Re p or t

Eastern Villages Southern Connector Road Feasibility Study

Prepared for Swindon Borough Council

Date March 2014

Burderop Park Swindon SN4 0QD

COPYRIGHT MARCH 2014 BY CH2M HILL

Contents

Section Page Acronyms and Abbreviations ...... ix 1 Introduction ...... 1-1 1.1 Project brief ...... 1-1 1.1.1 Task list ...... 1-1 1.1.2 Deliverables ...... 1-1 1.2 Methodology ...... 1-1 1.3 Existing studies and information ...... 1-2 2 Existing conditions ...... 2-3 2.1 Location and Character...... 2-3 2.1.1 Eastern Villages development location ...... 2-3 2.1.2 Existing landscape ...... 2-3 2.1.3 Speed limits ...... 2-3 2.1.4 Lighting ...... 2-3 2.1.5 Parishes ...... 2-3 2.2 Land ownership and third parties ...... 2-4 2.3 Highways and structures ...... 2-4 2.3.1 Highways ...... 2-4 2.3.2 Structures ...... 2-4 2.4 Surface Water Management ...... 2-4 2.5 Transport and access ...... 2-5 2.5.1 Existing Road Network ...... 2-5 2.5.2 Other Accesses ...... 2-6 2.5.3 Public Transport ...... 2-6 2.6 Geotechnical conditions ...... 2-6 2.7 Environmental conditions ...... 2-7 2.7.1 Phase 1 Survey ...... 2-7 2.8 Public utilities ...... 2-7 2.9 Non Motorised Users ...... 2-7 2.9.1 Existing Footway / Cycleway Provision ...... 2-7 2.9.2 Footpaths and Bridleways ...... 2-7 3 Scheme Development ...... 3-1 3.1 Introduction ...... 3-1 3.2 Need for the Scheme ...... 3-1 3.2.1 Eastern Villages & Masterplan...... 3-1 3.3 Summary of Previous Work ...... 3-1 3.4 Optioneering ...... 3-2 3.4.1 Eastern Villages Highway Concept ...... 3-3 3.4.2 Constraints ...... 3-4 3.4.3 Design Speed 30mph/60kph ...... 3-5 3.4.4 Design Speed 40mph/70kph ...... 3-5 3.4.5 Design Speed 50mph/85kph ...... 3-5 3.4.6 Design Speed 60mph/100kph ...... 3-6 3.4.7 Pack Hill widening ...... 3-8

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Section Page 4 Highways ...... 4-1 4.1 Proposed Eastern Villages Southern Connector Road ...... 4-1 4.1.1 Introduction ...... 4-1 4.2 Speed limit proposals ...... 4-1 4.3 Highway alignment ...... 4-2 4.3.1 Horizontal alignment design parameters ...... 4-2 4.3.2 Horizontal alignment constraints ...... 4-2 4.3.3 Vertical alignment design parameters ...... 4-2 4.3.4 Vertical alignment constraints ...... 4-2 4.4 The Marsh junction ...... 4-3 4.4.1 Introduction ...... 4-3 4.4.2 Junction format ...... 4-3 4.4.3 The Marsh ...... 4-3 4.5 Anti-glare screening ...... 4-3 4.6 Wanborough Road ...... 4-3 4.6.1 Introduction ...... 4-3 4.6.2 Constraints ...... 4-3 4.6.3 Wanborough Road crossing point options ...... 4-4 4.6.4 Preferred crossing point options ...... 4-6 4.7 Commonhead roundabout...... 4-7 4.8 Street lighting ...... 4-8 4.8.1 Existing street lighting ...... 4-8 4.8.2 Lighting requirements ...... 4-8 4.9 Traffic Flow Assessment...... 4-9 4.9.1 Traffic Flows ...... 4-9 4.10 Carriageway pavement and foundation design ...... 4-9 4.10.1 Typical Pavement Construction ...... 4-9 4.11 Carriageway width and cross-section ...... 4-10 4.11.1 Existing Road Widths ...... 4-10 4.11.2 Proposed road width and cross section ...... 4-10 4.12 Road Restraint Systems (RRS) ...... 4-11 4.12.1 Requirements for Provision of RRS ...... 4-11 4.12.2 Highways hazards requiring RRS protection ...... 4-12 4.12.3 Vehicle parapets requiring RRS protection ...... 4-12 4.12.4 Containment levels at vehicle parapets ...... 4-12 4.12.5 Minimum Lengths of RRS ...... 4-13 4.12.6 Locations requiring safety barrier ...... 4-13 4.13 Road Safety Audit ...... 4-13 5 Structures ...... 5-1 5.1 Existing structures affected ...... 5-1 5.2 Proposed structures ...... 5-1 5.2.1 Wilts & Berks Canal structures (Ref 1 & 2) ...... 5-2 5.2.2 Liden Brook river structure (Ref 4) ...... 5-2 5.2.3 Wanborough Road overbridge (Ref 6) – Option A3 ...... 5-3 5.2.4 Wanborough Road underpass (Ref 7) – Option A4 ...... 5-3 5.2.5 Drainage Channel Crossing (Ref 3 & 5)...... 5-4 6 Flood Risk Assessment and Drainage Strategy ...... 6-1 6.1 Flood risk assessment ...... 6-1

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Section Page 6.1.1 Introduction ...... 6-1 6.1.2 Eastern Village Southern Connector Road ...... 6-1 6.1.3 Overview of flood risk to the proposed route ...... 6-1 6.2 Methodology ...... 6-3 6.2.1 Policy review ...... 6-3 6.2.2 Assessment of flood risk (all sources) ...... 6-5 6.2.3 Flood Risk Summary ...... 6-10 6.3 Compensatory Flood Storage Areas ...... 6-10 6.4 Conceptual drainage strategy ...... 6-11 6.4.1 Introduction ...... 6-11 6.4.2 Design Assumptions ...... 6-11 6.4.3 Existing surface water runoff rates and volumes ...... 6-12 6.4.4 Proposed drainage strategy ...... 6-13 6.4.5 Sustainable urban drainage options ...... 6-18 6.4.6 Design Exceedance ...... 6-20 6.4.7 SUDS management train ...... 6-20 7 Geotechnical assessment ...... 7-1 7.1 Introduction ...... 7-1 7.2 Purpose of the Desk Study ...... 7-2 7.3 Sources of information ...... 7-2 7.4 Site location and description ...... 7-2 7.4.1 Plan Alignment ...... 7-4 7.4.2 Ground Elevation and Vertical Alignment ...... 7-4 7.5 Site Background ...... 7-4 7.5.1 Site History ...... 7-4 7.5.2 Unexploded Ordnance ...... 7-5 7.5.3 Walkover Survey ...... 7-5 7.5.4 Utilities ...... 7-5 7.6 Geology and Ground Investigation Records ...... 7-6 7.6.1 Local Geology ...... 7-6 7.6.2 Ground Investigation Records ...... 7-6 7.6.3 Coal Mining Activities ...... 7-9 7.6.4 Hydrology and Hydrogeology ...... 7-9 7.7 Geotechnical Issues ...... 7-10 7.7.1 Scheme Overview ...... 7-10 7.7.2 Assessment of Geotechnical Issues ...... 7-10 7.8 Environmental and Contaminated Land Issues...... 7-11 7.9 Recommendations for Ground Investigation...... 7-12 7.10 References ...... 7-12 8 Environmental appraisal...... 8-1 8.1 Existing Environment ...... 8-1 8.1.1 Local Community ...... 8-1 8.1.2 Flora and Fauna ...... 8-2 8.1.3 Landscape and Visual Amenity ...... 8-2 8.1.4 Water ...... 8-3 8.1.5 Land Use ...... 8-4 8.1.6 The Historic Environment ...... 8-4 8.1.7 Transport and Access ...... 8-5

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Section Page 8.1.8 Geology/Contaminated Land ...... 8-5 8.2 Appraisal of Environmental Issues, Constraints and Opportunities ...... 8-5 8.3 Further Work and Environmental Consenting ...... 8-8 8.4 References...... 8-9 9 Statutory undertakers & stakeholders ...... 9-1 9.1 Public utilities ...... 9-1 9.1.1 Public utilities present affected ...... 9-1 9.1.2 Anticipated public utilities diversionary and protection works ...... 9-3 9.1.3 Scottish & Southern Energy ...... 9-5 9.1.4 Thames Water...... 9-5 9.1.5 Wales & West Utilities ...... 9-5 9.1.6 New public utilities works ...... 9-5 9.2 Stakeholders ...... 9-5 9.2.1 Fire Service and Fire Safety...... 9-5 9.2.2 Ambulance Service and Health Facilities ...... 9-6 9.2.3 Wilts & Berks Canal Trust ...... 9-6 9.2.4 Environment Agency ...... 9-6 10 Public Transport ...... 10-1 10.1 Eastern Villages public transport proposals ...... 10-1 10.2 Existing public transport ...... 10-1 10.2.1 Existing bus routes ...... 10-1 10.2.2 Existing bus stop locations...... 10-1 10.2.3 Public transport proposals...... 10-1 11 Non motorised users...... 11-1 11.1 Existing NMU provision ...... 11-1 11.2 EVSCR footways, cycle routes and bridleways ...... 11-1 11.3 Footway / Cycletracks ...... 11-1 11.3.1 Lighting of NMU routes ...... 11-1 11.3.2 Signing of NMU routes ...... 11-2 11.4 Footpaths ...... 11-2 11.4.1 Crossing point facilities...... 11-2 11.4.2 Footpath proposals ...... 11-3 11.4.3 Footpath 22 diversion ...... 11-3 11.5 Uncontrolled Pedestrian and Cycle Crossings ...... 11-3 11.5.1 Selection of crossing point ...... 11-3 11.6 Equestrians ...... 11-4 11.6.1 Current equestrian requirements ...... 11-4 11.6.2 Equestrian provision ...... 11-4 11.7 Non-Motorised User Audit ...... 11-5 12 Land and accesses ...... 12-6 12.1 Land ...... 12-6 12.1.1 Land and property affected ...... 12-6 12.1.2 Buildings affected...... 12-6 12.2 Accesses ...... 12-6 12.2.1 Residential / Business Accesses ...... 12-6 12.2.2 Wilts & Berks Canal Accesses ...... 12-7

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Section Page 12.2.3 Farm Accesses ...... 12-7 12.2.4 Access Proposals ...... 12-7 13 Delivery Considerations ...... 13-1 13.1 Introduction ...... 13-1 13.2 Public acceptability ...... 13-1 13.3 Construction ...... 13-1 13.3.1 Construction period ...... 13-1 13.3.2 Site access points ...... 13-1 13.3.3 Pack Hill realignment/southern access to Wanborough (Ch 150 – 600) ...... 13-2 13.3.4 The Marsh to Wanborough Road (Ch 640 – 2250) ...... 13-2 13.3.5 The Marsh (Ch 150 - 620) ...... 13-2 13.3.6 Wanborough Road – Options A1 & A2 (at grade junctions) ...... 13-2 13.3.7 Wanborough Road – Option A3 (overbridge) ...... 13-3 13.3.8 Wanborough Road – Option A4 (underpass) ...... 13-3 13.3.9 Liden Brook Structure ...... 13-4 13.3.10 Pack Hill widening ...... 13-4 13.3.11 Public transport ...... 13-4 13.3.12 Flood risk ...... 13-4 13.3.13 Private accesses ...... 13-4 13.3.14 Field accesses & farming ...... 13-5 13.3.15 NMUs ...... 13-5 13.3.16 Environmental considerations ...... 13-5 13.4 Risk Register ...... 13-5 13.4.1 Key Business Case Risks...... 13-5 13.4.2 Key Risks ...... 13-5 13.4.3 Other Risks ...... 13-6 13.5 Cost Estimates ...... 13-6 14 Preferred Route and Options ...... 14-1 14.1 Eastern Villages Southern Connector Road summary ...... 14-1 14.2 Preferred Eastern Villages Southern Connector Road Alignment Option ...... 14-1 14.3 Preferred Wanborough Road Crossing Option ...... 14-2 14.4 Summary of EVSCR Options ...... 14-3

Appendixes A - Site photographs B – Geotechnical Assessment Report C – Environmental Appraisal Report D - Drawings

Tables 1-1 Existing studies and information referenced 3-1 Summary of Previous Related Work 3-2 Alignment constraints 3-3 Summary of Highway Options Considered 4-1 Layout Option Summary 4-2 Typical Pavement Construction Thicknesses 4-3 Minimum Full Height Safety Barrier Length of Need

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Section Page 5-1 Proposed structures summary 6-1 Environment Agency Flood Zones 6-2 Greenfield site runoff for all catchments 7-1 British Geological Survey Borehole Records 8-1 Potential key environmental issues, constraints and opportunities relating to road options under consideration 8-2 Further investigations/consultation likely to be required (independent of any requirement for formal EIA) 9-1 Public utilities within the search area – details received 9-2 Public utilities within the search area – details not received 9-3 Public utilities not affected 9-4 Public utilities – anticipated works 9-5 Public utilities – Pack Hill widening anticipated works 11-1 Summary of Footpath Proposals 11-2 Criteria for Suitability of Informal At-Grade Rights of Way Crossings 13-1 Eastern Villages Southern Connector Road estimated construction costs – With equestrian route widening 13-2 Eastern Villages Southern Connector Road estimated construction costs – No equestrian route widening 13-3 Eastern Villages Southern Connector Road estimated construction costs – Additional cost for equestrian route widening 14-1 Layout Option Summary 14-2 Eastern Villages Southern Connector Road Option Summary

Figures 3-1 Eastern Villages Southern Connector Road Location 6-1 Environment Agency Flood zones (risk of flooding from River and Sea) 6-2 SFRA database for localised flooding in vicinity of proposed road alignment 6-3 Environment Agency Flood Maps (risk of flooding from reservoir) 6-4 Environment Agency Source Protection Zone (SPZ) 6-5 Environment Agency Aquifer Map 6-6 Environment Agency (risk of flooding from surface water) 7-1 Location plan 7-2 Proposed alignment 7-3 BGS Borehole Records in the area of interest

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Acronyms and Abbreviations

DfT Department for Transport EVSCR Eastern Villages Southern Connector Road EVDSPD Eastern Villages Draft Supplementary Planning Document EA Environment Agency LFRM Local Flood Risk Management NPPF National Planning Policy Framework PFRA Preliminary Flood Risk Assessment SWMP Surface Water Management Plan SFRA Strategic Flood Risk Assessment

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SECTION 1 1 Introduction

1.1 Project brief Swindon Borough Council commissioned CH2M Hill in December 2013 to undertake a feasibility study for the proposed Eastern Villages Southern Connector Road (EVSCR), east of Swindon. The Eastern Villages is a proposed large mixed use development east of the A419 which, if permitted, may be developed in phases over a period of about 15 years. To enable this development, a new connector road ( also referred to as Commonhead Link) between the southern limit of the development and the A419 Commonhead Roundabout at Pack Hill would be required to give access for the construction and occupation of some phases of the development.

1.1.1 Task list The tasks for the project are as follows:

a. Review the route options and junctions in terms of geometry, traffic, and drainage. b. Carry out new NRSWA Stage C2 enquiries to statutory undertakers as required. c. Provide an Environmental Appraisal. d. Provide a desktop geotechnical assessment e. Identify structures required f. Feasibility report for Swindon Borough Council g. Cost estimate for high level options considered, incorporating optimism bias. h. Attendance at project/progress meetings.

1.1.2 Deliverables a. Draft report for review and comment. b. Final report. c. Risk register. d. Cost estimate

1.2 Methodology

The proposed Eastern Villages Southern Connector Road will be assessed for feasibility in accordance with national standards set out in the Highways Agency’s Design Manual for Roads and Bridges and Manual for Streets TD37 Scheme Assessment Reporting – Stage 2. At Stage 2 the remit is to identify the factors to be taken into account in choosing alternative routes or improvement schemes and to identify the environmental, engineering, economic and traffic advantages, disadvantages and constraints associated with those routes or schemes. This report sets out the initial work that has been undertaken with regards to the EVSCR in line with the Stage 2 requirements. This will need to include: Optioneering and scheme development of alternative alignments (plans and cost) Environmental assessment including consideration of the flood risk areas

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Comparison of schemes Indicative costs Consideration of stakeholder views and identification of constraints

1.3 Existing studies and information The following existing studies and information have been referenced during preparation of this study

TABLE 1-1 Existing studies and information referenced

Information Title Published By Date

Report Swindon Eastern Villages Transport Study JMP Consultants Ltd April 2011

Report Swindon Eastern Villages Transport Study – Update Report JMP Consultants Ltd December 2012

Report Swindon Borough Council Local Development Framework Swindon Borough Council July 2013 Eastern Villages Draft Supplementary Planning Document

Report Swindon Borough Local Development Framework Swindon Borough Council March 2011 Swindon Borough Core Strategy and Development Management Policies 2026 Swindon: Planning for our future Revised Proposed Submission Document

Plan Swindon Borough Draft Local Plan 2026 Pre-Submission Swindon Borough Council June 2013 Proposals Map

1-2 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 2 2 EXISTING CONDITIONS 2 Existing conditions

2.1 Location and Character 2.1.1 Eastern Villages development location The Eastern Villages development is located to the east of the A419 dual carriageway, approximately 4.5 km east of Swindon town centre. The development will be located between the villages of South Marston and Wanborough with the approximate extent on the Swindon Borough Local Plan 2026 shown on Drg Nos TH/SBCC/230/HIG/104 - 107. The Swindon Borough Local Plan has identified it as a mixed use urban extension of about 8,000 new homes with associated retail, employment, education and leisure uses. 2.1.2 Existing landscape The site of the Eastern Villages development currently comprises an area of relatively low lying open fields and flood plains. The surrounding countryside is of a high quality and to the south lies the North Wessex Downs Area of Outstanding Natural Beauty (AONB), a landscape of national importance and a considerable asset. The Swindon Joint Study (2005), that first informed the decision to allocate the area to the east of Swindon for development, identified that whilst there are few critical landscape areas within the Eastern Villages site itself, the area may be considered acceptable for development subject to it being sufficiently contained and constrained to protect the settings of Bourton, Wanborough and the AONB. Topographically, the site is located in an open landscape with gentle undulations and a localised high-point at Mount Pleasant Farm. Variations in topography across the area are subtle, enabling long views. Beyond the south of the site the land starts to rise on the escarpment of the Downs, signalling a very obvious change in landscape character. Previous adopted guidance has set out the characteristics of the wider area referred to as “Vale of the White Horse” which is described as a more remote landscape set apart from human activity. The guidance also seeks, where opportunities arise, additional tree planting in woodland blocks to help increase tree coverage of the area and support existing hedgerows. The Eastern Villages development site includes a network of watercourses amongst them the River Cole, its tributaries and associated flood risk zones. These river and stream routes draw meandering paths across the site forming field boundaries and influencing vegetation patterns. North east of Wanborough Road is located the Redlands Airfield. This grass runway airfield provides facilities for microlight flying, parachuting and skydiving. 2.1.3 Speed limits There are several speed limits (30, 40 and 60mph) currently in operation within the area under consideration for alternative EVSCR routes. These are shown on Drg Nos TH/SBCC/230/HIG/104 - 107 2.1.4 Lighting There is limited street lighting in the area of the EVSCR, mainly restricted to the Merlin Way and Commonhead junction areas. Wanborough Parish Council have previously expressed a preference for the village and surroundings to be unlit. 2.1.5 Parishes There are a number of parish councils on the route of or adjacent to the EVSCR 2.1.5.1 Parishes in Swindon Borough Council Bishopstone Covingham and Dorcan Liden, Eldene and Park South Stratton St Margaret and South Marston

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Wanborough 2.1.5.2 Parishes in Oxfordshire Bourton Shrivenham

2.1.5.3 Supplementary Planning Document (SPD) Parish consultation Swindon Borough Council has been working in partnership with representatives of the local communities during preparation of the SPD. South Marston Parish Council established a working party to work in partnership with the Borough Council specifically on the preparation of the South Marston SPD. South Marston, Wanborough and Bishopstone were also involved in the detailed aspects of the SPD including the consideration of flood risk, biodiversity, heritage and transport impacts. Bourton Parish Council have also been represented in Wanborough and Bishopstone Working Party meetings.

2.2 Land ownership and third parties Swindon Borough Council have provided CH2M Hill with details of existing landowners. A layout showing the approximate extent of land ownership and Land Registry title (where known) is provided on Drg No TH/SBCC/230/HIG/101.

2.3 Highways and structures 2.3.1 Highways The existing road network is predominantly rural in appearance with the road varying in width. This can be seen in Photos 1 Pack Hill, 10 & 23 The Marsh, 25 & 31 Wanborough Road. Further details on proposals are provided in Sections 2.5 and 4.

2.3.2 Structures Due to a period of inclement weather at the time of writing the report, it was not possible to undertake a full walkover survey of the site to determine the number of existing structures. Assessment of the existing mapping data has indicated that there are a number of small footbridges and access points over field drains, but the majority of these lie away from the corridor under consideration. Further details on proposals are provided in Section 5.

2.4 Surface Water Management The existing site is predominantly open farmland and as such the land is drained in a natural manner giving due regard to the topography and the underlying geology. Based on BGS Geological Mapping the underlying geology comprises Kimmeridge Clay, as further discussed in Section 2.6, which precludes the natural percolation of rainwater into the underlying substrata and results in pluvial flows across the site. The site encompasses the Liden Brook which flows in a northerly direction and discharges into the River Cole, the alignment of which passes through the northern element of the proposed development and to the south of the A420. The Liden Brook conveys the flows from a number of field drainage ditches which aid in the surface water management in the area of interest. During the site walk-over a system of ridge and furrows was observed which will further aid the management of surface water and could be associated with

2-4 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 2 2 EXISTING CONDITIONS the management of the meadows in the past. Despite the field drainage the land was observed to be waterlogged during the site walk-over and there was evidence of surface water ponding. The roads that bound the site, namely Pack Hill and Wanborough Road, are served by grips and roadside ditches (see Photos 18 and 19 for examples), which connect to the field drains and ultimately drain into the Liden Brook. The Liden Brook is culverted beneath Pack Hill and Wanborough Road. Due to the presence of the aforementioned watercourses, elements of proposed development site and associated EVSCR corridor lie within the bounds of the Environment Agency’s 0.1% and 1% annual probability flood maps, and is thus situated within Flood Zones 2 and 3, defined by Planning Policy Statement 25: Development and Flood Risk (PPS25) as having a medium to high probability of flooding respectively. Development within these areas is not encourage to ensure the functionality of the river catchment is maintained and flood risk is not transferred; and full compliance of the requirements of the National Planning Policy Framework (NPPF) will be sought during the planning process. Detail review of the flood risk and management of the surface water runoff along with the mitigation proposals is discussed in Section 6 of this report.

2.5 Transport and access

2.5.1 Existing Road Network The roads within the area under consideration for the EVSCR are varied in standard and character. Outline details are provided below and on Drg No TH/SBCC/230/HIG/102.

2.5.1.1 Pack Hill Pack Hill links the existing A4259 Marlborough Road / A419 dual carriageway / Purley Road grade separated junction (Commonhead roundabout) with the village of Wanborough. Pack Hill varies in speed limit with sections of 40mph, derestricted and 30mph limits between the A419 and Wanborough.

The road varies in width and section. From Commonhead roundabout to The Marsh the road is a kerbed single 2 lane 7.3m wide carriageway with no hard strips. East of The Marsh the road section reduces to a single carriageway 5.5m in width with 0.3m hard strips. There are no pedestrian/cyclist facilities. For details refer to Photos 1, 2 and 4.

2.5.1.2 The Marsh The Marsh links Pack Hill to Wanborough Road providing access to several residential and farm properties. The speed limit is derestricted at Pack Hill reducing to 30mph near Calder Vale / South View Cottages, remaining 30mph up to Wanborough Road.

This single carriageway unkerbed road varies between 4.8m – 5.5m in width with no hard strips. There are no pedestrian/cyclist facilities. The Marsh is used by equestrians, accessing fields from Pack Hill up to Bridleway 42 (Green Lane).

Typical details of The Marsh are shown on Photos 4, 8, 10, 11, 19, 21 and 23.

2.5.1.3 Wanborough Road Wanborough Road links the A420 junction onto the A419 dual carriageway with Wanborough village via Merlin Way. Wanborough Road is 30mph from Merlin Way to just east of Wanborough House. From here to

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 2-5 SECTION 2 2 EXISTING CONDITIONS the sewage work and allotments the road is derestricted (60mph) before reverting to 30mph in Wanborough village. This single carriageway road is approximately 6.0m wide. There is a section of footway on the southern side from Merlin Way to the Lotmead Farm and Business Village. The road is kerbed to just south of Lotmead. Typical details of Wanborough Road are shown on Photos 24, 25, 30 and 31.

2.5.2 Other Accesses

There are a number of other accesses to private properties that may be affected by the proposed EVSCR. These are:

Great Moor Leaze Farm, Meadow House, Moorleaze House Applegate House and Inlands Farm, Inlands Bungalow Property A (property name to be confirmed) – gains direct access off the A419 dual carriageway Wick Lane (leading to Thames Water pumping station)

Individual field access points are not listed above.

2.5.3 Public Transport

2.5.3.1 Thamesdown Transport Thamesdown Transport currently operate two routes which will be affected by the proposed EVSCR Route 46A Swindon – Hungerford (operated under contract to Wiltshire County Council) Route 48A Swindon – Marlborough (operated under contract to Wiltshire County Council) These routes operate on Monday to Saturday.

2.5.3.2 Goride CIC Goride currently operate one route which will be affected by the proposed EVSCR Route 90 Newbury – Swindon (operated under contract to Swindon Borough Council) This route operates on Monday to Saturday.

2.5.3.3 Stagecoach Stagecoach do not currently operate routes that would be affected by the EVSCR.

2.5.3.4 Bus Stop locations The Marsh, Wanborough – outside Farncombe Burycroft, Wanborough – outside Cross Keys public house

For further details on public transport proposals refer to Section 10.

2.6 Geotechnical conditions The existing geotechnical conditions have been subject to a separate desk top study. Details of the study are provided in Section 7.

2-6 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 2 2 EXISTING CONDITIONS 2.7 Environmental conditions The existing environmental conditions have been subject to a separate study. Details of the existing environmental conditions are provided in Section 8. 2.7.1 Phase 1 Survey Due to the adverse weather conditions experienced over a period of time and the time of year at writing of the report it is recommended that a walkover survey of the site is undertaken from March 2014. Between October to March is considered to be sub-optimal time for a Phase 1 survey as much of the flora is still dormant. In order for the ecological survey to be as robust as possible for the feasibility study, a survey later in the year is recommended, or an initial Phase 1 followed by recommendations for a brief check on habitats later in the year. Much of the area under consideration is currently suffering from high watercourse levels and standing water.

2.8 Public utilities CH2M Hill issued scheme identification and preliminary inquiries (C2 notices) in February 2014 to public utilities companies under Section 84 of the New Roads and Street Works Act to identify the locations of existing utilities. The approximate extent and details are shown on Drg No TH/SBCC/230/103. For further details on existing utilities and works to them refer to Section 9.

2.9 Non Motorised Users 2.9.1 Existing Footway / Cycleway Provision There is currently limited provision for pedestrians, cyclists and equestrians on the existing local road network. There is a small section of footway (approximately 1.5m wide) to the south side of Wanborough Road between Merlin Way and Lotmead Farm and Business Village. South of the site, there is a shared footway/cycleway linking the A4259 Marlborough Road, Commonhead Roundabout and terminates on the B4192 Purley Road – see photographs 39 and 40.

2.9.2 Footpaths and Bridleways There are a number of Swindon Borough Council footpaths that cross the alignment of the proposed EVSCR. A bridleway links The Marsh / Burycroft and Rotten Row in Wanborough. The location and approximate alignment of these footpaths and bridleway is shown on Drg No TH/SBCC/230/HIG/102. For further details on proposals for pedestrians, cyclists and equestrians refer to Section 11.

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SECTION 3 3 Scheme Development

3.1 Introduction A number of scheme options have been identified and considered as part of this work, which are described and assessed as part of this Report. This section provides a summary of the work undertaken.

3.2 Need for the Scheme The Eastern Villages is a proposed large mixed use development east of the A419 which, if permitted, may be developed in phases over a period of about 15 years. As part of the Eastern Villages development, a defined packages of highway measures have been identified that will need to be implemented when certain phases of the development are reached. These will be required whether it is development access on to the highway network or capacity issues at junctions along key corridors that are used by Eastern Villages traffic. The Lotmead and Earlscourt development phase (2300 dwellings) is large and requires an additional access point - this will be the Eastern Villages Southern Connector Road. It is predicted that 33% of peak period development traffic will use the new link road to the Commonhead roundabout. To enable this development, the EVSCR ( also referred to as Commonhead Link) between the southern limit of the development and the A419 Commonhead Roundabout at Pack Hill would be required to give access for the construction and occupation of some phases of the development. The purpose of this link will be to serve local access only and not to provide a route for strategic trips from the A419 to Acorn Bridge.

3.2.1 Eastern Villages & Masterplan The Eastern Villages Draft Supplementary Planning Document identified that the development of the new Eastern Villages must accord with the principles established in Swindon Borough Council Policy DE1 in order to create a high quality, well designed development fit for purpose now and for the future. The Eastern Villages must deliver high quality, attractive and successful public spaces throughout, relating to both the built and natural environment. The public realm, including public spaces, streets, pedestrian routes and cycle ways and the safeguarded Wilts & Berks Canal corridor must be attractively designed and constructed with high quality and durable materials. These principles will be applied to the design and development of EVSCR. The Eastern Villages will be predominantly residential arranged across the site in a series of discrete but interrelated villages. They will comprise approximately 1,500 dwellings located at Rowborough - a new village north of the A420, 500 new homes at an extension to South Marston, and approximately 6,000 dwellings across the wider Eastern Villages area south of the A420. The development will also provide a District Centre, retail, employment and schools for the local area.

3.3 Summary of Previous Work Previous studies have been undertaken for the main Eastern Villages development proposals and as part of the development of the Swindon Borough Council future development framework and Local Plan. These documents are listed below in Table 3-1

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TABLE 3-1 Summary of Previous Related Work

Information Title Published By Date

Plan Flood Map – Slice A Envirocheck 26 March 2008

Plan Flood Map – Slice B Envirocheck 26 March 2008

Report Geology 1:50,000 Maps – Slice A Envirocheck 26 March 2008

Report Geology 1:50,000 Maps – Slice B Envirocheck 26 March 2008

Report Regional Unexploded Bomb Risk - Wiltshire Zetica September 2009

Report Swindon Eastern Villages Transport Study JMP Consultants Ltd April 2011

Report Swindon Eastern Villages Transport Study – Update Report JMP Consultants Ltd December 2012

Report Swindon Borough Council Local Development Framework Swindon Borough Council July 2013 Eastern Villages Draft Supplementary Planning Document

Report Swindon Borough Local Development Framework Swindon Borough Council March 2011 Swindon Borough Core Strategy and Development Management Policies 2026 Swindon: Planning for our future Revised Proposed Submission Document

Plan Swindon Borough Draft Local Plan 2026 Pre-Submission Swindon Borough Council June 2013 Proposals Map

3.4 Optioneering The previous reports for the Eastern Villages Transport Study and Swindon Borough Council Draft Local Plan 2026 Pre-submission did not identify specific route(s) for the EVSCR. The Transport Study and EVDSPD provided an indication of the approximate position of the EVSCR at the southern end of the development – see Figure 1 from the Draft Supplementary Development Plan below

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Commonhead Foxbridge Link / EVSCR

The EVDSPD has determined that there will be no new route for strategic trips from the A420 in the east to the M4 through the new Eastern Villages. In accordance with the Draft Supplementary Planning Document, a road link is to be provided between the new Eastern Villages and Commonhead roundabout during a later phase of the overall development, to provide connectivity to the Strategic Road Network. The purpose of this link will be to serve local access only and not to provide a route for strategic trips from the A419 to Acorn Bridge. Given the rural context of the route, such assessments will include measures to mitigate the impact in relation to noise, light and landscape impact. 3.4.1 Eastern Villages Highway Concept The Supplementary Development Plan indicates that the Eastern Villages development islands will be connected by a series of vehicular lines which in some cases will need substantial spans across the floodplain in accordance with the Environment Agency requirements. These crossings provide an opportunity to enhance the local distinctiveness of the development islands they serve and are to be of a sensitive design, balancing the need to address the landscape setting with the provision of easily accessible routes for public transport, pedestrians, cyclists and cars. Movement within the new Eastern Villages seeks to encourage sustainable travel behaviour from the outset of the development. Traffic will generally be spread across the new primary and local route networks to disperse flows. A comprehensive approach to the design of internal movement networks within each of the villages is required to ensure the result is a technically robust solution developed according to a well-formed hierarchy of streets relative to their function. Strategic trips will not be catered for within the local road network and developers will be required to ensure this through the design.

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Highways should not dominate the Eastern Villages development layouts, but rather provide a good level of accessibility and connectivity. All routes must contribute to the overall sense of place being locally distinct and this must be addressed through more detailed design quality management tools such as Design Codes or detailed Framework Plans. It is essential that all Eastern Villages development phases assess and mitigate the impacts of the existing road network. This is particularly important for the rural communities adjacent to the new Eastern Villages. 3.4.2 Constraints The following were identified as constraints in development of the recommended alignment

TABLE 3-2 Alignment Constraints

Approx Description Location Scheme Summary of Constraint Chainage

Significant Unscheduled Pack Hill Ch 0 Earthworks Archaeological Feature

Purley Road – Pack Restoration of the Wilts & Berks Canal between Eastern Wilts & Berks Canal Hill – Wanborough Ch 100 Villages, Commonhead and Wichelstowe Road

Pack Hill / The Great Moor Leaze Farm Ch 100 Local building of historical interest Marsh

Pack Hill / The Moorleaze House Ch 100 Property Marsh

Pack Hill / The The Dance Studio Ch 150 Property/ business Marsh

Pack Hill Ch 0 - 150 Access to Wanborough to be maintained

Applegate House, Inlands The Marsh Ch 800 Properties to remain. Access to be maintained. Bungalow, Inlands Farm

Flood Risk Zone Ch 900 - 1300 Minimum carriageway level to be maintained

Property A East of A419 Ch 1325 Property to remain. Access to be maintained.

Mature woodland area East of A419 Ch 1450 - 1750 Woodland to remain

Eastern Villages Ch 1300 - 2200 development

No direct access from EVSCR to Wanborough Road Wanborough Road Ch 2280 Roman Road Properties to remain

Wanborough Road Nationally significant former Roman settlement of Scheduled monuments northwest of Durocornovium EVSCR

Option generation work undertaken identified the following options to be considered:

3-4 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 3 3 SCHEME DEVELOPMENT 3.4.3 Design Speed 30mph/60kph Refer to Drg No TH/SBCC/230/HIG/104 for horizontal alignment options 3.4.3.1 Option 1 Alignment is acceptable but the 30mph speed limit in rural situation is likely to be exceeded. This alignment is in close proximity to the wooded area adjacent to the A419. The alignment reduces the development area between the EVSCR and the A419. The EVSCR is in closer proximity to the southbound A419. 3.4.3.2 Option 2 Alignment is acceptable but the 30mph speed limit in rural situation is likely to be exceeded. This creates more space around the wooded area and balances the developable area better. 3.4.3.3 Option 3 Alignment is acceptable but the 30mph speed limit in rural situation is likely to be exceeded. There is a longer straight section which could encourage higher speeds. 3.4.3.4 Option 4 Alignment will cause severance for Property A and leave this property isolated between the EVSCR and A419 dual carriageway. The 30mph speed limit in rural situation is likely to be exceeded. This alignment runs close to the safeguarded canal route, reducing areas for leisure opportunities associated with the canal.

3.4.4 Design Speed 40mph/70kph Refer to Drg No TH/SBCC/230/HIG/105 for horizontal alignment options 3.4.4.1 Option 1 Alignment is acceptable and provides a balance for developable area, distance from the wooded area and avoids taking land from the corner of Great Moor Leaze Farm. 3.4.4.2 Option 2 Alignment is acceptable and avoids crossing the future canal route but would require land-take in the corner of Great Moor Leaze Farm (historic local building) and removal of mature trees (see Photo 7) 3.4.4.3 Option 3 Alignment has a longer straight section which will encourage higher speeds and passes close to the wooded area. 3.4.4.4 Option 4 This alignment has a longer straight section which could encourage higher speeds and isolates Property A between the EVSCR and the A419. However, this route is considered due to its avoidance of the 600mm diameter water supply main from Pack Hill and the Thames Water pumping station.

3.4.5 Design Speed 50mph/85kph Refer to Drg No TH/SBCC/230/HIG/106 for horizontal alignment options 3.4.5.1 Option 1 Alignment is generally acceptable but is in close proximity to the wood adjacent to the A19. The design is to encourage a reduced speed limit between Pack Hill and the Eastern Villages – use of 50mph over this section will not achieve this.

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 3-5 SECTION 3 3 SCHEME DEVELOPMENT 3.4.5.2 Option 2 Alignment is acceptable but would require land-take in the corner of Great Moor Leaze Farm and removal of mature trees (see Photo 7). The design is to encourage a reduced speed limit between Pack Hill and the Eastern Villages – use of 50mph over this section will not achieve this. 3.4.5.3 Option 3 Alignment encourages higher speeds to/from Commonhead Roundabout 3.4.5.4 Option 4 Alignment is generally acceptable but is would not form a central spine road to the Eastern Villages development. The design is to encourage a reduced speed limit between Pack Hill and the Eastern Villages – use of 50mph over this section will not achieve this.

3.4.6 Design Speed 60mph/100kph Refer to Drg No TH/SBCC/230/HIG/107 for horizontal alignment options 3.4.6.1 Option 1 This alignment would permit high speeds to be achieved between Commonhead Roundabout and Wanborough Road area through the Eastern Villages development. The design is to encourage a reduced speed limit between Pack Hill and the Eastern Villages – use of 60mph over this section will not achieve this. The road does not form a central spine road to the development. 3.4.6.2 Option 2 Alignment is generally acceptable and would be more successful in reducing speeds than Option 1 but encroaches into the woodland area adjacent to the A419. 3.4.6.3 Option 3 Alignment is generally acceptable and would be more successful in reducing speeds than Option 1 but encroaches into the woodland area adjacent to the A419 and would require land-take in the corner of Great Moor Leaze Farm and removal of mature trees (see Photo 7). 3.4.6.4 Option 4 This alignment would require taking of Great Moor Leaze Farm (local building of historic interest) and The Dance Studio. The alignment would permit high speeds to be achieved between Commonhead Roundabout and the Eastern Villages development.

TABLE 3-3 Summary of Highway Options considered Design Speeda Progressed Option Ref Drg No Reason mph/kph (Yes/ No)

Alignment is acceptable but the 30mph speed limit in 1 No rural situation is likely to be exceeded.

Alignment is acceptable but the 30mph speed limit in 2 No rural situation is likely to be exceeded.

Alignment is acceptable but the 30mph speed limit in 30 / 60 3 TH/SBCC/230/HIG/104 No rural situation is likely to be exceeded.

Alignment will cause severance for Property A and leave this property isolated between the EVSCR and 4 No A419 dual carriageway. The 30mph speed limit in rural situation is likely to be exceeded.

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TABLE 3-3 Summary of Highway Options considered Design Speeda Progressed Option Ref Drg No Reason mph/kph (Yes/ No)

This alignment avoids taking land in the corner of Great Moor Leaze Farm, creates an alignment which will slow down vehicles approaching the Eastern Villages 1 Yes development, avoids severance of Property A, provides clearance to the wooded area and a central access to the Foxbridge development

Alignment is acceptable but would require land-take in 40 / 70 2 TH/SBCC/230/HIG/105 No the corner of Great Moor Leaze Farm and removal of mature trees.

This alignment avoids taking land in the corner of Great 3 No Moor Leaze Farm but is closer to the wooded area.

This alignment avoids taking land in the corner of Great Moor Leaze Farm, avoids the Thames Water 600mm dia 4 Yes water supply main, provides clearance to the wooded area and a central access to the Foxbridge development

Alignment is generally acceptable but is in close proximity to the wood adjacent to the A19. The design 1 No is to encourage a reduced speed limit between Pack Hill and the Eastern Villages – use of 50mph over this section will not achieve this.

Alignment is acceptable but would require land-take in the corner of Great Moor Leaze Farm and removal of 2 No mature trees. The design is to encourage a reduced 50 / 85 TH/SBCC/230/HIG/106 speed limit between Pack Hill and the Eastern Villages – use of 50mph over this section will not achieve this.

Alignment encourages higher speeds to/from 3 No Commonhead Roundabout

Alignment is generally acceptable but is would not form a central spine road to the Eastern Villages 4 No development. The design is to encourage a reduced speed limit between Pack Hill and the Eastern Villages – use of 50mph over this section will not achieve this.

This alignment would permit high speeds to be achieved between Commonhead Roundabout through the Eastern Villages development. The design is to 1 No encourage a reduced speed limit between Pack Hill and the Eastern Villages – use of 60mph over this section will not achieve this. The road does not form a central spine road to the development – Option A

Alignment is generally acceptable and would be more 60 / 100 TH/SBCC/230/HIG/107 successful in reducing speeds than Option 1 but 2 No encroaches into the woodland area adjacent to the A419.

Alignment is generally acceptable and would be more successful in reducing speeds than Option 1 but 3 No encroaches into the woodland area adjacent to the A419 and would require land-take in the corner of Great Moor Leaze Farm and removal of mature trees.

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TABLE 3-3 Summary of Highway Options considered Design Speeda Progressed Option Ref Drg No Reason mph/kph (Yes/ No)

This alignment would require taking of Great Moor Leaze Farm (local building of historic interest) and The 4 No Dance Studio. The alignment would permit high speeds to be achieved between Commonhead Roundabout through the Eastern Villages development – Option B a Design Speed based upon TD 9/93 Highway Link Design Tables 2 and 3

3.4.7 Pack Hill widening In the JMP Swindon Eastern Villages Transport Study Report (April 2011), widening of the Pack Hill approach to Commonhead roundabout was identified. This is to accommodate the increased traffic volume expected from the EVSCR. A schematic layout of the proposed widening of Pack Hill is shown on Drg No TH/SBCC/230/150. The widening would reduce potential queuing on Pack Hill and make better use of future layout changes recommended for Commonhead roundabout. 3.4.7.1 Archaeological feature Approximately 60m east of the widening, there is a Significant Unscheduled Archaeological Feature which requires protection under the Swindon Borough Council Local Plan Policy EN10. This is separated from the widening by the Liden Brook. If it is decided to progress with the Pack Hill widening, it will be necessary to undertake a detailed desk- based assessment to review the archaeological background to the study area and the historic landscape, and to form a preliminary view of archaeological potential in the affected area. This would also consider issues such as the settings of Listed Buildings in consultation with the Swindon Borough Council Conservation Officer and in accordance with the National Planning Policy Framework (NPPF). This would be followed by field evaluation, if required, in consultation with the Conservation Officer. These investigations will be undertaken to inform planning determination.

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4 Highways

4.1 Proposed Eastern Villages Southern Connector Road 4.1.1 Introduction The proposed Eastern Villages Southern Connector Road would be provided between the new Eastern Villages development and Commonhead roundabout during a later phase of the overall development. The purpose of this link will be to serve local access only and not to provide a route for strategic trips from the A419 to Acorn Bridge. CH2M Hill have prepared a draft Eastern Villages Phasing / Trigger Point Development Testing report for Swindon Borough Council. The purposes of this report is to identify trigger points for transport mitigation to accommodate traffic generated when the various land parcels within the Eastern Villages development are added to the network, then to ascertain the impact each land parcel has on critical parts of the road network. The focus of the report is to identify which highway infrastructure is required to mitigate against the impact of the eight phases of the Eastern Villages development. One of the transport mitigation items is the link from the south of the development to the Commonhead roundabout.

CH2M Hill have prepared a Mitigation West of A419 and Apportionment of Impact report for Swindon Borough Council. The purposes of this report is to ascertain the impact each land parcel has on critical parts of the road network. The focus of the report is to identify which highway infrastructure is required to mitigate against the impact of the eight phases of the Eastern Villages development. One of the transport mitigation items is the link from the south of the development to the Commonhead roundabout.

This feasibility report will present proposals including alternative route options identify the preferred routes connection into the existing local road network provision of access to existing properties requirements of pedestrians, cyclists and equestrians associated infrastructure requirements

4.2 Speed limit proposals The existing road speed limits are a variety of 30, 40 and 60mph – see Drg No TH/SBCC/230/HIG/102. Currently The Marsh is derestricted (60mph) from Pack Hill to north of Applegate House. It is proposed to apply a 40mph speed limit to the EVSCR between Pack Hill and the Eastern Villages southern boundary. Within the development the speed limit will drop to 30mph being a future residential area. This will have the advantage of: reducing the speed limit in areas of a number of farm accesses, residential accesses and equestrians; reducing speed on the approach to the Eastern Villages residential area; provide consistency with the other local speed limits of 30/40mph including the recently introduced 40mph on Wanborough Road; permit installation of pedestrian refuges in crossing points; permit tighter geometry in areas of constraints;

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reduce land take;

There is a recently created section of 40mph speed limit on Wanborough Road between Burycroft and the EVSCR crossing point. This section could remain as part of the proposals as this forms a gateway into Wanborough at the southern end of the speed limit. For details of the proposed speed limits refer to Drg No TH/SBCC/230/HIG/109. 4.3 Highway alignment 4.3.1 Horizontal alignment design parameters The horizontal alignment has been designed in accordance with national standard TD9 Highway Link Design Table 3 and Section 3 and Swindon Borough Council guidance. The horizontal alignment radius was selected based on the proposed design speed in accordance with the requirements of TD9 Table 3. 4.3.2 Horizontal alignment constraints Horizontal alignment constraints have been considered in Section 3.4.2. 4.3.3 Vertical alignment design parameters The vertical alignment has been designed in accordance with national standard TD9 Highway Link Design Table 3 and Section 4 and Swindon Borough Council guidance. Minimum longitudinal gradient (single carriageways) = 1% Maximum longitudinal gradient (single carriageways) = 6% Crossfall and superelevation was designed in accordance with the requirements of TD9 Table 3. These values are related to the horizontal alignment radius to assist travelling on curves. 4.3.4 Vertical alignment constraints The highway vertical alignment is constrained by several factors: Drainage of EVSCR by gravity drainage using gullies rather than combined kerb and drainage blocks Drainage to discharge to swales where possible to provide a sustainable urban drainage system Ch 240 – high point to provide gravity drainage and The Marsh junction is to be located at the high spot for visibility purposes Ch 490 – low point to provide gravity drainage Ch 850 - low point to provide gravity drainage outside of Flood Risk Zone Ch 1045 – minimum carriageway level set from 1in 100 year flood level Ch 980 – 1300 – area within Flood Risk Zone Ch 1650 - low point to provide gravity drainage Ch 2250 – low point to provide gravity drainage prior to Wanborough Road (at grade Options A1 and A2) Ch 2260 – low point in underpass – pumping station will be required (Option A4)

Indicative vertical alignments for the different options are shown on Drg Nos TH/SBCC/230/HIG/120 – 126. Approximate heights of the new road in relation to the surrounding areas are shown on Drg No TH/SBCC/230/HIG/119.

4-2 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 4 4 HIGHWAYS 4.4 The Marsh junction 4.4.1 Introduction The Marsh is currently used by a variety of motorised (cars, vans and buses) and non-motorised users (pedestrians, cyclists and equestrians). As part of the proposed EVSCR, it will be necessary to sever the current layout of The Marsh with the new alignment. To maintain access to properties and Wanborough it will be necessary to construct a new junction. 4.4.2 Junction format The junction format was determined in accordance with Figure 2/2 of TD42 Geometric Design of Major / Minor Priority Junctions. Although traffic flows on The Marsh are to be confirmed, a simple T-junction would be appropriate in this location. A suitable stopping sight distance to vehicles waiting to turn at the junction on the northbound approach from Pack Hill is available. 4.4.3 The Marsh The Marsh would be severed and realigned for the EVSCR. A new access point for The Marsh will be provided. The remaining section of The Marsh south of the EVSCR would be left in place to facilitate access to the adjacent fields. To assist, a turning head would be provided at an agreed location. 4.5 Anti-glare screening Anti-glare screening can be particularly effective alongside fast major roads which have an adjacent minor road where, in darkness, opposing headlamps on the nearside cause confusion. At rural locations where swept headlamp paths persistently cross drivers’ vision, short lengths of anti-glare screening may be considered. The purpose of an anti-glare screen or barrier is to cut off light from oncoming vehicle headlights. They must be designed so that light directed towards the driver at oblique angles (12° to 20°) is reduced whilst relatively open vision (around 70°) is maintained in the sideways direction. The height to effectively screen headlight glare from all types of vehicles on level ground is 2.0 m. At this stage the use of anti-glare screening has not been progressed further and options for reducing or eliminating glare should be investigated at a later date. 4.6 Wanborough Road 4.6.1 Introduction One of the main areas to address is the point where the EVSCR would cross Wanborough Road between the A419 and Wanborough. The crossing point options were prepared so that no access from the EVSCR to Wanborough Road was possible (by physical separation) or permitted (banning of turning movements). Details of these proposals and constraints are identified below. 4.6.2 Constraints The main constraints at the crossing point of the EVSCR and Wanborough Road are Wanborough House stables approximately 160m south-east of Wanborough House intermediate pressure gas main fibre optic telecommunication cables To maximise the distance of the crossing point from Wanborough Road it would be necessary to relocate the stables area. It is likely that diversion / protection of the intermediate pressure gas main on the north side of would be more disruptive than diverting /protecting the fibre optic cables to the south side of Wanborough Road.

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Subject to geometric constraints, widening to the south side of Wanborough Road is thought to be preferable to symmetric widening on both sides of the carriageway. Photographs 30 and 31 show the approximate position of the crossing point on Wanborough Road 4.6.3 Wanborough Road crossing point options Four main options were considered where the EVSCR crosses Wanborough Road: Option A1: Simple cross roads with prohibited turning movements Option A2: Signalised junction with prohibited turning movements Option A3: Wanborough Road overbridge Option A4: Wanborough Road underpass

4.6.3.1 Option A1: Simple cross roads with prohibited turning movements The use of at grade crossing points whilst cheaper, makes enforcement of the prohibited turns between Wanborough Road and the EVSCR difficult. Refer to Drg No TH/SBCC/230/HIG/115 for details of indicative layout. The potential future location of a new Wiltshire Fire and Rescue Service (WFRS) fire station and ambulance standby point south of Foxbridge village would need to be considered in the final layout as there may be a requirement for hardened areas for emergency access links. This should be such as to discourage non- emergency drivers. Consultations at preliminary design stage should be undertaken with the emergency services. Wanborough Road should be made the priority road through the junction to maintain the existing layout, flows and make the turn from the EVSCR less attractive. Provision of clear information and warning signing of the junction would be required. Signing of prohibited movements is essential as this would be an unlit rural cross-roads junction until the main development commenced. This would be less safe than a signalised junction. Photos 30 and 31 show the approximate location of the proposed crossing point on Wanborough Road. The existing stables that would need to be relocated are shown on Photo 29. The existing landscape where the EVSCR would cross is shown in Photos 27, 28 and 32. 4.6.3.2 Option A2: Signalised junction with prohibited turning movements The use of at grade crossing points whilst cheaper, makes enforcement of the prohibited turns between Wanborough Road and the EVSCR difficult. Refer to Drg No TH/SBCC/230/HIG/116 for details of indicative layout. The potential future location of a new Wiltshire Fire and Rescue Service (WFRS) fire station and ambulance standby point south of Foxbridge village would need to be considered in the final layout as there may be a requirement for hardened areas for emergency access links. This should be such as to discourage non- emergency drivers. Consultations at preliminary design stage should be undertaken with the emergency services. Provision of clear information and warning signing of the junction would be required. Signing of prohibited movements is essential as this would be an unlit rural cross-roads junction until the main development commenced. Photos 30 and 31 show the approximate location of the proposed crossing point on Wanborough Road. The existing stables that would need to be relocated are shown on Photo 29. The existing landscape where the EVSCR would cross is shown in Photos 27, 28 and 32.

4-4 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 4 4 HIGHWAYS 4.6.3.3 Option A3: Wanborough Road overbridge The construction of a bridge over Wanborough Road will ensure that traffic from the Eastern Villages development is separated from local Wanborough Road traffic. Indicative layout and sections are shown on Drg Nos TH/SBCC/230/HIG/118 and /125. The earthworks are based on a batter of 1 in 6 to help them to blend easier into the surroundings. The approximate height of the new embankment and bridge in relation to the surrounding areas is shown on Drg No TH/SBCC/230/HIG/119. A bridge for the EVSCR over Wanborough Road would raise several issues: visual intrusion - the area surrounding Wanborough Road is generally of flat even topography with little undulation presumably arising from its land use for arable and pastoral farming. The carriageway and parapet for a new structure over Wanborough Road would be approximately 8m above existing levels – higher than the A419 dual carriageway. Approach ramps to the structure would be in the region of 120m long on each side. Depending on the landscaping batter, the earthworks could extend as much as 50m from the centreline of the new EVSCR. Wilts & Berks Canal – it is likely that the embankment north of Wanborough Road would need to be extended to cross the canal. This is not discussed in this report, but has been considered during development of the vertical alignment. noise – construction of the structure would increase the noise levels compared to an at-grade option and for a long duration cost – the cost of the structure with associated earthworks and landscaping would be greater than an at- grade junction construction period – the construction period would be extended compared to the at-grade option. It is assumed that the Redlands Airfield will not be operating at the time of construction (subject to a legal agreement that extinguishes the airfield planning permission), so issues associated with conflict between the structure and flight paths are discounted at this stage. The structure abutment can be designed such that it is built in isolation way from Wanborough Road minimising disruption. Photos 30 and 31 show the approximate location of the proposed crossing point on Wanborough Road. The existing stables that would need to be relocated are shown on Photo 29. The existing landscape where the EVSCR would cross is shown in Photos 27, 28 and 32.

4.6.3.4 Option A4: Wanborough Road underpass The construction of an underpass at Wanborough Road will ensure that traffic from the East Villages development is separated from the local Wanborough Road traffic. Indicative layout and sections are shown on Drg Nos TH/SBCC/230/HIG/117 and /126. Construction of an underpass beneath Wanborough Road would have a smaller footprint than an overbridge. A pedestrian route through the underpass would be provided. Due to the narrower footway width, cyclists would need to dismount on the approach. Its appearance would not be in keeping with the longer term aspirations of the Eastern Villages. Some low level lighting would be required in the underpass section. Geometrically, the underpass would need to rise north of Wanborough Road to pass over the future canal. Longer term considerations include the provision of a pumping station to remove highway drainage. This has associated increased maintenance costs.

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Typical underpass constructions types include cut and cover, jacked and bored and are used in different circumstances. cut and cover underpass – the existing ground is excavated and tunnel sections installed prior to backfilling. This would require either a long term closure of Wanborough Road or a temporary diversion road constructed in the adjacent fields. There are issues with intermediate pressure gas main and fibre optic cables along Wanborough Road to consider. jacked underpass – precast concrete sections are pushed through the existing ground under hydraulic pressure after excavation at the front. This would be less disruptive to the local road network but would still need to provide protection to the intermediate pressure gas main and fibre optic cables bored underpass – use of tunnel boring machine to create the void and constructed with precast concrete segments. This would be less disruptive than cut and cover but is more dependent on existing ground conditions than a jacked option. Again this would need to provide protection to the intermediate pressure gas main and fibre optic cables The cut and cover underpass would be the preferred option of the three. This would provide simpler construction certainty on the issues with the intermediate pressure gas main and fibre optic telecommunications reduced construction period reduced cost Photos 30 and 31 show the approximate location of the proposed crossing point on Wanborough Road. The existing stables that would need to be relocated are shown on Photo 29. The existing landscape where the EVSCR would cross is shown in Photos 27, 28 and 32. 4.6.3.5 Wanborough Road staggered cross-roads This option was discounted as it does not provide restrictions on movements between Wanborough Road and the EVSCR 4.6.3.6 Wanborough Road roundabout This option was discounted as it does not provide restrictions on movements between Wanborough Road and the EVSCR 4.6.4 Preferred crossing point options There are two preferred EVSCR / Wanborough Road crossing point options: Option A2 signalised crossing point - £11.6M (with equestrian route) Option A4 underpass - £13.9M (with equestrian route)

TABLE 4-1 Layout Option Summary

Option A4 underpass Option A2 signalised crossing point Benefits Disadvantages Benefits Disadvantages less land take than more land required reduce the costs will need monitoring overbridge compared to signalised associated with the and enforcement

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TABLE 4-1 Layout Option Summary

Option A4 underpass Option A2 signalised crossing point Benefits Disadvantages Benefits Disadvantages less visual intrusion crossroads work signals not in keeping than overbridge with local surroundings increased structure less land take than reduced costs extent overbridge or compared to underpass lighting of underpass overbridge required for be less disruptive to guarantees separation pedestrians users of Wanborough of traffic from Road safety barrier required Wanborough Road less visually intrusion increased cost over Wanborough Road will than an overbridge or signalised crossroads have similar underpass appearance to existing more construction have lower noise disruption to pollution than an pedestrians and cyclists Wanborough Road can be separated from overbridge compared to signalised Wanborough Road crossing point be safer than an

increased maintenance uncontrolled cross road and potential for arrangement flooding if pumping no safety barrier station fails required increased risk to gas no risk of flooding mains during reduced risk to gas construction mains during construction

If funding is available then Option A4 would be preferred. If not, then the signalised crossroads (Option A2) should be considered further.

4.7 Commonhead roundabout The Commonhead roundabout provides an access point onto the A419 dual carriageway trunk road for: A4259 Marlborough Road (dual carriageway); Purley Road (single carriageway); Pack Hill (single carriageway). The Commonhead junction suffers congestion associated with the flows from the A419 and A4259 and the lane reduction on the roundabout circulatory carriageway. Introducing the EVSCR provides an alternative access into the Eastern Villages development, and reduces traffic and congestion at the A419 / A420 White Hart junction. However, increased traffic is experienced at the Commonhead junction, including an increase in queuing on Pack Hill and also on B4192 Purley Road, as these vehicles have to give way to additional Pack Hill traffic. The

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JMP Transport Study identified the requirement to increase the capacity of Pack Hill to accommodate the additional traffic through the introduction of the EVSCR, the number of lanes on the approach to the roundabout would need to be increased to two. The roundabout southern circulatory carriageway would be increased to two lanes from one lane at a later date. Indicative details of the proposed widening of the Pack Hill approach are shown on Drg No TH/SBCC/230/HIG/150. It is proposed to provide a footway/cycleway link on the western side of the EVSCR from Wanborough Road to tie in at Commonhead Roundabout. Photographs 36 – 41 show the area around Commonhead junction including the existing footway/cycleway. 4.8 Street lighting 4.8.1 Existing street lighting Currently there is limited street lighting in the area. This is generally restricted to the areas around A419 southbound slip / Pack Hill and the residential area at Merlin Way. There is street lighting in Wanborough but this is limited to the new developments along Magdalen Road and The Beanlands. It is Wanborough Parish Council’s wish to limit street lighting so as to maintain the rural village feel. The extents of the existing lighting are shown on Drg No TH/SBCC/230/HIG/102. 4.8.2 Lighting requirements 4.8.2.1 Highways No lighting is proposed for the EVSCR. As part of the Eastern Villages development, lighting will be installed at a later date between the southern boundary and Wanborough Road. No lighting is proposed where the EVSCR crosses Wanborough Road for at-grade (A1 and A2) or overbridge (A3) options. If an underpass solution (Option A4) was adopted then there would be a need for low level lighting in the structure section and lighting on the approaches for pedestrians and cyclists. 4.8.2.2 NMU routes The provision of lighting for NMUs should largely be based upon local circumstances. In urban areas, it is recommended that where appropriate and feasible, routes should be lit, particularly at crossing points. Consultation may be required to assess appropriateness. NMU routes in rural areas should not normally include lighting unless there are specific requirements, which include: high flows of NMUs, particularly on adjacent and shared use NMU facilities; routes with intersections with rights of way and both minor and major roads falling below geometry standards (lighting used at a specific point to highlight danger); routes which form part of an identified school route, commuter route or other route; through any underpass (subject to environmental impact). Consideration needs to be given to the need for, and level of, landscaping in the vicinity of NMU routes. Such landscaping should be sympathetic to the required security of the route. Additionally, routes that are not maintained can cause security problems if the vegetation is not regularly cut back. Vegetation adjacent to the route should be maintained to an appropriate height to minimise the number of hiding places; this is likely to be of particular concern in urban/suburban areas. At feasibility stage, it is assumed that the level of NMU usage will not require lighting provision under options A1, A2 and A3 because: levels of NMUs are expected to be relatively low the footway /cycleway will be adjacent to the EVSCR

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route will comply with geometric standards adjacent embankments will have a relatively shallow batter (1 in 6) areas of landscaping providing concealment are not anticipated A NMU route through an underpass (Option A4) would need to be lit through the structure and on its approaches. Screening of the underpass area could reduce light pollution. 4.9 Traffic Flow Assessment 4.9.1 Traffic Flows The new link road would provide connectivity to the Strategic Road Network at Commonhead junction for the A419 and M4. The purpose of this link will be to serve local access only and not to provide a route for strategic trips from the A419 to Acorn Bridge. The Lotmead and Earlscourt development phase (2300 dwellings) will require an additional access point. The new EVSCR to the Commonhead roundabout would be used by 33% of the peak period development traffic. Preliminary modelling of the projected traffic figures for the EVSCR indicates that the peak hourly traffic flow will be 464 vehicles in one direction, with an annual average daily traffic flow of 2614 vehicles.

4.10 Carriageway pavement and foundation design 4.10.1 Typical Pavement Construction The indicative pavement and foundation construction have been designed in accordance with the requirements of national standards HD24 Traffic Assessment, IAN 73 Rev 1 Design of Pavement Foundation and HD26 Pavement Design. Due to the alignment of the road, it will be necessary to ensure that the underside of the granular sub-base layer is a minimum 600mm above the predicted 1 in 100 year flood level. Underlying capping layers will need to be more permeable than the sub-base layer. This will avoid requirements to drain the sub-base layer in areas of inundation. If the sub-base becomes saturated this will weaken the pavement construction leading to failure. On site testing during the preliminary / detailed design phase will determine the strength of the underlying foundation soil type and provide an indication of the CBR value for use in the design. Constructed embankments will achieve a high CBR value through compaction, so the extent of capping in these locations can be reduced or removed.

TABLE 4-2 Typical Pavement Construction Thicknesses

Pavement Layer Material 2% CBR 4% CBR 5% CBR

Surface course Cl 924 TSCS (10mm) 40 40 40 40 40

Binder course AC 20 Dense Bin 40/60/des 60 60 60 60 60

Base course AC32 Dense Base 40/60 des 100 100 100 100 100

Foundation

Sub-base only Cl 803 Granular Type 1 sub-base - 370 - 240 -

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TABLE 4-2 Typical Pavement Construction Thicknesses

Pavement Layer Material 2% CBR 4% CBR 5% CBR

Cl 803 Granular Type 1 sub-base 360 - 270 - 220 Capping & sub- base Class 6F2 capping 260 - 225 - 210

Total Pavement Thickness (mm) 820 570 695 440 630

Finished Road Level Above 1 in 100 Year Flood Level (mm) 1160 870 770 740 720 Sub-base layer 600mm flood level

All material thicknesses in millimetres

Pavement construction depth would be refined during preliminary and detailed design with potential reduction in overall thicknesses and heights of embankment where possible. 4.11 Carriageway width and cross-section 4.11.1 Existing Road Widths The existing road widths measured on site were Pack Hill near to The Marsh – 7.3m single carriageway – see Photo 1 The Marsh – 5.5m reducing to 4.8m single carriageway – see Photos 8, 10, 11 and 21 Wanborough Road – 6.0m single carriageway- see Photos 30 and 31

4.11.2 Proposed road width and cross section 4.11.2.1 Proposed road width The EVSCR will be in two distinct sections rural from Pack Hill to EVSCR boundary urban residential from EVSCR boundary to Wanborough Road Currently Pack Hill, The Marsh and Wanborough Road have distinctly rural appearance so it is the proposed that the EVSCR maintains this appearance and character between Pack Hill and the EVSCR southern boundary. From this boundary to Wanborough Road, the road will change in character to urban residential. The surroundings will be designed in accordance with Manual for Streets when the development tis undertaken. Traffic flows (464 veh/hr at the peak) indicate that the carriageway road width should be 6.1m. This takes into consideration the following criteria for purposes of the feasibility study: it is in keeping with Swindon Borough Council proposals that the development spine road width is limited to 6.1m; reduced road width provides the route with rural appearance and reduces speeds; geometry of EVSCR is designed to a lower speed limit and lower radii than The Marsh; The Marsh forms part of a bus route. These will be diverted along part of the EVSCR; potential siting of a new fire station and ambulance stand-by point; pedestrians and cyclists will be provided with a shared route taking them off-carriageway; equestrians will be provided with a separate verge area to use taking them off-carriageway Refer to the typical sections on Drg Nos TH/SBCC/230/HIG/140 - /143 for further details.

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4.11.2.2 Footway / cycleway The proposed shared footway/cycleway is to be 3.0m in accordance with TA90. A separation zone of 0.5m would be provided between the carriageway and footway/cycleway. This would provide a paved area width west of the carriageway of 3.5m. It is proposed that this is formed from a distinctive surfacing so that delineates the boundary area. This is often done in Swindon Borough using a strip of green coloured surfacing. Small widths of verge are often prone to loss of grass as they dry out and create maintenance issues. As the embankment slopes are to be flatter than 1 in 3, there is no requirement to provide separation between the footway/cycleway and the batter. A 2.0m wide pedestrian route would be provided through an underpass under Option A4. Cyclists would be required to dismount on the approach to the underpass so as to reduce the size of the structure and cost. Refer to the typical sections on Drg Nos TH/SBCC/230/HIG/140, /141 and /142 for further details.

4.11.2.3 Equestrian route Following discussions with Swindon Borough Council Rights of Way, a demand for an equestrian route between Wanborough Road and Pack Hill has been identified. The usage of this route would need to be quantified at preliminary design stage so as to confirm specific requirements for an equestrian route. If provided, this equestrian route could be 3.0m wide allowing 2 horses to pass in accordance with TA90. Similarly to footway/cycleways, a separation zone between the equestrian route and the carriageway would be required. This would be 1.8m, creating an overall eastern verge width of 4.8m. As the embankment slopes are to be flatter than 1 in 3, there would be no requirement to provide separation between the equestrian route and the batter. Until a requirement for an equestrian route is confirmed, the verge to the east of the EVSCR would be limited to 1m in width. Refer to the typical sections on Drg Nos TH/SBCC/230/HIG/140 and /141 for further details.

4.12 Road Restraint Systems (RRS) 4.12.1 Requirements for Provision of RRS National guidance on the provision of road restraint systems (safety barriers and pedestrian guardrailing) is set out in TD19 Requirement for Road Restraint Systems. This standard has been developed and produced for use on the Trunk Road network. These roads form a strategic road network of typically dual or high standard single carriageways, carrying high volume and/or high-speed traffic (i.e. with speed limits of 50 mph or more). RRS must also be provided on the Trunk Road network where the Design Speed or Imposed Speed Limit is less than 50mph and it is considered such provision is needed. A Road Restraints Risk Assessment Process (RRRAP) is applied to roads with speed limits of 50mph or higher. The RRRAP has not been developed to assess the risk from roadside hazards at speeds of less than 50 mph and/ or for traffic flows of less than 5,000 AADT. If the risk from roadside hazards, therefore, needs to be assessed at speeds of less than 50 mph or traffic flow of less than 5,000 AADT, then the following may be considered:

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Use the RRRAP at 50mph and the higher of the AADT for the road and 5,000 AADT, but use all other information from the site to aid any decision making about those road side hazards. It is recommended that a site inspection is carried out to ensure local hazards are considered that might fall outside the hazards included within the RRRAP. Carry out a separate risk assessment without the aid of the RRRAP and use the guidance and technical requirements to aid in the decision making process. For the purposes of the EVSCR Feasibility Study, it is proposed to apply the provision criteria set out in Section 3.12 (highways) and 4.4 (vehicle parapets) against perceived hazards. 4.12.2 Highways hazards requiring RRS protection

In accordance with Section 4.4 of TD19, the following highway hazards have been assessed as potentially requiring RRS protection: Above ground structural supports, bases or foundations which are positioned less than 3 m above the adjacent paved carriageway Drainage culvert headwall. Embankments and vertical drops Environmental noise barriers or screens Highway boundary fences and walls Dwarf retaining walls surrounding hazards such as drainage access manholes and communication cabinets. Permanent or expected water hazard with depth of water 0.6 m or more, such as a river, reservoir, stilling pond or lake or other hazard which, if entered, could cause harm to the vehicle occupants. A tree or trees having, or expected to have, trunk girths of 250 mm or more (measured at a height of 0.3m above ground level) at maturity Non-motorised User (NMU) subway entrance or agricultural underbridge passing under the highway. A canal or separate road or carriageway. The above will be re-evaluated at preliminary design stage. Typical layouts of safety barrier systems are shown on Drg No TH/SBCC/230/HIG/117 & /118.

4.12.3 Vehicle parapets requiring RRS protection Where a vehicle parapet is required on structures, a safety barrier must be provided to prevent direct impact with each approach end of the vehicle parapet. At each approach end of the vehicle parapet, the safety barrier must be full height for at least the minimum length in advance for the Containment Level of the safety barrier stated in TD19 Table 3-1 and must continue the line of the traffic face of the vehicle parapet. The minimum length may include the length of any transition between the parapet and safety barrier. Where traffic can travel in both directions, either under normal conditions or under temporary traffic management, a safety barrier must be provided at each end of the parapet. 4.12.4 Containment levels at vehicle parapets Containment Levels on roads with a speed limit of less than 50 mph: Normal Containment Level = N1 Normal Containment Level = N2 Higher Containment Level = H2 Very High Containment Level = H4a

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The lowest Containment Levels given above must be provided on road bridges and structures and on bridges and structures over, or adjacent to, roads unless it is assessed that a higher containment level must be provided.

4.12.5 Minimum Lengths of RRS The minimum RRS Length of Need is outlined in TD19 Table 3-1 (summarised below) and Figure 3-5

TABLE 4-3 Minimum Full Height Safety Barrier Length of Need

Safety Barrier Containment Level Minimum “full height” lengths of safety barrier

Containment Level Category In advance of hazard Beyond hazard Normal Containment Level N1 or N2 30m 7.5m Higher Containment Level H1 or H2 30m 10.5m

Very High Containment Level H4a 45m 18m

If the Length of Need determined using the RRRAP is less than the minimum length of “full height” safety barrier in advance, then the minimum length must be provided. In addition, at least the corresponding minimum length of “full height” safety barrier beyond the single hazard, or group thereof, given in Table 3-1 must also be provided

4.12.6 Locations requiring safety barrier The following locations are likely to require protection with safety barrier, subject to more detailed design and a RRRAP assessment:

approach and departure for field drainage channels approach and departure for Liden Brook structure including parapet and flood risk zone area approach and departure for Wanborough Road overbridge including parapet. Embankment height will need to be considered approach and departure for Wanborough Road underpass

4.13 Road Safety Audit A Stage 1 Road Safety Audit (HD19) was not specifically undertaken for the feasibility study, but the concepts of safety in design were adhered to in development of the study.

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SECTION 5 5 Structures

5.1 Existing structures affected Due to a period of inclement weather at the time of writing the report, it was unable to undertake a full walkover survey of the site to determine the number of existing structures. Assessment of the existing mapping data has indicated that there are a number of small footbridges and access points over field drains, but the majority of these lie away from the corridor under consideration. 5.2 Proposed structures The following structures are required:

TABLE 5-1 Proposed structures summary

Chainage / Approximate Reference Crossing Requirement Structure Type Comments Location Co-ordinates Safeguarded route of future WBCT canal 419750, No structure to be 1 Ch 325 Wilts & Berks Canal Refer to Drg Nos 182940 provided TH/SBCC/230/HIG/110 and /120 Safeguarded route of future WBCT canal 419745, No structure to be Wilts & Berks Canal 2 Ch 690 183290 provided Refer to Drg Nos TH/SBCC/230/HIG/110 and /120 Pre-cast concrete culvert 419590, units with in-situ Drainage channel 3 Ch 1000 183550 reinforced concrete Field drain wingwalls Environment Agency In-situ concrete deck and Main River 419570, pre-cast concrete beam Liden Brook crossing 4 Ch 1075 183630 superstructure Refer to Drg Nos supported on piled TH/SBCC/230/HIG/112 abutments and /122, /DRA/201-203 Pre-cast concrete culvert 419580, units with in-situ Drainage channel Field drain 5 Ch 1290 183840 reinforced concrete wingwalls

Bridge option for In-situ concrete deck and crossing Wanborough pre-cast concrete beam Ch 2280 Road 419940, superstructure 6 Wanborough Wanborough Road 184730 supported bank seats on Refer to Drg Nos Road top of reinforce earth TH/SBCC/230/HIG/118, abutments. /125, /143 and /DRA/202

Ch 2280 419940, 7 Wanborough Road In-situ reinforced Underpass option for Wanborough 184730 concrete box unit with crossing Wanborough

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TABLE 5-1 Proposed structures summary

Chainage / Approximate Reference Crossing Requirement Structure Type Comments Location Co-ordinates Road associated in-situ Road reinforced concrete 6% grade used to reduce wingwalls tunnel portal length Refer to Drg Nos TH/SBCC/230/HIG/117, /126, /142 & /DRA/203

5.2.1 Wilts & Berks Canal structures (Ref 1 & 2) The canal structures will not be constructed as part of the EVSCR, but the corridor will be safeguarded. Some local raising of new road sections will be done to assist in future canal construction works. Works to the existing road sections on Wanborough Road would need to be undertaken by the WBCT. The levels of an overbridge on Wanborough Road could be raised to accommodate this change in profile but at present they are based on clearance to the existing carriageway rather than any future canal levels. The costs and details above are for information only and should not be used for the basis of design and costing of future canal works. This will be the responsibility of the Wilts & Berks Canal Trust and their consultants. Typical location of the canal crossing points are shown on Drg Nos TH/SBCC/230/HIG/110, /111, /114, /117, /118, /120, /121 and /124 - /126 Indicative assessment of the requirement for the canal crossing structures are in-situ reinforced concrete box unit with associated in-situ reinforced concrete wingwalls supporting the highway embankment on the approach to the structure. The cross section of the structure would provide: 3.5m wide shared space footway; 2.7m wide by 2.0m deep waterway channel; 0.5m wide wildlife shelf; and 2.7m Vertical clearance above the waterway.

Estimated cost: - £262,000 per structure (The estimated cost is for the structure only, constructed as part of a new highways scheme and excludes any cladding requirements and the cost of any piling needed to support the box should the existing ground conditions be insufficient to allow direct bearing).

5.2.2 Liden Brook river structure (Ref 4) The proposed structure for the river crossing is an in-situ concrete deck and pre-cast concrete beam superstructure supported on piled abutments. In-situ reinforced concrete wingwalls would be required to support the highway embankment on the approach to the structure. The cross section of the structure would support the following: Assumed span: 15.5m wide 7.3m wide carriageway; 2nr. 3m wide footways; and 2nr. 0.5m wide parapet edge beams.

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Estimated cost: - £517,000 per structure (The estimated cost is for the structure only, constructed as part of a new highways scheme and excludes any river works). Further details of the river crossing are shown on Drg Nos TH/SBCC/230/HIG/112 and /122. The construction would be similar to that of the Wanborough Road overbridge on Drg No TH/SBCC/230/HIG/143. A typical example of this type of structure is located at Commonhead roundabout and shown in Photo 41 5.2.3 Wanborough Road overbridge (Ref 6) – Option A3 The proposed structure for the road bridge over Wanborough Road under Option A3 is an in-situ reinforced concrete box unit with associated in-situ reinforced concrete wingwalls supporting the highway embankment on the approach to the structure. Given the gradient limits on the highway alignment the wingwalls for this structure would be at least 120m long on both approaches. The cross section of the structure would support the following: Assumed span: 15.5m wide 7.3m wide carriageway; 2nr. 3m wide footways; and 2nr. 0.5m wide parapet edge beams.

Estimated cost: - £517,000 per structure (The estimated cost is for the structure only, constructed as part of a new highways scheme and excludes traffic management and interfaces with the existing road that may increase construction costs). Further details of the overbridge at Wanborough Road are shown on Drg Nos TH/SBCC/230/HIG/118, /125 and /143. Details of the height of the overbridge and embankment in relation to the surrounding areas is shown on Drg No TH/SBCC/230/HIG/119. A typical example of this structure is located at Commonhead roundabout and shown in Photographs 41 and 42. 5.2.4 Wanborough Road underpass (Ref 7) – Option A4 The proposed underpass structure for the Wanborough Road Option A4 is an in-situ reinforced concrete box unit with associated in-situ reinforced concrete wingwalls supporting the highway embankment on the approach to the structure. Given the gradient limits on the highway alignment the wingwalls for this structure would be at least 120m long on both approaches. The cross section of the structure would provide: 6.1m wide carriageway; 2nr. 1m wide hard strips; 1nr. 1m wide verge and 1nr. 3m wide footway (0.5m offset from the kerb line to the face of the pedestrian guardrail and a minimum footway width of 2m)

The structure would support: 7.3m wide carriageway; 2nr. 2.5m wide footways; and 2nr. 0.5m wide parapet edge beams.

Estimated cost: - £683,000 per structure

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A temporary diversion road would need to be constructed to keep Wanborough Road open during the works. This would be built to the south-west side of Wanborough Road and be in the region of 300m long to go around the excavation. This would avoid traffic being diverted over the intermediate gas pressure main and provide more clearance around Wanborough House. To reduce the diversion road width, temporary traffic signals would be used to permit one way traffic flow and access into the works area. (The estimated cost is for the structure only, constructed as part of a new highways scheme and excludes, cladding, piling (should ground conditions dictate that this is required), traffic management and interfaces with the existing road that may increase construction costs). Further details of the underpass at Wanborough Road are shown on Drg Nos TH/SBCC/230/HIG/117, /126, and /141 - /143. A typical example of this structure is located at Blunsdon Hill, Swindon and shown in Photographs 43 and 44. 5.2.5 Drainage Channel Crossing (Ref 3 & 5) The proposed structures for crossing the drainage channels are pre-cast concrete culvert units with in-situ reinforced concrete wingwalls to support the highway embankment on the approach to the structure. The cross section of the structure would support the following: Assumed width: 15.0m wide 7.3m wide carriageway; 2nr. 3m wide footways; 2nr. 0.5m wide parapet edge beams; and Internal dimensions – 2.1m by 1.5m (South) and 2.7m by 1.8m (North). Estimated cost: - £45,000 per structure (The estimated cost is for the structure only, constructed as part of a new highways scheme and excludes any river works).

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6.1 Flood risk assessment 6.1.1 Introduction This section provides a Flood Risk Assessment (FRA) in accordance with the National Planning Policy Framework (NPPF) 2012, based on the key elements of Planning Policy Statement 25 – Development and Flood Risk (PPS25), and gives due consideration to local policies. Flood risk assessments should be carried out to the appropriate degree at all levels of the planning process, to assess the risks of all forms of flooding to and from the development, taking climate change into account and to substantiate the application of the NPPF sequential test approach.

CIRIA C624 provides guidance on the implementation and good practice in assessing flood risks through the development process; the aim of the document is to promote developments that are sustainable with regard to flood risk. The document recommends that a FRA should be undertaken in phases and promotes three levels of assessment: Level 1 FRA (Screening study): Level 2 (Scoping Study): Level 3 (Detailed Study): This report forms the Level 1 FRA (Screening Study) which provides a general indication of the potential flood risk to the site and identifies whether there are any flooding or surface water management issues that may warrant further consideration or may affect the feasibility of a development. The study has referenced readily available information, including the SFRA, SWMP, Environmental Agency Flood Map and Standing Advice. The FRA only relates to the Eastern Village Southern Connector Road. 6.1.2 Eastern Village Southern Connector Road The proposed Eastern Villages Southern Connector Road (EVSCR) will provide a link between the new Eastern Villages development and Commonhead roundabout to provide connectivity to the Strategic Road Network. The purpose of this link will be to serve local access only and not to provide a strategic route between the A419 to the A420. The route of the EVSCR passes through open farmland and traverse the flood plain of the Liden Brook. 6.1.3 Overview of flood risk to the proposed route The proposed road alignment and the flood zones as published by the Environment Agency is detailed in Figure 6.1

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Proposed EVSCR alignment

Figure 6-1 Environment Agency Flood Zones (risk of flooding from River and Sea)

Figure 6-1 demonstrates that the majority of the route lies within flood zone 1, defined by Planning Policy Statement 25: Development and Flood Risk as having a low annual probability of flooding; however, the route crosses the Liden Brook (a classified Main River) and thus falls within the bounds of Flood Zones 2 and 3, which is described as having a medium and high annual probability of flooding.

Refer to Drg Nos TH/SBCC/230/DRA/200 -/203 for details of drainage proposals and Flood Zones

Table 6-1 below shows the total lengths and proportions of the route within each Environment Agency Flood Zone, and indicates the percentage within each zone.

TABLE 6-1 Environment Agency Flood Zones

Environment Agency Flood Zone Approx Route Length falling within % of total route Flood Zone (km)

Flood Zone 1 (low annual probability) 2.3 89% Flood Zone 2&3 (medium and high annual 0.3 11% probability) Environment Agency: Initial consultation was made with the Environment Agency on the 7th of February 2014, who subsequently confirmed the requirement to produce a Flood Risk Assessment for the scheme. A preliminary opinion request form was submitted to the Environment Agency on 26th of February 2014 in order to assess

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TABLE 6-1 Environment Agency Flood Zones

Environment Agency Flood Zone Approx Route Length falling within % of total route Flood Zone (km) specific requirements for assessment of flood risk and drainage strategy. A response to this request is not yet received at the time of developing the FRA and drainage strategy.

6.2 Methodology The methodology adopted in the flood risk assessment comprises:

A review of associated policy documentation. A desk study review of the current site conditions. Identification of potential sources of flooding. Preliminary calculations to substantiate the current and permitted surface water run-off rates, including an assessment of attenuation volumes necessary to control the rate of run-off as a result development. Identification of applicable sustainable urban drainage systems (SUDS). Recommendations & conclusions

6.2.1 Policy review 6.2.1.1 National Planning Policy Framework The National Planning Policy Framework (NPPF) published in March 2012 sets out the Government’s planning policies for England and how these are to be applied, with an aim towards sustainable development and flood risk mitigation. The NPPF uses a risk based approach to identify suitable locations for development and to aid decisions on development control through a sequential test. The NPPF uses three flood zones to assist in applying sequential tests in flood sensitive locations. The flood zones provide an indication of the likelihood of flooding and predicted extent of the natural flood plain and extreme flood events. The NPPF also categorises the vulnerability of each type of development to define the most suitable uses of land within each flood zone. The NPPF defines the flood risk for each of the flood zones and includes recommendation to reduce the overall level of flood risk as follows: Flood Zone 1 is defined as having a low probability of fluvial flooding (<0.1% or 1 in 1000 year annual probability), and is considered suitable for all forms of development. Developments within Flood Zone 1 should also consider vulnerability to flooding from other sources, and the effect of the development on flooding offsite. Opportunities to reduce the overall level of flood risk in the area and beyond should be sought in the development through the use of sustainable drainage systems (SUDS). Flood Zone 2 is defined as having a medium probability of fluvial flooding(between 1% to 0.1% or 1 in 100 to 1 in 1000 year annual probability), and is considered suitable for all but the most vulnerable developments, such as hospitals. As with Flood Zone 1, vulnerability to other sources of flooding should be considered, and opportunities to reduce overall flood risk should be sought. Flood Zone 3 is defined as having a high probability of fluvial flooding (>1% or 1 in 100 year annual probability), and is considered suitable only for water-compatible and less vulnerable developments, including essential infrastructure

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 6-3 SECTION 6 6 FLOOD RISK ASSESSMENT AND DRAINAGE STRATEGY 6.2.1.2 Flood Risk Vulnerability The review of the flood risk vulnerability classification provided within “Table 2: Flood Risk Vulnerability” of Technical Guidance to NPPF, indicated the wider development related to the Eastern Villages is classified as “Essential Infrastructure” type of development. Referring to the “Table 3: Flood Risk Vulnerability and Flood Zone Compability”, this type of development is permitted within zones 1 & 2, but requires an Exception Test for the development to occur under Zone 3. For the Exception Test to be passed, according to NPPF the proposed development has to comply with the following: Demonstrate that the development provides wider sustainability benefits to the community which outweigh the flood risk, informed by a SFRA where one has been prepared; and A site-specific FRA must demonstrate that the development will be safe for its lifetime, taking account of the vulnerability of its users, without increasing flood risk elsewhere and, where possible, will reduce food risk overall.

6.2.1.3 Climate Change The NPPF states that the effects of climate change need to be considered as part of any new development. In general climate change is expected to result in an increase in rainfall intensity, higher peak river flows and a rise in net sea levels. Table 5 of the NPPF technical guidance states that an additional 30% for peak rainfall intensity should be included for a development with a design life of 100 years. The EVSCR is considered as a new development and thus 30% climate change will be included in the hydraulic design.

It should be noted that within Design Manual for Roads and Bridges, Volume 4, Section 2, Part 3, Surface and Sub-Surface Drainage Systems for Highways (HD 33/06) (The Highways Agency et al, 2006) it is stipulated that the rainfall intensity is to be increased by 20%; however as the route of the EVCR lies within designated flood plain it is proposed to apply the criteria as stipulated within the NPPF.

6.2.1.4 DEFRA/EA Preliminary Rainfall Runoff Management for Developments (Flood Risk User Guide) The approach set out in DEFRA Flood Risk User Guide has been used to estimate the design parameters to calculate the permitted discharge rate and associated storage volumes for greenfield sites, where it has been deemed appropriate. It stipulates that the discharge rate from the proposed development should be less than or equivalent to the runoff generated from the existing site in its current state for storm events up to and including those with 1 in 100 year storm return period, plus an allowance for increased rainfall intensity due to climate change. The pre-development and post-development runoff rates along with the storage requirements are further discussed in Section 6.4. 6.2.1.5 Strategic Flood Risk Assessment and Preliminary Flood Risk Assessment A Strategic Flood Risk Assessment (SFRA) was carried out for Swindon Borough Council in August 2008 (Halcrow 2008). The SFRA was produced to identify areas at risk from flooding and act as a guidance document to planners and developers, it highlighted areas where site specific FRA’s would help inform planning process.

A Preliminary Flood Risk Assessment (PFRA) was completed in 2011 and built on the findings from the SFRA. The PFRA identified areas at risk from historic and future surface water, groundwater and watercourse flooding to prioritise areas for further investigation. The SFRA and PFRA have been used as the principle source of data for an assessment of flood risk.

6-4 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 6 6 FLOOD RISK ASSESSMENT AND DRAINAGE STRATEGY 6.2.1.6 Surface Water Management Plan A Surface Water Management Plan (SWMP) was produced in 2011 (Halcrow) and subsequently amended in 2012 (Halcrow) for Swindon Borough Council. Rainfall modelling was performed through ISIS FAST to identify areas at high risk of surface water flooding during a range of events, and to produce hazard maps for extreme rainfall events. The report also identified the impact of the local topography and sewer network interconnectivity on the location and hazards posed by flooding, emphasising the need to consider an integrated approach of flooding. Questionnaires were collated from a number of parish councils in order to generate a historic flood database while producing the SWMP. All such information has been used to review in order to assess the flood risk to the proposed road alignment.

6.2.1.7 Local Flood Risk Management Strategy A draft Local Flood Risk Management strategy has been developed for Swindon in 2013 (Halcrow) in order to address the local flooding issues predominantly caused from surface water, groundwater, streams and ditches. The objective of LFRM is to identify the areas with high flood risk and to develop a strategy for managing the local flooding issues; and this can be achieved through various stakeholders’ engagement and wider community support. As a part of the strategy all flood risk areas have been identified along with potential source of risk. The recommendations provided within LFRM have been reviewed in order to assess the flood risk to the proposed road alignment.

6.2.2 Assessment of flood risk (all sources) 6.2.2.1 Historic flooding incidents A flood incident database collated for Swindon Surface Water Management Plan (SWMP) suggested the flooding has occurred in the vicinity to the proposed road. The residential properties and roads around Moor Leaze had flooded in 2007 and 2008. Flooding is reported to come overland from the direction of the Liden Brook culvert under Pack Hill, and from the A419 toe drain. On review of the Strategic Flood Risk Assessment (SFRA) regular localised flooding is indicated along Wanborough Road. Figure 6.2 below depicts the areas with localised flooding based on SFRA database. Examples of flooding in February 2014 are shown on Photo 8

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Proposed EVSCR alignment

Figure 6.2 SFRA database for localised flooding in vicinity of proposed road alignment

6.2.2.2 Tidal flood risk The proposed EVCR route is not near enough to the coast to be at risk of tidal flooding either directly or indirectly through tide-locking.

6.2.2.3 Reservoir flood risk Reservoir flooding is extremely unlikely to happen. There has been no loss of life in the UK from reservoir flooding since 1925. However, in the unlikely event that a reservoir dam failed, a large volume of water would escape at once and flooding could happen with little or no warning. The Environment Agency Flood Maps associated with the risk of flooding from reservoirs have been reviewed, which suggest the proposed EVSCR route is not near enough to any reservoirs and therefore is no risk of flooding from beach or over- topping of reservoir. Figure 6.3 indicates the extent of flood risk from the Coate Water (identified as nearest reservoir) based on Environment Agency Flood Maps.

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Proposed EVSCR alignment

Figure 6-3 Environment Agency Flood maps (risk of flooding from reservoir) 6.2.2.4 Groundwater flood risk Groundwater flooding occurs when water levels in the ground rise above surface elevations. The SFRA notes that an assessment of risk from groundwater flooding is difficult to undertake due to a lack of groundwater record data, variable geological conditions and a lack of predictive groundwater modelling tools. Neither the SFRA nor the PFRA identified any historical groundwater flooding events at or near the site. Data from the “What’s in your backyard?” published by the Environment Agency indicates that the development site, along with Swindon as a whole, does not lie within a groundwater protection zone. Figure 6.4 shows the groundwater protection zones in relation to Swindon as a whole.

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Figure 6.4 Environment Agency Source Protection Zone (SPZ) The development site does not overlay aquifers, refer to Figure 6.5

Figure 6.5 Environment Agency Aquifer Map

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The proposed development site is not located on a designated Aquifer therefore the risk of groundwater flooding is negligible, however it is recommended to further investigate the groundwater levels to the development site. 6.2.2.5 Surface water flood risk It is believed that prolonged periods of rain may result in to the ground becoming saturated resulting in the pluvial flows and localised ponding. The wider catchment associated to the proposed ECVR development route is identified as open farmland and may have potential to generate localised flooding during the extreme rainfall events. Figure – below depicts the flood risk from the surface water flows to the proposed road alignment.

Figure 6-6 Environment Agency Flood maps (risk of flooding from surface water) A recent walkover survey of the site has highlighted an issue of localised flooding in the area; however it is proposed that the majority of the route to be raised above the natural ground level, to reduce the risk of flooding from this source. The localised catchments draining towards the ECVR, and changes to the runoff rates as a result of the development, will require management through the use of SUDS, details of which are described in the Drainage Strategy, in Section 6.4. Provision of cut-off drains and culvert crossings to the proposed road will need to be considered to restore the pre-development greenfield runoff characteristics.

6.2.2.6 Risk of flooding from sewers Review of the services search at this stage of study indicated there are no surface water sewers or foul sewers exist in the vicinity of the proposed road alignment and as such there is no risk identified from such sources. The drainage at the junction between Pack Hill and Wanborough Road is noted to comprise over the edge drainage and roadside ditches. These areas have experienced historic flooding as detailed in Section 6.2.3. 1 and will need to be addressed through the promotion of a sustainable drainage strategy.

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 6-9 SECTION 6 6 FLOOD RISK ASSESSMENT AND DRAINAGE STRATEGY 6.2.2.7 Fluvial flood risk As discussed in section 6.1.3 the proposed ECVR route was analysed against Environment Agency Flood Maps. The majority of the route is located within the bounds of flood zone 1, however parts of the route pass through Flood Zones 2 and 3 between chainages 0m and 120m, chainages 1000m and 1300m and chainages 2140m and 2540m. Construction of the new road within the flood plain will compromise the natural flood storage, and may have impact on the hydraulic performance of the upstream catchment. It is thus proposed to mitigation such risk by compensating for the loss of flood plain storage and maintain the flows through the provision of flood relief culverts and clear-span bridges where the road crosses the Liden Brook. This is discussed further in Section 6.3.

6.2.2.8 Risk of flooding from other sources – Water mains There is a 600mm ID strategic water main that traverses the proposed highway route and the risk of flooding as a result of a fractured main is believed to be extreme; resulting into localised flooding. However the extent and frequency of burst water mains are subject to the structural form and condition of the pipeline. Furthermore, the majority of the road sections are elevated and therefore the risk may not be realised. Thames Water will stipulate that the depth of cover to the main must not be excessive and an increase in overburden will hinder emergency operations. 6.2.3 Flood Risk Summary From the information discussed in section 6.2.2, it is clear that the scheme will have impact on the existing risk of flooding. As such, flooding issues shall be further investigated. Since this section of the feasibility study acts as a level one flood risk assessment, it can be concluded that a level two flood risk assessment is required, in accordance with CIRIA Report 624: Development and Flood Risk – Guidance for the Construction Industry.

6.3 Compensatory Flood Storage Areas As discussed in Section 6.2.3.7, the proposed highway will result in a loss of floodplain storage. This loss of storage will need to be compensated for by the provision of compensation flood storage. Since the highway elevation and watercourse crossings are to be designed in relation to the 100 year fluvial flood level (Flood Zone 3), plus an allowance to accommodate climate change, it is anticipated that the compensatory flood storage will also be for the 100 year event. The boundaries of Flood Zones 2 and 3 generally follow the existing flood plain routes. Since there are no groundwater issues anticipated at the site, it is proposed to provide additional flood storage volumes by lowering the elevation of the surrounding land within flood zone 3, so that the footprint of the flood zone is not increased post-development. The estimated flood storage volumes have been determined based on the information available to establish the flood water level. The land should be lowered to not less than the top of bank of the Liden Brook, but should still fall towards the brook and not create any unsafe slopes. For further details refer to Drg Nos TH/SBCC/230/DRA/200 - /203. Between chainages 0m and 120m, there will be no reduction of flood storage post-development as the road is to be at grade, and as such it is not proposed to provide addition storage for this section. It is anticipated that this section of road may continue to experience flood risk which need further review subject investigations on the current drainage assets in the vicinity. Between chainages 1000m and 1300m, it is estimated that around 6,000 cubic metres of flood storage will be lost. It is proposed to lower the existing flood plain downstream of this crossing to accommodate an equivalent volume without altering the footprint of the 1 in 100 top water level associated with flood zone 3. It is anticipated that a greater volume may be required subject to the detailed hydraulic modelling and review of the flood water levels.

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Between chainages 2140m and 2540m, there will be a minimal loss of flood storage, and as such a small amount of storage volume will be provided to compensate for this loss. Further investigation and design will need to be carried out to more accurately determine the compensatory flood storage volumes required, as well as the impacts to the watercourse and flood levels due to the development. It is recommended that 2D ISIS – TUFLOW hydraulic modelling is carried out to facilitate this assessment.

6.4 Conceptual drainage strategy 6.4.1 Introduction The drainage strategy has been developed in accordance with the guidance set out in the National Planning Policy Framework (NPPF) and the Design Manual for Roads and Bridges (DMRB), and hence consideration has been given to the management of the surface water discharge from the proposed highway development site. A comparison of pre and post development surface water runoff rates associated with the rural and urban elements of the site has been undertaken to facilitate the design of an outline sustainable urban drainage system, with the intent of reducing the rate of surface water discharge from the site to mimic the existing conditions of greenfield run-off, whilst giving due consideration to climate change. A conceptual drainage design incorporating Sustainable Urban Drainage Systems (SUDS) has been developed that is considered to be sympathetic with the environment in which the EVSCR is to be constructed. 6.4.2 Design Assumptions The following design assumptions were considered during the initial design phase: The entire route is located within SOIL type 4, as per the Wallingford Winter Rainfall Acceptance Potential (WRAP) Maps. This would suggest that the existing ground conditions offer little permeability, which agrees with the existing geotechnical information for the area (Kimmeridge Clay). Overland flows from existing greenfield areas adjacent to the proposed highway have been assessed based on available LiDAR data. Toe drains are to be provided at the bottom of all embankments and cuttings, with the run-off from these to be directed to the proposed drainage network. The proposed cut-off drains will divert existing pluvial flows from adjacent greenfield areas towards their existing destination watercourse wherever possible, to limit the impact on the proposed drainage system and to mitigate ponding. All surface water discharge will be to a watercourse (Liden Brook – Main River). Since the entire route is to be constructed on existing open farm land, the post-development run-off should be limited to greenfield run-off rates. A degree of betterment will be achieved over the existing arrangement due to the inclusion of an allowance for climate change in the post development run-off calculation. This will offer a slight reduction in flood risk over the current conditions. The Wilts & Berks Canal route for the East Swindon restoration has been safeguarded in its current alignment in the Swindon Borough Council Local Plan. A start date for canal is not confirmed at this stage but it is anticipated that the Eastern Villages will progress prior to the canal construction. For the purposes of this section, the canal has been ignored. Vertical alignment, including highpoint at chainage 1950m assumed to be correct. There is scope to reduce the amount of fill subject to a review of the highway geometry and a geotechnical assessment.

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Vertical alignment at chainage 850m assumed to be correct. There may be a requirement to increase the highway level here to reduce flood risk. Attenuation facilities have been located outside of Flood Zone 3 to ensure the integrity of the flood plain and associated watercourses. Control structures to limit post-development flows to existing greenfield rates for 1 in 1, 1 in 30 and 1 in 100 year storm events, plus an allowance for climate change. The collection of surface water flows from the carriageway is to be in accordance with the details contained in Highway Agency’s Design Manual for Roads and Bridges (DMRB) documentation. It is proposed to use a positive gravity drainage system using kerbs and gullies. During further design it may be deemed efficient to include linear drainage systems along certain sections of the route, such as combined kerb drainage and bridge deck drainage units, where slack gradients and/or bridge deck or underpass construction do not permit gully use. Proposed highway low point at chainage 1140m assumed to be retained, though may need to be investigated during subsequently stages of design. Groundwater levels are assumed to be well below ground level. Any existing field drains and ditches will be suitably culverted beneath the proposed carriageway. Compensatory flood storage area has been assumed based on a high level assessment of the proposed highway footprint in Flood Zone 3, with assumed flood water levels.

6.4.3 Existing surface water runoff rates and volumes The existing catchments predominantly comprise open farmland. The design of the surface water drainage system in these areas is thus required to give due consideration to the NPPF and criteria contained within the SUDS Manual which state that the post-development flow, including an allowance for climate change, is to be no greater than the existing greenfield discharge rate for all storms . The SUDS Manual recommends the use of the IH Report 124 to derive peak flows and volumes for greenfield sites of less than 200ha and the Flood Estimation Handbook (FEH) for areas larger than 200ha. Since all of the catchments are less than 200ha in area, the IH Report 124 method has been used for greenfield calculations. 6.4.3.1 Existing surface water runoff rates Greenfield flow rates have thus been calculated using the methodology set out in the IH Report 124 based on an equation for the mean annual flood (QBAR). The equation for the mean annual flood, as included within the DEFRA Flood Risk User Guide, is:

Where:

QBAR = mean annual flood in m³/s. AREA = site area in km². SAAR = Standard Annual Average Rainfall from Wallingford Maps in HR Wallingford (1981). SOIL = Soil index of the catchment from HR Wallingford (1981). Soil classes 1 to 5 have Soil Index values of 0.15, 0.3, 0.4, 0.45 and 0.5 respectively.

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The Wallingford Winter Rainfall Acceptance Potential (WRAP) map suggests the strata comprise SOIL Type 4 for the whole scheme. The catchment descriptors from the Wallingford Maps (HR Wallingford, 1981) provide a SAAR of 700mm and SOIL of 0.45. The IH Report methodology calculates the peak discharge rates based using a 50ha area which is then used to linearly interpolate the flow rate for the actual site area. The calculated peak flows per hectare associated with the greenfield site catchments are given in Table 6-2 below.

Table 6-2 Greenfield site runoff for all catchments

Return Period (years) Greenfield Site Runoff for all catchments (l/s/ha)

QBAR 4.39

1:1 3.74

1:30 9.92

1:100 13.98

6.4.3.2 Existing surface water runoff volumes During high return period storm events, it is necessary to control the total volumes being discharged to a watercourse. DEFRA/EA (2005) requires that a certain volume, typically the volume resulting from a 6 hour, 100 year event, is controlled to the equivalent greenfield volume. DEFRA/EA (2005) states that this should be controlled using the following methods in order or preference: The additional volume should be infiltrated to the ground The additional volume should be discharged to the watercourse at below 2/l/s/ha Since the native soil offers very little permeability, it would be impractical to infiltrate to the ground, therefore the long term storage volume should be controlled by discharging it at below 2/l/s/ha. It should be noted however that DEFRA & EA (2005) suggests that a practicable minimum limit of 5 l/s should be applied to the discharge rate to keep the risk of blockage to an acceptable level. Where the greenfield rate for the catchment is calculated as below 5 l/s, this practicable minimum limit has been applied. Long Term Storage Volumes should be calculated during the next design phase using the approach outlined in CIRIA (2007), using the following formula: PIMP PIMP Vol RD.A.10 0.8 .SPR , where: 100 100 RD = Rainfall depth for 100 year, 6 hour event (calculated as 85.3mm using HR Wallingford (1981)). A = Total catchment area (ha). PIMP = Percentage impermeability of the catchment. SPR = “SPR” index for the FSR SOIL type (0.45 used throughout).

6.4.4 Proposed drainage strategy The surface water drainage strategy for the EVSCR has been developed in accordance with the NPPF, DEFRA & EA (2005). A sustainable surface water drainage strategy has been promoted where viable, giving due consideration to the nature of the development site, extent of flood plain and proposed highway vertical alignment.

6.4.4.1 Proposed Drainage Catchments The route of the EVSCR has been assessed in terms of drainage catchments based on the vertical alignment of the proposed highway.

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Suitable discharge points have been determined for each catchment or sub-catchment; where viable surface water is discharged directly to watercourses located in close proximity to the network’s attenuation facility in accordance with guidance within the NPPF.

The selection of an outfall has been based on the following order of preference: Infiltration. Discharge to watercourse. Discharge to existing surface water sewers.

Since infiltration drainage is not a viable option due to impermeable native soil types, it is therefore proposed that the attenuation facilities discharge to the Liden Brook watercourse, as this is the next preference for surface water discharge. Below is a summary of the catchments proposed for Option 1 of the EVSCR (Wanborough road crossing at grade). Please refer to drawing THSBCC230/DRA/201 for a general arrangement of Option 1.

Catchment A Length 240m Start Chainage 0m End Chainage 240m Existing ground Greenfield Flood Zone 3 Proposed 250m3 to limit discharge to greenfield rates of: attenuation 1 yr: 5 l/s (using practicable minimum limit as calculations give 1.7 l/s) 30 yr: 5 l/s (using practicable minimum limit as calculations give 3.7 l/s) 100 yr: 5 l/s (using practicable minimum limit as calculations give 4.9 l/s) Attenuation On-line storage (tank sewer) likely, due to space restrictions and location of Flood Device Zone 3. Discharge Point New headwall on Liden Brook Comments Cut-off drain to divert overland flows from natural catchments to the Liden Brook. No additional treatment of run-off proposed. Catchment Area 0.44ha (highway and embankment)

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Catchment B Length 430m Start Chainage 240m End Chainage 670m Existing ground Greenfield Flood Zone 1 Proposed 450m3 to limit discharge to greenfield rates of: attenuation 1 yr: 5 l/s (using practicable minimum limit as calculations give 3.2 l/s) 30 yr: 8.5 l/s 100 yr: 11.9 l/s Attenuation Device Suitably sized swale with check dams and control device(s), to be combined with (Swale 1) Catchment C swale. Swale to terminate at the boundary of Flood Zone 3. Discharge Point New headwall on Liden Brook for combined swale for catchments B and C. Comments Cut-off drain to divert overland flows from natural catchments to the Liden Brook. Catchment Area 0.89ha (highway and embankment)

Catchment C Length 375m Start Chainage 670m End Chainage 1045m Existing ground Greenfield Flood Zone 3 Proposed 650m3 to limit discharge to greenfield rates of: attenuation 1 yr: 5 l/s (using practicable minimum limit as calculations give 4.6 l/s) 30 yr: 12.2 l/s 100 yr: 17.2 l/s Attenuation Device Suitably sized swale with check dams and control device(s), to be combined with (Swale 1) Catchment B swale. Swale to terminate at the boundary of Flood Zone 3. Discharge Point New headwall on Liden Brook for combined swale for catchments B and C. Comments Cut-off drain to divert overland flows from natural catchments to the Liden Brook. Catchment Area 1.18ha (highway and embankment)

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Catchment D Length 905m Start Chainage 1045m End Chainage 1950m Existing ground Greenfield Flood Zone 3 Proposed 1750m3 to limit discharge to greenfield rates of: attenuation 1 yr: 13.1 l/s 30 yr: 34.8 l/s 100 yr: 49.0 l/s Attenuation Device Suitably sized swale with check dams and control device(s). (Swale 2) Discharge Point New headwall on Liden Brook. Further investigation required as discharge point from swale is approximately 400m from Liden Brook. May require submerged outfall. Comments Cut-off drain, potentially with culverts beneath the embankment, to divert overland flows from natural catchments to the Liden Brook. Catchment Area 3.22ha (highway and embankment)

Catchment E Length 676m Start Chainage 1950m End Chainage 2626m Existing ground Greenfield Flood Zone 3 Proposed 1100m3 to limit discharge to greenfield rates of: attenuation 1 yr: 8.2 l/s 30 yr: 21.9 l/s 100 yr: 30.8 l/s Attenuation Device Suitably sized swale with check dams and control device(s) to run along (Swale 3) Wanborough Road towards Liden Brook. Discharge Point New headwall on Liden Brook. Comments Cut-off drain, potentially with culverts beneath the embankment, to divert overland flows from natural catchments to the Liden Brook. Further investigation required as discharge point from drainage network to swale is approximately 300m from Liden Brook. May require submerged outfall or potentially pump station as road is at grade at the junction with Wanborough Road. Catchment Area 2.19ha (highway and embankment)

The attenuation measures shown on the Drawing THSBCC230/DRA/201 indicates the maximum volume of 1435m3 (Swale 1) can be achieved for Catchment B & C. Similarly attenuation measures for catchment D and catchment E can offer maximum volume of 1980 m3 (Swale 2) and 1200m3 (Swale 3) respectively. It is noted that the storage volumes proposed above have considered rainfall event of 1 in 100 year plus 30% climate change effect and controlling the post-development runoff to the greenfield site conditions before

6-16 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 6 6 FLOOD RISK ASSESSMENT AND DRAINAGE STRATEGY discharging into Liden Brook. Below is a summary of the catchments proposed for Option 2 of the EVSCR (Wanborough crossing – overbridge). Please refer to drawing THSBCC230/DRA/202 for a general arrangement of Option 2.

Catchments A to D are as per Option 1.

Catchment E Length 350m Start Chainage 1950m End Chainage 2300m Existing ground Greenfield Flood Zone 1 Proposed 1050m3 to limit discharge to greenfield rates of: attenuation 1 yr: 7.79 l/s 30 yr: 20.9 l/s 100 yr: 29.4 l/s Attenuation Suitably sized swale with check dams and control device(s) to run along Device Wanborough Road towards Liden Brook. Discharge Point New headwall on Liden Brook. Comments Cut-off drain, potentially with culverts beneath the embankment, to divert overland flows from natural catchments to the Liden Brook. Catchment 2.10ha (highway and embankment) Area

Catchment F Length 326m Start Chainage 2300m End Chainage 2626m Existing ground Greenfield Flood Zone 3 Proposed 1200m3 to limit discharge to greenfield rates of: attenuation 1 yr: 8.9 l/s 30 yr: 23.9 l/s 100 yr: 33.6 l/s Attenuation On-line storage (tank sewer) likely, due to space restrictions and location of Device catchment low point in flood zone 3. Discharge Point New headwall on Liden Brook. Comments Cut-off drain, potentially with culverts beneath the embankment, to divert overland flows from natural catchments to the Liden Brook. No additional treatment of run-off proposed. Catchment 2.40ha (highway and embankment) Area

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Below is a summary of the catchments proposed for Option 3 of the EVSCR (Wanborough road crossing – tunnel). Please refer to drawing THSBCC230/DRA/203 for a general arrangement of option 3. Catchments A to D are as per Option 1.

Catchment E Length 676m Start Chainage 1950m End Chainage 2626m Existing ground Greenfield Flood Zone 3 Proposed 1750m3 to limit discharge to greenfield rates of: attenuation 1 yr: 13.1 l/s 30 yr: 34.8 l/s 100 yr: 49.0 l/s Attenuation Suitably sized swale with check dams and control device(s) to run along Device Wanborough Road towards Liden Brook. Pumping station will be required at the low point of the catchment as the catchment is in cut, which will pump to the swale, which in turn will have a control device at their downstream end to control the discharge into the Liden Brook. Discharge Point New headwall on Liden Brook. Comments Combine outfall to Longmoor Brook with realigned existing Park & Ride drainage outfall. Run-off from new development should be kept separate from the existing Ashton Vale Park and Ride drainage system. Catchment 3.50ha (highway, embankment and cutting) Area

6.4.5 Sustainable urban drainage options Planning Policy Statement 1 “Delivering Sustainable Development” (Office of the Deputy Prime Minister, 2005) and NPPF (2012) require that local planning authorities (LPA’s) promote Sustainable Drainage Systems (SUDS) and as such, LPA’s should ensure that policies encourage sustainable drainage practices in their Local Development Documents. SUDS is a term used to describe the various approaches that can be used to manage surface water drainage in a way that mimics the natural environment. SUDS objectives are to minimise the impacts from the development on the quantity and quality of the run-off, and maximise amenity and biodiversity opportunities. The management of rainfall (surface water) is considered an essential element for reducing future flood risk to both the site and its surroundings. The Environment Agency expects attenuation of run-off from any development site to promote discharge at greenfield rates, and SUDS provide a mechanism for achieving this. The use of SUDS to support the EVSCR have been considered to aid in the conveyance of surface water, attenuation and discharge. Limitations in available space adjacent to carriageways due to highway boundaries or surrounding future development, as well as the footprint of Flood Zone 3, restrict the implementation of many SUDS features.

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Furthermore, the permeability of the ground is found to be negligible, and as such infiltration SUDS are deemed inappropriate. Following a high level review of the proposed EVSCR scheme, available space and the vertical alignment of the highway, it is determined that the applicable SUDS measures for the collection, conveyance and attenuation of anticipated surface water flows are swales and oversized pipes, each with downstream flow control devices.

6.4.5.1 Swales Swales are vegetated depressions of a linear nature the can be used for the conveyance, treatment and attenuation of surface water. Due to the impermeable nature of the existing ground at this site, it would not be practical to design swales to be capable of infiltration. In comparison to other forms of SUDS, swales do not require a large area of land take and follow the alignment of the proposed highway. Typically swales are used as an over-the-edge drainage feature, however the EVSCR will utilise a kerb and gully collection system. Since the majority of the highway will be on embankment, it is proposed to install swales at the bottom of highway embankments with gullies discharging directly into them. Swales may need to be offset from the toe of the highway embankment to ensure there are no slope stability issues. Swales provide removal of pollutants at a low capital cost, with a reduction of run-off rates. Typical maintenance requirements for Swales include: Litter and debris removal (monthly, or as required) Grass cutting to retain grass height within specified design range (monthly during growing season, or as required) Manage other vegetation and remove nuisance plants (monthly at start, then as required) Occasional maintenance will include: Check for poor vegetation growth due to lack of sunlight or dropping of leaf litter, and cut back adjacent vegetation where possible (annually) Re-seed areas of poor vegetation growth. Alter plant types to better suit conditions, if required (annually) Remedial actions will include: Repair erosion or other damage by re-turfing or reseeding (as required) Re-level uneven surfaces and reinstate design levels (as required) Remove build-up of sediment on upstream gravel trench, flow spreader or at top of filter strip (as required) Remove and dispose of oils or petrol residues using safe standard practices (as required) Monitoring activities will include: Inspect inlets, outlets and overflows for blockages, and clear if required (monthly) Inspect inlets and facility surface for silt accumulation. Establish appropriate silt removal frequencies (half yearly) Locations of swales proposed for the EVSCR and typical cross sections are shown on Drg Nos TH/SBCC/230/HIG/140 and TH/SBCC/230/DRA/201 – 203. 6.4.5.2 Tank Sewers Oversized pipes can be implemented as on-line or off-line storage. These systems allow for potentially high storage volumes dependent upon the restrictions of the site and restrictions in the hydraulic performance of

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 6-19 SECTION 6 6 FLOOD RISK ASSESSMENT AND DRAINAGE STRATEGY the overall drainage network. These systems do not provide water quality treatment. In order to limit maintenance requirements, a catchpit should be located upstream of the tank sewer to remove sediment from the runoff before it is able to settle inside the tank sewer itself. It is proposed to use a tank sewers only for catchments where there is no available space for any other means of attenuation storage due to the location of Flood Zone 3. The discharge from such storage could lead to the pumping requirements subject to further investigation and review of the levels into Liden Brook. Efforts will be made to avoid such requirements and alternative options would be considered. Since tank sewers offer little to no water treatment, it may be deemed necessary to provide a proprietary prefabricated surface water treatment unit downstream of the tank sewers, to treat the run-off prior to it discharging to the watercourse. The requirement for future treatment will be subject to discussions with the EA. EA (2006) determines that underground attenuation tanks and tank sewers are the least sustainable SUDS measure for implementation into sites. The use of these SUDS feature should be deemed as a last resort where all other forms of SUDS are proved to be unsuited to the site conditions. Typical maintenance requirements for tank sewers include: Inspect and identify any areas that are not operating correctly. If required, take remedial action (monthly for 3 months, then six monthly) Debris removal from catchment surface (monthly) Remove sediment from pre-treatment structures (annually, or as required) Remedial actions will include: Repair/rehabilitation of inlets, outlet, overflows and vents (as required) Monitoring activities will include: Inspect/check all inlets, outlets, vents and overflows to ensure that they are in good condition and operating as designed (annually and after large storms)

6.4.6 Design Exceedance When designing for SUDS it is necessary to be aware that it is not possible to accommodate all conceivable rainstorm conditions. For this reason consideration needs to be given to flow paths once the SUDS system is operating beyond its designed capacity. This is termed “designing for runoff exceedance”. The SUDS features should therefore be associated with designated pathways for exceedance flow, linking them to watercourses. Due to the nature of the scheme and the proximity of the watercourse, every catchment would discharge to the Liden Brook in instances of design exceedance. 6.4.7 SUDS management train In order to protect the receiving watercourse or sewer from pollution, adequate treatment (or other protection) must be provided within the surface water drainage system. The aim of the detailed drainage design shall be to provide adequate treatment within SUDS components where practicable; however, as is normal practice, the use of sediment traps may be required in some areas to ensure compliance with Water Framework Directives. Many SUDS components provide some level of treatment and these can be used in combination to give the required level of protection. Swales, filter drains and detention basins, as well as providing a degree of storage retention, also provide a level of treatment to the runoff. The grass, over which the water currently flows, provides biological absorption of pollutants. Where it is not possible to achieve such treatment benefits, a provision of prefabricated surface water treatment unit will be considered, to treat the run-off prior to it discharging to the watercourse

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Oil separators may be required to protect the receiving water environment from hydrocarbon pollution in areas where the level of entry of hydrocarbons into the surface water drainage system is potentially high. Should these be found to be required after undertaking a risk assessment, these should be specified in accordance with Pollution Prevention Guidelines 3 (PPG3) – Use and Design of Oil Separators in Surface Water Drainage Systems (EA, 2006).

Catchpits or sediment traps may be required in areas where the level of entry of particulates into the surface water drainage is potentially high. Table 3.3 of CIRIA (2007) suggests an approach for setting the level of treatment that surface water runoff will pass through before being discharged. CIRIA (2007) suggests that one level of treatment is provided for roof areas, two levels of treatment for residential roads, parking areas and commercial zones and three levels of treatment for highways, subject to the sensitivity of the receiving watercourse.

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SECTION 7 7 Geotechnical assessment

7.1 Introduction CH2M HILL was commissioned by Swindon Borough Council (SBC) to undertake a feasibility study of the construction of a new link road on the eastern side of the town of Swindon as part of the Eastern Villages scheme. This geotechnical desk study forms part of the feasibility study for the scheme. The Eastern Villages link road is approximately 2.3km long, and it is proposed to comprise a two lane highway. The route under consideration follows an alignment from the south, at the junction of Pack Hill and The Marsh, running north along the eastern side of the A419 before routing off to the northeast to Wanborough Road, in the vicinity of Poplars Nursery. The approximate National Grid references of the start and end of the proposed main route are: Start: 419570 182789; End: 420060 184865.

Site location

Figure 7-1 Location plan

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 7-1 SECTION 7 7 GEOTECHNICAL ASSESSMENT 7.2 Purpose of the Desk Study This desk study report collects, collates and appraises the available geological and geotechnical information relevant to the proposed investigation area to identify the geotechnical and environmental issues, constraints and opportunities associated with the development of the Eastern Villages link road.

This report seeks to: Ascertain and report upon the land use history of the site Identify and report upon the published geological setting of the site Present the findings of a walkover survey of the site undertaken by CH2M HILL personnel Assess the geotechnical issues, constraints and opportunities attendant with the development of the EVSCR Assesses the potential contaminated land and waste management issues that may constrain the EVSCR Make recommendations for additional works as may be required to reduce or eliminate the geotechnical constraints identified which may include intrusive ground investigation.

7.3 Sources of information The following information has been consulted during the preparation of this report. A full list of references used is given in the References section: Current editions of Ordnance Survey maps (Ref. 1) Unexploded Ordnance Risks Maps (Ref. 2 and Appendix C) British Geological Survey (BGS) 1:63 360 scale solid and drift map and sheet memoirs (Ref. 3) Historic maps from the Landmark® Envirocheck® report (Ref. 4) Environmental issues maps from the Landmark® Envirocheck® report (Ref. 4) Flood maps from the Landmark® Envirocheck® report (Ref. 4) Borehole records obtained from the British Geological Survey (Table 1) Site visit photographs dated 13/02/2014 It was agreed with SBC, that the desk study should be based on the Landmark® Envirocheck® report (Ref 4 - originally purchased for the Swindon Eastern Development Area Canal project in March 2008), as the canal study area was considered to adequately encompass the Eastern Villages link road area. It should therefore be noted that any changes or updates to this information since the report purchase date will not have been identified and taken into account, although it is anticipated that the majority of information will remain unchanged.

7.4 Site location and description Figure 4.1 below shows the proposed site location and route alignment. The study corridor ranges from approximately 200m width (central section) to 550m width (southern and northern sections), and is bounded by: the A419 to the west, Wanborough Road to the north,

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Pack Hill (road) to the south and The Marsh (road), areas of open fields, farm buildings and other properties to the east. The proposed main road alignment is approximately 2.3km in length and is located immediately to the east of the A419 and approximately 4.5km east of the town of Swindon. This road alignment is also indicated to have a spur linking to The Marsh approximately 500m from the southern end. Layout of the EVSCR is shown on Drg Nos TH/SBCC/230/HIG/110 - /118.

Proposed canal route

A419

Proposed road alignment

Water main

The Marsh Liden Brook

Pack Hill

Figure 7-2 Proposed alignment

The site currently comprises an area of relatively low lying open fields and flood plains with predominantly agricultural use. The proposed road alignments cross Liden Brook, a tributary of the River Cole, and also field drains along the proposed route. At both ends of the link, residential properties and farms are located in close proximity to the road alignment. Route also passes next to a farm opposite Wheatstone Road and other spread properties over 200m off the route to the east of the site.

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 7-3 SECTION 7 7 GEOTECHNICAL ASSESSMENT 7.4.1 Plan Alignment The southern extremity of the proposed route links in at the existing junction with Pack Lane and The Marsh. Heading northwards, the road the curves to the east of The Marsh for approximately 250m then crosses over The Marsh in a north-north-westerly direction towards the A419 for 700m. At the crossing with Liden Brook the road gradually curves to the north-north-east and continues in this direction for approximately 1150m to meet the northern crossing point with Wanborough Road. The current route under investigation ends approximately 200m north-east of the Wanborough Road junction/crossing. The alignment also crosses over the route of a proposed future stretch of the Wiltshire and Berkshire Canal at three locations, immediately east and west of The Marsh and north of Wanborough Road. Layout of the EVSCR is shown on Drg Nos TH/SBCC/230/HIG/110 - /118. 7.4.2 Ground Elevation and Vertical Alignment The existing ground level is generally flat through the site. The southern extremity of the link road is at approximately 104m AOD elevation, and gradually decreases to approximately 96m AOD at the northern extremity. For the purposes of this study the following information has been provided by the highway team: Road is assumed to be on embankment, approximately 1 to 4m high, for the majority of the length, The highest sections of embankment will be to form a bridge or culvert across Liden Brook and to raise the road above maximum flood levels where necessary, Embankment side slopes are currently proposed to be shallow, with a 1 in 6 gradient, to merge into surroundings. Various options are currently being considered for the ‘crossing’ with Wanborough Road, as follows: At-grade signalised junction: no significant earthworks required, Overbridge: this option increases the vertical alignment to approximately 102mOD, requiring embankment heights of up to 8m, Tunnel: this option would decrease the vertical alignment to approximately 89mOD (depth of approximately 7m). The at-grade signalised junction is the current preferred option. Vertical alignment details of the different options are shown on Drg Nos TH/SBCC/230/HIG/119, /120 - /126. Typical sections are shown on Drg Nos TH/SBCC/230/HIG/140 - /143.

7.5 Site Background 7.5.1 Site History The history of the site along the proposed route was investigated by reference to historical mapping, provided as part of the Envirocheck® report (Ref. 4). Historical Ordnance Survey maps at scales of 1:10 000, 1:10 560, 1:2 500 1:1 250 were available at discrete publication dates from 1882, 1st edition Ordnance Survey maps, to the most recent editions of the 1:50 000 and 1:25 000 scale maps (Ref. 1). The following is a summary of the findings of the review of the historical mapping data. Land along the proposed route has been predominantly rural and in agricultural use since mapping began in around 1820; Construction of the A419 trunk road was completed along the alignment of a known Roman Road in 1977;

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Development of the residential and commercial area to the west of the A419, at Dorcan, Eldene and Liden, commenced in around 1960 and continues to the present; A prehistoric earthwork is marked in the fields immediately to the south of the proposed road link, between the existing Pack Hill road and the B4192 on all surveys from 1925 to the present. The line of the A419 is known to be a Roman Road and the current Wanborough Road, which is connected to the north end of the road link, runs along the route of a Roman Road (the Ermin Way). A roman settlement is marked at the intersection of the Wanborough Road and the A419.

7.5.2 Unexploded Ordnance Unexploded ordnance (UXO) from the Second World War can present a risk to modern construction activity. Bombs often penetrated the ground by several metres on impact and, if they failed to explode, may continue to exist in a live state. A preliminary assessment of the potential for UXO at the site and its surroundings has been made by reference to the Zetica regional unexploded ordnance risk map, obtained from the Zetica website (Ref 2). A copy of this is presented in Appendix B. This map indicates that the site is within an area of LOW risk of encountering unexploded World War II ordnance. The risk map shows that there are records of 45 No High Explosive but no Anti Personnel or Incendiary bombs have fallen on the Swindon area. In addition, military, utility industrial locations and the mainline railway from London to South Wales, which crosses the site just 1.5km to the north, are shown to have been a strategic target in Swindon area. For this reason, a further investigation of the location of these WWII targets and, if necessary, a site specific UXO desk study is recommended for the site prior to undertaking intrusive ground investigation or construction works.

7.5.3 Walkover Survey At the time of study preparation, wet and flooded conditions at the site did not permit a geotechnical site walkover. Those areas that could be observed from existing roads were inspected by a CH2M HILL Highways Engineer on 13 February 2014. Due to the limited access the Highway Engineer could not identify existing structures and crossings along the proposed alignment, but noted the following points: The conditions observed generally appeared consistent with the available mapping. Standing water was observed in fields and ditches in the area after the prolonged period of wet weather. This suggests that the infiltration potential of the soil may be limited. 7.5.4 Utilities CH2M HILL issued C2 notices to utilities companies in the Swindon and Wanborough area to identify the approximate locations of existing utilities. This information was used at feasibility stage to identify the works required to divert utilities for indicative costing purposes. The following utilities were identified and might affect GI works to be undertaken in the area: Telecommunications overhead and underground cables across the site with reduced headroom. Fibre optic cables alongside Wanborough Road. 600mm water supply main running north-south from Wick Lane to Pack Hill alongside the proposed route.

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11kV high voltage overhead cable routes along the alignment. Two intermediate pressure gas mains present, north of Wanborough Road and west-east across the site. Additionally, a low pressure gas main is located at Wanborough Road. This information should not be regarded as a complete list. Also, prior to any intrusive works, the potential locations for boreholes or trial pits should be checked against the available records. At all proposed borehole locations, hand dug trial pits should be excavated to prove the absence of near surface utilities. Machine excavated trial pits should only be excavated in areas where services are proved unlikely to exist.

7.6 Geology and Ground Investigation Records

7.6.1 Local Geology The regional geology of the proposed route has been established by reference to the British Geological Survey (BGS) 1:63 360 scale map; Sheet 252 – Swindon, Solid and Drift (Ref. 2) and Landmark® Envirocheck® report (Ref. 4). 7.6.1.1 Superficial Deposits Deposits of alluvium are marked on the geological map associated with Liden Brook. The proposed route crosses the strip of alluvium for approximately 1km adjacent to the A419. Deposits of head, a mixed sedimentary deposit formed as the result of mass movement and creep of saturated sediments under periglacial conditions, are identified to the south-east of the site, and although the route does not directly cross any marked deposits of this material, it is possible that it will be encountered in excavations. The Envirocheck® report highlights the presence of a number of recorded landslips located within the head deposits in the order of 1km to 2km to the south-east of the proposed route; these landslips are located exclusively within the head deposits which are confined to the slopes around Liddington and Wanborough. There is no specific indication of Made Ground on the reviewed historical and geological maps. Made Ground may exist locally along the proposed route where material has been moved and tipped as the result of agricultural operations. 7.6.1.2 Solid Geology The solid geology of the route comprises mudstone of the Lower Cretaceous Gault Formation over older mudstone and sandstone of the Upper Jurassic Kimmeridge Clay. The southern 1.5km of the route passes over the Gault Formation, and lies close to this formation’s lower boundary with the unconformable Lower Greensand formation, passing into the Kimmeridge Clay approximately 600m south of the intersection with Wanborough Road. Appendix B shows the geological maps of the area. The Gault Formation is generally described by the BGS as a pale grey to dark grey clay or mudstone which is sandy at the base of the unit. The regional geological structure is of bedding dipping very gently to the southeast. No faulting coincident with the proposed route is marked. 7.6.2 Ground Investigation Records A search was made of the borehole records held by the BGS (see Figure 2 below). This search identified a number of boreholes associated with the A419 Commonhead roundabout scheme. These were reviewed and seven holes, identified in Table 7-1 considered as the most useful due to their closer proximity to the route alignment. Additionally, four boreholes within the Dorcan industrial area to the west of the A419

7-6 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 7 7 GEOTECHNICAL ASSESSMENT were reviewed. These boreholes are in the order of 200 to 500m from the proposed route. From the east side of the site only BH SU28SW14 was available for review and presented illegible information. Refer to Table 7-1.

Figure 7-3 BGS Borehole Records in the area of interest

TABLE 7-1 British Geological Survey Borehole Records

Ground Location / BGS code Easting Northing Final Depth Elevation Geology Water depth Notes (m AOD)

Commonhead roundabout

SU18SE180 419389 182905 4.00 101.67 Stiff Made ground Not given Trial pit was clay to 2mbgl dry and stable overlaying very stiff slightly gravelly weathered clay to base of hole at 4.00m.

SU18SE196 419375 182642 6.35 97.37 Firm Made ground Not given clay to 3mbgl overlaying firm to stiff Gault clay down to depth of 6mbgl

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TABLE 7-1 British Geological Survey Borehole Records

Ground Location / BGS code Easting Northing Final Depth Elevation Geology Water depth Notes (m AOD) and weak weathered sandstone to base of hole

SU18SE197 419435 182849 2.35 99.91 Soft-firm Made 2mbgl ground clay to 1mbgl overlaying weak weathered sandstone to base of hole

SU18SE217 419399 182849 10.55 93.73 Firm clay to 3mbgl Not given overlaying weak to very weak sandstone alternated with firm to stiff clay to base of hole

SU18SE230 419383 183081 4.00 102.26 Stiff cohesive Made Not given ground and clay to base of hole at 4.00m.

SU18SE251 419391 182803 3.90 101.89 Very stiff sandy clay Dry No to base of hole groundwater encountered (20/06/2005)

SU18SE252 419407 183013 4.30 99.91 Firm made ground Dry Trial pit clay to 1.5mbgl terminated on overlaying firm to base of cobble stiff sandy clay down size sandstone to 3.5mbgl and (4mbgl) gravelly sand to base of hole.

Dorcan Industrial Area

SU18SE10 12.19 92.51 Firm-soft sandy clay 1.98mbgl 500m west (Lower Greensand) (01/08) A419 at to 2.6mbgl 10.21mbgl junction overlaying firm to (01/08) between Liden stiff silty Kimmeridge Drive and clay to base of hole 12.04mbgl Eastmere (01/08) (Dorcan 0.91mbgl Industrial (02/08) Estate)

SU18SE12 6.10 99.30 Firm-Gault clay to 3.05mbgl 400m west 2.2mbgl overlaying (30/07) A419 at stiff to very stiff silty 5.64mbgl junction Kimmeridge clay to (30/07) between Liden base of hole Drive and 3.20mbgl Austen (31/07) Crescent 0.61mbgl (Dorcan

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TABLE 7-1 British Geological Survey Borehole Records

Ground Location / BGS code Easting Northing Final Depth Elevation Geology Water depth Notes (m AOD) (02/08) Industrial Estate)

SU18SE63A- 2.00 Not Firm silty clay Dry 100m west G BH1 recorded (Alluvium) to 0.8mbgl A419 overlaying firm to (Skillcentre stiff Kimmeridge clay project) to base of hole Fadaray Park. Hole dry

SU18SE63A- 2.20 Not Firm silty clay Dry 100m west G BH2 recorded (Alluvium) to 1mbgl A419 overlaying firm to (Skillcentre stiff Kimmeridge clay project) to base of hole Fadaray Park. Hole dry. Slight seepage of water at base level after 3hrs.

East of site

SU28SW14 Not Borehole text recorded illegible

The Kimmeridge Clay Formation was encountered during a previous Halcrow, a CH2M HILL company, investigation in an area to the north-west of the site (Ref. 6). During this investigation the formation was found to comprise soft, becoming firm, then stiff with depth, grey, mottled orange brown, slightly sandy clay with some gravel below 4.5m and isolated mudstone bands in the order of 0.2m in thickness. Groundwater monitoring from this investigation indicated that groundwater levels were at or approximately 2.25m below the ground surface. 7.6.3 Coal Mining Activities The Envirocheck® report (Ref 4) notes that area is unlikely to have been affected by coal mining.

7.6.4 Hydrology and Hydrogeology Flood mapping of the area from the Envirocheck® Report indicates that the River Cole tributaries flowing from the south are at risk from flooding events (Appendix A). The proposed route passes through these flood risk areas. A review of Environment Agency flood mapping also indicates that parts of the development lie within medium and high risk flood zones. Envirocheck® report (Ref. 4) also indicates the presence of minor aquifers in the area. The proposed route passes over two aquifers located 100m west of the A419 between Eastmere Road and Wheatstone Road. Groundwater observations and recordings from previous boreholes in the area indicate that there is potential for groundwater levels to be at or within a few metres of the ground surface, although levels recorded were variable.

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7.7 Geotechnical Issues 7.7.1 Scheme Overview The proposed scheme comprises the following elements: New road either at-grade or on low embankments with locally higher embankments in areas with flooding potential, Bridge crossing at existing Liden Brook, comprising in-situ concrete deck and pre-cast concrete beam superstructure supported on piled abutments, Drainage ditch crossings, comprising pre-cast concrete culvert units with reinforced concrete wingwalls to support the highway approach embankment, Crossing/junction at Wanborough Road which may comprise either: o An at-grade junction – Drg Nos TH/SBCC/230/HIG/115 & / 116 o An overbridge - concrete deck and pre-cast concrete beam superstructure supported bank seats on top of reinforced earth abutments – Drg No TH/SBCC/230/HIG/118 o An underpass - reinforced concrete box unit, installed by cut and cover, with associated reinforced concrete wingwalls supporting the highway approach embankment – Drg No TH/SBCC/230/HIG/117 Some local raising of new road sections to assist in future canal construction works at possible crossing points could be incorporated into the design. Initial information from the Highways Team indicates that embankments will have shallow side slopes of 1:6. The source and type of fill proposed for the embankment structures is currently unknown. Typical section details are shown on Drg No TH/SBCC/230/HIG/140 – 143. The published geology indicates that the ground conditions likely to be encountered in excavation along the northern part of the route comprise the Kimmeridge Clay Formation and through the southern part of the route the Lower Cretaceous Gault Formation. Both of the solid geology formations (Kimmeridge and Gault) are predominantly over consolidated stiff clay. Areas of the southern and central sections of the route also pass through deposits of alluvium present along the route of Liden Brook.

7.7.2 Assessment of Geotechnical Issues 7.7.2.1 At-grade and Embankment Sections It is likely that the over-consolidated soils will provide a suitable road formation for any at-grade sections of the route. The final subgrade and pavement designs will likely need to be informed by site specific testing (index and CBR). Where low embankments are constructed on the over-consolidated deposits then embankment settlement and bearing capacity issues are not anticipated to be a major concern. The stability of the embankment side slopes will need to be assessed, although the 1:6 side slopes proposed are very shallow. The stability assessment will need to consider the nature of the embankment fill and also the strength of the underlying deposits – particularly the presence of any low shear strength / pre-existing shear planes in the clay. The source and suitability of fill material for embankments will need to be assessed, along with the geotechnical reuse characteristics of any site-won material, or, if necessary, disposal requirements. Similarly the possible presence of contaminated materials during any excavation works will require consideration, in particular their potential to do harm during construction and their disposal.

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The section of the route underlain by alluvial soils adjacent to Liden Brook is to be formed on embankment. The lateral and vertical extent, and the nature of these deposits is currently unknown. Key considerations will be settlement and bearing capacity of the embankment, and the stability of the side slopes. This assessment will need to be informed by site specific investigation, and subject to the results consideration of ground treatment or excavation and replacement may be needed. The design of the embankments will also need to consider any issues associated with the flood risk in the area, particularly if the flanks of the embankment will be subject to elevated flood water levels for any length of time. 7.7.2.2 Structures The bearing and settlement potential will need to be assessed at all structure locations in order to verify the most appropriate foundation type for each structure, and also the depth and size of the foundation required. This assessment will need to be informed by site specific investigation and, subject to the results, consideration of deep foundations such as piles, ground treatment or excavation and replacement may be needed. In particular, the make-up and depth of and any alluvial material associated with the brook that crosses the site is unknown. If the underlying soils are soft and cohesive then piled foundations may be required.

The over-consolidated clay soils present at the site can restrict the driveability of piles. If driven piled foundation solutions are preferred, an assessment of driveability will be required in order to determine whether piles can achieve sufficient embedment depth. Bored or continuous flight auger (CFA) piling types are typically considered more suitable for the ground conditions envisaged to be encountered. Where it is proposed to used cut and cover techniques to implement an underpass, ease of excavation of the underlying soils should be assessed which will need to be informed by site investigation including strength testing of the material encountered. Similarly the stability of any temporary excavations will need to be assessed in order to determine appropriate temporary batter gradients and/or benching or support requirements. The presence of low permeability soils underlying the route indicates that seepage into the excavations may not be significant, however an allowance for pumping should be made as there is potential for surface water flooding and also high groundwater levels in the area. The geotechnical reuse, disposal and contamination characteristics of any site-won material from the underpass excavations, and other structure locations, should be considered. The potential for chemical attack on buried concrete from aggressive soils will need to be assessed as both the Kimmeridge and the Gault Clay Formations are potentially high sulphate bearing formations.

7.8 Environmental and Contaminated Land Issues A detailed assessment of environmental and contaminated land issues has not been carried out as part of this desk study. Key observations from the Envirocheck® report are summarised below. No information regarding landfills is collected in the Envirocheck® report (Ref 3). Localised fly tipping on the agricultural land through which the route passes may give rise to highly localised minor pollution incidents. The Envirocheck® report indicates that the route passes through a nitrate vulnerable zone. This is a classification given to land where excessive use of nitrate, mostly derived from agricultural fertilisers is known to cause significant ecological damage. The Envirocheck® report further notes that the southern connection of the proposed route, at Pack Hill, Moor Leaze Farm, passes through a designated Area of Outstanding Natural Beauty.

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 7-11 SECTION 7 7 GEOTECHNICAL ASSESSMENT 7.9 Recommendations for Ground Investigation An initial ground investigation is recommended to provide outline geological and geotechnical data along the proposed route. It is possible, depending upon the development of outline design, that a second phase of intrusive investigation would be required at a later date directed at the locations of the structures required along the road link. As an indication of the ground investigation that is likely to be required, it is envisaged that a series of boreholes and trial pits will be formed at approximately 100m centres along the proposed route with borehole depths dependant on the height of the proposed embankments, or depth of the cuttings, but always deeper than 6m or 2m from the base of the structure. The ground investigation required at the locations of proposed structures will be dependent upon the nature and intended layout of the structures with a minimum of two investigation points per foundation. At least two boreholes per foundation are also likely to be required and at each point where a crossing of the route with existing tributaries or existing structures occurs. Suitable sampling should be undertaken from the exploratory holes formed to enable a suite of laboratory testing to establish geotechnical strength and deformation parameters, material re-use characteristics and chemical properties. These tests should include: Classification tests to include moisture content, particle size distribution and plasticity classification for clay soils; Total and effective stress shear strength tests; Consolidation and compressibility tests; Optimum moisture content and maximum dry density tests; Soil pH and sulphate content tests; A standard suite of contamination screening tests should also be undertaken on the recovered soil samples. Possible constraints on the progress of the ground investigation include: Land access rights; Buried and overhead services; Existing buried and above ground structures; Public rights of way; Heritage, archaeological and environmental issues; Possible soil contamination. Installation of piezometers for monitoring in actively farmed agricultural land.

7.10 References 1. Ordnance Survey. 1998. 1:25,000 scale Explorer Sheet 169 -Cirencester & Swindon, Fairford & Cricklade. 2. Zetica Ltd. Unknown date. Unexploded Ordinance Risk Map for Wiltshire. Downloaded by HGL from www.zetica.com on 29/01/14 3. British Geological Survey 1974 1:63 360 Scale Sheet 252 Swindon, Solid & drift Geology.

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4. Landmark Information Group Limited. 2008. Envirocheck report for Swindon Borough Council. Order Number: 24800499_1_1 dated 26 March 2008. 5. Halcrow Group Limited. Apr 2008. Swindon EDA Canal Geotechnical Desk Study. Report Ref. WNSEDA for Swindon Borough Council. 6. Halcrow Group Limited. Feb 2006. 64KF Wanborough Road, Swindon, Ground Investigation Interpretative Report. Report No. WE/TWWR/22/188 for Thames Water. 7. BSI. 2007. Eurocode 7 Geotechnical design. Part 2: Ground investigation and testing. Annex B

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SECTION 8 8 Environmental appraisal

This section details the findings of an initial desk-based study undertaken as part of the feasibility study to identify the potential environmental issues, constraints and opportunities associated with potential road alignment options, and to identify the requirements for further environmental assessment of the preferred option. This appraisal addresses a range of topics and is based on available baseline information and readily available web-based information including: - Biological Records Data from the Wiltshire and Swindon Biodiversity Records Centre (WSBRS) (Appendix A) Ecological Appraisal (Appendix A) The study area for this environmental appraisal encompasses a predominantly rural area adjoining the eastern edge of the A419 with the northern boundary dictated by Wanborough Road, the eastern boundary comprising agricultural land and the southern boundary extending to the Commonhead Roundabout (see Figure 1). It principally comprises the footprint of the proposed options (based on alternative speeds), with a surrounding buffer zone of up to approximately 200m. At the time of writing the report (February 2014), the south west region including the Swindon area, had been experiencing a prolonged period of rain leading to flooding. This affected the site by raising river and watercourse levels to a point where it was considered to be unsafe to undertake the survey. A Phase 1 survey could be undertaken at the time of the report, although the period between October to March is considered a sub-optimal time as much of the flora is still dormant. In order to make the ecological survey as robust as possible for the feasibility study, a full survey later in the year would need to be carried out. Alternatively, it was possible to undertake an initial Phase 1 followed by recommendations for a brief check on habitats later in the year. To meet client deadlines and taking into consideration the time of year and current water levels on the site, it was agreed to postpone a full walkover survey, undertake an initial Phase 1 survey and make recommendations for a brief check in habitats later in the year (from mid-April onwards). 8.1 Existing Environment

The key environmental features within the study area are described below and where these present constraints or opportunities to the implementation of the proposed options are shown in Section 8.2. Approximate location and extents of constraints (subject to Phase 1 survey findings) are shown on Drg No TH/SBCC/230/HIG/102.

8.1.1 Local Community The study area is sparsely populated and comprises several isolated properties and farmsteads including Moorleaze House, Meadow House, Great Moor Leaze Farm and part of Applegate House. There are no known businesses in the study area (agricultural activity is described in Section 1.5 ‘Land Use’.

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 8-1 SECTION 8 8 ENVIRONMENTAL APPRAISAL 8.1.2 Flora and Fauna An ecological appraisal of the flora and fauna within the study area undertaken by CH2M Hill in February 2014 is provided in Appendix A ‘Ecological Appraisal’ and summarised below. Records of protected and notable species from Wiltshire and Swindon Biodiversity Records Centre (WSBRS) are also provided in Appendix A. There are no international or national nature conservation sites within the study area. The only designated site that lies within the study area is the River Cole Local Wildlife Site (LWS); a non- statutory area of local importance for nature conservation, comprising a river complex draining water from Swindon into the River Thames. There are other LWS’ within 1km of the scheme boundary and these are described in Appendix A. Habitats present within the study area comprise arable land, semi-improved grassland, broad-leaved woodland, scattered broad-leaved trees, hedgerows, scrub and waterbodies. The River Cole crosses the study area at the southern and mid-section of the study area with a number of field drains throughout. Towards the northern end of the study area are plantation and woodland areas. Four known ponds are located within the study area; one within the immediate boundary of Great Moor Leaze Farm, the other three as a field ponds within the hedgerow systems. The following habitats of principal importance under the Natural Environment and Rural Communities Act 2006 are known to be present within the study area: arable field margins, hedgerows, ponds, rivers, lowland meadows and lowland mixed deciduous woodland. The habitats within the site have the potential to support great crested newt Triturus cristatus, badger Meles meles, bat species, breeding birds, otter, reptiles, water vole Aricola amphibious, white-clawed crayfish Austropotamobius pallipes and notable plant species. There are no biological records of invasive plant species within the study area (Wiltshire and Swindon Biodiversity Records Centre (WSBRS). The existence of Tree Preservation Orders would need to be investigated as they would also need to be considered in any detailed appraisal of the options. An extended Phase 1 Habitat Survey will be carried out in Spring 2014 when recommendations for protected species surveys will be provided.

8.1.3 Landscape and Visual Amenity The southern end of the study area (area at and to the south of Moor Leaze) is located within the North Wessex Downs Area of Outstanding Natural Beauty (AONB); an area designated to conserve and enhance the natural beauty of the distinctive landscape character. Within the AONB, the study area is classified as lying within the Wanborough Vale landscape area. The key characteristics of this area include: almost entirely level, flat Plain forming part of a much wider Vale landscape that extends beyond the boundary of the AONB. The rising scarp to the south is a dominant feature; drained by the streams rising on the scarp which flow north to form the headwaters of the River Cole; a mixed pasture and arable landscape with fields being medium scale and bounded by a network of hedgerows with abundant hedgerow trees; field pattern dominated by Parliamentary enclosure with more recent boundary removal to create a very open landscape;

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distinct ‘urban fringe’ character due to the presence of the M4 and A346 and recent development on the edge of Wanborough plus views to the edge of Swindon. Key issues in Wanborough Vale of the AONB (Land Use Consultants 2002) are described as: - urban fringe character - dominant influence of the road network - M4, A419 (T); recent residential development at Wanborough and views to the edge of Swindon; in the past intensive farming leading to loss of environmental assets particularly biodiversity by drainage and cultivation of permanent pasture; loss of hedgerows boundaries and some mature hedgerow trees, plus poor management of remaining hedgerows; vulnerable to the impact of development on the steep scarp slope to the south (borrowed landscape dominant in view). The landscape character of the study area has been assessed and classified by Swindon Borough Council in their Landscape Character Assessment (Swindon Borough 2011 Revised Deposit Draft – Swindon Borough Council 2004). The country park is classified as lying within the Vale of the White Horse landscape and those relevant characteristics include: broad, flat low lying valley extensive views towards the Downs and Midvale Ridge numerous small streams flow across the vale from south to north, joining the River Cole, and numerous ponds. fields bounded by hedgerows with scattered standard trees. large fields with a strong north to south linear pattern following Parish boundaries. a deserted mediaeval village adjacent to Wanborough, the disused Wilts & Berks canal runs along the northern boundary. substantial tree cover pre 1970 (Dutch Elm disease). Visual receptors within the vicinity of the study area include residents within adjacent residential properties; vehicle travellers on the local road network including the A419 and users of public spaces such as footpaths.

8.1.4 Water There are no groundwater protection zones within the study area. A groundwater nitrate vulnerable zone lies approximately 700m to the east of the proposed study area. This is a classification given to land where excessive use of nitrate, mostly derived from agricultural fertilisers is known to cause significant ecological damage. According to an Envirocheck Report (2008) prepared as part of the geotechnical desk study (see Appendix A of main feasibility report), a small part of all options is underlain by a minor aquifer of ‘variable permeability’ at Liden Brook. In terms of groundwater vulnerability, the remaining parts of the options are described as a ‘non aquifer of negligible permeability’. The Liden Brook main river flows in a northerly direction through the study area. Parts of the study area lie within a high risk flood zone (Flood Zone 3) as defined by the Environment Agency. Three pollution incidents on controlled waters have been recorded within the study area.

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The Water Framework Directive (WFD) 2000/60/EC requires all natural water bodies to achieve both good chemical status and good ecological status (GES) and Good Ecological Potential (GEP) for artificial and heavily modified water bodies. The study area falls within the Thames River Basin Management Plan (RBMP – Environment Agency 2009), which outlines the actions required to enable the Liden Brook waterbody to achieve GES. Further consideration will need to be given to this water body, which will be affected by the construction of a new road. 8.1.5 Land Use The study area, which is predominantly flat, encompasses a range of land use classifications, principally Grade 3b agricultural land (land of moderate value for crop production) (post 1988 ALC data), isolated properties/farm holdings, a stable block adjacent to Wanborough Road and the road infrastructure. It is understood that there are various options proposed to reinstate and link the Wiltshire and Berkshire Canal, which connected the Kennett and Avon Canal at Semington to the River Thames at Abingdon. Land within the study area is safeguarded by policy EN11 in the Local Development Framework (Swindon Borough Council 2013) for the delivery of the canal with a view to its long-term re-establishment as a navigable waterway.

8.1.6 The Historic Environment There is one Scheduled Monument lying within the study area at the northern extremity; the Site of Roman Town, West of Wanborough House, which has the potential to be directly or indirectly (e.g. setting) affected by the works. This is considered to be the nationally significant former roman settlement of Durocornovium (Swindon Borough Council 2013). There is also an Area of Archaeological Importance within the study area Drg No TH/SBCC/230/HIG/102 No other designated heritage assets lie within the footprint of the road or within the study area. The following listed buildings lie within 1km of the study area: Over 20 listed buildings - located within Upper and Lower Wanborough, at a minimum of 700m east of the study area Milestone (Grade II) – located on Purley Road approximately 700m to the south of the study area Lake Cottage (Grade II) - located approximately 150m to the east of the study area Moat Cottage (Grade II) - located approximately 150m to the east of the study area Foxbridge Farmhouse (Grade II) - located approximately 400m to the north-east of the study area Wrightsbridge House Farmhouse and Coachhouse (Grade II) - located approximately 400m to the east of the study area to the east There is the potential for buried archaeological features or buildings of cultural heritage value within the study area. Consultation should be undertaken with the County Archaeologist and English Heritage in relation to the presence of archaeological features and the archaeological resource within the study area. A focussed archaeological desk-based assessment (DBA) is likely to be required (dependent on road alignment) to enable further assessment of the archaeological potential in and around the proposed road.

8-4 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 8 8 ENVIRONMENTAL APPRAISAL 8.1.7 Transport and Access The study area borders the eastern boundary of the A419. The A419 runs in a north/south direction connecting Cirencester to the north-west of the study area and Junction 15 of the M4 motorway to the south of the study area. Two minor roads run through the study area; Pack Hill, which links the Commonhead roundabout on the south-western boundary of the study area to Wanborough, and The Marsh, which links Pack Hill to Wanborough Road along the northern boundary of the study area. A couple of Public Rights of Way pass through or around the study area.

8.1.8 Geology/Contaminated Land The study area is dominated by soils from the Upper Jurassic Kimmeridge Clay Formation (sandstone) and Gault Formations (mudstone), which underlies the Vale, with Quaternary alluvium along the course of the Liden Brook. There are no known recorded landfills within the study area, however, there may be other potentially contaminated land uses in the area.

8.2 Appraisal of Environmental Issues, Constraints and Opportunities

Table 8-1 provides a summary of potential environmental issues, constraints and opportunities resulting from the construction and operation of the alternative flood risk management options under consideration (see Section 5). The table shows the environmental issues, constraints and opportunities associated with all options except where stated otherwise.

TABLE 8-1 Potential key environmental issues, constraints and opportunities relating to road options under consideration

Receptor Issues and Constraints Opportunities Local Potential property blight (including Opportunities for the road design to Community potential for loss of light, privacy integrate noise reduction measures etc) with associated changes in land such as changes in vertical access and land values alignment, siting road in cutting, Potential severance of some wherever possible, constructing properties (e.g. Great Moor Leaze noise barriers, shielding noise- Farm and Moorleaze House) sensitive dwellings (e.g. Appleton House) and use of quiet road Significant increases in noise, surfaces. vibration, airborne contaminants

and disruption due to construction traffic affecting sensitive receptors in and around the study area. Long-term increase in airborne

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TABLE 8-1 Potential key environmental issues, constraints and opportunities relating to road options under consideration

Receptor Issues and Constraints Opportunities contaminants upon completion of road from vehicle exhaust emissions Long term increase in noise and vibration upon completion of road for local residents, agricultural properties, users of footpaths, livestock and fauna – those options with a lower speed limit are likely to generate less noise Temporary increase in local employment during construction Flora and fauna Potential to adversely impact on Opportunity to provide additional River Cole LWS habitat features for protected and Direct loss of terrestrial habitat notable species, new planting and (including hedgerows/trees) within enhanced habitat connectivity as an the footprint and disturbance integral part of the scheme design. to/fragmentation of adjacent Opportunities for river enhancement habitats. and improvements to the condition Direct damage and disturbance to of the River Cole LWS and Liden species, with potential to affect Brook, and accommodate linkages legally protected and of with green infrastructure and conservation concern (protected recreation/amenity. species to be identified following Phase 1 Habitat Survey in April 2014 and associated protected species surveys. Landscape and Potential effects on character of Opportunity to design a scheme that visual amenity Wessex Downs AONB – southern limits the loss of mature hedgerow part of road located within AONB. trees, and improves the Changes in landscape character on management of remaining rural/urban fringe due to presence hedgerows. of new man-made structures on currently undeveloped land, particularly where road will be constructed on embankment. Deterioration in existing views due to presence of new road and associated construction – changes in views for visual receptors including local residents, agricultural properties, users of footpaths and local roads.

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TABLE 8-1 Potential key environmental issues, constraints and opportunities relating to road options under consideration

Receptor Issues and Constraints Opportunities Water Development of road within parts of Opportunities to deliver mitigation the floodplain with potential to identified in the Thames RBMP exacerbate flooding. Risks to water quality in Liden Brook (with associated impacts on River Mole) from construction activities and flooding of new road, with associated impacts on ecology Potential effects on groundwater levels and quality within NVZ and minor aquifer Impacts on drainage Land use Relocation of existing stable block No opportunities identified adjacent to Wanborough Road required Loss of and severance of Grade 3b agricultural land Options must not prejudice the delivery and reinstatement of the Wiltshire and Berkshire Canal. Historic Effects on the setting of Potential reduction in flood risk to environment Durocornovium, the Site of Roman built heritage assets as a result of Town Scheduled Monument and flood risk management and drainage nationally significant site (and measures associated with new potential vibration) and Areas of scheme Archaeological Importance will require sensitive management Potential damage to unknown archaeology within footprint of the scheme including impacts on the Area of Significant Archaeology Significant Unscheduled See Table 8-2 Archaeological Feature adjacent to Pack Hill Transport and Disruption to use of public Provision of strategic infrastructure Access footpaths, resulting from that may benefit wider areas of construction and operation of the Swindon new road Improves accessibility and Likely loss of access to existing connectivity between local footpaths/public rights of way communities and new residential crossing the new road developments

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TABLE 8-1 Potential key environmental issues, constraints and opportunities relating to road options under consideration

Receptor Issues and Constraints Opportunities Disruption to and potential damage Potential to integrate with green to access along adjacent local roads infrastructure, in accordance with during construction including the Emerging Local Plan potential traffic congestion, and need to ensure good integration with existing road network Geology/ Unknown risks of contamination No opportunities identified Contaminated from previous/adjacent land uses Land

8.3 Further Work and Environmental Consenting

Potential issues, constraints and opportunities identified from this initial environmental appraisal relating to the options under consideration are described in Table 8-1. Following this feasibility study, further environmental assessment will be required (see Table 8-2) to address these potential issues, in support of an application for planning consent for the proposed scheme from the developer.

It is recommended that consultation on this Feasibility Report is undertaken with key stakeholders: the Environment Agency, Natural England, English Heritage, Swindon Borough Council and Wiltshire County Council. The feedback received from continued consultation should be used to inform the scope of future environmental assessments. As part of this consultation, a formal screening and scoping opinion should be sought from Swindon Borough Council regarding the requirement and scope of a statutory Environmental Impact Assessment (EIA) under the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 to support the application for planning consent. It is likely that a statutory EIA will be required as the proposed road scheme would fall under Schedule 2 of the Town and Country Planning (EIA) Regulations.

In addition to the likely requirement of a statutory EIA, Table 2 identifies further surveys and investigations, and additional consultation that this initial appraisal has identified are required to address identified gaps in baseline information (e.g. protected species and the potential for undiscovered archaeology), and/or meet legislative or procedural requirements..

TABLE 8-2 Further investigations/consultation likely to be required (independent of any requirement for formal EIA)

Receptor Further investigations/consultation required Local Community Consultation with Swindon Borough Council Environmental Health department

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TABLE 8-2 Further investigations/consultation likely to be required (independent of any requirement for formal EIA)

Receptor Further investigations/consultation required to determine the requirement for any formal noise, air quality and vibration assessments or management measures Review of legislative framework, planning policy/guidance and plans/objectives of others in and around the study area to identify potential conflicts and opportunities Flora and Fauna Habitat suitability/targeted species surveys (see Appendix A for details) including consideration of protected hedgerows and invasive species – to be defined following the Phase 1 Habitat Survey in April 2014 Landscape and Landscape and visual impact assessment, informed by site visit by landscape visual amenity architect Water WFD assessment to determine the impacts of the proposals on the Liden Brook water body in accordance with Environment Agency guidance Flood risk assessment in accordance with current guidance Land Use Liaison with landowners, tenant farmers and the Canal Trust to discuss the proposals Historic Detailed desk-based assessment to review the archaeological background to the environment study area and the historic landscape, and to form a preliminary view of archaeological potential in the affected area. This would also consider issues such as the settings of Listed Buildings in consultation with the Swindon Borough Council Conservation Officer and in accordance with the National Planning Policy Framework (NPPF). To be followed by field evaluation, if required, in consultation with the Conservation Officer. These investigations will be undertaken to inform planning determination Transport and Consultation with the highway authority – Wiltshire County Council to determine Access the requirements for and potential scope of any transport assessment relating to construction traffic Geology/Contami Ground investigation (trial pits and supplementary percussion holes), involving in nated Land situ and laboratory testing to inform the design

8.4 References

Swindon Borough Council (2012): Swindon Borough Local Development Framework: Swindon: Planning for our future Pre-Submission Document

Swindon Borough Council (2013): Swindon Borough Council Local Development Framework: Eastern Villages Draft Supplementary Planning Document

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SECTION 9

9 Statutory undertakers & stakeholders

9.1 Public utilities CH2M Hill issued C2 notices to utilities companies in the Swindon and Wanborough area to identify the approximate locations of existing utilities. This was used at feasibility stage to identify utilities affected by the EVSCR and approximate scope of the works required to divert utilities for indicative costing purposes. This C2 enquiry only includes for known services. Private services e.g. gas, water, telecoms to individual properties and businesses are not shown on responses but should be anticipated. The approximate location and extent of existing utilities is shown on Drg No TH/SBCC/230/HIG/103. 9.1.1 Public utilities present affected The following public utilities are present in the area and could potentially be affected by the proposed EVSCR.

TABLE 9-1 Public utilities within the search area – details received

Company Utilities present Comments

British Telecom Openreach Various telecommunications Overhead cables

Instalcom - GC & Fibrenet Fibre optic cables Limited to Wanborough Road and A419

Instalcom – Level 3 Fibre optic cables Limited to Wanborough Road and A419

Orange Please be advised that from the 1st October 2013 May Gurney no longer provide the Plantsearch service on behalf of Orange. We are currently waiting to be advised who will be providing this service in the future and shall update this message as soon as we are able.

Scottish & Southern Energy

Thames Water Major 600mm water supply main on a north-south alignment

Virgin Media Restricted to Pack Hill

Vodafone Restricted to Commonhead junction area

Wales & West Utilities Low pressure gas main Overhead electricity cables – reduced clearance Intermediate pressure gas main High voltage electricity Low voltage electricity

Geo Networks Ltd. Restricted to Commonhead junction area

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At time of preparing the feasibility study, several utilities C2 submissions had not been received.

TABLE 9-2 Public utilities within the search area – details not received

Company Utilities present Comments

Orange Telecommunications

May Gurney (Kier Group) Plc. Telecommunications

McNicholas Constructions Utilities Ltd.

SSE Telecoms Plc.

ESP Utilities Gas

Vtesse Networks Telecommunications

TABLE 9-3 Public utilities not affected

Company Utilities present Comments

Verizon Business (MCI, Worldcom. MFS) Telecommunications

Fujitsu Telecommunications Europe Ltd. Telecommunications

AboveNet UK Ltd. Telecommunications

Affiniti (KCOM Group Plc.) Telecommunications

Network Rail Rail

GTC UK Utilities

BskyB Telecommunications

Energetics Electricity Electricity

Interoute IT

Trafficmaster Traffic

Fulcrum Pipelines Ltd. Utilities

Southern Gas Networks Gas

9-2 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 9 9 STATUTORY UNDERTAKERS & STAKEHOLDERS 9.1.2 Anticipated public utilities diversionary and protection works At the feasibility stage, the utility companies have not been contacted regarding specific diversions and new works associated with the EVSCR. This will form part of any future preliminary design stage. Based on the proposed alignment options, it is anticipated that the following works to existing utilities (subject to discussions with the relevant utility company) could be required:

TABLE 9-4 Public utilities – anticipated works

Location Company Utilities affected Size Anticipated Works

Ch 130 Swindon Borough Highway drainage Varies Diversion / protection Pack Hill Council

Ch 130 Thames Water Water supply 4 in Diversion / protection Pack Hill

Ch 130 Thames Water Water supply 180mm Protection Pack Hill

Avoid extensive works to this strategic water Ch 130 supply main. EVSCR alignment to limit works to Thames Water Water supply 600mm Pack Hill protection such as slabbing over at crossing points

Ch 130 Diversion / protection for footway/cycleway from Virgin Media Fibre optic cables Pack Hill Commonhead Rbt to Pack Hill

Ch 130 Vodafone Fibre optic cables Diversion / protection Pack Hill

Water supply - Leave in place subject to agreement with Thames Ch 180 Thames Water Unknown disused Water

Ch 400 - 500 Thames Water Foul water main 150mm Diversion / protection

Scottish & Southern Ch 590 Overhead cables 11kv HV Diversion Energy

Ch 630 Thames Water Water supply 4 in Diversion / protection

Water supply - Leave in place subject to agreement with Thames Ch 880 Thames Water Unknown disused Water

Avoid extensive works to this strategic water supply main. EVSCR alignment to limit works to Ch 970 Thames Water Water supply 600mm protection such as slabbing over at crossing points

Avoid extensive works to this strategic water supply main. EVSCR alignment to limit works to Ch1350 Thames Water Water supply 600mm protection such as slabbing over at crossing points

Wales & West Intermediate Possible protection slab depending on depth of Ch 1350 Gas main Utilities pressure service

Ch 2390 Diversion for carriageway widening associated Wanborough Instalcom - GC Fibre optic cables with at-grade route crossing Road

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TABLE 9-4 Public utilities – anticipated works

Location Company Utilities affected Size Anticipated Works

Ch 2390 Diversion for carriageway widening associated Wanborough Instalcom - Fibrenet Fibre optic cables with at-grade route crossing Road

Ch 2390 Wanborough BT Openreach Overhead cables Diversion Road

Ch 2390 Underground Wanborough BT Openreach Diversion / protection cables Road

Ch 2390 Diversion for carriageway widening associated Wanborough Instalcom – Level 3 Fibre optic cables with at-grade route crossing Road

Ch 2390 Wanborough Thames Water Water supply 6 in Diversion / protection Road

Ch 2390 Wales & West Wanborough Utilities Gas main Low pressure Diversion / protection Road

Ch 2390 Possible protection slab depending on depth of Wales & West Intermediate Wanborough Gas main service. For at-grade options widen carriageway Utilities pressure Road on southern side

Ch 2390 Scottish & Southern Low voltage Wanborough Diversion for new road alignment Energy electricity Road

Ch 2050 - Scottish & Southern High voltage 11kV 30x3w Diversion of overhead cables for new road 2400 Energy electricity AAAC alignment and existing low clearances.

Scottish & Southern High voltage Diversion of overhead cables for new road Ch 2390 11kV .05x3w Energy electricity alignment and existing low clearances.

A419 access to Property Instalcom - GC Fibre optic cables Avoid damage during closing of existing access A

A419 access to Property Instalcom - Fibrenet Fibre optic cables Avoid damage during closing of existing access A

TABLE 9-5 Public utilities – anticipated works – Pack Hill widening

Location Company Utilities affected Size Anticipated Works

Underground Diversion / protection Pack Hill BT Openreach cables

Swindon Borough Pack Hill Street lighting Replacement street lighting Council

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TABLE 9-5 Public utilities – anticipated works – Pack Hill widening

Location Company Utilities affected Size Anticipated Works

Swindon Borough Diversion / protection Pack Hill Highway drainage Council

Pack Hill Virgin Media Fibre optic cables Diversion / protection

Pack Hill Vodafone Fibre optic cables Diversion / protection

9.1.3 Scottish & Southern Energy There are several 11kv high voltage overhead cable routes along the alignment of the EVSCR. Some of these have reduced headroom which may restrict the vertical alignment of the EVSCR. It is recommended that these are diverted for purposes of the new EVSCR and construction operations. 9.1.4 Thames Water There is a 600mm diameter water supply main running on a north-south alignment from the Wick Lane pump house to beyond Pack Hill. This main is connected into East Swindon and the Dorcan industrial estates under the A419. The proposed EVSCR alignment and associated earthworks shall minimise encroaching close to the water main where possible. This needs to take into consideration any future maintenance work to the water main by Thames Water including undertaking excavations which may affect any EVSCR earthworks stability. At preliminary design stage the depth of the water main will need to be determined and proposals including protection discussed with Thames Water. 9.1.5 Wales & West Utilities There are two intermediate gas mains present that could be affected by the EVSCR: north of Wanborough Road – if an at-grade solution is adopted, it would be better to widen south of Wanborough Road to minimise impact on the main west-east across the site The depths of these mains and protection measures will need to be discussed at preliminary design stage. 9.1.6 New public utilities works The EVSCR will provide a link between the Eastern Villages development and the A419 Commonhead junction / Pack Hill area. The EVSCR will provide an opportunity for utility companies to install new or redirect existing supplies along the road corridor. To facilitate this and future footway/cycleway routes, verge areas will be provided on both sides of the road. The EVSCR would be constructed at a level that will keep vulnerable services above the 1 in 100 year flood risk level.

9.2 Stakeholders 9.2.1 Fire Service and Fire Safety The Wiltshire Fire and Rescue Service (WFRS) Community Risk Strategy for Swindon Borough 2006 to 2026 (2011) highlights the importance of community safety in delivering sustainable development. The Strategy

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 9-5 SECTION 9 9 STATUTORY UNDERTAKERS & STAKEHOLDERS identifies that the infrastructure and capacity within the current fire service facilities will be insufficient to deal effectively with the projected growth of incidents generated in part by the Eastern Villages. The growth of Swindon a redistribution of assets is proposed including the provision of new fire stations and co-location with other emergency services, particularly the Ambulance Service to help manage growth and meet future requirements. The proposals includes a requirement to deliver a new fire station towards the south east of the Swindon urban area. The preferred site for the Fire Service is set out in emerging Local Plan as land adjacent to Great Western Hospital. However, if that site proves to be undeliverable then land at the southern end of the new Eastern Villages area should be safeguarded for a new fire station. For this reason land at the southern end of the Eastern Villages development south of Foxbridge village will safeguarded in accordance with Policy NC3.

9.2.2 Ambulance Service and Health Facilities The Eastern Villages is well positioned to provide access to the Great Western Hospital off the A4259 Marlborough Road. Swindon Borough is served by the Great Western Ambulance Service (GWAS) with services currently delivered from the Swindon Ambulance Station in Queen’s Drive and standby points at the Link Centre and the Northern Orbital Centre. In EVDSPD, the GWAS has previously identified that its requirements at the Eastern Villages will be limited to the provision of standby points. There are opportunities to deliver this service co-located either with the Fire Service or within the multi-agency / community buildings.

9.2.3 Wilts & Berks Canal Trust The Wilts & Berks Canal Trust (WBCT) have previously commissioned reports into the viability of restoring the canal in the Swindon eastern Development Area (Project 11). The most recent was produced in 2012 by the WBCT Engineering Committee. The preferred alignment was Halcrow’s Route 6 from the A419 underpass to Wanborough Road and SWK Route C from Wanborough Road to Acorn Bridge. The Safeguarded Canal Route in the Swindon Borough Council Draft Local Plan Pre-Submission 2026 Proposals Plan now reflects the WBCT desired route. This has been used as the approximate alignment of the Wilts & Berks Canal for purposes of this feasibility study. A canal and towpath structure similar to those used on the Wichelstowe housing development south of Swindon will be adopted for the feasibility study. This section forms part of the Swindon Canal restoration project. Indicative levels for the canal alignment have been assumed based on a draft study prepared by CH2M Hill and submitted to Swindon Borough Council for review. It is assumed that horse riders will dismount before entering the canal structure towpath. The vertical clearance from the towpath will be approximately 2.4m. This will assist is determining the vertical alignment of the EVSCR where it crosses the canal. If the preferred vertical alignment of the WBCT canal is confirmed prior to construction of the EVSCR, it is likely that it could be accommodated with localised adjustment of levels. 9.2.4 Environment Agency A section of the EVSCR will be located within an Environment Agency Flood Risk Zone 3. The Liden Brook is classified by the Environment Agency as a Main River. Construction of works on or near a Main River requires consent from the Environment Agency. This required to ensure that the works will not make existing flood risk worse, interfere with our work, and do not adversely affect the local environment, fisheries or wildlife.

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Consultations are in progress with the Environment Agency to determine the approximate flood level and size of structure(s) over their Main River Liden Brook. Further details are provided in Section 6.

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SECTION 10

10 Public Transport

10.1 Eastern Villages public transport proposals The Swindon Local Plan establishes the strategic planning framework for sustainable economic growth and the new Eastern Villages development. The growth allocation is the largest in the Borough and has been subject to significant strategic transport assessment to assess the cumulative transport impact to 2026. The planned public transport mitigation for the development includes: • A rapid transit link to Swindon Town Centre from the Eastern Villages serving and through the district centre as part of phase 1 of the development; • Additional public transport services to connect with Swindon and internally within the development; • A circa 1000 (3ha.) space Park and Ride site

10.2 Existing public transport 10.2.1 Existing bus routes There are currently three bus routes that use The Marsh and are affected by the proposed EVSCR: Thamesdown Transport Route 46A Swindon – Hungerford (operated under contract to Wiltshire County Council) Thamesdown Transport Route 48A Swindon – Marlborough (operated under contract to Wiltshire County Council) Goride CIC Route 90 Newbury – Swindon (operated under contract to Swindon Borough Council)

10.2.2 Existing bus stop locations There are currently two bus stops that will be affected temporarily during the construction phase The Marsh, Wanborough – outside Farncombe Burycroft, Wanborough – outside Cross Keys public house

Buses will not be able to stop at these locations during phases of the works. It is proposed that services to these stops will be temporarily diverted via Church Road –Kite Hill – Rotten Row utilizing existing bus stops. 10.2.3 Public transport proposals Within the Eastern Villages development there will be specific public transport proposals put forward as part of the development planning submission. Stop location and routes into Swindon and surrounding areas will be developed at this stage. Consultations with the bus operators will need to be undertaken to determine the demand and requirement for bus stops between Pack Hill and the Eastern Villages southern boundary. Introduction a route via the Great Western Hospital could be considered.

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SECTION 11

11 Non motorised users

11.1 Existing NMU provision The existing facilities for non-motorised users (NMUs) - pedestrians, cyclists and equestrians - are limited on the existing road network. There are a number of footpaths that cross the area under consideration – refer to Drg No TH/SBCC/230/HIG/101 for the existing layout.

11.2 EVSCR footways, cycle routes and bridleways In accordance with the Swindon Borough Council Eastern Villages Draft Supplementary Planning Document, safe cycle and pedestrian routes will be secured within all the proposed villages and opportunities to connect to the existing network will be maximised. The new routes will cater for utility and recreation to ensure that more sustainable travel is made more attractive, easier and direct. The new routes through the Eastern Villages development will include informal paths across the network and will connect with the existing urban area and provide safe access on into the neighbouring countryside and rural areas. Cycle routes are to be provided across the Eastern Villages development to link residential and employment areas with key services and facilities and provide for non-vehicular travel. Links into the wider network will also be provided to provide more sustainable connections to neighbouring villages and urban areas.

11.3 Footway / Cycletracks Within the Eastern Villages development it is proposed that opportunities to connect with the existing network and neighbouring villages and urban areas are to be maximised with routes catering for utility and recreation. Currently footway/cycleway provision at Wanborough Road and Pack Hill is limited to the following: footway from Merlin Way along Wanborough Road to the Lotmead Business Village footway/cycleway to the north of the Commonhead roundabout connecting into Pack Hill and Purley Road It is proposed to provide a 3.0m shared footway/cycleway from Pack Hill at Commonhead roundabout along the western side of the EVSCR to Wanborough Road. The existing footway along Wanborough Road finishing at Lotmead Business Village will be extended to tie into this new facility. The route would provide connectivity between Parish of Wanborough (centre) Footpaths 25, 24, 8 and 22 with the Eastern Villages development and the Commonhead / Coate areas. Indicative proposals for footway/cycleway provision are shown on Drg Nos TH/SBCC/230/HIG/110 - /118 , and /140 - /143. 11.3.1 Lighting of NMU routes Design guidelines from the Institution of Lighting Professionals (Technical Report 23) advise that for safety purposes, cycletracks are lit. The use of landscaping alongside footway/cycleways needs to be considered to avoid providing areas for concealment. The A419 and Wanborough areas are generally unlit and this is the

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 11-1 SECTION 11 11 NON MOTORISED USERS preference for the proposed EVSCR. At Commonhead roundabout there are pedestrian / cyclist facilities across the north of the roundabout between the A4259 and Purley Road. The provision of lighting for NMUs should largely be based upon local circumstances. In urban areas, it is recommended that where appropriate and feasible, routes should be lit, particularly at crossing points. Consultation may be required to assess appropriateness. As part of the Eastern Villages development, it is assumed that lighting would be provided within the residential area. NMU routes in rural areas should not normally include lighting unless there are specific requirements, which include: high flows of NMUs, particularly on adjacent and shared use NMU facilities; routes with intersections with rights of way and both minor and major roads falling below geometry standards (lighting used at a specific point to highlight danger); routes which form part of an identified school route, commuter route or other route; through any underpass (subject to environmental impact). At feasibility stage, it is assumed that the level of NMU usage will not require lighting provision because: levels of NMUs are expected to be relatively low the footway /cycleway will be adjacent to the EVSCR the route will be diverted away from the underpass route will comply with geometric standards adjacent embankments will have a relatively shallow batter (1 in 6) areas of landscaping providing concealment are not anticipated at this stage

11.3.2 Signing of NMU routes Clear signage of NMU routes will be provided. In addition, iron-on markings would be used on paved footway/cycleways. These are used elsewhere with the Swindon Borough area in order to reduce street furniture clutter and vandalism.

11.4 Footpaths There are a number of Swindon Borough Council footpaths that cross the alignment of the proposed EVSCR – Parish of Wanborough (Centre) FP 25, 24, 8 and 22. There are no National Trails that cross the site. A bridleway links The Marsh / Burycroft and Rotten Row in Wanborough. The location and approximate alignment of these footpaths and bridleway in Wanborough Central is shown on Drg No TH/SBCC/230/HIG/102. Typical footpath facilities are shown on Photos 12, 13 and 16. 11.4.1 Crossing point facilities As part of the proposals, footpaths will be provided with crossing points on the EVSCR. Based on the projected two-way daily traffic flow (2614 AADT) on the EVSCR it will be necessary to provide informal at- grade crossing points in accordance with TA 91 and Section 11.5 below. To afford additional protection to pedestrians using the crossing points, refuges will be provided. Typical layout of crossing points and cross sections are shown on Drg Nos TH/SBCC/230/HIG/130, /140 – 143.

Where Footpath 25 crosses the EVSCR a controlled crossing point will be provided. This will be of the equestrian Pegasus type to accommodate future upgrade of FP25 to a bridleway between South Marston and Wanborough.

11-2 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 11 11 NON MOTORISED USERS 11.4.2 Footpath proposals Refer to Table 11-1 below for details of works to existing footpaths

TABLE 11-1 Summary of Footpath Proposals

Swindon Borough Council Crossing Point Parish of Wanborough Comments Requirements Centre Footpath Ref

Swindon Borough Council have indicated an interest in establishing a north-south bridleway route between South Marston and Wanborough. FP25 is to be treated as future bridleway and crossing points established for future installation of equestrian holding bay and Signal controlled Pegasus crossing - Pedestrian 25 adjacent separate pedestrian crossing point. This will be a signal controlled Pegasus equestrian / pedestrian crossing point. refuge and equestrian holding bay The approximate location of where FP 25 crosses the EVSCR is Ch 1940 ( E419717, N184474) For further crossing point details refer to Drg No TH/SBCC/230/HIG/130

FP24 will cross the EVSCR at Ch 1390 (E419600, 183941). A pedestrian refuge crossing point will be provided. 24 Pedestrian refuge For further crossing point details refer to Drg No TH/SBCC/230/HIG/130

FP22 and FP8 are in close proximity to each other where they cross the EVSCR. It is proposed that they are combined west of the EVSCR to 22 follow FP8 and diverge at The Marsh. From here FP22 will continue north-east along The Marsh to rejoin its current alignment near Applegate House. This increases the length of FP22 by approximately 110m. Diversion of FP22 will permit the reduction in crossing points on the EVSCR. Diversion will require extinguishment of approximately Pedestrian refuge 300m of FP22. 8 The approximate location of where FP 8 crosses the EVSCR is Ch 570 (E419787, N183177). For further crossing point and footpath diversion details refer to Drg No TH/SBCC/230/HIG/130 & /151.

11.4.3 Footpath 22 diversion Currently Footpaths 8 and 22 diverge and cross the EVSCR at two separate points. This would require installation of two separate crossing point in the vicinity of the access to The Marsh. To reduce the crossing points it is proposed to combine FP8 and FP22 for a section, diverting FP22 along FP8 and The Marsh. For details refer to Drg No TH/SBCC/230/HIG/151.

11.5 Uncontrolled Pedestrian and Cycle Crossings 11.5.1 Selection of crossing point

Crossing points will generally need to be provided for the existing public footpaths and bridleway. The type of crossing point was selected in accordance with the guidance in TA91 Table 6/1 – reproduced below

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TABLE 11-2 Criteria for Suitability of Informal At-Grade Rights of Way Crossings

AADT (two-way)

Road Type Normally Appropriate Potentially appropriate Not Normally Appropriate

Single carriageway Below 8,000 8,000 to 12,000 Above 12,000

Dual carriageway Below 16,000 16,000 to 25,000 Above 25,000

Wide single carriageway - Below 10,000 Above 10,000

AADT - Average Annual Daily Traffic

The modelled traffic flows are 2614 AADT (two-way). This makes the use of an informal at-grade right of way crossing suitable.

Informal at-grade crossing points are classified as: Pedestrian and cycle crossing points (with/without refuge) Cycle priority crossings Equestrian crossing with holding area

The use of a pedestrian refuge will be suitable on the EVSCR. The preferred crossing width for pedestrian refuge islands is 2.0m. The preferred crossing width for cyclist refuge islands is 3.0m to 4.0m. At feasibility stage it was decided to opt for a 2.0m wide refuge with 3.0m crossing width until the cyclist demand is more defined. Tactile surfaces will be provided both at the dropped kerb approach to the crossing and within the refuge itself.

Typical layout of crossing points and cross sections are shown on Drg Nos TH/SBCC/230/HIG/130, /140 – 143.

11.6 Equestrians 11.6.1 Current equestrian requirements There are equestrian facilities at present in the area. The Marsh and Burycroft is frequented by equestrians. Warning signs are provided south of FP8 on The Marsh and on Burycroft west of the Cross Keys public house. Access is required for equestrians from The Marsh to fields around the Pack Hill area. There is a stable block area off Wanborough Road that is to be considered as part of the proposals as this would be directly affected by the EVSCR. Photos 11 and 29 relate to existing equestrian use in the area of the EVSCR. 11.6.2 Equestrian provision 11.6.2.1 Eastern Villages Southern Connector Road equestrian route Following consultations with Swindon Borough Council Rights of Way officers, a demand for an equestrian route, north – south along the EVSCR has been identified. This will link FP25, The Marsh and the Pack Hill area. An equestrian route could be provided to the east of the EVSCR subject to funding availability and sufficient demand. This will be a verge 3.0m in width to permit 2 horses to pass. A separation zone of 1.8m will be provided between road and the equestrian route. The route will be on embankment, but this batter will be

11-4 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 11 11 NON MOTORISED USERS flattened out to around 1 in 6 to blend in to the surroundings. A typical layout of the potential route and details are shown on Drg Nos TH/SBCC/230/HIG/110 - /118, /130 and /140 - /141. 11.6.2.2 Future north-south bridleway Consultation with Swindon Borough Council Public Rights of Way has indicated that the bridleway network would benefit from an upgrade of the existing north-south footpath from South Marston FP5 – Wanborough FP39 – Wanborough FP 35 – Wanborough FP25. This would provide a major artery connecting the existing bridleway network in Highworth and South Marston parishes with the existing network on the North Wessex Downs, via some minor unclassified roads. To accommodate this future aspiration, a signal controlled Pegasus equestrian/crossing point for FP25. For further details of crossing point layout refer to Drg No TH/SBCC/230/HIG/113 and /130.

11.6.2.3 Crossing facilities Footpath 25 At the time of the feasibility study, the exact numbers of equestrians that would use the improved bridleway route is unknown and would need to be determined during preliminary/detailed design. Consultations with Swindon Borough Council Rights of Way has provided details relating to existing usage of The Marsh and Burycroft which is frequented by equestrians. Warning signs are provided south of FP8 on The Marsh and on Burycroft west of the Cross Keys public house. Access is required for equestrians from The Marsh to fields around the Pack Hill area. Provision will be made as part of the EVSCR for future construction of equestrian roadside facilities in accordance with TA91 at the location where Wanborough FP25 crossed the EVSCR. The at-grade roadside holding pen will be grass verge. (If the soil is cohesive then this will be hard paved). With the future aspiration to create a bridleway along FP25, a signal controlled equestrian / pedestrian Pegasus crossing point would be provided at this point on the EVSCR. The carriageway crossing will have a 10m wide band of high friction surfacing at the bridleway crossing point. This will be the same colour as the carriageway (grey) to avoid unnerving the horses. The earthworks slope up to the crossing point (where raised above the surrounding area) will be flattened out to around 1 in 6 to blend into the existing ground and make the approach easier for equestrians. A typical layout is shown on Drg No TH/SBCC/230/HIG/130. 11.7 Non-Motorised User Audit NMUs are considered to be pedestrians, cyclists and equestrians. NMU Audits require particular consideration to be given to the needs of disabled people, who may use any of these modes or other equipment such as wheelchairs. The NMU Audit should consider the implications of schemes for NMU accessibility, safety, comfort and convenience.

The most likely stages for completion of NMU Audit Reports (in accordance with HD42) are: • Preliminary Design: During development of the preliminary design and prior to public consultation and the publication of draft orders (if required). • Detailed Design: During development of the detailed design. • Completion of Construction: Prior to, or shortly after, scheme opening. At this feasibility stage, a specific NMU Audit was not carried out although the concepts of the Audit process were applied in determining current and future requirements for pedestrians, cyclists and equestrians.

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 11-5 SECTION 12 12 LAND AND ACCESSES 12 Land and accesses

12.1 Land Swindon Borough Council have provided a land plan and details of the land parcel owners. Ownership is generally comprises: private owners Secretary of State for Transport trustees Diocese of Bristol housing developers

Details of the Land Registry title parcels with the preferred route superimposed are shown on Drg No TH/SBCC/230/HIG/101. 12.1.1 Land and property affected The individual landowners have not been contacted directly during the preparation of the feasibility study. Once the preferred route(s) are identified then landowners that could be directly affected will be contacted for purposes of survey and preliminary design of the highway, landscaping, drainage etc. Alternative access points will be provided to properties where affected. 12.1.2 Buildings affected 12.1.2.1 Wanborough Road stables The only buildings identified as being affected by the EVSCR alignment are the stable blocks approximately 150m south-east of Wanborough House on Wanborough Road – see Drg Nos TH/SBCC/230/HIG/114 - /118 and Photo 29 for further details. To move the road alignment away from Wanborough House, it will be necessary to construct on the line of or adjacent to the stable block. The at-grade options would still leave the stables in place but are likely to leave the location unsuitable for its current use. The stables would be relocated to a more suitable position away from the crossing point at Wanborough Road. Discussions on provision of alternative access points would need to be undertaken with the owner. 12.2 Accesses There are a number of accesses along the proposed EVSCR. These provide access to residential and farm properties, fields and the like and will need to be maintained as part of the EVSCR. This may require the realignment of the access point or the provision of additional field accesses. 12.2.1 Residential / Business Accesses The access points will be constructed in accordance with the geometric standards set out in TD41 Geometric Standards for Direct Access – typically Layouts 1, 2 and 3. The existing access widths, usage and turning requirements will be taken into consideration when providing access points. Where possible, accesses will be positioned on level ground. In order to reduce the number of direct accesses onto the EVSCR, consideration will be given to combining accesses to provide a single point of access. Typical details of accesses to residential and business properties are shown on Drg Nos TH/SBCC/230/HIG/131.

12-6 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 12 12 LAND AND ACCESSES 12.2.2 Wilts & Berks Canal Accesses With the future Wilts & Berks Canal restoration, there may be the opportunity to install additional access points off the EVSCR to provide access points for leisure requirements, maintenance and parking. 12.2.3 Farm Accesses At this feasibility study stage the movement of cattle between severed fields e.g. for milking herds or by periodic movements for changes of grazing. Consultation will take place with landowners at the preliminary design stage regarding any requirements for crossings by cattle. At feasibility stage, the provision of cattle creeps is not anticipated. A hard paved area will be provided for approximately 10-15m from the EVSCR to permit vehicles to pull off the highway and remove mud from wheels before entering the highway. New gates will be provided to the access roads or field accesses. Typical details of accesses are shown on Drg Nos TH/SBCC/230/HIG/131. Some typical existing field accesses are shown on Photos 14 and 22.

12.2.4 Access Proposals

12.2.4.1 Applegate House and Inlands Farm, Inlands Bungalow The Marsh will be stopped up to vehicles between Pack Hill and Applegate House as part of the EVSCR works. There will a junction providing access to The Marsh off the EVSCR, maintaining access to Applegate House and Inlands Farm Indicative details of the access proposals are shown on Drg No TH/SBCC/230/HIG/111. The new access will tie in at the position shown on Photo 15.

12.2.4.2 Meadow House, Moorleaze House & Great Moor Leaze Farm These properties currently have access to the highway from the Marsh near to its junction with Pack Hill. A new direct access onto the EVSCR will be formed in a similar location, whilst avoiding the Great Moor Leaze Farm property. Indicative details of the access proposals are shown on Drg No TH/SBCC/230/HIG/110. 12.2.4.3 Property A This property currently only has direct access onto the A419. With the proposed EVSCR, this property will have direct access onto the link road for the property and fields. This will be much safer for the property owner and road-users on the A419. It is proposed to close up the access point onto the A419. Discussions with the Highways Agency on closing up of the access would be required. Indicative details of the access proposals to Property A are shown on Drg No TH/SBCC/230/HIG/112 and Photos 34 and 35. 12.2.4.4 The Marsh The southern section of The Marsh has a number of field accesses. It is proposed to leave The Marsh carriageway in place to permit its use for access to fields. To assist this, a turning head will be constructed at the northern end of The Marsh prior to the point where it becomes severed by the EVSCR. Indicative highway proposals for The Marsh are shown on Drg Nos TH/SBCC/230/HIG/110 and /111. 12.2.4.5 Wick Lane This private road off Wanborough Road serving the Thames Water pumping house will remain unaffected.

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SECTION 13 13 Delivery Considerations

13.1 Introduction The Section sets out the considerations for delivery, including public acceptability, construction, programme, risk and indicative costs.

13.2 Public acceptability The purposes of the preparation of this feasibility report is to form part of the consultation process with the public and other stakeholders of Swindon Borough Council’s proposals for the Eastern Villages Southern Connector Road. This report will also be accompanied by an Executive Summary as a précis of the proposals and alternative alignments.

13.3 Construction 13.3.1 Construction period It is anticipated at feasibility stage that the construction period for the EVSCR with the overbridge option is in the region of 2 years. This is likely to be reduced with the at-grade options. 13.3.2 Site access points Points of access to the site on the existing local road network under consideration are; 13.3.2.1 Merlin Way / Wanborough Road The north of the EVSCR site could be served by access from Merlin Way and Wanborough Road. This would however be restricted due to existing local road network. Currently there is temporary a 7.5t weight restriction on Merlin Way between Covingham Drive and Kingfisher Drive. This temporary traffic regulation order is in place until December 2014. The alternative route takes vehicles along Covingham Drive – Dorcan Way – Kingfisher Drive. Kingfisher Drive is a traffic calmed residential area with a school. The weight restriction does not prevent vehicles from entering the zone for access, so use of the route by construction traffic in the Merlin Way area would need to be managed to minimise impact of the local area and residents. 13.3.2.2 Commonhead Roundabout / Pack Hill Access could be gained to the site from the south from Commonhead roundabout and Pack Hill. This would require a temporary access to be built off Pack Hill / The Marsh. The impact on the building of local historic interest (Great Moor Leaze Farm) and surrounding environment including drainage network and utilities would need to be considered. Liden Brook could be crossed using suitable temporary works such as a bailey bridge to permit construction north of the Brook. This access point would reduce the impact on the residential area around Merlin Way and Wanborough Road. 13.3.2.3 A419 Southbound / Pack Hill Opposite Wheatstone Road there is currently a direct access onto the A419 southbound for Property A. A temporary access of the southbound dual carriageway could be constructed north of this location to permit a southbound access into the site. It would be necessary to cross the Highways Agency ditchcourse and need to be constructed to avoid the flood risk area.

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Exit from the site would still need to be via Pack Hill / Commonhead junction to avoid a southbound merge onto the A419 causing conflict due to the proximity to the Commonhead junction. Northbound site traffic would still use Pack Hill to avoid adding further traffic onto the A419/A420 White Hart junction. Proposals for a temporary exit from the A419 would need to be discussed with the Highways Agency and would be an expensive option. 13.3.2.4 Phasing of the Eastern Villages and Public Opinion Recently the construction of the Eastern Villages development has been featured in the local media with regards to concerns on construction traffic accessing the site. Concerns have been raised over the possibility of construction traffic using Covingham, in particular Covingham Drive, Dorcan Way and Kingfisher Drive if Lotmead is built first. The Trigger Point phasing The phasing of the construction of the Eastern Villages is extremely important in determining the access points. The developer, Ainscough Strategic Land has provided assurances that there will be no planning application submitted before the Local Plan is finalised, and that when they are ready to submit, phase one will represent just 200 new houses. Construction of the proposed EVSCR as an access road would provide an alternative point of access for the development.

13.3.3 Pack Hill realignment/southern access to Wanborough (Ch 150 – 600) The realignment of the Pack Hill and The Marsh junction area can be built off-line. This will allow the new junction forming the southern access to Wanborough to be built with minimal disruption to vehicles using The Marsh and Pack Hill. Refer to Drg No Drg Nos TH/SBCC/230/HIG/120 & /121 for highway layout details.

13.3.4 The Marsh to Wanborough Road (Ch 640 – 2250) The new carriageway between The Marsh and Wanborough Road can be built off-line minimising disruption to vehicles using The Marsh. Access between Property A and the A419 must be maintained during construction unless alternative provisions can be made. Refer to Drg No Drg Nos TH/SBCC/230/HIG/121 - /126 for highway layout details.

13.3.5 The Marsh (Ch 150 - 620) The Marsh can remain open until the new link between Ch 150 – 700 is nearly complete. At this point it will be necessary to close the southern section of The Marsh for a period up to Pack Hill. Access would need to be maintained to the properties accessing Pack Hill (Moorleaze House, Meadow House, Great Moor Leaze Farm and The Dance Studio). Refer to Drg No Drg Nos TH/SBCC/230/HIG/120 & /121 for highway layout details. The Marsh is on several bus routes, so closure would require diverting via Church Road – Kite Hill - Rotten Row. This is an existing bus route. Once the section between Pack Hill and The Marsh is complete, then access and bus routes would be reinstated.

13.3.6 Wanborough Road – Options A1 & A2 (at grade junctions) Construction of an at-grade junction would require widening of the existing Wanborough Road carriageway for a cross roads or signalised junction. To minimise impact on the existing intermediate pressure gas main

13-2 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 13 13 DELIVERY CONSIDERATIONS in the northern verge, it is recommended to widen Wanborough Road to the south. Refer to Drg Nos TH/SBCC/230/HIG/115 & /116 for highway layout details. Due to limited road width available on Wanborough Road (in the region of 6.0m), it would be necessary to control traffic by temporary traffic lights or potential road closures. By building to the south of Wanborough Road, disruption could be reduced. Temporary closure of Wanborough Road would involve a lengthy diversion in excess of 7km so this should be avoided.

13.3.7 Wanborough Road – Option A3 (overbridge) The proposed structure for the road bridge over Wanborough Road considered at feasibility stage is an in- situ concrete deck and pre-cast concrete beam superstructure supported bank seats on top of reinforce earth abutments. The reinforced earth walls would extend to also form the wingwalls supporting the highway embankment on approach to the structure. See Drg Nos TH/SBCC/230/HIG/118 and /125. The structure abutments and wingwalls would be built in isolation from Wanborough Road. Temporary closure of Wanborough Road would be necessary to install bridge deck beams, but this could be done at night to reduce impact on traffic. Construction traffic would be increased with an overbridge option in comparison to an at-grade crossing point, but it would limited to using Merlin Way to access the site, with no construction traffic permitted through Wanborough. Currently there is temporary a 7.5t weight restriction on Merlin Way between Covingham Drive and Kingfisher Drive. This temporary traffic regulation order is in place until December 2014. The alternative route takes vehicles along Covingham Drive – Dorcan Way – Kingfisher Drive. Kingfisher Drive is a traffic calmed residential area with a school. The weight restriction does not prevent vehicles from entering the zone for access, so use of the route by construction traffic in the Merlin Way area would need to be managed to minimise impact of the local area and residents.

13.3.8 Wanborough Road – Option A4 (underpass) The proposed structure for the underpass beneath Wanborough Road considered at feasibility stage is an in- situ reinforced concrete box unit with associated in-situ reinforced concrete wingwalls supporting the highway embankment on the approach to the structure – see Drg Nos TH/SBCC/230/HIG/117, /126 and /141 - /142.

The underpass would be built using a cut and cover method. It would be necessary to construct a temporary access road that would take traffic to the south side of the excavation and keep Wanborough Road open during the works. This would be built to the south-west side of Wanborough Road and be in the region of 300m long to go around the excavation. This would avoid traffic being diverted over the intermediate gas pressure main and provide more clearance around Wanborough House. To reduce the diversion road width, temporary traffic signals would be used to permit one way traffic flow and access into the works area. Construction traffic would be increased with an underpass option in comparison to an at-grade crossing point, but it would limited to using Merlin Way to access the site, with no construction traffic permitted through Wanborough. Currently there is temporary a 7.5t weight restriction on Merlin Way between Covingham Drive and Kingfisher Drive. This temporary traffic regulation order is in place until December 2014. The alternative route takes vehicles along Covingham Drive – Dorcan Way – Kingfisher Drive. Kingfisher Drive is a traffic calmed residential area with a school. The weight restriction does not prevent vehicles from entering the

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 13-3 SECTION 13 13 DELIVERY CONSIDERATIONS zone for access, so use of the route by construction traffic in the Merlin Way area would need to be managed to minimise impact of the local area and residents.

13.3.9 Liden Brook Structure The proposed structure for the crossing of Liden Brook is an in-situ concrete deck and pre-cast concrete beam superstructure supported on piled abutments. In-situ reinforced concrete wingwalls would be required to support the highway embankment on the approach to the structure. This would be a similar structure to that used in the Wanborough Road overbridge as shown on Drg Nos TH/SBCC/230/HIG/118 and /125.

The structure will be constructed in accordance with Environment Agency requirements and consents. The piled abutments on each side will need to be augered. Requirements for cofferdams would depend on the final structure size. Once abutments are in place, then the bridge deck beams can be installed.

Construction traffic would need to access the site off The Marsh for the south abutment and Wanborough Road for the north abutment.

13.3.10 Pack Hill widening The widening of Pack Hill near Commonhead roundabout (see Drg No TH/SBCC/230/HIG/150) could be carried out under a combination of one-way traffic, temporary signals and road closure depending on the proximity to the roundabout.

13.3.11 Public transport There are several bus routes (46A, 48A and 90) that use The Marsh. There would a period when The Marsh was closed between Pack Hill and Applegate House. Burycroft would not be served during the closures. These bus routes would require diverting via Church Road – Kite Hill - Rotten Row. This is an existing bus route, so would be suitable for this usage. This would increase bus flows along Kite Hill and Rotten Row by approximately 18 per day (9 in each direction).

13.3.12 Flood risk The EVSCR is to be built mainly outside of the 1 in 100 year flood risk area (Environment Agency Flood Zone 2), so would not be affected by flooding except in an extreme event. There will be a section of the EVSCR around Liden Brook that falls within the 1 in 100 year event flood risk zone. Modelling of the flood plain at preliminary and detailed design stages will have identified the extent of any flood mitigation works that need to be undertaken. The contractor will take this into consideration when constructing the works. This would require mitigation works being undertaken first and the bridge sub- structure being constructed within temporary works to prevent water ingress e.g. cofferdams. Details of the proposed drainage works and flood compensatory works are shown on Drg Nos TH/SBCC/230/DRA/200 - /203.

13.3.13 Private accesses Access to private properties will be maintained at all times, although it may be necessary to undertake diversions during certain phases of the construction works.

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There will be periods where construction works to provide new access points onto the EVSCR require short- term closure during excavations. The contractor would provide advanced notice and liaise with the landowner to arrange a convenient date and time to carry out the works. Where these extend over several days, then access can be maintained by temporary reinstatement and the like. Property A gains direct access to the A419 (opposite Wheatstone Road) – see Drg No TH/SBCC/230/HIG/112. This is the only point of access to the property. During construction, the contractor will need to undertake the works so as to maintain an access point for this property

13.3.14 Field accesses & farming New field paved accesses points will be provided on both sides of the EVSCR to maintain the link between fields severed. Typical layouts are shown on Drg No TH/SBCC/230/HIG/131. During construction, there will be periods of time when it will not be possible to access fields west of the new EVSCR due to earthworks and carriageway construction. Once the carriageway construction is complete, it may be possible to provide access over the link road to the fields. This would be at the consent of the contractor due to safety risks associated with permitting third parties access to the site.

13.3.15 NMUs There are a number of footpaths (Wanborough Central FP8, FP22, FP24 and FP25) that cross the EVSCR route – see Drg Nos TH/SBCC/230/HIG/110 - /114. It is likely that some periods of the construction phase it will be necessary to exclude pedestrians from the site for reasons of safety. This will require diversion of pedestrians around the works and these temporary diversions could be relatively lengthy.

13.3.16 Environmental considerations Construction works will need to consider the existing environment and ecology during site clearance, construction and landscaping. Further details are provided in Section 8 and are subject to the findings of the Phase 1 survey scheduled for April 2014.

13.4 Risk Register 13.4.1 Key Business Case Risks There are a number of risks associated with the strength of the Business Case, including: Robustness of the Eastern Villages traffic modelling (age of model, details of forecasting work, need to use a variable demand model) Lack of support for Business Case (political, stakeholder, public); Failure to develop a Business Case in line with funding allocations; and Failure to secure local financial contributions for the scheme. 13.4.2 Key Risks A summary of the key engineering risks is shown below Soft ground High water table Flood risk Canal protected route

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Ecological restrictions Utilities diversions Unidentified utilities during construction Unexploded bombs RSA & NMU Audits Unexpected protected species identified on site Unexpected archaeological issues discovered on site Unforeseen ground conditions including noxious weeds Spillage/pollution incidents on site Contaminated ground Asbestos found on site Noise pollution objections

13.4.3 Other Risks A number of risks have been identified which may be appropriate to a highway scheme of this nature, including:

Failure to secure land for corridor Failure to secure funding Failure to secure statutory orders including TROs Judicial review of processes evoked or other legal challenges Changes in design standards/legislation Adverse weather impact Optimism bias

13.5 Cost Estimates Cost estimates have been prepared for both recommended routes and the different options at Wanborough Road crossing point. Estimates include an Optimism Bias

TABLE 13-1 Eastern Villages Southern Connector Road estimated construction costs – With equestrian route widening

Option A1 Option A2 Option A3 Option A4 Wanborough Road Wanborough Road Wanborough Road Wanborough Road At grade cross roads At grade signals Overbridge Underpass Preliminaries £351,000 £351,000 £458,000 £408,000

EVSCR construction £6,183,000 £6,233,000 £10,255,000 £7,736,000

Pack Hill Widening £65,000 £65,000 £65,000 £65,000

Utilities £950,000 £950,000 £950,000 £950,000

Construction Estimate £7,549,000 £7,599,000 £11,728,000 £9,159,000

Design Fees £430,000 £435,000 £520,000 £520,000

13-6 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 13 13 DELIVERY CONSIDERATIONS

TABLE 13-1 Eastern Villages Southern Connector Road estimated construction costs – With equestrian route widening

Option A1 Option A2 Option A3 Option A4 Wanborough Road Wanborough Road Wanborough Road Wanborough Road At grade cross roads At grade signals Overbridge Underpass Scheme Cost £7,979,000 £8,034,000 £12,248,000 £9,679,000

Optimism bias (+44%)* £3,511,000 £3,535,000 £5,389,000 £4,259,000

Scheme total £11,490,000 £11,569,000 £17,637,000 £13,938,000

* Optimism bias based on Standard Civil Engineering Projects Capital expenditure upper limit

TABLE 13-2 Eastern Villages Southern Connector Road estimated construction costs – No equestrian route widening

Option A1 Option A2 Option A3 Option A4 Wanborough Road Wanborough Road Wanborough Road Wanborough Road At grade cross roads At grade signals Overbridge Underpass Preliminaries £341,000 £341,000 £449,000 £400,000

EVSCR construction £5,675,000 £5,725,000 £9,201,000 £7,191,000

Pack Hill Widening £65,000 £65,000 £65,000 £65,000

Utilities £950,000 £950,000 £950,000 £950,000

Construction Estimate £7,031,000 £7,081,000 £10,665,000 £8,606,000

Design Fees £421,000 £425,000 £516,000 £516,000

Scheme Cost £7,452,000 £7,506,000 £11,181,000 £9,122,000

Optimism bias (+44%)* £3,279,000 £3,302,000 £4,920,000 £4,014,000

Scheme total £10,731,000 £10,808,000 £16,101,000 £13,136,000

* Optimism bias based on Standard Civil Engineering Projects Capital expenditure upper limit

TABLE 13-3 Eastern Villages Southern Connector Road estimated construction costs – Additional cost for equestrian route widening

Scheme total Option A1 Option A2 Option A3 Option A4 Wanborough Road Wanborough Road Wanborough Road Wanborough Road (inc Optimism Bias) At grade cross roads At grade signals Overbridge Underpass With equestrian route £11,490,000 £11,569,000 £17,637,000 £13,938,000

Without equestrian route £10,731,000 £10,808,000 £16,101,000 £13,136,000

Additional cost for £759,000 £761,000 £1,536,000 £802,000 equestrian route

* Optimism bias based on Standard Civil Engineering Projects Capital expenditure upper limit

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Note these costs: exclude land costs for whole scheme, not just that in Swindon Borough Council ownership; exclude costs associated with preparation and implementation of orders, inquiries and the like; exclude mitigation and compensatory costs; exclude non-engineering costs, such as legal fees; exclude inflation; and exclude quantified risk assessment costs.

13-8 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 14 14 Preferred Route and Options

14.1 Eastern Villages Southern Connector Road summary This feasibility study for the EVSCR between Pack Hill and Wanborough Road has considered the following: horizontal alignments at various speeds (30mph to 60mph); review of existing and proposed speed limits; alternative crossing points at Wanborough Road – at-grade, overbridge and underpass; avoiding existing constraints such as properties and environmental assets; minimising the extent of the road within the Flood Risk Zone; mitigating loss of flood plain area; preparing a vertical alignment keeping the pavement construction above the 1 in 100 year flood level; preparing a vertical alignment so that it can drain by gravity using gullies (avoiding minimum gradients) and sustainable drainage systems (excepting the underpass); existing and future requirements for pedestrians, cyclist and equestrians; maintaining property access and avoiding severance; maintaining public transport links; reducing works to utilities where possible; assessing the buildability of the scheme and issues such as access and routeing of construction traffic producing a more sympathetic earthworks layout in keeping with the surrounding area

14.2 Preferred Eastern Villages Southern Connector Road Alignment Option The alignments were reduced during the study to Options A and B. Option A is the preferred road alignment as: it creates an alignment that keeps traffic speeds down as they approach the development and Wanborough Road; will be more in keeping with the future Eastern Villages development reduces the extent of the EVSCR within the Flood Risk Zone; avoids taking of property (except for a stable block); avoids environmentally sensitive areas; maintains access for properties;

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 14-1 SECTION 14 14 PREFERRED ROUTE AND OPTIONS 14.3 Preferred Wanborough Road Crossing Option The crossing of Wanborough Road by the EVSCR reduced to two from six. The two preferred crossing options are considered below for their benefits, disadvantages and scheme cost.

TABLE 14-1 Layout Option Summary

Option A4 underpass Option A2 signalised crossing point Benefits Disadvantages Benefits Disadvantages less land take than more land required reduce the costs will need monitoring overbridge compared to signalised associated with the and enforcement crossroads work less visual intrusion signals not in keeping than overbridge increased structure less land take than with local surroundings extent overbridge or reduced costs residents concern of underpass compared to lighting of underpass monitoring and abuse overbridge required for be less disruptive to of crossing point by pedestrians users of Wanborough vehicles guarantees separation Road of traffic from safety barrier required Wanborough Road less visually intrusion increased cost over than an overbridge or Wanborough Road will signalised crossroads underpass have similar more construction appearance to existing have lower noise disruption to pollution than an pedestrians and cyclists Wanborough Road overbridge can be separated from compared to signalised Wanborough Road crossing point be safer than an uncontrolled cross road likely to be preferred by increased construction arrangement residents compared to traffic compared to overbridge underpass reduced construction traffic compared to increased maintenance and potential for underpass flooding if pumping no safety barrier station fails required increased risk to gas no risk of flooding mains during

construction reduced risk to gas mains during construction

Scheme cost (with equestrian Scheme cost (with equestrian £13,938,000 £11,569,000 route) route)

Scheme cost (with no Scheme cost (with no £13,136,000 £10,808,000 equestrian route) equestrian route)

14-2 EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX SECTION 14 14 PREFERRED ROUTE AND OPTIONS

14.4 Summary of EVSCR Options

It is recommended that subject to funding and land availability, that the options be considered in the order shown in Table 14-2 below:

TABLE 14-2 Eastern Villages Southern Connector Road Option Summary Ref Option Scheme Cost

EVCSR-1 Option A4 Underpass (with equestrian widening) £13,938,000

Option A4 Underpass (without equestrian EVSCR-2 £13,136,000 widening)

Option A2 signalised crossroads (with equestrian EVSCR-3 £11,569,000 widening)

Option A2 signalised crossroads (without EVSCR-4 £10,808,000 equestrian widening)

EVSCR FEASIBILITY STUDY V1 0 - NO PHOTOS.DOCX 14-3

Appendix A - Site photographs

Appendix B – Geotechnical Assessment Report

Appendix C – Environmental Appraisal Report

Appendix C – Drawings

Drawing No Revision Title TH/SBCC/230/HIG/100 - Location Plan TH/SBCC/230/HIG/101 - Land Ownership Plan TH/SBCC/230/HIG/102 - Existing Constraints TH/SBCC/230/HIG/103 - Existing Utilities TH/SBCC/230/HIG/104 - Optioneering 30mph Highway Alignments TH/SBCC/230/HIG/105 - Optioneering 40mph Highway Alignments TH/SBCC/230/HIG/106 - Optioneering 50mph Highway Alignments TH/SBCC/230/HIG/107 - Optioneering 60mph Highway Alignments TH/SBCC/230/HIG/108 - Preferred Highway Alignments TH/SBCC/230/HIG/109 - New Speed Limit Extents TH/SBCC/230/HIG/110 - General Arrangement Sheet 1 of 5 TH/SBCC/230/HIG/111 - General Arrangement Sheet 2 of 5 TH/SBCC/230/HIG/112 - General Arrangement Sheet 3 of 5 TH/SBCC/230/HIG/113 - General Arrangement Sheet 4 of 5 TH/SBCC/230/HIG/114 - General Arrangement Sheet 5 of 5 TH/SBCC/230/HIG/115 - Wanborough Road Option A1 At Grade Crossing Point TH/SBCC/230/HIG/116 - Wanborough Road Option A2 Signalised At Grade Crossing Point TH/SBCC/230/HIG/117 - Wanborough Road Option A4 Underpass TH/SBCC/230/HIG/118 - Wanborough Road Option A3 Overbridge TH/SBCC/230/HIG/119 - Proposed EVSCR Centreline Levels TH/SBCC/230/HIG/120 - Longsection Sheet 1 of 5 TH/SBCC/230/HIG/121 - Longsection Sheet 2 of 5 TH/SBCC/230/HIG/122 - Longsection Sheet 3 of 5 TH/SBCC/230/HIG/123 - Longsection Sheet 4 of 5 TH/SBCC/230/HIG/124 - Longsection Sheet 5 of 5 TH/SBCC/230/HIG/125 - Longsection Sheet 5 of 5 Overbridge Option A3 TH/SBCC/230/HIG/126 - Longsection Sheet 5 of 5 Underpass Option A4 TH/SBCC/230/HIG/130 - Standard Details Sheet 1 of 2 TH/SBCC/230/HIG/131 - Standard Details Sheet 2 of 2 TH/SBCC/230/HIG/140 - Typical Cross-Sections Sheet 1 of 4 TH/SBCC/230/HIG/141 - Typical Cross-Sections Sheet 2 of 4 TH/SBCC/230/HIG/142 - Typical Cross-Sections Sheet 3 of 4 TH/SBCC/230/HIG/143 - Typical Cross-Sections Sheet 4 of 4 TH/SBCC/230/HIG/150 - Pack Hill Widening TH/SBCC/230/HIG/151 - Footpath 22 Diversion TH/SBCC/230/HIG/200 - Proposed Layout - Drainage Proposal - Option 1 (Wanborough Road Crossing at TH/SBCC/230/HIG/201 Grade) - Drainage Proposal - Option 2 (Wanborough Road Crossing - TH/SBCC/230/HIG/202 Bridge) - Drainage Proposal - Option 3 (Wanborough Road Crossing - TH/SBCC/230/HIG/203 Tunnel)