallholdings near Breakspear Road South are used for the grazing of cattle or occasional crops of hay.

13 CranfieldUniversity (2001), The National Soil Map of England and Wales 1:250,000 scale, National Soil Resources Institute, Cranfield University, UK. 14 Natural England; Provisional Agricultural Land Classification mapping at 1:250,000 (version date 10/01/2002); http://www.gis.naturalengland. org.uk/pubs/gis/gis_register.asp; Accessed 18 February 2013. 15 Defra (2005), Likelihood of Best and Most Versatile Agricultural Land.

36 CFA Report – South Ruislip to Ickenham/No 6 I Agriculture, forestry and soils

Holding Primary farming activity

Priors Farm, Ruislip No data available

Oak Farm Small-scale beef rearing

Gatemead Farm Small-scale beef rearing

Brackenbury Farm Grazing, limited data available

Copthall Farm Grazing, limited data available

Harvil Farm Grazing, limited data available

Table 4: Holdings that would be affected by the Proposed Scheme

3.4.6 There is one large block of woodland near Harvil Road (Newyears Green Covert) that does not appear to be in active management, and a smaller copse (Copthall Covert) to the south of the railway line. No farm diversification has been identified. 3.5 Construction Assessment of impacts and mitigation

3.5.1 HS2 Ltd would require all of its contractors to comply with the CoCP, which would include the following measures: • Measures to maintain farm access and avoid traffic over land which is used temporarily during construction; • Ensuring that each affected farm holding would receive specific and relevant liaison regarding the construction activities that would affect the holding; • Ensuring that agricultural land and corresponding soil quality can be reinstated post construction where this is the agreed end use; • Ensuring that the impacts on infrastructure and livestock for individual farm holdings would be reduced; • Ensuring that there is appropriate access provided to areas of severed land during and post-construction; and • Ensuring the appropriate handling and conservation of soil stockpiles to allow them to be reused without any substantive reduction in long term productive capability.

3.5.2 Soil resources would be stripped at the outset of the construction phase and stored. Where land is required temporarily for construction of the Proposed Scheme, stored soils would be used to reinstate those sites to a pre-construction agricultural condition. Soils removed from the area of permanent works would be utilised, where reasonably practicable, in the construction of the Proposed Scheme.

3.5.3 Seasonally wet soils of the Windsor association would be affected and care would be needed in handling and storing these soils to ensure that the soil structure is not damaged, and that the utility of the land post-restoration is returned to that comparable with the existing utility.

3.5.4 The majority of the agricultural land affected by the Proposed Scheme would be required for a temporary period only. Measures set out in the draft CoCP would assist to reduce effects on agricultural resources.

3.5.5 The temporary loss of Subgrade 3b land, during construction, and the permanent loss of a considerably smaller area, would not be a significant effect.

37 CFA Report – South Ruislip to Ickenham/No 6 I Agriculture, forestry and soils

3.5.6 Based on the information available for the draft ES, six holdings (Priors Farm, Oak Farm, Gatemead Farm, Brackenbury Farm, Harvil Farm and Copthall Farm), would be significantly affected by land loss. However, the majority of the land take would be required only temporarily and following construction these areas would be reinstated as agricultural land.

3.5.7 Two farm holdings would be affected by demolition. At Gatemead Farm the residential dwelling would be demolished and, at Oak Farm an agricultural barn would be removed. In both cases the loss of this infrastructure would be a significant residual effect during construction.

3.5.8 Following the restoration of agricultural land the same agricultural activities undertaken at present should be possible and there would be no severance effects. Permanent significant effects are not considered likely.

3.5.9 The construction process could lead to transportation of weed seeds and plants along the route. Since the land affected for the surface section of the route is largely in agricultural use there is the potential for the spread of existing weeds; particularly invasive and damaging weeds as listed in the Weeds Act 195916. Defra has powers to require occupiers of land on which they are growing to take action to prevent their spreading. Application of control measures within the CoCP would regulate this potential effect. Likely residual significant effects

3.5.10 At the height of construction there would be a significant effect on six holdings due to the proportion of the farm that would be removed (described above). Two would also be significantly affected by property demolition (Oak Farm and Gatemead Farm).

3.5.11 Following the construction phase much of the land would be restored and returned to agricultural use, and there would be no significant permanent residual effects associated with the construction of the Proposed Scheme. 3.6 Operation Assessment of impacts and mitigation

3.6.1 All transport corridors have a propensity to support weed growth, which may prejudice agricultural interests where they can spread to adjoining land. Comparison with other railway and highway land indicates that the operational area of the Proposed Scheme has this inherent potential.

3.6.2 The potential for the establishment and spread of weeds from the operational area is capable of being effectively addressed through the adoption by the network operator of an appropriate land management regime, which identifies and remedies areas of weed growth that might threaten adjoining agricultural interests. Likely residual significant effects

3.6.3 There are not considered to be any significant residual effects associated with the operation of the Proposed Scheme.

16 Weeds Act 1959 (7 & 8 Eliz II c. 54). London, Her Majesty’s Stationery Office.

38 CFA Report – South Ruislip to Ickenham/No 6 I Air quality 4 Air quality 4.1 Introduction 4.1.1 This section of the report provides an assessment of the impacts and likely significant effects on air quality arising from the construction and operation of the Proposed Scheme, covering nitrogen dioxide (NO2), fine particulate matter (PM10, PM2.5) and dust17. Emissions of these pollutants are typically associated with construction activities, equipment and road traffic. 4.2 Policy framework 4.2.1 The London Plan integrates economic, environmental, transport and social frameworks18. Specifically for air quality, it seeks to achieve reductions in pollutant emissions and minimise public exposure to pollution. Policy 7.14 sets out a number of objectives, such as minimising increased exposure to existing poor air quality, the need to reduce emissions from demolition and construction activities using best practice and the provision of on-site mitigation measures during development.

4.2.2 The Mayor’s Air Quality Strategy and Supplementary Planning Guidance on Sustainable Design and Construction sets out actions for improving London’s air quality and includes measures aimed at reducing emissions from transport and new developments19,20. A key objective of the Strategy is to make better use of the planning process so that new developments do not contribute to air pollution. Policy 3 also gives support to the expansion of competitive rail-based alternatives to aviation, including the development of a national high-speed rail network.

4.2.3 The LBH Local Plan: Part 1 (2012) includes strategic objectives that seek to improve and protect air quality (SO10) and minimise carbon emissions from new development and transport (SO11). It also contains specific policies to target areas of poor air quality for emissions reduction (Policy EM1) and prevent development that would lead to deterioration in local air quality (Policy EM8). Policy OE1 of the LBH UDP (Saved Policies) 2007, (now the Hillingdon Local Plan: Part 2) also seeks to refuse development that would result in detrimental emissions of dust, smell or other pollutants to air, unless adequate mitigation is provided.

4.2.4 In addition, local and regional guidance relevant to this assessment includes: LBH Air Quality Action Plan (AQAP) 2004; and LBH Air Quality Supplementary Planning Guidance 200221,22. 4.3 Assessment scope and key assumptions 4.3.1 The assessment scope and key assumptions for the air quality assessment are set out in Volume 1. 4.4 Environmental baseline 4.4.1 The environmental baseline reported in this section represents the environmental conditions identified within the study area. The main source of existing air pollutants in the area is emissions from road traffic, as is the case for nearly all parts of London.Concentrations of road traffic related pollutants are highest in central London and diminish towards the outer

17 PM2.5 and PM10 describe two size fractions of airborne particles that can be inhaled and therefore are of relevance for human health. The designations refer to particles of size less than 2.5 and 10 microns in diameter. 18 Greater London Authority (2011), The London Plan: Spatial Development Strategy for Greater London. 19 Greater London Authority (2010), Clearing the Air: The Mayor’s Air Quality Strategy. 20 Greater London Authority (2006), Sustainable Design and Construction: The London Plan Supplementary Planning Guidance. 21 London Borough of Hillingdon (2004), Air Quality Action Plan. 22 London Borough of Hillingdon (2002), Air Quality Supplementary Planning Guidance.

39 CFA Report – South Ruislip to Ickenham/No 6 I Air quality

boroughs. At places very close to roads where traffic flows are high, the airborne concentrations of the main pollutants are elevated substantially when compared to the ‘urban background’, as exemplified by locations near the A4023.

4.4.2 Estimates for NO2, PM10 and PM2.5 concentrations have been obtained from London-wide modelled pollution maps for 2008 and 2011, published by the Greater London Authority (GLA) in 201024. These maps have been used to characterise the baseline air quality in London in preference to the background concentration maps produced nationally by the Defra that have been used in the assessment on other parts of the route outside London. This is because the GLA maps reflect concentrations at all locations, including at the roadside, whereas the Defra maps are for background concentrations and do not include the effects of individual roads. It is therefore considered that the GLA maps provide a better indication of baseline conditions at a local level.

4.4.3 LBH maintains several automatic monitoring stations, although most are located near Heathrow and the M4. Until 2011, one was operating in the study area at the roadside in South Ruislip. In addition, the local authority has diffusion tube sites measuring concentrations of NO2, including one at Queensmead School located on Queens Walk 400m to the north of the route and one on Sidmouth Drive in South Ruislip 230m to the north of the route.

4.4.4 The data collected by LBH along with the GLA mapping data show that some areas of the study area currently experience long term and short term average concentrations of NO2 that are above the limit value or the national objective value, especially in close proximity to major roads25.

4.4.5 An AQMA is currently declared by LBH in respect of NO2 concentrations for the southern part of the borough, south of the Marylebone to Aylesbury Line.

4.4.6 Air quality limit values and objective values for PM2.5 and PM10 are met in most parts of the borough, but monitoring and mapping data indicate that concentrations could be in excess of those permitted by standards at some major roadside locations such as the M25.

4.4.7 Receptors in the study area include many residential properties and some commercial premises within 350m of construction activity and within 200m of the roads affected by changing traffic flows. There are no ecological receptors of statutory status. 4.5 Construction Assessment of impacts and mitigation

4.5.1 Impacts from the construction of the Proposed Scheme could arise from dust generating activities and emissions from construction traffic. As such, the assessment of construction impacts has been undertaken for human receptors sensitive to dust and exposure to NO2 and PM10, as well as ecological receptors sensitive to dust and nitrogen deposition.

4.5.2 Air quality would be controlled and managed during construction through the route-wide implementation of the CoCP, where appropriate. Specific measures included in the draft CoCP include: • Contractors being required to control dust, air pollution, odour and exhaust emissions during construction works;

23 Urban background denotes the majority of locations where air quality is not influenced strongly by a local source, such as a major road. 24 For 2011, the 2010 study provides a forecast from modelled data. 25 ‘Long-term concentrations’ are usually described by the annual average concentration. ‘Short-term concentrations’ refers to those which are measured as daily or hourly averages and for which standards refer to peak concentrations, usually captured as a percentile concentration. The short-term standard for NO2 is expressed as the 99.79th percentile of hourly concentrations in a year.

40 CFA Report – South Ruislip to Ickenham/No 6 I Air quality

• Inspecting and monitoring undertaken after consultation with LBH to assess the effectiveness of the measures taken to prevent dust and air pollutant emissions; • Cleaning (including watering) of haul routes and designated vehicle waiting areas to suppress dust; • Keeping soil stockpiles away from sensitive receptors (including historical features), watercourses and surface drains where reasonably practicable, also taking into account the prevailing wind direction relative to sensitive receptors; • Using enclosures to contain dust emitted from construction activities; and • Undertaking soil spreading, seeding and planting of completed earthworks.

4.5.3 In the South Ruislip to Ickenham area, potential dust-generating activities would occur at the major construction sites for the tunnel portal at West Ruislip, the vent shafts at South Ruislip, the TBM drive site at West Ruislip and the Breakspear Road South/River Pinn bridge works and foundation works. In addition, works to create the embankment and cutting between Breakspear Road South and Harvil Road also have the potential to generate dust. Dust emissions are most likely to be associated with demolition, site preparation works, construction of the vent shaft, tunnel drive activities, earthworks to create cuttings/ embankments and the use of haul routes to and from the construction site compounds.

4.5.4 Given the mitigation outlined within the draft CoCP, the assessment of impacts arising from dust emissions has concluded that these would be negligible in magnitude and the effect would not be significant.

4.5.5 Construction activity could also affect local air quality through the additional traffic generated on local roads as a result of construction traffic routes and changes to traffic patterns arising from temporary road diversions.

4.5.6 Examination of the changes in air quality as a result of changes in traffic flows for017 2 along the affected roads will be assessed in the formal ES. Likely residual significant effects

4.5.7 The methods outlined within the draft CoCP to control and manage potential air quality effects are considered effective in this location. Hence, no residual effects are identified at this stage. 4.6 Operation Assessment of impacts and mitigation

4.6.1 Impacts from the operation of the Proposed Scheme relate mainly to changes in the nature of traffic. There are no direct atmospheric emissions from the operation of trains (and hence also from vent shafts) that would cause an impact on air quality; these have therefore not been assessed.

4.6.2 Traffic data in the South Ruislip to Ickenham area would be screened to identify roads that require further assessment and to confirm the likely effect of the change in emissions from vehicles using those roads in 2026 as part of the formal ES. Likely residual significant effects

4.6.3 No residual effects would be anticipated at this stage for air quality in this area during operation of the Proposed Scheme.

41 CFA Report – South Ruislip to Ickenham/No 6 I Community 5 Community 5.1 Introduction 5.1.1 This section of the report provides a summary of impacts and likely significant effects on local communities resulting from the construction and operation of the Proposed Scheme. 5.2 Policy framework 5.2.1 A key objective of the London Plan is that London should be a place where people and businesses want to locate, with facilities to meet their needs. The London Plan seeks to achieve this by: • Ensuring that development proposals should protect and enhance facilities and services that meet the needs of particular groups and communities (Policy 3.1); and • Providing people, in their neighbourhoods, with a good quality environment in an active and supportive local community with the best possible access to services, infrastructure and public transport (Policy 7.1).

5.2.2 The London Plan contains a range of policies which seek to avoid the loss of community facilities and affordable housing. These include Policies 3.6, 3.14, 3.16, 3.18 and 3.19. Additionally, Policy 7.18 seeks to protect local open space.

5.2.3 The Hillingdon Local Plan: Part 1 (2012) contains strategic objectives SO3 that seek to prevent the loss of open space and promote social inclusion. Policies EM4, CI1 and CI3 seek to prevent the loss of public local open space, urban green space, community services and facilities, and education facilities. The Saved UDP Policies (2007) in Hillingdon Local Plan: Part 2 set out further specific guidance in Policies H3, R5, R8, R11 and BE34 in relation to residential accommodation, sports and community facilities, religious buildings, art, culture and entertainment facilities, education and health facilities, and public access to the waterside.

5.2.4 There are no allocations for development sites of more than 0.5 hectares (ha) located within 2km of the route centre line. 5.3 Assessment scope and key assumptions 5.3.1 The assessment scope and key assumptions for the community assessment are set out in Volume 1. 5.4 Environmental baseline 5.4.1 The study area includes the area of land within the construction boundary (comprising temporary and permanent land take), as well as a suitable additional area as relevant to inform the respective environmental topics upon which the assessment is based.

5.4.2 The baseline study area and baseline data would be further refined in light of ongoing assessment work undertaken as part of the EIA process.

5.4.3 Approximately two-thirds of the route in this area is in tunnel. The above ground section runs in cutting or on embankments from the tunnel portal at West Ruislip to Harvil Road. Therefore the baseline has focused on the areas around the vent shafts, construction site compounds at Breakspear Road South and Harvil Road, the tunnel portal at West Ruislip and the embankment to the west of Breakspear Road South.

5.4.4 The baseline study area is densely populated and includes the residential areas of Ruislip and Ickenham.

42 CFA Report – South Ruislip to Ickenham/No 6 I Community

Civic Way

5.4.5 Bourne Primary School, which caters for children of all abilities aged 3-11 years, lies approximately 340m to the south of the centre line of the route. Queensmead Secondary School, an academy that caters for 11-18 years, lies approximately 280m to the north of the centre line of the route. Both these facilities lie outside of the temporary and permanent land take. No other community facilities fall within the permanent land take or temporary land take.

5.4.6 Queensmead Sports Centre, a well-resourced facility with twelve 5 a-side pitches, tennis courts, an athletics track and a gymnasium falls outside the temporary land take and permanent land take approximately 160m to the north of the centre line of the route. South Ruislip Library is also located outside the temporary land take and permanent land take approximately 140m to the north of the centre line of the route. Station Approach and Long Drive

5.4.7 There is a cluster of shops along Station Approach at South Ruislip to the west of the route, including a hairdresser and beauticians, plumbers, a vets, computer shop, convenience stores and takeaways. These facilities all lie outside of the temporary and permanent land take.

5.4.8 The South Ruislip Christian Fellowship Centre lies approximately 250m to the south of the centre line of the route on Deane Avenue.

5.4.9 To the east of the Proposed Scheme there is another cluster of shops along Long Drive, including an estate agents, furniture and kitchen shop, dry cleaners, convenience stores, a betting shop, a restaurant and take away. These facilities all lie outside of the temporary and permanent land take.

5.4.10 The Days Inn Hotel and Middlesex Arms public house lie adjacent to the north of the temporary land take on Long Drive. South Ruislip

5.4.11 There is a small selection of shops on Victoria Road and St Gregory the Great Catholic Church is located behind Victoria Road approximately 250m to the north of the centre line of the route. A large DIY and gardening store lies adjacent to the temporary land take. These facilities all lie outside of the temporary land take and permanent land take. West End Road

5.4.12 There is a cluster of shops along West End Road that are adjacent to the temporary land take. These include a post office, chemist, convenience stores, takeaways, dry cleaners, betting shop and estate agents. The Bell public house is also located here.

5.4.13 A football pitch and three tennis courts (part of RAF Northolt) fall outside the temporary land take and permanent land take on West End Road, opposite Ruislip Gardens London Underground station.

5.4.14 Ruislip High School, which incorporates the Ruislip Adult Learning Centre and an Italia Conti Associates theatre arts studio, is located on Sidmouth Drive outside of the temporary land take and permanent land take but within 250m of the route. The Eilmar Montessori School and Day Nursery, a private nursery for up to 64 children, is found further along Sidmouth Drive just outside of the study area.

43 CFA Report – South Ruislip to Ickenham/No 6 I Community

Blenheim Crescent

5.4.15 The Ruislip Rugby club which is located to the east of the satellite site compound at Blenheim Crescent lies outside of the permanent and temporary land take, although a large part of its grounds fall within the study area. Tunnel portal at West Ruislip

5.4.16 The Ruislip Golf Course is located to the north adjacent to the permanent land take. However, the main construction site compound would require temporary land take of part of the golf course, in an area to the south and west of the driving range and club house. King George V playing field (located to the south of the Marylebone to Aylesbury Line), Ickenham Cricket Club Ground (located approximately 125m to the south of the centre line of the route), part of Mad Field Covert (located approximately 195m to the south of the centre line of the route) and Ickenham Allotments (approximately 140m to the south of the centre line of the route) are also located outside the temporary land take and permanent land take.

5.4.17 Ruislip Rifle Club, is an active facility with approximately 40 members (Brunel University also uses the facility) and is located within the permanent land take and temporary land take.

5.4.18 There is one footpath that crosses the permanent land take area. West of the tunnel portal and construction site compounds between Breakspear Road South and Harvil Road

5.4.19 The King George V playing field, Ickenham Cricket Club Ground, part of Mad Field Covert and Ickenham Allotments are located outside the temporary and permanent land take.

5.4.20 There is one footpath that crosses the site and falls in the permanent land take. Uxbridge Golf Course is located outside of the permanent land take and temporary land take. There are no other community facilities in the area and the remaining land is primarily open space and scattered woodland, which lies outside of the permanent land take and temporary land take.

5.4.21 Copthall Covert lies to the south-west of the area partially within both the temporary and permanent land take. This open space however is surrounded by private land and is not readily accessible to the public. 5.5 Construction Assessment of impacts and mitigation

5.5.1 The draft CoCP includes a range of scheme wide provisions which would help mitigate community effects associated with construction, including: • Appointment of community relations personnel; • A community helpline to handle enquiries from the public; • Sympathetic layout of construction sites to reduce nuisance; • Maintenance of public roads, cycle ways and PRoW around construction sites where reasonably practicable to avoid their deterioration due to construction traffic; and • Specific measures in relation to air quality and noise would also serve to reduce impacts on amenity for the neighbouring communities.

44 CFA Report – South Ruislip to Ickenham/No 6 I Community

Residential property

5.5.2 The route of the Proposed Scheme would require the demolition of residential property as described in Table 2. Residential dwellings that would be demolished are Gatemead Farm and The Lodge within the agricultural research facility (Merck Sharp site) on Breakspear Road South. Other residential properties that would be demolished include the garage associated with 107 The Greenway and a barn at Oak Farm.

5.5.3 It is considered, in the context of the community assessment, that the permanent loss of these dwellings is a minor adverse effect and is, therefore, not considered significant. Community infrastructure

5.5.4 The construction of the tunnel portal at West Ruislip would be serviced by a construction site compound to the west of Ickenham Road. It would require the use of the land currently occupied by Ruislip Rifle Club. The entire site would be required for the duration of the works (four and a half years) and the Rifle Club would be permanently lost from this site. There are no local alternative facilities of a similar nature. The licence conditions of the Rifle Club require the club to be in continuous operation which means that an alternative site would need to be found prior to the commencement of construction works. The loss of the Rifle Club would be a major adverse effect and would be significant.

5.5.5 The construction of the tunnel portal at West Ruislip would also require the temporary use of part of West Ruislip Golf Course. The Proposed Scheme would require part of the land that currently forms the driving range and two of the eighteen holes and an outbuilding. This would affect the ability of the golf course to function as an eighteen-hole competition course. The club house would not be affected. The Golf Course is owned by the LBH and is accessible to local residents. The temporary loss of land from the golf club site would therefore be a moderate adverse effect and would be significant. Public rights of way and open space

5.5.6 There would be no land take impacts on recreational PRoW or publicly accessible open space. Amenity

5.5.7 In the formal ES, the incidence of significant effects will be assessed, including in-combination effects, on community amenity. Likely residual significant effects

5.5.8 The loss of the Ruislip Rifle Club, the disruption to the West Ruislip Golf Course and the isolation of Copthall Covert would be a significant adverse effect on the community.

5.5.9 The development of specific mitigation measures where required, which could include improvement or provision of community resources as appropriate, will be reported in the formal ES. Further mitigation

5.5.10 No further mitigation has been identified at this stage. 5.6 Operation Assessment of impacts and mitigation

5.6.1 Within this study area, effects on the community resulting from the operation of the Proposed Scheme could potentially arise from changes to amenity.

45 CFA Report – South Ruislip to Ickenham/No 6 I Community

5.6.2 The assessment will draw upon other technical disciplines (e.g. air quality, sound, noise and vibration, landscape and visual, electromagnetic interference, traffic and transport) findings to inform the amenity assessment. The presence of in-combination impacts from these other disciplines could result in significant amenity effects on a number of community facilities and resources in the area. This will be reported in the formal ES. Likely residual significant effects

5.6.3 Residual effects, if present, will be reported as part of the formal ES.

5.6.4 Multiple (in-combination) community effects will be considered, and where significant, reported in the formal ES.

46 CFA Report – South Ruislip to Ickenham/No 6 I Cultural heritage 6 Cultural heritage 6.1 Introduction 6.1.1 This section of the report presents a summary of the impacts and likely significant effects on heritage assets and the historic environment as a result of the construction and operation of the Proposed Scheme. Heritage assets comprise: • Archaeological and palaeo-environmental remains; • Historic landscapes; and • Historic buildings and the built environment. 6.2 Policy framework 6.2.1 Policy 7.8 of the London Plan seeks to conserve the significance of London’s heritage assets and their settings through good planning and design, noting that archaeological assets should, where possible, be made available to the public in their original location, in-situ. Policy 7.9 requires an assessment of the significance of heritage assets when a development is proposed, and schemes should be designed so that the heritage significance is recognised and is used as a catalyst for regeneration.

6.2.2 The Hillingdon Local Plan: Part 1 2012 contains strategic objective SO1 which seeks to conserve and enhance heritage assets within the borough. Detailed policies for cultural heritage are set out in the Saved Hillingdon UDP policies, now the Hillingdon Local Plan: Part 2 including: • Policy BE1 requires that development be allowed to disturb remains of importance within archaeological priority areas only in exceptional circumstances; • Policy BE2 requires that Scheduled Ancient Monuments and their setting be preserved; • Policy BE3 seeks that, whenever practicable, sites of archaeological interest are investigated and recorded either before or during development; and • Policy BE4 notes that new development or demolitions within a conservation area must preserve or enhance the character or appearance of that area. 6.3 Assessment scope and key assumptions 6.3.1 The assessment scope and key assumptions for the cultural heritage assessment is set out in Volume 1.

6.3.2 Detailed Historic Environment Record (HER) data was obtained for an area of 500m from the centre line in Greater London. 6.4 Environmental baseline 6.4.1 There is archaeological evidence for settlement focused in the Colne Valley and the River Pinn. The earliest evidence is associated to prehistoric flint scatters and Bronze Age barrows. This indicates human activity across the landscape although there is no evidence for significant land use or settlement until the Iron Age. During archaeological excavations in the Colne Valley, Iron Age to Romano-British settlement was identified to the north of the West Ruislip worksite.

6.4.2 The extensive land management of the medieval to post-medieval period is indicated by the presence of ridge and furrow field systems still extant today within the landscape.The entire landscape remained rural in character prior to the 20th century, with small settlements,

47 CFA Report – South Ruislip to Ickenham/No 6 I Cultural heritage

scattered farmsteads and moated manors (such as Brackenbury Farm) characterising the land use.

6.4.3 The current landscape of the area changes from suburban modern residential and commercial developments in the eastern area to open countryside of farmland and golf courses in the western area. The urbanisation in the 20th century was partially due to the construction of the Great Central Railways line through the area in 1903.

6.4.4 There are two airfields which were initially constructed during the FirstWorld War: RAF Northolt was constructed in 1915 and RAF West Ruislip, which was initially constructed between 1917 and 1920.

6.4.5 Within the area of study only the following designated and non-designated assets are recorded. Designated assets

6.4.6 Designated assets are represented in maps CT‑01-07, CT‑01-08 and CT‑01-09.

6.4.7 There are no designated assets located within the permanent and temporary land take boundaries.

6.4.8 The following designated features are located within the draft Zone of Theoretical Visibility (ZTV) (see Section 9.3 of this report): • Two scheduled monuments – Brackenbury Farm medieval moated site, located adjacent to the temporary land take and a further medieval moated site located approximately 300m south of the Proposed Scheme; • Seven Grade II listed buildings – A group of three formed of the early 17th century Highway Farmhouse, associated late 16th century barn and 18th century forecourt walls, the 16th century Brackenbury Farmhouse and Brackenbury House, the 18th century Woodbine Cottage, Tile Kiln Lane, the 19th century buildings numbered one to 11 (odd numbers only) of The Green, West Drayton and the 20th century RAF Northolt Officers Mess; and • Parts of three conservation areas – Ickenham Village, Ruislip Village and Manor Way. Non‐designated assets

6.4.9 Within the area of permanent land take and temporary land take the following assets have been identified: • Bronze Age cremation vessels; • The site of the medieval to post-medieval Bourne Bridge; and • The site of RAF Northolt, a First World War to modern military airfield.

6.4.10 HER data identified a further 25 assets within the study area. This includes archaeological evidence of an Iron Age to Romano-British settlement that may extend into the permanent land take or temporary land take. There was also evidence for archaeological remains from the prehistoric to post-medieval period and three 20th century assets relating to the RAF Northolt site. 6.5 Construction Assessment of impacts and mitigation 6.5.1 The construction works have the potential to affect heritage assets. Impacts would occur to assets within the construction boundary, as well as the settings of heritage assets within the ZTV.

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6.5.2 The draft CoCP sets out the provisions that would be adopted to control effects on cultural heritage assets. The provisions include: • Management measures to control damage to assets that are to be retained within the area of temporary land take and the preparation of project wide principles, standards and techniques for works affecting heritage assets; • A programme of archaeological investigation and recording to be undertaken prior to construction works affecting the assets; and • A programme of historic building investigation and recording to be undertaken prior to modification or demolition of the assets.

6.5.3 In addition, in order to avoid or reduce impacts on heritage assets, the concrete tunnel segment production plant and worksite adjacent to the tunnel portal has been designed to avoid physical impacts on the scheduled monument at Brackenbury Farm.

6.5.4 Assets that would or might experience a significant physical affect in this area are: • Archaeological remains of an Iron Age to Romano British settlement of moderate heritage value which would be removed; • Archaeological remains associated with the Bronze Age cremations of moderate heritage value which would be removed; • Archaeological remains associated with Bourne Bridge of low heritage value which would be removed; and • Medieval remains associated with the medieval moated site at Brackenbury Farm of moderate heritage value which would be removed.

6.5.5 The setting of the scheduled Brackenbury Farm, a medieval moated site and a heritage asset of high heritage value would be significantly affected by the ProposedScheme.

6.5.6 The construction of the Proposed Scheme would not have an impact on any other identified heritage asset within the permanent and temporary land take and would not have an impact on the setting of any other designated asset identified with theZTV . Likely residual significant effects 6.5.7 The impacts of the construction phase on the heritage assets through setting changes are temporary, and therefore not considered to result in residual significant effects.

6.5.8 Although a programme of archaeological and historic building investigation contributes to knowledge gain, such works would not fully mitigate the effect or reduce the impact on heritage assets. The following permanent significant effects would therefore remain: • The removal of archaeological remains associated with Iron Age to Romano British settlement; • The removal of archaeological remains associated with the Bronze Age cremations; • The removal of archaeological remains associated with medieval moated site; and • The removal of archaeological remains associated with Bourne Bridge. Further mitigation

6.5.9 No further mitigation measures have been identified at this time.

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6.6 Operation Assessment of impacts and mitigation

6.6.1 There would be no effects on buried archaeological remains arising from operation.

6.6.2 The introduction of the Proposed Scheme is largely along existing rail land which assists in reducing potential impacts on the setting of the heritage assets. However parts of the Proposed Scheme cross the countryside east of Breakspear Road South and this includes elevated sections on embankment.

6.6.3 The provision of earthworks and planting would provide an effective means of mitigation to reduce the operational effects of the Proposed Scheme on the moated site at Brackenbury Farm which is a scheduled monument. However, mitigation would not be fully effective until planting has matured. Likely residual significant effects

6.6.4 There are no significant residual effects associated with the operation of the Proposed Scheme.

50 CFA Report – South Ruislip to Ickenham/No 6 I Ecology 7 Ecology 7.1 Introduction 7.1.1 This section of the report provides a summary of the predicted impacts and significant effects upon species and habitats as a consequence of the construction and operation of the Proposed Scheme. This includes effects upon sites recognised or designated on the basis of their importance for nature conservation. 7.2 Policy framework 7.2.1 Policy 7.19 of the London Plan seeks to ensure a proactive approach to the protection, enhancement, and management of biodiversity. Policy 7.21 seeks to retain existing trees of value and states that where there is any loss from development, these should be replaced following the ‘right place, right tree’ principle.

7.2.2 Strategic Objective SO 8 of The Hillingdon Local Plan: Part 1 2012 is to protect and enhance biodiversity. Policy EM7 seeks to protect and enhance all designated sites of importance for nature conservation, populations of protected and priority species and their habitats.

7.2.3 Policies BE32 and BE34 of the Saved Hillingdon UDP Policies, now the Hillingdon Local Plan: Part 2, seek to secure and enhance the role of rivers and other waterways as wildlife corridors. Policy EC3 has regard to the potential effects of development close to areas of nature conservative importance.

7.2.4 In addition, regional guidance relevant to this assessment includes the Mayor’s Biodiversity Strategy 200226. 7.3 Assessment scope and key assumptions 7.3.1 The assessment scope and key assumptions for the ecological assessment are set out in Volume 1.

7.3.2 The current assessment draws on existing information gathered from national organisations and from regional and local sources including the Greenspace Information for Greater London (GiGL). Key organisations from whom data has been sought but which has not yet influenced the assessment include the following: • Black Redstarts; • Invertebrate (groups) recorders; and • London Bat Group.

7.3.3 Field surveys undertaken to date have been limited to locations where landowner permission has been obtained or areas accessible to the public. They include (but are not limited to): • Scoping surveys of railway land at West Ruislip, the fields south of Ruislip Golf Course, the River Pinn, Ruislip Golf Course, Brackenbury Farm and the agricultural research facility (Merck Sharp site); • Phase 1 habitat surveys of railway land, the brownfield land at the shaft site at South Ruislip; • Bats – an initial roost assessment survey of buildings and trees within and adjacent to the Proposed Scheme; and

26 Greater London Authority (2002), Connecting with London’s Nature – The Mayor’s Biodiversity Strategy.

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• Winter bird surveys at Ruislip Golf Course, meadows south of Ruislip Golf Course and fields and woodland between Breakspear Road South and Harvil Road.

7.3.4 Surveys will continue during 2013, including (but not limited to) for the following, subject to access: • Great crested newt, dormouse, bats, plants, badgers, birds, reptiles and invertebrates.

7.3.5 The majority of the route in this section of the Proposed Scheme is in tunnel. Where surface waters are present in areas where the route would be in tunnel and potential interactions with the Proposed Scheme are considered unlikely, these have not been considered within the assessment. The Yeading Brook has therefore been scoped out of the ecological assessment, but is discussed further in Section 13 Water resources and flood risk. 7.4 Environmental baseline 7.4.1 This section presents the environmental baseline that is relevant to the consideration of impacts and effects reported in Sections 7.5 and 7.6. Details of the environmental baseline for the full search areas investigated in support of the ecological assessment will be provided in the formal ES.

7.4.2 Land within or adjacent to the above-ground sections of the Proposed Scheme in this area comprises a suburban environment in the eastern tunnelled section with residential areas, recreation grounds, light industrial areas, retail parks, roads and a railway depot. The environment is increasingly rural westward from the tunnel portal and includes agricultural land, Ruislip Golf Course and small pockets of woodland.

7.4.3 Statutory and non-statutory designated sites are shown on maps CT‑01-07 to CT‑01-09 and CT‑02-05.

7.4.4 There are no statutory designated sites within 500m of the Proposed Scheme.

7.4.5 Local Wildlife Sites (LWS) which are located within the extent of, or adjacent to, the above- ground extent of the Proposed Scheme or are considered potentially subject to significant effects are relevant to the assessment. There are three such sites within this section of the route and each is considered to be of district/borough value: • Ruislip Golf Course and Old Priory Meadows Site of Borough Importance (SBI) Grade I (SBI). The site is located partly within the Proposed Scheme at the River Pinn in West Ruislip. The site is made up of two sections on opposing banks of the river. The area to the west of the river comprises the Old Priory meadow, a site rich in wildflowers. A pond beside the railway embankment once supported great crested newts. However, the current status of great crested newts at this location is uncertain;

• Newyears Green SBI.I is located partly within the Proposed Scheme and comprises Newyears Green covert. The canopy is dominated by pedunculate oak, ash and hornbeam. Also present is the locally scarce, buckthorn (Rhamnus catharticus). Another locally scarce species, musk thistle (Carduus nutans), is in the field between the ditch and Highway Farm buildings; and

• Brackenbury Railway Cutting SBI.II is located partly within the Proposed Scheme and comprises a broad, wooded railway cutting. The dense tree and scrub cover is dominated by pedunculate oak, elder and English elm. An oak-dominated copse situated by the roadside to the south-west is also included in the site.

7.4.6 LWS within areas of bored tunnel are not relevant to the assessment and have been excluded from the descriptions provided here.

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7.4.7 Other habitats located outside of the designated sites identified above and which are relevant to the assessment include the following: • Mosaic Habitats – including railway land at West Ruislip and the brownfield land at the shaft site at South Ruislip which could include the habitat of principal importance open mosaic27. Habitat on previously developed land comprises a small area within an urban landscape and is considered to be of local/parish value; and • Woodland – along the railway land, and within Ruislip Golf Course and fields to the south. These areas of woodland provide good habitat connectivity within this area along the railway land west to the agricultural fields and between Ruislip Golf Course and the fields to the south and north. The woodland provides suitable habitat for bats, breeding birds, reptiles and terrestrial invertebrates. The habitat is considered to be of district/borough value.

7.4.8 A summary of the likely value of species covered by the assessment (excluding any features of species interest for which the sites described above are designated) is provided in Table 5.

Resource/ Value Rationale Receptor

Bats Up to county/ Suitable roost habitat is present for bats including buildings, woodland and tree belts metropolitan along the railway land, within Ruislip Golf Course and the trees within fields to the west of Breakspear Road South and woodland at Copthall Covert and Newyears Green Covert. Records indicate Natterer’s bat, brown long-eared bat and soprano pipistrelle (a species of principal importance are present in the local area). Suitable foraging habitat is present comprising wooded areas and tree belts along the railway land, within West Ruislip Golf Course, fields south of the golf course, Copthall Covert, Newyears Green Covert and hedgerows within the fields to the west of Breakspear Road South.

Hazel Up to county/ Suitable wooded habitat is present for dormouse at Copthall Covert, Newyears Green dormouse metropolitan Covert and the hedgerows in adjoining fields. The woodland and hedgerows are not considered to provide high quality habitat for dormouse and are considered unlikely to be present.

Great crested Up to county/ Suitable habitat is present for great crested newt including the ponds and terrestrial newt metropolitan habitat within West Ruislip Golf Course and within Copthall Covert. Great crested newt could be present in significant populations withinW est Ruislip Golf Course and potentially lower numbers in Copthall Covert where fewer ponds have been recorded to date.

Otter Up to district/ Suitable habitat is present including the River Pinn corridor which represents a single borough watercourse through which otter may pass.

Water vole Up to district/ Suitable habitat is present for water vole including the River Pinn and associated borough wetland habitats.

Breeding birds Up to district/ A number of bird species of interest are likely to be present in Ruislip Golf Course, (excluding red borough around the River Pinn, and the fields to the south. Scoping surveys indicate farmland kite) species are likely to be present around the agriculture research facility (Merck Sharp site) and fields and Brackenbury Farm and fields.

Red kite Up district/ Red kite are present in low numbers across Ruislip Golf Course and agricultural fields borough west of Breakspear Road South toward the Colne Valley. Red kite populations in the Chilterns and neighbouring regions are increasing, though sightings are less common in Greater London.

27 The Natural Environment and Rural Communities (NERC) Act came into force on 1 October 2006. Section 41 of the Act requires the Secretary of State to publish a list of habitats and species which are of principal importance for the conservation of biodiversity in England. Habitats of Principal Importance are indicated with capital letters from this point.

53 CFA Report – South Ruislip to Ickenham/No 6 I Ecology

Resource/ Value Rationale Receptor

Terrestrial Up to district/ Small heath butterfly is recorded near the railway land south of the route in West Ruislip. invertebrates borough A number of other habitats suitable for terrestrial invertebrate groups are present within rail land, fields and wooded areas around Ruislip Golf Course and to the south, the River Pinn Corridor, farmland and hedgerows to the west and the woodland blocks. It is likely that common terrestrial invertebrate species will be present and rarer or notable species could be recorded.

Plants Up to district/ A number of other habitats suitable for notable plants are present within rail land, fields borough and wooded areas around Ruislip Golf Course and to the south, the River Pinn Corridor, farmland and hedgerows to the west and the woodland blocks. It is possible that rare or notable species will be present.

Reptiles Up to district/ Slow-worm and common lizard have been recorded along the boundaries of the London borough Underground Metropolitan and Piccadilly lines to the north and south of where the route crosses the line in West Ruislip. Suitable habitat is present for reptiles in the rail land, Ruislip Golf Course, fields to the south of the golf course and agricultural field margins and habitat around the farm buildings to the west. These habitats are of high quality and have good connectivity to the wider landscape.

Table 5: Preliminary evaluation of likely value of protected and/or notable species occurring within this study area 7.5 Construction Assessment of impacts and mitigation

7.5.1 The following section considers the impacts and effects on ecological receptors as a consequence of construction of the Proposed Scheme. All assessments made are provisional, based on the preliminary assessment of the baseline value as presented in Section 7.4 of this report.

7.5.2 The following measures have been included as part of the design of the Proposed Scheme and avoid or reduce impacts on features of ecological value: • Tunnelling the eastern part of the Proposed Scheme in this section of the route has reduced habitat losses; • The Ickenham Stream will be diverted as part of the construction works which would result in the loss of open watercourse and riparian habitats, though these comprise closely managed grassland. Habitat creation within the southern part of West Ruislip Golf Course associated with the diversion of Ickenham Stream (canal feeder) will create a sinuous watercourse including native planting with locally appropriate species including some tree planting. This will reduce the impact of the loss of the stream and include some native tree planting within the golf course and partially mitigate for the loss of breeding bird, reptile, and terrestrial invertebrates; and • Construction within the golf course would permanently affect approximately 2ha of grassland and scattered trees representing approximately 10% of Ruislip Golf Course & Old

Priory Meadows SBII. Habitat creation for flood attenuation mitigation will include wetland habitats, grassland and scrub. This will reduce the impact of the loss of Ruislip Golf Course

& Old Priory Meadows SBII to local/parish level. 7.5.3 The assessment assumes implementation of the measures set out within the draft CoCP, which includes translocation of protected species where appropriate. The following measures are particularly relevant in this area: • Reinstatement of areas of temporary habitat loss; • Where practicable the timing of works to avoid or minimise impacts on protected species;

54 CFA Report – South Ruislip to Ickenham/No 6 I Ecology

• The control of noise and vibration control at source and by screening equipment; and • Measures to prevent the spread of invasive and non-native species.

7.5.4 Tunnelled sections of the route would not impact ecological features. However, the potential impacts of construction activities at the vent shaft site in South Ruislip and between the tunnel portal at West Ruislip and Harvil Road have been considered (see Section 2.3 for a description of construction activities associated with this section of the Proposed Scheme).

7.5.5 The Proposed Scheme would involve the permanent loss of a number of trees, small areas of woodland and a small number of buildings. A small number of the trees and buildings include features potentially suitable to support roosting bats. Species affected are considered likely to be common and present only in low numbers. The Proposed Scheme would also involve the permanent loss of approximately 30ha of habitats including woodland, railway land, farmland fields and hedgerow suitable for foraging bats. Loss of rail land and wooded habitat may result in loss of habitat connectivity for foraging bats. It is estimated that these impacts would result in a permanent adverse effect on the conservation status of bat species concerned which would be significant at up to a county/metropolitan level.

7.5.6 Construction at West Ruislip would permanently affect approximately 3ha of the Brackenbury

Railway Cutting SBII representing a loss of 58% of the site. This would result in the permanent loss of woodland and scrub habitats within the northern and western parts of the site. It would result in a permanent adverse effect on site integrity which would be significant at the district/ borough level.

7.5.7 Construction at West Ruislip including the diversion of Harvil Road would permanently affect

approximately 3ha of the Newyears Green SBII representing a loss of 16% of the site. This would result in the permanent loss of woodland habitats within the southern parts of the site. It would result in a permanent adverse effect on site integrity which would be significant at the district/borough level.

7.5.8 The Proposed Scheme would result in the permanent loss of up to 30ha of grassland, woodland, farm buildings and agricultural fields suitable for breeding birds. It would result in adverse effects on the conservation status of breeding birds and invertebrates significant at up to a district/borough level.

7.5.9 There is the potential that 2013 surveys will identify the presence of great crested newt.

7.5.10 Approximately 2ha habitats within the railway land, and grassland, wooded areas and trees within the golf course therefore represent potential terrestrial habitats for great crested newt. If present, there is the potential for a permanent adverse effect on the conservation status of the local great crested newt population that would be significant at up to a district/borough level.

7.5.11 Construction at the vent shaft site at South Ruislip would lead to the permanent loss of the majority of habitats classified as ‘ruderal’ within the habitat of principal importance. It would cause an adverse effect on the conservation status of the habitat which is significant at a district/borough level.

7.5.12 Hazel dormouse is considered unlikely to be present and therefore no impacts on this species are anticipated.

7.5.13 Otter and water vole are unlikely to be significantly impacted by the construction of the rail embankment near the River Pinn.

7.5.14 All other receptors are unlikely to be impacted by construction activities at more than a local/ parish level.

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7.5.15 A summary of likely significant residual effects is provided in Table 6. Local/parish effects, which in combination may be significant, will be described in the formal ES. Likely residual significant effects

7.5.16 Taking into account mitigation included in the design of the Proposed Scheme, anticipated significant residual ecological effects during construction are detailed inT able 6.

Resource/Receptor Residual effect Level at which effect would be significant

Bats Potential permanent adverse effect on conservation status due Up to county/metropolitan to loss of small number of bat roosts and the permanent loss of approximately 30ha of woodland, railway land, farmland fields and hedgerow habitats suitable for foraging

Brackenbury Railway Cutting Permanent adverse effect on site integrity due to loss of 3ha of District/borough SBI.I woodland and scrub habitats

Newyears Green SBI.I Permanent adverse effect on site integrity due to loss of 3ha of District/borough woodland habitats

Breeding birds (excluding red Permanent adverse effect due to loss of suitable habitat District/borough kite)

Terrestrial Invertebrates Permanent adverse effect due to loss of suitable habitat District/borough

Open mosaic habitats in Permanent adverse effect on conservation status due to loss of District/borough brownfield land approximately 0.6ha of this habitat of principal importance.

Great crested newt Potential permanent adverse effect due to loss of approximately District/borough 2ha habitats within the railway land and grassland, wooded areas and trees within the golf course which are potentially suitable terrestrial habitats for great crested newt

Table 6: Significant residual construction effects on ecological receptors within the study area Further mitigation

7.5.17 Further measures currently being considered but not yet part of the design include: • Green/brown walls may be integrated as appropriate within the design of the vent shaft head house; • Opportunities for the maintenance of habitat connectivity to protect bat flight paths during construction near Brackenbury Railway Cutting and Copthall Covert north to Newyears Green Covert; • Provision of replacement bat roosts and/or inclusion of bat roost features within new constructions or on trees as appropriate based on results of 2013 surveys; • Provision of suitable replacement terrestrial habitat for great crested newt, as required based on 2013 survey results; • Opportunities for habitat creation along the existing railway to the west of the Brackenbury Railway cutting to mitigate the loss of the designated sites; and • Creation of grassland, woodland and scrub habitats along the new rail alignment to mitigate the loss of semi-natural habitats.

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7.6 Operation Assessment of impacts and mitigation

7.6.1 The following section considers the potential effects on ecological receptors during operation of the Proposed Scheme. Assessments made are provisional, based on the preliminary assessments of baseline value presented in Section 7.4 of this report.

7.6.2 No design features have been included as part of the design of the Proposed Scheme in this section of the route to avoid or reduce operational impacts on features of ecological value.

7.6.3 Operation of high speed trains on an embankment in between Newyears Green Covert and Brackenbury Railway Cutting, agricultural fields and Copthall Covert to the south could result in the loss of habitat connectivity for foraging bats and disrupt existing flight lines. In addition there is the potential for adverse effects on bats as a consequence of collision with trains, turbulence and vortices at some locations. Pending the completion of further survey there is considered to be the potential for a permanent adverse effect on conservation status of the local bat populations that would be significant at up to the county/metropolitan level.

7.6.4 A summary of likely significant residual effects is provided in Table 7. Local/parish effects, which in combination may be significant, will be described in the formal ES. Likely residual significant effects

7.6.5 Taking into account mitigation included as part of the Proposed Scheme design, the anticipated significant residual ecological effects during operation are detailed inT able 7.

Resource/Receptor Residual effect Level at which effect would be significant

Bats Potential permanent adverse effect on conservation status due Up to district/borough to mortality incidents from collision with trains and loss of flight paths.

Table 7: Significant residual operational effects on ecological receptors within this study area Further mitigation

7.6.6 Further measures currently being considered but which are not yet part of the design include the following habitat enhancements to improve existing connecting habitats potentially used as flight paths by bats: • Provision of measures to facilitate the passage of species across the route where significant foraging or commuting routes would be disturbed; • Habitat enhancement along existing railway land; • Extension of Newyears Green woodland complex through planting of further woodland; and • Planting of new or extension of existing hedgerows within adjoining rail owned land.

57 CFA Report – South Ruislip to Ickenham/No 6 I Land quality 8 Land quality 8.1 Introduction 8.1.1 This section provides a summary of the likely impacts and significant effects to land quality and geology, as a result of the construction and operation of the Proposed Scheme. Consideration is given to land that contains contamination and land that has special geological significance, either from a scientific, mining or mineral resources point of view, including: geological sites of special scientific interest (SSSI), local geological sites (LGS), areas of current underground or opencast mining, and areas of designated mineral resources.

8.1.2 Areas of land have been identified, both within and adjacent to construction areas, that could affect or be affected by the construction of the route because they are contaminated (for example, contaminated soils may need to be removed or the construction may alter existing contamination pathways). Each of these areas has been studied in order to determine the scale of any potential impacts caused by existing contamination and what needs to be done to avoid significant consequences to people and the wider environment. In addition, a review has been undertaken to establish whether the operation of the Proposed Scheme would lead to contamination of its surroundings and what needs to be done to prevent such contamination. This process is known as a ‘contamination risk assessment’. 8.2 Policy framework 8.2.1 Policy 7.20 of the London Plan seeks to ensure that development proposals should, wherever possible, make a positive contribution to the protection and enhancement of geodiversity. Policy 5.21 supports the remediation of contaminated sites.

8.2.2 Hillingdon Local Plan: Part 1 2012 strategic objective SO5 seeks to safeguard areas of geological importance. A number of detailed policies are also contained within the Local Plan: Part 1 2012, including: Policy EM7 (seeks to preserve and enhance the borough’s geological conservation); Policy EM 8 (seeks to safeguard groundwater quality and ensure development on contaminated land includes appropriate mitigation); and Policy EM9 (affords protection to safeguarded mineral resources). The Hillingdon Local Plan: Part 2 Saved UDP Policies OL21 and OL22 also seek to restore damaged, derelict and degraded land and ensure reasonably practicable measures are implemented to negate or contain the causes of the land’s unsatisfactory condition. 8.3 Assessment scope and key assumptions 8.3.1 The assessment scope and key assumptions for the land quality assessment are set out in Volume 1. 8.4 Environmental baseline Geology

8.4.1 A cover of made ground may be present due to the presence of an existing rail corridor (comprising track-bed materials and existing embankments) as well as previous cycles of development along the edge of the railway28.

28 ‘Made ground’ is a term given to any man-made or artificial deposits. It may be derived from a variety of materials including entirely natural products such as quarried stone, sand, gravel or clay or from the residues of industrial processes (such as ash or clinker) or a mixture of materials. It is frequently used interchangeably with the term ‘fill’.

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8.4.2 Superficial deposits are present at the western end of this section of the ProposedScheme and comprise a narrow ribbon of alluvium associated with the River Pinn29,30.

8.4.3 The bedrock geology comprises an outcrop of the Lambeth Group present to the north of the route at Ruislip Gardens Station and also approximately 200m either side of the River Pinn. In this area it is described as mottled sandy clay and clayey sand. The bedrock geology underlying the remainder of the study area is the London Clay Formation. The Lambeth Group is directly underlain by the Cretaceous Chalk Group in this area. Groundwater and surface water

8.4.4 The alluvium and Lambeth Group are both designated by the Environment Agency (EA) as Secondary A Aquifers, whilst the Chalk is classified as a Principal Aquifer (map CT‑04-05).

8.4.5 The London Clay Formation is classified by the EA as an unproductive strata (i.e. is not considered to represent a usable groundwater resource).

8.4.6 The route also crosses a number of surface water bodies including: the eastern and western arms of the Yeading Brook; Ickenham Stream (canal feeder); and the River Pinn (map CT‑04-05).

8.4.7 Information provided by the EA for the study area indicates that there are: • Two licensed groundwater abstractions for public water supply which have associated SPZs within 1km of the route. The route would pass through one SPZ1 which is located 300m to the west of West Ruislip Station at the western edge of the study area (map CT‑04-05). The abstractions are all from the Chalk aquifer; • Three other licensed groundwater abstractions within 2km of the route. These abstract water from the Chalk aquifer; and • Two additional water wells within 500m of the route for unknown use. These are expected to abstract water from the Chalk aquifer. Further information will be included in the formal ES if available.

8.4.8 Groundwater and surface water resources are discussed in more detail in Section 13 Water resources and flood risk. Current and historical land use

8.4.9 Historically, there have been relatively few potentially contaminating activities in the area. With the exception of the rail corridor and associated sidings, these were limited to small industrial sites located around South Ruislip Station and a large depot area either side of the route at West Ruislip.

8.4.10 Current potentially contaminating land uses (in addition to the railway) include a business park, small industrial estate and depot area; a waste transfer station which neighbours South Ruislip Station and an agricultural research facility (Merck Sharp site) on Breakspear Road South. An oil depot is also located adjacent to the study area on Harvil Road approximately 170m to the south of the route.

29 ‘Superficial deposit’ is a term given to a geological deposit or formation that was laid down during the Quaternary period (within the previous 2.6 million years). Such deposits were largely formed by fluvial (river) and glacial or periglacial processes including wind-blown deposits known as ‘loess’. 30 ‘Alluvium’ is a term given to any deposits laid down by rivers. It may variably comprise clay, silt, sand and gravel depending upon the source materials and depositional environment. Alluvium can also contain lenses of organic matter (peat) and may be highly variable in vertical and lateral composition.

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8.4.11 The higher-risk sites, both historical and current land uses, identified by the assessment comprise the following (listed from east to west)31:

• Various former works and depots that now form part of Victoria Road trading estates (at the location of the vent shaft at South Ruislip) (map CT‑03-08); • Rail land in the far western part of the study area (map CT‑03-09); • The agricultural research facility along Breakspear Road (map CT‑03-09); and • Oil depot on Harvil Road (although actually situated in the adjacent Colne Valley CFA this has been considered) (map CT‑03-09).

8.4.12 The principal source of potential contamination is likely to be the longstanding rail corridor. This could include various metals, semi-metals, inorganic and organic compounds and asbestos.

8.4.13 Potential sources of contamination in the area are largely underlain by the low permeability London Clay. The London Clay is known to provide an effective barrier to contaminant migration and any contamination present is likely to be localised. In the Ickenham area, where reference information indicates it is underlain by the Lambeth Group (which is classified as Secondary A Aquifer), land use is primarily agricultural (with the exception of the rail corridor). Mining/mineral resources

8.4.14 There is no record of mining or mineral resources within the study area. Geo-conservation resources

8.4.15 Supplementary planning guidance issued by the London Geodiversity Partnership indicates that there are no current or potential geological designations in the study area32,33. Receptors

8.4.16 The following potential receptors within the South Ruislip to Ickenham area have been identified: • Residents and workers who would be present adjacent to the proposed works; near the tunnel portal at West Ruislip and shaft at South Ruislip, • Site workers within the existing rail land and commercial properties around the shaft site at South Ruislip; • The Secondary A Aquifers; • Yeading Brook; Ickenham Stream (canal feeder); and the River Pinn; and • The built environment (such as listed buildings/structures, housing or foundations to structures). 8.5 Construction Land contamination Assessment of impacts and mitigation

8.5.1 The draft CoCP requires that a programme of ground investigation would take place prior to construction in order to confirm areas of contamination. A risk assessment would be

31 The definition of ‘higher-risk’ sites in this instance relates to the contamination potential of the source, the type of construction works that are proposed at that location (e.g. tunnel, cutting or embankment) and the proximity of receptors e.g. people, groundwater bodies etc. 32 Green infrastructure and open environments: London’s Foundations: Protecting the Geodiversity of the Capital Supplementary planning guidance, BGS/Natural England, March 2012. 33 Regionally or Locally Important Geological or Geomorphological Sites (RIGS/LIGS) or Geological Sites of Special Scientific Interest.

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undertaken to determine what, if any, site-specific remediation measures would be required to allow the Proposed Scheme to be constructed safely and to prevent harmful future migration of contaminants.

8.5.2 Approximately 70% of the route through the area would be in tunnel below ground surface. The areas of above ground works within the South Ruislip to Ickenham area are limited to the shaft site at South Ruislip within the existing industrial estate, the tunnel portal and deep cutting located to the west of West Ruislip Station, and the cutting/embankment works between Breakspear Road South and Harvil Road.

8.5.3 The proposed tunnel portal and much of the cutting are located in open fields, with the exception of where it cuts through the existing railway and agricultural research facility located to the west of Breakspear Road South.

8.5.4 A relatively large construction site compound is proposed on open fields to the south of the existing railway to the east of Harvil Road. The compound would not coincide with any previously developed land, although part of the area was used as a construction site compound for the installation of a high pressure gas main.

8.5.5 For the receptors (humans, built environment) considered along the tunnelled section of the Proposed Scheme, the construction phase is expected to have no significant effect as the London Clay and cohesive Lambeth Group provide an effective barrier around the works.

8.5.6 For the remainder of the route through this area, the principal effects on receptors from potential sources of contamination relate to the potential for soil disturbance and off-site migration of contaminants. In particular, the shaft at South Ruislip would be constructed on land adjacent to Victoria Road (located on industrial land at the former Arla Dairy site) which has some history of potentially contaminating uses and is located adjacent to existing rail line.

8.5.7 In addition, the above ground section to the west of West Ruislip Station cuts through an agricultural research facility and is adjacent to land with a history of railway use, although it is noted that the latter comprises lower risk running lines rather than higher risk servicing or depot areas. Construction activities in these areas may result in disturbance of contamination, albeit in the case of this type of rail land, this is judged likely to be relatively minor.

8.5.8 During the construction phase, the principal effects on receptors from the potential sources of contamination identified relate to the potential for soil disturbance and subsequent off-site migration of contaminants (e.g. through wind-blown dust or vapours) or during escape of contaminating substances that are used in construction (e.g. fuels).

8.5.9 However, when the measures outlined in the draft CoCP are implemented, it is anticipated that contamination risks to off-site land users would remain negligible and therefore there would be no significant effects.

8.5.10 At the western end of this section of the Proposed Scheme, adjacent to the River Pinn, the route would be constructed over Secondary A Aquifers (alluvium and Lambeth Group). Construction activities would be located in open fields and it is considered unlikely that there would be any pre-existing contamination. As such, provided that measures detailed in the draft CoCP are implemented, no effects on the aquifers (or adjacent watercourse) are anticipated to be associated with land contamination (where present).

8.5.11 Contaminated soils excavated from the site, wherever feasible, would be treated as necessary to remove or render any contamination inactive, and reused within the Proposed Scheme where needed and suitable for use. Techniques are likely to include stabilisation methods, soil washing and bio-remediation to remove oil contaminants. Contaminated soil disposed off-site

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would be taken to a soil treatment facility, another construction site (for treatment, as necessary, and reuse) or an appropriately permitted landfill site.

8.5.12 It is considered unlikely that additional remediation works would be required over and above the standard mitigation measures outlined within the draft CoCP.

8.5.13 Whilst the construction compounds would store and use potentially contaminative materials such as fuels, oils and solvents, they would be managed in accordance with the CoCP, thus minimising the impacts of contamination from these sources. Likely residual significant effects

8.5.14 Where remediation of contaminated soils or groundwater has been carried out, there would be a minor beneficial effect for the environment in the long term with respect to contamination. This effect would not be significant in the context of this assessment. Mining/mineral resources Assessment of impacts and mitigation

8.5.15 There are no mining or mineral resources within the area and as such there are no impacts upon these resources/receptors. Likely residual significant effects

8.5.16 No residual effects have been identified at this time. Geo-conservation resources Assessment of impacts and mitigation

8.5.17 There are no geo-conservation resources within the area, as such there are no impacts upon these resources/receptors. Likely residual significant effects

8.5.18 No residual effects have been identified at this time. 8.6 Operation Assessment of impacts and mitigation

8.6.1 Maintenance and operation of the railway would be in accordance with environmental legislation and best practice. Spillage and pollution response procedures similar to those outlined in the CoCP would be established for all high risk activities and employees would be trained in responding to such incidents.

8.6.2 An auto-transformer station is proposed to be located at the location of the vent shaft at South Ruislip. An auto-transformer station can, in principle, be a source of contamination through accidental discharge or leaks. However the proposed auto-transformer station, in common with other modern substations, would use secondary containment thereby minimising the likelihood of future contamination.

8.6.3 There exists the potential of minor leakage of hydraulic or lubricating oils from the trains. However, such leakage or spillage is expected to be very small and would not lead to any significant contamination.

8.6.4 Where contamination remediation works have been carried out during the construction period, there may need to be a requirement to undertake post-remediation monitoring of, for example, groundwater.

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Likely residual significant effects

8.6.5 Residual pollution associated with the operation of the Proposed Scheme is not considered to be significant.

63 CFA Report – South Ruislip to Ickenham/No 6 I Landscape and visual assessment 9 Landscape and visual assessment 9.1 Introduction 9.1.1 This section of the report presents the assessment of the likely significant landscape and visual effects. It starts by describing the current conditions found within and around the route of the Proposed Scheme, the nature and pattern of buildings, streets, open space and vegetation and their interrelationships within the urban environment. A summary of the significant effects that would arise from the construction and operation on landscape character areas and visual receptors is provided. 9.2 Policy framework 9.2.1 The London Plan Policy 7.2 states that all new development should achieve the highest standards of accessible and inclusive design. Policy 7.4 states that development should respect local character and provide a high quality design response (and sets out various factors that contribute to this). Policy 7.6 highlights a variety of aspects that should be taken into account in the design of new buildings and structures.

9.2.2 Policy EM2 of the Hillingdon Local Plan: Part 1 2012 seeks to maintain the strategic functions of the green belt, whilst Policy BE1 of the Hillingdon Local Plan: Part 1 seeks to ensure that development is appropriate to the context of townscapes, landscapes and views. Additionally, Saved UDP Policy OL9 in the Hillingdon Local Plan: Part2 seeks to maintain the condition and use of open land within the Western Avenue (A40 Area of Environmental Opportunity); Saved UDP Policy BE38 seeks to retain topographical and landscape features; and Saved Policy OL26 seeks to protect trees and woodlands within the landscape.

9.2.3 In addition, local and regional guidance is relevant to this assessment including: • London View Management Framework 201234; • Green Infrastructure and Open Environments: All London Green Grid, 201235; • National Character Areas 200536; • The London Regional Landscape Framework 201137; • Tranquillity mapping 200038;and • Ickenham Village Conservation Area Map, 200839. 9.2.4 The emerging policy baseline will be available as part of the formal ES. 9.3 Assessment scope and key assumptions 9.3.1 The assessment scope and key assumptions for the landscape and visual assessment are set out in Volume 1.

9.3.2 LBH has been consulted on the extent of the landscape and visual study area, the distribution of visual receptor viewpoints and the location of verifiable photomontages. Field surveys were

34 Mayor of London (2012), London View Management framework, Greater London Authority, http://www.london.gov.uk/priorities/planning/ vision/supplementary-planning-guidance/view-management. Accessed 24 May 2012. 35 Mayor of London (2012), Green infrastructure and open environments: The all London green grid, Greater London Authority, http://www.london. gov.uk/priorities/planning/vision/supplementary-planning-guidance/view-management. Accessed 24 May 2012. 36 Countryside Commission (1998), Countryside character, South East and London national character areas, Countryside Agency, http://www.naturalengland.org.uk/publications/nca/southeast.aspx. Accessed 24 May 2012. 37 Natural England (2011), London’s Natural Signature, The London Landscape Framework. Alan Baxter, Sheils Flynn http://www.naturalengland. org.uk/regions/london/ourwork/wildlondon/naturalsignatures/default.aspx. Accessed 24 May 2012. 38 CPRE Tranquillity Map: England; www.cpre.org.uk/resources/countryside/tranquil-places/item/1839. Accessed 16 April 2013. 39 London Borough of Hillingdon Council, Ickenham Village Conservation Area Map 2008, http://www.hillingdon.gov.uk/media/pdf/p/7/Ickenham_ Village_CA.pdf. Accessed 24 May 2012.

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undertaken from January to March 2013, including photographic studies of LCAs and visual assessment of viewpoints. Further surveys will be undertaken during 2013 and reported in the formal ES.

9.3.3 The study area has been informed by early drafts of the zone of theoretical visibility (ZTV), which is being prepared for inclusion in the formal ES. LCAs and visual receptors within approximately 500m of the Proposed Scheme have been assessed. Long distance views of up to 1km have been considered at locations such as Glovers Grove and Breakspear Road South. The study area extends beyond all land required for the Proposed Scheme. 9.4 Environmental baseline 9.4.1 The following section sets out the baseline conditions for the landscape and visual assessment in the study area. Maps LV-11-07 and LV-11-08 show the location of landscape character areas and visual receptor viewpoints.

9.4.2 The study area is predominantly suburban in character in the east and becomes more rural in character north and north-west of Ickenham with widespread residential development and some industrial sites at South Ruislip. However, there are also extensive green spaces within the study area, largely south of the existing Marylebone to Aylesbury Line railway corridor, including the area associated with the RAF Northolt aerodrome and West Ruislip/Ickenham area. Ruislip Golf Course forms a green wedge at the west end of the study area and forms a link to the open spaces west of Ruislip and Ickenham. The Marylebone to Aylesbury Line railway corridor is well vegetated at the eastern end of the study area, along the southern boundary of Ruislip Golf Course and within the Newyears Green Covert, adjacent to Harvil Road.

9.4.3 Western Avenue (A40) is the primary road in this area and runs in an east-west orientation. The Marylebone to Aylesbury Line and an over-ground section of the London Underground Central Line also run from east to west; West End Road (A4180) runs north-south through the area.

9.4.4 Public Rights of Way (PRoW) are mainly limited to the western section of this part of the Proposed Scheme around the Ruislip Golf Course and between Breakspear Road South and Harvil Road, to the north of the Marylebone to Aylesbury Line.

9.4.5 There are no registered parks or gardens within the study area, although there are conservation areas at Ickenham village, Ruislip Village; and Ruislip Manor Way; numerous listed buildings are located across the area and the Bayhurst Wood Country Park is located to the north west of Ruislip Golf Course. Landscape character assessment

9.4.6 Landscape character areas (LCAs) are defined as areas with broadly homogenous characteristics and are influenced by national and district published character assessments. The Proposed Scheme in this area is located within the Ruislip Plateau and Barnet Plateau (London’s Natural Landscape Areas 2 and 3) as defined in the London Regional Landscape Framework: Natural England, January 201140. For the purposes of this assessment the study area has been sub-divided into seven discrete LCAs two of which are most likely to be affected.

9.4.7 Ruislip Golf Course LCA, an established municipal golf course and driving range and Harefield Farmland LCA, largely pasture with areas of woodland have a high sensitivity.

40 London’s Natural Signature, The London Regional Landscape Framework: Natural England, January 2011.

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Visual baseline

9.4.8 Viewpoints, split into residential, recreational, transport and employment have been selected to represent groups of receptors within the study area.

9.4.9 Residents near the route have a high sensitivity to change. The railway will likely be visible from dwellings close to the existing railway corridor or from a small number of residential towers, located further from the route and looking over the existing Marylebone to Aylesbury Line railway corridor. Views may be possible, to varying degrees, from the more open, rising ground to the west of the study area; however, these would be largely filtered by existing vegetation.

9.4.10 Users of recreational facilities also have a high sensitivity to change in this area. Such people tend to be concentrated along Public Rights of Way through the Ruislip Golf Course to the north of the Marylebone to Aylesbury Line railway corridor and between Breakspear Road South and Harvil Road.

9.4.11 Transport receptors (i.e. users of private or public transport) in the urban area have a low sensitivity to change. There are no known protected views located within the study area. 9.5 Construction Assessment of impacts and mitigation

9.5.1 Due to the scale of the construction activities, works would be highly visible in many locations and would have the potential to give rise to significant effects which cannot be mitigated.This is commonplace with construction of major infrastructure projects, but it should be noted that these effects are temporary in nature and relate to the peak construction phase. Effects during other phases of works are likely to be less, due to less construction equipment being required at the time and a reduced intensity of construction activity.

9.5.2 Measures that have been incorporated into the draft CoCP to avoid or reduce landscape and visual effects during construction include: • Appropriate measures to reduce landscape, visual and other environmental impacts associated with temporary site offices, vehicles, construction plant and compounds, would be implemented; • Avoidance of unnecessary tree and vegetation removal and protection of existing trees in accordance with BS 5837: Trees in relation to design, demolition and construction; • Use of well-maintained hoardings and fencing; • Prevention of damage to the landscape and landscape features adjacent to the construction site by movement of construction vehicles and machinery; • Use of appropriate lighting; and • Appropriate maintenance of planting and seeding works and implementation of management measures, to continue through the construction period as landscape works are completed.

9.5.3 These measures have been taken account of in the assessment of the construction effects in this section. Landscape assessment

9.5.4 The key changes to character as a result of the construction activities, would relate to the presence of construction plant and the demolition of buildings; the construction of the new railway tracks, head house, electricity substation and tunnel portal at West Ruislip to the west

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of Ickenham Road; the vent shaft site located at South Ruislip and the construction compound between Breakspear Road South and Harvil Road to the south of the Marylebone to Aylesbury Line railway corridor. Increases in noise, activity and lighting with a resultant reduction in tranquillity would be most notable in the Harefield Farmland LCA; and there would also be loss of existing vegetation from the Ruislip Golf Course LCA (from the northern edge of the Marylebone to Aylesbury Line railway corridor, from within Ruislip Golf Course and from the Newyears Green Covert to the north of the Marylebone to Aylesbury Line railway corridor).

9.5.5 Table 8 summarises the LCAs that would be significantly affected during construction of the Proposed Scheme.

LCA Sensitivity of Magnitude of Level of effect LCA change to LCA

Ruislip Golf Course LCA High Medium Moderate adverse Construction resulting in loss of vegetation along the golf course boundary, diversion of PRoW, demolition of three buildings and activity associated with tunnel portal construction.

Harefield Farmland LCA High High Major adverse Construction activities associated with the new railway tracks in the cutting, Breakspear Road South junction, demolition of 12 buildings, partial loss of Newyears Green Covert, works associated with diversion of OHL, presence of construction compound between Breakspear Road South and Harvil Road.

Table 8: Significant landscape effects during construction Visual assessment

9.5.6 The most apparent changes to views during construction relate to the presence of construction plant around the vent shaft, tunnel portal and construction compound sites, the presence of the construction site compound between Harvil Road and Breakspear Road South and the presence of new built elements including the new railway embankment in the golf course and cutting east of Harvil Road.

9.5.7 In addition loss of existing vegetation from the northern edge of the Marylebone to Aylesbury Line railway corridor adjacent to Ruislip Golf Course and Newyears Green Covert; and the vent shaft head house and tunnel portal would be visible from the nearby residential and recreational receptors.

9.5.8 The height of the construction plant, and the close proximity of construction activities to viewpoints around tunnel portal and construction compound sites, would result in significant visual effects during construction.

9.5.9 An assessment of effects arising from lighting during construction where( required) will be prepared and included as part of the formal ES.

9.5.10 Table 9 summarises the views which would be significantly affected by the construction of the Proposed Scheme. The numbers in brackets identify the viewpoint locations which are shown on maps LV-11-07 and LV-11-08. The assessed level of effect is considered to be the maximum level at the height of construction activity in the view at each location. The duration of this effect would in most instances be less than the entire construction period and will be considered in the formal ES. An indicative construction programme is set out in Section 2 of this report.

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Viewpoint Sensitivity Magnitude Level of effect to of visual of change visual receptors receptors

Residential receptors

View north from Trenchard Avenue and Portal Close (041.2.001) High Medium Moderate adverse Visibility of cranes and other construction plant behind the line of boundary trees.

View west from tower block on Josiah Drive at Ickenham Park, south of High Medium Moderate adverse the West Ruislip Station (up to six storeys) (045.2.004) Middle and background views of activities associated with construction of tunnel portal and head house and loss of vegetation along the Marylebone to Aylesbury Line.

View north from The Greenway; view from Ickenham Close, Ickenham High Medium Moderate adverse Road and south from the Blenheim Care Centre; view north from Hoylake Crescent, from King George V Playing Field, from PRoW and Ickenham Cricket Club Ground (045.2.005 and 046.2.002 and 047.2.002) Middle and background views of activities associated with construction of tunnel portal and head house.

View north from Brackenbury Farm, scheduled monument moat off High Medium Moderate adverse Breakspear Road, Ickenham (047.2.005) Middle-ground views of construction activities associated with the new embankment, Breakspear Road junction and construction compound to the west.

View west from Breakspear Road South and Swakeleys Road; and view High Low Moderate adverse west from Breakspear Road South and Copthall Farm (047.2.004 and 047.2.006) Middle-ground views of the construction compounds, partially screened by intervening vegetation.

View south from Square Orchard and associated properties (048.2.005) High Low Moderate Background views of the works associated with construction of new tracks adverse and loss of embankment vegetation.

View north-east from Harvil Road (049.2.007) High High Major Foreground and middle-ground views of construction activities associated adverse with the upgrade of junction at Harvil Road, cutting, partial loss of Newyears Green Covert and views of the construction compound to the south of Marylebone to Aylesbury Line.

Recreational receptors

View south-west from Ruislip Golf Course Club House (046.3.004) High High Major adverse Foreground views of activities associated with construction of tunnel portal and head house, loss of existing vegetation.

View south from the two PRoW across Ruislip Golf Course (046.3.006 High Medium Moderate adverse and 048.3.003) Middle and background views of activities associated with construction of tunnel portal and head house, loss of existing vegetation.

View east from PRoW near Harvil Road (49.3.006) High High Major adverse Foreground and middle-ground views of construction activities associated with the new tracks in cutting, partial loss of Newyears Green Covert and views of construction compound to the south of Marylebone to Aylesbury Line.

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Viewpoint Sensitivity Magnitude Level of effect to of visual of change visual receptors receptors

Transport receptors

View north and north-west from West Ruislip Station (045.4.003) Low Medium Moderate adverse Middle and background views of activities associated with construction of tunnel portal and head house and loss of vegetation along the Marylebone to Aylesbury Line.

Employment receptors

View south from Harvil Road Dog Trust Harefield including Highway Low High Major adverse Farmhouse Grade II Listed (052.6.003) Middle-ground views of the construction activities associated with the Colne Valley viaduct southern approach embankment which would be approximately 90m long. Beyond this is the location of the southern approach site compound and associated plant. Also within the view is the demolition of the Hillingdon outdoor activities centre.

Table 9: Significant visual effects during construction Likely residual significant effects

9.5.11 Due to the close proximity of visual receptors to construction activities along the Proposed Scheme there would be significant residual effects as set out in Table 9 above, although they would be temporary and reversible in nature, lasting only for the duration of the construction works. Residual effects would generally arise from the foreground visibility of construction activity and temporary construction features from residential receptors, PRoW and travellers on roads in the study area. Further mitigation

9.5.12 Further measures currently being considered but which are not yet part of the design include: • Minimising land take to reduce impacts on trees and other vegetation and to allow new and replacement planting of trees lost during construction; • Creation of screening bunds along Harvil Road and either side of Shorthill Cottage to reduce the visual impact of the construction site compound; and • New planting could be provided on the land used temporarily for construction of the tunnel portal and along the embankment/cutting. 9.6 Operation Assessment of impacts and mitigation

9.6.1 The operational assessment of impacts and mitigation measures is based on the first year of opening of the Proposed Scheme (2026). A process of iterative design and assessment has been employed to avoid or reduce adverse effects during the operation of the Proposed Scheme. A measure that has been incorporated into the design of the Proposed Scheme includes designing the structures associated with the vent shaft and tunnel portal buildings to be as small as practicable.

9.6.2 This measure has been taken account of in the assessment of the operation effects.

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Landscape assessment

9.6.3 The potential significant effects on the landscape in 2026 (i.e. the assumed year of opening) occur within the same LCAs experiencing effects during construction. Effects on LCAs would relate to the presence of new structures/elements in the landscape including: the tunnel portal at West Ruislip including a 60m by 30m head house, up to 13m high; the road junction realignment at Breakspear Road South and Harvil Road; the relocation of overhead line equipment; the presence of a large cutting to accommodate the route, permanent severance of land and the introduction of regular high speed trains.

9.6.4 Table 10 summarises the LCAs that would be significantly affected by the Proposed Scheme in year one of operation (2026).

LCA Sensitivity Magnitude Level of effect to of LCA of change LCA41

Ruislip Golf Course LCA High Medium Moderate adverse Presence of the Proposed Scheme, lack of screening vegetation, severing golf course.

Harefield Farmland LCA High Medium Moderate adverse Presence of the Proposed Scheme, particularly the cutting, lack of screening planting of Newyears Green Covert, severing agricultural land.

Table 10: Significant landscape effects during operation year 1 (2026)41 Visual assessment

9.6.5 The potential significant effects on views in 2026 (i.e. the assumed year of opening) are applicable to fewer viewpoints than those considered to be affected during construction.

9.6.6 The most apparent changes to views would be for residents and recreational users in close proximity to the new railway embankment/cutting, tunnel portal head house and where the removal of existing vegetation from the Ruislip Golf Course and Newyears Green Covert would open up views of the new infrastructure. Replacement planting, where agreed, would not be sufficiently established in year one to provide substantial screening.This screening potential would increase over time as planting increases in height and matures. There would be no substantial change to the assessment during summer although the existing vegetation associated with the golf course would provide denser screening elements.

9.6.7 Photomontages have been produced illustrating the view of the Proposed Scheme during operation year 1 from viewpoints 049.2.007, on Harvill Road (figure LV-12-17), and 045.4.003, from Ickenham Road Bridge (figure LV-12-18).

9.6.8 Table 11 summarises the visual receptors that would be significantly affected by the Proposed Scheme in year one of operation (2026). The numbers in brackets identify the viewpoint locations which are shown on maps LV-11-07 to LV-11-08.

41 In year one of operation, any new planting along the Proposed Scheme would be immature and therefore not help to integrate the Proposed Scheme into the landscape. As the plants mature, screening of the Proposed Scheme would improve.

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Viewpoint Sensitivity Magnitude Level of effect to of visual of change visual receptors42 receptors

Residential receptors

View north from Trenchard Avenue and Portal Close (041.2.001) High Low Moderate Visibility of the vent shaft head house above the existing railway adverse vegetation.

View from tower block on Josiah Drive at Ickenham Park, south of the High Medium Moderate West Ruislip Station (up to six storeys) (045.2.004) adverse Middle ground visibility of the Proposed Scheme and lack of vegetation to the south of golf course.

View north east from Harvil Road (049.2.007) High Medium Moderate Foreground and middle ground views of the new junction of Harvil road, adverse cutting and lack of vegetation at Newyears Green Covert.

Recreational receptors

View from Ruislip Golf Course Club House; View from the two PRoW High Medium Moderate across Ruislip Golf Course and from Ruislip Golf Course (046.3.004, adverse 046.3.006 and 048.3.003) Foreground and middle ground views of the Proposed Scheme, diverted overhead line and lack of screening vegetation along the southern boundary of the golf course.

View east from PRoW near Harvil Road (049.3.006) High Medium Moderate Foreground and middle ground views of the Proposed Scheme, diverted adverse OHL and lack of screening vegetation along the southern boundary of the golf course.

Employment receptors

View south from Harvil Road Dog Trust Harefield including Highway Low Medium Moderate Farmhouse Grade II Listed (052.6.003) adverse Middle ground views of the southern approach embankment and viaduct over River Colne, partially screened by roadside hedgerows.

Table 11: Significant visual effects during operation year 1 (2026)42

9.6.9 Where planting has been proposed, effects in year 15 (2041) and 60 (2086) of operation would be reduced compared to year one (2026), due to the increased height and maturity of trees. An assessment of effects for these assessment years will be prepared and presented within the formal ES. Likely residual significant effects

9.6.10 Due to the highly sensitive nature of the landscape and visible nature of the Proposed Scheme, significant residual effects would remain, as set in Table 10 and Table 11 above. The residual effects would arise from a local change in character in the vicinity of the Proposed Scheme and the foreground visibility of the proposed head house and viaduct from residential and recreational receptors. Further mitigation

9.6.11 The further measures identified below would reduce the adverse effects on landscape character and visual amenity by helping to integrate the Proposed Scheme into the surrounding landscape.

42 In year one of operation, any new planting along the Proposed Scheme would be immature and therefore not help to integrate the Proposed Scheme into the landscape. As the plants mature, screening of the Proposed Scheme would improve.

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9.6.12 Retaining existing vegetation, where reasonably practicable, through minimising the land take for construction and subsequently operation would help to screen sensitive residential and recreation receptors. If the retention of planting is not possible, the new replacement vegetation would create a new screening element once established.

9.6.13 Further measures currently being considered but which are not yet part of the design include: • Minimising temporary and permanent land take for the construction sites, shaft site, head house and tunnel portal; • Designing the appearance of the head house and the electricity substation to be in keeping with the character and scale of the surrounding properties by using local materials appropriate to the local vernacular style; • Designing fencing and other boundary treatments to reduce adverse effects on the landscape character and setting of visual receptors in the immediate surroundings of the tunnel portal; • Minimising hard standing around the tunnel portal and shaft sites; • Utilising the minimum security fencing possible by designing secure buildings to reduce visual intrusion and maximise replanting areas; • Reinstating planting along the southern boundary of Ruislip Golf Course where reasonably practicable and exploring the possibility of changing the landform on the southern edge of the Ruislip Golf Course using excavated material from the construction in order to create a more natural embankment profile and varied landform for the golf course. New areas would be planted where reasonably practicable, in line with the golf course layout; and • Reinstating planting adjacent to Newyears Green Covert particularly on the cutting, where reasonably practicable.

72 CFA Report – South Ruislip to Ickenham/No 6 I Socio-economics 10 Socio-economics 10.1 Introduction 10.1.1 This section provides a summary of the assessment methodology and scope, environmental baseline, and likely significant economic and employment effects during construction and operation of the Proposed Scheme.

10.1.2 The need generally for a socio-economic assessment results from the potential for the Proposed Scheme to affect: • Existing businesses and community organisations and thus the amount of local employment; • Local economies, including employment; and • Planned growth and development.

10.1.3 The beneficial and adverse socio-economic effects of the ProposedScheme are reported at two different levels: route-wide and CFA. Effects on levels of employment are reported at a route-wide level within Report 27 (Route-wide effects). Localised effects on businesses and observations on potential local economic effects are reported within eachCF A report. 10.2 Policy framework 10.2.1 The planning policy documents (and their status) applicable to the area are described in Sections 2.1.24-2.1.29. 10.3 Assessment scope and key assumptions 10.3.1 The assessment scope and key assumptions for the socio-economic assessment is set out in Volume 1. 10.4 Environmental baseline 10.4.1 Section 2.1 provides a general overview of the area which includes data of specific relevance to socio-economics notably demographic data and employment data. The following provides a brief overview in terms of employment, economic structure, labour market, and business premises available within the area.

10.4.2 The South Ruislip to Ickenham CFA is entirely within the LBH. Around 370,000 people work in LBH with an employment rate of 65% (which represents 130,000 people), in line with London and England figures (65%) and highlighting the very high level of inward commuting43,44,45. As of September 2012, the unemployment rate for LBH stood at 10% compared to the England average of 8%46. With 28% of LBH residents aged 16 and over qualified to National Vocational Qualification Level 4 (NVQ4) the area compares poorly to London (38%) but is in line with England (27%). Whilst 13% had no qualifications, this was better than that recorded both for London (18%) and England (23%)47.

10.4.3 Within LBH there is a wide spread of business types reflecting a diverse range of commercial services. The professional, scientific and technical services sector accounts for the largest proportion of businesses (13%), with the construction (12%), and retail (11%) sectors also accounting for relatively large numbers of businesses within the borough. This is shown in

43 Office for National Statistics (ONS) (2012), Business Register and Employment Survey 2011. 44 The proportion of working age (16-74 years) residents that is in employment. 45 ONS (2012), Census 2011. 46 ONS (2012), Annual Population Survey. 47 ONS (2012), Census 2011.

73 CFA Report – South Ruislip to Ickenham/No 6 I Socio-economics

Figure 448. For comparison within the London region the professional, scientific and technical services sector accounts for the largest number of businesses (20%), with the information and communication (11%), retail (10%) and arts, entertainment, recreation and other services (8%) sectors also accounting for relatively large numbers of businesses within the region49.

Retail

Professional, scientific & technical

Construction

Health

Business administration and support services

Production

Accommodation & food services

Arts, entertainment, recreation and other services

Wholesale

Information & communication

Birmingham Other West Midlands 0% 5% 10%15% 20% 25%

Figure 4: Business Sector Composition in LBH and London

Source – Office for National Statistics (2011), UK Business: Activity, Size and Location50

10.4.4 Data for quarter 3 of 2012, published by Jones Lang LaSalle, indicated that 10% of the 7.6 million m2 (around 82 million ft2) of industrial and warehousing floorspace in West London was vacant51. In LBH itself total industrial/warehousing stock is estimated to be 1.3 million m2 (14 million ft2). There is no known recent floorspace vacancy rate available for industrial/ warehousing in the borough although the vacancy rate (for office and industrial units) in008 2 was estimated to be moderately high, at around 14%, within designated employment sites52. 10.5 Construction Assessment of impacts and effects

10.5.1 Businesses directly affected, i.e. those that lie within land which would be acquired for the construction of the Proposed Scheme, are reported in groups where reasonably practicable to form defined resources, based on their location and operational characteristics.A group could contain either one or a number of businesses.

10.5.2 Construction of the Proposed Scheme would impact the agricultural research facility at Breakspear Road South in LBH. Given the specialist nature of the site, finding an alternative location within the local area would be more difficult than for a standard office or industrial occupier. This will be considered in more detail during the preparation of the formal ES.

48 Figure 4 presents the proportion of businesses within each business sector in the borough but not the proportion of employment by sector. 49 ONS (2011), UK Business: Activity, Size and Location. 50 ‘Other’ includes Agriculture, Forestry &Fishing; Production; Motor Trades; Finance and Insurance; Property; Public Administration and Defence; and Education and Health sectors. 51 Jones Lang LaSalle (2012), The Western Corridor Industrial and Warehouse Market Report (September 2012). 52 LBH (2009), London Borough of Hillingdon Employment Land Study.

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10.5.3 It is estimated that the Proposed Scheme would result in the displacement or possible loss of a total of up to 230 jobs53 within this area. Taking into account the availability of alternative premises and the relatively healthy local economy, the displacement or possible loss of jobs is considered to be relatively modest compared to the scale of economic activity and opportunity in the area.

10.5.4 There are plans to locate construction compounds for the Proposed Scheme at the following locations within the area: • South Ruislip ventilation shaft main site; • West Ruislip tunnel portal main site; • Between Breakspear Road South and Harvil Road in West Ruislip main site; • Diversion of Ickenham Stream to River Pinn and footbridge south of Ruislip Golf Course satellite site; • Retained embankment south of Ruislip Golf Course and continuing directly west of Breakspear Road South satellite site; • River Pinn underbridge satellite site; • Breakspear Road South underbridge satellite site; • Cutting north of Marylebone to Aylesbury Line between Breakspear Road South and Harvil Road satellite site; • Harvil Road realignment satellite site; • Harvil Road bridge over Newyears Green Bourne satellite site; • Harvil Road bridge over Marylebone to Aylesbury Line; and • Harvil Road bridge over the Proposed Scheme.

10.5.5 The use of these sites could result in the creation of up to 2,900 person years of construction employment that, depending on skill levels required and the skills of local people, are potentially accessible to residents in the locality and to others living further afield54. It could also lead to opportunities for local businesses to supply the project or to benefit from expenditure of construction workers. Quantification of direct and indirect construction employment effects are captured at a route wide level (see Report 27 (route-wide effects).

10.5.6 It is intended that discretionary enhancement measures, such as business support, supply chain engagement and local construction skills development initiatives to enhance local business performance will be included as appropriate in the formal ES. Likely residual significant effects

10.5.7 The likely residual significant socio-economic effects are currently being assessed and will be reported in the formal ES.

53 Employment within businesses has been estimated through a combination of sources, for example, surveys of businesses, the Experian employment dataset, employment floorspace and the Homes and Communities Agency (HCA) Employment Densities Guide (2010).The estimate is calculated using standard employment density ratios and estimates of floor areas and may vary significantly from actual employment at the sites. 54 Construction labour is reported in construction person years, where one construction person year represents the work done by one person in a year composed of a standard number of working days.

75 CFA Report – South Ruislip to Ickenham/No 6 I Socio-economics

10.6 Operation Assessment of impacts and mitigation

10.6.1 The Proposed Scheme would create direct and wider operational employment opportunities at locations along the route including stations, train crew facilities and infrastructure/ maintenance depots. Although no plans exist to locate these facilities within this area it is considered possible that wider operational employment opportunities could be accessed by residents of the area. Operational effects are captured and assessed at a route wide level (see Report 27 (route-wide effects)). Likely residual significant effects

10.6.2 The likely residual significant socio-economic effects are currently being assessed and will be reported in the formal ES.

76 CFA Report – South Ruislip to Ickenham/No 6 I Sound, noise and vibration 11 Sound, noise and vibration 11.1 Introduction 11.1.1 This chapter provides a summary of the likely noise and vibration significant effects associated with the construction and operation of the Proposed Scheme for the South Ruislip to Ickenham area. This chapter should be read in conjunction with Volume 1. 11.2 Policy framework 11.2.1 The policy framework for sound, noise and vibration is set out in Volume 1. 11.3 Assessment scope and key assumptions 11.3.1 The approach to the assessment of sound, noise and vibration and the related key assumptions are set out in Volume 1, with local variations as described below. A summary of the operating assumptions is given in section 2.4 of this report.

Assumptions 11.3.2 In addition to those given in Volume 1 and section 2.4 of this report, the following assumptions apply to the assessment of sound noise and vibration in this area: • Tunnel Boring Machines (TBMs) would be used to excavate the tunnels. It has been assumed that materials (including tunnel lining segments), people and equipment would be transported from the surface to the TBM using small construction trains, which would travel at relatively low speeds. It has been assumed that significant noise and vibration effects arising from use of the temporary railway would be avoided by a design and maintenance specification; • The engineering design of tunnels and their portals will ensure passenger comfort in tunnels. This design should also avoid any significant airborne noise effects caused by the tunnel portals. This will be confirmed in the formal ES; and. • Tunnel ventilation shafts and tunnel portals are likely to include mechanical ventilation equipment. This equipment would only operate in abnormal situations or in the event of an emergency. It is assumed that the ventilation equipment in the vent shafts would be designed so it could be tested, like that associated with HS1, during the daytime. This is subject to on-going development work that will be reported in the formal ES.

11.3.3 It has been assumed that significant noise effects from the operation of tunnel ventilation shafts and static equipment (e.g. auto-transformers) would be avoided through the design and specification of the shafts and any fixed plant and equipment.

11.3.4 Passenger services have been assumed to operate at 320kph in this area.

11.3.5 For the operational railway, it is assumed that ground-borne noise and vibration would be mitigated at source in so far as is reasonably practicable. A particular assumption is that optimised low vibration slab track is installed (equivalent to that installed in HS1 London tunnels). It is also assumed that the maintenance regime would be specified to reduce noise and vibration.

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11.4 Environmental baseline 11.4.1 The baseline sound environment for this area where the alignment is at the surface near Ickenham is typical for a suburban location with levels increasing close to roads, especially Breakspear Road South and Ickenham Road (B466) adjacent to West Ruislip Station. The existing rail corridor is also a significant noise source carrying Marylebone toAylesbury Line freight services (the freight services operating intermittently through the night). Properties on the southern edge of West Ruislip (in the general area of Hoylake Crescent) are located at some considerable distance from the major existing sound sources and hence existing sound levels are quite low for a suburban location. Aircraft are regularly heard in this area but aircraft sound is not the dominant source in these areas.

11.4.2 The baseline environment around the vent shaft site at South Ruislip is typical for an urban situation, with existing levels determined by the nearby Marylebone to Aylesbury Line and freight services, and local road traffic movements.

11.4.3 It is likely that the majority of receptors adjacent to the line of route are not currently subject to appreciable vibration. Baseline monitoring to be undertaken for the formal ES will confirm, as necessary, whether this is the case for receptors close to existing railways. For the draft ES, vibration at all receptors has been assessed using the absolute vibration criteria as described in Volume 1. 11.5 Construction Assessment of effects and mitigation

11.5.1 This initial assessment has considered the potential effects on community receptors within the study area, their occupants and their use (including annoyance and activity disturbance) arising from construction noise and/or vibration.

11.5.2 The mitigation measures specified within the draft CoCP have been included within the assessment of construction noise and vibration.

11.5.3 TBMs would be used to excavate the tunnels. The tunnel drives are proposed to be launched and supported from West Ruislip. Each TBM would be likely to generate ground-borne noise and vibration impacts but only at receptors within a close distance of the centre line of the tunnels and only for short periods of time (a few days). Overall, the deeper the tunnel the lower the impact. The perceptible noise and vibration would increase as each TBM approaches and diminish as it moves away from the receptor. It has been assumed that the two drives would be staggered in time so there would be no combined effect from the twoTBMs. Vibration from TBMs would present no risk of any building damage.

11.5.4 The effects of vibration from TBMs on building occupants would be short term (a matter of days) and hence they are not considered to be significant. Proactive and advanced community relations in advance of the TBM passing under properties would help manage expectations and allay possible concerns over the short term presence of vibration.

11.5.5 Potential construction noise or vibration effects could occur on the receptors closest to the construction areas in the following communities: • Hoylake Crescent and Breakspear Road South during daytime works for River Pinn underbridge and Breakspear Road South underbridge and line of route construction activities (refer to Section 2.2/2.3 and to maps CT‑05 Construction features);

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• The Greenway, Tile Kiln Lane, Old Priory, Field Way, Hill Rise, Glenhurst Avenue and Ickenham Close during the tunnelling support activities which are required to operate continuously (24 hours a day) through the construction of the tunnels (refer to Section 2.2/2.3 and to maps CT‑05 Construction features); and • Trenchard Avenue, during the construction of the tunnel ventilation shaft (refer to Section 2.2/2.3 and to maps CT‑05 Construction features).

11.5.6 Track laying, power system and signalling installation works along the line of route are unlikely to result in significant construction noise effects, given the short duration close to any communities and the presence of the permanent noise barriers. Likely residual significant effects

11.5.7 Further work is being undertaken to confirm significant construction noise and vibration effects, including any temporary effects from construction traffic. Non-residential receptors identified at this stage as potentially subject to construction noise or vibration effects will be further considered, where necessary, on a receptor-by-receptor basis. Any further assessment will be reported in the formal ES. Further mitigation

11.5.8 Further work is being undertaken to confirm the likely significant effects and identify any site‑specific mitigation considered necessary in addition to the general measures set out in the draft CoCP. Any site-specific mitigation will be presented in the formal ES and will include an estimate of the number of properties that may qualify for noise insulation or temporary re‑housing under provisions set out in the draft CoCP. 11.6 Operation Assessment of effects and mitigation

11.6.1 This initial assessment has considered the potential effects on community receptors within the study area, their occupants and their use (including annoyance, activity and sleep disturbance) arising from operational noise and/or vibration. Further assessment will be undertaken for the formal ES.

11.6.2 The on-going development of the scheme includes noise barriers in the form of landscape earthworks, noise (fence) barriers and/or low level barriers on viaducts. The envisaged noise barrier locations are shown on the Operational Sound Contour and Potential Significant Effect Maps SV-01.

11.6.3 The Operational Sound Contour and Potential Significant Effect Maps SV-01 indicate the likely long-term daytime sound level (defined as the equivalent continuous sound level from 07:00

to 23:00 or LpAeq,day) from HS2 operations alone. The contours are shown in 5dB steps from 50dB to 70dB. With the train flows described in Volume 1, the night-time sound level (defined

as the equivalent continuous sound level from 23:00 to 07:00 or LpAeq,night) from the Proposed

Scheme would be approximately 10dB lower than the daytime sound level. The 50dB contour therefore indicates the distance from the Proposed Scheme at which the night-time sound level would be 40dB. This contour represents where the lowest observed community noise effects would be expected to occur during the day (with respect to annoyance) and night (with respect to sleep disturbance). It is generally unlikely that there would be any adverse noise effects outside of this contour. With regard to sleep disturbance the assessment has also taken account the maximum sound levels generated by each train pass-by.

79 CFA Report – South Ruislip to Ickenham/No 6 I Sound, noise and vibration

11.6.4 Residential receptors within the daytime 65dB contour, and therefore the night-time 55dB contour, have been identified as being likely to experience a significant adverse effect from HS2 noise alone. This is in line with the daytime threshold for in the Noise Insulation Regulations and the interim target defined in the World Health Organization’s Night Noise Guidelines55,56.

11.6.5 The potential for significant noise effects on communities in areas between the0dB 5 and 65dB daytime sound contours, or 40dB and 55dB night-time contours, will be dependent on the baseline in that area and the change in sound level brought about by the Proposed Scheme.

11.6.6 For the draft ES, the criteria used in assessing whether an effect is potentially significant includes factors such as the number and magnitude of impacts in a community as well as the existing sound environment. The further significance criteria set out in Volume 1, including the character of the existing sound environment, any unique features of the Proposed Scheme’s sound or impacts, and the potential combined impacts of sound and vibration will be taken into account in the formal ES.

11.6.7 This initial assessment has identified potential airborne noise effects on the following non- residential receptors and land uses (e.g. schools, hospitals, hotels): • Dogs Trust offices, Denham (identified by SV06-N01 on maps SV-01); and • Schering-Plough (MSD) Animal Health Ltd (identified by SV06-No2 on maps SV-01).

11.6.8 By their nature, PRoW are transitory routes, with users not staying in any one location for long periods. Train sound from the Proposed Scheme is intermittent and its level at the PRoW would vary as the PRoW is closer to and further from the Proposed Scheme. Noise effects would generally be reduced by the landscape earthworks envisaged to reduce visual impact of the scheme and envisaged noise mitigation to protect other receptors. No significant noise effects have therefore been identified on PRoW within this area.

11.6.9 No potentially significant noise or vibration effects arising from changes to existing roads are anticipated at this stage. This will be confirmed in the formal ES.

11.6.10 A number of potential minor ground-borne noise and vibration impacts have been forecast at a small number of properties very close to the alignment/tunnels. Taking account of the number and minor magnitude of the impacts, and the experience of HS1, no significant effects have been identified. Further assessment will be undertaken for the formal ES to confirm whether the impacts currently forecast are likely to occur. Vibration from the operation of the Proposed Scheme would present no risk of any building damage.

11.6.11 This initial assessment has identified potential ground-borne noise and vibration effects on the following non-residential receptors and land uses (e.g. schools, hospitals, hotels): • Blenheim Care Centre on Ickenham Road; and • The Days Inn Hotel on Long Drive in Ruislip.

55 The Noise Insulation (Railways and Other Guided Transport Systems) Regulations, 1996. London, Her Majesty’s Stationery Office. 56 World Health Organization (2009), Night Noise Guidelines for Europe.

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Likely residual significant effects

11.6.12 The envisaged mitigation (especially landscape earthworks and noise fence barriers) described in this chapter substantially reduces the potential airborne sound impacts and noise effects that would otherwise arise from the Proposed Scheme. Nonetheless, potential significant adverse airborne noise effects have been identified for residential receptors in the north western part of Ickenham community in the general vicinity of Hoylake Crescent, Pynchester Close, Bushy Road, The Greenway and Copthall Close West (identified by SV06-C01 on maps SV-01).

11.6.13 Further assessment work is being undertaken to confirm operational sound and vibration significant effects, including those at non-residential receptors and quiet areas (as necessary on a receptor-by-receptor basis). This will be reported in the formal ES which will present baseline levels, forecasts for the Proposed Scheme and the change in sound levels brought about by the Proposed Scheme both as impact plans and tables. Further mitigation

11.6.14 Improved mitigation performance is required which can be achieved by the suggestions given in Table 12:

Potential significant effect Further mitigation option

North Western edge of Relocate proposed noise (fence) barrier on the south side of the Proposed Scheme, or equivalent, Ickenham such that it is on the south side of the existing rail corridor or provide noise barriers on the south (SV06-C01) side of the Proposed Scheme and the existing rail corridor.

Table 12: Options for further mitigation

11.6.15 The suggested further mitigation options would reduce or avoid the potential significant airborne noise effect at these locations.

81 CFA Report – South Ruislip to Ickenham/No 6 I Traffic and transport 12 Traffic and transport 12.1 Introduction 12.1.1 This traffic and transport section describes the likely transport effects on all modes arising from the construction and operation of the Proposed Scheme within the South Ruislip to Ickenham area. 12.2 Policy framework 12.2.1 Within the South Ruislip to Ickenham area, the relevant regional and local policy documents comprise The London Plan 2011, the Mayor’s Transport Strategy, LBH Local Implementation Plan, LBH Local Plan and emerging Local Development Framework57,58,59.

12.2.2 The London Plan 2011 sets out the strategic planning guidance for London planning authorities over the next 20-25 years and has a number of policies of relevance to the Proposed Scheme including Policies 6.1 and 6.4. These note that public transport capacity should be increased by exploring the scope for high speed rail services.

12.2.3 The Mayor’s Transport Strategy sets out the Mayor’s vision for London and describes how Transport for London (TfL) and its partners, including the London boroughs, will deliver that vision. The Mayor’s Transport Strategy sets out a number of overarching transport priorities and contains a number of policies relevant to the Proposed Scheme. These policies include the following points of reference; 5.2 ‘Proposals to manage and enhance the transport system – National Rail, Crossrail, Thameslink, London Overground, DLR and Tramlink’ which sets out the Mayor and TfL’s support for the Proposed Scheme and 5.3.4 ‘Station Congestion Relief’ which supports the development of major strategic multi-modal/National Rail interchanges to disperse onward demand arising from HS2 proposals.

12.2.4 LBH’s Local Implementation Plan (LIP) sets out how the Council proposes to implement the Mayor’s Transport Strategy (MTS) and provides details on projects, proposals and programmes through to 2014. The LIP underwent consultation between January 2011 and March 2011.

12.2.5 LBH Local Plan: Part 1- Strategic Policies was approved for adoption in 2012. It sets out the key elements of the planning framework for the borough over the next 15 years. Together with extant 2007 Saved Unitary Development Plan policies (adopted as the LBH Local Plan: Part Two) and the London Plan, these documents currently make up the development plan for the borough. Relevant policies include references to Annual Monitoring and Local Plan Review to identify adverse effects of HS2. The Council intends to prepare and consult on Part 2 of the LBH Local Plan in 2013.

12.2.6 The Hillingdon Design and Accessibility Statement Supplementary Planning Document (SPD) on Transport Interchanges sets out design principles for transport interchanges within Hillingdon60. The emerging policy baseline will be available as part of the formal ES. 12.3 Assessment scope and key assumptions 12.3.1 The scope and methodology of the traffic and transport assessment is set out inVolume 1.

57 Mayor of London (2010), Mayor’s Transport Strategy. London, Greater London Authority. 58 London Borough of Hillingdon (2011), London Borough of Hillingdon Local Implementation Plan 2011 – 2014. 59 London Borough of Hillingdon (2012), London Borough of Hillingdon Local Plan: Part 1 Strategic Policies. 60 London Borough of Hillingdon (2006), Hillingdon Local Development Framework Planning and Transportation Group, Hillingdon Design and Accessibility Statement Supplementary Planning Document.

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12.3.2 It should be noted that the transport and passenger modelling of HS2 is continuing to be developed and therefore the assessment will be updated for the formal ES.

12.3.3 The impact of construction has been assessed on the assumption that all excavated material from the worksites would be removed by road, although investigation will continue to establish the possibility of movement by rail. The construction traffic assessment will be updated for the formal ES.

12.3.4 There have been certain scheme design changes following the initial transport assessment work, which have not yet been incorporated into the draft ES. These include: • The boundary between this CFA and the adjacent Colne Valley CFA has been moved westwards; and • A planned railhead at Harvil Road for transportation of excavated and other materials. The impact of construction road traffic has been assessed. The assessment of construction impacts assumes a worst-case scenario that all excavated material from the worksites would be removed by road.

12.3.5 The following key limitations exist in the reporting of significant effects: • The operation effects of the Proposed Scheme on buses have not been assessed to date, although at this stage it is not expected that demand generated by the operation of the Proposed Scheme within this CFA would be sufficient to have a significant impact on existing public transport services in the area; and • The assessment has addressed all Volume 1 criteria except for the effects on rail network and services which can only be determined at a more detailed stage.

12.3.6 A number of transport modelling tools have been used to inform the assessment including TfL’s Railplan model and WeLHAM (West London Highway Assignment Model) for public transport and highways respectively. At this stage, the assessment covers the typical 0800- 0900 morning peak periods for an average weekday.

12.3.7 Within this CFA, only limited traffic flow information consisting of sample manual counts (non- classified and excluding cyclists) has been obtained at this stage.These counts currently do not include Breakspear Road South and Harvil Road for which earlier WeLHAM traffic model data has been used.

12.3.8 Due to the semi-rural nature of Breakspear Road South and Harvil Road, parking surveys were not conducted in these areas as no significant impacts were anticipated.

12.3.9 The diversionary effects of potential utilities diversions or strengthening works have not been identified or assessed and will be reported in the formal ES. 12.4 Environmental baseline 12.4.1 A combination of desktop research and observational traffic and transport surveys have been undertaken in order to understand the 2012 baseline transport situation within the vicinity of the construction site compounds in the South Ruislip to Ickenham area.

12.4.2 Existing conditions have been determined through site visits, specially commissioned transport surveys and liaison with TfL and other stakeholders to source transport models and accident data. All transport modes have been surveyed including private vehicles, public transport, walking, cycling and taxis, with the data supplemented by information from TfL.

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12.4.3 Proposed worksites in the area would be generally located parallel to, and to the north of the A40 Western Avenue. The M25 lies around 4.5km to the west of the Harvil Road site and the M40 junction 1 a little over 2km to the south. The majority of the highway network in the area consists of urban residential streets, with the exception of Breakspear Road South and Harvil Road which are semi-rural in nature. For further details of the major road network in the area, refer to map CT‑02-INDEX-CFA6.

12.4.4 Parking demand surveys of streets in the vicinity of the proposed vent shaft main site at South Ruislip suggest that weekday morning peak demand during 0900-1000 is over-capacity on Victoria Road, in the vicinity of the proposed vent shaft access road. Demand for parking in streets near the tunnel portal main site at West Ruislip over the same period remained within capacity except for The Greenway which reached over-capacity. Surveys indicate approximately 6,000 passengers per day (two-way) at each of the South Ruislip and West Ruislip Stations.

12.4.5 Sample traffic counts for a typical weekday morning peak period from 0800 to 0900 recorded approximately 600 two-way vehicle movements passing the proposed vent shaft site access at South Ruislip on Victoria Road. Traffic counts on Ickenham Road for a similar period recorded approximately 1400 vehicles two-way past Hill Lane junction. 2009 WeLHAM baseline model flows suggest approximately 1300 two-way vehicles use the busiest section of Breakspear Road South in the 0800-0900 morning peak period. The same data suggests that approximately 800 two-way vehicles use Harvil Road during the same time period.

12.4.6 There are no bus routes or stops in the Breakspear Road South area and Harvil Road has a single bus route (service U9). West Ruislip Underground and Rail station is located on the B466 Ickenham Road, adjacent to the HS2 alignment and approximately 100m to the east of the proposed tunnel portal main site at West Ruislip. South Ruislip Underground and Rail station is located approximately 450m to the east of the proposed vent shaft main site at South Ruislip.

12.4.7 There are no footways in the vicinity of the proposed Breakspear Road South underbridge and footway provision along Harvil Road is minimal. There are several PRoW in the vicinity of the proposed Breakspear Road South main construction site compound and surveys to capture usage levels were undertaken in August 2012. In general, the surveys recorded very low levels of pedestrian activity.

12.4.8 Ickenham Road has advisory cycle lanes in each direction in the vicinity of the site and mandatory lanes in each direction over the railway bridge. Hill Lane provides cycle access across Ruislip Golf Club via a shared pedestrian and cycle path. For details of National Cycle Routes in the area refer to map CT‑02-INDEX-CFA6.The accident data for the 36-month period from April 2009 to March 2012 revealed no accidents in the vicinity of the proposed vent shaft main site at South Ruislip. For the Ickenham Road area, a few clusters of slight accidents were located along the Ickenham Road overbridge adjacent to the proposed tunnel portal main site at West Ruislip and around the Hill Lane junction. At Breakspear Road South, a single slight accident was recorded in the vicinity of the Schering-Plough access. At Harvil road, only one slight accident was recorded on the left hand bend when approaching the existing bridge from the south.

12.4.9 The River Pinn lies approximately 140m to the east of Breakspear Road South. For details of water bodies in the area, refer to map CT‑02-INDEX-CFA6.

12.4.10 The future baseline traffic volumes have been derived from WeLHAM for the future years of 2021, 2026 and 2041. No other changes to the traffic and transport baseline are anticipated in the South Ruislip to Ickenham area.

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12.5 Construction Assessment of impacts and mitigation

12.5.1 The following section considers the impacts on traffic and transport and the consequential effects resulting from construction of the Proposed Scheme.

12.5.2 Within the South Ruislip to Ickenham area, the key construction activities include bridge replacement works, construction of a vent shaft and a tunnel portal. The main impacts during the construction phase relate to changes to the highway network due to construction traffic, road closures and other restrictions which would affect highway vehicles, buses, taxis, cyclists and pedestrians. Although the construction of a tunnel would be disruptive, the measure is mitigation in itself and is intended for the long term benefit of the community.

12.5.3 An initial assessment of construction traffic trip generation has been undertaken for the construction sites within this CFA and expected daily numbers of trips are indicated in Table 13 below. These are subject to change as the design progresses.

Compound Location Access Estimated Typical daily type duration of use number of two-way trips

LGVs and HGVs

Main Site Vent shaft at South Ruislip Victoria Road 7 years <100 (tbc)

Main Site Tunnel portal at West Ruislip Ickenham Road 7 years >800

Main Site Between Breakspear Road South and Harvil Road Breakspear Road 7 years >800 in West Ruislip South/Harvil Road

Satellite Site Diversion of Ickenham Stream to River Pinn and Breakspear Road 1 year >100 footbridge south of Ruislip Golf Course South

Satellite Site Retained embankment south of Ruislip Ickenham Road/ 7 years >100 Golf Course and continuing directly west of Breakspear Road Breakspear Road South South

Satellite Site River Pinn underbridge Breakspear Road 1 year >100 South

Satellite Site Breakspear Road South underbridge Breakspear Road 1 year >100 South

Satellite Site Private access west of Breakspear Road South Breakspear Road 0.5 years >100 South

Satellite Site Cutting north of Marylebone to Aylesbury Line Breakspear Road 1 year >100 between Breakspear Road South and Harvil Road South

Satellite Site Harvil Road realignment Harvil Road 0.5 years >100

Satellite Site Harvil Road bridge over Newyears Green Bourne Harvil Road 0.5 years >100

Satellite Site Harvil Road bridge over Marylebone to Aylesbury Harvil Road 0.5 year >100 Line

Satellite Site Harvil Road bridge over Proposed Scheme Harvil Road 1.5 years >100

Table 13: Typical vehicle trip generation for site compounds in this area

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12.5.4 Levels of traffic generated by construction activities at the proposed vent shaft at South Ruislip throughout the construction period are not expected to exceed 50 HGVs per day in each direction (total inbound and outbound), which is small (less than 10%) in comparison to the wider area traffic flows. However, for the other main construction site compounds in this area, HGVs would be expected to form a relatively high proportion of overall traffic flows and increases of over 30% over forecast baseline levels could be expected including diverted traffic flows. Construction activity related to the main site between Breakspear Road South and Harvil Road is expected to generate more than 800 HGV movements per day in each direction (total inbound and outbound). Further certainty on construction traffic movements will be available as the design progresses. For details of site access road locations, refer to maps CT‑06-014 to CT‑06-018.

12.5.5 Other than at the South Ruislip vent shaft site, the levels of baseline traffic and the access arrangements, together with diversionary effects means that construction traffic is expected to have a significant impact on traffic levels on roads around the worksites. For details of construction traffic routes, refer to maps ‑CT 05-014 to CT‑05-018. The controls imposed by the CoCP will seek to limit impacts around the compounds.

12.5.6 The measures set out in the draft CoCP would include HGV management and control measures. Local proposals relevant to each community forum area for the management of construction traffic, including any required alterations to local roads, proposed cessac routes for site traffic, and for all HGV movements would be set out under local environmental management plans. A project framework travel plan would incorporate route-wide travel planning measures and would include the need for a project-wide travel plan manager, initial travel surveys during construction and a monitoring framework to reduce construction impacts.

12.5.7 It is anticipated that construction vehicles can be wholly accommodated within the worksites and a separate lorry holding area would not be required.

12.5.8 Vehicles would access the proposed vent shaft main site at South Ruislip from Victoria road via an existing industrial estate service road on the southern side of Victoria Road. Vehicles would access the tunnel portal main site at West Ruislip from Ickenham Road and Hill Lane, turning left into the grounds of Ruislip Golf Club. The use of Ruislip Golf Club would entail the loss of around 20 private off-street parking spaces. The main tunnel and rail construction site compound at West Ruislip would be accessed via Breakspear Road South or Harvil Road with main Ruislip Tunnel excavated material removed via Harvil Road. Vehicles unable to pass under the Breakspear Road South Marylebone to Aylesbury Line bridge would access the site via Swakeleys Road (B467) High Road Ickenham (B466), Ickenham Road (B466), the A4180, Ladygate Lane and Breakspear Road South. See also 2.3.17.

12.5.9 For each of these sites, it is expected that the main impacts would be localised, confined mainly to additional construction vehicle trips and turning movements into and out of construction site compounds. However, there would be HGV movements between the A40 and the main site between Breakspear Road South and Harvil Road in West Ruislip. The majority of these movements would be via Harvil Road; however, the site compound would also require a new site access to be constructed on the northern side of Gatemead Farm on the western side of Breakspear Road South. Bridge construction works would also require a temporary closure of Breakspear Road South and an approximately 3.3km diversion of general traffic via Swakeleys Road (B467) High Road Ickenham (B466), Ickenham Road (B466), the A4180, Ladygate Lane and Breakspear Road South. Cyclists would be required to undertake a diversion of approximately 3.2km via Swakeleys Road (B467) High Road Ickenham (B466), Ickenham Road (B466), Church Avenue, The Oaks, the A4180, Ladygate Lane and Breakspear Road South.

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12.5.10 Pedestrians would be required to undertake lengthy diversions of nearly 2km following the closure of Breakspear Road South for bridge construction works. The construction of two bridges over PRoW in the River Pinn/Ruislip Golf Course area would require diversions of around 800m and 2.3km. Whilst there are no footways along the section of Breakspear Road in the vicinity of the railway bridge under the existing situation, it does not preclude the use of the carriageway by pedestrians. In the event of a full closure of Breakspear Road South, pedestrians would be required to undertake a diversion via the River Pinn PRoW.

12.5.11 Works associated with the main site between Breakspear Road South and Harvil Road in West Ruislip would require the construction of a new road and three new permanent bridges on Harvil Road over the existing Marylebone to Aylesbury Line, the Proposed Scheme and a stream to the north. The new road would be to a more direct alignment with limited closures to traffic to allow for connecting into the existing road. It is expected that traffic signals would be utilised to maintain alternate northbound and southbound traffic flow during these works with limited bus and general traffic diversions. However there would be limited periods when full closures of Harvil Road are required and in this case Breakspear Road North and South in conjunction with Ladygate Lane would be the main diversion route.

12.5.12 The application of the measures set out in the draft CoCP would limit disruption to pedestrian and cycle routes by: minimising the need for, and duration of, diversions; providing clearing signage of diversions; ensuring they are suitable for mobility-impaired users; and providing controls at site accesses to ensure safety. However, construction activities would result in disruption to pedestrian and cycle routes through and around the worksites. Mitigation included in the assessments is to limit traffic diversions for any closure of Breakspearoad R South and Harvil Road and may also include maintaining a limited traffic flow (e.g. through one-way or shuttle working or limiting closures to off peak or weekend periods only). Priority would be given to maintaining walk, cycle, bus and servicing and emergency modes during construction.

12.5.13 It is assumed that the majority of construction employees would arrive on public transport or by staff minibus. The sites would have very limited on-site parking. Likely residual significant effects

12.5.14 A number of traffic and transport impacts as a result of the ProposedScheme in the South Ruislip to Ickenham area would have significant effects, due to the numbers of travellers affected and/or the duration of the impact. Even with mitigation in the form of traffic diversions, it is expected that there would be residual effects on all modes to some extent in the form of increased congestion and delays to all road users. Priority would be given to limiting effects on walk, cycle, bus, servicing and emergency modes.

12.5.15 Further effects on London Underground and National Rail operations as a direct result of construction works are to be determined at a later time when the required engineering design and construction strategy data becomes available. These will be reported in the formal ES.

12.5.16 The location of the South Ruislip vent shaft and comparatively low volume of construction traffic generated is not expected to create any significant traffic or transport effects. However, for the main site compounds to the west of this area, the increase in traffic flows would generally represent an increase of more than 30% which is regarded as significant.

12.5.17 The loss of around 20 private off street parking spaces at Ruislip Golf Club during the construction phase would constitute a significant effect.

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12.5.18 The closure of Breakspear Road South and 3.3km traffic diversion would result in an additional journey time of approximately six minutes (assuming a constant 20mph speed), and would constitute a significant effect. Additional information on potential highway diversions can be found in Section 2. Cyclists undertaking the slightly shorter 3.2km diversion would experience an additional journey time of approximately 16 minutes. Again however, it is expected that a low number of cyclists would be affected and the significance would therefore be minor.

12.5.19 Some pedestrian diversions associated with closure of Breakspear Road South and PRoW in the area would require lengthy diversions in excess of 30 minutes. However, as fewer than 200 pedestrians per day would be affected, this would constitute a minor significant effect. Additional information on potential footpath diversions can be found in Section 2.

12.5.20 The severance effect of the closures is expected to be of minor significance as less than 200 pedestrians would be affected in every case.

12.5.21 While a small residual risk of collisions during the construction period would remain as a result of construction vehicle movements into and out of the main and satellite site compounds, the historically low number of accidents combined with forecast traffic increases below 10% is not expected to constitute a significant effect. 12.6 Operation Assessment of impacts and mitigation

12.6.1 During the operational phase, it is expected that the highway and any parking/loading arrangements would be mostly reinstated to their pre-construction condition with no permanent effects. Bus, pedestrian and cycle arrangements would also be expected to return to pre-construction conditions. The exceptions would be at Breakspear Road South where new permanent underbridge structures would be provided over Breakspear Road South and River Pinn and at Harvil Road where a new road alignment and three new permanent underbridges would create a more direct road alignment. Additionally at Breakspear Road South, the PRoW immediately north and parallel with the trace leading east towards the River Pinn would be relocated following construction of the new underbridge. Likely residual significant effects

12.6.2 Servicing requirements for the Ruislip Tunnel Vent Shaft are expected to have no significant impacts on the local highway network with occasional vehicles accessing the site from Victoria Road via the industrial estate service road.

12.6.3 The new more direct road alignment at Harvil Road is expected to have no significant effects on traffic or transport.

12.6.4 The realigned PRoW to the north of the new Breakspear Road under bridge is expected to have no significant effects on pedestrian delay or severance. Further mitigation

12.6.5 The assessments undertaken at this stage have indicated that for this area there would be no significant transport related effects during operation of the ProposedScheme that require mitigation. This is because: • There would be no stations or depots that generate substantial additional traffic; and • All roads that would cross the route would either be reinstated to their pre-construction condition or a new, more direct alignment provided.

88 CFA Report – South Ruislip to Ickenham/No 6 I Water resources and flood risk assessment 13 Water resources and flood risk assessment 13.1 Introduction 13.1.1 This section provides a summary of the likely impacts and significant effects on water resources and flood risk as a result of the construction and operation of the ProposedScheme. The assessment considers effects on surface water resources, groundwater resources and flooding risk. 13.2 Policy framework 13.2.1 Policy 5.12 of the London Plan states that development proposals must comply with flood risk assessment and management requirements set out in the National Planning Policy Framework. A number of other relevant policies are included: • Policy 5.3 requires that sustainable design standards are integral to construction and operation; • Policy 5.13 states that development should utilise sustainable drainage systems (SuDS), aiming to achieve greenfield run-off rates unless there are practical reasons why they should not be used; • Policy 5.14 requires that adequate wastewater infrastructure capacity is available in tandem with development and seeks to protect and improve water quality having regard to the River Basin Management Plan61; and • Policy 5.15 states that development should minimise the use of mains water, incorporating water saving measures.

13.2.2 The Hillingdon Local Plan: Part 1 2012 Policy EM 6 seeks to direct development away from flood zones 2 and 3 and requires the use of SuDS and other water efficiency methods. Policy EM 8 seeks to safeguard surface and ground water quality. Saved UDP Policy OE7 of Hillingdon Local Plan: Part 2 requires that, in areas liable to flooding, flood protection measures are included for in development, Saved Policy OE 8 aims to prevent development that would result in an increased flood risk from surface water run-off, and Saved Policy OE9 makes similar provision in relation to sewerage flooding.

13.2.3 In addition, local and regional guidance is relevant to this assessment including: • The Mayor’s Water Strategy62; • The London Regional Flood Risk Assessment (RFRA) 200963; and • The LBH Strategic Flood Risk Assessment (SFRA) 200864. 13.3 Assessment scope and key assumptions 13.3.1 The assessment scope and key assumptions for the water resources and flood risk assessment are set out in Volume 1.

13.3.2 The assessment of surface water resources and flood risk focuses on the River Pinn, Ickenham Stream and the Newyears Green Bourne and their associated catchment areas and floodplains.

61 Environment Agency (2009), River Basin Management Plan, Thames River Basin District. 62 Greater London Authority (2011), Securing London’s Water Future. 63 Greater London Authority (2009), London Regional Flood Risk Assessment. 64 London Borough of Hillingdon (2008), Strategic Flood Risk Assessment.

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13.3.3 The groundwater resources assessment focuses on underground water-bearing layers (aquifers) that are present within bedrock and overlying deposits. Effects on groundwater dependent terrestrial ecosystems (GWDTEs) and groundwater users (both licensed abstractions and private users) are also considered. 13.4 Environmental baseline 13.4.1 The Proposed Scheme is described in Section 2 of this report. The study area is largely urban (see map CT‑04-05) and Yeading Brook (east and west arms), the River Pinn, and the Ickenham Stream (originally constructed as a feeder for the Grand Union Canal and referred to elsewhere as the ‘canal feeder’), Newyears Green Bourne; and four un-named surface drains and four ponds are surface water features located within the study area of the Proposed Scheme.

13.4.2 The EA reports the Water Framework Directive (WFD) classifications of the Yeading Brook and the River Pinn to be “moderate” relative to ecological quality65. Both watercourses are noted to be heavily modified and do not require assessment for chemical quality. Predictions for 2015 are same as current (i.e. “moderate”). The EA holds no data regarding the WFD status of Ickenham Stream (canal feeder) or Newyears Green Bourne.

13.4.3 The EA records indicate that there have been several significant pollution incidents, including four in the vicinity of the Yeading Brook (east arm) since 1998. Two incidents were directly on the Yeading Brook (east arm); one approximately 200m north of the route and one 80m south of the route. Two other incidents were recorded in the catchment feeding the Yeading Brook (east arm), approximately 200 and 450m north of the route, respectively. In addition, three incidents were recorded in the catchment feeding the River Pinn; one approximately 150m north of the route and two approximately 450m north of the route. There are no consented surface water abstractions or discharges in the area.

13.4.4 Superficial deposits are present at the western end of the study area and comprise a narrow ribbon of alluvium associated with the River Pinn. An outcrop of the Lambeth Group may also be present and in this area is described as mottled sandy clay and clayey sand. The alluvium and Lambeth Group are both designated as Secondary A Aquifers by the EA. The underlying bedrock geology is the London Clay Formation which has been designated as unproductive strata. Beneath this is the Lambeth Group which is underlain by the Chalk Group (which is classified as a Principal Bedrock Aquifer).

13.4.5 The direction of shallow groundwater flow within the alluvium associated with the River Pinn is unknown but is likely to follow the topography, and to have a hydraulic connection with the River Pinn. The London Clay is present above the Chalk aquifer and has a low permeability. Groundwater elevation data for the Chalk indicates the Chalk groundwater is under pressure or ‘confined’ beneath the London Clay. Groundwater flow within the Chalk is generally towards the east and south-east.

13.4.6 The following licensed groundwater abstractions and wells have been identified in the area: • Two licensed groundwater abstractions for public water supply which have associated SPZs within 1km of the route. The route would pass through one SPZ1 (see map CT‑04-05). These abstract water from the Chalk aquifer; • Three other licensed groundwater abstractions within 2km of the route. These abstract water from the Chalk aquifer; and

65 Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Strasbourg, European Parliament and European Council.

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• Two additional water wells within 500m of the route for unknown use. These are expected to abstract water from the Chalk aquifer. Further information will be included in the formal ES if available.

13.4.7 The EA provided hydraulic models of the River Crane (including the Yeading Brook) and River Pinn which have been used to obtain design flood water levels for assessment. Information from the LBH Strategic Flood Risk Assessment (SFRA), Preliminary Flood Risk Assessment (PFRA) and Surface Water Management Plan (SWMP) has been used as the basis of the baseline for flood risk within the study area66,67,68.

13.4.8 The key features with respect to potential flood risk (see map CT‑04-05) and the Proposed Scheme are as follows: • The River Pinn has a catchment size of 29km2. The route would cross approximately 180m of Flood Zone 3 and 200m of Flood Zone 2 at this location. Severe flooding occurred along the River Pinn in 1977, when 718 residential and commercial properties were affected in the Hillingdon area. Further flooding events occurred in 1988 when 160 properties experienced flooding; • There is an additional risk of flooding at the River Pinn crossing point in the vente of failure of Ruislip Lido; • The Newyears Green Bourne has a catchment size of approximately 5km2 and the diversion of Harvil Road would cross approximately 62m of Flood Zone 2 and 52m of Flood Zone 3; • There are locations that are shown in the LBH PRFA and SWMP to be at risk of surface water flooding within the study area. In particular, close to the existing railway junction in South Ruislip, in Ruislip Gardens, and surrounding West Ruislip Underground Station. These areas are all identified in the SWMP as being ‘critical drainage areas’. There is also an area at risk of surface water flooding to the north of Ickenham Close and Copthall Farm; • A total of 164 properties have flooded from overloaded sewers (surface water, foul and combined sewers) in the past ten years; and • The route crosses areas classified by the British Geological Survey (BGS) as having ‘very high’ susceptibility to groundwater flooding at the River Pinn and ‘high’ susceptibility to groundwater flooding in local superficial deposits at the London Underground depot at Ruislip Gardens. 13.5 Construction Assessment of impacts and mitigation

13.5.1 The draft CoCP sets out the measures and standards of work that will be applied to the construction of the Proposed Scheme. It would provide effective management and control of the impacts during the construction period including those required for utility diversions and strengthening, compensation grouting, tunnelling and vent shaft and tunnel portal construction.

13.5.2 The draft CoCP includes the following provisions: • Implementing, in consultation with the EA and Lead Local Flood Authorities (LLFAs), a surface water and/or groundwater monitoring plan as required, particularly in relation to works which may affect groundwater sensitive areas;

66 London Borough of Hillingdon (2008), Strategic Flood Risk Assessment. 67 Capita Symonds (2011), London Borough of Hillingdon Preliminary Flood Risk Assessment. 68 Capita Symonds (2013), London Borough of Hillingdon Surface Water Management Plan.

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• Undertaking site-specific risk assessments associated with excavation work and impacts on surface water; groundwater; abstractions; aquifers and private water supplies; • Preparing further site-specific flood risk management plans for those areas at risk of flooding; • Avoiding the use of contaminating materials through appropriate design, construction and equipment specification and wherever possible, using biodegradable substances; • Following the measures outlined for the provision of suitable site drainage, for the storage and control of oils and chemicals and to mitigate against accidental spillages; and • Undertaking, as required, further pre-construction monitoring to establish baseline water quality conditions for watercourses; groundwater and during construction works. This would enable the effectiveness of those mitigation measures introduced to limit pollution risk to be monitored and any pollution incidents to be identified.

13.5.3 The following examples illustrate how the draft CoCP would reduce potential effects to levels that would not be significant: • Measures defined in the CoCP, including detailed method statements, would ensure that there would be no effect on surface water quality or flows associated with general construction practice; • Following the application of drainage management measures in the CoCP, the construction of embankments in the vicinity of the River Pinn is not anticipated to impact upon the flow or quality of shallow ground water in potential connection with the watercourse. No net change to infiltration and thus to shallow groundwater contributions to the river are anticipated, and the type of deposits present (alluvium) would reduce the potential for compaction. No significant effects are anticipated; and • Where small private abstractions are remote from areas of excavation, impacts are predicted to be negligible and therefore not significant due to application of theCoCP.

13.5.4 The effects of construction identified below are those that fall outside the scope of the measures in the draft CoCP and/or may require special consideration in the design process.

13.5.5 The Ickenham Stream (canal feeder) would require a permanent diversion in order to facilitate the tunnel portal construction works at West Ruislip. The route of this diversion would be along the northern edge of the route and across the Ruislip Golf Course for 680m to the River Pinn. This diversion has the potential to affect watercourse quality and flow. The new Ickenham Stream (canal feeder) channel would be constructed in advance in line with EA guidance and advice in terms of flow capacity, and thus the impact on flow would be minor. There would be short term and temporary impacts on water quality which would also be minor. Therefore, overall, the impacts of construction on the Ickenham Stream would not be significant.

13.5.6 A separate minor diversion to the Newyears Green Bourne may also be required. This would have slight, short term impacts, with no resulting significant effects.Confirmation of diversion works for both the Ickenham Stream and Newyears Green Bourne will be reported in the formal ES.

13.5.7 The tunnelling methodology would be selected to avoid significant groundwater ingress into the tunnels and there is no anticipated requirement to remove significant quantities of water (dewatering). Dewatering during construction of some cross passages and works to connect shafts to the main tunnels would be minor in nature and of short term duration (assumed to be up to three months) and therefore not significant.

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13.5.8 The vent shaft at South Ruislip would extend close to the base of the Lambeth Group and dewatering would be needed to construct the base slab within the shaft. The nearest groundwater abstraction is over 1.5km away and so the impact on groundwater flows and levels supplying the abstraction would be negligible, and therefore not significant.

13.5.9 Although it appears unlikely to be necessary, if depressurisation of the underlying Chalk aquifer is required to stabilise the portal in cutting during construction, this would be undertaken by short term use of temporary, shallow dewatering wells installed within the portal walls. Abstraction would only occur to maintain groundwater levels in the Chalk to just below the working levels, so there would be negligible impact on flows and levels in the Chalk aquifer and no impact on water quality in the Chalk, and, therefore, no significant effect.

13.5.10 Tunnelling and piling would have the potential to impact on groundwater quality due to the migration of fluids or suspended bedrock particles potentially giving rise to increased turbidity. Notwithstanding the CoCP, there could be potential for moderate but temporary impacts on groundwater quality. If rapid pathways through the Lambeth Group and underlying Chalk to high value receptors such as public water supply or private boreholes exist this could result in moderate impact to high value receptors. This would be a significant effect.

13.5.11 The discharge from any dewatering activity would be directed either to a Thames Water sewer or to the Yeading Brook. This discharge would operate for a period of months and would be at rates agreed in consultation with the EA or Thames Water. There would be no significant effect on surface water flooding as a result.

13.5.12 A number of construction areas would be located within areas at risk of flooding. During the construction stage there is a risk of flooding in terms of inundating excavations, damage to plant and materials used on-site and the safety of the construction workforce. Any potential for increase in off-site flood risks would be managed by measures defined in the CoCP and reported in the flood risk assessment.

13.5.13 The route crosses an area with a ‘high’ susceptibility of groundwater flooding at the London Underground depot at Ruislip Gardens and at this location the route is in tunnel. The route also crosses an area with a ‘very high’ susceptibility of groundwater flooding associated with the alluvial deposits of the River Pinn. At this location, the route is on an embankment. The impact of the construction works at these locations on the risk of flooding from groundwater in these areas would not result in significant effects on local receptors.

13.5.14 To avoid having an impact on the risk of flooding from the River Pinn, excavated material storage and site offices would be located outside of the flood zones.Appropriate compensatory flood storage for the operational scheme would be provided prior to construction of the embankment between Breakspear Road South and Harvil Road, and this would mitigate loss of floodplain storage resulting from any minor temporary construction in the floodplain (see 13.6.8). Therefore, there would be no significant effect on flooding risk with respect to local receptors.

13.5.15 With respect to the Ickenham Stream (canal feeder) diversion, the construction of the new channel prior to the diversion of waters would reduce the risk of flooding during construction. Likely residual significant effects

13.5.16 There could be significant impacts to groundwater quality as a result of tunnelling and piling. Where the proposed route passes through an SPZ1 for a public water supply or close to private abstractions, further mitigation would be required.

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Further mitigation

13.5.17 Mitigation for any effects on groundwater levels and quality at private abstractions and public water supply would be resolved with stakeholders, including Affinity Water. A hierarchy of mitigation would be considered which includes groundwater monitoring to establish the level of impact and further mitigation, as appropriate, particularly to avoid unplanned withdrawal of public water supply and impacts on customers. Consultation and mitigation applicable to other abstractors will be reported in the formal ES. 13.6 Operation Assessment of impacts and mitigation

13.6.1 The Proposed Scheme has been designed to control impacts on the water environment through the following: • Drainage has been designed to reduce the rate and volume of run-off from the railway and prevent an increase in flood risk; • Sustainable drainage systems, where appropriate, have been included to encourage water to soak back into the ground; and where drainage or cuttings intercept groundwater flow; and • Sustainable drainage systems would also provide opportunities to reduce the effect on water quality by reducing potential contaminants through filtration, vegetation adsorption or settlement.

13.6.2 Best practice pollution control guidance would be adopted for maintenance of the Proposed Scheme.

13.6.3 All drainage, including fire fighting discharges, would discharge to Thamesa Water sewer under an appropriate consent covering water quality and run-off rates. Lined tunnels are effectively impermeable and the background drainage rate would be small. Vent shafts and associated access roads and hardstandings would be designed to reduce peak run-off rates through use of sustainable drainage system techniques. The effects on flows would therefore not be significant.

13.6.4 The permanent diversion of the Ickenham Stream (canal feeder) during the construction phase has the potential to result in slight impacts on water quality and flow that extend through the first stages of operation as the diverted section stabilises. Effects would be expected to return to neutral without further mitigation being required, however monitoring, as required, would extend into operation, with appropriate remedial action being taken if needed.

13.6.5 Although the tunnel would pass through the Lambeth Group Secondary A Aquifer, the cross- sectional area of the tunnel is relatively small in comparison with the assumed effective thickness of the Lambeth Group and Chalk aquifers. This is a minor impact restricted to the immediate vicinity of the tunnel and would not affect overall flow rates.The effect on flows is therefore not significant. No additional operational impacts upon groundwater are anticipated.

13.6.6 At the bridge over the River Pinn, the route crosses the river approximately 30m north of an existing viaduct. The Pinn floodplain is constrained beneath the existing viaduct which can cause water to back up on the northern side of the existing embankment during flood vents.e The Proposed Scheme includes a bridge which would be designed to span the River Pinn and would be wider than the existing downstream crossing, therefore no significant flood flow obstruction is expected. The embankments for the underbridge would be located in the

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floodplain and would therefore displace flood waters, increasing flood watervels le upstream. The land use upstream of the crossing is recreational (Ruislip Golf Club) and agricultural. The loss in floodplain storage due to the new River Pinn crossing embankment and details regarding upstream flood water levels will be provided in the formal ES and FRA.

13.6.7 Harvil Road would be permanently realigned as part of the Proposed Scheme, and raised above the 1 in 1,000 year annual probability (0.1%) flood level on an embankment. A clear span overbridge is proposed to allow the Newyears Green Bourne to flow beneath the road embankment. Enlarging the existing watercourse crossing, which currently poses an obstruction to flood flows, would have an impact on the risk of flooding to local receptors from the Newyears Green Bourne. Flood water levels upstream of the embankment would be reduced; however, downstream flood water levels have the potential to increase (the precise effect is being modelled and will be reported in the formal ES). Although there would be a beneficial effect upstream due to the reduction in flood risk, the potential impact on downstream receptors results in there being an overall moderate and therefore significant adverse effect.

13.6.8 The design of the Harvil Road overbridge across the Newyears Green Bourne would incorporate measures to prevent increases in the risk of flooding downstream. Such measures could potentially include construction of a flood storage area, channel and/or floodplain re- profiling, or replication of the capacity of the existing crossing within the new design.The formal ES will include details of appropriate mitigation. Likely residual significant effects

13.6.9 The potential residual effects on the surface water environment include those from the permanent diversion of the watercourses. The residual effect of these changes is anticipated to return to negligible, without the need for further mitigation. In order to ensure that conditions within the water environment are not compromised, monitoring would extend for a limited period over the course of the establishment of the new features, with appropriate remedial action being taken if required. Further mitigation

13.6.10 Appropriate measures would be included in the design to ensure that flood risk is acceptable during operation of the Proposed Scheme. The precise nature of these measures will be defined in the formal ES once modelling of the flood risk has been completed.

13.6.11 An opportunity for a positive effect has been identified through the diversion of the Ickenham Stream (canal feeder). The outfall from the diverted Ickenham Stream (canal feeder) to the River Pinn would be restricted in order to reduce the risk of flooding in the Pinn catchment from any additional flow. The channel of the diverted watercourse would be designed to contain a 1 in 100 annual probability (1%) flood event plus an allowance for predicted increase in flow as a result of climate change without overtopping, thereby reducing the risk of flooding on the golf course.

95 CFA Report – South Ruislip to Ickenham/No 6 I References 14 References Arup/URS (2013), Phase One: Draft Code of Construction Practice. London, HS2 Ltd.

British Geological Survey (2012), Green infrastructure and open environments: London’s Foundations: Protecting the Geodiversity of the Capital Supplementary Planning Guidance.

Capita Symonds (2011), London Borough of Hillingdon Preliminary Flood Risk Assessment.

Capita Symonds (2013), London Borough of Hillingdon Surface Water Management Plan.

Cranfield University (2001),The National Soil Map of England and Wales 1:250,000 scale, National Soil Resources Institute, Cranfield University, UK.

Countryside Commission (1998), Countryside character, South East and London national character areas, Countryside Agency, http://www.naturalengland.org.uk/publications/nca/southeast.aspx, Accessed: 24 May 2012.

Campaign to Protect Rural England, CPRE Tranquillity Map: England, www.cpre.org.uk/resources/ countryside/tranquil-places/item/1839, Accessed: 16 April 2013.

Department for Communities and Local Government (2012), National Planning Policy Framework.

Department for Food, Environment and Rural Affairs (2005), Likelihood of Best and Most Versatile Agricultural Land.

Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Strasbourg, European Parliament and European Council.

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