Northamptonshire County Council NORTH WEST RELIEF ROAD Environmental Statement Addendum Volume II: Main Written Statement

JUNE 2020 PUBLIC

Northamptonshire County Council

NORTHAMPTON NORTH-WEST RELIEF ROAD Addendum to the Environmental Statement Volume II: Written Statement

TYPE OF DOCUMENT (VERSION) PUBLIC

PROJECT NO. 70021598 PLANNING REFERENCE NO: 19/00045/CCDFUL

DATE: MAY 2020

PUBLIC

Northamptonshire County Council

NORTHAMPTON NORTH-WEST RELIEF ROAD Addendum to the Environmental Statement Volume II: Written Statement

WSP 1 Capital Quarter Tyndall Street Cardiff CF10 4BZ Phone: +44 2920 769 200

WSP.com

PUBLIC

CONTENTS

1 INTRODUCTION 1

2 CHANGES TO THE DESCRIPTION OF THE PROPOSED SCHEME 4

3 APPROACH TO THE EIA 12

4 AIR QUALITY 30

5 CLIMATE CHANGE 82

6 LANDSCAPE AND VISUAL 93

7 NOISE AND VIBRATION 100

8 ROAD DRAINAGE AND THE WATER ENVIRONMENT 159

9 SUMMARY OF EFFECTS 197

NORTHAMPTON NORTH-WEST RELIEF ROAD PUBLIC | WSP Project No.: 70021598 | Our Ref No.: 19/00045/CCDFUL May 2020 Northamptonshire County Council

1 INTRODUCTION

1.1 BACKGROUND 1.1.1. Northamptonshire County Council (referred to as ‘the Applicant’) is seeking to obtain detailed planning permission for the Northampton North-West Relief Road (referred to as the 'Proposed Scheme’), located on land approximately 1.2km south-east of Church Brampton and immediately east of the Brampton Heath Golf Centre. 1.1.2. The Proposed Scheme will connect the A5199 Welford Road, via Sandy Lane, with a proposed junction located adjacent to Grange Farm, which will provide access to the land allocated for the proposed Dallington Grange development. The Proposed Scheme forms part of a wider strategy to complete the ring road around the northern sector of Northampton that will ultimately connect the A4500 Weedon Road and M1 Motorway Junction 16 to the west, with the A43 Road and Kettering to the north. Please refer to Figure 2.1: General Arrangement Design (Volume IV of the Environmental Statement Addendum (ESA)). 1.1.3. The Applicant submitted a planning application for the Proposed Scheme in June 2019 (Planning application reference: 19/00045/CCDFUL). The proposed planning application is seeking permission for: The construction of new roads on land south of the A5199 Northampton Road between the Brampton Heath Golf Centre and the , including two new roundabouts and links bridging over the River Nene to Brampton Lane and over the Northampton Loop of the West Coast Main Line to connect with the Dallington Grange development. 1.1.4. The Proposed Scheme falls under Schedule 2 of the Town and Country Planning (Environmental Impact Assessment) Regulations 2017 (Ref. 1-1) (hereafter referred to as the ‘EIA Regulations’). Therefore, an Environmental Statement (ES) was prepared and submitted in support of the planning application in June 2019 (hereafter referred to as the ‘2019 ES’). 1.1.5. The planning application and supporting documents, including the 2019 ES, have been subject to consultation with statutory bodies such as Natural (NE), the Environment Agency (EA), Historic England, internal officers at Northamptonshire County Council, District Council, and Northampton Borough Council. In addition, parish councils, members of the public and other organisations have been provided with the opportunity to comment on the planning application as part of the determination process. 1.1.6. Since submission of the 2019 ES, changes to the Proposed Scheme design and traffic flow information have occurred. In line with Regulation 25 of the EIA Regulations, and in order to satisfy the requirements of Regulation 18(2) and (3), the project team have prepared further information to supplement the 2019 ES based on these changes. This “further information” is described, assessed, and reported as part of an Environmental Statement Addendum (ESA). 1.1.7. WSP has been commissioned by the Applicant to carry out updates to the EIA taking account of the updated design and traffic flow information in support of the planning application and prepare the ESA which sits alongside the 2019 ES. This work has incorporated information from further consultation with the Northamptonshire County Council Planning Department and other statutory consultees as part of the EIA Scoping process.

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1.2 PURPOSE AND STRUCTURE OF THE ENVIRONMENTAL STATEMENT ADDENDUM (ESA) 1.2.1. The focus of the ESA has been to identify any environmental impacts which are likely to give rise to new or different significant adverse effects as a result of the changes to the Proposed Scheme design and the updated information pertaining to the Proposed Scheme. 1.2.2. The changes to the Proposed Scheme design are presented in Section 2.0 of this document and any updated and new environmental information is presented in Section 3.0. Readers should note that the ESA is not a duplication of the 2019 ES and should be read in conjunction with the 2019 ES. WSP have consulted with the NCC Planning Department and Statutory Consultees on the approach, methodology, and scope of the ESA to ensure that it is robust and proportionate. Further detail is provided in Section 3.0 and Appendix 3.6: EIA Scoping Addendum Report (Volume III of the ESA). 1.2.3. Following the same structure as the 2019 ES, the ESA is made up of four volumes:  Volume I: Non-Technical Summary;  Volume II: Written Statement;  Volume III: Technical Appendices; and  Volume IV: Supporting Figures and Plans. 1.3 LEGAL FRAMEWORK FOR THE ES AND ESA 1.3.1. The EIA Regulations implement the requirements of EU Directive 2014/52/EU and require that prior to consent being granted, for certain types of development, an EIA must be undertaken. The EIA Regulations set out the types of development which must always be subject to an EIA (Schedule 1 development) and other developments which may require an assessment if they give rise to likely significant effects (Schedule 2 development). 1.3.2. The Proposed Scheme falls under Schedule 2 of the EIA Regulations. It is the responsibility of the local planning authority to determine the need for an EIA through the evaluation of the sensitivity of the Site and surrounding area, and whether the Proposed Scheme has the potential to result in likely significant effects by its characteristics, location and nature of the effects (in accordance with Regulation 5 of the EIA Regulations). 1.3.3. An EIA Screening Request was submitted to the Northamptonshire County Council (NCC) Planning Department in January 2018 (please refer to Appendix 5.1: EIA Screening Request - Volume III of the 2019 ES). A response was received on 22 February 2018, within which NCC determined that the Proposed Scheme will require an EIA and advised on the topic areas that should be covered as part of the ES (please refer to Appendix 5.2: EIA Screening Opinion - Volume III of the 2019 ES). 1.3.4. An EIA Scoping Report was submitted to NCC Planning Department on 07 August 2018 together with a formal request for an EIA Scoping Opinion in accordance with Regulation 15 of the EIA Regulations ((please refer to Appendix 5.3: EIA Scoping Report - Volume III of the 2019 ES). A formal Scoping Opinion was subsequently received from NCC Planning Department on 18 September 2018 (please refer to Appendix 5.4: EIA Scoping Opinion - Volume III of the 2019 ES). 1.3.5. The findings of the EIA are presented in the 2019 ES which was prepared in accordance with the EIA Regulations as well as planning practice guidance (Ref 1-2). The ES was submitted to the NCC Planning Department in June 2019.

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1.3.6. Following the process of identifying that the Applicant would need to submit “further information” to supplement the ES, an EIA Scoping Addendum Report was submitted to NNC Planning Department on 20 April 2020, please refer to Appendix 3.6: EIA Scoping Addendum Report (Volume III of the ESA). 1.3.7. A formal Scoping Opinion on the content of the ESA was subsequently received from NCC Planning Department on 02 June 2020, please refer to Appendix 3.7: EIA Scoping Addendum Opinion (Volume III of the ESA). 1.4 THE PROJECT TEAM 1.4.1. WSP has been commissioned by the Applicant to carry out the EIA in support of the planning application. This has incorporated technical input from environmental and technical specialists. 1.4.2. In line with Regulation 18(5)(a) – (b) of the EIA Regulations, the 2019 ES, ESA and technical assessments which inform both documents have been undertaken by a suitably qualified project team. 1.4.3. WSP is responsible for the coordination, compilation and procedural review of the ES. WSP is registered under the EIA Quality Mark operated by the Institute of Environmental Management and Assessment (IEMA) which recognises our commitment to excellence in EIA activities. WSP was one of the original eight pilot organisations in the UK that trialled the process in 2011 and developed the EIA Quality Mark scheme from the former Corporate Registered Assessor process. We have continued to maintain our EIA Quality Mark registration, following annual examination by IEMA in relation to our ongoing products, staff, innovation and promotion of EIA within the industry. WSP has and continues to support and lead nationally recognised guidance for EIA in the UK. WSP has developed and applies an in-house set of processes, procedures and guidance for EIA based on sound project management principles. 1.5 REFERENCES  Ref. 1-1: Town and Country Planning (Environmental Impact Assessment) Regulations 2017. Statutory Instrument 2017 No. 571.  Ref. 1-2: Planning Practice Guidance (PPG) Online Tool. [Online] accessed via https://www.gov.uk/guidance/environmental-impact-assessment, May 2020.

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2 CHANGES TO THE DESCRIPTION OF THE PROPOSED SCHEME

2.1 INTRODUCTION 2.1.1. This chapter provides a description of the design changes to the Proposed Scheme and should be read in conjunction with Chapter 3: Description of the Proposed Scheme from the 2019 ES which includes further detail on how the Proposed Scheme would be constructed, alongside the assumptions used for the basis of assessment where this information is subject to confirmation. The information presented in this chapter is an evolution of the design description provided in the 2019 ES. 2.1.2. Some of the design changes presented in this chapter are different to the design changes presented in the EIA Scoping Addendum Report (please refer to Appendix 3.6: EIA Scoping Addendum Report (Volume III of the ESA)). This is due to on-going consultation and design development. The main differences between the design changes presented in the EIA Scoping Addendum Report and this Chapter are as follows:  Flood Management Infrastructure (Flood Replacement Storage Areas): The EIA Scoping Addendum Report outlined that, as a result of design development, Flood Storage Replacement Areas A, B, and C have been removed from the design of the Proposed Scheme. However, following further design development and consideration of the potential ecological benefits that a flood storage replacement area can bring, a decision has been made to preserve a singular flood storage replacement area which covers the same footprint and will be known as Flood Storage Replacement Area A. Further detail is provided in Section 2.2.  Flood Management Infrastructure (Drainage Channel Diversion): The Proposed Scheme includes a diverted drainage channel to support the mitigation of downstream flood risk. Further detail is provided in Section 2.2.  Inclusion of Accommodation Access provisions: The Proposed Scheme now includes four accommodation access points to provide landowners with access to land parcels that have been severed by the Main Carriageway and Causeway but will continue to be used for agricultural purposes. Further detail is provided in Section 2.2.  Inclusion of Maintenance Access provisions: The Proposed Scheme now includes three maintenance access points to allow the general day-to-day upkeep of certain design features, including bridges and balancing ponds. Further detail is provided in Section 2.2. 2.2 CHANGES TO THE OPERATIONAL DESIGN INTRODUCTION 2.2.1. The following section describes the main design changes to permanent features of the Proposed Scheme, this includes any changes to the proposed embedded (‘primary’) mitigation measures that have been identified. This section should be read in conjunction with Chapter 3: Description of the Proposed Scheme (Volume II of the 2019 ES) and Figure 2.1 – General Arrangement Design (Volume IV of the ESA) which presents the most up to date design. 2.2.2. The following sections outline the key changes to each component. Please also refer to Figure 2.2 – Changes to General Arrangement Design (Volume IV of the ESA) which has been prepared to highlight the main changes to the Proposed Scheme.

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2.2.3. Readers should note that where key features are associated with more than one component of the Proposed Scheme, they are described within the section they are first associated with. Where reference is made to the Proposed Scheme, this includes all components collectively. CHANGES TO PROPOSED ROUNDABOUTS Proposed Sandy Lane Roundabout 2.2.4. As presented in Chapter 3: Description of the Proposed Scheme (Volume II of the ES), the proposed Sandy Lane Roundabout will be located approximately 10m west of the River Nene and 20m south of the existing Sandy Lane Junction which connects into the A5199 Northampton Road. The proposed roundabout will directly replace the existing junction arrangements that connect Sandy Lane with the A5199 Northampton Road. 2.2.5. The design of the proposed Sandy Lane Roundabout, as presented in Figure 2.1 – General Arrangement Design (Volume IV of the ESA) has been amended to accommodate greater highway capacity. The main changes to the roundabout will be as follows:  Realignment to all four arms proposed for the roundabout. The northern arm, connecting into the A5199 Northampton Road, will see the largest realignment, moving approximately 40m east;  Adjustments to the layout of the roundabout to fit with the realignment of the roundabout arms; and  Adjustments to the embankments and road verges associated with the roundabout. Proposed Brampton Lane Roundabout 2.2.6. As presented in Chapter 3: Description of the Proposed Scheme (Volume II of the ES), the proposed Brampton Lane Roundabout will be located approximately 10m south-west of the Windhover Public House. The proposed roundabout will directly replace the existing junction arrangements that connect Brampton Lane with the A5199 Northampton Road / A5199 Welford Road. 2.2.7. The design of the proposed Brampton Lane Roundabout, as presented in Figure 2.1 – General Arrangement (Volume IV of the ESA) has been amended to accommodate greater highway capacity. The main changes to the roundabout will be as follows:  Realignment to the proposed southern and western arms of the roundabout;  Adjustments to the footway/cycleway provisions on the western, northern and eastern arms of the roundabout; and  Adjustments to the embankments and road verges associated with the roundabout. CHANGES TO DRAINAGE INFRASTRUCTURE Highway Balancing Ponds 2.2.8. As presented in Chapter 3: Description of the Proposed Scheme (Volume II of the ES), a highway balancing pond, measuring approximately 70m by 40m was proposed north of the Causeway, 100m west of The Windhover Public House. 2.2.9. As a result of design development, the proposed highway balancing pond has been relocated south of the Causeway. The highway balancing pond will measure approximately 60m by 40m and will be located 110m south-west of The Windhover Public House. Please refer to Figure 2.1 – General Arrangement (Volume IV of the ESA).

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CHANGES TO FLOOD MANAGEMENT INFRASTRUCTURE Introduction 2.2.10. The development of the flood mitigation proposals in the 2019 ES had assumed ground conditions at the Site would be suitable to construct three connected flood storage replacement areas (A, B, and C) to the north of the Milton Keynes to Rugby railway line. Please refer to Figure 3.1: General Arrangement Design (Volume IV of the 2019 ES). The flood storage replacement areas were designed to mitigate any floodplain lost to the Proposed Scheme. 2.2.11. Since submission of the 2019 ES, further design work has been undertaken to understand the ground conditions at the Site. High groundwater levels in the southern part of the Site mean any flood storage replacement areas immediately north of the Milton Keynes to Rugby railway line will need shallow side slopes. In addition, a larger buffer zone will be required between the flood storage replacement areas and the Milton Keynes to Rugby railway line to prevent changes in groundwater levels impacting the railway embankment. 2.2.12. The requirement to redesign the flood storage replacement areas mean that the potential capacity of the flood storage replacement areas (i.e. ability to hold water in a flood event) has been reduced. Therefore, the flood storage replacement areas north of the Milton Keynes to Rugby railway line have been simplified to maximise the available volume in this area, and, combined with a flood mitigation bund, provide additional attenuation capacity to mitigate any floodplain lost to the Proposed Scheme. Flood Storage Replacement Areas 2.2.13. As presented in Chapter 3: Description of the Proposed Scheme (Volume II of the ES), four flood compensation storage areas were included as part of the Proposed Scheme to replace part of the River Nene floodplain that will be lost to the construction of the Main Carriageway. 2.2.14. As a result of design development, Flood Storage Replacement Areas A, B, and C have been replaced with a singular flood storage replacement area, known as Flood Storage Replacement Area A. Flood Storage Replacement Area A measures, approximately 3.0ha in size and up to 2m below existing ground level. 2.2.15. As a result of this design change, Flood Storage Replacement Area D, as presented in Chapter 3: Description of the Proposed Scheme (Volume II of the ES), has been renamed Flood Storage Replacement Area B. Please refer to Figure 2.1 – General Arrangement (Volume IV of the ESA). Flood Mitigation Embankment 2.2.16. The Proposed Scheme has been developed to include a raised earth embankment measuring approximately 280m in length, up to 2m above existing ground level, and up to 20m in width. The embankment will bisect the floodplain downstream of the River Nene and Brampton Brook confluence, but upstream of the proposed railway overbridge. 2.2.17. The embankment will tie into the raised ground associated with the Milton Keynes to Rugby railway line embankment and run perpendicular to the River Nene flow direction. The purpose of the earth embankment is to reduce the width of the floodplain and hence flows downstream. Please refer to Figure 2.1 – General Arrangement (Volume IV of the ESA).

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Channel Diversion 2.2.18. The Proposed Scheme has been developed to include a drainage channel diversion away from the footprint of the Flood Mitigation Embankment. The channel diversion, which has adopted a trapezoidal shape, measures approximately 165m in length, is up to 10m in width, and up to 2m deep below existing ground levels. 2.2.19. The channel diversion has been included to allow the Flood Mitigation Embankment to be constructed as an uninterrupted structure and so will support the mitigation of downstream flood risk. The channel diversion will complement existing minor watercourses and channels in the vicinity of the area. Please refer to Figure 2.1 – General Arrangement (Volume IV of the ESA). CHANGES TO ACCESS PROVISIONS Accommodation Access 2.2.20. Chapter 3: Description of the Proposed Scheme (Volume II of the ES) outlined that following submission of the 2019 ES, liaison with landowners, business owners and farmers would be ongoing to ensure access to agricultural land is maintained, where appropriate, and appropriate permanent access arrangements would be built into the accommodation works designs. 2.2.21. The Proposed Scheme has been developed to include accommodation access points along the Main Carriageway and Causeway to maintain access to parcels of agricultural land that will remain in operation. 2.2.22. The following accommodation access provisions have been identified with stakeholders and are included as part of the Proposed Scheme:  Accommodation access provisions to the west and east of the Main Carriageway, approximately 160m south of the proposed Sandy Lane roundabout;  Accommodation access provision to the south of Sandy Lane, approximately 60m west of proposed Sandy Lane roundabout; and  Accommodation access provision to the south of the Causeway, approximately 40m west of proposed Brampton Lane roundabout. 2.2.23. Please refer to Figure 2.1 – General Arrangement (Volume IV of the ESA). Maintenance Access 2.2.24. The Proposed Scheme has been developed to include maintenance access points to allow the general day-to-day upkeep of certain design features during the operation of the Proposed Scheme:  Maintenance access provision to serve the railway overbridge, the parking area is located approximately 15m east of the railway overbridge;  Maintenance access provision to serve the two highway balancing ponds east of the Main Carriageway, the parking area is located approximately 270m north of the railway overbridge; and  Maintenance access provision to serve the River Nene Crossing. The access track branches off the northern arm of the proposed Brampton Lane Roundabout and runs adjacent to the northern edge of the Causeway. The parking area is located approximately 15m north-east of the River Nene Crossing. 2.2.25. Please refer to Figure 2.1 – General Arrangement (Volume IV of the ESA).

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CHANGES TO MITIGATION 2.2.26. Chapter 3: Description of the Proposed Scheme (Volume II of the ES), specifically paragraph 3.2.28- 3.2.29 and Table 3-1, outlined the ‘primary’ environmental mitigation that had been developed and designed to form part of the Proposed Scheme. The mitigation measures proposed were the product of an iterative design process, with the overall objective of avoiding and reducing significant adverse environmental effects. The mitigation measures proposed in the 2019 ES are still relevant and form the basis of the ESA. 2.2.27. Since the 2019 ES submission, the changes to the Proposed Scheme design, as outlined above, has resulted in a requirement to amend some of the mitigation measures identified in Table 3-1 (Volume II of the 2019 ES) and incorporate some additional measures as part of the Proposed Scheme. 2.2.28. Table 2-1 outlines the mitigation measures which have been amended or included since the 2019 ES submission. As set out in Chapter 3: Approach to EIA (Volume II of the ESA), the initial assessments of magnitude of impact and potential significance of effects reported within the Technical Chapters of this ESA (Technical Chapters 4-8) take account of the mitigation measures detailed in Table 3-1 (Volume II of the 2019 ES) and Table 2-1 (overleaf). Where secondary or tertiary mitigation measures are required, further detail is provided within Technical Chapters 4-8.

Table 2-1: Primary Mitigation – Amended or additional since 2019 ES submission

Mitigation 2019 ES: Description / Environmental 2020 ESA: Description / Measure Objectives Environmental Objectives

Flood Located east of the Main Carriageway and Flood Replacement Storage Area A will Replacement north of the Rugby to Milton Keynes railway collect floodplain flows that come out of Storage Area A line, Flood Replacement Storage Area A will the bank to the north of Brampton replace part of the floodplain that will be lost Brook. These will be diverted along the to the construction of the Main Carriageway. eastern face of the Main Carriageway, Flood Replacement Storage Area A will via a flood flow channel into the storage collect floodplain flows that come out of the area. bank to the north of Brampton Brook. These The preliminary design includes the will be diverted along the eastern face of the creation of marginal planting around the Main Carriageway, via a flood flow channel storage area, this will include floodplain and into the storage area. grazing marsh and reed beds, and The preliminary design includes the creation marshy grassland at the base of the of marginal planting around the storage area, storage areas. this will include floodplain grazing marsh and reed beds.

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Mitigation 2019 ES: Description / Environmental 2020 ESA: Description / Measure Objectives Environmental Objectives

Flood Located east of the Main Carriageway and Flood Replacement Storage Area A will replacement north of the Rugby to Milton Keynes railway collect floodplain flows that come out of storage area line, Flood Replacement Storage Areas B the bank to the north of Brampton B/C and C will replace part of the floodplain that Brook. These will be diverted along the will be lost to the construction of the Main eastern face of the Main Carriageway, Carriageway. via a flood flow channel into the storage Flood Replacement Storage Areas B and C area. will collect floodplain flows from the River The preliminary design includes the Nene immediately adjacent to the basin. creation of marginal planting around the The preliminary design includes the creation storage area, this will include floodplain of marginal planting around the storage grazing marsh and reed beds, and areas, this will include floodplain grazing marshy grassland at the base of the marsh and reed beds, and marshy grassland storage areas. at the base of the storage areas.

Flood Mitigation Not included in the 2019 ES. The embankment will bisect the Embankment floodplain downstream of the River Nene and Brampton Brook confluence, but upstream of the proposed railway overbridge. The embankment will reduce the width of the floodplain and hence flows downstream of the Proposed Scheme.

Channel Not included in the 2019 ES. The increased length of drainage Diversion channel will provide opportunities for ecological enhancement with new habitats as well as improved foraging routes and habitat connectivity.

Accommodation Not included in the 2019 ES. The accommodation access provision Access will reduce severance impacts on the Provisions operational use of agricultural land.

2.3 CONSTRUCTION DESIGN INTRODUCTION 2.3.1. The construction design information presented in Chapter 3: Description of the Proposed Scheme (Volume II of the ES) remains valid and has informed the basis of the ESA. 2.3.2. Chapter 3: Description of the Proposed Scheme (Volume II of the ES), specifically Section 3.3.33, referred to a programme of advanced works that would be completed in advance of the construction works. This section provides an update on those activities. 2.3.3. Chapter 3: Description of the Proposed Scheme (Volume II of the ES), specifically Section 3.3.36 and Table 3-4, referred to an indicative construction programme. This section provides an update on the construction programme based on the completion of advanced works and the length of time that has passed since the June 2019 planning submission.

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ADVANCED WORKS 2.3.4. The 2019 ES outlined scheduled advanced works which were programmed to be delivered in advance of the construction programme to inform the detailed design process. 2.3.5. Table 2-2 outlines the scheduled advanced works and indicates the progression of works since the 2019 ES submission.

Table 2-2: Update on scheduled Advanced Works following 2019 ES submission

Schedule of Advanced Works presented in the ESA 2020 2019 ES

Ecological surveys: A full suite of ecological surveys, A full suite of ecological surveys was completed in focussing on terrestrial, ornithological, and aquatic 2019. Updated baseline reports were provided to species, have been programmed from April 2019 to NCC Planning Department in September 2019, November 2019. including; Breeding Bird Survey Report, Hedgerow Report, Badger Report, Barn Owl Report, Great Crested Newt Report, Otter and Water Vole Report, and Reptile Report. In addition, ecological surveys have been completed for; kingfisher, bats, and aquatic species in 2019. Updated and new baseline reports have been included as part of this ESA. Please refer to Appendix 3.3 – 3.7 (Volume III of the ESA).

Geotechnical investigations: Geotechnical Site investigation works to inform the detailed design Investigation works have been programmed in process and earthworks strategy have been summer 2019 across the Site to inform the detailed completed across the site. Geotechnical design and earthworks strategy investigations of ground conditions were completed in 2018 and 2019.

Archaeological Trial Trenching: A programme trial In 2019, WSP commissioned Oxford Archaeology to trenching surveys will commence in summer 2019. undertake archaeological intrusive works across the The survey work will inform the mitigation strategy Site. The works were commissioned to enhance the for unknown buried archaeology across the Site and understanding of the underlying archaeological inform the detailed design. potential across the Site and to incorporate best practice measures and mitigation in order to preserve significant archaeological remains. The scope of works was agreed with NCC in advance through a Written Scheme of Investigation (WSI). The trial trenching evaluation comprised 123 trenches ranging from 30m by 1.6m to 50m by 2.2m. An Archaeological Evaluation Report was submitted to NCC in October 2019.

INDICATIVE CONSTRUCTION PROGRAMME 2.3.6. An updated indicative construction programme illustrating indicative periods for each of the core construction activities outlined is provided in Table 2-3 (overleaf). Please note, the only changes to the activity programme relate to pre-construction activities, these are highlighted in blue in Table 2-3 (overleaf).

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Table 2-3: Updated Indicative construction programme.

Activity Programme

Advance works Completed

Site clearance Q3 2020

Site mobilisation Q3 2020

Construction of Railway Overbridge Q3 2020 – Q1 2021

Construction of South Embankment Q3 2020 – Q4 2020

Construction of Sandy Lane Roundabout Q3 2020 – Q1 2021

Construction of River Nene Crossing and Carriageway (Sandy Lane Roundabout to Q3 2020 – Q1 2021 Brampton Lane Roundabout)

Construction of Brampton Lane Roundabout – Phase 1 Q3 2020 – Q4 2020

Construction of Brampton Lane Roundabout – Phase 2 Q4 2020 – Q1 2021

Construction of North Embankment Q3 2020 – Q3 2021

Construction of Carriageway (Sandy Lane Roundabout to Railway Overbridge) Q4 2020 – Q3 2021

Construction of Carriageway (Railway Overbridge to Dallington Grange Roundabout) Q2 2021 – Q3 2021

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3 APPROACH TO THE EIA

3.1 INTRODUCTION 3.1.1. Chapter 5: Approach to EIA (Volume II of the 2019 ES) outlined the approach to the EIA. This included:  Objectives and overall strategy for the EIA;  Approach to EIA Screening and EIA Scoping;  Approach to consultation (technical and community);  Approach to the assessment of the Proposed Scheme; and  Approach to the cumulative assessment. 3.1.2. The approach and methodology outlined in Chapter 5: Approach to EIA (Volume II of the 2019 ES) remains valid and should be read in conjunction with this chapter. This chapter focuses on the following elements:  Summary of the assessment criteria and determination of significance;  Summary of any updates to the baseline conditions, including new environmental information which has become available since submission of the 2019 ES and informed the EIA;  The process of scoping the technical approach and content of the ESA, and, in particular, the process of on-going scoping since submission of the EIA Scoping Addendum Report;  The updated approach to the cumulative assessment; and  Summary of updates to supporting assessment work. 3.2 ASSESSMENT CRITERIA 3.2.1. The classification of each effect identified within the 2019 ES and ESA has been assessed based on the magnitude of impact (or change) due to the Proposed Scheme and the value / sensitivity / importance of the affected receptor. Determining the classification of effects has been undertaken using professional judgement (assumptions and value systems) that underpin the attribution of significance. 3.2.2. Each effect has been assessed against the value/sensitivity/importance of the receptor and the magnitude of impact, as shown in Table 3.1 (overleaf). Where a choice of effect classification is available e.g. moderate or large, the most appropriate effect classification has been chosen based on judgement of the assessor. In general, effects of moderate or above are considered significant. 3.2.3. The classification of residual effects has been assessed regarding the extent to which secondary mitigation measures will avoid, prevent, reduce or, if possible, offset adverse effects or enhance beneficial effects. 3.2.4. The assessment of likely effects for each of the technical topics relevant to the ESA are presented in Technical Chapters 4 – 8 and have considered appropriate criteria to determine if the likely effects are significant. Wherever possible and appropriate, the effects have been assessed quantitatively. 3.2.5. Where topic specific methodology deviates from this approach, for example, because of following topic specific guidance, this is set out in the methodology section of the Technical Chapter. Tables summarising the likely significant effects associated with each technical topic area, required mitigation measures, and residual effects are provided at the end of each Technical Chapter.

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Table 3-1: Matrix for Classifying Effects Magnitude of impact (degree of change) No change Negligible Minor Moderate Major Moderate or Large or Very High Neutral Slight Very Large Large Very Large Value Slight or Moderate or Large or High Neutral Slight (sensitivity Moderate Large Very Large / Neutral or Moderate or Medium Neutral Slight Moderate importance) Slight Large Neutral or Neutral or Slight or Low Neutral Slight Slight Slight Moderate Neutral or Neutral or Negligible Neutral Neutral Slight Slight Slight 3.3 BASELINE CONDITIONS EXISTING BASELINE 3.3.1. Baseline information (environmental characteristics and conditions) to inform the 2019 ES was collated based upon surveys undertaken and desk-based information available at the time of the assessment. Any limitations to establishing the baseline were described in Technical Chapters 6 – 15 (Volume II of the ES). 3.3.2. A summary of the Site conditions and surrounding environs was provided in Chapter 2: The Existing Site (Volume II of the 2019 ES). The Site is defined as the area of land considered suitable for development of the Proposed Scheme and is identified in Figure 1.1: Site Location Plan (Volume IV of the 2019 ES) and Figure 1.2: Aerial View of the Site (Volume IV of the 2019 ES). The Site boundary comprises an area of approximately 66 hectares (ha) and is roughly defined by the A5199 Welford Road and Sandy Lane to the north, the Brampton Heath Golf Centre and Northamptonshire County Golf Club to the west, the River Nene to the east, and the Rugby to Milton Keynes railway line to the south. 3.3.3. At the time of writing the ESA (May 2020), the current land use and environmental characteristics of the Site remain unchanged. Section 2.4 of Chapter 2: The Existing Site (Volume II of the ES) identified key receptors which are relevant to the development of the Proposed Scheme design and EIA. Residential properties along A5199 Northampton Road, A5199 Welford Road, and Brampton Lane were considered as there is the potential for increases in noise level and visual impacts during construction and operation of the Proposed Scheme. 3.3.4. Since submission of the 2019 ES, construction work has started at two residential developments known as Buckton Fields West and Welford Road. Both developments were considered as committed developments within the 2019 ES, please refer to Chapter 5: Approach to EIA (Volume II of the ES). Consultation with Council (DDC) as part of the EIA Scoping process (please refer to Section 3.4 for further information) has identified that a small number of properties at Buckton Fields West are now occupied. Therefore, residents at Buckton Fields West have been considered as a new receptor as part of the baseline assessment of the ESA. 3.3.5. The Buckton Fields West development has also been considered as part of the future baseline and therefore has informed the cumulative assessment. Please refer to Section 3.5 for further information.

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SUMMARY OF NEW ENVIRONMENTAL INFORMATION 3.3.6. The following sections summarise any new environmental information which has become available to the Project Team since the submission of the 2019 ES. Updated Traffic Modelling (2020) 3.3.7. As part of the planning application submitted in June 2019, the Northamptonshire Strategic Transport Model (NSTM) was used as the basis to assess the impact of the Proposed Scheme on the operation of road network surrounding the Site. The NSTM informed the EIA process and the conclusions were reported in the 2019 ES, this included Chapter 6: Air Quality, Chapter 8: Climate Change, and Chapter 13: Noise and Vibration (Volume II of the 2019 ES). 3.3.8. The NSTM accounted for a range of committed developments within Northamptonshire County including all large proposed residential developments (by number of dwellings), major employment sites (by number of employees), and committed highway infrastructure schemes. 3.3.9. Following the submission of the planning application in June 2019, several components of the NSTM have been updated. These components include:  A change in the scale of development for some of the committed developments captured within the NSTM;  Finalised designs for the road junctions associated with the proposed Dallington Grange Development located adjacent to Proposed Scheme; and  Updated traffic flow information based upon traffic survey data gathered during surveys in May 2019. 3.3.10. The potential environmental impact of the revised traffic flows on air quality, noise, and climate change have been reported in the ESA, further detail can be found within Chapter 4: Air Quality, Chapter 5: Climate Change, and Chapter 7: Noise and Vibration (Volume II of the ESA). Ecological baseline work (2019) 3.3.11. Chapter 7: Biodiversity (Volume II of the June 2019 ES) reported on potentially significant effects as a result of the Proposed Scheme on protected habitats, species and designated sites. At the time of writing the 2019 ES, the presence of protected species and habitats on Site were based upon the results of protected species surveys conducted in 2017 and 2018. The results of the surveys were deemed to be indicative of the wider Site; however, in cases where the data was inconclusive, a precautionary approach within the 2019 ES was adopted. 3.3.12. Further ecological surveys were scheduled for 2019 and the 2019 ES indicated that the results of these surveys would be used to update and confirm conclusions made on certain species. Following the submission of the planning application in June 2019, WSP completed and reported on the additional ecological surveys across the Site and surrounding area in 2019. 3.3.13. The following reports were submitted to NCC Planning Department in September 2019:  Breeding Bird Survey Report;  Hedgerow Survey Report;  Badger Survey Report;  Barn Owl Survey Report;  Great Crested Newt Survey Report; and  Reptile Survey Report.

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3.3.14. In addition to the above, freshwater aquatic surveys, bat surveys, and kingfisher surveys were also completed across the Site in 2019. The results of those surveys can be found in Appendix 3.1-3.5 (Volume III of the ESA). 3.3.15. Following completion of the survey effort, as outlined above, a detailed review of the baseline assessment from the Chapter 7: Biodiversity (Volume II of the 2019 ES) alongside the design changes to the Proposed Scheme has been completed. Please refer to the Section 3.3 for further information. 3.4 SCOPE OF THE ESA EIA SCOPING ADDENDUM REQUEST 3.4.1. An EIA Scoping Addendum Report was submitted to the NCC Planning Department on 20 April 2020 in accordance with Regulation 15 of the EIA Regulations, please refer to Appendix 3.6: EIA Scoping Addendum Report (Volume III of the ESA). A formal Scoping Opinion was subsequently received from the NCC Planning Department on 02 June 2020, please refer to Appendix 3.7: EIA Scoping Addendum Opinion (Volume III of the ESA). 3.4.2. The NCC Planning Department undertook consultation with the following internal and external consultees in preparing the EIA Scoping Addendum Opinion:  NCC planning department and internal officers;  Daventry District Council;  Northampton Borough Council;  Highways England;  Environment Agency;  Natural England;  National Grid;  Western Power Distribution;  Wildlife Trust;  Network Rail;  Highways England; and  Historic England. 3.4.3. The EIA Scoping Addendum Report outlined that the Proposed Scheme has the potential to result in likely significant effects on the environment associated with the following topic areas or elements:  Air quality;  Biodiversity;  Climate change;  Landscape and visual;  Noise and vibration;  Population and human health;  Road drainage and the water environment; and  Cumulative effects. 3.4.4. These topics have therefore been taken forward and assessed within this ESA, except for those topics that have been scoped out of further assessment.

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ONGOING SCOPING 3.4.5. As part of ongoing scoping, several topics or elements have been scoped out of the EIA and are therefore not reported in the ESA. The following sections provide detail on this process and the justification for scoping out these topics/elements. Biodiversity Introduction 3.4.6. Chapter 7: Biodiversity (Volume II of the June 2019 ES) reported on potentially significant effects as a result of the Proposed Scheme on protected ecological designations, habitats, and species. Following a review of the updated environmental baseline information, and design changes to the Proposed Scheme, the biodiversity assessment has been revisited to determine whether there are any new or different significant effects that must be reported. 3.4.7. The following key receptors were considered as part of the review:  Statutory designated sites;  Non-statutory designated sites;  Habitats of Principal Importance (HPI);  On-site habitats;  Bats;  Badgers;  Breeding Birds;  Barn owl;  Kingfisher;  Otter; and  Reptiles. Assessment of baseline information 3.4.8. The 2019 surveys found additional evidence of most protected or notable species listed as key receptors in the 2019 ES, including further bat building roosts in Dallington Farm (outside of the Site), grass snake south of the Milton Keynes to Rugby railway line, presence of kingfisher along the River Nene (but no nest site), and additional badger setts outside of the Site. No otter holts, great crested newt ponds, bat tree roosts, or additional barn owl nest sites were identified in 2019. 3.4.9. As the additional results collected in 2019 are primarily outside of the Site and will not be impacted by the Proposed Scheme, the changes to baseline information are not considered significant and will not change the value of the receptors. Assessment of changes to Proposed Scheme 3.4.10. The changes to the design of the Proposed Scheme detailed above will result in additional habitat loss. 3.4.11. The high balancing pond has been moved from north of the carriageway to the south. The habitat type (poor semi-improved grassland) and the extent of area impacted is the same. No key receptors were identified in the new location of the balancing pond, and as such this change does not affect the magnitude of impact on any of the key receptors.

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3.4.12. The changes to the arms of the Brampton Lane Roundabout and Sandy Lane Roundabout will result in a minor increase in habitat loss. The habitats affected are arable land and poor semi-improved grassland, and as such the magnitude of impact on on-site habitats has not changed. 3.4.13. The proposed flood mitigation bund will result in the loss of a portion of the ditch classified as lowland fen habitat HPI, a key receptor. However, this ditch will be realigned, and additional compensatory habitat created to mitigate this impact. Furthermore, the ditch is a poor example of lowland fen habitat and the newly created diversion will be vegetated to better reflect this HPI. As such, the magnitude of impact on this receptor has not changed. 3.4.14. No other important ecological features (for example, bat roosts, badger setts, barn owl/kingfisher nest sites, or otter holts) were identified in these areas. As such, the magnitudes of impact on these receptors determined by the June 2019 assessment have not changed. Conclusion 3.4.15. A review of the updated environmental baseline information and design changes to the Proposed Scheme has concluded that the value of the ecological receptors has not changed, and the impacts of the Proposed Scheme on these receptors have also not changed. Therefore, the significance of the residual effects presented in Chapter 7: Biodiversity (Volume II of the 2019 ES) will remain unchanged. 3.4.16. The proposed mitigation and monitoring commitments outlined in the 2019 ES will be developed in partnership with relevant stakeholders, including the NCC Biodiversity Officer and Natural England. Landscape and Visual 3.4.17. Chapter 11: Landscape and Visual (Volume II of the 2019 ES) reported the assessment of likely significant effects on the landscape and on visual amenity arising from the Proposed Scheme. 3.4.18. As set out in Chapter 2: Changes to the Description of the Proposed Scheme (Volume II of the ESA), there have been a number of changes to the design of the Proposed Scheme. Those with the potential to change the landscape or visual amenity effects reported in the 2019 ES are as follows:  Realignment and extension of the northern arm of the proposed Sandy Lane roundabout, connecting to the A5199 Northampton Road towards ;  Relocation of the balancing pond from the north side of the Causeway to the south side;  The redesign of the flood storage replacement areas located immediately north of the Milton Keynes to Rugby railway line; and  The introduction of a Flood Mitigation Bund, approximately 280m long, 20m wide and up to 2m high, between this basin and the river. 3.4.19. These are all changes of relatively small scale when compared to the degree of change that would arise from the Proposed Scheme as a whole: details of design rather than fundamental alterations. As such it is considered unlikely that any of these design changes, either alone or in combination with each other, would alter the significance of any effects reported in Chapter 11: Landscape and Visual (Volume II of the 2019 ES). 3.4.20. The greatest change would be experienced by users of the footpath that crosses the river at the south end of the Brampton Valley then crosses the railway (receptor REC 3 in Chapter 11: Landscape and Visual, Volume II of the 2019 ES). This path would be diverted around the flood bund during construction and on completion would cross the bund.

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3.4.21. This receptor was assessed in the 2019 ES as being subject to a large adverse effect during construction falling to moderate to large on completion and remaining at that level over time. 3.4.22. The introduction of the flood mitigation bund would be a relatively small change and as such not increase the significance of these effects. 3.4.23. The proposed landscape mitigation design has been developed to take account of these changes and is shown in Figure 11.6: Landscape Mitigation and Preliminary Design (Volume IV of the ESA). The revised design provides the same level of landscape and visual mitigation to all receptors as was provided by the mitigation design included in the 2019 ES. 3.4.24. The requirement to assess the potential landscape and visual effects arising from the changes in the Proposed Scheme design has been scoped out because the Proposed Design changes are predicted to not alter the significance of the effects reported in the 2019 ES. 3.4.25. The landscape and visual assessment in the 2019 ES considered the receptors that existed at the time of writing – April/May 2019. Changes to the pattern and extent of future development that were known about were discussed as part of the future baseline and, for certain residential receptors, the assessment noted that the effects on them would reduce over time because of changes to the view they would experience as the planned development was built out. 3.4.26. Since the publication of the 2019 ES, parts of this future baseline have been constructed. In particular, the developments at Buckton Fields West and Welford Road (as detailed in Section 3.3 and 3.5) Chapter 3: Approach to EIA (Volume II of the ESA)) are under construction and some properties within the Buckton Fields West site are understood to have been occupied. 3.4.27. This change to the baseline will alter the predicted visual effect from the adjacent housing area, the northern edge of Spring Park (Receptor R7 in Chapter 11: Landscape and Visual, Volume II of the 2019 ES). In addition, and on the understanding that some properties at the Buckton Fields West site are occupied and the properties at the Welford Road site will very shortly be occupied, it introduces two new residential receptor groups. 3.4.28. Therefore, any potential visual effects on the two new residential receptor groups must be reported within the ESA. In addition, any change to the reporting of visual effects associated with Receptor R7 must also be reported. Please refer to Chapter 6: Landscape and Visual (Volume II of the ESA). Population and Human Health 3.4.29. As set out in Chapter 2: Changes to the Description of the Proposed Scheme (Volume II of the ESA), there have been a number of changes to the design of the Proposed Scheme following the submission of the 2019 ES. The design changes with the potential to impact the population and human health assessment reported in the 2019 ES are as follows:  Relocation of the balancing pond from the north side of the Causeway link to the south side;  The redesign of the flood storage replacement areas located immediately north of the Milton Keynes to Rugby railway line; and  The introduction of a flood mitigation bund.

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3.4.30. The highway balancing pond has been moved from north of the carriageway to the south. The land for the new location of the balancing pond is within the same agricultural land holding (Land holding title HN14529) as the original design, and the extent of area impacted is the same. As such this change does not change the predicted magnitude of impact or significance of effect reported for the affected land holding in the 2019 ES. 3.4.31. The amendments to the Proposed Scheme will require a larger area of agricultural land, primarily to accommodate temporary construction works. As a result, there are three agricultural land holdings that will experience an increased loss of agricultural land (Land holding titles NN316999, NN18329, and NN128038). The 2019 ES assumed, as a worst-case scenario, that all agricultural land required for the construction of the Proposed Scheme would be permanently lost. In reality, agricultural land will be reinstated before operation of the Proposed Scheme, where possible. This will be implemented by the Contractor as part of the Construction Environmental Management Plan (CEMP) and as agreed with the landowners. In addition, accommodation access arrangements have been incorporated as part of the Proposed Scheme. 3.4.32. Following the implementation of this mitigation, the 2019 ES reported a moderate adverse effect on agricultural land holding which is considered significant. It is considered that the increase in land take will not change the predicted magnitude of impact or significance of effect as reported in the 2019 ES because of the temporary nature of any impacts on the additional agricultural land. 3.4.33. The redesign of the flood storage replacement areas and introduction of a flood mitigation bund will impact both Public Footpath HW44 and Bridleway HW6 during both the construction and operational phases. The impacts experienced by non-motorised users (NMUs) of these routes are not predicted to differ from those identified in the 2019 ES, which included temporary closure during construction and a permanent diversion once the scheme is operational. The predicted magnitude of impact and significance of effect reported in the 2019 ES are not predicted to change as a result of the proposed design changes. 3.4.34. The changes to the design of the Proposed Scheme will impact agricultural land holdings and NMUs using Public Footpath HW44 and Bridleway HW6. However, the proposed design changes are not predicted to pose any new, or different, significant adverse effects to those reported in Chapter 14: Population and Human Health (Volume II of the 2019 ES). 3.4.35. The assessment of human health in the 2019 ES was informed by the outcomes of the assessments of Air Quality (2019 ES Chapter 6), Noise and Vibration (2019 ES Chapter 13), and Road Drainage and the Water Environment (2019 ES Chapter 15). Following the changes to the design of the Proposed Scheme, these assessments have been re-visited and are reported on below in Chapter 4: Air Quality, Chapter 7: Noise and Vibration, and Chapter 8: Road Drainage and the Water Environment (Volume II of the ESA). 3.4.36. The assessments of air quality, noise and vibration and road drainage and the water environment have not identified any new, or different, significant adverse effects as a result of the Proposed Scheme. Therefore, the effects on Population and human health, as presented in Chapter 14: Population and Human Health (Volume II of the 2019 ES) will remain unchanged.

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SUMMARY OF ESA SCOPE 3.4.37. The following topics have been taken forward and assessed as part of this ESA:  Air quality (please refer to Chapter 4);  Climate change (please refer to Chapter 5);  Landscape and visual (please refer to Chapter 6);  Noise and vibration (please refer to Chapter 7);  Road drainage and the water environment (please refer to Chapter 8); and  Cumulative effects (please refer to Technical Chapter 4-8). 3.4.38. This ESA must be read in conjunction with the 2019 ES. To assist the reader in locating the most up to date information regarding the EIA, Table 3-1 provides a breakdown of the technical topics that have been considered as part of the EIA and the location for the most up to date assessment.

Table 3-1: Summary of EIA scope and location of relevant assessment within the ES and ESA

Technical Topic 2019 ES 2020 ESA / Introduction

Introduction Refer to Chapter 1 (Volume II Refer to Chapter 1 (Volume II of the ESA). of the 2019 ES).

The Existing Site Refer to Chapter 2 (Volume II The content of Chapter 2 (Volume II of the 2019 ES) of the 2019 ES). remains valid. However, please refer to Section 3.3 (Volume II of the ESA) for details of additional residential receptors and new baseline information which has informed the ESA.

Description of the Refer to Chapter 3 (Volume II The content of Chapter 3 (Volume II of the 2019 ES) Proposed of the 2019 ES). remains valid. However, please refer to Chapter 2 Scheme (Volume II of the ESA) for details of design changes to the Proposed Scheme.

Consideration of Refer to Chapter 4 (Volume II The alternatives assessment within the 2019 ES Alternatives of the 2019 ES). remains valid. No further work has been reported in the ESA.

Approach to EIA Refer to Chapter 5 (Volume II The content of Chapter 5 (Volume II of the 2019 ES) of the 2019 ES). remains valid. However, please refer to Chapter 3 (Volume II of the ESA) for details of; the EIA scoping process which informed the ESA, updated information on committed developments, and updates to supporting assessment work.

Air quality Refer to Chapter 6 (Volume II An updated air quality impact assessment has been of the 2019 ES). carried out to account for the updated traffic information and design changes to the Proposed Scheme. This updated assessment supersedes the assessment presented in Chapter 6 (Volume II of the 2019 ES). Please refer to Chapter 4 (Volume II of the ESA) for further details.

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Technical Topic 2019 ES 2020 ESA / Introduction

Biodiversity Refer to Chapter 7 (Volume II Following a detailed review of new environmental of the 2019 ES). baseline information and the design changes to the Proposed Scheme, a detailed biodiversity impact assessment has been scoped out of the ESA. The conclusions presented in Chapter 7 (Volume II of the 2019 ES) remain valid. Please note that an updated HRA Stage 2 Report and addendum to the BNG Assessment can be found in Volume III of the ESA.

Climate Change Refer to Chapter 8 (Volume II As set out in the EIA Scoping Addendum Report and of the 2019 ES). agreed with NCC Planning Department, residual The assessment considered effects in relation to the vulnerability / resilience of the contribution of GHG from the Proposed Scheme to climate will remain the Proposed Scheme & the unchanged, therefore, this has been scoped out of vulnerability / resilience of the ESA. The residual effects presented in Chapter 8 Proposed Scheme to climate (Volume II of the 2019 ES) remain valid. change. The contribution of GHG emissions from the Proposed Scheme could change as a result of updates to the traffic data. Therefore, an updated GHG assessment has been carried out. This updated GHG supersedes the assessment presented in Chapter 8 (Volume II of the 2019 ES). Please refer to Chapter 5 (Volume II of the ESA) for further details.

Cultural Heritage Refer to Chapter 9 (Volume II As set out in the EIA Scoping Addendum Report and of the 2019 ES). agreed with NCC Planning Department, residual Refer to Addendum to the effects in relation to cultural heritage assets will Historic Environment Desk- remain unchanged, therefore, this has been scoped Based Assessment (HEDBA) out of the ESA. The conclusions presented in and Cultural Heritage Chapter 9 (Volume II of the 2019 ES) and the submitted to NCC in September 2019 addendum therefore remain valid. September 2019.

Geology and Refer to Chapter 10 (Volume II As set out in the EIA Scoping Addendum Report and Soils of the 2019 ES). agreed with NCC Planning Department, residual effects in relation to geology and soils will remain unchanged, therefore, this has been scoped out of the ESA. The conclusions presented in Chapter 10 (Volume II of the 2019 ES) therefore remain valid.

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Technical Topic 2019 ES 2020 ESA / Introduction

Landscape and Refer to Chapter 11 (Volume II As identified in Section 3.4, the new environmental Visual of the 2019 ES). baseline information and design changes to the Proposed Scheme will not change the significance of effects reported in Chapter 11 (Volume II of the 2019 ES). However, the change to baseline conditions requires a reassessment of visual effects on one residential receptor and an assessment of two new residential receptors. Please refer to Chapter 6 (Volume II of the ESA) for further details.

Material Assets Refer to Chapter 12 (Volume II As set out in the EIA Scoping Addendum Report and and Waste of the 2019 ES). agreed with NCC Planning Department, residual effects in relation to material assets and waste will remain unchanged, therefore, this has been scoped out of the ESA. The conclusions presented in Chapter 12 (Volume II of the 2019 ES) therefore remain valid.

Noise and Refer to Chapter 13 (Volume II An updated noise impact assessment has been Vibration of the 2019 ES). carried out to account for the updated traffic information and design changes to the Proposed Scheme. This updated assessment supersedes the assessment presented in Chapter 13 (Volume II of the 2019 ES). Please refer to Chapter 7 (Volume II of the ESA) for further details.

Population and Refer to Chapter 14 (Volume II Following a detailed review of new environmental Human Health of the 2019 ES). baseline information and the design changes to the Proposed Scheme, a detailed population and human health impact assessment has been scoped out of the ESA. The conclusions presented in Chapter 14 (Volume II of the 2019 ES) remain valid.

Road Drainage Refer to Chapter 15 (Volume II An updated road drainage and water environment and the Water of the 2019 ES). assessment has been carried out to account for the Environment updated traffic information and design changes to the Proposed Scheme. This updated assessment supersedes the assessment presented in Chapter 15 (Volume II of the 2019 ES). Please refer to Chapter 8 (Volume II of the ESA) for further details.

Summary of Refer to Chapter 16 (Volume II A summary of residual effects reported in Chapter 4 Effects of the 2019 ES). – 8 (Volume II of the ESA) are reported in Chapter 9 (Volume II of the ESA). This chapter should be read in conjunction with Chapter 16 (Volume II of the 2019 ES).

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3.5 CUMULATIVE ASSESSMENT INTRODUCTION 3.5.1. Cumulative effects result from multiple actions on receptors and resources over time and are generally additive or interactive (synergistic) in nature. Cumulative effects can also be considered as effects resulting from incremental changes caused by other past, present or reasonably foreseeable actions together with the Proposed Scheme. 3.5.2. Schedule 4(5(e)) of the EIA Regulations states that the ES should include a description of the likely significant effects of the development on the environment resulting from ‘the cumulation of effect with other existing and / or approved projects, considering any existing environmental problems relating to areas of particular environmental importance likely to be affected or the use of natural resources’. These are known as cumulative effects. Regulation 4(2(e)) of the EIA Regulations refers to the need to assess ‘the interaction between the factors referred to in sub-paragraphs (a) to (d) [where these sub-paragraphs refer to topic-specific factors]. These are known as combined effects. 3.5.3. There is no widely accepted methodology or best practice for assessing cumulative effects although various guidance documents exist. The approach adopted for this assessment of cumulative effects is based on previous experience, the types of receptors being assessed, the nature of the Proposed Scheme, the other developments under consideration, and the information available to inform the assessment. 3.5.4. The over-arching approach to the cumulative effect assessment was outlined in the EIA Scoping Report (Appendix 5.3: EIA Scoping Request (Volume III of the ES)) submitted to NCC in August 2018. This section outlines any changes or updates required in the approach to the cumulative assessment since submission of the 2019 ES. CUMULATIVE EFFECTS 3.5.5. The cumulative effects assessment within the 2019 ES was approached on a topic by topic basis. The assessment was based upon the residual effects that were identified in Chapters 6 – 15 (Volume II of the 2019 ES) as well as available environmental information for the committed developments. For the purposes of the 2019 ES, ‘reasonably foreseeable’ was interpreted to include other projects that are ‘committed’ and fall within the following categories:  Trunk Road / Other Road projects which have been confirmed (i.e. gone through the statutory processes);  Development projects with valid planning permissions (for which statutory EIA is a requirement or a non-statutory EIA has been undertaken); and  Development projects which have submitted planning applications (for which statutory EIA is a requirement or a non-statutory EIA has been undertaken). 3.5.6. The Project team determined that a 2km cumulative project study area would be proportionate given the scale and nature of the Proposed Scheme. This approach was agreed with NCC’s Planning Department, DDC, and NBC.

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3.5.7. The EIA Scoping Addendum Report (please refer to Appendix 3.6: EIA Scoping Report Addendum (Volume III of the ESA)) set out that the methodology for the assessment of cumulative effects, including the determination of significance, would be unchanged from those set out in the EIA Scoping Report (please refer to Appendix 5.3: EIA Scoping Request (Volume III of the 2019 ES)) and 2019 ES. 3.5.8. A review of publicly available information relating to committed developments within a 2km cumulative project study area has been carried out to inform the scope of the ESA. The review included any developments requesting planning permission submitted to NCC, DDC, and NBC within the study area between January 2019 and April 2020 that meet the criteria set out in the bullets in paragraph 3.4.5. 3.5.9. The review concluded that there are no new or previously unaccounted-for committed developments that need to be assessed as part of the ESA (i.e. no new EIA developments or developments of qualifying nature and proximity which require inclusion in the cumulative assessment). However, it is recognised that the status of some of the committed developments assessed within the 2019 ES will have changed over time. 3.5.10. In order to obtain the most relevant information regarding each of the committed developments within the study area, a Cumulative Scoping Note was submitted to NCC Planning Department, Daventry District Council, and Northampton Borough requesting this information, please refer to Appendix 3.8: Cumulative Scoping Note (Appendix III of the ESA). 3.5.11. An overview of the committed developments and supporting environmental documentation used for the cumulative effect assessment is presented in Table 3-2 (overleaf). This list has been agreed with NCC Planning Department, DDC, and NBC. The discussion of cumulative effects within the ESA has been approached on a topic by topic basis, dependent upon the availability of relevant information. Please also refer to Figure 3.1 – Committed Developments (Volume IV of the ESA).

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Table 3-2: Summary of committed developments

Status (2019 ES) Proposal and Material Committed Status (April Distance Reviewed to Inform Development 2020) from Site Assessment

Dallington Outline Planning No change. The Outline Planning Application (all Grange Application. Proposed matters reserved except access) Approved in- Scheme sits for a Sustainable Urban principle subject immediately Extension, including; to conditions north of the  Up to 3,000 dwellings; (2018). Dallington  Up to 7.2ha employment land; Grange  A local centre; development.  Nursery/two primary schools/secondary school;  Redevelopment of Grange Farm for café / restaurant / public house or hotel;  Extension of the North-West Bypass;  Provision of open space and strategic landscaping and wildlife corridors;  Surface water / flood management works and associated engineering works for drainage and services.

ES was submitted as part of Outline Planning Application.

Buckton Outline Planning Reserved matters Approx. Outline Planning Application (all Fields West Application for for Buckton Fields 100m south- matters reserved except access, Buckton Fields West submission east of internal spine road and West and East and approval Proposed development) for a mixed used submitted (2011) (2019). Scheme (the development comprising: and approved Buckton Fields proposed  Up to 1050 dwellings (C3); (2018). West is currently Brampton  B1 employment, residential under Lane care home (C2); construction. First Roundabout).  Park and ride facility of up to occupation 500 spaces; occurred at the  Local centre (A1/A2/A3/A5); start of March  Primary school; and 2020.  Public open space and associated highways and drainage infrastructure.

ES was submitted as part of Outline Planning Application. Supporting engineering drawings and detailed design proposals submitted as part of reserved matters application.

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Status (2019 ES) Proposal and Material Committed Status (April Distance Reviewed to Inform Development 2020) from Site Assessment

Buckton Outline Planning Outline Planning Approx. Outline Planning Application (all Fields East Application Application 700m south- matters reserved except access, submitted (2011) submitted (2011) east of internal spine road and and approved and approved Proposed development) for a mixed used (2018). (2018). Scheme (the development comprising: Reserved matters Reserved matters proposed  Up to 1050 dwellings (C3); for Buckton Fields for Buckton Fields Brampton  B1 employment, residential East submission East submission Lane care home (C2); (2013) and (2013) and Roundabout).  Park and ride facility of up to approval (2014). approval (2014). 500 spaces; Buckton Fields Buckton Fields  Local centre (A1/A2/A3/A5); East was under East is under  Primary school; and construction. construction and  Public open space and close to associated highways and drainage infrastructure. completion. ES was submitted as part of Outline Planning Application (2011). Supporting engineering drawings and detailed design proposals submitted as part of reserved matters application.

Welford Road Outline Planning Project under Approx. Outline Planning Application for Application for up construction. 200m south up to 41 dwellings, Estate road, to 41 dwellings, of Proposed and Open space and associated Estate road, and Scheme (the works. Open space and proposed Supporting plans, Design and associated works. Brampton Access Statement, and Submitted (2014) Lane landscape plan. and approved Roundabout). (2015). Reserved matters application submitted (2018) and approved (2019). Superseding to previous reserved matters applications in 2017 and 2018.

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INTRA-PROJECT CUMULATIVE EFFECTS 3.5.12. The approach to the assessment of interactions of environmental effects considers the changes in baseline conditions at common sensitive receptors (i.e. those receptors that have been identified as experiencing likely significant effects by more than one technical topic) due to the Proposed Scheme. The assessment is based upon residual effects only (considered to be effects of slight or greater significance i.e. excluding neutral effects). The study area for the assessment is informed by the study areas for the individual topic assessments as set out in Technical Chapters 4-8. 3.5.13. An assessment of the cumulative effects on the common sensitive receptors identified above has been made using professional judgement and the technical information provided in Technical Chapters 4-8. 3.6 SUPPORTING ASSESSMENT WORK 3.6.1. Chapter 5: Approach to EIA (Volume II of the 2019 ES) outlined that, whilst separate to the EIA, a Habitats Regulations Assessment (HRA) and Water Framework Directive (WFD) assessment had been co-ordinated and carried out in support of the planning application. Whilst the scope, level of detail, and terminology used in all three assessments often varies, it was important that the information and needs of these assessments were considered in parallel to ensure the 2019 ES was complaint with Regulation 27 of the EIA Regulations. 3.6.2. Following the same approach, there was a requirement to update the HRA and WFD assessment as a result of the changes to the Proposed Scheme design and the updated environmental information. The following sections summarise this process and direct the reader to the relevant documentation. Habitats Regulation Assessment (HRA) 3.6.3. Under the requirements of the European Council Directive 92/43/EEC ‘The Habitats Directive’ and the Council Directive 79/409/EEC ‘The Wild Birds Directive’ (translated into UK law through the Conservation of Habitats and Species Regulations 2017, as amended) (Ref. 3-1), it is necessary to consider whether the Proposed Scheme may have significant effects upon areas of nature conservation importance designated/classified under the Directives. This process is known as the HRA. 3.6.4. The HRA process consists of several stages, the first of which is known as screening. The screening stage is the process of identifying potentially relevant Natura 2000 sites1 and determining whether the likely impacts of the plan or project upon the qualifying features of the site, either alone or in- combination with other plans and projects, are likely to be significant.

1 Natura 2000 is a network of nature protection areas in the territory of the European Union. It is made up of Special Areas of Conservation and Special Protection Areas designated respectively under the Habitats Directive and Birds Directive. The network includes both terrestrial and Marine Protected Areas.

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3.6.5. An HRA Stage 1 Report was submitted as part of the planning application in June 2019, please refer to Appendix 7.14 (Volume IV of the ES). The Site of the Proposed Scheme is located within 5.5km of the Upper Nene Valley Gravel Pits Special Protection Area (SPA), Ramsar site, and Site of Special Scientific Interest (SSSI). The in-combination effects arising from the adjoining Dallington Grange Development and committed developments within Northampton Borough were deemed

likely to result in significant impacts on the Natura 2000 site through increase Nitrogen Oxide (NOx) deposition due to increased traffic flow along the A45 carriageway. A Stage 2 Appropriate Assessment was therefore required. 3.6.6. In September 2019, a HRA Stage 2 Report was submitted to NCC Planning Department. Air quality modelling was undertaken to compare a Do minimum (DM) scenario, which includes all other developments but not the Proposed Scheme, and a Do something (DS) scenario, which also includes the Proposed Scheme. Modelling was run to predict changes in air quality in the years 2021 (opening year of the Proposed Scheme) and 2031 (design assessment year in line with air quality assessment). The report concluded that the Proposed Scheme will not result in a significant effect on the integrity of the Upper Nene Valley Gravel Pits SPA, Ramsar site, and SSSI. An updated Air quality Impact Assessment has been completed based on the updated traffic model and reported within the ESA (please refer to Chapter 4: Air Quality (Volume II of the ESA)). 3.6.7. To ensure the conclusions of the HRA Stage 2 Appropriate Assessment are based on the most up to date traffic information and associated air quality modelling, an updated HRA Stage 2 Appropriate Assessment has been prepared in support of the planning application, please refer to Appendix 3.9: Updated HRA – Stage 2 Appropriate Assessment Report (Volume III of the ESA). Water Framework Directive (WFD) 3.6.8. The Water Framework Directive (2000 / 60 / EC) was transposed into UK legislation by the Water Environment (WFD) Regulations 2017 (Ref. 3-2). The Directive aims to prevent the deterioration of aquatic ecosystems and associated wetlands through reducing pollution of surface and ground water whilst contributing to flood mitigation. Under WFD legislation, no deterioration of waterbodies is permitted. 3.6.9. A WFD Assessment was required in support of the planning application to demonstrate that the Proposed Scheme will not result in deterioration of the current quality status of the relevant WFD water bodies in accordance with the objectives and measures set out in the Anglian River Basin Management Plan (RBMP), please refer to Appendix 15.1 (Volume III of the ES). 3.6.10. To ensure the conclusions of the WFD Assessment are based on the most up to date design and environmental information, an updated WFD Assessment has been prepared in support of the Planning Application, please refer to Appendix 3.10: Water Framework Directive Assessment (Volume III of the ESA). Transport Assessment 3.6.11. A Transport Assessment (TA) has been prepared to support the planning application for the Proposed Scheme. Following the submission of the planning application in June 2019, WSP received a number of comments from stakeholders with regards to the original TA. As a result, a Transport Assessment Addendum (TAA) was submitted to NCC Planning Department in September 2019.

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3.6.12. Since submission of the TAA, updated traffic flow and committed development information, as discussed in Section 3.3 (Volume II of the ESA), has established the need for further updates to the TA. Therefore, an updated TA has been prepared in support of the planning application which supersedes the previous submitted TA (May 2019) and subsequent TAA (September 2019). Please refer to Appendix 3.11: Transport Assessment (Volume III of the ESA). Biodiversity Net Gain (BNG) Assessment 3.6.13. A BNG Assessment was submitted in support of the June 2019 planning application, please refer to Appendix 7.15 (Volume IV of the 2019 ES). BNG is a quantitative, stepwise process which is applied to development and results in an overall net gain in biodiversity after development. The principle behind it is that any impacts from development to biodiversity need to be accounted for and compensated with equivalent and additional gains. 3.6.14. The design changes to the Proposed Scheme, as presented in Section 2.0, will alter the quantitative analysis presented in the BNG Assessment. Therefore, a supplementary note has been prepared in support of the ESA to reflect these minor amendments. Please refer to Appendix 3.12: BNG Technical Note (Volume II of the ESA). 3.6.15. The commitments and recommendations presented in Appendix 7.15 (Volume IV of the 2019 ES) will remain, therefore a full BGN Assessment will be prepared following confirmation of the temporary works layout and final landscape plan, this information will be available as part of the detailed design of the Proposed Scheme. 3.7 LIMITATIONS AND ASSUMPTIONS 3.7.1. Schedule 4(6) of the EIA Regulations states that an ES should include '...details of difficulties (for example technical deficiencies or lack of knowledge) encountered compiling the required information and the main uncertainties involved…' 3.7.2. Where there are limitations or assumptions used within the EIA, these are clearly identified in this ESA. Limitations and assumptions specific to certain topics have been identified in the appropriate Technical Chapters 4-8. 3.8 REFERENCES  Ref. 3-1: Conservation of Habitats and Species Regulations 2017 (as amended)  Ref. 3-2: Water Environment (WFD) Regulations 2017

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4 AIR QUALITY

4.1 INTRODUCTION 4.1.1. This chapter describes the air quality impact assessment undertaken for the Proposed Scheme, the outcomes of which are used to determine the likely significant effects on local air quality. The assessment has been undertaken with reference to guidance from the Institute of Air Quality Management (IAQM) (Ref. 4.3, Ref 4.10) Environmental Protection UK (EPUK) (Ref. 4.10) and the government’s Design Manual for Roads and Bridges (DMRB) LA 105 (Ref 4.1). These guidance documents set out the requirements for assessing and reporting the effects of locally and nationally significant highway projects on air quality. 4.1.2. The level of air pollution adjacent to roads and within urbanised areas is typically a function of

vehicle emissions. Emissions of nitrogen oxides (NOx, including nitrogen dioxide, NO2) and

particulate matter (PM10 and PM2.5) from vehicles are of greatest concern with respect to human health. Concentrations of these pollutants are subject to air quality standards, established by UK legislation for the protection of human health. 4.1.3. The air quality assessment considers likely significant effects associated with the following activities:  Emissions associated with the construction phase of the Proposed Scheme with a focus on construction dust emissions; and  Emissions associated with the operational phase of the Proposed Scheme with a focus on vehicle emissions. 4.1.4. The chapter also identifies, where appropriate, mitigation to prevent, minimise or control likely adverse air quality effects arising from the construction and operation phases of the Proposed Scheme and the subsequent residual effects. 4.1.5. This chapter is intended to be read together with the associated appendices (Appendix 4.1 to 4.5 (Volume III of the ESA)) and introductory chapters of the ESA (Chapters 1-3). CONSULTATION 4.1.6. Table 4-1 provides a summary of the consultation activities undertaken in support of the preparation of this chapter.

Table 4-1: Summary of consultation undertaken

Body / Individual / stat Meeting dates and Summary of outcome of organisation body / other forms of discussions organisation consultation

 To conclude, this application will Public Health Jamie Bond,  21/8/2019 Letter lead to increased levels of air England Environmental to Peter Moor, pollution at, in some cases, Public Health Principal thousands of sensitive receptors in Scientist Development both the short (2021 scenario) and Control Officer long term (2031). Evidence from (Ref 4.19) COMEAP (the Committee on the Medical Effects of Air Pollutants), shows a relationship between air pollution and both mortality and

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Body / Individual / stat Meeting dates and Summary of outcome of organisation body / other forms of discussions organisation consultation

morbidity which continues below Air Quality Standards. For these pollutants there is no threshold below which population effects are unlikely to occur.  The proposed development will contribute a greater proportion of the total air pollution burden as other sources decline and accordingly PHE requests that this application be considered in this context.

 It is noted that DEFRA emission Northampton Gavin Smith,  27/4/2020 Email factor toolkit (Version 9) will be used Borough Council Senior from WSP to EHO to determine the predicted impact. (NBC) Environmental and return emails  Using the LA105 guidance the study Health Officer on 30/4/2020 area should be expanded if new (EHO),  30/4/2020 road links are deemed to be Environmental Telephone call affected by the scheme. This should Protection EHO to WSP ensure more of central Northampton  4/5/2020 Email is captured within the study area from EHO to Peter and outcomes are representative. Moor, Principal  It is requested that the following Development three areas be included within the Control Officer study area if the relevant road links have been identified. • White Elephant Junction (Race Course/ Kettering Road). • The Drapery and North Gate Bus Station area. • Abington Square Area.  It is requested the applicants air quality consultant (WSP) undertake sensitivity testing on local and national bias adjustment factors used for validation purposes.  Documents provided: A technical paper for Defra (Ref 4.20) by Bureau Veritas to substantiate why certain bias adjustment factors were applied over the last 5 years for clarity.

Daventry District Mike Jephcott,  27/4/2020 Email  The updated assessment must Council (DDC) Senior EHO, from WSP to EHO demonstrate the impact these Environmental  7/5/2020 Email [updated model] adjustments will Health from EHO to have with respect to noise and air Steve Ellis, Major quality. Projects Officer  I highlighted the property at Boughton Crossing and the need to

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Body / Individual / stat Meeting dates and Summary of outcome of organisation body / other forms of discussions organisation consultation

 7/5/2020 ensure the air quality impact is not Telephone call such that we will have to declare an EHO to WSP AQMA; I would expect any additional information to consider

this and ensure adequate mitigation is employed.

SCOPE OF THE ASSESSMENT 4.1.7. The local air quality assessment has involved an evaluation of changes in concentrations of specific pollutants at sensitive receptors located in close proximity to the parts of the road network that will be affected by the Proposed Scheme. The pollutants considered in relation to sensitive receptors

comprise oxides of nitrogen (NOX, including nitrogen dioxide, NO2) and particulates (PM2.5 and PM10) which are constituent pollutants vehicle exhaust gas emissions. Existing concentrations and trends of the specified pollutants, as well as the location of Air Quality Management Areas (AQMAs) relative to the Proposed Scheme, have been investigated. 4.1.8. The sensitive receptors considered include:  Inhabitants of residential properties, schools and care homes within 200m of the relevant sections of the existing road network and the Proposed Scheme, identified in accordance with the scoping criteria detailed in LA 105 (Ref. 4.1);  Locations where a significant number of the people could be present on a regular basis, including properties where those more vulnerable to the effects of poor air quality. For example, the young and the elderly, regularly congregate such as schools, hospitals and care homes; and  Any designated sensitive ecological site such as a Special Area of Conservation (SAC), Special Protection Area (SPA), Sites of Special Scientific Interest (SSSI) or Ramsar sites within 200m of an affected road link. Details of the sensitive ecological sites to be investigated can be found in LA 105 (Ref. 4.1). 4.1.9. The part of the existing road network which comprises the study area for the local air quality assessment, as defined by DMRB LA 105, includes sections of road (referred to as ‘affected roads’) that are predicted to meet the following scoping criteria:  A change in annual average daily traffic (AADT) >=1,000; or  A change in heavy duty vehicle (HDV) AADT >=200; or  A change in speed band; or  A change in carriageway alignment by >=5m 4.1.10. All affected roads and adjoining roads within 200m are defined as the ‘affected road network’ (ARN). 4.1.11. Traffic data provided by the project’s Design Team were screened in accordance with these criteria to identify affected road links and the extent of the study area. 4.1.12. The extent of the study area is shown in Figure 4.1: Study area, AQMA, and Affected Road Network (Volume IV of the ESA), and the receptor locations included within the local air quality assessment are depicted in Figure 4.6: Residential and Ecological Receptors (Volume IV of the ESA).

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Elements scoped out of the assessment 4.1.13. The elements shown in Table 4-2 are not considered to give rise to likely significant effects because of the Proposed Scheme and have therefore not been considered within the ESA.

Table 4-2: Elements scoped out of the assessment

Element scoped out Justification

The potential for the Proposed Scheme to impact LA 105 (Ref 4.1) does not require the assessment of regional emissions of NOx, PM10 and CO2 regional emissions. This topic will be covered in Chapter 5: Climate Change.

Quantitative assessment of emissions of on-road It is unlikely that there will be sufficient on-road construction vehicles, traffic diversions and road construction vehicles to warrant quantitative closures assessment

The assessment of three specific areas within Traffic flows are predicted to reduce in these three Northampton, as requested by the NBC EHO: focus areas. These locations are not within the study area identified for the Proposed Scheme, as the  White Elephant Junction (Race Course/ Kettering traffic data provided for these areas does not meet Road). the scoping criteria outlined in LA 105 (Ref 4.1) for  The Drapery and North Gate Bus Station area. inclusion within the affected road network (Section  Abington Square Area. 4.1.9). LIMITATIONS AND ASSUMPTIONS 4.1.14. The modelling of future air quality is subject to uncertainty, which is manifest in the differences between modelled and measured pollutant concentrations. These differences can be explained by a number of uncertainties in the accuracy and representativeness of datasets including:  Assumed construction phase pollution source activities;  Modelled and monitored background concentrations;  Meteorological data;  Source activity data such as traffic flow data and vehicle emissions factors;  Model input parameters such as roughness length, minimum Monin-Obukhov length, and overall model limitations; and  Pollutant monitoring data including site locations and methods of bias correction (See Section 4.5 Supplementary Analysis). Model Verification 4.1.15. The application of model verification allows the differences between modelled and measured pollutant concentrations resulting from these uncertainties to be investigated. Through appropriate adjustment of the model outputs, uncertainty can be minimised to improve the consistency of modelling results in comparison to monitored data. 4.1.16. To evaluate model performance, the verified model results were subjected to statistical analyses to establish confidence in the results being presented. The statistical parameters used to assess model performance comprised:  Root Mean Square Error;  Correlation Coefficient; and  Fractional Bias.

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4.1.17. The model adjustment factors for pollutants derived through this process were applied to all subsequent model scenario outputs in the operational phase assessment. Estimates of Vehicle Emissions 4.1.18. For the modelling of future year scenarios, another uncertainty relates to the projection of vehicle emissions and, in particular, the rate at which emissions per vehicle will improve over time. This assessment has utilised the most recent version of Department for Environment, Food and Rural Affairs (Defra) Emissions Factors Toolkit to provide the most up to date estimate of current and future vehicle emissions projections. 4.1.19. Current projections for vehicle emissions factors are only available until 2030, which precedes the 2031 future year scenario (Section 4.2). Therefore, vehicle emissions factors adopted for these future years have been based on the 2030 projected factors which means changes in emissions beyond 2030 cannot be represented. 4.2 METHODOLOGY LEGISLATIVE FRAMEWORK 4.2.1. A summary of the legislative framework relevant to the Proposed Scheme can be found below. A detailed review is presented in Appendix 4.1: Legislation, Policy, and Guidance (Volume III of the ESA). European and National Legislation UK Air Quality Strategy 4.2.2. The Governments policy on air quality within the UK is set out in the Air Quality Strategy for England, Scotland, Wales and Northern Ireland (AQS) (Ref 4.5). The AQS provides a framework for reducing air pollution in the UK with the aim of meeting the requirements of European Union legislation. 4.2.3. Table 4-3 summarises the national Air Quality Objectives with relevance to this assessment.

Table 4-3: Relevant Air Quality Strategy Objectives

Pollutant Applies to Objective Measured As Dates to be achieved by

National Air Quality Objectives for the Protection of Human Health

Nitrogen Dioxide UK 200µg/m3 not to be 1 hour mean 31.12.2005 (NO2) exceeded more than 18 times a year

UK 40µg/m3 Annual Mean 31.12.2005

Particulate Matter UK (except 40µg/m3 Annual Mean 31.12.2004 (PM10) Scotland)

UK (except 50µg/m3 not to be 24 hour mean 31.12.2014 Scotland) exceeded more

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Pollutant Applies to Objective Measured As Dates to be achieved by than 35 times a year

Particulate Matter UK (except 25µg/m3 Annual Mean 2020 (PM2.5) Scotland)

National Air Quality Objectives set for the Protection of Vegetation and Ecosystems

Nitrogen Oxides UK 30µg/m3 Annual Mean 31.12.2000 (NOx)

4.2.4. LAQM.TG16 (Ref 4.2) advises that exceedances of the 1-hour mean NO2 objective are unlikely to occur where annual mean concentrations are below 60µg/m3, and it provides guidance on the

approach that should be taken if either measured or predicted annual mean NO2 concentrations are 60µg/m3 or above. 4.2.5. The Institute of Air Quality Management (IAQM) (Ref 4.3) and Defra (Ref 4.4) guidance provides an approach to assessing the relationship between annual mean and 24-hour mean concentrations of

PM10. Potential exceedances of the 24-hour objective are more likely where the annual mean concentration is over 32µg/m3. Clean Air Strategy (2019) 4.2.6. The Clean Air Strategy (Ref 4.6) outlines the Government’s plan to tackle all sources of air pollution. The strategy sets out the comprehensive action that is required from across all parts of government and society. New legislation will create a stronger and more coherent framework for action to tackle air pollution. This will be underpinned by new England-wide powers to control major sources of pollution, in line with the risk they pose to public health and the environment, plus new local powers to take action in areas with an air pollution problem. These will support the creation of Clean Air Zones to lower emissions from all sources of air pollution, backed up with clear enforcement mechanisms. Environmental Protection Act 1990- Control of Dust and Particulates associated with construction 4.2.7. The Environmental Protection Act 1990 (Section 79, Chapter 43, Part III- Statutory Nuisance and Inspections) (Ref 4.7) contains a definition of what constitutes a ‘statutory nuisance’ with regard to dust and places a duty on Local Authorities to detect any such nuisances within their area. Dust arising from construction works could lead to statutory nuisance if it, ‘interferes with the wellbeing of the residents, i.e. affects their wellbeing, even though it may not be prejudicial to health’. PLANNING POLICY 4.2.8. A summary of the national, regional and local planning policy relevant to the Proposed Scheme is provided below. A detailed review is presented in Appendix 4.1: Legislation, Policy, and Guidance (Volume III of the ESA).

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National Planning Policy Framework 4.2.9. The Governments overall planning polices for England are described in the National Planning Policy Framework (Ref 4.8). The core underpinning principle of the Framework is the presumption in favour of sustainable development. References to air quality include:  Paragraph 54 ‘…Local planning authorities should consider whether otherwise unacceptable development could be made acceptable through the use of conditions or planning obligations.  Paragraph 103 ‘…Significant development should be focused on locations which are or can be made sustainable’;  Paragraph 170 ‘…Planning policies and decisions should contribute to and enhance the natural and local environment’;  Paragraph 183 ‘…The focus of planning policies and decisions should be on whether proposed development is an acceptable use of land. Local Planning Policy 4.2.10. The current local planning policy relevant to the Proposed Scheme is the Joint Core Strategy Local Plan (Ref. 4.9). This policy incorporates the Northampton Borough Council and Daventry District Council areas. Policy BN9 relates to local air quality:  Policy BN9 – Planning for Pollution Control: ‘Proposals for new development which are likely to result in exposure to sources of pollution or risks to safety will need to demonstrate that they provide opportunities to minimise and where possible reduce pollution issues that are a barrier to achieving sustainable development and healthy communities, including maintaining and improving air quality, particularly in poor air quality areas, in accordance with national air quality standards and best practice.’ GUIDANCE 4.2.11. The following guidance documents have been used during the preparation of this assessment:  Design Manual for Roads and Bridges (DMRB) LA 105 Air Quality (Ref. 4.1);  Defra (2016) Local Air Quality Management Technical Guidance (LAQM.TG16) (Ref. 4.2);  Institute of Air Quality Management (2016) Guidance on the assessment of dust from demolition and construction (v1.1) (Ref. 4.3);  Environmental Protection UK/IAQM (2017) Land use planning and development control: Planning for air quality (v1.2) (Ref. 4.10); and  Technical guidance on detailed modelling approach for an appropriate assessment for emissions to air - AQTAG06 (2014) (Ref 4.18). STUDY AREA Construction Phase 4.2.12. The study area for the assessment of construction phase dust emissions and associated potential local air quality impacts is defined by the location of sensitive receptors identified within 350m of the site boundary and within 50m of construction traffic routes up to 500m from the site entrance, in accordance with the IAQM construction guidance (Ref. 4.3).

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Operational Phase 4.2.13. The study area for the assessment of operational phase impacts is governed by the ARN. Selected, relevant receptors within 200 m of the ARN are considered for assessment. The extent of the operational phase study area is presented in Figure 4.1: Study area, AQMA, and Affected Road Network (Volume IV of the ESA). 4.2.14. The study area encompasses two local authorities; Northampton Borough Council (NBC) and Daventry District Council (DDC). METHOD OF BASELINE DATA COLLATION 4.2.15. Traffic data provided by the project’s Design Team were screened in accordance with LA 105 (Ref 4.1) criteria (Section 4.1.9) to identify affected road links and the extent of the study area. 4.2.16. The final red line boundary for the Site was reviewed and used to inform the construction phase assessment outlined in Appendix 4.2: Construction Phase Assessment (Volume III of the ESA). This Site boundary can be seen Figure 4.1: Study area, AQMA, and Affected Road Network (Volume IV of the ESA) and subsequent figures. 4.2.17. The most recent Air Quality Annual Status Reports published by NBC (Ref 4.11) and DDC (Ref 4.12) were reviewed to establish baseline air quality conditions for the operational study area.

4.2.18. The Air Quality Annual Status Reports provide the annual mean NO2 concentrations at a number of monitoring sites relevant to the study area. In addition, the Defra AQMA interactive map (Ref 4.13) was used to identify any AQMAs of relevance to the study area.

4.2.19. A specific baseline NO2 monitoring survey was completed between November 2018 and February 2019 to inform the review of baseline conditions in the ES. These monitoring data were used to assess model performance as part of the atmospheric dispersion modelling study, in conjunction with 2018 local authority data provided by NBC and DDC and 2018 base year traffic data. 4.2.20. Background air pollutant concentrations corresponding to the 1km2 grid squares covering the operational study area were obtained from Defra’s published national pollutant mapping data (Ref 4.14). Background concentrations for 2018, 2021 and 2030 were obtained to represent current and future baseline air quality conditions across the study area within the assessment scenarios. 4.2.21. Ordnance Survey (OS) mapping and address layer data were used to identify potentially sensitive receptors in proximity to the Proposed Scheme and ARN. When visualised with OS mapping, the position of each human exposure can be determined, and this information was used to collate the locations of sensitive receptors for the local air quality assessment. The receptors represent locations where people are likely to be exposed for an appropriate averaging time, therefore gardens and playing fields are excluded for example as the 1-hour concentrations are not specifically modelled. These receptors are positioned at worst-case roadside locations and evenly spread throughout the study area. 4.2.22. Information on the locations of designated ecological sites was obtained from the Defra Magic

website (Ref 4.15). Background concentrations for NOx were obtained using the Defra background maps for the designated ecological sites, background deposition levels were obtained from the from the UK CBED model (Levy, et al., 2020).

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4.2.23. The latest national modelling undertaken by Defra (PCM modelling) to assess compliance with EU limit values includes several links located in the study area (as shown in Figure 4.7: PCM Network (Volume IV of the ESA)). PCM links are discussed further in Section 4.3 ASSESSMENT METHODOLOGY Construction Phase 4.2.24. The assessment of local air quality impacts due to the release of fugitive dust, including particulates

(PM10), during the construction phase has been informed by the methodology detailed in the IAQM guidance (Ref 4.3), with reference to LA 105 (Ref 4.1). 4.2.25. Full details of the construction assessment methodology are provided in Appendix 4.2: Construction Phase Assessment (Volume III of the ESA). 4.2.26. Information on the specific traffic management measures, the precise location of construction site entrances, and the precise number of vehicle movements related to construction were not available at the time of assessment. 4.2.27. However, estimates have been provided and the following have been assumed for the purposes of the assessment:  25 peak construction related two-way HDV movements per day2is anticipated, based on an assumed five-and-a-half-day week; and  These movements would be split between the north compound located off Sandy Lane and the south compound located off Road. 4.2.28. The criteria in LA 105 stipulate that further assessment of vehicle emissions is required where a change of 1,000 Annual Average Daily Traffic (AADT) movements or more is expected, or the heavy-duty vehicle (HDV) flow will change by 200 AADT or more. As the estimated peak construction traffic flow is below these criteria, further assessment of construction phase vehicle emissions has been scoped out of this assessment. 4.2.29. The assessment during the construction phase has therefore focussed on potential impacts associated with fugitive dust and particulate emissions from the following activities likely throughout the construction phase:  Demolition;  Earthworks;  Construction; and  Trackout (dust generating material which leaves the site via attachments to vehicle tyres). 4.2.30. For human receptors, amenity impacts from dust soiling and human health effects due to increases

in exposure to PM10 and PM2.5 have been assessed. For ecological receptors, potential harm to sensitive habitats and plant communities from dust deposition have been assessed. Factors including the scale and nature of activity, in addition to the sensitivity of the area, have been considered when assessing the risk of dust impacts.

2 Two-way vehicle movements incorporate each vehicle travelling to and travelling from the construction site.

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Significance Criteria 4.2.31. The significance of any dust emissions from the construction of the Proposed Scheme has been assessed in accordance with guidance provided by the IAQM (Ref. 4.3). 4.2.32. Step four of the IAQM guidance states that ’for almost all construction activity, the aim should be to prevent significant effects on receptors through the use of effective mitigation’. 4.2.33. The outcomes of the construction dust assessment are used to define appropriate mitigation measures to reduce the possibility of adverse effects from the construction phase of the Proposed Scheme and, as such, does not identify specific assessment significance criteria. 4.2.34. The IAQM guidance states in Section 2 in the terminology definition of effects that ‘in the context of construction impacts any effect will usually be adverse, however professional judgement is required to determine whether this adverse effect is significant based on the evidence presented’ and in the Section 1 introduction text that ‘it is anticipated that with the implementation of effective site-specific mitigation measures the environmental effect will not be significant in most cases’. Operational Phase 4.2.35. The Northamptonshire Strategic Transport Model (NSTM) was used as the basis to assess the impact of the Proposed Scheme on the operation of road network surrounding the Site in the planning application (June 2019). The NSTM informed the EIA process and the conclusions relating to air quality were reported in the 2019 ES in Chapter 6: Air Quality (Volume II of the 2019 ES). 4.2.36. The NSTM accounted for a range of committed developments within Northamptonshire County including all large proposed residential developments (by number of dwellings), major employment sites (by number of employees), and committed highway infrastructure schemes. 4.2.37. Following the submission of the planning application, several components of the NSTM have been updated which include:  A change in the scale of development for some of the committed developments captured within the NSTM;  Finalised designs for the road junctions associated with the proposed Dallington Grange Development located adjacent to Proposed Scheme; and  Updated traffic flow information based upon traffic survey data gathered during surveys in May 2019. 4.2.38. The local air quality assessment has focussed on the following scenarios, for which traffic data were provided to facilitate atmospheric dispersion modelling using Cambridge Environmental Research Consultants (CERC’s) ADMS-Roads v4.1.1 model:  Base / Verification Year (2018);  Do Minimum 2021 (Including Dallington Grange Residential Development);  Do Something 2021 (Including Dallington Grange Residential Development and Proposed Scheme);  Do Minimum 2031 (Including Dallington Grange Residential Development); and  Do Something 2031 (Including Dallington Grange Residential Development and Proposed Scheme). 4.2.39. Committed developments that are expected to influence local traffic flows have been accounted for in the growth factors applied to baseline traffic flows.

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4.2.40. Further information on the methodology utilised to generate traffic data is provided in the Proposed Scheme Transport Assessment (please refer to Appendix 3.11: Transport Assessment (Volume III of the ESA).

4.2.41. Emissions inventory databases for each pollutant (NOx, PM10, and PM2.5) were developed for all of the above scenarios using Defra’s emission factor toolkit (EFT v9.0) which succeeded EFT v8.0.1 in May 2019. EFT v9.0 accounts for vehicle flow characteristics, such as:  Link flow volumes as AADT, including percentage HDVs;  Link average speed (km/hr); and  Period breakdown (i.e. AM and PM peak, inter-peak and off-peak). 4.2.42. Each emissions database output for the respective scenario was input to the ADMS-Roads model to enable prediction of pollutant concentrations at the identified sensitive receptor locations. The modelling exercise utilised the following key inputs:  Pollutant emissions rates for each affected road link within the study area (g/km/s);  Geometry of each affected road link;  Hourly sequential meteorological data obtained from Bedford for 2018; and  Coordinates of each sensitive receptor at which the model calculated pollutant concentrations.

4.2.43. Verification of the ADMS-Roads model outputs was undertaken using the annual mean NO2 model

outputs for the base year (2018) and the 2018 annualised mean NO2 scheme-specific baseline monitoring data. This enabled appropriate model adjustment factors, derived with reference to LAQM.TG16, to be applied to model outputs to ensure the performance of the dispersion model was suitable within the context of the available monitoring data.

4.2.44. Verification of PM10 and PM2.5 has been completed using the same factor determined through

verification of NO2 concentrations, in accordance with LAQM TG16 technical guidance (Ref 4.2),

which states ‘…in the absence of any PM10 (and PM2.5) data for verification, it may be appropriate to

apply the road- NOx adjustment to the modelled road PM10/2.5’. 4.2.45. Further detailed information on the modelling process, input data and the model verification and adjustment procedure are presented in Appendix 4.4: Dispersion Model Approach and Verification (Volume III of the ESA). 4.2.46. The results of the atmospheric dispersion modelling at each identified receptor (as discussed in Section 4.5) has been compared to the respective air quality objective values, set for the protection of human health, and where applicable, ecosystems, to evaluate the potential for exceedances in all scenarios. Sensitivity Testing

4.2.47. Diffusion tubes have been used by WSP, NBC and DDC as an effective method of monitoring NO2 concentrations within Northampton and the surrounding areas. However, this equipment is affected by several sources of interference which can cause substantial under or overestimation (often referred to as ‘bias’).

4.2.48. As a result, when using NO2 diffusion tubes a quantification of the ‘bias’ of their diffusion tube measurements is required and an appropriate bias adjustment factor is applied to the annual mean if necessary. There are two methods of determining this bias adjustment factor:

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 Carry out a co-location study (in which the accuracy of the diffusion tubes is quantified by exposure alongside an automatic chemiluminescence analyser) and use the results to calculate a bias adjustment factor. Known as locally derived bias adjustment factors.  Use a combined bias adjustment factor, based on the result of many co-location studies (using the same laboratory and tube preparation method). Known as national bias adjustment factors. 4.2.49. NBC have applied a mixture of local and national bias adjustment factors to raw monitoring data over the last five reporting periods. During the consultation, NBC have requested that sensitivity testing is undertaken using monitoring data adjusted by both local and national bias adjustment factors during the verification process. 4.2.50. Full details are available in Appendix 4.4: Dispersion Model Approach and Verification (Volume III of the ESA). The sensitivity testing has been applied and reported for the receptors predicted to experience the largest pollutant concentrations, which can be found in Section 4.5 Supplementary Analysis. Significance criteria 4.2.51. The magnitude of change of predicted concentrations at each location, as a result of the Proposed Scheme, has been derived through analysis of the opening year (2021) Do Something versus Do Minimum scenario data. This has been replicated for 2031. 4.2.52. The significance of potential changes to local air quality has been determined in accordance with the criteria provided by IAQM (Ref 4.3) and in LA 105 (Ref 4.1)

4.2.53. LA 105 (Ref 4.1) sets out magnitudes of change in annual concentrations of NO2, PM10, PM2.5 to categorise a significant effect for receptors where the concentration of a pollutant is within 10% of the relevant objective with the Proposed Scheme. The magnitude of change criteria is presented in Table 4-4.

Table 4-4: Magnitude of Change Criteria

Magnitude of Change in Concentration Value of Change in Annual Average NO2 and PM10

Large (>4) Greater than 10% of the air quality objective (4µg/m3)

Medium (>2 to 4) Greater than 2µg/m3 but less than 10% of the objective (4µg/m3)

Small (>0.4 to 2) Greater than 1% of the objective (0.4µg/m3) but less than 5% of the objective (2µg/m3)

Imperceptible (≤ 0.4) Less than or equal to 1% of the objective (0.4 µg/m3)

4.2.54. Advice on the significance of local air quality effects of major highway schemes is presented in LA 105. The scope of this guidance includes the assessment of significant effects at representative human receptors for public exposure and designated ecosystems.

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4.2.55. Where LA 105 is applied, changes in pollutant concentrations greater than imperceptible (more than 0.4 µg/m³) at each identified receptor, based on the Do Minimum versus Do Something opening year (2021) and future year (2031) model results, are compared with guideline bands that inform the potential significance of the Proposed Scheme. The guideline band ranges as presented in Table 4- 5 set the upper level of likely non-significance and the lower level of likely significance. Between these two levels are the ranges where likely significance is more uncertain, and greater onus is afforded to professional judgement.

Table 4-5: Guideline to Number of Properties Constituting a Significant Effect

Magnitude of Change (µg/m3) Number of Receptors Demonstrating

Worsening of air quality that Improvement of air quality that already exceeds objective, risk of already exceeds objective, risks exceeding objective or creation of of exceeding objective or the new exceedances removal of existing exceedances

Large (>4) 1 to 10 1 to 10

Medium (>2 to 4) 10 to 30 10 to 30

Small (0.4 to 2) 30 to 60 30 to 60 4.2.56. Significant air quality effects are only identified for those receptors where air quality thresholds are exceeded or are at risk of being exceeded in either the Do Minimum and/or Do Something scenarios, as per LA 105. 4.2.57. Whilst the approach contained within LA 105 focusses on receptors already exceeding an annual mean objective, or within 10% of exceeding the objective, guidance for determining the impact of the operational phase of the Proposed Scheme on each of the individual local air quality sensitive receptors is provided by IAQM. Although LA 105 takes precedence, the IAQM guidance provides further supporting evidence to the judgment of significance. 4.2.58. The IAQM guidance describes the magnitude of incremental change (Do Minimum versus Do Something) in the pollutant concentration at each individual sensitive receptor as a proportion of a relevant air quality assessment level (AQAL). In this assessment, the AQALs are the annual mean

NO2, PM10 and PM2.5 objectives. The incremental change at each sensitive receptor is examined in the context of the total predicted annual mean concentration and its relationship with the AQAL as detailed in Table 4-6.

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Table 4-6: Impact Descriptors for Individual Receptors Relating to Annual Mean NO2, PM10

and PM2.5 Predicted Concentrations

Annual Mean % Change in concentration (Do Minimum – Do Something) relative to Air Concentration Quality Assessment Level (AQAL)*

1% 2-5% 6-10% >10%

≤75% of AQAL Negligible Negligible Slight Moderate

76-94% of AQAL Negligible Slight Moderate Moderate

95-102% of AQAL Slight Moderate Moderate Substantial

103-109% of AQAL Moderate Moderate Substantial Substantial

≥110% of AQAL Moderate Substantial Substantial Substantial

* AQAL in this assessment refers to the annual mean air quality objectives for NO2, PM10, and PM2.5 4.2.59. This approach allows an impact descriptor to be assigned to each receptor, with overall significance of the effects of any impacts assigned by professional judgement. Ecological Sensitive Receptors (Designated Sites) 4.2.60. The effect of changes of air pollutants on ecologically sensitive designated sites within the study area has been assessed in accordance with LA 105 (Ref 4.1). 4.2.61. Four designated sites were identified within 200m of the affected road network:  Upper Nene Valley Gravel Pits (Ramsar, SPA and SSSI);  Barnes Meadow and Kingsthorpe (Local Nature Reserves (LNR)); and  Berry Wood (Ancient Woodland). 4.2.62. . For each designated habitat, transect receptor points at 10m intervals were modelled, starting from the nearest point of the designated habitat to the road, up to a maximum distance of 200 m.

4.2.63. For each point along a transect, the road NOx concentration is converted to road NO2, for the base

year, and Do Minimum and Do Something in the opening year. The road NO2 is then converted to

dry nutrient nitrogen (N) deposition rate (kg N/ha/yr). Conversion rates of NO2 concentrations (1 µg/m3) to N deposition kg N/ha/yr are taken from the air quality advisory group guidance document AQTAG06 (Ref 4.18). 4.2.64. The road N deposition rate for the base year, Do Minimum and Do Something in the opening year is added to the background N deposition for each point along the transect. Background deposition levels were obtained from the from the UK CBED model (Levy, et al., 2020). 4.2.65. The impacts of air pollution on vegetation are assessed using two metrics: critical loads and critical levels (Ref 4.16):  Critical Loads are defined as " a quantitative estimate of exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge"

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 Critical levels are defined as "concentrations of pollutants in the atmosphere above which direct adverse effects on receptors, such as human beings, plants, ecosystems or materials, may occur according to present knowledge" 4.2.66. Critical loads are assigned to specific habitats, whereas critical levels cover broad vegetation types. The results were compared to the critical loads and critical levels for the relevant habitats, which are found on the APIS website (Ref. 4.16). APIS has critical loads for relevant habitats that relate to both eutrophication and acidification:  Eutrophication - Occurs in terrestrial ecosystems when the critical load for N is exceeded over a long period and the ability of the habitat to remove excess nitrogen through leaching, fixation or other means is decreased to the point where excess nutrient begins to accumulate. An excess level of nutrient N in such designated areas can cause slower growing species accustomed to nutrient poor habitats to be out competed by weed species that favour nutrient rich habitats. As such, designated habitats, and the fauna that depend upon them, can be highly affected by a change in species balance as a result of eutrophication.  Acidification - Occur from the deposition of oxidised N compounds as a result of a reduction in the ability of soil to neutralise acids. This can lead to a reduction in the breakdown of biological litter and an increase in the dominance of acid tolerant plant species as the soil pH drops. 4.2.67. An overall location plan for the designated sites is shown in Figure 4.5: Designated Ecological Sites (Volume IV of the ESA). Effect significance 4.2.68. The following terms have been used to define the significance of the effects identified and apply to both beneficial and adverse effects:  Major effect: where the Proposed Scheme could be expected to have a substantial improvement or deterioration on receptors;  Moderate effect: where the Proposed Scheme could be expected to have a noticeable improvement or deterioration on receptors;  Minor effect: where the Proposed Scheme could be expected to result in a perceptible improvement or deterioration on receptors;  Negligible: where no discernible improvement or deterioration is expected as a result of the Proposed Scheme on receptors; and  No change: where no change is expected because of the Proposed Scheme on receptors. 4.2.69. The significance presented in this assessment is in relation to criteria outlined in both LA 105 (Ref 4.1) and IAQM/EPUK (Ref 4.10). 4.3 BASELINE CONDITIONS 4.3.1. This section presents a summary of baseline conditions assessment across the study area, presented for each of the respective local authorities which the study area spans: Northampton Borough Council and Daventry District Council.

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EXISTING BASELINE Northampton Borough Council Local Air Quality Management 4.3.2. A review of the 2019 Air Quality Annual Status Report (Ref 4.11) found that Northampton Borough Council has designated seven AQMAs within their administrative area as a consequence of their local air quality review and assessment work. Of these AQMAs, three are located within the study area and a summary of the AQMA’s are detailed below:

 Northampton AQMA No.3 – declared for exceedance of the annual mean objective for NO2. An area encompassing a number of properties along St James Road, Weedon Road, Harlestone Road and adjoining streets.

 Northampton AQMA No.4 – declared for exceedance of the annual mean objective for NO2. This is the closest AQMA to the Site at approximately 1.3km to the east of the Site boundary and covers an area encompassing roads and properties on Kingsthorpe Grove, Harborough Road, Canford Terrace, Alexandra Terrace and Boughton Green Road.

 Northampton AQMA No.6 – declared for exceedance of the annual mean objective for NO2. An area encompassing a number of properties in or near Campbell Square at the junction of the A4500 Grafton Street and Regent Street in central Northampton. 4.3.3. The location and extent of these AQMA’s are shown in Figure 4.1: Study area, AQMA, and Affected Road Network (Volume IV of the ESA).

4.3.4. In 2015 a number of exceedances of the annual mean AQO for NO2 have been monitored at the following three junctions in the Northampton:  White Elephant Junction (Race Course/Kettering Road);  The Drapery and North Gate Bus Station area; and  Abington Square Area. 4.3.5. As a result, a public consultation took place in accordance with Defra policy guidance in December 2018/January 2019 on the proposed amalgamation of the existing 5 town centre AQMA’s to capture the new exceedance areas. Local Air Quality Monitoring

4.3.6. Northampton Borough Council monitors NO2 concentrations across the borough using both continuous and passive methods. This includes one continuous monitoring station and 76 diffusion tube sites deployed in 2018. 4.3.7. The Northampton Spring Park Automatic Urban and Rural Network (AURN) continuous monitoring

site is located approximately 0.4 km from the Proposed Scheme and monitors NO2. Annual mean

NO2 concentrations recorded at this location since inception in 2017 and 2018 are presented in 3 Table 4-7. The results show that NO2 concentrations are below the 40 µg/m annual mean objective by 70%.

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Table 4-7: Northampton Borough Council Automatic Monitoring Data

Site Name Site Type Pollutant Annual Mean Concentration (µg/m3)

2015 2016 2017 2018

Northampton Spring Park Urban Background NO2 -* -* 12.0 12.9

*Data unavailable

4.3.8. There are thirteen NO2 diffusion tube monitoring sites within 1.5km of the study area. The annual

mean NO2 concentrations recorded at these sites are presented in Table 4-8. The 2018 data in this table is adjusted using a local bias factor of 0.79, as presented in the 2019 Air Quality Annual Status Report (Ref 4.11).

Table 4-8: Northampton Borough Council Diffusion Tube Monitoring Data

3 Site Name Site Type Distance Annual Mean NO2 Concentration (µg/m ) from Site (km) 2015 2016 2017 2018 2019 (N/A) (N/A) (0.85 LR) (0.79 LB) (0.77 LB)

47, 48 & 49 Urban 0.4 12.7 14.9 15.9 13.1 15.6 Spring Rec Background Ground

50 Roadside 1.3 35.9 41.0 37.8 30.1 28.4 Harborough Rd 2

51 Roadside 1.3 36.7 36.1 36.9 29.6 25.5 Harborough Rd 3

52 Roadside 1.3 44.1 48.5 40.9 36.0 27.2 Harborough Rd 4

53 Roadside 1.3 44.8 45.0 48.7 35.7 32.4 Harborough Rd 5

54 Roadside 1.3 45.1 48.7 45.8 37.7 34.2 Harborough Rd 6

55 Roadside 1.3 40.7 44.4 46.1 34.4 27.7 Harborough Rd 7

56 Roadside 1.3 37.3 41.2 41.3 31.5 28.0 Harborough Rd 8

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3 Site Name Site Type Distance Annual Mean NO2 Concentration (µg/m ) from Site (km) 2015 2016 2017 2018 2019 (N/A) (N/A) (0.85 LR) (0.79 LB) (0.77 LB)

57 Roadside 1.3 45.9 62.7 59.7 47.1 41.4 Harborough Rd 9

59 Roadside 1.4 35.0 46.9 42.6 33.4 31.4 Harborough Rd 11

60 Roadside 1.4 46.3 46.8 49.1 36.5 27.6 Harborough Rd 12

61 Roadside 1.5 37.9 41.1 43.4 30.7 32.8 Kingsthorpe Grove 1

62 Roadside 1.5 32.6 38.8 33.4 26.1 30.3 Kingsthorpe Grove 2

Note: Exceedances of the air quality objective are highlighted in bold. LR = Local Roadside, LB = Local Background

4.3.9. The data in Table 4-8 show that 2018 annual mean NO2 concentrations from the study area exceeded the air quality objective at seven of the 13 sites between 2015 and 2018. All these exceedances are located within the Northampton AQMA No. 4. However only one exceedance is observed in 2018. 4.3.10. The closest monitors to the Site are urban background diffusion tubes 47, 48 & 49. The most recent

concentrations from this monitoring site are below the annual mean NO2 objective by 60%. Concentrations from this monitor are considered to be most representative of air quality conditions at the Site due to its proximity to the Proposed Scheme. PCM Model Links 4.3.11. Within Northampton Borough Council, there are 26 PCM links that overlap links included within the

study area. The predicted annual mean NO2 concentrations provided by the PCM model adjacent to these roads are presented in Table 4-9 for 2018, 2021 and 2030.

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Table 4-9: Northampton Borough Council Predicted Annual Mean NO2 Concentrations Adjacent to Road Links Relevant to the Proposed Schemed Obtained from Defra PCM Model for Years 2018, 2021 and 2030

3 Road Name Census ID Annual Mean NO2 Concentration (µg/m )

2018 2021 2030

A5095 26,539 25 22 15

47,958 20 18 13

A508 28,261 23 20 13

46,546 35 30 19

7,223 24 21 14

77,425 25 22 14

99,145 27 23 15

18,162 21 18 12

8,233 28 25 18

6,462 27 23 16

A5123 28,557 30 26 18

6,461 27 24 16

37,815 28 25 18

A43 8,447 41 35 23

A4500 17,938 29 27 17

74,775 35 30 21

27,922 28 24 16

A428 7,707 29 25 17

5,768 30 26 17

38,260 30 27 18

A5199 77,424 23 20 13

A5076 99,142 22 19 12

99,143 23 20 14

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3 Road Name Census ID Annual Mean NO2 Concentration (µg/m )

2018 2021 2030

38,054 33 28 18

99,107 31 27 17

56,468 36 31 20

4.3.12. The projected PCM model outputs shown in 4.3.13. Table 4-9 demonstrate that the annual mean NO2 concentrations in the 2018 base year, 2021 opening year and 2030 assessment year are predicted to be compliant with and below the respective EU limit value. Ecological Designations 4.3.14. The Defra Magic interactive map (Ref. 4.15) has identified four designated sites within 200 m of the affected road network with features sensitive to air quality, please refer to Table 4-10 and Figure 4.5: Designated Ecological Sites (Volume IV of the ESA). 4.3.15. The most appropriate and sensitive habitat has been assigned to each site for evaluation using the APIS website. Feature classifications are not available for LNR and Ancient Woodland Sites, therefore the most appropriate feature from Upper Nene Valley Gravel Pits has been used for the assessment, this is ‘Pluvialis apricaria - Golden Plover’ for LNR due to its grassland designation and ‘Alnus glutinosa-Urtica dioica woodland - Broad-leaved, mixed and yew woodland’ for the Ancient Woodland site.

Table 4-10: Designated Sites in Northampton Borough Council within 200m of the Study Area

Name Features Average Average Critical Load Critical Load for background background for Acidification NOx N Deposition Eutrophication (keq/ha/yr) concentration (kg N/ha/yr) (kg N/ha/yr) (µg/m3)

Upper Nene Pluvialis 19.8 19.9 20-30 MinCLminN: Valley Gravel apricaria- 0.223 Pits SSSI / Golden Plover MaxCLminN: Ramsar / SPA 0.438 MinCLMaxS: 0.45 MaxCLMaxS: 4.11 MinCLMaxN: 0.673 MaxCLMaxN: 4.548

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Name Features Average Average Critical Load Critical Load for background background for Acidification NOx N Deposition Eutrophication (keq/ha/yr) concentration (kg N/ha/yr) (kg N/ha/yr) (µg/m3)

Barnes Pluvialis 20.3 19.9 20-30 MinCLminN: Meadow LNR apricaria- 0.223 Golden Plover MaxCLminN: 0.438 MinCLMaxS: 0.45 MaxCLMaxS: 4.11 MinCLMaxN: 0.673 MaxCLMaxN: 4.548

Berry Wood Alnus 15.1 30.1 10-20 MinCLminN: Ancient glutinosa- 0.142 Woodland Urtica dioica MaxCLminN: woodland- 0.357 Broad-leaved, MinCLMaxS: mixed and 0.934 yew woodland MaxCLMaxS: 10.648 MinCLMaxN: 1.076 MaxCLMaxN: 10.79

Kingsthorpe Pluvialis 17.7 17.6 20-30 MinCLminN: LNR apricaria- 0.223 Golden Plover MaxCLminN: 0.438 MinCLMaxS: 0.45 MaxCLMaxS: 4.11 MinCLMaxN: 0.673 MaxCLMaxN: 4.548

The NOx concentration and N-deposition rates are based on a 3-year mean 2015-17

3 4.3.16. Background NOx concentrations are well below the annual mean objective (30µg/m ). 4.3.17. At the Berry Wood Ancient Woodland site, Alnus glutinosa-Urtica dioica woodland - Broad-leaved, mixed and yew woodland has a specified critical load range of 10-20 kg N/ha/yr and a reported average background deposition rate of 30.1 kg N/ha/yr, which exceed its respective critical load range.

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Daventry District Council Local Air Quality Management 4.3.18. The 2017 Air Quality Annual Status Report (Ref 4.12) completed in February 2018 found that there are currently no AQMAs designated within the Daventry district. The collective monitoring data

across the district has shown minor increases and decreases in NO2 over the five-year period reviewed. None of the increases and decreases were identified as being significant and warranted no further action. 4.3.19. The proposed roundabout at the A5199/Brampton Lane junction a Boughton Crossing is a key focus area for DDC who require sustainable design to avoid the potential for an AQMA declaration at this

location. In the 2019 ES, the greatest deterioration in annual average NO2 concentration was predicted at this location (15.5 µg/m3) which corresponds to a substantial adverse impact. However, although an exceedance of the annual mean objective was not predicted, a Health Distributional Impacts assessment to inform a damage cost calculation was proposed as mitigation.

4.3.20. Results of Proposed Scheme specific monitoring of NO2 at the Boughton Crossing are shown in Table 4-13. Local Air Quality Monitoring 4.3.21. Daventry District Council monitored air quality across the district using passive diffusion tubes at 26 sites during 2016. Daventry District Council did not undertake any continuous monitoring in 2016 or

monitoring of PM10 or PM2.5.

4.3.22. There are four diffusion tube monitoring sites within 1.5km of the study area. The annual mean NO2 concentrations recorded at these sites between 2015 and 2016 are presented in Table 4-11.

Table 4-11: Daventry District Council Diffusion Tube Monitoring Data (µg/m3)

Diffusion Location Site Type Annual Mean Concentration (µg/m3) Tube ID

2015 2016 2017* 2018*

N2 Broughton Kerbside 18.7 20.4 -- -- Road

N5 Park View Kerbside 26.0 26.5 -- --

N7 Post Office Roadside 22.0 23.8 -- --

N8 Church Street Suburban/Rural 15.4 17.4 -- --

* Data unavailable

4.3.23. The results indicate that annual mean concentrations of NO2 have not exceeded the annual mean air quality objective over the period reviewed. PCM Model Links 4.3.24. Within Daventry District Council, there are four PCM links that overlap links included within the study

area. The predicted annual mean NO2 concentrations provided by the PCM model adjacent to these roads are presented in Table 4-12 for 2018, 2021 and 2030.

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Table 4-12 – Daventry District Council Predicted Annual Mean NO2 Concentrations Adjacent to Road Links Relevant to the Proposed Schemed Obtained from Defra PCM Model for Years 2018, 2021 and 2030

3 Road Name Census ID Annual Mean NO2 Concentration (µg/m )

2018 2021 2030

A5199 77,424 23 20 13

A508 77,425 25 22 14

A428 77,422 25 22 14

A5076 99,142 22 19 12

4.3.25. The projected PCM model outputs shown in Table 4-12 demonstrate that the annual mean NO2 concentrations in the 2018 base year, 2021 opening year and 2030 assessment year are predicted to be compliant with and below the respective EU limit value. Ecological Designations 4.3.26. There are no designated sites within 200 m of the study area contained within Daventry District Council’s jurisdiction with features sensitive to air quality. PCM Model Links

4.3.27. Modelled concentrations of annual mean NO2 (Figure 4.11: Annual Mean NO2 DM21 (Volume IV

of the ESA) and Figure 4.14: Annual Mean NO2 DS21 (Volume IV of the ESA)) corresponding to the PCM links in Northampton Borough Council’s and Daventry District Council’s jurisdiction shown in Figure 4.7: PCM Network (Volume IV of the ESA), indicate that no exceedances at the PCM links are likely in either 2021 or 2030. As such, it was decided not to carry out further detailed assessment of Northampton Borough Council or Daventry District Council PCM links. However, a semi-qualitative discussion of the impact of the Proposed Scheme on PCM links is included in Section 6.6. Proposed Scheme Specific Air Quality Monitoring

4.3.28. A Proposed Scheme specific NO2 baseline monitoring programme was completed to supplement the local authority monitoring results and inform baseline conditions for the study area. The three-month programme began in November 2018 and ended in February 2019 and comprised 11 roadside and urban background monitoring locations. The locations of the monitoring sites selected are shown in Figure 4.2: Scheme Specific Local Authority Monitoring (Volume IV of the ESA) and detailed in Appendix 4.3: Scheme Specific Monitoring (Volume III of the ESA).

4.3.29. The three months of data were used to derive annualised mean NO2 concentrations at each monitoring location for the base year (2018). Details of the annualisation calculations are provided in Appendix 4.3: Scheme Specific Monitoring (Volume III of the ESA). 4.3.30. The 2018 annualised data are presented in Table 4-13 and were used to facilitate verification of modelled predictions, as detailed in Appendix 4.3: Scheme Specific Monitoring (Volume III of the ESA).

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Table 4-13: Summary of the Scheme Specific Baseline Annualised Mean NO2 Monitoring Results

Site ID Site X Y Site Name 2018 Classification Annualised Mean NO2 Concentration (µg/m3)

Spring Recreation Ground, 16.3 NRR 1 Roadside 474067.8 264238.3 Welford Road

NRR 2 Roadside 473681.1 265252.1 Boughton Crossing 14.4

Northampton Road/ 16.5 NRR 3 Roadside 472982.0 266313.2 Road Junction, Chapel Brampton

Harlestone Road, Church 13.5 NRR 4 Roadside 472154.2 265951.6 Brampton

Urban 14.3 NRR 5 471945.6 263335.8 Lodge Way Background

Harlestone Road 15.9 NRR 6 Roadside 471247.7 263450.7 Roundabout

Harlestone Road/Quarry 15.2 NRR 7 Roadside 471640.7 262900.8 Road

St Andrews Church, 11.0 NRR 8 Roadside 473057.0 261938.6 Harlestone Road

Park Drive/Mill Lane 15.8 NRR 9 Roadside 473969.5 262381.8 Roundabout

Harlestone Road / Whites 18.3 NRR 10 Roadside 471315.9 263387.3 Lane

NRR 11 Roadside 470358.0 264737.0 A428/Church Lane 13.6

3 3 4.3.31. The 2018 annualised mean concentrations for NO2 ranged between 11.0 µg/m and 18.3 µg/m ,

thus indicating that existing NO2 levels are under 50% of the annual mean air quality objective. Mapped Background Concentrations 4.3.32. Background pollutant values are based on the 1 km x 1 km grid squares encompassing the study area as derived from the Defra background maps (Ref. 4.14) and cover all years between 2017 and 2030 inclusive. 4.3.33. For the purposes of reviewing the existing background and predicted future background levels, the

maximum, minimum and average background annual mean concentrations of each pollutant (NOx, 2 NO2, PM10 and PM2.5) based on the 1km grids encompassing the study area, are presented in Table 4-14.

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4.3.34. Relevant road sector contributions were removed from the background values to ensure that ‘double counting’ of vehicle emissions from the same roads within the study area did not occur.

Table 4-14: Defra mapped Background Annual Mean Concentrations for each Pollutant in Base (2018), Opening (2021) and Future (2031) Years

Pollutant 2018 Background 2021 Background 2031 Background Concentrations (µg/m3) Concentrations (µg/m3) Concentrations (µg/m3)

Max Min Average Max Min Average Max Min Average

NO2 13.0 6.4 9.5 11.9 5.8 8.5 10.6 4.7 7.0

NOx* 17.9 8.4 12.6 16.2 7.5 11.3 14.3 6.0 9.1

PM10 17.3 12.5 14.4 17.0 12.3 14.2 16.8 12.0 14.0

PM2.5 11.8 8.6 9.8 11.6 8.4 9.5 11.3 8.1 9.3

* Set for the protection of vegetation and ecosystems 4.3.35. The predicted current and future background concentrations presented in Table 4-14 are well below 3 3 the respective health-based annual mean objective values for NO2 (40 µg/m ), PM10 (40 µg/m ) and 3 3 PM2.5 (25 µg/m ). Similarly, the annual mean NOx objective value (30 µg/m ) set for the protection of vegetation and ecosystems, is not predicted to be exceeded. 4.3.36. The Defra mapped background concentrations were selected to represent background air quality at the Site instead of urban background monitoring. This approach was taken because the background monitored concentrations (Northampton Borough Council, 2015-2018, and the scheme specific urban background site (Table 4-13)) were consistent with the background mapped concentrations for the corresponding year, and it enabled a variable background to be applied at each receptor. 4.3.37. In Table 4-7, the closest urban background site to the Proposed Scheme, Northampton Spring Park, 3 measures a concentration of 12.9 µg/m for NO2 in 2018, whilst the urban background site included 3 in the scheme specific monitoring, NRR5, measures a concentration of 14.3 µg/m for NO2 in 2018 (Table 4-13). These measurements are shown to be consistent with the Defra mapped background concentrations in Figure 4.3: Defra background concentration 2018 - NOx (Volume IV of the

ESA) and Figure 4.4: Defra background concentration 2018 – NO2 (Volume IV of the ESA) Sensitive Receptors 4.3.38. Sensitive receptors are locations in which the public or sensitive ecological habitats may be exposed to pollutants resulting from activities associated with the Proposed Scheme. These will include

locations sensitive to an increase in dust deposition and PM10 exposure as a result of on-site construction activities, and locations sensitive to exposure to gaseous pollutants emitted from the exhausts of construction and operational traffic associated with the Proposed Scheme. Construction Phase 4.3.39. Existing residential areas are located within 350 m of the Site boundary and approach roads. As such, a construction dust assessment has been conducted with reference to IAQM guidance (Appendix 4.2: Construction Phase Assessment (Volume III of the ESA)).

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4.3.40. Distance bandings contained within Table 4.2-2, Table 4.2-3 and Table 4.2-4 of Appendix 4.2: Construction Phase Assessment (Volume III of the ESA) were analysed based on the Proposed Scheme alignment to identify potentially sensitive receptors. The number and location of existing ‘human’ receptors within each band is detailed in Table 4-15.

Table 4-15: Receptor Count Within 350m of Likely Construction Activities

Distance from Site Sensitive Receptor Count Boundary (m) Residential Educational Medical Total

<20 1 0 0 1

20-50 98 0 0 98

50-100 121 0 0 121

100-350 790 0 0 790

4.3.41. The highest risk receptors in terms of sensitivity are those that are downwind and within 50m of potential dust-generating construction activities. A wind rose derived from data recorded at Bedford for the year of 2018 demonstrates that the prevailing wind is from south west. Therefore, those receptors to the north east of, and within proximity to the construction activities are more likely to be affected by fugitive dust releases. 4.3.42. A wind rose showing the recorded wind speed and direction data is presented in Appendix 4.4: Dispersion Model Approach and Verification (Volume III of the ESA). 4.3.43. There are no statutory designated ecological sites within 50m of the Site boundary, therefore, as recommended by guidance from the IAQM (Ref 4.3), ecological sites have not been considered as part of the construction phase dust assessment. Operational Phase 4.3.44. Locations that are sensitive to pollutants emitted from engine exhausts include places where members of the public are likely to be regularly present over the period of time prescribed in the AQS. For instance, on a footpath where exposure will be transient (for the duration of passage along that path), comparison with a short-term standard (i.e. 15-minute mean or 1-hour mean) may be relevant. At a school or adjacent to a private dwelling, where exposure may be for longer periods, comparison with a long-term standard (such as 24-hour mean or annual mean) may be more appropriate. Box 1.1 of LAQM.TG16 (Ref. 4.2) provides examples of the locations where the air quality objectives should/should not apply. 4.3.45. LA 105 (Ref 4.1) states ‘There should be no need to model all receptors within 200 m, or an excessive number of receptors in the same area, to determine whether there is likely to be any exceedances in the do minimum or do something scenarios.’. In this assessment, all receptors within 50m of the affected road network have been modelled, to represent worst-case locations for all receptors identified.

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4.3.46. Receptors within 20m of the roadside are likely to experience the largest change in pollutant concentrations due to changes in traffic flows. Furthermore, a study carried out by Air Quality

Consultants (Ref 4.17) entitled NO2 Concentrations and Distance from Roads states ‘It is usually acknowledged that beyond 50m from the road, concentrations approach background levels’. 4.3.47. A total of 6,425 relevant receptors were identified within 50 m of the roads making up the local air quality assessment study area. The number of receptors within and outside of the relevant AQMA’s is presented in Table 4-16 and the locations of each receptor are depicted on Figure 4.6: Residential and Ecological Receptors (Volume IV of the ESA). These also include proposed receptors for the Dallington Grange committed development, which will produce receptors within 50m of the study area identified.

Table 4-16: Identified Sensitive Receptors within relevant AQMA’s

Types No. of Receptors

Proposed Receptors 133

Within AQMA 540

Outside of AQMA 5,885

Total 6,425 FUTURE BASELINE 4.3.48. The future baseline environment was considered to understand the likely change in annual mean concentrations in the long term, without the Proposed Scheme. 4.3.49. The Do-Minimum traffic data provided by the design team were appropriate for use in assessing the future baseline, given that the Proposed Scheme flows are not included. 4.3.50. The change in Do-Minimum local air quality conditions across the study area was considered at all identified receptors between the following scenarios, using predicted air quality pollutant concentrations derived from the traffic data provided:  Base Year (2018);  Do-Minimum (2021); and  Do-Minimum (2031). 4.3.51. Annual mean pollutant concentrations relating to each of the Do-Minimum scenarios were predicted across the study area at all 6,425 receptors and the change in concentration calculated. The maximum concentration of all predicted receptor values for each pollutant and scenario are presented in Table 4-17.

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Table 4-17: Evolution of the Baseline Environment Results Based on Maximum Predicted Values across the Study Area-2018-2031

Pollutant Predicted Maximum Annual Mean Value Change in Concentration Objective (µg/m3) (µg/m3)

Base 2018 DM 2021 DM2031* 2018-2021 2021-2031

NO2 48.0 43.4 27.6 -4.6 -15.8 40

PM10 22.2 21.5 21.6 -0.7 +0.1 40

PM2.5 13.9 13.3 13.2 -0.6 -0.1 25

All values given to 1 decimal place * Based on 2030 vehicle emissions factors provided by Defra EFT v9.0

4.3.52. There are no predicted exceedances of the annual mean objective for PM10 and PM2.5.

4.3.53. There are predicted exceedances of the annual mean objective for NO2 in the baseline and Do-Minimum (2021) at roadside sensitive receptors within the study area. However, the maximum annual mean predicted baseline concentrations are expected to decrease across the study area over the 13-year period for all pollutants. The Do-Minimum (2031) maximum modelled concentration is under the objective. 4.4 EFFECTS ARISING DURING CONSTRUCTION PRIMARY MITIGATION MEASURES 4.4.1. No embedded (primary) mitigation measures have been identified at this stage. ASSESSMENT OF IMPACTS AND EFFECTS 4.4.2. Construction works have the potential to give rise to dust and particulate matter generation during earthworks and general construction activities, as well as from the trackout of dust material by vehicles onto public highways. 4.4.3. Dust emissions can cause annoyance through the soiling of buildings and surfaces and/or adversely impact human and ecological health. 4.4.4. Major construction activities that are likely to be required during construction phase of the Proposed Scheme will include the following:  site clearance (assessed as earthworks and demolition as appropriate);  topsoil strip (assessed as earthworks);  excavation (assessed as earthworks);  landscaping (assessed as earthworks and construction as appropriate);  material import/export (assessed as trackout);  temporary stockpile of resources (assessed as construction, potentially dusty materials);  construction of contractor site compounds, utility diversion and access points (assessed as trackout);  construction of road (assessed as construction); and  construction of an attenuation basin and flood mitigation bunds (assessed as earthworks).

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4.4.5. The main potential air quality impacts that may arise from the aforementioned activities are:  dust deposition, resulting in the soiling of surfaces;  dust plumes, affecting visibility and amenity; and

 elevated ambient PM10 concentrations due to fugitive dust releases. 4.4.6. The potential for sensitive receptors to be affected is dependent on the scale and locations of the dust generating activities, the nature of the activity, and local meteorological conditions when the activity is taking place. 4.4.7. The nearest sensitive residential receptors are located within 20m and upwind of potential dust- generating construction activities. 4.4.8. As the precise location of dust generating activities within the construction site is not known, a conservative approach has been taken assuming that these activities could occur up to the Site boundary. A wind rose showing the recorded data is presented in Appendix 4.4: Dispersion Model Approach and Verification (Volume III of the ESA). 4.4.9. The effects of construction dust generated during dry conditions could lead to annoyance through

dust deposition and also localised increases in PM10 concentrations with the potential to adversely

impact human health. The maximum background annual mean PM10 concentration for the construction study area, as predicted by Defra, is 13.1 μg/m3 (2018), which is well below the annual mean objective value of 40 μg/m3. Therefore, it is unlikely that the short-term construction operations would cause the daily (50 µg/m3) or annual mean (40 µg/m3) objective value to be either approached or exceeded at sensitive receptors near to the construction area. 4.4.10. The overall risk of adverse construction dust impacts occurring; namely annoyance due to soiling (deposition) and impacts to human health, in the absence of mitigation, is detailed in Appendix 4.2: Construction Phase Assessment (Volume III of the ESA) and has been undertaken with reference to the IAQM guidance document (Ref 4.3). 4.4.11. This identified that there is a high risk of dust soiling impacts associated with earthwork activities and a medium to low risk associated with construction and trackout. There is a low to negligible risk of health impacts from increases in particulate matter concentrations. However, through good site practice and the implementation of suitable mitigation measures, the effect of dust and particulate matter releases would be negligible.

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MITIGATION MEASURES 4.4.12. The recommended mitigation measures for the construction phase focus on controlling fugitive releases of construction phase dust and should be implemented by the contractor through the Construction Environmental Management Plan (CEMP). However, the development of the measures is intended to be flexible and advisory and therefore the specific measures to be adopted will be discussed and finalised with the local EHO prior to implementation. 4.4.13. The CEMP will build on the framework for environmental management and mitigation measures committed to within the Outline CEMP (Appendix 3.1: Outline CEMP (Volume III of the 2019 ES). The CEMP will provide assurance to the decision maker and stakeholders that appropriate measures for preventing and reducing environmental effects will be adopted during the construction of the Proposed Scheme. The measures include, but may not be limited to:  dust generating activities (e.g., cutting, grinding and sawing) will be minimised and weather conditions considered prior to conducting potentially dust emitting activities;  fine material will not be stockpiled to an excessive height in order to prevent exposure to wind and/ or dust nuisance;  roads and accesses will be kept clean;  where possible, plant will be located away from Site boundaries close to residential areas;  water will be used as a dust suppressant, where applicable;  drop heights of material will be kept to a minimum;  distances from crushing plant to stockpiles will be kept to the minimum practicable to control dust generation associated with the fall of materials;  skips will be securely covered;  soiling, seeding, planting or sealing of completed earthworks will be completed as soon as reasonably practicable following completion of earthworks;  dust suppression and the maintenance of the surface of access routes will be appropriate to avoid dust as far as practicable, taking into account the intended level of trafficking;  wheel wash facilities at major site exits to minimise trackout of dust;  material will not be burnt on site;  engines will be switched off when not in operation;  daily on-site and off-site inspections will be undertaken, where receptors (including roads) are nearby to monitor dust. The inspection results should be recorded and made available to the local authority when asked. This should include regular dust soiling checks of surfaces such as street furniture, cars and window-sills within 100m of site boundary; and  the frequency of site inspections should be increased when activities with a high potential to produce dust are being carried out and during prolonged dry or windy conditions. 4.4.14. The CEMP will stipulate the following to ensure the mitigation is implemented effectively, continually monitored and updated accordingly:  Identification of a nominated Environmental Site Manager.  Notification procedures where potentially significant dust generating activities are required.  Method statements for the control of dust in such locations and complaint receipt.  Management procedures to ensure issues are addressed should they be raised by the public.

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SUMMARY OF LIKELY RESIDUAL SIGNIFICANT EFFECTS 4.4.15. With the appropriate implementation of the mitigation measures, the risk of local dust impacts at sensitive receptors is considered to be negligible with respect to local air quality. CUMULATIVE ASSESSMENT Cumulative Effects 4.4.16. No intra-project cumulative effects are predicted relating to air quality. In-Combination Effects 4.4.17. The following committed developments have the potential to cause cumulative construction effects in combination with the construction of the Proposed Scheme:  Dallington Grange Residential Development (n/2014/1429 – Northampton Borough Council) – outline planning permission granted in October 2018  Buckton Fields (DA/2011/0666 – Daventry District Council) – approval in 2014 for the eastern phase and in 2018 for the western phase)  Welford Road (DA/2014/0521 – Daventry District Council) – reserve matters application. 4.4.18. The Dallington Grange Residential Development is located directly south east of the Proposed Scheme while both the Buckton Fields and Welford Road developments are located to the east, off Welford Road. 4.4.19. According to the IAQM guidance (Ref. 4.3), construction impacts can occur up to 350 m (buffer zone) from a site boundary. Potential cumulative construction impacts can occur where this buffer zone overlaps with the buffer zone of other committed developments. This overlap occurs at the following properties overlapping with:  The Dallington Grange Residential Development • Swale Drive, Kings Heath • Nene Drive, Kings Heath • Nene Place, Kings Heath • Kenstone Close, off Welford Road • Redland Drive, off Welford Road • Properties on Grasscroft, off Welford Road; and • Grovebury Dell, off Welford Road  The Buckton Fields/Welford Road Development • The Avenue, off Welford Road • Fairmead Rise, off Welford Road; and • Cedrus Court, off Welford Road. 4.4.20. Mitigation measures to reduce potential cumulative effects in these areas are contained within the Outline CEMP (Appendix 3.1: Outline CEMP (Volume III of the ESA). Full details of the mitigation measures for dealing with air quality impacts should be included in the full CEMP. 4.4.21. All of the committed developments will be subject to the mitigation controls outlined in the respective CEMP which will be subject to approval by the planning authority. Therefore, all cumulative construction phase effects can be expected to be negligible.

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4.5 EFFECTS ARISING FROM OPERATION PRIMARY MITIGATION MEASURES 4.5.1. During the engineering design of the Proposed Scheme, due consideration has been given to measures that can be incorporated to minimise potential air quality impacts. The route alignment adopts the most westerly line that it can, maximising the distance between the Proposed Scheme and residential areas to the east (those areas accessed off Welford Road). ASSESSMENT OF IMPACTS AND EFFECTS 4.5.2. This section includes the results of local air quality predictions made using monitoring data which has been adjusted using a local bias adjustment factor of 0.79 in accordance with the findings in Appendix 4.4: Dispersion Model Approach and Verification (Volume III of the ESA). Also included within the results are:  Results of a sensitivity testing exercise in which the model results are processed using historical local and national bias adjustment factors as reported in the technical paper for Defra by Bureau Veritas.  Detailed description of the likely air quality impacts in key focus areas raised by the DDC and NBC EHOs during the consultation process. 4.5.3. These results are reported in the section Supplementary Analysis and are used to inform the overall assessment of significance of the Proposed Scheme. 4.5.4. A total of 6,425 relevant receptors were selected for inclusion in the atmospheric dispersion modelling assessment, most of which are situated in proximity to the ARN (see Figure 4.6: Residential and Ecological Receptors (Volume IV of the ESA)) and representative of sensitive

exposure to potential change in concentrations of NO2, PM10 and PM2.5. Opening Year 2021

4.5.5. A summary of the predicted annual mean NO2, PM10 and PM2.5 concentrations of the considered receptors across the study area for the opening year (2021) assessment is presented in Table 4-18.

Table 4-18: Summary of Predicted Annual Mean NO2, PM10 and PM2.5 Concentrations at Sensitive Locations in Base (2018) and Opening Year (2021)

Parameter NO2 PM10 PM2.5

Annual Mean 40µg/m3 40µg/m3 25µg/m3 Objective

Number of Base Exceedance 36 0 0 exceedances of (2018) respective objective by scenario Do Minimum 3 0 0 Exceedance (2021)

Do Something 0 0 0 Exceedance (2021)

Removed 3 0 0 Exceedances

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Parameter NO2 PM10 PM2.5

Annual Mean 40µg/m3 40µg/m3 25µg/m3 Objective

New Exceedances 0 0 0

Total number of Improvement in 4,698 4,672 4,677 Properties Concentration

No Change in 36 0 0 Concentration

Deterioration in 1,558 1,620 1,615 Concentration

Do Something-Do Maximum -9.5 -2.2 -1.2 Minimum Annual Improvement Mean Change (µg/m3) Maximum +15.9 +4.2 +2.4 Deterioration

Total Receptors 6,425 6,425 6,425

Ratio (Improvement to Deterioration) 3.0 2.9 2.9

Annual Mean NO2 Concentrations 4.5.6. Of the 6,425 modelled receptor locations, there are predicted to be exceedances of the annual

mean NO2 objective in the base and Do Minimum scenarios. There are predicted to be 36 exceedances in the base year and 3 in the Do Minimum scenario. The highest concentrations are predicted at Receptor R1316, where a concentration of 48.0µg/m3 is predicted in the ‘base year’ scenario. Receptor R1316 is located on Mill Lane within Northampton AQMA No.4. 4.5.7. In the base year, the majority of exceedances are concentrated at properties in or adjacent to the three AQMA’s highlighted in Section 4.3, the other exceedances are located on the A428 west of

Dallington Park (as shown in Figure 4.8: Annual Mean NO2 Base (Volume IV of the ESA)). In the Do Minimum scenario, three exceedances located within Northampton AQMA No.4 but no

exceedances are predicted in the Do-Something scenario. (Figure 4.11: Annual Mean NO2 DM21

(Volume IV of the ESA) and Figure 4.14: Annual Mean NO2 DS21 (Volume IV of the ESA)). This is primarily due to the reductions in future emissions predicted by EFT v9.0 which are greater than the increases caused by predicted baseline and committed development traffic growth and scheme generated traffic.

4.5.8. The majority of improvements in annual NO2 mean concentrations are predicted to occur at properties within or adjacent to the three AQMA’s highlighted in Section 4.3. The maximum improvement (9.5 µg/m3) is predicted at Receptor R2956 on the A428 in Lower Harlestone. This is due to a reduction in traffic flows along this route in the Do Something scenario.

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4.5.9. Conversely, the locations predicted to experience a worsening in annual mean NO2 concentrations are located adjacent to new road links and in close proximity to the Proposed Scheme where air pollution is currently well dispersed. The greatest worsening is predicted at Receptor R5403 (15.9 µg/m3) on Boughton Crossing which is on the north-east boundary of the Proposed Scheme,

adjacent to A5199 Welford Road as shown in Figure 4.17: Change in Annual Mean NO2 21 (Volume IV of the ESA).

4.5.10. Overall, the Proposed Scheme is predicted to cause improvements in annual mean NO2 at 4,698 properties, deteriorations at 1,558 properties and no change at 36 properties. Overall, there is

predicted to be three times as many improvements as deteriorations in annual mean NO2 and an improvement at every identified residential receptor within Northampton’s AQMAs.

Hourly Mean NO2 Concentrations

3 4.5.11. The annual mean NO2 concentrations predicted by the model were all below 60 µg/m and,

therefore, hourly mean NO2 concentrations are unlikely to cause a breach of the hourly mean objective. This is in line with the guidance provided within LAQM.TG16 (Ref 4.2), which states ‘Previous research carried out on behalf of Defra and the Devolved Administrations identified that

exceedances of the NO2 1-hour mean are unlikely to occur where the annual mean is below 60 µg/m3’.

Annual Mean PM10 Concentrations

4.5.12. There are predicted to be no exceedances of the annual mean PM10 in either the base, Do Minimum

or Do Something scenario (Figure 4.9: Annual Mean PM10 Base (Volume IV of the ESA), Figure

4.12: Annual Mean PM10 DM21 (Volume IV of the ESA) and Figure 4.15: Annual Mean PM10 DS21 (Volume IV of the ESA)). The highest concentrations are predicted at Receptor R1316 (on Mill Lane within Northampton AQMA No.4), where a concentration of 22.2 µg/m3 is predicted in the

‘base year’ scenario. This is under 56% of the annual mean objective for PM10.

4.5.13. The majority of improvements in annual PM10 mean concentrations are predicted to occur at properties within or adjacent to the three AQMA’s highlighted in Section 4.3. The maximum improvement is predicted at Receptor R2956 (2.2 µg/m3) on the A428 in Lower Harlestone. This is due to a reduction in traffic flows along this route in the Do Something scenario.

4.5.14. Conversely, the locations predicted to experience a worsening in annual mean NO2 concentrations are located adjacent to new road links and in close proximity to the Proposed Scheme, as shown in

Figure 4.18: Change in Annual Mean PM10 21 (Volume IV of the ESA). The greatest worsening is predicted at Receptor R5403 (4.2 µg/m3) on Boughton Crossing which is on the north-east boundary of the Proposed Scheme, adjacent to A5199 Welford Road.

4.5.15. Overall, the Proposed Scheme is predicted to cause improvements in annual mean PM10 at 4,672 properties and deteriorations at 1,620 properties.

Daily Mean PM10 Concentrations

4.5.16. Exceedances of the 24-hour mean objective for PM10 are unlikely if the annual mean concentration 3 is below 32 µg/m . Given that all predicted annual mean PM10 values are below this level, exceedances of the 24-hour objectives are very unlikely.

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Annual Mean PM2.5 Concentrations

4.5.17. There are predicted to be no exceedances of the annual mean PM2.5 in either the base, Do Minimum

or Do Something scenario (Figure 4.10: Annual Mean PM2.5 Base (Volume IV of the ESA), 4.13:

Annual Mean PM2.5 DM21 (Volume IV of the ESA) and Figure 4.15: Annual Mean PM2.5 DS21 (Volume IV of the ESA)). The highest concentrations are predicted at Receptor R1316 (on Mill Lane within Northampton AQMA No.4), where a concentration of 13.9 µg/m3 is predicted in the

‘base year’ scenario. This is under 56% of the annual mean objective for PM10.

4.5.18. The majority of improvements in annual NO2 mean concentrations are predicted to occur at properties within or adjacent to the three AQMA’s highlighted in Section 4.3. The maximum improvement is predicted at Receptor R2956 (1.2 µg/m3) on the A428 in Lower Harlestone. This is due to a reduction in traffic flows along this route in the Do Something scenario.

4.5.19. Conversely, the locations predicted to experience a worsening in annual mean NO2 concentrations are located adjacent to new road links and in close proximity to the Proposed Scheme, as shown in

Figure 4.19: Change in Annual Mean PM2.5 21 (Volume IV of the ESA). The greatest worsening is predicted at Receptor R5403 (2.4 µg/m3) on Boughton Crossing which is on the north-east boundary of the Proposed Scheme, adjacent to A5199 Welford Road.

4.5.20. Overall, the Proposed Scheme is predicted to cause improvements in annual mean PM10 at 4,677 properties and deteriorations at 1,615 properties. Magnitude of Change

4.5.21. The predicted magnitude of change in annual mean NO2, PM10 and PM2.5 concentrations across all modelled relevant receptors is summarised in Table 4-19. The changes have been calculated with reference to the magnitude of change criteria provided in LA 105.

4.5.22. For annual mean NO2, the vast majority of receptors experience a predicted decrease in concentration. A large change (+/->4 µg/m3) is predicted at 75 of the receptors. With the Proposed

Scheme in place, no receptors are predicted to be above the NO2 annual mean objective.

4.5.23. For both PM10 and PM2.5, the annual mean changes at receptors predominately sit within the 0 to 0.4 µg/m3 decrease range.

Table 4-19: Predicted Magnitude of Change in Annual Mean Concentrations in the Opening Year (2021)

Change in annual mean NO2 PM10 PM2.5 (µg/m3)

>4 Increase 39 1 0

>2 to 4 Increase 58 0 1

>0.4 to 2 Increase 540 104 56

0 to 0.4 Increase 921 1,515 1,558

No Change 36 0 0

0 to 0.4 Decrease 2,035 4,542 4,629

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Change in annual mean NO2 PM10 PM2.5 (µg/m3)

>0.4 to 2 Decrease 2,467 128 48

>2 to 4 Decrease 160 2 0

>4 Decrease 36 0 0 Significance 4.5.24. The significance of local air quality changes as a result of the Proposed Scheme has been assessed with reference to LA 105 (Ref 4.1) and IAQM guidance (Ref 4.10). LA 105 4.5.25. As demonstrated in Table 4-20, there are 3 receptors included in the local air quality assessment

that fall within the criteria in Table to be considered within the significance assessment for NO2. All of these receptors represent an improvement in local air quality.

Table 4-20: Local Air Quality Assessment for Respective Receptors in the Opening Year (2021)

Magnitude of Total Number of Receptors with: Change in Annual 3 Mean NO2 (µg/m ) Worsening of air quality objective Improvement of an air quality already above objective or creation of objective already above objective or a new exceedance the removal of an existing exceedance

Large (>4) 0 1

Medium (>2-4) 0 2

Small (>0.4-2) 0 0 4.5.26. The effect of the Proposed Scheme in the opening year (2021) would be a minor improvement, in the context of the significance criteria detailed with LA 105. This includes one receptor (R2956 on

the A428 in Lower Harlestone) which is subject to a large beneficial impact in annual mean NO2 concentration (9.5 µg/m3) which removes an exceedance in the Do-Minimum scenario (Table 4.5). 4.5.27. All modelled receptors are predicted to experience annual mean concentrations below the

respective objectives for both PM10 and PM2.5 in both the 2021 Do-Minimum and Do-Something scenarios. IAQM 4.5.28. The impact descriptors provided by the IAQM guidance (Table 4-6) have been adopted to describe the potential impact of the Proposed Scheme on local air quality at each of the identified relevant receptors. The impact at the receptors is described in Table 4-21 for the opening year (2021).

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Table 4-21: Predicted Local Air Quality Impacts for Opening Year (2021)

Impact Descriptor (IAQM) Number of Receptors

NO2 PM10 PM2.5

Substantial improvement 4 0 0

Moderate improvement 63 0 0

Slight improvement 304 0 0

Negligible 5,831 6,291 6,291

Slight deterioration 55 1 1

Moderate deterioration 30 0 0

Substantial deterioration 1 0 0

4.5.29. The local NO2, PM10 and PM2.5 air quality impacts associated with the operation of the Proposed Scheme are expected to be negligible at the vast majority of the assessment receptors. More

receptors are predicted to experience an improvement in air quality with respect to NO2. One

receptor is expected to experience a slight deterioration with respect to PM10 and PM2.5. This is Receptor R5403 on Boughton Crossing, although the concentration experienced in the 3 3 Do-Something scenario is 21.1 µg/m and 13.0 µg/m for PM10 and PM2.5 respectively, which is well below their respective air quality objectives.

4.5.30. However, Receptor R5403 on Boughton Crossing experiences a substantial deterioration for NO2 (Table 4-21). The predicted concentration of 39.6 µg/m3 in the Do-Something scenario is also the highest of all the receptors assessed. Although the results for 2021 show a significant improvement in air quality overall, this substantial deterioration will be taken into account within the mitigation measures associated with the operational phase. 4.5.31. Given the results of the local air quality assessment and evaluation within the context of the IAQM significance criteria, the effect of the Proposed Scheme in the opening year (2021) would be a minor improvement. Future Year 2031

4.5.32. A summary of the predicted annual mean NO2, PM10 and PM2.5 concentrations of the considered receptors across the study area for the future year (2031) assessment is presented in Table 4-22.

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Table 4-22: Summary of Predicted Annual Mean NO2, PM10 and PM2.5 Concentrations at Sensitive Locations in Base (2018) and Future Year (2031)

Parameter NO2 PM10 PM2.5

Annual Mean 40µg/m3 40µg/m3 25µg/m3 Objective

Number of Base Exceedance 36 0 0 exceedances of (2018) respective objective by scenario Do Minimum 0 0 0 Exceedance (2021)

Do Something 0 0 0 Exceedance (2021)

Removed 0 0 0 Exceedances

New Exceedances 0 0 0

Total number of Improvement in 5,273 5,242 5,243 Properties Concentration

No Change in 23 0 0 Concentration

Deterioration in 996 1,050 1,049 Concentration

Do Something-Do Maximum -5.5 -2.3 -1.3 Minimum Annual Improvement Mean Change (µg/m3) Maximum +9.9 +4.6 +2.6 Deterioration

Total Receptors 6,425 6,425 6,425

Ratio (Improvement to Deterioration) 5.3 5.0 5.0

Annual Mean NO2 Concentrations 4.5.33. Of the 6,425 modelled receptor locations, there are predicted to be exceedances of the annual

mean NO2 objective in the base scenario. There are predicted to be 36 exceedances in the base

year and none in the Do Minimum or Do-Something scenario (Figure 4.8: Annual Mean NO2 Base

(Volume IV of the ESA), Figure 4.20: Annual Mean NO2 DM31 (Volume IV of the ESA) and

Figure 4.23: Annual Mean NO2 DS31 (Volume IV of the ESA)). The highest concentrations in 2031 are predicted at Receptor R1316, where a concentration of 27.6 µg/m3 is predicted in the Do Minimum scenario. 4.5.34. In the Do Minimum and Do Something scenarios, the annual mean concentrations at receptors located within the AQMA’s outlined in Section 4.3 are all less than or equal to 30µg/m3, meaning

they are below the annual mean objective. The majority of improvements in annual NO2 mean concentrations are predicted to occur within and adjacent to these AQMA’s.

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4.5.35. The maximum improvement is predicted at Receptor R2956 (5.5 µg/m3) on the A428 in Lower Harlestone. This is due to a reduction in traffic flows along this route in the Do Something scenario.

4.5.36. Conversely, the locations predicted to experience a worsening in annual mean NO2 concentrations are adjacent to new road links and in close proximity to the Proposed Scheme, as shown in Figure

4.26: Change in Annual Mean NO2 31 (Volume IV of the ESA). The greatest worsening is predicted at Receptor R5403 (9.9 µg/m3) on Boughton Crossing which is on the north-east boundary of the Proposed Scheme, adjacent to A5199 Welford Road. This is due to an increase in traffic flows along this route as a result of the Proposed Scheme.

4.5.37. Overall, the Proposed Scheme is predicted to cause improvements in annual mean NO2 at 5,273 properties, deteriorations at 996 properties and no change at 23 properties. The ratio of improvements to deteriorations is therefore over 5.

Hourly Mean NO2 Concentrations

3 4.5.38. The annual mean NO2 concentrations predicted by the model were all below 60 µg/m and,

therefore, hourly mean NO2 concentrations are unlikely to cause a breach of the hourly mean objective. This is in line with the guidance provided within LAQM.TG16 (Ref 4.2), which states ‘Previous research carried out on behalf of Defra and the Devolved Administrations identified that

exceedances of the NO2 1-hour mean are unlikely to occur where the annual mean is below 60 µg/m3’.

Annual Mean PM10 Concentrations

4.5.39. There are predicted to be no exceedances of the annual mean PM10 in either the base, Do Minimum

or Do Something scenario (Figure 4.9: Annual Mean PM10 Base (Volume IV of the ESA), Figure

4.21: Annual Mean PM10 DM31 (Volume IV of the ESA) and Figure 4.24: Annual Mean PM10 DS31 (Volume IV of the ESA)). The highest concentrations in 2031 are predicted at Receptor R643, where a concentration of 21.6 µg/m3 is predicted in the Do Something scenario. This receptor is located on the A508 to the north of Northampton AQMA No 6.

4.5.40. The majority of improvements in annual NO2 mean concentrations are predicted to occur at properties within or adjacent to the three AQMA’s highlighted in Section 4.3. The maximum improvement is predicted at Receptor R2956 (2.3 µg/m3) on the A428 in Lower Harlestone. This is due to a reduction in traffic flows along this route in the Do Something scenario.

4.5.41. Conversely, the locations predicted to experience a worsening in annual mean NO2 concentrations are located adjacent to new road links and in close proximity to the Proposed Scheme, as shown in

Figure 4.27: Change in Annual Mean PM10 31 (Volume IV of the ESA). The greatest worsening is predicted at Receptor R5403 (4.6 µg/m3) on Boughton Crossing which is on the north-east boundary of the Proposed Scheme, adjacent to A5199 Welford Road.

4.5.42. Overall, the Proposed Scheme is predicted to cause improvements in annual mean PM10 at 5,242 properties and deteriorations at 1,050 properties.

Daily Mean PM10 Concentrations

4.5.43. Exceedances of the 24-hour mean objective for PM10 are unlikely if the annual mean concentration 3 is below 32 µg/m . Given that no modelled PM10 values are above this level, exceedances of the 24-hour objectives are very unlikely.

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Annual Mean PM2.5 Concentrations

4.5.44. There are predicted to be no exceedances of the annual mean PM2.5 in either the base, Do Minimum

or Do Something scenario (Figure 4.10: Annual Mean PM2.5 Base (Volume IV of the ESA), Figure

4.22: Annual Mean PM2.5 DM31 (Volume IV of the ESA) and Figure 4.25: Annual Mean PM2.5 DS31 (Volume IV of the ESA)). The highest concentrations in 2031 are predicted at Receptor R5403, where a concentration of 13.2 µg/m3 is predicted in the Do Something scenario.

4.5.45. The majority of improvements in annual NO2 mean concentrations are predicted to occur at properties within or adjacent to the three AQMA’s highlighted in Section 4.3. The maximum improvement is predicted at Receptor R2956 (1.3 µg/m3) on the A428 in Lower Harlestone. This is due to a reduction in traffic flows along this route in the Do Something scenario.

4.5.46. Conversely, the locations predicted to experience a deterioration in annual mean NO2 concentrations are located adjacent to new road links and in close proximity to the Proposed

Scheme, as shown in Figure 4.28: Change in Annual Mean PM2.5 31 (Volume IV of the ESA). The greatest worsening is predicted at Receptor R5403 (2.6 µg/m3) on Boughton Crossing which is on the north-east boundary of the Proposed Scheme, adjacent to A5199 Welford Road. Overall, the

Proposed Scheme is predicted to cause improvements in annual mean PM10 at 5,242 properties and deteriorations at 1,050 properties. Magnitude of Change

4.5.47. The predicted magnitude of change in annual mean NO2, PM10 and PM2.5 concentrations across all modelled relevant receptors are summarised in Table 4-23. These have been calculated with reference to the magnitude of change criteria provided in LA 105.

4.5.48. For annual mean NO2, the vast majority of receptors sit in the magnitude of an imperceptible to 3 small decrease (0 - 2 µg/m ). For both PM10 and PM2.5, the vast majority of receptors sit in the magnitude of change range 0 - 0.4 µg/m3 which are classed as imperceptible to small decrease.

Table 4-23: Predicted Magnitude of Change in Annual Mean Concentrations in the Future Year (2031)

3 Change in annual mean (µg/m ) NO2 PM10 PM2.5

>4 Increase 3 1 0

>2 to 4 Increase 33 1 1

>0.4 to 2 Increase 355 128 40

0 to 0.4 Increase 605 920 1,008

No Change 23 0 0

0 to 0.4 Decrease 2,570 4,540 5,153

>0.4 to 2 Decrease 2,585 696 90

>2 to 4 Decrease 108 6 0

>4 Decrease 10 0 0

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Significance 4.5.49. The significance of local air quality changes as a result of the Proposed Scheme has been assessed with reference to LA 105 (Ref 4.1) and IAQM guidance (Ref 4.10). LA 105 4.5.50. As demonstrated in Table 4-24, there are no receptors included in the local air quality assessment

that falls within the criteria in Table 4-5 to be considered within the significance assessment for NO2. All modelled receptors are predicted to experience annual mean concentrations below the

respective objectives for both PM10 and PM2.5 in both the 2031 Do Minimum and Do Something scenarios.

Table 4-24: Local Air Quality Assessment for Respective Receptors in the Future Year (2031)

Total Number of Receptors with: Magnitude of Change in Annual Worsening of air quality objective Improvement of an air quality Mean NO (µg/m3) 2 already above objective or creation of objective already above objective or a new exceedance the removal of an existing exceedance

Large (>4) 0 0

Medium (>2-4) 0 0

Small (>0.4-2) 0 0 4.5.51. Given the results of the local air quality assessment and evaluation within the context of the significance criteria, the operation of the Proposed Scheme would constitute a negligible environmental effect with respect to local air quality in 2031. IAQM 4.5.52. The impact descriptors provided by the IAQM guidance (Table 4-6) have been adopted to describe the potential impact of the Proposed Scheme on local air quality at each of the identified relevant receptors. The impact at the assessment receptors is described in Table 4-25 for the future year (2031).

Table 4-25: Predicted Local Air Quality Impacts for the Future Year (2031)

Impact Descriptor (IAQM) Number of Receptors

NO2 PM10 PM2.5

Substantial improvement 0 0 0

Moderate improvement 9 0 0

Slight improvement 55 1 0

Negligible 6,199 6,289 6,291

Slight worsening 26 1 1

Moderate worsening 3 1 0

Substantial worsening 0 0 0

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4.5.53. The local air quality impacts associated with the operation of the Proposed Scheme are expected to negligible at the majority of the assessment receptors, with more receptors predicted to experience a slight improvement in air quality as opposed to a deterioration. There are no receptors predicted to experience a substantial worsening of local air quality, furthermore, the maximum concentration in the Do-Something scenario, at Receptor R5403, is 26.5 µg/m3. 4.5.54. Given the results of the local air quality assessment and evaluation within the context of the IAQM significance criteria, the effect of the Proposed Scheme in the future year (2031) would be negligible with respect to local air quality and no specific mitigation is proposed. Supplementary Analysis Sensitivity testing of bias adjustment factors 4.5.55. As outlined in Section 4.2, NBC have applied a mixture of local and national bias adjustment factors to raw monitoring data over the last five reporting years. 4.5.56. A summary of the factors applied is shown in Table 4-26.

Table 4-26: Details of Bias Adjustment Factors Used in Previous Reporting Years for NBC LAQM

ASR Data Bias Local/National Data source Reporting period adjustment Bias Adjustment Period factor used Factor

2012 2011 0.71 Local (Roadside) AURN roadside ( Road)

2014 2013 0.73 Local (Roadside) AURN roadside (Wellingborough Road)

2017 2016 0.85 Local (Roadside) AURN roadside (Wellingborough Road)

2018 2017 0.89 National National factor from Defra

2019 2018 0.79 Local AURN urban background (Spring Park) (Background)

4.5.57. NBC therefore requested sensitivity testing to be undertaken using monitoring data adjusted using both local and national bias adjustment factors during the verification process. To complete the

sensitivity testing for this assessment, results for the top ten highest NO2 receptor concentrations in the Do-Something 2021 scenario were analysed as follows:  2018 monitoring data was bias corrected using a Local (Background) factor, the highest historical Local (Roadside) factor (0.85) and the national bias adjustment factor from Defra;

 Adjustment factors were determined as the factors required to uplift the modelled road-NOx predicted concentrations for 2018 to the three bias corrected monitoring datasets;

 Adjusted modelled road-NOx concentrations (2021) were combined with the Defra background mapped datasets (2021) for each bias corrected dataset; and

 Adjusted modelled road-NOx concentrations (2021) were combined with the urban background monitored concentration from Spring Park (12.9 µg/m3 in 2018) for each bias corrected dataset.

4.5.58. The bias adjustment factors applied are shown in Table 4-27.

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Table 4-27: Details of Bias Adjustment Factors Used in the Supplementary Analysis

ASR Data Bias Local/National Data source Reporting period adjustment Bias Adjustment Period factor used Factor

2019 2018 0.93 National National factor from Defra

2017 2016 0.85 Local (Roadside) AURN roadside (Wellingborough Road)

2019 2018 0.79 Local AURN urban background (Spring Park) (Background)

4.5.59. This process is outlined in Appendix 4.4: Dispersion Model Approach and Verification (Volume III of the ESA). 4.5.60. Results of the sensitivity testing are shown in Table 4-28.

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Table 4-28: Sensitivity Testing – Do-Something 2021 NO2

3 ID Site Location In Predicted NO2 Concentration – Do-Something 2021 (µg/m ) AQMA?

Local bias Local bias Local bias Local bias National bias National bias adjustment adjustment adjustment adjustment adjustment adjustment factor 0.79 – factor 0.79 – factor 0.85 – factor 0.85 – factor 0.93 – factor 0.93 – Defra Monitored Defra Monitored Defra Monitored Backgrounds Background Backgrounds Background Backgrounds Background

R5403 Boughton Crossing No 39.6 44.1 43.3 47.7 48.3 52.5

R4764 A508 Kingsthorpe Yes 39.1 41.0 42.4 44.3 46.9 48.7

R1316 A5095 Washington Street Yes 38.8 40.2 42.0 43.4 46.4 47.8

R2615 A508 Kingsthorpe Yes 38.4 40.3 41.6 43.5 46.0 47.8

R3962 A508 St George’s Street No 37.1 37.1 40.0 40.0 43.9 43.9

R2964 A508 Campbell Street Yes 37.1 37.1 40.0 40.0 43.9 43.9

R643 A428 Grafton Street Yes 37.1 37.1 40.0 40.0 43.9 43.9

R1281 A428 Grafton Street Yes 37.1 37.1 40.0 40.0 43.9 43.9

R2700 A508 St George’s Street No 37.1 37.1 40.0 40.0 43.9 43.9

R3584 A428 Grafton Street Yes 37.1 37.1 40.0 40.0 43.9 43.9

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4.5.61. Table 4-28 shows the top ten highest results calculated using the local bias adjustment factor (0.79)

will not exceed the annual mean NO2 objective when combined with the Defra background for 2021. For all bias correction methods, the 5th to 10th highest concentrations are all predicted to be within 0.1 µg/m3) because they are in the same background square inside AQMA No.6 and are all subject to the same, dominant source of emission which is A508 Barrack Road in central Northampton (Figure 4.1). 4.5.62. When combined with the fixed background from Spring Hill (2018) (Table 4-28) exceedances are predicted at the four highest receptors Boughton Crossing, on A508 Kingsthorpe and A5095 Washington Street in 2021. It should be noted that the application of a fixed background from 2018 to 2021 is potentially conservative because anticipated reductions in pollution from the increased penetration of cleaner vehicles into the fleet and council air quality action plan measures are not represented. Furthermore, the use of a fixed background across the model domain does not allow for variability in background which could be another source of over-estimation in specific locations. 4.5.63. The predicted concentrations using the historical local (roadside) (0.85) and national bias adjustment factor (0.93) in Table 4-28 are higher than the concentrations calculated using the local (background) bias factor (0.79). Exceedances are predicted at the top ten receptors using these factors with the Defra mapped background and monitored background from Spring Hill. These predicted concentrations are likely to be unrealistic because these bias adjustment factors are considered to be too high for the following reasons:  The historical local (roadside) factor (0.85) is the highest derived from historical local (roadside) site which indicates that 2016 was an anomalous year;  The historical local (roadside) factors for 2012 (0.71) and 2014 (0.73) are lower than the local (background) factor of 0.79;  The local (background) bias adjustment factor determined from the 2019 data at Spring Hill is 0.77 which also lies within the historical bias adjustment factor range for the study area of 0.71 to 0.79 (with the exception of data year 2016). 4.5.64. Results calculated using the local bias adjustment factor (0.79) are therefore likely to be the most accurate and therefore are the basis for the judgement of impact magnitude and significance for the scheme. Air Quality Focus Areas Daventry District Council 4.5.65. Boughton Crossing is included within the study area as it meets the required criteria outlined in LA 105 (Section 4.1.9) (Ref 4.1) for inclusion. The traffic data showed an increase in Annual Average Daily Traffic of 6,631 in the Do-Something scenario in 2021 when compared to the Do- Minimum scenario. This is due to its location in close proximity to the north-eastern site boundary and the A5199 entry point of the Proposed Scheme. 4.5.66. Receptor R5403 lies on Boughton Crossing and experiences an increase in pollutant concentration

in the Do-Something scenario for all pollutants. The NO2 concentration experienced in the Do- Something scenario in 2021, 39.6 µg/m3, lead to a ‘substantial deterioration’ classification in accordance with IAQM criteria. Therefore, it is recommended that the Health Distributional Impacts are assessed to inform damage cost as part of the Proposed Scheme appraisal (Section 4.5.68).

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Northampton Borough Council - White Elephant Junction (Race Course/ Kettering Road), The Drapery and North Gate Bus Station area and Abington Square Area 4.5.67. The modelled traffic data at these locations show the following reductions in AADT in the Do- Something scenario in 2021 when compared to the Do-Minimum scenario:  White Elephant Junction (Race Course/ Kettering Road) – reduction of 182 AADT  The Drapery and North Gate Bus Station area – reduction of 598 AADT  Abington Square Area – reduction of 198 AADT 4.5.68. Changes in total flow are all below 1,000 AADT, changes in HDV flows are below 200, there is no change in speed band and the carriageway alignment will not change as a result of the relief road. Therefore, these locations were not included in the study area as predicted changes in traffic flows did not meet the required criteria outlined in LA 105 (Section 4.1.9) (Ref 4.1) for inclusion. Indeed, these focus areas show that the relief road is predicted to remove traffic from the centre of Northampton in opening year 2021. The relief road will therefore likely to lead to beneficial impacts on air quality although any changes in monitored pollutant concentrations will be largely imperceptible as a result. Overall Significance 4.5.69. The overall significance for the scheme is judged as not significant for the following reasons:  All base year exceedances are removed;  Results for 2021 and 2031 show that no exceedances of the objectives are predicted;  More beneficial impacts than adverse impacts are predicted by a ratio of 3:1 in 2021 and 5.3:1 in 2031;  Moderate and substantial beneficial impacts are predicted to outweigh moderate and substantial adverse impacts in 2021 and 2031;  Model performance as measured by the Root Mean Square Error (RMSE) metric (Appendix 4.4) is considered to be acceptable for such a large, diverse study area; and  In the Do-Minimum (2021) scenario, there are more predicted receptor concentrations within +4.4 µg/m3 of the objective than the Do-Something (2021) scenario. 4.5.70. Although the proposed scheme is judged as not significant, model performance must be considered where concentrations are predicted to be close to the objective. In the Do-Minimum (2021) scenario, 3 annual average NO2 is predicted to be within 4.4 µg/m of the objective at 57 properties. In the Do-Something (2021) scenario 28 are predicted. Therefore, the number of properties where exceedances could occur but are not predicted as a result of poor model performance, is predicted to reduce as a result of the scheme. 4.5.71. As a conservative approach it is considered necessary to mitigate properties where impacts are predicted to be substantial adverse. It should be noted that this is a conservative approach because the predicted concentration could optimistically be up to 4.4 µg/m3 lower.

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MITIGATION MEASURES 4.5.72. Although the Proposed Scheme is not considered to have a significant environmental effect, there is one receptor, R5403 at Boughton Crossing, which experiences a substantial worsening of air quality in the Do-Something 2021 scenario as a result of the Proposed Scheme. This receptor is within 20 m of the Proposed Scheme boundary and experiences the maximum worsening in both the 2021 and 2031 assessment scenarios. 4.5.73. As such, it is recommended that the Health Distributional Impacts are assessed to inform damage cost as part of the Proposed Scheme appraisal. SUMMARY OF LIKELY RESIDUAL SIGNIFICANT EFFECTS Temporary Construction 4.5.74. With a negligible impact of magnitude predicted at receptors after the implementation of mitigation measures, residual effects would be negligible. Operational Phase 4.5.75. With a negligible impact of magnitude predicted at receptors after the implementation of mitigation measures, residual effects would be negligible. CUMULATIVE EFFECTS Cumulative Effects 4.5.76. No intra cumulative effects are anticipated that involve air quality. In-Combination Effects 4.5.77. Committed developments that are expected to influence local traffic flows have been accounted for within the traffic data provided for the air quality assessment. Given the Proposed Scheme is not considered to have a significant environmental effect, no cumulative operational phase impacts are anticipated. PCM LINKS 4.5.78. Increases at all modelled receptors adjacent to PCM links (Tables 4-9 and 4-12) are predicted to be small enough so as not to cause exceedances when added to the PCM concentration (Figure 4.7:

PCM Network (Volume IV of the ESA) and Figure 4.14: Annual Mean NO2 DS21 (Volume IV of the ESA)). 4.5.79. Therefore, in accordance with LA 105, a compliance risk assessment is not required. ECOLOGICAL ASSESSMENT 4.5.80. An assessment of changes in air quality at the identified designated sites has been undertaken with reference to LA 105 (Ref 4.1). The detailed results for modelled transects representing each individual ecological site are given in Appendix 4.5: Ecological Assessment Results and Impacts (Volume III of the ESA). Opening Year 2021

4.5.81. The maximum modelled annual mean NOx concentrations, nitrogen deposition rates and acid deposition rates for the opening year (2021) are presented in Table 4-27, Table 4-28 and Table 4- 29, respectively, for each designated site.

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Table 4-27: Total Annual Mean NOx Concentrations (2021)

3 ID and Transect Location Distance to Road Total NOx Concentration (µg/m )

Do Minimum Do Something Change

Upper Nene Valley Gravel 125 m 29.7 29.6 -0.14 Pits – ER1

Barnes Meadow – ER41 0 m 108.6 107.3 -1.30

Berry Wood – ER62 145 m 14.5 14.6 +0.05

Kingsthorpe – ER95 0 m 66.5 52.1 -14.36

Annual Mean Objective 30

Table 4-28: Total Nitrogen Deposition Rates (2021)

ID and Transect Location Distance to Road (A45) Total N Deposition (kg N/ha/yr) (2021)

Do Minimum Do Something Change

Upper Nene Valley Gravel 125 m 20.8 20.8 -0.01 Pits2 – ER1

Barnes Meadow2 – ER41 0 m 25.7 25.7 -0.07

Berry Wood1 – ER62 145 m 30.3 30.3 +0.01

Kingsthorpe2 – ER95 0 m 21.2 20.3 -0.92

Critical Load Range* 110 - 20 kg N/ha/yr, 220-30 kg N/ha/yr

Table 4-29: Total Acid Deposition Rates (2021)

ID and Transect Location Distance to Road (A45) Total Acid Deposition (keq N/ha/yr) (2021)

Do Minimum Do Something Change

Upper Nene Valley Gravel 125 m 1.51 1.51 0.00 Pits1 – ER1

Barnes Meadow1 – ER41 0 m 1.84 1.83 -0.01

Berry Wood2 – ER62 145 m 2.13 2.13 0.00

Kingsthorpe1 – ER95 0 m 1.51 1.45 -0.07

Critical Load Range* 10.223 – 0.673 keq N/ha/yr, 20.142 – 1.076 keq N/ha/yr

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4.5.82. The results in Table 4-27 indicate that there will be an exceedance of the annual mean NOx objective at the Barnes Meadow and Kingsthorpe LNR, which is predicted in both base (2018) and assessment (2021) Do Minimum and Do Something scenarios. In the Do Minimum and Do Something scenarios for Barnes Meadow, exceedances are predicted to occur at the closest nine transect points to the road (ER41 - ER49). For Kingsthorpe, exceedances are predicted at the closest transect point to the road only (ER95). Beyond these distances, all predicted annual mean NOx concentrations are below the respective objective in the Do Minimum and Do Something scenarios. For both the closest transect point is placed at the absolute worst-case roadside location, in addition, both experience a reduction in concentration in the Do-Something scenario. The values for Barnes Meadow are particularly high due to the adjacent A45 which experiences heavy traffic.

4.5.83. The maximum predicted decrease in NOx between the Do Minimum and Do Something scenario is - 14.36 µg/m3 at Kingsthorpe LNR. There is a small increase predicted at Berry Wood Ancient Woodland, however this is considered to be imperceptible with reference to LA 105, which states that a significant effect is not likely where the change in concentration is less than 0.4 µg/m3. 4.5.84. The predicted rates of nitrogen deposition with and without the Proposed Scheme in the Assessment Year (2021) were compared to the respective critical loads (CL) for the habitats within each of the ecological sites to determine the potential for significant effects. As detailed in Table 4- 28, the nitrogen deposition rate predicted at the nearest transect point relative to the road is above the respective critical load ranges, as detailed within Table 4-10, for Berry Wood. 4.5.85. The critical load ranges for nitrogen deposition are predicted to be exceeded at all transect points assessed in the Do Minimum and both Do Something scenarios for Berry Wood. However, this is attributed to the existing high N-deposition rates (see Table 4-10), which when interpolated to 2021 continue to exceed the relevant critical load values without the addition of the Proposed Scheme. Three of the four designated sites experience a decrease in nitrogen deposition rates in the Do-Something scenario. There is a small increase at Berry Wood Ancient Woodland, however this is classified as insignificant with respect to LA 105. 4.5.86. The critical load ranges for acid deposition are predicted to be exceeded at all transect points assessed in the Do Minimum and both Do Something scenarios for the four designated sites. The critical loads used to assess each designated site, as seen in Table 4-29, are the minimum critical loads (Table 4-10), chosen to represent a worst-case assessment of the ecological conditions. There is a slight decrease in acid deposition rates in the Barnes Meadow and Kingsthorpe designated sites in the Do-Something scenario, with no change predicted for at the other designations. 4.5.87. Therefore, in the opening year (2021), the ecological impact is expected to be negligible. Further detail for the ecological designations is provided in Appendix 4.5: Ecological Assessment Results and Impacts (Volume III of the ESA). Future Year 2031

4.5.88. The maximum modelled annual mean NOx concentrations, nitrogen deposition rates and acid deposition rates for the future year (2031) are presented in Table 4-30, Table 4-31 and Table 4-32, respectively, for each designated site.

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Table 4-30: Total Annual Mean NOx Concentrations (2031)

3 ID and Transect Location Distance to Road Total NOx Concentration (µg/m )

Do Minimum Do Something Change

Upper Nene Valley Gravel 125 m 19.8 19.7 -0.11 Pits – ER1

Barnes Meadow – ER41 0 m 47.6 46.8 -0.81

Berry Wood – ER62 145 m 11.14 11.1 -0.07

Kingsthorpe – ER95 0 m 42.0 33.8 -8.17

Annual Mean Objective 30

Table 4-31: Total Nitrogen Deposition Rates (2031)

ID and Transect Location Distance to Road (A45) Total N Deposition (kg N/ha/yr) (2021)

Do Minimum Do Something Change

Upper Nene Valley Gravel 125 m 20.4 20.4 -0.01 Pits2 – ER1

Barnes Meadow2 – ER41 0 m 23.1 23.1 -0.05

Berry Wood1 – ER62 145 m 30.2 30.2 -0.01

Kingsthorpe2 – ER95 0 m 19.8 19.2 -0.55

Critical Load Range* 110 - 20 kg N/ha/yr, 220-30 kg N/ha/yr

Table 4-32: Total Acid Deposition Rates (2031)

ID and Transect Location Distance to Road (A45) Total Acid Deposition (keq N/ha/yr) (2021)

Do Minimum Do Something Change

Upper Nene Valley Gravel 125 m 1.47 1.47 0.00 Pits1 – ER1

Barnes Meadow1 – ER41 0 m 1.65 1.65 0.00

Berry Wood2 – ER62 145 m 2.12 2.12 0.00

Kingsthorpe1 – ER95 0 m 1.41 1.37 -0.04

Critical Load Range* 10.223 – 0.673 keq N/ha/yr, 20.142 – 1.076 keq N/ha/yr

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4.5.89. The results in Table 4-30 indicate that there will be an exceedance of the annual mean NOx objective at the Barnes Meadow and Kingsthorpe LNR, which is predicted in both Do Minimum and Do Something scenarios. In the Do Minimum and Do Something scenarios for Barnes Meadow, exceedances are predicted to occur at the closest transect points to the road only (ER41). For Kingsthorpe, exceedances are also predicted at the closest transect point to the road only (ER95). Beyond these distances, all predicted annual mean NOx concentrations are below the respective objective in the Do Minimum and Do Something scenarios. For both the closest transect point is placed at the absolute worst-case roadside location, in addition, both experience a reduction in

concentration in the Do-Something scenario. The maximum predicted decrease in NOx between the Do Minimum and Do Something scenario is 8.17 µg/m3, there are no predicted increases attributed to the Proposed Scheme 4.5.90. The predicted rates of nitrogen deposition with and without the Proposed Scheme in the Future Year (2031) were compared to the respective critical loads (CL) for the habitats within each of the ecological sites to determine the potential for significant effects. As detailed in Table 4-31, the nitrogen deposition rate predicted at the nearest transect point relative to the road is above the respective critical load ranges, as detailed within Table 4-10, for Berry Wood. 4.5.91. The critical load ranges for nitrogen deposition are predicted to be exceeded at all transect points assessed in the Do Minimum and both Do Something scenarios for Berry Wood. However, this is attributed to the existing high N-deposition rates (see Table 4-10), which when interpolated to 2031 continue to exceed the relevant critical load values without the addition of the Proposed Scheme. The four designated sites experience a decrease in nitrogen deposition rates in the Do-Something scenario. 4.5.92. The critical load ranges for acid deposition are predicted to be exceeded at all transect points assessed in the Do Minimum and both Do Something scenarios for the four designated sites. The critical loads used to assess each designated site, as seen in Table 4-32, are the minimum critical loads (Table 4-10), chosen to represent a worst-case assessment of the ecological conditions. There is a slight decrease in acid deposition rates in the Kingsthorpe LNR in the Do-Something scenario, with no change predicted for at the other designations. 4.5.93. Therefore, in the future year (2031), the ecological impact is expected to be negligible. Further detail for the ecological designations is provided in Appendix 4.5: Ecological Assessment Results and Impacts (Volume III of the ESA). MONITORING 4.5.94. On the basis of there being no significant effects, there are no specific requirements for monitoring air quality effects from the Proposed Scheme.

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4.6 REFERENCES  Ref. 4.1: Design Manual for Roads and Bridges (DMRB) LA 105 Air Quality, November 2019  Ref. 4.2: Department for Environment, Food and Rural Affairs (2018) Part IV: The Environment Act 1995 and Environment (Northern Ireland) Order 2002 Part III, Local Air Quality Management Technical Guidance LAQM.TG16.  Ref. 4.3: Institute of Air Quality Management (Version 1.1 Updated June 2016). Guidance on the Assessment of Dust from Demolition and Construction.  Ref. 4.4: Department for Environment, Food and Rural Affairs (2007). The Air Quality Strategy for England, Scotland, Wales and Northern Ireland Volumes 1 and 2. Defra: London.  Ref. 4.5: Department for Environment, Food and Rural Affairs (2007). The Air Quality Strategy for England, Scotland, Wales and Northern Ireland Volumes 1 and 2. Defra: London.  Ref. 4.6: Department for Environment, Food and Rural Affairs (2019) Clean Air Strategy 2019 [online] https://www.gov.uk/government/publications/clean-air-strategy-2019  Ref. 4.7: The Environmental Protection Act 1990. Chapter 43  Ref. 4.8: Ministry of Housing, Communities and Local Government (2019) National Planning Policy Framework [online] https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/fil e/779764/NPPF_Feb_2019_web.pdf  Ref. 4.9: West Northamptonshire Joint Core Strategy Local Plan (Part 1) – West Northamptonshire Joint Planning Unit (December 2014)  Ref. 4.10: Environmental Protection UK and Institute of Air Quality Management (Version 1.2 Updated January 2017). Land Use Planning & Development Control: Planning for Air Quality.  Ref. 4.11: Air Quality Annual Status Report – Northampton Borough Council (June 2019)  Ref. 4.12: Air Quality Annual Status Report – Daventry District Council (February 2018)  Ref. 4.13: https://uk-air.defra.gov.uk/aqma/maps (Accessed 10/05/2020)  Ref. 4.14: Department for Environment, Food and Rural Affairs (2018) Background Mapping data for local authorities – 2017 [online] https://uk-air.defra.gov.uk/data/laqm-background- maps?year=2017 (Accessed 10/05/2020)  Ref. 4.15: https://magic.defra.gov.uk/ (Accessed 10/05/2020)  Ref. 4.16: http://www.apis.ac.uk/ (Accessed 15/05/2020)

 Ref. 4.17: NO2 Concentrations and Distance from Roads – Air Quality Consultants July 2008  Ref. 4.18: AQTAG06 Technical guidance on detailed modelling approach for an appropriate assessment for emissions to air – March 2014  Ref. 4.19: Letter: From Jamie Bond, Environmental Public Health Scientist to Peter Moor, Principal Development Control Officer (1 August 2019). Subject: RE: Planning application for The Construction of the proposed Northampton North West Relief Road; Land off the A5199 Northampton Road, Northampton. Application Number: Ref 19/00045/CCDFUL  Ref. 4.20: Northampton Borough Council 2019 Diffusion Tube Bias Adjustment. Local Air Quality Management 2019 – Bureau Veritas (December 2019)

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5 CLIMATE CHANGE

5.1 INTRODUCTION 5.1.1. This chapter reports the outcome of the assessment of effects arising from the construction and operation of the Proposed Scheme upon Greenhouse Gas (GHG) emissions. 5.1.2. This chapter supersedes the Greenhouse Gas assessment within Chapter 8: Climate Change (Volume II of the 2019 ES). Note, there is no Addendum to the Climate Resilience assessment reported in the 2019 ES (refer to Section 5.2 for further details). 5.1.3. This Chapter describes the assessment methodology, baseline conditions, any mitigation measures adopted for the purposes of the assessment, a summary of effects, further mitigation measures required to prevent, reduce or offset any negative effects, and the likely residual effects after these measures have been employed. 5.2 SCOPE, ASSUMPTIONS, AND LIMITATIONS CONSULTATION 5.2.1. No consultation with external (statutory) consultees is required or has been undertaken for the assessment of GHG emissions for the ESA as no responses to the EIA Scoping Addendum Report (Appendix 3.6 (Volume III of the ESA)) were received. SCOPE OF THE ASSESSMENT 5.2.2. This section provides an update to the scope of the assessment and states the evidence base for scoping in and scoping out elements. There have been no updates to the construction data since the 2019 ES, as such the construction phase will not be considered as part of this ES Addendum, only the operational phase will be assessed. Elements scoped out of the assessment 5.2.3. The GHG Scoping process follows the principles of PAS 2080:2015 Carbon Management in Infrastructure (Ref. 5-1) which provides a breakdown of stages A1-C-43 of whole life carbon assessments. The elements shown in Table 5-1 are not predicted to change significantly from the assessments presented in the 2019 ES and have therefore not been subject to further assessment:

3 The alphanumeric code is a PAS2080 lifecycle reference, which ensures the emissions categories are accurately communicated.

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Table 5-1: Elements scoped out of the assessment

Element scoped out Justification

Maintenance, repair, replacement and As there has been no change to the design of the refurbishment emissions (B2, B3, B5) Proposed Scheme since the 2019 ES, emissions for maintenance, repair, replacement and refurbishment have not been scoped into the ESA.

Operational energy consumption (B1) There has been no change to the lighting design since the 2019 ES and therefore it is predicted that there will be no change to the assumed magnitude of emissions for the ES Addendum. As such, operational energy consumption (lighting) has been scoped out of this assessment.

Elements scoped into the assessment 5.2.4. The following elements (Table 5-3) are considered to have the potential to lead to a change in the significance of effects during operation of the Proposed Scheme when compared with the Proposed Scheme as presented in the 2019 ES and have therefore been considered within the ESA. Table 5-3: Elements scoped into the operational stage

Lifecycle stage Key GHG source

5.2.5. End-user emissions5.2.6. Changes in end-user emissions are predicted due the changes in traffic flows on (regional traffic flows) the Proposed Scheme and on the surrounding network. This has the potential to B9/D increase or decrease emissions depending on the effect on flows.

LIMITATIONS AND ASSUMPTIONS 5.2.7. There is currently no specific guidance or carbon emissions threshold, which, if exceeded, is considered significant. Professional judgement and current guidance, listed in 5.3.16, have been used to undertake the assessment. 5.2.8. The assessment has been undertaken based on current available information regarding the scale and nature of the Proposed Scheme. 5.2.9. Some small emissions sources have been excluded as emissions from these sources are not considered likely to be large and therefore not material to the assessment. 5.2.10. There will be some uncertainty regarding traffic data as the model is based on traffic assumptions that project into the future.

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5.3 METHODOLOGY LEGISLATIVE FRAMEWORK 5.3.1. The applicable legislative framework is summarised as follows: United Nations Framework Convention on Climate Change 5.3.2. The UK is a member of the United Nations Framework Convention on Climate Change (UNFCCC) (Ref. 5-2), which drives international action on climate change. The UK has pledged to reduce emissions under the Paris Agreement (Ref. 5-3), as a part of a joint pledge by members of the European Union (EU). This provides an overarching commitment by the UK. Directive 2014/52/EU on Assessment of The Effects of Certain Public and Private Projects on The Environment (The EIA Directive) 5.3.3. The Environmental Impact Assessment (EIA) Directive provides the overarching legislative framework for assessing the significance of impacts and effects from schemes on the environment. The Directive requires EIA to identify, describe and assess the direct and indirect significant effects of a project on the climate (Article 3). It also stipulates that the information to be included within the EIA Report should include the ‘impact of the project on climate (for example the nature and magnitude of greenhouse gas emissions) and the vulnerability of the project to climate change’ (Ref. 5-4). UK Climate Change Act 5.3.4. The Climate Change Act 2008 (Ref. 5-5) established a legal requirement for an 80% reduction in the GHG emissions of the UK economy by 2050 in comparison to the 1990 baseline. The Act also created the Committee on Climate Change (Ref. 5-6), with a responsibility for: • Setting five-year carbon budgets (See Table 5.4) • Advising and scrutinising the UK Government’s associated climate change adaptation programmes; and • Producing a national adaptation plan for the UK Government to implement.

Infrastructure Carbon Review 5.3.5. In 2013, the UK government published the Infrastructure Carbon Review (Ref. 5-77), aiming to “release the value of lower carbon solutions and to make carbon reduction part of the DNA of infrastructure in the UK.” Major infrastructure owners, operators and developers were invited to endorse, become signatories and make commitments under the review. 5.3.6. The review provided increased emphasis on ‘capital carbon’ (GHG emissions associated with raw materials, activities and transport for construction, repairs, replacement, refurbishment and de- construction of infrastructure) while acknowledging that ‘operational carbon’ (associated with energy consumption for the operation and use of infrastructure) will continue to dominate overall emission to 2050 and beyond. 5.3.7. The Infrastructure Carbon Review highlighted the importance of assessing GHG emissions early in the lifecycle of an infrastructure scheme when there is the greatest carbon reduction potential. The Infrastructure Carbon Review also led to the publication of a Publicly Available Specification on infrastructure carbon management; PAS2080:2016. (Ref. 5-1).

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PLANNING POLICY National Planning Policy Framework 5.3.8. The National Planning Policy Framework (NPPF) (Ref. 5-8) sets out the core planning principle of supporting “the transition to a low carbon future in a changing climate…”: 5.3.9. Chapter 4: Promoting Sustainable Transport Considers how people should be offered a choice of transportation modes, encouraging a movement away from the use of single private vehicles, the latter being understood to contribute to a significant proportion of total UK carbon emissions. For example, between 1990 and 2007, domestic transport comprised 24% of total UK emissions; the largest share was from road passenger cars at 86% (Ref. 5-9). In 2013, domestic and international transport accounted for 26% of all UK greenhouse gas emissions. (Ref.5-10) National Policy Statement for National Networks 5.3.10. The project is not considered to be a Nationally Significant Infrastructure Project (NSIP), and planning consent will therefore be sought from Northampton County Council (NCC) rather than the planning inspectorate via the Development Consent Order (DCO) process. 5.3.11. This means that the National Policy Statement for National Networks (NPSNN), which “sets out the need for, and Government’s policies to deliver, development of nationally significant infrastructure projects”, is not directly relevant. However, the NPSNN does include useful context for the development of road Schemes. As such the following chapters of the NPSNN (Ref.5-11) that are relevant to GHG emissions are presented below: Chapter 3: Wider Government policy on national networks 5.3.12. Emissions: Identifies that the transport sector will play an important part in meeting the Government’s carbon targets. It is acknowledged that technologies, fuels, and promoting lower carbon transport choices will make the biggest reductions and that (comparatively) the likely impact from road development is “very small”. 5.3.13. Sustainable transport: Describes how carbon impacts can be reduced by promoting “sustainable modes of transport and high-quality cycling and walking environments” which are “essential to reducing carbon emissions from transport”. Chapter 4: Assessment principles 5.3.14. Environmental Impact Assessment: This section sets out the fact that all proposals are subject to the EIA Directive (2011/92/EU) which requires “an environmental impact assessment to identify, describe and assess effects on…air, climate…and the interactions between them”. Chapter 5: Generic impacts 5.3.15. Carbon emissions: Sets out Government policy on climate change and outlines the importance of reducing carbon emissions, stating that the Government has a legally binding commitment to reduce GHG emissions by “at least 80% by 2050” and to conform to carbon budgets outlined in the “Carbon Plan 2011” (Ref. 5-12). The policy states that “any Environmental Statement will need to describe an assessment of any likely significant climate factors in accordance with the requirements in the EIA Directive”.

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However, it goes on to say that: “It is very unlikely that the impact of a road project will, in isolation, affect the ability of Government to meet its carbon reduction plan targets. However, road projects applicants should provide evidence of the carbon impact of the project and an assessment against the Government’s carbon budgets”. The policy also states that “an increase in carbon emissions is not a reason to refuse development consent, unless the increase in carbon emissions resulting from the proposed Project are so significant that it would have a material impact on the ability of Government to meet its carbon reduction targets”. Regional policy Northamptonshire Climate Change Strategy 2017-2020 5.3.16. Northamptonshire Climate Change Strategy (Ref. 5-13) is overseen by the Northamptonshire Climate Change Officers Group (NCCOG) and provides an effective framework for the co-ordination of activities in the County. The annually updated Climate Change Strategy action plans recognise the need to establish key aims that will direct climate change efforts in Northamptonshire over the next three years. The aims are grouped and include but are not limited to; raising awareness of the issues of climate change, reducing emissions of greenhouse gases and plans to adapt to the impacts of climate change. GUIDANCE 5.3.17. The following guidance documents have been used during the preparation of this Chapter:  Highways England (2019) Design Manual for Roads and Bridges (DMRB) LA 114 Climate (Ref. 5-14);  IEMA Guidance on Assessing the GHG Emissions and Evaluating their Significance (Ref. 5-15);  TAG Unit A3 Environmental Impact Appraisal - Chapter 4 Greenhouse Gases (Ref. 5-16); and,  PAS 2080:2016 Carbon management in infrastructure (Ref. 5-1). STUDY AREA 5.3.18. The GHG assessment is not restricted by geographical area but instead includes any increase or decrease in emissions as a result of the Proposed Scheme, wherever they occur. This includes operational emissions (or reduction in emissions) resulting from the end-use of the Proposed Scheme and any shifts in transport modes/patterns that may occur. Such emissions include those for traffic using the Proposed Scheme as well as the surrounding regional road network. METHOD OF BASELINE DATA COLLATION Desk study 5.3.19. The baseline for operational end users’ emissions from the Proposed Scheme comprises the ‘Do Minimum’ scenario - a future baseline where the Proposed Scheme is not constructed, and emissions are generated by vehicles on the road network in the future.

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5.3.20. Emissions from the ‘Do Minimum’ scenario (the future baseline) were modelled in accordance with the Design Manual for Roads and Bridges, Volume 11, Section 3, Part 14 Climate; LA114 and WebTAG A3 (Ref.5-16). The modelling used data regarding vehicle movements sourced from the Proposed Scheme traffic model, covering the affected road network. Data published by the Department for Transport (Ref. 5-17) was then used to convert this traffic data to GHG emissions data. Site visits and surveys 5.3.21. For the purpose of this assessment, no site visits or surveys were required. ASSESSMENT METHODOLOGY 5.3.22. Emissions from the ‘Do Something’ scenario (the emissions from the road network with the road in place) were modelled in accordance with the Design Manual for Roads and Bridges, Volume 11, Section 3, Part 14 Climate; LA114 and WebTAG A3 (Ref.5-16) 5.3.23. The modelling used data regarding vehicle movements sourced from the Proposed Scheme traffic model, covering the strategic and local road network in the surrounding area of the Proposed Scheme. Data published by the Department for Transport (Ref. 5-17) was then used to convert this traffic data to GHG emissions data. Significance criteria 5.3.24. IEMA guidance (Ref. 5-15), suggests that all GHG emissions are significant in the absence of any significance criteria or defined threshold. 5.3.25. As there are currently no agreed thresholds for what level of GHG emissions is considered significant in an EIA, the significance of GHG emissions is assigned with reference to the magnitude of emissions, their context, guidance from IEMA and the use of professional judgement. 5.3.26. As climate change impacts are global in nature, it is not possible to link a specific project, with a specific environmental impact. In line with the NPSNN, significance of GHG impacts is assessed by comparing estimated GHG emissions arising from the Proposed Scheme with the respective UK carbon budget (Table 5-4), which have been set by the UK Government covering 2018 to 2032 (expressed in millions of tonnes of carbon dioxide equivalents (MtCO2e). 5.3.27. In terms of context, the carbon budgets presented are useful. However, the NPSNN sets out that “it is very unlikely that the impact of a road project will, in isolation, affect the ability of Government to meet its carbon reduction plan targets.” To provide additional context the emissions from 2015 within Northamptonshire and nationally are presented in Table 5-5 (Ref. 5-18).

Table 5-4 - UK Carbon Budgets

Carbon Budget Period UK Carbon Budget

Third: 2018-2022 2,544 MtCO2e

Fourth: 2023-2027 1,950 MtCO2e

Fifth: 2028-2032 1,725 MtCO2e

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Table 5-5 - GHG emissions in 2015 for in Northamptonshire and nationally

Category Northamptonshire (ktCO2) National (ktCO2)

A. Industry and Commercial 811.1 66,596.4 Electricity

B. Industry and Commercial Gas 416.5 34,486.4

C. Large Industrial Installations 0.4 38,954.2

D. Industrial and Commercial 238.0 17,376.5 Other Fuels

E. Agriculture 50.3 4,953.0

Industry and Commercial Total 1,516.3 162,366.5

F. Domestic Electricity 436.9 38,094.9

G. Domestic Gas 660.1 58,568.1

H. Domestic 'Other Fuels' 67.8 10,674.6

Domestic Total 1,164.8 107,337.6

I. Road Transport (A roads) 1,124.6 53,624.2

J. Road Transport (Motorways) 513.7 27,405.1

K. Road Transport (Minor roads) 478.7 40,495.3

L. Diesel Railways 31.4 2,050.8

M. Transport Other 31.2 2,245.1

Transport Total 2,179.7 125,820.4

N. LULUCF Net Emissions 3.6 -8,996.1

Grand Total 4,864.5 386,528.4

Population ('000s, mid-year 723.0 65,110.0 estimate)

Per Capita Emissions (t) 6.7 5.9

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Effect significance 5.3.28. The following terms have been used to define the significance of the effects identified and apply to both beneficial and adverse effects:  Major effect: where the Proposed Scheme could be expected to have a very significant effect (either positive or negative)  Moderate effect: where the Proposed Scheme could be expected to have a noticeable effect (either positive or negative)  Minor effect: where the Proposed Scheme could be expected to result in a small, barely noticeable effect (either positive or negative)  Negligible: where no discernible improvement or deterioration is expected as a result of the Proposed Scheme on receptors; and  No change: where no change is expected because of the Proposed Scheme on receptors. 5.3.29. Unless otherwise stated in the technical chapters of this ESA, effects that are classified as minor or above are considered significant. Effects classified as below minor are considered not significant. 5.4 BASELINE CONDITIONS EXISTING BASELINE AND FUTURE BASELINE 5.4.1. Average annual end-user emissions from traffic are presented in Table 5-6 for the baseline ‘Do Minimum’ scenario. Total end-use traffic emissions based on a 60-year operational life of the Proposed Scheme (2021-2080) are also presented. Table 5-6: Baseline operational stage emissions

Total GHG emissions for traffic in the strategic and local road network (tonnes of carbon dioxide equivalent; tCO2e) Scenario 2021 (operational Average per year Total (2021- 2031 (future year) year) (2021-2080) 2080)

Baseline (‘Do 4,030,551 3,676,571 3,709,019 222,541,140 Minimum’)

5.5 EFFECTS ARISING FROM CONSTRUCTION 5.5.1. As per the 2019 ES, the total emissions during the construction phase are estimated to be 2,273

tCO2e. 5.6 EFFECTS ARISING FROM OPERATION 5.6.1. The Proposed Scheme may result in changes to end-user traffic emissions throughout its operational life relative to the ‘Do Minimum’ scenario and these could be increases or decreases depending on the net effect on factors including traffic flows, vehicle type and speeds. Any increase in emissions and the corresponding concentrations of GHGs present in the atmosphere will contribute to climate change.

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5.6.2. Average annual end-user emissions from traffic are presented in Table 5-7 for the Proposed Scheme (i.e. the ‘Do Something’ scenario). Total end-use traffic emissions based on a 60-year operational life of the Proposed Scheme (2021 to 2080) are also presented. The equivalent values for the ‘Do Minimum’ scenario is provided for comparison. Table 5-7: Operational emissions

Total GHG Emissions for Traffic in the Strategic and Local Road Network (tCO2e)

Scenario 2021 (operational year) 2031 (future Average per year Total (2021 – 2080) year) (2021 – 2080)

Baseline Traffic Emissions (‘Do 4,030,551 3,676,571 3,709,019 222,541,140 Minimum’) (tCO2e)

Proposed Scheme (‘Do 4,030,719 3,676,315 3,708,802 222,528,098 Something’) (tCO2e)

Difference (tCO2e) 169 -256 -217 -13,042

5.6.3. Total regional traffic emissions for the operational lifespan of the Proposed Scheme (2021-2080)

would be -approximately 13,000 tCO2e less (<1% less) in the ‘Do Something’ scenario compared to

the baseline ‘Do Minimum’ scenario, this is equivalent to -217 tCO2e/year. The reduction of GHG emissions in the ‘Do Something’ scenario is associated with the lower number of vehicular kilometres travelled predicted by the traffic model. 5.6.4. Based on the results presented above, the magnitude of GHG emissions during operation is predicted to have minor positive significance. OPERATIONAL MITIGATION MEASURES 5.6.5. No mitigation measures are identified as the operation of the Proposed Scheme is predicted to lead to a reduction in GHG emissions over the lifespan of the Proposed Scheme. SIGNIFICANCE OF GHG EMISSIONS 5.6.6. The total estimated GHG emissions arising from the Proposed Scheme are presented in Table 5-8 for the operational stage (2021-2080) and the overall total for the design life (2020-2080). 5.6.7. The total emissions during each of the UK National Carbon Budget periods is presented and compared in percentage terms to the respective National budget, as shown in Table 5-8. The Third

Carbon Budget covering 2018 to 2022 is 2,544 million tCO2e. The Fourth Carbon Budget covering

2023 to 2027 is 1,950 million tCO2e. The Fifth Carbon Budget covering 2028 to 2032 is 1,725 million

tCO2e (the latest carbon budget agreed by the government).

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Table 5-8 – Proposed Scheme Impacts on Carbon Budgets

Stage / Timing Total GHG Emissions (tCO2e)

Operational phase (2021-2080) -13,042

Total for lifecycle (construction and -10,769 operation) (2020-2080)

Comparison of the Proposed Scheme GHG Emissions against UK National Carbon Budget

Total (tCO2e) during third Carbon Budget period (2018-2022) (% of +2,568 (<+0.01%) budget)

Total (tCO2e) during fourth Carbon Budget period (2023-2027) (% of -6.28 (<-0.01%) budget)

Total (tCO2e) during fifth Carbon Budget -1,027 (<-0.01%) period (2028-2032) (% of budget)

SUMMARY OF LIKELY RESIDUAL SIGNIFICANT EFFECTS 5.6.8. Emissions have been quantified for the operational phase of the Proposed Scheme in line with best practice. The magnitude of emissions has been contextualised, and this has been used to determine the significance of emissions due to the Proposed Development. 5.6.9. During the operational phase of the Proposed Scheme emissions are estimated to be of minor positive significance. No mitigation measures for the operation of the Proposed Scheme have been recommended.

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5.7 REFERENCES  Ref. 5-1: Infrastructure Carbon Review, HM Treasury, November 2013.  Ref. 5-2: United Nations Framework Convention on Climate Change, available at https://unfccc.int/  Ref. 5-3: United Nations (2015), Paris Agreement, available at https://unfccc.int/sites/default/files/english_paris_agreement.pdf  Ref. 5-4: Directive 2014/52/EU of the European Parliament and of the Council of 16 April 2014 amending Directive 2011/92/EU on the assessment of the effect of certain public and private projects on the environment (2014) https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014L0052&from=EN  Ref. 5-5: HM Government, Climate Change Act (2008) http://www.legislation.gov.uk/ukpga/2008/27/introduction  Ref. 5-6: Committee on Climate Change https://www.theccc.org.uk/  Ref. 5-7: Carbon Management in Infrastructure, British Standards Institution, May 2016.  Ref. 5-8: National Planning Policy Framework, Department for Communities and Local Government, March 2012.  Ref. 5-9: Distribution of Carbon Emissions in the UK: Implications for Domestic Energy Policy (page 20), Joseph Rowntree Foundation, March 2013.  Ref. 5-10: Cars and carbon dioxide webpage, Department for Transport, accessed online September 2017.  Ref. 5-11: National Policy Statement for National Networks, Department for Transport, December 2014.  Ref. 5-12: HM Government (2011), The carbon plan: delivering our low carbon future, available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/fil e/47613/3702-the-carbon-plan-delivering-our-low-carbon-future.pdf  Ref. 5-13: Northamptonshire County Council, Northamptonshire Climate Change Strategy (2017 – 2020), available at https://www.daventrydc.gov.uk/EasySiteWeb/GatewayLink.aspx?alId=45842  Ref. 5-14: Highways England (2019) DMRB LA 114 Climate  Ref. 5-15: IEMA (2017) Environmental Impact Assessment Guide to Assessing Greenhouse Gas Emissions and Evaluating their Significance [online] available at: https://www.iema.net/policy/ghg- in-eia-2017.pdf  Ref. 5-16: Department for Transport (2015) TAG Unit A3 Environmental Impact Appraisal available at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/638648/TAG_unit_ a3_envir_imp_app_dec_15.pdf  Ref. 5-17: DFT (2019) WebTAG data book https://www.gov.uk/government/publications/tag-data- book and DFT (2018) Road Statistics https://www.gov.uk/government/collections/road-traffic- statistics  Ref. 5-18: DBIS, 2017, UK local and regional CO2 emissions, https://www.gov.uk/government/statistics/uk-local-authority-and-regional-carbon-dioxide- emissions-national-statistics-2005-2015

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6 LANDSCAPE AND VISUAL

6.1 INTRODUCTION 6.1.1. As set out in Chapter 3: Approach to the EIA (Volume II of the ESA), the changes to the Proposed Scheme are too small in relation to the scale of the works as a whole to have any effect on the findings of significance reported in Chapter 11: Landscape and Visual (Volume II of the 2019 ES). However, the changes in baseline conditions since the 2019 ES was written alter the effect on one visual receptor and introduce two new visual receptors. 6.1.2. This chapter reports the assessment of likely significant effects on visual amenity arising from the Proposed Scheme on these three receptors considering the baseline conditions that exist in May 2020. 6.1.3. This chapter follows the methodology presented in the 2019 ES, please refer to Chapter 11: Landscape and Visual (Volume II of the 2019 ES) for further details. It provides supplementary and revised information only and therefore needs to be read in conjunction with Chapter 11: Landscape and Visual (Volume II of the 2019 ES). 6.2 SCOPE, ASSUMPTIONS AND LIMITATIONS 6.2.1. For the purposes of this chapter, it has been assumed that is assumed that:  The development known as Buckton Fields West (currently under construction – please refer to Table 3.1 for further information) contains residential properties which are currently occupied; and  The development known as Welford Road (currently under construction – please refer to Table 3.1 for further information) contains residential properties which will shortly be occupied. 6.2.2. To carry out a ‘worst-case scenario’ assessment, it has been assumed that the new residents (and thus new receptors) are unaware of the Proposed Scheme: they have been classed as being of high sensitivity. In reality, it is likely that they would be aware of development occurring all round, including the Proposed Scheme, and would thus be less sensitive to the impact of change; they would probably be of medium sensitivity. 6.2.3. This Chapter has been limited by the Covid-19 movement restrictions in force at the time of writing. It is based on a desk-based assessment, no site visit has been undertaken by a landscape architect to confirm the precise extent of visibility from the new developments or the change in visual amenity experienced by the existing receptors. However, the author team carried out site visits to inform the 2019 ES and therefore have knowledge of key views and receptors. In addition, a worst-case scenario approach has been adopted. 6.3 METHODOLOGY 6.3.1. Please refer to Section 11.3 (Chapter 11: Landscape and Visual (Volume II of the 2019 ES)) for details of the methodology and approach in carrying out the landscape and visual impact assessment.

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6.4 BASELINE CONDITIONS UPDATE TO EXISTING CONDITIONS 6.4.1. At the time of writing the 2019 ES (April/May 2019), most of the housing development east of the river valley stopped at the district boundary. The development known as Buckton Fields East, which abutted the Northampton Borough boundary, was under construction and a number of properties had been occupied. 6.4.2. Since submission of the 2019 ES, construction work has started at two further residential developments known as Buckton Fields West and Welford Road. Both developments were considered as committed developments within the 2019 ES, please refer to Chapter 5: Approach to EIA (Volume II of the ES). Please also refer to Figure 3.1 – Committed Developments (Volume IV of the ES) for the location of these developments. 6.4.3. Consultation with Daventry District Council (DDC) as part of the EIA Scoping process (please refer to Section 3.4 for further information) has identified that a small number of properties at Buckton Fields West are now occupied, please refer to Figure 6.1

Figure 6-1: MasterMap extract showing development of Buckton Fields West and Welford Road (March 2020)

© Crown copyright and database rights 2020, Ordnance Survey 0100031673 6.4.4. The construction of Buckton Fields West and Welford Road alters the visual amenity of the existing properties on the north side of Sherwood Avenue and Fallow Walk. It introduces two new residential receptor groups which will be referred to as residential receptors R22 and R23 as part of this assessment. Please refer to Figure 6.2 - Visual Effects Residential (Volume IV of the ESA). 6.4.5. It is assumed that the view from the Buckton Fields East development would not change in the immediate future as Buckton Fields West is being built out from the bottom of the hill.

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REVISED BASELINE CONDITIONS Visual Residential receptors 6.4.6. Chapter 11: Landscape and Visual (Volume II of the 2019 ES)2019 LVIA stated that: “The main area of residential receptors is to the east of the Proposed Scheme, where it would be clearly visible from the houses that back on to the Brampton Valley Way, albeit for some properties with the view from the ground floor partly screened or filtered by garden fences and the trees and shrubs along the Brampton Valley Way”. 6.4.7. This remains the case. It also stated “There would be views of the northern part of the Proposed Scheme from properties on the northern edge of Spring Park and White Hills, at least until such time as the fields to the north are built out. There would also be views from the new houses in these fields”. 6.4.8. The “fields to the north” previously referred to are now being built out. The changed baseline now means that:  There would be limited views of the northern part of the Proposed Scheme from properties on the northern edge of Spring Park and White Hills (receptor R7), through gaps between the houses of Buckton Fields West.  There would be clear views of the Proposed Scheme from the new properties south of Welford Road (new receptor R2X), and clear views of the Proposed Scheme, over the rooftops of the houses below, from the new properties at the western end of Buckton Fields West (new receptor R2Y). 6.5 MITIGATION 6.5.1. Embedded (primary) mitigation forming part of the Proposed Scheme design is shown on Figure 6.3 - Landscape Mitigation and Preliminary Design (Volume IV of the ESA)4 and includes: VISUAL MITIGATION 6.5.2. The Proposed Scheme includes:  Woodland planting on the embankments to the railway bridge, on the wider parts of the embankments on the Main Carriageway, and east of the Sandy Lane roundabout to substantially reduce views of the Proposed Scheme and traffic on it from many sensitive visual receptors;  Hedgerow with hedgerow trees on the Main Carriageway across the valley, on the link to the north and on the east side where the embankments are too narrow for woodland establishment, to filter views of the Proposed Scheme and traffic on it from many sensitive visual receptors; and  Clumps of woodland to act as a visual buffer to the golf course. 6.5.3. Breaks in the woodland on the west side, and the mix of woodland and hedgerow planting on the west side are designed to avoid a tunnel effect for road users.

4 Readers should note that Figure 6.3 - Landscape Mitigation and Preliminary Design (Volume IV of the ESA) supersedes Figure 11.7 - Landscape Mitigation and Preliminary Design (Volume IV of the ES).

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6.5.4. Soil conditions are critical for the successful long-term establishment of woodland vegetation on the embankments. Uncompacted soils at appropriate depths will be included for all woodland planting areas, and the specification will require the decompaction of subsoils under planting areas, particularly on the road embankments. LANDSCAPE MITIGATION 6.5.5. Woodland and hedgerow planting would comprise locally native species such as oak, field maple, lime, silver birch, blackthorn, elder, hawthorn and crab apple, and would include a small proportion of disease-resistant elms. 6.5.6. Final species selection will be subject to ecological advice, lineside planting guidance for near the railway and consultation with Natural England. 6.5.7. Where not planted, embankment slopes and other areas forming part of the final Proposed Scheme, such as around the attenuation ponds and across the flood replacement storage areas, will be seeded with species-rich grassland. Species mixes are to be determined to suit the anticipated soil and ecological conditions. 6.5.8. Floodplain marsh and reed-beds would be established on the margins of the attenuation ponds and in any permanent damp areas of the flood storage replacement areas. 6.6 VISUAL ASSESSMENT 6.6.1. Visual Effect Schedules were prepared for the receptors identified in the 2019 ES, please refer to Table 11-3 (Chapter 11: Landscape and Visual (Volume II of the 2019 ES)). 6.6.2. Table 6.1 is an addendum Visual Schedule to be read in conjunction with Table 11-3 of the 2019 ES. Table 6.1 sets out the revised effects on Receptor R7 and assesses the two new residential receptor groups, R22 and R23. Please refer to Figure 6.2 - Visual Effects Residential (Volume IV of the ESA).

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Table 6-1: Visual effects schedule

Ref. Receptors Existing view Change in view and magnitude of Significance of and impact effect sensitivity

RESIDENTIAL RECEPTORS

R7 Northern There is currently a The Proposed Scheme would be Slight to Moderate (revised) edge of view of the new partially visible between the new adverse Spring Park housing houses, at grade or on a low (temporary) during High development under embankment. construction (not sensitivity way at Buckton Construction activity would be visible significant). Fields West, with a but, in the context of the recently Slight adverse partial view changed foreground to the view, not (permanent) on between the new particularly intrusive. completion (not houses to the On completion, the Proposed significant), none Brampton valley in Scheme and traffic on it would be after 15 years the near middle- visible between the new houses, with because of ground beyond the vehicle lights and street lighting changes to the existing forming part of a backdrop to a night- intervening Northampton Road. time view that would include lights baseline (not and lighting in the foreground. significant). By year 15, it is predicted that the Slight adverse Buckton Fields West development (operational) on would be complete and there would completion (not be little or no view of the Proposed significant), none Scheme. after 15 years because of Minor impact during construction and changes to the on completion, falling by year 15 to intervening no impact because of new housing baseline (not development in the foreground. significant).

R22 Welford Rd. An open and The Proposed Scheme would cross Very large (new) development slightly elevated the view in the near middle distance, adverse High rural view across on a slight embankment. (temporary) during sensitivity the Brampton valley Construction activity would be a construction enclosed by the noticeable intrusion across much of (significant). rising ground and the view. Large adverse tree belts of the golf On completion, the Proposed (permanent) on course. For some, Scheme and traffic on it would be a completion the view is partly noticeable new element across the (significant), filtered by other whole view, with vehicle lights falling to moderate houses as part of intrusive in the night-time view. adverse after 15 the same years (significant). development. By year 15, the roadside hedges and trees would have reduced the extent Large adverse to which traffic and vehicle lights (operational) on would be visible and would help completion integrate the Proposed Scheme into (significant), the landscape. falling to moderate adverse after 15 Major impact during construction and years (significant). on completion, falling to moderate at year 15.

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Ref. Receptors Existing view Change in view and magnitude of Significance of and impact effect sensitivity

R23 Buckton An open and The Proposed Scheme would cross Large adverse (new) Fields (West) slightly elevated the view in the near middle distance, (temporary) during development rural view across on a slight embankment, potentially construction High the Brampton valley partially screened by the houses (significant). sensitivity over the rooftops of below Welford Road. Moderate to large the new Welford Construction activity would be clearly adverse Road development, visible across much of the view. (permanent) on enclosed by the On completion, the Proposed completion rising ground and Scheme and traffic on it would be a (significant), tree belts of the golf new element across the whole view, falling to moderate course. For some, visible to the north and between the adverse after 15 the view partly houses. years (significant). filtered by other Large adverse houses as part of By year 15, the roadside hedges and (operational) on the same trees would have reduced the extent completion development. to which traffic and vehicle lights would be visible and would help (significant), integrate the Proposed Scheme into falling to moderate the view. adverse after 15 years (significant). Moderate impact during construction and on completion, falling to minor at year 15.

6.7 CUMULATIVE ASSESSMENT INTRODUCTION 6.7.1. The 2019 LVIA stated: “...north-west of Northampton is developing rapidly, with a number of large housing developments surrounding the Proposed Scheme. To the east of the Site, the Buckton Fields development of over 1,000 houses will occupy the land to the north of Spring Park, effectively extending the northern edge of built-up area to Brampton Lane. To the south of the Site, Dallington Grange, a 3,000-home development, will occupy the currently open land between Kings Heath and Dallington Heath. Buckton Fields is currently part developed and it is anticipated that construction will have commenced at Dallington Grange by the time the Proposed Scheme opens. Both schemes are anticipated to be complete within 15 years. The Proposed Scheme is part of the infrastructure enabling the development of Dallington Grange and it is likely that it and the two housing developments described above will be perceived by most observers as part of the same overall development and expansion of the town”. 6.7.2. Since preparation of the 2019 ES, part of Buckton Fields West is now complete, and Welford Road is now under construction.

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CUMULATIVE VISUAL ASSESSMENT 6.7.3. Cumulative Visual Effect Schedules were prepared for the receptors identified in the visual impact assessment of the 2019 ES, please refer to Table 11-4 ((Chapter 11: Landscape and Visual (Volume II of the 2019 ES)). Table 6-2 is an addendum Schedule to be read in conjunction with Table 11-4 of the 2019 ES and sets out the revised effects on Receptor R7 and new effects on residential receptor groups, R22 and R23.

Table 6-2: Cumulative Visual effects schedule

Ref. Receptors Existing view Difference in view Significance of and compared to the Visual cumulative effect sensitivity Effects Schedule (Table 11-3)

RESIDENTIAL RECEPTORS

R7 Northern edge There is currently a broad The build-out of the None of Spring Park open rural view from the rear remaining parts of the High of approximately 30 houses Buckton Fields West sensitivity which are angled to view to the development would northwest, with the Brampton entirely occupy the view, valley in the near middle- such that the Proposed ground beyond the existing Scheme would likely no Northampton Road. longer be visible it would have no additional (and thus cumulative) effect.

R22 Welford Rd. An open and slightly elevated Committed developments None (new) development rural view across the Brampton would not affect the view. High valley enclosed by the rising sensitivity ground and tree belts of the golf course. For some, the view partly filtered by other houses as part of the same development.

R23 Buckton Fields An open and slightly elevated Build-out of the remaining Slight adverse (new) (West) rural view across the Brampton parts of the Buckton (not significant) development valley over the rooftops of the Fields West development High new Welford Road would occupy what is sensitivity development, enclosed by the currently a rural part of the rising ground and tree belts of view (northwest from the the golf course. For some, the receptor group). view partly filtered by other Minor cumulative impact houses as part of the same during construction, on development. completion and at year 15.

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7 NOISE AND VIBRATION

7.1 INTRODUCTION 7.1.1. This chapter reports the outcome of the assessment of likely significant effects arising from the construction and operation of the Proposed Scheme in terms of noise and vibration. This chapter supersedes Chapter 13: Noise and Vibration (Volume II of the 2019 ES). 7.1.2. This chapter describes the assessment methodology and the baseline conditions relevant to the assessment. A summary of the likely impacts has been presented, along with mitigation measures required to avoid, prevent or reduce any likely significant adverse effects. Residual effects and any required monitoring after mitigation measures have been employed are also described. 7.1.3. This chapter (and its associated appendices) is intended to be read as part of the 2019 ES and ESA. A glossary of acoustic terminology is included in Appendix 7.1: Glossary of Acoustic Terminology (Volume III of the ESA). 7.2 SCOPE, ASSUMPTIONS, AND LIMITATIONS CONSULTATION 7.2.1. Table 7.1 provides a summary of the consultation activities undertaken in support of the preparation of this chapter.

Table 7-1: Summary of Scoping Responses

Body / Individual / stat Meeting dates and other forms Summary of outcome of organisation body / organisation of consultation discussions

Northampton Gavin Smith EIA Scoping Addendum (20 April Email response (04 May 20) Borough (Environmental 2020) – setting out proposed confirming that NBC has no Council (NBC) Health) assessment methodology for comment regarding the noise and vibration proposed assessment methodology

Daventry Mike Jephcott EIA Scoping Addendum (20 April No comments on the scope District Council (Environmental 2020) – setting out proposed of the assessment. (DDC) Health) assessment methodology for noise and vibration

SCOPE OF THE ASSESSMENT 7.2.2. The scope of the assessment follows the methodology set-out in the EIA Scoping Addendum Report (Appendix 3.6 (Volume III of the ESA)). Further information can be found in Chapter 3: Approach to the EIA (Volume II of the ESA). 7.2.3. The EIA Scoping Addendum Report noted that the noise and vibration assessment would be guided by the general principles of the Design Manual for Roads and Bridges (DMRB) LA 111 (Ref. 7-1). It should be noted, however, that DMRB LA 111 has been applied in a proportionate manner, with adjustments made to meet the assessment aims and to give due consideration to aspects that are considered particularly relevant and to give less or no emphasis to those aspects that do not usefully inform the assessment aims.

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7.2.4. Guided by DMRB LA 111 and the EIA Scoping Addendum (and responses), and following a review of the previous assessment presented in the 2019 ES, elements have been scoped-in and scoped- out of the assessment, as summarised in the following sections. Elements Scoped-out of the Assessment 7.2.5. The elements shown in Table 7.2 are not considered to give rise to likely significant effects as a result of the Proposed Scheme and have therefore not been considered within the ESA:

Table 7-2: Elements Scoped-out of the Assessment

Element scoped out Justification

Ground-borne DMRB LA 111 advises (in paragraph 1.4) that operational vibration should be “scoped out vibration from of the assessment methodology as a maintained road surface will be free of irregularities the Proposed as part of project design and under general maintenance, so operational vibration will not Scheme have the potential to lead to significant adverse effects”.

Noise and Whilst existing receptors close to, and on routes leading to, the Proposed Scheme may vibration from experience some noise from the traffic generated by the construction works, the effect is construction unlikely to be significant compared to noise from other sources (for example, the noise traffic generated by the on-site activities, for receptors close to the Proposed Scheme and from existing traffic, for receptors along routes leading to the Proposed Scheme). Nevertheless, construction traffic movements should not be uncontrolled, and so the route(s) to and from the Site should be agreed with the Local Planning Authority, in this case Northamptonshire County Council, to minimise effects on local receptors.

Elements Scoped-in to the Assessment Construction Phase 7.2.6. The following elements are considered to have the potential to give rise to likely significant effects at sensitive receptors during the construction of the Proposed Scheme and have therefore been considered within the ESA:  Noise from on-site construction activities; and  Vibration from on-site construction activities. Operation Phase 7.2.7. The following elements are considered to have the potential to give rise to likely significant effects at sensitive receptors during the operation of the Proposed Scheme and have therefore been considered within the ESA:  Noise from traffic using the Proposed Scheme; and  Noise from changes in traffic on existing roads (also described later as the wider road network) as a result of the Proposed Scheme.

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LIMITATIONS AND ASSUMPTIONS 7.2.8. The following key limitations and assumptions are associated with the assessment that has been undertaken.  The 2019 ES included details of a noise survey undertaken in December 2018. No new survey has been undertaken to inform this ESA because it is considered unlikely that the baseline noise climate would have changed significantly in the last 18-months (save for the unprecedented and on-going situation caused by the Covid-19 pandemic).  The assessment is based on a ‘Do-Something’ (DS) scenario that includes for the effect of the Proposed Scheme and all cumulative schemes. The effects of these cumulative schemes are not included within the ‘Do-Minimum’ (DM) scenarios. The reported effects therefore represent a cumulative assessment of effects arising within the study area.  The traffic data used in the operational road traffic noise predictions have been applied in a proportionate manner, in line with the DMRB LA 111 guidance.  It has been necessary to make a number of assumptions in the operational noise modelling and prediction process. It should be noted that at the core of the assessment is an appraisal of noise level changes, and the same assumptions have been applied in both the DM and DS noise models. The noise model settings are described in Appendix 7.2: Noise Model (Volume III of the ESA) and assumptions include: • building and storey heights. As a starting point, residential building heights have been taken to be 8 m high, although building footprints below 25 m2 have been taken to be 3 m high. Final adjustments to heights (up and down) have been made using web-based street-view and aerial photography (Ref. 7-2). • the absorption coefficient assigned to buildings (α = 0). • the default ground absorption (α = 0.75).  Night-time (and daytime) noise level predictions have been undertaken by application of day to night conversion factors. Method 3 as described within TRL Limited Project Report PR/SE/451/02 (Ref. 7-3) has been adopted. The correction has been applied based on all roads being non- motorways (i.e. local urban/suburban routes).  The type of road surface assumed can have a notable influence on noise predictions. However, as there are no roads with an assigned speed above 75 kph in the study area under any scenario, a surface correction of -1.0 dB has been applied to all roads in all scenarios.  Any traffic speeds below 20 kph have been increased to this threshold.  The traffic model only includes the more significant roads in the highway hierarchy and so, in turn, does the noise model. Therefore, to counter the tendency for under-predicting noise levels in areas that are remote from these more significant roads, a ‘noise floor’ of 42.7 dB has been included in the noise model (see Section 7.4) and particularly paragraph 7.4.9 onwards).  At this stage the precise details of the construction work, including associated plant, working hours, programme and methodology are not known. The construction noise and vibration assessments are therefore under-pinned by a number of stated assumptions, which have been informed by information provided by the Design Team. Assumptions include the number and type of plant, source noise levels and operating duration and location (see Section 7.5).

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7.3 METHODOLOGY 7.3.1. The various legislative, policy and guidance documents tabulated below have been used to shape the assessment of noise and vibration effects arising from the Proposed Scheme. Further details are provided in Appendix 7.3: Legislation, Policy and Guidance (Volume III of the ESA). LEGISLATIVE FRAMEWORK  Noise Insulation Regulations (NIR), 1975 (as amended) (Ref. 7-4)  Environmental Noise Directive (END) 2002/49/EC and Environmental Noise (England) Regulations 2006 (as amended) (Ref. 7-5)  The Control of Pollution Act (CoPA), 1974 (Ref. 7-6)  European Commission (2014) Environmental Impact Assessment Directive (EIA) 2014/52/EU (Ref. 7-7) NATIONAL POLICY  Noise Policy Statement for England (NPSE), 2010 (Ref. 7-8)  National Planning Policy Framework (NPPF), 2019 (Ref. 7-9)  Planning Practice Guidance, 2019 (Ref. 7-10) TECHNICAL GUIDANCE  DMRB Volume 11, Section 3, Part 7, LA 111 Noise and Vibration. Highways England, Transport Scotland, Welsh Government, Department for Infrastructure. Revision 2, May 2020 (Ref. 7-1)  Calculation of Road Traffic Noise (CRTN). Department of Transport and Welsh Office. 1988 (Ref. 7-11)

 Converting the UK traffic noise index LA10,18h to EU noise indices for noise mapping. P G Abbott and P M Nelson (TRL Limited). Project Report PR/SE/451/02. 2002 (Ref. 7-3)  British Standard 5228 Code of practice for noise and vibration control on construction and open sites. Part 1: Noise and Part 2: Vibration. BS 5228:2009+A1:2014. 2014 (Ref. 7-12 and Ref. 7-13)  Guidelines for Community Noise. World Health Organisation. 1999 (Ref. 7-14)  Night Noise Guidelines for Europe. World Health Organisation. 2009 (Ref. 7-15) 7.3.2. Current noise policy in England is based on the NPSE, which through the effective management and control of environmental noise within the context of government policy on sustainable development, aims to:  Avoid significant adverse impacts on health and quality of life;  Mitigate and minimise other adverse impacts on health and quality of life; and  Contribute to improvements to health and quality of life, where possible. 7.3.3. The Explanatory Note to the NPSE assists in the definition of significant adverse and adverse with the following concepts:  NOEL – no observed effect level. This is the level below which no effect can be detected. In simple terms, below this level, there is no detectable effect on health and quality of life due to the noise;  LOAEL – lowest observed adverse effect level. This is the level above which adverse effects on health and quality of life can be detected; and

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 SOAEL – significant observed adverse effect level. This is the level above which significant adverse effects on health and quality of life occur. 7.3.4. There are no set values for the NOEL, LOAEL and SOAEL in government policy or guidance, the guidance advises that these values are different for different noise sources, for different receptors and at different times and should be defined on a strategic or project basis accounting for the specific features of that area, source or project. The derived values for the effect levels that have been adopted for the assessment of the Proposed Scheme are set out in the following section. 7.3.5. The key objectives of this assessment are to determine whether any significant effects are likely to arise in terms of noise and vibration and if any such effects are adverse, to investigate and recommend measures to mitigate and minimise those significant effects. STUDY AREA Construction Noise and Vibration 7.3.6. DMRB LA 111 includes the following advice on the extent of suitable study areas for temporary construction activities, although it is acknowledged that study areas can be varied for individual projects:  construction noise study area: “A study area of 300m from the closest construction activity is normally sufficient to encompass noise sensitive receptors” (DMRB LA 111, paragraph 3.5, Note 1)  construction vibration study area “A study area of 100m from the closest construction activity with the potential to generate vibration is normally sufficient to encompass vibration sensitive receptors” (DMRB LA 111, paragraph 3.29, Note 1) 7.3.7. For this assessment of construction activities, the study areas as noted in the bullet points above have been adopted (i.e. 300 m for noise and 100 m for vibration). Operational Road Traffic Noise 7.3.8. DMRB LA 111 includes (in paragraph 3.44, Note 1) the following advice on the extent of a suitable study area for the operational road traffic assessment, although again it is acknowledged that the study area can be varied for individual projects. An operational study area defined as the following can be sufficient for most projects, but it can be reduced or extended to ensure it is proportionate to the risk of likely significant effects: 1) the area within 600m of new road links or road links physically changed or bypassed by the project; 2) the area within 50m of other road links with potential to experience a short term BNL5 change of more than 1.0dB(A) as a result of the project.

5 The Basic Noise Level (BNL) is described in the Calculation of Road Traffic Noise (CRTN) (Ref. 7-11). It does not relate to any specific receptor, but rather is a measure of source noise, at a reference distance of 10 m from the nearside carriageway edge of a specific length of highway. It is determined by obtaining the estimated noise level from the 18-hour traffic flow and then applying corrections for vehicle speed, percentage of heavy vehicles, gradient and road surface as described in CRTN.

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7.3.9. For this assessment of operational road traffic and in line with DMRB LA 111 guidance, the main study area has been determined based on a 600 m buffer around the Proposed Scheme and the existing road links made redundant by the Proposed Scheme. These links and the 600 m buffer are shown in Figure 7-1 in Appendix 7-4: Figures (Volume III of the ESA). 7.3.10. There are a number of road links in the vicinity of the Proposed Scheme with the potential to experience a short-term basic noise level (BNL) change of more than 1 dB(A) as a result of the Proposed Scheme. A number of these are along Brampton Lane to the east of the Proposed Scheme. The 2019 ES reported significant adverse effects in this area and because of this, the 50 m buffer around other roads links as identified in DMRB LA 111 guidance (point 2 in paragraph 7.3.8 above), has cautiously been extended (i.e. to 100 m) to ensure that all significant effects are captured and reported. For consistency, this extended buffer has been applied to all of these other links with potential to experience a short-term change in noise of more than 1.0 dB(A) as a result of the Proposed Scheme. The other links and the 100 m buffer are shown in Figure 7-2 in Appendix 7-4: Figures (Volume III of the ESA). 7.3.11. DMRB LA 111 provides (in paragraph 3.51.2) advice on the calculations required within each of these buffers. NOTE 1 CRTN calculations of noise levels change at noise sensitive receptors are likely to be required within 600m of new road links or roads physically changed by the project. NOTE 2 Calculations of BNL change are likely to be required for noise sensitive receptors not covered by calculations of noise level change, and within 50m of road links where noise levels change by 1dB(A) in the short term or 3dB(A) in the long term. NOTE 3 Where BNL changes show likely significant effects for noise sensitive receptors along road links, it can be appropriate to extend CRTN calculations to include these road links. 7.3.12. Since there is potential for significant effects along the road links where noise levels change by more than 1 dB(A) as a result of the Proposed Scheme, it is considered appropriate that detailed, receptor specific, CRTN calculations are made within the 100 m buffer. Consequently, the two buffers have been joined together and detailed road traffic noise calculations have been made at all receptors within this combined study area, as allowed by DMRB LA 111. This combined operational road traffic noise study area is shown in Figure 7-3 in Appendix 7-4: Figures (Volume III of the ESA). METHOD OF BASELINE DATA COLLATION 7.3.13. The baseline noise levels can be described through measurements and predictions. It is not possible to measure at every receptor nor to measure future conditions, therefore the majority of the assessment is based on predicted noise levels. However, survey data can be used to validate the noise model. 7.3.14. The method adopted to measure the baseline conditions is described below, whilst the details regarding the predicted noise levels are given later in this chapter. In the absence of any known existing issues with vibration – road traffic vibration not typically being a significant concern and having been scoped out of the assessment – no baseline vibration measurements were undertaken. Site Visits and Surveys 7.3.15. Satellite imagery was initially used to determine the noise survey locations. The measurement locations were selected based on proximity of the noise sensitive receptors to the Proposed Scheme, existing dominant noise sources and site access availability.

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7.3.16. Where secure locations for leaving equipment unattended were not available, locations for short- term attended monitoring were identified. 7.3.17. The survey was undertaken during December 2018. A sound level meter was deployed at each of the measurement locations described in Table 7.3 and Table 7.4 and shown in Figure 7-4 in Appendix 7.4: Figures (Volume III of the ESA). The unattended long-term measurements were conducted between Tuesday 4 and Tuesday 11 December 2018. The attended short-term measurements were completed between Thursday 6 and Friday 7 December 2018. Photographs are included in Appendix 7.5: Photographs (Volume III of the ESA).

Table 7-3: Baseline Noise Survey Locations (Unattended Long-term)

Height above Approximate Pos. the ground distance to the Description of noise Location no. (measurement centre of the environment condition) Proposed Scheme

LT1 In field north of Grange Farm 3 m (free-field) 102 m Occasional trains on the near the railway railway nearby. Other sources included distant road traffic and noises from the farm

LT2 Attached to a fence near the 2 m (free-field) 235 m Combination of activity at dwellings at Grange Farm the farm and occasional trains on the railway

LT3 On the north-east boundary 1.5 m (free-field) 303 m Distant traffic on Sandy of the Brampton Heath Golf Lane and infrequent Centre and south of Sandy distant activities at the Lane golf course

LT4 On the east boundary of the 1.5 m (free-field) 44 m The location was Brampton Heath Golf Centre dominated by the distant and north of the railway traffic and infrequent activity at the golf course

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Table 7-4: Baseline Noise Survey Locations (Attended Short-term)

Height above Approximate Pos. the ground distance to the Description of noise Location no. (measurement centre of the environment condition) Proposed Scheme

ST1 Near cycle path through 1.5 m (free-field) 270 m Combination of distant Kingsthorpe North Meadows, traffic, birdsong, bikers behind residential properties and pedestrians on Garsdale near A5199 Welford Road

ST2 In a lay-by, 5 metres away 1.5 m (free-field) 310 m The dominant noise from Northampton Road, source was traffic on near three-way junction of A5199 Welford Road A5199 Northampton Road and Brampton Lane

7.3.18. The equipment used during the survey is listed in Appendix 7.6: Noise Monitoring Equipment (Volume III of the ESA). The meters were calibrated before and after each set of measurements using the acoustic calibrators detailed in Appendix 7.6: Noise Monitoring Equipment (Volume III of the ESA), which had been calibrated within the preceding twelve months by a Accreditation Service (UKAS) accredited calibration laboratory. Each meter was found to be equal or less than 0.5 dB adrift from the pre-measurement calibration, which is within the limit (of 1 dB) stated in Appendix 2 of CRTN (Ref. 7-11). 7.3.19. No abnormal traffic conditions were noted at the time of installation and collection of monitoring equipment. Weather conditions were relatively benign, being dry most of the time with generally light winds, although some stronger winds were encountered on Friday 7 and Saturday 8 December. Overall conditions were considered typical for the time of year and largely suitable for the measurement of environmental noise. Weather data have been obtained from a station in Church Brampton (ref. IUNITEDK273) (Ref 7-16) and a summary is included in Appendix 7.7: Weather Data (Volume III of the ESA). 7.3.20. The full noise survey results (in terms of hourly periods for the long-term data) are presented in Appendix 7.8: Baseline Noise Survey Results (Volume III of the ESA), whilst a summary of the results is presented in Section 7.4. ASSESSMENT METHODOLOGY 7.3.21. Although the Proposed Scheme does not form part of the national network of major roads managed by Highways England, the de facto guidance document for the assessment of both temporary construction and permanent operational noise and vibration impacts associated with the Proposed Scheme, is DMRB LA 111 revision 2 (May 2020). The assessment of temporary construction phase effects is supplemented by the guidance in British Standard 5228. 7.3.22. Since the NPSE was published in 2010, more emphasis has been placed on the effects of noise on health and wellbeing, rather than the bother caused by noise as was previously the case. This has necessitated an evolution in the approach to the assessment of road traffic noise, particularly with respect to determining the significance of likely effects.

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7.3.23. National noise policy aims to avoid significant adverse noise effects. A noise level above the SOAEL will be noticeable and disruptive and/or can cause adverse health effects. A noise level above the LOAEL, but below the SOAEL, will increasingly cause changes in behaviour. 7.3.24. The term significant environmental effect is used within the EIA Directive 2014/EU to describe an environmental effect caused by a scheme that is of sufficient magnitude that it should be considered by the decision makers. Consequently, this chapter aims to identify whether significant adverse effects are likely to arise as a result of the Proposed Scheme and if so, the mitigation measures that might be employed to avoid, prevent or reduce any such effects. Construction Noise Predictions 7.3.25. Construction noise levels have been predicted at sample receptors within the study area following the methodology set out in Annex F of BS 5228-1:2009+A1:2014. Significance 7.3.26. The adopted methodology follows the guidance in DMRB LA 111, which draws heavily on BS 5228:2009+A1:2014. 7.3.27. Two key aspects underpinning the adopted methodology are:  the baseline noise levels, which might be determined using noise measurements and/or noise predictions; and  threshold levels determined as per BS 5228-1: 2009+A1:2014 Section E3.2 and Table E.1 BS 5228-1:2009+A1:2014. 7.3.28. The BS 5228-1 ABC method of assessing the potential significance of construction phase noise (Table E1 in the Standard) is reproduced in Table A7-8 in Appendix 7.3: Legislation, Policy and Guidance and included below for ease of reference. The table and associated notes describe how the existing ambient noise level is used to determine relevant threshold categories for the construction noise assessment.

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Table 7-5: Example Threshold of Potential Significant Effect at Dwellings

Threshold value, in decibels (dB LAeq,T) Assessment category and threshold value period Category A (A) Category B (B) Category C (C)

Night-time (23:00 − 07:00) 45 50 55

Evenings and weekends (D) 55 60 65

Daytime (07:00 − 19:00) and 65 70 75 Saturdays (07:00 − 13:00)

Notes: [1] A potential significant effect is indicated if the LAeq,T noise level arising from the site exceeds the threshold level for the category appropriate to the ambient noise level. 2] If the ambient noise level exceeds the Category C threshold values given in the table (i.e. the ambient noise level is higher than the above values), then a potential significant effect is indicated if the total LAeq,T noise level for the period increases by more than 3 dB due to site noise. [3] Applied to residential receptors only. (A) Category A: threshold values to use when ambient noise levels (when rounded to the nearest 5 dB) are less than these values. (B) Category B: threshold values to use when ambient noise levels (when rounded to the nearest 5 dB) are the same as category A values. (C) Category C: threshold values to use when ambient noise levels (when rounded to the nearest 5 dB) are higher than category A values. (D) 19:00 – 23:00 weekdays, 13:00 – 23:00 Saturdays and 07:00 – 23:00 Sundays.

7.3.29. Once the baseline noise level and threshold category have been identified, the LOAEL and the SOAEL can be determined in accordance with the guidance in Table 3.12 of DMRB LA 111, as reproduced below in Table 7.6.

Table 7-6: LOAELs and SOAELs for Construction Noise

Time period LOAEL SOAEL

Daytime (0700-1900 weekday Baseline noise levels LAeq,T Threshold level determined as per and 0700-1200 Saturdays) BS 5228-1:2009+A1:2014 Section Night (2300-0700) E3.2 and Table E.1 BS 5228-1:2009+A1:2014 Evenings and weekends (time periods not covered above)

7.3.30. The next step is to calculate the construction noise levels. Once the construction noise levels have been predicted at each sample receptor, they are assigned a magnitude of impact in accordance with the thresholds in Table 3.16 of DMRB LA 111, which is reproduced as Table A7-2 in Appendix 7.3: Legislation, Policy and Guidance and included below for ease of reference.

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Table 7-7: Magnitude of Impact and Construction Noise Descriptions

Magnitude of impact Construction noise level

Major Above or equal to SOAEL +5 dB

Moderate Above or equal to SOAEL and below SOAEL +5 dB

Minor Above or equal to LOAEL and below SOAEL

Negligible Below LOAEL

7.3.31. Minor or negligible impacts would normally be considered not significant. However, this could be varied depending on acoustic context and local circumstances. 7.3.32. Generally, major or moderate magnitudes of impact would be considered significant effects if they occur for a duration exceeding:  10 or more days or nights in any 15 consecutive days or nights;  a total number of days exceeding 40 in any 6 consecutive months. Construction Vibration Calculations 7.3.33. Construction vibration levels have been predicted at sample receptors using the algorithms included in Annex E of BS 5228-2:2009+A1:2014. Significance 7.3.34. As for construction noise, the significance of the predicted vibration levels has been determined in accordance with the guidance in DMRB LA 111, which draws heavily on BS 5228-2 and includes the following LOAELs and SOAELs, defined in terms of peak particle velocity (PPV).

Table 7-8: LOAELs and SOAELs for Construction Vibration

Time period LOAEL SOAEL

All time periods 0.3 mm/s PPV 1.0 mm/s PPV

7.3.35. Once the construction vibration levels have been predicted, they are assigned a magnitude of impact in accordance with the thresholds in Table 3.33 of DMRB LA 111, which is reproduced below for ease of reference.

Table 7-9: Vibration Level – Magnitude of Impact

Magnitude of impact Construction vibration level

Major Above or equal to 10 mm/s PPV

Moderate Above or equal to SOAEL and below 10 mm/s PPV

Minor Above or equal to LOAEL and below SOAEL

Negligible Below LOAEL

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7.3.36. The thresholds identified in Table 7-8 and Table 7-9 (0.3 mm/s, 1.0 mm/s and 10 mm/s) are the same as those set out in Table B1 from BS 5228-2. Table B1 provides the following description of the likely effect of vibration at 10 mm/s: “vibration is likely to be intolerable for any more than a very brief exposure to this level in most building environments”. Consequently, it is proposed that a more cautious 3 mm/s should be used as the threshold between moderate and major impacts. Whilst it is acknowledged that this alternative threshold is arbitrary, it is considered more realistic than 10 mm/s, which could probably only be tolerated for very brief exposures, as noted in BS 5228-2. 7.3.37. As for construction noise, minor or negligible impacts would normally be considered not significant, although this could be varied depending on acoustic context and local circumstances. Furthermore, in general, major or moderate magnitudes of impact would be considered significant effects if they occur for a duration exceeding:  10 or more days or nights in any 15 consecutive days or nights;  a total number of days exceeding 40 in any 6 consecutive months. 7.3.38. Guide values for cosmetic damage to buildings are given in BS 5228-2 (Table B.2 and associated Figure B.1, in Annex B as reproduced as Table A7-10 and Figure A7-1 in Appendix 7.3: Legislation, Policy and Guidance). These guide values are an order of magnitude higher than those for the protection of people, so these limits would only be relevant if the thresholds noted above are expected to be exceeded by a wide margin. Operational Road Traffic Noise Calculations 7.3.39. All road traffic noise predictions have been undertaken in accordance with the calculation methodology presented in the CRTN and Appendix A of DMRB LA 111 and using traffic data provided by the Design Team. 7.3.40. The Highways England guidance contained in DMRB LA 111 regarding the pivoting of modelled traffic speeds, has not been applied to the traffic data used in this assessment, as noted in the EIA Scoping Addendum. 7.3.41. The operational road traffic noise assessment considers not just the daytime period in terms of 6 LA10,18h, but also the night-time period in terms of Lnight,outside , which is equivalent to the LAeq,8h.

7.3.42. The LA10,18h has been determined directly using the supplied 18-hour (06:00-24:00) daytime traffic

flows. The Lnight has been determined using Method 3 in the TRL conversion method (Ref. 7-3). This report identifies conversion equations for two different road types: motorway and non-motorway. In this case, as none of the roads in the study area (including the Proposed Scheme) are motorways,

all calculations to determine the Lnight have utilised the non-motorway correction.

6 The terms Lnight and Lnight,outside are defined in DMRB LA 111.

Lnight = a façade noise index derived from the LA10,18hr using the TRL conversion method PR/SE/451/02

Lnight,outside = for the purpose of night-time noise assessment, the Lnight,outside is the equivalent continuous sound level LAeq,8hr for the period 23:00 to 07:00 hours assessed outside a dwelling and is free-field.

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7.3.43. The noise levels are calculated at the façade of buildings (1 m from the external façade) during the daytime and night-time. All levels are calculated at a default height of 4 m relative to the surrounding ground level. 7.3.44. Where a building is predicted to experience different changes in noise level on different façades, the result on the façade experiencing the greatest magnitude of noise change has been reported in line with the guidance contained in the DMRB LA 111. Where the greatest magnitude of change is equal on more than one façade, the façade experiencing the greatest magnitude of noise change and highest Do-Something noise level has been reported. 7.3.45. To facilitate the assessment of operational road traffic noise, a 3D digital noise model has been generated to cover the study area. Version 2019 (64 bit) of the CadnaA, PC based, noise modelling suite has been utilised and the noise model settings are described in Appendix 7.2: Noise Model (Volume III of the ESA). Magnitude of Noise Change 7.3.46. Permanent noise impacts have been assessed using guidance in DMRB LA 111, which considers the noise level changes that are predicted to arise in the short-term and the long-term with the Proposed Scheme. 7.3.47. The short-term scheme-related impacts are derived by comparing the DM scenario (without the Proposed Scheme) in the ‘opening year’ (DM2021), with the DS scenario (with the Proposed Scheme) in the same year (DS2021). 7.3.48. The long-term scheme-related impacts are derived by comparing DM scenario in the ‘opening year’ (DM2021) with the DS scenario in the future ‘design year’ (DS2036). 7.3.49. The DMRB LA 111-assessment methodology also requires a third comparison, the DM scenario in the ‘opening year’ (DM2021) with the DM scenario in the ‘design year’ (DM2036), representing the long-term change without the Proposed Scheme. 7.3.50. Table A7-4 in Appendix 7.3: Legislation, Policy and Guidance (Volume III of the ESA) summarises the classification of magnitude of noise impacts associated with short and long-term changes in road traffic noise during the daytime period, as set out in DMRB LA 111 (Tables 3.54a and 3.54b combined) and included below for ease of reference. Both adverse and beneficial changes are considered in the assessment.

Table 7-10: Magnitude of Change – Short and Long-term

Noise change, dB LA10,18h or Lnight

Magnitude of impact Short-term Long-term

Major Greater than or equal to 5.0 Greater than or equal to 10.0

Moderate 3.0 – 4.9 5.0 – 9.9

Minor 1.0 – 2.9 3.0 – 4.9

Negligible Less than 1.0 Less than 3.0

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7.3.51. The DMRB LA 111 requires the short-term and long-term noise level changes to be reported in table and/or mapping format. Changes should be reported for the daytime and night-time periods and for dwellings and other sensitive receptors. Absolute Noise Levels 7.3.52. The LOAELs and SOAELs for operational noise are defined in Table 3.49.1 in DMRB LA 111, as reproduced in Table 7-11.

Table 7-11: Operational Noise LOAELs and SOAELs for all Receptors

Time period LOAEL SOAEL

Day (06:00 – 24:00) 55 dB LA10,18h façade 68 dB LA10,18h façade

Night (00:00 – 06:00) 40 dB Lnight,outside (free-field) 55 dB Lnight,outside (free-field)

Significance 7.3.53. The process for determining whether significant effects are likely to arise due to operational road traffic noise begins with determining the magnitude of noise change in the short-term (see paragraph 7.3.52). This comparison uses the predicted daytime noise levels in the DM and the DS scenarios in the opening year (DM2021 and DS2021 respectively). This magnitude of change is compared against the scale in Table 7-12 (middle column) to provide an initial assessment of likely significant effects. 7.3.54. The starting point is that impacts of moderate magnitude or above are considered to be significant, whilst impacts of minor magnitude or below are considered to be not significant. This initial assessment is then modified, if necessary, through consideration of a combination of other factors or indicators (including absolute noise levels) that provide context to the initial assessment.

Table 7-12: Initial Assessment of Operational Noise Significance

Magnitude of impact in the short-term Short-term noise change, dB Likely significance

Major Greater than or equal to 5.0 Significant

Moderate 3.0 – 4.9 Significant

Minor 1.0 – 2.9 Not significant

Negligible Less than 1.0 Not significant

7.3.55. Where the magnitude of change in the short-term is negligible at noise sensitive receptors, it has been concluded that the noise change will not cause changes to behaviour or response to noise and as such, will not give rise to a likely significant effect.

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7.3.56. For noise sensitive receptors where the magnitude of change in the short-term is minor, moderate or major at noise sensitive buildings, other factors have been considered in the contextual assessment as follows (see DMRB LA 111 Table 3.60 - Table A7-6 in Appendix 7.3: Legislation, Policy and Guidance - for further detail):  whether the short-term change is towards the bottom or top of the short-term noise band change;  the long-term change, with the Proposed Scheme (DM2021 - DS2036) and without (DM2021 - DM2036);  the absolute noise level with reference to the LOAEL and SOAEL (see paragraph 7.3.58);  receptor specific circumstances such as:  whether the highest noise change affects a blank façade or a façade without a habitable room window;  the length of façade affected, relative to the whole building; and  whether benefits affect some façades to off-set adverse effects elsewhere (and vice versa);  whether the Proposed Scheme is likely to alter the acoustic character of the area; and  the likely perception of residents to include factors other than noise such as changes to the landscape or setting. 7.3.57. The emphasis when considering these contextual factors is whether the changes in noise would likely lead to changes in behaviour and response. 7.3.58. This assessment has been undertaken by grouping together receptors that are similarly affected, rather than considering each receptor individually. The number of properties affected by operational road traffic noise has not been considered as a factor in final evaluation of significant effects. However, if significant environmental effects are predicted for a small number of properties, this could be considered by the decision-maker when balancing overall the relative merits of the Proposed Scheme. Noise Insulation Regulations 7.3.59. Section E/2 of DMRB LA 111 requires that the environmental assessment identify properties that are likely to be eligible for insulation under the Noise Insulation Regulations (NIR) 1975, as amended. 7.3.60. A property must meet the following key conditions to qualify for insulation under the NIR:  Be within 300 m of the Proposed Scheme;  Show a relevant noise level (the noise level in the future year with the Proposed Scheme) of at

least 68 dB LA10,18h (façade);  Show a noise increase between the relevant noise level and the prevailing noise level of at least 1 dB(A); and  The contribution to the increase in the relevant noise level from the Proposed Scheme must be at least 1 dB(A). 7.3.61. The prevailing noise level is that caused by traffic using any highway immediately before works to construct or improve the highway are commenced. However, for the purposes of this assessment (given the relatively short programme for constructing the Proposed Scheme – 15 months), the prevailing noise level is taken to be equivalent to the noise level in the DM opening year scenario.

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7.3.62. For this reason, the assessment of potential eligibility under the terms of the NIR, as described in this chapter, is indicative. A full and detailed assessment will need to be undertaken and reported within six months of the opening of the Proposed Scheme, using appropriate traffic data for the assessment years specified in the NIR. Basic Noise Levels along the Wider Road Network 7.3.63. As noted in paragraph 7.3.51, the noise model has been used to determine the noise level at specific receptors within the study area. It is also necessary to consider the potential effects of the Proposed Scheme across the wider road network, in case there is a ‘knock-on’ effect beyond the main study area. 7.3.64. A BNL7 assessment has been undertaken using the traffic data provided by the Design Team and considers the same scenarios and comparisons identified above (see the section commencing at paragraph 7.3.52). It has been used to identify the potential for adverse impacts on the wider road network, beyond the main study area. 7.4 BASELINE CONDITIONS SENSITIVE RECEPTORS 7.4.1. In accordance with DMRB LA 111, examples of sensitive receptors include; dwellings, hospitals, healthcare facilities, education facilities, community facilities, END quiet areas or potential END quiet areas, international and national or statutorily designated sites, public rights of way and cultural heritage assets. 7.4.2. Existing sensitive receptors within the study area (see Figure 7-3 in Appendix 7-4: Figures (Volume III of the ESA)) have been identified using AddressBase Plus data, with receptors being allocated to one of the following categories:  Residential: • There are 889 dwellings in the defined study area, with the majority found to the east of the Proposed Scheme.  Four other sensitive receptors (including health, educational and religious uses) have been identified in the defined study area (the AddressBase Code is included in brackets): • The Bramptons Primary School, Harlestone Road, Chapel Brampton, NN6 8AW (CE03PS); • Brampton View Care Home, Brampton Valley Lane, Boughton, NN6 8GH (RI01); • Meadow View Care Home, 421 Welford Road, NN2 8PT (RI01); and • St Botolph’s Church, Harlestone Road, Church Brampton, NN6 8AU (ZW99CH). 7.4.3. There are no designated areas or scheduled monuments8 within the study area, but National Cycle Route 6 runs parallel to the Proposed Scheme approximately 200 m away on its east side and the Northamptonshire County Golf Club and the Brampton Heath Golf Centre lie adjacent to the west.

7 See footnote to paragraph 7.3.10 for a description of the BNL. 8 Boughton Bowl Barrow lies a short distance outside the main study area to the north-east.

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Noise Important Areas 7.4.4. There are no Noise Important Areas within in the study area. Planning Applications 7.4.5. It is understood that four potentially noise-sensitive residential developments in the vicinity of the Proposed Scheme have obtained planning consent and are currently in the process of being constructed. 7.4.6. Whilst most of these dwellings are yet to be completed (the exception being Buckton Fields East, which at the time of compiling this ESA was nearing completion), the road traffic associated with these developments has been included in the supplied traffic data. As there is the likelihood that at least some of the dwellings would be completed and occupied prior to the opening of the Proposed Scheme, consideration has been given to the noise impacts likely to arise as a result of the Proposed Scheme (see section commencing at paragraph 7.6.41). 7.4.7. The four developments are summarised in Table 3-1, Chapter 3: Approach to the EIA (Volume II of the ESA). EXISTING BASELINE Noise Survey Results – Unattended Long-term Measurement Locations 7.4.8. In accordance with the relevant guidance (in particular the CRTN, DMRB LA 111 and BS 5228-1),

the noise levels were measured in terms of LA10,1h and LAeq,1h, from which the LA10,18h (06:00 to 00:00

hours), LAeq,10h (08:00 to 18:00 hours) and LAeq,8h (23:00 to 07:00 hours) have been determined. The

LA90,1h and LAFmax,1h levels were also captured and are presented in Appendix 7.8: Baseline Noise

Survey Results (Volume III of the ESA) alongside the LA10,1h and LAeq,1h results.

7.4.9. The tables below present a summary of the measured sound levels in terms of the LA10,18h (Table 7-

13), LAeq,8h (Table 7-14) and LAeq,10h (Table 7-15) for each of the unattended long-term measurement locations.

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Table 7-13: Summary of Measured LA10,18h Levels, dB

Date (December LT1 – Grange LT2 – dwelling at LT3 – near Sandy LT4 – west of golf 2018) Farm near railway Grange Farm Lane course

Tuesday 4 471 452 463 474

Wednesday 5 46 44 47 49

Thursday 6 52 56 48 48

Friday 7 585 58 51 51

Saturday 8 -5 62 54 53

Sunday 9 -5 45 45 46

Monday 10 -5 48 45 46

Tuesday 11 -5 486 487 528

Notes: 1 11-hour data from 13:00 after equipment installed 2 9-hour data from 15:00 after equipment installed 3 7-hour data from 17:00 after equipment installed 4 8-hour data from 16:00 after equipment installed 5 The equipment failed after 14:00 on Friday due to low battery charge 6 9-hour data until 15:00 before measurement stopped 7 7-hour data until 13:00 before measurement stopped 8 6-hour data until 12:00 before measurement stopped

Table 7-14: Summary of Measured LAeq,8h Levels, dB

Date (December LT1 – Grange LT2 – dwelling at LT3 – near Sandy LT4 – west of golf 2018) Farm near railway Grange Farm Lane course

Tuesday 4 69 52 46 44

Wednesday 5 71 54 46 39

Thursday 6 69 56 48 47

Friday 7 -1 61 51 51

Saturday 8 -1 58 49 49

Sunday 9 -1 48 38 37

Monday 10 -1 50 43 42

Note: 1 The equipment failed after 14:00 on Friday due to low battery charge

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Table 7-15: Summary of Measured LAeq,10h Levels, dB

Date (December LT1 – Grange LT2 – dwelling at LT3 – near Sandy LT4 – west of golf 2018) Farm near railway Grange Farm Lane course

Tuesday 4 681 532 443 484

Wednesday 5 68 52 48 50

Thursday 6 67 58 48 48

Friday 7 665 56 50 51

Saturday 8 -5 61 51 52

Sunday 9 -5 50 45 46

Monday 10 -5 55 48 48

Tuesday 11 -5 526 487 528

Notes: 1 5-hour data from 13:00 after equipment installed 2 3-hour data from 15:00 after equipment installed 3 1-hour data from 17:00 after equipment installed 4 2-hour data from 16:00 after equipment installed 5 The equipment failed after 14:00 on Friday due to low battery charge. 6 7-hour data until 15:00 before measurement stopped 7 5-hour data until 13:00 before measurement stopped 8 4-hour data until 12:00 before measurement stopped

7.4.10. It is typical for quieter noise levels to occur during weekends when roads are less busy, and some businesses are closed. However, elevated levels in all indices can be observed during Saturday 8 December, which may be linked to breezier conditions on that day (see paragraph 7.3.25) 7.4.11. It can be seen that night-time noise levels at both measurement positions near Grange Farm are high compared to those measured at other locations. Although daytime levels would ordinarily be higher than those during the night, it was noted that the night-time noise environment at both LT1 and LT2 is influenced by freight train movements along the Rugby to Milton Keynes railway line.

7.4.12. Some inconsistencies in LA10,18h level can be also observed at LT2 near Grange Farm. However, this position is influenced by local activities at the farm and so it would be reasonable to see greater variation in noise levels at this location. Noise Survey Results – Attended Short-term Measurement Locations 7.4.13. Where unattended long-term measurements were unobtainable due to lack of secure locations, the shortened measurement procedure was used in accordance with CRTN. Noise levels, in terms of

the LA10, were measured over three consecutive hours between 10:00 and 17:00. The LAeq, LAFmax

and LA90 indices were also captured. A summary of the short-term measurement results is presented in Table 7-16 and Table 7-17.

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Table 7-16: Summary of Measurement Results at ST1 - Kingsthorpe North Meadows, dB

Period start LAeq,1h LA90,1h LA10,1h LAFmax,1h

07/12/2018 12:20 46 41 48 74

07/12/2018 13:20 49 41 51 73

07/12/2018 14:20 48 42 51 68

Arithmetic average n/a 50 n/a

Table 7-17: Summary of Measurement Results at ST2 - Northampton Road, dB

Period start LAeq,1h LA90,1h LA10,1h LAFmax,1h

06/12/2018 13:57 66 55 70 84

06/12/2018 14:57 67 57 70 89

06/12/2018 15:57 67 58 71 86

Arithmetic average n/a 70 n/a

7.4.14. The noise environment at ST1 at Kingsthorpe North Meadows was dominated by a combination of noise from pedestrians, cyclists and dogwalkers. Considering the proximity of the measurement location to these noise sources, some variation in noise levels between hourly periods may be

expected. The LAFmax at ST2 is consistent between hourly periods because road traffic was the

dominant source. The measured hourly LAeq, LA10 and LA90 levels from both short-term measurement positions do not show any abnormal variations.

7.4.15. From the arithmetic average LA10,3h, the estimated LA10,18h, in line with the methodology set out in the CRTN, is 49 dB at ST1 in Kingsthorpe North Meadows and 69 dB at ST2 on Northampton Road. Opening Year (2021), without the Proposed Scheme 7.4.16. The operational road traffic noise assessment relies primarily on an appraisal of predicted road traffic noise levels. In order to validate the predicted noise levels from the 3D noise model, the results from the noise model containing 2018 baseline year (BY2018) traffic data have been

compared with the minimum LA10,18h measurement results recorded for Locations LT1 to LT4, as presented in Table 7-13.

7.4.17. It can be seen from Table 7-13 that the minimum measured LA10,18h noise levels range between 44 dB (at LT2) and 46 dB (at LT1 and LT4), a range of 2 dB which is considered consistent. 7.4.18. The noise model was run with traffic data for the BY2018 scenario and generated a noise level of 39.2 dB at LT2. This level is approximately 5 dB below the measured minimum and so consideration was given to adding a ‘noise floor’ to avoid under-predicting the modelled results in areas remote

from existing roads. Through log subtraction, it was determined that a ‘noise floor’ of 42.7 dB LA10,18h should be added universally to the modelled results. Having made this adjustment, the comparison of measured and predicted noise levels was undertaken, as presented in Table 7-18.

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Table 7-18: Comparison of Predicted Road Traffic Noise Levels in BY2018 with Levels Measured at Locations LT1 to LT4 in 2018

Noise level, LA10,18h (dB) Difference between measured and Minimum measured Predicted level in predicted noise levels Measurement location level, 2018 baseline year, 2018 (dB)

LT1 46.2 44.7 -1.5

LT2 44.3 44.3 ±0.0

LT3 44.9 51.0 +6.1

LT4 45.6 45.7 +0.1

7.4.19. The measured LA10,18h results at positions LT2 and LT4 are within 0.1 dB of the predicted LA10,18h BY2018 results whilst the difference at LT1 is 1.5 dB. The difference at LT3 is 6.1 dB; however, it

must be remembered that the comparison is against the minimum measured LA10,18h. The measured levels at LT3 actually range between 45 dB and 54 dB, so the predicted level falls within the

measured range (there were two days where the measured LA10,18h was above the predicted level of 51 dB). FUTURE BASELINE Future Year (2036), without the Proposed Scheme 7.4.20. In line with DMRB LA 111, consideration has been given to the change in noise levels that will arise at identified receptors, in the long-term, without the Proposed Scheme (i.e. DM2036 compared to DM2021). 7.4.21. Table 7-19 presents the number of receptors within the study area subject to different noise level changes in the long-term without the Proposed Scheme. Figure 7-5 in Appendix 7.4: Figures (Volume III of the ESA) presents a long-term noise change contour map showing the areas where noise levels increase and decrease without the Proposed Scheme.

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Table 7-19: Long-term Noise Changes (2021-2036) without the Proposed Scheme

Daytime Night-time

Magnitude Number of Number of Change in noise level of impact Number of other Number of other dwellings sensitive dwellings sensitive receptors receptors *

Increase 0.1 – 2.9 dB Negligible 889 4 889 2 in noise level 3.0 – 4.9 dB Minor - - - - LA10,18h / Lnight 5.0 – 9.9 dB Moderate - - - -

≥ 10 dB Major - - - -

No change 0 dB No change - - - -

Decrease 0.1 – 2.9 dB Negligible - - - - in noise level 3.0 – 4.9 dB Minor - - - - LA10,18h / Lnight 5.0 – 9.9 dB Moderate - - - -

≥ 10 dB Major - - - -

Note: * There are two fewer entries in this column compared to the equivalent daytime column. This is because it is assumed that The Bramptons Primary School and St Botolph’s Church would generally not be in use during the night-time period

7.4.22. Table 7-19 shows that the all dwellings and other sensitive receptors are predicted to experience an impact of negligible magnitude (not significant) in DM2036 during the day and night. 7.5 EFFECTS ARISING DURING CONSTRUCTION PRIMARY MITIGATION MEASURES 7.5.1. No avoidance or primary mitigation measures have been identified in relation to construction phase noise and vibration. ASSESSMENT OF IMPACTS AND EFFECTS 7.5.2. The following elements are considered to have the potential to give rise to likely significant effects during the construction of the Proposed Scheme and have therefore been considered within the ESA:  Noise from on-site construction activities; and  Vibration from on-site construction activities.

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Temporary Noise Effects during Construction 7.5.3. Typical construction phase noise levels have been predicted for key construction activities at two receptors that lie within the 300 m study area:  Boughton Crossing House, Welford Road, Chapel Brampton, NN6 8AB (c55 m north of the centre of the Brampton Lane Roundabout); and  Grange Farm, Mill Lane, Northampton, NN5 7PZ (c210 m west of the centre line of the Main Carriageway). 7.5.4. Any sensitive receptors located further away than those identified above should experience lower levels of construction noise and vibration (and by association impacts and effects). 7.5.5. Compared to dwellings, PRoW and the golf courses are considered less sensitive to noise and vibration arising from construction activities. This is due to their occasional and transient use, allied with the temporary and variable nature of any noise and vibration generated during the construction phase. Furthermore, at any point in time, the extent of the area adversely impacted by construction phase noise and vibration is expected to be relatively small compared to the overall area. Consequently, PRoW and the golf courses have not been included in the construction noise and vibration assessment. 7.5.6. The 3D noise model prepared for the operational road traffic noise assessment has also been utilised for the construction noise assessment, but with the BS 5228-1 prediction method (rather than the CRTN) selected. 7.5.7. A high-level schedule of construction plant has been provided by the Design Team. The plant has been taken to be either ‘static’ or ‘mobile’. Static plant has been assumed to operate at the nearest point to each receptor, whilst mobile plant (which are associated with earth moving activities, drainage and road surfacing) have been assumed to operate along the nearest section of the Proposed Scheme alignment. Hence, in this regard, predictions can be taken to represent a cautiously pessimistic assessment. 7.5.8. Table 7-20 to Table 7-24 set out the plant items, quantities and assumed utilisation rates used in the prediction of noise levels during each of the key activities.

Table 7-20: Assumed Plant Details – Earth Moving Activities

Sound pressure Plant item Number level, LPA at 10m Data source On-time

25t-40t articulated dump truck ^ 2 81 dB BS 5228-1, C4/1 100%

10t-40t tracked excavator 4 79 dB BS 5228-1, C2/14 100%

D5/D6 tracked dozer 2 81 dB BS 5228-1, C2/12 100%

Wheeled grader ^ 1 86 dB BS 5228-1, C6/31 100%

17t vibratory twin drum roller ^ 1 79 dB BS 5228-1, C2/37 100%

Note: ^ mobile plant

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Table 7-21: Assumed Plant Details – Drainage

Sound pressure Plant item Number level, LPA at 10m Data source On-time

5t-30t excavators 1 75 dB BS 5228-1, C2/16 100%

8t dumper ^ 1 76 dB BS 5228-1, C4/4 100%

4" diesel pump 1 65 dB BS 5228-1, C2/45 100%

2t Bomag roller ^ 1 73 dB BS 5228-1, C2/40 100%

Note: ^ mobile plant

Table 7-22: Assumed Plant Details – Piling

Sound pressure Plant item Number level, LPA at 10m Data source On-time

Continuous flight auger 1 83 dB BS 5228-1, C3/14 50%

Mobile crane 1 70 dB BS 5228-1, C3/30 50%

Table 7-23: Assumed Plant Details – Construction of Structure

Sound pressure Plant item Number level, LPA at 10m Data source On-time

40t-800t mobile crawler crane 1 71 dB BS 5228-1, C4/50 20%

20m-66m concrete pumps 1 78 dB BS 5228-1, C4/32 5%

4" diesel pump for de-watering 1 65 dB BS 5228-1, C2/45 20%

2kVa generators 1 65 dB BS 5228-1, C4/83 100%

Telescopic forklift 1 71 dB BS 5228-1, C2/35 100%

Hand tools (various) 5 78 dB BS 5228-1, C4/33 100%

Table 7-24: Assumed Plant Details – Road Surfacing

Sound pressure Plant item Number level, LPA at 10m Data source On-time

Road paver and tipper lorry 1 75 dB BS 5228-1, C5/33 50%

Road planer 1 82 dB BS 5228-1, C5/7 20%

2t-10t tandem vibratory rollers ^ 1 84 dB BS 5228-1, C5/24 50%

Note: ^ mobile plant

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7.5.9. For all scenarios, the predicted façade noise levels are based on the following assumptions:  Noise propagation is hemispherical;  The intervening ground between the construction noise source and the relevant noise sensitive property is predominantly absorptive in the acoustic sense with an absorption coefficient of 0.75;  There is no attenuation from atmospheric absorption;  The predicted noise levels are those under neutral weather conditions;  Source levels use frequency data from BS 5228-1, but calculations have been undertaken at 500 Hz;  All plant has been set with a source height of 1.5 m; and  Speed of mobile plant – dump trucks and dumper 10 kph, all other plant items 5 kph. 7.5.10. The outline construction programme, as presented in Table 2-3, Chapter 2: Changes to the Description of the Proposed Scheme (Volume II of the ESA), stretches from Q3 2020 to Q3 2021. Based on the construction programme it can be expected that many of the activities will have to over-lap with many of the plant items being utilised simultaneously, albeit in different geographical locations. Consequently, it is assumed that earth moving activities, drainage, piling and construction of structures could all occur simultaneously. 7.5.11. Therefore, based on the information presented above, and the procedures given in BS 5228-1, noise levels have been calculated for the following scenarios;  Daytime – all plant, except for road surfacing (which is assumed to occur towards the end of the construction programme and is assessed separately – see paragraph 7.5.19); and  Night-time – structures work at the new railway overbridge (because of the need, for safety reasons, to work during night-time track possessions).

7.5.12. The predictions are in terms of LAeq,T at the façade, where ‘T’ equals 10 hours during weekdays (08:00-18:00) or 5 hours on Saturday morning (08:00-13:00) and 8 hours during the night (23:00- 07:00). 7.5.13. For the sample receptors, it is necessary in the first instance to determine into which BS 5228-1 ABC category they fall. The process is presented in Table 7-25 (following). All noise levels have 9 been determined using the noise model. Daytime levels are in terms of LAeq,12h at the ground floor

façade, whilst night-time levels are in terms of LAeq,8h at the first-floor façade. For each receptor, the assessment has been made at the façade facing the works (as noted in Table 7-25). The rounding and categorisation process are as determined in BS 5228-1 (see Table 7-5).

9 The LAeq,12h level has been determined using Method 3 in the TRL conversion method (Ref. 7-3).The predicted LAeq,12h is assumed to be equivalent to the LAeq,10h for the purpose of determining into which BS 5228-1 ABC category each receptor falls.

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Table 7-25: Determination of ABC Category at Each Receptor

Predicted ambient Rounded to the ABC threshold, dB noise level LAeq,T (dB) nearest 5 dB (ABC category)

Receptor Day Night Day Night Day Night

Boughton Crossing House1 69 61 70 60 75 (Cat C) 61 (Cat C)

Grange Farm2 47 37 45 35 65 (Cat A) 45 (Cat A)

Notes: 1 Boughton Crossing House, south facing façade 2 Grange Farm, east facing façade It has been assumed that the LAeq,12h level (applicable to weekdays) is equivalent to the LAeq,5h level for Saturdays.

7.5.14. Grange Farm, which is remote from dominant road traffic sources, is defined as category A during the day and night. Boughton Crossing House, located just a few metres from Welford Road, is defined as category C during the day and night. 7.5.15. The predicted construction noise levels are presented in Table 7-26, together with the magnitude of impact based on the criteria derived from Table 7-6 and Table 7-7, in line with the relevant ABC category. The figures in brackets are the derived ABC threshold from Table 7-25.

Table 7-26: Predicted Construction Noise Levels

Daytime Night-time

Predicted Magnitude of Predicted Magnitude of Receptor LAeq,10h (dB) impact LAeq,8h (dB) impact

Boughton Crossing House 77 (75) Moderate 34* (61) Negligible

Grange Farm 58 (65) Negligible 51* (45) Major

Note: * Although Boughton Crossing House is much closer to the Proposed Scheme than Grange Farm, it is more remote from the new railway overbridge where the night works are assumed to occur. Hence, the night-time predicted noise level at Boughton Crossing House is notably lower than it is at Grange Farm.

7.5.16. At Boughton Crossing House, an impact of moderate magnitude is anticipated during the day, which is considered potentially significant. However, it must be noted that the predictions here are likely to be an over-estimate, as all plant for all activities (except road surfacing, which occurs towards the end of the construction programme) would be occurring simultaneously at the closest location to the property. In reality, it is likely that plant and activities would be more spread out, both in terms of activity and the geographical location of plant within that activity. 7.5.17. As the predicted daytime levels at this receptor are only 2 dB above the relevant SOAEL (75 dB

LAeq,T), there must be some uncertainty whether in reality the works in this location would exceed the SOAEL for the duration(s) set out in paragraph 7.3.38 and therefore whether these moderate impacts would actually be likely to give rise to significant adverse effects. Nevertheless, consideration is given to secondary mitigation measures in the following section.

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7.5.18. At Grange Farm, a major adverse impact is predicted at night during the construction of the bridge over the railway line. However, on further scrutiny this level is predicted at the eastern end of the farm building, which is believed not to contain habitable rooms, these being located more centrally. Noise levels affecting the more central part of the building are more than 10 dB below those at the eastern end of the building (approximately 39 dB) due mainly to screening provided by other farm buildings. The predicted noise levels affecting the more central part of the building would be classified as an impact of negligible magnitude and not significant. 7.5.19. There is also a need to consider road surfacing, which is assumed to occur during the daytime. As this generates lower levels than the other works it is appropriate to consider the impact at Boughton Crossing House only as Grange Farm lies further from the works. The surfacing works at this

property generate a façade level of 72 dB LAeq,10h on the south facing ground floor façade. This translates to an impact of minor magnitude, which is considered not significant. Summary 7.5.20. The predictions generally indicate that construction noise would result in effects described as not significant. However, if the works at Boughton Crossing House generate daytime construction noise levels above the SOAEL for the duration(s) set out in paragraph 7.3.38, this indicates a potential for adverse effects, prior to the implementation of mitigation measures, that could be described as direct, temporary, short-term and significant. Therefore, mitigation measures to further minimise the effects of noise during the construction phase are discussed below (see section commencing at paragraph 7.5.34). Temporary Vibration Effects during Construction 7.5.21. The main source of construction generated ground-borne vibration within the 100 m study area is anticipated to be the use of vibratory compactors during earthworks. Perceptible levels of vibration can also be experienced during the use of vibratory rollers during the final stages of road surfacing. To estimate the levels of vibration for vibratory compactors, the prediction method detailed in BS 5228-2 has been used. Two different vibratory compactors have been considered; one with a twin drum roller and the other with a single drum roller, with each having a high and low amplitude setting:  A twin drum roller with a 1.7 m drum width and a vibration amplitude of 0.4 mm and 0.9 mm, operating at a low and high setting respectively (e.g. a Bomag BW161AD).  A single drum roller with a 2.1 m drum width and a vibration amplitude of 1.1 mm and 2.1 mm, operating at a low and high setting respectively (e.g. a Bomag BW213D-5). 7.5.22. The predictions have been based in steady state operation, and on the assumption that there is a 33% probability of the predicted PPV vibration level being exceeded (and a 67% probability that it is not), as set out in BS 5228-2. 7.5.23. ‘Steady state’ and ‘start-up and run-down’ conditions have been considered for each compactor and for both high and low amplitude settings. This has been done for a single property – Boughton Crossing House – as this is the only receptor within the 100 m study area. 7.5.24. The predicted vibration levels are presented in Table 7-27 and Table 7-28, together with the relevant magnitude of impact based on the scale derived from Table 7-8 and Table 7-9. The predicted vibration levels are in terms of the peak particle velocity vibration, in units of mm/s.

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Table 7-27: Predicted Vibration Levels During Use of a Twin Drum Vibratory Compactor

Steady state PPV Start-up and run- vibration level Magnitude of down PPV vibration Magnitude of Amplitude setting (mm/s) impact level (mm/s) impact

Low (0.4 mm) 0.2 Negligible 0.3 Minor

High (0.9 mm) 0.8 Minor 1.2 Moderate

Table 7-28: Predicted Vibration Levels During Use of a Single Drum Vibratory Compactor

Steady state PPV Start-up and run- vibration level Magnitude of down PPV vibration Magnitude of Amplitude setting (mm/s) impact level (mm/s) impact

Low (1.1 mm) 0.7 Minor 1.1 Moderate

High (2.1 mm) * 1.9 Moderate 3.0 Moderate ^

Note: * The method is strictly valid up to an amplitude of 1.72 mm; so, a heightened level of uncertainty would be applicable to this result ^ A PPV vibration level of 3 mm/s is the threshold between moderate and major impacts and in line with paragraph 7.3.42 and Table 7-9 this would normally be described as a major impact. However, in this case, the predicted level rounds up from below 3 mm/s and so a moderate impact is described.

7.5.25. It can be seen that for use of the twin drum compactor, the magnitude of impact for all operating conditions is minor or negligible (not significant) with the exception of the start-up and run-down on high amplitude setting where the magnitude of impact would be moderate (potentially significant). 7.5.26. For the single drum compactor operating under steady state conditions on a low amplitude setting, the resulting vibration would amount to a minor magnitude of impact (not significant). Other operations would generate impacts of moderate magnitude (potentially significant). 7.5.27. With all predicted levels being no greater than 3 mm/s, there is minimal likelihood of building damage (see paragraph 7.3.44). Summary 7.5.28. The assessment presented above must be viewed as indicative. The actual levels of vibration likely to be generated will depend on the specific item of plant and this won’t be known until the contractor has been appointed and an inventory of plant has been drawn-up. 7.5.29. It can be seen that where the magnitude of impact is negligible or minor, adverse effects are most likely to be not significant. However, in some circumstances (with certain plant settings and when plant is working in close proximity to sensitive buildings), an impact of moderate magnitude is predicted. As mentioned above with respect to noise, there is some uncertainty whether the works at Boughton Crossing House would exceed the vibration SOAEL for the duration(s) set out in paragraph 7.3.43 and therefore whether these moderate impacts would actually be likely to give rise to significant adverse effects. Nevertheless, there is the potential for adverse effects, prior to the implementation of mitigation measures, that could be described as direct, temporary, short-term and significant.

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7.5.30. Consequently, care will be required to manage the works to mitigate and minimise adverse effects and to this end specific measures are considered below (commencing at paragraph 7.5.38). Permanent Effects of Construction Noise and Vibration 7.5.31. There are no permanent effects in terms of construction noise and vibration. MITIGATION MEASURES 7.5.32. The adoption of Best Practicable Means (BPM), as defined in the Control of Pollution Act 1974, will be a fundamental mitigation measure. BPM will comprise a series of noise and vibration control measures, which will be incorporated within a Construction Environmental Management Plan (CEMP). Compliance with CEMP, which will be prepared in association with the relevant local authorities, will result in adverse impacts from construction noise and vibration being minimised at nearby sensitive receptors. 7.5.33. The most relevant measures with respect to noise and vibration are set out below and will be incorporated within the Outline CEMP (Appendix 3.1: Outline CEMP (Volume III of the ES)):  Any generators or other similar equipment brought on to site should be silenced or sound reduced models fitted with acoustic enclosures;  All pneumatic tools should be fitted with silencers or mufflers;  Deliveries should be programmed to arrive during daytime hours only. Care should be taken when unloading vehicles to minimise noise. Delivery vehicles should be routed so as to minimise disturbance to local residents. Delivery vehicles should be prohibited from waiting within or in the vicinity of the site with their engines running;  All plant items should be properly maintained and operated according to manufacturers’ recommendations and in such a manner as to avoid causing excessive noise and vibration;  All plant should be sited so that noise and vibration impacts are minimised; and  A neighbourly approach should be adopted throughout the construction phase (for example, adhering to the construction site working hours, keeping stakeholders informed, ensuring that best practicable means are adopted at all times) so that impacts are minimised. Temporary Construction Noise 7.5.34. It was identified in paragraph 7.5.20 that there is the potential for a significant adverse effect at Boughton Crossing House, prior to the implementation of mitigation measures. Further scrutiny of the predicted noise level, and in particular the breakdown showing the contribution of each individual

plant item to the predicted overall noise level of 76 dB LAeq,T at Boughton Crossing House, reveals that the most influential plant items are the tracked excavator (4no.) and tracked dozer (2no.) connected with earth moving activities. 7.5.35. The assumption is that these six items are located at the closest approach to Boughton Crossing House at the eastern end of the Causeway and operating 100% of the time during the day. Although it seems unlikely that all six items of plant would be operational at the closest approach to this (or any) property for the whole day, consideration has been given to the benefit that might arise from introducing a noise barrier to reduce noise from construction plant.

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7.5.36. BS 5228-1 notes the following with regard to the likely performance of a noise barrier or screen: “…as a working approximation, if there is a barrier or other topographic feature between the source and the receiving position, assume an approximate attenuation of 5 dB when the top of the plant is just visible to the receiver over the noise barrier, and of 10 dB when the noise screen completely hides the sources from the receiver” 7.5.37. For illustrative purposes, a -5 dB correction for a partial barrier has been applied to these six items of plant (a 2.4 m high solid site hoarding located at the site boundary should provide this magnitude of noise reduction). With this mitigation included, the noise predictions have been repeated and the overall noise level reduces by around 2 dB to just below 75 dB. Temporary Construction Vibration 7.5.38. The mitigation measures adopted to control noise levels during the construction phase should also help keep vibration levels to a minimum. In particular, it is assumed that BPM outlined in paragraph 7.5.32 will also be adopted, whilst all plant items will be properly maintained and operated according to manufacturers’ recommendations in such a manner as to avoid causing excessive vibration. 7.5.39. Plant with variable amplitude settings should be employed, with the lowest setting being used where conditions demand. Another measure might be to restrict or limit certain works (specifically start-up and run-down) from being undertaken close to sensitive receptors. The table below identifies the restriction in terms of separation distance for specific operations and amplitude settings.

Table 7-29: Distances at which the Use of Vibratory Compactors may need to be Restricted

Twin drum Single drum

Steady state Start-up and run- Steady state Start-up and run- Amplitude setting operation down operation operation down operation

Low No restriction* No restriction* No restriction* 38 m

High No restriction* 41 m 56 m 84 m

Note: * No restriction on the basis that vibratory compactors would need to work no closer than 35 m from any sensitive receptor. This table and its contents are for illustrative purposes only, as it is not known at this stage the exact type of plant that will be employed on the site.

SUMMARY OF LIKELY RESIDUAL SIGNIFICANT EFFECTS Temporary Construction Noise 7.5.40. With an adverse impact of minor magnitude predicted for the most affected receptor after implementation of mitigation measures (see section commencing at paragraph 7.5.34), residual adverse effects would be direct, temporary, short-term and not significant. Temporary Construction Vibration 7.5.41. In the section commencing at paragraph 7.5.38 consideration has been given to a number of mitigation measures that might be employed to reduce vibration levels.

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7.5.42. By preventing the occurrence of specific activities (such as start-up or run-down) in close proximity to sensitive receptors and/or adopting certain settings (for example, low amplitude rather than high), then adverse impacts of minor magnitude at worst would prevail at the most affected receptor and residual adverse effects would be direct, temporary, short-term and not significant. CUMULATIVE ASSESSMENT Cumulative Effects 7.5.43. No intra-project cumulative effects are anticipated that involve noise and vibration and the receptors considered in this chapter, but see Chapter 7: Biodiversity (Volume II of the ES) for effects of noise and vibration on fauna and Chapter 14: People and Communities (Volume II of the ES) for effects of noise and vibration on human health. Combination Effects 7.5.44. The outline construction programme for the Proposed Scheme has the main construction works covering a 15-month period from the start of Q3 2020 to the end of Q3 2021. It is only during this period that cumulative construction phase noise and vibration impacts could arise. 7.5.45. It is also the case that for any receptor to experience cumulative effects, it would need to lie in proximity to both the Proposed Scheme and at least one of the other cumulative developments for noise and vibration levels to combine in any meaningful way. The developments that during their construction could contribute to cumulative construction phase effects are listed in paragraph 7.3.18. 7.5.46. The Proposed Scheme necessarily will involve some out-of-hours working (in relation to the construction of the railway overbridge). However, it is assumed that the activities associated with the construction of the residential-led developments would occur during typical construction site working hours when people are generally more tolerant towards noise and vibration and appropriate criteria would be higher. The construction phase assessment undertaken for the Proposed Scheme (as presented earlier in this section) identifies that during the day, works have to be relatively close to receptors (typically within 200 m) to result in significant effects. 7.5.47. Cumulative vibration is unlikely to result in significant effects where either the Proposed Scheme or the cumulative development (or both) lie more than 100 m from any receptor and that is the case for receptors considered in this chapter. Both of the receptors are considered in turn in terms of the likelihood that simultaneous construction activities would combine to generate a noise effect that is notably larger than that from the Proposed Scheme in isolation. Boughton Crossing House 7.5.48. Pre-mitigation, this property has a predicted impact from the Proposed Scheme of moderate magnitude, which is considered potentially significant, with construction works occasionally occurring within 50 m of the receptor. 7.5.49. The works associated with the Buckton Fields development would be at least 110 m away. The ES submitted in support of the Buckton Fields planning application anticipates moderate/major impacts, based on a worst-case approach to the assessment, not just at the closest receptors (those residential areas immediately to the south) but also at more distant receptors to the north, north-east and east. No mention is made of receptors to the west or north-west, including Boughton Crossing House or the nearby Windhover Public House (PH).

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7.5.50. The Buckton Fields ES does go on to provide context to the conclusions pointing out that the impacts are based on a worst-case scenario with plant located at the closest approach. Based on the application of appropriate management and control measures, the ES concludes “it is considered unlikely that significant long-term moderate to major impacts will arise during the construction phase at a large number of properties due to the transient nature of construction operations”. 7.5.51. Notwithstanding the above and that the minimum distance between Boughton Crossing House and the Buckton Fields development would be greater than 100 m, the potential for construction noise from the Buckton Fields development to combine with that generated by the Proposed Scheme to cause a significant effect cannot be discounted at this stage, especially given that post mitigation impacts of minor magnitude are predicted from the Proposed Scheme in isolation. Grange Farm 7.5.52. The Dallington Grange development lies to the south of the Proposed Scheme, with the only property likely to be significantly affected by this development and the Proposed Scheme being Grange Farm itself. 7.5.53. An addendum ES submitted in 2018 for the Dallington Grange development identifies a 10-year construction period running from 2021 to 2031, so it is possible that the construction works for this development and the Proposed Scheme would not overlap. 7.5.54. Furthermore, it is understood that Grange Farm is identified for redevelopment (as a café/restaurant/public house or hotel) as part of the Dallington Grange development and, therefore, it is likely that this receptor will be removed at some point in the future 7.5.55. Overall, it seems that there would be a low probability of significant cumulative effects from the Dallington Grange development in combination with the Proposed Scheme. Summary 7.5.56. The assessment presented in this chapter in relation to the construction of the Proposed Scheme indicates that with appropriate mitigation measures in place, the residual noise and vibration effects would be direct, temporary, short-term adverse and not significant. 7.5.57. The prospect of construction activities associated with other developments coinciding to generate cumulative effects that are greater than those reported for the Proposed Scheme in isolation remains low. The potential for construction noise from cumulative developments to combine to generate higher noise levels cannot be discounted at this stage, especially at Boughton Crossing House. Whether the combined noise levels translate into a significant effect that is greater than those reported above is uncertain.

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7.6 EFFECTS ARISING FROM OPERATION PRIMARY MITIGATION MEASURES 7.6.1. During the iterative design of the Proposed Scheme, due consideration has been given to measures that can be incorporated into the engineering design to minimise potential impacts. Each of these considerations is described below:  Horizontal alignment (moving a route away from sensitive receptors). The Main Carriageway adopts the most westerly alignment that it can, maximising the separation distance between the Proposed Scheme and residential areas to the east (those areas accessed off Welford Road).  Vertical alignment (keeping a route low within the natural topography to exploit any natural screening). The Proposed Scheme has been kept as low as possible within the natural topography, but the requirement for the Proposed Scheme to cross the Milton Keynes to Rugby railway line and the presence of the flood plain means that the Main Carriageway will have a raised profile, running along an embankment of varying height along its entire length.  Low noise surface (effective at reducing noise in the mid to high frequencies where tyre noise dominates, which typically is where speeds are in excess of 75 kph, or around 47 mph). The supplied traffic data indicate speeds of less than 75 kph in all scenarios. A thin surface course system will be laid on the Proposed Scheme and whilst such a surface might have some noise reducing qualities, none has been claimed due to the supplied traffic speed.  Speed and volume restrictions (all else remaining the same, lowering traffic speeds and volumes will serve to reduce road noise at source). The Proposed Scheme is for a single (rather than dual) carriageway with a proposed speed limit of 50 mph (rather than the national speed limit). A single carriageway will serve to limit the volume of traffic that can be accommodated (compared to a dual carriageway) and the imposition of a 50 mph speed limit (rather than 60 mph) will serve to reduce speeds. Both of these design considerations should result in reduced noise at source. ASSESSMENT OF IMPACTS AND EFFECTS 7.6.2. Detailed predictions have been carried out for a total of 889 residential receptors within the study area, together with four other sensitive receptors, comprising two nursing homes, a school and a church, which are considered in a separate section commencing at paragraph 7.6.41. 7.6.3. All noise levels and noise changes are presented for both the short-term (comparing DM2021 and DS2021) and the long-term (comparing DM2021 and DS2036). Short-term Noise Level Changes (2021) 7.6.4. Table 7-30 (following) shows the predicted short-term change in noise level for all modelled receptors within the study area, sorted into the noise change bands following DMRB LA 111 magnitude of impact categories. Figure 7-6 in Appendix 7.4: Figures (Volume III of the ESA) presents a short-term noise change contour map showing the areas where noise levels increase and decrease with the Proposed Scheme in the short-term. 7.6.5. The magnitude of short-term noise impacts as a result of the Proposed Scheme range from major adverse to major beneficial. Broadly the impacts during the day and night are similar.

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Table 7-30: Short-term Noise Changes with the Proposed Scheme

Daytime Night-time

Number of Number of other other Magnitude Number of sensitive Number of sensitive Change in noise level of impact dwellings receptors dwellings receptors *

Increase 0.1 – 0.9 dB Negligible 8 - 6 - in noise level 1.0 – 2.9 dB Minor 430 - 442 - LA10,18h / Lnight 3.0 – 4.9 dB Moderate 141 1 134 1

≥ 5 dB Major 49 1 46 1

No change 0 dB No change - - - -

Decrease 0.1 – 0.9 dB Negligible 4 - 7 - in noise level 1.0 – 2.9 dB Minor 73 - 95 - LA10,18h / Lnight 3.0 – 4.9 dB Moderate 137 1 138 -

≥ 5 dB Major 47 1 21 -

Note: * There are two fewer entries in this column compared to the equivalent daytime column. This is because it is assumed that The Bramptons Primary School and St Botolph’s Church would generally not be in use during the night-time period

Short-term Noise Increases 7.6.6. It can be seen from Table 7-30 that 141 dwellings are predicted to experience an adverse impact of moderate magnitude in the short-term during the day (134 at night) as a result of the Proposed Scheme, with a further 49 dwellings predicted to experience an adverse impact of major magnitude during the day (46 at night). Of the other (non-residential) sensitive receptors, one is predicted to experience an adverse impact of moderate magnitude (Brampton View Care Home) and one is predicted to experience an adverse impact of major magnitude (Meadow View Care Home). This is the case for both daytime and night-time periods (see also section commencing at paragraph 7.6.41). 7.6.7. Table 7-31 provides a breakdown of the dwellings predicted to experience an adverse impact of moderate and major magnitude in the short-term, according to postcode area and the absolute noise level in DS2021. Daytime and night-time levels have been considered as required by DMRB LA 111. The table refers to a number of different absolute threshold levels, which are those presented in Table 7-11). In summary these thresholds, which are those adopted by Highways England, are:

 Day: LOAEL 55 dB and SOAEL 68 dB, in terms of LA10,18h façade; and

 Night: LOAEL 40 dB and SOAEL 55 dB, in terms of Lnight,outside free-field.

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7.6.8. Notwithstanding the magnitude of the predicted change in noise, overall noise levels will be low for many receptors. Those receptors with a noise level at or below the adopted LOAEL in DS2021 have been discarded on the basis that the perception of road traffic noise, whilst noticeable, would not be intrusive and there should be no change to quality of life. Consequently, the following residential receptors (124 in number) are retained for further consideration.

Table 7-31: Location and Number of Residential Receptors Subject to an Adverse Impact of Moderate and Major Magnitude in the Short-term

Short-term, daytime Short-term, night-time

Postcode Location Number Magnitude DS2021 Magnitude DS2021

Buckton Fields East (37 receptors)

NN2 8ES Home Farm Drive 2 Moderate >SOAEL Moderate >SOAEL

7 Moderate >LOAEL Moderate >LOAEL

1 Moderate >LOAEL Minor >LOAEL

NN2 8BX Bochetone 2 Moderate >SOAEL Moderate >SOAEL

1 Moderate >SOAEL Moderate >LOAEL

6 Moderate >LOAEL Moderate >LOAEL

1 Moderate >LOAEL Minor >LOAEL

NN2 8EZ Hanging Barrows 1 Moderate >LOAEL Minor >LOAEL

NN2 8FA Tiggyhole 1 Moderate >SOAEL Moderate >SOAEL

1 Moderate >SOAEL Moderate >LOAEL

7 Moderate >LOAEL Moderate >LOAEL

NN2 8FB Far Barrows 5 Moderate >LOAEL Moderate >LOAEL

2 Moderate >LOAEL Minor >LOAEL

East of Welford Road (3 receptors)

NN2 8EU Cedrus Court 1 Moderate LOAEL

NN2 8TA Sherwood Avenue 2 Moderate LOAEL

West of Welford Road (80 receptors)

NN2 8PT Welford Road 8 Major >LOAEL Major >LOAEL

3 Major LOAEL

1 Major >LOAEL Moderate >LOAEL

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Short-term, daytime Short-term, night-time

Postcode Location Number Magnitude DS2021 Magnitude DS2021

1 Major LOAEL

19 Moderate >LOAEL Moderate >LOAEL

NN2 8UL Croxdale Close 1 Major LOAEL

1 Moderate LOAEL

NN2 8US Arndale 3 Major LOAEL

1 Major LOAEL

NN2 8UT Wensleydale 9 Major LOAEL

5 Moderate LOAEL

NN2 8UU Coverdale 8 Major LOAEL

4 Moderate LOAEL

NN2 8UW Martindale 1 Moderate LOAEL

NN2 8UY Garsdale 3 Major >LOAEL Major >LOAEL

9 Major LOAEL

1 Major LOAEL

2 Moderate LOAEL

Dallington Grange (1 receptor)

NN5 7PZ Grange Farm 1 Major >LOAEL Major >LOAEL

Brampton Lane (3 receptors)

NN6 8AA Brampton Lane 3 Moderate >LOAEL Moderate >LOAEL

7.6.9. Although impacts of minor magnitude are usually considered to be not significant, if the absolute noise level is high, further consideration might be warranted. 7.6.10. Table 7-32 (following) identifies eight residential receptors that are predicted to experience an adverse impact of minor magnitude in the short-term, and a noise level in DS2021 above the

SOAEL (68 dB LA10,18h façade).

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Table 7-32: Location and Number of Residential Receptors Subject to an Adverse Impact of Minor Magnitude in the Short-term and a Level above SOAEL

Short-term, daytime Short-term, night-time

Postcode Location Number Magnitude DS2021 Magnitude DS2021

West of Welford Road (8 receptors)

NN2 8EU Cedrus Court 1 Minor >SOAEL Minor >LOAEL

NN2 8PS Welford Road 6 Minor >SOAEL Minor >SOAEL

1 Minor >SOAEL Minor >LOAEL

Short-term Noise Decreases 7.6.11. It can be seen from Table 7-30 that 137 dwellings are predicted to experience a beneficial impact of moderate magnitude in the short-term during the day (138 at night) as a result of the Proposed Scheme, with a further 47 dwellings predicted to experience a beneficial impact of major magnitude during the day (21 at night). Of the other (non-residential) sensitive receptors, one is predicted to experience a beneficial impact of moderate magnitude (St Botolph’s Church) and one is predicted to experience a beneficial impact of major magnitude (The Bramptons Primary School). These impacts are relevant for the daytime period only, as it is assumed that these buildings would not be in use during the night-time period (see also section commencing at paragraph 7.6.41). 7.6.12. Table 7-33 provides a breakdown of the dwellings predicted to experience a beneficial impact of moderate and major magnitude in the short-term, according to postcode area and the absolute noise level in DS2021. Daytime and night-time levels have been considered as required by DMRB LA 111. As for the previously described analysis involving receptors with adverse impacts, those receptors with a noise level at or below the LOAEL in DS2021 have been discarded on the basis that the perception of road traffic noise, whilst noticeable, would not be intrusive and there should be no change to quality of life. Consequently, the following residential receptors (177 in number) are retained for further consideration.

Table 7-33: Location and Number of Residential Receptors Subject to a Beneficial Impact of Moderate and Major Magnitude in the Short-term

Short-term, daytime Short-term, night-time

Postcode Location Number Magnitude DM2021 Magnitude DM2021

Boughton Crossing (1 receptor)

NN6 8AB Welford Road 1 Major >SOAEL Major >SOAEL

Chapel Brampton (98 receptors)

NN6 8AE Northampton Road 3 Moderate >LOAEL Moderate >LOAEL

1 Moderate LOAEL

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Short-term, daytime Short-term, night-time

Postcode Location Number Magnitude DM2021 Magnitude DM2021

NN6 8AF Welford Road 1 Major >SOAEL Moderate >SOAEL

NN6 8AJ Back Lane 14 Major >LOAEL Major >LOAEL

8 Major >LOAEL Moderate >LOAEL

7 Moderate >LOAEL Moderate >LOAEL

3 Moderate LOAEL

NN6 8AL Little Close 1 Moderate >LOAEL Moderate >LOAEL

9 Moderate LOAEL

NN6 8AN Great Close 1 Major >LOAEL Moderate >LOAEL

3 Moderate >LOAEL Moderate >LOAEL

3 Moderate LOAEL

NN6 8AW Harlestone Road 2 Major >LOAEL Major >LOAEL

3 Major >LOAEL Moderate >LOAEL

6 Moderate >LOAEL Moderate >LOAEL

NN6 8BA Pitsford Road 14 Moderate >LOAEL Moderate >LOAEL

NN6 8BB Pitsford Road 1 Major >LOAEL Major >LOAEL

1 Major >LOAEL Moderate >LOAEL

NN6 8BD Pitsford Road 1 Moderate LOAEL

NN6 8BE Pitsford Road 3 Major >LOAEL Major >LOAEL

NN6 8BG Cedar Hythe 3 Moderate >LOAEL Moderate >LOAEL

1 Moderate LOAEL

1 Moderate >LOAEL Minor >LOAEL

NN6 8HE Spencer Close 8 Moderate >LOAEL Moderate >LOAEL

Church Brampton (78 receptors)

NN6 8AP Halfway Thorn 4 Major >SOAEL Moderate >SOAEL

3 Major >SOAEL Moderate >LOAEL

1 Major >LOAEL Moderate >LOAEL

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Short-term, daytime Short-term, night-time

Postcode Location Number Magnitude DM2021 Magnitude DM2021

NN6 8AR Harlestone Road 7 Moderate >SOAEL Moderate >SOAEL

NN6 8AU Harlestone Road 4 Major >LOAEL Moderate >LOAEL

3 Moderate >SOAEL Moderate >SOAEL

1 Moderate >SOAEL Moderate >LOAEL

24 Moderate >LOAEL Moderate >LOAEL

NN6 8AX Sandy Lane 3 Moderate >LOAEL Moderate >LOAEL

1 Moderate LOAEL

17 Moderate >LOAEL Minor >LOAEL

NN6 8AY Golf Lane 3 Moderate >LOAEL Moderate >LOAEL

1 Moderate LOAEL

NN6 8BN Road 3 Moderate >LOAEL Moderate >LOAEL

NN6 8DZ Walkers Lane 2 Moderate >LOAEL Moderate >LOAEL

HH6 8GN Jays Court 1 Moderate >LOAEL Moderate >LOAEL

7.6.13. As noted above, although impacts of minor magnitude are usually considered to be not significant, if the absolute noise level is high, further consideration might be warranted. 7.6.14. Table 7-34 identifies eleven residential receptors that are predicted to experience a beneficial impact of minor magnitude in the short-term, and a noise level in DM2021 above the SOAEL (68 dB

LA10,18h).

Table 7-34: Location and Number of Residential Receptors Subject to a Beneficial Impact of Minor Magnitude in the Short-term and a Level above SOAEL

Short-term, daytime Short-term, night-time

Postcode Location Number Magnitude DM2021 Magnitude DM2021

Chapel Brampton (11 receptors)

NN6 8AF Welford Road 8 Minor >SOAEL Minor >SOAEL

2 Minor >LOAEL Minor >SOAEL

1 Minor >SOAEL Negligible >SOAEL

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Long-term Noise Level Changes (2036) 7.6.15. Table 7-35 shows the predicted long-term change in noise level for all modelled receptors within the study area for the Proposed Scheme, sorted into the noise change bands following DMRB LA 111 magnitude of impact categories. Figure 7-7 in Appendix 7.4: Figures (Volume III of the EAS) presents a long-term noise change contour map showing the areas where noise levels increase and decrease with the Proposed Scheme in the long-term. 7.6.16. The magnitude of long-term noise impacts as a result of the Proposed Scheme range from major adverse to moderate beneficial. Broadly the impacts during the day and night are similar.

Table 7-35: Long-term Noise Changes with the Proposed Scheme

Daytime Night-time

Number of Number of other other Magnitude Number of sensitive Number of sensitive Change in noise level of impact dwellings receptors dwellings receptors *

Increase 0.1 – 2.9 dB Negligible 413 - 436 - in noise level 3.0 – 4.9 dB Minor 193 1 182 1 LA10,18h / Lnight 5.0 – 9.9 dB Moderate 68 1 57 1

≥ 10 dB Major 1 - 1 -

No change 0 dB No change - - - -

Decrease 0.1 – 2.9 dB Negligible 191 2 194 - in noise level 3.0 – 4.9 dB Minor 22 - 18 - LA10,18h / Lnight 5.0 – 9.9 dB Moderate 1 - 1 -

≥ 10 dB Major - - - -

Note: * There are two fewer entries in this column compared to the equivalent daytime column. This is because it is assumed that The Bramptons Primary School and St Botolph’s Church would generally not be in use during the night-time period

Long-term Noise Increases 7.6.17. It can be seen from Table 7-35 that 68 dwellings are predicted to experience an adverse impact of moderate magnitude in the long-term during the day (57 at night) as a result of the Proposed Scheme, with one other dwelling predicted to experience an adverse impact of major magnitude in the long-term during the day (one also at night). Of the other (non-residential) sensitive receptors, one is predicted to experience an adverse impact of minor magnitude (Brampton View Care Home) and one is predicted to experience an adverse impact of moderate magnitude (Meadow View Care Home). This is the case for both daytime and night-time periods.

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7.6.18. Table 7-36 provides a breakdown of the dwellings predicted to experience an adverse impact of minor, moderate and major magnitude in the long-term, according to postcode area and aligned with the associated short-term magnitude of impact as identified earlier in this section. Daytime and night-time levels have been considered as required by DMRB LA 111. 7.6.19. Table 7-36 includes residential receptors identified in Table 7-31 and Table 7-32 – 132 in total.

Table 7-36: Location and Number of Residential Receptors Subject to an Adverse Impact in the Short-term with Long-term Impacts Aligned

Short-term magnitude Long-term magnitude

Postcode Location Number Daytime Night-time Daytime Night-time

Buckton Fields East (37 receptors)

NN2 8ES Home Farm Drive 1 Moderate Moderate Moderate Minor

8 Moderate Moderate Minor Minor

1 Moderate Minor Minor Minor

NN2 8EX Bochetone 1 Moderate Moderate Moderate Minor

8 Moderate Moderate Minor Minor

1 Moderate Minor Minor Minor

NN2 8EZ Hanging Barrows 1 Moderate Minor Minor Minor

NN2 8FA Tiggyhole 9 Moderate Moderate Minor Minor

NN2 8FB Far Barrows 5 Moderate Moderate Minor Minor

2 Moderate Minor Minor Minor

East of Welford Road (11 receptors)

NN2 8EU Cedrus Court 1 Moderate Moderate Minor Minor

1 Minor Minor Negligible Negligible

NN2 8PS Welford Road 7 Minor Minor Negligible Negligible

NN2 8TA Sherwood Avenue 2 Moderate Moderate Minor Minor

West of Welford Road (80 receptors)

NN2 8PT Welford Road 11 Major Major Moderate Moderate

2 Major Moderate Moderate Minor

1 Moderate Moderate Moderate Minor

18 Moderate Moderate Minor Minor

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Short-term magnitude Long-term magnitude

Postcode Location Number Daytime Night-time Daytime Night-time

NN2 8UL Croxdale Close 1 Major Major Moderate Moderate

1 Moderate Moderate Moderate Moderate

NN2 8US Arndale 3 Major Major Moderate Moderate

1 Major Moderate Moderate Moderate

NN2 8UT Wensleydale 9 Major Major Moderate Moderate

1 Moderate Moderate Moderate Moderate

2 Moderate Moderate Moderate Minor

2 Moderate Moderate Minor Minor

NN2 8UU Coverdale 8 Major Major Moderate Moderate

3 Moderate Moderate Moderate Moderate

1 Moderate Moderate Minor Minor

NN2 8UW Martindale 1 Moderate Moderate Minor Minor

NN2 8UY Garsdale 12 Major Major Moderate Moderate

1 Major Moderate Moderate Moderate

1 Moderate Moderate Moderate Minor

1 Moderate Moderate Minor Minor

Dallington Grange (1 receptor)

NN5 7PZ Grange Farm 1 Major Major Major Major

Brampton Lane (3 receptors)

NN6 8AA Brampton Lane 3 Moderate Moderate Minor Minor

Long-term Noise Decreases 7.6.20. It can be seen from Table 7-35 that a single dwelling is predicted to experience a beneficial impact of moderate magnitude in the long-term during the day (one also at night) as a result of the Proposed Scheme. 7.6.21. Table 7-37 provides a breakdown of the dwellings predicted to experience a beneficial impact of minor and moderate magnitude in the long-term, according to postcode area and aligned with the associated short-term magnitude of impact as identified earlier in this section. Daytime and night- time levels have been considered as required by DMRB LA 111.

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7.6.22. Table 7-37 includes residential receptors identified in Table 7-33 and Table 7-34 – 188 in total.

Table 7-37: Location and Number of Residential Receptors Subject to a Beneficial Impact in the Short-term with Long-term Impacts Aligned

Short-term magnitude Long-term magnitude

Postcode Location Number* Daytime Night-time Daytime Night-time

Boughton Crossing (1 receptor)

NN6 8AB Welford Road 1 Major Major Moderate Moderate

Chapel Brampton (109 receptors)

NN6 8AE Northampton Road 4 (2) Moderate Moderate Negligible Negligible

NN6 8AF Welford Road 1 (1) Major Moderate Negligible Negligible

10 (10) Minor Minor Negligible Negligible

1 (1) Minor Negligible Negligible Negligible

NN6 8AJ Back Lane 13 Major Major Minor Minor

1 (1) Major Major Negligible Negligible

5 Major Moderate Minor Minor

3 Major Moderate Negligible Negligible

3 Moderate Moderate Minor Negligible

7 Moderate Moderate Negligible Negligible

NN6 8AL Little Close 10 Moderate Moderate Negligible Negligible

NN6 8AN Great Close 1 Major Moderate Negligible Negligible

6 Moderate Moderate Negligible Negligible

NN6 8AW Harlestone Road 2 (2) Major Major Negligible Negligible

3 Major Moderate Negligible Negligible

6^ (2) Moderate Moderate Negligible Negligible

NN6 8BA Pitsford Road 14 Moderate Moderate Negligible Negligible

NN6 8BB Pitsford Road 1 Major Major Negligible Negligible

1 Major Moderate Negligible Negligible

NN6 8BD Pitsford Road 1 Moderate Moderate Negligible Negligible

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Short-term magnitude Long-term magnitude

Postcode Location Number* Daytime Night-time Daytime Night-time

NN6 8BE Pitsford Road 3 Major Major Negligible Negligible

NN6 8BG Cedar Hythe 4 Moderate Moderate Negligible Negligible

1 Moderate Minor Negligible Negligible

NN6 8HE Spencer Close 8 Moderate Moderate Negligible Negligible

Church Brampton (78 receptors)

NN6 8AP Halfway Thorn 8 Major Moderate Negligible Negligible

NN6 8AR Harlestone Road 7 Moderate Moderate Negligible Negligible

NN6 8AU Harlestone Road 4 Major Moderate Negligible Negligible

28 Moderate Moderate Negligible Negligible

NN6 8AX Sandy Lane 4 Moderate Moderate Negligible Negligible

17 Moderate Minor Negligible Negligible

NN6 8AY Golf Lane 4 Moderate Moderate Negligible Negligible

NN6 8BN Holdenby Road 3 Moderate Moderate Negligible Negligible

NN6 8DZ Walkers Lane 2 Moderate Moderate Negligible Negligible

HH6 8GN Jays Court 1 Moderate Moderate Negligible Negligible

Notes: * The figures in brackets in this column refer to the number of receptors that have either a negligible adverse impact or no change in the long-term (in the range ±0.0 to +0.6 dB), rather than a negligible beneficial impact. This is the case for both daytime and night-time periods. ^ Of the six receptors in this group, two have a negligible adverse impact in the long-term, during the day and night. Three receptors have a negligible beneficial impact in the long-term, during the day and night, whilst one receptor has a negligible beneficial impact in the long-term, during the day and no change at night.

Significance of Effects 7.6.23. Table 7-36 identifies 132 receptors with an adverse impact of minor, moderate or major magnitude in the short-term, whilst Table 7-37 identifies 188 receptors with a beneficial impact of minor, moderate or major magnitude in the short-term. There is no overlap between these two groups of receptors. 7.6.24. To determine whether a significant effect is likely to arise at these 320 receptors, contextual factors beyond the predicted short-term change in noise need to be considered. One of these factors is the long-term change in noise and another is the absolute level of noise.

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7.6.25. Table 7-38 identifies receptors with a short-term change of minor magnitude that are considered not significant, with the reasons stated beneath the table. 7.6.26. In the table the trigger for potential significance – a short-term change of minor magnitude (at least

1.0 dB) and a DS2021 level above SOAEL (68 dB LA10,18h façade during the day and 55 dB

Lnight,outside free-field during the night) – is identified in blue. The magnitude of impact is described in brackets with ‘min’ and ‘neg’ and ‘n/c’ referring to minor, negligible and no change respectively.

Table 7-38: Receptors with a Short-term Change of Minor Magnitude Determined to be Not Significant

Daytime (LA10,18h façade) Night-time (Lnight,outside free-field)

Postcode No. 2021* ST change LT change 2021* ST change LT change

Increase (8 receptors)

NN2 8EU 1 68.9 dB +1.3 (min) +1.2 (neg) 45.5 dB +1.2 (min) +1.2 (neg)

NN2 8PS 1 68.9 dB +1.2 (min) +1.0 (neg) 55.7 dB +1.0 (min) +1.0 (neg)

2 68.6 dB +1.2 (min) +1.1 (neg) 55.5 dB +1.1 (min) +1.1 (neg)

1 68.3 dB +1.2 (min) +1.1 (neg) 54.5 dB +1.1 (min) +1.1 (neg)

1 68.2 dB +1.3 (min) +1.1 (neg) 55.1 dB +1.1 (min) +1.1 (neg)

1 68.2 dB +1.2 (min) +1.1 (neg) 55.1 dB +1.1 (min) +1.1 (neg)

1 68.1 dB +1.2 (min) +1.1 (neg) 55.1 dB +1.1 (min) +1.1 (neg)

Decrease (2 receptors)

NN2 8EU 1 68.8 dB -1.3 (min) +0.1 (neg) 55.6 dB -1.2 (min) +0.1 (neg)

1 64.0 dB -1.2 (min) +0.0 (n/c) 55.4 dB -1.0 (min) +0.1 (neg)

Note: * The reported noise level in 2021 is the higher of the DM2021 and DS2021 levels. For receptors subject to an increase in noise this will be the DS2021 level and for receptors subject to a decrease in noise this will be the DM2021 level

7.6.27. The receptors in Table 7-38 are considered not significant for the following reasons:  The 2021 noise level is less than 1 dB above the SOAEL threshold  The change is at the lower end of the minor category (up to ±1.3 dB)  The long-term change is only negligible (for one receptor during the daytime, there is no change) 7.6.28. Table 7-39 identifies receptors with a short-term change of moderate magnitude that are considered not significant, with the reasons stated beneath the table.

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7.6.29. In the table the trigger for potential significance – a short-term change of moderate magnitude (at

least 3.0 dB) and a DS2021 level above LOAEL (55 dB LA10,18h façade during the day and 40 dB

Lnight,outside free-field during the night) – is identified in blue. The magnitude of impact is described in brackets with ‘mod’, ‘min’ and ‘neg’ referring to moderate, minor and negligible respectively.

Table 7-39: Receptors with a Short-term Change of Moderate Magnitude Determined to be Not Significant

Daytime (LA10,18h façade) Night-time (Lnight,outside free-field)

Postcode No. 2021* ST change LT change 2021* ST change LT change

Increase (5 receptors)

NN2 8ES 1 55.4 dB +3.1 (mod) +4.0 (min) 43.7 dB +2.7 (min) +3.5 (min)

NN2 8EU 1 51.4 dB +3.3 (mod) +3.5 (min) 40.2 dB +3.1 (mod) +3.3 (min)

NN2 8EX 1 55.4 dB +3.0 (mod) +4.0 (min) 43.7 dB +2.8 (min) +3.6 (min)

NN2 8TA 1 52.0 dB +3.3 (mod) +3.5 (min) 40.6 dB +3.2 (mod) +3.3 (min)

1 51.9 dB +3.2 (mod) +3.3 (min) 40.4 dB +3.0 (mod) +3.1 (min)

Decrease (1 receptor)

NN6 8AJ 1 52.4 dB -3.1 (mod) -1.9 (neg) 40.5 dB -3.0 (min) -1.9 (neg)

Note: * The reported noise level in 2021 is the higher of the DM2021 and DS2021 levels. For receptors subject to a noise increase this will be the DS2021 level and for receptors subject to a noise decrease this will be the DM2021 level

7.6.30. The receptors in Table 7-39 are considered not significant for the following reasons:  Only the daytime or the night-time has a moderate adverse change and a level above LOAEL  The 2021 noise level is less than 1 dB above the LOAEL threshold  The change is at the lower end of the moderate category (up to ±3.3 dB)  The long-term change is only minor adverse (for receptors with an increase) or negligible beneficial (for the receptor with a decrease) 7.6.31. Table 7-40 summarises the receptors likely to experience a significant effect having accounted for those receptors (in Table 7-38 and Table 7-39) where the effect is deemed to be not significant. The column heading ST refers to the short-term magnitude of change in the opening year, with ‘min’, ‘mod’ and ‘maj’ referring to a short-term change of minor, moderate and major magnitude respectively. 7.6.32. Figure 7-8 in Appendix 7.4: Figures (Volume III of the ESA) identifies the receptors subject to a significant effect.

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Table 7-40: Receptors Considered Likely to Experience a Significant Effect

Significant Adverse Effects Significant Beneficial Effects

Postcode Location No. ST Postcode Location No. ST

Buckton Fields East (35 receptors) Boughton Crossing (1 receptor)

NN2 8ES Home Farm Drive 9 mod NN6 8AB Welford Road 1 maj

NN2 8EX Bochetone 9 mod Chapel Brampton (106 receptors)

NN2 8EZ Hanging Barrows 1 mod NN6 8AE Northampton Road 4 mod

NN2 8FA Tiggyhole 9 mod NN6 8AF Welford Road 1 maj

NN2 8FB Far Barrows 7 mod 9 min

West of Welford Road (80 receptors) NN6 8AJ Back Lane 22 maj

NN2 8PT Welford Road 13 maj 9 mod

19 mod NN6 8AL Little Close 10 mod

NN2 8UL Croxdale Close 1 maj NN6 8AN Great Close 1 maj

1 mod 6 mod

NN2 8US Arndale 4 maj NN6 8AW Harlestone Road 5 maj

NN2 8UT Wensleydale 9 maj 6 mod

5 mod NN6 8BA Pitsford Road 14 mod

NN2 8UU Coverdale 8 maj NN6 8BB Pitsford Road 2 maj

4 mod NN6 8BD Pitsford Road 1 mod

NN2 8UW Martindale 1 mod NN6 8BE Pitsford Road 3 maj

NN2 8UY Garsdale 13 maj NN6 8BG Cedar Hythe 5 mod

2 mod NN6 8HE Spencer Close 8 mod

Dallington Grange (1 receptor) Church Brampton (78 receptors)

NN5 7PZ Grange Farm 1 maj NN6 8AP Halfway Thorn 8 maj

Brampton Lane (3 receptors) NN6 8AR Harlestone Road 7 mod

NN6 8AA Brampton Lane 3 mod NN6 8AU Harlestone Road 4 maj

28 mod

NN6 8AX Sandy Lane 21 mod

NN6 8AY Golf Lane 4 mod

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Significant Adverse Effects Significant Beneficial Effects

Postcode Location No. ST Postcode Location No. ST

NN6 8BN Holdenby Road 3 mod

NN6 8DZ Walkers Lane 2 mod

NN6 8GN Jays Court 1 mod

Summary of Significant Adverse Effects 7.6.33. Significant adverse effects arise in three areas.  Brampton Lane (including Buckton Fields East);  West of Welford Road; and  Dallington Grange. 7.6.34. Adverse impacts of moderate magnitude (significant) are predicted along Brampton Lane and, in particular, at 35 recently constructed dwellings along the northern (and western) edge of the Buckton Fields East development and at three existing dwellings further west. At seven of these recently constructed dwellings, daytime noise levels are predicted to increase from below the SOAEL to above in 2021 as a result of the Proposed Scheme. During the night-time period five dwellings are similarly affected, but these are a sub-set of the seven dwellings affected during the day. 7.6.35. The reason for the significant effects is the intensification of traffic on Brampton Lane as a result of the Proposed Scheme, as Table 7-41 (following) demonstrates. Brampton Lane is divided into three sections in the traffic model. The Basic Noise Level (at 10 m from the nearside kerb) has been determined in accordance with the CRTN (see paragraph 7.3.10 and associated footnote). 7.6.36. The 18-hour flow, percentage of heavy-duty vehicles (hdv) and average speed (in kph) have been considered. An allowance of -1 dB for road surface has also been included as vehicle speeds in all scenarios and on all links, are below 75 kph.

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Table 7-41: Basic Noise Level Calculations along Brampton Lane

Link 1236-3236 (west) Link 1236-36033 (centre) Link 2236-36033 (east)

Year Flow %hdv kph BNL Flow %hdv kph BNL Flow %hdv kph BNL

DM21 6,728 2 51 64.5 6,546 2 46 63.9 7,006 2 38 63.4

DM36 10,047 1 50 65.7 9,849 1 45 65.1 11,628 1 38 65.2

DS21 17,197 2 50 68.4 17,022 2 45 67.9 17,474 2 38 67.4

DS36 23,435 1 49 69.3 23,246 1 45 68.9 24,980 1 38 68.5

STds +3.9 +4.0 +4.0

LTds +4.8 +5.0 +5.1

LTdm +1.2 +1.2 +1.8

Abbreviations: Flow = 18-hour AAWT flow; %hdv = percentage heavy duty vehicles; kph = average speed in kilometres per hour

BNL is the Basic Noise Level at 10 m from the nearside kerb in terms of dB LA10,18h free-field STds = short-term Do-Something noise change (DM2021-DS2021), LTds = long-term Do-Something noise change (DM2021-DS2036) and LTdm = long-term Do-Minimum noise change (DM2021-DM2036) DM = Do-Minimum; DS = Do-Something. 2021 (opening year), 2036 (future year)

7.6.37. From Table 7-41, it can be concluded that the short-term noise changes and the majority of the long-term noise changes, are a by-product of the Proposed Scheme. As Brampton Lane falls outside the planning red line boundary, noise barriers and low noise surfaces are not currently an option. In addition, traffic speeds are too low to result in any claimable noise reduction if a low noise road surface were to be laid. Significant adverse effects are therefore predicted to result at the receptors on Brampton Lane. 7.6.38. Significant adverse effects are also noted west of Welford Road, to the east of the Proposed Scheme with adverse impacts of moderate and major magnitude (significant) predicted at 80

dwellings. Whilst noise levels at these dwellings (LA10,18h façade in 2021 with the Proposed Scheme)

are predicted to be at least 51.5 dB, they are also below 57.5 dB (approximately 53 dB LAeq,16h free- field10), so whilst the noise changes are notable, the overall environmental noise levels are not high. 7.6.39. Mitigation for these receptors is considered in the section commencing at paragraph 7.6.83. 7.6.40. An adverse impact of major magnitude (significant) is predicted at Grange Farm to the south-west of the Proposed Scheme in both the short and long-term. It is understood that Grange Farm is identified for redevelopment as part of the Dallington Grange development. The timing of redevelopment is not known, so to be cautious the potential for a significant effect has been reported.

10 For context, the WHO Guidelines for Community Noise (Ref. 7-14) state that “During the daytime, few people are seriously annoyed by activities with LAeq levels below 55 dB; or moderately annoyed with LAeq levels below 50 dB”.

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Summary of Significant Beneficial Effects 7.6.41. Significant beneficial effects arise in three areas.  Boughton Crossing;  Chapel Brampton; and  Church Brampton. 7.6.42. A beneficial impact of major magnitude (significant) is predicted at Broughton Crossing to the north of the Proposed Scheme in the short-term. In the long-term the beneficial impact is of moderate magnitude. This dwelling lies very close to part of Welford Road that is made stopped-up as a result of the Proposed Scheme and as a result daytime and night-time noise levels are predicted to decrease from above the SOAEL to below in 2021. 7.6.43. In Chapel Brampton beneficial impacts of minor, moderate and major magnitude (significant) are predicted at 106 dwellings. At five dwellings, night-time noise levels are predicted to decrease from above the SOAEL to below in 2021 as a result of the Proposed Scheme. During the daytime period three dwellings are similarly affected, but these are a sub-set of the five dwellings affected during the night. 7.6.44. In Church Brampton beneficial impacts of moderate and major magnitude (significant) are predicted at 78 dwellings. At 18 dwellings, daytime noise levels are predicted to decrease from above the SOAEL to below in 2021 as a result of the Proposed Scheme. During the night-time period 14 dwellings are similarly affected, but these are a sub-set of the 18 dwellings affected during the day. Other Sensitive Receptors 7.6.45. There are four other sensitive receptors identified in the defined study area and considered in this assessment (see paragraph 7.3.14). 7.6.46. The predicted magnitude of impact in the short-term and long-term and during the day and night as a result of the Proposed Scheme is tabulated below. Table 7-42: Predicted Impacts at Other Sensitive Receptors in the Short-term and Long-term and for Daytime and Night-time Periods

Short-term impact Long-term impact Adverse / Receptor beneficial Daytime Night-time Daytime Night-time

The Bramptons Primary School Beneficial Major n/a Negligible n/a

Brampton View Care Home Adverse Moderate Moderate Minor Minor

Meadow View Care Home Adverse Major Major Moderate Moderate

St Botolph’s Church Beneficial Moderate n/a Negligible n/a

7.6.47. The tabulated impacts are such that these receptors are considered likely to experience a significant effect – adverse for the two care homes and beneficial for the school and church.

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Golf Courses 7.6.48. Figure 7-6 and Figure 7-7 in Appendix 7.4: Figures (Volume III of the ESA) show that adverse impacts along the eastern fringe of both golf courses (Brampton Heath Golf Centre and Northamptonshire County Golf Club) are of major magnitude in both the short and long-term. This magnitude of noise change is predicted as the Proposed Scheme runs parallel with, and in close proximity to, the eastern boundary of both courses. 7.6.49. This magnitude of noise change only applies along the eastern boundary of each golf course. The degree of change reduces away from the Proposed Scheme with the club house on the western side of each golf course subject to a much smaller adverse impact of minor magnitude in the short- term and negligible magnitude in the long-term. There is even a potential improvement (of similar magnitude) predicted on the club house façades facing away from the Proposed Scheme and towards roads that are relieved by it. 7.6.50. Paragraph 7.6.37 identified that overall noise levels within the Proposed Scheme corridor are not that high. For example, the eastern fringe of the Brampton Heath Golf Centre has a predicted

DS2036 free-field noise level of around 62 dB LA10,18h (approximately 60 dB LAeq,16h), but a

substantial part of the course would be subject to levels below 57 dB LA10,18h (approximately 55 dB 11 LAeq,16h) and even below 52 dB LA10,18h (approximately 50 dB LAeq,16h) . 7.6.51. The use of the golf courses would be occasional and transient, and the same degree of sensitivity would therefore not be applied to this receptor as has been assumed for the residential and other sensitive receptors. Despite the adverse impacts of major magnitude along the eastern side of each course in the short and long-term, noise levels over much of each golf course are predicted to be

below 57 dB LA10,18h (approximately 55 dB LAeq,16h). Consequently, and on balance, the noise levels and changes predicted to affect each golf course are considered not significant. National Cycle Route 6 7.6.52. Figure 7-6 in Appendix 7.4: Figures (Volume III of the ESA) shows that within the study area between the railway and the Brampton Lane Roundabout, adverse impacts of minor, moderate and major magnitude are predicted in the short-term. Figure 7-7 in Appendix 7.4: Figures (Volume III of the ESA) shows that in the long-term, adverse impacts of minor and moderate magnitude are predicted. 7.6.53. As for the golf courses, overall noise levels are not high. Of the section of the cycle route that falls

within the study area, the southern end has a predicted level below 52 dB LA10,18h (approximately

50 dB LAeq,16h), with much of the remaining route falling within the range 52-57 dB LA10,18h

(approximately 50-55 dB LAeq,16h). It is only further north, where the cycle route approaches the

Brampton Lane Roundabout, that levels rise above 57 dB LA10,18h (approximately 55 dB LAeq,16h). 7.6.54. The use of the cycle route is expected to be transient and occasional such that exposure to the highest noise levels and highest noise changes would be limited. With overall levels lower than along the eastern fringe of the golf courses due to the increased separation distance, and with slightly lower noise changes, the proposed noise changes on the National Cycle Route 6 are also considered not significant.

11 See previous footnote (7) for context.

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Planning Applications 7.6.55. The section commencing at paragraph 7.3.17 identified potentially noise-sensitive residential developments in the vicinity of the Proposed Scheme that have been approved and are currently in the process of being constructed. These are shown in Figure 3-1: Committed Developments (Volume IV of the ESA). 7.6.56. The comments in this section are based on the predicted noise level changes presented in Figure 7-6 and Figure 7-7, included in Appendix 7.4: Figures (Volume III of the ESA). The anticipated impacts on the residential developments have been described considering the noise contours across the undeveloped site, although where relevant and appropriate, consideration has also been given to the likely noise impacts with the dwellings constructed and occupied, based on the noise contours across adjacent areas. Welford Road 7.6.57. In DS2036 the highest noise levels would be experienced on the east side of the site adjacent to Welford Road. The centre line of the Main Carriageway would be approximately 290 m away (at the nearest point), although the Causeway is approximately 140 m from the northern boundary of the

Welford Road development. In 2036 with the Proposed Scheme, the following noise levels (LA10,18h free-field) are predicted, based on an open site:  56-58 dB at the western boundary of the site; and  65-66 dB to the east, 10 m from the kerb of Welford Road. 7.6.58. Based on the noise change contour maps referred to in paragraph 7.6.51, the open site would be subject to adverse impacts of minor magnitude in the short-term and negligible magnitude in the long-term. 7.6.59. However, once the development is constructed, those buildings located close to Welford Road would screen others behind from the dominant road traffic noise source (Welford Road).Whilst noise levels in the western part of the site would be expected to reduce, the magnitude of noise change in this area would be expected to increase as the noise contribution from the Proposed Scheme becomes more influential. Noise impacts on the completed site would be likely to resemble the impacts at existing properties immediately to the south on Welford Road:  in the short-term, adverse impacts of no more than minor magnitude on façades facing towards and fronting Welford Road, with adverse impacts of up to major magnitude on façades facing towards the Proposed Scheme; and  in the long-term, impacts of no more than negligible magnitude on façades facing towards and fronting Welford Road, with adverse impacts of up to moderate magnitude on façades facing towards the Proposed Scheme. 7.6.60. In summary, if dwellings on the eastern half of the site (away from Welford Road) were to be completed and occupied prior to the Proposed Scheme opening, adverse impacts of up to major magnitude (significant) would be expected. Buckton Fields West 7.6.61. Based on the noise change contour maps referred to in paragraph 7.6.51, it can be seen that the open site overall would be subject to adverse impacts of moderate and minor magnitude in the short-term, with the higher impacts near Brampton Lane and lower impacts applicable elsewhere.

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7.6.62. The impacts along the northern boundary, adjacent to Brampton Lane, result from the intensification of traffic on that road as noted in the section commencing at paragraph 7.6.32. 7.6.63. In the long-term, adverse impacts would generally be no greater than of minor magnitude, with impacts of negligible magnitude along the southern boundary and adjacent to Welford Road on the west side of the Buckton Fields development, which is the boundary closest to the Proposed Scheme. 7.6.64. This development has only recently commenced construction and from early mapping it is clear that it is the southern half of the site that is being development initially. As the area adjacent to Brampton Lane would be unlikely to be constructed and occupied prior to the opening of the Proposed Scheme, the adverse impacts of moderate magnitude would most likely not be experienced. Instead, adverse impacts would most likely be no greater than of minor magnitude in both the short- term and long-term. 7.6.65. In summary, as the current phase of development is in the southern half of the site adverse impacts of no greater than minor magnitude (not significant) would be expected. Dallington Grange 7.6.66. Based on the noise change contour maps referred to in paragraph 7.6.51, the open site would be subject to a range of impacts in the short-term – both beneficial and adverse. In the long-term adverse impacts of minor, moderate and major magnitude are predicted, but this would also be the case in the long-term without the Proposed Scheme (see Figure 7-5 in Appendix 7.4: Figures (Volume III of the ESA)). 7.6.67. The impacts affecting the Dallington Grange development are influenced more by the build-out assumptions surrounding the infrastructure required to support the Dallington Grange development, rather than the Proposed Scheme. 7.6.68. The Dallington Grange development is inextricably linked to the road infrastructure upon which it relies. On the basis that the proposed buildings would be suitably located, orientated, designed and constructed to take full account of future traffic movements on the emerging highway infrastructure it is assumed that any residual adverse effects would be not significant. Wider Road Network Analysis 7.6.69. The noise assessment undertaken has focussed on the detailed predictions generated by the noise model in the traffic noise study area (see Figure 7-3 in Appendix 7.4: Figures (Volume III of the ESA). However, there is potential for the Proposed Scheme to have an impact beyond the main study area. Consequently, a BNL assessment has been undertaken along the wider road network (i.e. outside the main study area) using the traffic data provided by the Design Team. 7.6.70. This assessment determines whether a change of 3 dB or more in the short-term and/or 5 dB or more in the long-term is predicted (i.e. an impact of moderate or major magnitude respectively). The assessment includes both short-term and long-term changes in noise and considers beneficial as well as adverse impacts. 7.6.71. In the following assessment, the predicted noise changes are defined as follows:  Short-term: 2021 opening year Do-Minimum vs. 2021 opening year Do-Something; and  Long-term: 2021 opening year Do-Minimum vs. 2036 future year Do-Something.

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7.6.72. Appendix 7.9: BNL Calculations – Wider Road Network (Volume III of the ESA) contains detailed BNL calculations, whilst Table 7-43 provides a summary. The table excludes any links that:  lie within the main study area (and which have been considered in the modelled results presented earlier in this section); and  fall within the Dallington Grange development, where impacts are influenced more by the build- out assumptions surrounding the infrastructure required to support the Dallington Grange development rather than the Proposed Scheme. 7.6.73. Only impacts of moderate or major magnitude arising from the Proposed Scheme have been identified in Appendix 7.9: BNL Calculations – Wider Road Network (Volume III of the ESA) and the following table.

Table 7-43: Road Links with an Impact of Moderate or Major Magnitude Within the Wider Network

Impact magnitude with Proposed Scheme

Road Link Location Short-term Long-term

10035-12087 Keyston (Toll Bar Lane and B663) Moderate benefit* Negligible

12259-12289 (Manor Street and Park Road) Moderate benefit* No change

12286-12289 Raunds (Butts Road) Moderate benefit* No change

1268-4102 Upton Valley Way East Moderate benefit^ Minor adverse

1267-1268 Upton Valley Way East Moderate benefit^ Minor adverse

7021-9931 High Street, Kingsthorpe Moderate adverse° Minor adverse

Notes: * These links have 18-hour AAWT flows of less than 1,600 in all scenarios. CRTN requires a ‘low flow’ correction to be applied where the 18-hour AAWT flow lies in the range 1,000 to 4,000. ^ These links have 18-hour AAWT flows of less than 1,600 in the relevant scenarios (DM2021 and DS2021). ° This link has 18-hour AAWT flows of less than 2,650 in all scenarios. Also, average speeds are less than 10 mph (16 kph) in all scenarios, although these have all been increased to 20 kph for the BNL calculations.

7.6.74. Table 7-43 reports that all links are predicted to experience an impact of moderate magnitude in the short-term, with more of these being beneficial than adverse. There are no links predicted to experience an impact of major magnitude. 7.6.75. There are notable benefits in Keyston and Raunds, which lie in excess of 27 kilometres to the east. However, these links carry less than 1,600 vehicles in all scenarios (opening and future year), regardless of the presence of the Proposed Scheme. This light volume of traffic attracts a ‘low flow’ correction in the CRTN prediction methodology (see the notes in Table 7-43) and on this basis, overall noise levels at receptors adjacent to these links are expected to be fairly modest. 7.6.76. There are also notable benefits along Upton Valley Way East, over five kilometres to the south. Again, these links carry less than 1,600 in the opening year regardless of the presence of the Proposed Scheme.

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7.6.77. It can be seen that there is a single link predicted to experience impacts of moderate adverse magnitude. This link is considered further in the table following. Table 7-44 - Further Consideration of Road Link with an Impact of Moderate Adverse Magnitude

Link Location Comments

7021-9931 High Street, This is a short link (one-way in part) in the centre of town between the A5199 Kingsthorpe Welford Road and A508 Harborough Road. An adverse impact of minor magnitude is recorded in the long-term, whilst in the short-term an adverse impact of moderate magnitude is triggered by 0.8 dB. 18-hour AAWT flows are low with no scenario carrying more than 2,650 vehicles. Average speeds are less than 10 mph (16 kph) in all scenarios.

7.6.78. In summary, it can be seen that impacts of moderate magnitude are predicted along a number of links outside the main study area, both beneficial and adverse. However, to conclude whether these changes are likely to be significant, it is necessary to consider contextual factors including:  the relatively low traffic flows, which will serve to limit the absolute noise levels (see paragraph 7.6.74);  the magnitude of short-term change, which falls at the lower end of the moderate range;  the magnitude of long-term change, which is of no greater impact than minor; and  the link location, which in most cases is some distance from the Proposed Scheme. 7.6.79. Notwithstanding the predicted changes of moderate magnitude, it is predicted that those potentially affected by road traffic noise from these links, would be unlikely to perceive the changes as significant and that their behaviour or response to noise would be unlikely to change. The overall conclusion is that the predicted noise changes are likely to be not significant. Summary 7.6.80. The significant effects noted above are summarised in this section. The reported significance of effect is based on the short-term change in noise (comparing the situation in 2021 with and without the Proposed Scheme), although other contextual factors such as the absolute noise level have also been considered. For the residential receptors tabulated below, the resultant adverse effect would be direct, permanent and significant.

Table 7-45: Summary of Significant Adverse Effects – Residential Receptors

Magnitude of adverse impact (short-term)

Location Minor Moderate Major Total

Dallington Grange 0 0 1 1

Brampton Lane (incl. Buckton Fields East) 0 38 0 38

West of Welford Road 0 32 48 80

Total 0 70 49 119

7.6.81. For the residential receptors tabulated below, the resultant beneficial effect would be direct, permanent and significant.

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Table 7-46: Summary of Significant Beneficial Effects – Residential Receptors

Magnitude of beneficial impact (short-term)

Location Minor Moderate Major Total

Broughton Crossing 0 0 1 1

Chapel Brampton 9 63 34 106

Church Brampton 0 66 12 78

Total 9 129 47 185

7.6.82. For the following non-residential (but still noise sensitive) receptors, the resultant adverse effect would be direct, permanent and significant:  Brampton View Care Home (NN6 8GH)  Meadow View Care Home (NN2 8PT) 7.6.83. For the following non-residential (but still noise sensitive) receptors, the resultant beneficial effect would be direct, permanent and significant:  The Bramptons Primary School (NN6 8AW)  St Botolph’s Church (NN6 8AU) 7.6.84. As noted in paragraph 7.3.18, there are a number of developments in the vicinity of the Proposed Scheme, where at least some dwellings might be completed and occupied before the Proposed Scheme opens. At Welford Road, construction has also recently commenced. If dwellings on the eastern half of the site (away from Welford Road) were to be completed and occupied prior to the Proposed Scheme opening, adverse impacts of up to major magnitude (significant) would be expected. MITIGATION MEASURES 7.6.85. It has already been noted (in paragraph 7.6.33) that the significant adverse effects that are predicted at recently constructed and existing dwellings along Brampton Lane are a by-product of the Proposed Scheme and that as these fall outside the red line boundary of the Proposed Scheme, mitigation is not a realistic option and significant residual effects will remain at this location. Consideration of Secondary Mitigation 7.6.86. The operational road traffic noise assessment described above concludes that significant adverse effects are predicted in areas west of Welford Road as a result of the Proposed Scheme. Therefore, it is necessary to consider introducing mitigation to reduce noise at sensitive receptors in this area. To this end, a barrier with the following details has been considered:  located as close to the east side of the road as possible (a 3 m off-set has been modelled)  3 m high  in two parts, a northern section 502 m long and a southern section 189 m long. The two parts are separated by a gap of 15 m, which is required to provide access to a track leading to drainage features associated with the Proposed Scheme.

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7.6.87. Although now superseded by DMRB LA 111, DMRB HD 213/11 provided some useful guidance on the potential benefits that can be achieved with barriers “the potential benefits of mitigation measures vary widely according to circumstances. For example, environmental barriers can provide reductions of 10 dB or more for well-screened locations relatively close to the source. But at further distances, and especially where the barrier provides only a small deflection of the transmitted sound waves, actual noise reductions may only be 1 or 2 dB. Beyond 200-300m, the effects are often zero as ground attenuation becomes the most significant factor.” 7.6.88. Given that the nearest properties (to the west of Welford Road) are around 300 m from the Main Carriageway, only modest benefits are anticipated, and this is borne-out by the results of the modelling with just a single receptor likely to have a reduction of more than 3 dB. 7.6.89. Typical reductions are in the range 1-2 dB (at properties most likely to benefit from such a barrier) and this magnitude of change will result in the noise level at some properties falling below the

daytime LOAEL (55 dB LA10,18h façade). Furthermore, some of the major and moderate changes would be expected to fall within a lower category. However, the introduction of a barrier would not result in all properties having an absolute DS2036 noise level below the LOAEL, nor a noise change that is no higher than of minor magnitude. Hence, significant residual effects would remain at some properties. 7.6.90. Based on the assessment and findings described above, no barrier is proposed as:  It would provide only modest acoustic benefits; and  Significant effects would still remain for some properties 7.6.91. Furthermore, unless an absorptive barrier were erected, there is potential for such a barrier to reflect noise towards the more northerly golf course to the west (Brampton Heath Golf Centre). Tertiary Mitigation 7.6.92. As noted in paragraph 7.3.67, any assessment under the terms of the Noise Insulation Regulations (NIR) will be indicative at this stage. The NIR assessment requires the following criteria to be met:  A relevant noise level (the noise level in the future year with the Proposed Scheme) of at least

68 dB LA10,18h (façade);  A noise increase between the relevant noise level and the prevailing noise level (immediately before the works to construct the highway are commenced) of at least 1 dB(A);  A contribution to the increase in the relevant noise level from the Proposed Scheme of at least 1 dB(A); and  The dwelling must lie within 300 m of the Proposed Scheme. 7.6.93. A number of dwellings are likely to meet the first two criteria – a DS2036 façade noise level of at

least 67.5 dB LA10,18h and an increase from before to after of at least 1 dB(A). However, with one possible exception, none of these properties would receive sufficient contribution from the Proposed Scheme to the relevant noise level. Consequently, it is considered unlikely that more than a single dwelling would qualify for insulation under the terms of the NIR. 7.6.94. The possible exception is any permanent residential accommodation associated with the Windhover PH located at the western end of Brampton Lane. Depending on the location of any habitable room windows and the definition of the Proposed Scheme and its contribution to the relevant noise level, it is possible that this property may qualify for treatment under the terms of the NIR.

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SUMMARY OF LIKELY RESIDUAL SIGNIFICANT EFFECTS 7.6.95. As no secondary mitigation is proposed and it is considered likely that, at most, a single dwelling would qualify for insulation under the terms of the NIR, the significant effects remain as identified in the section commencing at paragraph 7.6.80. CUMULATIVE EFFECTS Cumulative Effects 7.6.96. No intra-project cumulative effects are anticipated that involve noise and vibration and the receptors considered in this chapter, but see Chapter 7: Biodiversity (Volume II of the ES) for effects of noise and vibration on fauna and Chapter 14: People and Communities (Volume II of the ES) for effects of noise and vibration on human health. Combination Effects 7.6.97. The assessment is based on a Do-Something scenario that includes the effect of the Proposed Scheme and all cumulative schemes, including Dallington Grange. The effects of these schemes are not included within the ‘Do-Minimum’ scenarios. Therefore, the effects reported above represent a cumulative assessment. MONITORING 7.6.98. The need to undertake compliance noise and vibration monitoring during the construction phase will be determined during the process to compile the CEMP and will require the Contractor to consult with the Environmental Health Officer at Northampton Borough Council and Daventry District Council. 7.6.99. The assessment reported in this chapter identifies that there is potential for significant adverse operational effects to arise as a result of the Proposed Scheme. Consequently, it is proposed to monitor operational road traffic noise levels in the vicinity Proposed Scheme. 7.6.100. The monitoring regime would be discussed and agreed in advance with the highway’s authority (Northampton County Council), but is likely to include:  Road traffic noise measurements to be undertaken at a sample number of receptors (up to a maximum of four) at locations where potentially significant adverse effects have been identified.  Noise measurements to be undertaken for a period of between one-two weeks on two separate occasions – once in the 12-month period before scheme opening and again in the 12-month period after scheme opening; both surveys should occur in the same month (avoiding public holidays) to minimise seasonal variations.  All measurements to be undertaken using appropriately calibrated Class 1 instrumentation and under weather conditions suitable for environmental noise monitoring (predominantly dry with low wind speeds).

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7.7 REFERENCES  Ref. 7-1: Design Manual for Roads and Bridges (DMRB) Volume 11, Section 3, Part 7, LA 111 Noise and Vibration. Highways England, Transport Scotland, Welsh Government, Department for Infrastructure, Revision 2, May 2020  Ref. 7-2: https://www.google.co.uk/maps  Ref. 7-3: TRL Limited, Project Report PR/SE/451/02, Converting the UK Traffic Noise Index

LA10,18h to EU Noise Indices for Noise Mapping, P G Abbott and P M Nelson (TRL Limited), 2002  Ref. 7-4: Noise Insulation Regulations (NIR), 1975 (as amended)  Ref. 7-5: Environmental Noise Directive 2002/49/EC and Environmental Noise (England) Regulations 2006 (as amended)  Ref. 7-6: The Control of Pollution Act (CoPA), 1974  Ref. 7-7: European Commission (2014) Environmental Impact Assessment Directive (EIA) 2014/52/EU  Ref. 7-8: Noise Policy Statement for England (NPSE), 2010  Ref. 7-9: National Planning Policy Framework (NPPF), 2019  Ref. 7-10: Planning Practice Guidance, 2019 (https://www.gov.uk/guidance/noise--2)  Ref. 7-11: Calculation of Road Traffic Noise (CRTN). Department of Transport and Welsh Office. 1988  Ref. 7-12: British Standard 5228 Code of practice for noise and vibration control on construction and open sites. Part 1: Noise. BS 5228:2009+A1:2014. 2014  Ref. 7-13: British Standard 5228 Code of practice for noise and vibration control on construction and open sites. Part 2: Vibration. BS 5228:2009+A1:2014. 2014  Ref. 7-14: Guidelines for Community Noise. World Health Organisation. 1999  Ref. 7-15: Night Noise Guidelines for Europe. World Health Organisation, 2009  Ref. 7-16: https://www.wunderground.com/

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8 ROAD DRAINAGE AND THE WATER ENVIRONMENT

8.1 INTRODUCTION 8.1.1. This chapter and its associated technical appendices supersede the Road Drainage and Water Environment chapter submitted in the 2019 Environmental Statement (ES). Since that time the following changes have occurred:  the traffic model for the Proposed Scheme and traffic volumes have been revisited;  the proposed flood mitigation measures have been developed following improved understanding of the ground conditions within the site;  the Design Manual for Roads and Bridges (DMRB) has been updated. The previous assessment was carried out in accordance with Volume 11, Section 3, Part 10 (HD 45/09) (Ref. 8-1). This document has been replaced with LA 113 (Ref. 8-20) and the methodology set out in this document and subsequent analysis have been updated to reflect this. 8.1.2. To appropriately and coherently address these changes a full update to the Road Drainage and Water Environment Assessment has been completed as part of the Environmental Statement Addendum (ESA). 8.1.3. This chapter provides an assessment of the potential hydrological and hydrogeological effects that the Proposed Scheme may have on the surrounding area and assesses the potential implications of any such hydrological and hydrogeological effects on the Proposed Scheme. This is in accordance with the principles set out in the DMRB LA 113 (Ref. 8-20). 8.1.4. The aspects of the water environment considered within this chapter include the chemical, ecological and hydromorphological quality of surface water features; the chemical quality of groundwater features; groundwater hydrodynamics; and flood risk. 8.1.5. The chapter describes:  the assessment methodology;  the baseline conditions at the Site and in the surrounding area;  the embedded mitigation incorporated into the design of the Proposed Scheme;  a summary of the likely significant effects; and  further mitigation measures proposed to avoid, prevent, reduce or, if possible, offset any residual significant adverse effects, and the likely residual effects after these measures have been employed. 8.1.6. The assessment has been conducted in accordance with relevant legislation, planning policy, guidance and the recommended approach as discussed with the Environment Agency and Northamptonshire County Council (NCC). 8.1.7. This chapter is intended to be read as part of the wider 2019 ES and the ESA. A standalone Water Framework Directive (WFD) Assessment (Appendix 3.10: Water Framework Directive Assessment (Volume III of the ESA)), Drainage Network Water Quality Assessment (Appendix 8.2: Drainage Network Water Quality Assessment (Volume III of the ESA)) and Flood Risk Assessment (FRA) (Appendix 8.1: Flood Risk Assessment (Volume III of the ESA)) are included as technical appendices to this chapter.

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8.1.8. Impacts to ecology, including sensitive and/or important aquatic species and habitats are discussed in Chapter 7: Biodiversity (Volume II of the 2019 ES), although consideration is given to the supporting quality elements of surface water features within this chapter and Appendix 3.10: Water Framework Directive Assessment (Volume III of the ESA). 8.1.9. A detailed description of the Proposed Scheme is provided within Chapter 3: Description of the Proposed Scheme (Volume II of the 2019) and design changes are provided within Chapter 2: Changes to the Description of the Proposed Scheme (Volume II of the ESA). Key aspects of the Proposed Scheme that are of relevance to this chapter include:  Highway embankments: Engineering works for new highway embankments to support the road alignment.  Borrow pits: Material for the highway embankment will be sourced where possible from three large borrow pits to the south of the Rugby to Milton Keynes railway line. Excavation from the proposed flood storage replacement area (see below) is also proposed to be utilised;  River Nene crossing: A new pre-cast bridge crossing the Brampton Branch of the River Nene (20m wide with soffit level of 68.72m AOD). Abutments set back from bank top on each bank, sheet pile bank protection will result in a permanent loss of bankside vegetation, natural bed to remain following construction;  Brampton Brook culvert: Arch bridge style crossing of the Brampton Brook (52m long, minimum 2.8m high and 7m wide). Abutments set back from bank top on each bank, sheet pile bank protection will result in a permanent loss of bankside vegetation, natural bed to remain following construction;  Railway overbridge: A railway overbridge which carries the proposed highway over the Rugby to Milton Keynes railway line;  Surface water drainage system: A new system of gullies discharging to carrier/filter drains and new on-line highway balancing ponds that in turn discharge to the River Nene and its tributaries via three new outfalls;  Flood storage replacement areas: A large flood compensation basin adjacent to the Rugby to Milton Keynes railway line to the east of the Proposed Scheme and a small flood compensation basin adjacent to the golf course to the west of the Proposed Scheme;  Flood mitigation bund: An earth embankment bisecting the right bank floodplain downstream of the Proposed Scheme;  Watercourse diversion: A diversion of a groundwater fed channel towards the River Nene away from the flood mitigation bund.  Two large flood relief culverts beneath the Main Carriageway;  Two large flood relief culverts underneath the Causeway; and  One new surface water culvert and one new surface water pipe beneath the Main Carriageway. 8.2 SCOPE, ASSUMPTIONS AND LIMITATIONS CONSULTATION 8.2.1. Consultation has been undertaken with the Environment Agency throughout the assessment process. Feedback through this consultation was predominantly associated with flood risk management. As such full details of the consultation are provided within Appendix 8.1: Flood Risk Assessment (Volume III of the ESA).

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SCOPE OF THE ASSESSMENT 8.2.2. An EIA Scoping Report was submitted to Northamptonshire County Council in August 2018, please refer to Appendix 5.3: EIA Scoping Report (Volume III of the 2019 ES). In addition, an EIA Scoping Addendum Report was submitted in April 2020, please refer to Appendix 3.6: EIA Scoping Addendum Report (Volume III of the ESA). This section summarises the scope of the assessment. Scoped In 8.2.3. The aspects of the water environment scoped into this assessment include impacts to:  The chemical, ecological and hydromorphological status of surface water features such as watercourses and ponds.  Surface water abstractions that could be affected by changes to flow or water quality.  Groundwater quality and groundwater features that could be affected by surface-borne pollutants, such as Source Protection Zones and groundwater abstractions.  Groundwater receptors and aquifer resources could be affected by below ground structures or excavation.  Potential lowering of groundwater levels due to dewatering during construction.  Flood risk to the Proposed Scheme and elsewhere as a result of the Proposed Scheme. Scoped Out 8.2.4. The following effects have been scoped out because they are considered insignificant and therefore have not been considered further in this assessment:  Reduced groundwater recharge due to the introduction of new impermeable road surfacing/hardstanding. This is considered insignificant due to the small surface area of the proposed alignment compared to the overall catchment.  Impacts to groundwater quality associated with routine road runoff as the underlying geology does not support infiltration. LIMITATIONS AND ASSUMPTIONS 8.2.5. The highway balancing ponds are proposed to be lined, therefore there is a significantly reduced risk for groundwater to be polluted from infiltration of highway runoff and the method outlined in Appendix C of the DMRB LA 113 was not undertaken. Similarly, no assessment has been made to the surface water ditch receiving outflow from basin 2 and outfall 3 that is likely to have a Q95 flow of less than 1 l/s. The geology of the area comprises predominantly Alluvium (thickness estimated to be between 2.5 and 5.3m thick) which is underlain by the Whitby Mudstone Formation (total thickness not proven in GI). Based on geological descriptions these deposits are characterised as relatively low permeability deposits that will not accommodate much infiltration to ground. 8.2.6. The assessment of impacts from below ground structures on groundwater levels is limited to the currently available groundwater level information (Ground Investigation 2020, Ref. 8-22). Further ground investigation will be undertaken during subsequent design stages to confirm local geological conditions and the variation of groundwater levels at the specific location of the borrow pits and the flood storage replacement area. It is also assumed the groundwater dependent terrestrial ecosystems (GWDTEs) are groundwater fed based on the groundwater environment, the presence of springs in the area and the presence of lowland fen habitat.

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8.2.7. The assessment of potential effects on the water environment and flood risk has been informed by information obtained from desk-based sources and information regarding the Proposed Scheme layout available at the time of assessment. No site visit, on-site survey or monitoring has been undertaken to inform this assessment. 8.2.8. It has not yet been possible to identify the location of all outfalls that serve the wider road network connected to the Proposed Scheme. Assumptions have therefore been made using professional judgement and review of adjacent features that are deemed likely to receive runoff. A more detailed description of the existing surface water drainage system and assumptions that have been made regarding existing drainage and outfall locations are located within the Drainage Strategy detailed within Appendix 8.1: Flood Risk Assessment (Volume III of the ESA). 8.2.1. No surface water sampling of the River Nene has been undertaken to inform this assessment. This is not expected to influence the findings of this assessment. 8.3 METHODOLOGY LEGISLATIVE FRAMEWORK 8.3.1. The coordination of policies for the water environment is managed by the UK Government. Many flood risk and water quality requirements are set at European level, which are then transposed into UK law. The Environment Agency has a strategic overview regarding the management of the water environment and all of the sources of flooding and an operational responsibility for managing the risk of flooding from main rivers, reservoirs, estuaries and tidal sources. Lead Local Flood Authorities (in this case NCC) are responsible for managing the risk of flooding from local sources, comprising surface water, groundwater and ordinary watercourses. European Legislation Water Framework Directive (2000/60/EC) 8.3.2. The overall objective of the WFD is to bring about the effective co-ordination of water environment policy and regulation across Europe. The main aims of the legislation are to ensure that all surface water and groundwater reaches ‘good’ status (in terms of ecological and chemical quality and water quantity, as appropriate), promote sustainable water use, reduce pollution and contribute to the mitigation of flood and droughts. 8.3.3. The WFD also contains provisions for controlling discharges of dangerous substances to surface waters and groundwater and includes a ‘List of Priority Substances’. Various substances are listed as either List I or List II substances, with List I substances considered the most harmful to human health and the aquatic environment. The purpose of the directive is to eliminate pollution from List I substances and reduce pollution from List II substances. Groundwater Directive (2006/118/EC) 8.3.4. The Groundwater Directive aims to set groundwater quality standards and introduce measures to prevent or limit pollution of groundwater, including those listed within the ‘List of Priority Substances’. The Directive has been developed in response to the requirements of Article 17 of the WFD, specifically the assessment of the chemical status of groundwater and objectives to achieve ‘good’ status.

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National Legislation Environmental Permitting (England and Wales) Regulations 2010 8.3.5. The Environmental Permitting (England and Wales) Regulations 2010 replaced the Water Resources Act 1991 as the key legislation for water pollution in the UK. Under the Regulations, it is an offence to cause or knowingly permit a water discharge activity, including the discharge of polluting materials to freshwater, coastal waters, relevant territorial waters or groundwater, unless complying with an exemption or an environmental permit obtained from the Environment Agency. The Environment Agency sets conditions which may control volumes and concentrations of particular substances or impose broader controls on the nature of the effluent, taking into account any relevant water quality standards from EC Directives. 8.3.6. The Regulations also regulate works that have the potential to affect a watercourse under the jurisdiction of the Environment Agency. Any works in, under or near a main river requires permission from the Environment Agency to ensure no detrimental impacts on the watercourse. Previously, this was a Flood Defence Consent; however, in April 2016 consent for flood risk activities was included under the Environmental Permitting (England and Wales) Regulations 2010. PLANNING POLICY 8.3.7. Relevant planning policy is discussed in detail in the Supporting Planning Statement (Ref. 8-2). This includes details of the following:  National Planning Policy Framework (NPPF);  Planning Practice Guidance; and  West Northamptonshire Joint Core Strategy Local Plan (Part 1) (2014 - 2029). GUIDANCE AND STRATEGY DOCUMENTS Local Standards and Guidance for Surface Water Drainage in Northamptonshire (2017) (Ref. 8-3) 8.3.8. These guidelines are intended to assist developers in the design of surface water drainage systems, alongside supporting Local Planning Authorities in considering drainage proposals for new developments within Northamptonshire. The guidance highlights where there is divergence from national guidelines such as the DMRB and the Non-Statutory Technical Standards for Sustainable Drainage Systems, see below. Environment Agency Groundwater Protection Guides (2018) (Ref. 8-4) 8.3.9. The groundwater protection guides (Ref. 8-4) set out the framework for Environment Agency regulation and replaces Groundwater Protection: Principles and Practice GP3. Section C Infrastructure of the Environment Agency’s approach to groundwater protection guidance document is of key importance to transport proposals and sets out position statements and the approach to managing and protecting groundwater in relation to infrastructure developments. Pollution Prevention Guidelines 8.3.10. The Pollution Prevention Guidelines issued by the Environment Agency have now been withdrawn, although a number of these guidelines are still considered relevant to design and construction of the Proposed Scheme.

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8.3.11. In particular, Pollution Prevention Guideline 1 provides practical advice on site drainage, Pollution Prevention Guideline 5 provides guidance for works in, near, or liable to affect watercourses, and Pollution Prevention Guideline 6 provides guidance on the control of water pollution during construction and demolition stages of works. Compliance with these Pollution Prevention Guidelines should be considered as part of the environmental management documentation developed for construction and operational phases of the Proposed Scheme. Design Manual for Roads and Bridges (DMRB) 8.3.12. The assessment has been undertaken in accordance with the principles of the methodology promoted within DMRB LA 113. DMRB LA 113 sets out the recommended approach to the assessment of road schemes on the water environment and provides a framework for assessing risks associated with polluted surface water runoff, accidental spillages and flood risk, and provides guidance on mitigation to manage these risks. Non-Statutory Technical Standards for Sustainable Drainage Systems (2015) (Ref. 8-5) 8.3.13. The Non-Statutory Technical Standards for Sustainable Drainage Systems, published by Department for Environment, Food and Rural Affairs (Defra) sets out the core technical standards for SuDS proposed within England. These standards should be used in accordance with the NPPF and Planning Practice Guidance. The standards include guidance on controlling flood risk within a development boundary and elsewhere, peak flow and runoff volume control, and the structural integrity of SuDS. The Construction Industry Research and Information Association (CIRIA) 8.3.14. CIRIA has published several key guidance documents of relevance to the Proposed Scheme, notably C532 (Control of water pollution from construction sites) (Ref. 8-6), C648 (Control of water pollution from linear construction projects) (Ref. 8-7), C750 (Groundwater control, design and practice) (Ref. 8-8) and C753 (The SuDS Manual) (Ref. 8-9) 8.3.15. These documents provide guidance on sustainable drainage systems, pollution control and groundwater control as part of temporary works for construction projects. STUDY AREA 8.3.16. The spatial scope of this assessment has been informed by consideration of the features that may have the potential to be affected by the Proposed Scheme, taking topography, the scale of the works and potential impacts into account. 8.3.17. The study area encompasses surface water features up to a maximum of 500m from the Proposed Scheme that have the potential to be affected directly by the proposed works (i.e. associated with overland migration of pollutants directly to a surface feature). The study area also includes surface water features that are in hydraulic connectivity with the study area, such as those downstream of features that are within 500m of the Proposed Scheme, and that may therefore be affected by indirect impacts (i.e. associated with pollutants that may be conveyed downstream via surface water features or drainage systems). The extent of the study area for indirect effects is more dependent on the sensitivity of the feature and the likely magnitude of impact, but a distance of approximately 1km from the Proposed Scheme is considered appropriate.

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8.3.18. The study area encompasses groundwater resources up to 1km from the Proposed Scheme and specific features such as groundwater abstractions up to 500m from the Proposed Scheme. These distances are considered appropriate for the assessment of surface-borne pollutants migrating to groundwater features. 8.3.19. The study area for the assessment of flood risk is defined by the extent by which flood risk may be influenced and the extent of the relevant flood zones. For an infrastructure project such as this, it is unlikely that upstream flood risks will extend further than 1km from the Proposed Scheme. Downstream flood risks can extend much further, although the requirements of the NPPF to have no impact elsewhere will constrain the extent of impacts. Full details of the extent of the influence of the Proposed Scheme on flood risk are detailed in Appendix 8-1: Flood Risk Assessment (Volume III of the ESA). 8.3.20. Where the assessment indicates an increased risk at a distance further than c.1km from the Proposed Scheme, the study area has been extended accordingly. 8.3.21. Figure 8-1 (Volume IV of the ESA) shows the spatial scope of the study, reflecting an area within 1km of the Proposed Scheme, and the local watercourses within this area. METHOD OF BASELINE DATA COLLECTION Desk study 8.3.22. Baseline information to inform the desk study has been obtained from the following sources:  Environment Agency’s online maps for flood risk (Ref. 8-10);  Environment Agency’s Catchment Data Explorer (Ref. 8-11) (accessed May 2020);  Environment Agency’s Online Flood Map for Planning (Ref. 8-12) (accessed May 2020);  Ordnance Survey (OS) mapping (accessed June 2018) (Ref. 8-16);  British Geological Society (BGS) Geology of Britain viewer (Ref. 8-13) (accessed November 2018);  Consultation with the Environment Agency and Northamptonshire County Council;  Upper Nene Model Report (Ref. 8-14) (September 2013);  Envirocheck report (January 2019) (Ref. 8-23);  Results of the ground investigations undertaken by WSP in May 2018 and January 2019 (Ref. 8- 22);  Geological Survey 1:50,000 Sheet 185 “Northampton” Solid and Drift Edition (1990) (Ref. 8-15);  Defra Magic Map Application (including Aquifer Designation and Groundwater Vulnerability Edition (1990)) (Ref. 8-16)  BGS Geoindex Webtool (accessed May 2019) (Ref. 8-17); and  The Physical Properties of the Minor Aquifers in England and Wales. Hydrogeology Group Technical Report WD/00/04 Environment Agency R&D Publication BGS 2000 (Ref. 8-18). 8.3.23. A detailed hydraulic model has also been developed as part of the FRA, Appendix 8.1: Flood Risk Assessment (Volume III of the ES), and the data derived from this model has been incorporated into the assessment. ASSESSMENT METHODOLOGY 8.3.24. The methodology adopted is based on the principles set out in DMRB LA 113 (Ref. 8-20) and DMRB LA 104 (Ref. 8-21). The assessment of potential effects as a result of the Proposed Scheme has taken into account both the construction and operational phases.

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8.3.25. Based on the principles set out in DMRB LA 113, the following approach has been adopted:  Estimation of the importance of the attribute;  Estimation of the magnitude of the impact; and  Assessment of the significance of the effect based on the importance of the attribute and magnitude of the impact. 8.3.26. The estimation of the magnitude of the impact is mostly qualitative and based on professional judgement. The assessment is supported by a series of technical appendices the provide the justification for the assessment. These are the Water Framework Directive (WFD) Assessment (Appendix 15.1: Water Framework Directive Assessment (Volume III of the ESA)), Drainage Network Water Quality Assessment (Appendix 15.2: Drainage Network Water Quality Assessment (Volume III of the ESA)) and Flood Risk Assessment (FRA) (Appendix 15.3: Flood Risk Assessment (Volume III of the ESA)). Significance Criteria 8.3.27. The significance of identified effects has been assessed based on the magnitude of impact due to the Proposed Scheme and the importance of the affected receptor. The importance of the affected receptor is assessed on a scale of very high, high, medium and low, and the magnitude of impact is assessed as beneficial or adverse on a scale of major, moderate, minor and negligible. Guidance for estimating these factors, taken from DMRB LA 113, is provided in Table 8-1 and Table 8-2. Table 8-1: Estimating the Importance of Water Environment Attributes

Importance Criteria Type Example

Very High Nationally Surface water Watercourse having a WFD classification shown in a significant River Basin Management Plan (RBMP) and a Q95 attribute of ≥1m3/s. high Site protected / designated under European Commission importance (EC) or UK Legislation (Special Area of Conservation, Special Protection Area, Site of Special Scientific Interest, Ramsar site, salmonid water) / species protected by EC legislation.

Groundwater Principal aquifer providing a regionally important resource and / or supporting a site protected under EC and UK legislation. Groundwater locally supports a groundwater dependent terrestrial ecosystem (GWDTE). Source protection zone (SPZ) 1.

Flood risk Essential infrastructure or highly vulnerable development.

High Locally Surface water Watercourse having a WFD classification shown in a significant RBMP and Q95 <1 m3/s. attribute of Species protected under EC or UK legislation. high importance Groundwater Principal aquifer providing locally important resource or supporting a river ecosystem. Groundwater supports a GWDTE. SPZ 2

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Importance Criteria Type Example

Flood risk More vulnerable development.

Medium Of moderate Surface water Watercourse not having a WFD classification shown in a quality and RBMP and Q95>0.001m3/s. rarity Groundwater Aquifer providing water for agricultural or industrial use with limited connection to surface water. SPZ3.

Flood risk Less vulnerable development.

Low Lower quality Surface water Watercourse not having a WFD classification shown in a RBMP and Q95 < 0.0001m3/s.

Groundwater Unproductive strata.

Flood risk Water compatible development

Table 8-2: Estimating the Magnitude of an Impact

Magnitude Criteria Type Example

Major Results in loss Surface water Failure of both acute-soluble and chronic-sediment related Adverse of attribute and pollutants in HEWRAT and compliance failure with EQS / or quality and values. integrity of the Calculated risk of pollution from a spillage ≥2% annually attribute Loss or extensive change to a fishery. Loss of regionally important public water supply. Loss or extensive change to a designated nature conservation site. Reduction in water body WFD classification.

Groundwater Loss of, or extensive change to, an aquifer. Loss of regionally important water supply Potential high risk of pollution to groundwater from routine runoff – risk score >250 Calculated risk of pollution from spillages ≥2% annually Loss of, or extensive change to GWDTE or baseflow contribution to protected surface water bodies. Reduction in water body WFD classification. Loss or significant damage to major structures through subsidence or similar effects.

Flood risk Increase in peak flood level (>100mm)

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Magnitude Criteria Type Example

Moderate Results in Surface water Failure of both acute-soluble and chronic-sediment related Adverse effect on pollutants in HEWRAT but compliance with EQS values. integrity of Calculated risk of pollution from spillages >1% annually attribute, or and <2% annually. loss of part of Partial loss in the productivity of a fishery. attribute Degradation of regionally important public water supply or loss of major commercial / industrial / agricultural supplies. Contribution to reduction in water body WFD classification.

Groundwater Partial loss or change to an aquifer. Degradation of regionally important public water supply or loss of significant commercial / industrial / agricultural supplies. Potential medium risk of pollution to groundwater from routine runoff – risk score 150-250. Calculated risk of pollution from spillages ≥1% annually and <2% annually. Partial loss of the integrity of GWDTE. Contribution to reduction in water body WFD classification. Damage to major structures through subsidence or similar effects or loss of minor structures.

Flood risk Increase in peak flood level (> 50mm).

Minor Results in Surface water Failure of either acute-soluble or chronic sediment related Adverse some pollutants in HEWRAT. measurable Calculated risk of pollution from spillages ≥0.5% annually change in and <1% annually. attributes Minor effects on water supplies. quality or vulnerability Groundwater Potential low risk of pollution to groundwater from routine runoff – risk score <150. Calculated risk of pollution from spillages ≥0.5% annually and <1% annually. Minor effects on an aquifer, GWDTEs, abstractions and structures.

Flood risk Increase in peak flood level (> 10mm).

Negligible Results in Surface water The Proposed Scheme is unlikely to affect the integrity of effect on the water environment. attribute, but of No risk identified by HEWRAT (Pass both acute-soluble insufficient and chronic-sediment related pollutants). magnitude to Risk of pollution from spillages <0.5%.

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Magnitude Criteria Type Example

affect the use Groundwater No measurable impact upon an aquifer and / or of integrity groundwater receptors and risk of pollution from spillages <0.5%.

Flood risk Negligible change to peak flood level (< +/- 10mm).

Minor Results in Surface water HEWRAT assessment of either acute-soluble or chronic- Beneficial some beneficial sediment relevant pollutants becomes Pass from an effect on existing site where the baseline was a Fail condition. attribute or a Calculated reduction in existing spillage risk by 50% or reduced risk of more (when existing spillage risk <1% annually). negative effect occurring Groundwater Calculated reduction in existing spillage risk by 50% or more to an aquifer (when existing spillage risk <1% annually). Reduction in waterlogging and groundwater flooding.

Flood risk Creation of flood storage and decrease in peak flood level (>10mm).

Moderate Results in Surface water HEWRAT assessment of both acute-soluble and chronic- Beneficial moderate sediment relevant pollutants becomes Pass from an improvement of existing site where the baseline was a Fail condition. attribute quality Calculated reduction in existing spillage risk by 50% or more (when existing spillage risk >1% annually). Contribution to improvement in water body WFD classification.

Groundwater Calculated reduction in existing spillage risk by 50% or more (when existing spillage risk >1% annually). Contribution to improvement in water body WFD classification. Improvement in water body Catchment Abstraction Management Strategy (CAMS) (or equivalent) classification. Support to significant improvements in damaged GWDTEs.

Flood risk Creation of flood storage and decrease in peak flood level (>50mm).

Major Results in Surface water Removal of existing polluting discharge or removing the Beneficial major likelihood of polluting discharges occurring to a improvement watercourse. of attribute Improvement in water body WFD classification. quality Groundwater Removal of existing polluting discharge to an aquifer or removing the likelihood of polluting discharges occurring. Improvement in water body WFD classification. Recharge of an aquifer.

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Magnitude Criteria Type Example

Flood risk Creation of flood storage and decrease in peak flood level (>100mm).

No change No loss or alteration of characteristics, features or elements; no observable impact in either direction.

8.3.28. Table 8-1 provides the guidance for estimating the significance of the potential effects for the construction and operation phases of the Proposed Scheme. This assessment of significance is derived from DMRB LA 104 (Ref. 8-21). Where there is a choice of significance score, professional judgement has been used in the selection of the final score. 8.3.29. Anything classified as having moderate or above effects in Table 8-3 is considered to be significant and will require mitigation in accordance with DMRB LA 104 (Ref. 8-21).

Table 8-3: Estimating the Significance of Potential Effects

Magnitude of Impact

No Change Negligible Minor Moderate Major

Importance Very High Moderate or Large or Neutral Slight Very Large of Attribute Large Very Large

High Slight or Moderate or Large or Neutral Slight Moderate Large Very Large

Medium Neutral or Moderate or Neutral Slight Moderate Slight Large

Low Neutral or Neutral or Slight or Neutral Slight Slight Slight Moderate

Negligible Neutral or Neutral or Neutral Neutral Slight Slight Slight

8.4 BASELINE CONDITIONS EXISTING BASELINE 8.4.1. This section provides a description of the current baseline conditions with respect to the water environment. Site Description and Topography 8.4.2. A detailed description of the site and surrounding topography can be found in Chapter 2: The Existing Site (Volume II of the 2019 ES). A full description of the Proposed Scheme is included in Chapter 3: Description of the Proposed Scheme (Volume II of the ESA) and Chapter 2: Changes to the Description of the Proposed Scheme (Volume II of the ESA).

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River Nene 8.4.3. The Brampton Branch of the River Nene (hereafter referred to as the River Nene) flows to the east of the Proposed Scheme. The River Nene is a Main River under the jurisdiction of the Environment Agency. It flows in a southerly direction to its confluence with the larger arm of River Nene approximately 4.3km downstream of the study area. The River Nene then continues to flow in an easterly direction to the south of Northampton. 8.4.4. At the location of the Proposed Scheme, the River Nene is located within the Anglian River Basin District in the Brampton Branch - Lower catchment. This reach of the River Nene is referred to as the Brampton Branch of the River Nene in the WFD data. 8.4.5. The River Nene flows in an approximately north to south direction from its source at Arbury Hill, Northamptonshire, from a maximum elevation of 206m AOD draining a catchment area of 233 km2. Two unnamed tributaries of the main Nene branch are impounded by large reservoirs – Ravensthorpe, and Pitsford, the latter being the most significant. A third, unnamed tributary joins the Nene upstream of the Proposed Scheme. The Brampton Brook (discussed below) joins the Nene in the vicinity of the Proposed Scheme at SP 73478 64426. Catchment landcover is comprised predominantly of arable farmland and grassland (54% and 29% respectively) with small parcels of woodland (9%) and urban extent (8%) occupying the remainder. 8.4.6. The river system has been extensively modified from its original form (likely a slow anastomosing system) to a largely single-thread, over-deep channel. The banks of the river are comprised of cohesive clays and non-cohesive alluvial gravels, whose sheer bank faces are indicative of channel incision owing its considerably modified condition. The channel substrate is comprised predominantly of fine to medium gravels mixed with significant silt and sand deposits originating from the local banks and surrounding agricultural land. 8.4.7. There is some sign of morphological recovery within the over-deep channel corridor, as evidenced by alternating sediment berm deposits that provide localised riparian habitat; however, the riparian corridor is, for the most part, low quality. Flow dynamics within the River Nene are typical of a modified lowland river, with long, homogenous glide sections and pools dominating flow structure. The aforementioned berm features serve to narrow the channel intermittently, creating occasional, localised regions of elevated flow velocity. 8.4.8. Thus, the overall morphological functioning of the River Nene is low due to excessive modification of the channel. 8.4.9. Water quality of the River Nene (Brampton Branch – Lower) is monitored against the objectives of the WFD. Cycle 2 (2016) results report that the overall status of the waterbody is assessed to be poor, with current ecological quality assessed to be poor and current chemical quality assessed to be good. The poor ecological rating is stated to be attributed to biological quality elements (macrophytes) and physico-chemical quality elements (phosphate). 8.4.10. There are no statutory ecological designations associated with the River Nene within 1km of the Proposed Scheme. The River Nene may have potential to support otter, with evidence of otter activity in the form of feeding remains, spraints and camera footage recorded along the entire length of the River Nene running parallel to the Proposed Scheme. For further details, refer to Chapter 7: Biodiversity (Volume II of the 2019 ES). 8.4.11. No surface water sampling of the River Nene has been undertaken to inform this assessment.

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Brampton Brook 8.4.12. Brampton Brook flows immediately to the north of the Northampton to Rugby railway line and has a catchment size of 30km2 to its confluence with the River Nene. The watercourse has been impacted by historical activities such as: channel straightening, dredging, local land-use changes and infrastructure development. The present-day character of the brook is indicative of an over-deep channel (around 3m below its floodplain) with very low functioning habitat and natural fluvial processes. The channel substrate is comprised predominantly of fine to medium gravels mixed with significant silt and sand deposits originating from the local banks and surrounding agricultural land. 8.4.13. There is no sign of morphological recovery within the channel corridor; however, an occasional tree offers some, albeit limited, habitat. 8.4.14. The watercourse is a main river in the vicinity of the Proposed Scheme under the jurisdiction of the Environment Agency and flows in an easterly direction to its confluence with the River Nene, located approximately 210m to the east of the Proposed Scheme. It is located within the Anglian River Basin District in the Church Brampton Arm catchment. 8.4.15. Water quality of Brampton Brook is monitored against the objectives of the WFD. Cycle 2 (2016) results report that the overall status of the waterbody is assessed to be moderate, with current ecological quality assessed to be moderate and current chemical quality assessed to be good. The moderate ecological rating is stated to be attributed to biological quality elements (macrophytes and phytobenthos) and physico-chemical quality elements (phosphate). 8.4.16. There are no statutory ecological designations associated with Brampton Brook or within 1km of the Site. 8.4.17. There is evidence of some protected and notable species including otters and kingfishers. For further information, refer to Chapter 7: Biodiversity (Volume II of the 2019 ES). Surface water abstractions and ordinary watercourses 8.4.18. Licensed water abstraction data has been extracted from the Envirocheck report. Table 8-4 details the surface water abstractions in the vicinity of the Proposed Scheme. The location of these features is illustrated in Figure 8-1 (Volume IV of the ESA).

Table 8-4: Licensed water abstractions

Ref Source General location Grid Abstraction Reference

1 Surface 300m north of A5199 on the River 473471 General Agriculture: Spray Nene 265630 Irrigation - Direct

2 Surface 350m north of A5199 on the River 473500 General Agriculture: Spray Nene 265695 Irrigation – Direct

3 Surface 250m east of A5199 and south of 473900 General Agriculture: Spray Brampton Lane on local drain 264900 Irrigation – Storage. Impounding.

4 Surface 400m east of A5199 and south of 474060 General Agriculture: Spray Brampton Lane on local drain 264945 Irrigation – Direct or Storage.

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Ref Source General location Grid Abstraction Reference

5 Stream Confluence of River Nene and 473500 Spray Irrigation. Brampton Brook 264300

6 Surface Brampton Brook 700m upstream of 472750 Golf Courses: Spray Irrigation - confluence 264280 Storage

7 Surface Brampton Brook 700m upstream of 472700 Golf Courses: Spray Irrigation - confluence 264200 Storage

8.4.19. There are a number of ordinary watercourses scattered about the site that are of varying importance and interest, shown on Figure 8-1 (Volume IV of the ESA). To the north of Brampton Brook are two surface water drains running west to east draining the golf course. The ditches are ephemeral and as such do not support notable aquatic species, however they do provide a habitat corridor for some mammals refer to Chapter 7: Biodiversity (Volume II of the 2019 ES). 8.4.20. Adjacent to the northern of these two ditches there are a couple of meanders off the River Nene. The habitat here was noted to be suitable for otters and amphibians in September 2018 although no evidence of either was identified. Follow up surveys in April and May 2019 also found no evidence. 8.4.21. Three Groundwater Dependent Terrestrial Ecosystems (GWDTEs) (Lowland Fens Priority Habitats) have been identified within the study area, shown on Figure 8-1 (Volume IV of the ESA). The feature to the north of the flood storage replacement area was found to contain negligible aquatic habitat but remains a tree lined corridor for other species such as bats and foxes. Kingsthorpe Ditch was confirmed to be lowland fen with grasses and reeds providing habitat for small numbers of smooth newts. The final GWDTE is on the right bank of Brampton Brook downstream of the Proposed Scheme. Further details are provided in Chapter 7: Biodiversity (Volume II of the 2019 ES). Geology 8.4.22. A detailed description of the underlying geology is provided in Chapter 10: Geology and Soils (Volume II of the 2019 ES). A summary is provided here with focus on the hydrogeological conditions. 8.4.23. A review of the BGS Geoindex Webtool (Ref. 8-18) 1: 50,000 data indicates that the solid geology comprises the Northampton Sand Formation and the Whitby Mudstone Formation. The Northampton Sand Formation (sandstone including lenses of mudstone and limestone) underlies the Site in the area occupied by the golf courses to the west and in the surroundings of Grange Farm in the southern part of Site. The Whitby Mudstone Formation underlies the majority of the Proposed Scheme within the river valley where erosion has removed the overlying sandstone and typically comprises mudstone, siltstone and rare calcareous sandstone beds. 8.4.24. The solid geology deposits are in part overlain by superficial alluvial deposits, comprising clay, silt, sand and gravel, located along the alignment of the River Nene and Brampton Brook. 8.4.25. The ground investigation undertaken by WSP in May 2018 along the preferred route of the Main Carriageway indicated the superficial deposits to be alluvium between 2.5m and 5.3m thick. The alluvium was predominantly described as gravelly clay or clayey gravel with layers of sand also present.

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8.4.26. The ground investigation undertaken by WSP in January 2019 to the north of the Milton Keynes to Rugby railway line in the vicinity of the flood storage replacement area revealed the superficial to be between 1.7m and 4m in thick. These deposits are described as alluvium predominantly composed of sand or sandy clay, becoming more clayey with depth (usually below 2.5m below ground level (BGL)), and often a gravelly layer is encountered at base of the alluvium. 8.4.27. This ground investigation also focussed on the area to the south of the Milton Keynes to Rugby railway line in the vicinity of the borrow pits. Again, alluvium was encountered, ranging between 1m and 5.7m thick, thickest in the southern part of the Proposed Scheme at Borrow Pit 3, please refer to Figure 2-1: General Arrangement Design (Volume IV of the ESA). The composition of the alluvium varied between gravelly sand, gravelly clay, clayey sand or sandy clay occasionally underlain by clayey gravel, below which the weathered bedrock was encountered. 8.4.28. The ground investigations confirmed the bedrock described above, with both the Whitby Mudstone and the Northampton Sand Formations being encountered as weathered bedrock. The mudstone comprised gravelly clay and the sandstone was described as clayey gravel. Hydrogeology 8.4.29. The Northampton Sand Formation is classified by the Environment Agency as a Secondary A Aquifer. The formation is the basal unit of the Inferior Oolite Group and is expected to have a thickness of up to 20m in the Northampton area (Ref. 8-18). The Environment Agency defines Secondary A Aquifers as permeable layers capable of supporting water supplies at a local rather than a strategic scale, and in some cases forming an important source of base flow to rivers. 8.4.30. The superficial deposits are also classified as a Secondary A Aquifer and are likely to allow substantial groundwater flow and provide groundwater storage, as indicated by the high groundwater levels during Ground Investigation works. Historically, several hundred cubic meters per day have been reported to be abstracted from local supplies, although the aquifer no longer provides public or other major supplies in the Northamptonshire area (Ref. 8-18). 8.4.31. The Whitby Mudstone Formation is classified by the Environment Agency as Unproductive Strata. 8.4.32. Review of Defra’s Magic Map (Ref. 8-16) indicates that the Proposed Scheme is not located in a groundwater Source Protection Zone (SPZ). Review of the Envirocheck report (Ref 8-23) indicates no groundwater abstractions recorded on or within 500m of the Site, however both the Northampton Sand Formation and alluvium could be supporting minor private abstractions. 8.4.33. The WFD groundwater body within this area is identified as the Nene Mid Lower Jurassic Unit (SP7733568437). This waterbody is designated as a drinking water protected area and is utilised throughout the catchment for small local, private water supplies. As of Cycle 2 (2016), this groundwater body has good WFD status. 8.4.34. The risk of soil contamination within the study area is considered to be low due to the agricultural use. 8.4.35. Groundwater was encountered in the superficial deposits during the Ground Investigation. In the proposed flood storage replacement area, the groundwater was found to be between 1.4mBGL and 2.9mBGL (Ref. 8-22).

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8.4.36. In the vicinity of the proposed borrow pits, the groundwater level in the superficial deposits was encountered at between 1mBGL and 3mBGL. Groundwater was also encountered in the underlying sandstone at 2.8mBGL and 3.9mBGL in this area (Ref. 8-22). 8.4.37. Monitoring boreholes were installed immediately to the north of the Milton Keynes to Rugby railway line in the vicinity of the flood storage replacement area and to the south of the Milton Keynes to Rugby railway line in Borrow Pit 1 (Shallow and Deep) and Borrow Pit 3 and groundwater level monitoring was undertaken in January, February and May 2019. Additional groundwater level monitoring is currently ongoing for the site. All groundwater levels referenced in this report are representative of monitoring completed to May 2019. 8.4.38. The borehole in the vicinity of the flood storage replacement area was installed with a response zone in the weathered Whitby Mudstone (comprised of gravelly clay) to a depth of 10.2mBGL. The borehole in Borrow Pit 1 was installed with a response zone in the Northampton Sand Formation from 3mBGL - 4mBGL (Shallow) and from 5mBGL - 8mBGL (Deep). The borehole in Borrow Pit 3 was installed in the alluvium from 3-5mBGL. 8.4.39. The monitoring data from the borehole in the vicinity of the flood storage replacement area indicate groundwater levels between 0.95mBGL -1.38mBGL in the Whitby Mudstone Formation. The measured water levels from the deeper installation in Borrow Pit 1 indicate groundwater at approximately 3.7mBGL - 3.9mBGL in the sandstone. The shallower borehole installation in Borrow Pit 1 was dry and did not record groundwater. Groundwater level data from the borehole in Borrow Pit 3 indicate the groundwater level at approximately 1mBGL in the alluvium. 8.4.40. Available groundwater level data are insufficient to describe groundwater flow directions and horizontal and vertical hydraulic gradients. It is considered likely that the superficial deposits and bedrock aquifers are in hydraulic continuity, and groundwater flow direction being generally towards the river. The shallow nature of the groundwater suggests it will be contributing to the river baseflow. 8.4.41. Three GWDTEs have been identified within the study area. These relate to three drainage ditches which are located north of the Milton Keynes to Rugby railway line at the southern extent of the Proposed Scheme and are designated as ‘lowland fen’ in the Habitats of Principal Importance (HPI) database. These are shown in Figure 8-1 (Volume IV of the ESA) and a detailed description of the lowland fen is provided in Chapter 7: Biodiversity (Volume II of the 2019 ES). Existing Drainage Systems 8.4.42. The Proposed Scheme will pass through open countryside and the proposed drainage system will be standalone and will not connect into any existing drainage systems. 8.4.43. For information, public sewers are located along Sandy Lane and within the housing development to the east. There is a foul water pumping station owned by Anglian Water located to the north east of the Proposed Scheme, and two foul sewer pipes run across the north of the Proposed Scheme boundary. There is a raw (untreated clean water) water pipe that runs in a northerly direction to the west of the Site and a raw water pumping station located to the north west of the Site, owned by Anglian Water.

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Flood Risk 8.4.44. Appendix 8.1: Flood Risk Assessment (Volume III of the ESA) contains copies of all flood risk maps relevant to the Proposed Scheme. 8.4.45. A review of the Environment Agency’s Flood Map for Planning (Rivers and Sea) (Ref. 8-12) indicates that land adjacent to the River Nene is located within the high-risk Flood Zone 3. Flood Zone 3 is defined as land with a 1% (1 in 100) or greater annual probability of flooding from fluvial (river) sources. 8.4.46. The northern extent of the Mainline of the Proposed Scheme will be located within the low-risk Flood Zone 1 where the annual probability of fluvial flooding is less than 0.1% (1 in 1000yr). The southern extent of the Mainline of the Proposed Scheme crosses the floodplain of the River Nene approximately 250m west of the confluence with Brampton Brook and so is situated within Flood Zone 3. Similarly, the Causeway and the flood attenuation bund bisects the floodplain of the River Nene and are situated in Flood Zone 3. 8.4.47. The current Flood Zones of these watercourses do not consider the updated climate change recommendations published by the Environment Agency in March 2016. This guidance recommends a 25% to 65% increase in fluvial flood flows to account for the potential effects of climate change over the next 100 years. If climate change is considered, this is will increase the risk of fluvial flooding to the Proposed Scheme. 8.4.48. Discussions with the Environment Agency have highlighted that the existing standard of protection from flooding in Northampton has been designed to the 0.5% (1 in 200) annual probability design standard plus climate change. A letter was issued on the 2nd February 2017 by the Environment Agency setting out their requirements for the study. In this letter, the Environment Agency stated that to maintain this standard, new development in the upstream catchment should also be designed to this standard. This requirement is also presented in the West Northamptonshire Joint Core Strategy (Ref. 8-19). 8.4.49. A review of the Environment Agency’s Risk of Flooding from Surface Water map (Ref. 8-10) indicates a similar flood extent to the fluvial flood risk for both the River Nene and Brampton Brook. The flood mapping also indicates relatively minor overland flow routes that drain towards the River Nene in the vicinity of the Proposed Scheme. Sensitive Receptors The sensitive receptors that have been identified in the vicinity of the Proposed Scheme are listed in

8.4.50. Table 8-. The sensitivity of these receptors can change depending on various features of the receptor, such as water quality, hydromorphology, ecology, flood risk, recreation etc. The predominate reason for the importance of each receptor is summarised in Table 8-5 and is based upon the criteria outlined in Table 8-1.

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Table 8-5: Summary of identified receptors and receptor importance

Receptor Importance Reason

River Nene High Waterbody having a WFD classification shown in the RBMP and having a Q95 of <0.1m3/s.

Brampton Brook High Waterbody having a WFD classification shown in the RBMP and having a Q95 of <0.1m3/s.

Golf course drainage ditches Low Watercourse not having a WFD classification shown in a RBMP and Q95 < 0.0001m3/s.

Superficial deposits aquifer Medium Secondary A Aquifer (with no known groundwater abstraction but potential for local groundwater abstraction)

Northampton Sand Formation Medium Secondary A Aquifer (with no known groundwater aquifer abstraction but potential for local groundwater abstraction).

Groundwater Dependent High Sensitive nature of the biodiversity, as mentioned in Terrestrial Ecosystems Chapter 7: Biodiversity (Volume II of the 2019 ES).

Residential properties and the High More vulnerable development. A5199 upstream of the Causeway

Boughton Mill Equestrian Centre Medium Less vulnerable development riding track and Boughton Mill

Properties and land downstream High More vulnerable development. and within Northampton

FUTURE BASELINE 8.4.51. The most significant change in the baseline conditions without the implementation of the Proposed Scheme is likely to be associated with an increase in peak river flows and peak rainfall intensity associated with the potential effects of climate change. The Environment Agency provides relevant guidance on the range of potential climate change allowances dependent on the relevant river basin district and climate change probability. 8.4.52. The Proposed Scheme is located in the Anglian River Basin District. In this region, it is predicted that by 2115 peak river flows could increase by 25% (central allowance), 35% (higher central allowance) and 65% (upper end allowance). This may increase the frequency of flood risk to identified receptors and increase the extent of Flood Zones 2 and 3, resulting in a greater area of the Site being at risk of flooding and to greater depths. 8.4.53. Additionally, the peak rainfall intensity may also increase as a result of climate change, thereby potentially increasing the risk of surface water flooding to the Site. The Environment Agency provides guidance on the Upper end and Central allowances which cover the whole of England. The total change by 2115 is projected to be 20% and 40% for the central and upper end allowances, respectively.

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8.4.54. There are four committed development sites in the vicinity of the Proposed Scheme. These have the potential to change the local catchment hydrology and hydrogeology. Figure 3.1: Committed Developments (Volume IV of the ESA) shows the location of these developments and more information can be found in Chapter 3: Description of the Proposed Scheme (Volume II of the ESA) and Chapter 2: Changes to the Description of the Proposed Scheme (Volume II of the ESA). It is assumed that all development sites will incorporate an appropriate surface water drainage strategy that has been approved by the Local Planning Authority to best represent the existing baseline situation at the time of construction, and as such will not have a significant effect on flood risk and water quality in a future baseline scenario. 8.5 EFFECTS ARISING DURING CONSTRUCTION PRIMARY MITIGATION MEASURES 8.5.1. The design of the Proposed Scheme has, where possible, been developed to reduce impacts to the water environment. With specific relevance to construction impacts, this has included:  The proposed crossings of the Brampton Brook and the River Nene are clear span structures that will retain a natural riverbed and watercourse alignment.  Abutments for the River Nene bridge crossing will be set back 6m from the channel top-of-bank which will allow greater light below the structure.  Abutments for the Brampton Brook crossing will be set back from the channel bed to allow greater light below the structure.  Diversions of the River Nene and Brampton Brook will not be required. ASSESSMENT OF IMPACTS AND EFFECTS Temporary Effects During Construction Increased sedimentation 8.5.2. Works within close proximity to the River Nene, Brampton Brook and the minor surface water drains could lead to increased sedimentation in surface water runoff. Increased sedimentation in a watercourse can alter the aquatic habitat and smother species and habitats. 8.5.3. The importance of the River Nene is considered to be high. Due to the close proximity of the proposed works to the watercourse and without any control of sediment (i.e. prior to mitigation), overland flow during the construction phase is likely to include elevated sediment levels that could result in an effect on the integrity of certain attributes, specifically smothering bed substrates and affecting physico-chemical water quality parameters. 8.5.4. This may therefore cause a moderate adverse impact to the waterbody. Therefore, there is likely to be a direct and medium-term (up to 2yrs) effect of large significance during the construction phase, which is considered significant. The watercourse is likely to return to baseline conditions after this time as larger flood flows disperse sediment and habitats recover.

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8.5.5. The importance of the Brampton Brook is considered to be high. Without any control of sediment (i.e. prior to mitigation) the increased sedimentation predicted to occur during the construction of the Proposed Scheme, is predicted to cause a moderate adverse magnitude of impact on the waterbody. As per above, the close proximity of the works will likely result in increased sediment in overland flow that could impact both water quality and ecology through smothering of habitat and species, although over time the watercourse will recover to baseline conditions and no permanent effects are likely. Therefore, there is likely to be a direct and medium-term (up to 2yrs) effect of large significance during the construction phase, which is considered significant. 8.5.6. The importance of the golf course drainage ditches is considered to be low. Given the ephemeral nature of these features the increased sedimentation expected from the construction phase, without any control of sediment (i.e. prior to mitigation), is likely to cause a minor adverse to negligible magnitude of impact on the waterbody. The works may result in an effect on certain attributes (most notably smothering of substrates and habitats) but this will be of insufficient magnitude to affect the use or integrity of these features. Therefore, the significance of effect during the construction phase is considered neutral. 8.5.7. Table 8-6 provides a summary of the likely effects associated with increased sedimentation to each receptor identified in the assessment.

Table 8-6: Impacts during construction arising from increased sedimentation

Receptor Comments Magnitude Significance of Impact of Effect

River Works within close proximity to the River Nene could lead to Moderate Large Nene increased sedimentation in surface water runoff. Increased adverse sedimentation in the watercourse can alter the aquatic habitat and smother species and habitats.

Brampton Works within and adjacent to Brampton Brook could lead to Moderate Large Brook increased sedimentation in surface water runoff. Increased adverse sedimentation in the watercourse can alter the aquatic habitat and smother species and habitats.

Golf Works within and adjacent to these surface water drains could Minor Neutral course lead to increased sedimentation in surface water runoff that could adverse to drainage smother the bed substrate, although features are ephemeral and negligible ditches drain runoff from surrounding catchment in baseline scenario.

Pollution risks 8.5.8. Works within close proximity to the River Nene and Brampton Brook could lead to increased pollution in surface water runoff. Increased pollution in a watercourse can alter the aquatic habitat and smother species and habitats. 8.5.9. The importance of the River Nene is high. The impact on water quality associated with the migration or spillage of hydrocarbons and other pollutants from site during construction without any control of polluted runoff (i.e. prior to mitigation) is considered to be minor adverse. A significant spillage could affect chemical and physico-chemical water quality and result in some measurable loss of aquatic species, although the volume of pollutant spillage is unlikely to be high and pollutants will disperse and dilute quickly after a spillage event.

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8.5.10. Therefore, there is likely to be a direct and temporary effect on the River Nene of moderate significance during the construction phase, which is considered significant. 8.5.11. The importance of the Brampton Brook is high. As per above, the magnitude of impact on water quality associated with the migration or spillage of hydrocarbons and other pollutants from site during construction without any control of polluted runoff (i.e. prior to mitigation) is considered to be minor adverse. Therefore, there is likely to be a direct and temporary effect on Brampton Brook of moderate significance during the construction phase, which is considered significant. 8.5.12. Impacts on groundwater from pollution or creation of additional pathways from piling / foundations works could potentially affect the quality of the superficial aquifer (Secondary A Aquifer) and, less likely, the Northampton Sand Formation aquifer (Secondary A Aquifer). The importance of both groundwater resources is medium. 8.5.13. The magnitude of impact on water quality associated with the migration or spillage of hydrocarbons and other pollutants from the site during construction without any control of polluted runoff (i.e. prior to mitigation) is considered to be minor adverse because there is limited potential for runoff to enter the groundwater body due to elevated clay contents of the superficial deposits. Groundwater in the superficial deposits are expected to already be in hydraulic continuity with the bedrock aquifer. Therefore, in the event of a pollution incident, there is likely to be a local and temporary effect on groundwater resources of slight significance during the construction phase, which is considered not significant. 8.5.14. Table 8-7 provides a summary of the likely effects associated with pollution risk to each receptor identified in the assessment.

Table 8-7: Impacts during construction arising from pollution risks

Receptor Comments Magnitude Significance of Impact of Effect

River Nene Works within close proximity to the River Nene could Minor Moderate lead to increased pollution in surface water runoff. adverse Increased pollution in the watercourse can alter the aquatic habitat and smother species and habitats.

Brampton Works within close proximity to the Brampton Brook Minor Moderate Brook could lead to increased pollution in surface water runoff. adverse Increased pollution in the watercourse can alter the aquatic habitat and smother species and habitats.

Groundwater The superficial deposits of alluvium along the alignment Minor Slight resources of the River Nene and Brampton Brook may be adverse susceptible to infiltration of pollutants. Groundwater abstractions are not located in close proximity to the proposed works.

Impacts to the Water Framework Directive status 8.5.15. The WFD monitors the hydromorphological, chemical and ecological quality of watercourses. The impact of the construction phase of the Proposed Scheme on the WFD status of the relevant waterbodies is assessed in a separate WFD assessment (Appendix 3.10: Water Framework Directive Assessment (Volume III of the ESA)).

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8.5.16. In summary, the WFD assessment concludes that the construction phase of the Proposed Scheme is not predicted to cause degradation of the WFD status, nor prevent the relevant water bodies from achieving their WFD objectives. Therefore, the effect to WFD status is considered to be of neutral significance, which is considered not significant. Impacts to Groundwater and GWDTEs 8.5.1. Dewatering of the superficial deposits aquifer (alluvium) may be required for the construction of the flood storage replacement area and borrow pits. This is expected to alter local groundwater levels and groundwater flow directions temporarily. 8.5.2. Further Ground Investigation will be undertaken at the detailed design stage to confirm local groundwater level and geological conditions to establish if dewatering will be required. If Ground Investigation confirms that the excavations extend significantly below groundwater table, a dewatering strategy will need to be developed to manage impacts on groundwater resources. 8.5.3. The importance of the superficial deposits is considered to be medium. The works may result in a measurable localised effect to groundwater flow, but this will be temporary and unlikely to significantly affect local abstractions. The magnitude of impact in the event of required dewatering is therefore expected to be minor adverse. Therefore, there is likely to be a direct and temporary effect on superficial deposits of slight significance during the construction phase, which is considered not significant. 8.5.4. Potential impacts on GWDTEs may arise from construction phase dewatering activities and the construction of the flood mitigation bund. Any changes in the hydrodynamics of the groundwater resources may lead to deterioration of the habitat. Based on the groundwater environment, the presence of springs in the area and the presence of lowland fen habitat it is assumed the GWDTEs are groundwater fed. 8.5.5. The importance of the GWDTEs is therefore presumed to be high due to the sensitive nature of the biodiversity, as mentioned in Chapter 7: Biodiversity (Volume II of the 2019 ES). As discussed above, the works may result in a measurable localised effect to groundwater flow, but this will be temporary and unlikely to cause damage to GWDTEs. 8.5.6. The magnitude of impact on the GWDTEs is considered to be minor adverse. This is due to the distance between the GWDTEs and the proposed flood replacement storage area and railway overbridge and the short reach of GWDTEs affected by the flood mitigation bund. Therefore, the effects from dewatering on GWDTEs during the construction phase are likely to be of slight significance and are closely related to changes of the aquifer conditions described above, which is considered not significant. 8.5.7. Table 8-8 provides a summary of the likely effects associated with pollution risk to each receptor identified in the assessment.

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Table 8-8: Impacts during construction to groundwater resources and GWDTEs

Receptor Comments Magnitude Significance of Impact of Effect

Superficial deposits Dewatering activities, if required, could alter local Minor Slight aquifer groundwater levels and groundwater flow adverse directions temporarily.

Groundwater Dewatering activities, if required, and the Minor Slight Dependent construction of the flood mitigation bund could adverse Terrestrial affect groundwater hydrodynamics that may in Ecosystems turn affect GWDTEs.

Increased flood risk 8.5.8. During the construction phase, there is potential that flood risk is increased due to temporary constrictions to the channel, or through construction of the infrastructure in the floodplain if the compensatory storage is not constructed prior to the embankment. A detailed assessment of the impacts associated with flood risk is provided in Appendix 8-1: Flood Risk Assessment (Volume III of the ESA). 8.5.9. The importance of identified receptors in the vicinity of the Scheme is considered to be high (for a residential property and A5199 upstream and properties and land downstream and within Northampton) or medium (Boughton Mill Equestrian Centre riding track and Boughton Mill). 8.5.10. Prior to the inclusion of mitigation, the works may result in increase in local flood levels upstream and downstream of the Proposed Scheme of greater than 100mm during the 200yr+65% event as there is some risk associated with possible temporary loss of flood storage relating to the embankment being constructed before the flood storage replacement areas. The magnitude of impact is therefore considered to be major adverse. Therefore, there is likely to be a direct and temporary effect on flood risk of large significance to the residential property and A5199 and properties and land downstream and within Northampton, and moderate significance to Boughton Mill Equestrian Centre riding track and Boughton Mill during the construction phase, which is considered significant. 8.5.11. The increase in impermeable surface could also result in an increase in the rate and volume of surface water runoff that is discharged to the River Nene if the Proposed Scheme is constructed without attenuation of runoff. This is likely to only affect downstream receptors. The importance of identified receptors downstream of the scheme is considered to be high. The magnitude of impact prior to mitigation is considered to be minor adverse as flood levels are unlikely to increase by more than 10mm. Therefore, there is likely to be a direct and temporary effect on flood risk of slight significance to properties and land downstream and within Northampton, which is considered not significant. 8.5.12. Table 8-9 provides a summary of the likely effects associated with flood risk to each receptor identified in the assessment.

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Table 8-9: Impacts during construction arising from flood risk

Receptor Comments Magnitude Significance of Impact of Effect

Properties and Increase risk to properties and A5199 upstream is likely Major Large the A5199 to occur during temporary constriction of the adverse upstream of the watercourse or floodplain which prevents transfer of Causeway flood waters downstream.

Boughton Mill Increase risk upstream is likely to occur during Major Moderate Equestrian Centre temporary constriction of the watercourse or floodplain adverse riding track and which prevents transfer of flood waters downstream. Boughton Mill

Properties and Increased flood risk to the town of Northampton, located Major Large land downstream immediately downstream of proposed works in area adverse and within known to be sensitive to flooding. Increased surface Northampton water runoff from impermeable surfaces to properties and land downstream prior to implementation of drainage systems. MITIGATION MEASURES Construction Environmental Management Plan (CEMP) 8.5.13. The main method for controlling impacts during the construction phase of the Proposed Scheme is the adoption and implementation of a Construction Environmental Management Plan (CEMP). An Outline CEMP is submitted in support of the planning application (Appendix 3.1: Outline CEMP (Volume III of the ES)) and incorporates the recommended measures below. A Full CEMP will be developed by the contractor prior to construction commencing and should include measures from the Outline CEMP. 8.5.14. The CEMP would set out how construction activities would be undertaken in accordance with appropriate good practice guidance, such as CIRIA’s Control of Water Pollution from Construction Sites (C532). 8.5.15. Although withdrawn, the Environment Agency’s Pollution Prevention Guidelines discussed in Section 15.3 have been used to inform these recommendations. Key mitigation measures that will be implemented through the CEMP include: Managing sediment entrainment and pollution of watercourses  Avoid the positioning of stockpiles near to watercourses, ensure they are located outside of the flood zone. Stockpiles should be located a minimum of 10m from the top of bank.  Cover stockpiles when not in use.  Contain stockpiles with bunds or sediment fences.  Control of runoff during construction. This may include creating temporary drainage systems to both alleviate flood risk and help to prevent sediment laden runoff entering the watercourse.  Compliance with the relevant sections of BS6031:2009 Code of Practice for Earthworks (British Standards, 2009) with respect to protection of water quality and control of site drainage including washings, dewatering, abstractions and surface water.  Safe containment of chemicals, use of drip trays and provision of emergency spill kits.

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 The use of silt fences, silt traps, filter bunds, settlement basins and/or proprietary units such as a ‘siltbuster’ to treat sediment laden water generated on site before discharge.  Availability of oil absorbent booms on site to be deployed in the event of a significant spillage.  Regular inspection of control and treatment measures to ensure they are working effectively.  Regular checking of construction plant for oil and fuel leaks, particularly when construction works are undertaken in or near the existing site water bodies.  Collection of waste fuels and other fluid contaminants in leak-proof containers prior to removal from construction site to an approved recycling processing facility.  Concrete mixing and washing areas shall be located more than 10m from any watercourse; have settlement and re-circulation systems for water reuse; have a contained area for washing out of concrete batching plant or ready-mix lorries; and collect wash-waters and, where necessary, contain wash-water for authorised off-site disposal. Wash-water from concrete shall not be discharged into the watercourse.  Avoiding vehicle cleaning within 10m of watercourses.  Dewatering working areas to maintain a dry construction area and passing any water generated by the dewatering process through silt busters or sediment tanks prior to returning this water to the watercourses.  Dewatering as shallow groundwater is encountered, there may be a need to pass the water through a silt buster or settlement pond if the abstracted water has a high sediment load.  Lining any temporary excavations to prevent infiltration of contaminants to the groundwater. Managing flood risk  Adoption and implementation of a Flood Evacuation Plan.  Sign up for flood warnings and check online warnings regularly.  Avoid works during high flow events and intense rainfall events.  Site compound(s) located outside of the floodplain.  Do not store materials and mobile machinery within the floodplain;  Implementation of an effective construction phase plan to construct the floodplain compensation basin and flood mitigation bund prior to construction works on the Main Carriageway. Flood management 8.5.16. Methods to reduce flood risk to construction workers are included in the CEMP measures listed above. Groundwater dewatering requirements 8.5.17. Groundwater levels and local geological conditions at locations of proposed below ground excavations should be investigated during an additional stage of Ground Investigation. This will allow to establish dewatering requirements during construction. 8.5.18. If groundwater dewatering is required, a dewatering strategy should be developed aiming to keep groundwater level and groundwater flow impacts to a local scale, also considering proximity to groundwater receptors including GWDTEs.

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LIKELY SIGNIFICANT RESIDUAL EFFECTS 8.5.19. Increased sedimentation was identified as causing a moderate adverse magnitude of impact on the water environment, resulting in a direct, short-term effect of large significance. This was due to the potential entrainment of significant volumes of loose sediment washing into nearby watercourses, subsequently impacting the chemical and ecological quality of the water bodies. 8.5.20. The mitigation measures recommended in the Outline CEMP to control sediment on Site, if adopted, are expected to minimise the magnitude of impact of increased sedimentation to minor adverse, therefore resulting in a direct, short-term residual effect of slight significance, which is considered not significant. 8.5.21. Implementation of an effective construction phase plan to construct the floodplain compensation basin and flood mitigation bund prior to construction works on the Main Carriageway, to ensure overall floodplain storage is minimised throughout the duration of the construction period, will likely result in a negligible magnitude of impact on downstream receptors. 8.5.22. Implementation of a Flood Evacuation Plan and checking of flood warnings will further minimise the risk (including to construction workers) as mobile plant and other materials can be relocated, with a negligible magnitude of impact. Overall, the adverse effects associated with flood risk are reduced to a direct, short-term residual effect of slight significance, which is considered not significant. 8.5.23. In the event of required groundwater dewatering during construction and following implementation of a groundwater dewatering strategy, the magnitude of residual impact on groundwater flow within the superficial deposits aquifer is considered minor adverse to negligible (local and temporary impact) resulting in a direct, short-term residual effect of slight to neutral significance, which is considered not significant. CUMULATIVE EFFECTS Cumulative effects Chapter 7: Biodiversity and Chapter 10: Geology and Soils (Volume II of the 2019 ES) discuss further construction mitigation measures relevant to the water environment. These mitigation measures are consistent with those outlined in this Chapter and the requirements to manage effects through the CEMP. There are no intra-project cumulative effects to identified water environment receptors associated with the Proposed Scheme that have not already been considered in this assessment and the residual operational effects of the Proposed Scheme on the water environment remain unchanged. Combination effects 8.5.24. There are three committed developments which could contribute to cumulative effects to the water environment during construction in combination with the Proposed Scheme: Dallington Grange Residential Development, Buckton Fields and Welford Road. A more detailed description of these developments is included in Chapter 3: Approach to EIA (Volume II of the ESA). Cumulative effects during the construction phase are only expected if these schemes and the Proposed Scheme are to be constructed simultaneously.

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8.5.25. There is a chance that the Dallington Grange Residential Development could be constructed at the same time as the Proposed Scheme as planning was approved in October 2018. Part of Buckton Fields (East) is already built, and the western part was granted planning permission in November 2018 with the condition that works start before November 2020; therefore, this development could be constructed at the same time as the Proposed Scheme. Welford Road has not had planning approval granted yet and it is expected that this will not be constructed at the same time as the Proposed Scheme. The Buckton Fields ES concludes that construction impacts to the water environment are negligible as mitigation is to be put in place to manage potential impacts. 8.5.26. It is assumed that the construction of all these developments will implement similar methods to those outlined for the CEMP for the Proposed Scheme (see ‘Mitigation Measures’ section above), as these are standard methods of practice for site management in construction. If all sites are adhering to these measures and individually have negligible impacts during the construction phase, the cumulative effect to water quality and water ecology is considered to be neutral and not significant and therefore the overall effect of the Proposed Scheme is unchanged and is not significant. 8.6 EFFECTS ARISING FROM OPERATION PRIMARY MITIGATION MEASURES 8.6.1. The infrastructure identified as part of the Proposed Scheme is presented in Chapter 3: Description of the Proposed Scheme (Volume II of the 2019 ES) and Chapter 2: Changes to the Description of the Proposed Scheme (Volume II of the ESA). Key mitigation measures of specific relevance to the assessment of operational effects that are incorporated into the Proposed Scheme design are outlined below: Managing pollution of waterbodies  Filter drains will be implemented along straight sections of the Proposed Scheme.  Three highway balancing ponds with associated flow control devices are proposed to attenuate surface water runoff from the section of the Proposed Scheme to the north of the railway line. Two are located in close proximity to each other north of Brampton Brook and to the east of the Main Carriageway. The third is located to the south of the Causeway.  The Main Carriageway south of the railway is drained to a swale for attenuation and treatment before being discharge to the River Nene.  The base of the highway balancing ponds will be lined with either clay or a geo-textile to reduce infiltration and pollution risk to groundwater.  Highway balancing ponds will be raised above fluvial flood levels to prevent flood water ingress. Managing flood risk  The three highway balancing ponds as described above will attenuate runoff to the north of the railway line.  Oversized pipes with associated flow control devices are proposed to attenuate surface water run-off from the section of the Proposed Scheme to the south of the Milton Keynes to Rugby railway line. Further co-operation with Dallington Grange developers is proposed to investigate the potential to tie into the Dallington Grange balancing ponds.  The Main Carriageway south of the railway that is drained to a swale that will attenuate runoff.  Two large flood relief culverts beneath the Main Carriageway to transfer flood flows from River Nene to floodplain east of the Main Carriageway.

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 Two large flood relief culverts underneath the Causeway will transfer flood flows of the River Nene downstream of the Causeway.  Excavation of the existing floodplain to the west of the Main Carriageway will offset some of the floodplain lost beneath the Main Carriageway.  A flood storage replacement area north of the Milton Keynes to Rugby railway line to the east of the Proposed Scheme will mitigate lost fluvial floodplain storage associated with the new embankment.  An earth flood mitigation bund will be constructed within the floodplain downstream of the Proposed Scheme to attenuate peak hydrograph flows.  The Kingsthorpe Ditch (surface water drain) will be diverted around the flood mitigation bund to maintain hydraulic connectivity and avoid the need for culverting. Managing impacts to hydrology  Two surface water drains will be routed under the Main Carriageway to maintain flow routes to two land drains which discharge to the River Nene. These will convey surface water runoff and are distinct from the various flood relief culverts.  Proposed crossings of the Brampton Brook and River Nene do not realign the watercourses and are clear spanning bridges. Managing impacts to WFD status  Clear span bridge construction is proposed over the River Nene. The bridge will be constructed so the abutments are approximately 6m away from bank top on either side. The watercourse channel will maintain a similar cross section profile to the existing channel and there will be no change to the existing riverbed profile.  Clear span bridge construction is proposed over Brampton Brook. The bridge will be constructed so the abutments are offset from the channel bed. The watercourse channel will maintain a similar cross section profile to the existing channel and there will be no change to the existing riverbed profile.  The diversion of Kingsthorpe Ditch will incorporate a number of meanders and be planted will appropriate vegetation to replicate the lowland fen habitat of this watercourse. ASSESSMENT OF EFFECTS Pollution Risks 8.6.2. A description of the surface water drainage strategy is provided in the standalone FRA, please refer to Appendix 8.3: Flood Risk Assessment (Volume III of the ES). The proposals for managing pollution include filter drains and highway balancing ponds. 8.6.3. The results of the HEWRAT assessment can be found in Appendix 8.2: Drainage Network Water Quality Assessment (Volume III of the ESA). The results of both the assessment of impact of routine runoff and assessment increased spillage risk to receiving watercourses demonstrate that there will not be a significant impact on the receiving surface water features as a result of the Proposed Scheme. The HEWRAT concludes that the Proposed Scheme passes both the acute- soluble and chronic-sediment related pollutant assessments and the spillage assessment concludes that the Proposed Scheme has a risk of pollution from spillage of less than 0.5%.

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8.6.4. The proposed highway balancing ponds and the restricted discharge rates have been taken into consideration as mitigation within the assessments. As a result, the Proposed Scheme will provide an appropriate level of treatment to the surface water runoff discharged into the watercourses. 8.6.5. The importance of the River Nene and the Brampton Brook are high. The magnitude of impact on water quality associated with the routine highway runoff to surface waters and the risk of spillage incidents on the highway is deemed to be negligible. This has been determined by the completion of the HEWRAT assessment as discussed above. Therefore, there is likely to be a direct, long-term slight effect during the operation phase, which is considered not significant. 8.6.6. The importance of the superficial deposits and the bedrock groundwater resources is medium. No highway runoff is proposed to be discharged to ground therefore the magnitude of impact on groundwater quality associated with the routine highway runoff and the risk of spillage incidents on the highway is deemed to be negligible. Similarly, the impact to groundwater quality associated with discharge to the surface water ditch (noting this is likely to have a Q95 flow of less than 1 l/s) is also considered to be negligible as the geology of the area will not accommodate much infiltration to ground. Therefore, there is likely to be a direct, long term slight effect, which is considered not significant. 8.6.7. Table 8-10 provides a summary of the likely effects associated with pollution risk to each receptor identified in the assessment.

Table 8-10: Impacts during operation arising from pollution risks

Receptor Comments Magnitude Significance of Impact of Effect

River Nene HEWRAT assessment concludes that there is no Negligible Slight significant impact to water quality from routine runoff or risk of spillage. Sufficient mitigation is incorporated in drainage design to treat surface water before discharge to River Nene.

Brampton No highway runoff is proposed to discharge directly to No change Neutral Brook the Brampton Brook.

Groundwater No highway runoff is proposed to discharge directly to Negligible Slight resources the ground.

Changes to hydrology 8.6.8. Figure 8-2 (Volume IV of the ESA) shows the existing drainage catchments that currently discharge to the River Nene as overland flow paths. 8.6.9. The Main Carriageway will cut off the existing overland flow routes from the catchments shown in Figure 8-2 (Volume IV of the ESA). 8.6.10. Drainage ditches will be constructed running parallel to the Main Carriageway along its western side. The drains will collect runoff from the catchments and divert flows as follows:  Red catchments will be diverted to a natural low point and conveyed beneath the Main Carriageway through the surface water pipe to the north.

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 Green catchments will be diverted southwards to an existing drain and conveyed beneath the Main Carriageway through the surface water culvert to the south. An existing drain at the north of the green catchments will be permanently cut off. On the eastern side of the culvert, the drain will receive the outfalls from two of the highway balancing ponds.  Purple catchments will be diverted southwards to Brampton Brook and conveyed beneath the Main Carriageway through the Brampton Brook bridge crossing. 8.6.11. The proposed ditches change the hydrological regime of the overland flow from the catchments to the west. The catchment area of the catchments shown in red, green and purple are 40ha, 40ha and 10ha respectively. The catchment areas of the River Nene and Brampton Brook at this location are approximately 200km2 and 30km2, respectively. The change in flows will therefore have negligible impact on hydrology within these watercourses. 8.6.12. The existing overland flow paths that are to be diverted comprise ephemeral ditches that hold no significant aquatic value.

8.6.13. The importance of the River Nene and the Brampton Brook is considered to be high. The magnitude of impact associated with the changes to catchment hydrology is considered to be negligible. Therefore, there is likely to be a direct, long-term effect of slight significance on the River Nene and Brampton Brook, which is considered not significant. 8.6.14. The importance of the golf course drainage ditches is considered to be low and the magnitude of the impact negligible. Therefore, there is likely to be a direct, long-term effect of slight significance to these ditches, which is considered not significant. 8.6.15. Table 8-11 provides a summary of the likely impacts associated with the changes to catchment hydrology to each relevant receptor discussed above.

Table 8-11: Impacts during operation arising from changes to hydrology

Receptor Comments Magnitude of Significance of Impact Effect

River Nene Diversion of flows does not remove flows from Negligible Slight catchment and flow diversion route is of similar length to the existing flow path.

Brampton Brook Diversion of flows does not remove flows from Negligible Slight catchment and flow diversion route is of similar length to the existing flow path.

Golf course Overland flow routes are not considered to support Negligible Slight drainage aquatic life. ditches Impacts to Groundwater and GWDTEs 8.6.16. To assess impacts on groundwater flow and groundwater levels from the construction of impermeable below ground structures (bridge foundations, lined ponds), further groundwater investigation will be required to confirm groundwater levels and local geological and hydrogeological conditions at the specific locations of proposed below ground structures.

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8.6.17. Impacts only arise where new structures extend below the groundwater table. Consequences, in terms of groundwater flow and level changes (including potential groundwater flooding and water level changes in the GWDTEs) depend on the ability of the groundwater to use alternative flow paths, i.e. flow around introduced flow barriers. Based on the current information, a receptor importance of medium and a potential magnitude of impact of moderate adverse are considered appropriate, highlighting the potential impact to local water supplies and GWDTEs and the importance of further investigation and potentially mitigation. This results in a potential direct, long- term adverse effect of moderate significance. Considering the high importance of the GWDTEs, the significance of effects would also be moderate, which is considered significant. 8.6.18. Table 8-12 provides a summary of the likely impacts to groundwater and GWDTEs during the operations phase.

Table 8-12: Impacts during operation to groundwater and GWDTEs

Receptor Comments Magnitude of Significance Impact of Effect

Superficial deposits Impacts will be dependent on local Moderate Moderate aquifer and hydrogeological conditions and detailed design adverse GWDTEs details. Flood Risk 8.6.19. A detailed assessment of the impacts associated with flood risk is provided in Appendix 8.1: Flood Risk Assessment (Volume III of the ESA). This highlights that there are permanent impacts caused by the introduction of barriers in the floodplain and the proposed highway drainage system. In summary, these changes are as follows:  Increased upstream flood risk and reduced downstream flows on the River Nene resulting from the construction of the Causeway.  Increased upstream flood risk and reduced downstream flows on the Brampton Brook resulting from the construction of the Main Carriageway.  Reduced floodplain attenuation and increased downstream flows on the River Nene resulting from the construction of the Main Carriageway.  Decreased downstream flows on the River Nene resulting from the construction of the flood attenuation bund.  Increased rates and volumes of surface water runoff from an increase in impermeable area or changes to the existing drainage regime leading to a potential increase in flood risk. 8.6.20. As detailed above, the effects of the Proposed Scheme comprise elements that increase and decrease downstream flows on the River Nene. The Proposed Scheme incorporates a series of culverts beneath the Causeway and Main Carriageway that dictate the balance of these flood risk mechanisms. The Proposed Scheme has been determined iteratively to minimise the increases in upstream flood risk whilst considering the capacity of the local area to offset the increases in downstream flood risk through the flood storage replacement area and flood attenuation bund. 8.6.21. The Proposed Scheme will result in an increase in water levels upstream of the Causeway. This increase in water levels varies from around 50mm in the 20yr event and in the region of 150mm in the 200yr+65% event. A single residential property and the A5199 Northampton Road are currently predicted to be impacted by increases in water levels in events smaller than the 200yr+65% event.

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8.6.22. The Boughton Mill Equestrian Centre riding track and Boughton Mill will be marginally impacted by an increase in 200yr+65% flood extent. Additional information is needed to confirm if the various buildings of Boughton Mill are put at increased risk of flooding as this seems unlikely based on the proposed model extents. There will be a marginal change in the flood frequency to the properties. 8.6.23. The Proposed Scheme will reduce risk of flooding to the Northamptonshire County Golf Course from the River Nene, while increasing the risk to the golf course from the Brampton Brook. The golf course is not considered to be a sensitive receptor. 8.6.24. The Main Carriageway will act as a barrier to the existing floodplain. This will increase downstream flows and hence flood risk to downstream properties including the town of Northampton. The Proposed Scheme incorporates a flood storage replacement area and flood mitigation bund to offset this change in flood risk. Appendix 15.3: Flood Risk Assessment (Volume III of the ESA) demonstrates that these provide a viable mitigation option and there is no increase in downstream flows. 8.6.25. The residential property upstream of the Proposed Scheme is considered to have high importance as they are classed as a more vulnerable property type. The Boughton Mill Equestrian Centre riding track and Boughton Mill are considered to have moderate importance as these are classed as less vulnerable property types. As discussed above, flood levels upstream of the Proposed Scheme are predicted to increase by more than 100mm during the 200yr+65% event. The Proposed Scheme is therefore predicted to have an impact of major adverse magnitude on flood risk to upstream properties. Therefore, the Proposed Scheme is likely to have a direct, long-term adverse effect of large significance for all upstream properties, which is considered significant. 8.6.26. Properties and land downstream of the Proposed Scheme are considered to have high importance as there are residential and commercial properties currently protected by the floodplain, upon which the Proposed Scheme is to be built. The magnitude of impact is predicted to be negligible as flood levels downstream are not predicted to increase by more than 10mm with the inclusion of proposed primary mitigation. Therefore, the effects will be of slight significance, which is considered not significant. 8.6.27. There will be an increase in impermeable surfaces following the construction of the Main Carriageway and the Causeway. Two highway balancing ponds will attenuate runoff from the Main Carriageway to the north of the Milton Keynes to Rugby railway to 5l/s. Runoff from the Causeway is managed by a single balancing pond for the Causeway itself and an online hydraulic control for Brampton Lane roundabout. The combined runoff from the Causeway is attenuated to 5l/s. The 5l/s flow is larger than the calculated greenfield runoff conditions but has been adopted to manage blockage risk in the highway balancing ponds outfall structures. In comparison, the 2yr flow on the River Nene of 24m3/s or 24,000l/s, as such this flow is considered appropriate. Oversized pipes within the drainage system will do the same for the runoff from the surfaces to the south of the Milton Keynes to Rugby railway. Following this mitigation, there will be a negligible change to runoff from existing greenfield runoff. Properties and land downstream of the Proposed Scheme are considered to have high importance. Therefore, the effect will be of slight significance, which is considered not significant. 8.6.28. Table 8-13 provides a summary of the likely impacts associated with the changes to flood risk during the operations phase.

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Table 8-13: Impacts during operation arising from increased flood risk

Receptor Comments Magnitude of Significance Impact of Effect

Properties and land Increased flood risk to the town of Negligible Slight downstream and Northampton, located immediately within Northampton downstream of proposed works in area known to be sensitive to flooding. However, considering the embedded mitigation of the flood replacement storage area and flood attenuation bund, this will provide adequate storage for the lost floodplain. Surface water runoff will be attenuated to a maximum discharge of 5 l/s from each outfall.

Residential and The Proposed Scheme will result in increases Major adverse Large commercial flood depth and marginal increases in flood properties and the frequency. A5199 upstream of the Causeway

Boughton Mill The Proposed Scheme will result in increases Major adverse Moderate Equestrian Centre flood depth in the vicinity of these properties riding track and and marginal increases in flood frequency. Boughton Mill Additional information is needed to confirm if the various buildings of Boughton Mill are put at increased risk of flooding as this seems unlikely based on the proposed model extents. Impacts to Water Framework Directive Status 8.6.29. The WFD monitors the hydromorphological, chemical and ecological quality of watercourses. The impact of the operational phase of the Proposed Scheme on the WFD status of the relevant waterbodies is assessed in a separate WFD assessment (Appendix 3.10: Water Framework Directive Assessment (Volume III of the ESA)). Table 4-11 and Table 4-12 in the WFD assessment set out the potential impacts of the Proposed Scheme on the River Nene and Brampton Brook respectively. 8.6.30. The Proposed Scheme crosses the River Nene and Brampton Brook. In both instances, the proposed crossings will be a clear span bridge type structure. 8.6.31. The bridge abutments for the River Nene crossing will be set back from the banks by approximately 6m. As such, there will be no requirement for hard structures within the bed of the River and a natural bed will be maintained following construction. Sheet piling will be installed on the banks of the watercourse to protect from erosion. This will result in a permanent loss of bankside vegetation. 8.6.32. The importance of the River Nene is considered to be high. For the assessment of longer-term operational impacts, the magnitude of impact on hydromorphology is considered to be moderate adverse as the Proposed Scheme will result in partial loss of riparian habitat that forms an attribute of hydromorphological water quality. Therefore, the Proposed Scheme is likely to have an effect of moderate significance on the hydromorphology of the River Nene, which is considered significant.

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8.6.33. The bridge abutments for the Brampton Brook crossing will be offset from the channel. As such, there will be no requirement for hard structures within the bed of the watercourse and a natural bed will be maintained following construction. Sheet piling will be installed on the banks of the watercourse to protect from erosion and the length of the structure will limit light reaching the watercourse for its full length. This will result in a permanent loss of bankside vegetation. 8.6.34. The importance of the Brampton Brook is considered to be high. There is likely to be a direct, long- term moderate adverse magnitude of impact on the Brampton Brook associated with the partial loss of riparian habitat. The significance of effect of the Proposed Scheme on the hydromorphology of the Brampton Brook is therefore considered to be moderate, which is considered significant. 8.6.35. Table 8-14 provides a summary of the likely impacts to the water environment associated with the operation phase of the proposed culverts and engineered channel.

Table 8-14: Impacts to the water environment during operation arising from changes to hydromorphology

Receptor Comments Magnitude Significance of of Impact Effect

River Nene The hydromorphological quality of the watercourse will be Moderate Moderate maintained with the provision of a clear span structure, adverse although some loss of riparian habitat will occur.

Brampton The mitigation measure embedded with the design of the Moderate Moderate Brook proposed culvert and engineered channel will reduce the adverse impact on the Brampton Brook, principally the retention of the natural bed and watercourse alignment, although some loss of riparian habitat will occur. LIKELY SIGNIFICANT RESIDUAL EFFECTS 8.6.36. The assessment has identified significant impacts to: • A residential and two commercial properties upstream of the Proposed Scheme from flood risk • Groundwater and GWDTEs • Water Framework Directive Status 8.6.37. The Proposed Scheme will result in an increase in flooding to a residential property and the A5199. Boughton Mill Equestrian Centre riding track and Boughton Mill will be marginally impacted by an increase in 200yr+65% flood extent. Additional information is needed to confirm if the various buildings of Boughton Mill are put at increased risk of flooding as this seems unlikely based on the proposed model extents. There will be an increase in flood depth of between 0.05m and 0.15m dependent on the magnitude of the event and hence a minor increase in the frequency of flooding to these receptors. For these properties the Proposed Scheme does not pass Part 3 of the Exception Test as set out in Appendix 8.1: Flood Risk Assessment (Volume III of the ESA) and agreement will be needed with the landowners to confirm the change in flood risk is acceptable. The residual effect of the Proposed Scheme will be a direct, long-term adverse effect of large to moderate significance, which is considered significant. If agreement with landowners is not forthcoming further measures will be required to manage the change in flood risk to these properties.

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8.6.38. There is a potential direct, long-term adverse effect of moderate significance on groundwater flow and groundwater levels from the construction of below ground structures (bridge foundations, flood storage replacement area and borrow pits) which is considered significant. Further Ground Investigation will be required in the areas with proposed below ground structures. This relates to the flood storage replacement area and borrow pits which could introduce a partial or almost complete barrier for groundwater flow towards the river resulting in groundwater flow diversions. If below ground structures extend below the groundwater table, a hydrogeological assessment will be required to assess the impacts on groundwater and groundwater receptors (including impacts on baseflow to surface water features and GWDTEs). With a good understanding of the local hydrogeological conditions and the potential impacts, mitigation measures can be built into the detailed design (e.g. drainage layers underneath and next to the ponds to offer alternative pathways), if required. 8.6.39. The Proposed Scheme will result in loss of riparian habitat at the River Nene and Brampton Brook crossing location. Therefore, there will be a direct, long-term adverse effect of moderate significance which is considered significant. Table 4-11 and Table 4-12 in the WFD assessment (Appendix 3.10: Water Framework Directive Assessment (Volume III of the ESA)) set out the appropriate mitigation requirements for the River Nene and Brampton Brook respectively. Appropriate mitigation in the form of compensatory riparian planting and habitat creation will be implemented to offset and neutralise the anticipated impacts of the Proposed Scheme. Full details of the planting regime will be provided in the Habitat Management Plan to be developed as part of the detailed design stage as set out in the construction mitigation measures in Chapter 7: Biodiversity (Volume II of the 2019 ES). On this basis the WFD assessment concludes that the Proposed Scheme with compensatory riparian planting is not expected to cause degradation of the WFD status, nor prevent the relevant water bodies from achieving their WFD objectives. Therefore, the residual effect to WFD status is considered to be of neutral significance, which is considered not significant. CUMULATIVE ASSESSMENT Cumulative effects 8.6.40. Chapter 7: Biodiversity and Chapter 10: Geology and Soils (Volume II of the 2019 ES) discuss further operational primary mitigation measures relevant to the water environment that have not been discussed explicitly in this Chapter. These mitigation measures consist the sizing of culverts to support mammal passage and associated mammal ledges. There are no intra-project cumulative effects to identified water environment receptors associated with the Proposed Scheme that have not already been considered in this assessment and the residual operational effects of the Proposed Scheme on the water environment remain unchanged. Combination effects 8.6.41. There are three committed developments which could contribute to cumulative effects to the water environment in combination with the Proposed Scheme: Dallington Grange Residential Development, Buckton Fields and Welford Road. A more detailed description of these developments is included in Chapter 3: Approach to EIA (Volume II of the ESA). 8.6.42. Regarding impact to the water all developments are within Flood Zone 1 and as such will not contribute to flood risk from fluvial sources. In combination effects are therefore associated with the drainage design of these developments and the resulting impacts.

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8.6.43. The planning applications have been reviewed and the drainage strategies in place for the Dallington Grange and Buckton Fields developments are in accordance with the Non-Statutory Technical Standards for Sustainable Drainage Systems (2015) (Ref. 8-5) and the NPPF. As such these confirm that water quality is not reduced, and flood risk is not increased as a result of the development(s). The Welford Road development site drainage strategy demonstrates no increase in greenfield runoff rates. An assessment of water quality could not be located but it is a requirement of the NPPF that water quality is not reduced. This in conjunction with the demonstration that the Proposed Scheme will provide an appropriate level of treatment to the surface water runoff discharged into the watercourses means it is appropriate to conclude that there is negligible magnitude of impact to the water environment associated with water quality or flood risk. Therefore, cumulative effects can be deemed neutral, which are considered not significant. 8.7 MONITORING 8.7.1. Additional Ground Investigation and associated groundwater monitoring is required in the areas with proposed impermeable below ground structures to inform the requirements for a hydrogeological assessment and the scale of mitigation measures required in the detailed design. 8.7.2. Environmental monitoring, to include the monitoring of surface watercourses and groundwater, will be undertaken in accordance with the requirements outlined within the CEMP throughout the construction phase of the Proposed Scheme and ongoing monitoring of the drainage system will be completed throughout the lifespan of the scheme. 8.7.3. The is a significant and permanent operational residual effect on flood risk associated with the Proposed Scheme. Further consultation with the Environment Agency and Northamptonshire County Council will be undertaken through detailed design to confirm any future monitoring. requirements. 8.8 REFERENCES  Ref. 8-1: Highways Agency (2019) Design Manual for Roads and Bridges. Highways England.  Ref. 8-2: WSP (2020) North-West Relief Road Planning Statement, Northamptonshire County Council  Ref. 8-3: Northamptonshire County Council (2017) Local standards and guidance for surface water drainage in Northamptonshire, Northamptonshire County Council  Ref. 8-4: Environment Agency (2018) The Environment Agency’s approach to groundwater protection, Environment Agency  Ref. 8-5: Defra (2015) Sustainable Drainage Systems, Non-statutory technical standards for sustainable drainage systems, Department for Environment, Food and Rural Affairs.  Ref. 8-6: CIRIA (2001) Control of water pollution from construction sites, Guidance for consultants and contractors (C532). Masters-Williams, H, Heap A, Kitts, H, Greenshaw, L, Davis, S, Fisher, P, Hendrie, M, Owens, D. CIRIA, London.  Ref. 8-7: CIRIA (2006) Control of water pollution from linear construction projects, Technical guidance (C648). Murnane, E, Heap, A, Swain, A. CIRIA, London.  Ref. 8-8: CIRIA (2016) Groundwater control: design and practice (second edition) (C750). Preene, M, Roberts, TOL, Powrie, W. CIRIA, London.  Ref. 8-9: CIRIA (2015) The SuDS Manual (C753). Woods Ballard, B, Wilson, S, Udale-Clarke, H, Illman, S, Scott, T, Ashley, R, Kellagher R. CIRIA, London.

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 Ref. 8-10: Service.gov.uk. 2019. Service.gov.uk. [Online]. [31 May 2019]. Available from: https://flood-warning-information.service.gov.uk/long-term-flood-risk/map  Ref. 8-11: Data.gov.uk. 2019. Data.gov.uk. [Online]. [31 May 2019]. Available from: https://environment.data.gov.uk/catchment-planning/  Ref. 8-12: Service.gov.uk. 2019. Service.gov.uk. [Online]. [31 May 2019]. Available from: https://flood-map-for-planning.service.gov.uk/  Ref. 8-13: Bgs.ac.uk. 2019. Bgs.ac.uk. [Online]. [31 May 2019]. Available from: http://mapapps.bgs.ac.uk/geologyofbritain/home.html  Ref. 8-14: Environment Agency (2013) Upper Nene Model Report, Nene Flood Map Improvements Project. Environment Agency.  Ref. 8-15: British Geological Survey (1990) Geological Survey of England and Wales Sheet 185, Solid and Drift Geology, 1:50000. Northampton, British Geological Survey.  Ref. 8-16: Defra.gov.uk. 2019. Defra.gov.uk. [Online]. [31 May 2019]. Available from: https://magic.defra.gov.uk/magicmap.aspx  Ref. 8-17: Bgs.ac.uk. 2019. Bgs.ac.uk. [Online]. [31 May 2019]. Available from: https://www.bgs.ac.uk/geoindex/  Ref. 8-18: Environment Agency (1997) The physical properties of minor aquifers in England and Wales. British Geological Survey Technical Report WD/00/4. R&D Publication 68. Jones, H, K, Morris, B, L, Cheney,C, S, Brewerton, L, J, Merrin, P, D, Lewis, M, A, MacDonald, A, M, Coleby, L, M, Talbot, J, C, McKenzie, A, A, Bird, M, Cunningham, J, J, Robinson, V, K. Environment Agency.  Ref. 8-19: West Northamptonshire Joint Planning Unit (2014) West Northamptonshre Joint Core Strategy Local Plan (Part 1). West Northamptonshire Joint Planning Unit  Ref. 8-20: LA 113 Road drainage and the water environment (formerly HD 45/09). Revision 1 (March 2020), Highways England.  Ref. 8-21: LA 104 Environmental Assessment and Monitoring (formerly HD 205/08). Revision 1 (March 2020), Highways England.  Ref. 8-22: Factual Ground Investigation Report (Phase 2) January 2020 NWRR-WSP-VGT-0000- RP-CE-00002  Ref. 8-23: Envirocheck.co.uk. 2019. Envirocheck.ac.uk. [Online]. [31 May 2019]. Available from: http://www.envirocheck.co.uk/

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9 SUMMARY OF EFFECTS

9.1 INTRODUCTION 9.1.1. This chapter summarises the relevant construction and operational phase effects upon receptors that have been found to be ‘significant’ before mitigation (incorporating primary mitigation only). The significance of effects after mitigation are termed ‘residual effects’. Significance levels are classified, as detailed in Chapter 3: Approach to the EIA (Volume II of the ESA) unless otherwise stated. 9.1.2. This chapter outlines the summary of effects presented in Technical Chapters 4-8. For the summary of effects of the technical chapters scoped out of the ESA, please refer to Chapter 16: Summary of effects (Volume II of the 2019 ES). 9.2 AIR QUALITY 9.2.1. No significant effects (before mitigation) were identified in relation to air quality receptors. 9.3 CLIMATE CHANGE 9.3.1. No significant effects (before mitigation) were identified in relation to GHG emissions. 9.3.2. As noted in Table 3-2, the ESA does not revisit the climate change vulnerability assessment. Please refer to Chapter 16: Summary of Effects (Volume II of the 2019 ES) for further detail of residual effects in relation to the vulnerability and resilience of the Proposed Scheme. 9.4 LANDSCAPE AND VISUAL 9.4.1. Table 9-1 presents a summary of landscape and visual effects relating to the new or amended receptors impacted by the changes to the baseline and Proposed Scheme. 9.4.2. For further details of the landscape and visual effects reported in the 2019 ES, please refer to Chapter 11: Landscape and Visual (Volume II of the ES) and Chapter 16: Summary of Effects (Volume II of the ES).

Table 9-1: Summary of Landscape and Visual effects

Description Significance and Summary of Significance and Nature of Effects Mitigation Nature of Residual with Primary Effects Mitigation

Construction Phase

Visual Impacts – Residential Receptors

Welford Rd. Development Very large adverse - Very large adverse (temporary), (temporary), significant. significant.

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Description Significance and Summary of Significance and Nature of Effects Mitigation Nature of Residual with Primary Effects Mitigation

Buckton Fields (West) development Large adverse - Large adverse (temporary) (temporary) during significant. construction significant.

Operational Phase

Visual Impacts – Residential Receptors

Welford Rd. Development Large Adverse Landscape Moderate Adverse (permanent), mitigation planting (permanent), year 15, significant significant

Welford Rd. Development Large Adverse Landscape Moderate Adverse (operational) mitigation planting (permanent), year 15, significant significant

Buckton Fields (West) development Moderate to large Landscape Moderate Adverse adverse (permanent) mitigation planting (permanent), year 15, significant significant

Buckton Fields (West) development Large adverse Landscape Moderate Adverse (operational) on mitigation planting (permanent), year 15, completion significant. significant,

9.5 NOISE AND VIBRATION 9.5.1. Table 9.2 presents a summary of effects on noise and vibration receptors.

Table 9-2: Summary of Noise and Vibration effects

Receptor Description of Significance and Summary of Significance and Effects Nature of Effects Mitigation Nature of with Primary Residual Effects Mitigation

Construction

Residential Construction noise Moderate Best practice Negligible to minor properties, magnitude, up to measures and magnitude schools, care major adverse, implementation of adverse, direct, homes and direct, temporary, the CEMP. temporary, short- community short-term, term, not facilities located significant at significant at near to the Site closest receptors closest receptors

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Receptor Description of Significance and Summary of Significance and Effects Nature of Effects Mitigation Nature of with Primary Residual Effects Mitigation

Construction Moderate Best practice Minor magnitude vibration magnitude, measures and adverse, direct, adverse, direct, implementation of temporary, short- temporary, short- the CEMP. term, not term, significant significant at at closest closest receptors receptors

Operation

Residential Increased toad Receptors Thin surface Receptors properties, care traffic noise identified as course system identified as homes moderate to major moderate magnitude of magnitude of impact, adverse impact, adverse, significant significant

Residential Reduction in road Receptors - Receptors properties, traffic noise identified as minor identified as minor schools, churches to major magnitude to major magnitude of impact, of impact, beneficial, beneficial, significant significant

9.6 ROAD DRAINAGE AND WATER ENVIRONMENT 9.6.1. Table 9-3 presents the summary of effects on road drainage and the water environment receptors.

Table 9-3: Summary of Road Drainage and Water Environment effects

Receptor Description of Significance and Summary of Significance and Effects Nature of Effects Mitigation Nature of Prior to Mitigation Residual Effects

Construction Phase

River Nene Increased Moderate Best practice Not significant sedimentation magnitude, measures and within watercourse adverse, direct, implementation of short term, large the CEMP. significance, significant

Increased risk of Minor magnitude, Best practice Not significant pollution adverse, direct, measures and short term, implementation of moderate the CEMP. significance, significant

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Receptor Description of Significance and Summary of Significance and Effects Nature of Effects Mitigation Nature of Prior to Mitigation Residual Effects

Brampton Brook Increased Moderate Best practice Not significant sedimentation magnitude, measures and within watercourse adverse, direct, implementation of short term, large the CEMP. significance, significant

Increased risk of Minor magnitude, Best practice Not significant pollution adverse, direct, measures and short term, implementation of moderate the CEMP. significance, significant

Properties and Increased flood risk Major magnitude, Best practice Not significant A5199 upstream adverse, direct, measures and short term, large implementation of significance, the CEMP. significant

Properties and Major magnitude, Best practice Not significant land downstream adverse, direct, measures and within short term, large implementation of Northampton significance, the CEMP. significant

Boughton Mill Major adverse Best practice Not significant Equestrian Centre magnitude, direct, measures and riding track and short term, implementation of Boughton Mill moderate the CEMP. significance, significant

Operational Phase

Properties and Increase in flood Major magnitude, Agreement will be Moderate A5199 upstream risk adverse, needed with the magnitude, permanent, direct, landowners to adverse, long term, large confirm the change permanent, direct, significance, in flood risk is long term, large to significant acceptable. moderate If agreement with significance, landowners is not significant forthcoming further measures will be required to manage the change in flood risk to these properties.

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Receptor Description of Significance and Summary of Significance and Effects Nature of Effects Mitigation Nature of Prior to Mitigation Residual Effects

Boughton Mill Major magnitude, Agreement will be Moderate Equestrian Centre adverse, needed with the magnitude, riding track and permanent, direct, landowners to adverse, Boughton Mill long term, confirm the change permanent, direct, moderate in flood risk is long term, large to significance, acceptable. moderate significant If agreement with significance, landowners is not significant forthcoming further measures will be required to manage the change in flood risk to these properties

Superficial Moderate With a good Moderate deposits aquifer, magnitude, understanding of magnitude, GWDTE’s and adverse, the local adverse, properties adjacent permanent, long hydrogeological permanent, direct, to below ground term, moderate conditions and the long term, structures significance, potential impacts, moderate significant mitigation significance, measures can be significant built into the detailed design

River Nene Hydromorphological Moderate Appropriate Moderate impact -Loss of magnitude, mitigation set out magnitude, Riparian habitat adverse, direct, in WFD adverse, direct, long term, Assessment long term, moderate moderate significance, significance, Significant significant

Brampton Brook Hydromorphological Moderate Appropriate Moderate impact - Loss of magnitude, mitigation set out magnitude, Riparian habitat adverse, direct, in WFD adverse, direct, long term, Assessment long term, moderate moderate significance, significance, significant significant

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